Electrical and Electronics Engineering publications abstract of: 10-2017 sorted by title, page: 18

» Reliable Video Streaming With Strict Playout Deadline in Multihop Wireless Networks
Abstract:
Motivated by emerging vision-based intelligent services, we consider the problem of rate adaptation for high-quality and low-delay visual information delivery over wireless networks using scalable video coding. Rate adaptation in this setting is inherently challenging due to the interplay between the variability of the wireless channels, the queuing at the network nodes, and the frame-based decoding and playback of the video content at the receiver at very short time scales. To address the problem, we propose a low-complexity model-based rate adaptation algorithm for scalable video streaming systems, building on a novel performance model based on stochastic network calculus. We validate the analytic model using extensive simulations. We show that it allows fast near-optimal rate adaptation for fixed transmission paths, as well as cross-layer optimized routing and video rate adaptation in mesh networks, with less than % quality degradation compared to the best achievable performance.
Autors: Hussein Al-Zubaidy;Viktoria Fodor;György Dán;Markus Flierl;
Appeared in: IEEE Transactions on Multimedia
Publication date: Oct 2017, volume: 19, issue:10, pages: 2238 - 2251
Publisher: IEEE
 
» Reliable Virtual Full-Duplex Relaying in the Presence of Interrelay Interference
Abstract:
Interrelay interference (IRI) is known to limit the performance of virtual full-duplex (VFD) relaying schemes. Available interference cancelation schemes are unable to simultaneously improve the diversity and maintain the multiplexing gain of VFD relaying schemes in multiple antennas scenarios. In this paper, we propose a technique to improve the reliability of multiantenna VFD relaying scheme, while maintaining the multiplexing gain in the presence of IRI. In the proposed scheme, the source and interrelay channels are concatenated and their signals are jointly decoded at the relay. A superposition of the decoded messages is forwarded to the destination. To reduce the effect of IRI on the receiving relay, two suboptimal relay transmit antenna selection schemes, namely, random antenna selection and maximum capacity antenna selection, are investigated. The system capacity and outage probability bounds of the proposed scheme are derived in closed form. The diversity and multiplexing tradeoff is also characterized. The analytical and numerical results show that the proposed scheme can achieve full diversity and maintain the multiplexing gain of the full-duplex relaying scheme. Also, the proposed scheme can outperform conventional VFD relaying scheme in terms of reliability even in the presence of IRI.
Autors: Igbafe Orikumhi;Chee Yen Leow;Yonghui Li;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9098 - 9109
Publisher: IEEE
 
» Reliable Virtual Machine Placement and Routing in Clouds
Abstract:
In current cloud computing systems, when leveraging virtualization technology, the customer’s requested data computing or storing service is accommodated by a set of communicated virtual machines (VM) in a scalable and elastic manner. These VMs are placed in one or more server nodes according to the node capacities or failure probabilities. The VM placement availability refers to the probability that at least one set of all customer’s requested VMs operates during the requested lifetime. In this paper, we first study the problem of placing at most groups of requested VMs on a minimum number of nodes, such that the VM placement availability is no less than , and that the specified communication delay and connection availability for each VM pair under the same placement group are not violated. We consider this problem with and without Shared-Risk Node Group (SRNG) failures, and prove this problem is NP-hard in both cases. We subsequently propose an exact Integer Nonlinear Program (INLP) and an efficient heuristic to solve this problem. We conduct simulations to compare the proposed algorithms with two existing heuristics in terms of performance. Finally, we study the related reliable routing problem of establishing a connection over at most link-disjoint paths from a source to a destination, such that the co- nection availability requirement is satisfied and each path delay is no more than a given value. We devise an exact algorithm and two heuristics to solve this NP-hard problem, and evaluate them via simulations.
Autors: Song Yang;Philipp Wieder;Ramin Yahyapour;Stojan Trajanovski;Xiaoming Fu;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2965 - 2978
Publisher: IEEE
 
» Remote Sensing Image Registration Based on Multifeature and Region Division
Abstract:
Although many feature-based registration methods have been proposed, automatic image registration is still a challenging task due to the influence of various conditions and uncertain difficulties for remote sensing images. In this letter, a novel image registration method, including two types of feature detectors and a region boundary constraint strategy for matching, is proposed. Two types of features detected by scale-invariant feature transform and Harris operators have advantages of keeping different structural information in the image and increasing the number of keypoints for later matching. Afterward, a region boundary constraint strategy based on the image sketch map is utilized in matching step. This strategy restricts the detected two types of features in their respective structural region and nonstructural region to reduce the incorrect correspondences. Experimental results demonstrate the superiority of our proposed registration algorithm compared with other research works in terms of correct matching number and aligning accuracy.
Autors: Wenping Ma;Yue Wu;Yafei Zheng;Zelian Wen;Liang Liu;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1680 - 1684
Publisher: IEEE
 
» Remote Sensing Image Scene Classification Using Bag of Convolutional Features
Abstract:
More recently, remote sensing image classification has been moving from pixel-level interpretation to scene-level semantic understanding, which aims to label each scene image with a specific semantic class. While significant efforts have been made in developing various methods for remote sensing image scene classification, most of them rely on handcrafted features. In this letter, we propose a novel feature representation method for scene classification, named bag of convolutional features (BoCF). Different from the traditional bag of visual words-based methods in which the visual words are usually obtained by using handcrafted feature descriptors, the proposed BoCF generates visual words from deep convolutional features using off-the-shelf convolutional neural networks. Extensive evaluations on a publicly available remote sensing image scene classification benchmark and comparison with the state-of-the-art methods demonstrate the effectiveness of the proposed BoCF method for remote sensing image scene classification.
Autors: Gong Cheng;Zhenpeng Li;Xiwen Yao;Lei Guo;Zhongliang Wei;
Appeared in: IEEE Geoscience and Remote Sensing Letters
Publication date: Oct 2017, volume: 14, issue:10, pages: 1735 - 1739
Publisher: IEEE
 
» Remote Sensing Image Scene Classification: Benchmark and State of the Art
Abstract:
Remote sensing image scene classification plays an important role in a wide range of applications and hence has been receiving remarkable attention. During the past years, significant efforts have been made to develop various data sets or present a variety of approaches for scene classification from remote sensing images. However, a systematic review of the literature concerning data sets and methods for scene classification is still lacking. In addition, almost all existing data sets have a number of limitations, including the small scale of scene classes and the image numbers, the lack of image variations and diversity, and the saturation of accuracy. These limitations severely limit the development of new approaches especially deep learning-based methods. This paper first provides a comprehensive review of the recent progress. Then, we propose a large-scale data set, termed “NWPU-RESISC45,” which is a publicly available benchmark for REmote Sensing Image Scene Classification (RESISC), created by Northwestern Polytechnical University (NWPU). This data set contains 31 500 images, covering 45 scene classes with 700 images in each class. The proposed NWPU-RESISC45 1) is large-scale on the scene classes and the total image number; 2) holds big variations in translation, spatial resolution, viewpoint, object pose, illumination, background, and occlusion; and 3) has high within-class diversity and between-class similarity. The creation of this data set will enable the community to develop and evaluate various data-driven algorithms. Finally, several representative methods are evaluated using the proposed data set, and the results are reported as a useful baseline for future research.
Autors: Gong Cheng;Junwei Han;Xiaoqiang Lu;
Appeared in: Proceedings of the IEEE
Publication date: Oct 2017, volume: 105, issue:10, pages: 1865 - 1883
Publisher: IEEE
 
» Renewable Energy Microgrids in Northern Remote Communities
Abstract:
If you consider community electricity access issues and their environmental impact, you might not think Canada would have communities where these are major concerns. Canada has abundant dispersed natural resources providing sufficient electrical capacity with a relatively low environmental footprint. In general terms, the country has enough generation capacity to supply electricity for the vast majority of the population and for foreseeable growth. In addition, since 2002, Canada has reduced its environmental footprint from the electricity sector, mainly due to the retirement of coal plants. So, what is the problem?
Autors: Mariano Arriaga;Ehsan Nasr;Hayley Rutherford;
Appeared in: IEEE Potentials
Publication date: Oct 2017, volume: 36, issue:5, pages: 22 - 29
Publisher: IEEE
 
» RepCloud: Attesting to Cloud Service Dependency
Abstract:
Security enhancements to the emerging IaaS (Infrastructure as a Service) cloud computing systems have become the focus of much research, but little of this targets the underlying infrastructure. Trusted cloud systems are proposed to integrate trusted computing infrastructure with cloud systems. With remote attestations, cloud customers are able to determine the genuine behaviors of their applications’ hosts; and therefore they establish trust to the cloud. However, the current trusted clouds have difficulties in effectively attesting to the cloud service dependency for customers’ applications, due to the cloud’s complexity, heterogeneity and dynamism. In this paper, we present RepCloud, a decentralized cloud trust management framework, inspired by the reputation systems from the research in peer-to-peer systems. With RepCloud, cloud customers are able to determine the properties of the exact nodes that may affect the genuine functionalities of their applications, without obtaining much internal information of the cloud. Experiments showed that besides achieving fine-grained cloud service dependency attestation, RepCloud incurred lower trust management overhead than the existing trusted cloud systems.
Autors: Anbang Ruan;Andrew Martin;
Appeared in: IEEE Transactions on Services Computing
Publication date: Oct 2017, volume: 10, issue:5, pages: 675 - 688
Publisher: IEEE
 
» Repeatable Motion Planning for Redundant Robots Over Cyclic Tasks
Abstract:
We consider the problem of repeatable motion planning for redundant robotic systems performing cyclic tasks in the presence of obstacles. For this open problem, we present a control-based randomized planner, which produces closed collision-free paths in configuration space and guarantees continuous satisfaction of the task constraints. The proposed algorithm, which relies on bidirectional search and loop closure in the task-constrained configuration space, is shown to be probabilistically complete. A modified version of the planner is also devised for the case in which configuration-space paths are required to be smooth. Finally, we present planning results in various scenarios involving both free-flying and nonholonomic robots to show the effectiveness of the proposed method.
Autors: Giuseppe Oriolo;Massimo Cefalo;Marilena Vendittelli;
Appeared in: IEEE Transactions on Robotics
Publication date: Oct 2017, volume: 33, issue:5, pages: 1170 - 1183
Publisher: IEEE
 
» Replication-Based Outer Bounds: On the Optimality of “Half the Cake” for Rank-Deficient MIMO Interference Networks
Abstract:
In order to gain new insights into multiple-input–multiple-output (MIMO) interference networks, the optimality of (half the cake per user) degrees of freedom is explored for a -user MIMO interference channel where the cross-channels have arbitrary rank constraints, and the th transmitter and receiver are equipped with antennas each. The result consolidates and significantly generalizes results from prior studies by Krishnamurthy et al., of rank-deficient interference channels where all users have antennas; and by Tang et al., of full rank interference channels where the th user pair has antennas. The broader outcome of this paper is a novel class of replication-based outer bounds for arbitrary rank-constrained MIMO interference networks where replicas of existing users are added as auxiliary users and the network connectivity is chosen to ensure that any achievable scheme for the original network also works in the new network. The replicated network creates a new perspective of the problem, so that even simple arguments such as user cooperation become quite powerful when applied in the replicated network, giving rise to stronger outer bounds, than when applied directly in the original network. Remarkably, the replication-based bounds are broadly applicable not only to MIMO interference channels with arbitrary rank-constraints, but much more broadly, even beyond Gaussian settings.
Autors: Bofeng Yuan;Hua Sun;Syed Ali Jafar;
Appeared in: IEEE Transactions on Information Theory
Publication date: Oct 2017, volume: 63, issue:10, pages: 6607 - 6621
Publisher: IEEE
 
» Reprogrammable Redundancy for SRAM-Based Cache $V_{\min }$ Reduction in a 28-nm RISC-V Processor
Abstract:
Reducing the operating voltage of digital systems improves energy efficiency, and the minimum operating voltage of a system () is commonly limited by SRAM bitcells. Common techniques to lower SRAM focus on using circuit-level periphery-assist techniques to prevent bitcell failures at low voltage. Alternatively, this paper proposes architecture-level techniques to allow caches to tolerate significant numbers of failing bitcells at low voltage while maintaining correct operation. The presented processor lowers SRAM-based cache using three architectural techniques–bit bypass, dynamic column redundancy, and line disable–that use low-overhead reprogrammable redundancy (RR) to increase the maximum tolerable bitcell failure rate and decrease the minimum operating voltage in processor caches. In a fabricated 28-nm RISC-V-based processor chip, these RR techniques add 2% area overhead to the cache and reduce the of the 1-MB L2 cache by 25%, resulting in a 49% power reduction.
Autors: Brian Zimmer;Pi-Feng Chiu;Borivoje Nikolić;Krste Asanović;
Appeared in: IEEE Journal of Solid-State Circuits
Publication date: Oct 2017, volume: 52, issue:10, pages: 2589 - 2600
Publisher: IEEE
 
» Residual-Consensus Driven Linear Matching
Abstract:
Linear matching (LM) is a simple and effective method for solving image matching problems. In many cases, image matching problems are nonlinear due to involvement of the geometric transformations; therefore, an essential step for utilizing linear models for image matching is to linearize the geometric transformation matrices that introduce nonlinear terms into image matching problems. Existing LM methods usually use low-order transformations to artificially initialize a linear model. In this paper, we propose a residual-consensus driven LM algorithm that generalizes existing LM methods by allowing higher order transformations to automatically initialize a linear model. Based on the observation that transformation models generated from inlier subsets exhibit correlated behaviors (termed residual consensus hereafter), we develop a residual-consensus robust estimation algorithm to project the nontrivial linear transformation problem into a much smaller subspace, and thus enable efficient optimizations through linear programming. The experimental results on synthetic and real databases demonstrate the effectiveness and robustness of the proposed algorithm.
Autors: Hao Wang;
Appeared in: IEEE Transactions on Circuits and Systems for Video Technology
Publication date: Oct 2017, volume: 27, issue:10, pages: 2141 - 2152
Publisher: IEEE
 
