Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 4

» Automotive Electrical and Electronic Architecture Security via Distributed In-Vehicle Traffic Monitoring
Abstract:
Due to the growing interconnectedness and complexity of in-vehicle networks, in addition to safety, security is becoming an increasingly important topic in the automotive domain. In this paper, we study techniques for detecting security infringements in automotive electrical and electronic (E/E) architectures. Toward this we propose in-vehicle network traffic monitoring to detect increased transmission rates of manipulated message streams. Attacks causing timing violations can disrupt safety-critical functions and have severe consequences. To reduce costs and prevent single points of failure, our approach enables an automatic distribution of detection tasks among selected E/E architecture components, such as a subset of electronic control units. First, we analyze a concrete E/E system architecture to determine the communication parameters and properties necessary for detecting security attacks. These are then used for a parametrization of the corresponding detection algorithms and the distribution of attack detection tasks. We use a lightweight message monitoring method and optimize the placement of detection tasks to ensure a full-coverage of the E/E system architecture and a timely detection of an attack.
Autors: Peter Waszecki;Philipp Mundhenk;Sebastian Steinhorst;Martin Lukasiewycz;Ramesh Karri;Samarjit Chakraborty;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Nov 2017, volume: 36, issue:11, pages: 1790 - 1803
Publisher: IEEE
 
» Average Error Rates and Achievable Capacity in Large Office Indoor Wireless Environments
Abstract:
Performance of common digital modulation techniques is analyzed over indoor wireless environments modeled through the recently proposed joint fading and two-path shadowing (JFTS) channel model. Mathematically tractable expressions for the instantaneous signal-to-noise ratio statistics, average bit error rates, and achievable channel cutoff rates are derived. Analytical results are used to: 1) investigate the impact of different JFTS model parameters and different modulation techniques on bit error rates and cutoff rates and 2) demonstrate how the JFTS channel model affects system performance in comparison with conventional empirical channel models. Finally simulation results are used to corroborate this analysis and evaluate the usefulness of such an analysis.
Autors: Indrakshi Dey;Geoffrey G. Messier;Sebastian Magierowski;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4955 - 4965
Publisher: IEEE
 
» Axial Position Estimation of Conical Shaped Motors for Aerospace Traction Applications
Abstract:
This paper is concerned with the use of conical induction machines. Such machines are extremely valuable when apart from the rotational torque output; an axial translation of the rotor is also required. The inherent attraction between the stator and rotor of any machine combined with the geometry of a conical machine will provide the required axial movement. However, when applied to aerospace applications, where reliability is very important, then full monitoring of the axial position is required. In this paper, an innovative approach aimed at monitoring and controlling the axial translation of a conical induction machine is proposed and investigated. In order to increase the system reliability and also decrease component count as demanded by the application, the methodology is a sensor-less technique based on an innovative variant of the high-frequency injection approach. In this paper, the technique has been fully investigated and experimentally validated on a purposely built instrumented test-rig.
Autors: Sara Roggia;Francesco Cupertino;Chris Gerada;Michael Galea;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5405 - 5414
Publisher: IEEE
 
» Axial Unbalanced Magnetic Force in a Permanent Magnet Motor Due to a Skewed Magnet and Rotor Eccentricities
Abstract:
We investigate the effect of a skewed permanent magnet (PM) with overhang on the axial unbalanced magnetic force (UMF) of a PM motor, especially in the presence of static and dynamic eccentricities of a rotor. We derive the mathematical equations of the axial UMF acting on PM motor due to the skewed PM with overhang and rotor eccentricities. We develop a 3-D finite-element model of the PM motor, not only to verify the frequency components of the proposed equations but also to determine the amplitude of the axial UMF. Further, we develop an experimental setup to measure the axial UMF caused by a skewed PM with overhang and rotor eccentricities. We confirm that the skewed PM with overhang generates an axial UMF with the harmonic of the least common multiple of pole and slot numbers. In addition, the static and dynamic eccentricities with the interaction of the skewed PM and overhang generate the axial UMF with the pole harmonics and slot harmonics, respectively.
Autors: Chi Ho Kang;Kyung Jin Kang;Jeong Yong Song;Young Jin Cho;Gun Hee Jang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Bandwidth for the Equivalent Circuit Model in Square-Loop Frequency Selective Surfaces
Abstract:
This paper presents the results of a study, implemented for the equivalent circuit model (ECM), concerning the bandwidth in square-loop frequency-selective surfaces (FSSs). For the square-loop ECM, there is no formulation to quantify the effects of dielectric supporting layers, geometric features, and incident wave properties on the FSS bandwidth. Hence, it is not possible to control or evaluate the bandwidth of the FSS in the design from the knowledge of these parameters. In this paper, we addressed this issue using the ECM as an analysis method. In the first part of this study, we considered the square-loop FSS with thin dielectric supporting layers, where the bandwidth was expressed as a function of geometric parameters, incidence angle, and polarization of the incident wave as well as a factor that takes into account the effective permittivity of the dielectric support. Particle swarm optimization method was used to synthesize square-loop FSSs via the ECM with a specific resonant frequency and bandwidth requirements. In the second part, the behavior of bandwidth as a function of dielectric thickness was obtained by using a matrix cascading technique (MCT), implemented with ECM and a model for the dielectric effective permittivity. This approach takes into account the modifications on bandwidth due to multiple reflections on dielectric boundaries and allows calculating its value for any dielectric thickness and configuration. It is remarkable the low computational cost and acceptable accuracy obtained with the proposed approaches. All simulation results using ECM and MCT were compared with Ansys-HFSS commercial software simulations.
Autors: Mario A. Rodriguez Barrera;Walter Pereira Carpes;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5932 - 5939
Publisher: IEEE
 
» Baromagnetic Effect in the Hexagonal Mn3Sn System
Abstract:
The magnetic behaviors influenced by the hydrostatic pressure in the polycrystalline hexagonal Mn3Sn intermetallic compound are briefly reported. The crystalline structure of Mn3Sn is determined to be hexagonal with lattice parameters (6) Å and (6) Å by means of the powder X-ray diffraction and the subsequent Rietveld refinement. Two distinct transitions can be observed from the M(T) curves in the range of 150-450 K. During the cooling process, Mn3Sn sample first changes into a triangular antiferromagnetic (AFM) state with weak ferromagnetism at the Néel temperature of ~412 K, and then, it further transforms to a spiral AFM spin arrangement over a broad temperature range from 260 to 180 K at ambient pressure. With the application or the increase of hydrostatic pressures, this triangular to spiral AFM transition occurs at higher temperatures, while the magnetization of triangular AFM phase increases significantly. Such a phenomenon can be explained by the fact that the hydrostatic pressure compresses the sample and shortens the Mn–Mn separation, and thus, the moments of Mn will deviate from their ideal 120° configuration to their easy axis in the basal plane. The variations of transition temperature and maximum magnetization with applied hydrostatic pressure confirm the incremental instability of the triangular AFM arrangement under pressure.
Autors: K. Xu;Y. L. Zhang;Y. M. Cao;X. J. He;Z. Li;S. X. Wei;Y. R. Kang;C. Jing;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Base Station-Side Rate Estimation for Threshold-Based Feedback, and Design Implications in Multi-User OFDM Systems
Abstract:
Rate adaptation and scheduling are essential in ensuring that contemporary orthogonal frequency division multiplexing systems achieve high downlink spectral efficiencies. They depend upon reduced feedback schemes to efficiently feedback channel state information from the users to the base station (BS). In the popular threshold-based quantized feedback scheme, a user feeds back to the BS the quantized value of the signal-to-noise ratio for each subchannel. For this scheme, we derive a novel, throughput-optimal discrete rate adaptation (TORA) policy, which enables a system designer to reduce the feedback overhead. We present it in closed form for different multi-antenna diversity modes for the exponentially correlated subchannel gains model. We also develop a computationally simpler suboptimal variant of it. We derive an insightful lower bound for the fading- and user location-averaged throughput gain achieved by TORA over conventional rate adaptation for 1-bit feedback. We present extensive results to benchmark the system-level performance of TORA for different numbers of feedback bits and modulation and coding schemes available at the BS, and various schedulers, quantizers, and multi-antenna modes.
Autors: Vineeth Kumar;Neelesh B. Mehta;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7634 - 7645
Publisher: IEEE
 
» Basic Characterization of Magnetocoated Wire Fabricated Using Spray Method
Abstract:
Recently, there has been an increase in the demand for high-efficiency miniature electronic equipment such as personal computers. Therefore, using high drive frequencies and reducing copper loss have become important in meeting the demand. In this paper, we propose the use of magnetocoated wires (MCWs) for coil windings fabricated using the spray method. MCW coils reduce the resistance due to the proximity effect because a magnetic layer leads a magnetic field. As a result, the resistances of the copper wire (COW) and MCW coils at the frequency MHz are 668 and 447 , respectively, which show a reduction of 33% from resistance of COW to MCW. The resistances of the MCW coils at the frequency kHz and the current A decreased by 10% compared with the resistances of the COW. The temperature increment of the MCW coils decreased by 5 °C compared with that of COW. This was because MCWs decrease the ac resistance of coils. The magnetic saturation was examined in detail using the finite-element method from the measured value of complex permeability. From the calculated magnetic field and measured magnetization curve, we show the absence of magnetic saturation in coils of nine turns.
Autors: Yasuyuki Konno;Tatsuya Yamamoto;Yuki Chai;Dobashi Tomoya;Yinggang Bu;Tsutomu Mizuno;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Batteryless Hall Sensor Operated by Energy Harvesting From a Single Wiegand Pulse
Abstract:
We operated a Hall sensor using energy harvested from a magnetic wire. A batteryless sensor is expected to be a key device for the Internet of Things. Magnetization reversal in magnetic wires with bistable magnetization states induces a pulse voltage in a pickup coil. The amplitude of the voltage is independent of the applied field frequency, down to zero. This fast magnetization reversal is accompanied by a large Barkhausen jump, which has been known as the Wiegand effect. Electricity generation using this effect, obtained with twisted FeCoV magnetic wires, was studied. The energy obtained as a single pulse voltage was 600 nJ. The Hall sensor operated with this pulse voltage. The pulse power of 0.88 V/1.3 mA was applied to the Hall sensor. The Hall voltage was proportional to the sensing magnetic field of 50–300 mT.
Autors: Yasushi Takemura;Naoya Fujinaga;Akitoshi Takebuchi;Tsutomu Yamada;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Bayesian Approach for Distribution System State Estimation With Non-Gaussian Uncertainty Models
Abstract:
To deal with the increasing complexity of distribution networks that are experiencing important changes, due to the widespread installation of distributed generation and the expected penetration of new energy resources, modern control applications must rely on an accurate picture of the grid status, given by the distribution system state estimation (DSSE). The DSSE is required to integrate all the available information on loads and generators power exchanges (pseudomeasurements) with the real-time measurements available from the field. In most cases, the statistical behavior of the measured and pseudomeasured quantities cannot be approximated by a Gaussian distribution. For this reason, it is necessary to design estimators that are able to use measurements and forecast data on power flows that can show a non-Gaussian behavior. In this paper, a DSSE algorithm based on Bayes's rule, conceived to perfectly match the uncertainty description of the available input information, is presented. The method is able to correctly handle the measurement uncertainty of conventional and synchronized measurements and to include possible correlation existing between the pseudomeasurements. Its applicability to medium voltage distribution networks and its advantages, in terms of accuracy of both estimated quantities and uncertainty intervals, are demonstrated.
Autors: Paolo Attilio Pegoraro;Andrea Angioni;Marco Pau;Antonello Monti;Carlo Muscas;Ferdinanda Ponci;Sara Sulis;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 2957 - 2966
Publisher: IEEE
 
» Bayesian Data Combination for the Estimation of Ionospheric Effects in SAR Interferograms
Abstract:
The ionospheric propagation path delay is a major error source in synthetic aperture radar (SAR) interferograms and, therefore, has to be estimated and corrected. Various methods can be used to extract different kinds of information about the ionosphere from SAR images, with different accuracies. This paper presents a general technique, based on a Bayesian inverse problem, that combines various information sources in order to increase the estimation accuracy, and thus the correction. A physically realistic fractal modeling of the ionosphere turbulence and a data-based estimation of the model parameters allow the avoidance of arbitrary filtering windows and coefficients. To test the technique, the differential ionospheric phase screen was estimated by combining the split-spectrum method with the azimuth mutual shifts between interferometric pair images. This combination is convenient since it can benefit from the strengths of both sources: range and azimuth variations from the split-spectrum method and small-scale azimuth variations from more sensitive azimuth shifts. Therefore, the two methods can recover the long and short wavelength components of the ionospheric phase screen, respectively. A theoretical comparison between the Faraday rotation method and the split-spectrum method is also reported. For the use in the combination, precedence was then given to the split-spectrum method because of the comparable precision level, lower susceptibility to biases, and wider applicability. Finally, Advanced Land Observing Satellite Phased Array type L-band SAR L-band images are used to show how the combined result is more accurate than that obtained with the simple split-spectrum method.
Autors: Giorgio Gomba;Francesco De Zan;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6582 - 6593
Publisher: IEEE
 
