Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 6

» Development of an Energy-Saving Controller for Sub Apparatus
Abstract:
An enormous energy has been consumed in a semiconductor manufacturing factory. The energy consumption ratio for the use of manufacturing apparatus is approximately 60% in a semiconductor manufacturing factory, and the cost of energy is increasing in recent years. Therefore, we develop an energy saving controller for saving the energy of sub apparatus. We introduce the controller for dry pump and gas detoxifying apparatus during wafer transfer steps. We succeed in reducing energy consumption approximately 17 percent per manufacturing apparatus. The energy saving controller has the feature of rationality for energy saving operation and usability for every sub apparatus.
Autors: Toshiya Ozaki;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 367 - 370
Publisher: IEEE
 
» Development of Compact Ultra-Low-Field MRI System Using an Induction Coil
Abstract:
Ultra-low-field magnetic resonance imaging (ULF-MRI) is attractive for MRI applications such as a concurrent system of magnetoencephalography (MEG) and MRI. We are developing a compact ULF-MRI system that can be combined with a small-animal MEG system. In this paper, we developed a detection method that uses an induction coil instead of a superconducting quantum interference device for the ULF-MRI. The induction coil has advantages such as being more robust, easy to handle, and flexible for designing. We fabricated an induction coil from a copper wire with dimensions of 29 mm mm mm (inner diameter outer diameter length). A capacitor was connected to increase the sensitivity by the LC resonance effect. The resonance frequency was 3 kHz, and the corresponding magnetic field density for MRI measurement was . The detection coil was integrated with the compact ULF-MRI system and placed inside a magnetically shielded box. MRI measurement was demonstrated by using water phantoms with a total volume of mm. The size of the obtained image was pixels for 30.2 mm mm. A clear shape of the water phantom was taken with this ULF-MRI system. This result shows the induction coil can be used for the compact ULF-MRI system.
Autors: Daisuke Oyama;Yoshiaki Adachi;Masanori Higuchi;Naohiro Tsuyuguchi;Gen Uehara;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Development of Equivalent 2-D Finite-Element Models for Accurate Prediction of Thrust Force in Permanent Magnet Lead Screws
Abstract:
This paper deals with equivalent 2-D finite-element (FE) models of permanent magnet lead screw (PMLS), to accurately predict the thrust force. Due to the helical-shape permanent magnets (PMs), the magnetic fields of PMLS are typically 3-D and non-symmetric. However, the PMLS is approximately symmetric in some cases and an equivalent 2-D axis-symmetric FE model is developed instead of 3-D models. The problem lies in that no evaluation about the accuracy and applicability of the 2-D axis-symmetric FE model was offered in previous literature. In this paper, the 2-D axis-symmetric FE model is derived based on the concept of equivalent current sheets of PMs. The limitations of the existing 2-D axis-symmetric FE model are clarified, and a novel equivalent 2-D torque FE model is then proposed to predict thrust force with the gear ratio when the 2-D axis-symmetric FE model is not appropriate. It is shown that the choice of equivalent 2-D FE model depends on the lead angle of PMLS, 2-D axis-symmetric FE model is applicable in the range of (0°, 15°), and 2-D torque FE model is preferred in the range of (65°, 90°).
Autors: Fang Gao;Qian Wang;Jibin Zou;Yongxiang Xu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Development of Reliable Gearless Motors for Electric Vehicles
Abstract:
In this paper, a new class of reliable gearless motors, dubbed as the magnetic steering (MS) motor, is proposed to realize the concept of the magnetic differential (MagD) system for direct-drive electric vehicles. While the electronic differential (ED) system can control two individual motors to provide the differential action in the absence of mechanical differential, it suffers from reliability concerns upon errors from the individual motors. The proposed MagD system instead utilizes the MS-field excitation to interlock the magnetic fields in two rotors of the MS motor. With the control of MS-field excitation, the two rotors can be differentiated to generate appropriate torque levels for two driving wheels. As a result, the MagD system can offer higher reliability than the ED system. The machine performances of the proposed MS motor are evaluated by finite-element analysis, and the operating performances of the proposed MagD system are testified by system-level simulation.
Autors: Christopher H. T. Lee;K. T. Chau;Libing Cao;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 8
Publisher: IEEE
 
» Dielectric Characterization at Millimeter Waves With Hybrid Microstrip-Line Method
Abstract:
This paper proposes a hybrid microstrip-line method for characterizing materials with unknown dielectric properties at millimeter-wave (mm-Wave) frequencies. The proposed method introduces two error boxes, representing the impedance mismatch and discontinuities caused by signal path transitions between two different types of transmission lines. Therefore, unlike conventional covered- or two-transmission-line methods, the proposed method requires neither a perfect impedance match between the test fixture and the coaxial cables nor a high reproducibility of the transitions' radio frequency characteristics. We applied the proposed method to characterize two types of dielectric materials: Rogers RT/d5880 standard high-frequency substrate and a plain-woven polyester fabric substrate, using a single setup with an in-house designed universal test fixture in the 37-39 GHz range. The accuracy of the proposed method under imperfect fixture conditions is demonstrated.
Autors: Xiaoyou Lin;Boon-Chong Seet;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 3100 - 3102
Publisher: IEEE
 
» Differential Dual-Band Filters With Flexible Frequency Ratio Using Asymmetrical Shunt Branches for Wideband CM Suppression
Abstract:
In this paper, a group of differential dual-band bandpass filters based on a single quad-mode stub-loaded twin-ring resonator (TRR) are presented, which utilize asymmetrical shunt branches for common-mode (CM) suppression. Under differential-mode (DM) operation, the stub-loaded TRR manifests quad-mode characteristic for dual-band design. The frequency ratio of the two passbands can be flexibly selected according to the form of the loaded stubs. Different from the inline topology, differential multimode structures inevitably suffer from the hardship in CM suppression, especially for dual-band designs. Despite previous work fulfilled moderate CM suppression via embedded defected ground structure units, but the CM noise in the DM lower band can just be shifted away rather than suppressed. Instead, a novel CM-suppression approach is devised attributing to the asymmetrical short-terminated branches along the bisection line of the TRR. The transmission of the CM noise near the DM passbands can be blocked effectively. Furthermore, multiple CM notches can be obtained by the cooperation of the asymmetrical branches and source–load coupling, leading to the favorable CM suppression in a wide frequency range. For verification, a prototype differential dual-band filter based on the open stub-loaded TRR has been realized with frequency ratio which is larger than two. Similarly, a differential dual-band filter using the short-circuited stub-loaded TRR is also presented as an extension for frequency ratio which is smaller than two. The simulation and experiment results of the two demonstrated filters are given, showcasing a good agreement.
Autors: Li-Heng Zhou;Jian-Xin Chen;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Nov 2017, volume: 65, issue:11, pages: 4606 - 4615
Publisher: IEEE
 
» Differential Protection With Critical Motors and Motor Applications: What You Didn't Know
Abstract:
The application of differential protection has been shown to be effective in many applications within the forest product-based industries. However, there are some aspects of differential protection that need special consideration. Some differential configurations may be harmful to the systems they were installed to protect. This article will cover a few of the basics surrounding typical differential applications. Also highlighted are some of the risk areas that are typically overlooked when applying differential protection for certain applications.
Autors: John A. Kay;David C. Mazur;Kenneth D. Mazur;
Appeared in: IEEE Industry Applications Magazine
Publication date: Nov 2017, volume: 23, issue:6, pages: 62 - 70
Publisher: IEEE
 
» Digital Payments in India: The Road Ahead
Abstract:
India is a vast country with a population of more than 1.3 billion, with nearly one-seventh of its residents living in rural areas. However, India is blessed with a young demographic profile with half of the population younger than 21 years of age.
Autors: Ashish Das;Praggya Das;
Appeared in: IEEE Potentials
Publication date: Nov 2017, volume: 36, issue:6, pages: 14 - 19
Publisher: IEEE
 
» Digital Predistortion of Wideband Power Amplifier With Single Undersampling ADC
Abstract:
A novel direct-learning digital predistortion (DPD) of power amplifier (PA) is proposed to alleviate the requirement of an analog-to-digital converter (ADC) in the feedback path. Different from existing undersampling methods, the proposed approach requires only a single ADC running at low sampling rate, which saves one-half hardware cost and avoids the I/Q imbalance problem of the conventional zero-IF feedback structure. First, a modified Gauss-Newton iteration using a low-rate single-branch feedback signal is derived, which justifies the use of single undersampling ADC. Second, a low-complexity time and phase synchronization algorithm based on pattern cross correlation is presented, to align the input and output samples. Experimental results on a 10-W class-AB wideband PA and 100-MHz LTE-A test signal show that the proposed approach can effectively linearize the PA and outperforms other undersampling DPD approaches using the conventional zero-IF feedback structure, in terms of adjacent channel leakage ratio.
Autors: Ning Guan;Nan Wu;Hua Wang;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 1016 - 1018
Publisher: IEEE
 
» DIO Suppression Attack Against Routing in the Internet of Things
Abstract:
Recent standardization efforts are consolidating the role of routing protocol for low-power and lossy networks (RPL) as the standard routing protocol for IPv6-based wireless sensor and actuator networks. Investigating possible attacks against RPL is a top priority to improve the security of the future Internet of Things systems. In this letter, we present the DIO suppression attack, a novel degradation-of-service attack against RPL. Unlike other attacks in the literature, the DIO suppression attack does not require to steal cryptographic keys from some legitimate node. We show that the attack severely degrades the routing service, and it is far less energy-expensive than a jamming attack.
Autors: Pericle Perazzo;Carlo Vallati;Giuseppe Anastasi;Gianluca Dini;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2524 - 2527
Publisher: IEEE
 
» Direct and Indirect Model Reference Adaptive Control for Multivariable Piecewise Affine Systems
Abstract:
This article proposes direct and indirect model reference adaptive control strategies for multivariable piecewise affine systems, which constitute a popular tool to model hybrid systems and approximate nonlinear systems. A chosen reference model, which can be linear or also piecewise affine, describes the desired closed-loop system behavior that is to be achieved by the adaptive controllers for unknown system dynamics. Each subsystem acquires its own set of control gains, which is tuned under careful consideration of the switching behavior. In the indirect approach, the use of dynamic gain adjustment avoids singularities in the certainty equivalence principle. It is shown for both algorithms that the state of the reference model is tracked asymptotically given a common Lyapunov function for the switched reference model is available. Furthermore, parameter convergence in both the direct and indirect approach is proven for sufficiently rich reference signals. Finally, both algorithms are evaluated in numerical simulations and their advantages and disadvantages are discussed.
Autors: Stefan Kersting;Martin Buss;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5634 - 5649
Publisher: IEEE
 
» DIRSIG5: Next-Generation Remote Sensing Data and Image Simulation Framework
Abstract:
The digital imaging and remote sensing image generation model is a physics-based image and data simulation model that is primarily used to generate synthetic imagery across the visible to thermal infrared regions using engineering-driven descriptions of remote sensing systems. The model recently went through a major redesign and reimplementation effort to address changes in user requirements and numerical computation trends that have emerged in the 15 years since the last major development effort. The new model architecture adopts some of the latest light transport algorithms matured by the computer graphics community and features a framework that is easily parallelized at the microscale (multithreading) and macroscale (cluster-based computing). A detailed description of the framework is provided, including a novel method for efficiently storing, evaluating, integrating, and sampling spherical and hemispherical datasets appropriate for the representation of modeled or measured bidirectional scattering, reflectance, and transmission distribution functions. The capabilities of the model are then briefly demonstrated and cross-verified with scenarios of interest to the remote sensing community.
Autors: Adam A. Goodenough;Scott D. Brown;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 4818 - 4833
Publisher: IEEE
 
» Discrete Numerical Approach to the Fredholm Integral Method for Evaluating Scattering by Irregular Dielectric Particles
Abstract:
A new approach to the implementation of the Fredholm integral method (FIM) was developed to evaluate scattering by irregular dielectric particles. In this paper, particles are modeled discretizing their volume with cells according to their weighted contents. The approach to FIM presented in this paper represents a departure from earlier work where the numerical integration is no longer based on expansion in a set of polynomials but on direct spatial integration. This approach which still involves contour integration method uses quandrantal contour in combination with a conditioning weighting function to control the magnitude of the integrand due to the power of the radial variable in the integrand being odd. The strength of our approach lies on the fact that computations are performed in the spatial frequency domain. As a result, the angular scattering pattern is strongly connected to the spatial Fourier transform of the scatterer; hence, for electrically small particles the angular spectrum is relatively smooth and the number of pivots required for integration is relatively low. This technique is well suited to the treatment of scattering from irregular inhomogeneous dielectric particles since only the distribution in space of the dielectric constants needs to be defined. Numerical results also confirm the inadequacy of effective medium theories in evaluating scattering characteristics of inhomogeneous particles.
Autors: Felix Ngobigha;David Bebbington;Laura Carrea;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5949 - 5959
Publisher: IEEE
 
