Electrical and Electronics Engineering publications abstract of: 11-2017 sorted by title, page: 8

» Energy Efficient Beamforming for Massive MIMO Public Channel
Abstract:
For massive MIMO public channel with any sector size in either microwave or millimeter wave (mmwave) band, this paper studies the beamforming design to minimize the transmit power while guaranteeing the quality of service for randomly deployed users. First the ideal beampattern is derived via Parseval Identity, based on which a beamforming design problem is formulated to minimize the gap with the idea beampattern. The problem is transformable to a multiconvex one and an iterative optimization algorithm is used to obtain the full-digital beamformer. In addition, with the help of same beampattern theorem, the power amplifier efficiency of the beamformer is improved with unchanged beampattern. Finally, the practical hybrid implementation is obtained that achieves the full-digital beamformer solution. Simulations verify the advantages of the proposed scheme over existing ones.
Autors: Cheng Zhang;Yongming Huang;Yindi Jing;Luxi Yang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10595 - 10600
Publisher: IEEE
 
» Energy Investment Planning at a Private Company: A Mathematical Programming-Based Model and Its Application in Turkey
Abstract:
We consider a mid-sized private electricity generating company that plans to enter the market that is partially regulated. There is a cap and trade system in operation in the industry. There are nine possible power plant types that the company considers to invest on through a planning horizon. Some of these plants may include a carbon capture and storage technology. We develop a stochastic mixed-integer linear program for this problem where the objective is to maximize the expected net present value of the profit obtained. We include restrictions on the maximum and minimum possible amount of investment for every type of investment option. We also enforce market share conditions such that the percentage of the total investments of the company over the total installed capacity of the country stay between upper and lower bounds. Moreover, in order to distribute the investment risk, the percentage of each type of power plant investment is restricted by some upper bound. We tested the model for a hypothetical company operating in Turkey. The results show that the model is suitable to be used for determining the investment strategy of the company.
Autors: Semra Ağralı;Fulya Terzi;Ethem Çanakoğlu;Esra Adıyeke;Yıldız Arıkan;
Appeared in: IEEE Transactions on Power Systems
Publication date: Nov 2017, volume: 32, issue:6, pages: 4180 - 4187
Publisher: IEEE
 
» Energy Management in Hybrid Energy Large-Scale MIMO Systems
Abstract:
This paper investigates the energy consumption of distributed large-scale MIMO systems made up of a set of remote radio heads (RRHs), each of which is powered by both an independent energy harvesting source and the grid. The grid energy source allows to compensate for the randomness and intermittency of the harvested energy. Hence, the problem of grid power consumption minimization has to be solved by efficiently managing the energy delivered from different sources while satisfying the system requirements in terms of users’ quality of service demands. First, this paper solves the optimal offline version of the problem using linear programming. In fact, the main problem is decomposed and heuristically solved in order to deal with the large number of constraints and variables. Since sometimes all the users cannot be served, an iterative link removal algorithm is devised ensuring the feasibility of the problem. Next, we investigate the online energy management problem. We first propose a dynamic programming approach to obtain the optimal online solution but with high complexity. Then, we develop and propose a low complexity heuristic solution based on using the maximal available energy at the batteries. Taking benefits of the characteristics of large-scale MIMO and the modeling of the harvested energy as Markov chains, we devise an efficient online energy management algorithm based on energy prediction. Finally, we propose a heuristic solution for RRH on/off operation with the objective of improving the system energy efficiency. The performance of the proposed algorithms is evaluated by simulations and it is shown that the proposed energy management approaches offer efficient use of nonrenewable energy to compensate the variability of renewable energy in large-scale MIMO systems.
Autors: Rami Hamdi;Elmahdi Driouch;Wessam Ajib;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10183 - 10193
Publisher: IEEE
 
» Energy Savings in Integrated Urban Water Systems: A Case Study
Abstract:
Energy efficiency policies require the implementation of strategies to reduce energy use during the operation of integrated urban water systems. In Italy, the overall amount of electrical energy consumption for water systems is close to 2.3% of the total national consumption, thus efforts to minimize costs are crucial. This paper analyzes a case study of urban water systems in a specific area in the Piedmont Region, Italy; the case study includes the data collection methodology and the analysis of the energy consumption of seven large water providers. The discussion includes the quantification of the energy consumption reduction, achievable with the replacement of existing transformers with high-efficiency transformers, power factor correction, and the use of variable-frequency drives for the centrifugal pumps.
Autors: Stefano Paolo Corgnati;Massimo Mitolo;Lara Orlietti;Michele Tartaglia;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5150 - 5154
Publisher: IEEE
 
» Energy Storage and Power Electronics Technologies: A Strong Combination to Empower the Transformation to the Smart Grid
Abstract:
The electric power industry is facing unprecedented transformations and challenges with the implementation of the smart grids. This new grid paradigm has arisen to build a flexible electric power system that better coordinates energy resources and loads aiming at efficiently delivering sustainable, economic and secure electricity supplies. As a part of the smart grids (SGs), microgrids (MGs) have been developed to exploit the full benefits from the integration of distributed energy resources, especially distributed renewable generation based on variable and intermittent sources, such as wind and solar. Nevertheless, meeting all these goal requires the implementation of innovative energy storage technologies integrated with high efficiency and very fast response electronic power conditioning systems to interface with the electrical grid. Power electronics systems play a key role in regulating the raw energy from energy storage systems (ESSs) and connecting to the electrical grid. Hence, this paper performs a comprehensive analysis of major technologies in electrical energy storage systems and their electronic interface for applications in smart grids. The work provides a complete study of the technology profile of both energy storage and power electronics suitable for applications in the evolving grid.
Autors: Marcelo G. Molina;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 2191 - 2219
Publisher: IEEE
 
» Energy-Efficient Computing With Probabilistic Magnetic Bits—Performance Modeling and Comparison Against Probabilistic CMOS Logic
Abstract:
This paper focuses on the design, performance modeling, and evaluation of probabilistic logic using superparamagnetic nanomagnets for which there exists a strong interplay between deterministic dynamics and intrinsic thermal noise. The switching element in the spin domain is chosen as the giant spin-Hall effect (GSHE) device that operates based on the dipolar coupling phenomenon in a two-magnet system to achieve low-energy ( fJ/b) and low-power ( W) switching characteristics. The use of spin currents on the order of a few tens of mA/m2 in the subcritical regime to operate the GSHE device yields nondeterministic switching behavior with probability of correctness less than 100%. Therefore, the proposed technique allows us to trade off circuit accuracy for tremendous reduction in energy and power dissipation. In this paper, we identify the required dimensions and material parameters of the read–write units to ensure robust magnetic dipolar coupling for reliable operation of the GSHE switch. Then, through Monte Carlo simulations, we evaluate the probabilistic switching behavior of the GSHE switch as a function of the input spin current amplitude and pulsewidth for various orientations of the magnetization vectors. The delay of the GSHE switch is quantified using a probability distribution function owing to the randomness imparted to the dynamics by intrinsic thermal noise of the nanomagnets. The relationship between the probability of correctness and the energy dissipation of the GSHE switch is quantified. The results are extended to evaluate the performance and circuit error rate of complex logic gates, such as NAND and NOR, constructed using the GSHE switch. It is s- own that unlike the probabilistic CMOS (PCMOS) logic, the circuit error rate in the GSHE logic becomes a function of the input vector combination and the prior state of the switch. These nuances are captured in the compact model of the circuit error rate of multiple-input GSHE logic developed in this paper. The performance of the probabilistic GSHE logic is compared with that of PCMOS logic at the 14 nm technology node. Since the noise generation process in PCMOS logic has a limited bandwidth of tens of megahertz and consumes tens of microwatt power, the peripheral circuitry becomes prohibitive. By utilizing the inherent thermal stochasticity, nanomagnets provide a clear advantage to implement probabilistic computing platform targeted toward error-tolerant applications such as those from the image processing and machine learning domains.
Autors: Nikhil Rangarajan;Arun Parthasarathy;Nickvash Kani;Shaloo Rakheja;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 10
Publisher: IEEE
 
» Energy-Efficient Design of Processing Element for Convolutional Neural Network
Abstract:
Convolutional neural network (CNN) is the most prominent algorithm for its wide usage and good performance. Despite the fact that the processing element (PE) plays an important role in CNN processing, there has been no study focusing on PE design optimized for state-of-the-art CNN algorithms. In this brief, we propose an optimal PE implementation including a data representation scheme, circuit block configurations, and control signals for energy-efficient CNN. To validate the excellence of this brief, we compared our proposed design with several previous methods, and fabricated a silicon chip. The software simulation results demonstrated that we can reduce 54% of data bit lengths with negligible accuracy loss. Our optimization on PE achieves to save computing power up to 47%, and an accelerator exploiting our method shows superior results in terms of power, area, and external DRAM access.
Autors: Yeongjae Choi;Dongmyung Bae;Jaehyeong Sim;Seungkyu Choi;Minhye Kim;Lee-Sup Kim;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Nov 2017, volume: 64, issue:11, pages: 1332 - 1336
Publisher: IEEE
 
» Energy-Efficient Localization Game for Wireless Sensor Networks
Abstract:
We study the energy saving problem of nodes for the hybrid directions of arrival/received signal strength (DoA/RSS) localization scheme in wireless sensor networks. To solve this problem, both the transmission power and the sleep times of the anchor nodes are allocated while the target is required to be localized with a pre-specified accuracy. We use the leader–follower Stackelberg game to model our problem, in which, the target is the follower and the set of the target’s neighbor anchor nodes, named coalition of anchor nodes (CANs), is the leader. We prove the existence and uniqueness of the Stackelberg equilibrium (SE) by giving closed-form expressions for the SE strategies of both the target and the CANs. The superior performance of the proposed scheme is validated through simulations.
Autors: ThiOanh Bui;Pingping Xu;Wenxiang Zhu;Guilu Wu;Nanlan Jiang;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2468 - 2471
Publisher: IEEE
 
» Energy-Efficient Train Control by Multi-Train Dynamic Cooperation
Abstract:
Regenerative braking technology has been widely used by subway trains, where regenerative braking energy (RBE) will be generated during train braking processes. An RBE usage method is proposed for subway trains, where train braking processes are predicted based on the field data of the train control system, and the braking information will be obtained in advance. The RBE will be calculated, and then, part or all of it will be distributed to neighboring trains in the same or adjacent power supply sections. Several feasible schemes for the RBE distribution are given, where the speed profiles of the neighboring trains will be adjusted to absorb the distributed RBE. An optimal RBE distribution scheme with the most effective usage of RBE will be obtained based on calculation results of the given schemes. For each adjusted speed profile of the neighboring train, a power process will be normally introduced. Existence of the optimal solution for speed profile adjustment is analyzed under the precondition that the train runs in a long speed-holding journey, and then, the necessary condition of the optimal solution is found by perturbance analysis. A simulation case of Yizhuang Line in Beijing subway is studied, and the simulation results show that the proposed method can use the RBE efficiently.
Autors: Xubin Sun;Hong Lu;Hairong Dong;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 3114 - 3121
Publisher: IEEE
 
» Energy-Saving Project of 5500-HP 13-kV Wound Rotor Induction Motor on a Kiln ID Fan Using a Low-Voltage Slip Power Recovery Drive—A Case Study
Abstract:
Once upon a time, there was a cement kiln with a 5500-HP induced draft (ID) fan powered by a wound rotor induction motor. The process controlled the airflow with an inlet damper operating in 35% open range. The plant wished for a more energy efficient means of controlling airflow and power demand for this fan. This paper reviews the options and decision processes that made this wish come true. A novel method was used to reduce the power consumed and control the fan's speed based on a lower airflow demand. The solution was implemented with participation from the utility, the energy saving consultants, and the equipment suppliers. This paper also covers the challenges presented by the ID Fan wound rotor motor design, the plant operational situation, and the technology selected to solve the problem. Details of the wound rotor motor speed control will be discussed and its application reviewed. The significant energy savings and process improvements are covered as well.
Autors: Doug Phares;Tim Ruegg;Kelly Fishel;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5997 - 6001
Publisher: IEEE
 
» Energy-Sustainable Traffic Steering for 5G Mobile Networks
Abstract:
Renewable EH technology is expected to be pervasively utilized in 5G mobile networks to support sustainable network developments and operations. However, the renewable energy supply is inherently random and intermittent, which could lead to energy outage, energy overflow, QoS degradation, and so on. Accordingly, how to enhance renewable energy sustainability is a critical issue for green networking. To this end, an energy-sustainable traffic steering framework is proposed in this article, where the traffic load is dynamically adjusted to match energy distributions in both the spatial and temporal domains by means of interand intra-tier steering, caching, and pushing. Case studies are carried out, which demonstrate that the proposed framework can reduce on-grid energy demand while satisfying QoS requirements. Research topics and challenges of energy-sustainable traffic steering are also discussed.
Autors: Shan Zhang;Ning Zhang;Sheng Zhou;Jie Gong;Zhisheng Niu;Xuemin (Sherman) Shen;
Appeared in: IEEE Communications Magazine
Publication date: Nov 2017, volume: 55, issue:11, pages: 54 - 60
Publisher: IEEE
 
» Enhanced and Fast Detection of Open-Switch Faults in Inverters for Electric Drives
Abstract:
Open-switch faults in inverter-driven electric drives have recently gained increasing attention in the scientific community. Since these faults may lead to undesired effects, their fast and unambiguous detection is desirable. This paper proposes a detection algorithm for open-switch faults, which is based on the observation of the current control deviation and a subsequent test procedure. This algorithm detects the fault immediately after its occurrence within a few switching periods, even during transient operation. The proposed method is tested via simulations and experiments at different operating points of a surface permanent magnet drive.
Autors: Heinrich T. Eickhoff;Roland Seebacher;Annette Muetze;Elias G. Strangas;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5415 - 5425
Publisher: IEEE
 
