Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 15

» Non-Orthogonal Multiple Access in Multi-Cell Networks: Theory, Performance, and Practical Challenges
Abstract:
Non-orthogonal multiple access (NOMA) is a potential enabler for the development of 5G and beyond wireless networks. By allowing multiple users to share the same time and frequency, NOMA can scale up the number of served users, increase spectral efficiency, and improve user-fairness compared to existing orthogonal multiple access (OMA) techniques. While single-cell NOMA has drawn significant attention recently, much less attention has been given to multi-cell NOMA. This article discusses the opportunities and challenges of NOMA in a multi-cell environment. As the density of base stations and devices increases, inter-cell interference becomes a major obstacle in multi-cell networks. As such, identifying techniques that combine interference management approaches with NOMA is of great significance. After discussing the theory behind NOMA, this article provides an overview of the current literature and discusses key implementation and research challenges, with an emphasis on multi-cell NOMA.
Autors: Wonjae Shin;Mojtaba Vaezi;Byungju Lee;David J. Love;Jungwoo Lee;H. Vincent Poor;
Appeared in: IEEE Communications Magazine
Publication date: Oct 2017, volume: 55, issue:10, pages: 176 - 183
Publisher: IEEE
 
» Non-Parametric Approach of Video Capsule Endoscope Localization Using Suboptimal Method of Position Bounded CWCL
Abstract:
For proper diagnosis, location of the wireless video capsule endoscope is required to be known by the physicians. In this paper, we propose an algorithm of localizing the capsule using path loss-based calibrated weighted centroid localization (CWCL). The main challenge in path loss-based localization is the highly randomness of measured path loss due to shadow fading and multi-path propagation effects of human body channel. To address the randomness in the measured path loss, we propose two methods of path loss estimation using Gaussian weighted average filter and the multiple input multiple output diversity scheme. Then, we calculate the weight of the sensor receiver position using the estimated path loss. Finally, the position of the capsule is estimated using position-bounded CWCL. We propose a realistic suboptimal method of estimating the calibration coefficient and also compute the optimal value of coefficient to set the benchmark. Additionally, we propose two boundary conditions on the estimated positions to improve the localization accuracy. We simulate our proposed algorithms using MATLAB to validate the accuracy and observe significant improvements without any prior knowledge of channel parameters. The proposed algorithms improve the accuracy up to 5.14-mm root mean square error and outperform the existing literature.
Autors: Umma Hany;Lutfa Akter;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6806 - 6815
Publisher: IEEE
 
» Non-Stationary Rician Noise Estimation in Parallel MRI Using a Single Image: A Variance-Stabilizing Approach
Abstract:
Parallel magnetic resonance imaging (pMRI) techniques have gained a great importance both in research and clinical communities recently since they considerably accelerate the image acquisition process. However, the image reconstruction algorithms needed to correct the subsampling artifacts affect the nature of noise, i.e., it becomes non-stationary. Some methods have been proposed in the literature dealing with the non-stationary noise in pMRI. However, their performance depends on information not usually available such as multiple acquisitions, receiver noise matrices, sensitivity coil profiles, reconstruction coefficients, or even biophysical models of the data. Besides, some methods show an undesirable granular pattern on the estimates as a side effect of local estimation. Finally, some methods make strong assumptions that just hold in the case of high signal-to-noise ratio (SNR), which limits their usability in real scenarios. We propose a new automatic noise estimation technique for non-stationary Rician noise that overcomes the aforementioned drawbacks. Its effectiveness is due to the derivation of a variance-stabilizing transformation designed to deal with any SNR. The method was compared to the main state-of-the-art methods in synthetic and real scenarios. Numerical results confirm the robustness of the method and its better performance for the whole range of SNRs.
Autors: Tomasz Pieciak;Santiago Aja-Fernández;Gonzalo Vegas-Sánchez-Ferrero;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 2015 - 2029
Publisher: IEEE
 
» Noncoherent Alamouti Phase-Shift Keying With Full-Rate Encoding and Polynomial-Complexity Maximum-Likelihood Decoding
Abstract:
We consider Alamouti encoding that draws symbols from phase-shift keying and develop a new differential modulation scheme that attains full rate for any constellation order. In contrast to past work, the proposed scheme guarantees that the encoded matrix maintains the characteristics of the initial codebook and, at the same time, attains full rate so that all possible sequences of space-time matrices become valid. Surprisingly, although the validity of all sequences could be thought as a drawback with respect to the cost of noncoherent sequence decoding, in fact it turns out to be an advantage. Based on recent results in the context of quadratic-form maximization over finite alphabets, we exploit the full-rate property of the proposed scheme to develop a polynomial-complexity maximum-likelihood noncoherent sequence decoder whose order is solely determined by the number of receive antennas. Numerical studies show the superiority of the proposed scheme in comparison with contemporary alternatives in terms of encoding rate, decoding complexity, bandwidth efficiency, and throughput.
Autors: Panos P. Markopoulos;George N. Karystinos;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6688 - 6697
Publisher: IEEE
 
» Noncoherent Radar Detection in Correlated Pareto Distributed Clutter
Abstract:
Radar detection in the presence of spatially correlated Pareto distributed clutter is examined. It is shown how an order-statistic-based sliding window detection process must have its threshold set in order to achieve a constant false alarm rate. A particular multivariate Pareto distribution is constructed, based upon a compound Gaussian model with inverse gamma texture, whose pairwise marginal distributions have a general correlation. A specific example is then used for performance analysis.
Autors: Graham Victor Weinberg;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2628 - 2636
Publisher: IEEE
 
» Noncontact 3-D Speckle Contrast Diffuse Correlation Tomography of Tissue Blood Flow Distribution
Abstract:
Recent advancements in near-infrared diffuse correlation techniques and instrumentation have opened the path for versatile deep tissue microvasculature blood flow imaging systems. Despite this progress there remains a need for a completely noncontact, noninvasive device with high translatability from small/testing (animal) to large/target (human) subjects with trivial application on both. Accordingly, we discuss our newly developed setup which meets this demand, termed noncontact speckle contrast diffuse correlation tomography (nc_scDCT). The nc_scDCT provides fast, continuous, portable, noninvasive, and inexpensive acquisition of 3-D tomographic deep (up to 10 mm) tissue blood flow distributions with straightforward design and customization. The features presented include a finite-element-method implementation for incorporating complex tissue boundaries, fully noncontact hardware for avoiding tissue compression and interactions, rapid data collection with a diffuse speckle contrast method, reflectance-based design promoting experimental translation, extensibility to related techniques, and robust adjustable source and detector patterns and density for high resolution measurement with flexible regions of interest enabling unique application-specific setups. Validation is shown in the detection and characterization of both high and low contrasts in flow relative to the background using tissue phantoms with a pump-connected tube (high) and phantom spheres (low). Furthermore, in vivo validation of extracting spatiotemporal 3-D blood flow distributions and hyperemic response during forearm cuff occlusion is demonstrated. Finally, the success of instrument feasibility in clinical use is examined through the intraoperative imaging of mastectomy skin flap.
Autors: Chong Huang;Daniel Irwin;Mingjun Zhao;Yu Shang;Nneamaka Agochukwu;Lesley Wong;Guoqiang Yu;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2068 - 2076
Publisher: IEEE
 
» Nonconvex Penalty Based Low-Rank Representation and Sparse Regression for eQTL Mapping
Abstract:
This paper addresses the problem of accounting for confounding factors and expression quantitative trait loci (eQTL) mapping in the study of SNP-gene associations. The existing convex penalty based algorithm has limited capacity to keep main information of matrix in the process of reducing matrix rank. We present an algorithm, which use nonconvex penalty based low-rank representation to account for confounding factors and make use of sparse regression for eQTL mapping (NCLRS). The efficiency of the presented algorithm is evaluated by comparing the results of 18 synthetic datasets given by NCLRS and presented algorithm, respectively. The experimental results or biological dataset show that our approach is an effective tool to account for non-genetic effects than currently existing methods.
Autors: Lin Yuan;Lin Zhu;Wei-Li Guo;Xiaobo Zhou;Youhua Zhang;Zhenhua Huang;De-Shuang Huang;
Appeared in: IEEE/ACM Transactions on Computational Biology and Bioinformatics
Publication date: Oct 2017, volume: 14, issue:5, pages: 1154 - 1164
Publisher: IEEE
 
» Noncooperative Spectrum Sensing with Historical Sensing Data Mining in Cognitive Radio
Abstract:
In cognitive radio (CR), spectrum sensing is a critical task to effectively detect the spectrum holes. Through dynamically accessing such idle spectrum, CR can improve spectrum utilization and provide broad wireless band for wireless services. There are two types of spectrum sensing algorithms for CR, which are cooperative and noncooperative spectrum sensing. Noncooperative spectrum sensing is easier to implement, has less power costs, and is more robust to node failure, compared with cooperative spectrum sensing. In this paper, a novel noncooperative spectrum sensing algorithm has been proposed to exploit historical sensing data and boost the spectrum sensing performance. The hierarchical Dirichlet process is used to cluster the historical sensing data into groups, where each group shares a consensus spectrum state. Through exploiting the statistical correlations among historical sensing data, the uncertainty in spectrum sensing can be significantly minimized. The simulation results show that the proposed algorithm is better than the other three typical algorithms and has more than 10% detection performance improvement at false alarm probability 0.2 when received signal-to-noise ratio (SNR) is 5 dB.
Autors: Xin-Lin Huang;Yuan Xu;Jun Wu;Wei Zhang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 8863 - 8871
Publisher: IEEE
 
» Noncoplanar Geometry for Mobile NLOS MIMO Ultraviolet Communication With Linear Complexity Signal Detection
Abstract:
In this paper, we take a first step toward the mobile support for nonline-of-sight ultraviolet (UV) links by introducing a mesh UV network framework. Spatial multiplexing noncoplanar multiple-input-multiple-output (MIMO) UV system architecture is designed geometrically for the mobile mesh network to overcome the data rate bottleneck induced by scattered UV channel. Based on the MIMO UV channel characteristics, we further propose a modified sphere decoding (SD) method to accomplish MIMO signal detection in practical spatial correlated channels at a linear computational complexity. We evaluate mobile MIMO channel responses under various geometric parameters and the feasibility of this system geometry in and cases. Comparison of the bit error rates (BERs) between the modified SD, zero forcing, and SD is also done. Numerical results demonstrate that compared with the traditional linear array system structure, fully multiplexing is much easier via the noncoplanar MIMO geometry under very realistic parameters and the modified SD significantly improves the MIMO signal detection complexity with bit BER performance loss.
Autors: Heng Qin;Yong Zuo;Feiyu Li;Risheng Cong;Lingchao Meng;Jian Wu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 12
Publisher: IEEE
 
» Nondestructive Testing for Multi-Layer Metal-Metal Bonded Structure by Using Inductive Lock-In Thermograhy
Abstract:
Multilayer materials with metal-metal bonded structure have been widely applied in aviation, aerospace and nuclear industrial fields. The presence of inner defects such as debonding, air gaps leads to significant degradation of the load capacity and mechanical behaviors. Due to their complex structure, debonding detection in metal-metal structure inherently remains challenge. This paper proposes a feasibility study of non-destructive inspection of debonding defect in lead-steel sample by using inductive lock-in thermography (ILT). The detectability validation is carried out based on experimental studies. Theoretical analysis, excitation source and system design as well as various influence parameters of ILT are discussed and optimized. Fourier-transform based post-processing has been investigated to analyze both magnitude and phase images for defects identification. The obtained results have been promising validated and it indicated the ability to improve the signal-to-noise ratio. The comparative experiment using different methods (ILT, ECPT, and OLT) has been carried out. The results have revealed that the ILT has advantages and could be served as a strong candidate for practical adoption in debonding defect inspection in metal-metal bonded sample.
Autors: Yuyu Zhu;Bin Gao;Gui Yun Tian;Wai Lok Woo;Guangping Tang;Chaoming Sun;Jianwen Li;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6716 - 6723
Publisher: IEEE
 
» Nonlinear Analysis of Microwave Limiter Using Field-Circuit Coupling Algorithm Based on Time-Domain Volume-Surface Integral Method
Abstract:
This letter presents the nonlinear analysis of the physical characteristic of a microwave positive intrinsic-negative diode limiter using the field-circuit coupling algorithm based on a time-domain volume-surface integral equation method. In order to accelerate the Newton iteration solution of the nonlinear field-circuit coupling equations, an improved solution scheme of a matrix equation is used here. Moreover, the basic diode charge-control model employed contains both a forward and reverse process as well as emitter recombination. Experimental and numerical results are given to demonstrate the accuracy and the efficiency of the proposed method for the nonlinear analysis of commercial limiter.
Autors: Shitao Chen;Dazhi Ding;Zhenhong Fan;Rushan Chen;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Oct 2017, volume: 27, issue:10, pages: 864 - 866
Publisher: IEEE
 
» Nonlinear Compensation of Multi-CAP VLC System Employing Clustering Algorithm Based Perception Decision
Abstract:
Nonlinearities induced by the electrical amplifiers and the optoelectronic devices can be detrimental effects in visible light communication (VLC) systems. In this paper, clustering algorithm based perception decision (CAPD) is proposed to mitigate the nonlinear distortion in a VLC system. Aided by CAPD nonlinear compensation, we experimentally demonstrate a multiband CAP modulated VLC system consisting of a red light-emitting diode as a transmitter and a p-i-n photodiode based differential receiver. The system performances including the Q factor, bit error rate (BER), and computational complexity are thoroughly investigated when using a pure linear blind equalization scheme (modified cascaded multimodulus algorithm, M-CMMA) and when using hybrid linear and nonlinear equalizers (M-CMMA + Volterra series based nonlinear equalizer). The experiment results show that compared to pure linear equalizer case, the measured BER can be enhanced up to 1e−6, correspondingly the Q factor of each subband can be improved for around 1.6–2.5 dB by employing CAPD. The CAPD method can outperform the Volterra series based nonlinear equalizer with a lower BER value (at least 10% reduction) and relatively lower complexity. To the best of our knowledge, this is the first time that the clustering algorithm in machine learning is successfully applied to VLC systems.
Autors: Xingyu Lu;Kaihui Wang;Liang Qiao;Wen Zhou;Yiguang Wang;Nan Chi;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 9
Publisher: IEEE
 