» Discriminant Analysis of Hyperspectral Imagery Using Fast Kernel Sparse and Low-Rank Graph
Abstract:
Due to the high-dimensional characteristic of hyperspectral images, dimensionality reduction (DR) is an important preprocessing step for classification. Recently, sparse and low-rank graph-based discriminant analysis (SLGDA) has been developed for DR of hyperspectral images, for which the properties of sparsity and low-rankness are simultaneously exploited to capture both local and global structures. However, SLGDA may not achieve satisfactory results when handling complex data with nonlinear nature. To address this problem, this paper presents two kernel extensions of SLGDA. In the first proposed classical kernel SLGDA (KSLGDA), the kernel trick is exploited to implicitly map the original data into a high-dimensional space. With a totally different perspective, we further propose a Nyström-based kernel SLGDA (KSLGDA) by constructing a virtual kernel space by the Nyström method, in which virtual samples can be explicitly obtained from the original data. Both KSLGDA and KSLGDA can achieve more informative graphs than SLGDA, and offer superiority over other state-of-the-art DR methods. More importantly, the KSLGDA can outperform KSLGDA with much lower computational cost.
Autors: Lei Pan;Heng-Chao Li;Wei Li;Xiang-Dong Chen;Guang-Ning Wu;Qian Du;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6085 - 6098
Publisher: IEEE
 
» Dissimilarity-Weighted Sparse Representation for Hyperspectral Image Classification
Abstract:
To improve the capability of a traditional sparse representation-based classifier (SRC), we propose a novel dissimilarity-weighted SRC (DWSRC) for hyperspectral image (HSI) classification. In particular, DWSRC computes the weights for each atom according to the distance or dissimilarity information between the test pixel and the atoms. First, a locality constraint dictionary set is constructed by the Gaussian kernel distance with a suitable distance metric (e.g., Euclidean distance). Second, the test pixel is sparsely coded over the new weighted dictionary set based on the -norm minimization problem. Finally, the test pixel is classified by using the obtained sparse coefficients with the minimal residual rule. Experimental results on two widely used public HSIs demonstrate that the proposed DWSRC is more efficient and accurate than other state-of-the-art SRCs.
Autors: Le Gan;Junshi Xia;Peijun Du;Zhigang Xu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1968 - 1972
Publisher: IEEE
 
» Distributed Active Anti-Disturbance Consensus for Leader-Follower Higher-Order Multi-Agent Systems With Mismatched Disturbances
Abstract:
This technical note studies the finite-time consensus problem of leader-follower higher-order multi-agent systems with mismatched disturbances. To solve such a problem, by combining the non-singular terminal sliding-mode control (NTSMC) and disturbance observer based control (DOBC) methods together, a distributed active anti-disturbance cooperative control scheme is proposed. Firstly, to estimate the matched/mismatched disturbances of each follower, a finite-time disturbance observer is constructed. Secondly, by distributedly employing the mismatched disturbances estimates, integral-type non-singular terminal sliding-mode surfaces are designed for followers. Thirdly, distributed protocols are proposed based on the surfaces. In the presence of mismatched disturbances, these protocols achieve finite-time output consensus for the agents. Simulations validate the correctness and effectiveness of the proposed control scheme.
Autors: Xiangyu Wang;Shihua Li;Xinghuo Yu;Jun Yang;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5795 - 5801
Publisher: IEEE
 
» Distributed Congestion Management of Distribution Grids Under Robust Flexible Buildings Operations
Abstract:
Flexible demand side energy and reserve procurement have the potential to improve the overall operation of the grid. However, as argued in previous studies, this flexibility might cause congestion in distribution grids. In this paper, we improve the conventional distribution locational marginal price (DLMP) method, while integrating congestion free energy and reserve provision from buildings in distribution grids. First, robust day-ahead (DA) DLMPs are calculated to account for unmodeled dynamics of flexible loads. Second, using dual decomposition, the data sharing requirements between the aggregator and the distribution system operator are minimized. Third, a sensitivity-based real-time adjustment method is presented to remove the conservatism of DA robust DLMPs. Case studies are performed on a benchmark distribution system. The numerical results show that the proposed technique efficiently handles load uncertainties and data sharing requirements, improving the practicality of the conventional DMLP method.
Autors: Sarmad Hanif;H. B. Gooi;Tobias Massier;Thomas Hamacher;Thomas Reindl;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4600 - 4613
Publisher: IEEE
 
» Distributed Database and Application Architecture for Big Data Solutions
Abstract:
In this paper, we report about platform and architecture that real-time analysis of big data are possible, and structured IT infrastructure that they are optimally combined. We developed a distributed architecture which the data conversion and the abnormality determination are multi-blocked. Furthermore, by selecting a distributed storage database (DB), we succeeded in constructing IT infrastructure capable of high-speed processing at a large number of manufacturing sites. In the new IT infrastructure, we achieved resource leveling of the application server and improvement of data processing time. It is expected that data file stagnation and delay of DB registration can be resolved.
Autors: Makoto Misaki;Tomio Tsuda;Shinji Inoue;Shintaro Sato;Akihiro Kayahara;Shin-Ichi Imai;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 328 - 332
Publisher: IEEE
 
» Distributed Downlink Power Control for Dense Networks With Carrier Aggregation
Abstract:
Given the proven benefits cell densification brings in terms of capacity and coverage, it is certain that 5G networks will be even more heterogeneous and dense. However, as smaller cells are introduced in the network, interference will inevitably become a serious problem as they are expected to share the same radio resources. Another central feature envisioned for future cellular networks is carrier aggregation (CA), which allows users to simultaneously use several component carriers of various widths and frequency bands. By exploiting the diversity of the different carriers, CA can also be used to effectively mitigate the interference in the network. In this paper, we leverage the above key features of next-generation cellular networks and formulate a downlink power setting problem for the different available carriers. Using game theory, we design a distributed algorithm that lets cells dynamically adjust different transmit powers for the different carriers. The proposed solution greatly improves network performance by reducing interference and power consumption, while ensuring coverage for as many users as possible. We compare our scheme with other interference mitigation techniques, in a realistic large-scale scenario. Numerical results show that our solution outperforms the existing schemes in terms of user throughput, energy, and spectral efficiency.
Autors: Zana Limani Fazliu;Carla-Fabiana Chiasserini;Gian Michele Dell’Aera;Enver Hamiti;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Nov 2017, volume: 16, issue:11, pages: 7052 - 7065
Publisher: IEEE
 
» Distributed Observer-Based Cyber-Security Control of Complex Dynamical Networks
Abstract:
Distributed tracking problem for complex dynamical networks with Lipschitz-type nonlinear dynamics under the framework of cyber-physical systems is investigated. Due to practical limitations in some circumstances, the states of the agents are usually unavailable for controllers, so distributed observers used to reconstruct the states of nodes are needed, which will be first designed. Differing from other studies of observer-based control problems for complex dynamical networks and multi-agent systems, it considers here the scenario that the communication channels for controllers and observers may be subjected to frequently malicious attacks, which will destroy the communication links and result in disconnected topologies of the communication networks. It is assumed that the impacts of attacks on different communication networks are different and independent. New security control strategies are proposed and analyzed. An algorithm to properly select the feedback gain matrices and coupling strengths is presented. By utilizing the Lyapunov stability theory, sufficient conditions are derived to check whether final consensus tracking can be achieved against such attacks. Finally, a simulation example comparing the security control and uncontrolled scenarios is demonstrated to show the effectiveness of the theoretical results.
Autors: Ying Wan;Jinde Cao;Guanrong Chen;Wei Huang;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Nov 2017, volume: 64, issue:11, pages: 2966 - 2975
Publisher: IEEE
 
» Distributed Optimization Decomposition for Joint Economic Dispatch and Frequency Regulation
Abstract:
Economic dispatch and frequency regulation are typically viewed as fundamentally different problems in power systems and, hence, are typically studied separately. In this paper, we frame and study a joint problem that co-optimizes both slow timescale economic dispatch resources and fast timescale frequency regulation resources. We show how the joint problem can be decomposed without loss of optimality into slow and fast timescale subproblems that have appealing interpretations as the economic dispatch and frequency regulation problems, respectively. We solve the fast timescale subproblem using a distributed frequency control algorithm that preserves network stability during transients. We solve the slow timescale subproblem using an efficient market mechanism that coordinates with the fast timescale subproblem. We investigate the performance of our approach on the IEEE 24-bus reliability test system.
Autors: Desmond Cai;Enrique Mallada;Adam Wierman;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4370 - 4385
Publisher: IEEE
 
» Distributed Sensor Coordination Algorithms for Efficient Coverage in a Network of Heterogeneous Mobile Sensors
Abstract:
Controlled mobility of nodes in mobile sensor networks allows for autonomous deployment and further optimization of network coverage after initial deployment. When sensor nodes have non-identical sensing ranges, more sophisticated optimization techniques should be used to solve for distributed relocation algorithms that maximize coverage. In this work, novel geometric methods are presented to address this problem. The proposed iterative algorithms use the available local information to judiciously relocate mobile sensors to new positions. This process leads to a continuous reduction in the size of coverage gaps throughout the field. Simulation results demonstrate the performance of the proposed algorithms in improving network coverage.
Autors: Hamid Mahboubi;Kaveh Moezzi;Amir G. Aghdam;Kamran Sayrafian-Pour;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5954 - 5961
Publisher: IEEE
 
» Distributed Torque Control of Deloaded Wind DFIGs for Wind Farm Power Output Regulation
Abstract:
In this work, we propose a distributed control methodology that solves the problem of dispatching and regulating the power outputs of a group of deloaded wind double-fed induction generators (DFIGs) to attain fast, dynamic, and efficient wind farm power output regulation, with fair load-sharing among the DFIGs. In this context, fair load-sharing means that the ratio defined by the mechanical power over the maximum power from the wind, i.e., the utilization level, of all DFIGs, is the same in the steady state. Dynamic distributed dispatch and control of the power outputs of DFIGs refers to their ability to self-dispatch and regulate their power outputs under dynamical conditions and through peer-to-peer information exchange. Initially, we propose a leader–follower consensus protocol that DFIGs can adopt into their control system to attain: 1) asymptotic consensus on their utilization levels (i.e., fair load-sharing), and 2) total power output regulation. Then, we perform compositional stability analysis and prove that the protocol asymptotically converges under sufficient conditions. Finally, we design a distributed control-Lyapunov-function-based torque controller for the rotor-side converter that realizes the protocol in practice. The performance of the distributed control methodology is evaluated through numerical simulations on the modified IEEE 24-bus RT system.
Autors: Stefanos Baros;Marija D. Ilić;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4590 - 4599
Publisher: IEEE
 
» Distributed Velocity-Constrained Consensus of Discrete-Time Multi-Agent Systems With Nonconvex Constraints, Switching Topologies, and Delays
Abstract:
In this technical note, a distributed velocity-constrained consensus problem is studied for discrete-time multi-agent systems, where each agent's velocity is constrained to lie in a nonconvex set. A distributed constrained control algorithm is proposed to enable all agents to converge to a common point using only local information. The gains of the algorithm for all agents need not to be the same or predesigned and can be adjusted by each agent itself based on its own and neighbors' information. It is shown that the algorithm is robust to arbitrarily bounded communication delays and arbitrarily switching communication graphs provided that the union of the graphs has directed spanning trees among each certain time interval. The analysis approach is based on multiple novel model transformations, proper control parameter selections, boundedness analysis of state-dependent stochastic matrices1, exploitation of the convexity of stochastic matrices, and the joint connectivity of the communication graphs. Numerical examples are included to illustrate the theoretical results.
Autors: Peng Lin;Wei Ren;Huijun Gao;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5788 - 5794
Publisher: IEEE
 
» DNN-Based Predictive Magnetic Flux Reference for Harmonic Compensation Control in Magnetically Unbalanced Induction Motor
Abstract:
A stator inter-turn fault occurring in one of the phases of a three-phase induction motor (IM) gives rise to high harmonics distortion in air-gap flux density, increased torque ripple, temperature rise in the stator windings, and mechanical vibrations due to varying magnetic forces and magnetic noise. The fault leads to a change in the electromagnetic field generated when compared to that during the normal motor operation. An incipient stator fault leads to variation of machine’s parameters, causing malfunction of the motor drive. Hence, it is of significant importance to detect the incipient fault before complete motor breakdown occurs. In this paper, a novel magnetic flux reference predictive method for control has been presented by using a harmonic compensation block in coordination with deep neural network (DNN) as a feedforward method to continue safe operation of motor after occurrence of incipient stator fault. This method takes into account both time and space harmonics discrepancies produced due to the fault. The proposed method has been implemented on a 7.5 hp IM using online observer of unhealthy conditions and compensated using DNN predictive methodology.
Autors: Eshaan Ghosh;Aida Mollaeian;Seog Kim;Jimi Tjong;Narayan C. Kar;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 7
Publisher: IEEE
 
» Does $ell _{p}$ -Minimization Outperform $ell _{1}$ -Minimization?
Abstract:
In many application areas ranging from bioinformatics to imaging, we are faced with the following question: can we recover a sparse vector from its undersampled set of noisy observations , . The last decade has witnessed a surge of algorithms and theoretical results to address this question. One of the most popular schemes is the -regularized least squares given by the following formulation:, where . Among these optimization problems, the case , also known as LASSO, is the best accepted in practice, for the following two reasons. First, thanks to the extensive studies performed in the fields of high-dimensional statistics and compressed sensing, we have a clear picture of LASSO’s performance. Second, it is convex and efficient algorithms exist for finding its global minima. Unfortunately, neither of the above two properties hold for . However, they are still appealing because of the following folklores in the high-dimensional statistics. First, is closer to than . Second, if we employ iterative methods that aim to converge to a local minima of , then under good initialization, these algorithms converge to a solution that is still closer to than . In spite of the existence of plenty of empirical results that support these folklore theorems, the theoretical progress to establish them has been very limited. This paper aims to study the above-mentioned folklore theorems and establish their scope of validity. Starting with approximate message passing (AMP) algorithm as a heuristic method for solving -regularized least squares, we study the following questions. First, what is the impact of initialization on the performance of the algorithm? Second, when does the algorithm recover the sparse signal under a “good” initialization? Third, when does the algorithm converge to the sparse signal regardless of the initialization? Studying these questions will not only shed light on the second folklore theorem, but also lead us to the answer the first one, i.e., the performance of the global optima . For that purpose, we employ the replica analysis1 to show the connection between the solution of AMP and in the
Autors: Le Zheng;Arian Maleki;Haolei Weng;Xiaodong Wang;Teng Long;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 6896 - 6935
Publisher: IEEE
 
