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

» Large Negative Uniaxial Magnetic Anisotropy in Epitaxially Strained Nickel Ferrite Films
Abstract:
We investigated the magnetic properties of NiFe2O4(NFO) epitaxial films grown on MgAl2O4(MAO) substrates by the reactive radio frequency magnetron sputtering method. The films were found to be coherently distorted to at least 61 nm thickness because of the lattice mismatch between MAO and NFO. The NFO(001) films exhibited large negative uniaxial anisotropy that can be quantitatively explained by the magneto-elastic theory despite the lattice distortion being as much as 3%. We also discovered magnetic anomalies in both the saturation magnetization and anisotropy of the thinnest film, which may because of the reconstruction of the electronic structures at NFO interfaces.
Autors: Mitsuharu Matsumoto;Sonia Sharmin;Jun-ichiro Inoue;Eiji Kita;Hideto Yanagihara;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Large System Analysis of Resource Allocation in Heterogeneous Networks With Wireless Backhaul
Abstract:
Small-cell networks and massive multiple-input multiple-output (MIMO) systems are regarded as important candidate techniques for 5G communication systems. This paper considers a heterogeneous network composed of a macrocell tier overlaid with an extremely dense tier of small-cells. In the network, the macrocell base station (BS), which applies massive MIMO, does not only serve macro user equipment units but also provides wireless backhaul for small-cell access points (APs). The wireless backhaul shares the same spectrum resource with radio access networks without creating extra spectrum resources. However, due to the densification of small-cells, the inter- and intra-tier interferences become severe. To mitigate the interferences, we use the regularized zero-forcing precoding combined with a projection technique is used at the BS in downlink (DL) to avoid interference to the APs in uplink (UL). Meanwhile, the joint linear minimum mean square error detection is applied in UL to mitigate the inter-tier interference. We derive deterministic expressions for ergodic UL and DL sum rates (SRs) by leveraging the large-dimensional random matrix theory. The expressions only depend on statistical channel information and can be used to optimize the bandwidth division between radio access links and wireless backhaul, as well as the time allocation between DL and UL operation intervals. Numerical results show that the deterministic SR equivalents are accurate and that the proposed resource allocation method can significantly improve system performance.
Autors: Wenchao Xia;Jun Zhang;Shi Jin;Chao-Kai Wen;Feifei Gao;Hongbo Zhu;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 5040 - 5053
Publisher: IEEE
 
» Layout-Based Test Coverage Verification for High-Reliability Devices
Abstract:
Test quality is critical to eliminate test escapes and to achieve high-reliability large-scale integrated (LSI) devices. This paper proposes a new concept called “physical test coverage” to verify test coverage based on the physical layout of LSI circuits. The physical test coverage is calculated as the ratio between the critical area of all wires in a device and that of wires undetected by LSI tests. From the critical area of undetected wires and the defect density of a manufacturing line, the risk of test escapes can be predicted. To effectively develop LSI tests that can minimize the number of test patterns, undetected wires are prioritized by the critical area related to each wire. Even when the conventional “logical” test coverage is high enough to satisfy the coverage criterion, some LSI devices investigated in this paper showed low physical test coverage depending on the physical layout of the LSI circuit. The concept of physical coverage was applied in the test development of some LSI products, and the test quality was substantially improved, such that 90% of test escapes of a device were eliminated.
Autors: Yoshikazu Nagamura;Kenji Shiozawa;Toru Koyama;Jun Matsushima;Kazuhiro Tomonaga;Yutaka Hoshi;Shuji Nomura;Masayuki Arai;Kazuhiko Iwasaki;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 317 - 322
Publisher: IEEE
 
» Lead-Free Piezoelectric Ceramic Coatings Fabricated by Thermal Spray Process
Abstract:
This paper starts from a review on the progress in fabrication of piezoelectric ceramic coatings by thermal spray method. For our experimental work, two types of lead-free piezoelectric ceramic coatings, including potassium-sodium niobate-based and bismuth sodium titanate-based, are fabricated by thermal spray process, and their structure, morphology, and piezoelectric properties are characterized. Our obtained lead-free ceramic coatings exhibit single phase of perovskite structure, relatively dense morphology, and competitive piezoelectric coefficients. The mechanism of forming the piezoelectric perovskite crystalline phase by thermal spray involving melting-recrystallization process is analyzed in comparison to that of ceramic synthesis through solid-state reaction. Suppression of volatile loss and decomposition at high temperature due to the extremely high melting and cooling rate in the thermal spray process, and the impact on the resulting structure are discussed. Significant advantages of the thermal spray method over alternative processing methods for forming piezoelectric ceramic coatings are summarized. The combination of environmentally friendly lead-free compositions and the scalable thermal spray processing method will promote more applications of piezoelectric ceramic coatings for producing distributive sensors and transducers, and forming advanced smart structures and systems.
Autors: Kui Yao;Shuting Chen;Kun Guo;Chee Kiang Ivan Tan;Meysam Sharifzadeh Mirshekarloo;Francis Eng Hock Tay;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Nov 2017, volume: 64, issue:11, pages: 1758 - 1765
Publisher: IEEE
 
» Leadership Changes in 2018 [Chapter News]
Abstract:
Presents information on various IAS Society chapters.
Autors: Peter Magyar;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 78 - 79
Publisher: IEEE
 
» Leap-Frog Continuous–Discontinuous Galerkin Time Domain Method for Nanoarchitectures With the Drude Model
Abstract:
A continuous–discontinuous Gakerkin time domain method (CDGTD) with vector basis functions is proposed to analyze the wideband response of plasmonic structures with the Drude dispersive model. Compared to the conventional time domain approaches, such as FDTD and PSTD, the unstructured mesh can provide a better geometrical approximation of curved surfaces and fine features. An EB scheme Riemann solver is employed to calculate the flux between adjacent subdomains. The relationship between the electric field and the polarization currents is modeled by a first order auxiliary differential equation (ADE). A leap-frog scheme is proposed to update Maxwell's equations, the ADEs of the Drude medium and the perfectly matched layer (PML) in an efficient manner. This new approach is validated by virtue of simulating the ultra-wideband behavior of a gold nanoloop antenna with and without a substrate as well as the reflectivity of a dual-band infrared absorber. Its advantage in computational cost is demonstrated via comparison to a commercial software package. In this light, the CDGTD method represents a more efficient forward modeling tool, which has been successfully employed here to perform a parametric study of a dual-band infrared absorber.
Autors: Qiang Ren;Yusheng Bian;Lei Kang;Pingjuan L. Werner;Douglas H. Werner;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:22, pages: 4888 - 4896
Publisher: IEEE
 
» Learning Aerial Image Segmentation From Online Maps
Abstract:
This paper deals with semantic segmentation of high-resolution (aerial) images where a semantic class label is assigned to each pixel via supervised classification as a basis for automatic map generation. Recently, deep convolutional neural networks (CNNs) have shown impressive performance and have quickly become the de-facto standard for semantic segmentation, with the added benefit that task-specific feature design is no longer necessary. However, a major downside of deep learning methods is that they are extremely data hungry, thus aggravating the perennial bottleneck of supervised classification, to obtain enough annotated training data. On the other hand, it has been observed that they are rather robust against noise in the training labels. This opens up the intriguing possibility to avoid annotating huge amounts of training data, and instead train the classifier from existing legacy data or crowd-sourced maps that can exhibit high levels of noise. The question addressed in this paper is: can training with large-scale publicly available labels replace a substantial part of the manual labeling effort and still achieve sufficient performance? Such data will inevitably contain a significant portion of errors, but in return virtually unlimited quantities of it are available in larger parts of the world. We adapt a state-of-the-art CNN architecture for semantic segmentation of buildings and roads in aerial images, and compare its performance when using different training data sets, ranging from manually labeled pixel-accurate ground truth of the same city to automatic training data derived from OpenStreetMap data from distant locations. We report our results that indicate that satisfying performance can be obtained with significantly less manual annotation effort, by exploiting noisy large-scale training data.
Autors: Pascal Kaiser;Jan Dirk Wegner;Aurélien Lucchi;Martin Jaggi;Thomas Hofmann;Konrad Schindler;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6054 - 6068
Publisher: IEEE
 
» Learning Contextual-Variability Models
Abstract:
Modeling how contextual factors relate to a software system’s configuration space is usually a manual, error-prone task that depends highly on expert knowledge. Machine-learning techniques can automatically predict the acceptable software configurations for a given context. Such an approach executes and observes a sample of software configurations within a sample of contexts. It then learns what factors of each context will likely discard or activate some of the software’s features. This lets developers and product managers automatically extract the rules that specialize highly configurable systems for specific contexts.
Autors: Paul Temple;Mathieu Acher;Jean-Marc Jézéquel;Olivier Barais;
Appeared in: IEEE Software
Publication date: Nov 2017, volume: 34, issue:6, pages: 64 - 70
Publisher: IEEE
 
» Learning Efficient Binary Codes From High-Level Feature Representations for Multilabel Image Retrieval
Abstract:
Due to the efficiency and effectiveness of hashing technologies, they have become increasingly popular in large-scale image semantic retrieval. However, existing hash methods suppose that the data distributions satisfy the manifold assumption that semantic similar samples tend to lie on a low-dimensional manifold, which will be weakened due to the large intraclass variation. Moreover, these methods learn hash functions by relaxing the discrete constraints on binary codes to real value, which will introduce large quantization loss. To tackle the above problems, this paper proposes a novel unsupervised hashing algorithm to learn efficient binary codes from high-level feature representations. More specifically, we explore nonnegative matrix factorization for learning high-level visual features. Ultimately, binary codes are generated by performing binary quantization in the high-level feature representations space, which will map images with similar (visually or semantically) high-level feature representations to similar binary codes. To solve the corresponding optimization problem involving nonnegative and discrete variables, we develop an efficient optimization algorithm to reduce quantization loss with guaranteed convergence in theory. Extensive experiments show that our proposed method outperforms the state-of-the-art hashing methods on several multilabel real-world image datasets.
Autors: Lei Ma;Hongliang Li;Fanman Meng;Qingbo Wu;King Ngi Ngan;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2545 - 2560
Publisher: IEEE
 
» Learning Online Trends for Interactive Query Auto-Completion
Abstract:
Query auto-completion (QAC) is widely used by modern search engines to assist users by predicting their intended queries. Most QAC approaches rely on deterministic batch learning algorithms trained from past query log data. However, query popularities keep changing all the time and QAC operates in a real-time scenario where users interact with the search engine continually. So, ideally, QAC must be timely and adaptive enough to reflect time-sensitive changes in an online fashion. Second, due to the vertical position bias, a query suggestion with a higher rank tends to attract more clicks regardless of user’s original intention. Hence, in the long run, it is important to place some lower ranked yet potentially more relevant queries to higher positions to collect more valuable user feedbacks. In order to tackle these issues, we propose to formulate QAC as a ranked Multi-Armed Bandits (MAB) problem which enjoys theoretical soundness. To utilize prior knowledge from query logs, we propose to use Bayesian inference and Thompson Sampling to solve this MAB problem. Extensive experiments on large scale datasets show that our QAC algorithm has the capacity to adaptively learn temporal trends, and outperforms existing QAC algorithms in ranking qualities.
Autors: Yingfei Wang;Hua Ouyang;Hongbo Deng;Yi Chang;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Nov 2017, volume: 29, issue:11, pages: 2442 - 2454
Publisher: IEEE
 
» Learning Roadway Surface Disruption Patterns Using the Bag of Words Representation
Abstract:
Accurately classifying roadway surface disruptions (RSDs) plays a crucial role to enhance quality transportation and road safety. To this end, smartphones are becoming an ad hoc tool to collect road data, while the user is at the steering wheel. In this paper, for the first time, sensed data are represented with a novel technique inspired in the bag of words representation. New results suggest that segments of accelerometer readings play a key role to characterize different classes of events, boosting classification performance. A novel data collection process was conducted in real-life environments, where the smartphones were freely placed at five user-surveyed locations, within a fleet of cars and trucks. To the best of our knowledge, this is the largest and most heterogenous data set for RSDs, and we make it publicly available. We approach the problem of identifying RSDs as one of supervised learning, where we contrast representative classifiers, most of them not previously reported. We exhaustively evaluated the performance of all classifiers in six data sets, most of them resembling actual data sets used in similar projects. We found that in all cases, the best classifier outperforms the best results reported so far. The proposed methodology was extensively evaluated through a sensitivity analysis to determine the relevance of the parameters. Experimental results reveal that the representation technique boosts considerably the classification performance when compared with the state of the art solutions, reducing in one order of magnitude the false-positives/negatives rate and surpassing the classification accuracy for about 10% in a multiclass data set.
Autors: Luis C. González;Ricardo Moreno;Hugo Jair Escalante;Fernando Martínez;Manuel Ricardo Carlos;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 2916 - 2928
Publisher: IEEE
 
» Learning-Based Jamming Attack against Low-Duty-Cycle Networks
Abstract:
Jamming is a typical attack by exploiting the nature of wireless communication. Lots of researchers are working on improving energy-efficiency of jamming attack from the attacker’s view. Whereas, in the low-duty-cycle wireless sensor networks where nodes stay asleep most of time, the design of jamming attack becomes even more challenging especially when considering the stochastic transmission pattern arising from both the clock drift and other uncertainties. In this paper, we propose LearJam, a novel learning-based jamming attack strategy against low-duty-cycle networks, which features the two-phase design consisting of the learning phase and attacking phase. Then in order to degrade the network throughput to the maximal degree, LearJam jointly optimizes these two phases subject to the energy constraint. Moreover, such process of optimization is operated iteratively to accommodate the requirement of practical implementation. Conversely, we also discuss how the state-of-the-art mechanisms can defend against LearJam, which will aid the researchers to improve the security of low-duty-cycle networks. Extensive simulations show that our design achieves significantly higher number of successful attacks and reduces the network’s throughput considerably, especially in a sparse low-duty-cycle network, compared with some typical jamming strategies.
Autors: Zequ Yang;Peng Cheng;Jiming Chen;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Nov 2017, volume: 14, issue:6, pages: 650 - 663
Publisher: IEEE
 