» Enhanced Anisotropy in Tetragonalized (Cu,Co)Fe2O4 Particles via the Jahn–Teller Effect of Cu2+ Ions
Abstract:
We studied the Jahn–Teller (JT) effect of Cu2+ ions on the tetragonalization of CuFe2O4 and (Cu,Co)Fe2O4 particles. Sub-micrometer-sized CuFe2O4 and (Cu,Co)Fe2O4 particles were synthesized via coprecipitation and flux methods, followed by a heat-treatment process. From the X-ray diffraction patterns, all particles were found to be cubic spinel after flux treatment. The tetragonalization process was carried out by a heat-treatment process in air, where the temperature was varied between 700 °C and 900 °C, followed by furnace cooling. We confirmed that the ideal temperature for the tetragonalization of both CuFe2O4 and (Cu,Co)Fe2O4 is 900 °C. The obtained single-phase tetragonal spinel-structured CuFe2O4 and (Cu,Co)Fe2O4 particles indicate tetragonal distortion as a consequence of the JT effect of the Cu2+ ions. The results of saturation magnetization suggest that most of the divalent ions are in the B sites. The lengthening of the c-axis due to the JT effect increased the coercivity of the CuFe2O4 and (Cu,Co)Fe2O4 particles during the cubic–tetragonal phase transformation. The tetragonal (Cu,Co)Fe2O4 particles showed a saturation magnetization of 26 emu/g and a coercivity of 2200 Oe.
Autors: Hawa Latiff;Mikio Kishimoto;Sonia Sharmin;Eiji Kita;Hideto Yanagihara;Takashi Nakagawa;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Enhanced gm and fT With High Johnson’s Figure-of-Merit in Thin Barrier AlGaN/GaN HEMTs by TiN-Based Source Contact Ledge
Abstract:
A high combination of transconductance (), current gain cutoff frequency () and three terminal breakdown voltage was achieved using thin barrier AlGaN/GaN HEMTs and TiN-based source contact ledge. The sheet resistance is effectively reduced, whereas the peak extrinsic trans-conductance is improved by 24% from 334 to 415 mS/mm. The thin barrier AlGaN/GaN HEMTs with TiN-based source ledge exhibit a maximum drain current of 1096 mA/mm, a three-terminal off-state breakdown voltage (BV) of 151 V, a high current-gain cutoff frequency of 69 GHz, and a high power-gain cutoff frequency of 110 GHz. No significant drain current collapse was observed on thin barrier AlGaN/GaN HEMTs with TiN-based source contact ledge. The uniform characteristic over a wide range of bias condition is achieved by using the TiN-based source contact ledge devices. The calculated Johnson’s figures of merit (J-FOM = BV) is 10.4 THz-V, which is the highest record so far for T-gate SiN passivation AlGaN/GaN HEMTs without source field plate.
Autors: Ling Yang;Minhan Mi;Bin Hou;Hengshuang Zhang;Jiejie Zhu;Qing Zhu;Yang Lu;Meng Zhang;Yunlong He;Lixiang Chen;Xiaowei Zhou;Ling Lv;Xiaohua Ma;Yue Hao;
Appeared in: IEEE Electron Device Letters
Publication date: Nov 2017, volume: 38, issue:11, pages: 1563 - 1566
Publisher: IEEE
 
» Enhanced Magnetic Field Sensitivity in Magnetoelectric Composite Based on Positive Magnetostrictive/Negative Magnetostrictive/Piezoelectric Laminate Heterostructure
Abstract:
Resonance magnetoelectric (ME) responses are investigated for the ME laminate heterostructure consisting of positive magnetostrictive material FeCuNbSiB, negative magnetostrictive material Ni and piezoelectric material PZT-8. On one hand, both a built-in magnetic field induced by the strong magnetic interactions between positive magnetostrictive and negative magnetostrictive materials and an intrinsic anisotropic field with obvious hysteresis and remnant magnetization in Ni layer result in a large zero-biased ME effect. The corresponding zero-biased ME voltage coefficient reaches 10.12 V/Oe (126.5 V/cm Oe), which is about 3 times larger than that of traditional Ni/PZT-8 (NP) laminate. On the other hand, the additional stress produced by the high magnetic permeability FeCuNbSiB layer enhances the magnetostriction of Ni layer and ME response. The corresponding maximum ME voltage coefficient (dVME/dHac) is 12.09 V/Oe (150.87 V/cm Oe) at bias magnetic field Oe. It is further found that even a step change of ac magnetic field less than 10−10 T can be clearly distinguished by the proposed ME composite. The value of ME voltage sensitivity to dc magnetic fields (dVME/dH reaches ~76.7 mV/Oe at Oe and Oe. Correspondingly, the proposed laminate heterostructure is able to possess both strong ac and dc magnetic field sensitivities.
Autors: Lei Chen;Yao Wang;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Enhanced Magnetic Properties of Spark Plasma Sintered (La/Ce)–Fe–B Magnets
Abstract:
La substitution for Ce inhibits the growth of the CeFe2 phase and promotes the formation of the single 2:14:1 phase, leading to an improvement in the magnetic properties of melt-spun (La/Ce)3Fe14B ribbons. Among which, the (La0.3Ce0.7)3Fe14B ribbon produced a high remanence of 6.86 kG, a coercivity of 5.51 kOe, and a maximum energy product (BH)max of 7.68 MGOe. After spark plasma sintering, the compacted (La0.3Ce0.7)3Fe14B magnet with good remanence and coercivity was successfully prepared, and these properties were enhanced to 5.14 kG and 5.60 kOe, respectively, leading to an energy product of 4.59 MGOe for the magnet with 5 wt % NdCu addition.
Autors: Q. M. Lu;J. Niu;W. Q. Liu;M. Yue;Z. Altounian;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 3
Publisher: IEEE
 
» Enhanced Photocatalytic Activity of Core–Shell ZnFe2O4@ZnO Nanoparticles for Visible Light Photodegradation
Abstract:
A facile, efficient approach to fabricate ZnFe2O4@ZnO nanoparticles with a good core–shell structure was reported, involving the coating of successive layers of ZnO nanoparticles on a magnetic core by a sol–gel hydrothermal method at low temperatures. The as-synthesized ZnFe2O4@ZnO nanoparticles exhibited a narrow size distribution, with a typical size of 210 ± 19 nm and shell thickness of 35 nm. The ZnFe2O4@ZnO photocatalyst exhibited high photocatalytic activity for the degradation of methylene blue under solar light. Compared with ZnFe2O4, ZnFe2O4@ZnO exhibited higher photocatalytic efficiency, caused by the generation of a large number of electron–hole pairs. ZnFe2O4@ZnO exhibited excellent reusability with high photocatalytic efficiencies, indicative of its suitability for the solar photocatalytic applications.
Autors: Jun-Sik Nam;Ki Chang Nam;Kyong-Hoon Choi;Bong Joo Park;Jin-Seung Jung;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Enhanced Target Detection for HFSWR by 2-D MUSIC Based on Sparse Recovery
Abstract:
This letter proposes using the 2-D multiple-signal classification (MUSIC) based on sparse recovery (SR) to improve the target-detection capability of high-frequency surface wave radar (HFSWR). Usually, for wide-beam HFSWRs, target detection is first conducted in the range-Doppler spectrum, and bearings are then estimated by superresolution methods such as MUSIC. Unfortunately, the conventional cascaded method can easily result in unfavorable deterioration of multitarget detection when different target signals tend to become mixed in the Doppler spectrum. Moreover, sea clutter is an unwanted signal that frequently masks target signals. To enhance the detection of multiple targets and targets embedded in sea clutter, spatial–temporal joint estimation has been proposed. However, because of the lack of spatial–temporal snapshots caused by the nonstationarity of target signals, the efficiency of the estimator cannot be guaranteed. To overcome this shortcoming, multiple-measurement-vector-based SR, which has been used to solve many under-sampling problems in the past ten years, is adopted. Our approach can effectively detect a target embedded in sea clutter as well as multiple adjacent targets and distinguish them from each other. Results obtained using real data with opportunistic targets validate our approach. Therefore, the proposed 2-D SR-MUSIC approach improves target detection and outperforms conventional cascaded methods.
Autors: Zezong Chen;Chao He;Chen Zhao;Fei Xie;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 1983 - 1987
Publisher: IEEE
 
» Enhancement for High-Speed Switching of Magneto-Optic Fiber-Based Routing Using Single Magnetizing Coil
Abstract:
This paper discusses a compact and faster technique to switch magneto-optics (MO) routing systems. The new design utilizes a single coil to generate in-phase and out-of-phase magnetic fields to magnetize and demagnetize the MO material. Because of the use of high-current pMOS and nMOS transistors, along with a single coil, this new circuit enhances the switching speed and minimizes the package size. The authors have shown with experimental results that the proposed magnetic field generator circuit can produce forward and reverse magnetic fields to aid the MO material to switch faster.
Autors: Jayaprakash Selvaraj;Wei Shen Theh;Neelam Prabhu Gaunkar;Jiayu Hong;Leif H Bauer;Mani Mina;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Enhancement of the Magnetoelectric Effect in Multiferroic CoFe2O4/PZT Bilayer by Induced Uniaxial Magnetic Anisotropy
Abstract:
In this paper, we have compared magnetic, magnetostrictive, and piezomagnetic properties of isotropic and anisotropic cobalt ferrite pellets. The isotropic sample was prepared by the ceramic method while the sample exhibiting uniaxial anisotropy was made by reactive sintering using spark plasma sintering (SPS). This technique permits us to induce a magnetic anisotropy in cobalt ferrite in the direction of the applied pressure during the SPS process. Sample with uniaxial anisotropy revealed a higher longitudinal magnetostriction and piezomagnetism compared with the isotropic sample, but the transversal magnetostriction and piezomagnetism were dramatically reduced. In the case of magnetoelectric (ME) layered composite, the ME coefficient is directly related to the sum of the longitudinal and transversal piezomagnetic coefficients. These two coefficients being opposite in sign, the use of material exhibiting high longitudinal and low transversal piezomagnetic coefficient (or vice versa) in ME devices is expected to improve the ME effect. Hence, ME bilayer devices were made using isotropic and anisotropic cobalt ferrite stuck with a lead zirconate titanate layer. ME measurements at low frequencies revealed that bilayer with anisotropic cobalt ferrite exhibits an ME coefficient three times higher than a bilayer with isotropic cobalt ferrite. We also investigated the behavior of such composites when excited at resonant frequency.
Autors: Alex Aubert;Vincent Loyau;Frédéric Mazaleyrat;Martino LoBue;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Enhancement of Transient Two-States Characteristics in Metal-Insulator-Semiconductor Structure by Thinning Metal Thickness
Abstract:
In this work, the Al/SiO2/p-Si metal-insulator-semiconductor structures with various metal thicknesses were fabricated. The charging/discharging transient current behaviors during sweeping or switching the voltages have been studied. By thinning down partial portion of the gate metal to 10 nm, the steady state leakage current was found decreased because the high resistivity of the ultrathin metal causing lower fringing field effect. Also, the transient currents were found enhanced. The reasons were that there were minority carriers under the ultrathin metal contributing to the transient currents. The above properties make the device having better volatile memory characteristics.
Autors: Kuan-Hao Tseng;Chien-Shun Liao;Jenn-Gwo Hwu;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 1011 - 1015
Publisher: IEEE
 
» Enhancing Capacity in Compact MIMO-OFDM Systems With Frequency-Selective Matching
Abstract:
Mutual coupling among receive antennas can profoundly reduce capacity in multiple-input, multiple-output (MIMO) systems. Prior work has shown that these losses can often be significantly reduced by using sophisticated antenna matching at the receiver. However, previous studies have focused exclusively on frequency non-selective matching, and rely on assumptions that are valid only for small bandwidths. In this paper, we consider the capacity of broadband MIMO-OFDM systems with coupled receive antennas. We present upper and lower bounds on the best capacity that can be achieved by physically realizable, frequency-selective antenna matching. The upper and lower bounds coincide for most antenna configurations considered in the examples, and thus determine the performance of capacity-optimal matching. These results suggest that frequency-selective matching can significantly increase capacity in the presence of strong coupling. Moreover, these gains can be achieved by a simple class of matching networks that are easily realized in hardware.
Autors: Lopamudra Kundu;Brian L. Hughes;
Appeared in: IEEE Transactions on Communications
Publication date: Nov 2017, volume: 65, issue:11, pages: 4694 - 4703
Publisher: IEEE
 
» Enhancing Energy Efficiency via Cooperative MIMO in Wireless Sensor Networks: State of the Art and Future Research Directions
Abstract:
CMIMO is an effective approach to increase throughput and energy efficiency through the collaboration of individual antennas working together as a virtual multi-antenna system. Several CMIMO strategies have been propounded as major candidates for achieving green communications in wireless sensor networks. Compared to conventional MIMO, CMIMO provides significant gains in terms of flexibility. Recently, more advanced cooperation strategies have been proposed to improve the performance of CMIMO by using emerging techniques such as spatial modulation and coding. Although some breakthroughs have been made in this area, the problem of how to accurately adopt these emerging techniques to model CMIMO is far from being fully understood. This article surveys several state-of-the-art CMIMO models for different scenarios, including data aggregated, multihop-based, and clustered schemes. Moreover, it discusses the implementation of CMIMO techniques, which are expected to be candidate techniques for green communications in modern applications. In the implementation, the trade-offs between energy efficiency and spectral efficiency, quality of service, fairness, and security are discussed. Several simulation results are given to show how emerging techniques in CMIMO design can lead to energy efficiency enhancement. Finally, some challenges and open issues that present future research directions are discussed.
Autors: Yuyang Peng;Fawaz Al-Hazemi;Raouf Boutaba;Fei Tong;Il-Sun Hwang;Chan-Hyun Youn;
Appeared in: IEEE Communications Magazine
Publication date: Nov 2017, volume: 55, issue:11, pages: 47 - 53
Publisher: IEEE
 