» Domain Structure and Spin Reorientation in TbCo5 and DyCo5 Intermetallics
Abstract:
In this paper, we study the spin-reorientation processes in DyCo5 and TbCo5 intermetallic compounds by direct observation of domain structure (DS) realignment during the easy plane—easy cone—easy axis phase transitions. In addition to the analysis of DS changes due to temperature induced spin reorientation, a description is given of a newly discovered effect of surface out-of-plane domain reorientation produced by abrasion and/or indentation of the surface of macroscopic samples with overall easy-plane magnetocrystalline anisotropy.
Autors: R. M. Grechishkin;A. I. Ivanova;A. N. Grachev;A. D. Zigert;R. M. Eguzhokova;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Domain Wall Interconnections for NML
Abstract:
Nanomagnet logic (NML) is one of the most novel solutions studied as complementary technology to CMOS transistors. Information propagation involves only a change in spin orientation, no charge movement is present. Since the basic element is a nanomagnet, NML circuits have no stand-by power consumption and the ability to mix logic and memory in the same device. While CMOS is a multilayer technology, until now NML is confined to one single physical layer. The consequence is that circuit area grows exponentially due to interconnections overhead. In this paper, we present an innovative solution that drastically reduces the area wasted for interconnection wires relying on the properties of domain walls (DWs). We mix DWs and NML technologies in a unique DW logic (DWL) solution that exploits the advantages of both technologies. The proposed solution is technologically compatible with up-to-date fabrication processes. All the results here presented for the NML logic blocks and the DWs interconnections and their combination are obtained through rigorous micromagnetic simulations. Moreover, we implemented as a case study an high performance adder (Pentium 4 adder) and evaluated its features with increasing parallelism and compared with the simple NML implementation in order to explore the potential of DWL technology at circuit and architectural level. The reduction in circuit area corresponds to a notable reduction in both the latency and power consumption. The improvements in NML technology are shown by both the remarkable performance improvement and new possibilities offered by this novel solution.
Autors: Fabrizio Cairo;Marco Vacca;Giovanna Turvani;Maurizio Zamboni;Mariagrazia Graziano;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 3067 - 3076
Publisher: IEEE
 
» Doubly Salient Dual-PM Linear Machines for Regenerative Shock Absorbers
Abstract:
In order to fully utilize the high-energy nature of permanent magnet (PM) material, the stator-PM structure and the mover-PM structure of linear machines are integrated into one doubly salient PM machine topology, leading to a new class of doubly salient dual-PM linear machines. In essence, PMs are mounted on both the stator and mover iron cores while avoiding magnetic saturation, hence offering the high force density and high power density. Meanwhile, it consists of a fault-tolerant tooth stator and a consequent-pole mover, which can provide the fault-tolerant capability and exert the salient effect, respectively. By using finite-element analysis, the proposed machine is optimized for application to regenerative shock absorbers which can provide on-board renewable energy harvesting in vehicles. The machine performances are analyzed and quantitatively compared with that of its counterparts including the stator-PM linear machine and the mover-PM linear machine. Moreover, both the flat and tubular morphologies of the proposed machine are quantitatively compared and discussed.
Autors: Hua Fan;K. T. Chau;Chunhua Liu;Wenlong Li;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Dual Active Resonator for Dispersion Coefficient Measurement of Asphaltene Nano-Particles
Abstract:
Dispersion and diffusion of Asphaltene particles in -Heptane is measured to investigate the solution characteristics of different concentrations in wide range of 0.000625–0.625 (%wt). Planar split ring resonator (SRR) is armed with active circuitry (active resonator) to enhance the quality factor over 3 K to achieve ultra-high resolution sensing and track minute variations in microfluidic tube. Parallel SRRs as dual active resonator are performing independently, both in sensing and resolution, at 1.03 GHz () and 1.149 GHz () as the sensing tool in non-contact mode to monitor the spread of model oil (short pulse) in -Heptane (continuous flow). With the frequency shifts (, ), average flow rate, and the inner diameter of the tube, the molecular diffusion coefficient, and then the dispersion coefficient can be rapidly derived according to two-window solution of Taylor-Aris dispersion analysis. Samples with higher concentration of Asphaltene are shown to have faster spread and larger dispersion in the flow. Dispersion coefficients of the samples cover the range of 5.2– mm2/s in great agreement with conventional methods.
Autors: Mohammad Abdolrazzaghi;Mojgan Daneshmand;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7248 - 7256
Publisher: IEEE
 
» Dual Capacity Upper Bounds for Noisy Runlength Constrained Channels
Abstract:
Binary-input memoryless channels with a run length constrained input are considered. Upper bounds to the capacity of such noisy run length constrained channels are derived using the dual capacity method with Markov test distributions satisfying the Karush-Kuhn-Tucker conditions for the capacity-achieving output distribution. Simplified algebraic characterizations of the bounds are presented for the binary erasure channel and the binary symmetric channel. These upper bounds are very close to achievable rates, and improve upon previously known feedback-based bounds for a large range of channel parameters. For the binary-input additive white Gaussian noise channel, the upper bound is simplified to a small-scale numerical optimization problem. These results provide some of the simplest upper bounds for an open capacity problem that has theoretical and practical relevance.
Autors: Andrew Thangaraj;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7052 - 7065
Publisher: IEEE
 
» Dual Tuning of Doubly Hybridized Spin-Electromagnetic Waves in All-Thin-Film Multiferroic Multilayers
Abstract:
Theoretical investigation of dual (electric and magnetic) tuning of dispersion characteristics has been studied for the doubly hybridized spin-electromagnetic waves (SEWs) propagating perpendicularly to the direction of static magnetization in tangentially magnetized all-thin-film multiferroic multilayers. The multilayers consisted of two thin ferrite films separated by a thin ferroelectric film. The SEW spectrum was formed as the result of the double hybridization among one electromagnetic mode and two spin-wave modes. Such hybridization took place if the initial dispersion characteristics of these modes were degenerated. The electric tuning was realized owing to the changing of the magneto-dipole interaction between the magnetic films caused by a variation of dielectric constant of the ferroelectric film. It was shown that a decrease in permittivity of the ferroelectric film of micrometer thickness by a factor of two induces change of the SEW wavenumber up to tens of radian per centimeter.
Autors: Aleksei A. Nikitin;Vitaliy V. Vitko;Andrey A. Nikitin;Alexandr V. Kondrashov;Alexey B. Ustinov;Alexander A. Semenov;Erkki Lähderanta;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Dual-Band Magnetoelectric Dipole Antenna With Dual-Sense Circularly Polarized Character
Abstract:
In this paper, a dual-band dual-sense circularly polarized (CP) magnetoelectric dipole antenna is proposed. The antenna consists of a cavity reflector, two pairs of vertical and horizontal copper plates, and a crossed -shaped feeding structure. The shorted vertical plates work as quasi-magnetic dipoles (M-dipoles), while the connected horizontal plates work as electric dipoles (E-dipoles). Two M-dipoles and E-dipoles are designed to possess different heights and lengths, and thus they are able to achieve separate operation bands. To generate dual-sense CP performance, the M-dipoles and E-dipoles are placed in parallel and the adjacent E-dipoles extend along the opposite directions. Benefiting from the intrinsic 90° phase difference between the M-dipole and E-dipole, the left-hand CP is achieved within the lower operation band (2.15–3.4 GHz) and the right-hand CP is achieved within the upper band (4–6.3 GHz). The proposed antenna possesses a unidirectional radiation pattern with high front-to-back ratio ( dB). Furthermore, high gain ( dBi) and radiation efficiency (%) are also achieved.
Autors: Jun Tao;Quanyuan Feng;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5677 - 5685
Publisher: IEEE
 
» Dual-Band Microstrip Balun With Flexible Frequency Ratio and High Selectivity
Abstract:
A new planar microstrip balun with two operation bands is presented and investigated in this letter. Originated from the traditional Marchand balun, the proposed dual-band balun is designed on a symmetrical four-port network with one short-circuited port. Derived equations and design charts show that the frequency ratio () of these two bands could be flexibly controlled in a wide range of 2.0–4.6. Moreover, inherent transmission zeros nearby each band have been introduced into this dual-band balun, aiming to improve the frequency selectivity. For verification, a prototype dual-band balun operating at 2.4 and 5.2 GHz () is implemented and measured. Both simulation and measured results are recorded with good agreement.
Autors: Feng Huang;Jianpeng Wang;Lei Zhu;Quangang Chen;Wen Wu;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Nov 2017, volume: 27, issue:11, pages: 962 - 964
Publisher: IEEE
 
» Dual-Band Orthogonally Polarized Single-Layer Reflectarray Antenna
Abstract:
Design and implementation of a dual-band and orthogonally polarized single-layer microstrip reflectarray are presented in this communication. The proposed reflectarray operates in two separated broad frequency bands within - and -bands. The reflectarray element consists of a circular patch surrounded by a microstrip ring. Two curved phase delay lines are attached to the patch and two curved phase delay lines are attached to the ring. The ring and patch are designed for the operation at - and -bands, respectively. Phase delay lines attached to the ring are spatially rotated by 90° with respect to the delay lines attached to the patch. This produces a linear polarization at -band, which is perpendicular to the linear polarization produced at -band. This also provides a high polarization isolation, which enables by adjusting the phase of the elements at each band independent of the phase at the other bands. At both operation bands, the required phase shifts are obtained by varying the lengths of the phase delay lines. The proposed element provides more than 450° linear phase range over the bands 8.7–10.7 GHz (-band) and 18–20.4 GHz (-band). Measurement results show the maximum gain of 27.7 dB at 9.7 GHz with 25% 1 dB gain bandwidth and the maximum gain of 31.8 dB at 19.2 GHz wit- 18% 1 dB gain bandwidth. By proper arrangement of the elements in the array, the cross polarization is reduced. The measured efficiency is 63% at 9.7 GHz and 42% at 19.2 GHz with a center-fed design for the reflectarray.
Autors: R. Shamsaee Malfajani;B. Abbasi Arand;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6145 - 6150
Publisher: IEEE
 
» Dual-Layer Dielectric Stack for Thermally Isolated Low-Energy Phase-Change Memory
Abstract:
High reset energy is an ongoing issue for phase-change memory (PCM) devices. Prior work demonstrates that smaller PCM switching volume and thermal isolation can reduce the reset energy. In this paper, we fabricate and measure a planar confined PCM device with a multilayer dual-layer stack (DLS) of SiO2/Al2O3 insulator. Devices with contact area of 500 20 nm and lengths of show exceptionally low reset energies of 18.25 ± 15.8 pJ and low reset current densities of 0.94 ± 0.51 MA/cm2. Implementing the DLS enables a 60% reduction in reset energy compared with SiO2-isolated devices.
Autors: Scott W. Fong;Christopher M. Neumann;Eilam Yalon;Miguel Muñoz Rojo;Eric Pop;H.-S. Philip Wong;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4496 - 4502
Publisher: IEEE
 
» Dual-Port Planar Antenna for Implantable Inductively Coupled Sensors
Abstract:
Passive implantable sensors have received considerable attention for wireless in vivo measurement of physiological parameters in challenging locations of the human body. They are considered promising alternatives to the existing catheter-based biomedical transducers and battery powered implants. In this paper, we report a novel planar reader antenna for wireless interrogation of -based passive implantable sensors. The antenna utilizes two planar, electromagnetically isolated loops for wireless detection of the resonance frequency of the sensors. 2-D and 3-D versions of the antenna with the identical geometry were developed for a comparative study. A comprehensive analysis of the antenna together with in vitro evaluation of the antenna performance is presented. With the proposed antenna topology, the isolation level of 58 dB within the frequency range of 1–50 MHz, and at least 37 dB up to 100 MHz was achieved. The 3-D version of the antenna demonstrated improved performance by the T/R isolation of at least 64 and 44 dB within the frequency bands of 1–50 and 50–100 MHz, respectively.
Autors: Mohammad H. Behfar;Lauri Sydänheimo;Shuvo Roy;Leena Ukkonen;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5732 - 5739
Publisher: IEEE
 
