Electrical and Electronics Engineering publications abstract of: 02-2018 sorted by title, page: 9

» Efficient Recommendation of Aggregate Data Visualizations
Abstract:
Data visualization is a common and effective technique for data exploration. However, for complex data, it is infeasible for an analyst to manually generate and browse all possible visualizations for insights. This observation motivated the need for automated solutions that can effectively recommend such visualizations. The main idea underlying those solutions is to evaluate the utility of all possible visualizations and then recommend the top-k visualizations. This process incurs high data processing cost, that is further aggravated by the presence of numerical dimensional attributes. To address that challenge, we propose novel view recommendation schemes, which incorporate a hybrid multi-objective utility function that captures the impact of numerical dimension attributes. Our first scheme, Multi-Objective View Recommendation for Data Exploration (MuVE), adopts an incremental evaluation of our multi-objective utility function, which allows pruning of a large number of low-utility views and avoids unnecessary objective evaluations. Our second scheme, upper MuVE (uMuVE), further improves the pruning power by setting the upper bounds on the utility of views and allowing interleaved processing of views, at the expense of increased memory usage. Finally, our third scheme, Memory-aware uMuVE (MuMuVE), provides pruning power close to that of uMuVE, while keeping memory usage within a pre-specified limit.
Autors: Humaira Ehsan;Mohamed A. Sharaf;Panos K. Chrysanthis;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Feb 2018, volume: 30, issue:2, pages: 263 - 277
Publisher: IEEE
 
» Efficient Wideband Computation of Electromagnetic Scattering by Finite Periodic Structures Combining ASED Basis Function With Frequency-Independent Reaction
Abstract:
An efficient wideband electromagnetic scattering analysis method for finite periodic structures by combining the accurate subentire-domain (ASED) basis function with the frequency-independent reaction (FIR) is presented. The ASED basis function is suitable for analyzing finite periodic structures with less unknowns than the conventional method of moments (MoM). Its efficiency is very high. However, it is a single-frequency technique and is still time-consuming for frequency sweep. The FIR can accelerate the frequency sweep, in which the exponential of the Green function is expanded in Taylor series. The impedance element is formulated as the sum of the series, where each term is the product of the geometry-dependent element and the phase factor. Recomputation of the former one is unnecessary during frequency sweep. Thus, it is very efficient. To test the accuracy of the proposed algorithm, several examples are implemented. Numerical results show that the results obtained using the proposed method agree well with those computed using the ASED basis function and conventional MoM. The efficiency of the proposed technique is also validated.
Autors: Ping Du;Gang Zheng;Cheng Wang;Wei Jie Fu;
Appeared in: IEEE Antennas and Wireless Propagation Letters
Publication date: Feb 2018, volume: 17, issue:2, pages: 234 - 237
Publisher: IEEE
 
» Eigenvalue-Based Urban Area Extraction Using Polarimetric SAR Data
Abstract:
Urban area extraction using polarimetric synthetic aperture radar (PolSAR) data has become a potential mean to urban studies because it holds the promise that the radar returns from specific scattering characteristics may be emphasized. Due to the high variability of urban land-scape and the existing misdetection of buildings as vegetation, urban area extraction is still a challenging problem. In this paper, an eigenvalue-based urban area extraction method is proposed. First, similar to the entropy/anisotropy plane, a two-dimensional RVI/PA plane is put forward to construct the extractor of buildings with small orientation angles. Second, coupled with the parameters, a robust extractor is introduced to elevate the scattering characteristics of buildings with large orientation angles but to suppress those of others. Finally, data-driven thresholds are investigated and ascertained for the extractors, thus urban areas are extracted. In addition, a change detection-based prescreening method is applied to refine the extraction result. The performance of the proposed method is demonstrated and validated with spaceborne and airborne fully PolSAR data over different test sites. The outputs show that the proposed method provides an overall accuracy of over 90%, as well as better visual results of the extracted buildings.
Autors: Sinong Quan;Boli Xiong;Deliang Xiang;Lingjun Zhao;Siqian Zhang;Gangyao Kuang;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Feb 2018, volume: 11, issue:2, pages: 458 - 471
Publisher: IEEE
 
» ElasticCore: A Dynamic Heterogeneous Platform With Joint Core and Voltage/Frequency Scaling
Abstract:
Heterogeneous architectures have emerged as a promising solution to address the dark silicon challenge by providing customized cores for each running application. To harness the power of heterogeneity, a critical challenge is simultaneously fine-tuning several parameters at the application, architecture, system, as well as circuit levels for heterogeneous architectures that improve the energy-efficiency envelope. To address this challenge, an ElasticCore platform is described where core resources along with the operating voltage and frequency settings are scaled to match the application behavior at run-time. A quantile linear regression model for power and performance prediction is used to guide the adaptation of the core resources, along with the operating voltage and frequency, to improve the energy efficiency. In addition, the dynamically scalable partitions of the ElasticCore are powered with multiple on-chip voltage regulators with high-power conversion efficiency that are able to realize fast dynamic voltage/frequency scaling. The results indicate that ElasticCore predicts application power and performance behavior with a small error at run-time across all studied benchmarks and achieves, on average close to 93% energy efficiency, as compared to an architecture with the Oracle power and performance predictor.
Autors: Mohammad Khavari Tavana;Mohammad Hossein Hajkazemi;Divya Pathak;Ioannis Savidis;Houman Homayoun;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Feb 2018, volume: 26, issue:2, pages: 249 - 261
Publisher: IEEE
 
» Electrically Small, Low-Profile, Huygens Circularly Polarized Antenna
Abstract:
The design, simulation studies, and experimental verification of an electrically small, low-profile, broadside-radiating Huygens circularly polarized (HCP) antenna are reported. To realize its unique circular polarization cardioid-shaped radiation characteristics in a compact structure, two pairs of the metamaterial-inspired near-field resonant parasitic elements, the Egyptian axe dipole (EAD) and the capacitively loaded loop (CLL), are integrated into a crossed-dipole configuration. The EAD (CLL) elements act as the orthogonal electric dipole (magnetic dipole) radiators. Balanced broadside-radiated electric and magnetic field amplitudes with the requisite 90° phase difference between them are realized by exciting these two pairs of electric and magnetic dipoles with a specially designed, unbalanced crossed-dipole structure. The electrically small (ka = 0.73) design operates at 1575 MHz. It is low profile , and its entire volume is only . A prototype of this optimized HCP antenna system was fabricated, assembled, and tested. The measured results are in good agreement with their simulated values. They demonstrate that the prototype HCP antenna resonates at 1584 MHz with a 0.6 dB axial ratio, and produces the predicted Huygens cardioid-shaped radiation patterns. The measured peak realized LHCP gain was 2.7 dBic, and the associated front-to-back ratio was 17.7 dB.
Autors: Wei Lin;Richard W. Ziolkowski;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2018, volume: 66, issue:2, pages: 636 - 643
Publisher: IEEE
 
» Electrifying Water Buses: A Case Study on Diesel-to-Electric Conversion in Venice
Abstract:
This study presents the conversion of a diesel-based watercraft for public transportation in Venice, Italy, to an electric propulsion technology, with a view to wide future adoption of electrical transportation. It takes into account energy-storage systems, electrical machines, and drives and examines them in light of economic, environmental, and social issues. Some alternative solutions based on hybrid diesel-electric and full-electric (FE ) powertrains are compared in terms of weight, cost, and payback times. The comparison shows that a hybrid diesel-engine lithium (Li) battery (LB) is the best option for an easy first implementation, even when considering the existing infrastructure.
Autors: Massimo Guarnieri;Mattia Morandin;Antonio Ferrari;Pierpaolo Campostrini;Silverio Bolognani;
Appeared in: IEEE Industry Applications Magazine
Publication date: Feb 2018, volume: 24, issue:1, pages: 71 - 83
Publisher: IEEE
 
» Electromagnetic Scattering from Deterministic Sea Surface With Oceanic Internal Waves via the Variable-Coefficient Gardener Model
Abstract:
In this paper, a hydrodynamic-electromagnetic model is proposed for analyzing the electromagnetic scattering characteristic of a multiscale deterministic sea surface with internal waves in a two-layer ocean system. A variable-coefficient Gardner model is applied to establish the profile of the internal waves, and the spectrum induced by a variable current is then derived by the action balance equation. The slope-deterministic facet-based two-scale method (SDFb-TSM) is used to calculate the scattering characteristics of the multiscale deterministic sea surface. The total coefficient distribution is then quantitatively obtained from this composite model considering Bragg resonance, tilting effect, and specular reflection effect. Numerical results show that the shape and modulated depth of normalized radar cross section induced by the internal soliton of the Gardner model agree quite well with the measured data. Thus, the Gardner model combined with the SDFb-TSM method performes better than the KdV model combined with statistical scattering methods for the prediction of scattering characteristics of a sea surface with internal waves. The variation in scattering signature characteristics for the depression internal wave are discussed for both one- and two-soliton cases. The influences on the scattering coefficients under different parameters of the internal wave, sea state, and radar system are analyzed. Furthermore, both overtaking-type and head-on-type internal waves are presented and the effect of the perturbed term on internal wave profiles and the scattering characteristics of both one- and two-soliton cases are discussed.
Autors: Xiaoxiao Zhang;Zhen-Sen Wu;Xiang Su;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Feb 2018, volume: 11, issue:2, pages: 355 - 366
Publisher: IEEE
 
» Electron Acceleration and Diffusion in the Gyrophase Space by Low-Frequency Electromagnetic Waves
Abstract:
Charged particle acceleration is a fundamental issue in many fields ranging from particle physics to spacecraft propulsion. In this paper, the interaction between electromagnetic waves and relativistic electrons is numerically studied. The effect of the initial gyrophase in a dipole magnetic field on electron acceleration by wave–particle interaction is found in a test particle code with various wave amplitudes. It is indicated that the initial gyrophase of the electrons plays a crucial role in the acceleration process.
Autors: Hua Huang;Xiao-Tian Gao;Xiao-Gang Wang;Zhi-Bin Wang;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Feb 2018, volume: 46, issue:2, pages: 225 - 229
Publisher: IEEE
 
» Electronic Interface for a Gas Sensor System Based on 32 MHz QCMs: Design and Calibration
Abstract:
This paper describes the design and development of a system of gas sensors based on quartz crystal microbalances (QCMs) to be used for the measurement of gas, vapors, and their mixtures. This system’s architecture manages an array composed of eight QCMs with a resonance frequency of about 32 MHz. Custom oscillator circuits were designed and built to drive the QCMs. A data acquisition stage was developed to collect the output frequencies of the QCMs array and to visualize and store the data. The QCMs have been functionalized with eight different types of anthocyanins, using two different techniques. Three of the QCMs composing the array have been tested, and their performance is compared to a previous array based on 20-MHz QCMs. One of the QCMs, covered via drop casting, when tested in a calibration experiment, shown an improved performance consisting in a ratio of 4.92 between 32- and 20-MHz sensitivities. This number confirmed the ratio of 5.76 theoretically calculated using Sauerbrey’s law. The other two QCMs tested were covered via spray casting, giving resolution of tens of ppb, comparable with the previous release.
Autors: Giorgio Pennazza;Marco Santonico;Alessandro Zompanti;Simone Grasso;Arnaldo D’Amico;
Appeared in: IEEE Sensors Journal
Publication date: Feb 2018, volume: 18, issue:4, pages: 1419 - 1426
Publisher: IEEE
 
» Electronically Tunable Fully Integrated Fractional-Order Resonator
Abstract:
A fully integrated implementation of a parallel fractional-order resonator that employs together a fractional-order capacitor and a fractional-order inductor is proposed in this brief. The design utilizes current-controlled operational transconductance amplifiers as building blocks, designed, and fabricated in AMS CMOS process and based on a second-order approximation of a fractional-order differentiator/integrator magnitude optimized in the range 10 Hz–700 Hz. An attractive benefit of the proposed scheme is its electronic tuning capability.
Autors: Georgia Tsirimokou;Costas Psychalinos;Ahmed S. Elwakil;Khaled N. Salama;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Feb 2018, volume: 65, issue:2, pages: 166 - 170
Publisher: IEEE
 
» Elevating Learner Achievement Using Formative Electronic Lab Assessments in the Engineering Laboratory: A Viable Alternative to Weekly Lab Reports
Abstract:
A laboratory pedagogy interweaving weekly student portfolios with onsite formative electronic laboratory assessments (ELAs) is developed and assessed within the laboratory component of a required core course of the electrical and computer engineering (ECE) undergraduate curriculum. The approach acts to promote student outcomes, and neutralize academic integrity violations, while refocusing instructor and teaching assistant roles toward high-gain instructional activities, such as personalized student tutoring. A mixed-method study evaluated the learning effectiveness and student satisfaction using biweekly ELAs versus traditional laboratory reports in a large-enrollment () undergraduate computer engineering laboratory course. The results of the evaluation indicate statistically significant effects on both learning outcomes and student satisfaction from the use of formative assessments in laboratory delivery, which were corroborated by the instructor’s reflections. Students in the ELA with tutoring enabled delivery cohort performed better on the post-test and were more satisfied with the laboratory assessment design and assistance received in laboratory than those in the control cohort. The findings offer a promising alternative for ECE and engineering laboratory instruction that fosters gains in practical skills and content mastery.
Autors: Baiyun Chen;Ronald F. DeMara;Soheil Salehi;Richard Hartshorne;
Appeared in: IEEE Transactions on Education
Publication date: Feb 2018, volume: 61, issue:1, pages: 1 - 10
Publisher: IEEE
 
» Emerging Trends, Issues, and Challenges in Big Data and Its Implementation toward Future Smart Cities: Part 2
Abstract:
Due to urbanization, smart cities are emerging as a priority for research and development across the world. However, the rapid progress in smart cities research is posing enormous challenges in terms of the large amounts and various types of data at an unprecedented granularity, speed, and complexity that are increasingly produced by IoT sensors via emerging communication technologies. Meanwhile, the accumulation of huge amounts of data can be used to support intelligent decisions for better lives. Therefore, smart cities are data-driven. But effective computing, like distributed and parallel computing, artificial intelligence, and cloud/fog computing are the basic infrastructure for data processing, especially big data processing, and are the key factors for success in future smart cities. The use of big data can certainly help in creating cities where infrastructure and resources are used in a more efficient manner. The articles in this special section explore emerging trends, issues, and challenges in big data and its implementation toward future smart cities.
Autors: Guangjie Han;Mohsen Guizani;Jaime Lloret;Sammy Chan;Liangtian Wan;Wael Guibene;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2018, volume: 56, issue:2, pages: 76 - 77
Publisher: IEEE
 
» Empirical Distribution of Nearest-Transmitter Distance in Wireless Networks Modeled by Matérn Hard Core Point Processes
Abstract:
Availability of the distribution of the distance between a generic location and the closest point to it from a point process is very crucial for the performance analysis of wireless networks modeled by such a point process. In this paper, we fit the empirical probability density function of the closest-point distance in the Matérn hard core point process of Type II to various existing distributions, and find that the Weibull distribution has the best goodness-of-fit among all other distributions examined (e.g., the gamma, log-normal and Rayleigh distributions). We also propose a better piecewise probability density function for the closest-point distance, including an exact expression and a heuristic formula that can be fitted by a Weibull-like function. Simulation results show that the proposed piecewise model has a very close goodness-of-fit to the empirical data.
Autors: Chunlin Chen;Robert C. Elliott;Witold A. Krzymień;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2018, volume: 67, issue:2, pages: 1740 - 1749
Publisher: IEEE
 