» Bayesian-Inference-Based Voltage Dip State Estimation
Abstract:
Voltage dip state estimation (VDSE) tries to estimate the voltage dip characteristics at nonmonitored buses from measured voltage dip values at monitored buses. In this paper, the VDSE is addressed through the method based on Bayesian inference. A priori including the fault position among other grid conditions is used to estimate the residual voltage at each bus based on the measurement quantities, including their uncertainties. The dip duration is calculated with the time setting of protection system incorporating the uncertainties due to dip detection algorithm of the root mean square values. The proposed method has been applied to the IEEE 13-bus and IEEE 123-bus distribution test systems for multiple simulation scenarios, such as with or without distributed generation and different types of faults. The simulation results show good observability of the network.
Autors: Gu Ye;Yu Xiang;Michiel Nijhuis;Vladimir Cuk;J. F. G. Cobben;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 2977 - 2987
Publisher: IEEE
 
» Beamwidth Properties of Endfire 1-D Leaky-Wave Antennas
Abstract:
In this communication, the beam properties of one-dimensional leaky-wave antennas (1-D LWAs) are explored when the LWA scanning approaches endfire. By increasing the phase constant beyond the ordinary endfire condition, smaller beamwidths can be produced at the expense of increased sidelobe level (SLL). This tradeoff is quantified here for the first time for endfire 1-D LWAs. Simple CAD formulas are also proposed that describe accurately the beamwidth and SLL for 1-D LWAs operating at endfire. This communication is conducted for different radiation efficiencies covering most practical ranges. A closed-form expression for the beamwdith of a 1-D LWA with an infinite aperture is also given, in which case there are no sidelobes. These results allow for a better understanding and efficient design of LWAs radiating at endfire.
Autors: Walter Fuscaldo;David R. Jackson;Alessandro Galli;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6120 - 6125
Publisher: IEEE
 
» Belief Propagation and Quickest Detection-Based Cooperative Spectrum Sensing in Heterogeneous and Dynamic Environments
Abstract:
Cognitive radio is one of the enabling technologies considered for the next generation communication systems for many mission-critical applications. In cognitive radio systems, cooperative spectrum sensing is one of the key techniques that can improve reliability and agility. In this paper, a framework that integrates quickest detection and belief propagation is applied to the cooperative spectrum sensing, where the primary user activities are heterogeneous in the space and dynamic in the time. The performance of the proposed scheme is analyzed mathematically. Using numerical simulations, detection performance measured by false alarm rate and average detection delay is obtained for different setups. The results show that the proposed scheme achieves better receiver operational curves than traditional detection method.
Autors: Yifan Wang;Husheng Li;Lijun Qian;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7446 - 7459
Publisher: IEEE
 
» Benchmarking Ensemble Classifiers with Novel Co-Trained Kernel Ridge Regression and Random Vector Functional Link Ensembles [Research Frontier]
Abstract:
Studies in machine learning have shown promising classification performance of ensemble methods employing "perturb and combine" strategies. In particular, the classical random forest algorithm performs the best among 179 classifiers on 121 UCI datasets from different domains. Motivated by this observation, we extend our previous work on oblique decision tree ensemble. We also propose an efficient co-trained kernel ridge regression method. In addition, a random vector functional link network ensemble is also introduced. Our experiments show that our two oblique decision tree ensemble variants and the co-trained kernel ridge regression ensemble are the top three ranked methods among the 183 classifiers. The proposed random vector functional link network ensemble also outperforms all neural network based methods used in the experiments.
Autors: Le Zhang;Ponnuthurai Nagaratnam Suganthan;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 61 - 72
Publisher: IEEE
 
» BER Degradation Detection and Failure Identification in Elastic Optical Networks
Abstract:
Optical connections support virtual links in MPLS-over-optical multilayer networks and therefore, errors in the optical layer impact on the quality of the services deployed on such networks. Monitoring the performance of the physical layer allows verifying the proper operation of optical connections, as well as detecting bit error rate (BER) degradations and anticipating connection disruption. In addition, failure identification facilitates localizing the cause of the failure by providing a short list of potential failed elements and enables self-decision making to keep committed service level. In this paper, we analyze several failure causes affecting the quality of optical connections and propose two different algorithms: one focused on detecting significant BER changes in optical connections, named as BANDO, and the other focused on identifying the most probable failure pattern, named as LUCIDA. BANDO runs inside the network nodes to accelerate degradation detection and sends a notification to the LUCIDA algorithm running on the centralized controller. Experimental measures were carried out on two different setups to obtain values for BER and received power and used to generate synthetic data used in subsequent simulations. Results show significant improvement anticipating maximum BER violation with small failure identification errors.
Autors: Alba P. Vela;Marc Ruiz;Francesco Fresi;Nicola Sambo;Filippo Cugini;Gianluca Meloni;Luca Potì;Luis Velasco;Piero Castoldi;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4595 - 4604
Publisher: IEEE
 
» Bi-Level Approach to Distribution Network and Renewable Energy Expansion Planning Considering Demand Response
Abstract:
This paper presents a bi-level model for distribution network and renewable energy expansion planning under a demand response (DR) framework. The role of DR has recently attracted an increasing interest in power systems. However, previous models have not been completely adapted in order to treat DR on an equal footing. The target of the distribution network and generation planner, modeled through the upper-level problem, is to minimize generation and network investment cost while meeting the demand. This upper-level problem is constrained by the lower-level problem, stressing the importance of integrating DR to time-varying prices into those investment models. The objective function considered for the lower level is the minimization of overall payment faced by the consumers. Using the Karush-Kuhn-Tucker complementarity constraints, the proposed bi-level model is recast as a mixed-integer linear programming problem, which is solvable using efficient off-the-shelf branch-and-cut solvers. Detailed results from an insular case study (La Graciosa, Canary Islands, Spain) are presented.
Autors: Miguel Asensio;Gregorio Muñoz-Delgado;Javier Contreras;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4298 - 4309
Publisher: IEEE
 
» Big Data Analytics for Electric Vehicle Integration in Green Smart Cities
Abstract:
The huge amount of data generated by devices, vehicles, buildings, the power grid, and many other connected things, coupled with increased rates of data transmission, constitute the big data challenge. Among many areas associated with the Internet of Things, smart grid and electric vehilces have their share of this challenge by being both producers and consumers (ie., prosumers) of big data. Electric vehicls can significantly help smart cities to become greener by reducing emissions of the transportation sector and play an important role in green smart cities. In this article, we first survey the data analytics techniques used for handling the big data of smart grid and electric vehicles. The data generated by electric vehicles come from sources that vary from sensors to trip logs. Once this vast amount of data are analyzed using big data techniques, they can be used to develop policies for siting charging stations, developing smart charging algorithms, solving energy efficiency issues, evaluating the capacity of power distribution systems to handle extra charging loads, and finally, determining the market value for the services provided by electric vehicles (i.e., vehicle-to-grid opportunities). This article provides a comprehensive overview of the data analytics landscape on the electric vehicle integration to green smart cities. It serves as a roadmap to the future data analytics needs and solutions for electric vehicle integration to smart cities.
Autors: Boyang Li;Mithat C. Kisacikoglu;Chen Liu;Navjot Singh;Melike Erol-Kantarci;
Appeared in: IEEE Communications Magazine
Publication date: Nov 2017, volume: 55, issue:11, pages: 19 - 25
Publisher: IEEE
 
» Bilayer Pseudospin Junction Transistor (BiSJT) for “Beyond-CMOS” Logic
Abstract:
A novel beyond-CMOS device concept, the Bilayer pseudoSpin Junction Transistor (BiSJT), is proposed. Like the previously proposed Bilayer pseudoSpin FET (BiSFET), the BiSJT is motivated by the possibility of interlayer electron–hole exciton condensation in bilayer 2-D material systems, and could provide switching energies of a few 10 s of zJ, orders of magnitude below even end-of-the-roadmap CMOS. The BiSJT is, however, current-controlled, and may allow for simpler device design, smaller device area, and more flexible gate design.
Autors: Xuehao Mou;Leonard F. Register;Allan H. MacDonald;Sanjay K. Banerjee;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4759 - 4762
Publisher: IEEE
 
» Biocompatible Nanovehicle With Adjustable Magnetic Properties
Abstract:
In the frame of this paper, the synthesis of self-assembled magnetic and biocompatible nanovehicles movable in aqueous solutions by a magnetic field gradient is presented. The systems consist of a mesoporous silicon template and encapsulated iron oxide nanostructures, both materials known to be biocompatible. Two routes are applied to produce iron oxide nanostructures embedded within porous silicon. First, readily synthesized superparamagnetic iron oxide nanoparticles (NPs) are infiltrated into the pores. The second attempt is the chemical deposition of iron oxide structures inside the PSi templates. Concerning the adjustability of the magnetic properties of the system the loading procedure of the PSi with iron oxide NPs will be elucidated in detail as well as the growth of iron oxide structures within the pores. An assessment of the iron oxide deposition dependent on the template and the chemical parameters as well as of the magnetic properties in dependence on the particle size and template morphology of the nanocomposite will be presented. A further approach is the transition from a magnetite to the stable hematite phase by heat treatment of the specimens. A sufficient filling leading to a magnetization high enough for the movement of the nanovehicles within aqueous surroundings (e.g., body fluid) by magnetic field gradients could be reached easily.
Autors: Petra Granitzer;Klemens Rumpf;Peter Poelt;Michael Reissner;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Bioluminescence Tomography Based on Gaussian Weighted Laplace Prior Regularization for In Vivo Morphological Imaging of Glioma
Abstract:
Bioluminescence tomography (BLT) is a powerful non-invasive molecular imaging tool for in vivo studies of glioma in mice. However, because of the light scattering and resulted ill-posed problems, it is challenging to develop a sufficient reconstruction method, which can accurately locate the tumor and define the tumor morphology in three-dimension. In this paper, we proposed a novel Gaussian weighted Laplace prior (GWLP) regularization method. It considered the variance of the bioluminescence energy between any two voxels inside an organ had a non-linear inverse relationship with their Gaussian distance to solve the over-smoothed tumor morphology in BLT reconstruction. We compared the GWLP with conventional Tikhonov and Laplace regularization methods through various numerical simulations and in vivo orthotopic glioma mouse model experiments. The in vivo magnetic resonance imaging and ex vivo green fluorescent protein images and hematoxylin-eosin stained images of whole head cryoslicing specimens were utilized as gold standards. The results demonstrated that GWLP achieved the highest accuracy in tumor localization and tumor morphology preservation. To the best of our knowledge, this is the first study that achieved such accurate BLT morphological reconstruction of orthotopic glioma without using any segmented tumor structure from any other structural imaging modalities as the prior for reconstruction guidance. This enabled BLT more suitable and practical for in vivo imaging of orthotopic glioma mouse models.
Autors: Yuan Gao;Kun Wang;Shixin Jiang;Yuhao Liu;Ting Ai;Jie Tian;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2343 - 2354
Publisher: IEEE
 
» Biomechanical Reactions of Exoskeleton Neurorehabilitation Robots in Spastic Elbows and Wrists
Abstract:
Spasticity is an important factor in designing wearable and lightweight exoskeleton neurorehabilitation robots. The proposed study evaluates biomechanical reactions of an exoskeleton robot to spasticity and establishes relevant guidelines for robot design. A two-axis exoskeleton robot is used to evaluate a group of 20 patients post-stroke with spastic elbow and/or wrist joints. All subjects are given isokinetic movements at various angular velocities within the capable range of motion for both joints. The resistance torque and corresponding angular position at each joint are recorded continuously. Maximal resistance torques caused by low (modified Ashworth scale (MAS) 0, 1), intermediate (MAS 1+), and high (MAS 2 and 3) grade spasticity were 3.68 ± 2.42, 5.94 ± 2.55, and 8.25 ± 3.35 Nm for the elbow flexor (, between each grades) and 4.23 ± 1.75, 5.68 ± 1.96, and 5.44 ± 2.02 Nm for the wrist flexor (, for low versus intermediate, low versus high grade spasticity). The angular velocity did not significantly influence maximal resistance torque in either joint. The catch occurred more quickly at higher velocities for low and intermediate elbow flexor spasticity (). Spasticity caused considerable resistance to the robots during mechanically actuated movements. The resistance range according to the degree of spasticity should be considered when designing practical neurorehabilitation robots.
Autors: Hyung Seok Nam;Sukgyu Koh;Yoon Jae Kim;Jaewon Beom;Woo Hyung Lee;Shi-Uk Lee;Sungwan Kim;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2196 - 2203
Publisher: IEEE
 