» Enhancing MongoDB with Purpose-Based Access Control
Abstract:
Privacy has become a key requirement for data management systems. Nevertheless, NoSQL datastores, namely highly scalable non relational database management systems, which often support data management of Internet scale applications,still do not provide support for privacy policies enforcement. With this work, we begin to address this issue, by proposing an approach for the integration of purpose based policy enforcement capabilities into MongoDB, a popular NoSQL datastore. Our contribution consists of the enhancement of the MongoDB role based access control model with privacy concepts and related enforcement monitor. The proposed monitor is easily integrable into any MongoDB deployment through simple configurations. Experimental results show that our monitor enforces purpose-based access control with low overhead.
Autors: Pietro Colombo;Elena Ferrari;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Nov 2017, volume: 14, issue:6, pages: 591 - 604
Publisher: IEEE
 
» Enhancing Responsivity and Detectevity of Si-ZnO Photodetector With Growth of Densely Packed and Aligned Hexagonal Nanorods
Abstract:
High-performance photodiodes are desirable for ultrahigh speed optical communication and highresolution optical instrumentation. This paper reports both theoretical and experimental optimization approaches for low-cost chemothermal growth of hexagonal nanorods on Si-ZnO heterojunction. The alignments of nanorods were made by controlling the etching rate with the addition of 2% isopropyl alcohol during the process. The formation of nanorods were found to be linear, densely packed, and uniformly distributed on ZnO thin film as seen from SEM images and X-ray Diffraction (XRD) pattern. The X-ray Photoelectron Spectroscopy result shows the absence of carbon contamination and confirms the elemental composition of ZnO. The current–voltage measurement confirms ohmic junction between the nanostructure and ZnO thin film enhancing the increase of photocurrent, which provides high responsivity. The proposed fabrication process opens up the possibility of realization of low-cost, high-performance, and future flexible optoelectronics sensor circuitry.
Autors: Santanu Maity;Deboraj Muchahary;Partha Pratim Sahu;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 939 - 945
Publisher: IEEE
 
» Envelope Control for Four-Wheel Independently Actuated Autonomous Ground Vehicle Through AFS/DYC Integrated Control
Abstract:
This paper proposes an envelope control framework for four-wheel independently actuated autonomous ground vehicle (AGV) to regulate it on desired path and simultaneously control it to the driving limits. The envelope control framework is achieved based on the integrated control of active front-wheel steer and direct yaw-moment control. In a speed controller, the G-G diagram is used to describe the driving limits on each path segment. The desired traction and braking force is calculated according to the G-G diagram and desired path. In a path-following controller, a feedforward–feedback lateral controller is designed to calculate the desired steering angle to follow the desired path. In a yaw-moment controller, the β–r phase portraits are utilized to describe the handling limits. The yaw-moment controller aims at keeping the AGV from losing stability in limit driving, which is calculated through a sliding mode controller and provided by the independent motors actuation. Through an independent driving technique, the tyre cornering stiffness is estimated online based on the predefined Magic Formula model to improve the controller's robustness. An autonomous Formula Student racecar developed by the authors is used as testbed. The autonomous driving experiments on racetrack validate the efficiency of the proposed controller.
Autors: Jun Ni;Jibin Hu;Changle Xiang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 9712 - 9726
Publisher: IEEE
 
» Epitaxial ScAlN Etch-Stop Layers Grown by Molecular Beam Epitaxy for Selective Etching of AlN and GaN
Abstract:
Although selective dry etches exist for GaN, it is difficult to selectively etch AlN in heterostructures with other conventional III-N epitaxial materials. The reduction in etch rate resulting from the addition of 2%–16% scandium to ScxAl1–xN in conventional Cl2/BCl3/Ar inductively coupled plasma etching is presented. Smooth, epitaxial ScxAl1–xN layers are grown by RF-plasma-assisted molecular beam epitaxy directly on 4H-SiC substrates. The etch selectivity with respect to AlN is as high as 10.6 and 11.2 for and 0.16, respectively, allowing ScxAl1–xN to act as an etch-stop layer with minimal misfit strain when grown within either AlN or GaN based heterostructures.
Autors: Matthew T. Hardy;Brian P. Downey;David J. Meyer;Neeraj Nepal;David F. Storm;D. Scott Katzer;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 475 - 479
Publisher: IEEE
 
» Equalization Method of the Wireless Power Transfer in an Electronic Shelf Label Power Supply System
Abstract:
In a wireless power transmission device that drives multiple power outputs for electronic shelf labels (ESLs), we propose a novel rail transformer design for use with a 50/60 Hz power supply. By periodically short circuiting the receiving coils located closest to the transmitting coil, we experimentally verified that power can be transmitted to each ESL in a significantly uniform fashion. We expect the present approach with periodically switched receiver coils to be much more convenient, reliable, and flexible than our previous method of physically adjusting the air gaps between coils. In verification experiments, the output power of three receiving coils in a prototype was equalized at a level of approximately 60 mW. Without periodic switching, the output power of the center receiving coil only reached 40 mW, whereas, the receiving coils closest to the transmitting coils reached an output level of 80 mW, with output power fluctuating by approximately 49%. This paper demonstrates an effective design strategy for wireless power transfer devices.
Autors: Yinggang Bu;Subhas Chandra Mukhopadhyay;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Equilibrium Analysis of Markup Pricing Strategies Under Power Imbalance and Supply Chain Competition
Abstract:
This study uses a game-theory-based analytical model to examine the consequences of two markup pricing schemes, fixed-dollar markup and percentage markup, in a supply chain-to-chain competition setting with power imbalance between dominant retailers. Our results show that the equilibrium pricing strategy depends on the level of supply chain-to-chain competition. Specifically, if the level of supply chain competition is not sufficiently high, the equilibrium pricing strategy for the two retailers will be the one in which both retailers choose to adopt the percentage markup pricing policy, i.e., the [PP] strategy. Unfortunately, this equilibrium will lead the retailers into the prisoner's dilemma in some common situations. However, if the level of competition is extremely high, the equilibrium pricing strategy will be that where the leader (Retailer 1) chooses the percentage markup pricing policy and the follower (Retailer 2) selects the fixed-dollar markup pricing policy, i.e., the [PF] strategy. This equilibrium pricing strategy always hurts Manufacturer 1, but might benefit Manufacturer 2 when the level of competition exceeds a certain threshold. From the perspective of the end-consumers, they prefer the level of competition to be kept below a certain threshold such that the [PP] strategy becomes the equilibrium pricing strategy because this equilibrium leads to the lowest retail prices. Furthermore, our results show that Retailer 1 suffers a first-mover disadvantage even under a linear demand curve, and this situation cannot be alleviated by abandoning its price-leader position to share power equally with Retailer 2.
Autors: Yao-Yu Wang;Zhongsheng Hua;Jian-Cai Wang;Fujun Lai;
Appeared in: IEEE Transactions on Engineering Management
Publication date: Nov 2017, volume: 64, issue:4, pages: 464 - 475
Publisher: IEEE
 
» Ernst Werner Von Siemens and the Early Evolution and Diffusion of Electric Telegraphy [Scanning Our Past]
Abstract:
The technology of electric telegraphy that revolutionized long-distance communication and established the groundwork for later innovations, such as telephone, fax machine, and internet, emerged in the 1830s and 1840s thanks to the work of many men of science and technology around the world. In 1799, Alessandro Volta’s invention of reliable storage electric currents which allowed their use in controlled conditions, and the demonstration two decades later of a connection between electricity and magnetism by Hans Christian Oersted, supported the experimentation which led to a communication system by which electric signals were transmitted over a wire laid between stations.
Autors: Simón Reif-Acherman;
Appeared in: Proceedings of the IEEE
Publication date: Nov 2017, volume: 105, issue:11, pages: 2274 - 2284
Publisher: IEEE
 
» Errata to “Using Wearable Technology to Generate Objective Parkinson’s Disease Dyskinesia Severity Score: Possibilities for Home Monitoring”
Abstract:
In the above paper [1], the affiliation for M. Delrobaei was listed incorrectly. The affiliation should have appeared as follows:
Autors: Mehdi Delrobaei;Navid Baktash;Greydon Gilmore;Kenneth McIsaac;Mandar Jog;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2214 - 2214
Publisher: IEEE
 
» Erratum to "Low-Cost Collaborative Mobile Charging for Large-Scale Wireless Sensor Networks"
Abstract:
The authors of "Low-Cost Collaborative Mobile Charging for Large-Scale Wireless Sensor Networks" which appeared in August issue of this journal [ibid., vol. 16, no. 8, pp. 2213–2227, Aug. 2017] would like to correct a typo that occurred in Fig. 1. The numbers above the X axis were wrong. The corrected Fig. 1 is provided
Autors: Tang Liu;Baijun Wu;Hongyi Wu;Jian Peng;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3278 - 3278
Publisher: IEEE
 
» Error Performance Optimization Using Logarithmic Barrier Function in Molecular Nanonetworks
Abstract:
The performance of a molecular signal detector relies on selected value of the detection threshold. In fact, arbitrary choice of detection threshold would increase either the probability of miss detection or the probability of false alarm. Thereby, an appropriate value of detection threshold is required in order to optimize the error performance of a realistic diffusion-based molecular communication (DbMC) system. For this, we come up with a new approach that yields optimal value for convex optimization problem in DbMC using logarithmic barrier followed by modified Karush–Kuhn–Tucker conditions, Newton Raphson method, and finally rounding the solution to the nearest integer value. Previous works on threshold optimization in DbMC either give suboptimal solution or optimal one whereof the convergence depends on choosing the smallest interval that contains the optimal value. Numerical and simulation results reveal that our proposed methodology can provide optimal solution with utmost accuracy in few iterations.
Autors: Satish K. Tiwari;Tadi Ravi Teja Reddy;Prabhat K. Upadhyay;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2408 - 2411
Publisher: IEEE
 
» Error-Free Text Typing Performance of an Inductive Intra-Oral Tongue Computer Interface for Severely Disabled Individuals
Abstract:
For severely paralyzed individuals, alternative computer interfaces are becoming increasingly essential for everyday life as social and vocational activities are facilitated by information technology and as the environment becomes more automatic and remotely controllable. Tongue computer interfaces have proven to be desirable by the users partly due to their high degree of aesthetic acceptability, but so far the mature systems have shown a relatively low error-free text typing efficiency. This paper evaluated the intra-oral inductive tongue computer interface (ITCI) in its intended use: Error-free text typing in a generally available text editing system, Word. Individuals with tetraplegia and able bodied individuals used the ITCI for typing using a MATLAB interface and for Word typing for 4 to 5 experimental days, and the results showed an average error-free text typing rate in Word of 11.6 correct characters/min across all participants and of 15.5 correct characters/min for participants familiar with tongue piercings. Improvements in typing rates between the sessions suggest that typing ratescan be improved further through long-term use of the ITCI.
Autors: Lotte N. S. Andreasen Struijk;Bo Bentsen;Michael Gaihede;Eugen R. Lontis;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Nov 2017, volume: 25, issue:11, pages: 2094 - 2104
Publisher: IEEE
 
» eSES: Enhanced Simple Energy Saving for LTE HeNBs
Abstract:
This letter proposes enhanced simple energy saving (eSES), a simple yet novel scheme, that turns off the RF module of inactive low-power LTE Home evolved Node B (HeNBs), and accurately wakes up these dormant HeNBs when there are connection requests. The eSES does not modify the 3rd Generation Partnership Project (3GPP) specifications, and can co-exist with other HeNBs that do not exercise the eSES. We show that the eSES effectively saves the energy consumption of a dormant HeNB at the cost of moderately increasing the connection time of the first call request to the HeNB.
Autors: Yi-Bing Lin;Li-Chang Wang;Wei-Cheng Chen;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2520 - 2523
Publisher: IEEE
 
» Estimation of Basis Line-Integrals in a Spectral Distortion-Modeled Photon Counting Detector Using Low-Rank Approximation-Based X-Ray Transmittance Modeling: K-Edge Imaging Application
Abstract:
Photon counting detectors (PCDs) provide multiple energy-dependent measurements for estimating basis line-integrals. However, the measured spectrum is distorted from the spectral response effect (SRE) via charge sharing, K-fluorescence emission, and so on. Thus, in order to avoid bias and artifacts in images, the SRE needs to be compensated. For this purpose, we recently developed a computationally efficient three-step algorithm for PCD-CT without contrast agents by approximating smooth X-ray transmittance using low-order polynomial bases. It compensated the SRE by incorporating the SRE model in a linearized estimation process and achieved nearly the minimum variance and unbiased (MVU) estimator. In this paper, we extend the three-step algorithm to K-edge imaging applications by designing optimal bases using a low-rank approximation to model X-ray transmittances with arbitrary shapes (i.e., smooth without the K-edge or discontinuous with the K-edge). The bases can be used to approximate the X-ray transmittance and to linearize the PCD measurement modeling and then the three-step estimator can be derived as in the previous approach: estimating the x-ray transmittance in the first step, estimating basis line-integrals including that of the contrast agent in the second step, and correcting for a bias in the third step. We demonstrate that the proposed method is more accurate and stable than the low-order polynomial-based approaches with extensive simulation studies using gadolinium for the K-edge imaging application. We also demonstrate that the proposed method achieves nearly MVU estimator, and is more stable than the conventional maximum likelihood estimator in high attenuation cases with fewer photon counts.
Autors: Okkyun Lee;Steffen Kappler;Christoph Polster;Katsuyuki Taguchi;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2389 - 2403
Publisher: IEEE
 