» Empirical Model for Electrical Activation of Aluminum- and Boron-Implanted Silicon Carbide
Abstract:
Accurate modeling of the electrical properties of impurities in semiconductors is essential for the mandatory support of the development of novel semiconductor devices by means of simulations. An appropriate modeling approach to determine the activation rate of dopants in silicon carbide is currently not available, which limits the predictability of process simulations. To remedy this fact, we propose an empirical model for the electrical activation of aluminum and boron impurities in silicon carbide for various annealing temperatures and total doping concentrations. The differences of the two acceptor-type dopants are discussed according to the model predictions and the activation ratios for various processing parameters are presented. The model was implemented into Silvaco’s simulation platform Victory Process and evaluated with respect to published experimental findings.
Autors: Vito Šimonka;Andreas Hössinger;Josef Weinbub;Siegfried Selberherr;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 674 - 679
Publisher: IEEE
 
» Employing DC Transmission in Long Distance AC Motor Drives: Analysis of the Copper Economy and Power Losses Reduction in Mining Facilities
Abstract:
High-frequency problems related to pulse-width modulation motor drive systems with long cables are widely discussed in the literature and very harmful to the system components, resulting in motor insulation failures, bearing damage, and electromagnetic interference, among others. As a solution, in a previous work, an alternative system configuration was proposed in which the rectifier and the inverter are separated through a long dc cable, the inverter being located at the motor terminals. Thus, besides the mitigation of all these problems, the proposed topology also features the additional benefit of reducing the cable power losses and the amount of copper required for the power transmission. In this context, this paper evaluates the copper economy obtained through this alternative drive configuration and presents a case study involving real motor drive systems situated in mining plants, whose actual cost of the cables is compared with that of the alternative configuration.
Autors: Vinicius Cardoso de Paula;Hélder de Paula;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2018, volume: 54, issue:1, pages: 841 - 847
Publisher: IEEE
 
» Enabling a Nationwide Radio Frequency Inventory Using the Spectrum Observatory
Abstract:
Knowledge about active radio transmitters is critical for multiple applications: spectrum regulators can use this information to assign spectrum, licensees can identify spectrum usage patterns and provision their future needs, and dynamic spectrum access applications can efficiently pick operating frequency. To achieve these goals, we need a system that continuously senses and characterizes the radio spectrum. Current measurement systems, however, do not scale over time, frequency and space and cannot perform transmitter detection. We address these challenges with the Spectrum Observatory, an end-to-end system for spectrum measurement and characterization. This paper details the design and integration of the Spectrum Observatory, and describes and evaluates the first unsupervised method for detailed characterization of arbitrary transmitters called TxMiner. We evaluate TxMiner on real-world spectrum measurements collected by the Spectrum Observatory between 30 MHz and 6 GHz and show that it identifies transmitters robustly. Furthermore, we demonstrate the Spectrum Observatory’s capabilities to map the number of active transmitters and their frequency and temporal characteristics, to detect rogue transmitters, and identify opportunities for dynamic spectrum access.
Autors: Mariya Zhivkova Zheleva;Ranveer Chandra;Aakanksha Chowdhery;Paul Garnett;Anoop Gupta;Ashish Kapoor;Matt Valerio;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Feb 2018, volume: 17, issue:2, pages: 362 - 375
Publisher: IEEE
 
» Enabling Cognitive Smart Cities Using Big Data and Machine Learning: Approaches and Challenges
Abstract:
The development of smart cities and their fast-paced deployment is resulting in the generation of large quantities of data at unprecedented rates. Unfortunately, most of the generated data is wasted without extracting potentially useful information and knowledge because of the lack of established mechanisms and standards that benefit from the availability of such data. Moreover, the highly dynamic nature of smart cities calls for a new generation of machine learning approaches that are flexible and adaptable to cope with the dynamicity of data to perform analytics and learn from real-time data. In this article, we shed light on the challenge of underutilizing the big data generated by smart cities from a machine learning perspective. In particular, we present the phenomenon of wasting unlabeled data. We argue that semi-supervision is a must for smart cities to address this challenge. We also propose a three-level learning framework for smart cities that matches the hierarchical nature of big data generated by smart cities with a goal of providing different levels of knowledge abstraction. The proposed framework is scalable to meet the needs of smart city services. Fundamentally, the framework benefits from semi-supervised deep reinforcement learning where a small amount of data that has users' feedback serves as labeled data, while a larger amount without such users' feedback serves as unlabeled data. The framework utilizes a mix of labeled and unlabeled data to converge toward better control policies instead of wasting the unlabeled data. This article also explores how deep reinforcement learning and its shift toward semi-supervision can handle the cognitive side of smart city services and improve their performance by providing several use cases spanning the different domains of smart cities. We also highlight several challenges as well as promising future research directions for incorporating machine learning and high-level intelligence into smart city services.
Autors: Mehdi Mohammadi;Ala Al-Fuqaha;
Appeared in: IEEE Communications Magazine
Publication date: Feb 2018, volume: 56, issue:2, pages: 94 - 101
Publisher: IEEE
 
» Endocardial Energy Harvesting by Electromagnetic Induction
Abstract:
Objective: cardiac pacemakers require regular medical follow-ups to ensure proper functioning. However, device replacements due to battery depletion are common and account for ∼25% of all implantation procedures. Furthermore, conventional pacemakers require pacemaker leads which are prone to fractures, dislocations or isolation defects. The ensuing surgical interventions increase risks for the patients and costs that need to be avoided. Methods: in this study, we present a method to harvest energy from endocardial heart motions. We developed a novel generator, which converts the heart's mechanical into electrical energy by electromagnetic induction. A mathematical model has been introduced to identify design parameters strongly related to the energy conversion efficiency of heart motions and fit the geometrical constraints for a miniaturized transcatheter deployable device. The implemented final design was tested on the bench and in vivo. Results : the mathematical model proved an accurate method to estimate the harvested energy. For three previously recorded heart motions, the model predicted a mean output power of 14.5, 41.9, and 16.9 μW. During an animal experiment, the implanted device harvested a mean output power of 0.78 and 1.7 μW at a heart rate of 84 and 160 bpm, respectively. Conclusion: harvesting kinetic energy from endocardial motions seems feasible. Implanted at an energetically favorable location, such systems might become a welcome alternative to extend the lifetime of cardiac implantable electronic device. Significance: the presented endocardial energy harvesting concept has the potential to turn pacemakers into battery- and leadless systems and thereby eliminate two major drawbacks of contemporary systems.
Autors: Adrian Zurbuchen;Andreas Haeberlin;Lukas Bereuter;Alois Pfenniger;Simon Bosshard;Micha Kernen;Paul Philipp Heinisch;Juerg Fuhrer;Rolf Vogel;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2018, volume: 65, issue:2, pages: 424 - 430
Publisher: IEEE
 
» Ends and Means
Abstract:
Even the smallest coding mistake can cause huge problems when it slips by testing. Finding it can be difficult, and retesting the fixed system can be expensive, but this certainly isn't true for every type of problem. A defect found and fixed during coding is a fairly routine occurrence and not costlier than a defect found and fixed during design. Quite the opposite is usually true.
Autors: Gerard J. Holzmann;
Appeared in: IEEE Software
Publication date: Feb 2018, volume: 35, issue:1, pages: 14 - 17
Publisher: IEEE
 
» Energy Consumption Enhancement of Reverse-Biased Silicon-Based Mach–Zehnder Modulators Using Corrugated Slow Light Waveguides
Abstract:
The energy efficiency of silicon modulators can be enhanced by increasing the doping level. As an alternative solution, slow light modulators based on corrugated waveguides can also be used for improving the energy efficiency. Using numerical and analytical tools, we show that for the same level of energy consumption reduction, the loss coefficient and the loss-modulation efficiency for the slow-light modulators are smaller than those for the modulators with an increased doping level. It is shown that the slow light structures with medium slow down factors (specifically slowdown factors of less than 6) can be reasonable candidates for enhancing the modulator's energy efficiency. For example, an energy consumption of less than 100 fJ/bit can be achieved at a slow-down factor of 6, using a doping level of 5 × 1017 cm-3 for acceptors and 1 × 1018 cm-3 for donors.
Autors: Reza Hosseini;Levon Mirzoyan;Kambiz Jamshidi;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 7
Publisher: IEEE
 
» Energy Efficiency in Cache-Enabled Small Cell Networks With Adaptive User Clustering
Abstract:
Using a network of cache enabled small cells, traffic during peak hours can be reduced by proactively fetching the content that is most likely to be requested. In this paper, we aim to explore the impact of proactive caching on an important metric for future generation networks, namely, energy efficiency (EE). We argue that, exploiting the spatial repartitions of users in addition to the correlation in their content popularity profiles, can result in considerable improvement of the achievable EE. In this paper, the optimization of EE is decoupled into two related subproblems. The first one addresses the issue of content popularity modeling. While most existing works assume similar popularity profiles for all users, we consider an alternative framework in which, users are clustered according to their popularity profiles. In order to showcase the utility of the proposed clustering, we use a statistical model selection criterion, namely, Akaike information criterion. Using stochastic geometry, we derive a closed-form expression of the achievable EE and we find the optimal active small cell density vector that maximizes it. The second subproblem investigates the impact of exploiting the spatial repartitions of users. After considering a snapshot of the network, we formulate a combinatorial problem that optimizes content placement in order to minimize the transmission power. Numerical results show that the clustering scheme considerably improves the cache hit probability and consequently the EE, compared with an unclustered approach. Simulations also show that the small base station allocation algorithm improves the energy efficiency and hit probability.
Autors: Salah Eddine Hajri;Mohamad Assaad;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 955 - 968
Publisher: IEEE
 
» Energy-Efficient and Distributed Network Management Cost Minimization in Opportunistic Wireless Body Area Networks
Abstract:
Mobility induced by limb/body movements in Wireless Body Area Networks (WBANs) significantly affects the link-quality of intra-BAN and inter-BAN communication units, which, in turn, affects the Quality-of-Service (QoS) of each WBAN, in terms of reliability, efficient data transmission and network throughput guarantees. Further, the variation in link-quality between WBANs and Access Points (APs) makes the WBAN-equipped patients more resource-constrained in nature, which also increases the data dissemination delay. Therefore, to minimize the data dissemination delay of the network, WBANs send patients’ physiological data to local servers using the proposed opportunistic transient connectivity establishment algorithm. Additionally, limb/body movements induce dynamic changes to the on-body network topology, which, in turn, increases the network management cost and decreases the life-time of the sensor nodes periodically. Also, mutual and cross technology interference among coexisting WBANs and other radio technologies increases the energy consumption rate of the sensor nodes and also the energy management cost. To address the problem of increased network management cost and data dissemination delay, we propose a network management cost minimization framework to optimize the network throughput and QoS of each WBAN. The proposed framework attempts to minimize the dynamic connectivity, interference management, and data dissemination costs for opportunistic WBAN. We have, theoretically, analyzed the performance of the proposed framework to provide reliable data transmission in opportunistic WBANs. Simulation results show significant improvement in the network performance compared to the existing solutions.
Autors: Amit Samanta;Sudip Misra;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Feb 2018, volume: 17, issue:2, pages: 376 - 389
Publisher: IEEE
 
» Energy-efficient fast configuration of flexible transponders and grooming switches in OFDM-based elastic optical networks
Abstract:
We investigate the problem of energy-efficient resource allocation constrained to quality of service and physical requirements in orthogonal frequency division multiplexing (OFDM)-based elastic optical networks and propose a fast two-stage algorithm to solve it. The first stage of the proposed algorithm deals with routing, traffic grooming, and traffic ordering and mainly aims at minimization of the number of deployed optical amplifiers and transponders. We provide an integer linear program for routing and traffic grooming and propose a heuristic procedure, which yields its near-optimum solution in a shorter runtime. In the second stage, we optimize transponder parameters to minimize total transponder power consumption. We show how signal-to-noise ratio and transponder power consumption are represented by convex expressions and use the results to provide a convex formulation for optimizing transponder parameters. Unlike the conventional formulations, we consider transmitted optical power as an optimization variable tuned for each lightpath and show how this improves power consumption of different network elements. Simulation results demonstrate that the proposed algorithm for routing and traffic grooming is around 2 orders of magnitude faster than its equivalent integer linear formulation and reduces network power consumption more than 9% compared with the scenario in which no traffic grooming is applied. It is also shown that our convex formulation for transponder parameter assignment is 1 order of magnitude faster than its mixed-integer nonlinear counterpart and reduces total transponder power consumption more than 13% compared with a fixed transponder configuration scheme. Furthermore, we investigate the effect of adaptive modulation assignment on power consumption and show it is not necessary to have complex transponders supporting a high number of modulation formats. We also analyze the impact of transponder capacity on traffic grooming and investigate the inh- rent trade-off between capital expenditures and operational expenditures in terms of the capacity and design complexity of the transponders.
Autors: Mohammad Hadi;Mohammad Reza Pakravan;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Feb 2018, volume: 10, issue:2, pages: 90 - 103
Publisher: IEEE
 
» Energy-Efficient Sensor Data Collection Approach for Industrial Process Monitoring
Abstract:
The use of wireless sensor network for industrial applications has attracted much attention from both academic and industrial sectors. It enables a continuous monitoring, controlling, and analyzing of the industrial processes, and contributes significantly to finding the best performance of operations. Sensors are typically deployed to gather data from the industrial environment and to transmit it periodically to the end user. Since the sensors are resource constrained, effective energy management should include new data collection techniques for an efficient utilization of the sensors. In this paper, we propose adaptive data collection mechanisms that allow each sensor node to adjust its sampling rate to the variation of its environment, while at the same time optimizing its energy consumption. We provide and compare three different data collection techniques. The first one uses the analysis of data variances via statistical tests to adapt the sampling rate, whereas the second one is based on the set-similarity functions, and the third one on the distance functions. Both simulation and real experimentations on telosB motes were performed in order to evaluate the performance of our techniques. The obtained results proved that our proposed adaptive data collection methods can reduce the number of acquired samples up to 80% with respect to a traditional fixed-rate technique. Furthermore, our experimental results showed significant energy savings and high accurate data collection compared to existing approaches.
Autors: Hassan Harb;Abdallah Makhoul;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2018, volume: 14, issue:2, pages: 661 - 672
Publisher: IEEE
 
» Engineering the Structural Nonlinearity Using Multimodal-Shaped Springs in MEMS
Abstract:
The purpose of this paper is to introduce a novel technique to engineer in a precise way the structural nonlinearity in MEMS springs. To perform the adjustment of structural nonlinearity, the idea of using a sine-shaped beam following the combination of the natural bending modes of a straight one is explored to create a multimodal-shaped spring. The basic analytical model of multimodal beam bending is introduced and validated with finite element modeling. Proposed multimodal springs are fabricated by deep reactive ion etching on silicon on insulator wafer and their force-displacement characteristics are extracted using a force probe, with the resulting curves being close to the ones predicted by the theoretical calculations. The presented spring allows the engineering of structural nonlinearity by varying the amplitudes of the different modes used as initial shape. Thus, a straightforward method to create any type of structural nonlinearity starting from fully bistable up to the linear case, without the need to combine springs of several types, reducing the complexity of the targeted systems and their footprint. The proposed methodology was used to successfully design a suspension spring that exhibits flat force-displacement region with the aim to increase the bandwidth of vibrational energy harvesters. [2017-0250]
Autors: Bogdan Vysotskyi;Fabien Parrain;Denis Aubry;Philippe Gaucher;Xavier Le Roux;Elie Lefeuvre;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Feb 2018, volume: 27, issue:1, pages: 40 - 46
Publisher: IEEE
 