» Bistatic Coherent Polarimetric Scattering of Randomly Corrugated Layered Snow Surfaces
Abstract:
We analyzed the bistatic coherent scattering mechanism of a layered randomly corrugated snow surface, a typical rough surface, with radar polarimetry theory whose scattering matrix was obtained from a physical-based full wave numerical simulation by solving Maxwell's equations. The effects of top–bottom structure, layer thickness, frequency response, and angular dependence are illustrated by observing stokes vector, coherence matrix, and Kennaugh matrix. The results show that top–bottom structure and snow thickness change the state of polarization depending on frequency and bistatic configuration. Analyzing the bistatic polarimetric scattering mechanism based on numerical simulation and the polarimetry theory can be an efficacious source for configuring bistatic observation to detect and classify radar targets. For example, observation at a specular angle of 55° comparatively contains more information on surface structure, and wave entropy is more preferable over degree of polarization as a snow surface structure estimator. Moreover, parameters from Kennaugh decomposition can indicate top–bottom structure better than layer thickness. Last but not the least, we also found that the symmetry assumption commonly used in classical theory of polarization is generally not valid for bistatic observation, and the combination of some Huynen parameters can be reasonably good indicators of snow surface structural symmetry. We expect this paper to offer deeper understanding of the coherent imaging of snow surfaces and to help design a novel bistatic imaging system for layered snow surface.
Autors: Yu Liu;Kun-Shan Chen;Peng Xu;Zhao-Liang Li;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 4721 - 4739
Publisher: IEEE
 
» Bit-Error Ratio Performance Improvement Using Iterative Decoding for Polybinary-Shaped Super-Nyquist Wavelength Division Multiplexed Signals
Abstract:
In super-Nyquist wavelength division multiplexed (WDM) systems with frequency spacing smaller than the signal baudrate, the maximum-likelihood (ML) decoder in the receiver is usually introduced to compensate for intersymbol interference due to tight spectral filtering, such as polybinary shaping. After the ML decoder, symbol errors tend to propagate, causing excess continuous errors. Considering that forward error correction (FEC) is commonly introduced, the excess continuous errors degrade bit-error ratio (BER) performance after FEC, so-called post-FEC BER. In order to suppress the performance degradation, we introduce iterative decoding between the first ML decoder for polybinary shaping and the second FEC decoder in the receiver. First, we calculate BER characteristics of polybinary-shaped super-Nyquist WDM quadrature phase-shift keying (QPSK) signals. The results show that iterative decoding is effective for improving post-FEC BER performance. A lager pre-FEC BER threshold for post-FEC BER <; 10-5 is obtained in super-Nyquist WDM case than in the Nyquist WDM case, although a higher signal-to-noise ratio (SNR) is required. Next, we measure the BER characteristics of three-channel duobinary-shaped super-Nyquist WDM 12.5-Gbaud dual-polarization QPSK signals. The iterative decoding reduces the optical SNR penalty by 0.8 dB. A larger pre-FEC BER threshold of 3.1 × 10-2 is obtained in the duobinary-shaped super-Nyquist WDM case, compared with the threshold of 2.2 × 10-2 in the Nyquist WDM case.
Autors: Shuai Yuan;Koji Igarashi;Takehiro Tsuritani;Itsuro Morita;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4605 - 4612
Publisher: IEEE
 
» Blending Communities and Team-Based Learning in a Programming Course
Abstract:
In recent years, engineering education teachers have needed to incorporate technology-supported collaboration to enhance learning. Implementing these activities requires course redesign, which must be meticulous for their full potential to be reached. This can require a lot of work for first time users, which can be a barrier to implementation. Educational design patterns alleviate this burden by facilitating new course design with practices demonstrated to promote student engagement. This paper reports on the redesign of an introductory programming course and its experimental evaluation. The redesign was based on the community of inquiry learning framework (CoL), using design patterns from online Web communities and team-based learning (TBL). The evaluation included 562 students, 117 of them randomly assigned to two different experimental groups. One group used a CoL approach, and the other a blended TBL and CoL methodology. The remaining students were assigned to control groups. Results showed that students in the experimental groups outperformed those in the control group by the end of the semester, while the experimental CoL and TBL methodology helped students achieve a higher level of understanding in a shorter period of time due to increased participation rates. These data provide empirical evidence of the learning gains offered by online learning communities, and the way in which educational design patterns can facilitate course redesign.
Autors: Ignacio Cabrera;Jorge Villalon;Jorge Chavez;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 288 - 295
Publisher: IEEE
 
» Blending Face Details: Synthesizing a Face Using Multiscale Face Models
Abstract:
Creating realistic 3D face models is a challenging problem in computer graphics because humans are so sensitive to facial abnormalities. The authors propose a method to synthesize a 3D face model using weighted blending of multiscale details from different face models. Using multiscale continuous displacement maps (CDMs), they achieve full correspondences across multiple scales in the parameter space. Their results demonstrate detail transfer across faces with highly different proportions, such as between humans and nonhuman creatures. An artist evaluation also indicated the proposed approach is intuitive and easy to use.
Autors: Seung-Hyun Yoon;John Lewis;Taehyun Rhee;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 65 - 75
Publisher: IEEE
 
» Blind Detection for Spatial Modulation Systems Based on Clustering
Abstract:
In this letter, we propose a pair of blind detectors for spatial modulation multiple-input multiple-output (MIMO) systems based on the clustering concept. Specifically, an improved K-means clustering (KMC) with lower-complexity detector is first proposed to avoid the error floor effects and to reduce the imposed complexity of the conventional KMC detector by employing an initial centroid optimizer. Furthermore, an affinity propagation (AP) detector is developed based on the belief propagation concept, where the number of clusters is not required in the clustering process by using the intelligence information exchanges. The results show that the proposed KMC detector can efficiently avoid the occurrence of error floor effects, while the proposed AP detector is capable of achieving better performance than that of the conventional KMC detector.
Autors: Longfei You;Ping Yang;Yue Xiao;Shi Rong;Deng Ke;Shaoqian Li;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2392 - 2395
Publisher: IEEE
 
» Blind Image Quality Assessment Based on Rank-Order Regularized Regression
Abstract:
Blind image quality assessment (BIQA) aims to estimate the subjective quality of a query image without access to the reference image. Existing learning-based methods typically train a regression function by minimizing the average error between subjective opinion scores and model predictions. However, minimizing average error does not necessarily lead to correct quality rank-orders between the test images, which is a highly desirable property of image quality models. In this paper, we propose a novel rank-order regularized regression model to address this problem. The key idea is to introduce a pairwise rank-order constraint into the maximum margin regression framework, aiming to better preserve the correct perceptual preference. To the best of our knowledge, this is the first attempt to incorporate rank-order constraints into margin-based quality regression model. By combing with a new local spatial structure feature, we achieve highly consistent quality prediction with human perception. Experimental results show that the proposed method outperforms many state-of-the-art BIQA metrics on popular publicly available IQA databases (i.e., LIVE-II, TID2013, VCL@FER, LIVEMD, and ChallengeDB).
Autors: Qingbo Wu;Hongliang Li;Zhou Wang;Fanman Meng;Bing Luo;Wei Li;King N. Ngan;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2490 - 2504
Publisher: IEEE
 
» Blind Stereo Quality Assessment Based on Learned Features From Binocular Combined Images
Abstract:
Quality assessment of stereo images confronts more challenges than its 2D counterparts. Direct use of 2D assessment methods is not sufficient to deal with the challenges of 3D perception. In this paper, an efficient general-purpose no-reference stereo image quality assessment, based on unsupervised feature learning, is presented. The proposed method extracts features without any prior knowledge about the types and levels of distortions. This property enables our method to be adaptable for different applications. The perceived contrast and phase of the binocular combination of original stereo images are utilized to learn individual dictionaries. For each distorted stereo image, two feature vectors are pooled, in a hierarchical manner, over all sparse representation vectors of phase and contrast blocks by their corresponding dictionaries. Performance results of learning a regression model by the features acknowledge the superiority of the proposed method to state-of-the-art algorithms.
Autors: Maryam Karimi;Mansour Nejati;S. M. Reza Soroushmehr;Shadrokh Samavi;Nader Karimi;Kayvan Najarian;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2475 - 2489
Publisher: IEEE
 
» Blocking Predation in Cellular Monopoly Through Non-Linear Spectrum Pricing
Abstract:
Predation refers to the strategic reduction of market price by a monopolist in order to eradicate its potential competitors. We investigate this strategy in a single service provider (SP) dominated cellular network for two different cases: 1) when a new contender attempts to enter into the network and 2) when the contender has already entered and is co-existing with the dominant SP. In both the cases, the sole objective of the predating SP is driving its opponent into losses, therefore discouraging its entry/stay in the market. In this letter, with the assumption that the government is sole provider of bandwidth and infrastructure, we establish the followings: 1) if the spectrum pricing is linear, then the pre-existing SP can always succeed in predation and 2) on the other hand, if government switches to quadratic spectrum pricing, then it is always possible to restrain the predatory behavior.
Autors: Washim Uddin Mondal;Goutam Das;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2464 - 2467
Publisher: IEEE
 
» Blurring the Lines between Memory and Computation
Abstract:
Traditionally, researchers have attempted to address the memory wall by building a deep memory hierarchy. Another solution is to move computation closer to memory, which is often referred to as processing in memory (PIM). Past PIM solutions tried to move computing logic near memory by integrating DRAM with a logic die using 3D stacking. This helps reduce data movement energy and increase bandwidth; however, the functionality and design of memory itself remains unchanged. An even more exciting technology is one that dissolves the line that distinguishes memory from computational units. Nearly three-fourths of silicon in processor and main memory dies is simply to store and access data. Harnessing this silicon area by repurposing it to perform computation can lead to massively parallel computational processing. Furthermore, we naturally save the vast amounts of energy spent in shuffling data back and forth between computational and storage units, and memory bandwidth becomes a meaningless metric.
Autors: Reetuparna Das;
Appeared in: IEEE Micro
Publication date: Nov 2017, volume: 37, issue:6, pages: 13 - 15
Publisher: IEEE
 
» Book Reviews [6 Reviews]
Abstract:
The following books are reviewed: Microgrid-Advanced Control Methods and Renewable Energy System Integration by M. S. Mahmoud; Nanofabrication-Principles to Laboratory Practice by A. Sarangan; Protection of Substation Critical Equipment Against Intentional Electromagnetic Threats by V. Gurevich; Nitride Wide Bandgap Semiconductor Material and Electronic Devices by Y. Hao, J. F. Zhang, and J. C. Zhang; Principles of Lightning Physics by V. Mazur; Atom Probe Tomography-Put Theory into Practice by W. Lefebvre-Ulrikson, F. Vurpillot, and X. Sauvage
Autors: John J. Shea;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Nov 2017, volume: 33, issue:6, pages: 58 - 60
Publisher: IEEE
 
» BOOST: Base Station on-off Switching Strategy for Green Massive MIMO HetNets
Abstract:
We investigate the problem of base station (BS) on-off switching, user association, and power control in a heterogeneous network (HetNet) with massive multiple input multiple output (MIMO), aiming to turn off under-utilized BS’s and maximize the system energy efficiency. With a mixed integer programming problem formulation, we first develop a centralized scheme to derive the near optimal BS on-off switching, which is an iterative framework with proven convergence. We further propose two distributed schemes based on game theory, with a bidding game between users and BS’s, and a pricing game between wireless service provider and users. Both games are proven to achieve a Nash Equilibrium. Simulation studies demonstrate the efficacy of the proposed schemes.
Autors: Mingjie Feng;Shiwen Mao;Tao Jiang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7319 - 7332
Publisher: IEEE
 
» Bounds on Variance for Unimodal Distributions
Abstract:
We show a direct relationship between the variance and the differential entropy for subclasses of symmetric and asymmetric unimodal distributions by providing an upper bound on variance in terms of entropy power. Combining this bound with the well-known entropy power lower bound on variance, we prove that the variance of the appropriate subclasses of unimodal distributions can be bounded below and above by the scaled entropy power. As the differential entropy decreases, the variance is sandwiched between two exponentially decreasing functions in the differential entropy. This establishes that for the subclasses of unimodal distributions, the differential entropy can be used as a surrogate for concentration of the distribution.
Autors: Hye Won Chung;Brian M. Sadler;Alfred O. Hero;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 6936 - 6949
Publisher: IEEE
 
» Branch-Line Couplers With Arbitrary Coupling Value Through the Electrical Length Variation With Fixed Line Impedances
Abstract:
A new method is presented to obtain arbitrary coupling levels of the branch-line couplers through the simple modification of the 3-dB coupler. It is shown that the coupling of the conventional 3-dB branch-line coupler can be adjusted to arbitrary values by varying the electrical length of the branches without changing the impedances. A very wide range of coupling values can easily be obtained using the same line impedances as the conventional 3-dB couplers based on the proposed method.
Autors: Jaegook Lee;Jongchul Lee;Myun-Joo Park;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 968 - 970
Publisher: IEEE
 