» Duration-Variable Participant Recruitment for Urban Crowdsourcing With Indeterministic Trajectories
Abstract:
For urban crowdsourcing applications, the data sensing tasks can be achieved by vehicles traveling on the roads, which can save the expenses on constructing dedicated infrastructures. In this paper, to efficiently handle the crowdsourcing recruitment problem, we propose to recruit participants with the duration-variable principle and prove that it performs better compared to the strategy that recruits vehicles for all required time periods. The duration-variable principle enables recruitment of vehicular sensing resources across different time epochs to maximize the crowdsourcing profits. To ensure the utilization of limited budget, we formulate the duration-variable participant recruitment (DPR) problem with the consideration of indeterministic trajectories to determine which vehicle subset is chosen and how many epochs are provided for each selected vehicle. Since the formulated problem is NP-hard, we propose a two-step DPR algorithm by maximizing the available sensing resource utilization efficiency in each recruitment round, which is shown to be near-optimal and has low computational complexity. Experiments on real traces show that the proposed DPR scheme exceeds three other solutions in providing higher spatial coverage for urban crowdsourcing applications.
Autors: Miao Hu;Zhangdui Zhong;Yong Niu;Minming Ni;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10271 - 10282
Publisher: IEEE
 
» DVFS-Based Long-Term Task Scheduling for Dual-Channel Solar-Powered Sensor Nodes
Abstract:
Solar-powered sensor nodes (SCSNs) with energy storages have the greatest potential and are widely used in the coming era of the Internet of Things, since they avoid tedious battery maintenance tasks. However, because the solar energy source is unstable and limited, the sensor nodes suffer from high deadline miss ratio (DMR). To achieve better DMR, the existing scheduling algorithms find the best scheduling scheme in a single period of the recurring task queue and, hence, ignore the long-term performance. To tackle this challenge, this paper proposes a three-level dynamic voltage–frequency scaling (DVFS)-based scheduling strategy to minimize long-term DMR for dual-channel SCSNs. This approach includes a day-level scheduler to achieve a coarse-grained task arrangement, two artificial neural networks to determine the task priorities, and a DVFS-based task selection algorithm for slot-level execution. Experiments show that the proposed scheduler reduces DMR by over 30% on average.
Autors: Tongda Wu;Yongpan Liu;Daming Zhang;Jinyang Li;Xiaobo Sharon Hu;Chun Jason Xue;Huazhong Yang;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 2981 - 2994
Publisher: IEEE
 
» Dynamic Analysis of High-Speed Three-Degree-of-Freedom Electromagnetic Actuator for Image Stabilization
Abstract:
Recently, a high-quality image has been obtained by a video camera because of its improved imaging performance. However, image quality deteriorations due to vibration have become a problem. In order to solve this problem, various image stabilization technologies have been developed. A lens-unit-swing system which consists of a lens and an imaging device is one of the image stabilization technologies that generate an inverse motion and correct images from camera shakes over a wide range of rotation angles around three axes. However, the lens-unit-swing system has some problems such as an increase in size and weight. On the other hand, recently, various multiple-degree-of-freedom (DOF) actuators have been developed. These actuators are expected to simplify the system. In this paper, we propose a high-speed three-DOF electromagnetic actuator for image stabilization which can be controlled by a simple control system. The basic structure and operating principle of the actuator are described. Moreover, the frequency characteristics are calculated by the transfer function and 3-D finite-element method. In addition, the dynamic characteristics under the position feedback control are analyzed and the effectiveness of the actuator is verified.
Autors: Akira Heya;Katsuhiro Hirata;Noboru Niguchi;Takamichi Yoshimoto;Tomohiro Ota;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Dynamic Capability and Firm Performance: The Role of Marketing Capability and Operations Capability
Abstract:
Scholars have argued that dynamic capability can influence firm performance through a variety of means and mechanisms. However, the empirical test of the relationship between dynamic capability, marketing capability, and operations capability on firm performance has remained scant. We contribute to resolving this issue by proposing a research model that links dynamic capability with marketing and operations capabilities on new product development performance specifically and firm performance generally. First, the model suggests that marketing capability and operations capability act as mediating mechanisms that transmit the positive influences of dynamic capability to new product development performance specifically and firm performance generally. Second, the model proposes the relationship between marketing capability, operations capability, and firm performance (new product development performance) be stronger if firms have adequate dynamic capability. Drawing on a dataset of multiyear longitudinal survey data of Chinese high-tech firms, we find support for the proposed model. The findings help us better explain the different ways in which dynamic capability affect performance.
Autors: Jifeng Mu;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Nov 2017, volume: 64, issue:4, pages: 554 - 565
Publisher: IEEE
 
» Dynamic Control Allocation for Damping of Inter-Area Oscillations
Abstract:
Use of actuator redundancy to achieve higher reliability is a widely accepted engineering design technique and is used in this study to build resiliency and ensure power system stability in the presence of high levels of renewables. This paper presents a new design method for fault-tolerant wide-area damping controllers (WADCs) using modal-based control allocation (MB-CA), which coordinates a set of actuators to contribute to damping of inter-area oscillations. In our proposed method, when an actuator fails or is unavailable (e.g., due to communication failure), the supervisory MB-CA distributes the control signals to the remaining healthy actuators based on effects on the modal system, desired control actions, and actuator constraints. Our proposed block offers the benefits of modular design where it is independent of the nominal WADC. The proposed method consists of mainly two design steps. The first step is to design a WADC based on a fault-free model using robust control methods. The second step is to design an MB-CA to manage actuator availability and constraints. To validate the feasibility and demonstrate the design principles, a set of comprehensive case studies are conducted on a modified 192-bus Western Electricity Coordinating Council system. Numerical results verify the effectiveness of the proposed approach in ensuring resiliency to different actuator failures and actuator availability.
Autors: M. Ehsan Raoufat;Kevin Tomsovic;Seddik M. Djouadi;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4894 - 4903
Publisher: IEEE
 
» Dynamic Magnetization Properties of Platelet Ferromagnetic Nanoparticles and Their Heat Generation Injected in Tumors of Mice
Abstract:
Development of high-heat-generating materials is essential for magnetic nanoparticle hyperthermia therapy. As a candidate, oval platelet Fe oxide nanoparticles of sizes 30–100 nm were synthesized, and their surfaces were decorated with tetraethylene glycol block polymer. The water-based suspension showed good dispersion properties, suggesting high applicability for medical usage. High-frequency hysteresis measurement, which is helpful for understanding the mechanism of specific loss power, was carried out at the same frequency and magnetic field amplitude () range as heating. Frequency-independent ferromagnetic hysteresis was observed, and this supported the ferromagnetic heating mechanism. The suspension was directly injected into the cancerous tumor of mice and subjected to 114 kHz alternating current magnetic field below 51 kA/m, which was sufficient for elevating the local temperature to approximately 50 °C. The tumor size decreased upon heating at an early stage and was restored to nearly the original size after 14 days. Distinguished differences were observed between the platelet Fe and superparamagnetic particles with respect to temperature rise and the resulting damaging effects to the tumor.
Autors: Eiji Kita;Hideto Yanagihara;Mikio Kishimoto;Kouji Ota;Ryoichi Miyamoto;Tatsuya Oda;Nobuhiro Ohkohchi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Dynamic Phasor Estimation Through DSTKF Under Transient Conditions
Abstract:
This paper presents a double suboptimal-scaling-factor adaptive strong tracking Kalman filter (DSTKF)-based phasor measurement unit algorithm which can meet the accuracy requirement of the IEEE standard C37.118.1 under the dynamic condition. This method uses a kth Taylor polynomial to linearize the complex exponential of the signal model, and estimates the dynamic phasor using DSTKF. The antialias filter unit for DSTKF algorithm is included to suppress high-order harmonics which will augment computing burden. By applying double suboptimal-scaling factors, DSTKF adjusts the process noise covariance matrix and the prediction covariance matrix in real time. Thereafter, amplitude and frequency measurement performances under various dynamic conditions are assessed in detail. Theoretical analysis and comprehensive experimental results validate the effectiveness of the proposed method.
Autors: Chun Huang;Xing Xie;Hui Jiang;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 2929 - 2936
Publisher: IEEE
 
» Dynamic Resizing on Active Warps Scheduler to Hide Operation Stalls on GPUs
Abstract:
This paper conducts a detailed study of the factors affecting the operation stalls in terms of the fetch group size on the warp scheduler of GPUs. Throughout this paper, we reveal that the size of a fetch group is highly involved for hiding various types of operation stalls: short latency stalls, long latency stalls, and Load/Store Unit (LSU) stalls. The scheduler with a small fetch group cannot hide short latency stalls due to the limited number of warps in a fetch group. In contrast, the scheduler with a large fetch group cannot hide long latency and LSU stalls due to the limited number of fetch groups and the lack of memory subsystems, respectively. To hide various types of stalls, this paper proposes a Dynamic Resizing on Active Warps (DRAW) scheduler which adjusts the size of a fetch group dynamically based on the execution phases of applications. For the applications that have the best performance at LRR (one fetch group), the DRAW scheduler matches the performance of LRR and outperforms TL (multiple fetch groups) by 22.7 percent. In addition, for the applications that have the best performance at TL, our scheduler achieves 11.0 and 5.5 percent better performance compared to LRR and TL, respectively.
Autors: Myung Kuk Yoon;Yunho Oh;Seung Hun Kim;Sangpil Lee;Deokho Kim;Won Woo Ro;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3142 - 3156
Publisher: IEEE
 
» Dynamic State Aware Adaptive Source Coding for Networked Control in Cyberphysical Systems
Abstract:
A source coding (quantization) scheme is studied for the feedback of discrete-time and continuous-state cyber-physical systems (CPSs). It is formulated as a sequential coding optimization problem. The goal is to find a deterministic but adaptive policy, as a series of mappings from the historical information to the quantization strategy. In particular, an optimization problem is formulated, and then solved by the Bellman equation in dynamic programming (DP). To overcome the challenge of continuous state space, a practical solution is proposed by leveraging the approximate DP (ADP). The performance of the proposed strategy is examined for both scalar and vector dynamical systems in two practical applications. It shows that the designed policy can significantly outperform the simple fixed quantization strategies in CPSs and can be applied to the mobile/vehicle communication.
Autors: Liang Li;Ju Bin Song;Husheng Li;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10000 - 10010
Publisher: IEEE
 
» Dynamically Adaptable Software Is All about Modeling Contextual Variability and Avoiding Failures
Abstract:
Contextual-variability modeling is integral to dealing with dynamically adaptable software. Several techniques support this task using dynamic-software-product-line engineering, which enables runtime management of software variants. In particular, context-aware feature modeling (CFM) has been considered suitable for dealing with contextual variability. However, it has limited expressiveness to specify real-world constraints related to context information. To tackle this limitation, this article proposes eCFM, an extended form of CFM. In addition, it presents an approach using eCFM and model checking to identify common design faults that could lead to runtime failures. A comparison of CFM and eCFM showed that eCFM was more expressive and easier to use.
Autors: Ismayle de Sousa Santos;Magno Luã de Jesus Souza;Michelle Larissa Luciano Carvalho;Thalisson Alves Oliveira;Eduardo Santana de Almeida;Rossana Maria de Castro Andrade;
Appeared in: IEEE Software
Publication date: Nov 2017, volume: 34, issue:6, pages: 72 - 77
Publisher: IEEE
 
» Dynamics of Laser-Induced Magnetostructural Phase Transitions in MnAs/GaAs (001) Epitaxial Layers
Abstract:
We have investigated by time-resolved X-ray diffraction the manganese arsenide structure dynamics in MnAs/GaAs (001) epitaxial films, when the magnetostructural phase transition is triggered by an ultra-fast optical laser pulse. Understanding the photo-induced phase transition dynamics is relevant for applications of MnAs/GaAs (001) as a magnetically active template in laser-induced magnetization switching processes. The main goal of our experiment is to determine the timescales of the structural changes that are likely to play a role in laser-driven magnetization reversal.
Autors: Lounès Lounis;Yunlin Zheng;Carlo Spezzani;Eugenio Ferrari;Mahmoud Edrrief;Alessandra Ciavardini;Horia Popescu;Enrico Allaria;Claire Laulhé;Franck Vidal;Maurizio Sacchi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Early Fault Diagnosis of Rotating Machinery by Combining Differential Rational Spline-Based LMD and K–L Divergence
Abstract:
First, an improved local mean decomposition (LMD) method called differential rational spline-based LMD (DRS) is developed for signal decomposition. Differential and integral operations are introduced in LMD, which can weaken the mode mixing problem. Meanwhile, an optimized rational spline interpolation is proposed to calculate the envelope functions aiming to reduce the large errors caused by moving average in the traditional LMD. A series of product functions (PFs) is obtained after the application of the proposed DRS-LMD. Then, Kullback-Leibler (K-L) divergence is adopted to select main PF components that contain most fault information. The machine fault can be easily identified from the amplitude spectrum of the selected PF component. The effectiveness of the proposed DRS-LMD and K-L strategy is tested on simulated vibration signals and experimental vibration signals. Results show that the proposed method can increase the decomposition accuracy of the signals and can be used to detect early faults on the gears and rolling bearings.
Autors: Yongbo Li;Xihui Liang;Yuantao Yang;Minqiang Xu;Wenhu Huang;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Nov 2017, volume: 66, issue:11, pages: 3077 - 3090
Publisher: IEEE
 
» Economic, Environmental, and Social Impact of Remanufacturing in a Competitive Setting
Abstract:
This paper studies the environmental and social trade-offs of remanufacturing for product+service firms under competition. We use an analytical model and a behavioral study that together incorporate demand cannibalization from multiple customer segments across the competing firms’ product lines. We measure firms’ profits, consumer surpluses, environmental impacts, and environmental costs along the products lifecycles in the resultant equilibria with and without remanufacturing. We show that competition intensifies the tension between increased profit and worsened environmental impact from market expansions caused by remanufacturing identified by prior research in the case of monopoly. However, bringing in the social dimension leads to an overall positive assessment: remanufacturing creates additional consumer surplus, which compensates for the cost of the environmental impact. In other words, we found strong support that remanufacturing is beneficial for the society.
Autors: Gal Raz;Anton Ovchinnikov;Vered Blass;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Nov 2017, volume: 64, issue:4, pages: 476 - 490
Publisher: IEEE
 