» Enhance In-Hand Dexterous Micromanipulation by Exploiting Adhesion Forces
Abstract:
Micromanipulation plays a key role in the development of complex and assembled microsystems. However, current micromanipulation solutions are often limited to small rotation amplitudes and to simple shaped objects (such as cubes). Our approach consists of developing in-hand micromanipulation techniques using dexterous microhands to manipulate arbitrary shaped objects and to perform large rotations. This paper focuses on the trajectory generation of a dexterous microhand to achieve automated repositioning by taking advantage of adhesion forces. The results on the generated trajectories show that adhesion forces can be exploited to enhance the manipulation possibilities. Moreover, experiments show that planed rotations are performed at more than using an open-loop control. Dexterous micromanipulation is a promising way to perform complex manipulation tasks in microscale.
Autors: Jean-Antoine Seon;Redwan Dahmouche;Michaël Gauthier;
Appeared in: IEEE Transactions on Robotics
Publication date: Feb 2018, volume: 34, issue:1, pages: 113 - 125
Publisher: IEEE
 
» Enhanced Coherent BOTDA System Without Trace Averaging
Abstract:
We propose and experimentally demonstrate a scheme of a coherent Brillouin time domain analysis (BOTDA) system without any trace averaging. Assisted by a commercial integrated coherent receiver with a local oscillator generated through single sideband modulation from the same laser source, the Brillouin signals carried on a stable intermediate frequency (IF) are extracted by electrical/digital filters and then recovered to baseband by digital signal processing. This increases the signal-to-noise ratio and avoids the need of trace averaging and enables real-time signal acquisition. To eliminate the Brillouin gain fluctuation, two adjacent Brillouin time-domain traces stimulated by two sequential orthogonal pump pulses are recovered after the IF signals are detected in a real-time manner. Based on this configuration, a spatial resolution of 4 m and Brillouin frequency shift uncertainty of 1.473 MHz are realized in distributed temperature sensing over 40.63 km range. With the nonlocal means algorithm and distributed Raman amplification integrated into the system, the BFS uncertainty is enhanced to 0.843 MHz and better spatial resolution of 2 m over the same sensing fiber is achieved.
Autors: Nan Guo;Liang Wang;Huan Wu;Chao Jin;Hwa-Yaw Tam;Chao Lu;
Appeared in: Journal of Lightwave Technology
Publication date: Feb 2018, volume: 36, issue:4, pages: 871 - 878
Publisher: IEEE
 
» Enhanced Electrical Performance and Negative Bias Illumination Stability of Solution-Processed InZnO Thin-Film Transistor by Boron Addition
Abstract:
In this paper, boron-doped indium–zinc–oxide (InZnO) thin-film transistors (BIZO TFTs) were fabricated by solution process. The electrical performance and stability under the negative bias illumination stress (NBIS) have been greatly improved by B doping. The BIZO TFT with 5 mol.% B doping ratio shows a superior electrical performance with a field-effect mobility of 10.15 cm2/, a threshold voltage of 3.29 V, a subthreshold swing of 0.35 V/decade, and an ON/OFF ratio of 108. Furthermore, the 5 mol.% BIZO TFT shows only a −1.59 V shift of the threshold voltage, compared with a large negative shift of −4.24 V for pure IZO TFTs. The enhancement of electrical performance and stability under NBIS is due to the reduction of oxygen vacancies, which are suppressed by B doping. The density of states is calculated to further validate the improved electrical performance and NBIS stability of BIZO TFTs.
Autors: De-Yao Zhong;Jun Li;Cheng-Yu Zhao;Chuan-Xin Huang;Jiang-Hua Zhang;Xi-Feng Li;Xue-Yin Jiang;Zhi-Lin Zhang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 520 - 525
Publisher: IEEE
 
» Enhanced Hydrated Lime—A Simple Solution for Acid Gas Compliance
Abstract:
The U.S. landscape of environmental regulations is complex and continues to evolve requiring more stringent acid gas emission limits than ever. Current regulations include acid gas emission requirements via the Portland Cement National Emission Standard for Hazardous Air Pollutants, consent decrees, and revised operating permits, where operational modifications are made requiring additional acid gas removal. As a result of the need to comply with these increasingly stringent acid gas emission limits, there is a growing desire for a relatively simple solution. Dry sorbent injection (DSI) technology offers a low capital cost solution with a relatively small equipment footprint, low power consumption, and ease of retrofit to a majority of existing facilities. As DSI technology has matured, the systems have become more reliable and advancements in calcium based sorbents have provided new compliance solutions that were not available in past years. The optimization of the physical properties of enhanced hydrated lime products has demonstrated upward of 90% sulfur dioxide and 95+% hydrochloric acid reduction with the DSI technology over a range of applications, and has been consistently successful achieving cement plant's acid gas removal needs to meet their regulatory requirements.
Autors: Gerald Hunt;Johan J. Heiszwolf;Melissa Sewell;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2018, volume: 54, issue:1, pages: 796 - 807
Publisher: IEEE
 
» Enhanced Model and Real-Time Simulation Architecture for Modular Multilevel Converter
Abstract:
This paper presents i) an equivalent model of the half-bridge modular multilevel converter (HB-MMC) which is suitable for real-time applications, ii) a hybrid central-processing unit/field-programmable gate array (CPU/FPGA)-based architecture for real-time simulation of electromagnetic transients of systems which include HB-MMC, and iii) a novel arrangement for sorting results referred to as the “sub-module (SM) rank list”, which tackles the bottleneck for parallel implementation of the MMC arm model solver on the FPGA. The Adam–Bashforth (AB) method is used for numerical integration of the HB-SM capacitor model. The second-order AB method provides a constant admittance matrix of the HB-MMC and, thus, reduces computational burden while offering the same accuracy as that of the widely used Trapezoidal method. The CPU/FPGA-based architecture is optimized to obtain maximum parallelism of the HB-MMC model implementation, adopting a standard, single-precision, floating-point computational engine. The proposed sorting arrangement is independent of the utilized sorting algorithm and its application to the odd–even bubble sorting scheme is presented in this paper. The proposed architecture offers a simulation time-step of 825 ns while including the sorting module as the SM capacitor voltage-balancing control unit. This enables accurate analysis of MMC controls based on either software-in-the-loop or hardware-in-the-loop approaches. Performance and accuracy of the MMC model and the hybrid CPU/FPGA-based architecture are evaluated based on a set of case studies on a 401-level HB-MMC-based HVDC station and verified based on offline simulation results in the PSCAD/EMTDC environment.
Autors: Mojtaba Ashourloo;Ramin Mirzahosseini;Reza Iravani;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2018, volume: 33, issue:1, pages: 466 - 476
Publisher: IEEE
 
» Enhancement of a Continuous Liquid Level Sensor Based on a Macro-Bend Polymer Optical Fiber Coupler
Abstract:
An approach to improve the side-coupling ratio of the macro-bend polymer optical fiber (POF) coupler is proposed in this paper. Two naked POFs are twisted and twined around a cylinder to achieve continuous liquid level sensing. Through filling the gap between the two twisted POFs with UV optical cement, both the sensitivity and the measurement range are increased substantially. The reversibility is also improved since the gap is eliminated, and little liquid can exist in the structure with the liquid level decreasing. The design turns out to be a good method to enhance the performance, and could also be applied in the displacement or stress sensing field.
Autors: Yingzi Zhang;Yulong Hou;Yanjun Zhang;Yanjun Hu;Liang Zhang;Xiaolong Gao;Huixin Zhang;Wenyi Liu;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 6
Publisher: IEEE
 
» Enhancement of Intercellular Electrical Synchronization by Conductive Materials in Cardiac Tissue Engineering
Abstract:
Objective: cardiac tissue regeneration for the treatment of cardiovascular diseases has been of great research interest. Under the hypothesis that electrical synchronization of cardiac cells can be aided by conductive materials, electrically conductive scaffolds have been frequently used to improve cardiac tissue regeneration. However, theoretical analysis is presently absent in examining the underlying mechanism and rationally guiding the design of these conductive scaffolds. Methods: here, equivalent-circuit models are proposed, in which two adjacent groups of cardiomyocytes are grown either on a bulk conductive substrate or around conductive nanostructures. When one group of cells leads with action potentials, the membrane depolarization of the following group is investigated. Results: this study reveals that membrane depolarization of the following group is most sensitive to seal resistance to the substrate while surface roughness and conductivity of the material have less influence. In addition, it is found that a multiple-cell group is easier to be depolarized by its adjacent beating cardiomyocytes. For nanostructure-bridged cardiac cells, substantial depolarization occurs only with a seal resistance larger than 1013 Ω/sqr, which is contradictory to many reported estimations. Conclusion: this work theoretically confirms the positive role of conductive scaffolds and nanostructures in aiding electrical synchronization of cardiac cells and reveals that its performance mainly relies on the cell-device interface. Significance: this work provides a theoretical basis for the rational design of electroactive scaffolds for enhanced cardiac tissue engineering.
Autors: Yu Wu;Liang Guo;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Feb 2018, volume: 65, issue:2, pages: 264 - 272
Publisher: IEEE
 
» Enhancing Selectivity in Big Data
Abstract:
Today’s companies collect immense amounts of personal data and enable wide access to it within the company. This exposes the data to external hackers and privacy-transgressing employees. This study shows that, for a wide and important class of workloads, only a fraction of the data is needed to approach state-of-the-art accuracy. We propose selective data systems that are designed to pinpoint the data that is valuable for a company’s current and evolving workloads. These systems limit data exposure by setting aside the data that is not truly valuable.
Autors: Mathias Lecuyer;Riley Spahn;Roxana Geambasu;Tzu-Kuo Huang;Siddhartha Sen;
Appeared in: IEEE Security & Privacy
Publication date: Feb 2018, volume: 16, issue:1, pages: 34 - 42
Publisher: IEEE
 
» Enhancing the Student Learning Experience in Software Engineering Project Courses
Abstract:
Carrying out real-world software projects in their academic studies helps students to understand what they will face in industry, and to experience first-hand the challenges involved when working collaboratively. Most of the instructional strategies used to help students take advantage of these activities focus on supporting agile programming, which is appropriate for capstone courses. This is not always recommended in initial software engineering project courses, however, where novice developers run projects in teams while simultaneously taking other courses. To enhance the learning and teamwork experience in this latter instructional scenario, this paper proposes a formative monitoring method, reflexive weekly monitoring (RWM), for use in project courses that involve disciplined software processes and loosely coupled work. RWM uses self-reflection and collaborative learning practices to help students be aware of their individual and team performance. RWM was applied in a case study over nine consecutive semesters. The results obtained indicate that RWM was effective in enhancing the learning experience in the instructional scenario studied. While students in the monitored teams were more effective and coordinated, and experienced a higher sense of team belonging and satisfaction, little evidence was found of them being more productive than students working in non-monitored teams.
Autors: Maíra Marques;Sergio F. Ochoa;María Cecilia Bastarrica;Francisco J. Gutierrez;
Appeared in: IEEE Transactions on Education
Publication date: Feb 2018, volume: 61, issue:1, pages: 63 - 73
Publisher: IEEE
 
» Ensemble of ESA/AATSR Aerosol Optical Depth Products Based on the Likelihood Estimate Method With Uncertainties
Abstract:
Within the European Space Agency Climate Change Initiative (CCI) project Aerosol_cci, there are three aerosol optical depth (AOD) data sets of Advanced Along-Track Scanning Radiometer (AATSR) data. These are obtained using the ATSR-2/ATSR dual-view aerosol retrieval algorithm (ADV) by the Finnish Meteorological Institute, the Oxford-Rutherford Appleton Laboratory (RAL) Retrieval of Aerosol and Cloud (ORAC) algorithm by the University of Oxford/RAL, and the Swansea algorithm (SU) by the University of Swansea. The three AOD data sets vary widely. Each has unique characteristics: the spatial coverage of ORAC is greater, but the accuracy of ADV and SU is higher, so none is significantly better than the others, and each has shortcomings that limit the scope of its application. To address this, we propose a method for converging these three products to create a single data set with higher spatial coverage and better accuracy. The fusion algorithm consists of three parts: the first part is to remove the systematic errors; the second part is to calculate the uncertainty and fusion of data sets using the maximum likelihood estimate method; and the third part is to mask outliers with a threshold of 0.12. The ensemble AOD results show that the spatial coverage of fused data set after mask is 148%, 13%, and 181% higher than those of ADV, ORAC, and SU, respectively, and the root-mean-square error, mean absolute error, mean bias error, and relative mean bias are superior to those of the three original data sets. Thus, the accuracy and spatial coverage of the fused AOD data set masked with a threshold of 0.12 are improved compared to the original data set. Finally, we discuss the selection of mask thresholds.
Autors: Yanqing Xie;Yong Xue;Yahui Che;Jie Guang;Linlu Mei;Dave Voorhis;Cheng Fan;Lu She;Hui Xu;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Feb 2018, volume: 56, issue:2, pages: 997 - 1007
Publisher: IEEE
 
» Equilibriums in the Mobile-Virtual-Network-Operator-Oriented Data Offloading
Abstract:
Cellular networks are now facing severe traffic overload problems due to the explosive growth of mobile data traffic. One of the promising solutions is to offload part of the traffic through WiFi. In this paper, we investigate an oligopoly offloading market, where several mobile virtual network operators (MVNOs) compete to serve end users using network infrastructures leased from the host mobile network operator (MNO). First, we study the competitive interaction among multiple MVNOs considering the overload problems of the offloading market. Then, we formulate the interaction as a noncooperative inventory game, where each MVNO determines the amount of cellular traffic provided to end users (named as the traffic inventory). Particularly, we investigate two different behavior patterns of the MVNOs known as Cournot and Stackelberg models. Then, we analyze and derive the existence and uniqueness of the equilibrium in each inventory game. Furthermore, algorithms are designed to achieve the equilibriums. Based on these analyses, we find the optimal inventory strategy for these competing MVNOs. Finally, simulation results demonstrate the interactions among the MNO, MVNOs, and end users in the offloading market.
Autors: Fei Sun;Fen Hou;Haibo Zhou;Bo Liu;Jiacheng Chen;Lin Gui;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2018, volume: 67, issue:2, pages: 1622 - 1634
Publisher: IEEE
 
» Equivalent Circuit of the Neuro-Electronic Junction for Signal Recordings From Planar and Engulfed Micro-Nano-Electrodes
Abstract:
In the latest years, several attempts to develop extracellular microtransducers to record electrophysiological activity of excitable cells have been done. In particular, many efforts have been oriented to increase the coupling conditions, and, thus, improving the quality of the recorded signal. Gold mushroom-shaped microelectrodes (GMμE) are an example of nano-devices to achieve those requirements. In this study, we developed an equivalent electrical circuit of the neuron–microelectrode system interface to simulate signal recordings from both planar and engulfed micro-nano-electrodes. To this purpose, models of the neuron, planar, gold planar microelectrode, and GMμE, neuro-electronic junction (microelectrode–electrolyte interface, cleft effect, and protein-glycocalyx electric double layer) are presented. Then, neuronal electrical activity is simulated by Hspice software, and analyzed as a function of the most sensitive biophysical models parameters, such as the neuron–microelectrode cleft width, spreading and seal resistances, ion-channel densities, double-layer properties, and microelectrode geometries. Results are referenced to the experimentally recorded electrophysiological neuronal signals reported in the literature.
Autors: Giuseppe Massobrio;Sergio Martinoia;Paolo Massobrio;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Feb 2018, volume: 12, issue:1, pages: 3 - 12
Publisher: IEEE
 