» Resilience-Aware Frequency Tuning for Neural-Network-Based Approximate Computing Chips
Abstract:
Unlike conventional ICs, approximate computing chips are less sensitive to hardware errors. This fascinating feature can be utilized to improve the performance of chip design and even change the timing closure procedure of digital circuit design flow. In this paper, we study the potential of resilience-aware circuit clocking scheme, and demonstrate the methodology with advanced neural network (NN)-based accelerator. We propose a novel timing analysis and frequency setting method for NN-based approximate computing circuits based on in-field NN retraining. With the proposed iterative retiming-and-retraining framework, NN-based accelerator can be retrained to operate safely at aggressive operating frequencies compared with the frequency decided purely by statistical timing analysis or Monto Carlo analysis. For nanometer process technology with increasing threats of timing errors induced by process variation, noises, and so on, our retiming-and-retraining method enables higher circuit operating frequency and enables dynamic precision/frequency adjustment for approximate computing circuits. We evaluate the methodology with both the neural and deep learning accelerators in experiments. The experimental results show that timing errors in neural circuits can be effectively tamed for different applications, so that the circuits can operate at higher clocking rates under the specified quality constraint or be dynamically scaled to work at a wide range of frequency states with only minor accuracy losses.
Autors: Ying Wang;Jiachao Deng;Yuntan Fang;Huawei Li;Xiaowei Li;
Appeared in: IEEE Transactions on Very Large Scale Integration Systems
Publication date: Oct 2017, volume: 25, issue:10, pages: 2736 - 2748
Publisher: IEEE
 
» Resilient and Secure Low-Rate Connectivity for Smart Energy Applications through Power Talk in DC Microgrids
Abstract:
The future smart grid is envisioned as a network of interconnected microgrids (MGs) -- small-scale local power networks composed of generators, storage capacities, and loads. MGs bring unprecedented modularity, efficiency, sustainability, and resilience to the power grid as a whole. Due to a high share of renewable generation, MGs require innovative concepts for control and optimization, giving rise to a novel class of smart energy applications, in which communications represent an integral part. In this article, we review power talk, a communication technique specifically developed for direct current MGs, which exploits the communication potential residing within the MG power equipment. Depending on the smart energy application, power talk can be used as either a primary communication enabler or an auxiliary communication system that provides resilient and secure operation. The key advantage of power talk is that it derives its availability, reliability, and security from the very MG elements, outmatching standard off-the shelf communication solutions.
Autors: Cedomir Stefanovic;Marko Angjelichinoski;Pietro Danzi;Petar Popovski;
Appeared in: IEEE Communications Magazine
Publication date: Oct 2017, volume: 55, issue:10, pages: 83 - 89
Publisher: IEEE
 
» Resin Directional Flow and Degree of Cure Sensing Using Chirped Optical Fiber Long Period Gratings
Abstract:
The use of chirped long period gratings (CLPGs) for monitoring the flow, the direction of the flow, and the subsequent cure of an epoxy resin is presented. The asymmetric properties of the CLPG and its sensitivity to refractive index changes were exploited to facilitate the measurement of the direction of the flow. The performances of a continuously chirped LPG (CCLPG) and a step chirped LPG (SCLPG) were compared, with the CCLPG showing improved spatial resolution. The CCLPG and SCLPG were also used to monitor changes in the refractive index of the resin during cure, with the results showing close agreement with measurements undertaken simultaneously using a fiber optic Fresnel refractometer.
Autors: Rebecca Y. N. Wong;Edmon Chehura;Stephen W. James;Ralph P. Tatam;
Appeared in: IEEE Sensors Journal
Publication date: Oct 2017, volume: 17, issue:20, pages: 6605 - 6614
Publisher: IEEE
 
» Resonances of Characteristic Modes for Perfectly Conducting Objects
Abstract:
Resonances, i.e., extrema of the eigenvalues of characteristic modes for closed perfectly conducting objects are investigated. The characteristic modal solutions based on the electric, magnetic, and combined field integral operators (EFIO, MFIO, and CFIO) are studied and compared with analytical solutions for a sphere. All these formulations are found to capture both external (radiating) and internal (cavity) resonances predicted by the analytical expressions. At the internal resonances, the eigenvalues obtained with the EFIO- and MFIO-based approaches are not correct, and the corresponding modes are nonunique. These solutions also exhibit a strong duality between the electric (TM) and magnetic (TE) type modes. A connection is found between the external and internal resonances and the condition numbers of the matrices. The modal expansion of the CFIO-based solution is correct, even though it also experiences the nonuniqueness of the EFIO- and MFIO-based solutions.
Autors: Joni Lappalainen;Pasi Ylä-Oijala;Dimitrios C. Tzarouchis;Ari Sihvola;
Appeared in: IEEE Transactions on Antennas and Propagation
Publication date: Oct 2017, volume: 65, issue:10, pages: 5332 - 5339
Publisher: IEEE
 
» Resonant-Based Backstepping Direct Power Control Strategy for DFIG Under Both Balanced and Unbalanced Grid Conditions
Abstract:
This paper proposes a resonant-based backstepping direct power control (BS-DPC) strategy for doubly-fed induction generator (DFIG) under both balanced and unbalanced grid conditions. Proper formulae for the BS-DPC strategy are obtained based on the elaborated analysis of the mathematical model of DFIG. The influence of the unbalanced grid voltage on the normal BS-DPC is analyzed. Furthermore, a resonant-based improved strategy is proposed to achieve different control targets under unbalanced grid condition without the need of decomposition of positive- and negative-sequence components. Comparative experimental studies of the resonant-based BS-DPC and the normal BS-DPC for DFIG are conducted to validate the effectiveness of the proposed strategy under both balanced and unbalanced grid conditions. In addition, the experimental results also prove that the proposed resonant-based BS-DPC can achieve a satisfying transient performance.
Autors: Xiaohe Wang;Dan Sun;Z. Q. Zhu;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4821 - 4830
Publisher: IEEE
 
» Resource allocation for elastic optical networks using geometric optimization
Abstract:
Resource allocation with quality of service constraints is one of the most challenging problems in elastic optical networks that is normally formulated as a mixed-integer nonlinear optimization program. In this paper, we focus on novel properties of geometric optimization and provide a heuristic approach for resource allocation that is much faster than its mixed-integer nonlinear counterpart. Our heuristic consists of two main parts for routing/traffic ordering and power/spectrum assignment. It aims at minimization of the transmit optical power and spectrum usage constrained to the quality of service and physical requirements. We consider three routing and three traffic ordering procedures and compare them in terms of total transmit optical power, total received noise power, and total nonlinear interference including self- and cross-channel interferences. We propose a posynomial expression for the signal-to-noise ratio in which fiber nonlinearities and amplified spontaneous emission noise have been addressed. We also propose posynomial expressions that relate the modulation spectral efficiency to its corresponding minimum required signal-to-noise ratio. We then use the posynomial expressions to develop six geometric formulations for the power/spectrum assignment part of the heuristic that are different in run time, complexity, and accuracy. Simulation results demonstrate that the proposed solution has very good accuracy and much lower computational complexity in comparison with mixedinteger nonlinear formulation. As an example, for the European Cost239 optical network with 126 transmit transponders, the geometric formulation can be more than 22 times faster than its mixed-integer nonlinear counterpart. Numerical results also reveal that, in long-haul elastic optical networks, considering the product of the number of common fiber spans and the transmission bit rate is a better goal function for routing/traffic ordering that can reduce the total transmit optical fibe- (total accumulated noise and nonlinear interference) up to 20% (15%).
Autors: Mohammad Hadi;Mohammad Reza Pakravan;
Appeared in: IEEE/OSA Journal of Optical Communications and Networking
Publication date: Oct 2017, volume: 9, issue:10, pages: 889 - 899
Publisher: IEEE
 
» Resource Allocation for Multicarrier Device-to-Device Video Transmission: Symbol Error Rate Analysis and Algorithm Design
Abstract:
In resource allocation for a device-to-device (D2D) video transmission system, the performance improvement by applying the exact symbol error rate (SER) is compared with the conventional signal-to-interference-plus-noise-ratio-based SER evaluation method that uses a Gaussian approximation (GA) for the aggregated interference. An analytical SER expression for a D2D system using multicarrier bandlimited QAM is derived and then used in the resource allocation algorithm. We consider centralized resource allocation for the D2D system, given knowledge of the channel state information and the rate distortion information of the video streams, and propose an iterative algorithm for subcarrier assignment and power allocation. Bit-level simulations for different numbers of D2D pairs demonstrate a considerable improvement on user capacity and video peak signal-to-noise ratio by incorporating the proposed SER expression compared with the GA. By invoking the conditions under which the central limit theorem holds, and comparing these conditions with the number of interferers and the power ratio of the dominant interferer in the simulated D2D system, we also study why the GA for the interference degrades performance.
Autors: Peizhi Wu;Pamela C. Cosman;Laurence B. Milstein;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4446 - 4462
Publisher: IEEE
 
» Resource Allocation in Non-Orthogonal and Hybrid Multiple Access System With Proportional Rate Constraint
Abstract:
Non-orthogonal multiple access (NOMA), which has attracted a lot of attention recently due to its superior spectral efficiency, could play a vital role in improving the capacity of future networks. In this paper, a resource allocation scheme is developed for a downlink multi-user NOMA system. An optimization problem is formulated to maximize the sum rate under the total power and proportional rate constraints. Due to the complexity of computing the optimal solution, we develop a low complexity sub-optimal solution for a two-user scenario and then extend it to the multi-user case by proposing a user-pairing approach as well as a number of power allocation techniques that facilitate dealing with a large number of users in NOMA system. Simulation results support the effectiveness of the proposed approaches and show the close performance to the optimal one. In addition, we propose a new hybrid multiple access technique that combines the properties of NOMA and the orthogonal frequency division multiple access. Simulation results show that the proposed hybrid method provides better performance than NOMA in terms of the overall achievable sum rate and the coverage probability.
Autors: Ziad Qais Al-Abbasi;Daniel K. C. So;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6309 - 6320
Publisher: IEEE
 
» Restoration-Based Merging of Functional Test Sequences
Abstract:
This paper develops a merging procedure for functional test sequences that achieves test compaction for a pool of functional test sequences by reducing the number of sequences in the pool. The procedure has the following new features: 1) in contrast to existing selection procedures, the merging procedure described in this paper increases the fault coverage of test sequences in the pool, thus enhancing the ability to reduce the number of sequences and 2) in contrast to existing procedures that concatenate or merge test sequences, the procedure described in this paper does not increase the lengths of the sequences it merges. The procedure is based on the concept of restoration of test vectors. In the context of test sequence merging, restoration consists of copying test vectors from a test sequence into a test sequence in order to allow to detect faults that detects. The merging procedure focuses on the removal of one test sequence at a time by restoring test vectors from into other sequences, allowing them to detect the faults that detects. Experimental results for benchmark circuits demonstrate that the procedure reduces the number of sequences in a pool significantly.
Autors: Irith Pomeranz;
Appeared in: IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems
Publication date: Oct 2017, volume: 36, issue:10, pages: 1739 - 1749
Publisher: IEEE
 
» Revealing the Nitridation Effects on GaN Surface by First-Principles Calculation and X-Ray/Ultraviolet Photoemission Spectroscopy
Abstract:
In this paper, we report a systematic study of the nitridation effects on GaN surface by first-principles calculations and X-ray/ultraviolet photoemission spectroscopy (XPS/UPS). According to the calculated electronic structures, two surface bands (i.e., the upper band and the lower band) can be seen within the bandgap for the typical surface configurations that may occur in the experimental condition as a result of surface reconstruction. By the deployment of sufficient nitridation, the energy positions of the lower band are modified toward the valence band by ~1 eV, resulting in the overlapping of the lower surface band with the valence band. Meanwhile, the upper surface band is also modified toward the valence band, but by a smaller amount. The modification to the positions of the surface bands is furthermore manifested by XPS/UPS spectra characterization performed on GaN sample that underwent surface treatment with low-energy remote N2 plasma. The theoretical and experimental results insightfully proclaim the nitridation effects on material properties at atomic level, and support a surface-state ionization model for the GaN band-edge (3.4 eV) emission in metal-AlGaN/GaN Schottky-on-heterojunction diode under forward bias.
Autors: Zhaofu Zhang;Baikui Li;Qingkai Qian;Xi Tang;Mengyuan Hua;Baoling Huang;Kevin J. Chen;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4036 - 4043
Publisher: IEEE
 
» Review of Fast Calculation Techniques for Computer-Generated Holograms With the Point-Light-Source-Based Model
Abstract:
Computer-generated holograms (CGHs) are a key technology in electroholography systems; however, heavy calculations are required to calculate CGHs. We review fast calculation techniques for CGH calculation of a point-light-source-based model, which is a simple and general model of a three-dimensional object in an electroholography system. To reduce the calculation time, many methods that reduce the temporal and spatial redundancy of the CGH calculation have been developed (e.g., look-up table method, the wavefront recording plane method, and other approximation techniques). The implementation of such methods on parallel computers (e.g., graphic processing unit and field programmable gate arrays) has also been reported.
Autors: Takashi Nishitsuji;Tomoyoshi Shimobaba;Takashi Kakue;Tomoyoshi Ito;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2447 - 2454
Publisher: IEEE
 
» Review of Silicon Carbide Power Devices and Their Applications
Abstract:
Silicon carbide (SiC) power devices have been investigated extensively in the past two decades, and there are many devices commercially available now. Owing to the intrinsic material advantages of SiC over silicon (Si), SiC power devices can operate at higher voltage, higher switching frequency, and higher temperature. This paper reviews the technology progress of SiC power devices and their emerging applications. The design challenges and future trends are summarized at the end of the paper.
Autors: Xu She;Alex Q. Huang;Óscar Lucía;Burak Ozpineci;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8193 - 8205
Publisher: IEEE
 
» Review: Human Intracortical Recording and Neural Decoding for Brain–Computer Interfaces
Abstract:
Brain–computer interfaces (BCIs) use neural information recorded from the brain for the voluntary control of external devices. The development of BCI systems has largely focused on improving functional independence for individuals with severe motor impairments, including providing tools for communication and mobility. In this review, we describe recent advances in intracortical BCI technology and provide potential directions for further research.
Autors: David M. Brandman;Sydney S. Cash;Leigh R. Hochberg;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Oct 2017, volume: 25, issue:10, pages: 1687 - 1696
Publisher: IEEE
 