» Nonlinear Look-Up Table Predistortion and Chromatic Dispersion Precompensation for IM/DD PAM-4 Transmission
Abstract:
In this paper, we propose and experimentally demonstrate 10 GBaud intensity modulation direct detection pulse amplitude modulation 4 transmission over 48-km single mode fiber (SMF). Look-up table predistortion and chromatic dispersion precompensation are employed to mitigate channel bandwidth constraint and nonlinear impairment. At the receiver side, decision-directed least mean square and cascaded multimodule algorithm are employed to improve the decision precision. By combining these techniques, link budgets of 5.3 and 4 dB are achieved at bit error rate of 1 × 10−3 for the back-to-back case and after transmission over 48-km SMF, respectively.
Autors: Pengqi Gou;Li Zhao;Kaihui Wang;Wen Zhou;Jianjun Yu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 7
Publisher: IEEE
 
» Nonlinear MIMO Transceivers Improve Wireless-Powered and Self-Interference-Aided Relaying
Abstract:
This paper investigates the design of robust nonlinear transceivers conceived for multiple-input multiple-output full-duplex wireless-powered relay networks in the face of realistic imperfect channel state information (CSI). A novel self-energy recycling aided relaying protocol is employed, whereby the relay node benefits from energy harvesting (EH) gleaned from the self-interfering link in addition to its primary energy. The proposed nonlinear transceiver relies on a Tomlinson-Harashima (TH) precoder along with an amplify-and-forward (AF) relaying matrix and a linear receiver, where the TH precoder is composed of a feedback matrix and a source precoding matrix. Two different criteria are considered for the robust design of the nonlinear transceiver in the presence of channel estimation errors modeled by the Gaussian distribution. The first one aims to minimize the mean-squared-error (MSE) at the destination subject to a transmit power constraint at the source and an EH constraint at the relay. The resultant optimization problem is converted to four subproblems and solved via an alternating optimization (AO) algorithm that iteratively updates the transceiver coefficients by sequentially addressing each subproblem, while keeping the other matrix variables fixed. The second design criterion aims to minimize the transmit power at the source under both MSE and EH constraints. Similarly, an AO-based iterative algorithm is proposed for solving this problem. Our simulation results show that the robust design advocated is capable of alleviating the effects of CSI errors, hence improving the robustness of the system over that of the corresponding linear designs.
Autors: Lei Zhang;Yunlong Cai;Minjian Zhao;Benoit Champagne;Lajos Hanzo;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6953 - 6966
Publisher: IEEE
 
» Nonsequential Speckle Reduction Method by Generating Uncorrelated Laser Subbeams With Equivalent Intensity Using a Reflective Spatial Light Modulator
Abstract:
Sequential speckle reduction methods demand the usage of fast modulators due to the short integration period of human eyes. Here, a nonsequential speckle reduction method by splitting one laser beam with short coherence length into uncorrelated laser subbeams (LSBs) is reported. In order to realize the most efficient speckle reduction, with the help of a polarization beam splitter, we have programmed a reflective spatial light modulator to make the LSBs intensities equivalent. Three uncorrelated LSBs with equivalent light intensity are designed to demonstrate this idea; the speckle contrast ratio is reduced to 0.55, which closes to the expected value of 0.58. This nonsequential speckle reduction method has no requirement of the modulators speed; thus, it has obvious merit comparing with the sequential speckle reduction methods.
Autors: Zhaomin Tong;Shaohua Song;Suotang Jia;Xuyuan Chen;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» NoSE: Schema Design for NoSQL Applications
Abstract:
Database design is critical for high performance in relational databases and a myriad of tools exist to aid application designers in selecting an appropriate schema. While the problem of schema optimization is also highly relevant for NoSQL databases, existing tools for relational databases are inadequate in that setting. Application designers wishing to use a NoSQL database instead rely on rules of thumb to select an appropriate schema. We present a system for recommending database schemas for NoSQL applications. Our cost-based approach uses a novel binary integer programming formulation to guide the mapping from the application's conceptual data model to a database schema. We implemented a prototype of this approach for the Cassandra extensible record store. Our prototype, the NoSQL Schema Evaluator (NoSE) is able to capture rules of thumb used by expert designers without explicitly encoding the rules. Automating the design process allows NoSE to produce efficient schemas and to examine more alternatives than would be possible with a manual rule-based approach.
Autors: Michael Joseph Mior;Kenneth Salem;Ashraf Aboulnaga;Rui Liu;
Appeared in: IEEE Transactions on Knowledge and Data Engineering
Publication date: Oct 2017, volume: 29, issue:10, pages: 2275 - 2289
Publisher: IEEE
 
» Notes on Stability of Time-Delay Systems: Bounding Inequalities and Augmented Lyapunov-Krasovskii Functionals
Abstract:
The bounding inequalities and the Lyapunov-Krasovskii functionals (LKFs) are important for the stability analysis of time-delay systems. Much attention has been paid to develop tighter inequalities for improving stability criteria, while the contribution of the LKFs has not been considered when discussing the relationship between the tightness of inequalities and the conservatism of criteria. This note is concerned with this issue. Firstly, it is proved that, when a simple LKF is applied, the stability criteria obtained by the Wirtinger-based inequality and the Jensen inequality are equivalent although the Wirtinger-based inequality is tighter. It means that the tighter inequality does not always lead to a less conservative criterion. Secondly, it is found that a suitable augmented LKF with necessary integral vectors in its derivative is required to achieve the advantage of the Wirtinger-based inequality. Based on this observation, two delay-product-type terms are introduced into the LKF to establish new stability criteria. Finally, a numerical example is given to verify the equivalence statements and to show the benefit of the proposed criteria.
Autors: Chuan-Ke Zhang;Yong He;Lin Jiang;Min Wu;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5331 - 5336
Publisher: IEEE
 
» Novel In Situ Boundary Detection Algorithm for Horizon Control in Longwall Mining
Abstract:
Real-time horizon control of the cutting head is very important in longwall mining for maximizing production, minimizing wear, and reducing postimpurity processing cost. If the horizon control sensor has to be mounted directly onto the cutting drum, then it needs to withstand the impacts from mining debris as well as shock and vibration at an average level of 26 Gs and a peak level of 100-G force. A single-frequency boundary detection sensor has been developed for this purpose for its simple design and extremely high measurement rate compared to other more sophisticated pulsed or swept-frequency radar sensors, and thus is more suitable for fast rotating cutting drums. However, the accuracy and effectiveness of this method in practice are severely limited by: 1) the interference of the much stronger reflection arising from the air–ground interface and 2) the uncertainty of the permittivity and conductivity of the ground. These two issues are alleviated by the proposed practical in situ calibration procedure discussed in this letter. This procedure only requires more than four calibration control cuts prior to the normal longwall mining cuts. The effectiveness of this method is demonstrated in this letter via both simulated and experimental data.
Autors: Jiu-Kun Che;Chi-Chih Chen;Larry G. Stolarczyk;Joseph T. Duncan;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1875 - 1879
Publisher: IEEE
 
» Novel Compact and Low-Cost Ultraweak Fabry–Perot Interferometer as a Highly Sensitive Refractive Index Sensor
Abstract:
A novel compact refractive index (RI) sensor based on an ultra-weak intrinsic fiber Fabry-Perot interferometer (FPI) is proposed and demonstrated, which is simply fabricated by splicing a tiny section of thin-core fiber to a single-mode fiber. Such an FPI exhibits an average RI sensitivity of 240dB/RIU over a wide RI range of 1.3326–1.4305, with a maximum sensitivity of 1110.7dB/RIU at the RI of 1.4305. In addition, the FPI can also achieve the simultaneous measurement of the RI and temperature.
Autors: Pengcheng Chen;Xuewen Shu;Haoran Cao;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Novel Decoupling Concept for Strongly Coupled Frequency-Dependent Antenna Arrays
Abstract:
This paper presents a novel wideband decoupling network for strongly frequency-dependent antenna couplings. The network consists of directional couplers, a transmission line, and a parallel resonant circuit. It cancels mutual coupling by the superposition of a designed coupling with the same magnitude as the original coupling but the opposite phase. Further, the proposed approach accommodates variations in the coupling magnitude and large group delays in the coupling phase. Therefore, it is easy to apply the approach to wideband applications. The design formulas are also derived. With these formulas, the computational results show that the resultant coupling with the proposed technique is 26.4 dB smaller than that of the original coupling at 12.2% bandwidth with a large group delay. Moreover, this paper also describes a technique for practical implementation using short stubs. The resultant coupling with the fabricated multiantenna is 12.6 dB smaller than the original, over the entire 12.2% frequency range. The degradation of radiation efficiency by the proposed circuit is sufficiently small and the enhancement of signal-to-noise ratio is demonstrated.
Autors: Hidetoshi Makimura;Kengo Nishimoto;Takashi Yanagi;Toru Fukasawa;Hiroaki Miyashita;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5147 - 5154
Publisher: IEEE
 
» Novel Design of Ultrabroadband Radar Cross Section Reduction Surfaces Using Artificial Magnetic Conductors
Abstract:
A novel technique for designing ultrabroadband radar cross section (RCS) reduction surfaces using artificial magnetic conductors (AMCs) is proposed in this paper. This technique overcomes the fundamental limitation of the conventional checkerboard design where the reflection phase difference of (180±37)° is required to achieve 10-dB RCS reduction. Initially, a planar surface for broadband RCS reduction is designed with two properly selected AMCs in a blended checkerboard architecture. A 10-dB RCS reduction is observed for more than 83% of the bandwidth (3.9–9.45 GHz) with this blended checkerboard design. After modifying the blended checkerboard design using the proposed novel technique, the 10-dB RCS reduction bandwidth increased to 91% fractional bandwidth (3.75–10 GHz) as the criteria of (180 ± 37)° reflection phase difference is no longer required. Measured data show an excellent agreement between the predicted, simulated, and measured data. Bistatic performance of the surface at various frequencies is also presented. Key steps for designing ultrabroadband RCS reduction checkerboard surface are summarized.
Autors: Anuj Y. Modi;Constantine A. Balanis;Craig R. Birtcher;Hussein N. Shaman;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5406 - 5417
Publisher: IEEE
 
» Novel Electrically Tunable Microwave Solenoid Inductor and Compact Phase Shifter Utilizing Permaloy and PZT Thin Films
Abstract:
A Permalloy (Py) thin film enabled tunable 3-D solenoid inductor is designed and fabricated. The special configuration of magnetic core is discussed and by selectively patterning Py thin film, the proposed tunable inductor can work at frequency up to several GHz range. The inductance of the solenoid inductor can be electrically tuned by dc current and the tunability is above 10%. Utilizing the implemented Py enabled tunable solenoid inductor and Lead Zirconate Titanate thin film enabled metal-insulator-metal capacitor, a compact fully electrically tunable lumped elements phase shifter is achieved. The tunable phase shifter has both inductive and capacitive tunability and the dual tunability significantly improves the tuning range and design flexibility. Moreover, the dual tunability is able to retain the equivalent characteristic impedance of the device in the process of the phase being tuned. The phase of the device can be tuned by fully electrical methods and when dc current and dc voltage are provided, the length normalized phase tunability is up to 210°/cm.
Autors: Tengxing Wang;Wei Jiang;Ralu Divan;Daniel Rosenmann;Leonidas E. Ocola;Yujia Peng;Guoan Wang;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Oct 2017, volume: 65, issue:10, pages: 3569 - 3577
Publisher: IEEE
 
» Novel Electromagnetic-Interference-Free Indoor Environment Monitoring System by Mobile Camera-Image-Sensor-Based VLC
Abstract:
Long-term exposure to radio frequency waves can have adverse effects on human health. It may cause bad effects especially to elderly people, children, and patients with weak immune systems. On the other hand, visible light communication technologies that use a light-emitting diode (LED) light source and a photodetector to transmit and receive data through visible light have a severe demerit that the modulation and demodulation processes in the system can be complicated. This paper presents a low-cost wireless mobile indoor environment monitoring system with no additional complicated signal detecting device, except a mobile device and sensor modules. Temperature, humidity, and CO concentration equivalent data are collected by sensor modules, and these data are modulated using frequency shift keying modulation. The modulated data are transmitted wirelessly by using a red–green–blue LED for transmitting multiple data concurrently. An Android application is developed to act as a light-signal receiver from multiple sensor modules. The image stream of the LED is captured and is processed locally in a mobile device. A single-receiver module with a camera image sensor can accept sensing data from six sensor modules simultaneously with a maximum transmission range up to 12 m and low error rate.
Autors: ZhenYang Ong;Vega Pradana Rachim;Wan-Young Chung;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 11
Publisher: IEEE
 
» Novel Integrated Helical Design of Single Optic Fiber for Shape Sensing of Flexible Robot
Abstract:
With the evolution of technology, it is now possible to build more flexible surgical instruments with multiple degrees of freedom that can be deployed in natural orifice translumenal endoscopic surgery, further reducing tissue damage, blood loss, and recovery time. However, the limits of flexible robots are mainly represented by the lack of accurate position feedback during the surgical procedure. The most critical problems of shape sensors are size and quantity limits, as well as sterilizability. This paper presents a novel helical configuration of single optic fiber with multiple fiber Bragg grating sensors to measure the shape of flexible robots. Detailed design of helix parameters, simulation and verification experiments were performed. We have shown the feasibility of helical configuration to reduce the effect of temperature, and detect the torsion and bending of the flexible shaft. The experimental results demonstrated the potential to provide a shape detection for flexible robot.
Autors: Junbo Wei;Shuxin Wang;Jinhua Li;Siyang Zuo;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6627 - 6636
Publisher: IEEE
 