» Ergodic Rate of Millimeter Wave Ad Hoc Networks
Abstract:
In this paper, we use a stochastic geometry approach to quantify the ergodic rate of each user in an outdoor mm-wave ad hoc network. For a variety of use cases, it is reasonable to assume users will be clustered around a central point (e.g., WiFi hotspot or clusterhead) rather than uniformly distributed. Our results indicate that, in contrast to sub-6-GHz networks, clustered mm-wave ad hoc networks tolerate the increased interference because directional antenna arrays reduce the interference. For certain antenna array configurations and user densities, uncoordinated users within a cluster outperform TDMA. Additionally, we derive a scaling law for uniform mm-wave ad hoc networks and propose a heuristic scaling for clustered networks. The per user ergodic rate remains constant if mm-wave antenna arrays scale sub-linearly with the number of users for uniform networks or linearly in clustered networks as users are added to the cluster. Last, we compute expressions that quantify the loss in ergodic rate per user when alignment error occurs at the receiver and transmitter. Our results show that even relatively small errors in alignment can lead to significant ergodic rate reduction.
Autors: Andrew Thornburg;Robert W. Heath;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 914 - 926
Publisher: IEEE
 
» Estimating the specific heat capacity and heating of electronic sensors and devices
Abstract:
Most sensors have three functional parts: the sensor part, signal conditioning part and interface part (Fig. 1). The sensor part senses the physical phenomena and transforms it typically into electric form. The signal condition part amplifies, linearizes and scales the electric signal. The interface part can be a simple mechanical connector, (field) bus adapter or in a wireless sensor, a radio module. Signal conditioning and interface parts are in most cases implemented by electronics.
Autors: Ilkka Korhonen;Jero Ahola;
Appeared in: IEEE Instrumentation & Measurement Magazine
Publication date: Feb 2018, volume: 21, issue:1, pages: 54 - 62
Publisher: IEEE
 
» Evaluation of DC Collector-Grid Configurations for Large Photovoltaic Parks
Abstract:
This paper presents a detailed comparison between the conventional ac collector-grid configuration and two proposed dc collector-grid configurations for large photovoltaic (PV) parks. One complete year of measured weather data at two different locations, one very sunny and the other with relatively less sun, is used for the evaluation. An already validated PV performance model is used to estimate the expected energy yield of the PV park for the given environmental and connection conditions. Loss mechanisms in different grid components in the three configurations are discussed based on the developed models. These components include the inverters, transformers, cables, and dc–dc converters. A comparison of the total losses in these components helps to identify the configuration that has the potential to operate at higher efficiency and, hence, generate maximum revenue. The economic viability metrics are calculated and a sensitivity analysis is carried out using the Monte Carlo method with a uncertainty in the considered cost and energy yield parameters.
Autors: Hafiz Abu Bakar Siddique;Rik W. De Doncker;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2018, volume: 33, issue:1, pages: 311 - 320
Publisher: IEEE
 
» Evaluation of Local Error Estimators for the RWG-Based EFIE
Abstract:
Several error estimators suitable for use with the adaptive refinement solution of the electric field integral equation (EFIE) are investigated. The estimators are evaluated using a series of test problems for which correlation coefficients and scatter plots are computed. In addition, two new discontinuity estimators are introduced based on the combination of the charge discontinuity with the current or current discontinuity. The evaluations show that simple discontinuity estimators are as accurate for adaptive refinement as the EFIE residual estimator, and are far more computationally efficient.
Autors: Sang Kyu Kim;Andrew F. Peterson;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2018, volume: 66, issue:2, pages: 819 - 826
Publisher: IEEE
 
» Evaluation of Parallel Level Sets and Bowsher’s Method as Segmentation-Free Anatomical Priors for Time-of-Flight PET Reconstruction
Abstract:
In this article, we evaluate Parallel Level Sets (PLS) and Bowsher’s method as segmentation-free anatomical priors for regularized brain positron emission tomography (PET) reconstruction. We derive the proximity operators for two PLS priors and use the EM-TV algorithm in combination with the first order primal-dual algorithm by Chambolle and Pock to solve the non-smooth optimization problem for PET reconstruction with PLS regularization. In addition, we compare the performance of two PLS versions against the symmetric and asymmetric Bowsher priors with quadratic and relative difference penalty function. For this aim, we first evaluate reconstructions of 30 noise realizations of simulated PET data derived from a real hybrid positron emission tomography/magnetic resonance imaging (PET/MR) acquisition in terms of regional bias and noise. Second, we evaluate reconstructions of a real brain PET/MR data set acquired on a GE Signa time-of-flight PET/MR in a similar way. The reconstructions of simulated and real 3D PET/MR data show that all priors were superior to post-smoothed maximum likelihood expectation maximization with ordered subsets (OSEM) in terms of bias-noise characteristics in different regions of interest where the PET uptake follows anatomical boundaries. Our implementation of the asymmetric Bowsher prior showed slightly superior performance compared with the two versions of PLS and the symmetric Bowsher prior. At very high regularization weights, all investigated anatomical priors suffer from the transfer of non-shared gradients.
Autors: Georg Schramm;Martin Holler;Ahmadreza Rezaei;Kathleen Vunckx;Florian Knoll;Kristian Bredies;Fernando Boada;Johan Nuyts;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Feb 2018, volume: 37, issue:2, pages: 590 - 603
Publisher: IEEE
 
» Evaluation of the Potential of Dipole Field Navigation for the Targeted Delivery of Therapeutic Agents in a Human Vascular Network
Abstract:
Magnetically guided agents in the vascular network are expected to enable the targeted delivery of therapeutics to localized regions while avoiding their systemic circulation. Due to the small size of the medically applicable superparamagnetic microscale agents required to reach the smaller arteries, high magnetic fields and gradients are required to reach saturation magnetization and generate sufficient directional forces, respectively, for their effective navigation in the vascular environment. Currently, the only method that provides both a high field and high magnetic gradient strengths in deep tissues at the human scale is known as dipole field navigation (DFN). This method relies on the controlled distortion of the field inside a magnetic resonance imaging scanner by precisely positioning ferromagnetic cores around the patient. This paper builds on previous works that have experimentally demonstrated the feasibility of the method and proposed optimization algorithms for placing the cores. The maximum gradient strengths that can be generated for single and multibifurcation vascular routes are investigated while considering the major constraints on core positions (limited space in the scanner, magnetic interactions). Using disc cores, which were previously shown particularly effective for the DFN, results show that gradient strengths exceeding 400 mT/m (a tenfold increase with respect to typical gradients generated by clinical MRI scanners) can be achieved at 10 cm inside the patient, but decrease as the complexity of the vascular route increases. The potential of the method is evaluated for targeting regions of a vascular model of a human liver, segmented from clinical data, with encouraging results showing strengths up to 150 mT/m for generating gradients at three consecutive bifurcations within 20° of average gradient direction error.
Autors: Maxime Latulippe;Sylvain Martel;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2018, volume: 54, issue:2, pages: 1 - 12
Publisher: IEEE
 
» Evaluation of the Role of Deep Trap State Using Analytical Model in the Program/Erase Cycling of NAND Flash Memory and Its Process Dependence
Abstract:
A method to analyze the kinetics of the charge accumulation in the tunnel oxide by the nand flash memory program and erase (P/E) cycling is proposed. Both electron trapping and detrapping processes are required to be considered owing to the oxide high electric field during P/E cycles. Consequently, the electron trapping in the deep trap state is concluded, whose trap energy () is more than 3.5 eV. Furthermore, the as-grown trap state density (), the trapping capture cross section (), and the number of trapped positive charges can also be extracted to explain the tunneling current modulation and the shift by oxide-trapped charges under the P/E stress. The trapped electrons are mainly distributed in the center of tunnel oxide, and the distributed area extends as the P/E bias increases. In addition, the dependence of oxidation process is also shown. Both thermal dry and plasma oxidation have almost the same value of ( cm2). However, 30% reduction of is shown in plasma oxidation ( cm−3) when compared with thermal dry oxidation ( cm−3).
Autors: Bo-Jun Yang;Yu-Ting Wu;Yung-Yueh Chiu;Tse-Mien Kuo;Jung-Ho Chang;Pin-Yao Wang;Riichiro Shirota;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 499 - 506
Publisher: IEEE
 
» Evaluations of a Class of Integrals That Arise in Wave Scattering Problems by Using the Taylor Product Theorem
Abstract:
Taylor product theorem is applied to the evaluation of a class of integrals that arise in high-frequency wave scattering problems. We expand a term under the integral into exponentiated powers of that are suitable for term-by-term integrations. We utilize the expansion in an example and make accuracy and speed analysis.
Autors: Ali Uzer;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Feb 2018, volume: 66, issue:2, pages: 1031 - 1034
Publisher: IEEE
 
» Event-Based Model Predictive Tracking Control of Nonholonomic Systems With Coupled Input Constraint and Bounded Disturbances
Abstract:
This paper studies the event-based model predictive control (EMPC) for tracking of nonholonomic mobile robot with coupled input constraint and bounded disturbances. First, an event-triggering mechanism is presented by designing a threshold for the error between the actual trajectory and the predicted one, aiming at reducing the computational load. Second, a model predictive control strategy is developed based on the event-triggering mechanism. Recursive feasibility is guaranteed by designing a robust terminal region and the proper parameters. We show that the tracking system is practically stable and also provides a convergence region for the tracking error. The convergence region indicates that the tracking performance is negatively related to the minimal interevent time as well as the bound of the disturbances. Finally, simulation results show that the computation load is significantly reduced and illustrate the efficiency of our proposed strategy.
Autors: Zhongqi Sun;Li Dai;Yuanqing Xia;Kun Liu;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Feb 2018, volume: 63, issue:2, pages: 608 - 615
Publisher: IEEE
 
» Event-Triggered Protocol for the Consensus of Multi-Agent Systems With State-Dependent Nonlinear Coupling
Abstract:
This paper proposes an event-triggered protocol to achieve consensus in multi-agent system, in which neighboring agents are coupled via a nonlinear function with local passivity. It is mathematically proved that the proposed protocol guarantees average consensus in the system, excluding the existence of Zeno phenomenon. As a practical application, the scheme is applied to achieve synchronization in the Kuramoto oscillator network. Phase agreement is obtained for oscillators with identical natural frequency. For oscillators with non-identical natural frequencies, their phases are confined in a bounded range and their frequencies reach an average of their natural frequencies. To further demonstrate the generality of the scheme, another multi-agent system with coupling based on exponential and tangent functions is also presented. All the simulation results verify the condition of consensus and confirm the effectiveness of the scheme.
Autors: Qiang Jia;Wallace K. S. Tang;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Feb 2018, volume: 65, issue:2, pages: 723 - 732
Publisher: IEEE
 
» Every Timestamp Counts: Accurate Tracking of Network Latencies Using Reconcilable Difference Aggregator
Abstract:
User-facing services deployed in data centers must respond quickly to user actions. The measurement of network latencies is of paramount importance. Recently, a new family of compact data structures has been proposed to estimate one-way latencies. In order to achieve scalability, these new methods rely on timestamp aggregation. Unfortunately, this approach suffers from serious accuracy problems in the presence of packet loss and reordering, given that a single lost or out-of-order packet may invalidate a huge number of aggregated samples. In this paper, we unify the problem to detect lost and reordered packets within the set reconciliation framework. Although the set reconciliation approach and the data structures for aggregating packet timestamps are previously known, the combination of these two principles is novel. We present a space-efficient synopsis called reconcilable difference aggregator (RDA). RDA maximizes the percentage of useful packets for latency measurement by mapping packets to multiple banks and repairing aggregated samples that have been damaged by lost and reordered packets. RDA simultaneously obtains the average and the standard deviation of the latency. We provide a formal guarantee of the performance and derive optimized parameters. We further design and implement a user-space passive latency measurement system that addresses practical issues of integrating RDA into the network stack. Our extensive evaluation shows that compared with existing methods, our approach improves the relative error of the average latency estimation in 10–15 orders of magnitude, and the relative error of the standard deviation in 0.5–6 orders of magnitude.
Autors: Yongquan Fu;Pere Barlet-Ros;Dongsheng Li;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Feb 2018, volume: 26, issue:1, pages: 90 - 103
Publisher: IEEE
 
» Evidence of Variabilities in EEG Dynamics During Motor Imagery-Based Multiclass Brain–Computer Interface
Abstract:
Inter-subject and inter-session variabilities pose a significant challenge in electroencephalogram (EEG)-based brain–computer interface (BCI) systems. Furthermore, high dimensional EEG montages introduce huge computational burden due to excessive number of channels involved. Two experimental, i.e., inter-session and inter-subject, variabilities of EEG dynamics during motor imagery (MI) tasks are investigated in this paper. In particular, the effect on the performance of the BCIs due to day-to-day variability in EEG dynamics during the alterations in cognitive stages is explored. In addition, the inter-subject BCIs feasibility between cortically synchronized and desynchronized subject pairs on pairwise performance associativity is further examined. Moreover, the consequences of integrating spatial brain dynamics of varying the number of channels - from specific regions of the brain - are also discussed in case of both the contexts. The proposed approach is validated on real BCI data set containing EEG data from four classes of MI tasks, i.e., left/right hand, both feet, and tongue, subjected prior to a preprocessing of three different spatial filtering techniques. Experimental results have shown that a maximum classification accuracy of around 58% was achieved for the inter-subject experimental case, whereas a 31% deviation was noticed in the classification accuracies across two sessions during the inter-session experimental case. In conclusion, BCIs, without the subject-and session-specific calibration and with lesser number of channels employed, play a vital role while promoting a generic and efficient framework for plug and play use.
Autors: Simanto Saha;Khawza Iftekhar Uddin Ahmed;Raqibul Mostafa;Leontios Hadjileontiadis;Ahsan Khandoker;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Feb 2018, volume: 26, issue:2, pages: 371 - 382
Publisher: IEEE
 
» Evolution of Global Product Development Networks: An Exploratory Study
Abstract:
Global Product Development (GPD) networks have evolved to satisfy the unique requirements essential to the successful adoption of corporate outsourcing and offshoring during development processes. Having reviewed the relevant literature associated with GPD, this paper seeks to contribute to the understanding of organizational considerations taken by GPD networks during their transitional processes. A retrospective case study analysis was conducted with 17 Italian companies classified into six GPD configurations (named the “Chess matrix”). Each classification was based on both developmental localization (local versus global) and product development process fragmentation; development activities are either entirely performed within the same development lab, eventually with the contribution of support/adaptive units, or they are split among development units. Using this classification system, an evolutionary model was adopted to illustrate the dynamic paths companies follow when transitioning toward new GPD configurations. With this framework and categorization process, it was deduced that three main variables drove each of the 17 companies: 1) market needs; 2) market extension; and 3) internal needs. These variables were determined based on the GPD approach each company adopted in pursuit of a stable profitable configuration that was achieved by either deliberately remaining in a certain configuration or by employing an evolutionary GPD development configuration. In recognizing that there is not a singularly optimal stable configuration, it is essential to recognize and identify the individual drivers being pursued by each enterprise when implementing specific configurations. Further research will be devoted to more extensively elaborate the paths within a larger sample of companies to identify unrevealed paths and drivers that move companies in their product development globalization efforts.
Autors: Margherita Pero;Monica Rossi;Sergio Terzi;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Feb 2018, volume: 65, issue:1, pages: 34 - 45
Publisher: IEEE
 