» Breakdown Enhancement and Current Collapse Suppression by High-Resistivity GaN Cap Layer in Normally-Off AlGaN/GaN HEMTs
Abstract:
In this letter, a device structure of high-resistivity-cap-layer HEMT (HRCL-HEMT) is developed for normally-off p-GaN gate HEMT toward high breakdown voltage and low current collapse. It demonstrates that the breakdown capability and current collapse of the device were effectively improved due to the introduction of a thick HR-GaN cap layer. The fabricated HRCL-HEMT exhibits a high breakdown voltage of 1020 V at /mm with the substrate grounded. Meanwhile, the dynamic is only 2.4 times the static after off-state stress of 1000 V with the substrate grounded (the OFF to ON switching time interval is set to ).
Autors: Ronghui Hao;Weiyi Li;Kai Fu;Guohao Yu;Liang Song;Jie Yuan;Junshuai Li;Xuguang Deng;Xiaodong Zhang;Qi Zhou;Yaming Fan;Wenhua Shi;Yong Cai;Xinping Zhang;Baoshun Zhang;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1567 - 1570
Publisher: IEEE
 
» Bringing Computation Closer toward the User Network: Is Edge Computing the Solution?
Abstract:
The virtually unlimited available resources and wide range of services provided by the cloud have resulted in the emergence of new cloud-based applications, such as smart grids, smart building control, and virtual reality. These developments, however, have also been accompanied by a problem for delay-sensitive applications that have stringent delay requirements. The current cloud computing paradigm cannot realize the requirements of mobility support, location awareness, and low latency. Hence, to address the problem, an edge computing paradigm that aims to extend the cloud resources and services and enable them to be nearer the edge of an enterprise's network has been introduced. In this article, we highlight the significance of edge computing by providing real-life scenarios that have strict constraint requirements on application response time. From the previous literature, we devise a taxonomy to classify the current research efforts in the domain of edge computing. We also discuss the key requirements that enable edge computing. Finally, current challenges in realizing the vision of edge computing are discussed.
Autors: Ejaz Ahmed;Arif Ahmed;Ibrar Yaqoob;Junaid Shuja;Abdullah Gani;Muhammad Imran;Muhammad Shoaib;
Appeared in: IEEE Communications Magazine
Publication date: Nov 2017, volume: 55, issue:11, pages: 138 - 144
Publisher: IEEE
 
» Broadband Oscillator-Free THz Pulse Generation and Radiation Based on Direct Digital-to-Impulse Architecture
Abstract:
Broadband 0.03–1.1 THz signal generation and radiation are demonstrated based on an oscillator-free direct digital-to-impulse architecture with a 1.9-ps full width at half maximum and 130-GHz 3-dB bandwidth (BW) (200-GHz 10-dB BW) centered at 160 GHz. The radiated pulse achieves a peak pulse effective isotropic-radiated power of 19.2 dBm and peak pulse-radiated power of 2.6 mW. An ON/OFF impulse-shaping technique is introduced and implemented to suppress undesired ringing and to increase dc-to-radiated efficiency. The frequency-comb spectrum of the radiated pulse train with 5.2-GHz repetition rate is measured up to 1.1 THz. At a distance of 4 cm, the measured received SNR at 1 and 1.1 THz is 28 and 22 dB, respectively. A 1.1-THz tone is measured with a 10-dB spectral width of 2 Hz, demonstrating an extremely narrow spectral line width (two parts per trillion). Time-domain picosecond pulses are characterized using a custom femtosecond-laser-based terahertz time-domain spectroscopy system. Coherent spatial combining from two widely spaced chips is demonstrated. It is shown that the starting time of the radiated pulses is locked to the edge of the input digital trigger with a timing jitter of 270 fs. The chip is fabricated in a 130-nm SiGe BiCMOS process technology.
Autors: M. Mahdi Assefzadeh;Aydin Babakhani;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Nov 2017, volume: 52, issue:11, pages: 2905 - 2919
Publisher: IEEE
 
» Broadband Permeability Spectra of Flake-Shaped Ferromagnetic Particle Composites
Abstract:
Broadband permeability spectra of aligned ferromagnetic flakes embedded in a nonmagnetic polymer matrix have been measured using an APC-7 coaxial line within the frequency range 10 MHz–18 GHz. These spectra reveal two well-defined resonance lines. The low-frequency one (sub-GHz range) has previously been attributed to the fundamental vortex translation mode in a multidomain magnetic structure, whereas the high-frequency resonance (beyond 1 GHz) is assigned to the natural spin resonance. A two-level analytical model combining a spin dynamics description including these two contributions at the flake scale and a Maxwell–Garnett mixing rule at the composite scale has been developed and reproduces very satisfactorily the experimental spectra in terms of resonance frequencies, resonance linewidths, and resonance mode amplitudes.
Autors: Z. Raolison;Q. Clément;A.-L. Adenot-Engelvin;N. Malléjac;C. Lefevre;G. Pourroy;F. Boust;N. Vukadinovic;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Bubble Entropy: An Entropy Almost Free of Parameters
Abstract:
Objective: A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy. Bubble Entropy is based on permutation entropy, where the vectors in the embedding space are ranked. We use the bubble sort algorithm for the ordering procedure and count instead the number of swaps performed for each vector. Doing so, we create a more coarse-grained distribution and then compute the entropy of this distribution. Results: Experimental results with both real and synthetic HRV signals showed that bubble entropy presents remarkable stability and exhibits increased descriptive and discriminating power compared to all other definitions, including the most popular ones. Conclusion: The definition proposed is almost free of parameters. The most common ones are the scale factor r and the embedding dimension m . In our definition, the scale factor is totally eliminated and the importance of m is significantly reduced. The proposed method presents increased stability and discriminating power. Significance: After the extensive use of some entropy measures in physiological signals, typical values for their parameters have been suggested, or at least, widely used. However, the parameters are still there, application and dataset dependent, influencing the computed value and affecting the descriptive power. Reducing their significance or eliminating them alleviates the problem, decoupling the method from the data and the application, and eliminating subjective factors.
Autors: George Manis;Md Aktaruzzaman;Roberto Sassi;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2711 - 2718
Publisher: IEEE
 
» Buffer-Aided Relay Selection for Cooperative Relay Networks With Certain Information Rates and Delay Bounds
Abstract:
In this paper, we propose a relay selection scheme for cooperative buffer-aided relay networks with specific information rates and delay bounds. The proposed scheme differs from most of the well-known schemes in the literature that assume the source is saturated with data and/or without delay constraints. The proposed scheme is designed to encompass the delay-sensitive applications that are subject to delay limits and have certain rates. The proposed scheme exploits the channel state information, buffer state information, and delay state information to minimize the outage probability and achieve higher throughput. To achieve that, it uses these information to compromise between the selections of relays for reception and transmission. The proposed scheme is analyzed in the independent and identically distributed and independent and nonidentically distributed Rayleigh fading channels. The analysis is in terms of outage probability, packet dropping probability of the source node, packet dropping probability of the entire system, and throughput. For systems with high delay constraints, simulation results show that the proposed scheme offers lower packet dropping probability and higher throughput as compared to the renowned relay selection schemes.
Autors: Ali Ahmed Mohamed Siddig;Mohd Fadzli Mohd Salleh;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10499 - 10514
Publisher: IEEE
 
» Buffer-Layer Dependence of Interface Magnetic Anisotropy in Co2Fe0.4Mn0.6Si Heusler Alloy Ultrathin Films
Abstract:
Buffer-layer dependences of dead-layer thickness, saturation magnetization (, and interface magnetic anisotropy ( were systematically investigated for Co2Fe0.4Mn0.6Si (CFMS) Heusler alloy ultrathin films with Pd, Ru, and Cr buffer layers. Perpendicular magnetization was only achieved in 0.6 and 0.8 nm-thick CFMS ultrathin films deposited on Pd buffer layer and annealed at 400 °C. At the optimum annealing temperature of 400 °C, of 1.2 erg/cm2 was obtained for the Pd buffer layer, which was 3–6 times larger than those for Ru and Cr buffer layers. The difference in probably originates from the interdiffusion and different crystallized compounds at the interface between Pd (Ru, Cr) and CFMS layers.
Autors: Mingling Sun;Takahide Kubota;Yoshiaki Kawato;Shigeki Takahashi;Arata Tsukamoto;Yoshiaki Sonobe;Koki Takanashi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Building a New World (On Top of Our Legs) [Editorial]
Abstract:
Autors: Cristian Quintero;
Appeared in: IEEE Potentials
Publication date: Nov 2017, volume: 36, issue:6, pages: 3 - 3
Publisher: IEEE
 
» Building NVRAM-Aware Swapping Through Code Migration in Mobile Devices
Abstract:
Mobile applications are becoming increasingly feature-rich and powerful, but also dependent on large main memories, which consume a large portion of system energy, especially for devices equipped with 4/6 GB DRAM. Swapping inactive DRAM pages to byte-addressable, non-volatile memory (NVRAM) is a promising solution to this problem. However, most NVRAMs have limited write endurance and the current victim pages selecting algorithm does not aware it. Therefore, to make it practical, the design of an NVRAM based swapping system must also consider endurance. In this paper, we target at prolonging the lifetime of NVRAM based swap area in mobile devices by reducing the write activities to NVRAM based swap area. Different from traditional wisdom, such as wear leveling and hot/cold data identification, we propose to build a system called nCode, which exploits the fact that code pages are easy to identify, read-only, and therefore a perfect candidate for swapping. Utilizing NVRAM’s byte-addressability, we support execute-in-place (XIP) of the code pages in the swap area, without copying them back to DRAM based main memory. Experimental results based on the Google Nexus 5 smartphone show that nCode can effectively prolong the lifetime of NVRAM under various workloads.
Autors: Kan Zhong;Duo Liu;Lingbo Long;Jinting Ren;Yang Li;Edwin Hsing-Mean Sha;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3089 - 3099
Publisher: IEEE
 
» Built-in-Self-Calibration for I/Q Imbalance in Wideband Millimeter-Wave Gigabit Transmitters
Abstract:
This paper addresses the estimation and compensation of I/Q imbalance, one of the most prominent impairments found in wideband zero-intermediate frequency transceivers (TRxs). The I/Q imbalance encountered in this kind of TRx comprises not only frequency-selective gain and phase imbalance but also delay imbalance. Unless appropriate compensation is applied, the I/Q imbalance significantly degrades the performance of a communication system. This paper presents a novel compensation technique for transmitter I/Q imbalance based on built-in-self-calibration, a low cost and robust compensation technique that enables manufacturing as well as in-field calibration with low computational complexity. The method’s performance is evaluated in a TRx with 64-quadratic-amplitude modulation and 2 GHz of bandwidth implemented with real hardware. The measurements show that the proposed technique achieves an image rejection ratio greater than 35 dB in the entire 2 GHz bandwidth and an error vector magnitude lower than 3%.
Autors: Ainhoa Rezola;Juan F. Sevillano;Iñaki Gurutzeaga;David del Rio;Roc Berenguer;Igone Vélez;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4758 - 4769
Publisher: IEEE
 
» Cache Placement in Fog-RANs: From Centralized to Distributed Algorithms
Abstract:
To deal with the rapid growth of high-speed and/or ultra-low latency data traffic for massive mobile users, fog radio access networks (Fog-RANs) have emerged as a promising architecture for next-generation wireless networks. In Fog-RANs, the edge nodes and user terminals possess storage, computation and communication functionalities to various degrees, which provide high flexibility for network operation, i.e., from fully centralized to fully distributed operation. In this paper, we study the cache placement problem in Fog-RANs, by taking into account flexible physical-layer transmission schemes and diverse content preferences of different users. We develop both centralized and distributed transmission aware cache placement strategies to minimize users’ average download delay subject to the storage capacity constraints. In the centralized mode, the cache placement problem is transformed into a matroid constrained submodular maximization problem, and an approximation algorithm is proposed to find a solution within a constant factor to the optimum. In the distributed mode, a belief propagation-based distributed algorithm is proposed to provide a suboptimal solution, with iterative updates at each BS based on locally collected information. Simulation results show that by exploiting caching and cooperation gains, the proposed transmission aware caching algorithms can greatly reduce the users’ average download delay.
Autors: Juan Liu;Bo Bai;Jun Zhang;Khaled B. Letaief;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7039 - 7051
Publisher: IEEE
 
» Calculating All Minimal Transition-Based Sensor Activation Policies for the Purpose of Supervisory Control
Abstract:
Consider the problem of designing a supervisory control in which the supervisor has control not merely over the inputs (or actuators), but can also choose to turn sensors on or off. In this context, the supervisor can flexibly adjust the set of activated sensors to reduce sensor utilization without compromising the correctness of control decisions. Building upon existing methods for computing a transition-based minimal sensor activation policy, algorithms are presented in this technical note for computing all minimal transition-based sensor activation policies. This result is then extended for minimizing the numerical sensor activation cost for systems modeled by stochastic automata.
Autors: Weilin Wang;Chaohui Gong;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5894 - 5901
Publisher: IEEE
 