» Estimation of Magnetocardiography Current Sources Using Reconstructed Magnetic Field Data
Abstract:
We propose a new method of estimating magnetocardiography (MCG) current sources using reconstructed magnetic field data. Because, our MCG sensors were arranged in a 2-D plane, they could only detect the magnetic field data generated in front of the torso, which leads to estimation of blurred source imaging from deep sources. In this paper, we reconstructed the magnetic field data that cannot be detected by the MCG sensors. The locations of the reconstructed magnetic field data were also in a 2-D plane and parallel to the sensor array. The proposed method shows that it reduced the current-source extension and enhanced the spatial resolution for deep sources. We evaluated the current-source extension and spatial resolution at R peak. The active regions of the ventricular depolarization and repolarization were obtained using time integration with the current sources estimated at QRS complex and T wave, respectively. The proposed method can estimate high spatial resolution source imaging, especially for current sources that are far from the MCG sensors.
Autors: Wenxu Sun;Koichiro Kobayashi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Estimation of Performance Metrics at Signalized Intersections Using Loop Detector Data and Probe Travel Times
Abstract:
This paper introduces a simple but practical approach that uses both loop detector data and probe travel times for computing the vehicle hours traveled (VHT), average delay, and level of service (LOS) for signalized intersections. The goal is to improve upon the state-of-the-practice method outlined in the highway capacity manual (HCM) by incorporating additional travel time measurements from probe vehicles or vehicle re-identification systems. The proposed methodology is designed to work under a variety of traffic conditions, including states of congestion in which the HCM methodology is not reliable. Our analysis is then tested using simulation of an arterial site in Arcadia, CA, USA. The results suggest that the proposed methodology performs better at the approach level than at the lane group level. Population size and probe penetration rate are two key parameters in the estimation. Either a large population size or a high penetration rate is required in order to produce reliable estimates of VHT, delay, and LOS. Results also show that the proposed methodology only requires 7% of the penetration rate to outperform the HCM methodology.
Autors: Qijian Gan;Gabriel Gomes;Alexandre Bayen;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Nov 2017, volume: 18, issue:11, pages: 2939 - 2949
Publisher: IEEE
 
» Evaluating Software Project Managers: A Multidimensional Perspective
Abstract:
A qualified and motivated project manager is a key factor in a software project’s success. Thus, getting the most out of those managers is important. Feedback is a critical part of this process. With this in mind, this article recommends the best practices for evaluating software project managers.
Autors: Lawrence Peters;Ana M. Moreno;
Appeared in: IEEE Software
Publication date: Nov 2017, volume: 34, issue:6, pages: 104 - 108
Publisher: IEEE
 
» Evaluation Method for Multidegree-of-Freedom Spherical Actuators Under Power Control
Abstract:
Multidegree-of-freedom (multi-DOF) actuators have been developed for the fields of robotics and industrial machinery. In general, an actuating system with multi-DOF is composed of single-DOF actuators, which results in large, heavy, and complicated structures. Therefore, multi-DOF actuators are expected to become a key technology to solve these problems, and various actuators have been proposed and evaluated using their own methods. However, evaluation methods for absolute comparisons of the actuators have not been proposed. In order to evaluate the characteristics of the spherical synchronous actuators under the same condition, an evaluation method based on a torque equation and singular value decomposition is proposed. The proposed method can evaluate the static torque characteristics using a torque area that is composed of torques around arbitrary axes. The effectiveness of the proposed method is verified by comparing the static torque characteristics of several spherical actuators.
Autors: Kazuaki Takahara;Katsuhiro Hirata;Noboru Niguchi;Yusuke Nishiura;Yo Sakaidani;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Evaluation Methodology for Fast Switching Cloud RAN Systems
Abstract:
The switching scheme between base band units (BBUs) and remote radio heads (RRHs) is a key point in a cloud radio access network (C-RAN). Fast BBU-RRH switching schemes will play crucial roles in future flexible C-RAN systems. In this letter, an evaluation model is proposed to analyze the performance of fast switching schemes. Based on the model, we also propose an evaluation methodology through jointly taking backlogs, idle resources, and switching costs into account. The evaluation methodology provides guidance on future design for fast switching schemes. Finally, the effectiveness of the proposed methodology is validated by simulation results.
Autors: Yaxin Wang;Xin Zhang;Dacheng Yang;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2404 - 2407
Publisher: IEEE
 
» Evaluation of a Heterogeneous Multicore Architecture by Design and Test of an OFDM Receiver
Abstract:
This paper presents an evaluation of a Heterogeneous Multicore Architecture (HMA) by implementing Orthogonal Frequency-Division Multiplexing (OFDM) receiver blocks as designs for the test of functionality. OFDM receiver consists of computationally intensive and general-purpose processing tasks that can provide maximum coverage to test and evaluate a massively-parallel as well as a general-purpose platform like the HMA. The blocks of the receiver are primarily designed by crafting template-based Coarse-Grained Reconfigurable Array (CGRA) devices and then arranging them in a sequence over a Network-on-Chip (NoC) structure along with a few RISC cores for complete OFDM processing. The OFDM blocks such as Fast Fourier Transform (FFT) and Time Synchronization are computationally intensive and require parallel processing. The OFDM receiver also contains tasks such as frequency offset estimation which require the processing of Taylor series and CORDIC algorithms that are serial in nature. Such a combination of serial and parallel algorithms can perform a thorough exploration and evaluation of almost all the design features of an HMA. The OFDM implementation has led to scale CGRAs to different dimensions, instantiate Processing Elements (PEs) as multiple arithmetic resources and to establish almost all possible ways of PE interconnections. It further explores time-multiplexed patterns for data placement in the CGRA memories. Nevertheless, the data can also be exchanged among different nodes over NoC structure simultaneously and independently by using direct memory access devices. In this experimental work, the performance of each CGRA, the collective performance of the whole platform and the NoC traffic are recorded in terms of the number of clock cycles and several high-level performance metrics. Today's HMAs are generally over or under resourced for the applications that they are designed for and thus not an optimal choice for the end user. Apart from t- e interesting comparisons to the other state-of-the-art, our experimental setup has provided important insight and guidelines that the designers can use to implement near-optimal solutions for their target applications.
Autors: Sajjad Nouri;Waqar Hussain;Jari Nurmi;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Nov 2017, volume: 28, issue:11, pages: 3171 - 3187
Publisher: IEEE
 
» Evaluation of Cable SGEMP Response Using Monte Carlo and Finite-Difference Time-Domain Methods
Abstract:
In this paper, the system-generated electromagnetic pulse (SGEMP) response generated on the shielded cable after X-ray irradiation in laser inertial confinement fusion facility is studied by the Monte Carlo and finite-difference time-domain (FDTD) method. A layered cable model is established according to the radiation environment in the target chamber of the SG-III laser facility, the Monte Carlo software MCNP5 is used to calculate the number of deposited charges, and a program is developed based on the FDTD method to calculate the electromagnetic field in the dielectric layer. Finally, the current response on the cable conductor is obtained using Ampere’s circuit law. The results showed that the peak current response on the cable with a length of 1 m is as large as 1.26 A with a frequency range of 0–5 GHz. Furthermore, some important parameters, such as the X-ray fluence, pulsewidth, X-ray energy, cable material, thickness of the shielding layer, and length of the cable, all have effects on the cable SGEMP.
Autors: Zhiqian Xu;Cui Meng;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Nov 2017, volume: 64, issue:11, pages: 2829 - 2836
Publisher: IEEE
 
» Evaluation of core-continuity-constrained ROADMs for flex-grid/MCF optical networks
Abstract:
To effectively keep pace with the global IP traffic growth forecasted in the years to come, flex-grid over multi-core fiber (MCF) networks can bring superior spectrum utilization flexibility, as well as bandwidth scalability far beyond the non-linear Shannon's limit. In such a network scenario, however, full node switching re-configurability will require enormous node complexity, pushing the limits of current optical device technologies with prohibitive capital expenditures. Therefore, cost-effective node solutions will most probably be the key enablers of flex-grid/MCF networks, at least in the short- and mid-term future. In this context, this paper proposes a cost-effective reconfigurable optical add/drop multiplexer (ROADM) architecture for flex-grid/MCF networks, called CCC-ROADM, which reduces technological requirements (and associated costs) in exchange for demanding core continuity along the end-to-end communication. To assess the performance of the proposed CCC-ROADM in comparison with a fully flexible ROADM (i.e., a fully non-blocking ROADM, called FNB-ROADM in this work) in large-scale network scenarios, a novel lightweight heuristic to solve the route, modulation, core, and spectrum assignment problem in flex-grid/MCF networks is presented in this work, whose goodness is successfully validated against optimal ILP formulations previously proposed for the same goal. The obtained numerical results in a significant number of representative network topologies with different MCF configurations of 7, 12, and 19 cores show almost identical network performance in terms of maximum network throughput when deploying CCC-ROADMs versus FNB-ROADMs, while decreasing network capital expenditures to a large extent.
Autors: F.-J. Moreno-Muro;R. Rumipamba-Zambrano;P. Pavón-Marino;J. Perelló;J. M. Gené;S. Spadaro;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Nov 2017, volume: 9, issue:11, pages: 1041 - 1050
Publisher: IEEE
 
» Evaluation of Correlation Between Orientation of Y3Fe5O12 (YIG) Thin Film and Spin Seebeck Effect
Abstract:
We found that the orientation of the magnetic material yttrium–iron–garnet (YIG) depends on the type of substrate. The orientation of YIG was evaluated using an orientation index. We obtained experimental results suggesting that the orientation of YIG is related to the saturation value of the generated voltage by the spin Seebeck effect and the diffusion length of the spin current. The diffusion length of the spin current is proportional to the orientation index.
Autors: Atsushi Yamamoto;Makoto Arai;Tetsuya Takimoto;Masatoshi Itoh;Shizutoshi Ando;Shigeru Saito;Takayuki Kawahara;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Evaluation of Exchange Stiffness From Temperature-Dependent Magnetization in ZnFe2O4 Thin Films
Abstract:
Nano-crystalline magnetic ZnFe2O4 thin films were deposited in oxygen atmosphere at different substrate temperatures (TS) on amorphous quartz substrate by pulsed laser deposition technique. The TS = 350 °C film was also annealed at different temperatures in air. X-ray diffraction patterns confirmed that all the samples were cubic spinel and the average grain size of the films increased with increasing TS and annealing temperatures (TA). Spontaneous magnetization at different temperature was obtained from the – loops. The temperature dependence of magnetization data was fit using Bloch’s law. The value of exchange stiffness constant (D) was calculated using the fit values of Bloch’s constant. The obtained D values were found to gradually decrease with the increase of average grain size.
Autors: B. N. Sahu;R. Prabhu;N. Venkataramani;Shiva Prasad;R. Krishnan;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Evaluation of Macro Diversity Gain in Long Range ALOHA Networks
Abstract:
Macro reception diversity is a capability allowing a packet to be received by several base stations. In this letter, we propose a simple but accurate analytical model to estimate the macro diversity gain in pure and slotted ALOHA wireless networks. The proposed model takes into account Rayleigh fading, shadowing, and capture effect. We obtain simple closed-form formulas for the network packet loss rate. We find that systems with macro reception diversity can benefit from shadowing. With path loss exponent 4, packet loss rate constraint 10% and 8 dB shadowing, the capacity of pure ALOHA with macro diversity is at least 2 times as much as that in systems in which a device transmits only to the best base station.
Autors: Qipeng Song;Xavier Lagrange;Loutfi Nuaymi;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2472 - 2475
Publisher: IEEE
 
» Evaluation of Preventive Maintenance Segregation: A Multi Factorial Study
Abstract:
Recently, several papers on preventive maintenance (PM) have shown that segregation of PM’s can be beneficial when it comes to improving factory performance. However, these were limited to either cases of equal PM segregation and/or without consideration of other factors and operating conditions such as incurred setup or the number of tools in the toolset. In this paper, we extend previous work in this area in two major respects. First, we consider the more realistic case of PM segregation into equal or unequal portions and second, we evaluate the impact of PM segregation under various operating conditions via simulation. Our simulation experiments provide insight and guidelines for practitioners in planning the PM activity such that the overall performance is improved.
Autors: Adar A. Kalir;Kosta Rozen;James R. Morrison;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 508 - 514
Publisher: IEEE
 
» Event-Triggered Global Robust Output Regulation for a Class of Nonlinear Systems
Abstract:
This note studies the global robust output regulation problem for a class of nonlinear systems by an output-based event-triggered control law. First, we convert the problem into the event-triggered global robust stabilization problem of a well-defined augmented system based on the internal model approach. Then, we design an output-based event-triggered control law together with an output-based event-triggered mechanism to solve the stabilization problem, which in turn leads to the solution to the original problem by an output-based event-triggered control law. Finally, we illustrate our approach by an example.
Autors: Wei Liu;Jie Huang;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5923 - 5930
Publisher: IEEE
 