» Evolutionary Stability of Reputation-Based Incentive Mechanisms in P2P Systems
Abstract:
Free riding is a severe problem in P2P systems. Although many incentive mechanisms based on reputation have been proposed to mitigate problem of free riding, reputation management fails to evolve as an evolutionary stable strategy (ESS) due to cost involved in keeping track of reputation. We prove that a system setting with one time entry fee, imposed on new comers and distributed among the peers that calculate reputation, makes reputation-based resource allocation an ESS. Then, we simulate the system model using evolutionary dynamics for its performance evaluation.
Autors: Antriksh Goswami;Gopal Sharan Parashari;Ruchir Gupta;
Appeared in: IEEE Communications Letters
Publication date: Feb 2018, volume: 22, issue:2, pages: 268 - 271
Publisher: IEEE
 
» Exact Bit Error Rate Analysis for Color Shift Keying Modulation
Abstract:
In this letter, we present a new method to derive the exact analytical expression for the bit error rate (BER) of the color shift keying (CSK) modulation scheme over additive white Gaussian noise channel. We first exploit the coplanarity of CSK symbols, and build up a 2-D graphically symmetric space to simplify the BER analysis in the 3-D space of the signal transmitted via the red, green, and blue light beams. Thanks to the graphical symmetry of the symbols in the 2-D space, the symbol transition probabilities can be evaluated with less complexity. Then, with the aid of decision region partitioning, the exact symbol transition probabilities can be calculated. At last, the exact BER can be obtained by the weighted sum of all the symbol transition probabilities with the corresponding Hamming distances. Simulations are performed, and the results demonstrate that our presented BER analysis achieves more exact performance evaluation in both high and low signal-to-noise ratio regimes than the counterparts in other papers.
Autors: Jian Tang;Lin Zhang;Zhiqiang Wu;
Appeared in: IEEE Communications Letters
Publication date: Feb 2018, volume: 22, issue:2, pages: 284 - 287
Publisher: IEEE
 
» Exact Calculation of Noise Maps and ${g}$ -Factor in GRAPPA Using a ${k}$ -Space Analysis
Abstract:
Characterization of the noise distribution in magnetic resonance images has multiple applications, including quality assurance and protocol optimization. Noise characterization is particularly important in the presence of parallel imaging acceleration with multi-coil acquisitions, where the noise distribution can contain severe spatial heterogeneities. If the parallel imaging reconstruction is a linear process, an accurate noise analysis can be carried out by taking into account the correlations between all the samples involved. However, for -space-based techniques such as generalized autocalibrating partially parallel acquisition (GRAPPA), the exact analysis has been considered computationally prohibitive due to the very large size of the noise covariance matrices required to characterize the noise propagation from -space to image space. Previously proposed methods avoid this computational burden by formulating the GRAPPA reconstruction as a pixel-wise linear operation performed in the image space. However, these methods are not exact in the presence of non-uniform sampling of -space (e.g., containing a calibration region). For this reason, in this paper, we develop an accurate characterization of the noise distribution for self-calibrated parallel imaging in the presence of arbitrary Cartesian sampling patterns. By exploiting the symmetries and separability in the noise propagation process, the proposed method is computationally efficient and does not require large matrices. Under the assumption of a fixed reconstruction kernel, this method provides the precise distribution of the noise variance for each coil’s image. These coil-by-coil noise maps are subsequently combined according to the coil combination approach- used in image reconstruction, and therefore can be applied with both complex coil combination and root-sum-of-squares approaches. In this paper, we present the proposed noise characterization method and compare it to previous techniques using Monte Carlo simulations as well as phantom acquisitions.
Autors: Iñaki Rabanillo;Santiago Aja-Fernández;Carlos Alberola-López;Diego Hernando;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Feb 2018, volume: 37, issue:2, pages: 480 - 490
Publisher: IEEE
 
» Exact Solution for Elliptic Localization in Distributed MIMO Radar Systems
Abstract:
Elliptic localization is a range-based positioning technique exploiting multiple transmitter–receiver pairs, each of which provides separate bistatic range (BR) measurements. In this paper, a novel computationally efficient solution for locating a single target from BR measurements in distributed MIMO radar systems is proposed. Due to nonconvex nature of the associated maximum likelihood (ML) estimation problem, its globally optimal solution is difficult to obtain. We first reformulate the ML estimation as a nonconvex constrained weighted least squares problem. Owing to special structure of the resulting problem, it is recast as a convex problem, whose exact solution can be obtained in closed-form or near closed-form manner. Moreover, the proposed method is extended to localization in the presence of antenna location uncertainties. The positioning performance of the proposed method is shown to achieve the CRLB up to relatively high noise levels. Furthermore, numerical simulations demonstrate a significant performance improvement of the proposed method over the state-of-the-art algorithms.
Autors: Rouhollah Amiri;Fereidoon Behnia;Mohammad Amin Maleki Sadr;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2018, volume: 67, issue:2, pages: 1075 - 1086
Publisher: IEEE
 
» Examining the Impact of a Crude Oil Spill on the Permittivity Profile and Normalized Radar Cross Section of Young Sea Ice
Abstract:
An oil-in-sea ice mesocosm experiment was conducted at the University of Manitoba Sea-Ice Environmental Research Facility from January to March 2016 in which geophysical and electromagnetic parameters of the ice were measured, and general observations about the oil-contaminated ice were made. From the experimental measurements, the presence of crude oil appears to affect the temperature and bulk salinity profiles as well as the normalized radar cross section (NRCS) of the contaminated young sea ice. The measured temperature and bulk salinity profiles of the ice, as well as the crude oil distribution within the ice, were used to model the permittivity profile of the oil-contaminated ice by adapting two mixture models commonly used to describe sea ice to account for the presence of oil. Permittivity modeling results were used to simulate the NRCS of the oil-contaminated sea ice in an effort to determine the accuracy of the models. In addition, the application of X-ray microtomography in modeling the dielectric profile of oil-contaminated sea ice was examined. The sensitivity of the permittivity models for oil-contaminated sea ice to changes in temperature, frequency, and oil volume fraction was also examined.
Autors: Thomas D. Neusitzer;Nariman Firoozy;Tyler M. Tiede;Durell S. Desmond;Marcos J. L. Lemes;Gary A. Stern;Søren Rysgaard;Puyan Mojabi;David G. Barber;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Feb 2018, volume: 56, issue:2, pages: 921 - 936
Publisher: IEEE
 
» Exclusion of Linear Acceleration Signal in the MEMS Thermal Gyroscope
Abstract:
This letter identifies the source of linear acceleration signal in the microelectromechanical systems (MEMS) thermal gyroscope and provides a real-time solution to exclude it. The main culprit of the undesired acceleration signal is found to be lack of rotational symmetry due to Manhattan sensor topology. A higher level of symmetry is obtained by constructing a hybrid gyroscope using two individual devices operating in tandem but 180° out-of-phase. A precision rotary stage is used to test the duo. The experiments confirmed that higher symmetry is promising in excluding the acceleration signal. Compared with a single device, the hybrid gyroscope demonstrated 16-fold reduction in the acceleration signal and 5-fold improved acceleration to rotation sensitivities. [2017-0171]
Autors: Jamal Bahari;Carlo Menon;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Feb 2018, volume: 27, issue:1, pages: 19 - 21
Publisher: IEEE
 
» Expanding-Window BATS Code for Scalable Video Multicasting Over Erasure Networks
Abstract:
In this paper we consider scalable video multicasting over erasure networks with heterogeneous video quality requirements. With random linear network coding (RLNC) applied at the intermediate nodes the information received by the destinations is determined by the associated channel rank distributions based on which we obtain the optimal achievable code rate at the source node. We show that although a concatenation of priority encoded transmission (PET) with RLNC achieves the optimal code rate it incurs prohibitive high coding complexity. On the other hand batched sparse (BATS) code has been recently proposed for unicast networks which has low coding complexity with near-optimal overhead. However the existing BATS code design cannot be applied for multicast networks with heterogeneous channel rank distributions at different destinations. To this end we propose a novel expanding window BATS (EW-BATS) code where the input symbols are grouped into overlapped windows according to their importance levels. The more important symbols are encoded with lower rate and hence they can be decoded by more destinations while the less important symbols are encoded with higher rate and are only decoded by the destinations with high throughput for video quality enhancement. Based on asymptotical performance analysis we formulate the linear optimization problems to jointly optimize the degree distributions for each window and the window selection probabilities. Simulation results show that the proposed EW-BATS code satisfies the decoding requirements with much lower transmission overhead compared with separate BATS code where the degree distributions are separately optimized for each destination.
Autors: Xiaoli Xu;Yong Zeng;Yong Liang Guan;Lei Yuan;
Appeared in: IEEE Transactions on Multimedia
Publication date: Feb 2018, volume: 20, issue:2, pages: 271 - 281
Publisher: IEEE
 
» Experience With Online Partial-Discharge Measurement in High-Voltage Inverter-Fed Motors
Abstract:
Partial-discharge (PD) testing has long been an important tool for assessing the condition of the high-voltage insulation in motor and generator stator windings. In the past several years, many motors have been powered from inverters, which facilitate variable-speed motor operation. The most common drive used today is the voltage-source pulse-width modulation (VS-PWM) type. VS-PWM drives rated up to 13.8 kV are becoming more common in natural gas processing plants, as well as in other petrochemical facilities. Such drives generate high-voltage impulses in the kilovolt range with rise times in the submicrosecond range. These impulses are a form of severe electrical interference that can make difficult the online detection of PD (with magnitudes 1000 times smaller) due to the overlapping frequency content in PD and in the impulses. Thus, PD detection on medium-voltage VS-PWM systems has been a challenge in spite of the serious stator winding insulation aging that such drives may cause to these motors. This paper discusses the stator winding failure mechanisms that produce PD, including the insulation problems that VS-PWM drives can accelerate. A research project that lasted several years is reviewed. This project culminated in a prototype online PD monitoring system suitable for motors fed by VS-PWM drives.
Autors: Greg C. Stone;Howard G. Sedding;Connor Chan;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2018, volume: 54, issue:1, pages: 866 - 872
Publisher: IEEE
 
» Experiment for Radiation From Horizontal Loop Located on the Earth’s Surface
Abstract:
This paper develops a “ground-airborne” model for a horizontal large loop, proposes a novel noise cancellation technique, and conducts an experiment for verification. In the experiment, large horizontal loop located on the earth’s surface is employed as a source antenna to generate extremely low frequency magnetic fields. Using a potassium optically pumped magnetometer GSMP-35A suspended below the helicopter, the fields are recorded on three survey planes at different heights. Comparing the theoretical solution with experiments, the magnetic field envelopes are in good agreement with the theoretical solution and validity of the noise cancellation procedure is verified.
Autors: Xiaodong Qu;Feng Zhang;Guangyou Fang;
Appeared in: IEEE Sensors Journal
Publication date: Feb 2018, volume: 18, issue:4, pages: 1628 - 1635
Publisher: IEEE
 
» Experimental and Numerical Demonstration on the Gain and Power Saturation of Yb-Doped Double-Clad Fiber Amplifiers in Multiwavelength CW and Ultrafast Pulsed Operation
Abstract:
Experimental studies on gain and saturation of a Yb-doped double-cladding fiber amplifier accompanied with and interpreted by rigorous numerical simulations are presented. The saturation power, the value, and the spectral asymmetry of the output signal are experimentally characterized in both pulsed and continuous wave (CW) operation, and then, verified and interpreted numerically. Power conversion efficiency and quantum conversion efficiency of the amplifier are measured to be up to 55% and 58%, respectively. It is the first time, to the best of our knowledge, to demonstrate a numerical model for the pulsed operation based on the interaction of vector coupled nonlinear Schrodinger equations and the rate equations of the Yb-doped double-clad fiber taking into account all high-order dispersion parameters and the variation of gain coefficient during pulse propagation. A good agreement between numerical and experimental results is observed providing interpretations to the results. The numerical models and the experimental demonstrations provide guidance for the design and analysis of Yb-doped double-cladding fiber amplifiers both in pulsed and CW operation.
Autors: Mohamed A. Abdelalim;Hussein E. Kotb;Ebin Joseph;Ahmed M. Othman;Hanan Anis;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 12
Publisher: IEEE
 
» Experimental Characterization of the Inline-Screw-Feeding Vacuum-Arc-Thruster Operation
Abstract:
A CubeSat-class micropropulsion system is being developed at the Aerospace Plasma Laboratory, Technion-Israel Institute of Technology, called the inline-screw-feeding vacuum-arc thruster (ISF-VAT). The ISF-VAT couples a conventional VAT triggerless ignition geometry with an active feeding system that mechanically drives the cathode propellant in a periodic helical motion. The thruster performance is found to be highly regular for at least 700 000 pulses, h of continuous operation, with good pulse to pulse repeatability. The measured average thrust-to-power ratio is /W. Observations of the cathode and insulator erosion patterns show that while the cathode electrode geometry is maintained by the feeding system, the ceramic insulator is also being consumed. The maximum insulator erosion rate was determined to be /7 of the cathode consumption rate. The thruster lifetime is, therefore, determined by the length of the insulator.
Autors: Igal Kronhaus;Matteo Laterza;Alexander R. Linossier;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Feb 2018, volume: 46, issue:2, pages: 283 - 288
Publisher: IEEE
 
» Experimental Study on Directionality of Ultrasonic Wave Coupling Using Surface-Bonded Fiber Bragg Grating Sensors
Abstract:
Recent studies demonstrated the potential of increasing the Lamb wave detection sensitivity of fiber Bragg grating (FBG) sensors by bonding the optical fiber away from the grating location, instead of the conventional method of bonding the FBG directly. The FBG located at a remote location further along the optical fiber collects the guided traveling wave in the optical fiber generated from the Lamb wave signal. This remote bonding method could potentially be extended to a series of multiplexed FBGs. However, previous experiments also detected coupling to guided traveling waves in both directions in the optical fiber, which could have significant effects on multiplexed signals. In this paper, we measure the coupled signal amplitudes in both forward and backward directions, when ultrasonic waves couple from a thin plate to an optical fiber and from an optical fiber to a thin plate. The forward- and backward-induced modes are measured in both the optical fiber and the plate. The same experiment is then performed for the case when ultrasonic signal is coupled from the optical fiber to the plate. In addition, two different types of bonding, cyanoacrylate adhesive and frictional bond, are explored to investigate how the signal conversion depends on the bonding method. The results demonstrate that the coupling of ultrasonic waves from a thin structure to an optical fiber and from an optical fiber to the structure is complex. The coupling does not only occur in the direction of the wave propagation, but can be coupled into both forward and backward modes, depending on the bonding configuration used.
Autors: Junghyun Wee;Drew Hackney;Philip Bradford;Kara Peters;
Appeared in: Journal of Lightwave Technology
Publication date: Feb 2018, volume: 36, issue:4, pages: 932 - 938
Publisher: IEEE
 
» Experimental Time Evolution Study of the HfO2-Based IMPLY Gate Operation
Abstract:
In the last years, memristor devices have been proposed as key elements to develop a new paradigm to implement logic gates. In particular, the memristor-based material implication (IMPLY) gate has been presented as a potential powerful basis for logic applications. In the literature, the IMPLY operation has been widely simulated, but most of the efforts have been just focused on accomplishing its truth table, only considering the initial and final states of the gate. However, a complete understanding of the time evolution between states is still missing and barely reported yet. In this paper, the time evolution of the memristors involved in an IMPLY gate are studied in detail for every case of the gate. Furthermore, the impact on IMPLY gate operation of the internal resistor connected in series with the memristors of the IMPLY gate is included.
Autors: Marcos Maestro-Izquierdo;Javier Martin-Martinez;Albert Crespo Yepes;Manel Escudero;Rosana Rodríguez;Montserrat Nafría;Xavier Aymerich;Antonio Rubio;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 404 - 410
Publisher: IEEE
 
