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Time Synchronization for Wireless Sensor Networks Using Adaptive Linear Prediction

INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 2015年第10期11卷 1-9页

作者： Xing, Yulong Chen, Yongrui Yi, Weidong Duan, Chenghua Univ Chinese Acad Sci Beijing 100049 Peoples R China

Time synchronization is a crucial component in wireless sensor networks (WSN), especially for location-aware applications. The precision of time-based localization algorithms is closely related to the accuracy of synchronization. The estimation of synchronization errors in most of the existing time synchronization algorithms is based on some statistical distribution models. However, these models may not be able to accurately describe the synchronization errors due to the uncertainties in clock drift and message delivery delay in synchronization. Considering that the synchronization errors are highly temporally correlated (short-term correlation), in this paper, we present an adaptive linear prediction synchronization (ALPS) scheme for WSN. By applying linear prediction on synchronization errors and adaptively adjusting prediction coefficients based on the difference between the estimated values and the real values, ALPS enhances synchronization accuracy at a relatively low cost. ALPS has been implemented on the Tmote-sky platform. As experiment results demonstrate, compared with RBS and TPSN, ALPS cuts synchronization cost by almost 50% while achieving the same accuracy;compared with DMTS and PulseSync, ALPS reduces the MSE (mean square error) of synchronization errors by 41% and 24%, respectively, with the same cost.

关键词： WIRELESS sensor networks WIRELESS localization SYNCHRONIZATION computer algorithms ADAPTIVE control systems PREDICTION models ESTIMATION theory

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Lowering the Technical Threshold for Organizers to Create and Deliver Mobile Crowd Sensing Applications

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INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 2015年第11期11卷 1-15页

作者： Wang, Jiangtao Wang, Yasha He, Yuanduo Minist Educ Key Lab High Confidence Software Technol Beijing 100871 Peoples R China Peking Univ Sch Elect Engn & Comp Sci Beijing 100871 Peoples R China Peking Univ Natl Engn Res Ctr Software Engn Beijing 100871 Peoples R China

In order to lower the technical threshold for creating and delivering Mobile Crowd Sensing Applications (MCSAs), several frameworks or toolkits have been developed, but they either fail to provide general support or still require relatively professional software development skills. Besides, the application delivery to the participants is not precise enough, because they only consider the constraints predefined by the organizers without taking the participant-side factors into account. In this paper, we propose a prototype toolkit for the organizers without software development skills to build MCSA in a rather quick and simple way. First, in terms of the application creation, it enables organizers to build MCSA by just doing some simple settings, which totally eliminates the requirement of programming skills. Second, in terms of the application delivery, it selects participants who are more likely to accept the created applications by mining their participation history. Finally, we demonstrate the expressiveness and usability for the application creation and evaluate the effectiveness of the willingness-based participant selection algorithm for the application delivery.

关键词： MOBILE computing computer software development PROTOTYPES computer algorithms DATA mining

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Adaptive quantum computation in changing environments using projective simulation

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SCIENTIFIC REPORTS 2015年第1期5卷 12874-12874页

作者： Tiersch, M. Ganahl, E. J. Briegel, H. J. Univ Innsbruck Inst Theoret Phys A-6020 Innsbruck Austria Austrian Acad Sci Inst Quantum Opt & Quantum Informat A-6020 Innsbruck Austria

Quantum information processing devices need to be robust and stable against external noise and internal imperfections to ensure correct operation. In a setting of measurement-based quantum computation, we explore how an intelligent agent endowed with a projective simulator can act as controller to adapt measurement directions to an external stray field of unknown magnitude in a fixed direction. We assess the agent's learning behavior in static and time-varying fields and explore composition strategies in the projective simulator to improve the agent's performance. We demonstrate the applicability by correcting for stray fields in a measurement-based algorithm for Grover's search. Thereby, we lay out a path for adaptive controllers based on intelligent agents for quantum information tasks.

关键词： QUANTUM computing computer simulation INFORMATION storage & retrieval systems INTELLIGENT agents (computer software) computer algorithms

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Stop Apologizing for Your Samples, Start Embracing Them

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INDUSTRIAL AND ORGANIZATIONAL PSYCHOLOGY-PERSPECTIVES ON SCIENCE AND PRACTICE 2015年第2期8卷 228-U134页

作者： Zhu, Xiaoyuan (Susan) Barnes-Farrell, Janet L. Dalal, Dev K. Univ Connecticut Dept Psychol Storrs CT 06269 USA

Landers and Behrend (2015) call for editors and reviewers to resist using heuristics when evaluating samples in research as well as for researchers to cautiously consider choosing the samples appropriate for their research questions. Whereas we fully agree with the former conclusion, we believe the latter can be extended even further to encourage researchers to embrace the strengths of their samples for understanding their research rather than simply defending their samples. We believe that samples are not inherently better or worse but rather better suited for different research objectives. In this commentary, we identify three continua on which research goals can differ to demonstrate that all samples can inform science. Depending on the position of one's research on these continua, different samples exhibit different strengths; the continua described below can be used to anchor one's sample to demonstrate how it can benefit, rather than limit, research conclusions. As discussed in the focal article, researchers will often apologize for their convenience samples as one of a litany of limitations; we hope that researchers will move sampling issues out of the limitations section and into the main discussion.