» Novel Method for Predicting Limit Performance of Bus-Transfer Switching by Disconnectors
Abstract:
In order to accurately predict the performance of disconnectors conducting bus-transfer switching in gas insulated substations, the influencing factors of the switching process itself as well as the reignition characteristics need to be analyzed. For this, an LC-oscillating ac current source in combination with a nonstandardized full bus-transfer loop was built. Based on experiment data from a total of 347 reignitions and 570 extinctions, the reignition characteristic of the disconnector at current zero was investigated. Thereby, the derivation of a reignition criterion depending exclusively on the prediction of the instantaneous recovery voltage and the prospective arc voltage was possible. Using this criterion, time-dependent simulations of the bus-transfer process can be made to predict the performance of disconnectors for a wide variety of scenarios such as worst case bus-transfer current for varying circuit parameters and ratings. This minimizes the need for extensive testing during substation planning or disconnector development.
Autors: Andreas Ritter;Ueli Straumann;Christian Michael Franck;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Oct 2017, volume: 32, issue:5, pages: 2210 - 2217
Publisher: IEEE
 
» Novel Programmable Passive Intermodulation Generator Using Nonlinear Rotating Disk
Abstract:
This letter presents a programmable passive intermodulation (PIM) generator with 50-dB-dynamic range using nonlinear mechanical rotating disk. Its implementation is based on a strip-line structured configuration; a nickel-plated disk is inserted into polytetrafluoroethylene substrate through the slots on upper and central conductor. The partly nickel coated copper disk works as an artificial nonlinear sources. Through rotating this disk using stepper motor controlled by micro control unit, PIM product can be automatically tuned by regulating the electromagnetic exposure area on the nickel-plated region. A rational PIM quantization method for nickel-plated nonlinear region is propounded. The experiments demonstrate this PIM generator can perform controllable PIM level, ranges from −127 to −77.4 dBm at dBm, while its finest step can be smaller than 0.3 dB. This letter demonstrates a solution to realize a tunable PIM standard for potential PIM dynamic calibration application.
Autors: Xiong Chen;Yongning He;
Appeared in: IEEE Microwave and Wireless Components Letters
Publication date: Oct 2017, volume: 27, issue:10, pages: 945 - 947
Publisher: IEEE
 
» Novel Reception and Transmission Calibration Technique for Active Antenna Array Based on Phase Center Estimation
Abstract:
This paper presents an on-site calibration technique and significant results obtained from the compensation of errors and mutual coupling. The proposed algorithm deals with the problem of calibration of active antenna arrays at reception and transmission, proposing an on-site calibration technique. The proposed on-site calibration technique starts with the application of an off-line calibration algorithm of which two different techniques are proposed. These techniques are based on the direct estimation of the phase center from the active element pattern measured, and the phase center estimation based on the active element pattern suggested. The expansion of equations of the proposed off-line calibration algorithms is also presented. These algorithms deal with the compensation of mutual coupling effect and together with gain, phase, and location errors.
Autors: Miguel A. Salas-Natera;Ramón Martínez Rodríguez-Osorio;Leandro de Haro Ariet;Manuel Sierra-Pérez;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5511 - 5522
Publisher: IEEE
 
» Novel Solutions of a Delta–Sigma-Based Rectifying Encoder
Abstract:
This brief presents novel low-complexity designs of rectifying encoders for direct processing of the first-order delta–sigma modulated pulse streams. The first solution consists of a D flip-flop and an XOR gate. The second solution incorporates a sign detector. Our results are compared and contrasted with theory and with results found in the literature such as waveform shapes and signal-to-noise ratios. Analytical models, numerical simulations, and experimental measurement results are presented.
Autors: Djuro Zrilic;Grozdan Petrovic;Wei Tang;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Oct 2017, volume: 64, issue:10, pages: 1242 - 1246
Publisher: IEEE
 
» Novel Structure for Area-Efficient Implementation of FIR Filters
Abstract:
It is observed that in multiplierless implementation of transposed direct form finite impulse response (FIR) filters, the adders in the product-accumulation block, which are called structural adders (SAs), contribute the major part of the overall logic complexity. A novel FIR filter structure is therefore proposed to reduce the hardware complexity of the product-accumulation block. In the proposed structure, half of the long word-length SAs are replaced by adders, which are called pre-SAs, which have a relatively shorter word length. The filter coefficients are carefully grouped to take advantage of the symmetric impulse response of linear phase FIR filters. Analysis and experimental results show that the overall area complexity and power consumption can be reduced at the expense of negligible delay overhead. The average area and power reduction over existing techniques can be as much as 23.8% and 25.4%. The overall area-delay performance and power-delay performance of the proposed implementation is superior to existing techniques.
Autors: Xin Lou;Pramod Kumar Meher;Yajun Yu;Wenbin Ye;
Appeared in: IEEE Transactions on Circuits and Systems II: Express Briefs
Publication date: Oct 2017, volume: 64, issue:10, pages: 1212 - 1216
Publisher: IEEE
 
» Novel TDR Test Method for Diagnosis of Interconnect Failures Using Automatic Test Equipment
Abstract:
This paper suggests a novel efficient interconnect failure diagnosis method, which is dubbed as “time of propagation delay pass fail (TPDPF),” employing time domain reflectometry (TDR). The proposed TPDPF has been applied to diagnose the interconnect failures in a high parallelism probe card with the TDR function of automatic test equipment (ATE), which has been exclusively used in calibrating the channel length skews. It has been shown that the TPDPF method could be very efficient in the diagnosis of the interconnect failures with the help of a short-end fixture (a metal wafer), which is also proposed in this paper. To check the validity of the proposed TPDPF method, an automatic probe card diagnosis system was constructed, and it turned out to take only a few minutes to diagnose the whole interconnects in a high parallelism probe card. Furthermore, the implemented diagnosis system does not require skilled hands due to its automatic execution, and it enables about a enhancement of the efficiency of the probe card management and wafer testing.
Autors: Gyu-Yeol Kim;Shin-Ho Kang;Wansoo Nah;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2638 - 2646
Publisher: IEEE
 
» Novel Three-Point Interpolation DFT Method for Frequency Measurement of Sine-Wave
Abstract:
This paper proposes a novel three-point interpolation discrete Fourier transform for accurate power system frequency measurement. The accurate formula of the proposed frequency measurement method is derived by using the maximum sidelobe decay windows. Moreover, the influence of white noise on the proposed frequency measurement is analyzed by deducing the expression of frequency measurement variance. The systematic errors and variances of frequency measurement are analyzed by simulation.
Autors: He Wen;Chengcheng Li;Lu Tang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2333 - 2338
Publisher: IEEE
 
» Novel Trust Framework for Vehicular Networks
Abstract:
Dedicated short range communication is proposed for vehicle to vehicle communications to learn about significant events in the network from neighboring vehicles. However, these neighbors may be malicious and report incorrect events in order to take advantage of the system. The malicious nodes may also provide incorrect recommendations about their peers in order to exert a stronger influence on the receiver's decision. Incorrect information and malicious nodes render the system unreliable for safety and emergency applications. In order to correctly identify the events as well as malicious nodes, a novel trust framework is proposed in this paper that studies all aspects of the trust in connected vehicle (CV) to CV communications. The nodes iteratively learn about the environment from received messages and then update the trust values of their neighbors. Nodes are classified on the basis of their trust values and reported events are also classified as true and false. Nodes advertise their recommendation about trusted and malicious neighbors. The proposed framework allows nodes to identify and filter recommendations from malicious nodes, and to discern true events. The performance of the proposed framework is evaluated experimentally using false and true positive rates, event detection probability and trust computation error. The proposed framework identifies malicious nodes and true events with high probability of more than 0.92 while keeping the trust computation error below 0.03.
Autors: Saneeha Ahmed;Sarab Al-Rubeaai;Kemal Tepe;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9498 - 9511
Publisher: IEEE
 
» Number-Theoretic Sequence Design for Uncoordinated Autonomous Multiple Access in Relay-Assisted Machine-Type Communications
Abstract:
Terminal relaying is expected to offer an effective means for realizing machine-type communications (MTC) in wireless cellular networks. In the absence of channel quality indicators, the effective utilization of relaying terminals (RTs) requires a mechanism by which RTs can autonomously assign available resource blocks (RBs) to potentially large numbers of uncoordinated MTC devices with minimal conflicts. Unlike random RB assignments, which do not offer performance guarantees, using prescribed RB assignment sequences provides an opportunity for obtaining performance gains. However, realizing these gains requires optimizing RB assignments over a large set of lengthy sequences. One technique for selecting assignment sequences is based on an exhaustive search of exponential complexity over sequences generated by multiplicative cyclic groups. This technique restricts the number of RBs to be prime minus one and does not consider sequences generated using other group operations. In this paper, we use group isomorphism to eliminate the constraint on the number of RBs and to show that the optimal assignment sequences generated by a specific cyclic group are globally optimal over the set of all cyclically generated sequences. We develop a greedy algorithm with polynomial complexity for the sequential selection of RB assignment sequences in systems with large numbers of RTs and arbitrary device distributions. This algorithm is further simplified by invoking the graphical representation of cyclic groups. The resulting algorithm is more efficient and thus suitable for generating assignment sequences for relay-assisted massive multiple access Internet-of-Things systems. Numerical results show that the performance of the sequences generated by the greedy algorithms is comparable to that of those generated by exhaustive search, but with much less computational cost.
Autors: Yaser M. M. Fouad;Ramy H. Gohary;Halim Yanikomeroglu;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9018 - 9034
Publisher: IEEE
 
» Numerical Analysis of Electromagnetic Scattering From a Moving Target by the Lorentz Precise Integration Time-Domain Method
Abstract:
A novel numerical method, referred to as Lorentz precise integration time-domain (Lorentz-PITD) method, is proposed to deal with the scattering problem from a moving conducting slab. Both the overset grid generation technique and the Lorentz transformation are employed in this method. By using the Lorentz transformation and the linear interpolation technique, the incident plane wave in the rest frame is introduced to the moving frame; the scattered fields are transformed from the moving frame to the rest frame. Numerical experiments validate the Lorentz-PITD method and show that the Lorentz-PITD method is more computationally efficient compared with the Lorentz finite-difference time-domain method. An accompanied find is that there must be a tradeoff between the applicable frequency range and the computation cost in the proposed method.
Autors: Jinghui Shao;Xikui Ma;Zhen Kang;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5649 - 5653
Publisher: IEEE
 
» Numerical Analysis of Large-Scale Finite Periodic Arrays Using a Macro Block-Characteristic Basis Function Method
Abstract:
Numerical analysis of a large-scale finite periodic array is accurate but quite costly when the array is analyzed as a finite array. The computational cost for the numerical analysis can be reduced greatly when the array is approximated as an infinite periodic structure. However, the edge effect that strongly affects the active impedance or current distribution of the array elements near the edge is neglected. In this paper, a macro block-characteristic basis function method (MB-CBFM) for numerical analysis of a large-scale finite periodic array with a uniform amplitude and linear phased excitation is proposed. The MB-CBFM utilizes blocks and macro blocks to group the elements in order to reduce its computational cost without degrading accuracy. Numerical simulations demonstrate that the CPU time and computer memory of the MB-CBFM are when the size of array is sufficiently large.
Autors: Keisuke Konno;Qiang Chen;Robert J. Burkholder;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5348 - 5355
Publisher: IEEE
 
» Numerical Modeling and High-Speed Parallel Computing: New Perspectives on Tomographic Microwave Imaging for Brain Stroke Detection and Monitoring.
Abstract:
This article deals with microwave tomography for brain stroke imaging using state-of-the-art numerical modeling and massively parallel computing. Iterative microwave tomographic imaging requires the solution of an inverse problem based on a minimization algorithm (e.g., gradient based) with successive solutions of a direct problem such as the accurate modeling of a whole-microwave measurement system. Moreover, a sufficiently high number of unknowns is required to accurately represent the solution. As the system will be used for detecting a brain stroke (ischemic or hemorrhagic) as well as for monitoring during the treatment, the running times for the reconstructions should be reasonable. The method used is based on high-order finite elements, parallel preconditioners from the domain decomposition method and domain-specific language with the opensource FreeFEM++ solver.
Autors: Pierre-Henri Tournier;Marcella Bonazzoli;Victorita Dolean;Francesca Rapetti;Frederic Hecht;Frederic Nataf;Iannis Aliferis;Ibtissam El Kanfoud;Claire Migliaccio;Maya de Buhan;Marion Darbas;Serguei Semenov;Christian Pichot;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 98 - 110
Publisher: IEEE
 
» Numerical Simulation of the SGEMP Inside a Target Chamber of a Laser Inertial Confinement Facility
Abstract:
After X-ray irradiate a metal cavity, a large number of photoelectrons are emitted into the internal space, thereby producing a very strong system-generated electromagnetic pulse (SGEMP). The X-ray environment inside a laser inertial confinement device is very complex. Even if the diagnostic equipment working inside the target chamber has a good electromagnetic shielding capability, it would still face severe SGEMP interference. In this paper, the X-ray environments inside target chambers of National Ignition Facility, optimized method for estimated guidance accuracy (OMEGA), and Shenguang-III (SG-III) facility were obtained through a survey of the literature. In light of the survey results, the time-biased finite-difference time-domain method and the particle-in-cell method were used to numerically simulate SGEMP inside a 2-D cylindrical cavity model. Besides, the relationships between the SGEMP in the cavity and parameters such as X-ray fluence, energy spectrum, pulsewidth, and spatial size of the model were studied. The fluence and pulsewidth of the X-ray were found to have a more significant effect on the time-domain waveform of the electromagnetic field. Finally, based on the calculation results, the SGEMP of the SG-III facility in the target chamber was calculated to approximately be 0.75 MV/m.
Autors: Meng Cui;Xu Zhiqian;Jiang Yunsheng;Zheng Wanguo;Dang Zhao;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Oct 2017, volume: 64, issue:10, pages: 2618 - 2625
Publisher: IEEE
 