» Eddy Current Brake With a Two-Layer Structure: Calculation and Characterization of Braking Performance
Abstract:
This paper presents a new method for calculating the braking force of a drum-type eddy current brake with a two-layer structure. The drum-type eddy current brake should have a structure that improves the braking force by applying a material with high conductivity inside the drum because the eddy current loss generated from the drum is used as the braking force. In addition, because the eddy current brake operates at various speeds while braking the vehicle, it is necessary to grasp the braking force according to the speed. Furthermore, because the material of the drum is composed of non-laminated iron having conductivity, the skin effect and the armature reaction phenomenon appear, and the skin depth and the air-gap flux density are different depending on the braking speed. In this paper, the value of the eddy current loss of the eddy current brake with a copper coating inside the drum is newly presented and compared with the finite-element analysis results. In addition, the change in the speed–torque curve according to the conductivity value of the drum and inner coating material are shown. Finally, an experiment was conducted to compare and verify the characteristic curve of the eddy current brake obtained from the newly derived equations.
Autors: Sooyoung Cho;Huai-Cong Liu;Hanwoong Ahn;Ju Lee;Hyung-Woo Lee;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Eddy Current Non-Destructive Evaluation for Healthiness of Radiator Structure
Abstract:
This paper presents a non-destructive evaluation study on a radiator with cooling fins as a kind of complex shaped specimen. An eddy current testing method, namely multi-frequency excitation and spectrogram method, was employed to detect a removal of radiator cooling fin. Experimental results brought remarkable signal when a fin was removed. Furthermore, the authors discuss the relation between the fin signal and specimen thickness, and concludes the availability for the estimation of thickness of radiator structures.
Autors: Shoichiro Nagata;Masaaki Numachi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Editor's Note
Abstract:
Autors: Elisa Bertino;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Nov 2017, volume: 14, issue:6, pages: 577 - 577
Publisher: IEEE
 
» Editorial
Abstract:
In February 2017 Science magazine reported widespread concern among US graduate programs in engineering over the "sharp drop this year in the number of applications from international students." The cause of the observed drop was suspected to be the anti-immigrant rhetoric of President Donald Trump during his campaign and election. The Council of Graduate Schools is still in the process of compiling final statistics on international applications for 2017, but this potential recruiting crisis has prompted me to reflect upon the highly intricate nature of graduate education in the United States, from my perspective.
Autors: Nicola Bowler;
Appeared in: IEEE Electrical Insulation Magazine
Publication date: Nov 2017, volume: 33, issue:6, pages: 4 - 5
Publisher: IEEE
 
» Editorial 2016 Best Paper Award
Abstract:
High quality scholarship requires technical excellence but also connects the work to the primary references in the field. In this way the reader advances their knowledge and gains perspective. The Transactions on Semiconductor Manufacturing supports these goals by recognizing the best paper chosen by the Associate Editors and reviewers. The winning paper was selected from 51 papers published by TSM in 2016. The winner is “Risk-Controlled Product Mix Planning in Semiconductor Manufacturing Using Simulation Optimization” by Dr. Kuo-Hao Chang published in the November 2016 issue of IEEE Transactions on Semiconductor Manufacturing (10.1109/TSM.2016.2602388). Dr. Chang is a professor of Industrial Engineering and Engineering Manufacturing at National Tsing Hua University in Hsinchu, Taiwan. The paper applies a method developed in another domain to find the optimal product mix in a semiconductor manufacturing line. On behalf of the associate editors, I congratulate Dr. Chang on being selected.
Autors: Anthony J. Muscat;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 314 - 314
Publisher: IEEE
 
» Editorial for November 2017 Issue
Abstract:
This issue of the IEEE Transactions on Engineering Management includes 15 research articles. The relevance and usefulness of the articles is summarized. In addition, various Society-related matters are announced.
Autors: Rajiv Sabherwal;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Nov 2017, volume: 64, issue:4, pages: 433 - 436
Publisher: IEEE
 
» Editorial Kudos to Our Reviewers
Abstract:
The people that we depend on to review the manuscripts published in the Transactions on Semiconductor Manufacturing ensure that work of the highest quality ends up in each finished paper. Often this requires multiple detailed readings of a manuscript separated by several weeks from one another. The reviewers are all recognized experts in their fields. Despite the demands to fulfill the duties of their employers they set aside time to support the broad dissemination of the latest results on factory and manufacturing integration, process control, yield enhancement and modeling, metrology, photolithography, factory modeling and control, and equipment technology—all of the areas that go into a modern semiconductor manufacturing facility. I personally thank all of the contributions that our reviewers have made in 2017. We would not have a journal that is a leading source of information on semiconductor manufacturing without this selfless effort.
Autors: Anthony J. Muscat;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 313 - 313
Publisher: IEEE
 
» EEG-Based User Reaction Time Estimation Using Riemannian Geometry Features
Abstract:
Riemannian geometry has been successfully used in many brain–computer interface (BCI) classification problems and demonstrated superior performance. In this paper, for the first time, it is applied to BCI regression problems, an important category of BCI applications. More specifically, we propose a new feature extraction approach for electroencephalogram (EEG)-based BCI regression problems: a spatial filter is first used to increase the signal quality of the EEG trials and also to reduce the dimensionality of the covariance matrices, and then Riemannian tangent space features are extracted. We validate the performance of the proposed approach in reaction time estimation from EEG signals measured in a large-scale sustained-attention psychomotor vigilance task, and show that compared with the traditional powerband features, the tangent space features can reduce the root mean square estimation error by 4.30%–8.30%, and increase the estimation correlation coefficient by 6.59%–11.13%.
Autors: Dongrui Wu;Brent J. Lance;Vernon J. Lawhern;Stephen Gordon;Tzyy-Ping Jung;Chin-Teng Lin;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2157 - 2168
Publisher: IEEE
 
» Effect of a Platinum Buffer Layer on the Magnetization Dynamics of Sputter Deposited YIG Polycrystalline Thin Films
Abstract:
The present investigation deals with the effect of thickness and a platinum (Pt) buffer layer on the dynamic magnetic properties of polycrystalline yttrium iron garnet (YIG) films fabricated after post-annealing to recrystallize from the amorphous state. The dynamic magnetic properties of films without a buffer layer deteriorate as the thickness decreases as indicated by the increased line-widths in the ferromagnetic resonance spectra. On the other hand, a strong rejuvenation in the static and dynamic magnetic properties of the films is observed when a Pt buffer layer is used. The Pt buffer layer decreases the Gilbert damping parameter from and for a 100 nm-thick YIG film. These observations mainly originate from controlling the microstructure or the surface morphology of the films.
Autors: Satya Prakash Pati;Muftah Al-Mahdawi;Yohei Shiokawa;Masashi Sahashi;Yasushi Endo;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Effect of Ammonium Chloride in Plating Baths on Soft Magnetic Properties of Electroplated Fe–Ni Films
Abstract:
We electroplated Fe–Ni films in plating baths with ammonium chloride (NH4Cl) and evaluated the magnetic properties of the films. The amount of NH4Cl did not affect the current efficiency of the plating process and the Fe content in the film. The obtained current efficiency of approximately 95% is much higher than our previous study. The coercivity dramatically decreased with increasing NH4Cl from 0 to 15 g/L, and we obtained Fe22Ni78 films with very low coercivity (10 A/m). The Cl concentration in the plating bath affected the coercivity, and we found that a plating bath with moderate low concentration of Cl is preferred for obtaining the Fe22Ni78 films with low coercivity.
Autors: T. Yanai;K. Koda;K. Eguchi;K. Takashima;T. Morimura;M. Nakano;H. Fukunaga;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 3
Publisher: IEEE
 
» Effect of Amorphous/Crystalline Material Doping on the Microstructure and Magnetic Properties of FePt Thin Films
Abstract:
The effects of various doping materials (amorphous phases: TiO2, SiO2, MgO, and C and crystalline phases: HfO2 and ZrO2) on the microstructure and magnetic properties of FePt thin films have been investigated. It is found that FePt films with amorphous doping materials especially MgO and C have better (001) texture and grain isolation than doping with crystalline materials. Nevertheless, doping with crystalline materials, FePt films were preferred to form columnar structures with a larger aspect ratio compared with semi-spherical grain shape for amorphous doping materials. Moreover, all the FePt-X films exhibit better perpendicular anisotropy except for FePt-ZrO2 films due to some FePt (200) textured films epitaxial grown directly on tetragonal (002) textured ZrO2. For crystalline materials doping, the (001) texture and perpendicular anisotropy could be improved by tuning crystalline oxide materials with appropriate lattice structure, which may offer a method for application in FePt in heat-assisted magnetic recording media.
Autors: K. F. Dong;F. Jin;W. Q. Mo;J. L. Song;W. M. Cheng;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effect of Annealing on Domain Wall Mass in Amorphous FeCoMoB Microwires
Abstract:
The effect of annealing on the domain wall mass in amorphous FeCoMoB microwires has been studied. Annealing at 300 °C for 1 h leads to the relaxation of strong stresses from production process and to the homogenization of its amorphous structure. As a result of such annealing, the domain wall mass decreases from kg in the as-cast state to kg in the annealed state, while the thickness of the domain wall exhibits opposite tendency and increases from 493 nm in the as-cast state to 808 nm in the annealed sample.
Autors: P. Klein;J. Onufer;J. Ziman;G. A. Badini-Confalonieri;M. Vazquez;R. Varga;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effect of Arbitrary Shear Stress on Vector Magnetic Properties of Non-Oriented Electrical Steel Sheets
Abstract:
The magnetic properties of electrical steel sheets, which are used as core materials in numerous electric-powered machines, tend to deteriorate due to residual stress and external loads during manufacturing processes. Previously, we reported our measurement results for the residual stress distribution in a motor core and clarified that sheer stress, along with tensile and compressive stress, exists in the core’s plate and surface, which makes it necessary to evaluate the magnetic properties of the core material under various stress conditions. In this paper, we report the results of an investigation into the effects of an arbitrary shear stress on the vector magnetic properties of a non-oriented electrical steel sheet under both alternating and rotating conditions.
Autors: Yuichiro Kai;Masato Enokizono;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effect of Buffer Layer Annealing on the Growth of (001)-Textured MnGa Ultrathin Films With Perpendicular Magnetic Anisotropy
Abstract:
The effect of buffer layer annealing on the growth of (001)-textured 3 nm thick MnGa films with perpendicular magnetic anisotropy (PMA) was investigated. The film stacking of Si/SiO2 substrate/MgO/Cr/CoGa/MnGa was fabricated by magnetron sputtering. It was found that the CoGa buffer layer crystallized with a (001) orientation and B2 chemical ordering even without any thermal treatments. Interestingly, the 3 nm thick MnGa grown on the un-annealed CoGa buffer layer showed PMA, indicating that the CoGa buffer layer promoted the growth of (001)-textured MnGa films with chemical ordering even without the annealing process. Annealing the CoGa buffer layer above 400 °C improved the (001) orientation of the CoGa buffer and MnGa layers. The effective PMA constant was about 4 Merg/cm3 without the annealing and was slightly reduced with increasing the annealing temperature, whereas the PMA dispersion was improved by the annealing. These results can help to obtain (001)-oriented MnGa ultrathin films with high PMA.
Autors: Kazuya Z. Suzuki;Atsuo Ono;Reza Ranjbar;Atsushi Sugihara;Shigemi Mizukami;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effect of Carbon Addition on Magnetic Order in Mn–Al–C Alloys
Abstract:
The near-equiatomic Mn–Al alloys are considered for possible applications as rare-earth-free permanent magnets due to the existence of a ferromagnetic -phase with crystal structure and other attractive physical properties. However, this tetragonal phase is metastable and can only be obtained from a hexagonal -phase enriched in manganese. The partial atomic disorder can results in antiferromagnetic coupling of the Mn atoms occupying different sublattices. Moreover, the carbon addition, used to improve phase stability and coercivity, leads to the deformation of the unit cell and can affect the Mn–Mn coupling. To clarify this question, a series of magnetic measurements and neutron diffraction (ND) experiments in a wide temperature range was carried out on the Mn55Al45 alloys doped with a small quantity of C. The materials were prepared by melt-spinning and subsequent annealing. Different methods of carbon introduction were tried, the best results were obtained by melting Mn and Al with Mn23C6. The structural and magnetic properties of the ferromagnetic and paramagnetic -phase as well as the precursor -phase were determined. The average magnetic moments on two sublattices were analyzed using the Weiss plot of the magnetometric data and the Rietveld refinement of the ND data. The dependence of the magnetic moments on the C content and temperature is reported. Ferrimagnetic behavior of the Mn–Al alloys with excess of manganese, caused by antiferromagnetic couplin- and responsible for the decrease of magnetization with increase of Mn content, was confirmed.
Autors: Muriel Tyrman;Alexandre Pasko;Loïc Perrière;Victor Etgens;Olivier Isnard;Frédéric Mazaleyrat;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Effect of Film Thickness on the High Frequency Magnetic Properties of Polycrystalline Fe–Ga Films
Abstract:
This paper describes the effect of film thickness on the high frequency magnetic properties of polycrystalline Fe–Ga films. The damping constant ( increases markedly from approximately 0.015 to 0.081 for a film thickness below 20 nm, reaches a maximum value of 0.084 at a thickness of 30 nm, and then decreases to 0.068 as the thickness further increases to 100 nm. All the values are much larger than those of a single crystal Fe–Ga film, indicating that the extrinsic damping overlaps with the intrinsic damping. The inhomogeneous broadening in a zero field [(0)] significantly increases with the film thickness due to the magnetic inhomogeneities, such as anisotropy dispersion and other effects. In addition, increases markedly as the saturation magnetostriction ( increases. This behavior is very similar to those of Ni–Fe and Ni–Fe–M films. Therefore, these results demonstrate that is correlated with regardless of the film thickness, and also sensitive to magnetic inhomogeneities.
Autors: Yasushi Endo;Takumi Sakai;Takamichi Miyazaki;Yutaka Shimada;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Effect of Finite Tunneling Magnetoresistance for the Switching Dynamics in the Spin Transfer Torque Magnetic Tunneling Junctions
Abstract:
We investigate the effect of tunneling magnetoresistance (TMR) on the spin transfer-torque (STT) switching behaviors in magnetic tunneling junctions. In most of the micromagnetic simulations for STT switching, a uniform current density has been assumed, which is not realistic in the high TMR devices. The local STT is proportional to the local current density, and the local current density will be determined by the local resistivity. Since higher than 150% of TMR values is required in the real STT-magnetoresistive random access memory devices, the local resistance is dramatically changed as a function of the relative spin orientation between the fixed and free layers under the constant voltage operation mode. By employing non-uniform current density in STT switching simulations using the “embedded object-oriented micromagnetic framework” scheme, we found that the details of switching behaviors such as switching time and critical current density are significantly influenced by the TMR values.
Autors: Chun-Yeol You;Hyungsuk Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effect of Interface Trap Charges on Performance Variation of Heterogeneous Gate Dielectric Junctionless-TFET
Abstract:
In this paper, we investigate the effect of interface trap charges on the variation of heterogeneous gate dielectric junctionless-tunnel FET (JL-TFET) by introducing both donor and acceptor type of localized charges at the semiconductor/insulator interface. In this regard, we have analyzed dc and analog/RF performance parameters for conventional and heterogeneous gate dielectric JL-TFET (HD JL-TFET) in terms of electric field, transfer characteristics, transconductance (), output transconductance (), parasitic capacitances, device efficiency, cutoff frequency (), gain bandwidth product, and transconductance frequency product. Apart from these, linearity distortion parameters are also analyzed in the form of higher order transconductance coefficients (, , ), VIP2, VIP3, IMD3, and IIP3. For this, high-K gate dielectric material (HfO2) is used in the case of the HD JL-TFET to improve the performance of the device. All the simulations for both devices have been performed with the help of an ATLAS device simulator.
Autors: Sarthak Gupta;Kaushal Nigam;Sunil Pandey;Dheeraj Sharma;Pravin N. Kondekar;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4731 - 4737
Publisher: IEEE
 