» Event-Triggered State Estimation: An Iterative Algorithm and Optimality Properties
Abstract:
This paper investigates the optimal design of event-triggered estimation for linear systems. The synthesis approach is posed as a team decision problem where the decision makers are given by the event trigger and the estimator. The event-trigger decides upon its available measurements whether the estimator shall obtain the current state information by transmitting it through a resource constrained channel. The objective is to find the optimal tradeoff between the mean square estimation error and the expected number of transmissions over a finite horizon. After deriving basic characteristics of the optimal solution, we propose an iterative algorithm that alternates between optimizing one decision maker while fixing the other and vice versa. By analyzing the dynamical behavior of the iterative method, it is shown that the algorithm converges to a symmetric threshold policy for first-order systems if the statistics of the uncertainties are even and unimodal. In the case of bimodal distributions, we show numerically that the iterative method may find asymmetric threshold policies that outperform symmetric rules.
Autors: Adam Molin;Sandra Hirche;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5939 - 5946
Publisher: IEEE
 
» Everything You Wanted to Know About PUFs
Abstract:
In typical cryptographic applications, the secret keys are stored in volatile or nonvolatile memory (NVM). In the latter case, they remain in memory and can be retrieved even when the power is turned off. Even volatile memory is vulnerable to attacks if one has physical access to it. Thus the traditional approaches to key storage are not favored, especially in high-security applications.
Autors: Shital Joshi;Saraju P. Mohanty;Elias Kougianos;
Appeared in: IEEE Potentials
Publication date: Nov 2017, volume: 36, issue:6, pages: 38 - 46
Publisher: IEEE
 
» Evolution and Impact of Defects in a p-Channel CCD After Cryogenic Proton-Irradiation
Abstract:
The p-channel charge coupled devices (CCDs) have been shown to display improved tolerance to radiation-induced charge transfer inefficiency when compared with n-channel CCDs. However, the defect distribution formed during irradiation is expected to be temperature dependent due to the differences in lattice energy caused by a temperature change. This has been tested through defect analysis of two p-channel e2v CCD204 devices, one irradiated at room temperature and one at a cryogenic temperature (153 K). Analysis is performed using the method of single trap pumping. The dominant charge trapping defects at these conditions have been identified as the donor level of the silicon divacancy and the carbon interstitial defect. The defect parameters are analyzed both immediately postirradiation and following several subsequent room-temperature anneal phases up until a cumulative anneal time of approximately 10 months. We have also simulated charge transfer in an irradiated CCD pixel using the defect distribution from both the room-temperature and cryogenic case, to study how the changes affect imaging performance. The results demonstrate the importance of cryogenic irradiation and annealing studies, with large variations seen in the defect distribution when compared to a device irradiated at room-temperature, which is the current standard procedure for radiation-tolerance testing.
Autors: Daniel Wood;David J. Hall;Jason Gow;Jesper Skottfelt;Neil J. Murray;Konstantin Stefanov;Andrew D. Holland;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Nov 2017, volume: 64, issue:11, pages: 2814 - 2821
Publisher: IEEE
 
» Evolution of Surface Plasmon Supermodes in Metal-Clad Microwire and Its Potential for Biosensing
Abstract:
A finite-element method based on the vector H-field formulation in conjunction with perturbation techniques is used to study metal-clad microwire waveguides for bio-sensing applications. Sensors are designed to detect DNA hybridization through the change of the effective index and attenuation constant of the waveguide structure. The key parameters, such as effective index, loss coefficient, and spot sizes, are presented and potential sensor applications are discussed.
Autors: Nina Siti Aminah;Christos Themistos;Rahmat Hidayat;Mitra Djamal;B. M. A. Rahman;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4684 - 4691
Publisher: IEEE
 
» Evolutionary Approach to Solve a Novel Time-Domain Cavity Problem
Abstract:
The problem of forced oscillations in a cavity filled with a dynamic plasma is solved in the time domain in compliance with the principle of causality. Interaction of the plasma and the cavity field is driven by the motion equation where the field is present in the Lorentz force standing at its right-hand side. The solution has a form of the modal expansions. Every term herein is a product of two multipliers. One is the vector element of the modal basis dependent on coordinates only. The basis is obtained as an eigenvector set of a self-adjoint operator specially selected from Maxwell’s equations. The operator is specified as a merger of the differential procedure and the boundary conditions over perfectly conducting cavity surface. The basis elements are derived with their physical dimensions, i.e., volt per meter and ampere per meter. The other factor is a scalar dimension-free time-dependent modal amplitude. A system of evolutionary equations (i.e., with time derivative) for the modal amplitudes is derived and solved explicitly under the initial conditions. The problem is solved in the Hilbert space of real-valued functions of coordinates and time.
Autors: Fatih Erden;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Nov 2017, volume: 65, issue:11, pages: 5918 - 5931
Publisher: IEEE
 
» Exact Synthesis of Majority-Inverter Graphs and Its Applications
Abstract:
We propose effective algorithms for exact synthesis of Boolean logic networks using satisfiability modulo theories (SMTs) solvers. Since exact synthesis is a difficult problem, it can only be applied efficiently to very small functions, having up to six variables. Key in our approach is to use majority-inverter graphs (MIGs) as underlying logic representation as they are simple (homogeneous logic representation) and expressive (contain AND/OR-inverter graphs) at the same time. This has a positive impact on the problem formulation: it simplifies the encoding as SMT constraints and also allows for various techniques to break symmetries in the search space due to the regular data structure. Our algorithm optimizes with respect to the MIG’s size or depth and uses different ways to encode the problem and several methods to improve solving time, with symmetry breaking techniques being the most effective ones. We discuss several applications of exact synthesis and motivate them by experiments on a set of large arithmetic benchmarks. Using the proposed techniques, we are able to improve both area and delay after lookup table (LUT)-based technology mapping beyond the current results achieved by state-of-the-art logic synthesis algorithms.
Autors: Mathias Soeken;Luca Gaetano Amarù;Pierre-Emmanuel Gaillardon;Giovanni De Micheli;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Nov 2017, volume: 36, issue:11, pages: 1842 - 1855
Publisher: IEEE
 
» Exchange Bias Induced by the Spin Glass-Like Surface Spins in Sputter Deposited Fe3O4 Thin Films
Abstract:
The exchange bias in the reactive sputtered polycrystalline Fe3O4 thin films of thicknesses 50 and 150 nm is studied. X-ray diffraction, laser Raman, and selected area electron diffraction studies confirm the formation of the Fe3O4 single phase. The high-resolution transmission electron microscope images show the presence of well-defined crystallites. The presence of the exchange bias effect is mainly due to the existence of a significant exchange coupling between the core spins and the spin glass-like surface spins of the grains. The temperature dependence of the magnitude of the exchange bias field shows two exponential regimes of which the lower temperature regime corresponds to the spin freezing effect below 50 K. The first magnetization curves measured after zero field cooling show S-shape below the spin freezing temperature. The presence of superparamagnetism and spin freezing has been investigated through the field cooled (FC) and zero FC magnetization measurements. Temperature dependence of coercivity also indicates the spin freezing effect. Hence, the observed large exchange bias of the samples at lower temperatures is due to the freezing of the surface spins.
Autors: P. V. Muhammed Shameem;Laxman Mekala;M. Senthil Kumar;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Experiencing the Sights, Smells, Sounds, and Climate of Southern Italy in VR
Abstract:
This article explores what it takes to make interactive computer graphics and VR attractive as a promotional vehicle, from the points of view of tourism agencies and the tourists themselves. The authors exploited current VR and human-machine interface (HMI) technologies to develop an interactive, innovative, and attractive user experience called the Multisensory Apulia Touristic Experience (MATE). The MATE system implements a natural gesture-based interface and multisensory stimuli, including visuals, audio, smells, and climate effects.
Autors: Vito M. Manghisi;Michele Fiorentino;Michele Gattullo;Antonio Boccaccio;Vitoantonio Bevilacqua;Giuseppe L. Cascella;Michele Dassisti;Antonio E. Uva;
Appeared in: IEEE Computer Graphics and Applications
Publication date: Nov 2017, volume: 37, issue:6, pages: 19 - 25
Publisher: IEEE
 
» Experimental Analysis of Nonlinear Impairments in Fibre Optic Transmission Systems up to 7.3 THz
Abstract:
An effective way of increasing the overall optical fibre capacity is by expanding the bandwidth used to transmit signals. In this paper, the impact of expanding the transmission bandwidth on the optical communication system is experimentally studied using the achievable rates as a performance metric. The tradeoffs between the use of larger bandwidths and higher nonlinear interference (NLI) noise is experimentally and theoretically analyzed. The growth of NLI noise is investigated for spectral bandwidths from 40 GHz up to 7.3 THz using 64-QAM and Nyquist pulse-shaping. Experimental results are shown to be in line with the predictions from the Gaussian-noise model showing a logarithmic growth in NLI noise as the signal bandwidth is extended. A reduction of the information rate of only 10% was found between linear and nonlinear transmission across several transmission bandwidths, increasing up to 7.3 THz. Finally, the power transfer between channels due to stimulated Raman scattering effect is analyzed showing up to 2-dB power tilt at optimum power for the largest transmitted bandwidth of 7.3 THz.
Autors: Gabriel Saavedra;Mingming Tan;Daniel J. Elson;Lidia Galdino;Daniel Semrau;Md. A Iqbal;Ian D. Phillips;Paul Harper;Andrew Ellis;Benn C. Thomsen;Domaniç Lavery;Robert I. Killey;Polina Bayvel;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4809 - 4816
Publisher: IEEE
 
» Experimental and Analytical Study of Single-Phase Squirrel-Cage Induction Motor Considering End-Ring Porosity Rate
Abstract:
Single-phase squirrel-cage induction motors are widely used in household and industrial electronics, because of their simplicity, low cost, and ruggedness. The cage rotor of the induction motor is produced using laminated electrical steel sheets subjected to die-casting processes with various manufacturing parameters. However, the die-casting process generates pores in the cage-rotor end-ring. These pores have a significant effect on the motor properties, which cannot be accurately analyzed. In this paper, squirrel-cage rotors with different porosities were prepared by varying the die-casting process. Then, the end-ring porosity was accurately analyzed using X-ray computed tomography. The inter-bar resistance of the squirrel-cage rotor was calculated from the end-ring porosity rate. Finite-element analysis (FEA) was used to predict the effects of porosity on the motor performance. Finally, the motor was tested, and the measurements were compared with the FEA-predicted results. The analytical and experimental results obtained for a 1.5 kW single-phase squirrel-cage induction motor were very similar, when the end-ring porosity was included in the analysis.
Autors: Kyu-Seok Lee;Sung-Ho Lee;Jung-Hyung Park;Jeong-Man Kim;Jang-Young Choi;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Experimental and Numerical Study of the Behavior of a Multilayer for Active Magnetic Refrigerator Based on La-Fe-Co-Si
Abstract:
This paper is dedicated to study the experimental validation of a numerical model based on La-Fe-Co-Si layered operating near room temperature. For the purpose of this paper, a numerical simulation based on the transient energy equations is proposed for modeling the heat exchange between the multilayer material and the carrier fluid in the regenerator bed with an applied magnetic field of 1.5 T. The main findings of the simulation show a comparison between the numerical model and experimental setup including the magnetocaloric effect of La-Fe-Co-Si, pressure drop, and exergy and exergetic efficiency.
Autors: Younes Chiba;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Experimental Characterization of a Three-Rod Magnetostrictive Device for Energy Harvesting
Abstract:
Energy harvesting allows the conversion of environmental energy into electrical energy to feed low-power consumption electronics. In particular, this method can be exploited to supply wireless sensors nodes for structural health monitoring (SHM) when the electric network source is not present. Indeed, vibrations induced by vehicle traffic on a bridge could be converted into electrical energy, but suitable devices are needed. This paper presents experimental tests over a device based on three Galfenol rods, where electrical and magnetic parameters are changed and tested with different mechanical sources in order to seek the best performance.
Autors: Carmine Stefano Clemente;Daniele Davino;Ciro Visone;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Experimental Comparison of Probabilistic Shaping Methods for Unrepeated Fiber Transmission
Abstract:
This paper studies the impact of probabilistic shaping on effective signal-to-noise ratios (SNRs) and achievable information rates (AIRs) in a back-to-back configuration and in unrepeated nonlinear fiber transmissions. For the back-to-back setup, various shaped quadrature amplitude modulation (QAM) distributions are found to have the same implementation penalty as uniform input. By demonstrating in transmission experiments that shaped QAM input leads to lower effective SNR than uniform input at a fixed average launch power, we experimentally confirm that shaping enhances the fiber nonlinearities. However, shaping is ultimately found to increase the AIR, which is the most relevant figure of merit, as it is directly related to spectral efficiency. In a detailed study of these shaping gains for the nonlinear fiber channel, four strategies for optimizing QAM input distributions are evaluated and experimentally compared in wavelength division multiplexing (WDM) systems. The first shaping scheme generates a Maxwell–Boltzmann (MB) distribution based on a linear additive white Gaussian noise channel. The second strategy uses the Blahut–Arimoto algorithm to optimize an unconstrained QAM distribution for a split-step Fourier method based channel model. In the third and fourth approach, MB-shaped QAM and unconstrained QAM are optimized via the enhanced Gaussian noise (EGN) model. Although the absolute shaping gains are found to be relatively small, the relative improvements by EGN-optimized unconstrained distributions over linear AWGN optimized MB distributions are up to 59%. This general behavior is observed in 9-channel and fully loaded WDM experiments.
Autors: Julian Renner;Tobias Fehenberger;Metodi P. Yankov;Francesco Da Ros;Søren Forchhammer;Georg Böcherer;Norbert Hanik;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:22, pages: 4871 - 4879
Publisher: IEEE
 