» Reweighted Anisotropic Total Variation Minimization for Limited-Angle CT Reconstruction
Abstract:
Limited-angle problems encountered in computed tomography (CT) often necessitate image reconstruction using projection data from a particular angle range. To solve this severely ill-posed problem, prior information is utilized to constrain the problem. As a special case of compressed sensing, a total variation (TV) transform with an -norm image gradient is utilized in most cases, and manages to obtain very impressive reconstruction results. However, it is unfit for limited-angle problems owing to its isotropic property. This paper proposes a new iteratively reweighted anisotropic TV (ATV) method, in which a reweighted technique is incorporated into the idea of ATV. Our strategy successfully combines their merits and results in significantly improved performance. By using the reweighted technique, we are able to approximate the most direct measure of sparsity—-norm—better than -norm. As a result, the property of image sparsity can be utilized more efficiently. Because TV is isotropic, which prevents detection of blurred edges caused by missing angle ranges and may weaken edge-preserving ability along nonblurred directions, we consider the angle range of the data as additional prior information by assigning different weights to different directions; this allows the anisotropic property to be utilized. Therefore, the blurred directions can be prevented from affecting edge detection, and better reconstruction results can be achieved. To demonstrate the advantages of our method, we perform reconstruction using projection data from phantom CT scans and actual CT scans. We conducted comprehensive comparison between our method and many existing TV-based methods. Both qualitative and quant- tative results are presented.
Autors: Ting Wang;Katsuhiro Nakamoto;Heye Zhang;Huafeng Liu;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Oct 2017, volume: 64, issue:10, pages: 2742 - 2760
Publisher: IEEE
 
» RF Behavior of a 220/251.5-GHz, 2-MW, Triangular Corrugated Coaxial Cavity Gyrotron
Abstract:
In this paper, RF behavior studies of a dual regime coaxial cavity gyrotron designed for electron cyclotron resonance heating and current drive of magnetically confined plasmas in the future fusion reactors are presented. Considering all the design constraints, the mode pair is chosen as and for operation at 220 and 251.5 GHz, respectively. The interaction circuit is initially designed through the cold cavity design. A triangular corrugated insert offers good mode selection and also reduces the localized heating problem. Single mode computations are carried out to optimize the beam parameters for the maximum efficiency of the chosen mode pair. Time-dependent multimode simulations are carried out to conform the power in the desired mode pair and the possibility of power in the competing modes. Start-up analyses are performed before and after space-charge neutralization with nonuniform magnetic field using nominal electron beam parameters obtained from magnetron injection gun calculations. These studies ensure that the continuous wave operation of a coaxial cavity gyrotron is possible with the output power of ≈2 MW with the chosen mode pair.
Autors: S. Yuvaraj;M. V. Kartikeyan;M. K. Thumm;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4287 - 4294
Publisher: IEEE
 
» RF Performance of In Situ SiNx Gate Dielectric AlGaN/GaN MISHEMT on 6-in Silicon-on-Insulator Substrate
Abstract:
A high power-added efficiency and low dynamic on-resistance ( AlGaN/GaN metal–insulator–semiconductor high-electron mobility transistor (MISHEMT) with in situ SiNx insulator design was demonstrated on 150-mm silicon-on-insulator (SOI) substrate. Compared to traditional high-resistivity Si substrate, SiNx/AlGaN/GaN MISHEMT grown on the SOI 5--thick Si active layer performed better tensile stress relaxation and surface flatness. Based on Hall measurement results, electron mobility and the sheet charge density on SOI substrate were improved simultaneously owing to a lower-defect density which is also proofed by pulse measurement and low-frequency noise measurement. Due to the low-feedback substrate capacitance, the bandwidth, and the linearity were also improved simultaneously by SOI substrate design.
Autors: Hsien-Chin Chiu;Hou-Yu Wang;Li-Yi Peng;Hsiang-Chun Wang;Hsuan-Ling Kao;Chih-Wei Hu;Rong Xuan;
Appeared in: IEEE Transactions on Electron Devices
Publication date: Oct 2017, volume: 64, issue:10, pages: 4065 - 4070
Publisher: IEEE
 
» RF-MEMS-Based Bandpass-to-Bandstop Switchable Single- and Dual-Band Filters With Variable FBW and Reconfigurable Selectivity
Abstract:
Bandpass (BP)-to-bandstop (BS) switchable filters using radio frequency microelectromechanical system switch are presented here. The filters are implemented in both single- and dual-band versions with variable fractional bandwidth (FBW). Tuning of transmission zeros (TZs) and transmission poles (TPs) for BP filter (BPF) and BS filter (BSF), respectively, is achieved in both single- and dual-band cases leading to reconfigurable selectivity. The first odd-mode frequency of the filter is suppressed using a fixed capacitor and the second odd mode is brought closer to the first even-mode with another variable capacitor to form the passband(s). The second capacitor tunes both the second odd mode and TZs (for BPF) or TPs (for BSF) minimizing the requirement of any extra tuning element. In a single-band fabricated BPF, tuning second odd mode gives the FBW variation of 9.3%–72.7% with TZ on the lower side and 5.6%–55.6% with TZ on the higher side of the passband. The 15-dB FBW of a single-band BSF having TP on both sides of the stopband varies over 5.2%–20.7%. The two passbands of a dual-band BPF independently vary over 4.5%–24% and 4.5%–13%. Also, the 15-dB FBW of the first and second stopbands of BSF independently varies over 6.5%–13.2% and 1.5%–3.6%, respectively.
Autors: Nagendra Kumar;Yatendra Kumar Singh;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Oct 2017, volume: 65, issue:10, pages: 3824 - 3837
Publisher: IEEE
 
» Riemannian Approaches in Brain-Computer Interfaces: A Review
Abstract:
Although promising from numerous applications, current brain–computer interfaces (BCIs) still suffer from a number of limitations. In particular, they are sensitive to noise, outliers and the non-stationarity of electroencephalographic (EEG) signals, they require long calibration times and are not reliable. Thus, new approaches and tools, notably at the EEG signal processing and classification level, are necessary to address these limitations. Riemannian approaches, spearheaded by the use of covariance matrices, are such a very promising tool slowly adopted by a growing number of researchers. This article, after a quick introduction to Riemannian geometry and a presentation of the BCI-relevant manifolds, reviews how these approaches have been used for EEG-based BCI, in particular for feature representation and learning, classifier design and calibration time reduction. Finally, relevant challenges and promising research directions for EEG signal classification in BCIs are identified, such as feature tracking on manifold or multi-task learning.
Autors: Florian Yger;Maxime Berar;Fabien Lotte;
Appeared in: IEEE Transactions on Neural Systems and Rehabilitation Engineering
Publication date: Oct 2017, volume: 25, issue:10, pages: 1753 - 1762
Publisher: IEEE
 
» Rise-Time Improvement in Bipolar Pulse Solid-State Marx Modulators
Abstract:
This paper presents the effect of stray capacitances in bipolar (negative and/or positive) pulses generated by the two different topologies of the solid-state Marx modulators. According to the analysis, the stray capacitances influence the energy transfer from the Marx modulator capacitors to the load affecting the bipolar (negative and/or positive) pulse rise time. This paper deals with the structure design to reduce the influence of the stray capacitance and to improve the pulse rise time of these bipolar solid-state Marx modulators. A four-stage laboratory prototype of the two topologies has been assembled using 1200-V insulated gate bipolar transistors and diodes, operating with 1000-V dc input voltage and 1-kHz frequency, producing 4-kV bipolar pulses, with 5- pulse duration and 120-ns rise time, into a resistive load.
Autors: Hiren Canacsinh;J. Fernando Silva;L. M. Redondo;
Appeared in: IEEE Transactions on Plasma Science
Publication date: Oct 2017, volume: 45, issue:10, pages: 2656 - 2660
Publisher: IEEE
 
» Risk-Averse Energy Trading in Multienergy Microgrids: A Two-Stage Stochastic Game Approach
Abstract:
Multienergy microgrids are a promising solution to improve overall energy (electricity, cooling, heating, etc.) efficiency. In this paper, a new optimal energy trading strategy is developed considering the risk from uncertain energy supply and demand in a set of individual multienergy microgrids. According to the historical data about energy supply of each microgrid, an aggregator aims to maximize each microgrid's profit while minimizing the risk of overbidding for renewable energy resources trading based microgrids. A novel two-stage stochastic game model with Cournot Nash pricing mechanism and the conditional value-at-risk criterion is proposed to characterize the payoff function of each microgrid. The sample average approximation (SAA) technique is employed to approximate the stochastic Nash equilibrium of the game model. The existence of the SAA Nash equilibrium is investigated and the corresponding Nash equilibrium seeking algorithm is also realized in a distributed manner. The proposed method is validated by numerical simulations on real-world data collected in Australia, and the results show that the SAA Nash equilibrium based strategy can effectively reduce the risk of not meeting the demand and improve the economic benefits for each microgrid.
Autors: Chaojie Li;Yan Xu;Xinghuo Yu;Caspar Ryan;Tingwen Huang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2620 - 2630
Publisher: IEEE
 
» Roadside Unit Caching: Auction-Based Storage Allocation for Multiple Content Providers
Abstract:
Recent improvements in vehicular ad hoc networks are accelerating the realization of intelligent transportation system (ITS), which not only provides road safety and driving efficiency, but also enables infotainment services. Since data dissemination plays an important part in ITS, recent studies have found caching as a promising way to promote the efficiency of data dissemination against rapid variation of network topology. In this paper, we focus on the scenario of roadside unit (RSU) caching, where multiple content providers (CPs) aim to improve the data dissemination of their own contents by utilizing the storages of RSUs. To deal with the competition among multiple CPs for limited caching facilities, we propose a multi-object auction-based solution, which is sub-optimal and efficient to be carried out. A caching-specific handoff decision mechanism is also adopted to take advantages of the overlap of RSUs. Simulation results show that our solution leads to a satisfactory outcome.
Autors: Zhiwen Hu;Zijie Zheng;Tao Wang;Lingyang Song;Xiaoming Li;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6321 - 6334
Publisher: IEEE
 
» Robot Patient Design to Simulate Various Patients for Transfer Training
Abstract:
To improve the patient transfer skill of nursing education students, we developed a robot patient that can simulate three categories of patients: 1) patients whose movements are affected by paralysis; 2) patients whose movements are sensitive to pain with painful expression; and 3) patients whose movements are constrained by medical devices. By practicing with the robot patient, nursing students can learn the skills required for interacting with various patients. To simulate trunk movements of these different patients, novel waist and hip joints with hardware-inherent compliance and force-sensing capability were proposed. In addition, control methods were developed and the parameters were tuned based on actual patient videos. To evaluate the developed robot, nursing teachers performed trials of transferring the robot patient as they would transfer an actual patient. The nursing teachers scored the robot patients based on a checklist. Moreover, subjective evaluations of a questionnaire were performed by the nursing teachers. The results showed that the nursing teachers performed most of the required skills of the checklist and agreed regarding the learning effectiveness of the robot. They recommended training nursing students using the robot patient in the questionnaire. Finally, hugging speed comparison showed that the nurses slow down the speed when dealing with a robot patient with painful expression.
Autors: Zhifeng Huang;Chingszu Lin;Masako Kanai-Pak;Jukai Maeda;Yasuko Kitajima;Mitsuhiro Nakamura;Noriaki Kuwahara;Taiki Ogata;Jun Ota;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Oct 2017, volume: 22, issue:5, pages: 2079 - 2090
Publisher: IEEE
 
» Robotic Through-Wall Imaging: Radio-Frequency Imaging Possibilities with Unmanned Vehicles.
Abstract:
Using electromagnetic waves for sensing has been of interest to the research community for many years. More recently, sensing with lower frequencies, such as with radio waves and even with Wi-Fi, has become of interest due to factors like safety and availability of the transceivers. In particular, there has been a considerable interest in using radio-frequency (RF) signals to sense and obtain information about the environment in various contexts, such as imaging, localization, tracking, and occupancy estimation [1]-[10]. See-through imaging (also known as through-wall imaging) has, in particular, been of considerable interest to the research community. The ability to see through occluded objects can be beneficial to many applications, such as search and rescue, surveillance and security, archaeological discovery, detection/classification of occluded objects, and medical applications. Despite great interest in this area, however, see-through imaging is still a considerably challenging problem, especially with everyday RF signals.
Autors: Saandeep Depatla;Chitra R. Karanam;Yasamin Mostofi;
Appeared in: IEEE Antennas and Propagation Magazine
Publication date: Oct 2017, volume: 59, issue:5, pages: 47 - 60
Publisher: IEEE
 
» Robust 2-D–3-D Registration Optimization for Motion Compensation During 3-D TRUS-Guided Biopsy Using Learned Prostate Motion Data
Abstract:
In magnetic resonance (MR)-targeted, 3-D transrectal ultrasound (TRUS)-guided biopsy, prostate motion during the procedure increases the needle targeting error and limits the ability to accurately sample MR-suspicious tumor volumes. The robustness of the 2-D–3-D registration methods for prostate motion compensation is impacted by local optima in the search space. In this paper, we analyzed the prostate motion characteristics and investigated methods to incorporate such knowledge into the registration optimization framework to improve robustness against local optima. Rigid motion of the prostate was analyzed adopting a mixture-of-Gaussian (MoG) model using 3-D TRUS images acquired at bilateral sextant probe positions with a mechanically assisted biopsy system. The learned motion characteristics were incorporated into Powell’s direction set method by devising multiple initial search positions and initial search directions. Experiments were performed on data sets acquired during clinical biopsy procedures, and registration error was evaluated using target registration error (TRE) and converged image similarity metric values after optimization. After incorporating the learned initialization positions and directions in Powell’s method, 2-D–3-D registration to compensate for motion during prostate biopsy was performed with rms ± std TRE of 2.33 ± 1.09 mm with ~3 s mean execution time per registration. This was an improvement over 3.12 ± 1.70 mm observed in Powell’s standard approach. For the data acquired under clinical protocols, the converged image similarity metric value improved in ≥8% of the registrations whereas it degraded only ≤1% of the registrations. The reported improvements in optimization indicate useful advancement- in robustness to ensure smooth clinical integration of a registration solution for motion compensation that facilitates accurate sampling of the smallest clinically significant tumors.
Autors: Tharindu De Silva;Derek W. Cool;Jing Yuan;Cesare Romagnoli;Jagath Samarabandu;Aaron Fenster;Aaron D. Ward;
Appeared in: IEEE Transactions on Medical Imaging
Publication date: Oct 2017, volume: 36, issue:10, pages: 2010 - 2020
Publisher: IEEE
 