» Leech Constellations of Construction-A Lattices
Abstract:
The problem of communicating over the additive white Gaussian noise (AWGN) channel with lattice codes is addressed in this paper. Theoretically, Voronoi constellations have proved to yield very powerful lattice codes when the fine/coding lattice is AWGN-good and the coarse/shaping lattice has an optimal shaping gain. However, achieving Shannon capacity with these premises and practically implementable encoding algorithms is in general not an easy task. In this paper, a new way to encode and demap Construction-A Voronoi lattice codes is presented. As a meaningful application of this scheme, the second part of the paper is focused on Leech constellations of low-density Construction-A (LDA) lattices: LDA Voronoi lattice codes are presented whose numerically measured waterfall region is situated at less than 0.8 dB from Shannon capacity. These LDA lattice codes are based on dual-diagonal nonbinary low-density parity-check codes. With this choice, encoding, iterative decoding, and demapping have all linear complexity in the block length.
Autors: Nicola di Pietro;Joseph J. Boutros;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4622 - 4631
Publisher: IEEE
 
» Line Resistance Reduction in Advanced Copper Interconnects
Abstract:
Line resistance reduction in interconnects was achieved through Cu microstructure modulation. The modulation was performed via both raising annealing temperature and reducing the post-patterning dielectric aspect ratio and resulted in a bamboo-like Cu microstructure. Compared with the conventional polycrystalline, the modulated Cu microstructure also presents a lower resistivity increase rate with area scaling. A TaN stress control layer deposited on over-plated Cu surface was demonstrated to be critical for maintaining the Cu interconnect integrity after the high-temperature anneal.
Autors: C.-C. Yang;T. Standaert;H. Huang;M. Ali;G. Lian;D. Edelstein;G. Bonilla;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1579 - 1582
Publisher: IEEE
 
» Linear Convergence of Stochastic Iterative Greedy Algorithms With Sparse Constraints
Abstract:
Motivated by recent work on stochastic gradient descent methods, we develop two stochastic variants of greedy algorithms for possibly non-convex optimization problems with sparsity constraints. We prove linear convergence1 in expectation to the solution within a specified tolerance. This generalized framework is specialized to the problems of sparse signal recovery in compressed sensing and low-rank matrix recovery, giving methods with provable convergence guarantees that often outperform their deterministic counterparts. We also analyze the settings, where gradients and projections can only be computed approximately, and prove the methods are robust to these approximations. We include many numerical experiments, which align with the theoretical analysis and demonstrate these improvements in several different settings.

Linear convergence is sometimes called exponential convergence.

Autors: Nam Nguyen;Deanna Needell;Tina Woolf;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 6869 - 6895
Publisher: IEEE
 
» Linear Degrees of Freedom of Full-Duplex Cellular Networks With Reconfigurable Antennas
Abstract:
In this paper, we characterize the linear degrees of freedom (DoF) of a cellular network in which the base station (BS) operates in a full-duplex (FD) mode and the users operate in a half-duplex mode. We assume that the BS and the users are equipped with reconfigurable antennas which can be switched between their preset modes. We consider two practical scenarios for different assumptions on channel state information at the transmit sides (CSIT), referred to as no CSIT and partial CSIT models. To derive the inner-bounds for two scenarios, we propose a new achievable scheme which enables interference alignment between uplink and downlink interference signals at each user via preset mode switching of reconfigurable antennas. The key concept of our scheme is to align the interference signals of uplink transmission at the downlink users, through the identical preset mode pattern over the multiple of downlink transmission periods and silence periods of the BS. We also develop an outer-bound on the linear sum DoF of the cellular network for the no CSIT model, which matches up with the inner-bound. Moreover, we also provide a natural variant of the proposed scheme when considering residual self-interference at the FD BS, which can alleviate the shortcoming of the existing self-interference cancellation techniques.
Autors: Heecheol Yang;Wonjae Shin;Jungwoo Lee;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7195 - 7206
Publisher: IEEE
 
» Linear Platform Evaluation in Semiconductor Manufacturing
Abstract:
Equipment productivity in semiconductor manufacturing has become a major topic due to high equipment prices. It is easier and more precise to calculate productivity based on the running logs; however, engineers may often be assigned to estimate the productivity of the equipment in the design phase to predict project benefits so that investment decisions can be made. In such situations, no running log is available to calculate equipment productivity. If the architecture of the equipment and the wafer flow are simple, equipment productivity still can be evaluated using algebra-based solutions. Unfortunately, with rapidly shrinking IC dimensions equipment architecture becomes more and more complicated so a linear platform is typically used. In a linear platform, multiple mainframes are used to install more chambers. In each main-frame, there may be multiple robots to enable efficient wafer transmission. It is very difficult to estimate the productivity of a linear platform using simple algebra-based solutions; however, accurate productivity estimation of a linear platform is critical due to its higher price. To address this problem, a novel estimative methodology is proposed in this paper. This method analyzes the potential wait time of a chamber and then identifies the productivity bottleneck of the platform. The proposed methodology is designed for calculating wafers per hour for the linear platform. The accuracy of the proposed methodology is then verified by a simulation model. By applying this methodology to estimate the productivity for a semiconductor manufacturing line incorrect equipment investment can be reduced, therefore enhancing market competitiveness.
Autors: Kai-Ting Yang;Li-Jen Ko;Hsiang-Yin Shen;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 395 - 401
Publisher: IEEE
 
» Linear Precoder Design for an AF Two-Way MIMO Relay Node with No Source Node Precoding
Abstract:
In this paper, an amplify-and-forward two-way relay (TWR) precoding is designed with no source node (SN) processing in order to maximize sum rate and concurrently reduce the network latency and signaling overhead. For the arbitrary pre-/postprocessing at the SNs that have antennas, it is rigorously shown that an -by- optimal TWR precoder matrix is symmetric when the noise power of the TWR node is relatively small compared with that of the SNs and/or each of the channel matrices is spatially orthogonal. Using the symmetric structure of the TWR precoding matrix, a constrained nonlinear-multivariable optimization problem is formulated that can be solved with polynomial time complexity. Furthermore, a closed-form optimal TWR precoding matrix is designed for a TWR system with . When compared with an optimal joint SN and RN precoding method, it is verified that the proposed precoding method provides a good tradeoff between the system complexity and sum rate performance.
Autors: Jingon Joung;Jihoon Choi;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10526 - 10531
Publisher: IEEE
 
» Linear Programming-Based Converses for Finite Blocklength Lossy Joint Source-Channel Coding
Abstract:
A linear programming (LP)-based framework is presented for obtaining converses for finite blocklength lossy joint source-channel coding problems. The framework applies for any loss criterion, generalizes certain previously known converses, and also extends to multi-terminal settings. The finite blocklength problem is posed equivalently as a nonconvex optimization problem and using a lift-and-project-like method, a close but tractable LP relaxation of this problem is derived. Lower bounds on the original problem are obtained by the construction of feasible points for the dual of the LP relaxation. A particular application of this approach leads to new converses, which recover and improve on the converses of Kostina and Verdú for finite blocklength lossy joint source-channel coding and lossy source coding. For finite blocklength channel coding, the LP relaxation recovers the converse of Polyanskiy, Poor and Verdú and leads to a new improvement on the converse of Wolfowitz, showing thereby that our LP relaxation is asymptotically tight with increasing blocklengths for channel coding, lossless source coding, and joint source-channel coding with the excess distortion probability as the loss criterion. Using a duality-based argument, a new converse is derived for finite blocklength joint source-channel coding for a class of source-channel pairs. Employing this converse, the LP relaxation is also shown to be tight for all blocklengths for the minimization of the expected average symbolwise Hamming distortion of a -ary uniform source over a -ary symmetric memoryless channel for any . The optimization formulation and the lift-and-project method are extended to networked settings and demonstrated - y obtaining an improvement on a converse of Zhou et al. for the successive refinement problem for successively refinable source-distortion measure triplets.
Autors: Sharu Theresa Jose;Ankur A. Kulkarni;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7066 - 7094
Publisher: IEEE
 
» Linear Wireless Strain Sensor Using FeAlB and Amorphous Alloys
Abstract:
In a previous paper, we discussed wireless strain sensors, based upon the effect, employing a number of different field-annealed amorphous ribbons as resonators and transducers. In this paper, we present results for a polycrystalline (Fe0.8Al0.2)98B2 alloy as the transducer and either Metglas 2826MB3 or Beijing Yeke 1K501 as the resonator. Frequency variation curves and tensile stress tests were performed on the sensors. The FeAlB–amorphous alloys ensemble resulted in a linear behavior through a larger deformation amplitude than previously obtained. Gauge factors of up to 190 were obtained over a deformation amplitude of at least 300 ppm. The results are discussed in the light of the magnetization behavior of the materials involved.
Autors: Eduardo S. Bastos;Alessandro Dalponte;Frank P. Missell;Guilherme O. Fulop;Mateus B. de Souza Dias;Cristina Bormio-Nunes;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Liquid Sensors Based on Enhanced Fabry–Perot Etalons
Abstract:
An optically enhanced Fabry–Perot etalon was demonstrated to accurately measure the refractive index of sugar solutions. The etalon consisted of two silver/SiO2-coated glass substrates separated by a spacer. The semi-transparent silver films of ~15-nm thickness greatly enhanced the interference of light. The SiO2 layer coated on the silver created a hydrophilic surface in addition to protecting the silver from oxidation. The hydrophilic behavior of the SiO2 films together with a capillary action allowed the tested liquids to easily flow into and wet the cavity between the two pieces of glass. Optical spectrophotometer was used to measure the transmission spectra of the etalon with and without a sugar solution. The refractive indices of sugar solutions with different brix concentrations were subsequently determined from the interference peak positions. The results showed a linear response of the refractive index to the brix concentration with a ratio of refractive index per brix%, making the etalons promising for analyzing specific chemicals in liquids.
Autors: Nezam Uddin;Maheshwar Shrestha;Bocong Zheng;Hyeun-Joong Yoon;Xiuqing Wang;Qi Hua Fan;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7348 - 7354
Publisher: IEEE
 
» Lithographic Source and Mask Optimization With Low Aberration Sensitivity
Abstract:
Source and mask optimization (SMO) is an important lithographic resolution enhancement technology. Recently, some research indicate that the lithography performance is sensitive to the errors of an actual lithography system, such as thermal aberration, thick mask effects, and mask uncertainties. Most of the errors would result in uncertain wavefront aberration, so the reduction of aberration sensitivity means the improvement of lithography stability. In this paper, we propose a low aberration sensitivity SMO (LASSMO) method to improve robustness of lithography performance against uncertain aberration. To reduce the aberration sensitivity, we build the LASSMO model via innovating new cost function including sensitivity penalty terms. Aiming at spherical aberration and coma, this method is demonstrated using two target patterns with critical dimensions of 45 nm. Taking into account the statistic characteristics of uncertain aberration, we use the normalized stochastic gradient descent algorithm to establish an iterative optimization framework. The simulation results show the benefit of LASSMO method in both high pattern fidelity and the low sensitivity of lithography imaging to aberration.
Autors: Tie Li;Yanqiu Li;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 1099 - 1105
Publisher: IEEE
 
» Littelfuse Celebrates 90 Years of Protecting the World [History]
Abstract:
You've never heard of Littelfuse? Do you drive a car or truck? Do you watch TV or use a laptop computer or a mobile device? Do you use a washing machine or dryer for clothes, or do you adjust the temperature in your home? Assuming your answer is ?yes? to any or all of these questions, then you have and continue to use Littelfuse products on a daily basis.
Autors: Dave Scheuerman;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 9 - 77
Publisher: IEEE
 
» LO Generation With a Phase Interpolator Digital-to-Time Converter
Abstract:
This paper shows the generation of a local oscillator (LO) signal for cellular transceivers by means of a phase-locked loop and a phase interpolator (PI) digital-to-time converter (DTC). The PI-DTC allows arbitrary frequency shifts over a wide range. We derive a closed-form description of the spurs in the spectrum of the LO signal caused by quantization and nonlinear effects for the PI-DTC. Furthermore, we show the existence of a new class of spurs generated due to noise processes in the PI. Measurement and simulation results are in good agreement with our closed-form solution.
Autors: Peter Preyler;Christoph Preissl;Stefan Tertinek;Tobias Buckel;Andreas Springer;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4669 - 4676
Publisher: IEEE
 
» Load Balanced Mobile User Recruitment for Mobile Crowdsensing Systems
Abstract:
In this letter, we study the mobile user recruitment problem for mobile crowdsensing systems. Instead of minimizing the overall sensing cost or user utility, this letter aims to optimize the load balancing of the mobile users, which is particularly important for the resource-constrained individual user. We refer to such a problem as the load balanced mobile user recruitment (LB-MUR) problem. Specifically, we first formulate the LB-MUR problem as a mixed integer linear programming (LP) and prove that it is NP-hard. Then an efficient polynomial-time suboptimal algorithm is proposed, which is based on LP relaxation. Furthermore, we derive the approximation ratio of the proposed algorithm. Finally, we evaluate the effectiveness of the proposed scheme through simulations.
Autors: Xin An;Hao Guo;Xiumin Wang;Xiaoming Chen;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2420 - 2423
Publisher: IEEE
 