» Effect of Magnetic Ordering on the Stability of Ni–Mn–Ga(–Co–Cu) Alloys Along the Tetragonal Deformation Path
Abstract:
The influence of magnetic ordering on the stability of Ni–Mn–Ga(–Co–Cu) Heusler alloys is investigated using the first-principles exact muffin-tin orbital method in combination with the coherent-potential approximation. The paramagnetic (PM) state is described by disordered local moment approach. In stoichiometric Ni2MnGa alloy, the total energy profile along the tetragonal deformation path differs between ferromagnetic (FM) ground state and PM state with high energy, where cubic structure of austenite exhibits lower total energy than tetragonally distorted structure of martensite. Martensitic structure is stabilized in ground state by FM interaction. In PM state it can be stabilized by partial substitution of Ni by Co or by partial substitution of Mn/Ga by Cu. Energy difference between PM and FM state can be used for qualitative estimation of Curie temperature . Since Co doping to Ni sublattice slightly increases , the should also increase, which corresponds to experimental findings. Analogically, Cu doping to Mn sublattice strongly decreases , which corresponds to strong decrease of , also confirmed experimentally. For Cu doping in Ga sublattice the decrease in is weaker.
Autors: Martin Zelený;Alexei Sozinov;Torbjörn Björkman;Ladislav Straka;Oleg Heczko;Risto M. Nieminen;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Effect of Nanogap-Based Light-Matter Colocalization on the Surface Plasmon Resonance Detection
Abstract:
A nanoscale gap aperture has been used as a fundamental tool for diverse applications. In this paper, we investigate the effect of nanogap aperture parameters on optical sensors, primarily based on surface plasmon resonance. A simple 2-D model was used for DNA immobilization and hybridization, in which nanogap enables light-matter colocalization to amplify detection signatures, thereby enhancing performance characteristics. Interestingly, the optimum gap geometry that produces maximum light-matter overlap and the largest resonance shift was not associated with the smallest gap size. Highest sensitivity was observed to correlate with negative resonance shift due to increased damping as well as the excitation of higher order surface plasmon polariton modes. Zero-shift nanogap was also discussed. The results suggest that careful design of nanogap apertures should be carried out to make the most of what they can achieve.
Autors: Changhun Lee;Eunji Sim;Donghyun Kim;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4721 - 4727
Publisher: IEEE
 
» Effect of Particle Shape, Density, and Inhomogeneity on the Microwave Optical Properties of Graupel and Hailstones
Abstract:
Atmospheric ice particles can be rimed and contaminated (e.g., by soot attachments). Previous optical property calculations usually assume rimed particles such as graupel and hailstones to be homogeneous spheres with fixed densities. The relevant dielectric constants are estimated with the effective medium approximation (EMA), although such particles are predominately nonspherical, porous, and contain small interior grains. This paper assesses the effects of nonsphericity, density, and inhomogeneity of graupel and hailstones on their optical properties. The bicontinuous medium approximation (BMA) is employed to simulate the particle internal structure. Conical shapes are compared with spherical and spheroidal shapes to assess the effect of nonsphericity. At frequencies lower than 89 GHz, the optical properties are more sensitive to particle’s mass density than to overall particle shape, and the internal structure plays an insignificant role when the particle effective diameter (a quantity involving the particle size distribution) is smaller than approximately 10 mm, and the internal grain size is smaller than 0.2 mm. With a small grain size, the BMA phase function converges to the EMA phase function with an effective refractive index calculated with the Bruggeman formulation. Simulated top of atmosphere radiances at three microwave frequencies, 18.7, 36.5, and 89 GHz, are quite sensitive to ice particle effective diameter between 1 and 5 mm, ice fraction between 0.1 and 0.9, and ice water path between 1 and 5 kg/. Thus, these frequencies are suitable for retrieving the microphysical properties.
Autors: Guanglin Tang;Ping Yang;Patrick G. Stegmann;R. Lee Panetta;Leung Tsang;Benjamin Johnson;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6366 - 6378
Publisher: IEEE
 
» Effect of Pole–Slot Combination on Eddy-Current Formation in PMSM Rotor Assembly Including Retaining Plate Structure
Abstract:
The results of the 3-D finite-element method electromagnetic analysis of the constant speed variable output permanent magnet synchronous motor including the rotor retaining plate structure confirmed that the eddy current flow was induced in the rotor part. Eddy current flows from the permanent magnet to the rotor retaining plate, and it was found that there is induced voltage that generates eddy currents in the retaining plate from the aspect of eddy-current distribution. The eddy current flow from the permanent magnet to the retaining plate is related to the change in magnetic resistance during rotation and is also related to the effect of slot harmonics on the air-gap magnetic flux density. In this paper, the characteristics of the eddy current flow in the rotor assembly were investigated when the retaining plate is included for various slot combinations. The eddy-current generation according to the slot combination is analyzed and the cause of such tendency was investigated. Furthermore, from the pattern of eddy-current formation, it was noted that the aperiodic pole–slot combination models may have a larger eddy-current loss increase when combined with the retaining plate.
Autors: Hyun-Woo Jun;Hyun-Soo Seol;Ju Lee;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Effect of Rotor Geometry on Peak and Average Torque of External-Rotor Synchronous Reluctance Motor in Comparison With Switched Reluctance Motor for Low-Speed Direct-Drive Domestic Application
Abstract:
This paper deals with the feasibility of developing an external-rotor synchronous reluctance motor for a low-speed direct-drive domestic application. Here, an attempt is made to identify the rotor geometry which provides high peak, average torque, and the saliency ratio in comparison with those of equivalent external-rotor switched reluctance motor (Ex-R SRM) which has already been developed and tested for the same application. In this context, six different rotor geometries are considered for the feasibility study and their performance characteristics are predicted using finite-element analysis. These results are compared with the equivalent size of Ex-R SRM, and finally, a feasible rotor geometry is proposed for further investigation and for the prototype designing.
Autors: M. Azhagar Raj;A. Kavitha;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 8
Publisher: IEEE
 