» Robust Adaptive Beamforming Against Mutual Coupling Based on Mutual Coupling Coefficients Estimation
Abstract:
In an adaptive beamforming system, the mutual coupling effects among the array elements can seriously degrade the system performance. In this paper, we propose a robust adaptive beamforming algorithm using a uniform linear array (ULA) to mitigate the mutual coupling effects. The proposed algorithm is based on the fact that the mutual coupling matrix (MCM) of a ULA can be approximated as a banded symmetric Toeplitz matrix as the mutual coupling between two sensors is inversely related to their separation and is negligible for a few wavelengths away. By exploiting the structural characteristics of the MCM, a subspace-based method is used to estimate the mutual coupling coefficients of the ULA that yield a closed-form solution, and the MCM is further constructed. Then, the constructed MCM and array received data are used to reconstruct the interference-plus-noise covariance (INC) matrix. Finally, the robust adaptive beamformer is created through using the Capon principle and the reconstructed INC matrix. Unlike most of the existing algorithms, the proposed algorithm only requires prior knowledge of the array geometry. Simulation results indicate that our approach outperforms the compared algorithms in the presence of unknown mutual coupling and can achieve a performance close to the theoretical optimal value.
Autors: Zhi Zheng;Kehong Liu;Wen-Qin Wang;Yuxuan Yang;Jiao Yang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9124 - 9133
Publisher: IEEE
 
» Robust Adaptive Control for Dynamic Positioning of Ships
Abstract:
In this paper, a robust adaptive control scheme with the global asymptotic stability with respect to positioning errors is proposed for dynamic positioning (DP) of ships in the presence of time-varying unknown bounded environmental disturbances. The unknown environmental disturbances are expressed as the outputs of a linear exosystem with unknown parameters and all eigenvalues of system matrix lying on the imaginary axis. On the basis of this exosystem, the disturbances are further represented as the outputs of a linear model of canonical form with unknown disturbances being inputs by a multivariate linear regression model whose regressor is the state vector of the linear model and whose regression parameters depend on unknown parameters of the linear exosystem. This representation allows us to construct an observer to estimate the unavailable state vector (regressor) in the linear model and hence convert the disturbance compensation control for the DP of ships to an adaptive control problem. Then, a robust adaptive control law for the DP of ships is designed incorporating the constructed observer and the projection algorithm into the vectorial backstepping method. The global asymptotic stability with respect to positioning errors of the DP closed-loop control system is proved applying Lyapunov stability theory and Barbalat's lemma. Finally, simulation results on a supply ship Northern Clipper in two different disturbance cases and simulation comparisons with an existing DP adaptive robust control scheme demonstrate more effectiveness and less conservativeness of our proposed control scheme.
Autors: Xin Hu;Jialu Du;Yuqing Sun;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 826 - 835
Publisher: IEEE
 
» Robust Adaptive State Constraint Control for Uncertain Switched High-Order Nonlinear Systems
Abstract:
Under the weaker conditions on system power and nonlinear functions, this paper focuses on the robust adaptive state constraint control for a class of uncertain switched high-order nonlinear systems. With the help of p-times differentiable unbounded function, a robust adaptive state-feedback controller is designed by combining the homogeneous domination approach with parameter separation principle. When the initial condition satisfies a suitable requirement, it is shown that all signals of the closed-loop system are bounded and system state is within a prespecified limit range by the proposed controller. As a practical application, the design scheme is utilized to the continuous stirred tank reactor with two modes feed stream. To further demonstrate the efficiency of the proposed controller, another numerical example is given.
Autors: Liang Liu;Xuebo Yang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8108 - 8117
Publisher: IEEE
 
» Robust and Fast Segmentation Based on Fuzzy Clustering Combined with Unsupervised Histogram Analysis
Abstract:
Many real-time engineering applications have used histogram thresholding methods that failed to segment images whose histogram had only one peak. A fuzzy c-means cluster algorithm (FCM), in contrast, can segment this type of image but at the cost of time. To improve unsupervised segmentation, the authors developed a new method for fast and efficient segmentation based on automatic histogram analysis of acquired images and a combined FCM and intensity transformation (HIST_FCM_IT) approach. The first part of the algorithm uses parabolic approximation for peak evaluation, and the second modifies image intensity to allow the partition matrix to be rapidly constant.
Autors: Alban Ngatchou;Laurent Bitjoka;Etienne Mfoumou;Ousman Boukar;Mitherand Ngatcheu;Martin Ngueguim;
Appeared in: IEEE Intelligent Systems
Publication date: Oct 2017, volume: 32, issue:5, pages: 6 - 13
Publisher: IEEE
 
» Robust Constrained Attitude Control of Spacecraft Formation Flying in the Presence of Disturbances
Abstract:
In this paper, the robust control problem for spacecraft formation flying in virtual structure algorithm is addressed. The effects of external disturbances, model uncertainties, sensor noises, and actuator saturation are taken into account. A robust controller based on μ-synthesis is first designed to overcome the environmental disturbances. To obtain a control law with lower order, an H-based linear matrix inequality controller is designed, using the linearized model with uncertainties. Then, a robust adaptive controller, based on the Lyapunov stability theorem, is presented to overcome a broader range of model uncertainties, which also guarantees the stability. From a comparison viewpoint, the numerical results are also demonstrated to show the performance of the robust controllers in tracking the desired attitude and position.
Autors: Bahare Shahbazi;Maryam Malekzadeh;Hamid Reza Koofigar;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2534 - 2543
Publisher: IEEE
 
» Robust Control of Robot Manipulators Using Inclusive and Enhanced Time Delay Control
Abstract:
Thanks to its simplicity and robustness, time delay control (TDC) has been recognized as a simple and yet effective alternative to robot model-based controls and/or intelligent controls. An inclusive and enhanced formulation of TDC for robust control of robot manipulators is presented in this paper. The proposed formulation consists of three intuitive terms: 1) time delay estimation (TDE), inherited from the original TDC, for cancellation of mostly continuous nonlinearities; 2) nonlinear desired error dynamics (DED) (i.e., a “mass”–“nonlinear damper”– “nonlinear spring” system) injection term; and 3) a TDE error correction term based on a nonlinear sliding surface. The proposed TDC formulation has an inclusive structure. Depending on the gain/parameter set chosen, the proposed formulation can become Hsia's formulation, Jin's formulations including a type of terminal sliding mode control (SMC), an SMC with a switching signum function, or a novel enhanced formulation. Experimental comparisons were made using a programmable universal manipulator for assembly-type robot manipulator with various parameter sets for the proposed control. Among them, the highest position tracking accuracy was obtained by using a terminal sliding DED with a terminal sliding correction term.
Autors: Maolin Jin;Sang Hoon Kang;Pyung Hun Chang;Jinoh Lee;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Oct 2017, volume: 22, issue:5, pages: 2141 - 2152
Publisher: IEEE
 
» Robust Deadlock Avoidance for Sequential Resource Allocation Systems With Resource Outages
Abstract:
While the supervisory control (SC) problem of (maximally permissive) deadlock avoidance for sequential resource allocation systems (RASs) has been extensively studied in the literature, the corresponding results that are able to address potential resource outages are quite limited, both, in terms of their volume and their control capability. This paper leverages the recently developed SC theory for switched discrete event systems (s-DES) in order to provide a novel systematic treatment of this more complicated version of the RAS deadlock avoidance problem. Following the modeling paradigm of s-DES, both the operation of the considered RAS and the corresponding maximally permissive SC policy are decomposed over a number of operational modes that are defined by the running sets of the failing resources. In particular, the target supervisor must be decomposed to a set of “localized predicates,” where each predicate is associated with one of the operational modes. A significant part, and a primary contribution, of this paper concerns the development of these localized predicates that will enable the formal characterization and the effective computation of the sought supervisor. With these predicates available, a distributed representation for the sought supervisor that is appropriate for real-time implementation is eventually obtained through an adaptation of the relevant distributed algorithm that is provided by the current s-DES SC theory. Note to Practitioners—This paper extends the existing theory of deadlock avoidance for buffer-space allocation in flexibly automated production systems so that it accounts for disruptive effects due to potential temporary outages of some of the system servers. The set of the failing servers at any time instant defines the corresponding operational mode for the underlying resource allocation system. The primary problem that is addressed by this paper is the syn- hesis of a resource allocation policy that will ensure the ability of all process instances that do not require the failing resources in a particular mode, to execute repetitively and complete successfully while the system remains in that mode. In line with some past literature on this problem, we call the corresponding supervisory control problem as “robust deadlock avoidance,” and we leverage results from the recently emerged theory for modeling and control of switched discrete event systems in order to characterize and compute a maximally permissive solution for it.
Autors: Spyros Reveliotis;Zhennan Fei;
Appeared in: IEEE Transactions on Automation Science and Engineering
Publication date: Oct 2017, volume: 14, issue:4, pages: 1695 - 1711
Publisher: IEEE
 
» Robust Estimation of Sparse Narrowband Spectra from Neuronal Spiking Data
Abstract:
Objective: Characterizing the spectral properties of neuronal responses is an important problem in computational neuroscience, as it provides insight into the spectral organization of the underlying functional neural processes. Although spectral analysis techniques are widely used in the analysis of noninvasive neural recordings such as EEG, their application to spiking data is limited due to the binary and nonlinear nature of neuronal spiking. In this paper, we address the problem of estimating the power spectral density of the neural covariate driving the spiking statistics of a neuronal population from binary observations. Methods: We consider a neuronal ensemble spiking according to Bernoulli statistics, for which the conditional intensity function is given by the logistic map of a harmonic second-order stationary process with sparse narrowband spectra. By employing sparsity-promoting priors, we compute the maximum a posteriori estimate of the power spectral density of the process from the binary spiking observations. Furthermore, we construct confidence intervals for these estimates by an efficient posterior sampling procedure. Results: We provide simulation studies which reveal that our method outperforms the existing methods for extracting the frequency content of spiking data. Application of our method to clinically recorded spiking data from a patient under general anesthesia reveals a striking resemblance between our estimated power spectral density and that of the local field potential signal. This result corroborates existing findings regarding the salient role of the local field potential as a major neural covariate of rhythmic cortical spiking activity under anesthesia. Conclusion: Our technique allows us to analyze the harmonic structure of spiking activity in a robust fashion, independently of the local field potentials, and without any prior assumption of the spect- al spread and content of the underlying neural processes. Significance: Other than its usage in the spectral analysis of neuronal spiking data, our technique can be applied to a wide variety of binary data, such as heart beat data, in order to obtain a robust spectral representation.
Autors: Sina Miran;Patrick L. Purdon;Emery N. Brown;Behtash Babadi;
Appeared in: IEEE Transactions on Biomedical Engineering
Publication date: Oct 2017, volume: 64, issue:10, pages: 2462 - 2474
Publisher: IEEE
 
» Robust Finite-Time Control for Autonomous Operation of an Inverter-Based Microgrid
Abstract:
Recently, more and more small-scale renewable generation sources based distributed generators are integrated to the existing power network through power electronic-based converters. Microgrid has been proposed as a solution to meet the challenges posed by highly intermittent renewable generations. To address the fast response and complex operating conditions of various inverters in an autonomous microgrid, this paper proposes a robust finite-time control algorithm for frequency/voltage regulation and active/reactive power control. The major advantages of the proposed control algorithm include, being robust and stable against various load disturbances, unmodeled dynamics and system parameter perturbations; enabling flexible convergence time according to user preferences and different operating conditions' requirements. The finite-time convergence of the robust control algorithm is guaranteed through rigorous analysis and the balance between control accuracy and chattering suppression is investigated. Simulation results demonstrate the effectiveness of the proposed robust finite-time control algorithm.
Autors: Yinliang Xu;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2717 - 2725
Publisher: IEEE
 
» Robust High Resolution Time of Arrival Estimation for Indoor WLAN Ranging
Abstract:
This paper proposes a novel robust high resolution time of arrival (TOA) estimation method for IEEE 802.11g/n range estimation in indoor environments. The algorithm identifies the TOA of ranging symbols by means of baseband signal processing using a single 802.11 channel. A subsample signal model provides high timing resolution. The CLEAN deconvolution algorithm, coupled with a parameter optimization step, provides robustness to multipath. Two ranging symbols are investigated: the 802.11 standard long training sequence and an impulsive symbol. In real-world wireless line of sight experiments, at ranges of up to 25 m, the method when applied to impulsive symbols was found to provide median ranging errors of 0.34 and 0.93 m with directional and omnidirectional antennas, respectively.
Autors: Ahmed Makki;Abubakr Siddig;Chris J. Bleakley;
Appeared in: IEEE Transactions on Instrumentation and Measurement
Publication date: Oct 2017, volume: 66, issue:10, pages: 2703 - 2710
Publisher: IEEE
 
» Robust Intensity-Based Localization Method for Autonomous Driving on Snow–Wet Road Surface
Abstract:
Autonomous vehicles are being developed rapidly in recent years. In advance implementation stages, many particular problems must be solved to bring this technology into the market place. This paper focuses on the problem of driving in snow and wet road surface environments. First, the quality of laser imaging detection and ranging (LIDAR) reflectivity decreases on wet road surfaces. Therefore, an accumulation strategy is designed to increase the density of online LIDAR images. In order to enhance the texture of the accumulated images, principal component analysis is used to understand the geometrical structures and texture patterns in the map images. The LIDAR images are then reconstructed using the leading principal components with respect to the variance distribution accounted by each eigenvector. Second, the appearance of snow lines deforms the expected road context in LIDAR images. Accordingly, the edge profiles of the LIDAR and map images are extracted to encode the lane lines and roadside edges. Edge matching between the two profiles is then calculated to improve localization in the lateral direction. The proposed method has been tested and evaluated using real data that are collected during the winter of 2016–2017 in Suzu and Kanazawa, Japan. The experimental results show that the proposed method increases the robustness of autonomous driving on wet road surfaces, provides a stable performance in laterally localizing the vehicle in the presence of snow lines, and significantly reduces the overall localization error at a speed of 60 km/h.
Autors: Mohammad Aldibaja;Naoki Suganuma;Keisuke Yoneda;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2369 - 2378
Publisher: IEEE
 
