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IEEE International Conference on Communications Workshops

作者： Shaohe Lv Weihua Zhuang Xiaodong Wang Xingming Zhou National Laboratory of Parallel and Distributed Processing National University of Defense Technology Department of Electrical and Computer Engineering University of Waterloo

ISBN: (纸本)9781612842325

We consider the greedy scheduling based on the physical model in wireless networks with successive interference cancellation (SIC). There are two major stages in a scheduling scheme, link selection (to decide which link is scheduled next) and time slot selection (to deciding which slot is allocated to a given link). Most available schemes take a first-fit policy in the latter and strive to achieve good performance by careful selection of link ordering with respect to interference. Due to the accumulation effect and sequential detection nature of SIC, however, it is difficult to evaluate the interference of a link. As a result, many existing scheduling schemes become less efficient. In this paper, we take a new look on the problem and focus to the time slot selection stage. We define tolerance margin to measure the saturation of a link set and present two heuristic policies: one is to schedule a link to a slot such that the resulting set of links has a maximum tolerance margin;the other is to choose a slot such that the increase of tolerance margin is minimum. Simulation results show that the performance of the proposed schemes is better than the first-fit policy and is close to the optimal solution.

关键词： Link scheduling Successive interference cancellation Physical interference model

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The texture classification using the fusion of decisions from different texture classifiers

The texture classification using the fusion of decisions fro...

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International Conference on electrical engineering/Electronics, computer, Telecommunications and Information Technology

作者： Pharsook, S. Kasetkasem, T. Larmsrichan, P. Siddhichai, S. Chanwimaluang, T. Isshiki, T. Department of Electrical Engineering Kasetsart University Thailand Image Processing Laboratory National Electronics and Computer Technology Center Thailand Department of Communication and Integrated Systems Tokyo Institue of Technology Japan

ISBN: (纸本)9781457704246

The improved of texture classification accuracy by using the probability weighted combination method of three texture features extraction consist of thE0020 Gray-Level Co-occurrence Matrix (GLCM), Semivariogram Function and Gaussian Markov Random Fields (GMRFs). Five different textures images are used in the experiment. The classifier that use for classify the extracted features in this research is Support Vector Machines (SVMs). The experimental result shows that the average accuracy of the combination method with probability weight up to 95.71%, which is better than the simple combination method about 2%. © 2011 IEEE.

关键词： Support vector machines

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A QoS-provision multi-channel MAC in RSU-assisted vehicular networks (poster)

A QoS-provision multi-channel MAC in RSU-assisted vehicular ...

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2011 IEEE Vehicular Networking Conference, VNC 2011

作者： Cheng, Nan Lu, Ning Wang, Ping Wang, Xinhong Liu, Fuqiang Dept. of Electronics and Information Engineering Tongji University Shanghai China Shanghai Key Laboratory of Digital Media Processing and Transmission Shanghai China Department of Electrical and Computer Engineering University of Waterloo Waterloo ON Canada

ISBN: (纸本)9781467300476

RSU-assisted VANETs should provide vehicles and mobile users with reliable safety applications as well as various non-safety services with different QoS levels. We present a dedicated multi-channel MAC plus a QoS-provision channel allocation scheme based on the EDCA channel throughput analysis to improve the QoS performance of non-safety services for the RSU-assisted centralized VANETs. Simulation results show that the proposed scheme outperforms the other two existing centralized MAC schemes. © 2011 IEEE.

关键词： Quality of service

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Fused Data Structures for Handling Multiple Faults in Distributed Systems

Fused Data Structures for Handling Multiple Faults in Distri...

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International Conference on Distributed Computing Systems

作者： Bharath Balasubramanian Vijay K. Garg Parallel and Distributed Systems Laboratory Department of Electrical and Computer Engineering University of Texas Austin USA

The paper describes a technique to correct crash faults in large data structures hosted on distributed servers, based on the concept of fused backups. The prevalent solution to this problem is replication. To correct f crash faults among n distinct data structures, replication requires nf additional replicas. If each of the primaries contains O(m) nodes of O(s) size each, this translates to O(nmsf) total backup space. Our technique uses a combination of erasure correcting codes and selective replication to correct f crash faults using just f additional backups consuming O(msf) total backup space, while incurring minimal overhead during normal operation. Since the data is maintained in the coded form, recovery is costly as compared to replication. However, in a system with infrequent faults, the savings in space outweighs the cost of recovery. We explore the theory and algorithms for these fused backups and provide a library of such backups for all the data structures in the Java 6 Collection framework. Our experimental evaluation confirms that fused backups are space-efficient as compared to replication (almost n times), while they cause very little overhead for updates. Many real world distributed systems such as Amazon's Dynamo data store use replication to achieve reliability. An alternate, fusion-based design can result in significant savings in space as well as other resources such as power.

