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Distributed Hybrid Localization Using RSS Threshold Based Connectivity Information and Iterative Location Update

INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 2015年第2期11卷 11-11页

作者： Maung, Nyein Aye Maung Kawai, Makoto Ritsumeikan Univ Grad Sch Informat Sci & Engn Kusatsu 5258577 Japan

Resource constraints of wireless ad hoc and sensor networks prohibit high accuracy range-based localization schemes which require specialized hardware for ranging. On the other hand, cost-effective range-free schemes offer lower accuracy and grant their applicability only to large-scale networks. This paper proposes an efficient distributed hybrid solution which integrates received signal strength (RSS) based ranging and connectivity-based range-free approaches to improve the localization accuracy without any extra ranging hardware and to be adaptable to any network size. First, it configures the connectivity information using available RSS measurements and a predefined RSS threshold. Optimal RSS threshold value that minimizes the error for a particular network to be localized is derived as a function of the total number of nodes and the network size. And then, localization accuracy is further improved by introducing the use of regulated hop-count values. Finally, locations of the nodes are iteratively updated using both connectivity information and RSS-based distance information between the nodes to get more precise localization accuracy. Effectiveness of the proposed scheme is evaluated with both experiments and simulations, and results show that the proposed scheme achieves significant performance improvement over existing schemes.

关键词： thresholding algorithms ITERATIVE methods (Mathematics) DISTRIBUTED sensors SIGNAL processing AD hoc networks (Computer networks) SENSOR networks

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A new approach for thresholding spectral change detection using multispectral and hyperspectral image data, a case study over Sokolov, Czech republic

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INTERNATIONAL JOURNAL OF REMOTE SENSING 2014年第4期35卷 1563-1584页

作者： Adar, Simon Shkolnisky, Yoel Ben Dor, Eyal Tel Aviv Univ Porter Sch Environm Studies IL-69978 Tel Aviv Israel Tel Aviv Univ Dept Appl Math IL-69978 Tel Aviv Israel Tel Aviv Univ Dept Geog IL-39040 Tel Aviv Israel

Change detection and multitemporal analyses aim to detect changes occurring over a specific geographical area using two or more images acquired at two or more different times. In this article, we present a new thresholding approach for unsupervised change detection. This approach focuses on determining the threshold that discriminates between change and no-change pixels. The differences between pixels in the two images are associated with real changes or noise. We propose a thresholding scheme that separates the threshold into two parts: (1) a spectral domain threshold that accounts for errors related to sensor stability, atmospheric conditions, and data-processing variations, and (2) a spatial domain threshold associated with georectification errors. We demonstrate our method using both multispectral Landsat images and airborne imaging spectroscopy HyMap images. The results show that the spectral domain threshold gives high detection capabilities with moderate false-alarm rate. Adding the spatial domain threshold to the spectral domain threshold reduces the false-alarm rates while maintaining good detection capabilities. View full text

关键词： thresholding algorithms HYPERSPECTRAL imaging systems GEOGRAPHICAL location codes PIXELS

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Complex signal analysis for wind turbine planetary gearbox fault diagnosis via iterative atomic decomposition thresholding

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JOURNAL OF SOUND AND VIBRATION 2014年第20期333卷 5196-5211页

作者： Feng, Zhipeng Liang, Ming Univ Sci & Technol Beijing Sch Mech Engn Beijing 100083 Peoples R China Univ Ottawa Dept Mech Engn Ottawa ON K1N 6N5 Canada

The vibration signals from complex structures such as wind turbine (WT) planetary gearboxes are intricate. Reliable analysis of such signals is the key to success in fault detection and diagnosis for complex structures. The recently proposed iterative atomic decomposition thresholding (IADT) method has shown to be effective in extracting true constituent components of complicated signals and in suppressing background noise interferences. In this study, such properties of the IADT are exploited to analyze and extract the target signal components from complex signals with a focus on WT planetary gearboxes under constant running conditions. Fault diagnosis for WT planetary gearboxes has been a very important yet challenging issue due to their harsh working conditions and complex structures. Planetary gearbox fault diagnosis relies on detecting the presence of gear characteristic frequencies or monitoring their magnitude changes. However, a planetary gearbox vibration signal is a mixture of multiple complex components due to the unique structure, complex kinetics and background noise. As such, the IADT is applied to enhance the gear characteristic frequencies of interest, and thereby diagnose gear faults. Considering the spectral properties of planetary gearbox vibration signals, we propose to use Fourier dictionary in the IADT so as to match the harmonic waves in frequency domain and pinpoint the gear fault characteristic frequency. To reduce computing time and better target at more relevant signal components, we also suggest a criterion to estimate the number of sparse components to be used by the IADT. The performance of the proposed approach in planetary gearbox fault diagnosis has been evaluated through analyzing the numerically simulated, lab experimental and on-site collected signals. The results show that both localized and distributed gear faults, both the sun and planet gear faults, can be diagnosed successfully. (C) 2014 Elsevier Ltd. All rights reserved.