» Robust LFM Target Detection in Wideband Sonar Systems
Abstract:
Linear frequency modulation (LFM) signals have been widely used for target detection in active sonar systems due to their robustness to reverberation. However, LFM active sonar requires a large number of reference signals for detecting targets moving with unknown speeds. To obtain more accurate detection results, more reference signals are required, resulting in an increased computational burden and memory size. To cope up with this problem, we propose a new fast target detection method that is robust to the variation of unknown target speed. A large number of reference signals come into a single reference signal by aligning them with precalculated time-shifts, which is followed by a summation process. Both narrowband and wideband cases are considered. The proposed method secures a signal-to-noise ratio (SNR), approaching that of the optimal matched filter output, that is also robust to the variation of target speed and thus it is very useful for the practical use in antitorpedo torpedoes or supercavitating underwater missiles that need to equip low-complexity and robust signal processing systems. Moreover, a rough Doppler estimation is presented using the proposed replica design method. Performance analyses show that the proposed method provides output SNR close to the optimal performance and that the computational load is extremely reduced as compared to the conventional LFM target detection method.
Autors: Dong-Hun Lee;Jong-Woo Shin;Dae-Won Do;Sang-Moon Choi;Hyoung-Nam Kim;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2399 - 2412
Publisher: IEEE
 
» Robust MMSE Transceiver Design for Nonregenerative Multicasting MIMO Relay Systems
Abstract:
In this paper, we investigate the transceiver design for nonregenerative multicasting multiple-input multiple-output (MIMO) relay systems, where one transmitter broadcasts common message to multiple receivers with the aid of a relay node. The transmitter, relay, and receivers are all equipped with multiple antennas. We assume that the true (unknown) channel matrices have Gaussian distribution, with the estimated channels as the mean value, and the channel estimation errors follow the well-known Kronecker model. We first develop an iterative robust algorithm to jointly design the transmitter, relay, and receiver matrices to minimize the maximal mean-squared error (MSE) of the signal waveform estimation among all receivers. Then, we derive the optimal structure of the relay precoding matrix and show that the MSE at each receiver can be decomposed into the sum of the MSEs of the first-hop and second-hop channels. Based on this MSE decomposition, we develop a simplified transceiver design algorithm with a low computational complexity. Numerical simulations demonstrate the improved robustness of the proposed transceiver design algorithms against the mismatch between the true and estimated channels. Interestingly, compared with the iterative algorithm, the simplified transceiver design has only negligible performance loss with significantly reduced computational complexity.
Autors: Lenin Gopal;Yue Rong;Zhuquan Zang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 8979 - 8989
Publisher: IEEE
 
» Robust Model Predictive Controller for Tracking Changing Periodic Signals
Abstract:
In this paper, we propose a novel robust model predictive controller for tracking periodic signals for linear systems subject to bounded additive uncertainties based on nominal predictions and constraint tightening. The proposed controller joins optimal periodic trajectory planning and robust control for tracking in a single optimization problem and guarantees that the perturbed closed-loop system converges asymptotically to a neighborhood of an optimal reachable periodic trajectory while robustly satisfying the constraints. In addition, the closed-loop system maintains recursive feasibility even in the presence of sudden changes in the target reference.
Autors: M. Pereira;D. Muñoz de la Peña;D. Limon;I. Alvarado;T. Alamo;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5343 - 5350
Publisher: IEEE
 
» Robust Noncooperative Spectrum Sharing Game in Underwater Acoustic Interference Channels
Abstract:
This paper focuses on underwater acoustic (UA) communications and proposes a decentralized spectrum sharing method for noncooperative orthogonal frequency-division multiplexing systems in interference channels. The problem is formulated as a noncooperative game where the players are UA communication systems aiming at finding the power allocation on subcarriers that maximizes a utility function related to their information rate. Realistic assumptions regarding the UA context are formulated. Frequency-selective and randomly time-varying channels are considered. Each system is constrained in average power and adapts its power allocation strategy only with local knowledge of its channel statistics and noise plus interference power spectral density. This knowledge is obtained through a feedback link from the receiver. Estimation errors on the channel statistics are taken into account, thanks to a robust reformulation of the game. We show that an efficient decentralized spectrum sharing can be achieved when all players use a water-filling strategy against each other iteratively. Simulations results are obtained on synthetic but realistic channels. In configurations where the UA communication systems are in close areas, significant increases of spectral efficiencies can be expected compared to the conventional uniform power allocation. Results on channels sounded at sea support our conclusions.
Autors: Antony Pottier;François-Xavier Socheleau;Christophe Laot;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 1019 - 1034
Publisher: IEEE
 
» Robust Pose Estimation for Multirotor UAVs Using Off-Board Monocular Vision
Abstract:
This paper deals with the problem of pose estimation (or motion estimation) for multirotor unmanned aerial vehicles (UAVs) by using only an off-board camera. An extended Kalman filter (EKF) is often adopted to solve this problem. However, the accuracy and robustness of an EKF are limited partly by the usage of an existing linear constant-velocity process model applicable to many rigid objects. For such a reason, a nonlinear constant-velocity process model featured with the characteristics of multirotor UAVs is proposed in this paper, the superiority of which is explained from the perspective of observability. With the new process model and a generic camera model, a practical EKF method suitable for conventional cameras and fish-eye cameras is then proposed. By taking EKF implementation into account, a general correspondence method that could handle any number of feature points is further designed. Simulation and real experiments show that the proposed EKF method is more robust against noise and occlusion than currently employed filtering methods.
Autors: Qiang Fu;Quan Quan;Kai-Yuan Cai;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7942 - 7951
Publisher: IEEE
 
» Robust Resource Allocation in Full-Duplex-Enabled OFDMA Femtocell Networks
Abstract:
In this paper, we study resource allocation for full-duplex communications in an orthogonal frequency division multiple access femtocell network. We aim to maximize the throughput of the femtocell while avoiding severe inter-tier interference to the macrocell via joint sub-channel assignment and power allocation. To be more practical, we take channel estimation error into account and use the robust optimization theory to model the uncertainty in interference channels. By using the Lagrangian dual method, we decompose the original optimization problem into a primal problem and a dual problem. We adopt the concave-convex procedure to transform the non-convex primal problem into a tractable form through sequential convex approximations and then utilize the sub-gradient method to solve the dual problem. Simulation results show the effectiveness of the proposed algorithm and demonstrate the impact of channel uncertainty on the system performance.
Autors: Sa Xiao;Xiangwei Zhou;Yi Yuan-Wu;Geoffrey Ye Li;Wei Guo;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6382 - 6394
Publisher: IEEE
 
» Robust Sonar ATR Through Bayesian Pose-Corrected Sparse Classification
Abstract:
Sonar imaging has seen vast improvements over the last few decades due in part to advances in synthetic aperture sonar. Sophisticated classification techniques can now be used in sonar automatic target recognition (ATR) to locate mines and other threatening objects. Among the most promising of these methods is sparse reconstruction-based classification (SRC), which has shown an impressive resiliency to noise, blur, and occlusion. We present a coherent strategy for expanding upon SRC for sonar ATR that retains SRC’s robustness while also being able to handle targets with diverse geometric arrangements, bothersome Rayleigh noise, and unavoidable background clutter. Our method, pose-corrected sparsity (PCS), incorporates a novel interpretation of a spike and slab probability distribution toward use as a Bayesian prior for class-specific discrimination in combination with a dictionary learning scheme for localized patch extractions. Additionally, PCS offers the potential for anomaly detection in order to avoid false identifications of tested objects from outside the training set with no additional training required. Compelling results are shown using a database provided by the U.S. Naval Surface Warfare Center.
Autors: John McKay;Vishal Monga;Raghu G. Raj;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5563 - 5576
Publisher: IEEE
 
» Robust Spatiotemporal LS-SVM Modeling for Nonlinear Distributed Parameter System With Disturbance
Abstract:
Most distributed parameter systems (DPS) have a strongly nonlinear spatiotemporal nature and are affected by disturbance. However, most of the existing DPS modeling methods only consider the linear relation between the spatial positions, but neglect the nonlinear one. Additionally, they also do not account for the influence of disturbance. Thus, in this paper, a robust spatiotemporal least squares support vector machine (LS-SVM) modeling method for DPS with disturbance is proposed. First, a spatial kernel function is constructed in order to describe the nonlinear relation between spatial positions. An optimal fusion method is then developed to derive a robust temporal coefficient, from which the influence of disturbance can be rejected. Through the integration of the spatial kernel function and the robust temporal coefficient, a robust spatiotemporal LS-SVM model is constructed. Since this modeling not only considers the nonlinear nature but also takes the influence of disturbance into account, it has the ability to adapt well to the nonlinear spatiotemporal dynamics, even when disturbance is presented. The analysis and proof show that the proposed robust spatiotemporal LS-SVM modeling method has the better robust performance as compared to the existing ones. Case studies not only demonstrate the effectiveness of the proposed method, but also demonstrate its superior robustness than other conventional modeling methods.
Autors: Xinjiang Lu;Wei Zou;Minghui Huang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 8003 - 8012
Publisher: IEEE
 
» Robust Visual Tracking via Collaborative Motion and Appearance Model
Abstract:
In this paper, robust visual tracking scheme is achieved through a novel sparse tracking via collaborative motion and appearance (TCMA). A coarse-to-fine framework with both motion and holistic appearance information is taken into consideration. In coarse search, we employ an optical flow map for the generation of motion particles. A rough estimation of target image patch is obtained using -regularized least square method in coarse search stage. In fine search, a novel smooth term is proposed in the cost function to improve the robustness of the tracker. With this smooth term, the object appearance in the previous frame will also affect the calculation of sparse coefficient in the current frame. It allows the tracker involving temporal information between consecutive frames instead of only considering single frame appearance information as in the conventional sparse coding-based tracking algorithms. In order to reserve the original and latest appearance information simultaneously in the template, a quadratic-function-like weight allocation scheme combining with particle contributed histogrammic correlation is developed in the updating stage. Both qualitative and quantitative studies are conducted on a set of challenging image sequences. The superior performance over other state-of-the-art algorithms is verified through the experiment.
Autors: Fangwen Tu;Shuzhi Sam Ge;Yazhe Tang;Chang Chieh Hang;
Appeared in: IEEE Transactions on Industrial Informatics
Publication date: Oct 2017, volume: 13, issue:5, pages: 2251 - 2259
Publisher: IEEE
 
» Robust Weighted Least Squares Method for TOA-Based Localization Under Mixed LOS/NLOS Conditions
Abstract:
In this letter, the time-of-arrival-based localization problem under mixed line-of-sight/non-line-of-sight conditions is addressed. Based on the a priori information of known path status, we propose a new robust weighted least squares (RWLS) method to improve the performance of the existing RWLS method, and the weights in the new RWLS problem are derived and explicitly given. The proposed RWLS problem is approximately solved by employing the second-order cone relaxation technique. Furthermore, when the path status is incorrectly identified, we propose a procedure of correcting the incorrect path status to make the RWLS method robust against the path status identification errors. The performance of the new RWLS method is verified by computer simulations.
Autors: Wei Wang;Gang Wang;Jie Zhang;Youming Li;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2226 - 2229
Publisher: IEEE
 
» Role of Elastic Scattering of Protons, Muons, and Electrons in Inducing Single-Event Upsets
Abstract:
The contribution of elastic scattering to single-event upset (SEU) by low-energy protons is usually considered negligible. This paper develops the formulas needed for calculating the cross section (CS) to create Si recoils of the elastic scattering of protons, muons, and electrons in silicon devices. The results are used to calculate SEU CS. This is compared with existing experimental results and with Monte Carlo calculations. For protons, the elastic scattering-induced SEU has a dominant role in sensitive devices at energies between about 2 and 10 MeV. The sum of this process with the inelastic scattering and direct ionization is in good agreement with experiments. For muons, the elastic SEU is significant at energies larger than 100 MeV. In the atmosphere, such muons have high flux. However, their elastic CS is small and the effect of the Si recoils is less important than that due to neutrons and protons in the atmosphere. For electrons, the elastic scattering starts to be significant at tens of MeV energies, as found experimentally. The expressions of elastic scattering were used for calculating the nuclear stopping power and the nonionizing energy loss (NIEL) of protons, muons, and electrons. The results are in agreement with published data.
Autors: Avraham Akkerman;Joseph Barak;Nir M. Yitzhak;
Appeared in: IEEE Transactions on Nuclear Science
Publication date: Oct 2017, volume: 64, issue:10, pages: 2648 - 2660
Publisher: IEEE
 
» ROSE: Robustness Strategy for Scale-Free Wireless Sensor Networks
Abstract:
Due to the recent proliferation of cyber-attacks, improving the robustness of wireless sensor networks (WSNs), so that they can withstand node failures has become a critical issue. Scale-free WSNs are important, because they tolerate random attacks very well; however, they can be vulnerable to malicious attacks, which particularly target certain important nodes. To address this shortcoming, this paper first presents a new modeling strategy to generate scale-free network topologies, which considers the constraints in WSNs, such as the communication range and the threshold on the maximum node degree. Then, ROSE, a novel robustness enhancing algorithm for scale-free WSNs, is proposed. Given a scale-free topology, ROSE exploits the position and degree information of nodes to rearrange the edges to resemble an onion-like structure, which has been proven to be robust against malicious attacks. Meanwhile, ROSE keeps the degree of each node in the topology unchanged such that the resulting topology remains scale-free. The extensive experimental results verify that our new modeling strategy indeed generates scale-free network topologies for WSNs, and ROSE can significantly improve the robustness of the network topologies generated by our modeling strategy. Moreover, we compare ROSE with two existing robustness enhancing algorithms, showing that ROSE outperforms both.
Autors: Tie Qiu;Aoyang Zhao;Feng Xia;Weisheng Si;Dapeng Oliver Wu;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 2944 - 2959
Publisher: IEEE
 