关键词： Servers computer crashes Indexes Arrays Fault tolerance Fault tolerant systems

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Mechanical and Thermophysical Properties of Silicon Nitride Thin Films at High Temperatures Using In-Situ Mems Temperature Sensors

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MRS Online Proceedings Library 2011年第1期546卷 97-102页

作者： Patricia Nieva Haruna Tada Paul Zavracky George Adams Ioannis Miaoulis Peter Wong Microfabrication Laboratory Department of Electrical and Computer Engineering Northeastern University USA Thermal Analysis of Materials Processing Laboratory College of Engineering Tufts University USA

The optimization of microelectronic devices and Microelectromechanical Systems (MEMS) technology depends on the knowledge of the mechanical and thermophysical properties of the thin film materials used to fabricate them. The thickness, stoichiometry, structure and thermal history can affect the properties of thin films causing their mechanical and thermophysical properties to diverge from bulk values. Moreover, it is known that the mechanical and thermophysical properties of thin films vary considerably at different temperatures. Bulk properties of semiconductors have been characterized over a wide range of temperatures; however there is limited information on thin film properties of silicon-based compounds such as silicon nitride, specially at high temperatures. In our work, MEMS devices designed to record the localized maximum temperature during high temperature thermal processes, which we call Breaking T-MEMS, will be presented as a way to determine some of the mechanical properties (Young’s modulus and fracture strength) and thermophysical properties (coefficient of thermal expansion) of silicon-rich nitride thin films at high temperatures. The Breaking T-MEMS device consists of a thin film bridge suspended over a substrate. During testing, the devices are thermally loaded in tension by heating the sample. The low coefficient of thermal expansion of the film relative to that of the substrate causes the thin film bridge to break at a specific temperature. Through a combination of indirect experimental measurements, analytical expressions, numerical and statistical analysis, and if the experiments are conducted using at least two different substrates of known temperaturedependent coefficients of thermal expansion, some of the material properties of the film can be calculated from the breaking temperatures of various devices. The two candidate materials for the substrate are silicon and aluminum oxide (sapphire).

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Scheduling in wireless ad hoc networks with successive interference cancellation

Scheduling in wireless ad hoc networks with successive inter...

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IEEE Annual Joint Conference: INFOCOM, IEEE computer and Communications Societies

作者： Shaohe Lv Weihua Zhuang Xiaodong Wang Xingming Zhou National Laboratory of Parallel and Distributed Processing National University of Defense Technology Changsha Hunan China Department of Electrical and Computer Engineering University of Waterloo Waterloo ONT Canada

ISBN: (纸本)9781424499199

Successive interference cancellation (SIC) is an effective way of multipacket reception (MPR) to combat interference in wireless networks. To understand the potential MPR advantages, we study link scheduling in an ad hoc network with SIC at the physical layer. The fact that the links detected sequentially by SIC are correlated at the receiver poses key technical challenges. We characterize the link dependence and propose simultaneity graph (SG) to capture the effect of SIC. Then interference number is defined to measure the interference of a link. We show that scheduling over SG is NP-hard and the maximum interference number bounds the performance of maximal greedy schemes. An independent set based greedy scheme is explored to efficiently construct a maximal feasible schedule. Moreover, with careful selection of link ordering, we present a scheduling scheme that improves the bound. The performance is evaluated by both simulations and measurements in testbed. The throughput gain is on average 40% and up to 120% over IEEE 802.11. The complexity of SG is comparable with that of conflict graph, especially when the network size is not large.

关键词： Interference Silicon carbide Receivers Schedules Protocols Wireless networks Scheduling

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A nested superdirective generalized sidelobe canceller for speech enhancement

A nested superdirective generalized sidelobe canceller for s...

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International Conference on Information, Communications and Signal processing

作者： Parinaz Khayeri Hamid Reza Abutalebi Vahid Abootalebi Speech Processing Research Laboratory Electrical and Computer Engineering Department Yazd University Yazd Iran Electrical and Computer Engineering Department Yazd University Yazd Iran

This paper deals with the problem of microphone array speech enhancement using a hybrid Generalized Sidelobe Canceller (GSC) and Super-Directive Beamformer (SDB). While GSC is one of the most practical architectures for reducing the directional noises, SDB is a superior choice in the case of diffuse noise fields. In this research, we have combined these two structures to improve the performance of speech enhancement system in realistic noisy conditions. Furthermore, we have employed a Linear Constrained Minimum Variance (LCMV) beamformer instead of blocking matrix (in GSC) to generalize the good performance of the system for different arrival directions of desired speech. Finally, we have proposed nested sub-array implementation of the hybrid system to take advantages of the subband processing of wideband speech signal. Our experiments show the effectiveness of the proposed modifications in different input SNR values. The comparative evaluations demonstrate the superiority of the proposed system in noise reduction from speech in real-life conditions (where diffuse, incoherent, and directional noises are present, simultaneously).