» Numerical Temperature Analysis of Magnetic Hyperthermia Considering Nanoparticle Clustering and Blood Vessels
Abstract:
Magnetic fluid hyperthermia can ablate malignant cells by using heat from magnetic nanoparticles (MNPs) when subjected to an alternating magnetic field. In comparison with other types of MNPs, the ones with low Curie temperature (LCT) have the characteristic of temperature self-regulation, which contributes to its choice for hyperthermia therapy. To validate the advantages of LCT MNPs over MNPs with high Curie temperature, this paper proposes a complex geometric model based on the prototype of a human liver, in which blood vessels (BVs) and nanoparticle clustering are considered. In this paper, the temperature fields of tumor tissue with different MNPs are predicted by solving the Pennes bioheat transfer equation, while the effect of BVs is taken into account by solving the Navier–Stokes equation. Simulation results demonstrate that MNP systems with LCT can have better therapeutic effect than the Fe3O4 MNPs if the power dissipation is increased with respect to its critical value. Higher thermal energy absorbing from magnetic field not only increases the uniformity of the temperature field, but also can shorten the startup time in MNP systems with LCT, which does not occur in Fe3O4 MNPs systems. Such advantages of LCT MNPs are observed for minimizing the undesirable effects of both BVs and MNP clustering.
Autors: Yundong Tang;Tao Jin;Rodolfo C. C. Flesch;
Appeared in: IEEE Transactions on Magnetics
Publication date: Oct 2017, volume: 53, issue:10, pages: 1 - 6
Publisher: IEEE
 
» NVM Way Allocation Scheme to Reduce NVM Writes for Hybrid Cache Architecture in Chip-Multiprocessors
Abstract:
Hybrid cache architectures (HCAs) containing both SRAM and non-volatile memory (NVM) have been proposed to overcome the disadvantages of NVM-based cache architecture. Most previous works have concentrated on managing write-intensive blocks by storing these blocks to SRAM to reduce the number of the write operations to NVM. However, they have not focused on reducing linefill operations which also occupy a large portion of overall NVM write counts in chip-multiprocessor (CMP) environments. This paper proposes an NVM way allocation scheme, taking into account the NVM linefill counts as well as cache miss rate and the NVM write hit counts during victim selection. Three metrics are introduced to estimate the effectiveness of NVM way allocation: Miss counts change (), write counts change (), and NVM write counts change (). An algorithm to minimize the write counts of NVM based on these metrics is proposed as well. Our experimental results show that dynamic energy consumption is reduced by 37.5 percent on average.
Autors: Ju-Hee Choi;Gi-Ho Park;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2896 - 2910
Publisher: IEEE
 
» Observations of Water Column and Bathymetric Effects on the Incident Acoustic Field Associated With Shallow-Water Reverberation Experiments
Abstract:
As a part of the 2013 Targets and Reverberation Experiment (TREX13), measurements of the acoustic field generated by a source used in midfrequency (1.8–3.6 kHz) reverberation experiments are studied at 5 and 6 km range. The TREX13 reverberation sources were placed off the coast of Panama City, FL, USA, in waters ∼20 m deep, and data discussed here are from a 2-h period in the late afternoon on April 28, 2013. The observed coda of the source signal is partitioned into an initial primary arrival, and a distinct second arrival delayed by roughly 2 s. Characteristics of the two arrivals are studied in terms of the effective number of modes, interference features, and the direction of acoustic intensity, which was directly measured by a vector sensor located at 5 km range. A shift in frequency within the primary arrival is observed over the 2-h measurement period. Frequency shifts are related to a change in range of dislocations, defined as points of complete destructive interference in the acoustic field, that modulate with tidal variation in the sound-speed profile. Precise frequencies are identified with the vector property called circularity, a nondimensional measure of acoustic intensity curl, that is maximal within the vortex-like intensity field within a dislocation. Using the waveguide invariant β, the frequency shift is used to estimate the tidal change in the thermocline depth. These interference features are absent in the second arrival, which is postulated to be an acoustic path horizontally refracted by the gently sloping bathymetry (∼0.4°) forming the coastal environment. A description of the refraction using modal rays is developed, and the transition of the mode from being trapped to leaky is handled as a transition to a virtual mode near the cutoff depth. Models of the primary and refracted arrivals are presented to support the conclusions.
Autors: David R. Dall'Osto;Peter H. Dahl;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 1146 - 1161
Publisher: IEEE
 
» Observer-Based Fault-Tolerant Attitude Control for Rigid Spacecraft
Abstract:
This paper addresses the problem of robust fault-tolerant control of spacecraft attitude stabilization in the presence of model uncertainties, actuator failures, and external disturbances simultaneously. Utilizing the fast nonsingular terminal sliding mode control technique, a novel finite-time extended state observer is first proposed to estimate and compensate for the specified synthetic uncertainties derived from actuator failures and/or model deviations. And also the detailed derivations of the observer are provided, along with a thorough analysis for the associated ultimately bounded stability and estimation error convergence property in the sense of finite-time control. Then, with the reconstructed information achieving from the finite-time observer, an adaptive robust sliding mode based fault-tolerant control approach is developed to ensure that the closed-loop attitude control system reach the real sliding mode surface in finite time. Meanwhile, the chattering problem has been restrained via the modified gain adjusting law. The key feature of the proposed strategies is that the whole closed-loop fault-tolerant control system can be guaranteed theoretically to be finite-time stable by the development of Lyapunov methodology. Finally, numerical simulation results are presented to illustrate and highlight the fine performance benefits obtained using the proposed schemes.
Autors: Bo Li;Qinglei Hu;Yanbo Yu;Guangfu Ma;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2572 - 2582
Publisher: IEEE
 
» Obtaining Significant and Interpretable Rules for Subgroup Discovery Tasks
Abstract:
In this work, a deterministic method to obtain rules for subgroup discovery tasks is described. It does not employ a previous discretization for the numeric attributes, but obtains conditions for the rules dynamically. To select the final rules, the equivalent sum of sensitivity and specificity has been used. An experimental study and appropriate statistical tests were performed, in a comparison with the classic deterministic algorithms APRIORI-SD and CN2-SD. The proposed method behaved very well, obtaining the best results in six of the eight pair-wise comparisons. From the results obtained, the described approach can be seen as a suitable deterministic way of extracting rules for subgroup discovery problems.
Autors: Juan Luis Dominguez Olmedo;Jacinto Mata Vazquez;
Appeared in: IEEE Latin America Transactions
Publication date: Oct 2017, volume: 15, issue:10, pages: 2012 - 2016
Publisher: IEEE
 
» Occlusion-Model Guided Antiocclusion Depth Estimation in Light Field
Abstract:
Occlusion is one of the most challenging problems in depth estimation. Previous work has modeled the single-occluder occlusion in light field and achieves good performances, however it is still difficult to obtain accurate depth for multioccluder occlusion. In this paper, we explore the complete occlusion model in light field and derive the occluder-consistency between the spatial and angular spaces, which is used as a guidance to select unoccluded views for each candidate occlusion point. Then, an antiocclusion energy function is built to regularize the depth map. Experimental results on both synthetic and real light-field datasets have demonstrated the advantages of the proposed algorithm compared with state-of-the-art algorithms of light-field depth estimation, especially in multioccluder cases.
Autors: Hao Zhu;Qing Wang;Jingyi Yu;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Oct 2017, volume: 11, issue:7, pages: 965 - 978
Publisher: IEEE
 
» OFDM-Based Interference Alignment in Single-Antenna Cellular Wireless Networks
Abstract:
Interference alignment (IA) is widely regarded as a promising interference management technique in wireless networks. Despite its rapid advances in cellular networks, most results of IA are limited to information-theoretic exploration or physical-layer signal design. Little progress has been made so far to advance IA in cellular networks from a networking perspective. In this paper, we aim to fill this gap by studying IA in large-scale cellular networks. For the uplink, we propose an OFDM-based IA scheme and prove its feasibility at the physical layer by showing that all data streams in the IA scheme can be transported free of interference. Based on the IA scheme, we develop a cross-layer IA optimization framework that can fully translate the benefits of IA to throughput gain in cellular networks. Furthermore, we show that the IA optimization problem in the downlink can be solved in the exactly same way as that in the uplink. Simulation results show that our OFDM-based IA scheme can significantly increase the user throughput and the throughput gain increases with user density in the network.
Autors: Huacheng Zeng;Yi Shi;Y. Thomas Hou;Wenjing Lou;Xu Yuan;Rongbo Zhu;Jiannong Cao;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4492 - 4506
Publisher: IEEE
 
» OFDM-Like Signaling for Broadband Satellite Applications: Analysis and Advanced Compensation
Abstract:
Orthogonal frequency-division multiplexing (OFDM), special form of multicarrier modulation, is the cornerstone of broad range of current standards. In addition, fifth-generation (5G) terrestrial wireless networks, advancing at accelerated speed, continue to use OFDM air interface. The first part of this paper endeavors to apply OFDM-like signaling for broadband satellite transmission in the forward direction, from gateway to terminals. Two layers of multicarrier operation are invoked. One allows multiple signals to share single on-board high-power amplifier. The other layer permits transmitted symbols from individual signals to modulate multiple narrowband OFDM subcarriers, followed by interpolating filters to suppress interference into adjacent signals and limit out-of-band emission to be compatible with satellite uplink. The second part of this paper proposes novel nonlinear compensation techniques, applied at the transmitter or receiver, and combination of both. Two performance assessments are provided: one exploiting information-theoretic framework using ideal channel coding; another based on total degradation using practical forward-error correction codes. We show that performance loss from nonlinear distortion can be significantly reduced when adopting the proposed correction methods. Furthermore, it is possible to use OFDM-like signaling over satellite, while being competitive, and in some cases surpassing, traditional systems with single-carrier modulation employing state-of-the-art enhanced receiver architecture.
Autors: Bassel F. Beidas;Rohit Iyer Seshadri;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4433 - 4445
Publisher: IEEE
 
» Offloading Collective Operations to Programmable Logic
Abstract:
The authors describe their architecture and implementation for offloading collective operations to programmable logic in the communication substrate. Collective operations are widely used in parallel processing. Their design and implementation strategies affect the performance of many high-performance computing applications that utilize them. Collectives are central to the message passing interface (MPI) programming model. The programmable logic provided by field-programmable gate arrays (FPGAs) is a powerful option for creating task-specific logic to aid applications. The authors’ approach is applicable in scenarios where there is programmable logic in the communication pipeline and can be used to accelerate various network-based operations. In this article, the authors present a general collective offloading framework for use in applications using MPI. They evaluate their approach on the Xilinx Zynq system on a chip and an FPGA-based network interface card called the NetFPGA. Results are presented both from microbenchmarks and a benchmark scientific application using MPI.
Autors: Omer Arap;Lucas R.B. Brasilino;Ezra Kissel;Alexander Shroyer;Martin Swany;
Appeared in: IEEE Micro
Publication date: Oct 2017, volume: 37, issue:5, pages: 52 - 60
Publisher: IEEE
 
» Offloading in HCNs: Congestion-Aware Network Selection and User Incentive Design
Abstract:
To accommodate exponentially increasing traffic demands, operators are seeking to offload cellular traffic to small base stations (BSs) in heterogeneous cellular networks (HCNs), which is promising in alleviating traffic congestion. In HCNs, operators are eager to balance the traffic globally, where users may be pushed to less preferred small BSs, resulting in possible conflict with user local preference. Thus, it is a big challenge to achieve dynamic load balancing for operators and provide participation incentive for users simultaneously. Due to the dynamics of network state and user traffic demand, we are inspired to utilize Lyapunov optimization to develop a congestion-aware cellular offloading scheme. Specifically, an operator profit maximization problem involving network selection and rate control is formulated. To achieve long-term network stability, we propose a congestion-aware network selection algorithm, obtaining the BS alternative set that maintains traffic congestion constraint. By exploring the heterogeneity of user quality sensitivity, we devise the optimal quality-price contract, which maximizes operator profit. With effective pricing and resource allocation, users are motivated to make proper association strategy chosen from the BS alternative set. Simulation results demonstrate the effectiveness of our scheme in improving operator profit. User incentive and network stability are also validated.
Autors: Yuqing Li;Bingyu Shen;Jinbei Zhang;Xiaoying Gan;Jingchao Wang;Xinbing Wang;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6479 - 6492
Publisher: IEEE
 
» Offset Aperture-Coupled Double-Cylinder Dielectric Resonator Antenna With Extended Wideband
Abstract:
A compact dielectric resonator antenna for ultrawideband vehicular communication applications is proposed. Two cylindrical dielectric resonators are asymmetrically located with respect to the center of an offset rectangular coupling aperture, through which they are fed. Optimizing the design parameters results in an impedance bandwidth of 21%, covering the range from 5.9 to 7.32 GHz in the lower band and a 53% relative bandwidth from 8.72 to 15 GHz in the upper band. The maximum achieved gain is 12 dBi. Design details of the proposed antenna and the results of both simulations and experiment are presented and discussed.
Autors: C.-E. Zebiri;M. Lashab;D. Sayad;I. T. E. Elfergani;K. H. Sayidmarie;F. Benabdelaziz;R. A. Abd-Alhameed;J. Rodriguez;J. M. Noras;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5617 - 5622
Publisher: IEEE
 