» Local Discriminant Canonical Correlation Analysis for Supervised PolSAR Image Classification
Abstract:
This letter proposes a novel multiview feature extraction method for supervised polarimetric synthetic aperture radar (PolSAR) image classification. PolSAR images can be characterized by multiview feature sets, such as polarimetric features and textural features. Canonical correlation analysis (CCA) is a well-known dimensionality reduction (DR) method to extract valuable information from multiview feature sets. However, it cannot exploit the discriminative information, which influences its performance of classification. Local discriminant embedding (LDE) is a supervised DR method, which can preserve the discriminative information and the local structure of the data well. However, it is a single-view learning method, which does not consider the relation between multiple view feature sets. Therefore, we propose local discriminant CCA by incorporating the idea of LDE into CCA. Specific to PolSAR images, a symmetric version of revised Wishart distance is used to construct the between-class and within-class neighboring graphs. Then, by maximizing the correlation of neighboring samples from the same class and minimizing the correlation of neighboring samples from different classes, we find two projection matrices to achieve feature extraction. Experimental results on the real PolSAR data sets demonstrate the effectiveness of the proposed method.
Autors: Xiayuan Huang;Bo Zhang;Hong Qiao;Xiangli Nie;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2102 - 2106
Publisher: IEEE
 
» Locality Adaptive Discriminant Analysis for Spectral–Spatial Classification of Hyperspectral Images
Abstract:
Linear discriminant analysis (LDA) is a popular technique for supervised dimensionality reduction, but with less concern about a local data structure. This makes LDA inapplicable to many real-world situations, such as hyperspectral image (HSI) classification. In this letter, we propose a novel dimensionality reduction algorithm, locality adaptive discriminant analysis (LADA) for HSI classification. The proposed algorithm aims to learn a representative subspace of data, and focuses on the data points with close relationship in spectral and spatial domains. An intuitive motivation is that data points of the same class have similar spectral feature and the data points among spatial neighborhood are usually associated with the same class. Compared with traditional LDA and its variants, LADA is able to adaptively exploit the local manifold structure of data. Experiments carried out on several real hyperspectral data sets demonstrate the effectiveness of the proposed method.
Autors: Qi Wang;Zhaotie Meng;Xuelong Li;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2077 - 2081
Publisher: IEEE
 
» Localization by Fusing a Group of Fingerprints via Multiple Antennas in Indoor Environment
Abstract:
Most existing fingerprints-based indoor localization approaches are based on some single fingerprint, such as received signal strength (RSS), channel impulse response, and signal subspace. However, the localization accuracy obtained by the single fingerprint approach is rather susceptible to the changing environment, multipath, and non-line-of-sight propagation. In this paper, we propose a novel localization framework by Fusing A Group Of fingerprinTs (FAGOT) via multiple antennas for the indoor environment. We first build a GrOup Of Fingerprints (GOOF), which includes five different fingerprints, namely, RSS, covariance matrix, signal subspace, fractional low-order moment, and fourth-order cumulant, which are obtained by different transformations of the received signals from multiple antennas in the offline stage. Then, we design a parallel GOOF multiple classifiers based on AdaBoost (GOOF-AdaBoost) to train each of these fingerprints in parallel as five strong multiple classifiers. In the online stage, we input the corresponding transformations of the real measurements into these strong classifiers to obtain independent decisions. Finally, we propose an efficient combination fusion algorithm, namely, MUltiple Classifiers mUltiple Samples (MUCUS) fusion algorithm to improve the accuracy of localization by combining the predictions of multiple classifiers with different samples. As compared with the single fingerprint approaches, our proposed approach can improve the accuracy and robustness of localization significantly. We demonstrate the feasibility and performance of the proposed algorithm through extensive simulations as well as via real experimental data using a Universal Software Radio Peripheral platform with four antennas.
Autors: Xiansheng Guo;Nirwan Ansari;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9904 - 9915
Publisher: IEEE
 
» LoCCo-Based Scan Chain Stitching for Low-Power DFT
Abstract:
Power dissipation during scan testing of a system-on-chip can be significantly higher than that during functional mode, causing reliability and yield concerns. This paper proposes a logic cluster controllability (LoCCo)-based scan chain stitching methodology to achieve low-power testing. The scan chain stitching is made power aware by placing flip-flops with higher test combination requirements at the beginning of scan chains, while flip-flops with lower test combination requirements are put toward the end of scan chains. The test combination requirements are estimated through a simple logic cluster and flip-flop controllability identification algorithm. This method helps in consolidating care bits toward the beginning of scan chains. Hence, a significantly lower shift-in transition is achieved in the test patterns. The results from ITC’99 and industrial designs in 28FDSOI and 40-nm CMOS technologies show a total shift-in transition reduction of up to 23.1% and average shift power reduction of up to 21.6% using the proposed method. The use of LoCCo methodology posed a negligible routing congestion overhead in the layout compared to the conventional method. LoCCo is also used as a base to apply other vector reordering low-power methods and gain reduced computation time with almost similar power reduction as achieved by Bonhomme et al. independently.
Autors: Shalini Pathak;Anuj Grover;Mausumi Pohit;Nitin Bansal;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 3227 - 3236
Publisher: IEEE
 
» Logic Design Partitioning for Stacked Power Domains
Abstract:
Energy and battery lifetime constraints are critical challenges to IC designs. Stacked power-domain implementation, which connects voltage domains in series, can effectively improve power delivery efficiency and thus improve battery lifetime. However, such an approach requires balanced currents between different domains across multiple operating scenarios. Furthermore, level shifter insertion, along with placement constraints imposed by power domain regions, can incur significant power and area penalties. To the best of our knowledge, no existing work performs subblock-level partitioning optimization for stacked-domain designs. In this paper, we present an optimization framework for stacked-domain designs. Based on an initial placement solution, we apply a flow-based partitioning that is aware of multiple operating scenarios, cell placement, and timing-critical paths to partition cells into two power domains with balanced cross-domain current and minimized number of inserted level shifters. We further propose heuristics to define regions for each power domain so as to minimize placement perturbation, as well as a dynamic programming-based method to minimize the area cost of power domain generation. In an updated floor plan, we perform matching-based optimization to insert level shifters with minimized wirelength penalty. Overall, our method achieves an excellent current balance across stacked domains with less than 10% discrepancy, which results in up to more than battery lifetime improvements.
Autors: Kristof Blutman;Hamed Fatemi;Ajay Kapoor;Andrew B. Kahng;Jiajia Li;José Pineda de Gyvez;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 3045 - 3056
Publisher: IEEE
 
» Looking Backward [From the Editor's Desk]
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Alfy Riddle;
Appeared in: IEEE Microwave Magazine
Publication date: Nov 2017, volume: 18, issue:7, pages: 6 - 8
Publisher: IEEE
 
» Loss Calculation and Temperature Field Analysis of Consequent-Pole Hybrid Excited Vernier Machine
Abstract:
This paper investigates the loss and temperature field distributions of a consequent-pole hybrid excited vernier machine (CPHEVM) with dc field windings embedded between the modulating poles. The time-stepping finite-element method is utilized to analyze the losses in consideration of rotating magnetic flux excitation. A 3-D coupled fluid heat transfer model totally packaged in a large air region is established based on the finite volume method to obtain precise temperature rise distribution. A 12-slot/70-pole CPHEVM, which has high torque density and good flux-weakening capability, is taken as an example to reveal the variation patterns of loss and temperature rise under different dc excitations.
Autors: Haitao Wang;Shuhua Fang;Hui Yang;Heyun Lin;Yibo Li;Ling Qin;Yuru Zhou;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Lossless Compression of Medical Images Using 3-D Predictors
Abstract:
This paper describes a highly efficient method for lossless compression of volumetric sets of medical images, such as CTs or MRIs. The proposed method, referred to as 3-D-MRP, is based on the principle of minimum rate predictors (MRPs), which is one of the state-of-the-art lossless compression technologies presented in the data compression literature. The main features of the proposed method include the use of 3-D predictors, 3-D-block octree partitioning and classification, volume-based optimization, and support for 16-b-depth images. Experimental results demonstrate the efficiency of the 3-D-MRP algorithm for the compression of volumetric sets of medical images, achieving gains above 15% and 12% for 8- and 16-bit-depth contents, respectively, when compared with JPEG-LS, JPEG2000, CALIC, and HEVC, as well as other proposals based on the MRP algorithm.
Autors: Luís F. R. Lucas;Nuno M. M. Rodrigues;Luis A. da Silva Cruz;Sérgio M. M. de Faria;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2250 - 2260
Publisher: IEEE
 
» Low Delay Random Linear Coding and Scheduling Over Multiple Interfaces
Abstract:
High-performance real-time applications, expected to be of importance in the upcoming 5G era, such as virtual and augmented reality or tele-presence, have stringent requirements on throughput and per-packet in-order delivery delay. Use of multipath transport is gaining momentum for supporting these applications. However, building an efficient, low latency multipath transfer mechanism remains highly challenging. The primary reason for this is that the delivery delay along each path is typically uncertain and time-varying. When the transmitter ignores the stochastic nature of the path delays, then packets sent along different paths frequently arrive out of order and need to be buffered at the receiver to allow in-order delivery to the application. In this paper, we propose Stochastic Earliest Delivery Path First (S-EDPF), a generalization of EDPF which takes into account uncertainty and time-variation in path delays yet has low-complexity suited to practical implementation. Moreover, we integrate a novel low-delay Forward Error Correction (FEC) scheme into S-EDPF in a principled manner by deriving the optimal schedule for coded packets across multiple paths. Finally, we demonstrate, both analytically and empirically, that S-EDPF is effective at mitigating the delay impact of reordering and loss in multipath transport protocols, offering substantial performance gains over the state of the art.
Autors: Andres Garcia-Saavedra;Mohammad Karzand;Douglas J. Leith;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3100 - 3114
Publisher: IEEE
 
» Low Power Microwave Signal Detection With a Spin-Torque Nano-Oscillator in the Active Self-Oscillating Regime
Abstract:
A spin-torque nano-oscillator (STNO) driven by a ramped bias current can perform spectrum analysis quickly over a wide frequency bandwidth. The STNO spectrum analyzer operates by injection locking to external microwave signals and produces an output dc voltage that temporally encodes the input spectrum. We found, via numerical analysis with a macrospin approximation, that an STNO is able to scan a 10 GHz bandwidth in less than 100 ns (scanning rate exceeds 100 MHz/ns). In contrast to conventional quadratic microwave detectors, the output voltage of the STNO analyzer is proportional to the amplitude of the input microwave signal with sensitivity . The minimum detectable signal of the analyzer depends on the scanning rate and, at low , is about 1 pW.
Autors: Steven Louis;Vasyl Tyberkevych;Jia Li;Ivan Lisenkov;Roman Khymyn;Elena Bankowski;Thomas Meitzler;Ilya Krivorotov;Andrei Slavin;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Low-Complexity Early Termination Method for Rateless Soft Decoder
Abstract:
We propose a new early termination method (ETM) with low computational complexity for Luby transform belief propagation (BP) decoder. The proposed method, which we call least reliable messages (LRM) ETM, observes only sign alterations of a small cluster in log-likelihood ratio messages passing between nodes in BP decoder. Simulation results and complexity analyzes show that LRM ETM has quite low computational complexity and small average iteration amounts without any performance degradation compared with conventional ETMs in literature. The method can be applied to code families which can be decoded by BP such as low density parity check codes, polar codes, and Raptor codes.
Autors: Cenk Albayrak;Cemaleddin Simsek;Kadir Turk;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2356 - 2359
Publisher: IEEE
 
» Low-Complexity Methodology for Complex Square-Root Computation
Abstract:
In this brief, we propose a low-complexity methodology to compute a complex square root using only a circular coordinate rotation digital computer (CORDIC) as opposed to the state-of-the-art techniques that need both circular as well as hyperbolic CORDICs. Subsequently, an architecture has been designed based on the proposed methodology and implemented on the ASIC platform using the UMC 180-nm Technology node with 1.0 V at 5 MHz. Field programmable gate array (FPGA) prototyping using Xilinx’ Virtex-6 (XC6v1x240t) has also been carried out. After thorough theoretical analysis and experimental validations, it can be inferred that the proposed methodology reduces 21.15% slice look up tables (on FPGA platform) and saves 20.25% silicon area overhead and decreases 19% power consumption (on ASIC platform) when compared with the state-of-the-art method without compromising the computational speed, throughput, and accuracy.
Autors: Suresh Mopuri;Amit Acharyya;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 3255 - 3259
Publisher: IEEE
 
» Low-Frequency and Broadband Vibration Energy Harvesting Using Base-Mounted Piezoelectric Transducers
Abstract:
Piezoelectric vibration energy harvesters often consist of a cantilevered beam composed of a support layer and one or two piezoelectric layers with a tip mass. While this configuration is advantageous for maximizing electromechanical coupling, the mechanical properties of the piezoelectric material can place limitations on harvester size and resonant frequency. Here, we present numerical and experimental results from a new type of piezoelectric energy harvester in which the mechanical properties and the resonant frequency of the cantilever beam resonator are effectively decoupled from the piezoelectric component. Referred to as a base-mounted piezoelectric (BMP) harvester in this paper, this new design features a piezoelectric transducer mounted beneath the base of the cantilevered beam resonator. The flexibility in the material choice for the cantilever beam resonator means that the resonant frequency and the beam dimensions are essentially free parameters. A prototype made with a 1.6 mm mm mm polyurethane beam, a PZT-5H piezoelectric transducer, and an 8.36-g tip mass is shown to produce an average power of 8.75 and at 45 Hz across a 13.0- load under harmonic base excitations of constant peak acceleration at 0.25 and 1.0-g, respectively. We also show an increase in full-width half-maximum bandwidth approximately from 1.5 to 5.6 Hz using an array of four individual BMP harvesters of similar dimensions with peak power generation of at 37.6 Hz across a 1.934- load at 0.25-g peak base excitation. Finite elements-based numerical simulations are shown to be in reasonable agreement with experimental results, indicating that the harvester behaves like a damped mass–spring system as proposed in this paper. Fabricated using casting and laser machining techniques, this harvester shows potential as a low-cost option for powering small, low-power wireless sensor nodes and other low-power devices.
Autors: Robert Koven;Matthew Mills;Richard Gale;Burak Aksak;
Appeared in: IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control
Publication date: Nov 2017, volume: 64, issue:11, pages: 1735 - 1743
Publisher: IEEE
 