» Experimental Evaluation of the Static Characteristics of Multi-Degree-of-Freedom Spherical Actuators
Abstract:
Multi-degree-of-freedom (multi-DOF) actuators have been developed to be applied in the fields of robotics and industrial machinery. In general, an actuating system with several-DOF is composed of single-DOF motors, which results in large, heavy, and complicated structures. Therefore, multi-DOF actuators are expected to solve these problems, and various actuators have been studied. Unlike single-DOF motors, the multi-DOF actuators can generate torque in various directions at different positions. Due to this, it is difficult to measure the static torque characteristics. In this paper, a measuring method of the torque constant is proposed in order to measure the static torque characteristics. This method can be used to evaluate the static torque characteristics over an entire movable range by measuring only a limited number of points. Finally, the effectiveness of this method is discussed.
Autors: Kazuaki Takahara;Katsuhiro Hirata;Noboru Niguchi;Yusuke Nishiura;Yo Sakaidani;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Experimental Study of Iron Losses Generated by a Uniform Rotating Field
Abstract:
This paper introduces a mock-up with a solid iron cylinder rotating in a fixed excitation frame powered by dc current. A uniform field is created in the rotating cylinder, which is driven by an external motor. The braking torque is measured, allowing the study of iron losses generated by a uniform rotating field. The aim is to advance toward a vector iron loss model that takes into account different magnetization directions and their interdependency. The eddy current losses are the dominant loss source in the mock-up, rendering it easier to model. A standard eddy currents model is proposed. It models well the losses at low and medium magnetic flux density, but lower losses are measured near saturation levels. This could be due to the high thickness to radius ratio changing the eddy current paths near the edges of the rotor, which can be later analyzed by a full 3-D finite-element method analysis. A 2-D finite-element method simulation is performed, which estimates the magnetic flux heterogeneity in the rotor. Several lessons are drawn from this mock-up, which prepares a second version with a higher speed and a longer laminated stack rotor. A higher air gap will decrease the voltage fluctuation in the primary winding, a smaller angular opening of the excitation frame will improve the uniformity of the flux in the rotor.
Autors: A. Bernot;A. Giraud;Y. Lefèvre;J.-F. Llibre;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Experimental Verification of Effects in an Emergency Stop by Installation of Magnetorheological Fluid Damper to an Elevator
Abstract:
In the countries sailing with an economic tailwind, many skyscrapers are going up. These buildings require systems of high-speed, safety, and comfortable elevators for its speedy vertical transportation. If the drives of elevator fail, an emergency stop device is supposed to work immediately for saving passengers lives in the elevator cage, because the elevator has outrageous potential energy to the ground level and kinetic energy. Its dangerousness is nothing compared to that in railways as surface transport. In order to reduce impact force to passengers in emergency stoppage, the authors had already proposed a safe and dependable magnetorheological fluid (MRF) semi-active damper (i.e., MRF damper) put between an emergency stop device and an elevator cage. In this paper, in order to evaluate the effects of the MRF damper, we would like to make up a test installation, which is composed of an MRF damper, a spring, an elevator cage, linear servo mechanics with a ball screw for generating the brake force of emergency stop device, sensors, and a digital controller with Labview. In addition, we would like to verify the validity of our system by many experiments.
Autors: Naoki Kobayashi;Keisuke Kawase;Shunsuke Sato;Toshiko Nakagawa;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Explicit Construction of AG Codes From a Curve in the Tower of Bassa-Beelen-Garcia-Stichtenoth
Abstract:
We present multi-point algebraic geometric codes overstepping the Gilbert-Varshamov bound. The construction is based on a curve in the tower introduced by Bassa et al. These codes are described in detail by constructing generator matrices. It turns out that these codes have nice properties similar to those of Hermitian codes. The duals are also such codes and can be expressed as an explicit formula.
Autors: Chuangqiang Hu;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7237 - 7246
Publisher: IEEE
 
» Exploit the Value of Production Data to Discover Opportunities for Saving Power Consumption of Production Tools
Abstract:
Semiconductor industry is both technology and energy intensive. There is a critical need to develop effective ways for energy saving to support smart and green production. This paper aims to develop data mining approach based on neural networks to exploit the value of production data and derive improvement directions for energy saving. In particular, the power consumption per wafer processed step (kilowatt hour per move, kwh/move) of individual production tool sets can be estimated, in which the relationships between kwh/move and 19 individual input factors, including “lot size,” “process time,” “uptime,” “usable machine,” “Q-time constrain,” and “sampling rate” are derived. An empirical study was conducted in a leading wafer fab and the results have shown practical viability of the proposed approach to discover effective opportunities for saving 17.21% power consumption by production tool sets.
Autors: Chih-Min Yu;Chen-Fu Chien;Chung-Jen Kuo;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 345 - 350
Publisher: IEEE
 
» Exploiting Experts’ Knowledge for Structure Learning of Bayesian Networks
Abstract:
Learning Bayesian network structures from data is known to be hard, mainly because the number of candidate graphs is super-exponential in the number of variables. Furthermore, using observational data alone, the true causal graph is not discernible from other graphs that model the same set of conditional independencies. In this paper, it is investigated whether Bayesian network structure learning can be improved by exploiting the opinions of multiple domain experts regarding cause-effect relationships. In practice, experts have different individual probabilities of correctly labeling the inclusion or exclusion of edges in the structure. The accuracy of each expert is modeled by three parameters. Two new scoring functions are introduced that score each candidate graph based on the data and experts’ opinions, taking into account their accuracy parameters. In the first scoring function, the experts’ accuracies are estimated using an expectation-maximization-based algorithm and the estimated accuracies are explicitly used in the scoring process. The second function marginalizes out the accuracy parameters to obtain more robust scores when it is not possible to obtain a good estimate of experts’ accuracies. The experimental results on simulated and real world datasets show that exploiting experts’ knowledge can improve the structure learning if we take the experts’ accuracies into account.
Autors: Hossein Amirkhani;Mohammad Rahmati;Peter J. F. Lucas;Arjen Hommersom;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Nov 2017, volume: 39, issue:11, pages: 2154 - 2170
Publisher: IEEE
 
» Exploiting the Maxwell-Wagner-Sillars Effect for Displacement-Current Phase Tomography of Two-Phase Flows
Abstract:
We introduce a method based on the Maxwell–Wagner–Sillars (MWS) effect to improve the performance of displacement-current phase tomography (DCPT) applied to two-phase flow imaging. DCPT utilizes as set of mutual admittance measurements between electrodes placed around a region of interest (RoI). This measurement can extract the phase of the displacement current between the electrodes so as to characterize the spatial distribution of the conductivity or dielectric loss inside the RoI. By exploiting the fact that the measured data at different frequencies will exhibit distinct MWS effects, the proposed approach can extract additional information from the measure data set and improve the resolution of DCPT for the imaging of two-phase flows. Numerical simulations along with experimental results illustrate the main findings of this paper.
Autors: Rafiul K. Rasel;Cagdas Gunes;Qussai M. Marashdeh;Fernando L. Teixeira;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7317 - 7324
Publisher: IEEE
 
» Exploring the Crystal Structure Space of CoFe2P by Using Adaptive Genetic Algorithm Methods
Abstract:
Advances in theoretical and computational condensed matter physics have opened the possibility to predict and design magnetic materials for specific technological applications. In this paper, we use the adaptive–genetic algorithm technique for exploring the low-energy crystal structure configurations of Co0.25Fe0.5P0.25, aiming to find new low-energy non-cubic phases with high saturation magnetization that might be interesting for high-performance permanent magnet development.
Autors: P. Nieves;S. Arapan;S. Cuesta-López;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Exposing Approximate Computing Optimizations at Different Levels: From Behavioral to Gate-Level
Abstract:
Many classes of applications exhibit significant tolerance to inaccuracies in their computations. Some examples include image processing, multimedia applications, and machine learning. These inaccuracies can be exploited to build circuits with smaller area, lower power, and higher performance. Most previous work restricts the approximate optimizations to a particular level of abstraction or step within the VLSI process. This paper shows that a combined multilevel approach is far more superior. Thus, this paper exploits different optimizations visible only at each particular level, leading to better results than single-level methods. Moreover, approximate computing is highly data-dependent. Therefore, in this paper, we study the stability of the approximate circuits when the circuit is optimized for a particular data distribution and the final workload differs from it. Previous work mainly considers a single input data distribution and that this distribution is equal to the final workload. Results show that our proposed method can find better and more optimal configurations compared with previous work and can achieve circuits, which are more robust in environments with dynamic workloads.
Autors: Siyuan Xu;Benjamin Carrion Schafer;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Nov 2017, volume: 25, issue:11, pages: 3077 - 3088
Publisher: IEEE
 
» Extended Analysis of the $Z^{2}$ -FET: Operation as Capacitorless eDRAM
Abstract:
The Z2-FET operation as capacitorless DRAM is analyzed using advanced 2-D TCAD simulations for IoT applications. The simulated architecture is built based on actual 28-nm fully depleted silicon-on-insulator devices. It is found that the triggering mechanism is dominated by the front-gate bias and the carrier’s diffusion length. As in other FB-DRAMs, the memory window is defined by the ON voltage shift with the stored body charge. However, the Z2-FET’s memory state is not exclusively defined by the inner charge but also by the reading conditions.
Autors: Carlos Navarro;Joris Lacord;Mukta Singh Parihar;Fikru Adamu-Lema;Meng Duan;Noel Rodriguez;Binjie Cheng;Hassan El Dirani;Jean-Charles Barbe;Pascal Fonteneau;Maryline Bawedin;Campbell Millar;Philippe Galy;Cyrille Le Royer;Siegfried Karg;Paul Wells;Yong
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4486 - 4491
Publisher: IEEE
 
» Extraction of Front- and Rear-Interface Recombination in Silicon Double-Heterojunction Solar Cells by Reverse Bias Transients
Abstract:
We present a method, based upon reverse-recovery (RR) transient measurements, for determining the interface recombination parameters of double-sided heterojunction solar cells. A physics-based model is developed, and normalized parameters are used to provide results that can be scaled to arbitrary wafer thickness and minority-carrier diffusion coefficient. In the case of dominant recombination at only one interface, interface recombination velocity can be extracted directly from RR times. In devices with significant recombination at both interfaces, numerical modeling must be used. The effects of minority-carrier current spreading in small devices can be corrected for analytically. The results are then applied to both PEDOT/ n-Si and PEDOT/n-Si/TiO2 heterojunction cells. We find that the PEDOT/n-Si interface, despite favorable band offsets and a significant built-in voltage, is not an ideal hole injector because of recombination at the PEDOT/n-Si interface. We also find that the effective surface recombination velocity at the Si-TiO2 interface in a metallized device is 330 cm/s, confirming that the interface has a low defect density. Finally, we reflect on the significance of these results for the further development of silicon heterojunction cells.
Autors: Alexander H. Berg;Ken A. Nagamatsu;James C. Sturm;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Nov 2017, volume: 64, issue:11, pages: 4518 - 4525
Publisher: IEEE
 
» Fabrication and Characterization of MWCNT-Based Bridge Devices
Abstract:
Carbon nanotubes (CNTs) are one of the most actively researched structural materials due to their interesting electrical, mechanical, and chemical properties. Unlike single walled carbon nanotubes (SWCNTs), little work has been focused on multi-walled carbon nanotubes (MWCNTs) and their potential for practical devices. Here, we have fabricated bridge-shape devices integrating MWCNTs (> 50 nm in outer diameter) using three processes: optical lithography, electron beam-induced platinum deposition, and surface micromachining. Each device consists of a doubly-clamped nanotube suspended over gold electrodes on a highly conductive Si substrate. The suspended nanotubes are characterized individually using Raman spectroscopy and semiconductor parameters analysis and, overall, show, high crystallinity and low electrical resistance. The spring constants of doubly-clamped nanotubes were characterized using atomic force microscopy force−displacement measurements, with values as high as 70 N/m observed. Highly stiff MWCNTs are promising for a variety of applications, such as resonators and electrical interconnects. Through simulations, we estimate the resonance frequencies and pull-in voltages of these suspended nano-structures. The dependence of key parameters, such as the nanotube's length, Young's modulus, axial stress, and wall thickness is also discussed.
Autors: Karumbaiah N. Chappanda;Nitin M. Batra;Jorge A. Holguin-Lerma;Pedro M. F. J. Costa;Mohammad I. Younis;
Appeared in: IEEE Transactions on Nanotechnology
Publication date: Nov 2017, volume: 16, issue:6, pages: 1037 - 1046
Publisher: IEEE
 