» Offshore Metallic Platforms Observation Using Dual-Polarimetric TS-X/TD-X Satellite Imagery: A Case Study in the Gulf of Mexico
Abstract:
Satellite-based synthetic aperture radar (SAR) has been proven to be an effective tool for ship monitoring. Offshore platforms monitoring is a key topic for both safety and security of the maritime domain. However, the scientific literature oriented to the observation of offshore platforms using SAR imagery is very limited. This study is mostly focused on the analysis and understanding of the multipolarization behavior of platforms’ backscattering using dual-polarization X-band SAR imagery. This study is motivated by the fact that under low incidence angle and moderate wind conditions, copolarized channels may fail in detecting offshore platforms even when fine-resolution imagery is considered. This behavior has been observed on both medium- and high-resolution TerraSAR-X/TanDEM-X SAR imagery, despite the fact that platforms consist of large metallic structures. Hence, a simple multipolarization model is proposed to analyze the platform backscattering. Model predictions are verified on TerraSAR-X/TanDEM-X SAR imagery, showing that for acquisitions under low incidence angle, the platforms result in a reduced copolarized backscattered intensity even when fine resolution imagery is considered. Finally, several solutions to tackle this issue are proposed with concluding remark that the performance of offshore observation.
Autors: Armando Marino;Domenico Velotto;Ferdinando Nunziata;
Appeared in: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing
Publication date: Oct 2017, volume: 10, issue:10, pages: 4376 - 4386
Publisher: IEEE
 
» On a Low-Frequency and Refinement Stable PMCHWT Integral Equation Leveraging the Quasi-Helmholtz Projectors
Abstract:
Classical Poggio–Miller–Chan–Harrington–Wu–Tsai (PMCHWT) formulations for modeling radiation and scattering from penetrable objects suffer from ill-conditioning when the frequency is low or when the mesh density is high. The most effective techniques to solve these problems, unfortunately, either require the explicit detection of the so-called global loops of the structure, or suffer from numerical cancellation at extremely low frequency. In this contribution, a novel regularization method for the PMCHWT equation is proposed, which is based on the quasi-Helmholtz projectors. This method not only solves both the low frequency and the dense mesh ill-conditioning problems of the PMCHWT, but it is immune from low-frequency numerical cancellations and it does not require the detection of global loops. This is obtained by projecting the range space of the PMCHWT operator onto a dual basis, by rescaling the resulting quasi-Helmholtz components, by replicating the strategy in the dual space, and finally, by combining the primal and the dual equations in a Calderón-like fashion. Implementation-related treatments and details alternate the theoretical developments in order to maximize impact and practical applicability of the approach. Finally, numerical results corroborate the theory and show the effectiveness of the new schemes in real case scenarios.
Autors: Yves Beghein;Rajendra Mitharwal;Kristof Cools;Francesco P. Andriulli;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5365 - 5375
Publisher: IEEE
 
» On Combining Social Media and Spatial Technology for POI Cognition and Image Localization
Abstract:
With fast development of information engineering and social network, people’s locations can be conveniently sensed by spatial technology, such as global positioning systems (GPS), base stations, Wi-Fi access points and even from the appearances of the photos they have taken. The social networks and the online shopping platforms have been gathering billions of users, who share a large amount of images taken in places they live in and visit. We can leverage the social networks to express our opinions about the services and places of interest (POIs). The interactions among users, and user and POIs or services generate big social media data, which have rich information for user, location, and service cognition. Many real-time network applications rely heavily on the accurate social users’ locations. How to sense the locations from multisource social media data is very important and challenging. Thus, in this paper, we give a systematic review of the works that combine social media and spatial technology for POI cognition and image localization.
Autors: Xueming Qian;Xiaoqiang Lu;Junwei Han;Bo Du;Xuelong Li;
Appeared in: Proceedings of the IEEE
Publication date: Oct 2017, volume: 105, issue:10, pages: 1937 - 1952
Publisher: IEEE
 
» On Developing One-Chip Integration of 1.2 kV SiC MOSFET and JBS Diode (JBSFET)
Abstract:
This paper presents the design, fabrication, and characterization of the SiC JBSFET (junction barrier Schottky (JBS) diode integrated MOSFET). The fabrication of the JBSFET adopted a novel single metal, single thermal treatment process to simultaneously form ohmic contacts on n+, p+ implanted regions, and Schottky contact on the n-4H-SiC epilayer. The presented SiC JBSFET uses 40% smaller wafer area because the diode and MOSFET share the edge termination as well as the current conducting drift region. The proposed single chip solution of MOSFET/JBS diode functionalities eliminates the parasitic inductance between separately packaged devices allowing a higher frequency operation in a power converter.
Autors: Woongje Sung;B. J. Baliga;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8206 - 8212
Publisher: IEEE
 
» On Dual-Band Amplifications Using Dual Two-Tones: Clarifications and Discussion
Abstract:
A significant development of recent research in nonlinear distortion is the expansion of the conventional two-tone test for power amplifiers to the concurrent dual-band transmitters, by Amin et al. A general framework using dual two-tones is developed, which shows that the output signal is affected not only by intermodulation (IM) products but also by cross-modulation (CM) products. In this paper, we will make a number of clarifications to Amin et al.’s paper. The effects of IM and CM in passband will be discussed, IM represents a reduction for compressive devices, and CM reflects an interference caused by the signal from the other band, and followed by the analysis of out-of-band IM. It was concluded that out-of-band IM needs to be taken into consideration for the design of power amplifiers when two bands are very close.
Autors: Siyuan Yan;Xianzhen Yang;Xiao Li;Fu Li;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2792 - 2794
Publisher: IEEE
 
» On Efficient and Robust Anonymization for Privacy Protection on Massive Streaming Categorical Information
Abstract:
Protecting users' privacy when transmitting a large amount of data over the Internet is becoming increasingly important nowadays. In this paper, we focus on the streaming categorical information and propose a novel anonymization technique for providing a strong privacy protection to safeguard against privacy disclosure and information tampering. Our technique utilizes an innovative two-phase anonymization approach which is very easy to implement, highly efficient in terms of speed and communication and is robust against possible tampering from adversaries. Extensive experimental evaluation that is conducted demonstrates that our technique is very efficient and more robust than the existing method.
Autors: Ji Zhang;Hongzhou Li;Xuemei Liu;Yonglong Luo;Fulong Chen;Hua Wang;Liang Chang;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Oct 2017, volume: 14, issue:5, pages: 507 - 520
Publisher: IEEE
 
» On Existence of Equilibria of Multi-Port Linear AC Networks With Constant-Power Loads
Abstract:
In this paper we give an answer to the following question. Given a multi-port, linear ac network with instantaneous constant-power loads identify a set of active and reactive load powers for which there is no steady-state operating condition of the network—in this case, we say that the power load is inadmissible. The identification is given in terms of feasibility of simple linear matrix inequalities, and hence it can be easily verified with existing software. For one- or two-port networks, the proposed feasibility test is necessary and sufficient for load power admissibility with the test for the former case depending only on the network data. Two benchmark numerical examples illustrate our results.
Autors: Juan E. Machado;Robert Griñó;Nikita Barabanov;Romeo Ortega;Boris Polyak;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Oct 2017, volume: 64, issue:10, pages: 2772 - 2782
Publisher: IEEE
 
» On Feasibility of Interference Alignment in Full-Duplex-Based Small Cell Networks
Abstract:
As an appealing interference management approach, interference alignment (IA) has not been intensively studied in full-duplex (FD)-based multi-cells. In this letter, based on Bezout’s theorem, we explore the feasibility conditions of IA in small cell networks, where base stations are equipped with FD hardware. The comparison of IA performance between FD and traditional half-duplex small cells in terms of the total degrees of freedom (DoFs) is also conducted. We find that the IA performance with FD is limited by the number of antennas at users. Furthermore, we verify that IA with opportunistic FD can be implemented to achieve higher total DoFs of the network.
Autors: Momiao Zhou;Hongyan Li;Jiandong Li;Long Suo;Weidong Shao;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2294 - 2297
Publisher: IEEE
 
» On Max-SIR Time–Frequency Packing for Multicarrier Faster-Than-Nyquist Signaling
Abstract:
In this letter, a novel maximizing signal-to-interference ratio (max-SIR) time–frequency packing scheme for multicarrier faster-than-Nyquist signaling is proposed. The proposed scheme is based on the low complexity symbol-by-symbol detector. Specifically, we optimize the time–frequency spacing under the given signaling efficiency to maximize the SIR, i.e., the ratio between the energy of useful signal and the intersymbol interference and intercarrier interference introduced by time–frequency packing. We show that the proposed max-SIR time–frequency packing outperforms other time–frequency packing schemes for both the symbol-by-symbol detection and coupled with successive interference cancellation.
Autors: Siming Peng;Aijun Liu;Xinhai Tong;Ke Wang;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2142 - 2145
Publisher: IEEE
 
» On Multiple AER Handshaking Channels Over High-Speed Bit-Serial Bidirectional LVDS Links With Flow-Control and Clock-Correction on Commercial FPGAs for Scalable Neuromorphic Systems
Abstract:
Address event representation (AER) is a widely employed asynchronous technique for interchanging “neural spikes” between different hardware elements in neuromorphic systems. Each neuron or cell in a chip or a system is assigned an address (or ID), which is typically communicated through a high-speed digital bus, thus time-multiplexing a high number of neural connections. Conventional AER links use parallel physical wires together with a pair of handshaking signals (request and acknowledge). In this paper, we present a fully serial implementation using bidirectional SATA connectors with a pair of low-voltage differential signaling (LVDS) wires for each direction. The proposed implementation can multiplex a number of conventional parallel AER links for each physical LVDS connection. It uses flow control, clock correction, and byte alignment techniques to transmit 32-bit address events reliably over multiplexed serial connections. The setup has been tested using commercial Spartan6 FPGAs attaining a maximum event transmission speed of 75 Meps (Mega events per second) for 32-bit events at a line rate of 3.0 Gbps. Full HDL codes (vhdl/verilog) and example demonstration codes for the SpiNNaker platform will be made available.
Autors: Amirreza Yousefzadeh;Mirosław Jabłoński;Taras Iakymchuk;Alejandro Linares-Barranco;Alfredo Rosado;Luis A. Plana;Steve Temple;Teresa Serrano-Gotarredona;Steve B. Furber;Bernabé Linares-Barranco;
Appeared in: IEEE Transactions on Biomedical Circuits and Systems
Publication date: Oct 2017, volume: 11, issue:5, pages: 1133 - 1147
Publisher: IEEE
 
» On Network Footprint of Traffic Inspection and Filtering at Global Scrubbing Centers
Abstract:
Traffic diversion through powerful cloud-based scrubbing centers provides a solution for protecting against various DDoS attacks. In one respect, such a solution enables sanitizing attack traffic close to its source and saves precious resources for the network service provider. Contrarily, the diversion of the inspected traffic toward the scrubbing centers may increase its footprint in the network. The location of the scrubbing centers greatly affects the network resource utilization and, therefore, should be carefully considered in the design of the security service. In this paper, we investigate four deployment strategies and compare their performance on a network of Points-of-Presence and on several router level topologies obtained from the RocketFuel project. The deployment quality was measured using the following criteria: the footprint of the inspected traffic, the redistribution of load on the links, and the increase in communication latency. Our results show that the deployment strategy that is considered to perform well for locating network monitors by maximizing flow coverage results in the worst footprint when traffic diversion is employed. Overall, we show that the deployment strategy that is tailored for traffic filtering is also suitable for traffic monitoring, but not the other way around.
Autors: Polina Zilberman;Rami Puzis;Yuval Elovici;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Oct 2017, volume: 14, issue:5, pages: 521 - 534
Publisher: IEEE
 
» On Performance Modeling for MANETs Under General Limited Buffer Constraint
Abstract:
Understanding the real achievable performance of mobile ad hoc networks (MANETs) under practical network constraints is of great importance for their applications in future highly heterogeneous wireless network environments. This paper explores, for the first time, the performance modeling for MANETs under a general limited buffer constraint, where each network node maintains a limited source buffer of size to store its locally generated packets and also a limited shared relay buffer of size to store relay packets for other nodes. Based on the Queuing theory and birth-death chain theory, we first develop a general theoretical framework to fully depict the source/relay buffer occupancy process in such a MANET, which applies to any distributed MAC protocol and any mobility model that leads to the uniform distribution of nodes’ locations in steady state. With the help of this framework, we then derive the exact expressions of several key network performance metrics, including achievable throughput, throughput capacity, and expected end-to-end delay. We further conduct case studies under two network scenarios and provide the corresponding theoretical/simulation results to demonstrate the application as well as the efficiency of our theoretical framework. Finally, we present extensive numerical results to illustrate the impacts of buffer constraint on the performance of a buffer-limited MANET.
Autors: Jia Liu;Yang Xu;Yulong Shen;Xiaohong Jiang;Tarik Taleb;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9483 - 9497
Publisher: IEEE
 
» On Secondary Control Approaches for Voltage Regulation in DC Microgrids
Abstract:
Centralized or decentralized secondary controller is commonly employed to regulate the voltage drop raised by the primary controller. However, in the case of high capacity microgrids (MGs) and long feeders with much voltage drop on the line resistances, the conventional methods may not guarantee the voltage regulation on the load busses within a suitable range. Therefore, in addition to compensate the voltage drop of the primary controller, it is necessary to regulate the voltage of critical loads. In this paper, a new voltage regulation strategy is proposed to regulate the voltage of MG by employing the average voltage of identified critical busses, which are determined by the proposed modal analysis. Numerical steady-state analysis and preliminary simulation results validate effectiveness of the proposed scheme. Furthermore, experimental results are performed to demonstrate the viability of the proposed approach.
Autors: Saeed Peyghami;Hossein Mokhtari;Pooya Davari;Poh Chiang Loh;Frede Blaabjerg;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4855 - 4862
Publisher: IEEE
 