» Experimental Validation of a Novel Architecture Based on a Dual-Stage Converter for Off-Board Fast Battery Chargers of Electric Vehicles
Abstract:
The experimental validation of a novel architecture of an off-board, three-phase fast battery charger for electric vehicles (EVs) with innovative operation modes is presented in this paper. The proposed EV fast battery charger is based on a dual-stage power converter (ac-dc and dc-dc) sharing the same dc link. The ac-dc stage is used as an interface between the power grid and the dc link. It is composed of the parallel association of two full-bridge voltage-source converters, and allows control of the grid current and of the dc-link voltage. The dc-dc stage is used as an interface between the dc link and the batteries. It is constituted by a bidirectional three-level asymmetrical voltage-source converter, and controls the flux of current during the EV battery charging process. Compared with the traditional solutions used for EV fast battery chargers, the proposed architecture operates as an interleaved converter, facilitating the reduction of the passive filters size, and the grid current harmonic distortion for the same switching frequency. Throughout the paper, the ac-dc and dc-dc stages, and the digital control algorithms are described in detail. The experimental validation was performed in a laboratory using a developed EV fast battery charger prototype, operating through the grid-to-vehicle and the proposed charger-to-grid modes, exchanging active, and reactive power with the power grid.
Autors: Vítor Monteiro;João C. Ferreira;Andrés A. Nogueiras Meléndez;Carlos Couto;João Luiz Afonso;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Feb 2018, volume: 67, issue:2, pages: 1000 - 1011
Publisher: IEEE
 
» Experimental Validation of Dual H-Bridge Current Flow Controllers for Meshed HVdc Grids
Abstract:
The current-carrying capability of dc lines is limited by their thermal and electric stress limits. Thus, the line current must be maintained within the permissible operational region to protect the lines from damage. In a dense dc grid, control over each line current cannot be achieved without including additional control devices. In this paper, a dual H-bridge current flow controller (2B-CFC) is used to manage the dc grid line power flow by providing dc voltage compensation in series with dc lines. A centralized hierarchical control system is proposed to coordinate the operation between multiple CFCs. A novel voltage-sharing control scheme is demonstrated. It is shown that such a scheme reduces the workload on a single CFC by sharing the required control voltage between multiple CFCs, and, in addition, can be used to avoid control conflicts among active CFCs during communication failure. An experimental platform consisting of a three-terminal dc grid and small-scale 2B-CFC prototypes has been developed to validate the concepts. For completeness, the CFC performance has been analyzed for overload conditions and when no communication exists. Small-scale dc circuit breakers have been developed to study the CFC performance under a pole-to-pole fault.
Autors: Senthooran Balasubramaniam;Carlos E. Ugalde-Loo;Jun Liang;Tibin Joseph;Rose King;Andrzej Adamczyk;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2018, volume: 33, issue:1, pages: 381 - 392
Publisher: IEEE
 
» Experimentally Validated Dispersion Tailoring in a Silicon Strip Waveguide With Alumina Thin-Film Coating
Abstract:
We propose a silicon strip waveguide structure with alumina thin-film coating in-between the core and the cladding for group-velocity dispersion tailoring. By carefully designing the core dimension and the coating thickness, a spectrally-flattened near-zero anomalous group-velocity dispersion within the telecom spectral range is obtained, which is predicted to significantly broaden the bandwidth of four-wave mixing. We validate this by characterizing the wavelength conversion in a waveguide sample by atomic layer deposition technology, which to our best knowledge is the first experimental demonstration of the proposed structure. Due to the alumina thin-film coating, the wavelength conversion bandwidth reaches , an increase by a factor of 1.3 compared to the corresponding structure without coating. This method can also be applied to other material platforms and applications requiring accurate group-velocity dispersion control.
Autors: Kai Guo;Jesper. B. Christensen;Xiaodong Shi;Erik. N. Christensen;Li Lin;Yunhong Ding;Haiyan Ou;Karsten Rottwitt;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 8
Publisher: IEEE
 
» Explicit Edge Inconsistency Evaluation Model for Color-Guided Depth Map Enhancement
Abstract:
Color-guided depth enhancement is used to refine depth maps according to the assumption that the depth edges and the color edges at the corresponding locations are consistent. In methods on such low-level vision tasks, the Markov random field (MRF), including its variants, is one of the major approaches that have dominated this area for several years. However, the assumption above is not always true. To tackle the problem, the state-of-the-art solutions are to adjust the weighting coefficient inside the smoothness term of the MRF model. These methods lack an explicit evaluation model to quantitatively measure the inconsistency between the depth edge map and the color edge map, so they cannot adaptively control the efforts of the guidance from the color image for depth enhancement, leading to various defects such as texture-copy artifacts and blurring depth edges. In this paper, we propose a quantitative measurement on such inconsistency and explicitly embed it into the smoothness term. The proposed method demonstrates promising experimental results compared with the benchmark and state-of-the-art methods on the Middlebury ToF-Mark, and NYU data sets.
Autors: Yifan Zuo;Qiang Wu;Jian Zhang;Ping An;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Feb 2018, volume: 28, issue:2, pages: 439 - 453
Publisher: IEEE
 
» Exploiting Elastic Energy Storage for “Blind” Cyclic Manipulation: Modeling, Stability Analysis, Control, and Experiments for Dribbling
Abstract:
For creating robots that are capable of human-like performance in terms of speed, energetic properties, and robustness, intrinsic compliance is a promising design element. In this paper, we investigate the principle effects of elastic energy storage and release for basketball dribbling in terms of open-loop cycle stability. We base the analysis, which is performed for the 1-degree-of-freedom (DoF) case, on error propagation, peak power performance during hand contact, and robustness with respect to varying hand stiffness. As the ball can only be controlled during contact, an intrinsically elastic hand extends the contact time and improves the energetic characteristics of the process. To back up our basic insights, we extend the 1-DoF controller to 6-DoFs and show how passive compliance can be exploited for a 6-DoF cyclic ball dribbling task with a 7-DoF articulated Cartesian impedance controlled robot. As a human is able to dribble blindly, we decided to focus on the case of contact force sensing only, i.e., no visual information is necessary in our approach. We show via simulation and experiment that it is possible to achieve a stable dynamic cycle based on the 1-DoF analysis for the primary vertical axis together with control strategies for the secondary translations and rotations of the task. The scheme allows also the continuous tracking of a desired dribbling height and horizontal position. The approach is also used to hypothesize about human dribbling and is validated with captured data.
Autors: Sami Haddadin;Kai Krieger;Alin Albu-Schäffer;Torsten Lilge;
Appeared in: IEEE Transactions on Robotics
Publication date: Feb 2018, volume: 34, issue:1, pages: 91 - 112
Publisher: IEEE
 
» Exploiting Feature and Class Relationships in Video Categorization with Regularized Deep Neural Networks
Abstract:
In this paper, we study the challenging problem of categorizing videos according to high-level semantics such as the existence of a particular human action or a complex event. Although extensive efforts have been devoted in recent years, most existing works combined multiple video features using simple fusion strategies and neglected the utilization of inter-class semantic relationships. This paper proposes a novel unified framework that jointly exploits the feature relationships and the class relationships for improved categorization performance. Specifically, these two types of relationships are estimated and utilized by imposing regularizations in the learning process of a deep neural network (DNN). Through arming the DNN with better capability of harnessing both the feature and the class relationships, the proposed regularized DNN (rDNN) is more suitable for modeling video semantics. We show that rDNN produces better performance over several state-of-the-art approaches. Competitive results are reported on the well-known Hollywood2 and Columbia Consumer Video benchmarks. In addition, to stimulate future research on large scale video categorization, we collect and release a new benchmark dataset, called FCVID, which contains 91,223 Internet videos and 239 manually annotated categories.
Autors: Yu-Gang Jiang;Zuxuan Wu;Jun Wang;Xiangyang Xue;Shih-Fu Chang;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Feb 2018, volume: 40, issue:2, pages: 352 - 364
Publisher: IEEE
 
» Exploiting Full/Half-Duplex User Relaying in NOMA Systems
Abstract:
In this paper, a novel cooperative non-orthogonal multiple access (NOMA) system is proposed, where one near user is employed as decode-and-forward relaying switching between full-duplex (FD) and half-duplex (HD) mode to help a far user. Two representative cooperative relaying scenarios are investigated insightfully. The first scenario is that no direct link exists between the base station (BS) and far user. The second scenario is that the direct link exists between the BS and far user. To characterize the performance of potential gains brought by the FD NOMA in two considered scenarios, three performance metrics outage probability, ergodic rate, and energy efficiency are discussed. More particularly, we derive new closed-form expressions for both exact and asymptotic outage probabilities as well as delay-limited throughput for two NOMA users. Based on the derived results, the diversity orders achieved by users are obtained. We confirm that the use of direct link overcomes zero diversity order of far NOMA user inherent to FD relaying. In addition, we derive new closed-form expressions for asymptotic ergodic rates. Based on these, the high signal-to-noise ratio (SNR) slopes of two users for FD NOMA are obtained. Simulation results demonstrate that: 1) the FD NOMA is superior to the HD NOMA in terms of outage probability and ergodic sum rate in the low SNR region; and 2) in delay-limited transmission mode, the FD NOMA has higher energy efficiency than the HD NOMA in the low SNR region; However, in delay-tolerant transmission mode, the system energy efficiency of the HD NOMA exceeds the FD NOMA in the high SNR region.
Autors: Xinwei Yue;Yuanwei Liu;Shaoli Kang;Arumugam Nallanathan;Zhiguo Ding;
Appeared in: IEEE Transactions on Communications
Publication date: Feb 2018, volume: 66, issue:2, pages: 560 - 575
Publisher: IEEE
 
» Exploring 3-D Printing for New Applications: Novel Inkjet- and 3-D-Printed Millimeter-Wave Components, Interconnects, and Systems
Abstract:
This article outlines a number of inkjet-/three-dimensional (3-D)-printed prototypes of RF and millimeter-wave (mmW) components, interconnects, and systems. We pay special attention to the major challenges related to applying current multidimensional printing technologies to the fabrication of flexible multichip modules (MCMs) and high-performance mmW components.
Autors: Ryan Bahr;Bijan Tehrani;Manos M. Tentzeris;
Appeared in: IEEE Microwave Magazine
Publication date: Feb 2018, volume: 19, issue:1, pages: 57 - 66
Publisher: IEEE
 
» Exploring Hybrid STT-MTJ/CMOS Energy Solution in Near-/Sub-Threshold Regime for IoT Applications
Abstract:
Emerging memories have been developed to achieve energy efficiency target in the Internet of Things era. Spin transfer torque magnetic tunnel junction (STT-MTJ)-based nonvolatile (NV) memory has demonstrated attractive performance because of zero standby power, reduced switching power, infinite endurance, and high density. Meanwhile, hybrid STT-MTJ/CMOS integration is a promising solution to overcome the bottleneck of dynamic and leakage power dissipation. In this paper, ultralow power methodologies are developed at device and circuit level in 28 nm fully depleted silicon on insulator CMOS technology. Supply voltage scaling, near-/sub-threshold () operation, and back-bias adjustment are demonstrated, showing 81% dynamic power reduction under 0.6 V near- sensing operation, with the tradeoff of 6.2% increased sensing error rate. Through the case study on STT-MTJ-based NV flip-flops (NV-FFs), up to 76% dynamic and 79% leakage power saving can be realized in ultra-low power NV-FF implementation.
Autors: Hao Cai;You Wang;Lirida Alves de Barros Naviner;Jun Yang;Weisheng Zhao;
Appeared in: IEEE Transactions on Magnetics
Publication date: Feb 2018, volume: 54, issue:2, pages: 1 - 9
Publisher: IEEE
 
» Exploring the Tuning Range of Channel Filters for Satellite Applications Using Electromagnetic-Based Computer Aided Design Tools
Abstract:
The objective of this paper is to use electromagnetic-based computer-aided design (CAD) tools to investigate the maximum tuning range of channel filters, typically used in satellite payloads. Both circular and rectangular waveguide technologies are investigated. The results of the investigation show that single-mode rectangular waveguide implementations offer substantially wider tuning range, as opposed to classical dual-mode circular waveguide implementations. In addition to simulations, measurements are also presented indicating very good agreement with theory, thereby fully validating the CAD procedure.
Autors: Javier Ossorio;Joaquin Vague;Vicente E. Boria;Marco Guglielmi;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2018, volume: 66, issue:2, pages: 717 - 725
Publisher: IEEE
 
» Exploring the Use of Native Spider Silk as an Optical Fiber for Chemical Sensing
Abstract:
A spider uses up to seven different types of silk, all having specific functions, as building material, weapon, and sensory organ to detect the presence of preys on its web. Recently, scientists have put under the limelight the extraordinary properties of this ancient material. Indeed, native silk, directly extracted from spiders, is a tough, biodegradable, and biocompatible thread used mainly for tissue engineering and textile applications. Blessed with outstanding optical properties, this protein strand can also be used as a bioresorbable optical fiber and is, moreover, intrinsically sensitive to chemical compounds. In this communication, the waveguiding properties of native dragline silk are assessed and a pioneering proof-of-concept experiment using pristine spider silk as an optical fiber to measure humidity content is demonstrated. The feasibility of using silk-based optical fiber chemical sensors is also discussed.
Autors: Kenny Hey Tow;Desmond M. Chow;Fritz Vollrath;Isabelle Dicaire;Tom Gheysens;Luc Thévenaz;
Appeared in: Journal of Lightwave Technology
Publication date: Feb 2018, volume: 36, issue:4, pages: 1138 - 1144
Publisher: IEEE
 
» Exploring Triangle-Free Dense Structures
Abstract:
Triadic closure is ubiquitous in social networks, which refers to the property among three individuals, A, B, and C, such that if there exist strong ties between A-B and A-C, then there must be a strong or weak tie between B-C. Related to triadic closure, the number of triangles has been extensively studied since it can be effectively used as a metric to analyze the structure and function of a network. In this paper, from a different viewpoint, we study triangle-free dense structures which have received little attention. We focus on where there are two subsets of three vertices, a vertex in a subset has an edge connected to every vertex in another subset while it does not have an edge to any other vertex in the same subset. Such in general implies a philosophy contradiction: (a) Any two individuals are friends if they have no common friends, and (b) Any two individuals are not friends if they have common friends. However, we find such induced does exist frequently, and they do not disappear over time over a real academic collaboration network. In addition, in the real datasets tested, nearly all edges appearing in appear in some triangles. We analyze the expected numbers of induced ) in four representative random graph models, namely, Erdős-Rényi random graph model, Watts-Strogatz small-world model, Barabási-Albert preferential attachment model, and configuration model, and give an algorithm to enumerate all distinct in an undirected social network. We conduct extensive experiments on both real and synthetic datasets to confirm our findings. As an application, such found helps to find new stars collaborated by well-known figures who themselves do not collaborate.
Autors: Can Lu;Jeffrey Xu Yu;Hao Wei;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Feb 2018, volume: 30, issue:2, pages: 278 - 291
Publisher: IEEE
 