» Low-Frequency Noise in High-Mobility a-InGaZnO/InSnO Nanowire Composite Thin-Film Transistors
Abstract:
In this letter, high-performance amorphous indium–gallium–zinc-oxide (a-InGaZnO) and indium–tin-oxide (ITO) nanowire (NW) composite thin-film transistors (TFTs) are fabricated via a sol–gel approach. By incorporating 0.5 wt% ITO NWs into the a-InGaZnO thin film, the composite TFTs can achieve an enhanced field-effect mobility of 76.5 cm2/ and a high current density of with 10- channel length. The low-frequency noise (LFN) characteristic of the composite TFTs fits the classical 1/ noise model very well in the frequency range 1 to 1000 Hz. The subthreshold slope and LFN results provide an alternative explanation to the enhanced performance of the composite TFTs due to the decreased interfacial trap density. The a-InGaZnO/ITO NW composite TFTs are one of the promising candidates for the development of high-speed low-cost electronics.
Autors: Da Wan;Ablat Abliz;Meng Su;Chuangsheng Liu;Changzhong Jiang;Guoli Li;Huipeng Chen;Tailiang Guo;Xingqiang Liu;Lei Liao;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1540 - 1542
Publisher: IEEE
 
» Low-Frequency Noise in III–V Nanowire TFETs and MOSFETs
Abstract:
We present a detailed analysis of low-frequency noise (LFN) measurements in vertical III–V nanowire tunnel field-effect transistors (TFETs), which help to understand the limiting factors of TFET operation. A comparison with LFN in vertical metal-oxide semiconductor field-effect transistors with the same channel material and gate oxide shows that the LFN in these TFETs is dominated by the gate oxide properties, which allowed us to optimize the TFET tunnel junction without deteriorating the noise performance. By carefully selecting the TFET heterostructure materials, we reduced the inverse subthreshold slope well below 60 mV/decade for a constant LFN level.
Autors: Markus Hellenbrand;Elvedin Memišević;Martin Berg;Olli-Pekka Kilpi;Johannes Svensson;Lars-Erik Wernersson;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1520 - 1523
Publisher: IEEE
 
» Low-Noise Amplifier Protection Switch Using p-i-n Diodes With Tunable Open Stubs for Solid-State Pulsed Radar
Abstract:
In this letter, a tunable protection switch device using open stubs for -band low-noise amplifiers (LNAs) is proposed. The protection switch is implemented using p-i-n diodes. As the parasitic inductance in the p-i-n diodes may degrade the protection performance, tunable open stubs are attached to these diodes to obtain a grounding effect. The performance is optimized for the desired frequency band by adjusting the lengths of the microstrip line open stubs. The designed LNA protection switch is fabricated and measured, and sufficient isolation is obtained for a 200 MHz operating band. The proposed protection switch is suitable for solid-state power amplifier radars in which the LNAs need to be protected from relatively long pulses.
Autors: Se-Yeon Jeon;Konstantin Nikitin;Aulia Dewantari;Jaeheung Kim;Min-Ho Ka;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 1004 - 1006
Publisher: IEEE
 
» Low-Power 19-Transistor True Single-Phase Clocking Flip-Flop Design Based on Logic Structure Reduction Schemes
Abstract:
In this paper, an ultralow-power true single-phase clocking flip-flop (FF) design achieved using only 19 transistors is proposed. The design follows a master–slave-type logic structure and features a hybrid logic design comprising both static-CMOS logic and complementary pass-transistor logic. In the design, a logic structure reduction scheme is employed to reduce the number of transistors for achieving high power and delay performance. Despite its circuit simplicity, no internal nodes are left floating during the operation to avoid leakage power consumption. In this design, a virtual design technique, which facilitates a faster state transition in the slave latch, is devised to enhance time performance. In circuit implementation, transistor sizes are optimized with respect to the power-delay product (PDP). A TSMC 90-nm CMOS process was selected as the implementation technology. In this paper, the performance levels of seven FF designs were compared. The timing parameters of each FF were first characterized. Post-layout simulation results indicated that the proposed design excelled in various performance indices such as PDP, clock-to-Q delay, average power consumption, and leakage power consumption. Moreover, the design was determined to have the smallest layout area. Compared with the conventional transmission-gate-based FF design, the PDP improvement in the proposed design was up to 63.5% (at 12.5% switching activity) and the area saving was approximately 10%. Further simulations on process corners, supply voltage settings, and working frequencies were conducted to study the design reliability.
Autors: Jin-Fa Lin;Ming-Hwa Sheu;Yin-Tsung Hwang;Chen-Syuan Wong;Ming-Yan Tsai;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 3033 - 3044
Publisher: IEEE
 
» Low-Power Highly Sensitive pH Sensor With $mu$ dots Protective Structures for Monitoring Rumen in Cows in Real-Time
Abstract:
In this paper, we describe the development of a solid-type pH sensor with an ultra-low power consumption of mAh per measurement and a reasonably high accuracy of 0.1 pH for the real-time monitoring of the rumen of a cow. The sensor combines a metal-oxide-semiconductor field-effect transistor with a separate gate as the sensing electrode, and was fabricated using indium tin oxide with an optimized capture structure that incorporates protective micro-fabricated dots. The evaluation results show that the sensor has high-sensitivity of /pH, and maintains a stable baseline at pH 7 over the course of several days in the rumen. We performed a comprehensive calibration of the solid pH sensor, and carried out a field test, which clearly demonstrated that the pH values are strongly dependent on the activities of the cow, as recorded by a camera. The developed pH sensor is believed to be of significance for preventing disease, as well as for improving the efficiency of food production.
Autors: Lan Zhang;Jian Lu;Hironao Okada;Hirofumi Nogami;Toshihiro Itoh;Shozo Arai;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7281 - 7289
Publisher: IEEE
 
» Low-Profile Two-Arm Inverted-L Antenna Design for Vehicular HF Communications
Abstract:
Design of an electrically small, low-profile vehicular on-the-move (OTM) wideband high frequency antenna with 24 kHz instantaneous-tuned bandwidth is discussed for near vertical incidence skywave (NVIS) communications. Improvement in performance is obtained by applying multiarming and offset feed antenna modifications. These allow for attaining the desired gain >−20 dBi at 3 MHz with a lower profile compared to traditional OTM 3 kHz bandwidth antennas. Specifically, the addition of the second arm improves the bandwidth, whereas NVIS gain is enhanced by offset feeding. The electrical dimensions of the proposed two-arm design over the platform are (H) at the lowest frequency of operation. Antenna performance and achieved benefits under the condition of mechanical breakdown are also discussed. The scaled prototype of the proposed antenna mounted on a selected vehicular platform is built using additive manufacturing. Measurement results agree well with simulations thereby verifying the design procedure and all the discussed findings.
Autors: Saurabh A. Sanghai;Maxim Ignatenko;Dejan S. Filipovic;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5710 - 5719
Publisher: IEEE
 
» Machine Learning and Financial Planning
Abstract:
One of the top recent events in machine learning (ML) involves Google's Alpha Go System beating the world's best player Ke Jie, while experts had predicted that Go (which is considered by many to be the world's most advanced board game) was too complex to be conquered by a computer for a decade or more. What are the main ideas underlying ML algorithms? What can be expected in the area of financial planning vis-a-vis ML? Will there be major disruptions in financial services?
Autors: John M. Mulvey;
Appeared in: IEEE Potentials
Publication date: Nov 2017, volume: 36, issue:6, pages: 8 - 13
Publisher: IEEE
 
» Machine Vision-Based Positioning and Inspection Using Expectation–Maximization Technique
Abstract:
Precision positioning is very important for automatic assembly and inspection in the electronic manufacturing process. In this paper, we propose a fast image alignment method using the expectation-maximization (E-M) technique. The proposed algorithm is especially applied to positioning and defect inspection of printed circuit boards (PCBs). It can well handle deformed or incomplete object shapes with translation, rotation, and scale changes. The Canny edge detector is used to generate the edge maps of images. The E-step of the E-M procedure finds mutual edge points in both compared images by assigning weights to individual edge points. The mutual edge points give larger weights, while the foreign edge points in two images have smaller weights. The M-step then calculates the geometric transformation parameters using the weighted edge points in individual images. For an edge point in one image, a fast spiral search is proposed to find its corresponding edge point with the shortest distance in the other image. The spiral search is carried out by a predetermined lookup table, and no computation is involved in the search process. The weight of each edge point is inversely proportional to the neighboring distance. Experimental results indicate that the proposed E-M positioning method can achieve a translation error less than 1 pixel and a rotation error smaller than 1° for PCB positioning.
Autors: Du-ming Tsai;Yi-chun Hsieh;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 2858 - 2868
Publisher: IEEE
 