» Rotary Joint Perpendicularly Fed by a Substrate Integrated Waveguide Feeder
Abstract:
Two rotary joints perpendicularly fed by the substrate integrated waveguide (SIW) feeder are presented in this paper. The planar SIW feeder excites the circular waveguide with the desired rotational symmetric mode through a circular slot, whose effect can be modeled through a horizontal magnetic current on the top surface of the SIW. First, a single-layer SIW feeder is designed in the rotary joint with simple configuration. After that, a dual-layer SIW feeder is proposed to improve the performance of the single-layer version, especially for the bandwidth. Both of them have two controllable transmission poles, which can be used to optimize performance. After introducing the design principle and process, two rotary joints perpendicularly fed by different SIW feeders are fabricated and measured. For the dual-layer feeder rotary joint, it is able to operate from 11.1 to 12.4 GHz. Within an 11.1% relative bandwidth, its insertion loss is less than 1.21 dB and return loss is better than 10.85 dB when being rotated at different angles.
Autors: Zhi Jie Xuan;Yu Jian Cheng;
Appeared in: IEEE Transactions on Microwave Theory and Techniques
Publication date: Oct 2017, volume: 65, issue:10, pages: 3761 - 3768
Publisher: IEEE
 
» Rotational Energy Harvesting To Prolong Flight Duration of Quadcopters
Abstract:
This paper presents a rotational energy harvester using a brushless dc (BLdc) generator to harvest ambient energy for quadcopter in order to prolong it flight duration. For a quadcopter, its endurance is essential in order to achieve operational goals such as scientific research, security, surveillance, and reconnaissance. Because quadcopters have a limitation on size and mass, they cannot carry a large mass of on-board energy thereby having short flight time. In this paper, BLdc generators are coupled with the propellers of the quadcopter to transfer kinetic energy from the propellers to the generator. Taking into consideration the power requirement of quadcopter, the output of the generator is amplified using dc–dc boost, and is regulated to power and charge the on-board battery. The BLdc generator is simulated in MATLAB/Simulink. A final prototype of the rotational energy harvesting system is built, and this comprises a quadcopter, power management system, and a battery charging system.
Autors: Robert A. Sowah;Moses Amoasi Acquah;Abdul R. Ofoli;Godfrey A. Mills;Koudjo M. Koumadi;
Appeared in: IEEE Transactions on Industry Applications
Publication date: Oct 2017, volume: 53, issue:5, pages: 4965 - 4972
Publisher: IEEE
 
» Rotman Lens Based Hybrid Analog–Digital Beamforming in Massive MIMO Systems: Array Architectures, Beam Selection Algorithms and Experiments
Abstract:
Hybrid analog-digital beamforming is a well-known cost-efficient signal processing method for massive MIMO systems. In this paper, we propose a hybrid beamforming massive MIMO system based on Rotman lens analog beamforming with beam selection and digital beamforming. Rotman lens is a low-cost true-time-delay analog beamforming network supporting wide bandwidth signals, which is thus more attractive than the analog beamforming networks based on conventional high-cost phase shifters. To study our system based on Rotman lens, we first examine two potential array architectures, i.e., full-array and subarray architectures, concerning the RF design feasibility, insertion loss, and system scalability. Since the beam selection is required in our system, we propose two beam selection algorithms, i.e., greedy search-based method and branch- and bound-based method, aiming to optimize the hybrid beamforming system in terms of error-rate performance for both the full-array and subarray architectures. To validate our system in practice, the proposed system is also investigated and verified experimentally. In particular, we design and fabricate a sample of Rotman lens operating in the 5-GHz band, whose measured results agrees well with the computer simulation results. The measurement results are incorporated into the Monte-Carlo simulation with the proposed beam selection algorithms to study the error-rate performance. Our simulation results show that the hybrid beamforming system using the low-cost Rotman lens has performance comparable to that of the system using the high-cost phase shifters, and exhibits wideband capability and superior performance over the small-scale MIMO system under the same number of RF transceivers.
Autors: Yuan Gao;Maher Khaliel;Feng Zheng;Thomas Kaiser;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9134 - 9148
Publisher: IEEE
 
» Routing in Accumulative Multi-Hop Networks
Abstract:
This paper investigates the problem of finding optimal paths in single-source single-destination accumulative multi-hop networks. We consider a single source that communicates to a single destination assisted by several relays through multiple hops. At each hop, only one node transmits, while all the other nodes receive the transmitted signal, and store it after processing/decoding and mixing it with the signals received in previous hops. That is, we consider that terminals make use of advanced energy accumulation transmission/reception techniques, such as maximal ratio combining reception of repetition codes, or information accumulation with rateless codes. Accumulative techniques increase communication reliability, reduce energy consumption, and decrease latency. We investigate the properties that a routing metric must satisfy in these accumulative networks to guarantee that optimal paths can be computed with Dijkstra’s algorithm. We model the problem of routing in accumulative multi-hop networks, as the problem of routing in a hypergraph. We show that optimality properties in a traditional multi-hop network (monotonicity and isotonicity) are no longer useful and derive a new set of sufficient conditions for optimality. We illustrate these results by studying the minimum energy routing problem in static accumulative multi-hop networks for different forwarding strategies at relays.
Autors: Jesús Gómez-Vilardebó;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 2815 - 2828
Publisher: IEEE
 
» Row-by-Row Coding Schemes for Inter-Cell Interference in Flash Memory
Abstract:
Inter-cell interference (ICI) is a significant cause of errors in flash memories. In single-level cell (SLC) flash memory, ICI arises when 1 0 1 patterns are programmed either in the horizontal or vertical directions. Since data pages are written sequentially in horizontal wordlines, one can mitigate the effects of horizontal ICI by applying conventional constrained codes that forbid the 1 0 1 pattern. This approach does not address the problem of vertical ICI, however. In this paper, a row-by-row coding technique that eliminates vertical 1 0 1 patterns while preserving the sequential wordline programming order is presented. This scheme, though efficient, necessarily suffers a rate loss of almost 20%. We therefore propose another coding scheme, combining a weak constraint on vertical 1 0 1 patterns with a systematic error-correcting code, that can mitigate vertical ICI errors while achieving a higher overall coding rate, provided that the vertical ICI error probability is sufficiently small. Some extensions for multi-level cell (MLC) flash memory are discussed as well.
Autors: Sarit Buzaglo;Paul H. Siegel;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4101 - 4113
Publisher: IEEE
 
» Safe Guidance for a Walking-Assistant Robot Using Gait Estimation and Obstacle Avoidance
Abstract:
This paper presents a motion control design for a walking-assistant robot by combining passive-compliant behavior and active obstacle avoidance. The proposed method recognizes the intended motion for a user using gait movement and the applied force of a hand. A passive-compliant motion control is developed that allows the user to safely walk with the robot. The obstacle avoidance controller actively controls the velocity to guide the user in a direction that avoids collisions. A shared-control scheme combines active obstacle avoidance and passive-compliant motion commands. The experimental results verify the effectiveness of the proposed method and show that the robot allows a user to walk safely in a complex environment. A questionnaire survey of elderly users shows that the proposed design for a walking-assistant robot gives satisfactory performance.
Autors: Kai-Tai Song;Sin-Yi Jiang;Shang-Yang Wu;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Oct 2017, volume: 22, issue:5, pages: 2070 - 2078
Publisher: IEEE
 
» Safe, Efficient, and Robust SDN Updates by Combining Rule Replacements and Additions
Abstract:
Disruption-free updates are a key primitive to effectively operate SDN networks and maximize the benefits of their programmability. In this paper, we study how to implement this primitive safely (with respect to forwarding correctness and policies), efficiently (in terms of consumed network resources) and robustly to unpredictable factors, such as delayed message delivery and processing. First, we analyze the fundamental limitations of prior proposals, which either: 1) progressively replace initial flow rules with new ones or 2) instruct switches to maintain both initial and final rules. Second, we show that safe, efficient, and robust updates can be achieved by leveraging a more general approach. We indeed unveil a dualism between rule replacements and additions that opens new degrees of freedom for supporting SDN updates. Third, we demonstrate how to build upon this dualism. We propose FLIP, an algorithm that computes operational sequences combining the efficiency of rule replacements with the applicability of rule additions. FLIP identifies constraints on rule replacements and additions that independently prevent safety violations from occurring during the update. Then, it explores the solution space by swapping constraints that prevent the same safety violations, until it reaches a satisfiable set of constraints. Fourth, we perform extensive simulations, showing that FLIP can significantly outperform prior work. In the average case, it guarantees a much higher success rate than algorithms only based on rule replacements, and massively reduces the memory overhead needed by techniques solely using rule additions.
Autors: Stefano Vissicchio;Luca Cittadini;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 3102 - 3115
Publisher: IEEE
 
» SAR Ground Plane Mover Signatures for Nonzero Radar Ascent
Abstract:
Recent spotlight synthetic aperture radar analyses predict the two-dimensional range migration signature smears induced by targets with arbitrary motion in the ground plane. These investigations were limited to a constant-velocity radar motion with level flight path. The current correspondence removes this constraint by including the radar trajectory ascent angle.
Autors: David Alan Garren;
Appeared in: IEEE Transactions on Aerospace and Electronic Systems
Publication date: Oct 2017, volume: 53, issue:5, pages: 2214 - 2220
Publisher: IEEE
 
» Saturated Adaptive Control of an Electrohydraulic Actuator with Parametric Uncertainty and Load Disturbance
Abstract:
In this paper, a saturated adaptive control of an electrohydraulic actuator is proposed to drive the joint motion of a two-degree-of-freedom robotic arm. Due to the largely unknown load disturbance from the driven force/torque of the robotic arm and the existing control saturation of a servo valve, a Nussbaum function is designed to compromise between the antiwindup control effect and the dynamic response performance of an electrohydraulic system. Then, an adaptive parametric estimation law is designed to estimate the hydraulic parametric uncertainties. The effectiveness of the proposed controller has been demonstrated by comparative experimental study, which indicates that this controller can quickly recover the unsaturated dynamics with satisfactory tracking accuracy under largely unknown load disturbance and parametric uncertainty.
Autors: Qing Guo;Jingmin Yin;Tian Yu;Dan Jiang;
Appeared in: IEEE Transactions on Industrial Electronics
Publication date: Oct 2017, volume: 64, issue:10, pages: 7930 - 7941
Publisher: IEEE
 
» SCALA—A Scalable Rail-based Multirobot System for Large Space Automation: Design and Development
Abstract:
In this paper, a prototype of the SCAlable ModuLar (SCALA) multiagent robotic system is developed and implemented. This system for automation in large spaces relies on mobile agents that move on a planar and modular mesh of rails with embedded accurate positioning sensors. Groups of three mobile agents are joined together to drive a parallel manipulator, thus allowing fine manipulation tasks to be performed on a large workspace. The mechanical, mechatronics, and control solutions adopted on the prototype are reported and discussed, as well as its performance on the several tests performed.
Autors: Carlos Viegas;Mahmoud Tavakoli;Pedro Lopes;Ricardo Dessi;Aníbal T. de Almeida;
Appeared in: IEEE/ASME Transactions on Mechatronics
Publication date: Oct 2017, volume: 22, issue:5, pages: 2208 - 2217
Publisher: IEEE
 
» Scalable Fabrication of PEGDA Microneedles Using UV Exposure via a Rotating Prism
Abstract:
We propose a simple, fast, height-scalable, and direct way to fabricate highly biocompatible polyethylene glycol diacrylate (PEGDA) microneedles. A needle-shaped distribution of ultraviolet (UV) exposure dose is formed in PEGDA by applying UV light through a rotating prism. A prism makes UV light rays bend, such that the base angle of the prism determines the inclined angle of the light. Thus, the microneedle height can be controlled by varying the base angles of the prism. We experimentally demonstrate the direct height-scalable potential. The microneedle height decreases and the microneedle tip angle increases with increases in the base angle of the prism. These results indicate that the microneedle geometry can be easily controlled by the base angle of a prism without additional microfabrication. In addition, unlike photoresist microneedles, PEGDA does not require any thermal baking, thus enabling well-defined symmetric needle formation with short process time. Therefore, the present method can facilitate PEGDA microneedles to practical applications. [2017-0136]
Autors: H. Takahashi;Y. J. Heo;I. Shimoyama;
Appeared in: Journal of Microelectromechanical Systems
Publication date: Oct 2017, volume: 26, issue:5, pages: 990 - 992
Publisher: IEEE
 
» Scalable Multicast in Highly-Directional 60-GHz WLANs
Abstract:
The 60-GHz bands target multi-gigabit rate applications, such as high definition video streaming. Unfortunately, to provide multicast service, the strong directionality required at 60 GHz precludes serving all clients in a multicast group with a single transmission. Instead, a multicast transmission is comprised of a sequence of beam-formed transmissions (a beam group) that together cover all multicast group members. In this paper, we design, implement, and experimentally evaluate scalable directional multicast (SDM) as a technique to 1) train the access point with per-beam per-client RSSI measurements via partially traversing a codebook tree. The training balances the objectives of limiting overhead with collecting sufficient data to form efficient beam groups. 2) Using the available training information, we design a scalable beam grouping algorithm that approximates the minimum multicast group data transmission time. We implement the key components of SDM and evaluate with a combination of over-the-air experiments and trace-driven simulations. Our results show that the gains provided by SDM increase with group size and provide near-optimal group selection with significantly reduced training time, yielding up to 1.8 times throughput gains over exhaustive-search training and grouping.
Autors: Sharan Naribole;Edward Knightly;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 2844 - 2857
Publisher: IEEE
 