关键词： SIGNAL processing WIND turbines DECOMPOSITION (Mathematics) ITERATIVE methods (Mathematics) thresholding algorithms GEARBOXES (Machinery)

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An Improved Quantum-Inspired Genetic Algorithm for Image Multilevel thresholding Segmentation

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-12页

作者： Zhang, Jian Li, Huanzhou Tang, Zhangguo Lu, Qiuping Zheng, Xiuqing Zhou, Jiliu Sichuan Normal Univ Sch Phys & Elect Engn Chengdu 610066 Peoples R China Sichuan Normal Univ Coll Comp Sci Chengdu 610066 Peoples R China Sichuan Univ Coll Comp Sci Chengdu 610065 Peoples R China

A multilevel thresholding algorithm for histogram-based image segmentation is presented in this paper. The proposed algorithm introduces an adaptive adjustment strategy of the rotation angle and a cooperative learning strategy into quantum genetic algorithm ( called IQGA). An adaptive adjustment strategy of the quantum rotation which is introduced in this study helps improving the convergence speed, search ability, and stability. Cooperative learning enhances the search ability in the high-dimensional solution space by splitting a high-dimensional vector into several one-dimensional vectors. The experimental results demonstrate good performance of the IQGA in solving multilevel thresholding segmentation problem by compared with QGA, GA and PSO.

关键词： QUANTUM theory GENETIC algorithms IMAGE retrieval thresholding algorithms SEGMENTATION (Image processing)

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Visualizing gauge unification with high-scale thresholds

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Physical Review D 2015年第7期91卷 075016-075016页

作者： Sebastian A. R. Ellis James D. Wells Department of Physics Michigan Center for Theoretical Physics (MCTP) University of Michigan Ann Arbor Michigan 48109 USA

Tests of gauge coupling unification require knowledge of thresholds between the weak scale and the high scale of unification. If these scales are far separated, as is the case in most unification scenarios considered in the literature, the task can be factorized into IR and UV analyses. We advocate “Δλ plots” as an efficient IR analysis projected to the high scale. The data from these plots gives an immediate qualitative guide to the size of threshold corrections needed at the high scale (e.g., the indices of high-scale representations) and provides precise quantitative data needed to test the viability of hypothesized high-scale unification theories. Such an approach shows more clearly the reasonable prospects of nonsupersymmetric grand unification in large rank groups, and also shows the low summed values of high-scale threshold corrections required for supersymmetric unification. The latter may imply tuned cancellations of high-scale thresholds in theories based on weak-scale supersymmetry. For that reason we view nonsupersymmetric unification to be just as viable as supersymmetric unification when confining ourselves only to the question of reasonable high-scale threshold corrections needed for exact unification. We illustrate these features for a nonsupersymmetric SO(10) grand unified theory and a supersymmetric SU(5) theory.

关键词： GAUGE field theory thresholding algorithms INFRARED technology ULTRAVIOLET radiation SUPERSYMMETRY (Physics)

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Quantum secret sharing via local operations and classical communication

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SCIENTIFIC REPORTS 2015年第1期5卷 16967-16967页

作者： Yang, Ying-Hui Gao, Fei Wu, Xia Qin, Su-Juan Zuo, Hui-Juan Wen, Qiao-Yan Beijing Univ Posts & Telecommun State Key Lab Networking & Switching Technol Beijing 100876 Peoples R China Henan Polytech Univ Sch Math & Informat Sci Jiaozuo 454000 Peoples R China Hebei Normal Univ Math & Informat Sci Coll Shijiazhuang 050024 Peoples R China

We investigate the distinguishability of orthogonal multipartite entangled states in d-qudit system by restricted local operations and classical communication. According to these properties, we propose a standard (2, n)-threshold quantum secret sharing scheme (called LOCC-QSS scheme), which solves the open question in [Rahaman et al., Phys. Rev. A, 91, 022330 (2015)]. On the other hand, we find that all the existing (k, n)-threshold LOCC-QSS schemes are imperfect (or "ramp"), i. e., unauthorized groups can obtain some information about the shared secret. Furthermore, we present a (3, 4)-threshold LOCC-QSS scheme which is close to perfect.