» Magnet Eddy-Current Loss Analysis of Interior PM Machines for Electric Vehicle Application
Abstract:
The magnet eddy-current losses of six interior permanent magnet (IPM) machines are investigated for electric vehicle applications in this paper. The armature field, eddy-current density of magnet, the influence of PM depth, the distance of PM layers, and the number of PM segmentation are studied by finite-element analysis. It is demonstrated that increasing the PM depth of first layer and the distance of PM layers can provide more soft iron space for the armature-reaction flux, which can reduce the magnet eddy-current loss. PM segmentation can effectively reduce the PM eddy-current loss, because the eddy-current paths are divided into smaller loops, increasing the effective resistance. An IPM machine with segmented PM is prototyped to verify the analysis.
Autors: Yaohua Hu;Shushu Zhu;Chuang Liu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Behavior of Polycrystalline Gadolinium Subjected to a Magneto-Thermal Protocol
Abstract:
Magneto-thermal (M-T) hysteresis is studied in polycrystalline gadolinium (Gd). The change of the sign of the first anisotropy constant leads to easy cones of magnetization below the spin-reorientation temperature ( K). Cooling a polycrystalline Gd sample in a magnetic field through the spin-reorientation temperature creates magnetic structures which persist to temperatures close to the Curie temperature, if these structures are not erased by going to fields larger than the cooling field. An M-T protocol is applied to give some systematics to these complex processes.
Autors: Virgil Provenzano;Anthony S. Arrott;Hatem ElBidweihy;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Magnetic Characteristics of CuCr2S4 Nanospinels Obtained by Mechanical Alloying and Heat Treatment
Abstract:
Chalcogenide bulk spinels with general formula CuCr2X4 (X = S, Se, and Te) are ferromagnetic and p-type metallic materials with the thermoelectric figure of merit of 0.15. They can be used to dope or alloy with related semiconducting spinels. Therefore, it is expected that their nanosized crystallites display also unique properties and new potential applications. This paper presents the results of dc and ac magnetic measurements, including the higher harmonics of ac magnetic susceptibility as well as electrical conductivity and thermoelectric power of the CuCr2S4 nanospinels. These studies showed that decreasing the size of crystallites to nanometer scale leads to a dramatic change in their physical properties.
Autors: E. Maciążek;E. Malicka;M. Karolus;J. Panek;Z. Stokłosa;T. Groń;A. Gudwański;B. Sawicki;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Magnetic Composite Hydrodynamic Pump With Laser-Induced Graphene Electrodes
Abstract:
A polymer-based magnetohydrodynamic pump capable of actuating saline fluids is presented. The benefit of this pumping concept to operate without any moving parts is combined with simple and cheap fabrication methods and a magnetic composite material, enabling a high level of integration. The operating principle, fabrication methodology, and flow characteristics of the pump are detailed. The pump electrodes are created by laser printing of polyimide, while the permanent magnet is molded from an NdFeB powder–polydimethylsiloxane (PDMS) composite. The cross section area of the pump is 240 mm2. The electrode length is 5 mm. The magnetic characteristics of the NdFeB–PDMS composite indicate high degree of magnetization, which increases the pump efficiency. Using a saline solution similar to seawater, the pump produces 3.4 mm/s flow velocity at a voltage of 7.5 V and a current density of 30 mA/cm2.
Autors: Mohammed Asadullah Khan;Ilija R. Hristovski;Giovanni Marinaro;Jürgen Kosel;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Core-Size Distribution of Magnetic Nanoparticles Estimated From Magnetization, AC Susceptibility, and Relaxation Measurements
Abstract:
The magnetic core-size distribution of magnetic nanoparticles (MNPs) was estimated from three independent measurements, i.e., magnetization, ac susceptibility (ACS), and magnetic relaxation (MRX). First, distribution of magnetic moment m in MNP sample was estimated by analyzing the static magnetization (– curve of the MNP sample in suspension. Next, distribution of anisotropy energy E was estimated by analyzing the ACS of immobilized MNP sample measured from 10 Hz to 1 MHz. The ACS measurement in much lower frequency range was substituted by the MRX measurement. MRX of immobilized MNP sample was measured from 2 to s, corresponding to the frequency range from to 0.5 Hz in ACS measurement. The relaxation curve was analyzed using a newly developed analytical method to estimate the E distribution of the MNPs in the range of large E values. Then, the estimated distributions of m and E were transferred to the distributions of magnetic core size. Core-size distributions obtained from m and E distributions reasonably agreed with each other. Namely, we obtained similar core-size distribution from static and dynamic properties of MNP sample, confirming the validity of the present method. Therefore, the present method can be useful to estimate the core-size distribution of MNP sample.
Autors: Ahmed L. Elrefai;Teruyoshi Sasayama;Takashi Yoshida;Keiji Enpuku;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Magnetic Dead Layers in La0.7Sr0.3MnO3 Revisited
Abstract:
The magnetic dead layers in films a few nanometers thick are investigated for La0.7Sr0.3MnO3 on SrTiO3(STO), LaAlO3(LAO), and (LaAlO3)0.3(Sr2TaAlO6)0.7 (LSAT) substrates. An anomalous moment found to persist above the Curie temperature of the La0.7Sr0.3MnO3 films is not attributed to the films, but to oxygen vacancies at or near the surface of the substrate. The contribution to the moment from the substrate is as high as /nm2 in the case of STO or LSAT. The effect is increased by adding an STO cap layer. Taking this d-zero magnetism into account, extrapolated magnetic dead-layer thicknesses of 0.8, 1.5, and 3 nm are found for the manganite films grown on LSAT, STO, and LAO substrates, respectively. An STO cap layer eliminates the LSMO dead layer.
Autors: S. B. Porter;M. Venkatesan;P. Dunne;B. Doudin;K. Rode;J. M. D. Coey;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Field Analysis for Dimensional Resonance in Mn–Zn Ferrite Toroidal Core and Comparison With Permeability Measurement
Abstract:
This paper studies the calculation method of core loss and magnetic state in Mn–Zn ferrites under an arbitrary waveform excitation. The effective dielectric constant, which is caused by a thin high-resistive layer at the grain boundary, is treated as a modification of Ohm’s law by using an equivalent circuit. This procedure enables us to calculate both the dimensional resonance and eddy-current loss. To confirm the accuracy of the proposed model, the size dependence of the complex permeability and core loss of the toroidal core is analyzed. These results show a good agreement with the experimental measurement in the megahertz region. By using the same model, the core loss mechanism excited by a triangular-wave current is analyzed. In the low-frequency region, the core loss is suppressed by the reduction of a steep change in magnetic flux. However, the core loss near the resonant frequency is increased at the turning point of the current wave, where the time derivative of the current changes discontinuously and a higher harmonic component is induced.
Autors: Atsushi Furuya;Yuji Uehara;Koichi Shimizu;Jun Fujisaki;Tadashi Ataka;Tomohiro Tanaka;Hirotaka Oshima;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Field Dependence of Ni Nanorod Brownian Relaxation
Abstract:
AC magnetic susceptibility and optical transmission measurements were performed on Ni nanorod suspensions for ac and superimposed dc magnetic fields up to 9 mT. With the comparably large magnetic moment per nanorod, these field values correspond to Langevin parameters up to about 80. These wide range of values, the narrow size distribution, and the absence of Néel relaxation make these single-domain ferromagnetic nanorods ideally suited for the experimental verification of the dependence of the Brownian relaxation time on ac and dc magnetic fields. Consistent results for the magnetic moment m and the zero-field Brownian relaxation time were obtained for all measurement modalities and the valid field range of alternative models for the ac susceptibility was evaluated.
Autors: Hilke Remmer;Micha Gratz;Andreas Tschöpe;Frank Ludwig;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Field Distortion From Conductive Layers for High-Frequency Speed Sensor Applications
Abstract:
In previous works, the known scalar approach for the vector potential was extended to determine the influences of eddy currents in metallic layers in a closed form, based on a connection between infinite integrals of Bessel functions and the complete elliptic integrals. While the original idea treats only thin layers with respect to the penetration depth, in this paper, the formalism is extended to the opposite limit of thick layers. It was shown that the developed formalism can be used as a framework to analyze and classify the development of eddy currents in speed sensor systems and even to advocate on chip layout. This extension to thick layers is of great interest in this context as it describes the regime where eddy currents strongly influence the sensor output signal.
Autors: Bernd Filipitsch;Michael Ortner;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Fluorescent Nanoparticles Binding to Amyloid-Beta Peptide: Silica-Coated, Thioflavin-T Functionalized Iron Oxide
Abstract:
Formation and accumulation of extracellular amyloid-beta ( peptide aggregates in the brain are associated with Alzheimer’s disease, a widespread age-related form of dementia, for which there is no effective treatment at present. It is essential to discover ways of visualizing and monitoring the progress of aggregation toward amyloidic plaques while at the same time therapeutic methods inhibiting the aggregation can be explored. Iron oxide nanoparticles Fe3O4 with size ~10 nm have been coated with silica SiO2 and Thioflavin-T (ThT), a non-toxic fluorescent dye binding to the amyloid- structures with a possible effect on fibril formation, and then added to phosphate-buffered saline solution, incubated for 30 min and extracted by magnetic separation. The magnetic ThT silica-coated nanoparticles with size ~20 nm have been characterized structurally and magnetically by powder X-ray powder diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, and vibrating sample magnetometer. Their affinity to peptide, examined by fluorescence microscopy and protein concentration measurements using the BCA Protein Assay Kit has been verified. Successful binding of magnetic silica nanoparticles, doped with ThT, to peptide provides a nanocarrier potentially exemplifying multiple functions, such as magnetic imaging, magnetic handling, drug delivery, fluorescence imaging, $text{A}beta $ binding, and aggregation inhibition.
Autors: Apostolos C. Tsolakis;Eleftherios Halevas;Nikolaos Vouroutzis;George G. Koliakos;Athanasios Salifoglou;George Litsardakis;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Flux Analysis of a New Field-Excitation Flux Switching Motor Using Segmental Rotor
Abstract:
Recently, a three-phase field-excitation flux switching motor (FEFSM) with salient rotor structure has been introduced with their advantages of easy rotor temperature removal and controllable field excitation coil (FEC) magnetic flux particularly suitable for high torque, high power, and high-speed diverse performances. Nevertheless, the salient rotor structure is found to lead a longer magnetic flux path between stator and rotor producing weak flux linkage along with low torque performances. Besides, the overlap armature coil and FEC windings yield high coil end length, producing much high copper loss and large motor size. In this paper, a new FEFSM using segmental rotor with non-overlap armature coil and FEC windings is proposed. The shorter magnetic flux path of the proposed segmental rotor is noticeably more focused to produce much higher torque while the non-overlap armature and FEC will reduce the copper loss and motor weight. Both FEFSMs with salient and segmental rotors are designed using 2-D-FEA JMAG Designer version 14.1 for comparison. As a result, magnetic flux of the segmental rotor design is 11 times higher than the salient rotor structure mainly due to shorter magnetic flux linkage between two stator teeth and single rotor segment. The torque and power of 0.91 Nm and 293 W, respectively, are obtained from the new FEFSM which are much higher than salient rotor design. In addition, the simulation and experimental results show a good agreement in back-electromotive force amplitude and waveform at various speeds, as well as similar increment of torque versus FEC current characteristics. As the conclusion, the proposed FEFSM with non-overlap and segmental rotor structure has produced much higher flux, with significant improvement of torque and power performances compared with existing FEFSM with salient rotor.
Autors: M. F. Omar;E. Sulaiman;M. Jenal;R. Kumar;R. N. Firdaus;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Loss Versus Frequency in Non-Oriented Steel Sheets and Its Prediction: Minor Loops, PWM, and the Limits of the Analytical Approach
Abstract:
The pulsewidth modulation (PWM) technique is commonly used to supply modern high-speed electrical machines. The fundamental frequency is typically in the kilohertz range, with switching frequencies of several tens of kilohertz, as determined by the new SiC- or GaAs-based power transistors modules. Switching introduces minor loops in the major hysteresis cycle, with durations of the order of or lower, with the resulting magnetization dynamics influenced by strong skin effect. However, since these minor loops have relatively small amplitude, their constitutive equation may be described by an equivalent permeability (real or complex), depending on the mean slope of the minor loop and its static energy loss. By retrieving this permeability, the classical loss is straightforwardly calculated by analytical solution of Maxwell's equations. In this paper, we measure and calculate, according to the quasi-linear approximation for the minor loops, the magnetic energy losses of 0.194 mm thick non-oriented Fe–Si 3.2% sheets subjected to PWM induction waveform. Minor loop peak amplitudes ranging between 50 mT and 0.2 T and frequencies up to 10 kHz are investigated. The results are consistent with the proposed model, to within 5%.
Autors: Hanyu Zhao;Carlo Ragusa;Olivier de la Barrière;Mahmood Khan;Carlo Appino;Fausto Fiorillo;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Materials Used in Electrical Machines: A Comparison and Selection Guide for Early Machine Design
Abstract:
This article presents an up-to-date magnetic material investigation and overview on soft magnetic materials used in rotating electrical machines. The focus is on small-to-medium-sized high-performance and high-efficiency permanent-magnet and induction motors for different application scenarios. The investigated materials include fully processed silicon-iron (SiFe), nickel-iron (NiFe), and cobalt-iron (CoFe) lamination steels as well as soft magnetic composites (SMCs) and amorphous magnetic materials. This article focuses on the magnetic properties and iron losses as well as the manufacturing influence and required thermal treatments during the manufacturing process. A new loss-to-flux-density factor is introduced to compare the magnetization curve and the iron losses of different materials within the same diagram. This article provides a review and comparison of magnetic substances for use in high-performance machines.
Autors: Andreas Krings;Marco Cossale;Alberto Tenconi;Juliette Soulard;Andrea Cavagnino;Aldo Boglietti;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 21 - 28
Publisher: IEEE
 