» On Synchronous and Asynchronous Discrete Time Heterogeneous Cyclic Pursuit
Abstract:
This paper considers synchronous and asynchronous heterogeneous cyclic pursuit in discrete time and obtains results on the consensus of both. It is shown that agents in synchronous heterogeneous cyclic pursuit system can achieve consensus with at most one negative gain, subject to a lower limit, which expands the reachable set although the asynchronous case may diverge when one of the agents has a negative gain. However, when all the gains are positive, positional consensus is achieved even in the asynchronous mode. The theoretical results are illustrated through simulations.
Autors: Dwaipayan Mukherjee;Debasish Ghose;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5248 - 5253
Publisher: IEEE
 
» On the Achievable Rate of Bistatic Modulated Rescatter Systems
Abstract:
In ambient rescatter communications, devices convey information by modulating and rescattering the radio frequency signals impinging on their antennas. In this correspondence, we consider a system consisting of a legacy modulated continuous carrier multiple-input-multiple-output link and a multiantenna modulated rescatter (MRS) node, where the MRS node modulates and rescatters the signal generated by the legacy transmitter. The receiver seeks to decode both the original message and the information added by the MRS. We show that the achievable sum rate of this system exceeds that which the legacy system could achieve alone. We further consider the impact of channel estimation errors under the least squares channel estimation and study the achievable rate of the legacy and MRS systems, where a linear minimum mean square error receiver with successive interference cancellation is utilized for joint decoding.
Autors: Ruifeng Duan;Riku Jäntti;Hüseyin Yiğitler;Kalle Ruttik;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9609 - 9613
Publisher: IEEE
 
» On the Complexity of Optimal Power Allocation in a Multi-Tone Multiuser Communication System
Abstract:
Consider a multi-tone multi-user communication system with interfering users and available tones. An effective approach to mitigate interference is through power control at transmitters. In this paper, we consider optimal power allocation to maximize a system utility function, and show that for the two tone cases () with min-rate, harmonic mean, and geometric mean utility functions, the corresponding optimal power allocation problem is NP-hard. This result fills an important gap in the existing literature, which settled the complexity status of different cases involving various utility functions and values of . Our proof is through a reduction from the partitioning problem for the min-rate utility function, and from the independent set problem for the harmonic mean and geometric mean utility functions.
Autors: Marco Locatelli;Zhi-Quan Luo;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6622 - 6627
Publisher: IEEE
 
» On the Consensus of Homogeneous Multiagent Systems With Positivity Constraints
Abstract:
This paper investigates the consensus problem for multiagent systems, under the assumptions that the agents are homogeneous and described by a single-input positive state-space model, the mutual interactions are cooperative, and the static state-feedback law that each agent adopts to achieve consensus preserves the positivity of the overall system. Necessary conditions for the problem solvability, which allow us to address only the special case when the state matrix is irreducible, are provided. Under the irreducibility assumption, equivalent sets of sufficient conditions are derived. Special conditions either on the system description or on the Laplacian of the communication graph allow us to obtain necessary and sufficient conditions for the problem solvability. Finally, by exploiting some results about robust stability either of positive systems or of polynomials, further sufficient conditions for the problem solvability are derived. Numerical examples illustrate the proposed results.
Autors: Maria Elena Valcher;Irene Zorzan;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5096 - 5110
Publisher: IEEE
 
» On the Design of Secure Non-Orthogonal Multiple Access Systems
Abstract:
This paper proposes a new design of non-orthogonal multiple access (NOMA) under secrecy considerations. We focus on a NOMA system, where a transmitter sends confidential messages to multiple users in the presence of an external eavesdropper. The optimal designs of decoding order, transmission rates, and power allocated to each user are investigated. Considering the practical passive eavesdropping scenario where the instantaneous channel state of the eavesdropper is unknown, we adopt the secrecy outage probability as the secrecy metric. We first consider the problem of minimizing the transmit power subject to the secrecy outage and quality of service constraints, and derive the closed-form solution to this problem. We then explore the problem of maximizing the minimum confidential information rate among users subject to the secrecy outage and transmit power constraints, and provide an iterative algorithm to solve this problem. We find that the secrecy outage constraint in the studied problems does not change the optimal decoding order for NOMA, and one should increase the power allocated to the user whose channel is relatively bad when the secrecy constraint becomes more stringent. Finally, we show the advantage of NOMA over orthogonal multiple access in the studied problems both analytically and numerically.
Autors: Biao He;An Liu;Nan Yang;Vincent K. N. Lau;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Oct 2017, volume: 35, issue:10, pages: 2196 - 2206
Publisher: IEEE
 
» On the Estimation of Ground and Volume Polarimetric Covariances in Forest Scenarios With SAR Tomography
Abstract:
A two-layer model composed by ground and volume contributions has been proven suitable to describe the 3-D backscattering signatures of forest scenarios in a number of experiments. Under this hypothesis, the purpose of this letter is to investigate how synthetic aperture radar tomography (TomoSAR) can be used to estimate ground and volume polarimetric covariances and with which performance. An algorithm which is able to overcome the intrinsic ambiguity in the estimation problem is proposed, and it is shown to be a reliable alternative to the poorly performing full-rank Capon beamformer for estimating the ground polarimetric covariances. This performance improvement can be achieved, for instance, if an a priori knowledge of the ground topography (or an accurate estimate of it) is available. This analysis is carried out by processing an L-band TomoSAR stack acquired by the DLR’s E-SAR sensor over the temperate forest site of Traunstein.
Autors: Matteo Pardini;Konstantinos Papathanassiou;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1860 - 1864
Publisher: IEEE
 
» On the Evaluation of the 4-D Reaction Integral for the Scalar Potential in Galerkin’s Method of Moments
Abstract:
Despite the great progress made in the evaluation of the 4-D reaction integrals arising in the method of moments applied to the surface integral equation formulations, there are still some aspects that deserve to be explored further. The focus in this paper lies in the evaluation of the 4-D reaction integral for the scalar potential. We demonstrate that, unless this integral is computed to machine precision in the whole impedance matrix, it is imperative to maintain the trianglewise balance in the evaluation of the scalar potential part. A small imbalance, even at very small error, results in a loss of degrees of freedom (DOFs) for the charge distribution, violating the null-space property of the divergence operator and yielding potentially spurious solutions. The effect, although present, may go unnoticed at the conventional frequency regimes, where the usual mesh sizes can be applied. However, it becomes more pronounced as we approach the quasi-static limit, eventually rendering spurious solutions at the frequencies higher than the classical low-frequency breakdown would.
Autors: Diego Martínez Solís;Fernando Obelleiro Basteiro;Jose Manuel Taboada;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5356 - 5364
Publisher: IEEE
 
» On the Fundamental Limits of Random Non-Orthogonal Multiple Access in Cellular Massive IoT
Abstract:
Machine-to-machine (M2M) constitutes the communication paradigm at the basis of Internet of Things vision. M2M solutions allow billions of multi-role devices to communicate with each other or with the underlying data transport infrastructure without, or with minimal, human intervention. Current solutions for wireless transmissions originally designed for human-based applications thus require a substantial shift to cope with the capacity issues in managing a huge amount of M2M devices. In this paper, we consider the multiple access techniques as promising solutions to support a large number of devices in cellular systems with limited radio resources. We focus on non-orthogonal multiple access (NOMA) where, with the aim to increase the channel efficiency, the devices share the same radio resources for their data transmission. This has been shown to provide optimal throughput from an information theoretic point of view. We consider a realistic system model and characterize the system performance in terms of throughput and energy efficiency in an NOMA scenario with a random packet arrival model, where we also derive the stability condition for the system to guarantee the performance.
Autors: Mahyar Shirvanimoghaddam;Massimo Condoluci;Mischa Dohler;Sarah J. Johnson;
Appeared in: IEEE Journal on Selected Areas in Communications
Publication date: Oct 2017, volume: 35, issue:10, pages: 2238 - 2252
Publisher: IEEE
 
» On the Generation of Nondiffracting Beams in Extremely Subwavelength Applications
Abstract:
In this paper, extremely subwavelength evanescent Bessel beam launchers are designed, simulated, and experimentally tested to generate nondiffracting beams. The launching apertures consist of several concentric coils strategically positioned to spatially filter the fields of a single actively fed radiating coil. The geometrical properties of each coil element of the aperture were obtained through a procedure based on the orthogonal matching pursuit algorithm in order to maximize the quality of the launched beam while minimizing manufacturing complexity. Two apertures with outer diameters of 64 and 48 mm were fabricated and the generated field distributions were measured at the operating frequencies of 13.66 and 13.86 MHz, respectively. Desired and measured field distributions exhibited correlations above 0.9 even as the distance from the aperture was increased, demonstrating the ability of the apertures to approximate the field distribution and harmonic content of a Bessel beam. This paper furthers the study and practical implementation of Bessel beams and other types of beams in extremely subwavelength applications such as focusing, wireless power transfer, magnetic stimulation, and microwave ablation.
Autors: Erik Saturnino Gámez Rodríguez;Manjunath Machnoor;Gianluca Lazzi;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5228 - 5237
Publisher: IEEE
 
» On the Latent Variable Interpretation in Sum-Product Networks
Abstract:
One of the central themes in Sum-Product networks (SPNs) is the interpretation of sum nodes as marginalized latent variables (LVs). This interpretation yields an increased syntactic or semantic structure, allows the application of the EM algorithm and to efficiently perform MPE inference. In literature, the LV interpretation was justified by explicitly introducing the indicator variables corresponding to the LVs’ states. However, as pointed out in this paper, this approach is in conflict with the completeness condition in SPNs and does not fully specify the probabilistic model. We propose a remedy for this problem by modifying the original approach for introducing the LVs, which we call SPN augmentation. We discuss conditional independencies in augmented SPNs, formally establish the probabilistic interpretation of the sum-weights and give an interpretation of augmented SPNs as Bayesian networks. Based on these results, we find a sound derivation of the EM algorithm for SPNs. Furthermore, the Viterbi-style algorithm for MPE proposed in literature was never proven to be correct. We show that this is indeed a correct algorithm, when applied to selective SPNs, and in particular when applied to augmented SPNs. Our theoretical results are confirmed in experiments on synthetic data and 103 real-world datasets.
Autors: Robert Peharz;Robert Gens;Franz Pernkopf;Pedro Domingos;
Appeared in: IEEE Transactions on Pattern Analysis and Machine Intelligence
Publication date: Oct 2017, volume: 39, issue:10, pages: 2030 - 2044
Publisher: IEEE
 
» On the m-CAP Performance with Different Pulse Shaping Filters Parameters for Visible Light Communications
Abstract:
In pulse shaping filters, parameters such as the roll-off factor and the symbol span, which determine the overall performance, are of great importance when implementing a real-time system due to limited hardware resources. In this paper, we experimentally investigate a multiband carrier-less amplitude and phase (m-CAP) visible light communications (VLC) system employing such filters and assess the link performance for a range of filter lengths and show the relationship between the system data rate (or spectral efficiency) and computational complexity. We show that lower order m-CAP can offer the same system performance as higher order systems while offering much lower computational complexity. By optimizing the filter parameters and the order m of an m-CAP VLC link, we achieve the largest improvement in the data rate and bandwidth efficiency of 9.69% and 40.43%, respectively, when compared with 2- and 8-CAP. We also show that the m-CAP VLC link with can be designed with the same filter parameters to demonstrate a link with both the highest data rate and spectral efficiency simultaneously in contrast to lower order systems.
Autors: Petr Chvojka;Khald Werfli;Stanislav Zvanovec;Paul Anthony Haigh;Vaclav Hubata Vacek;Petr Dvorak;Petr Pesek;Zabih Ghassemlooy;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 12
Publisher: IEEE
 
» On the Oblivious Transfer Capacity of Generalized Erasure Channels Against Malicious Adversaries: The Case of Low Erasure Probability
Abstract:
Noisy channels are a powerful resource for cryptography as they can be used to obtain information-theoretic secure key agreement, commitment, and oblivious transfer protocols, among others. Oblivious transfer (OT) is a fundamental primitive, since it is complete for secure multi-party computation, and the OT capacity characterizes how efficiently a channel can be used for obtaining string oblivious transfer. Ahlswede and Csiszár (ISIT’07) presented upper and lower bounds on the OT capacity of generalized erasure channels (GECs) against passive adversaries. In the case of GEC with erasure probability at least 1/2, the upper and lower bounds match and, therefore, the OT capacity was determined. It was later proved by Pinto et al. [IEEE Trans. Inf. Theory 57(8)] that the OT capacity is identical for passive and malicious adversaries. In the case of GEC with erasure probability smaller than 1/2, the known lower bound against passive adversaries that was established by Ahlswede and Csiszár does not match their upper bound and it was unknown whether this OT rate could be achieved against malicious adversaries as well. In this paper, we show that there is a protocol against malicious adversaries achieving the same OT rate that was obtained against passive adversaries. We obtain our results by a new combination of interactive hashing and typicality tests that are suitable for dealing with the case of low erasure probability ().
Autors: Rafael Dowsley;Anderson C. A. Nascimento;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6819 - 6826
Publisher: IEEE
 
» On the Performance of Full-Duplex Multi-Relay Channels With DF Relays
Abstract:
In this paper, we consider a two-hop full-duplex multi-relay channel (FD-MRC) for exploiting the high spectral efficiency of FD systems and the diversity gains of multi-relay systems. Employing a decode-and-forward (DF) relaying protocol, the single best relay is selected from those relays that have successfully decoded the source message, which then helps forward the source message to the destination. Meanwhile, a new message is broadcast by the source, and all the relays, including the selected best one, attempt to decode this new message. In view of the effect of both inter-relay interference and self-interference, a one-step correlation exists between the relay decoding results in successive time slots. Then, a Markov chain-based analytical model is utilized for analyzing the exact outage probability of FD-MRC. Furthermore, a close-to-full diversity order of is analytically proved to be attainable for FD-MRC, where is a factor characterizing the efficiency of SI mitigation.
Autors: Qiang Li;Shangjie Feng;Xiaohu Ge;Guoqiang Mao;Lajos Hanzo;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9550 - 9554
Publisher: IEEE
 