» Calculation of Critical Oscillation Modes for Large Delayed Cyber-Physical Power System Using Pseudo-Spectral Discretization of Solution Operator
Abstract:
In eigenanalysis of large delayed cyber-physical power system (DCPPS), power engineers are interested in critical electromechanical oscillation modes with damping ratios less than a specified threshold. To efficiently compute these modes, a method based on pseudo-spectral discretization of the solution operator of DCPPS (SOD-PS) is presented in this paper. First, the unique spectral mapping properties of solution operator are analyzed. The largest eigenvalues in moduli of the operator correspond to the ones of DCPPS with the largest real parts. Second, a rotation-and-multiplication preconditioning technique is presented to enhance the dispersion among eigenvalues of the solution operator's discretized matrix. Third, critical electromechanical oscillation modes of DCPPS with the least damping ratios are captured with priority and an accelerated convergence rate by the implicitly restarted Arnoldi algorithm. Subsequently, the small signal stability of DCPPS can be readily and reliably determined. In SOD-PS, the unique property of Kronecker product and the inherent sparsity in augmented system matrices are fully exploited to guarantee efficiency and scalability. The accuracy and efficiency of the presented method are intensively studied and thoroughly validated on the 16-generator 68-bus test system and a real-life large transmission grid.
Autors: Hua Ye;Qianying Mou;Yutian Liu;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4464 - 4476
Publisher: IEEE
 
» Capacity of Social-Aware Wireless Networks With Directional Antennas
Abstract:
The widespread of smart phones has brought new social-aware features to wireless networks. Users prefer to forward traffic to their social contacts in social-aware networks, which is highly different from the traditional uniform traffic pattern. To this end, we analyze a social-aware wireless network, which is modeled by the social contacts between nodes, and explore its impact on network throughput capacity. We present that it can refine social contacts, thus improving the network capacity. Moreover, directional antennas are applied to further enhance the capacity performance, which can reduce the interference brought by other simultaneous communications. We derive the throughput capacity for social-aware networks with single-beam and multi-beam directional antenna, respectively. For single-beam directional antenna, we prove that when wireless networks are dominated by traffics of short-distance social contact, the throughput capacity can be promoted from order of to . In addition, when the beamwidth is at order of , the throughput capacity is a constant. Thus, the wireless network is scalable. For multi-beam antennas, we prove that when sidelobe gain is at order of , where is main lobe gain, compared with the single-beam case, the network capacity can achieve the order of .
Autors: Zhida Qin;Xiaoying Gan;Jingchao Wang;Luoyi Fu;Xinbing Wang;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4831 - 4844
Publisher: IEEE
 
» Carrier Frequency and DOA Estimation of Sub-Nyquist Sampling Multi-Band Sensor Signals
Abstract:
With the increase of signal bandwidth demands in these applications, it is a technical challenge to achieve the required high Nyquist sampling rate. In this paper, a new sub-Nyquist sampling array architecture for the multi-band signal carrier frequency and DOA estimation based on a uniform linear array is proposed, which consists of a two-stage estimate algorithm and the corresponding parameter pairing approach. We first adopt a sub-Nyquist sampling structure, namely, a modulated wideband converter (MWC), to sample the received signal at the reference sensor, and then the signal is reconstructed and the carrier frequencies are estimated accordingly. Second, the sub-Nyquist sampling data of other sensors are similarly obtained by using one channel of the MWC, respectively. In doing so, conventional DOA estimation algorithms can be adopted for the multi-band signals and a linearly correlated steering vector can be easily resolved. Furthermore, an effective pairing approach is also developed to match the multi-band signals in the estimated DOAs. The effectiveness of all the proposed methods is verified by simulation results.
Autors: Can Cui;Wen Wu;Wen-Qin Wang;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7470 - 7478
Publisher: IEEE
 
» Cascaded Channel Model, Analysis, and Hybrid Decoding for Spin-Torque Transfer Magnetic Random Access Memory
Abstract:
Spin-torque transfer magnetic random access memory (STT-MRAM) is a promising non-volatile memory technology widely considered to replace dynamic random access memory (DRAM). However, there still exist critical technical challenges to be tackled. For example, process variation and thermal fluctuation may lead to both write errors and read errors, severely affecting the reliability of the memory array. In this paper, we first propose a novel cascaded channel model for STT-MRAM that facilitates fast error rate simulations and more importantly the theoretical design and analysis of memory sensing and channel coding schemes. We analyze the raw bit error rate and probabilities of dominant error events, and derive the maximum likelihood decision criterion and the log-likelihood ratio of the cascaded channel. Based on these works, we further propose a two-stage hybrid decoding algorithm for extended Hamming codes for STT-MRAM. Simulation results demonstrate the effectiveness of the proposed hybrid decoding algorithm for improving the reliability of STT-MRAM in the presence of both write errors and read errors and supporting its potential applications, such as replacing DRAM.
Autors: Kui Cai;Kees A. Schouhamer Immink;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 11
Publisher: IEEE
 
» Catheter Hydrophone Aberration Correction for Transcranial Histotripsy Treatment of Intracerebral Hemorrhage: Proof-of-Concept
Abstract:
Histotripsy is a minimally invasive ultrasound therapy that has shown rapid liquefaction of blood clots through human skullcaps in an in vitro intracerebral hemorrhage model. However, the efficiency of these treatments can be compromised if the skull-induced aberrations are uncorrected. We have developed a catheter hydrophone which can perform aberration correction (AC) and drain the liquefied clot following histotripsy treatment. Histotripsy pulses were delivered through an excised human skullcap using a 256-element, 500-kHz hemisphere array transducer with a 15-cm focal distance. A custom hydrophone was fabricated using a mm PZT-5h crystal interfaced to a coaxial cable and integrated into a drainage catheter. An AC algorithm was developed to correct the aberrations introduced between histotripsy pulses from each array element. An increase in focal pressure of up to 60% was achieved at the geometric focus and 27%–62% across a range of electronic steering locations. The sagittal and axial −6-dB beam widths decreased from 4.6 to 2.2 mm in the sagittal direction and 8 to 4.4 mm in the axial direction, compared to 1.5 and 3 mm in the absence of aberration. After performing AC, lesions with diameters ranging from 0.24 to 1.35 mm were generated using electronic steering over a mm grid in a tissue-mimicking phantom. An average volume of 4.07 ± 0.91 mL was liquefied and drained after using electronic steering to treat a 4.2-mL spherical volume in in vitro bovine clots through the skullcap.
Autors: Tyler Gerhardson;Jonathan R. Sukovich;Aditya S. Pandey;Timothy L. Hall;Charles A. Cain;Zhen Xu;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Nov 2017, volume: 64, issue:11, pages: 1684 - 1697
Publisher: IEEE
 
» Centralized Optimization for Dec-POMDPs Under the Expected Average Reward Criterion
Abstract:
In this paper, the decentralized partially observable Markov decision process (Dec-POMDP) systems with discrete state and action spaces are studied from a gradient point of view. Dec-POMDPs have recently emerged as a promising approach to optimizing multiagent decision making in the partially observable stochastic environment. However, the decentralized nature of the Dec-POMDP framework results in a lack of shared belief state, which makes the decision maker impossible to estimate the system state based on local information. In contrast to the belief-based policy, this paper focuses on optimizing the decentralized observation-based policy, which is easily to be applied and does not have the sharing problem. By analyzing the gradient of the objective function, we have developed a centralized stochastic gradient policy iteration algorithm to find the optimal policy on the basis of gradient estimates from a single sample path. This algorithm does not need any specific assumption and can be applied to most practical Dec-POMDP problems. One numerical example is provided to demonstrate the effectiveness of the algorithm.
Autors: Xiaofeng Jiang;Xiaodong Wang;Hongsheng Xi;Falin Liu;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 6032 - 6038
Publisher: IEEE
 
» Ceramic Bearings for Electric Motors: Eliminating Damage with New Materials
Abstract:
Since the advent of variable frequency drive motors, standard rolling element bearings have been failing from electrical arcing because of stray electrical currents in the motors. This article will explore the damage mechanism in the bearings and introduce the use of ceramic rolling element bearings to eliminate this issue. Case histories will be provided.
Autors: James A. Oliver;Gustavo Guerrero;Josh Goldman;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 14 - 20
Publisher: IEEE
 
» Challenges and Open Problems in Signal Processing: Panel Discussion Summary from ICASSP 2017 [Panel and Forum]
Abstract:
This column summarizes the panel on open problems in signal processing, which took place on 5 March 2017 at the International Conference on Acoustics, Speech, and Signal Processing (ICASSP) in New Orleans, Louisiana. The goal of the panel was to draw attention to some of the challenges and open problems in various areas of signal processing and generate discussion on future research areas that can be of major significance and impact in signal processing. Five leading experts representing diverse areas within signal processing made up the panel.
Autors: Yonina C. Eldar;Alfred O. Hero III;Li Deng;Jeff Fessler;Jelena Kovacevic;H. Vincent Poor;Steve Young;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 8 - 23
Publisher: IEEE
 
» Chance-Constrained Economic Dispatch With Non-Gaussian Correlated Wind Power Uncertainty
Abstract:
Extending traditional deterministic economic dispatch to incorporate significant stochastic wind power is an important but challenging task in today's power system decision making. In this paper, this issue is formulated as a chance-constrained economic dispatch (CCED) problem. Usually, in the presence of non-Gaussian correlated random variables, both the objective function and constraints are difficult to handle. To address this issue, this paper provides a novel method dealing with non-Gaussian random variables. First, the Gaussian mixture model is adopted to represent the joint probability density function of power output for multiple wind farms. Then, analytical formulae are derived that can be used for fast computation of partial derivatives of the objective function and transformation of chance constraints into linear ones. Thereafter, the CCED can be solved as a deterministic linear convex optimization with a global optimal solution. The effectiveness and efficiency of the proposed methodology are validated via a case study with a modified IEEE 39-bus system.
Autors: Zhiwen Wang;Chen Shen;Feng Liu;Xiangyu Wu;Chen-Ching Liu;Feng Gao;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4880 - 4893
Publisher: IEEE
 
» Changes in the Editorial Board
Abstract:
After nine years (the maximum three consecutive terms) on the Editorial Board of the IEEE Transactions on Electron Devices (T-ED), Prof. David Esseni from the University of Udine, Prof. Jason Woo from the University of California at Los Angeles, and Prof. Ru Huang from Peking University have stepped down from their Editor positions in MOS Devices and Technology. I would like to express my sincere gratitude—and the gratitude of the Electron Device Society community at large—to David, Jason, and Ru for their commitment, dedication, and hard work during their term of service. Our very best wishes to them in their future endeavors.
Autors: Giovanni Ghione;Yogesh Singh Chauhan;Karol Kalna;Giovanni Verzellesi;Runsheng Wang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4372 - 4373
Publisher: IEEE
 
» Channel Condition Aware Detection in Statistical Signal Transmission
Abstract:
Heterogeneous network (HetNet) plays an important role in the upcoming 5G communications. A HetNet in futuristic communications is envisaged to provide full access data services, such that users will always have the best service with their available radio resources. To realize a full access HetNet, statistical signal transmission (SST) can be an important enabling technique. SST exploits statistical features of ordinary signals as a data transmission scheme to carry information data. Due to its inherent unique properties, SST signal is more robust than ordinary signals in conventional quasi-static channels. However, detection of SST signals in fast time-varying channels will face challenges. Motivated by this fact, this paper aims to analyze the impact of fast time-varying channels to SST, and reveals negative effects of burst of deep fading channel-state (BDFC) and feature dissipation with out-of-phase (FDOP). Accordingly, we design an automatic re-transmission scheme and a fragmental feature capturing method to mitigate the aforementioned issues, respectively. Based on these studies, we propose a channel condition aware detection scheme for SST, aiming to enhance SST detection performance in fast time-varying channels. Numerical results show that with the proposed scheme, a maximum gain of more than 10 dB can be obtained under either BDFC or FDOP condition. Furthermore, it is also demonstrated that the proposed scheme is robust with imperfect channel coherence time information, which is attractive for practical applications.
Autors: Tianheng Xu;Mengying Zhang;Sha Yao;Honglin Hu;Hsiao-Hwa Chen;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7221 - 7234
Publisher: IEEE
 
» Channel Estimation for FDD Multi-User Massive MIMO: A Variational Bayesian Inference-Based Approach
Abstract:
This paper addresses downlink channel estimation for frequency division duplex multi-user massive multiple-input multiple-output systems. Suppose that a base station communicates with mobile users, then the task is to estimate channel matrices, each corresponding to one user. Due to the limited scattering in physical propagation, each channel matrix is sparse in the virtual angular domain. Besides, different user links tend to share some common scatterers. As such, different channel matrices may have a partially common sparsity pattern. These observations motivate us to take a variational Bayesian inference based approach for channel estimation. Specifically, we design a Gaussian mixture prior model, which can efficiently capture the individual sparsity in each channel matrix and the partially joint sparsity shared by different channel matrices. Furthermore, we develop a variational expectation maximization strategy to estimate the hyperparameters associated with the prior model and the channel matrices. Compared with the existing counterparts, the proposed approach achieves much better performance in terms of the channel estimation accuracy, while maintaining a low computational complexity.
Autors: Xiantao Cheng;Jingjing Sun;Shaoqian Li;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7590 - 7602
Publisher: IEEE
 