» Scalable Source Transmission With Unequal Frequency Reuse in MIMO Cellular Networks
Abstract:
This paper studies the optimal frequency reuse for the transmission of multimedia scalable sources, such as embedded images or scalable video, which need unequal error protection or unequal transmission rates in the bitstream. First, we analyze the crossover of the outage probabilities for full and partial frequency reuse cases in terms of the data rate. We prove that we can find a crossover of the outage probability curves for a data rate lower than a given threshold, which is a function of the parameters such as the partial frequency reuse factor and the user location in the cell. Moreover, the crossover point in the signal-to-noise ratio (SNR) is a strictly increasing function of the data rate. On the other hand, for a data rate higher than or equal to the threshold, there is no crossover; for all SNRs, the outage probability of full-frequency reuse is lower than that of partial-frequency reuse. The results are proven for the arbitrary location of a user in a cell, and for an arbitrary partial frequency reuse factor. Furthermore, the results hold, regardless of the numbers of transmit and receive antennas in the multiple-input multiple-output systems of orthogonal space-time block codes, and of the vertical Bell Labs space-time architecture with a zero-forcing linear receiver. Based on the analysis, we propose unequal-frequency reuse for the optimal transmission of scalable sources. The numerical results show that the peak-SNR performance improves when a sequence of scalable packets is transmitted at the subbands governed by unequal-frequency reuse in cellular networks.
Autors: Seok-Ho Chang;Hee-Gul Park;Jun Won Choi;Jihwan P. Choi;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4188 - 4204
Publisher: IEEE
 
» Scalable Verification of Networks With Packet Transformers Using Atomic Predicates
Abstract:
Packet transformers are widely used in ISPs, datacenter infrastructures, and layer-2 networks. Existing network verification tools do not scale to large networks with transformers (e.g., MPLS, IP-in-IP, and NAT). Toward scalable verification, we conceived a novel packet equivalence relation. For networks with packet transformers, we first present a formal definition of the packet equivalence relation. Our transformer model is general, including most transformers used in real networks. We also present a new definition of atomic predicates that specify the coarsest equivalence classes of packets in the packet space. We designed an algorithm for computing these atomic predicates. We built a verifier, named Atomic Predicates for Transformers, and evaluated its performance using four network data sets with MPLS tunnels, IP-in-IP tunnels, and NATs. For a provider cone data set with 11.6 million forwarding rules, 92 routers, 1920 duplex ports, and 40 MPLS tunnels which use 170 transformers, APT used only 0.065 s, on average, to compute the reachability tree from a source port to all other ports for all packets and perform loop detection as well. For the Stanford and Internet2 data sets with NATs, APT is faster than HSA (Hassel in C implementation) by two to three orders of magnitude. By working with atomic predicates instead of individual packets, APT achieves verification performance gains by orders of magnitude.
Autors: Hongkun Yang;Simon S. Lam;
Appeared in: IEEE/ACM Transactions on Networking
Publication date: Oct 2017, volume: 25, issue:5, pages: 2900 - 2915
Publisher: IEEE
 
» ScAlN-Based LCAT Mode Resonators Above 2 GHz With High FOM and Reduced Fabrication Complexity
Abstract:
This letter reports the first implementation of a new class of laterally coupled alternating thickness (LCAT) mode resonators operating above 2 GHz, realised by replacing the bottom interdigitated electrodes of the conventional LCAT mode resonator with an electrically floating plate. Besides saving one mask process and relaxing the tight resolution and alignment requirements for defining small features, the flat unpatterned bottom electrode metal is also more favorable for the growth of highly oriented piezoelectric thin film, which results in an improved resonator quality factor (). A group of 8% scandium doped aluminium nitride-based modified LCAT mode resonators with frequency difference over 100 MHz by varying the top interdigitated electrode pitches are fabricated achieving coupling coefficient ( of up to 6.45% and figure of merit of up to 54, making them promising candidates for integrated band selection filter banks.
Autors: Yao Zhu;Nan Wang;Gengli Chua;Chengliang Sun;Navab Singh;Yuandong Gu;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1481 - 1484
Publisher: IEEE
 
» Scanning the Issue
Abstract:
Overview of Environment Perception for Intelligent Vehicles H. Zhu, K.-V. Yuen, L. Mihaylova, and H. Leung A comprehensive literature review on environment perception for intelligent vehicles is presented. The state-of-the-art algorithms and modeling methods for intelligent vehicles are given, with a summary of their pros and cons. Special attention is paid to methods for lane and road detection, traffic sign recognition, vehicle tracking, behavior analysis, and scene understanding. In addition, the authors provide information about data sets, common performance analysis, and perspectives on future research directions in this area.
Autors: Petros Ioannou;A. V. Bal Balakrishnan;
Appeared in: IEEE Transactions on Intelligent Transportation Systems
Publication date: Oct 2017, volume: 18, issue:10, pages: 2581 - 2583
Publisher: IEEE
 
» Scatterer Localization Using Large-Scale Antenna Arrays Based on a Spherical Wave-Front Parametric Model
Abstract:
In this contribution, an algorithm based on the space-alternating generalized expectation–maximization principle is proposed for estimating the locations of scatterers involved in the last-hops of propagation paths when a large-scale antenna array is used in a receiver for channel measurement. The underlying generic parametric model is constructed under the spherical wave-front assumption, which allows characterizing a path with a new parameter, i.e., the distance between the scatterer at the last-hop of the path and a specific receiving antenna, additional to the conventional parameters characterizing a specular path under the plane wave-front assumption. Cramér–Rao lower bounds of mean squared errors are derived for the parameter estimators in a single-path scenario, and their accuracy is evaluated through Monte Carlo simulations. The performance of the algorithm when being applied in reality is also evaluated through experiments conducted in an office with a carrier frequency of 9.5 GHz, a bandwidth of 500 MHz, and the receiver equipped with a 121-element virtual array. The proposed signal model and algorithm can be extended to the case of localizing the scatterers in the first- and last-hops of paths when large-scale antenna arrays are used in both the transmitter and the receiver.
Autors: Xuefeng Yin;Stephen Wang;Nan Zhang;Bo Ai;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6543 - 6556
Publisher: IEEE
 
» Scene Classification Based on the Fully Sparse Semantic Topic Model
Abstract:
In high spatial resolution (HSR) imagery scene classification, it is a challenging task to recognize the high-level semantics from a large volume of complex HSR images. The probabilistic topic model (PTM), which focuses on modeling topics, has been proposed to bridge the so-called semantic gap. Conventional PTMs usually model the images with a dense semantic representation and, in general, one topic space is generated for all the different features. However, this approach fails to consider the sparsity of the semantic representation, the classification quality, as well as the time consumption. In this paper, to solve the above problems, a fully sparse semantic topic model (FSSTM) framework is proposed for HSR imagery scene classification. FSSTM, with an elaborately designed modeling procedure, is able to represent the image with sparse but representative semantics. Based on this framework, the topic weights of multiple features are exploited by solving a concave maximization problem, which improves the fusion of the discriminative semantic information at the topic level. Meanwhile, the sparsity and representativeness of the topics generated by FSSTM guarantee that the image is adaptive to the change of a topic number. FSSTM can consistently achieve a good performance with a limited number of training samples, and is robust for HSR image scene classification. The experimental results obtained with three different types of HSR image data sets confirm that the proposed algorithm is effective in improving the performance of scene classification, and is highly efficient in discovering the semantics of HSR images when compared with the state-of-the-art PTM methods.
Autors: Qiqi Zhu;Yanfei Zhong;Liangpei Zhang;Deren Li;
Appeared in: IEEE Transactions on Geoscience and Remote Sensing
Publication date: Oct 2017, volume: 55, issue:10, pages: 5525 - 5538
Publisher: IEEE
 
» Schottky-MOS Hybrid Anode AlGaN/GaN Lateral Field-Effect Rectifier With Low Onset Voltage and Improved Breakdown Voltage
Abstract:
For devices with a 15 micron anode-to-cathode distance, nearly 1.5 times increase in the blocking (breakdown) voltage (from 692 to 1030 V) has been achieved by replacing the alloyed Ohmic contact at the anode electrode of the conventional MOS gated hybrid-anode lateral field-effect rectifier (CMLFER) with a low barrier Schottky contact. The new Schottky-MOS hybrid-anode lateral field-effect rectifier is found to offer comparable low onset voltage ( of 0.68±0.13 versus 0.65±0.11 V for CMLFER) independent of the anode-to- cathode distance. The immunity of the punch through caused by drain induced barrier lowering effect is obtained through the low barrier Schottky contact in anode, which is believed to be responsible for the reduction in the leakage current, and the improvement of rectifier breakdown voltage.
Autors: Jingnan Gao;Maojun Wang;Ruiyuan Yin;Shaofei Liu;Cheng P. Wen;Jinyan Wang;Wengang Wu;Yilong Hao;Yufeng Jin;Bo Shen;
Appeared in: IEEE Electron Device Letters
Publication date: Oct 2017, volume: 38, issue:10, pages: 1425 - 1428
Publisher: IEEE
 
» Scientific Workflow Mining in Clouds
Abstract:
Computing clouds have become the platform of choice for the deployment and execution of scientific workflows. Due to the uncertainty and unpredictability of scientific exploration, the execution plan for a scientific workflow may vary from the definition. It is therefore of great significance to be able to discover actual workflows from execution histories (event logs) to reproduce experimental results and to establish provenance. However, most existing process mining techniques focus on discovering control flow-oriented business processes in a centralized environment, and thus, they are mostly inapplicable to the discovery of data flow-oriented, unstructured scientific workflows in distributed cloud environments. In this paper, we present Scientific Workflow Mining as a Service () to support both intra-cloud and inter-cloud scientific workflow mining. The approach is implemented as a plug-in and is evaluated on event logs derived from real-world scientific workflows. Through experimental results, we demonstrate the effectiveness and efficiency of our approach.
Autors: Wei Song;Fangfei Chen;Hans-Arno Jacobsen;Xiaoxu Xia;Chunyang Ye;Xiaoxing Ma;
Appeared in: IEEE Transactions on Parallel and Distributed Systems
Publication date: Oct 2017, volume: 28, issue:10, pages: 2979 - 2992
Publisher: IEEE
 
» SDNHAS: An SDN-Enabled Architecture to Optimize QoE in HTTP Adaptive Streaming
Abstract:
HTTP adaptive streaming (HAS) is receiving much attention from both industry and academia as it has become the de facto approach to stream media content over the Internet. Recently, we proposed a streaming architecture called SDNDASH [1] to address HAS scalability issues including video instability, quality of experience (QoE) unfairness, and network resource underutilization, while maximizing per player QoE. While SDNDASH was a significant step forward, there were three unresolved limitations: 1) it did not scale well when the number of HAS players increased; 2) it generated communication overhead; and 3) it did not address client heterogeneity. These limitations could result in suboptimal decisions that led to viewer dissatisfaction. To that effect, we propose an enhanced intelligent streaming architecture, called SDNHAS, which leverages software defined networking (SDN) capabilities of assisting HAS players in making better adaptation decisions. This architecture accommodates large-scale deployments through a cluster-based mechanism, reduces communication overhead between the HAS players and SDN core, and allocates the network resources effectively in the presence of short- and long-term changes in the network.
Autors: Abdelhak Bentaleb;Ali C. Begen;Roger Zimmermann;Saad Harous;
Appeared in: IEEE Transactions on Multimedia
Publication date: Oct 2017, volume: 19, issue:10, pages: 2136 - 2151
Publisher: IEEE
 
» Seabed Characterization From Ambient Noise Using Short Arrays and Autonomous Vehicles
Abstract:
Reliable SONAR-performance prediction in shallow water requires knowledge of the seabed reflectivity, or its geoacoustic properties, which is expensive and difficult to acquire in situ. This paper illustrates two sea trials conducted in different shallow water areas to investigate the feasibility of acquiring such knowledge efficiently from measurements of naturally occurring ambient noise by an array that is compact enough to be mounted on a small autonomous underwater vehicle. The system relies on a previous technique for passively estimating the bottom reflection loss from the acoustic noise field generated by wind and breaking waves at the sea surface. Results from these experiments supported by numerical modeling are presented and compared with independent measurements of the relevant seabed reflectivity properties. The results obtained from both experiments demonstrate the potential of using autonomous underwater vehicles for seabed characterization.
Autors: Peter Louring Nielsen;Lanfranco Muzi;Martin Siderius;
Appeared in: IEEE Journal of Oceanic Engineering
Publication date: Oct 2017, volume: 42, issue:4, pages: 1094 - 1101
Publisher: IEEE
 
» Sealing of Immersion Deuterium Dioxide and Its Application to Signal Maintenance for Ex-Vivo and In-Vivo Multiphoton Microscopy Excited at the 1700-nm Window
Abstract:
Excitation at the 1700-nm window is an effective means for extending imaging depth and imaging modalities in multiphoton microscopy (MPM). To enhance multiphoton signal levels and enable deep-tissue penetration, water immersion has to be replaced by deuterium dioxide (D2O) immersion to boost transmittance at the 1700-nm window. The key problem facing this D2O immersion technique is the hygroscopic nature of D2O, which leads to decrease of MPM signals as time lapses. Here, we demonstrate a simple, yet very effective technique to isolate D2 O from the ambient environment, by sealing it with the paraffin liquid. We demonstrate the application of this technique to MPM signal maintenance in both three-photon fluorescence generation in a fluorescent dye and third-harmonic generation (THG) imaging of biological tissue, excited at the 1700-nm window. Ex-vivo imaging results show that during an imaging session of 5 h, multiphoton signals of both modalities can be maintained with no deterioration due to absorption of water vapor from the environment. Furthermore, we demonstrate in-vivo deep-tissue mouse brain imaging using this technique, in which THG signals can be maintained for at least 5 h. This justifies the applicability and effectiveness of our D2O sealing technique for long-span in-vivo imaging.
Autors: Hongji Liu;Yu Du;Xiao Peng;Xuechang Zhou;Ping Qiu;Ke Wang;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 8
Publisher: IEEE
 