» On the Performance of Visible Light Communication Systems With Non-Orthogonal Multiple Access
Abstract:
Visible light communication (VLC) has been proposed as a promising and efficient solution to indoor ubiquitous broadband connectivity. In this paper, non-orthogonal multiple access, which has been recently introduced as an effective scheme for fifth generation (5G) wireless networks, is considered in the context of VLC systems under different channel uncertainty models. To this end, we first derive a novel closed-form expression for the bit-error-rate (BER) under perfect channel state information (CSI). Capitalizing on this, we then quantify the effect of noisy and outdated CSI by deriving a simple and accurate approximation for the former and a tight upper bound for the latter. The offered results are corroborated by respective results from extensive Monte Carlo simulations and assist in developing useful insights on the effect of imperfect CSI knowledge on the overall system performance. Furthermore, it was shown that while noisy CSI leads to slight degradation in the BER performance, outdated CSI can cause considerable performance degradation, if the order of the users’ channel gains change due to the involved mobility.
Autors: Hanaa Marshoud;Paschalis C. Sofotasios;Sami Muhaidat;George K. Karagiannidis;Bayan S. Sharif;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6350 - 6364
Publisher: IEEE
 
» On the Practical Design of a High Power Density SiC Single-Phase Uninterrupted Power Supply System
Abstract:
This paper proposes a high power density SiC single-phase system potential for uninterrupted power supply applications. To get the high power density, the semiconductors, packaging, circuit topology, and thermal design are synthetically considered. To increase the switching frequency and reduce the size of the passive components, the SiC MOSFETs and diodes are chosen; to minimize the parasitic inductances and eliminate the snubbers, the SiC bare dies are packaged as the half-bridge (HB) modules; to remove the bulky dc-link capacitors, the full-bridge inverter and the active power filter are designed, and they are structured by using the fabricated SiC HB modules; and finally to dissipate the heat from such a compact enclosure in the cost-efficient way, the heat sink of the modules and the forced air cool system are well designed, and the thermal 3-D finite-element analysis model is built to survey the best cooling configuration. A 2-kVA prototype is built and tested, and the power density of the system is up to 58 W/in3 and the maximal efficiency is up to 98.3%.
Autors: Cai Chen;Yu Chen;Yifan Tan;Jianming Fang;Fang Luo;Yong Kang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2704 - 2716
Publisher: IEEE
 
» On the Solution Set of the Admissible Bounded Control Problem via Orthogonal Polynomials
Abstract:
The complete set of solutions to the admissible bounded control problem of the Brunovsky control system of dimension for via orthogonal polynomials on and their second kind polynomials is obtained. For given an initial position and a time greater than the optimal time , we prove that there are only two bang-bang controls with switchings that steer the state trajectory to the origin exactly at time .
Autors: Abdon E. Choque-Rivero;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5213 - 5219
Publisher: IEEE
 
» On the Stability Margin of Networked Dynamical Systems
Abstract:
This paper is concerned with the stability (gain and phase) margin of networked dynamical systems, e.g., vehicles in formation, each of which has access to the state of its neighbors and subsequently uses a state feedback gain for a certain global objective such as attitude synchronization. Here, the network topology is directed and described by a generalized Laplacian matrix . An individual dynamical system can adopt its own state feedback control law such as a linear-quadratic-regulator controller for an ample stability margin, but it may lose the stability margin to a great extent when the same control strategy utilizing relative state information is used after being interconnected with other dynamical systems. This paper reveals and elaborates upon the following four facts: First, the stability margin after interconnection is quantified via the minimum singular value of a frequency-dependent matrix made up of and ; Second, the stability margin of a networked dynamical system having a pole at the origin is at most the inverse of the zero-eigenvalue sensitivity of ; Third, there exists an upper bound of the stability margin that has a computational merit, and asymptotically converges to the exact margin with respect to network size, probability of link existence, and control gain in a random network setting; and finally, can be designed to maximize the stability margin. Numerical examples are provided to demonstrate the elaboration.
Autors: Yoonsoo Kim;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5451 - 5456
Publisher: IEEE
 
» On the Sum-Rate Capacity of Poisson MISO Multiple Access Channels
Abstract:
In this paper, we analyze the sum-rate capacity of two-user Poisson multiple access channels (MAC), when the receiver is equipped with single antenna. We first characterize the sum-rate capacity of the non-symmetric Poisson MAC when each transmitter has a single antenna. While the sum-rate capacity of the symmetric Poisson MAC with single antenna at each transmitter has been characterized in the literature, the special property exploited in the existing method for the symmetric case does not hold for the non-symmetric channel anymore. We obtain the optimal input that achieves the sum-rate capacity by solving a non-convex optimization problem. We show that, for certain channel parameters, it is optimal for a single user to transmit to achieve the sum-rate capacity. This is in sharp contrast to the Gaussian MAC, in which both users must transmit, either simultaneously or at different times, in order to achieve the sum-rate capacity. We then characterize the sum-rate capacity of the Poisson multiple-input single-output (MISO) MAC with multiple antennas at each transmitter and single antenna at the receiver. By converting a non-convex optimization problem with a large number of variables into a non-convex optimization problem with two variables, we show that the sum-rate capacity of the Poisson MISO MAC with multiple transmit antennas is equivalent to a properly constructed Poisson MAC with a single antenna at each transmitter.
Autors: Ain-ul-Aisha;Lifeng Lai;Yingbin Liang;Shlomo Shamai Shitz;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6457 - 6473
Publisher: IEEE
 
» On the Validity of an Analytical Solution for Characterizing Backscattering From Tree Trunks for FOPEN Sensing at $P$ -Band
Abstract:
A comprehensive set of simulations is performed to analyze the accuracy of an analytical solution for characterizing the backscattering responses of circular cylindrical tree trunks located above a dielectric ground. The formulation of interest here is from the volumetric current integration method, combined with a ray-based approach for the treatment of ground effects. Through comparisons with a reference solution provided by a full-wave solver, the region of validity of the closed-form approximate solution as a function of trunk length, trunk radius, incidence angle, and polarization is derived. Trunks with and without tapering along their lengths are considered. It is noted that, in general, the error behavior of the vv solution exhibits more complexity than that of the hh solution, due to the Brewster angle effects of the trunk and the ground; consequently, the hh solution is valid over a wider range of length and radius values. The backscattering signatures of the trunks are also examined in the imaging domain. It is found that the analytical solution can correctly predict the single ground-bounce returns but may not consistently capture other less prominent effects, such as scattering from the top of the trunk and higher order interactions.
Autors: DaHan Liao;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5639 - 5644
Publisher: IEEE
 
» On Turing Instability in Nonhomogeneous Reaction-Diffusion CNN’s
Abstract:
Several results on instability in nonhomogeneous architectures able to generate Turing patterns are presented. The approach makes use of the continuity theorem regarding the dependence of polynomial roots on coefficients and of the root-locus techniques for small, and large parameter deviations from their homogeneous values, respectively. The results are valid for any linearized nonhomogeneous discrete model capable of generating Turing patterns.
Autors: Liviu Goras;Paul Ungureanu;Leon O. Chua;
Appeared in: IEEE Transactions on Circuits and Systems I: Regular Papers
Publication date: Oct 2017, volume: 64, issue:10, pages: 2748 - 2760
Publisher: IEEE
 
» On Using the Intelligent Edge for IoT Analytics
Abstract:
This article presents a flexible architecture for Internet of Things (IoT) data analytics using the concept of fog computing. The authors identify different actors and their roles in order to design adaptive IoT data analytics solutions. The presented approach can be used to effectively design robust IoT applications that require a tradeoff between cloud- and edge-based computing depending on dynamic application requirements. The potential use cases of this technology can be found in scenarios such as smart cities, security surveillance, and smart manufacturing, where the quality of user experience is important.
Autors: Pankesh Patel;Muhammad Intizar Ali;Amit Sheth;
Appeared in: IEEE Intelligent Systems
Publication date: Oct 2017, volume: 32, issue:5, pages: 64 - 69
Publisher: IEEE
 
» On-Chip ESD Protection Device for High-Speed I/O Applications in CMOS Technology
Abstract:
The diode operated under forward-biased condition has been widely used as an on-chip electrostatic discharge (ESD) protection device for high-speed circuits to sustain high ESD robustness, but the parasitic capacitance of diode may bring a negative impact to the circuits operating at higher speed. The ESD protection design with low parasitic capacitance has been strongly requested in high-speed I/O applications. The traditional methods to reduce parasitic capacitance were using a stacked diode or a stacked diode with embedded silicon-controlled rectifier (SCR). The stacked diode or the stacked diode with embedded SCR would have larger turn-on resistance to cause a higher clamping voltage. It should be further improved to achieve good ESD protection effectiveness for the high-speed I/O applications. In this paper, a new ESD protection device with reduced parasitic capacitance and smaller turn-on resistance to improve ESD protection effectiveness is proposed. The measurement results from the silicon chip have demonstrated that the proposed ESD device can achieve smaller parasitic capacitance, lower turn-on resistance, and higher ESD robustness, compared with the conventional devices. The proposed ESD protection device is very suitable to protect the high-speed I/O circuits in nanoscale CMOS technology.
Autors: Jie-Ting Chen;Chun-Yu Lin;Ming-Dou Ker;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 3979 - 3985
Publisher: IEEE
 
» On-Demand Disassembly of Paramagnetic Nanoparticle Chains for Microrobotic Cargo Delivery
Abstract:
Paramagnetic nanoparticles are considered as attractive building blocks, particularly for robotic delivery of drugs. Although paramagnetic nanoparticles can be effectively gathered and transported using external magnetic fields, the disassembly process is yet to be fully investigated to avoid the formation of aggregations. In this paper, we report a novel method of controllable disassembly of paramagnetic nanoparticle chains using a predefined dynamic magnetic field. The dynamic field is capable of performing spreading and fragmentation of the particle chains simultaneously. Using the magnetic dipole–dipole repulsive forces, the final area covered by the particle chains swells up to 545% of the initial area. The final length distribution presents a strong relationship with the frequency of the dynamic field in deionized (DI) water and two kinds of biofluids. An analytical model of phase lag is proposed, which shows good agreement with the experimental results. Furthermore, we also present an assembly process using a rotating magnetic field, indicating that the assembly disassembly process is reversible. In addition, batch-cargo delivery of polystyrene microbeads using the nanoparticle chains as swarm-like nanorobots is demonstrated.
Autors: Jiangfan Yu;Tiantian Xu;Zheyu Lu;Chi Ian Vong;Li Zhang;
Appeared in: IEEE Transactions on Robotics
Publication date: Oct 2017, volume: 33, issue:5, pages: 1213 - 1225
Publisher: IEEE
 
» Online Combination of EPID & Cherenkov Imaging for 3-D Dosimetry in a Liquid Phantom
Abstract:
Online acquisition of Cherenkov and portal imaging data was combined with a reconstruction scheme called EC3-D, providing a full 3-D dosimetry of megavoltage X-ray beams in a water tank. The methodology was demonstrated and quantified in a single static beam. Furthermore, the dynamics and visualization of the 3-D dose reconstruction were demonstrated with a volumetric modulated arc therapy plan for TG-119 C-Shape geometry. The developed algorithm combines depth dose information, provided by Cherenkov images, with the lateral dose distribution, provided by the electronic portal imaging device. The strength of our approach lies in the acquisition of both imaging data streams with sub-millimeter theoretical resolution at 5-Hz frame-rate, which can be concurrently processed by the fast Fourier transform-based analysis, thus providing means for an efficient real-time 3-D dosimetry.
Autors: Petr Bruza;Jacqueline M. Andreozzi;David J. Gladstone;Lesley A. Jarvis;Joerg Rottmann;Brian W. Pogue;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2099 - 2103
Publisher: IEEE
 
» Online Identification of Power System Equivalent Inertia Constant
Abstract:
This paper proposes a closed-loop identification method to estimate the equivalent inertia constant of a power system at the connection bus. A microperturbation is first performed with a well-designed multisine signal probed through any power electronic devices in the internal system. Then, responses of frequency and active power measured by the phase measurement unit at the connection bus are used for the closed-loop identification. Compared to the conventional transient signal based method, the proposed method has simple implementation and minimum impacts on the system security, and thus could be carried out in real-time to identify the time-varying and nonlinear equivalent inertia constant in modern power systems with complex heterogeneous components. The effectiveness of the proposed method is validated in an 8-generator 36-bus simulation system and an actual power system.
Autors: Junbo Zhang;Hanchen Xu;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8098 - 8107
Publisher: IEEE
 
» Online Monitoring and Diagnosis of HV Cable Faults by Sheath System Currents
Abstract:
Cross-bonded metal sheath connection is applied in sectioned single-core power cables to reduce or eliminate the voltages that are induced in the sheath over long distances. However, cross-bonded cables present an opportunity as well as a challenge for online measurement and diagnosis of cable conditions. In this paper, a methodology to identify cable sheath faults through analysis of the sheath system currents in a cross-bonded cable system is presented. First, a numerical model is established to simulate the sheath currents in cross-bonded cable systems. Second, analyses of several faults, which happen frequently with serious consequences, are presented on the basis of current measurement at the link cable. Simulations of normal and fault conditions are given to determine the feasibility of fault diagnosis. A case study using field data from a cable tunnel in China considering the normal condition is presented to verify the numerical model. Results in normal condition show good consistency with field data with error less than 5%. Simulation results of fault conditions show that analysis of readings from six current sensors can distinguish different fault types and fault positions using the method proposed. Based on the analyses, criteria are established for sheath loop fault type diagnosis.
Autors: Xiang Dong;Yang Yang;Chengke Zhou;Donald M. Hepburn;
Appeared in: IEEE Transactions on Power Delivery
Publication date: Oct 2017, volume: 32, issue:5, pages: 2281 - 2290
Publisher: IEEE
 