» Channel Probing in Opportunistic Communication Systems
Abstract:
We consider a multi-channel communication system in which a transmitter has access to channels, but does not know the state of any of the channels. We model the channel state using an ON/OFF Markov process, and allow the transmitter to probe a single channel at predetermined probing intervals to decide over which channel to transmit. For models in which the transmitter must transmit over the probed channel, it has been shown that a myopic policy probing the channel most likely to be ON is optimal. In this paper, we allow the transmitter to select a channel over which to transmit that is potentially different from the probed channel. For a system of two channels, we show that the choice of which channel to probe does not affect the throughput. For a system with many channels, we show that a probing policy that probes the channel that is the second-most likely to be ON results in higher throughput. We extend the channel probing problem to dynamically choose when to probe based on probing history, and characterize the optimal probing policy for various scenarios.
Autors: Matthew Johnston;Isaac Keslassy;Eytan Modiano;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7535 - 7552
Publisher: IEEE
 
» Channel Training for MIMO Relay Systems in the Presence of Interference
Abstract:
In this paper, we propose an optimal channel training method in the sense of linear minimum mean square error for multiple-input multiple-output amplify-and-forward relay systems in the presence of interference. By using a relay processing matrix, the received interference is cancelled or mitigated. To make the problem tractable, we first derive the optimal structure of the training signal and the relay processing matrix. Then, we propose an optimal channel training method. In order to reduce the complexity, we also propose an asymptotically optimal channel training method. Simulation results demonstrate that the two proposed methods outperform the conventional training signal design methods in terms of both the mean square error and in the bit error rate.
Autors: Chang-Jae Chun;Il-Min Kim;Dong-Woo Lim;Hyung-Myung Kim;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10601 - 10605
Publisher: IEEE
 
» Channel-Aware Resource Allocation for Energy-Efficient Cloud Radio Access Networks Under Outage Specifications
Abstract:
This paper investigates a cloud radio access network (C-RAN) architecture for future wireless network, which focuses on centralized processing for spatially distributed remote radio heads (RRHs). Our main goal is to promote an energy efficient C-RAN under the consideration of multiple access interference (MAI) and imperfect channel state information at the transmitter (CSIT) via outage-aware resource allocation. The closed-form expression of fading-induced outage probability for each transceiver pair will be established by analyzing the statistical property of signal-to-interference-plus-noise. In the course of finding feasible solutions to enhance energy efficiency, the optimization procedures named C-RAN-based energy efficient power allocation (CEEPA) and low-complexity CEEPA are proposed. As the number of RRHs grows to infinity, the deterministic equivalents of performance metrics can be derived by applying recent results from random matrix theorem, which lead to an efficient way to obtain the asymptotic-optimal resource allocation policy. Also, the regularized zero-forcing precoding technique is adopted to mitigate MAI and can tackle the impact of imperfect CSIT thanks to the derivation of deterministic equivalents. Numerical simulations show that the proposed resource allocation schemes can provide better energy efficiency and the accuracy of asymptotic expressions is also verified. Furthermore, the merit of a distributed antenna system is demonstrated through the comparison with centralized antenna system.
Autors: Pei-Rong Li;Kai-Ten Feng;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7389 - 7403
Publisher: IEEE
 
» Characteristic Analysis of Surface Permanent-Magnet Vernier Motor According to Pole Ratio and Winding Pole Number
Abstract:
This paper aims to analyze the characteristics of a surface permanent-magnet Vernier motor (SPMVM) according to the pole ratio among the rotor magnet pole pairs, stator teeth, and winding pole number. The SPMVM has the same operational principle as a magnetic gear, and it is operated using the space harmonics of the air-gap flux density due to the magnetomotive force and air-gap permeance. In this paper, first, the design parameters of the SPMVM are specified based on an analytical calculation of the air-gap magnetic flux density. Moreover, various combinations of the rotor magnet pole pairs and stator teeth number are made and compared according to the operational principle of a Vernier motor using a 2-D finite-element method.
Autors: Shi Hyoseok;Noboru Niguchi;Katsuhiro Hirata;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Characterization of Permanent Magnet Magnetization
Abstract:
The performances of electrical machines highly depend on the behavior of materials, such as steel, copper, and permanent magnet. This paper focuses on permanent magnets whose magnetization must be precisely known. Thus a non-destructive approach which includes a combination of experiments and inverse problem, using the magnetostatic moment method, is presented in order to determine the magnetization of the magnet. With a Hall sensor, a scan of the field around the sample is made. These measurements and a numerical approach allow us to deduce the sample magnetization. Studies of two samples illustrate the advantages of this method.
Autors: Laure Arbenz;Olivier Chadebec;Christophe Espanet;Youness Rtimi;Gilles Cauffet;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Characterization of the Interfacial Dzyaloshinskii–Moriya Interaction in Pt/Co2FeAl0.5Si0.5 Ultrathin Films by Brillouin Light Scattering
Abstract:
Brillouin light scattering (BLS) combined with vibrating sample magnetometry (VSM) have been used to investigate the Dzyaloshinskii–Moriya interaction (DMI) in Pt-buffered Co2FeAl0.5Si0.5 ultrathin films of various thicknesses. VSM measurements of the Co2FeAl0.5Si0.5 (CFAS) thickness dependence of the saturation magnetic moment per unit area revealed a magnetization at saturation of 1286 emu/cm3 and 0.31 nm magnetic dead layer. Furthermore, thickest films ( nm) are in-plane magnetized, while the thinner ones are perpendicular magnetized. BLS measurements, in the Damon–Eshbach geometry, under an in-plane applied magnetic field revealed the non-reciprocity of the spin waves (SWs) propagating in opposite directions (Stokes and anti-Stokes lines) due to the Pt-induced DMI. Stokes and anti-Stokes lines’ frequency mismatch varies linearly as function of the SW vector allowing the determination of the effective DMI constant. Its thickness dependence leads to determine a value of −0.42 pJ/m for the DMI interface constant, which is significantly lower than that of Pt/Co/AlOx films. Moreover, BLS measurements revealed that the effective magnetization varies linearly with the reciprocal effective CFAS thickness due to the perpendicular interface anisotropy, estimated to be 0.49 mJ/m2, which reinforces the perpendicular magnetization easy axis.
Autors: M. Belmeguenai;M. S. Gabor;Y. Roussigné;S. M. Chérif;A. Stashkevich;T. Petrisor;R. B. Mos;C. Tiusan;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Characterization of UHF Band LC Filter With RF Spiral Inductor Using Carbonyl-Iron Powder/Epoxy Composite Magnetic and Chip Capacitor
Abstract:
In order to realize the -factor increase scheme for a radio frequency (RF) spiral inductor used in the RF front/end circuit of smart phone handset, an introduction of carbonyl-iron powder (CIP)/epoxy composite magnetic core to air-core spiral inductor has been done. The composite magnetic core made by metal-mask printing consisted of mean diameter CIP and epoxy resin matrix. A two-turn copper spiral inductor with composite magnetic core filled only in spacing between conductor lines was fabricated. The -factor of the inductor with composite magnetic core is about 1.3 times higher than that of an air-core spiral inductor at around 0.7 GHz. An important effect of -factor increase by embedded composite magnetic core in the spacing between conductor lines is obtained. A main reason is that a proximity effect is suppressed in conductor line of the spiral coil. In addition, the simplest LC filter simulating RF circuit with the RF spiral inductor using the composite and a chip capacitor was fabricated and evaluated. The transmission coefficient of the composite magnetic core spiral inductor was about 0.9 times lower than that of the same size air-core spiral inductor. The filter characteristic of the composite core inductor was superior to that of the air-core inductor.
Autors: Makoto Sonehara;Sota Yamaguchi;Yuki Miyajima;Toshiro Sato;Takeshi Inomata;Yuji Ono;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Characterizing a Preclinical Magnetic Particle Imaging System With Separate Pickup Coil
Abstract:
Magnetic particle imaging (MPI) is an emerging technology with the potential for great impact on both medicine and biomedical research. Its optimization and acceptance are dependent upon a significant research effort in the development of tracer materials, data acquisition equipment, and image reconstruction techniques. We present initial results obtained from a prototype signal acquisition instrument designed to offer improvements to the sensitivity, and signal-to-noise ratio (SNR), of a preclinical MPI system (Bruker 25/20). We present the Fourier analysis of the signals detected using both the original data collection instrument provided with the MPI system, and the new prototype detector. By comparison of the spectra obtained, we show that the imaging signals from the prototype instrument are of greater intensity, and extend into higher frequencies, than those obtained using the original measurement instrument. We present image reconstructions of vascular phantoms containing tracer at concentrations between c(Fe) = 0.1 and 0.0125 mol/L. The improved sensitivity of the prototype detector allows the resolution of phantoms at tracer concentrations below those attainable using the original detector instrument. Finally, we quantify the improvement offered by the new detector based on a summation of the SNR values above a background threshold, within the frequency region of interest for MPI data acquisition. By plotting these totals at a variety of sample concentrations, we calculate a final receive gain (FRG) factor to describe the improvement offered by the new detector. For the prototype studied, we find FRG = 4.7 ± 0.6.
Autors: James Wells;Hendrik Paysen;Olaf Kosch;Norbert Löwa;Florian Schmitzberger;Marcus Makowksi;Jochen Franke;Lutz Trahms;Frank Wiekhorst;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Characterizing Angular Dependence of Spin-Orbit Torque Effective Fields in Pt/(Co/Ni)2/Co/IrMn Structure
Abstract:
We investigate the interplay between the spin-orbit torque (SOT)-induced effective fields and the azimuth angle of the magnetization vector with respect to the applied current. A method to quantify the ratio of the planar Hall effect to the anomalous Hall effect in perpendicular magnetic anisotropy (PMA) structures by using the low field harmonic Hall voltage measurement technique is devised. The validity of the ratio is confirmed by measuring the PMA effective field. In addition, a technique to characterize the SOT effective fields as a function of the magnetization vector azimuth angle with respect to the current direction is proposed and experimentally validated. The experimental results are in quantitative agreement with our derivations. Our measurement reveals that the field-like effective SOT fields are minima when the azimuth angle of magnetization with respect to the current is at 45°.
Autors: Christian Engel;Sarjoosing Goolaup;Feilong Luo;Wen Siang Lew;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Chirped-Pulse Phase-Sensitive Reflectometer Assisted by First-Order Raman Amplification
Abstract:
The use of linearly chirped probe pulses in phase-sensitive optical time-domain reflectometry (ΦOTDR) technology has been recently demonstrated to allow for high-resolution, quantitative, and dynamic temperature or strain variation measurements in a simple and very robust manner. This new sensing technology, known as chirped-pulse ΦOTDR, had a maximum reported sensing range of 11 km. In this paper, a 75-km sensing range with 10-m spatial resolution is demonstrated by using bidirectional first-order Raman amplification. The system is capable of performing truly linear, single-shot measurements of strain perturbations with an update rate of 1-kHz and 1-nε resolution. The time-domain trace of the sensor exhibits a signal-to-noise ratio (SNR) in the worst point of >3 dB, allowing to monitor vibrations up to 500 Hz with remarkable accuracy. To demonstrate the capabilities of the proposed system, we apply <;100 nε vibrations in the noisiest point of the fiber, with a frequency modulated from 70 to 150 Hz over a period of 10 s. The results obtained in these conditions demonstrate a vibration detection SNR of >20 dB (with only 300-ms analysis window and no postprocessing) and no evidence of nonlinearity in the acoustic response. The optical nonlinear effects that the probe pulse could suffer along the sensing fiber are thoroughly studied, paying special attention to potential distortions of the pulse shape, particularly in its instantaneous frequency profile. Our analysis reveals that, for proper values of peak power, the pulse does not suffer any major.
Autors: Juan Pastor-Graells;Javier Nuño;María Rosario Fernández-Ruiz;Andres Garcia-Ruiz;Hugo F. Martins;Sonia Martin-Lopez;Miguel Gonzalez-Herraez;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4677 - 4683
Publisher: IEEE
 
» CI Thermometer: Visualizing Confidence Intervals in Correlation Analysis
Abstract:
Correlation analysis is one of the most popular statistical methods. Despite that, the way research reports correlation is often misleading. The difficulty increases with the amount of information that must be read and interpreted. The proposed CI thermometer makes correlation matrices much easier to read and provides information that would be difficult to interpret when presented in another way.
Autors: Agnieszka Wnuk;Konrad J. Dębski;Marcin Kozak;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 103 - 108
Publisher: IEEE
 
» CIS Publication Spotlight [Publication Spotlight]
Abstract:
Presents a listing of books recently published in the field of computational intelligence.
Autors: Haibo He;Jon Garibaldi;Kay Chen Tan;Graham Kendall;Yaochu Jin;Yew-Soon Ong;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 9 - 11
Publisher: IEEE
 
» CIS Publications in the Spotlight [President's Message]
Abstract:
Presents the President’s message for this issue of the publication.
Autors: Pablo A. Estevez;
Appeared in: IEEE Computational Intelligence Magazine
Publication date: Nov 2017, volume: 12, issue:4, pages: 4 - 13
Publisher: IEEE
 