» Second-Order Nonlocal Effects Mitigation in Brillouin Optical Time-Domain Analysis Sensors by Tracking the Brillouin Frequency Shift Profile of the Fiber
Abstract:
We report on an additional limitation that has been found in Brillouin optical time-domain analysis (BOTDA) sensors due to the so-called second-order nonlocal effects (NLE). Second-order NLE appear in BOTDA setups that deploy a double probe waves to compensate the transfer of energy between the pump pulse and the probe wave, and are related to a spectral distortion of the pump pulse that leads to measurement errors and an effective limit on the maximum probe power that can be deployed in the sensor. We theoretically and experimentally demonstrate that the techniques that have been presented so far in the literature to compensate second-order NLE are only effective in the case that the Brillouin frequency shift (BFS) along the sensing fiber is uniform. However, this requirement for uniformity is not realistic in real world scenarios in which a variety of fibers with different BFS and subjected to different environmental conditions are typically deployed. Therefore, we demonstrate a new method to mitigate the effects of BFS variation in the BOTDA setups that compensate second-order NLE. This method is based on introducing an additional wavelength modulation to the probe wave so as to track the mean BFS changes along the sensing fiber link. With this method, we demonstrate a BOTDA setup that, without coding, distributed amplification, or any other form of performance enhancement, achieves a sensing length of 120 km with 3-m spatial resolution and 2-MHz measurement precision. Moreover, the setup demonstrates, to our knowledge, the largest probe power ever injected in a BOTDA sensing link.
Autors: Juan José Mompó;Haritz Iribas;Javier Urricelqui;Alayn Loayssa;
Appeared in: IEEE Photonics Journal
Publication date: Oct 2017, volume: 9, issue:5, pages: 1 - 12
Publisher: IEEE
 
» Second-Order Switching Time Optimization for Switched Dynamical Systems
Abstract:
Switching time optimization arises in finite-horizon optimal control for switched systems where, given a sequence of continuous dynamics, one minimizes a cost function with respect to the switching times. We propose an efficient method for computing the optimal switching times for switched linear and nonlinear systems. A novel second-order optimization algorithm is introduced where, at each iteration, the dynamics are linearized over an underlying time grid to compute the cost function, the gradient, and the Hessian efficiently. With the proposed method, the most expensive operations at each iteration are shared between the cost function and its derivatives, thereby greatly reducing the computational burden. We have implemented the algorithm in the Julia package SwitchTimeOpt, allowing users to easily solve switching time optimization problems. In the case of linear dynamics, many operations can be further simplified and benchmarks show that our approach is able to provide optimal solutions in just a few millisecond. In the case of nonlinear dynamics, our method provides optimal solutions with up to two orders of magnitude time reductions over state-of-the-art approaches.
Autors: Bartolomeo Stellato;Sina Ober-Blöbaum;Paul J. Goulart;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 5407 - 5414
Publisher: IEEE
 
» SecRBAC: Secure data in the Clouds
Abstract:
Most current security solutions are based on perimeter security. However, Cloud computing breaks the organization perimeters. When data resides in the Cloud, they reside outside the organizational bounds. This leads users to a loos of control over their data and raises reasonable security concerns that slow down the adoption of Cloud computing. Is the Cloud service provider accessing the data? Is it legitimately applying the access control policy defined by the user? This paper presents a data-centric access control solution with enriched role-based expressiveness in which security is focused on protecting user data regardless the Cloud service provider that holds it. Novel identity-based and proxy re-encryption techniques are used to protect the authorization model. Data is encrypted and authorization rules are cryptographically protected to preserve user data against the service provider access or misbehavior. The authorization model provides high expressiveness with role hierarchy and resource hierarchy support. The solution takes advantage of the logic formalism provided by Semantic Web technologies, which enables advanced rule management like semantic conflict detection. A proof of concept implementation has been developed and a working prototypical deployment of the proposal has been integrated within Google services.
Autors: Juan M. Marín Pérez;Gregorio Martínez Pérez;Antonio F. Skarmeta Gomez;
Appeared in: IEEE Transactions on Services Computing
Publication date: Oct 2017, volume: 10, issue:5, pages: 726 - 740
Publisher: IEEE
 
» Secrecy in MIMO Networks With No Eavesdropper CSIT
Abstract:
We consider two fundamental multi-user channel models: the multiple-input multiple-output (MIMO) wiretap channel with one helper (WTH) and the MIMO multiple access wiretap (MAC-WT) channel. In each case, the eavesdropper has antennas while the remaining terminals have antennas each. We consider a fast fading channel where the channel state information (CSI) of the legitimate receiver is available at the transmitters but no CSI at the transmitters (CSIT) is available for the eavesdropper’s channel. We determine the optimal sum secure degrees of freedom (s.d.o.f.) for each channel model for the regime , and show that in this regime, the MAC-WT channel reduces to the WTH in the absence of eavesdropper CSIT. For the regime , we obtain the optimal linear s.d.o.f., and show that the MAC-WT channel and the WTH have the same optimal s.d.o.f. when restricted to linear encoding strategies. In the absence of any such restrictions, we provide an upper bound for the sum s.d.o.f. of the MAC-WT channel in the regime . Our results show that unlike in the single-input single-output case, there is loss of s.d.o.f. for even the WTH due to lack of eavesdropper CSIT when .
Autors: Pritam Mukherjee;Sennur Ulukus;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4382 - 4391
Publisher: IEEE
 
» Secrecy Outage Analysis of $k$ th Best Link in Random Wireless Networks
Abstract:
In this paper, we analyze the secrecy characteristics of random wireless networks using stochastic geometric tools. The locations of the source and eavesdropper nodes are modeled as independent 2-D Poisson point processes. We investigate the secrecy outage probability of such networks from the perspective of the th best source, which has still not been well characterized. In particular, we derive the received path gain distributions of the typical destination and the eavesdropper from the th best source. Furthermore, we introduce a novel concept of security-region based on the th best source index. This is pragmatic in creating a protected communication zone for the typical destination and also to bind the number of sources that can coordinate in a coordinated multi-point transmission (CoMP) network. We further derive the secrecy outage probability for these CoMP sources based on the security-region. We also provide a closed-form expression for the maximum number of eavesdroppers for a given secrecy outage constraint, which can effect the secure communication. Tractable numerical, and simulation results are presented under various assumptions of densities, path loss exponents, and antenna figures.
Autors: Satyanarayana Vuppala;Sudip Biswas;Tharmalingam Ratnarajah;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4478 - 4491
Publisher: IEEE
 
» Secrecy Performance of an Idle Receiver Assisted Underlay Secondary Network
Abstract:
In this letter, we derive an expression for the secrecy outage probability of a multiuser underlay downlink in which a selected idle secondary user serves as a friendly jammer to enhance physical-layer secrecy of secondary downlink communication in the presence of a passive eavesdropper. Secondary nodes constrain their transmit powers to ensure that the interference caused to the primary network is below an interference temperature limit . We show that careful apportioning of between the secondary source and the selected jammer (which transmit simultaneously), and judicious choice of peak powers, is the key to improving secrecy performance. Computer simulation results demonstrate accuracy of the derived expressions.
Autors: Pratik Chakraborty;Shankar Prakriya;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9555 - 9560
Publisher: IEEE
 
» Secure Hybrid VLC-RF Systems With Light Energy Harvesting
Abstract:
In this paper, a hybrid visible light communication-radio frequency (RF) system, including a legitimate receiver (R) and an eavesdropper (E) is considered. R can harvest energy from the light emitted by light emitting diodes (LEDs), which is used for the information transmission between R and the RF receiver which is close to the LED. It is assumed that E tries to eavesdrop the information delivered from R to the RF receiver and R is with finite energy storage. Considering the randomness of the locations of R and E, the statistical characteristics of the received signal-to-noise ratio at the RF receiver and E are characterized; then, we derive the analytical expressions for exact and asymptotic secrecy outage probability by using the stochastic geometry method. Finally, simulations are carried out to verify our proposed analytical models.
Autors: Gaofeng Pan;Jia Ye;Zhiguo Ding;
Appeared in: IEEE Transactions on Communications
Publication date: Oct 2017, volume: 65, issue:10, pages: 4348 - 4359
Publisher: IEEE
 
» Secure Multiple-Antenna Block-Fading Wiretap Channels With Limited CSI Feedback
Abstract:
In this paper, we investigate the ergodic secrecy capacity of a block-fading wiretap channel with limited channel knowledge at the transmitter. We consider that the legitimate receiver, the eavesdropper, and the transmitter are equipped with multiple antennas and that the receiving nodes are aware of their respective channel matrices. On the other hand, the transmitter is only provided by a -bit feedback of the main channel state information. The feedback bits are sent by the legitimate receiver, at the beginning of each fading block, over an error-free public link with limited capacity. The statistics of the main and the eavesdropper channel state information are known at all nodes. Assuming an average transmit power constraint, we establish upper and lower bounds on the ergodic secrecy capacity. Then, we present a framework to design the optimal codebooks for feedback and transmission. In addition, we show that the proposed lower and upper bounds coincide asymptotically, as the capacity of the feedback link becomes large, i.e., , hence fully characterizing the ergodic secrecy capacity in this case. Besides, we analyze the asymptotic behavior of the presented secrecy rates, at high signal-to-noise ratio, and evaluate the gap between the bounds.
Autors: Amal Hyadi;Zouheir Rezki;Mohamed-Slim Alouini;
Appeared in: IEEE Transactions on Wireless Communications
Publication date: Oct 2017, volume: 16, issue:10, pages: 6618 - 6634
Publisher: IEEE
 
» Secure On–Off Transmission in Slow Fading Wiretap Channel With Imperfect CSI
Abstract:
This paper investigates the slow fading single-antenna wiretap channel with imperfect channel state information (CSI) and studies an on–off transmission scheme with fixed communication rate, secrecy rate, and transmit power for maximizing the secrecy throughput under the constraints of secrecy outage probability (SOP) and reliability outage probability (ROP). We first solve this problem in a special case without ROP constraint for which the optimal secrecy throughput is obtained under SOP constraint. The result for the special case gives us an upper bound for the secrecy throughput with imperfect CSI. With the help of this special case, a general case with ROP constraint is studied. In this case, the problem is transformed into a one-dimensional (1-D) search problem on a finite interval, which can be solved either by the exhaustive 1-D search to obtain the optimal solution or by the golden search method (GSM) to obtain a suboptimal solution. Simulation results are finally presented to validate the theoretical analysis and show that the performance obtained by using the GSM based 1-D search is very close to that of exhaustive 1-D search.
Autors: Pengcheng Mu;Zongze Li;Bo Wang;
Appeared in: IEEE Transactions on Vehicular Technology
Publication date: Oct 2017, volume: 66, issue:10, pages: 9582 - 9586
Publisher: IEEE
 
» Secure Polar Coding With REP and XOR Coding
Abstract:
In this letter, we study the secure data communication by polar coding. In polar coding, all bit-channels perfectly polarize when the codelength goes to infinity. With finite and practical codelength, however, many bit-channels do not perfectly polarize and this significantly degrades the secrecy rate. To address this issue, we propose to use repetition (REP) coding and exclusive-or (XOR) coding combined with polar coding. To make the proposed approach practical, we develop simple design methods for REP and XOR codings. Numerical results demonstrate that the proposed secure polar coding improves the secrecy rate and security gap considerably.
Autors: Il-Min Kim;Byoung-Hoon Kim;Joon Kui Ahn;
Appeared in: IEEE Communications Letters
Publication date: Oct 2017, volume: 21, issue:10, pages: 2126 - 2129
Publisher: IEEE
 
» Secure State Estimation for Cyber-Physical Systems Under Sensor Attacks: A Satisfiability Modulo Theory Approach
Abstract:
Secure state estimation is the problem of estimating the state of a dynamical system from a set of noisy and adversarially corrupted measurements. Intrinsically a combinatorial problem, secure state estimation has been traditionally addressed either by brute force search, suffering from scalability issues, or via convex relaxations, using algorithms that can terminate in polynomial time but are not necessarily sound. In this paper, we present a novel algorithm that uses a satisfiability modulo theory approach to harness the complexity of secure state estimation. We leverage results from formal methods over real numbers to provide guarantees on the soundness and completeness of our algorithm. Moreover, we discuss its scalability properties, by providing upper bounds on the runtime performance. Numerical simulations support our arguments by showing an order of magnitude decrease in execution time with respect to alternative techniques. Finally, the effectiveness of the proposed algorithm is demonstrated by applying it to the problem of controlling an unmanned ground vehicle.
Autors: Yasser Shoukry;Pierluigi Nuzzo;Alberto Puggelli;Alberto L. Sangiovanni-Vincentelli;Sanjit A. Seshia;Paulo Tabuada;
Appeared in: IEEE Transactions on Automatic Control
Publication date: Oct 2017, volume: 62, issue:10, pages: 4917 - 4932
Publisher: IEEE
 
» Security Analysis of Password-Authenticated Key Retrieval
Abstract:
A PAKR (Password-Authenticated Key Retrieval) protocol and its multi-server system allow one party (say, client), who has a memorable password, to retrieve a long-term static key in an exchange of messages with at least one other party (say, server) that has a private key associated with the password. In this paper, we analyze the only PAKR (named as PKRS-1) standardized in IEEE 1363.2 [9] and its multi-server system (also, [12]) by showing that any passive/ active attacker can find out the client's password and the static key with off-line dictionary attacks. This result contradicts the security claims made for PKRS-1 (see Clause 10.2 of IEEE 1363.2 [9]).
Autors: SeongHan Shin;Kazukuni Kobara;
Appeared in: IEEE Transactions on Dependable and Secure Computing
Publication date: Oct 2017, volume: 14, issue:5, pages: 573 - 576
Publisher: IEEE
 
» Seeing Beyond Foreground Occlusion: A Joint Framework for SAP-Based Scene Depth and Appearance Reconstruction
Abstract:
Foreground occlusion is a significant challenge in three-dimensional (3-D) reconstruction. In this paper, we first characterize the differences between multiview reconstruction with and without foreground occlusion. In order to reconstruct target scene, we attempt to see through the foreground occlusion using synthetic aperture photography. Different from existing methods, we propose a more generalized model for scene reconstruction, in which the target scene may not be fully observed by any of reference view. Assuming both scene depth and appearance are unknown, we reconstruct 3-D scene from camera array data by selecting optimal views with pixel based clustering. Then, we propose an iterative reconstruction approach in global optimization framework, in which we refine the reconstruction results by applying a coarse-to-fine strategy. Even when all views are partially occluded, our approach can recover accurate depth map as well as scene appearance using camera array data. Experimental results have indicated that the proposed approach is more robust to foreground occlusions and outperforms state-of-the-art approaches.
Autors: Zhaolin Xiao;Lipeng Si;Guoqing Zhou;
Appeared in: IEEE Journal of Selected Topics in Signal Processing
Publication date: Oct 2017, volume: 11, issue:7, pages: 979 - 991
Publisher: IEEE
 

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