关键词： SAMPLING (Process) SAMPLING (Statistics) HEURISTIC algorithms computer algorithms HEURISTIC programming

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Improvement of High-Power Three-Level Explosion-Proof Inverters Using Soft Switching Control Based on Optimized Power-Loss Algorithm

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JOURNAL OF ELECTRICAL AND computer ENGINEERING 2015年第1期2015卷 1-14页

作者： Xu, Shi-Zhou He, Feng-You China Univ Min & Technol Dept Informat & Elect Engn 1 Daxue Rd Xuzhou 221116 Jiangsu Peoples R China

The high-power three-level explosion-proof inverters demand high thermal stability of power devices, and a set of theories and methods is needed to achieve an accurate power-loss calculation of power devices, to establish heat dissipationmodel, and ultimately to reduce the power loss to improve thermal stability of system. In this paper, the principle of neutral point clamped three-level (NPC3L) inverter is elaborated firstly, and a fourth-order RC equivalent circuit of IGBT is derived, on which basis the power-loss model of IGBT and the optimized maternal power-loss thermal model, using an optimized power-loss algorithm, are established. Secondly, in accordance with the optimized maternal power-loss thermal model, the generic formulas of power-loss calculation are deduced to calculate the power-loss modification values of NPC3L and soft switching three-level (S3L) inverters, which will be the thermal sources during thermal analysis for maternal power-loss thermal models. Finally, the experiment conducted on the 2.1MWexperimental platform shows that S3L inverter has the same excellent output characteristics with NPC3L inverter, reduces the power loss significantly by 213W in each half-bridge, and decreases the temperature by 10 degrees C, coinciding with the theoretical calculation, which verifies the accuracy of optimized power-loss algorithm and the effectiveness of the improvement.

关键词： ELECTRIC inverters SWITCHING circuits THERMAL stability computer algorithms ELECTRIC loss in electric power systems ENERGY dissipation MATHEMATICAL optimization

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Efficient Cross-Layer Optimization Algorithm for Data Transmission in Wireless Sensor Networks

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JOURNAL OF ELECTRICAL AND computer ENGINEERING 2015年第1期2015卷 1-6页

作者： Li, Chengtie Wang, Jinkuan Li, Mingwei Northeastern Univ Sch Informat Sci & Engn Shenyang 110819 Liaoning Peoples R China

In this paper, we address the problems of joint design for channel selection, medium access control (MAC), signal input control, and power control with cooperative communication, which can achieve tradeoff between optimal signal control and power control in wireless sensor networks (WSNs). The problems are solved in two steps. Firstly, congestion control and link allocation are separately provided at transport layer and network layer, by supply and demand based on compressed sensing (CS). Secondly, we propose the cross-layer scheme to minimize the power cost of the whole network by a linear optimization problem. Channel selection and power control scheme, using the minimum power cost, are presented at MAC layer and physical layer, respectively. These functions interact through and are regulated by congestion rate so as to achieve a global optimality. Simulation results demonstrate the validity and high performance of the proposed algorithm.

关键词： WIRELESS sensor networks CROSS-layer designs (Telecommunications) DATA transmission systems computer algorithms COMPRESSED sensing (Signal processing)

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Obstacle Avoidance Algorithm for 7-DOF Redundant Anthropomorphic Arm

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JOURNAL OF CONTROL SCIENCE AND ENGINEERING 2015年第1-28期2015卷 540259-540259页

作者： Shen, Haoyu Wu, Hongtao Chen, Bai Jiang, Yanjie Yan, Cheng Nanjing Univ Aeronaut & Astronaut Coll Mech & Elect Engn Nanjing 210016 Jiangsu Peoples R China

To deal with the problem of obstacle avoidance for redundant robots, an obstacle avoidance algorithm based on the internal motion of the 7-DOF redundant anthropomorphic armis presented. The motion of that critical points move away from the closest points on the obstacles is defined as obstacle avoiding motion. Two transitioning variables were used to make a smooth, continuous transition between the primary and the secondary tasks. Using this approach, the robot can get the target configuration while avoiding the obstacles. Finally, the validity of the obstacle avoidance algorithm based on transitioning between tasks is manifested by simulation. The results show that, for the obstacle avoiding problem, the redundant robot not only can realize the obstacle avoidance, but also prevents the conflict between tasks by the proposed approach.