» Clarifications on the Construction and Use of the ManyBugs Benchmark
Abstract:
High-quality research requires timely dissemination and the incorporation of feedback. Since the publication of the ManyBugs benchmark and its release on http://repairbenchmarks.cs.umass.edu/, researchers have provided feedback on the benchmark's construction and use. Here, we describe that feedback and our subsequent improvements to the ManyBugs benchmark.
Autors: Claire Le Goues;Yuriy Brun;Stephanie Forrest;Westley Weimer;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Nov 2017, volume: 43, issue:11, pages: 1089 - 1090
Publisher: IEEE
 
» Closed-Form Approximations for Coverage Probability of Multistream MIMO-ZFBF Receivers in HetNets
Abstract:
The evaluation of the coverage probability of multistream multiple-input multiple-output (MIMO) communications in HetNets subject to noise, fading, and intercell interference is undoubtedly intricate. Unfortunately, the current literature misses its comprehensive evaluation, as the effects of noise and cross-stream correlation are often overlooked. Furthermore, computationally friendly expressions of the coverage probability allowing engineering insights and adaptive system design are lacking. For multistream MIMO zero-forcing beamforming, in this paper we tackle these issues by considering scenarios where a receiver is in the coverage if all of its data-streams are successfully decoded. Assuming the max signal-to-interference-plus-noise ratio (SINR) cell association (CA), we adopt the stochastic geometry tools to provide an upper bound and an easy-to-compute closed-form lower bound on the coverage probability, while their accuracies are confirmed against extensive simulations. Our contributions are as follows. We prove that full correlation of data streams of a given link slightly reduces the coverage performance. We show that from a coverage probability perspective, the single stream communication is preferable. We exploit our analysis to explore several pertinent design issues, which have not fully discussed in the literature. Our results demonstrate tradeoffs between densification and multiplexing gains. We, further, see that by appropriately designating feedback channel with modest capacity 8 bits per frame per user, the spatial throughput grows by nearly 180 over the conventional 1-bit feedback scenario. Finally, We present important extensions of our analysis to underlay spectrum sharing, practical aspects of the max-SINR CA, and a nonhomogeneous path loss environment.
Autors: Mohammad G. Khoshkholgh;Victor C. M. Leung;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9862 - 9879
Publisher: IEEE
 
» Closed-Form Expressions for ICI/ISI in Filtered OFDM Systems for Asynchronous 5G Uplink
Abstract:
One of the major purposes for fifth generation (5G) communications waveform design is to relax the synchronization requirements for supporting efficient massive machine type communications (MTCs). Polynomial cancellation coded orthogonal frequency-division multiplexing (PCC-OFDM) and universal filtered multi-carrier (UFMC) are designed to reduce the sidelobes of the OFDM waveform to protect against intercarrier interference (ICI) in the 5G uplink. To the best of our knowledge, there is no analysis of the effect of ICI for the UFMC system with time offset transmissions that many arise in MTC scenarios. Furthermore, there is no study on reducing the computational complexity of the UFMC system. This paper provides closed-form expressions for time offsets interference in such a case for OFDM, PCC-OFDM, and UFMC. This paper also presents theoretical analysis for the signal-to-interference-plus-noise ratio, achievable rate, and bit error ratio performance. The results show that PCC-OFDM significantly protects against ICI at the cost of halving the spectral efficiency. UFMC improves the ICI and intersymbol interference protection performance, especially when the length of time offset is very small, at the cost of significantly increasing the computational complexity. Finally, this paper proposes the overlap and adds UFMC and a variant of UFMC using infinite impulse response prototype filter banks to reduce the processing complexity.
Autors: Shendi Wang;John S. Thompson;Peter M. Grant;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4886 - 4898
Publisher: IEEE
 
» Cloth Animation Retrieval Using a Motion-Shape Signature
Abstract:
In cloth simulation, the behavior of textiles largely depends on initial conditions, parameters, and simulation techniques. Usually, several combinations of those aspects are altered until a simulation setting is found to create a satisfying animation. However, if an initial condition, such as a collision object, is changed afterward or the cloth behavior is transferred to a different scene, the existing set of simulation parameters could no longer be suitable for the desired look. In this case, it is difficult to find a new configuration by changing parameters manually and to determine if it conforms the desired properties. This article introduces a feature vector that is used as a motion-shape signature to capture the spatiotemporal shape characteristics of cloth and can be applied as a similarity measure for physics-based cloth animations.
Autors: Markus Huber;Bernhard Eberhardt;Daniel Weiskopf;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 52 - 64
Publisher: IEEE
 
» Cloud-Based Control Strategy: Downstream Defect Reduction in the Production of Electric Motors
Abstract:
Classical computing is shifted gradually into the cloud offering completely new possibilities in information usage, computing power, and application of learning algorithms. In this paper, a cloud-based architecture of control systems is investigated showing the benefit for multistage production systems. All sequential manufacturing and assembly processes are connected via a cloud-based architecture, which allows using information from a previous production step in one of the subsequent steps for downstream deviation compensation. This strategy is applied to the rotor production of electric motors in the automotive industry, as the current production shows high defect rates due to the lack of adequate sensor signals and optimization algorithms. The magnetization process of permanent magnets is executed in saturation so that the generation of deviations cannot be avoided by process control or process optimization. Instead, the variance in the magnetization signal must be compensated in a downstream process, here the rotor assembly stage. Project results show how such a cloud-based architecture can increase the product quality while decreasing the amount of scrap parts in a real industrial scenario, consequently saving valuable resources such as energy and raw materials. Reduction of deviations is crucial for this emerging industrial sector as electric motor production for vehicles is moving towards mass production in the future.
Autors: Daniel Coupek;Armin Lechler;Alexander Verl;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5348 - 5353
Publisher: IEEE
 
» Clustering Effect on the Frequency-Dependent Magnetic Properties of Fe–Co Micro Hollow Fiber Composites
Abstract:
Composite sheets including Fe–Co magnetic hollow fibers are applicable to near-field electromagnetic wave absorption sheets operating in excess of 1 GHz. To understand the frequency-dependent permeability behavior of composite sheets, the Landau–Lifshitz–Gilbert equation and effective medium theory which are including the effects of the eddy current losses of isolated fibers and magnetostatic correction in high volume fractions can be used. However, the simulation considering only these factors requires a very high damping factor to explain the measured results. Thus, the simulation also needs the consideration of the clustering effect of particles causing the additional eddy current losses. In this paper, a new simulation method for magnetic sheets with clustered particles is proposed to improve an understanding of changes in the high-frequency properties of magnetic composite sheets due to the clustering effect.
Autors: Moosung Choi;Sounghun Lee;Jongryoul Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Clutter Suppression via Hankel Rank Reduction for DFrFT-Based Vibrometry Applied to SAR
Abstract:
Hankel rank reduction (HRR) is a method that, by prearranging the data in a Hankel matrix and performing rank reduction via singular value decomposition, suppresses the noise of a time-history vector comprised of the superposition of a finite number of sinusoids. In this letter, the HRR method is studied for performing clutter suppression in synthetic aperture radar (SAR)-based vibrometry. Specifically, three different applications of the HRR method are presented. First, resembling the SAR slow-time signal model, the HRR method is utilized for separating a chirp signal immersed in a sinusoidal clutter. Second, using simulated airborne SAR data with 10 dB of signal-to-clutter ratio, the HRR method is applied to perform target isolation and to improve the results of an SAR-based vibration estimation algorithm. Finally, the vibrometry approach combined with the HRR method is validated using actual airborne SAR data.
Autors: Francisco Pérez;Balu Santhanam;Ralf Dunkel;Majeed M. Hayat;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2052 - 2056
Publisher: IEEE
 
» CMOS Scaling Trends and Beyond
Abstract:
Scaling transistors and following Moore’s law have served the industry well for more than 50 years in providing integrated circuits that are denser, cheaper, higher performance, and lower power. And despite occasional reports of its demise, Moore’s law is alive and well. But progress in scaling CMOS has not come easily. We’ve had to continually invent and introduce new materials and new device structures to deliver the performance, power, and cost improvements expected of each new technology generation. This article describes trends in CMOS scaling over the past decade and discusses some of the new device options and technology directions being explored to continue scaling into the future.
Autors: Mark T. Bohr;Ian A. Young;
Appeared in: IEEE Micro
Publication date: Nov 2017, volume: 37, issue:6, pages: 20 - 29
Publisher: IEEE
 
» CMOS-Compatible Contacts to n-InP
Abstract:
In the context of the development of silicon photonics, various Ti- and Ni-based alloyed metallizations have been investigated for the purpose of forming low resistivity and Si CMOS-compatible contacts to n-InP. The innovative Ni2P metallization combined with an in situ Ar+ preclean represents the most suitable available solution for the formation of ohmic contacts with a specific contact resistivity as low as on such a semiconductor. The latter additionally presents the advantage of being stable at least up to 350 °C and could therefore withstand additional integration processes conducted at this temperature.
Autors: Elodie Ghegin;Philippe Rodriguez;Mattia Pasquali;Isabelle Sagnes;János L. Lábár;Vincent Delaye;Tiphaine Card;Jérémy Da Fonseca;Christophe Jany;Fabrice Nemouchi;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4408 - 4414
Publisher: IEEE
 
» Co-Optimization of Energy and Ancillary Services for Hydrothermal Operation Planning Under a General Security Criterion
Abstract:
One of the most used methods for long-term hydrothermal operation planning is the stochastic dual dynamic programming (SDDP). Using this method, the immediate and future water opportunity cost can be balanced and an economic-dispatch policy can be defined for multiple reservoirs under inflow uncertainty. In this framework, equipment outages and reserve deliverability are generally disregarded, despite their strong impact on the operative plan. However, recent advances in robust optimization have shown how to endogenously account for security criteria in scheduling models with reduced computational burden. Within this framework, reserve deliverability is ensured across the network via the co-optimization of energy and reserves (ancillary services). In this paper, we propose a new multistage model for planning hydrothermal coordination that co-optimizes the nominal energy dispatch and individual up and down reserve allocations. The main goal of this paper is to address a general security criterion, such that, for each inflow scenario, the system is capable of withstanding the loss of up to components, i.e., generation or transmission assets. The proposed methodology uses the column-and-constraint generation algorithm to efficiently incorporate a compound umbrella set of contingencies in the SDDP algorithm. Results for the Brazilian power system data corroborate the effectiveness of the proposed model.
Autors: Alexandre Street;Arthur Brigatto;Davi M. Valladão;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4914 - 4923
Publisher: IEEE
 
» Codebook Design for Beam Alignment in Millimeter Wave Communication Systems
Abstract:
Owing to abundant spectrum resources, millimeter wave (mmwave) communication promises to provide Gbps data rates, which, however, may be restricted by large path-loss. Thus, antenna arrays are commonly used along with beam alignment (BA) as an important step to achieve the array gain. Efficient BA relies on the beam training codebook design. In this paper, we propose a new hierarchical codebook to achieve uniform BA performance with low overhead. To better elaborate on the design principle, a single-path channel model is considered first to frame the proposal. The codebook design is formulated as an optimization problem, where the ripple in the main/side lobes is constrained such that each training beam is close to the ideal one with a flat magnitude response and a narrow transition band. Then, we propose an efficient algorithm to find such a beam training codebook. Furthermore, we derive closed-form expressions of the BA misalignment probability or error rate of the proposed beam training codebook. Our results reveal that using the proposed codebook, the error rate of tree-search-based BA exponentially decreases with the SNR for a given channel, and linearly decreases in the log–log coordinate axis for a fading channel. We further propose a power allocation scheme used in different training stages to further improve the BA performance. Finally, the proposed framework is extended to the more complex case of multi-path channels. Numerical results confirm the effectiveness of the proposed training codebook and power allocation scheme as well as the accuracy of the performance analysis.
Autors: Jianjun Zhang;Yongming Huang;Qingjiang Shi;Jiaheng Wang;Luxi Yang;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4980 - 4995
Publisher: IEEE
 
» Coded Slotted ALOHA for Erasure Channels: Design and Throughput Analysis
Abstract:
In this paper, we investigate the design and analysis of coded slotted ALOHA (CSA) schemes in the presence of channel erasure. We design the code probability distributions for CSA schemes with repetition codes and maximum distance separable codes to maximize the expected traffic load, under both packet erasure channels and slot erasure channels. We derive the extrinsic information transfer (EXIT) functions of CSA schemes over erasure channels. By optimizing the convergence behavior of the derived EXIT functions, the code probability distributions to achieve the maximum expected traffic load are obtained. Then, we derive the asymptotic throughput of CSA schemes over erasure channels. In addition, we validate that the asymptotic throughput can give a good approximation to the throughput of CSA schemes over erasure channels.
Autors: Zhuo Sun;Yixuan Xie;Jinhong Yuan;Tao Yang;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4817 - 4830
Publisher: IEEE
 