» Effect of Stress on Magnetic Properties of Annealed Glass-Coated Co71Fe5B11Si10Cr3 Amorphous Microwires
Abstract:
Various thermal treatments have long been known to be effective in tailoring structural and magnetic properties of amorphous ferromagnetic wires, consequently, a desired magnetic anisotropy can be controlled for specific sensing applications. This paper deals with the effects of annealing and applied stresses on the magnetization processes and magnetoimpedance (MI) in Co71Fe5B11Si10Cr3 glass-coated microwires having amorphous or partially crystalline structure. The alloy under study has a small positive magnetostriction (approximately ) in its amorphous unstressed state. By applying a tensile stress to amorphous microwires, an abrupt transformation of the hysteresis loop is observed owing to the anisotropy type change due to stress-dependent magnetostriction which changes sign. The modification in the anisotropy type greatly enhances the stress sensitivity of higher frequency harmonics induced during re-magnetization and MI. The wires with a partially crystalline structure did not exhibit a noticeable stress dependence of magnetic properties, but after annealing a significant increase in coercivity was observed after applying a tensile stress. The obtained results were investigated in terms of a magnetostrictive model of magnetic anisotropy offering a reasonable explanation.
Autors: M. G. Nematov;M. M. Salem;A. M. Adam;M. Ahmad;N. A. Yudanov;L. V. Panina;A. T. Morchenko;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Effect of Temperature in Hysteretic Synchronization of Magnetic Vortex Spin-Torque Nano-Oscillators
Abstract:
The synchronization of vortex spin-transfer nano-oscillators (both nanopillar and nanocontact structures) with external microwave excitations is considered. A collective variables description is used to derive an analytical reduced-order model for the vortex core dynamics, which is able to predict all the possible oscillation regimes and hysteretic transitions among them. The influence of thermal fluctuations on hysteretic synchronization is studied by full micromagnetic simulations. The numerical results are in good agreement with the theory.
Autors: M. d’Aquino;S. Perna;A. Quercia;V. Scalera;C. Serpico;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Effect of Transcranial Magnetic Stimulation of Acupuncture Point on Brain Network
Abstract:
Transcranial magnetic stimulation (TMS), as a new therapy, has been proven to be efficient in inducing electric fields in the neuronal tissues and modulating brain activity in the applications to stimulate different positions of human body such as the brain, peripheral nerves, and acupuncture points (acupoint) in the last decade. Acupuncture, an ancient therapeutic technique, is gaining popularity in Western medicine, but the underlying regulation mechanism of acupuncture has not been well understood and still needs to be further investigated. By using electroencephalogram, signals before and following stimulation of Shenmen acupoint (HT7) were acquired noninvasively. Then, we adopted a network model analysis from graph theory to construct a network and evaluate network measures of brain connectivity among multiple brain regions before and following stimulation. An analysis of the resulting brain functional network found that the parietal lobe and parietal-occipital lobe shared lower degree and strength following stimulation than before and the frontal lobe shared higher betweenness centrality than before. The network measures with significant differences were distributed over the brain areas contralateral to the stimulated hand, which has probable association with the regulation mechanism of TMS of HT7 acupoint.
Autors: Lingdi Fu;Guizhi Xu;Hongli Yu;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effect of Transcranial Magnetic Stimulation on Demyelinated Neuron Populations
Abstract:
Transcranial magnetic stimulation (TMS) is non-invasive neuromodulation therapy which uses time-varying magnetic fields to induce electric fields within the patient’s brain, thus allowing for neural stimulation of the targeted region. While past studies have used finite-element analysis (FEA) to model the effects of stimulation on brain tissue, there have been limited studies which analyze the effects of the same stimulation on the neuron responses. We use a python package called NEST to model the populations of neurons which are healthy as well as those that have diminished or absent myelin sheath. We model diminished myelin sheath by increasing the capacitance of the neuron. We study the effects of TMS on the synaptic activity of these populations by utilizing clinical parameters specific to TMS. Furthermore, we compare our results to the models of brain tissue stimulation using the FEA software Sim4Life. Our results indicate that all neuron populations, regardless of their myelination state, retain some stimulation threshold which increases discretely as the myelin sheath diminishes. Using tissue analysis, we also computed the range of TMS current necessary to reach these stimulation thresholds for demyelinated populations. Furthermore, we find that the maximum-induced E-field on the cortical surface does not exceed 220 V/m for stimulation of highly demyelinated neuron populations. Therefore our study finds that although demyelinated neurons exhibit much lower nominal synaptic activity than healthy neurons, they are nevertheless responsive to TMS, and these stimulation thresholds can be reached without inducing an unsafe maximum E-field on the cortex.
Autors: F. Syeda;A. Pandurangi;A. A. El-Gendy;R. L. Hadimani;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effect of Underlying Bi2Se3 Surface on Magnetic Properties of Ni Films
Abstract:
We have investigated magnetic properties of Ni film specimens deposited either on GaAs or on Bi2Se3 surfaces. The magnetization saturation field along the out-of-plane direction observed in the Hall data was weaker for the Ni/Bi2Se3 sample than for the Ni/GaAs sample. On the other hand, planar Hall resistance measurements showed the larger in-plane coercive field for Ni/Bi2Se3 than for Ni/GaAs. These changes of magnetic hardness observed along the out-of-plane and in-plane directions in the Ni/Bi2Se3 specimen are consistent with effects arising from spin–orbit interaction at the surface of the Bi2Se3 topological insulator.
Autors: Alviu Rey Nasir;Taehee Yoo;Seul-Ki Bac;Hakjoon Lee;Sangyeop Lee;Seonghoon Choi;Sanghoon Lee;Xinyu Liu;M. Dobrowolska;Jacek K. Furdyna;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effects of 3-D Printed Structural Characteristics on Magnetic Properties
Abstract:
Additive manufacturing, particularly 3-D printing, allows for completely customizable designs with relatively no limits on geometric complexities. In order to ensure optimal part design for potential magnetic applications, it is crucial to study how the different 3-D printer settings impact the magnetic properties of the printed part. Specifically, in this paper, it was determined how three structural print parameters (outer shell thickness, internal fill factor, and internal layer orientation) affect the resulting magnetic properties of 3-D printed cubic samples. The samples are made using fused deposition modeling of an iron–polymer composite filament. Hysteresis loops were gathered for fields applied along the [100], [110], and [001] directions of the printed cubes. From this, it was determined which combination of print settings should be used to achieve the most desirable magnetic response in terms of magnetic susceptibility, net magnetic moment, and mass-normalized saturation magnetization.
Autors: Lindsey M. Bollig;Michael V. Patton;Greg S. Mowry;Brittany B. Nelson-Cheeseman;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Effects of Cu Addition on Magnetic Properties and Microstructures of Annealed Zr–Co–Cu–B Ribbons
Abstract:
The magnetic properties and microstructures of Zr18Co82−xCuxB2 (, 1, 2, 3, and 4) ribbons fabricated by melt-spinning technique were investigated to analyze the effects of Cu addition on the stabilization of a hard magnetic rhombohedral Zr2Co11 phase. In as-spun ribbons, the proportion of the rhombohedral Zr2Co11 phase increased up to . In addition, it was found that the Cu addition inhibited the decomposition of the rhombohedral Zr2Co11 phase into Co and ZrCo5 phases during the post-annealing process. In particular, annealed Zr18Co79Cu3B2 ribbons showed that the recrystallized grains having rhombohedral Zr2Co11 phase were grown as aligned rod-shaped grains with lengths of 200 nm. Thus, the Cu addition increased the coercivity of both as-spun and annealed ribbons. A maximum coercivity of 4.7 kOe was obtained in Zr18Co80Cu2B2 ribbons annealed at 550 °C.
Autors: Gyutae Lee;Jongryoul Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effects of DC Bias Current on Behavior and Sensitivity of Thin-Film Magnetoimpedance Element
Abstract:
We investigated the behaviors and sensitivity of thin-film magnetoimpedance elements having an easy axis angle of 0°–45° when applying dc bias current directly to the elements. All elements show symmetric impedance profiles with respect to the impedance axis without dc bias current, while their profiles become asymmetric with dc bias current. This appearance of the asymmetric property on the impedance profiles indicates that the shape of cross section of the element has asymmetric configuration. On the other hand, when the easy axis angle is relatively small, the sensitivity for field detection is enhanced with a small dc bias level, while a stronger bias level is required for the element with a larger easy axis angle. The obtained results show a potential to optimize the sensor properties by dc bias current with small intensity in case that design properties are not obtained in the fabrication process.
Autors: H. Kikuchi;C. Sumida;T. Nakai;S. Hashi;K. Ishiyama;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effects of Electrical and Optogenetic Deep Brain Stimulation on Synchronized Oscillatory Activity in Parkinsonian Basal Ganglia
Abstract:
Conventional deep brain stimulation of basal ganglia uses high-frequency regular electrical pulses to treat Parkinsonian motor symptoms but has a series of limitations. Relatively new and not yet clinically tested, optogenetic stimulation is an effective experimental stimulation technique to affect pathological network dynamics. We compared the effects of electrical and optogenetic stimulation of the basal gangliaon the pathologicalParkinsonian rhythmic neural activity. We studied the network response to electrical stimulation and excitatory and inhibitory optogenetic stimulations. Different stimulations exhibit different interactions with pathological activity in the network. We studied these interactions for different network and stimulation parameter values. Optogenetic stimulation was found to be more efficient than electrical stimulation in suppressing pathological rhythmicity. Our findings indicate that optogenetic control of neural synchrony may be more efficacious than electrical control because of the different ways of how stimulations interact with network dynamics.
Autors: Shivakeshavan Ratnadurai-Giridharan;Chung C. Cheung;Leonid L. Rubchinsky;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2188 - 2195
Publisher: IEEE
 
» Effects of Glycine in DES-Based Plating Baths on Structural and Magnetic Properties of Fe–Ni Films
Abstract:
We have already reported that a deep eutectic solvent is one of hopeful solvents to obtain an electroplated Fe-based soft magnetic film since the plating process shows high current efficiency. In this paper, we employed glycine as an additive to improve surface roughness and soft magnetic properties of electroplated Fe–Ni films. The coercivity of the Fe-rich films (>70 at.%) prepared from the glycine-used bath showed lower values compared with those for the no-glycine baths. From the evaluations for the surface roughness and the crystal structure of the as-plated Fe75Ni25 films, we considered that the reductions in the coercivity of the Fe-rich films for the glycine-used baths are attributed to the smooth surface and the reduction in the effective crystalline anisotropy by increase in the volume fraction of an amorphous magnetic phase in the film.
Autors: T. Yanai;T. Yamaguchi;T. Akiyoshi;K. Takashima;M. Nakano;H. Fukunaga;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effects of Liner Thickness on the Reliability of AgTe/TiO2-Based Threshold Switching Devices
Abstract:
The effects of liner thickness on the reliability of AgTe/TiO2-based threshold switching (TS) devices were investigated. The off-state current of an AgTe/TiO2/Pt TS device was found to be significantly increased by in-diffusion of Ag into the TiO2 layer during the annealing process. Therefore, 3-, 5- and 7-nm TiN liners were introduced and compared to prevent the in-diffusion of Ag. While the 3-nm TiN liner was shown to be incapable of blocking Ag in-diffusion into the TiO2 layer, the 5- and 7-nm liners effectively suppressed in-diffusion and maintained high off-state resistance. However, the TS device with the 7-nm TiN liner exhibited wide threshold voltage distribution and poor endurance characteristics owing to a lack of Ag sources. The TS device with a 5-nm TiN liner, by contrast, was found to have an adequate amount of Ag sources and to demonstrate thermally stable and electrically reliable characteristics. The effects of TiN liner on Ag diffusion were also directly confirmed using energy dispersive spectrometry line profiles, transmission electron microscopy imaging, and mapping analyses.
Autors: Jeonghwan Song;Jiyong Woo;Jongmyung Yoo;Solomon Amsalu Chekol;Seokjae Lim;Changhyuck Sung;Hyunsang Hwang;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4763 - 4767
Publisher: IEEE
 
» Effects of Pt Buffer Layer and Sr Content on Multiferroic (Bi, Sr)FeO3 Polycrystalline Thin Films on Glass Substrates
Abstract:
Effects of Pt buffer layer and Sr content on the structure, surface morphology, ferroelectric, and magnetic properties of Bi1-xSrxFeO3 (BSFO) polycrystalline films on glass substrates at reduced temperature of 450 °C have been investigated. Perovskite single phase is present in the studied BSFO films (–0.15) on 10–30 nm thick Pt(111) electrodes. The grain size and surface roughness of BSFO films is closely related to the morphology of Pt(111) electrodes. Further refined microstructure with reduced surface roughness is found with the increase of Sr content . BSFO polycrystalline thin films display good ferroelectric properties with the remanent polarization (2Pr) of 77–103 /cm2 and electrical coercive field ( of 380–490 kV/cm. In addition, the enhanced ferromagnetic properties with magnetization () of 8.7–11.2 emu/cm3 and coercivity () of 1211–1299 Oe are attained.
Autors: H. W. Chang;C. Y. Shen;F. T. Yuan;Y. C. Lo;S. Y. Lin;C. F. Chang;C. R. Wang;C. S. Tu;S. U. Jen;W. C. Chang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Effects of Silicon Content on the Properties of Gas-Atomized Fe–Si–Cr Powders
Abstract:
Fe-7%, 8%, 9%, and 11%Si–Cr powders were gas atomized and then annealed at 25 °C–750 °C to investigate the effects of Si content, DO3 phase, and B2 phase on the high-frequency permeability of the powders. The formation of the B2 phase could not be suppressed during the atomization process of all the powders. The evolution temperatures of the DO3 phase in the Fe-7%, 8%, and 9%Si–Cr powders as measured by X-ray diffractometer were 550 °C, 550 °C, and 450 °C, respectively. As the annealing temperature was increased, the DO3 phase grew rapidly, and the lattice parameters of the powders were decreased except for those of the Fe-11%Si–Cr powder. The coercivity of all powders decreased with increasing temperature; however, the coercivity of the Fe-8%, 9%Si–Cr powders increased sharply after annealing at 450 °C. Permeability decreased rapidly with increasing temperature except for the Fe-11%Si–Cr powder; thus, the highest real permeability was obtained for the as-atomized Fe-8%Si–Cr powder. The changes in the coercivity and permeability of the powders with annealing temperature could be attributed to the evolution of the DO3 phase, Si segregation, and changes in electrical resistivity.
Autors: Pyungwoo Jang;Gwangbo Choi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Efficiency, Stability, and Reliability Implications of Unbalanced Current Sharing Among Distributed On-Chip Voltage Regulators
Abstract:
Power delivery networks with distributed on-chip voltage regulators (VRs) serve as an effective way for fast localized voltage regulation within modern microprocessors. Without careful consideration of the interactions among the distributed VRs and the power grid, unbalanced current sharing (CS) among those regulators may, however, lead to efficiency degradations, stability, and reliability issues, and even malfunctions of the regulators. This paper is a first attempt to investigate the efficiency, stability, and reliability implications of unbalanced CS among distributed on-chip VRs. Benefits of balanced CS are demonstrated with concrete examples, showing the necessity of an appropriate current balancing scheme. An adaptive reference voltage control method and the corresponding control algorithms specifically for distributed on-chip VRs are proposed to balance the CS among regulators at different locations. The proposed techniques successfully balance the CS among distributed VRs and can be applied to different regulator types. Simulation results based on practical microprocessor setups confirm the efficiency, stability, and reliability implications.
Autors: Longfei Wang;S. Karen Khatamifard;Orhun Aras Uzun;Ulya R. Karpuzcu;Selçuk Köse;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 3019 - 3032
Publisher: IEEE
 
» Efficient Data Center Flow Scheduling Without Starvation Using Expansion Ratio
Abstract:
Existing data center transport protocols are usually based on the Processor Sharing (PS) policy and/or the Shortest Remaining Processing Time (SRPT) policy. PS divides link bandwidth equally between competing flows, thus it fails to achieve optimal average flow completion time (FCT). SRPT prioritizes flows that have the shortest remaining processing time and provides near-optimal average FCT, but it may cause long flows to suffer unfair delays, or even starve them. In fact, these two types of policies represent two directions in the design space: PS prefers fairness (in terms of starvation freedom) while SRPT favors efficiency (in terms of average FCT). In this paper, we propose a novel metric, expansion ratio, which enables us to strike a balance between SRPT and PS. We design MERP that achieves efficient flow scheduling without starvation. MERP takes care of both average and tail FCTs by minimizing the expansion ratio of competing flows in a lexicographically manner. MERP controls the sending rate of competing flows via synchronized virtual deadlines and routes flows in a downstream-aware manner that reacts quickly to link failures. We evaluate MERP using extensive NS2-based simulations. Results show that, under various traffic loads, MERP reduces the tail FCT significantly with a negligible increase of average FCT compared with pFabric, and MERP reduces the average FCT notably compared with ECMP and CONGA when link failures occur.
Autors: Sheng Zhang;Zhuzhong Qian;Hao Wu;Sanglu Lu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3157 - 3170
Publisher: IEEE
 
» Efficient Evaluation of Multichannel SAR Data Recombination Filters
Abstract:
Synthetic aperture radar (SAR) is a well-established technique for observing the Earth on a global scale. As applications become more demanding, it is desirable to overcome the limitations imposed by the SAR principle, one of which is the tradeoff between the swath width and the instantaneous azimuth bandwidth, determining the resolution. Recombination of multiple channels with displaced phase centers has been proposed as a convenient way to create high resolution wide-swath images. We analyze various approximations made in the channel transfer functions and their impact on the reconstruction result using examples inspired by current imaging modes of the TerraSAR-X and TanDEM-X missions. In order to do so, we introduce an efficient method to assess the quality of reconstruction filters for an arbitrary number of channels without the need of full time-domain simulations.
Autors: Moritz Kiemer;Helko Breit;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6277 - 6286
Publisher: IEEE
 