» Online Optimization of Interference Coordination Parameters in Small Cell Networks
Abstract:
This paper focuses on interference coordination between the small cell and macro cell tiers of a wireless access network. We present a self-optimization mechanism for LTE-A eICIC parameters (CRE bias and ABS ratio) following a novel approach based on a model-free learning strategy, not requiring any previous knowledge about the network (e.g., topology, interference graph, and scheduling algorithms). Our proposal is built upon a stochastic optimization algorithm known as response surface methodology (RSM), that we use to find efficient eICIC configurations during network operation (online learning), adapting to changing network conditions, such as traffic or user distribution. The objective consists of optimizing a performance metric for which, in general, mathematical expression is unavailable. In particular, we consider the fifth percentile throughput defined by the 3GPP. By means of RSM, our mechanism obtains local approximations of the objective function to perform steepest ascent iterations with an adjustable level of statistical accuracy. The algorithm can be extended to account for stochastic constraints, allowing the network to optimize one performance metric while maintaining other metrics above a desired level.
Autors: Jose A. Ayala-Romero;Juan J. Alcaraz;Javier Vales-Alonso;Esteban Egea-López;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6635 - 6647
Publisher: IEEE
 
» Online QoS Prediction for Runtime Service Adaptation via Adaptive Matrix Factorization
Abstract:
Cloud applications built on service-oriented architectures generally integrate a number of component services to fulfill certain application logic. The changing cloud environment highlights the need for these applications to keep resilient against QoS variations of their component services so that end-to-end quality-of-service (QoS) can be guaranteed. Runtime service adaptation is a key technique to achieve this goal. To support timely and accurate adaptation decisions, effective and efficient QoS prediction is needed to obtain real-time QoS information of component services. However, current research has focused mostly on QoS prediction of working services that are being used by a cloud application, but little on predicting QoS values of candidate services that are equally important in determining optimal adaptation actions. In this paper, we propose an adaptive matrix factorization (namely AMF) approach to perform online QoS prediction for candidate services. AMF is inspired from the widely-used collaborative filtering techniques in recommender systems, but significantly extends the conventional matrix factorization model with new techniques of data transformation, online learning, and adaptive weights. Comprehensive experiments, as well as a case study, have been conducted based on a real-world QoS dataset of Web services (with over 40 million QoS records). The evaluation results demonstrate AMF’s superiority in achieving accuracy, efficiency, and robustness, which are essential to enable optimal runtime service adaptation.
Autors: Jieming Zhu;Pinjia He;Zibin Zheng;Michael R. Lyu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2911 - 2924
Publisher: IEEE
 
» Online-Learning-Based Mode Prediction Method for Quality Scalable Extension of the High Efficiency Video Coding (HEVC) Standard
Abstract:
SHVC, the scalable extension of High Efficiency Video Coding (HEVC), uses advanced inter-layer prediction features in addition to the advanced compression tools of HEVC to improve the compression performance. Using combined features has brought us improved compression performance at the cost of huge computational complexity for the SHVC encoder. This complexity is mainly because of the the inter/intra-prediction mode search of the coding units. The focus of this study is on developing an efficient complexity reduction for quality scalability of SHVC encoder, with the intention to facilitate the adoption of SHVC for real-time applications. In this regard, first, we build a probabilistic model that uses the mode information and motion homogeneity of already encoded blocks in the enhancement layer (EL) and the base layer to predict the probabilities of all the available inter/intra modes of the to-be-coded block in the EL. Then, we propose an online-learning-based fast mode, assigning (FMA) method that uses the proposed probabilistic model to predict the mode of the to-be-coded block in the EL. Performance evaluation shows that our proposed FMA method reduces the total execution time of the SHVC encoder by 45.40% on average compared with unmodified SHVC codec while maintaining the overall video quality.
Autors: Hamid Reza Tohidypour;Hossein Bashashati;Mahsa T. Pourazad;Panos Nasiopoulos;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Oct 2017, volume: 27, issue:10, pages: 2204 - 2215
Publisher: IEEE
 
» Onto a Skewness Approach to the Generalized Curvature Ocean Surface Scattering Model
Abstract:
The generalized curvature ocean surface scattering model [general curvature model (GCM)] is extended and revisited. Two key steps are addressed in this paper, namely, a necessary sea surface spectrum undressing procedure and the inclusion of a skewness phase-related component. Normalized radar cross-section (NRCS) simulations are generated at C-band for various wind conditions, polarizations, and incidence angles. Results are compared with CMOD5.n. Although the sea surface spectrum undressing procedure is a necessary step, the overall NRCS dynamic is notably affected only in low wind conditions (≤5 m/s). The inclusion of the skewness phase-related component makes the most impact to the NRCS dynamic where the upwind/downwind asymmetry is clearly detectable. A good agreement between the upwind/downwind asymmetry of the extended GCM and CMOD5.n is achieved for moderate winds (≈5–10 m/s) and moderate incidence angles (≈32°–40°). For low incidence angles (<26°), the GCM tends to overestimate the upwind/downwind asymmetry compared with CMOD5.n.
Autors: Faozi Saïd;Harald Johnsen;Frédéric Nouguier;Bertrand Chapron;Geir Engen;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5843 - 5853
Publisher: IEEE
 
» Open Access Dataset for EEG+NIRS Single-Trial Classification
Abstract:
We provide an open access dataset for hybrid brain–computer interfaces (BCIs) using electroencephalography (EEG) and near-infrared spectroscopy (NIRS). For this, we conducted two BCI experiments (left versus right hand motor imagery; mental arithmetic versus resting state). The dataset was validated using baseline signal analysis methods, with which classification performance was evaluated for each modality and a combination of both modalities. As already shown in previous literature, the capability of discriminating different mental states can be enhanced by using a hybrid approach, when comparing to single modality analyses. This makes the provided data highly suitable for hybrid BCI investigations. Since our open access dataset also comprises motion artifacts and physiological data, we expect that it can be used in a wide range of future validation approaches in multimodal BCI research.
Autors: Jaeyoung Shin;Alexander von Lühmann;Benjamin Blankertz;Do-Won Kim;Jichai Jeong;Han-Jeong Hwang;Klaus-Robert Müller;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Oct 2017, volume: 25, issue:10, pages: 1735 - 1745
Publisher: IEEE
 
» Opportunistic Channel Sharing in Stochastic Networks With Dynamic Traffic
Abstract:
In this paper, we consider the stochastic network with dynamic traffic. The spatial distribution of access points (APs) and users are modeled as mutually independent Poisson point processes. Different from most of the previous literature works, which assume that all the APs are fully loaded, we consider the fact that APs having no data to transmit do not generate interference to users. The APs opportunistically share the channel according to the existence of the packet to be transmitted and the proposed interference suppression strategy. In the interference suppression region, only one AP can be active at a time to transmit the packet on the channel and the other adjacent APs keep silent to reduce serious interference. The idle probability of any AP, influenced by the traffic load and availability of the channels, is analyzed. The density of simultaneously active APs in the network is obtained, and the packet loss rate is further elaborated. We reveal the impacts of network features (e.g., AP density, user density, and channel state) and service features (e.g., user request and packet size) on the network performance.
Autors: Bin Xia;Yingbin Liu;Chenchen Yang;Zhiyong Chen;Weiliang Xie;Yong Zhao;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9587 - 9591
Publisher: IEEE
 
» Opportunities for Energy Storage: Assessing Whole-System Economic Benefits of Energy Storage in Future Electricity Systems
Abstract:
Any Cost-effective transition toward low-carbon electricity supply will necessitate improved system flexibility to address the challenges of increased balancing requirements and degradation in asset use. Energy storage (ES) represents a flexible option that can bring significant, fundamental economic benefits to various areas in the electric power sector, including reduced investment requirements for generation, transmission, and distribution infrastructure as well as reduced system operation and balancing costs. The additional flexibility offered by ES could also significantly reduce the requirement for investment in low-carbon generation capacity while achieving the established carbon intensity targets. Moreover, ES may present significant option value, as it can provide flexibility for dealing with uncertainty in future system development.
Autors: Goran Strbac;Marko Aunedi;Ioannis Konstantelos;Roberto Moreira;Fei Teng;Rodrigo Moreno;Danny Pudjianto;Adriana Laguna;Panagiotis Papadopoulos;
Appeared in: IEEE Power and Energy Magazine
Publication date: Oct 2017, volume: 15, issue:5, pages: 32 - 41
Publisher: IEEE
 
» Optical Frequency Comb Generation Based on Dual-Polarization IQ Modulator Shared by Two Polarization-Orthogonal Recirculating Frequency Shifting Loops
Abstract:
A novel optical frequency comb generator (OFCG) based on a dual-polarization IQ modulator shared by two polarization-orthogonal recirculating frequency shifting (RFS) loops has been proposed. The states of polarization of two optical subcombs output from the respective loops are kept orthogonal in the proposed scheme. More than 80 carriers, whose carrier-to-noise ratio (CNR) can be further improved with better conditions, have been demonstrated experimentally. Meanwhile, the number and frequency spacing of the carriers of both the two optical subcombs can be easily tuned due to the unique feature of flexible controls, which is different from the previous dual-RFS-loop-based OFCG in which the carrier frequency spacing must be kept fixed. Based on the theoretical and experimental results, the proposed scheme has the advantages of good feasibility, tunability, and flexibility, which can find the potential applications in various fields.
Autors: Jianping Li;Huatao Ma;Zhaohui Li;Xiaoguang Zhang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Optical Power Monitoring with Ultrahigh Sensitivity in Silicon Waveguides and Ring Resonators
Abstract:
We demonstrate optical power monitoring using a silicon resistor enabled by the surface and defect states-induced photoconductance effect. Ultrahigh optical power detection sensitivity of −40 dBm under a low AC drive voltage of 5 mV is obtained with the facilitation of a lock-in amplifier circuitry. The detection scheme is applied to monitor the resonances in single and coupled-ring resonators. Intracavity resonance spectrum is successfully measured at both the static and the thermal tuning conditions. The demonstration opens a compelling new way for nonintrusive on-chip optical power detection by exploiting doped silicon resistor-based thermooptic heaters.
Autors: Dong Li;Linjie Zhou;Liangjun Lu;Jianping Chen;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 10
Publisher: IEEE
 
» Optical–Optical Synchronization Between Two Independent Femtosecond Yb-Fiber Lasers With 10 –20 Instability in 105 s
Abstract:
Optical–optical synchronization between independent mode-locked lasers with attosecond timing precision is essential for arbitrary electric-field waveform generation, subcycle optical pulse synthesis, optical frequency transfer as well as next-generation photon-science facilities, e.g., X-ray free-electron lasers. Long-term stable operation with low timing drift is highly desired for all above applications. Here, we present a five-day uninterrupted timing synchronization between two independent femtosecond Yb-fiber lasers via balanced optical correlation method. The out-of-loop residual timing drift over the entire time frame reaches 733 as rms, corresponding to instability at . To the best of our knowledge, it is the first characterization of 105 s instability for subfemtosecond optical–optical synchronization based on mode-locked lasers.
Autors: Haochen Tian;Youjian Song;Jiahe Yu;Haosen Shi;Minglie Hu;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 7
Publisher: IEEE
 
» Optically-Pumped Single-Mode Deep-Ultraviolet Microdisk Lasers With AlGaN-Based Multiple Quantum Wells on Si Substrate
Abstract:
In this work, we report demonstration of optically-pumped single-mode deep-ultraviolet lasing actions operating at room temperature from ∼1-μm 150-nm-thick undercut microdisks with AlN/Al0.35Ga 0.65N (5.5 nm/2.5 nm) multiple quantum wells. These AlGaN-based microdisks are grown on Si substrate by metal-organic chemical vapor deposition. The lasing wavelength centers at ∼300.1 nm with the linewidth of ∼1.0 nm as the excitation exceeds the lasing threshold of ∼24.2 mJ/cm2. An emission coupling factor (β) of 9.2 × 10−2 is estimated based on the light output characteristics of the AlN/AlGaN microdisks with increasing the pumping densities. Concurrently, a 100 meV blue-shift in the mode energy has also been observed. The lasing spectral peak is attributed to fundamental-order transverse-electric whispering-gallery modes, confirmed by three-dimensional finite-difference time-domain simulations.
Autors: Yiyun Zhang;Hongjian Li;Panpan Li;Arash Dehzangi;Liancheng Wang;Xiaoyan Yi;Guohong Wang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Optimal Aircraft Planar Navigation in Static Threat Environments
Abstract:
We consider the problem of navigating a military aircraft in a threat environment to its final destination while minimizing the maximum threat level and the length of the aircraft path. The proposed method to construct optimal low-risk aircraft paths involves a simple geometric procedure and is very computationally efficient. The effectiveness of the developed algorithm is illustrated by a number of examples and comparisons with a fuzzy logic based algorithm.
Autors: Andrey V. Savkin;Hailong Huang;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2413 - 2426
Publisher: IEEE
 
» Optimal Beamforming for Gaussian MIMO Wiretap Channels With Two Transmit Antennas
Abstract:
A Gaussian multiple-input multiple-output wiretap channel in which the eavesdropper and legitimate receiver are equipped with arbitrary numbers of antennas and the transmitter has two antennas is studied in this paper. The input covariance matrix that achieves the secrecy capacity is determined. In particular, it is shown that the secrecy capacity of this channel can be achieved by linear precoding. Precoding and power allocation schemes that maximize the achievable secrecy rate, and thus achieve the secrecy capacity, are developed. The secrecy capacity is then compared with the achievable secrecy rate of generalized singular value decomposition (GSVD)-based precoding, which is the best previously proposed technique for this problem. Numerical results demonstrate that substantial gain can be obtained in secrecy rate between the proposed and GSVD-based precodings.
Autors: Mojtaba Vaezi;Wonjae Shin;H. Vincent Poor;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6726 - 6735
Publisher: IEEE
 

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