» Fabrication and Evaluation of PCB-Embedded Broadband Signal Transformers With Custom Machined Racetrack-Shaped Ferrite Cores for Ethernet Applications
Abstract:
To reduce the manufacturing variability in broadband ferrite-core magnetic components such as ethernet transformers, there is great industry interest in the embedding of the core materials within a planar substrate and fabricating the windings using high-precision photolithography. An embedding process has been previously developed and found to impose design restrictions on embedded devices that can be feasibly fabricated. It was previously found that a racetrack core shape (toroidal halves joined by straight legs) allows the most efficient use of area to embed multiple magnetic devices with maximum inductance. In this paper, three different sizes of racetrack-shaped cores were fabricated from bulk ferrite. The racetrack cores were then embedded within printed circuit board substrate, wound as transformers, and measured to evaluate bandwidth and inductance. It was found that the transformer mutual inductance was significantly reduced through the embedding process. However, the devices were found to exhibit excellent broadband coupling behavior. Certain designs of transformers met the inductance and bandwidth requirements of 100 and 1000Base-T ethernet.
Autors: David Bowen;Debtanu Basu;Charles Krafft;Isaak Mayergoyz;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Fabrication and Performance of Integrated Fluxgate for Current Sensing Applications
Abstract:
The recently developed Fluxgate technology from Texas Instruments has enabled the production of the industry’s first current sensing integrated circuit with a fully integrated fluxgate device and a compensation coil driver. This paper presents an overview of the Fluxgate technology, focusing on the fabrication and performance of the integrated magnetic field sensing device.
Autors: Dok Won Lee;Mona Eissa;Ann Gabrys;Byron Shulver;Erika Mazotti;Sudtida Lavangkul;Sopa Chevacharoenkul;Neal Murphy;Fuchao Wang;Yousong Zhang;Will French;Mark Jenson;Ricky Jackson;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Fabrication and Photovoltaic Properties of Dye-Sensitized Solar Cells Based on Graphene–TiO2 Composite Photoelectrode With ZnO Nanowires
Abstract:
In this paper, the photoelectrode of dye-sensitized solar cell (DSSC) was fabricated into a double-layer structure on the fluorine-doped tin oxide glass, which was synthesized by a graphene oxide–titanium dioxide composite layer (GO–TiO2), and a zinc oxide nanowires (ZNWs) layer. The morphology and effects of double layer were investigated by the field emission scanning electron microscopy, UV-visible spectrometer, and solar simulator. The enhancement of the photovoltaic performances of DSSC could be attributed to the high specific surface area of GO and high electron mobility of zinc oxide. Besides, the equivalent circuit and electrochemical properties of GO–TiO2/ZNWs double structure were also investigated by electrochemical impedance spectroscopy.
Autors: Jung-Chuan Chou;Pei-Hong You;Yi-Hung Liao;Chih-Hsien Lai;Chia-Ming Chu;Yu-Jen Lin;Wan-Yu Hsu;Chang-Chia Lu;Yu-Hsun Nien;
Appeared in: IEEE Transactions on Semiconductor Manufacturing
Publication date: Nov 2017, volume: 30, issue:4, pages: 531 - 538
Publisher: IEEE
 
» Fairness-Aware Spectral and Energy Efficiency in Spectrum-Sharing Wireless Networks
Abstract:
This paper introduces a fair and energy-efficient resource allocation framework in spectrum-sharing wireless networks with quality-of-service guarantees. Consider the tradeoff between energy efficiency and spectral efficiency, the multiobjective problem of spectral efficiency and energy efficiency is transformed into a problem that minimizes the total power consumption and maximizes the achievable utility, subject to power constraints and rate outage probability constraints. We then analyze the complexity of the considered problem; particularly, the optimization problem is NP-Hard when and and is convex for other values of the fairness index . After that, we adopt the successive convex approximation (SCA) approach to approximate and transform the NP-hard nonconvex optimization problem into a sequence of convex programs and propose two iterative SCA-based resource allocation algorithms. Extensive simulation results are presented to demonstrate the effectiveness and outperformance of the proposed algorithms over existing frameworks.
Autors: Quoc-Viet Pham;Won-Joo Hwang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Nov 2017, volume: 66, issue:11, pages: 10207 - 10219
Publisher: IEEE
 
» Fall Detection Utilizing Frequency Distribution Trajectory by Microwave Doppler Sensor
Abstract:
Falls are serious issues encountered in the lives of the elderly living alone. Since the elderly cannot stand up without support from a caregiver, or because they may lose consciousness after falling, they may remain on the floor for an extended period of time after a fall; this leads to serious complications including hypothermia, dehydration, and sometimes, even death. Therefore, immediate detection of falls is necessary. In this paper, we propose a fall detection system based on a microwave Doppler sensor. In the proposed system, we apply the frequency distribution trajectories corresponding to the velocities of the movements while falling, to a hidden Markov model. In order to evaluate the proposed system, we carry out verification experiments for three types of fall events (tripping, slipping, and fainting) and four types of non-fall events (walking, bending, sitting, and standing). From the results, the accuracy, positive predictive value, and negative predictive value are found to be 0.95, 0.94, and 0.97, respectively.
Autors: Kazuaki Shiba;Takashi Kaburagi;Yosuke Kurihara;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7561 - 7568
Publisher: IEEE
 
» Faraday Effect in Bi-Periodic Photonic-Magnonic Crystals
Abstract:
We present a theoretical investigation of the polarization plane rotation at light transmission—Faraday effect, through 1-D multilayered magneto-photonic systems consisting of periodically distributed magnetic and dielectric layers. We calculate Faraday rotation (FR) spectra of photonic-magnonic crystals, where cell (or supercell) is composed of magnetic layer and dielectric layer (or section of dielectric photonic crystal). We found that the FR of p-polarized incident light is increasing in the transmission band with the number of magnetic supercells. The increase of FR is observed also in vicinity of the band-gap modes localized in magnetic layers but the maximal polarization plane rotation angles are reached at minimal transmittivity. We show that presence of linear magneto-electric interaction in the magnetic layers leads to significant increase of the FR angles of s-polarized incident light in the vicinity of the fine-structured modes inside the photonic-band-gap.
Autors: Yuliya S. Dadoenkova;Nataliya N. Dadoenkova;Igor L. Lyubchanskii;Jarosław W. Kłos;Maciej Krawczyk;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 5
Publisher: IEEE
 
» Fast Algorithm and VLSI Architecture of Rate Distortion Optimization in H.265/HEVC
Abstract:
In H.265/high efficiency video coding (HEVC) encoding, rate distortion optimization (RDO) is an important cost function for mode decision and coding structure decision. Despite being near-optimum in terms of coding efficiency, RDO suffers from a high complexity. To address this problem, this paper presents a fast RDO algorithm and its very large scale implementation (VLSI) for both intra- and inter-frame coding. The proposed algorithm employs a quantization-free framework that significantly reduces the complexity for rate and distortion optimization. Meanwhile, it maintains a low degradation of coding efficiency by taking the syntax element organization and probability model of HEVC into consideration. The algorithm is also designed with hardware architecture in mind to support an efficient VLSI implementation. When implemented in the HEVC test model, the proposed algorithm achieves 62% RDO time reduction with 1.85% coding efficiency loss for the “all-intra” configuration. The hardware implementation achieves 1.6 × higher normalized throughput relative to previous works, and it can support a throughput of 8k@30fps (for four fine-processed modes per prediction unit) with 256 k logic gates when working at 200 MHz.
Autors: Heming Sun;Dajiang Zhou;Landan Hu;Shinji Kimura;Satoshi Goto;
Appeared in: IEEE Transactions on Multimedia
Publication date: Nov 2017, volume: 19, issue:11, pages: 2375 - 2390
Publisher: IEEE
 
» Fast and Fully Automatic Left Ventricular Segmentation and Tracking in Echocardiography Using Shape-Based B-Spline Explicit Active Surfaces
Abstract:
Cardiac volume/function assessment remains a critical step in daily cardiology, and 3-D ultrasound plays an increasingly important role. Fully automatic left ventricular segmentation is, however, a challenging task due to the artifacts and low contrast-to-noise ratio of ultrasound imaging. In this paper, a fast and fully automatic framework for the full-cycle endocardial left ventricle segmentation is proposed. This approach couples the advantages of the B-spline explicit active surfaces framework, a purely image information approach, to those of statistical shape models to give prior information about the expected shape for an accurate segmentation. The segmentation is propagated throughout the heart cycle using a localized anatomical affine optical flow. It is shown that this approach not only outperforms other state-of-the-art methods in terms of distance metrics with a mean average distances of 1.81±0.59 and 1.98±0.66 mm at end-diastole and end-systole, respectively, but is computationally efficient (in average 11 s per 4-D image) and fully automatic.
Autors: João Pedrosa;Sandro Queirós;Olivier Bernard;Jan Engvall;Thor Edvardsen;Eike Nagel;Jan D’hooge;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Nov 2017, volume: 36, issue:11, pages: 2287 - 2296
Publisher: IEEE
 
» Fast and Robust Self-Representation Method for Hyperspectral Band Selection
Abstract:
In this paper, a fast and robust self-representation (FRSR) method is proposed to select a proper band subset from hyperspectral imagery (HSI). The FRSR assumes the separability structure of the HSI band set and transforms the problem of separable nonnegative matrix factorization into the robust self-representation (RSR) model. Then, the FRSR incorporates structured random projections into the RSR model to improve computational efficiency. The solution of FRSR is formulated into optimizing a convex problem and the augmented Lagrangian multipliers are adopted to estimate the proper factorization localizing matrix in the FRSR. The selected band subset is constituted with the bands corresponding to the r largest diagonal entries of the factorization localizing matrix. The experimental results show that FRSR outperforms state-of-the-art techniques in classification accuracy with lower computational cost.
Autors: Weiwei Sun;Long Tian;Yan Xu;Dianfa Zhang;Qian Du;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Nov 2017, volume: 10, issue:11, pages: 5087 - 5098
Publisher: IEEE
 
» Fast Convergence Rates for Distributed Non-Bayesian Learning
Abstract:
We consider the problem of distributed learning, where a network of agents collectively aim to agree on a hypothesis that best explains a set of distributed observations of conditionally independent random processes. We propose a distributed algorithm and establish consistency, as well as a nonasymptotic, explicit, and geometric convergence rate for the concentration of the beliefs around the set of optimal hypotheses. Additionally, if the agents interact over static networks, we provide an improved learning protocol with better scalability with respect to the number of nodes in the network.
Autors: Angelia Nedić;Alex Olshevsky;César A. Uribe;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5538 - 5553
Publisher: IEEE
 
» Fast Intra Bunch Train Charge Feedback for FELs Based on Photo Injector Laser Pulse Modulation
Abstract:
Bunch charge variations in free electron lasers such as the free electron laser (FEL) in Hamburg (FLASH) or the European X-ray FEL (E-XFEL) impact the longitudinal phase space distribution of the electrons resulting in different bunch peak currents, bunch durations, and bunch shapes. The electron bunches are generated by short ultraviolet (UV) laser pulses impinging onto a photocathode inside a radio frequency (RF) accelerating cavity. At FLASH, bursts of bunches up to 800 pulses with an intra train repetition rate of 1 MHz are used and even higher repetition rates (up to 4.5 MHz) are planned at the E-XFEL. Charge variations along these bunch trains can be caused by variations of the laser pulse energies, instabilities of the accelerating fields in the RF cavity, and time-dependent effects in the photoemission process. To improve the intra bunch train charge flatness and to compensate train-to-train fluctuations, a dedicated digital control system, based on the Micro Telecommunication Computing Architecture (MicroTCA.4) standard, was designed, implemented, and successfully tested at FLASH. The system consists of a bunch charge detection module which analyzes data from a toroid system and provides the input signal for the controller which drives a fast UV Pockels cell installed in the optical path of the photocathode laser. The Pockels cell alters the laser polarization and thus the transmission through a polarizer. The modulation of UV laser pulse energy with an iterative learning feedforward minimizes the repetitive errors from bunch train to bunch train. A fast feedback algorithm implemented in a field-programmable gate array allows for fast tuning of bunch charge inside the bunch train. In this paper, a detailed description of the system and the first preliminary measurement results are presented.
Autors: Tomasz Kozak;Bernd Steffen;Sven Pfeiffer;Siegfried Schreiber;Andrzej Napieralski;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Nov 2017, volume: 64, issue:11, pages: 2904 - 2910
Publisher: IEEE
 
» Fast Optical Flow Estimation Without Parallel Architectures
Abstract:
According to recent results on Middlebury, MPI Sintel, and KITTI benchmarks, the accuracy of optical flow estimation algorithms has been significantly improved. The speed of them, however, has been too slow to meet the requirement of real-time applications. As a result, some parallel architectures (such as FPGA or GPU) have to be used for accelerating. Therefore, reducing the computational cost of optical flow estimation makes a lot of sense. To overcome the above issues, this paper proposes a fast local method based on 3D-gradients and approximate nearest-neighbor field (NNF), which is different from the widely used global model. In our method, NNF is used to provide initial optical flow field, and the proposed fast 3D-gradients-based local operator is used to propagate flow from coarse level to finer level in the coarse-to-fine refinement. We implement two versions of our method (with/without NNF initialization). Experimental results show that our method has a significant advantage for speed over other methods, where the fast version is capable of processing sequence () at frames/s without parallel architectures. Meanwhile, our accuracy is also within acceptable levels on both small and large motion for some real-time applications.
Autors: En Zhu;Yuanwei Li;Yanling Shi;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Nov 2017, volume: 27, issue:11, pages: 2322 - 2332
Publisher: IEEE
 
» Fast Software Implementations of Bilinear Pairings
Abstract:
Advancement in pairing-based protocols has had a major impact on the applicability of cryptography to the solution of more complex real-world problems. However, the computation of pairings in software still needs to be optimized for different platforms including emerging embedded systems and high-performance PCs. Few works in the literature have considered implementations of pairings on the former applications despite their growing importance in a post-PC world. In this paper, we investigate the efficient computation of the Optimal-Ate pairing over special class of pairing friendly Barreto-Naehrig curves in software at different security levels. We target both applications and perform our implementations on ARM-powered processors (with and without NEON instructions) and PC processors. We exploit state-of-the-art techniques and propose new optimizations to speed up the computation in the different levels including tower field and curve arithmetic. In particular, we extend the concept of lazy reduction to inversion in extension fields, analyze an efficient alternative for the sparse multiplication used inside the Miller’s algorithm and reduce further the cost of point/line evaluation formulas in affine and projective homogeneous coordinates. In addition, we study the efficiency of using M-type and D-type sextic twists in the pairing computation and carry out a detailed comparison between affine, Jacobian, and homogeneous coordinate systems. Our implementations on various mass-market emerging embedded devices significantly improve the state-of-the-art of pairing computation on ARM-powered devices and x86-64 PC platforms. For ARM implementations we achieved considerably faster computations in comparison to the counterparts.
Autors: Reza Azarderakhsh;Dieter Fishbein;Gurleen Grewal;Shi Hu;David Jao;Patrick Longa;Rajeev Verma;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Nov 2017, volume: 14, issue:6, pages: 605 - 619
Publisher: IEEE
 