关键词： ROBOTS -- Control systems ARTIFICIAL intelligence ROBOT motion computer simulation computer algorithms

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Robust and highly performant ring detection algorithm for 3d particle tracking using 2d microscope imaging

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SCIENTIFIC REPORTS 2015年第1期5卷 13584-13584页

作者： Afik, Eldad Weizmann Inst Sci Dept Phys Complex Syst IL-76100 Rehovot Israel

Three-dimensional particle tracking is an essential tool in studying dynamics under the microscope, namely, fluid dynamics in microfluidic devices, bacteria taxis, cellular trafficking. The 3d position can be determined using 2d imaging alone by measuring the diffraction rings generated by an out-of- focus fluorescent particle, imaged on a single camera. Here I present a ring detection algorithm exhibiting a high detection rate, which is robust to the challenges arising from ring occlusion, inclusions and overlaps, and allows resolving particles even when near to each other. It is capable of real time analysis thanks to its high performance and low memory footprint. The proposed algorithm, an offspring of the circle Hough transform, addresses the need to efficiently trace the trajectories of many particles concurrently, when their number in not necessarily fixed, by solving a classification problem, and overcomes the challenges of finding local maxima in the complex parameter space which results from ring clusters and noise. Several algorithmic concepts introduced here can be advantageous in other cases, particularly when dealing with noisy and sparse data. The implementation is based on open-source and cross-platform software packages only, making it easy to distribute and modify. It is implemented in a microfluidic experiment allowing real-time multi-particle tracking at 70 Hz, achieving a detection rate which exceeds 94% and only 1% false-detection.

关键词： PARTICLE tracking velocimetry DIFFRACTION patterns HOUGH transforms computer algorithms computer software development

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A Real-Time Video Watermarking Algorithm for Authentication of Small-Business Wireless Surveillance Networks

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INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 2015年第9期11卷 1-11页

作者： Liu, Shaohui Chen, Daniel Bo-Wei Gong, Long Ji, Wen Seo, Sanghyun Harbin Inst Technol Sch Comp Sci & Technol Harbin 150001 Peoples R China Natl Cheng Kung Univ Dept Elect Engn Tainan 70101 Taiwan Chinese Acad Sci Inst Comp Technol Beijing 100190 Peoples R China Elect & Telecommun Res Inst Daejeon 305700 South Korea

In some business applications, all kinds of cameras sensors are employed in a distributed way to capture videos for different tasks such as surveillance. Once some illegal actions happen, then somebody or some organization wants to forge or replace some surveillance video clips to destroy evidences or obtain illegal profits. How to authenticate the genuineness and integrity of the source video or trace the source of a video information leak becomes a growing requirement in these small businesses. Fortunately, video watermark just provides an effective technology to resolve this issue. This paper proposes a real-time video watermarking scheme for MPEG, where firstly exploits fast scenes segmentation to original video sequence and adaptively selects appropriate scenes to be embedded. Furthermore, visual model is utilized to modulate watermark strength. Watermarks are embedded by adjusting the number of bit1 in the bitstreams through changing level of run-level pairs. Experiment results show little loss of video quality and also exhibit excellent robustness against many attacks. As watermark is directly detected in bitstreams domain, real-time detection becomes a reality. In addition, the embedding strategy guarantees that the bit rate is not increased and the experiments also validate it.

关键词： REAL-time computing VIDEO watermarking computer algorithms computerS -- Access control SMALL business WIRELESS sensor networks

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Selectively-informed particle swarm optimization

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SCIENTIFIC REPORTS 2015年第1期5卷 9295-9295页

作者： Gao, Yang Du, Wenbo Yan, Gang Beihang Univ Sch Elect & Informat Engn Beijing 100191 Peoples R China Northeastern Univ Ctr Complex Network Res Boston MA 02115 USA Northeastern Univ Dept Phys Boston MA 02115 USA

Particle swarm optimization (PSO) is a nature-inspired algorithm that has shown outstanding performance in solving many realistic problems. In the original PSO and most of its variants all particles are treated equally, overlooking the impact of structural heterogeneity on individual behavior. Here we employ complex networks to represent the population structure of swarms and propose a selectively-informed PSO (SIPSO), in which the particles choose different learning strategies based on their connections: a densely-connected hub particle gets full information from all of its neighbors while a non-hub particle with few connections can only follow a single yet best-performed neighbor. Extensive numerical experiments on widely-used benchmark functions show that our SIPSO algorithm remarkably outperforms the PSO and its existing variants in success rate, solution quality, and convergence speed. We also explore the evolution process from a microscopic point of view, leading to the discovery of different roles that the particles play in optimization. The hub particles guide the optimization process towards correct directions while the non-hub particles maintain the necessary population diversity, resulting in the optimum overall performance of SIPSO. These findings deepen our understanding of swarm intelligence and may shed light on the underlying mechanism of information exchange in natural swarm and flocking behaviors.

关键词： PARTICLE swarm optimization computer algorithms MATHEMATICAL optimization GENETIC algorithms COMBINATORIAL optimization

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