» Explosion Protection of a Motor Integrated With a Compressor Using a Purging and Pressurization Technique With a Flammable Gas Above the UFL
Abstract:
This paper describes construction and test methods developed for a high-speed induction motor integrated with a compressor using the explosion protection technique of purged and pressurized by flammable gas, which is maintained above the upper flammable limit (UFL) after purging the system of air. The National Electrical Code [NEC or national fire protection agency (NFPA) 70 [1]] permits motors to be submerged in a flammable gas or vapor that is at a pressure greater than atmospheric pressure, and that is flammable only when mixed with air as the explosion protection means. Purging and pressurizing of electrical equipment with air or inert gas to the requirements of NFPA 496 [2] is widely known, but those requirements do not apply to a motor designed to be immersed in a flammable fluid. Specific requirements were developed for a high-speed induction motor–compressor supplied by a variable frequency power supply. This motor is directly connected to a natural gas or hydrocarbon mixture compressor, and the system is purged and pressurized with flammable gas that is maintained above the UFL and pressurized above atmospheric pressure. Though the NEC [1] has permitted this protection concept for many years, a set of construction and testing requirements needed to be developed and published for certification purposes. These types of motors have been operating safely in Europe and in North America for many years with a similar concept for the protection technique. This paper will discuss using the flammable gas above the UFL protection technique, and the development of the construction and testing requirements for it.
Autors: Bharat Mistry;Donald W. Ankele;Roberto Baldocci;Emilie Ourion;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Feb 2018, volume: 54, issue:1, pages: 883 - 888
Publisher: IEEE
 
» Exponential Pointwise Stabilization of Semilinear Parabolic Distributed Parameter Systems via the Takagi–Sugeno Fuzzy PDE Model
Abstract:
This paper deals with the problem of exponential stabilization for nonlinear parabolic distributed parameter systems using the Takagi–Sugeno (T–S) fuzzy partial differential equation (PDE) model, where a finite number of actuators are active only at some specified points of the spatial domain (these actuators are referred to as pointwise actuators). Three cases of state feedback are respectively considered in this study as follows: full state feedback, piecewise state feedback, and collocated pointwise state feedback. It is initially assumed that a T–S fuzzy PDE model obtained via the sector nonlinearity approach is employed to accurately represent the semilinear parabolic PDE system. Based on the obtained T–S fuzzy PDE model, Lyapunov-based design methodologies of fuzzy feedback control laws are subsequently derived for the above three state feedback cases by using the vector-valued Wirtinger's inequality to guarantee locally exponential pointwise stabilization of the semilinear PDE system, and presented in terms of standard linear matrix inequalities (LMIs). Moreover, the favorable property offered by sharing all the same premises in the T–S fuzzy PDE models and fuzzy controllers is not applicable for the case of collocated pointwise state feedback. A parameterized LMI is introduced for this case to enhance the stabilization ability of the fuzzy controller. Finally, the merit and effectiveness of the proposed design methods are demonstrated by numerical simulation results of two examples.
Autors: Jun-Wei Wang;Huai-Ning Wu;
Appeared in: IEEE Transactions on Fuzzy Systems
Publication date: Feb 2018, volume: 26, issue:1, pages: 155 - 173
Publisher: IEEE
 
» Expression-Invariant Age Estimation Using Structured Learning
Abstract:
In this paper, we investigate and exploit the influence of facial expressions on automatic age estimation. Different from existing approaches, our method jointly learns the age and expression by introducing a new graphical model with a latent layer between the age/expression labels and the features. This layer aims to learn the relationship between the age and expression and captures the face changes which induce the aging and expression appearance, and thus obtaining expression-invariant age estimation. Conducted on three age-expression datasets (FACES [1] , Lifespan [2] and NEMO [3] ), our experiments illustrate the improvement in performance when the age is jointly learnt with expression in comparison to expression-independent age estimation. The age estimation error is reduced by 14.43, 37.75 and 9.30 percent for the FACES, Lifespan and NEMO datasets respectively. The results obtained by our graphical model, without prior-knowledge of the expressions of the tested faces, are better than the best reported ones for all datasets. The flexibility of the proposed model to include more cues is explored by incorporating gender together with age and expression. The results show performance improvements for all cues.
Autors: Zhongyu Lou;Fares Alnajar;Jose M. Alvarez;Ninghang Hu;Theo Gevers;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Feb 2018, volume: 40, issue:2, pages: 365 - 375
Publisher: IEEE
 
» Extended Random Walker for Shadow Detection in Very High Resolution Remote Sensing Images
Abstract:
The existence of shadows in very high resolution satellite images obstructs image interpretation and the following applications, such as target detection and recognition. Traditional shadow detection methods consider only the pixel-level properties, such as color and intensity of image pixels, and thus, may produce errors around object boundaries. To overcome this problem, a novel shadow detection algorithm based on extended random walker (ERW) is proposed by jointly integrating both shadow property and spatial correlations among adjacent pixels. First, a set of training samples is automatically generated via an improved Otsu-based thresholding method. Then, the support vector machine is applied to obtain an initial detection map, which categorizes all the pixels in the scene into shadow and nonshadow. Finally, the initial detection map is refined with the ERW model, which can simultaneously characterize the shadow property and spatial information in satellite images to further improve shadow detection accuracy. Experiments performed on five real remote sensing images demonstrate the superiority of the proposed method over several state-of-the-art methods in terms of detection accuracy.
Autors: Xudong Kang;Yufan Huang;Shutao Li;Hui Lin;Jon Atli Benediktsson;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Feb 2018, volume: 56, issue:2, pages: 867 - 876
Publisher: IEEE
 
» Extending 3-bit Burst Error-Correction Codes With Quadruple Adjacent Error Correction
Abstract:
The use of error-correction codes (ECCs) with advanced correction capability is a common system-level strategy to harden the memory against multiple bit upsets (MBUs). Therefore, the construction of ECCs with advanced error correction and low redundancy has become an important problem, especially for adjacent ECCs. Existing codes for mitigating MBUs mainly focus on the correction of up to 3-bit burst errors. As the technology scales and cell interval distance decrease, the number of affected bits can easily extend to more than 3 bit. The previous methods are therefore not enough to satisfy the reliability requirement of the applications in harsh environments. In this paper, a technique to extend 3-bit burst error-correction (BEC) codes with quadruple adjacent error correction (QAEC) is presented. First, the design rules are specified and then a searching algorithm is developed to find the codes that comply with those rules. The matrices of the 3-bit BEC with QAEC obtained are presented. They do not require additional parity check bits compared with a 3-bit BEC code. By applying the new algorithm to previous 3-bit BEC codes, the performance of 3-bit BEC is also remarkably improved. The encoding and decoding procedure of the proposed codes is illustrated with an example. Then, the encoders and decoders are implemented using a 65-nm library and the results show that our codes have moderate total area and delay overhead to achieve the correction ability extension.
Autors: Jiaqiang Li;Pedro Reviriego;Liyi Xiao;Costas Argyrides;Jie Li;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Feb 2018, volume: 26, issue:2, pages: 221 - 229
Publisher: IEEE
 
» Extension of NVNA Baseband Measurement for PA Characterization Under Complex Modulation
Abstract:
We investigated the measurement techniques of the nonlinear vector network analyzer (NVNA) test bench, to fully characterize the nonlinear behavior of radio frequency (RF) power amplifiers (PAs) driven by complex modulated signals. In order to extend the baseband measurements, two kinds of NVNA phase reference approaches are developed as alternative solutions, so that the baseband phase measurements can be achieved with those of modulated components at multiharmonic RF bands. In the first approach, a modulated baseband signal is combined with another modulated RF one to become the desired NVNA phase reference. While as an alternative solution, the second phase reference design is based on a “stepped” multisine, which is stepped through the baseband and each harmonic following the NVNA swept measurements, to achieve stable phase measurements. To validate these proposed NVNA test bench designs, an RF PA, driven by a large-signal long-term evolution-like multisine, was tested and compared with digital real-time oscilloscope measurements.
Autors: Yichi Zhang;Xiaotao Guo;Zhao He;David A. Humphreys;Lifeng Wang;Wei Zhao;Zilong Zhang;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2018, volume: 66, issue:2, pages: 1131 - 1141
Publisher: IEEE
 
» Extracting and Defining Flexibility of Residential Electrical Vehicle Charging Loads
Abstract:
The popularization of electric vehicles raises concerns about their negative impact on the electrical grid. Extracting electric vehicle charging load patterns is a key factor that allows smart grid operators to make intelligent and informed decisions about conserving energy and promoting the stability of the electrical grid. This paper presents an unsupervised algorithm to extract electric vehicle charging load patterns nonintrusively from the smart meter data. Furthermore, a method to define flexibility for the collective electric vehicle charging demand by analyzing the time-variable patterns of the aggregated electric vehicle charging behaviors is presented. Validation results on real residential loads have shown that the proposed approach is a promising solution to extract electric vehicle charging loads and that the approach can effectively mitigate the interference of other appliances that have similar load behaviors as electric vehicles. Furthermore, a case study on real residential data to analyze electric vehicle charging trends and quantify the flexibility achievable from the aggregated electric vehicle load in different time periods is presented.
Autors: Amr A. Munshi;Yasser Abdel-Rady I. Mohamed;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2018, volume: 14, issue:2, pages: 448 - 461
Publisher: IEEE
 
» F-DES: Fast and Deep Event Summarization
Abstract:
In the multimedia era a large volume of video data can be recorded during a certain period of time by multiple cameras. Such a rapid growth of video data requires both effective and efficient multiview video summarization techniques. The users can quickly browse and comprehend a large amount of audiovisual data. It is very difficult in real-time to manage and access the huge amount of video-content-handling issues of interview dependencies significant variations in illumination and presence of many unimportant frames with low activity. In this paper we propose a local-alignment-based FASTA approach to summarize the events in multiview videos as a solution of the aforementioned problems. A deep learning framework is used to extract the features to resolve the problem of variations in illumination and to remove fine texture details and detect the objects in a frame. Interview dependencies among multiple views of video are then captured via the FASTA algorithm through local alignment. Finally object tracking is applied to extract the frames with low activity. Subjective as well as objective evaluations clearly indicate the effectiveness of the proposed approach. Experiments show that the proposed summarization method successfully reduces the video content while keeping momentous information in the form of events. A computing analysis of the system also shows that it meets the requirement of real-time applications.
Autors: Krishan Kumar;Deepti D. Shrimankar;
Appeared in: IEEE Transactions on Multimedia
Publication date: Feb 2018, volume: 20, issue:2, pages: 323 - 334
Publisher: IEEE
 
» Face-Centered Anisotropic Surface Impedance Boundary Conditions in FDTD
Abstract:
Thin-sheet models are essential to allow shielding effectiveness of composite enclosures and vehicles to be modeled. Thin dispersive sheets are often modeled using surface-impedance models in finite-difference time-domain (FDTD) codes in order to deal efficiently with the multiscale nature of the overall structure. Such boundary conditions must be applied to collocated tangential electric and magnetic fields on either side of the surface; this is usually done on the edges of the FDTD mesh cells at the electric field sampling points. However, these edge-based schemes are difficult to implement accurately on stair-cased surfaces. Here, we present a novel face-centered approach to the collocation of the fields for the application of the boundary condition. This approach naturally deals with the ambiguities in the surface normal that arise at the edges on stair-cased surfaces, allowing a simpler implementation. The accuracy of the new scheme is compared to edge-based and conformal approaches using both planar sheet and spherical shell canonical test cases. Staircasing effects are quantified and the new face-centered scheme is shown have up to 3-dB lower error than the edge-based approach in the cases considered, without the complexity and computational cost of conformal techniques.
Autors: Ian D. Flintoft;Samuel A. Bourke;John F. Dawson;Jesus Alvarez;Miguel Ruiz Cabello;Martin P. Robinson;Salvador G. Garcia;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Feb 2018, volume: 66, issue:2, pages: 643 - 650
Publisher: IEEE
 
» Facile Room Temperature Routes to Improve Performance of IGZO Thin-Film Transistors by an Ultrathin Al2O3 Passivation Layer
Abstract:
Although oxide thin-film transistors (TFTs) have drawn great interests in flexible displays, a key obstacle is the requirement of high-temperature annealing to realized mobility>10 cm. In this paper, a fully room-temperature strategy, involving the deposition of ~10 nm In–Ga–Zn–O (IGZO) channel layer and ~4 nm Al2O3 passivation layer, is introduced. The as-prepared flexible TFT on polymide substrate exhibits a saturation mobility of 15.3 cm, of 3.08 V, and on/off current ratio of . Thickness-dependent analysis indicates that the interface between Al2O3 and IGZO is composed of negative O-rich layer, which impel the energy band bending inside the IGZO layers and release of electrons from traps. This paper opens up a route to achieve fully room-temperature fabrication of high-performance flexible TFT.
Autors: Honglong Ning;Yong Zeng;Zeke Zheng;Hongke Zhang;Zhiqiang Fang;Rihui Yao;Shiben Hu;Xiaoqing Li;Junbiao Peng;Weiguang Xie;Xubing Lu;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Feb 2018, volume: 65, issue:2, pages: 537 - 541
Publisher: IEEE
 
» Factor Graph-Based Equalization for Two-Way Relaying With General Multi-Carrier Transmissions
Abstract:
Multi-carrier transmission schemes with general non-orthogonal waveforms provide a flexible time-frequency resource allocation and are bandwidth efficient. However, the interference inherently introduced by the non-orthogonal waveforms always requires a higher order equalizer at the receiver. Depending on the localization properties of the applied waveform, the structure and the complexity of this equalizer is adapted to consider channel influences, like carrier frequency and timing offsets. Especially for two-phase two-way relaying channels (TWRCs), where two users simultaneously transmit data on the same resources, a robust transmission scheme in presence of practical constraints such as asynchronicity is of utmost importance. This paper focuses on the utilization of general multi-carrier transmission schemes applied to TWRCs and the utilization of factor graph-based equalizers (FGEs) at the relay in order to mitigate the impacts of the physical channels, offsets, and the non-orthogonal waveforms. In combination with the subsequent physical-layer network coding detection/decoding scheme, this combination allows for a flexible design of the waveforms and the FGE to meet the complexity-performance trade-off at the relay. As demonstrated by numerical evaluation results, the proposed multi-carrier scheme with well-localized waveforms utilizing FGEs outperforms orthogonal frequency division multiplexing in TWRC for a wide range of practical impacts.
Autors: Matthias Woltering;Dirk Wübben;Armin Dekorsy;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Feb 2018, volume: 17, issue:2, pages: 1212 - 1225
Publisher: IEEE
 
» Fair Resource Allocation for Data-Intensive Computing in the Cloud
Abstract:
To address the computing challenge of ‘big data’, a number of data-intensive computing frameworks (e.g., MapReduce, Dryad, Storm and Spark) have emerged and become popular. YARN is a de facto resource management platform that enables these frameworks running together in a shared system. However, we observe that, in cloud computing environment, the fair resource allocation policy implemented in YARN is not suitable because of its memoryless resource allocation fashion leading to violations of a number of good properties in shared computing systems. This paper attempts to address these problems for YARN. Both single-level and hierarchical resource allocations are considered. For single-level resource allocation, we propose a novel fair resource allocation mechanism called Long-Term Resource Fairness (LTRF) for such computing. For hierarchical resource allocation, we propose Hierarchical Long-Term Resource Fairness (H-LTRF) by extending LTRF. We show that both LTRF and H-LTRF can address these fairness problems of current resource allocation policy and are thus suitable for cloud computing. Finally, we have developed LTYARN by implementing LTRF and H-LTRF in YARN, and our experiments show that it leads to a better resource fairness than existing fair schedulers of YARN.
Autors: Shanjiang Tang;Bu-Sung Lee;Bingsheng He;
Appeared in: IEEE Transactions on Services Computing
Publication date: Feb 2018, volume: 11, issue:1, pages: 20 - 33
Publisher: IEEE
 