» Fast Spectral Clustering With Anchor Graph for Large Hyperspectral Images
Abstract:
The large-scale hyperspectral image (HSI) clustering problem has attracted significant attention in the field of remote sensing. Most traditional graph-based clustering methods still face challenges in the successful application of the large-scale HSI clustering problem mainly due to their high computational complexity. In this letter, we propose a novel approach, called fast spectral clustering with anchor graph (FSCAG), to efficiently deal with the large-scale HSI clustering problem. Specifically, we consider the spectral and spatial properties of HSI in the anchor graph construction. The proposed FSCAG algorithm first constructs anchor graph and then performs spectral analysis on the graph. With this, the computational complexity can be reduced to , which is a significant improvement compared to conventional graph-based clustering methods that need at least , where , , and are the number of samples, features, and anchors, respectively. Several experiments are conducted to demonstrate the efficiency and effectiveness of the proposed FSCAG algorithm.
Autors: Rong Wang;Feiping Nie;Weizhong Yu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Nov 2017, volume: 14, issue:11, pages: 2003 - 2007
Publisher: IEEE
 
» Fast Successive-Cancellation Decoding of Polar Codes: Identification and Decoding of New Nodes
Abstract:
The decoding latency of polar codes can be reduced by implementing fast parallel decoders in the last stages of decoding. In this letter, we present five such decoders corresponding to different frozen-bit sequences to improve the decoding speed of polar codes. Implementing them achieves significant latency reduction without tangibly altering the bit-error-rate performance of the code.
Autors: Muhammad Hanif;Masoud Ardakani;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2360 - 2363
Publisher: IEEE
 
» Fast Uplink Synchronization in LTE-Like Systems
Abstract:
We show a way to accelerate the successive multiuser detection (SMUD) algorithm for initial uplink synchronization (IUS) in an LTE-like system. We develop a new data model to pose IUS as a signal representation problem in a Fourier basis. We provide the theoretical guidelines for generating codes using the data model. Our method significantly reduces the complexity of computationally demanding multiplication steps of the SMUD algorithm.
Autors: Md Mashud Hyder;Kaushik Mahata;
Appeared in: IEEE Communications Letters
Publication date: Nov 2017, volume: 21, issue:11, pages: 2424 - 2427
Publisher: IEEE
 
» Fast- and Low-Complexity atan2(a,b) Approximation [Tips and Tricks]
Abstract:
This article presents a new entry to the class of published algorithms for the fast computation of the arctangent of a complex number. Our method uses a look-up table (LUT) to reduce computational errors. We also show how to convert a large-sized LUT addressed by two variables to an equivalent-performance smaller-sized LUT addressed by only one variable. In addition, we demonstrate how and why the use of follow-on LUTs applied to other simple arctan algorithms produce unexpected and interesting results.
Autors: Vicente Torres;Javier Valls;Richard Lyons;
Appeared in: IEEE Signal Processing Magazine
Publication date: Nov 2017, volume: 34, issue:6, pages: 164 - 169
Publisher: IEEE
 
» Fatigue-Aware Management of Cellular Networks Infrastructure with Sleep Modes
Abstract:
We consider the problem of controlling the rate of failures triggered by fatigue processes of Base Stations (BSs) in cellular networks subject to Sleep Modes (SMs). Specifically, the increase of time spent in SM tends to decrease the BS failure rate by following, e.g., the Arrhenius law. However, the transitions between the power states tend to increase the BS failure rate, which can be predicted by the Coffin-Manson model. In this context, the energy savings triggered by SMs would not be economically useful if the BS failure rate were increased too much. Our goal is therefore to tackle the problem of minimizing the BS failure rate in a cellular network subject to SMs. After showing that the optimal formulation of the problem is NP-Hard, we propose a new algorithm, named LIFE, to practically solve it. We run LIFE on different scenarios (driven by LTE and legacy UMTS technologies). Our results show that LIFE outperforms two previous energy-aware algorithms, which instead do not take into account the BS failure rate. Specifically, our solution is able to achieve up to 40 percent of power saving at night, without a strong penalty in the BS failure rate.
Autors: Luca Chiaraviglio;Francesca Cuomo;Marco Listanti;Edoardo Manzia;Martina Santucci;
Appeared in: IEEE Transactions on Mobile Computing
Publication date: Nov 2017, volume: 16, issue:11, pages: 3028 - 3041
Publisher: IEEE
 
» Fault-Tolerant Capability of Deadbeat-Direct Torque and Flux Control for Three-Phase PMSM Drives
Abstract:
This paper investigates the performance of a three-phase permanent magnet synchronous motor (PMSM) drive operating under a single fault, adopting a low cost and fault-tolerant control based on deadbeat-direct torque and flux control (DB-DTFC). Under faulty operation, this fault-tolerant DB-DTFC offers an independent regulation of the electromagnetic torque and the stator flux linkage by using the same torque line equation, stator flux linkage, and current observers adopted during healthy conditions, requiring very limited hardware reconfigurations. In particular, it has been demonstrated that in a fault situation, the same drive model equations adopted for the healthy electric drive can be exploited with very limited detrimental effects on the drive performance simply by applying a suitable reference frame transformation set in the torque and flux control structure. The proposed fault-tolerant DB-DTFC has been validated by experimental tests, confirming that the proposed fault-tolerant DB-DTFC ensures satisfactory faulty operations and drive stability, without significant degradation of parameter sensitivity, keeping limited the increment of computational efforts.
Autors: Giuseppe Scarcella;Giacomo Scelba;Mario Pulvirenti;Robert D. Lorenz;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Nov 2017, volume: 53, issue:6, pages: 5496 - 5508
Publisher: IEEE
 
» FDA approves a prescription-only app for addiction [News]
Abstract:
Drug and alcohol users will soon be able to get a prescription for a mobile app that could help them stay clean. Developed by Pear Therapeutics in Boston and San Francisco, the app helps people recovering from addiction stay on track while participating in outpatient treatment. The U.S. Food and Drug Administration (FDA) approved the prescription-only software in September.
Autors: Emily Waltz;
Appeared in: IEEE Spectrum
Publication date: Nov 2017, volume: 54, issue:11, pages: 9 - 10
Publisher: IEEE
 
» Fe2O3–SiO2 Core–Shell Nanoparticles Conjugated With Bovine Serum Albumin
Abstract:
This paper presents a systematic study of bovine serum albumin (BSA) conjugation on the amine-functionalized magnetic nanoparticles (MNPs) and the effects of various experimental parameters on the conjugation process. The amine-functionalized Fe2O3 NPs with silica shell were synthesized through surface modification. The BSA conjugation on the amine-functionalized Fe2O3 NPs was achieved through covalent binding via carbodiimide activation. Morphology and magnetic properties of the nanoparticles were investigated. The influence of reaction time, the initial protein concentration, and the temperature on BSA conjugation was studied. The increased reaction time promoted the conjugation of BSA on the Fe2O3 NPs and finally reached the saturation at 43.4 mg/g. The initial BSA concentration can increase the amount of conjugated BSA. The temperature exhibited no significant effect on the conjugation process. The results are useful for designing effective fabrication strategy for protein-conjugated nanomaterials.
Autors: Yun Teng;Philip W. T. Pong;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 6
Publisher: IEEE
 
» Feasibility of Single-Beam Interference Alignment in Multi-Carrier Interference Channels
Abstract:
Sun and Luo recently showed that if the vector-space single-beam interference alignment problem for a -user, -carrier interference channel is feasible, then . We prove the converse, that if , then the problem is feasible, i.e., that the requisite beamformers do exist.
Autors: David Grant;Mahesh K. Varanasi;
Appeared in: IEEE Transactions on Information Theory
Publication date: Nov 2017, volume: 63, issue:11, pages: 7352 - 7357
Publisher: IEEE
 
» FeCoNi-Coated Glass Fabric/Polycarbonate Composite Sheets for Electromagnetic Absorption and Shielding
Abstract:
In order to evaluate the electromagnetic (EM) absorption and shielding effects in near-field and far-field regions, the FeCoNi-coated glass fabric/polycarbonate composite sheets were fabricated. The composite sheets were composed of the laminated structure, which has one or two ply-FeCoNi-coated glass fabrics with or without Ni grid in polymer matrix. The evaluation of EM absorption and shielding behaviors was measured by using a microstrip line and a shielded loop antenna, which is based on IEC62333 in near field and rectangular waveguide at the X-band region in the far-field region. The power absorptions were up to about 86% at 10 GHz. The inter-decoupling effect for FeCoNi-coated glass fabric with Ni grid in composite exhibited about 45 dB at around 1.3 GHz, which is comparable to that of a conductive Cu foil. The shielding effectiveness was obtained over 70 dB at the X-band region for FeCoNi-coated glass fabric with Ni grid composite sheets.
Autors: Joonsik Lee;Byung Mun Jung;Sang Bok Lee;Sang-Kwan Lee;Ki Hyeon Kim;
Appeared in: IEEE Transactions on Magnetics
Publication date: Nov 2017, volume: 53, issue:11, pages: 1 - 4
Publisher: IEEE
 
» Feedback Stability of Negative Imaginary Systems
Abstract:
This paper extends the robust feedback stability theorem of negative imaginary systems by removing restrictive assumptions on the instantaneous gains of the systems that were imposed in the earlier literature, and it further generalizes this robust analysis result into the case that allows negative imaginary systems to have poles at the origin. In doing so, we extend the class of negative imaginary systems for which this robust stability theorem is applicable. We also show that this new generalized necessary and sufficient result specializes to the earlier theorems under the same assumptions. We additionally prove that the previously known dc gain condition is not only necessary and sufficient for robust feedback stability under the earlier specified instantaneous gain assumptions, but is also necessary and sufficient for robust feedback stability under new, different and equally simple assumptions. The general robust feedback stability theorem for negative imaginary systems with free body dynamics (i.e., poles at the origin) derived in this paper also specializes to the case that is only applicable for the negative imaginary system without poles at the origin. Since the results for negative imaginary systems with free body dynamics developed in this paper depend on the existence of a matrix with certain properties, we also propose a systematic construction of this matrix and show that construction of one such is sufficient for determining the feedback stability of the closed-loop system. Finally, examples are used to demonstrate the applicability of the results.
Autors: Alexander Lanzon;Hsueh-Ju Chen;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Nov 2017, volume: 62, issue:11, pages: 5620 - 5633
Publisher: IEEE
 
» FEM-Simulation and Experimental Realization of Low-Cost Electrowetting Actuators for a Flexible Microfluidic Pixel
Abstract:
We investigate and characterize three different fabrication methods facilitating low-cost electrowetting-on-dielectric (EWOD) structures. EWOD allows setting fluid droplets in motion by electrically altering the surface tension equilibrium at the triple contact line. We present a fabrication method for flexible EWOD structures by screen printing a transparent and conducting poly (3, 4-ethylenedioxythiophene) polystyrene sulfonate (PDOT:PSS) polymer on polyethylene terephthalate (PET) foil. As a demonstrator for applications, i.e., a flexible microfluidic EWOD display cell is simulated using FEM and characterized in terms of feasibility and response speed for various pixel scaling. The accordingly fabricated microfluidic pixel serves as a basis cell for a bendable and flexible EWOD cell multigrid, where all pixels are directly addressable.
Autors: Andreas Tröls;Herbert Enser;Bernhard Jakoby;
Appeared in: IEEE Sensors Journal
Publication date: Nov 2017, volume: 17, issue:22, pages: 7273 - 7280
Publisher: IEEE
 
» Femtosecond Laser Inscription of Fiber Bragg Grating in Twin-Core Few-Mode Fiber for Directional Bend Sensing
Abstract:
We demonstrated femtosecond laser inscription of fiber Bragg gratings (FBGs) in a twin-core few-mode fiber (TC-FMF) for directional bend sensing. An FBG was selectively inscribed in one core of the TC-FMF by using an 800 nm femtosecond laser through a phase mask. Three resonance peaks at the wavelengths of 1549.05, 1547.65, and 1546.08 nm were observed in the reflection spectrum of the TC-FM FBG, and were generated by the LP01 mode resonance, LP01-LP11 mode cross-coupling resonance, and LP11 mode resonance, respectively. Moreover, the TC-FM FBG exhibited the capability of directional bend sensing and achieved a maximum bend sensitivity of -37.41 pm/m-1. Hence, the proposed TC-FM FBG directional bend sensors could further be developed as promising solutions for detecting vectorial seismic or acoustic waves and 3-D shape sensing.
Autors: Kaiming Yang;Jun He;Changrui Liao;Ying Wang;Shen Liu;Kuikui Guo;Jiangtao Zhou;Zhengyong Li;Zhan Tan;Yiping Wang;
Appeared in: Journal of Lightwave Technology
Publication date: Nov 2017, volume: 35, issue:21, pages: 4670 - 4676
Publisher: IEEE
 

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