» Coexistence of Wi-Fi and LAA Networks With Adaptive Energy Detection
Abstract:
Licensed-assisted access (LAA) of the long term evolution (LTE) has been standardized by the Third Generation Partnership Project (3GPP) in Release 13 to address the urgent issues of ever-increasing traffic demands in cellular systems. However, challenges arise for the efficient coexistence of Wi-Fi and LAA in the same unlicensed spectrum. In this paper, the impact of LAA's energy detection thresholds on such coexistence are investigated from the perspective of collisions occurring during downlink transmissions. To facilitate the efficient coexistence of Wi-Fi and LAA, a distributed algorithm is proposed to adaptively change the energy detection thresholds of LAA per user or per base station, so that the system encourages more concurrent transmissions without introducing too many collisions. Simulation results validate the effectiveness of the proposed adaptive algorithm.
Autors: Li Li;James P. Seymour;Leonard J. Cimini;Chien-Chung Shen;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10384 - 10393
Publisher: IEEE
 
» Cogging Torque and Unbalanced Magnetic Force Prediction in PM Machines With Axial-Varying Eccentricity by Superposition Method
Abstract:
This paper proposes a double superposition method to quickly and accurately predict the cogging torque and unbalanced magnetic force (UMF) of permanent magnet machines with axial-varying rotor eccentricities. The original axial-varying eccentric machine is cut into several uniform slices along the axial direction and each slice is considered to be axially uniform, i.e., axial even. For each axial-even eccentric machine slice, the circumferential superposition method can be used to predict the cogging torque and UMF of this slice. Finally, the cogging torque and UMF of the original axial-varying eccentric machine can be obtained by using an axial superposition technique which combines the cogging torque and UMF of each slice with different eccentricity magnitudes together. The 3-D finite-element analysis is adopted to validate the efficacy of the proposed method and the merit of high accuracy and computational efficiency is also identified by comparing the results predicted from these two methods.
Autors: Y. X. Li;Z. Q. Zhu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Cogging Torque Reduction by Elementary-Cogging-Unit Shift for Permanent Magnet Machines
Abstract:
This paper describes a method to reduce cogging torque in permanent magnet (PM) machines by shifting elementary-cogging unit (ECU). The ECU division principle and the feature of cogging torque produced by ECU are also discussed. The proper shift angles for each ECU are deduced according to both fractional and integral slot number per pole, by which any order harmonic cogging torque could be eliminated without the introduction of any new harmonic torque. This paper investigates the validity of the effectiveness of ECU shifting techniques using PM machines with different match of slot number per pole in 2-D finite-element models.
Autors: Jian Gao;Guang Wang;Xiao Liu;Wenjuan Zhang;Shoudao Huang;Huimin Li;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Cognitive Radio Network and Network Service Chaining toward 5G: Challenges and Requirements
Abstract:
Cognitive radio is a promising technology that answers the spectrum scarcity problem arising from the growth of usage of wireless networks and mobile services. Cognitive radio network edge computing will enhance the CRN capabilities and, along with some adjustments in its operation, will be a key technology for 5G heterogeneous network deployment. This article presents current requirements and challenges in CRN, and a review of the limited research work on the CRN cloud, which will take off CRN capabilities and 5G network requirements and challenges. The article proposes a cognitive radio edge computing access server deployment for network service chaining at the access layer level.
Autors: Ioanna Kakalou;Kostas E. Psannis;Piotr Krawiec;Radu Badea;
Appeared in: IEEE Communications Magazine
Publication date: Nov 2017, volume: 55, issue:11, pages: 145 - 151
Publisher: IEEE
 
» Colossal Positive Magnetoresistance in Oxygen-Deficient Ca4Mn3O10
Abstract:
Huge changes in resistance induced by an external magnetic field, i.e., a colossal magnetoresistance effect, is a long-lived theme of the research due to both fundamental science and device applications. Careful analysis of oxygen-deficient Ca4Mn3O10, synthesized by the citric acid method, establishes a direct correlation between magnetic and electric properties. An electric resistive anomaly at the magnetic ordering temperature of ~115 K supports this correlation. We currently report on a colossal positive magnetoresistance up to ~1300% below the metal-to-insulator transition temperature for oxygen-deficient Ca4Mn3O10. The positive magnetoresistance effect in this system may be attributed to the field-induced carrier localization.
Autors: Manimuthu Periyasamy;Anja Olafsen Sjåstad;Helmer Fjellvåg;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Combining Teaching and Research through Barcode Experiments
Abstract:
A core mission of university education is to train students' problem solving abilities, or in some cases, students' research skills. To achieve this, educators assign students certain experiment courses, where students complete a task following preset procedures. However, such courses often employ outdated teaching materials that are far from cutting-edge problems. Meanwhile, a preset experiment procedure cannot evoke students' innovations. In this article we introduce an experimental course we opened at Shanghai Jiao Tong University for junior-year students -- the Research-Oriented Course (ROC). ROC is based on a cutting-edge research project and includes an Introduction -- Demonstration -- Research -- Evaluation four-phase course as well as the T -- W -- R three-dimensional evaluation criteria. Evaluations showed that students finished their research tasks satisfactorily and they improved their research skills through this process.
Autors: Xinbing Wang;Jiaqi Liu;Zhe Yang;Junfa Mao;Luoyi Fu;Xiaoying Gan;Xiaohua Tian;
Appeared in: IEEE Communications Magazine
Publication date: Nov 2017, volume: 55, issue:11, pages: 159 - 165
Publisher: IEEE
 
» Comments on “A Cross-Layer Approach to Privacy-Preserving Authentication in WAVE-Enabled VANETs” by Biswas and Mišić
Abstract:
A WAVE-based cross-layer anonymous authentication scheme based on a variant of ECDSA (Biswas and Mišić “A Cross-layer approach to privacy-preserving authentication in WAVE-enabled VANETs,” IEEE Trans. Veh. Technol., vol. 62, no. 5, pp. 2182–2192, Jun. 2013.) was published for authenticity of vehicular safety application messages. Our result shows that, contrary to what is claimed, the scheme is entirely broken due to the insecurity of their underlying signature scheme: Their modification of ECDSA is insecure against secret key recovery attacks where anyone can recover OBUs’ or mobile nodes’ private keys from transmitted signed messages just eavesdropping.
Autors: Kyung-Ah Shim;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10588 - 10589
Publisher: IEEE
 
» Comments on “A General and Transformable Model Platform for Emerging Multi-Gate MOSFETs”
Abstract:
Hong et al. [1] presented an analytical solution for the electrostatic potential in undoped cylindrical MOSFETs, which was then employed within a well-known Pao-Sah integral to yield the device current. This same analytical solution and drain current calculation were presented in 2016 [2], but such work was not referenced by Hong et al. [1].
Autors: Giovanni M. Paolucci;Alessandro S. Spinelli;Christian Monzio Compagnoni;Paolo Tessariol;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1618 - 1618
Publisher: IEEE
 
» Comments on “Microstrip T-Junction Power Divider With Exponentially Tapered Transmission Lines”
Abstract:
In the above paper, Smith and Sigmarsson [1] proposed a T-junction unequal power divider using exponentially tapered transmission line (ENTL) and uniform transmission line (UTL). However, the cutoff wavelength defined in [1] and also in [2], from which the definition of has been adopted, are incorrect. So the entire analysis and design equations of [1] are questionable. Also, the authors have not shown the amplitude and phase imbalance variation over the frequency.
Autors: Rakesh Sinha;Ranadhir Chatterjee;Hungsun Son;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 1037 - 1038
Publisher: IEEE
 
» Comments on ScottKnottESD in Response to “An Empirical Comparison of Model Validation Techniques for Defect Prediction Models”
Abstract:
In this article, we discuss the ScottKnottESD test, which was proposed in a recent paper “An Empirical Comparison of Model Validation Techniques for Defect Prediction Models” that was published in this journal. We discuss the implications and the empirical impact of the proposed normality correction of ScottKnottESD and come to the conclusion that this correction does not necessarily lead to the fulfillment of the assumptions of the original Scott-Knott test and may cause problems with the statistical analysis.
Autors: Steffen Herbold;
Appeared in: IEEE Transactions on Software Engineering
Publication date: Nov 2017, volume: 43, issue:11, pages: 1091 - 1094
Publisher: IEEE
 
» Comments on the Proof of Adaptive Stochastic Set Cover Based on Adaptive Submodularity and Its Implications for the Group Identification Problem in “Group-Based Active Query Selection for Rapid Diagnosis in Time-Critical Situations”
Abstract:
We point out an issue with one of the results in Bellala et al. [1] that invokes a main result on adaptive stochastic minimum cost cover problem (Theorem 5.8) of Golovin and Krause. We construct an example that shows that the proof of Theorem 5.8 of Golovin and Krause is invalid, and therefore, the proof in Bellala et al. about the near-optimum performance of their algorithm is also invalid.
Autors: Feng Nan;Venkatesh Saligrama;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7612 - 7614
Publisher: IEEE
 
» Common Learning Objectives for Undergraduate Control Systems Laboratories
Abstract:
Course objectives, like research objectives and product requirements, help provide clarity and direction for faculty and students. Unfortunately, course and laboratory objectives are not always clearly stated. Without a clear set of objectives, it can be hard to design a learning experience and determine whether students are achieving the intended outcomes of the course or laboratory. In this paper, a common set of laboratory objectives, concepts, and components of a laboratory apparatus for undergraduate control systems laboratories were identified. A panel of 40 control systems faculty members completed a multi-round Delphi survey to bring them toward consensus on the common aspects of their laboratories. These panelists identified 15 laboratory objectives, 26 concepts, and 15 components common to their laboratories. Then an 45 additional faculty members and practitioners completed a follow-up survey to gather feedback on the results. In both surveys, each participant rated the importance of each item. While average ratings differed slightly between the two groups, the order in which the items were ranked was similar. Important examples of common learning objectives include connecting theory to what is implemented in the laboratory, designing controllers, and modeling systems. The most common component in both groups was MathWorks software. Some of the common concepts include block diagrams, stability, and PID control. Defining common aspects of undergraduate control systems laboratories enables common development, detailed comparisons, and simplified adaptation of equipment and experiments between campuses and programs.
Autors: Rebecca M. Reck;
Appeared in: IEEE Transactions on Education
Publication date: Nov 2017, volume: 60, issue:4, pages: 257 - 264
Publisher: IEEE
 
» Communication in the Presence of a State-Aware Adversary
Abstract:
We study communication systems over the state-dependent channels in the presence of a malicious state-aware jamming adversary. The channel has a memoryless state with an underlying distribution. The adversary introduces a jamming signal into the channel. The message and the entire state sequence are known non-causally to both the encoder and the adversary. This state-aware adversary may choose an arbitrary jamming vector depending on the message and the state vector. Taking an arbitrarily varying channel (AVC) approach, we consider two setups, namely, the discrete memoryless Gel’fand–Pinsker AVC and the additive white Gaussian dirty paper (DP) AVC. We determine the randomized coding capacity of both the AVCs under a maximum probability of error criterion. Similar to other randomized coding setups, we show that the capacity is the same even under the average probability of error criterion. Though the adversary can choose an arbitrary vector jamming strategy, we prove that the adversary cannot affect the rate any worse than when it employs a memoryless strategy, which depends only on the instantaneous state. Thus, the AVC capacity characterization is given in terms of the capacity of the worst memoryless channels with state, induced by the adversary employing such memoryless jamming strategies. For the DP-AVC, it is further shown that among memoryless jamming strategies, none impact the communication more than a memoryless Gaussian jamming strategy which completely disregards the knowledge of the state. Thus, the capacity of the DP-AVC equals that of a standard additive white Gaussian noise (AWGN) channel with two independent sources of AWGN, i.e., the channel noise and the jamming noise.
Autors: Amitalok J. Budkuley;Bikash Kumar Dey;Vinod M. Prabhakaran;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7396 - 7419
Publisher: IEEE
 
» Communications Education & Training: Scholarship of Research and Supervision in Communications
Abstract:
Autors: Dave Michelson;Peter Ostafich;Carolyn Ottman;
Appeared in: IEEE Communications Magazine
Publication date: Nov 2017, volume: 55, issue:11, pages: 158 - 158
Publisher: IEEE
 
» Compact Hash Codes for Efficient Visual Descriptors Retrieval in Large Scale Databases
Abstract:
In this paper, we present an efficient method for visual descriptors retrieval based on compact hash codes computed using a multiple k-means assignment. The method has been applied to the problem of approximate nearest neighbor (ANN) search of local and global visual content descriptors, and it has been tested on different datasets: three large scale standard datasets of engineered features of up to one billion descriptors (BIGANN) and, supported by recent progress in convolutional neural networks (CNNs), on CIFAR-10, MNIST, INRIA Holidays, Oxford 5K, and Paris 6K datasets; also, the recent DEEP1B dataset, composed by one billion CNN-based features, has been used. Experimental results show that, despite its simplicity, the proposed method obtains a very high performance that makes it superior to more complex state-of-the-art methods.
Autors: Simone Ercoli;Marco Bertini;Alberto Del Bimbo;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2521 - 2532
Publisher: IEEE
 

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