» Fall Detection Using Deep Learning in Range-Doppler Radars
Abstract:
In this paper, we propose an approach that uses deep learning to detect a human fall. The proposed approach automatically captures the intricate properties of the radar returns. In order to minimize false alarms, we fuse information from both the time-frequency and range domains. Experimental data is used to demonstrate the superiority of the deep learning based approach in comparison with the principal component analysis method and those methods incorporating predefined physically interpreted features.
Autors: Branka Jokanović;Moeness Amin;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Feb 2018, volume: 54, issue:1, pages: 180 - 189
Publisher: IEEE
 
» Far-Field Sub-Wavelength Imaging of Two-Dimensional Extended Target Aided By Compact Planar Resonant Structures
Abstract:
Two kinds of compact planar electrical resonant structures (PERSs) are proposed as the solution to realize far-field sub-wavelength imaging of extended target. The proposed structures have their advantages in low profile, compact size, and electrical coupling property. The conversion between evanescent and propagation waves of the two structures enables the sub-wavelength information to be carried to far-field. The first PERS consists of periodically distributed spiral resonators. With the help of background Green's function, sub-wavelength images of two-dimensional extended target with the resolutions of λ/11 from simulation and λ/7 from experiment are reconstructed in the far-field by multiple signal classification imaging method. The second PERS similarly consists of spiral resonators, which operate at different frequencies. Image of an extended target with a resolution of λ/17 from experiment is reconstructed from the spectra received in the far-field, without the use of the background Green's function. Both simulations and experiments are performed to validate the proposed structures. The sub-wavelength imaging results show that the proposed PERSs can be widely applied in new super-resolution imaging systems.
Autors: Qiang Gao;Xiao-Hua Wang;Bing-Zhong Wang;
Appeared in: IEEE Photonics Journal
Publication date: Feb 2018, volume: 10, issue:1, pages: 1 - 11
Publisher: IEEE
 
» Faraday Rotation Correction for SMAP and Soil Moisture Retrieval
Abstract:
Faraday rotation can be significant at L-band and needs to be considered in remote sensing from space using the spectrum window at 1.413 GHz protected for passive observations. This is especially so for a conical scanner such as SMAP because the variation of the rotation angle with position around the scan is of the same order of magnitude as the change with geographic position as the sensor travels in its orbit around the globe. Furthermore, the angle retrieved in situ by the radiometer is particularly noisy over land raising additional issues for remote sensing of soil moisture. Research is reported here assessing the magnitude of the problem and suggesting an approach for treating Faraday rotation in the context of remote sensing of soil moisture with a conical scanner like SMAP.
Autors: David M. Le Vine;Saji Abraham;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Feb 2018, volume: 56, issue:2, pages: 655 - 668
Publisher: IEEE
 
» Fast Acquirable Long-Range Measurement With Frequency-Swept Probe BOTDA
Abstract:
We propose a novel BOTDA that can measure a BFS change appearing on a time axis with a single-shot measurement by using a frequency-swept probe pulse. The proposed method employs a very simple laser control and detection system, without precise test light frequency control, and with an oscilloscope. We demonstrate a fast BFS distribution measurement that is completed within 3.4 s with ±1.2 MHz BFS accuracy over a 40 km range with a 10 m spatial resolution and without averaging. And only 10 times averaging achieved a 1.0 MHz BFS accuracy for an 80 km measurement.
Autors: Chihiro Kito;Hiroshi Takahashi;Kunihiro Toge;Tetsuya Manabe;
Appeared in: Journal of Lightwave Technology
Publication date: Feb 2018, volume: 36, issue:4, pages: 885 - 890
Publisher: IEEE
 
» Fast Analysis of Time Interval Error in Current-Mode Drivers
Abstract:
An efficient approach for modeling of time interval error (TIE) due to noise in power delivery networks (PDNs), for current-mode (CM) driver circuits, is presented. Semianalytical expressions relating the PDN noise and TIE are developed based on midpoint delays of the rising and falling edges of the differential signal. The validating examples with CM driver circuits designed in various technologies comparing both the proposed and conventional approaches demonstrate a significant speedup using the proposed approach.
Autors: Jai Narayan Tripathi;Ramachandra Achar;Rakesh Malik;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Feb 2018, volume: 26, issue:2, pages: 367 - 377
Publisher: IEEE
 
» Fast and High-Resolution Simultaneous Measurement of Temperature and Strain Using a Fabry–Perot Interferometer in Polarization-Maintaining Fiber With Laser Diodes
Abstract:
Fast and high-resolution simultaneous measurement of temperature and strain is experimentally demonstrated. A Fabry–Perot interferometer fabricated in a polarization-maintaining fiber has sharp transmission peaks, which are divided into two sets corresponding to the polarization of the transmitted light. The sharp transmission peaks shift in response to changes in temperature and strain, and because the dependence coefficients are different for each set, temperature and strain can be simultaneously measured with high resolution. To read the position of a sharp transmission peak, wavelength sweeping with narrowband light is necessary. By using injection current modulation in a laser diode, high-speed wavelength sweeping and short measuring time are realized. We performed simultaneous measurements with a measurement time of 20 s; measurement resolution of 0.1 C and 0.8  for temperature and strain, respectively; and noise spectral density of 30 n. We further experimentally demonstrated that vibration with an amplitude of 20  and a frequency of 1 Hz and heating at a rate of 0.7 Cs can be simultaneously measured.
Autors: Atsushi Wada;Satoshi Tanaka;Nobuaki Takahashi;
Appeared in: Journal of Lightwave Technology
Publication date: Feb 2018, volume: 36, issue:4, pages: 1011 - 1017
Publisher: IEEE
 
» Fast Decoding of Expander Codes
Abstract:
Expander codes are Tanner codes defined on sparse graphs that have good expansion properties. Sipser and Spielman (1996) showed that there is a linear-time decoding algorithm for expander codes when the vertex expansion is at least 3/4 and the number of errors corrected is a constant fraction of the code length. Later, Feldman et al. (2007) gave a decoding algorithm that allows the expansion to be 2/3 + 1/(3c), where is the left degree of the underlying bipartite graph, at the expense of polynomial-time decoding complexity. Recently, Viderman (2013) further improved the expansion parameter to , and the decoding algorithm runs in linear time. These results are for expander codes whose inner codes are parity-check codes. By using stronger inner codes, Chilappagari et al. (2010) showed that there is a linear-time decoding algorithm for every vertex expansion greater than 1/2. In this paper, it is shown that for every vertex expansion, there is a linear-time decoding algorithm for expander codes (using inner codes with minimum distance depending on the vertex expansion), and that the number of errors corrected is a constant fraction of the code length.
Autors: Michael Dowling;Shuhong Gao;
Appeared in: IEEE Transactions on Information Theory
Publication date: Feb 2018, volume: 64, issue:2, pages: 972 - 978
Publisher: IEEE
 
» Fast Discrimination of Transformer Magnetizing Current From Internal Faults: An Extended Kalman Filter-Based Approach
Abstract:
Differential protection is the most common type of protection in power transformers. However, inrush current due to transformer energization may appear as fault current to the protective relay, causing a false trip of the transformer. Therefore, discrimination of the transformer inrush current from internal faults is necessary to improve the security of the protection scheme. In this paper, a new method for discrimination of the transformer inrush current from an internal fault current is proposed. First, the nonlinear state-space model of a real single-phase transformer is derived, which incorporates the nonlinear phenomena of hysteresis and magnetic saturation. Based on the derived model, an Extended Kalman Filter (EKF) is used for estimation of the primary winding current. A residual signal is defined as the difference between the measured and estimated currents. When a healthy transformer is energized, the EKF perfectly estimates the primary winding current and, hence, the residual signal is almost zero. However, when the transformer is faulty, the EKF cannot effectively estimate the current due to the existing large model mismatches. Consequently, a large residual signal is created. The superiorities of the proposed algorithm are demonstrated using different experimental scenarios.
Autors: Farshid Naseri;Zahra Kazemi;Mohammad Mehdi Arefi;Ebrahim Farjah;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Feb 2018, volume: 33, issue:1, pages: 110 - 118
Publisher: IEEE
 
» Fast Randomized Singular Value Thresholding for Low-Rank Optimization
Abstract:
Rank minimization can be converted into tractable surrogate problems, such as Nuclear Norm Minimization (NNM) and Weighted NNM (WNNM). The problems related to NNM, or WNNM, can be solved iteratively by applying a closed-form proximal operator, called Singular Value Thresholding (SVT), or Weighted SVT, but they suffer from high computational cost of Singular Value Decomposition (SVD) at each iteration. We propose a fast and accurate approximation method for SVT, that we call fast randomized SVT (FRSVT), with which we avoid direct computation of SVD. The key idea is to extract an approximate basis for the range of the matrix from its compressed matrix. Given the basis, we compute partial singular values of the original matrix from the small factored matrix. In addition, by developping a range propagation method, our method further speeds up the extraction of approximate basis at each iteration. Our theoretical analysis shows the relationship between the approximation bound of SVD and its effect to NNM via SVT. Along with the analysis, our empirical results quantitatively and qualitatively show that our approximation rarely harms the convergence of the host algorithms. We assess the efficiency and accuracy of the proposed method on various computer vision problems, e.g., subspace clustering, weather artifact removal, and simultaneous multi-image alignment and rectification.
Autors: Tae-Hyun Oh;Yasuyuki Matsushita;Yu-Wing Tai;In So Kweon;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Feb 2018, volume: 40, issue:2, pages: 376 - 391
Publisher: IEEE
 
» Fast Rerouting Against Multi-Link Failures Without Topology Constraint
Abstract:
Multi-link failures may incur heavy packet loss and degrade the network performance. Fast rerouting has been proposed to address this issue by enabling routing protections. However, the effectiveness and efficiency issues of fast rerouting are not well addressed. In particular, the protection performance of existing approaches is not satisfactory even if the overhead is high, and topology constraints need to be met for the approaches to achieve a complete protection. To optimize the efficiency, we first answer the question that whether label-free routing can provide a complete protection against arbitrary multi-link failures in any networks. We propose a model for interface-specific-routing which can be seen as a general label-free routing. We analyze the conditions under which a multi-link failure will induce routing loops. And then, we present that there exist some networks in which no interface-specific-routing (ISR) can be constructed to protect the routing against any -link failures (). Then, we propose a tunneling on demand (TOD) approach, which covers most failures with ISR, and activate tunneling only when failures cannot be detoured around by ISR. We develop algorithms to compute ISR properly so as to minimize the number of activated tunnels, and compute the protection tunnels if necessary. We prove that TOD can protect routing against any single-link failures and dual-link failures. We evaluate TOD by simulations with real-world topologies. The results show that TOD can achieve a near 100% protection ratio with small tunneling overhead for multi-link failures, making a better tradeoff than the state-of-the-art label-based approaches.
Autors: Yuan Yang;Mingwei Xu;Qi Li;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Feb 2018, volume: 26, issue:1, pages: 384 - 397
Publisher: IEEE
 
» Fast Scheduling of Robot Teams Performing Tasks With Temporospatial Constraints
Abstract:
The application of robotics to traditionally manual manufacturing processes requires careful coordination between human and robotic agents in order to support safe and efficient coordinated work. Tasks must be allocated to agents and sequenced according to temporal and spatial constraints. Also, systems must be capable of responding on-the-fly to disturbances and people working in close physical proximity to robots. In this paper, we present a centralized algorithm, named “Tercio,” that handles tightly intercoupled temporal and spatial constraints. Our key innovation is a fast, satisficing multi-agent task sequencer inspired by real-time processor scheduling techniques and adapted to leverage a hierarchical problem structure. We use this sequencer in conjunction with a mixed-integer linear program solver and empirically demonstrate the ability to generate near-optimal schedules for real-world problems an order of magnitude larger than those reported in prior art. Finally, we demonstrate the use of our algorithm in a multirobot hardware testbed.
Autors: Matthew C. Gombolay;Ronald J. Wilcox;Julie A. Shah;
Appeared in: IEEE Transactions on Robotics
Publication date: Feb 2018, volume: 34, issue:1, pages: 220 - 239
Publisher: IEEE
 
» Fast Smoke Detection for Video Surveillance Using CUDA
Abstract:
Smoke detection is a key component of disaster and accident detection. Despite the wide variety of smoke detection methods and sensors that have been proposed, none has been able to maintain a high frame rate while improving detection performance. In this paper, a smoke detection method for surveillance cameras is presented that relies on shape features of smoke regions as well as color information. The method takes advantage of the use of a stationary camera by using a background subtraction method to detect changes in the scene. The color of the smoke is used to assess the probability that pixels in the scene belong to a smoke region. Due to the variable density of the smoke, not all pixels of the actual smoke area appear in the foreground mask. These separate pixels are united by morphological operations and connected-component labeling methods. The existence of a smoke region is confirmed by analyzing the roughness of its boundary. The final step of the algorithm is to check the density of edge pixels within a region. Comparison of objects in the current and previous frames is conducted to distinguish fluid smoke regions from rigid moving objects. Some parts of the algorithm were boosted by means of parallel processing using compute unified device architecture graphics processing unit, thereby enabling fast processing of both low-resolution and high-definition videos. The algorithm was tested on multiple video sequences and demonstrated appropriate processing time for a realistic range of frame sizes.
Autors: Alexander Filonenko;Danilo Cáceres Hernández;Kang-Hyun Jo;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Feb 2018, volume: 14, issue:2, pages: 725 - 733
Publisher: IEEE
 
» Fast Spatial Resolution Analysis of Quadratic Penalized Least-Squares Image Reconstruction With Separate Real and Imaginary Roughness Penalty: Application to fMRI
Abstract:
Penalized least-squares iterative image reconstruction algorithms used for spatial resolution-limited imaging, such as functional magnetic resonance imaging (fMRI), commonly use a quadratic roughness penalty to regularize the reconstructed images. When used for complex-valued images, the conventional roughness penalty regularizes the real and imaginary parts equally. However, these imaging methods sometimes benefit from separate penalties for each part. The spatial smoothness from the roughness penalty on the reconstructed image is dictated by the regularization parameter(s). One method to set the parameter to a desired smoothness level is to evaluate the full width at half maximum of the reconstruction method’s local impulse response. Previous work has shown that when using the conventional quadratic roughness penalty, one can approximate the local impulse response using an FFT-based calculation. However, that acceleration method cannot be applied directly for separate real and imaginary regularization. This paper proposes a fast and stable calculation for this case that also uses FFT-based calculations to approximate the local impulse responses of the real and imaginary parts. This approach is demonstrated with a quadratic image reconstruction of fMRI data that uses separate roughness penalties for the real and imaginary parts.
Autors: Valur T. Olafsson;Douglas C. Noll;Jeffrey A. Fessler;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Feb 2018, volume: 37, issue:2, pages: 604 - 614
Publisher: IEEE
 

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  2016:   January     February     March     April     May     June     July     August     September     October     November     December    

  2015:   January     February     March     April     May     June     July     August     September     October     November     December    

  2014:   January     February     March     April     May     June     July     August     September     October     November     December    

  2013:   January     February     March     April     May     June     July     August     September     October     November     December    

  2012:   January     February     March     April     May     June     July     August     September     October     November     December    

  2011:   January     February     March     April     May     June     July     August     September     October     November     December    

  2010:   January     February     March     April     May     June     July     August     September     October     November     December    

  2009:   January     February     March     April     May     June     July     August     September     October     November     December    

 
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