» Magnetic Modeling of a Linear Synchronous Machine With the Spectral Element Method
Abstract:
The field calculus for electrical machines (EMs) is realized solving subdomain problems. Most often, the latter are solved using either finite element analysis (FEA) or the semi-analytical solution of a Laplace or Poisson equation obtained by separation of variables. The first option can capture complex geometries but becomes slow for high accuracy, whereas the second is fast but limited to simple periodic geometries and linear or infinite permeable materials. This paper presents the 2-D implementation of the spectral element method (SEM) for the modeling of EMs. The polynomial basis functions used to approximate the solution in each domain are reaching exponential convergence similar to the semi-analytical solution. Moreover, each element can be represented by a non-square shape resulting in the possibility to model complex geometries. Following the results in this paper, significantly fewer degrees of freedom are needed for the SEM to achieve the approximation similar to the FEA, and consequently less memory and computational time are required.
Autors: M. Curti;J. J. H. Paulides;E. A. Lomonova;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Magnetic Noise and Spin-Wave Eigenmodes in a Magnetic Tunnel Junction Read Head
Abstract:
With read-head structures becoming very small (<30 nm typical size), thermal fluctuations of the free and reference layers, occurring in the gigahertz range of frequencies, may become relatively large (>20°) and cause the appearance of considerable magnetic noise in the read-back function. For instance, the experimental test of a read-head sensor shows that a considerable low-frequency noise appears in the measured signal in coincidence with the superposition of high-frequency eigenmodes of the stack. To shed light on these experimental data, we perform extensive micromagnetic simulations to analyze the spin-wave spectrum of the read-head sensor and its evolution under the application of an external magnetic field. We show that the nonuniformity of both the bias field and the demagnetizing field induces pronounced spatially dependent dynamics within each layer. Moreover, the derived read-back function is characterized by different peaks that reflect the underlying eigenmodes spectrum, as suggested also by simple macrospin approach. However, for large precession amplitude, nonlinear and mixing effects appear, leading to the presence of extra peaks and of a low-frequency tail in the readback signal, in qualitative agreement with experiments.
Autors: M. Pauselli;A. Stankiewicz;Y. Zhang;G. Carlotti;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Magnetic Orientational Properties of Monosodium Urate Crystals
Abstract:
Monosodium urate (MSU) crystals are the cause of gout and are formed from uric acid and sodium. Because they can be rotated by the torque induced by an applied magnetic field, we have characterized their detailed magnetic orientational properties to improve the detection sensitivity from outside the body using the magnetic orientation. The MSU crystals were precipitated by dissolving uric acid powder in aqueous sodium hydroxide. In serum, the MSU crystals were small and uniformly sized, similar to those obtained from gout patients. The MSU crystals were not completely oriented perpendicular to the magnetic-field direction, but rather the c-axis of the crystal was inclined with respect to the field direction. Specifically, they were inclined at a mean of 69.3° under a magnetic field of 500 mT. The MSU crystals were not perfectly oriented in magnetic fields <200 mT. The inclination results from the molecular structure of the MSU crystal.
Autors: Y. Takeuchi;M. Sekiya;A. Hamasaki;M. Iwasaka;M. Matsuda;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Particle Spectrometry of Fe3O4 Multi-Granule Nanoclusters
Abstract:
Magnetic particle imaging (MPI) is a novel high-resolution medical imaging method that does not use ionizing radiation, but safe iron oxide nanoparticles as contrast agents. By employing magnetite (Fe3O4) multi-granule nanoclusters (MGNCs), one has two control parameters: the diameter of the particles and that of granules in single particles. Here we investigate the effect of the size of the particles at constant granule size, as well as the effect of granule size at constant particle size on the magnetization reversal. The saturation magnetization Ms value increases with increasing granule diameter and particle diameter, while the coercivity Hc value reaches a maximum at a particle size of about 60 nm. MGNCs with an average particle size of 77 nm and granule diameter of 17 nm show a larger response in the higher harmonics compared to the commercial reference, FeraSpin R dispersion, at both 20 and 30 mT. This result demonstrates that the MGNC concept allows tailoring of the magnetic properties of the particles to the imaging conditions in MPI.
Autors: Lijun Pan;Bum Chul Park;Micheal Ledwig;Leon Abelmann;Young Keun Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Properties and Columnar Structure for CoPt Alloy Granular Media With Grain Boundary Oxides of Various Melting Points
Abstract:
Investigation of the effect of the melting point ( of various single oxides on the columnar growth and generation of the nucleation site for CoPt granular media deposited at room temperature were conducted. When oxide with from 1857 °C to 2410 °C is added to the granular media, thickness of the heteroepitaxial growth of the magnetic grains on the Ru underlayer (columnar structure) decreases from 13 to 5.5 nm. The employment of oxide with of the range from 450 °C to 2410 °C to the granular media will lead to the reduction of grain size from 5.6 to 3.0 nm, due to the suppression of the lateral grain growth by the high oxide.
Autors: Ryosuke Kushibiki;Kim Kong Tham;Shintaro Hinata;Shin Saito;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Properties and Microstructure of FePt Films With MgTiON Intermediate Layer
Abstract:
The magnetic properties and microstructure of FePt films grown on MgTiON intermediate layer were studied. The MgTiON layer was deposited by sputtered (MgTi)ON target at 395 °C. The MgTiON (002) texture was formed on CrRu (002)/glass. Furthermore, the 10 nm thick FePt film was deposited on MgTiON at 450 °C. The FePt shows perpendicular magnetization with out-of-plane coercivity of 3.62 kOe. Smaller FePt out-of-plane coercivity may come from lower ordering degree and continuous layer structure, which provides easy domain wall motion. To promote the ordering of FePt film, thinner MoC layer with thickness of 1 to 3 nm was capped on MgTiON (30 nm) layer during sputtering process. The FePt films with thickness from 4 to 10 nm show perpendicular magnetic anisotropy and the out-of-plane coercivities were increased to 11.9–15.3 kOe. The significant change of FePt out-of-plane coercivity was explained by ordering degree and microstructure. The island growth was dominated when FePt film prepared on thinner MoC interface and the excess carbon from MoC layer was diffused up to promote the ordering of FePt during sputtering. As a result, higher FePt out-of-plane coercivity on MoC/MgTiON intermediate layer was due to higher ordering degree and domain wall pinning effect in separated FePt islands.
Autors: Jai Lin Tsai;Hsu Kang Li;Zu Yu Pan;Yuan Shuo Chang;Yu Ren Chen;Chen Pi;Yu Ting Wu;Ching Wei Chang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Properties of L10 FeNi Phase Developed Through Annealing of an Amorphous Alloy
Abstract:
Chemically ordered L10 FeNi phase observed in Fe-based meteorite has the potential to replace high-cost rare-earth-based permanent magnets in the future. However, artificial production of this phase is extremely difficult due to negligible atomic diffusion around order–disorder transition temperature (~320 °C). Here, we report a method for producing high-quality L10 FeNi phase and its magnetic properties. We show that a highly disordered metastable state, that is, amorphous can be utilized to produce a highly ordered state, which is not possible with the conventional processing techniques. Amorphous Fe42Ni41.3SixB12−xP4Cu0.7 ( to 8 at.%) alloy ribbons were studied. Crystallization of amorphous ribbons at 400 °C results in adequate atomic diffusion at low temperatures to precipitate L10 FeNi grains. Structural characterization revealed a high degree of chemical ordering (), but the volume fraction of precipitated L10 grains is low. The crystallized ribbons of FeSiBPCu are composed of two magnetic phases (hard magnetic L10 FeNi grains embedded in a soft magnetic matrix). Alloys with higher concentration of Si are shown to produce high coercivity (–750 Oe). The soft magnetic matrix strongly influences the Hc. The actual switching field (≥3.7 kOe) of L10 FeNi has been found to be much higher than that of Hc. In this paper, the L10 FeNi phase is s- own to form at temperatures higher than the reported order–disorder temperature. Our results of temperature-dependent magnetization and thermal analyses suggest that the L10 FeNi phase can survive at temperatures ≤550 °C. The magnetization reversal mechanism was understood by angular dependence of , and it is shown to be a domain-wall pinning type. Due to structural and magnetic similarities between L10 FeNi and L10 FePt, ribbon samples with low-volume fraction of L10 FePt grains in a soft magnetic matrix were prepared with a similar technique. Magnetization behavior of L10 FeNi is shown to be similar to that of L10 FePt.
Autors: Parmanand Sharma;Yan Zhang;Akihiro Makino;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 10
Publisher: IEEE
 
» Magnetic Properties of Nanocrystalline N-NFO Thin Films
Abstract:
The pure as well as nitrogen incorporated nickel ferrite (NFO and N-NFO) thin films were grown by radio frequency magnetron sputtering technique. The structural investigations of as-grown N-NFO films using GIXRD and Raman spectroscopy revealed nanocrystalline nature of the films. The microstructural and surface studies of the films using SEM and atomic force microscope micrographs showed increase in crystallite size and decrease in surface roughness with increase of sputtering power. The magnetization (M-H) measurements at 20 and 300 K revealed an increase in magnetization and decrease in coercivity values with increase of sputtering power. However, no saturation of magnetization () was visible for the thin film samples, indicating superparamagnetic behavior due to nanocrystallinity. The comparison of in-plane and out-of-plane magnetizations of the N-NFO film (both at 20 and 300 K) showed that the easy magnetization direction lied in the plane of the film. The optical transmission spectra revealed decrease of direct band gap with increase of sputtering power.
Autors: K. B. Anoop Baby;G. Markandeyulu;A. Subrahmanyam;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Magnetic Properties of Pure Iron Soft Magnetic Composites Coated by Manganese Phosphates
Abstract:
Soft magnetic composites using metallic magnetic powders have extensively been investigated for the application to mobile electromagnetic devices, particularly motor cores. These metal powders are strongly required to be insulated from one another for low eddy-current losses. In addition, the insulation layer of the powders should possess high thermal stability for low hysteresis losses. Despite poor thermal stability, the iron phosphate coating on iron powders is still widely used because of a well-established technology. In this paper, we focused on the development of manganese phosphate coating on iron powders to overcome the low thermal stability of iron phosphate. It was shown that manganese phosphate insulation layers were thermally stable up to 600 °C. The core loss of composites with manganese phosphate-coated powders annealed at 600 °C measured 35.67 W/kg and the eddy-current loss 5.65 W/kg, indicating that excellent insulation coating layers were formed.
Autors: Sounghun Lee;Moosung Choi;Jongryoul Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Property Enhancement of Melt Spun YCo5 Ribbons by Fe and C Doping
Abstract:
Magnetic properties and microstructure of melt spun YCo5–xyFexCy (–0.3 and –0.3) ribbons are studied. Magnetic properties of YCo5 ribbons (iHc = 144 kA/m and (BH) kJ/m3 are slightly improved to iHc = 160–224 kA/m and (BH)–27.2 kJ/m3 by Fe-doping, and are increased to iHc = 560–1128 kA/m and (BH)–51.2 kJ/m3 by C-doping, respectively. Most interestingly, the optimal (BH) of 72.8 kJ/m3 with high iHc of 1200 kA/m achieved for Fe and C-co-doped YCo4.6Fe0.3C0.3 ribbons is the highest value in Y–Co alloy ribbons ever reported. The structural and thermo-magnetic analysis confirm that Fe and C enter the YCo5 (5:1) crystal structure and lead to the increase of Curie temperature. Besides, C-doping uniformly refines grain size and, therefore, improves the squareness of demagnetization curve and (BH). The formation of YCo, Fe)5Cx phase and the microstructure refinement are the main reasons to result in the enhancement of hard magnetic properties for the YCo4.4Fe0.3C0.3 ribbons. The presented results suggest that the YCo5 ribbons optimized by co-doping with Fe and C are promising candidate materials for making bonded magnets.
Autors: H. W. Chang;W. C. Ou;Y. I. Lee;C. W. Shih;W. C. Chang;C. C. Yang;C. C. Shaw;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Reader Instability as a Source of Low-Frequency Noise
Abstract:
Detecting and characterizing magnetic stability is one of the main goals in hard drive reader testing. A simple model of a bi-stable system leads to random telegraph noise, and reveals spectral characteristics of unstable readers, which may be used for instability detection in standard reader testing. In particular, it proves that unstable devices may show noise reduction with temperature increase, which has been confirmed experimentally. Furthermore, characterization of the telegraph noise in magnetic readers is achieved by high bandwidth time-domain measurements, followed by waveform analysis based on a hidden Markov model. An example of actual reader analysis leads to the estimation of activation energy.
Autors: Andrzej Stankiewicz;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetic Subsurface Imaging Systems in a Smartphone Based on the Built-In Magnetometer
Abstract:
We present a magnetic subsurface imaging system on a smart-phone that employs the built-in magnetometer. The smart-phone’s sensor measures magnetic field strength at sparse locations on a user-defined grid of the surveyed area. Based on the collected data, magnetic field distribution of the entire area is then reconstructed by using an interpolation algorithm, which yields field values in all of three-axial directions. Since the field shows the influence of the buried objects within the surveyed area to the background magnetic fields, the shape and size of the objects can be derived from the image representing the field. An implementation of the system as an application software on Android smart-phone, which consists of data measurement and reconstruction subsystems, is also described. We demonstrate the capability of the proposed system by performing subsurface imaging of small hidden objects in a laboratory test-range.
Autors: Andriyan B. Suksmono;Donny Danudirdjo;Antonius D. Setiawan;Dien Rahmawati;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Magnetoconductivity of the La1–xSrxMnO3@TiO2 Nanocomposite
Abstract:
The study deals with tunneling magnetoresistance in a composite system of so-called 0-3 connectivity, in which ferromagnetic metallic nanoparticles La1–xSrxMnO3 (0-dim objects) are embedded in the (3-dim) insulating matrix of TiO2. The sample fabrication included the sol-gel preparation of manganite particles of the x = 0.35 composition and 25 nm mean crystallite size, their coating by TiO2, and compacting the products by spark plasma sintering. A comparative nanogranular sample was prepared by spark plasma sintering of bare manganite particles. The resistivities of the composite and comparative sample are 100,000 and 100 times higher compared to bulk metallic La1–xSrxMnO3. Otherwise, the temperature dependence observed in the nanogranular La1–xSrxMnO3 sample is similar to single crystal data, and marked localization is absent also in the La1–xSrxMnO3@TiO2 nanocomposite. The data taken in applied fields up to 4 Tesla reveal effects typical for grain-boundary tunneling in manganites, namely the coexistence of the low-field magnetoconductance (LFMC), reflecting the field-induced alignment of FM cores, and high-field linear magnetoconductance (HFMR) that is generally ascribed to the effect of spin canting at localized Mn4+ sites in the interface. This is considered as a signature for resonant tunneling of spin-polarized carriers, theoretically treated by S. Lee et al. [1]. The present results show that the total extent of LFMC makes 45% in the La1–xSrxMnO3@TiO2 nanocomposite and 21% in the La1–xSrxMnO3 nanogranular sample. The slope of HFMC has been determined to 5.4% and 4.9% per Tesla, respectively. The large LFMC effect observed in the nanocomposite exceeds the theo- etical prediction of 33% for the second-order tunneling, which might suggest for higher-order tunneling via resonant states.
Autors: Jakub Koktan;Graziella Goglio;Jiří Hejtmánek;Zdeněk Jirák;Karel Knížek;Jarmila Kuličková;Miroslav Maryško;Ondřej Kaman;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Magnetoelastic Properties of Epitaxially Grown Co2Fe0.4Mn0.6Si and Co2FeGa0.5Ge0.5 Heusler Alloys Thin Films
Abstract:
The out-of-plane magnetocrystalline anisotropy and magnetoelastic properties of series of epitaxially grown layers of Co2Fe0.4Mn0.6Si (CFMS) and Co2FeGa0.5Ge0.5 (CFGG) Heusler alloys thin films deposited on MgO with chromium buffer layer were investigated by means of the ferromagnetic resonance (FMR), SQUID magnetometer, and by the strain modulated FMR technique. The magnitude of the magnetocrystalline anisotropy constant was found to decrease with increasing layer thickness. The change of the anisotropy is caused mainly by the surface effects. However, for some of the samples series, the change of chemical ordering with the change of the magnetic layer thickness was also observed. An additional silver buffer layer influence on the properties of the magnetic layer was also investigated. For all three of the investigated series of the Heusler alloys, i.e., CFMS without Ag, CFMS with Ag, and CFGG, the experimentally observed magnitude of the magnetoelastic constant increases with the increase of the magnetic layer thickness.
Autors: O. M. Chumak;A. Nabiałek;R. Zuberek;I. Radelytskyi;T. Yamamoto;T. Seki;K. Takanashi;L. T. Baczewski;H. Szymczak;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Magnetoimpedance in Samples With Patterned Surfaces for the Detection of Magnetic Particles and Ferrofluids
Abstract:
Magnetoimpedance (MI) has been proposed as a sensible detection method for quantifying the concentration of magnetic microparticle and nanoparticle. The use of samples with severe surface roughness, induced by acid treatments, seems to enhance the detection power. Here, we clarify the role of surface modification in the detection of magnetic particles and ferrofluids. Experimentally, lithography is used to produce a regular pattern of pits in an amorphous ribbon. The influence of the patterning on the MI of the sample, in the presence of magnetic nanoparticles, is analyzed. Contrary to what has been published previously, the patterning seems to worsen the particle detection capability. To clarify the situation, a thorough study is performed with numerical simulations using a finite-element analysis resembling the experimental conditions in a 2-D geometry. The presence of magnetic particles is simulated as a continuum medium with a given permeability, which is a realistic assumption for the case for ferrofluids. The conclusion is that the effect of the magnetic particles on MI depends strongly on the characteristics of the patterning and on the concentration of particles. The simulation results not only qualitatively explain ours experimental results, but also help interpreting previous reports and hints the optimal conditions for the surface patterning in order to maximize the sensibility of the sample to the presence of magnetic particles.
Autors: Alfredo García-Arribas;Maite Goiriena-Goikoetxea;Eduardo Fernández;José Manuel Barandiarán;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Magnetorheology of Snowman-Like Anisotropic Microparticle Added Carbonyl Iron Suspension
Abstract:
The improvement of the magnetorheological (MR) performance of a carbonyl iron (CI)-based MR fluid was assessed by adding nonmagnetic anisotropic snowman-like polymethyl methacrylate (PMMA) particles as an additive. The snowman-like PMMA particles were synthesized by a seed emulsion polymerization method. The rheological properties of the MR fluids with and without the additives were examined by using a rotational rheometer under various applied magnetic-field strengths. Enhanced rheological properties and improved sedimentation stability of the CI/snowman-like PMMA-based MR fluid were observed compared to those of the pure CI-based MR fluid.
Autors: Ha Young Kim;Seung Hyuk Kwon;Hyoung Jin Choi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetostriction Behaviors of Ni100−xFex and Ni100−yCoy (001) Single-Crystal Films with fcc Structure under Rotating Magnetic Fields
Abstract:
Ni100–xFex (x = 0, 20 at. %) and Ni100–yCoy (y = 0, 25, 50, 75, 100 at. %) alloy single-crystal films of fcc(001) orientation are prepared through hetero-epitaxial growth on Cu(001) single-crystal underlayers at 300 °C. The effects of Fe/Ni and Co/Ni compositions on the magnetic anisotropy and the magnetostriction behavior under rotating magnetic fields are investigated. The Ni single-crystal film shows a nearly isotropic in-plane magnetic property. The Ni80Fe20 and the Ni100–yCoy (y = 25–100) single-crystal films show four-fold symmetries in in-plane magnetic anisotropy. The easy magnetization direction is observed along [110] and [11 _ 0] for the Ni80Fe20 and the Ni100–yCoy (y = 50–100) films, whereas that is recognized along [100] and [010] for the Ni75Co25 film. The easy magnetization axis varies depending on the Co/Ni composition. The in-plane magnetic anisotropy increases with increasing the Co content. Triangular output waveforms of magnetostriction appear when the Ni80Fe20 and the Ni100–yCoy (y = 25–100) films are measured under low rotating magnetic fields. The magnetostriction behavior is related with the magnetization direction in a magnetically unsaturated film with inplane magnetic anisotropy. As the rotating magnetic field increases, the magnetization approaches saturation and the waveform gradually changes to a usual sinusoidal shape. As the in-plane anisotropy increases, a higher rotating field is required to obtain a sinusoidal waveform. On the contrary, sinusoidal waveforms are observed for the Ni film, even when the magnetization is not saturated. The waveform of magnetostriction is affected by the symmetry and the strength of in-plane magnetic anisotropy.
Autors: Kana Serizawa;Tetsuroh Kawai;Mitsuru Ohtake;Masaaki Futamoto;Fumiyoshi Kirino;Nobuyuki Inaba;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetotransport in Ultrathin 2-D Superconducting Mo2C Crystals
Abstract:
Ultrathin transition metal carbides are a class of emerging 2-D materials with many intriguing properties and applications. Here, we report the transport measurements on high-quality ultrathin Mo2C crystals, which are synthesized by a chemical vapor deposition method. We demonstrate 2-D nature of the observed superconductivity in ultrathin Mo2C crystals, being consistent with a Berezinskii–Kosterlitz–Thouless transition. As the sample thickness decreases, the Mo2C crystals exhibit negative magnetoresistance behavior at low magnetic fields deep in the superconducting state. We attribute these results to strong phase fluctuations of the superconducting order parameters near the superconductor–insulator transition. Our results demonstrate that these high-quality ultrathin Mo2C crystals provide an appealing platform to gain insights into 2-D superconductivity in a clean system.
Autors: Shuang Song;Libin Wang;Chuan Xu;Hui-Ming Cheng;Wencai Ren;Ning Kang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Magnetron Coupling to Sulfur Plasma Bulb
Abstract:
Sulfur plasma lamps are a convenient, table-top system for the study of acoustics in dense, weakly ionized plasmas. Herein, we describe the construction and tuning of a passive waveguide circuit capable of igniting and sustaining the sulfur plasma and exciting acoustic modes within it.
Autors: John P. Koulakis;Alexander L. F. Thornton;Seth Putterman;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Nov 2017, volume: 45, issue:11, pages: 2940 - 2944
Publisher: IEEE
 