关键词： Noise Microphones Arrays Speech Speech enhancement Array signal processing Vectors

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Objective Measure of Upper Extremity Motor Impairment in Parkinson's Disease with Inertial Sensors

Objective Measure of Upper Extremity Motor Impairment in Par...

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Annual International Conference of the IEEE engineering in Medicine and Biology Society

作者： Jeffrey D. Hoffman James McNames Biomedical Signal Processing Laboratory and graduate student in the Department of Electrical and Computer Engineering at Portland State University Department of Electrical and Computer Engineering at Portland State University

ISBN: (纸本)9781424441211

Functional motor impairment caused by Parkinson's disease and other movement disorders is currently measured with rating scales such as the Unified Parkinson's Disease Rating Scale (UPDRS). These are typically comprised of a series of simple tasks that are visually scored by a trained rater. We developed a method to objectively quantify three upper extremity motor tasks directly with a wearable inertial sensor. Specifically, we used triaxial gyroscopes and adaptive filters to quantify how predictable and regular the signals were. We found that simply using the normalized mean squared error (NMSE) as a test statistic permitted us to distinguish between subjects with and without Parkinson's disease who were matched for age, height, and weight. A forward linear predictor based on the Kalman filter was able to attain areas under the curve (AUC) in receiver operator characteristic (ROC) curves in the range of 0.76 to 0.83. Further studies and development are warranted. This technology has the potential to more accurately measure the motor signs of Parkinson's disease. This may reduce statistical bias and variability of rating scales, which could lead to trials with fewer subjects, less cost, and shorter duration.

关键词： Parkinson Disease inertia sensor Rating Scales Motor Disorders Statistical Biases Kalman filters Upper Extremity adaptive filters

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Universal steganalysis based on local prediction error in wavelet domain

Universal steganalysis based on local prediction error in wa...

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7th International Conference on Intelligent Information Hiding and Multimedia Signal processing, IIHMSP 2011

作者： Shojaei-Hashemi, Anahita Mehdipour-Ghazi, Mostafa Ghaemmaghami, Shahrokh Soltanian-Zadeh, Hamid School of Electrical and Computer Engineering College of Engineering University of Tehran Tehran Iran Electronics Research Institute Sharif University of Technology Tehran Iran Control and Intelligent Processing Center of Excellence School of Electrical and Computer Engineering University of Tehran Tehran Iran Image Analysis Laboratory Department of Radiology Henry Ford Health System Detroit MI United States

ISBN: (纸本)9780769545172

A passive universal image steganalysis method is proposed that is shown to be of higher detection accuracy than existing truly blind steganalysis methods including Farid's and the WAM. This is achieved by improving some weaknesses of Farid's steganalysis scheme in feature extraction, that is, instead of deriving an over-determined equation system for each sub band of the wavelet decomposition, the sub bands are divided into overlapping blocks and an over-determined equation system is constructed for each block. To guarantee the existence of finite answers, the over-determined equation systems are solved in a way different from Farid's by using Moore-Penrose pseudo-inverse concept. Further improvement to the performance is achieved by adding diagonal directions and increasing the number of moments. The comparative evaluations confirm the superiority of the proposed method over prevalent blind steganalysis schemes. © 2011 IEEE.

关键词： Wavelet decomposition

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Universal image steganalysis against spatial-domain steganography based on energy distribution of singular values

Universal image steganalysis against spatial-domain steganog...

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7th International Conference on Information Technology and Application, ICITA 2011

作者： Shojaei-Hashemi, Anahita Soltanian-Zadeh, Hamid Ghaemmagham, Shahrokh Kamarei, Mahmoud School of Electrical and Computer Engineering College of Engineering University of Tehran Tehran Iran Control and Intelligent Processing Center of Excellence School of Electrical and Computer Engineering University of Tehran Tehran Iran Image Analysis Laboratory Department of Radiology Henry Ford Health System Detroit MI United States Electronics Research Institute Sharif University of Technology Tehran Iran

ISBN: (纸本)9780980326741

A passive image steganalysis method is proposed to universally detect spatial-domain steganography schemes. It is shown to have better performance than universal steganalyzers known to be powerful in spatial domain, including the WFLogSv and the WAM methods. This level of accuracy is the result of improving the WFLogSv steganalyzer by considering a more comprehensive relationship between the singular values of each image block and the linear correlation of the rows and the columns. That is, instead of the closeness of the lower singular values to zero, the energy distribution of the singular values is investigated. An innovative measure is proposed for this investigation, which is inspired from arithmetic mean-geometric mean inequality. Experimental results confirm the supremacy of the proposed steganalysis scheme over its counterparts.

关键词： Singular value decomposition

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