» Efficient Method for Scattering From Cylindrical Components of Vegetation and Its Potential Application to the Determination of Effective Permittivity
Abstract:
Reliable and efficient analysis of electromagnetic scattering by cylindrical components of vegetation is important for microwave remote sensing of vegetated terrain. It allows for the characterization of anistropicity of the effective permittivity for vegetation or tree canopy, where averaging operation over distribution of cylinder orientation is needed in general. In this paper, we propose a T-matrix formulation based on our virtual partition method (VPM) for the whole cylindric component of either homogeneous or inhomogeneous nature. Numerical simulations demonstrate that the proposed T-matrix preserves all the desirable features of the VPM method, including high fidelity prediction of the scattering amplitude function and fulfillment of energy conservation as well as the reciprocity theorem. More importantly, in the evaluation of averaging over orientation distribution, the proposed method is usually faster than the VPM by two orders of magnitude. The predicted effective permittivity for an exemplary orientation distribution shows appreciable difference from that of the infinite cylinder approximation. With its qualitatively characterized region of validity, the proposed method is expected to be helpful in multiband coherent scattering models of vegetated terrain.
Autors: Dejun Li;Chao Yang;Yang Du;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Nov 2017, volume: 55, issue:11, pages: 6120 - 6127
Publisher: IEEE
 
» Efficient Resource Allocation in Device-to-Device Communication Using Cognitive Radio Technology
Abstract:
Device-to-device (D2D) communication is developed as a new paradigm to enhance network performance according to LTE and WiMAX advanced standards. The D2D communication may have dedicated spectrum (overlay) or shared spectrum (underlay). However, the allocated dedicated spectrum may not be effectively used in the overlay mode, while interference between the D2D users and cellular users cause impairments in the underlay mode. Can the resource allocation of a D2D system be optimized using the cognitive approach where the D2D users opportunistically access the underutilized radio spectrum? That is the focus of this paper. In this paper, the transmission rate of the D2D users is optimized while simultaneously satisfying five sets of constraints related to power, interference, and data rate, modeling D2D users as cognitive secondary users. Furthermore, a two-stage approach is considered to allocate the radio resources efficiently. A new adaptive subcarrier allocation scheme is designed first, and then, a novel power allocation scheme is developed utilizing geometric water-filling approach that provides optimal solution with low computation complexity for this nonlinear problem. Numerical results show that the proposed approach achieved significant performance enhancement than the existing schemes.
Autors: Ajmery Sultana;Lian Zhao;Xavier Fernando;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10024 - 10034
Publisher: IEEE
 
» Electric Field Tuning Ferromagnetic Resonance Frequency Shift in Oblique Sputtered Fe42Co46Hf12/PZN-PT Multiferroic Heterostructures
Abstract:
Strong inverse magnetoelectric (ME) coupling was observed in Fe42Co46Hf12/Lead Zinc Niobate–Lead Titanate multiferroic heterostructure, which produced a large electric field (E-field) tunability on microwave magnetic properties. With the increase of the E-field from 0 to 8 kV/cm, the E-field-dependent linearly increases from 175 to 411 Oe, equivalent to a large ME tunability of /kV, which further leads to a significant enhancement of ferromagnetic resonance frequency from 4.13 to 6.28 GHz under zero bias magnetic field. These features demonstrate that this multiferroic composite is a promising candidate for fabricating E-field-tunable microwave components.
Autors: Shandong Li;Xiaomin Liu;Honglei Du;Qiang Li;Jie Xu;Xia Wang;Hwaider Lin;Nian X. Sun;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Electrical and Methanol Sensing Characteristics of RF Sputtered n-ZnO/p-Si Heterojunction Diodes
Abstract:
This paper reports structural, electrical, and gas sensing characteristics of n-ZnO/p-Si heterojunction diodes fabricated using RF sputtering technique. The microstructural and surface morphological properties have been studied using X-ray diffraction, atomic force microscopy, and scanning electron microscopy, respectively. The electrical properties of the fabricated diodes have been investigated using current-voltage (–) and capacitance-voltage (–) measurements. The estimated values for rectification ratio, ideality factor, and barrier height were found to be ~100, 3.27, and 0.72eV, respectively, at room temperature. The values recorded for carrier concentration and barrier height using – measurement were cm and 0.79 eV, respectively. The value of series resistance using Chueng’s function was found to be 1710 . After detailed structural and electrical characterization, methanol sensing response (3–100 ppm) of n-ZnO/p-Si heterojunction diodes for the temperature range of 27 °C–150 °C have also been investigated. The optimum operating temperature for methanol sensing was found to be considerably low,- i.e., 100 °C. The values of response magnitude, response time and recovery time at 100 °C were estimated as 82%, ~4 and ~7 s, respectively. The cross sensitivity study for the nearest interfering species, such as ethanol, 1-propanol, butanol, butanone, and benzene, has confirmed the high selectivity of n-ZnO/p-Si heterojunction diodes for methanol sensing.
Autors: Shashi Kant Sharma;Basanta Bhowmik;Vipin Pal;Chinnamuthan Periasamy;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7332 - 7339
Publisher: IEEE
 
» Electrical Balance Duplexer Field Trials in High-Speed Rail Scenarios
Abstract:
Electrical balance duplexers (EBDs) present a potential alternative to the fixed-frequency duplexing filters used for frequency division duplexing in cellular handset radio frequency front ends. However, the transmit-to-receive (Tx–Rx) isolation can be affected by interaction between the antenna and the environment, and therefore, the EBDs balancing impedance must adaptively track time-domain antenna impedance variation. A rail scenario presents a potentially demanding use case for an EBD, as fast moving trains in the vicinity of the antenna may cause dynamically changing reflections, which can be received as self-interference. In this paper, measured dynamic antenna reflection coefficients at 745 and 1900 MHz from train mounted antennas are included in the EBD circuit simulations in order to investigate the resulting variation in Tx–Rx isolation, and determine requirements for balancing impedance adaptation. This paper also presents the results from rail-based field trials of a hardware prototype EBD, which implements real-time antenna impedance tracking. Results show that the rail scenario does result in variation in Tx–Rx isolation, but that rebalancing the EBD at the intervals of 5 ms was sufficient to maintain >50 dB isolation for ~95% of the time.
Autors: Leo Laughlin;Chunqing Zhang;Mark A. Beach;Kevin A. Morris;John L. Haine;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6068 - 6075
Publisher: IEEE
 
» Electrical Impedance Myography for Evaluating Paretic Muscle Changes After Stroke
Abstract:
Electrical impedance myography (EIM) was used to assess the paretic muscle intrinsic electrical properties post stroke. Twenty-seven subjects with chronic hemiparesis participated in this study. Muscle impedance was measured by applying high-frequency, low-intensity alternating current to biceps brachii muscles. Major EIM parameters, resistance (), reactance (), phase angle (), and electrical anisotropy ratios (AR) of the three parameters, were examined at 50 kHz. Statistical analysis demonstrated significant reduction of reactance, phase angle, AR of resistance, and AR of reactance in the paretic muscle compared with the contralateral side (Paretic X: , contralateral X: , and p < 0.001; Paretic : , contralateral : 14.5 ± 0.82°, and p < 0.001; Paretic AR of R: 0.969 ± 0.013, contralateral AR of R: 1.008 ± 0.011, and p < 0.02; and Paretic AR of X: 0.981 ± 0.066, contralateral AR of X: 1.114 ± 0.041, and p < 0.02). Correlation analysis, however, did not show any significant relationship between EIM parameters and clinical assessments. Findings of this paper indicate- significant changes in the muscular intrinsic electrical properties after stroke, possibly related to structural modifications induced by loss of muscle fibers or fat infiltration as well as changes in the quality of cell membranes post stroke.
Autors: Xiaoyan Li;Le Li;Henry Shin;Sheng Li;Ping Zhou;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2113 - 2121
Publisher: IEEE
 
» Electrical Impedance Tomography: Tissue Properties to Image Measures
Abstract:
Electrical impedance tomography (EIT) uses electrical stimulation and measurement at the body surface to image the electrical properties of internal tissues. It has the advantage of noninvasiveness and high temporal resolution but suffers from poor spatial resolution and sensitivity to electrode movement and contact quality. EIT can be useful to applications, where there are conductive contrasts between tissues, fluids, or gasses, such as imaging of cancerous or ischemic tissue or functional monitoring of breathing, blood flow, gastric motility, and neural activity. The past decade has seen clinical application and commercial activity using EIT for ventilation monitoring. Interpretation of EIT-based measures is complex, and this review paper focuses on describing the image interpretation “pathway.” We review this pathway, from Tissue Electrical Properties, EIT Electrodes & Hardware, Sensitivity, Image Reconstruction, Image Processing to EIT Measures. The relationship is discussed between the clinically relevant parameters and the reconstructed properties. An overview is given of areas of EIT application and of our perspectives for research and development.
Autors: Andy Adler;Alistair Boyle;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2494 - 2504
Publisher: IEEE
 
» Electrical Properties Tomography Based on $B_{{1}}$ Maps in MRI: Principles, Applications, and Challenges
Abstract:
Objective: The purpose is to provide a comprehensive review of the electrical properties tomography (EPT) technique, which was introduced to image the electrical properties (EPs) of tissue noninvasively by exploiting the measured field data of MRI. Methods: We reviewed the principle of EPT, reconstruction methods, biomedical applications such as tumor imaging, and existing challenges. As a key application of EPT, the estimation of specific absorption rate (SAR) due to MRI was discussed in the background of elevated risk of tissue heating at high field. Results and Conclusion: Since the originally proposed local, homogeneous Helmholtz equation-based reconstruction algorithm, advanced EPT algorithms have emerged to address the challenges of EPT, including reconstruction error near tissue boundaries, noise sensitivity, inaccurate phase estimation, and elimination of the unmeasurable component, along with demonstrations of in vivo experiments. EPT techniques have been applied to investigate EPs of both healthy and pathological tissues in vivo and factors contributing to various EP value, including sodium, water content, etc. More studies are anticipated to consolidate the current findings. EPT-based subject-specific SAR estimation has led to in vivo demonstration of its feasibility and prediction of temperature increase of phantom during MRI scans merely using measured data. Significance: EPT has the advantage of high resolution and practical feasibility in a clinical setup for imaging the biomedically interesting EPs of tiss- e in the radiofrequency range. EPT-based SAR estimation is another promising topic for predicting tissue heating of individual subjects during a specific MRI scan.
Autors: Jiaen Liu;Yicun Wang;Ulrich Katscher;Bin He;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Nov 2017, volume: 64, issue:11, pages: 2515 - 2530
Publisher: IEEE
 
» Electrical–Thermal Characterization of Through Packaging Vias in Glass Interposer
Abstract:
Low-cost thin glass is developed as a promising material to advanced interposers for high density electrical interconnection in 2.5-D and three-dimensional (3-D) integration. In this paper, the electrical–thermal performance of through glass vias is investigated. The distributed transmission lines model for tapered through glass vias (T-TGVs) in signal-ground-signal type differential structure is first established and validated against the 3-D full-wave electromagnetic simulator. The model is applicable to TGVs made of carbon nanotubes(CNTs) by incorporating CNT quantum and kinetic effects. Using the proposed model, the impact of various parameters on the electrical characteristics of the differential T-TGVs is investigated. It is observed that the inductive element of conductor loss plays a significant role on the electrical performance, which makes the CNT-TGV interconnects show unique electrical characterization that totally different from its through silicon vias (TSVs) counterpart. For example, the signal loss of TGV interconnects in different-mode signaling is even lower than that in common-mode and increasing via pitch increases signal loss. Furthermore, the thermal performance of 2.5-D integration with TGVs is investigated with COMSOL multiphysics. It is shown that TGV is a primary path for heat dissipation and increasing TGV distribution density can significantly lower the peak temperature of 2.5-D integration. Because of high thermal conductivity of CNTs, glass interposer with CNT-TGVs can achieve better thermal performance in comparison to its Cu counterpart.
Autors: Libo Qian;Yinshui Xia;Ge Shi;Jiang Wang;Yidie Ye;Shimin Du;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 901 - 908
Publisher: IEEE
 
» Electrically “Long” Dipoles in a Collocated/Orthogonal Triad—for Direction Finding and Polarization Estimation
Abstract:
In dipole-antenna array signal-processing algorithm development, research has focused on “short dipoles” whose physical length () is under (1/10) of a wavelength . Such electrically “short” dipoles have very small input impedances, rendering such “short” dipoles to be inefficient radiators. Practical dipoles, with an electrical length of , have notably larger input impedance, hence making them better radiators. Of such practical dipoles, this paper investigates their use for azimuth-polar direction finding and for polarization estimation. This paper will first present the measurement model (i.e., array manifold) of a triad of such practical dipoles, collocated in space and orthogonally oriented. This paper will then develop the corresponding closed-form algorithms to estimate the bivariate azimuth–elevation direction-of-arrival or the bivariate polarization. Such closed-form algorithms previously have been unavailable in the existing literature for such a triad of electrically “long” dipoles of pragmatic radiation efficiency.
Autors: Kainam Thomas Wong;Yang Song;Caleb J. Fulton;Salman Khan;Wai-Yip Tam;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 6057 - 6067
Publisher: IEEE
 

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