» Maintaining Balance: The Increasing Role of Energy Storage for Renewable Integration
Abstract:
For nearly a century, global power systems have focused on three key functions: generating, transmitting, and distributing electricity as a real-time commodity. Physics requires that electricity generation always be in real-time balance with load-despite variability in load on time scales ranging from subsecond disturbances to multiyear trends. With the increasing role of variable generation from wind and solar, the retirement of fossil-fuel-based generation, and a changing consumer demand profile, grid operators are using new methods to maintain this balance.
Autors: Derek Stenclik;Paul Denholm;Babu Chalamala;
Appeared in: IEEE Power and Energy Magazine
Publication date: Nov 2017, volume: 15, issue:6, pages: 31 - 39
Publisher: IEEE
 
» Making a Difference [From the Editor's Desk]
Abstract:
Presents the introductory editorial for this issue of the publication.
Autors: Lanny Floyd;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 4 - 5
Publisher: IEEE
 
» Making Sense of the Ransomware Mess (and Planning a Sensible Path Forward)
Abstract:
It started out as a seemingly isolated event. Reports early during the morning of 12 May 2017 talked about an unknown piece of ransomware attacking systems within the British National Health System (NHS) hospital network. Well over 50,000 NHS systems were infected, forcing affected hospitals to divert pat ients to other facilities. As hours passed, however, it became clear that this event was not isolated, and systems spanning more than 150 countries quickly succumbed to what would come to be known as WannaCry (which is known by multiple names including WanaCry, WannaCrypt, and WannaCrypt0r, among others.)
Autors: Nolen Scaife;Patrick Traynor;Kevin Butler;
Appeared in: IEEE Potentials
Publication date: Nov 2017, volume: 36, issue:6, pages: 28 - 31
Publisher: IEEE
 
» Making the Leap to Electric Motors and Adjustable-Speed Drives: A Case Study of a 20,000-hp Gas Turbine-Driven Compressor
Abstract:
Compressors of all forms, types, and sizes are the workhorses of the oil and gas industry. Historically, the petrochemical industry has been dominated by mechanical prime movers, such as gas turbines, steam turbines, and diesel engines for multimegawatt rotating machinery. Some installations date back almost 40-50 years. In recent times, the prime movers have become difficult and expensive to service and maintain. They often have lower efficiencies than new equipment, and spare parts can be difficult to find. When U.S. Environmental Protection Agency (EPA) permits expire, and because strict emission compliance is mandatory, many end users face the challenging task of decommissioning their entire compressor train and procuring a new one. However, a workable and cost-effective solution is to retrofit existing mechanical-based prime movers while retaining the functioning gas compressor.
Autors: Manish Verma;Derrick Parker;Izhak Ike Grinbaum;James Nanney;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 29 - 38
Publisher: IEEE
 
» MALM: Mobility-Aware Location Management Scheme in Femto/Macrocell Networks
Abstract:
Recently, femtocells are widely deployed to offload the traffic from the macrocell. Since conventional location management schemes of femto/macrocell networks do not consider mobility pattern of the mobile node (MN), unnecessary location updates can occur. Specifically, when an MN moves along the contour of the femtocell coverage, the MN frequently executes location update procedures, which causes significant location update cost. To address this problem, we propose a mobility-aware location management (MALM) scheme, where the MN conducts location update only at specific femtocells in which it is expected that the MN stays for a long time. To optimize MALM, a Markov decision process (MDP) problem is formulated and the optimal policy is determined. Evaluation results demonstrate that MALM with the optimal policy can reduce the number of location updates while providing sufficient offloading gain.
Autors: Haneul Ko;Jaewook Lee;Sangheon Pack;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3115 - 3125
Publisher: IEEE
 
» MAMR Frequency Selection on [CoX/Pt]4 Media
Abstract:
In microwave-assisted magnetic recording (MAMR), the frequency selection of the assisted microwave magnetic field is important. In this paper, we set up a micromagnetic model of [CoX/Pt]4 media with a different anisotropy configuration to study the frequency selection based on media signal-to-noise ratio (SNR) by the simulation of writing performance. By evaluating each layer’s SNR, we find that the four-layer integrated SNR- relationship is more influenced by the top two layers, and the interlayer exchange coupling strength plays a dominant role on the consistent SNR- curve in each media layer. When Hiec = 2000 Oe, the optimum frequency in each layer is coherent; when Hiec = 1000 Oe, the optimum frequency has a 2 GHz difference in four layers. When the average anisotropy field is in a range of 19–25 kOe, the integrated optimum frequency with highest media SNR increases versus with a slope of 1.87 GHz/kOe, smaller than the ferromagnetic resonant frequency coefficient of around 3 GHz/kOe, which is beneficial for MAMR applications. With optimized intergrain exchange strength and optimum frequency GHz, an areal writing density limit of 3 Tbit/in2 can be achieved.
Autors: Zhen Zhao;Dan Wei;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Manufacturing of Die-Upset Rare Earth–Iron–Boron Magnets With (Ce,La)-Mischmetal
Abstract:
Utilization of the relatively abundant and inexpensive (Ce,La)-mischmetal in manufacturing die-upset R–Fe–B magnets (R = rare earth) from melt-spun nanocrystalline alloys was attempted via: 1) the standard single-alloy process; 2) the diffusion of Nd and Pr from low-melting-temperature alloys blended into the magnet; and 3) the diffusion of Nd and Pr by infiltrating the magnet through its surface. No practically viable magnetic properties could be obtained without the introduction of Nd(Pr). Blending with the (Nd,Pr)-rich alloys was found to be less efficient for the development of coercivity than the single-alloy process; so was the infiltration of those precursors which had been alloyed with 0.5 at.% Ga. More efficient than the single-alloy process was infiltration of those precursors which had been alloyed with 2 at.% Si or with 1 at.% Zn. Coercivities of 7–10 kOe and energy products of 17–20 MGOe were obtained for magnets having 43%–55% of the R elements represented by Ce0.65La0.35 and containing overall 7.5–9.7 at.% Nd(Pr). The coercivity of the significantly hyper-stoichiometric (17–19 at.% R) (Ce,La)-containing alloys was found to decline 80% or more as a result of the deformation process, but partially recover after subsequent annealing. The latter improvement is likely to be caused by redistribution of the R-rich phases.
Autors: Alexander M. Gabay;George C. Hadjipanayis;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Maritime Traffic Probabilistic Forecasting Based on Vessels’ Waterway Patterns and Motion Behaviors
Abstract:
Maritime traffic prediction is critical for ocean transportation safety management. In this paper, we propose a novel knowledge assisted methodology for maritime traffic forecasting based on a vessel’s waterway pattern and motion behavior. The vessel’s waterway pattern is extracted through a proposed lattice-based DBSCAN algorithm that significantly reduces the problem scale, and its motion behavior is quantitatively modeled for the first time using kernel density estimation. The proposed methodology facilitates the knowledge extraction, storage, and retrieval, allowing for seamless knowledge transfer to support maritime traffic forecasting. By incorporating both the vessel’s waterway pattern and motion behavior knowledge, our solution suggests a set of probable coordinates with the corresponding probability as the forecasting output. The proposed forecasting algorithm is capable of accurately predicting maritime traffic 5, 30, and 60 min ahead, while its computation can be efficiently completed in milliseconds for single vessel prediction. Owing to such a high computational efficiency, an extensive predictive analysis of hundreds of vessels has been reported for the first time in this paper. A web-based prototype platform is implemented for Singapore waters to demonstrate the solution’s feasibility in a real-world maritime operation system. The proposed approaches can be generalized for other marine waters around the world.
Autors: Zhe Xiao;Loganathan Ponnambalam;Xiuju Fu;Wanbing Zhang;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3122 - 3134
Publisher: IEEE
 
» MARTA GANs: Unsupervised Representation Learning for Remote Sensing Image Classification
Abstract:
With the development of deep learning, supervised learning has frequently been adopted to classify remotely sensed images using convolutional networks. However, due to the limited amount of labeled data available, supervised learning is often difficult to carry out. Therefore, we proposed an unsupervised model called multiple-layer feature-matching generative adversarial networks (MARTA GANs) to learn a representation using only unlabeled data. MARTA GANs consists of both a generative model and a discriminative model . We treat as a feature extractor. To fit the complex properties of remote sensing data, we use a fusion layer to merge the mid-level and global features. can produce numerous images that are similar to the training data; therefore, can learn better representations of remotely sensed images using the training data provided by . The classification results on two widely used remote sensing image databases show that the proposed method significantly improves the classification performance compared with other state-of-the-art methods.
Autors: Daoyu Lin;Kun Fu;Yang Wang;Guangluan Xu;Xian Sun;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2092 - 2096
Publisher: IEEE
 
» Massive MIMO With Max-Min Power Control in Line-of-Sight Propagation Environment
Abstract:
Massive MIMO relies on the asymptotic orthogonality of channel vectors to different users. For service antennas, the expected correlation between a pair of channel vectors under line-of-sight (LoS) conditions decreases at least as fast as , while in independent and identically distributed (iid) Rayleigh fading, it decreases much slower at , but the variance is higher under LoS. This signifies that typically channel vectors are more nearly orthogonal under LoS, but with a non-negligible probability, they can have an anomalously large correlation. A single-cell analysis discloses that Massive MIMO with max-min power control performs comparably under LoS and iid Rayleigh, when a simple algorithm is applied under LoS to drop a small number of high-correlation users from service.
Autors: Hong Yang;Thomas L. Marzetta;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4685 - 4693
Publisher: IEEE
 
» Massive MIMO-Enabled Full-Duplex Cellular Networks
Abstract:
We provide a theoretical framework for the study of massive multiple-input multiple-output (MIMO)-enabled full-duplex (FD) cellular networks in which the residual self-interference (SI) channels follow the Rician distribution and other channels are Rayleigh distributed. In order to facilitate bi-directional wireless functionality, we adopt: 1) in the downlink (DL), a linear zero-forcing (ZF) with SI-nulling precoding scheme at the FD base stations and 2) in the uplink (UL), an SI-aware fractional power control mechanism at the FD mobile terminals. Linear ZF receivers are further utilized for signal detection in the UL. The results indicate that the UL rate bottleneck in the FD baseline single-input single-output system can be overcome via exploiting massive MIMO. On the other hand, the findings may be viewed as a reality-check, since we show that, under state-of-the-art system parameters, the spectral efficiency gain of FD massive MIMO over its half-duplex counterpart is largely limited by the cross-mode interference between the DL and the UL. In point of fact, the anticipated twofold increase in SE is shown to be only achievable when the number of antennas tends to be infinitely large.
Autors: Arman Shojaeifard;Kai-Kit Wong;Marco Di Renzo;Gan Zheng;Khairi Ashour Hamdi;Jie Tang;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4734 - 4750
Publisher: IEEE
 
» Massive Multiuser MIMO in Heterogeneous Cellular Networks With Full Duplex Small Cells
Abstract:
Full duplex (FD) communication has emerged as an attractive solution for increasing the network throughput, by allowing downlink (DL) and uplink (UL) transmissions in the same spectrum. However, only employing FD base stations in heterogeneous cellular networks (HCNs) cause coverage reduction, due to the DL and UL interferences as well as the residual loop interference. We, therefore, propose HCNs with half duplex massive multiuser multiple-input multiple-output macrocell base stations (MBSs) to relax the coverage reduction, and FD small cell base stations (SBSs) to improve spectrum efficiency. A tractable framework of the proposed system is presented, which allows to derive exact and asymptotic expressions for the DL and the UL rate coverage probabilities, and the DL and the UL area spectral efficiencies (ASEs). Monte Carlo simulations confirm the accuracy of the analytical results, and it is revealed that the equipping massive number of antennas at MBSs enhances the DL rate coverage probability, whereas increasing FD SBSs increases the DL and the UL ASEs. The results also demonstrate that by tuning the UL fractional power control, a desirable performance in both UL and DL can be achieved.
Autors: Sunila Akbar;Yansha Deng;Arumugam Nallanathan;Maged Elkashlan;George K. Karagiannidis;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4704 - 4719
Publisher: IEEE
 
» Max–Min Fair Resource Allocation for SWIPT in Multi-Group Multicast OFDM Systems
Abstract:
Simultaneous wireless information and power transfer is considered for multi-group multicasting OFDM systems. Each user has the energy harvesting capability through a power splitter (PS). The power and subcarrier allocation at the base station is done such that the minimum signal-to-noise ratio among the users for each subcarrier is maximized while user needs for harvested power are satisfied. The optimization of PS ratios in addition to resource allocation is realized in a joint manner. It is shown that the problem can be cast in a convex optimization form for the given subcarrier sets. In order to determine the subcarrier sets, an efficient subcarrier allocation algorithm is proposed. It is shown that the proposed method performs very close to the exhaustive search, which gives the optimum solution.
Autors: Özlem Tuğfe Demir;Temel Engin Tuncer;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2508 - 2511
Publisher: IEEE
 
» Maximization of Wind Energy Utilization Through Corrective Scheduling and FACTS Deployment
Abstract:
The paper proposes a probabilistic methodology for minimizing wind spillage and maximizing capacity of the deployed wind generation, whilst improving system reliability. Capacities of the connected wind units are initially determined by using a method developed by the industry. A probabilistic approach is applied for the day-ahead planning to find maximum deployable wind sources so that the prescribed wind spillage is not exceeded. This is done using the optimum power flow, where wind spillages are prioritised with the probabilistic “cost coefficients.” Further improvement of wind energy utilization is achieved by installing FACTS devices and making use of real-time thermal ratings. Two ranking lists are developed to prioritize location of SVCs and TCSCs, and they are then combined into a unified method for best FACTS placement. The entire methodology is realized in two sequential Monte Carlo procedures, and the probabilistic results are compared with the state enumeration ones. Results show improved wind utilization, network reliability, and economic aspects.
Autors: Alexandra Kapetanaki;Victor Levi;Muhammad Buhari;Jonathan Alexandre Schachter;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4764 - 4773
Publisher: IEEE
 
» Maximum Likelihood Estimation of Optical Path Length in Spectral Interferometry
Abstract:
Optical path length demodulation is a subject of fundamental importance in spectral interferometry applications. We propose an algorithm based on maximum likelihood estimation to achieve absolute optical path length demodulation with high sensitivity and noise resistance and to elucidate the cause and behavior of undesirable demodulation discontinuity. From an interference spectrum model with additive Gaussian noise, a maximum likelihood estimator is derived in Fourier domain to determine the optical path length. To assess its sensitivity performance, the Cramer–Rao bound of sensitivity is derived from Fisher information matrix. By simulations and experimental validations, the proposed method demonstrates its capability of achieving the Cramer–Rao bound over a large dynamic range of optical path lengths, initial phases, and signal-to-noise ratios. When compared with some state-of-the-art demodulation methods, it also demonstrates improved resistance to demodulation jumps at low signal-to-noise ratios. Importantly, the mechanism of such jumps can be readily explained from a new, intuitive perspective, which may permit the quantification of jump occurrences in the future.
Autors: Chengshuai Li;Shichao Chen;Yizheng Zhu;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:22, pages: 4880 - 4887
Publisher: IEEE
 
» Maximum Limit of Superconducting Persistent Current for Superconducting Magnetic Suspension System
Abstract:
Superconducting technique is applied to a superconducting magnetic suspension system. The suspension system is composed of a superconducting coil, a copper coil, a suspended object, a photo sensor, a PID controller, and power amplifiers. Persistent current in a superconducting coil and control current in a copper coil are used for suspending object and controlling object, respectively. In this paper, large-gap trial on the system is performed, and the static and dynamic characteristics of the suspended object are performed. As a result, it is found that the suspended object continues to suspend at a distance 43 mm for s. It is found that there is a maximum limit of superconducting persistent current for the system. The details of the superconducting persistent current are discussed. This may be the first trial that superconducting persistent current is used for a magnetic suspension system.
Autors: M. Komori;A. Minoda;K. Nemoto;K. Asami;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Mean Bit Error Rate Evaluation of MC-CDMA Cellular Systems Employing Multiuser-Maximum-Likelihood Detector
Abstract:
In this paper, we evaluate the uplink bit error rate (BER) of multicarrier-code-division-multiple-access (MC-CDMA) cellular systems with multiuser-maximum-likelihood detector (MU-MLD). The scenario considers perfect power control, own-cell interference (or multiple access interference—MAI), interference from co-cells (or co-cell interference—CCI), additive white Gaussian noise, exponential path-loss and slow frequency-selective Rayleigh fading. Upper bound expressions to evaluate the mean BER are obtained, which are functions of the signal-to-noise ratio (SNR), the number of users, the spreading factor, and the channel reuse factor. For BPSK and 4-QAM (quadrature amplitude modulation), closed-form expressions involving the analytical calculation of pairwise error probabilities are obtained. For 16-QAM and 64-QAM, we show that the number of pairwise error probabilities needed to obtain the BER can be simplified through the constellations symmetry. The procedure for obtaining this simplification is detailed. Also, by considering BER asymptotes, expressions for the SNR penalty due to MAI are derived. Monte Carlo simulations verify the analytical expressions accuracy. In the simulations, the MU-MLD is implemented through the sphere decoder algorithm with MMSE QR factorization. Results show that MC-CDMA does not lose diversity due to MAI. Moreover, CCI significantly affects the system performance. As a consequence, it produces floors in the BER curves.
Autors: Henry Ramiro Carvajal Mora;Nathaly Verónica Orozco Garzón;Celso de Almeida;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9838 - 9851
Publisher: IEEE
 
» Measurements of Sea Clutter at Low Grazing Angle in Mediterranean Coastal Environment
Abstract:
Results of a coastal measurement campaign called MediterraneAn Rfc and cLutter ENvironmental Experiment (MARLENE) are presented and studied. The campaign was held in spring 2014, on a DGA site in the Mediterranean Sea region of Toulon, France. Three coastal measurement radar systems, Millimeter wave Experimental Multifrequency Polarimetric High Resolution Interferometric System (Fraunhofer FHR), MARSIG (WTD 71), and MEDYCIS (ONERA), were deployed to simultaneously acquire sea clutter measurements. During the campaign, the in situ oceanic and meteorological conditions were characterized from the RV PLANET meteorological ship deployed by WTD 71 and by modeling from WAVEWATCH III and SWAN wave models. Radar measurements were performed at the C-, X-, Ku-, Ka-, and W-bands. The measurement results are presented in terms of reflectivity and mean Doppler spectrum according to low grazing angle and azimuth variations. Reflectivity variations are compared with the empirical GIT model and close results are obtained at the C- and Ka-bands. At the same frequency bands, mean Doppler Spectrum velocity is presented and analyzed according to grazing and azimuth angles. Physical interpretations of electromagnetic interaction with sea surface are discussed.
Autors: V. Fabbro;G. Biegel;J. Förster;J.-B. Poisson;A. Danklmayer;C. Böhler;J.-P. Marcellin;T. Brehm;M. Gallus;L. Castanet;A. Ulland;Y. Hurtaud;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6379 - 6389
Publisher: IEEE
 
» Measuring Scale-Up and Scale-Out Hadoop with Remote and Local File Systems and Selecting the Best Platform
Abstract:
MapReduce is a popular computing model for parallel data processing on large-scale datasets, which can vary from gigabytes to terabytes and petabytes. Though Hadoop MapReduce normally uses Hadoop Distributed File System (HDFS) local file system, it can be configured to use a remote file system. Then, an interesting question is raised: for a given application, which is the best running platform among the different combinations of scale-up and scale-out Hadoop with remote and local file systems. However, there has been no previous research on how different types of applications (e.g., CPU-intensive, data-intensive) with different characteristics (e.g., input data size) can benefit from the different platforms. Thus, in this paper, we conduct a comprehensive performance measurement of different applications on scale-up and scale-out clusters configured with HDFS and a remote file system (i.e., OFS), respectively. We identify and study how different job characteristics (e.g., input data size, the number of file reads/writes, and the amount of computations) affect the performance of different applications on the different platforms. Based on the measurement results, we also propose a performance prediction model to help users select the best platforms that lead to the minimum latency. Our evaluation using a Facebook workload trace demonstrates the effectiveness of our prediction model. This study is expected to provide a guidance for users to choose the best platform to run different applications with different characteristics in the environment that provides both remote and local storage, such as HPC cluster and cloud environment.
Autors: Zhuozhao Li;Haiying Shen;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3201 - 3214
Publisher: IEEE
 
» Measuring Target Range and Velocity: Developments in Chip, Antenna, and Packaging Technologies for 60-GHz and 122-GHz Industrial Radars
Abstract:
Increasing demand for industrial radars has spurred research aimed toward designing better transceiver (TRx) integrated circuits (ICs) combined with advanced packaging technologies [1]-[6], innovative antenna concepts, very precise wirebonding schemes [5]-[8], and high-performance baseband processing systems [9]. With a well-optimized package of such products, the resulting application fields can vary from avionics and robotics to automotive, monitoring, level-tracking, and vital-sign-detection systems, among many others. All these applications will require that the final product satisfy certain metrics such as range, resolution, accuracy, power consumption, and (as always) production cost, which is ultimately the most crucial criterion.
Autors: Efe Ozturk;Dieter Genschow;Uroschanit Yodprasit;Berk Yilmaz;Dietmar Kissinger;Wojciech Debski;Wolfgang Winkler;
Appeared in: IEEE Microwave Magazine
Publication date: Nov 2017, volume: 18, issue:7, pages: 26 - 39
Publisher: IEEE
 
» Medical Optical Imaging: Signal Processing Leads to New Methods of Detecting Life-Threatening Situations [Special Reports]
Abstract:
Autors: John Edwards;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 17 - 20
Publisher: IEEE
 
» Medium Stack Optimization for Microwave-Assisted Magnetic Recording
Abstract:
In this paper, we present systematic micromagnetic modeling investigation on recording process of segmented thin-film media with circularly polarized magnetic field at microwave frequencies. This paper provides insightful understanding about the segmented medium stack design in microwave-assisted magnetic recording (MAMR) by exploring the impact of signal-to-noise (SNR) ratio and recording track width. By utilizing segmentation of grains with exchange breaking layers, the ac magnetic field generated from spin torque oscillator can be best exploited. Via optimized medium stack design, MAMR is able to achieve both high SNR and areal density gain with the proposed notched-structure medium (top and bottom segments have the strongest crystalline anisotropy) compared with conventional graded medium (with gradually increasing anisotropy from top to bottom). By tuning crystalline anisotropy strength in top and bottom segment, we studied the MAMR behavior of SNR and track width under different ac frequencies. This provides a novel view for future segmented media design.
Autors: Xiaoyu Bai;Jian-Gang Zhu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 

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