关键词： QUANTUM cryptography QUANTUM communication CONFIDENTIAL communications INFORMATION sharing thresholding algorithms

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A Comparative Study of Improved Artificial Bee Colony algorithms Applied to Multilevel Image thresholding

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MATHEMATICAL PROBLEMS IN ENGINEERING 2013年第1期2013卷 1-17页

作者： Charansiriphaisan, Kanjana Chiewchanwattana, Sirapat Sunat, Khamron Khon Kaen Univ Fac Sci Dept Comp Sci Khon Kaen 40002 Thailand

Multilevel thresholding is a highly useful tool for the application of image segmentation. Otsu's method, a common exhaustive search for finding optimal thresholds, involves a high computational cost. There has been a lot of recent research into various metaheuristic searches in the area of optimization research. This paper analyses and discusses using a family of artificial bee colony algorithms, namely, the standard ABC, ABC/best/1, ABC/best/2, IABC/best/1, IABC/rand/1, and CABC, and some particle swarm optimization-based algorithms for searching multilevel thresholding. The strategy for an onlooker bee to select an employee bee was modified to serve our purposes. The metric measures, which are used to compare the algorithms, are the maximum number of function calls, successful rate, and successful performance. The ranking was performed by Friedman ranks. The experimental results showed that IABC/best/1 outperformed the other techniques when all of them were applied to multilevel image thresholding. Furthermore, the experiments confirmed that IABC/best/1 is a simple, general, and high performance algorithm.

关键词： BEES algorithm SEGMENTATION (Image processing) thresholding algorithms MATHEMATICAL optimization PARTICLE swarm optimization METAHEURISTIC algorithms

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Dual-Beam Histotripsy: A Low-Frequency Pump Enabling a High-Frequency Probe for Precise Lesion Formation

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IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL 2014年第2期61卷 325-340页

作者： Lin, Kuang-Wei Duryea, Alexander P. Kim, Yohan Hall, Timothy L. Xu, Zhen Cain, Charles A. Univ Michigan Dept Biomed Engn Ann Arbor MI 48109 USA

Histotripsy produces tissue fractionation through dense energetic bubble clouds generated by short, high-pressure, ultrasound pulses. When using pulses shorter than 2 cycles, the generation of these energetic bubble clouds only depends on where the peak negative pressure (P-) exceeds the intrinsic threshold of the medium (26 to 30 MPa in soft tissue with high water content). This paper investigates a strategic method for precise lesion generation in which a low-frequency pump pulse is applied to enable a sub-threshold high-frequency probe pulse to exceed the intrinsic threshold. This pump-probe method of controlling a supra-threshold volume can be called dual-beam histotripsy. A 20-element dual-frequency (500-kHz and 3-MHz elements confocally aligned) array transducer was used to generate dual-beam histotripsy pulses in red blood cell phantoms and porcine hepatic tissue specimens. The results showed that when subintrinsic-threshold pump (500-kHz) and probe (3-MHz) pulses were applied together, dense bubble clouds (and resulting lesions) were only generated when their peak negative pressures combined constructively to exceed the intrinsic threshold. The smallest reproducible lesion varied with the relative amplitude between the pump and probe pulses, and, with a higher proportion of the probe pulse, smaller lesions could be generated. When the propagation direction of the probe pulse relative to the pump pulse was altered, the shape of the produced lesion changed based on the region that exceeded intrinsic threshold. Because the low-frequency pump pulse is more immune to attenuation and aberrations, and the high-frequency probe pulse can provide precision in lesion formation, this dual-beam histotripsy approach would be very useful in situations in which precise lesion formation is required through a highly attenuative and aberrative medium, such as transcranial therapy. This is particularly true if a small low-attenuation acoustic window is available for the high-fr

关键词： TISSUES -- Wounds & injuries BUBBLE dynamics ULTRASONICS ELECTRONIC pulse techniques thresholding algorithms THEORY of wave motion PRESSURE

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Mixed Higher Order Variational Model for Image Recovery

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MATHEMATICAL PROBLEMS IN ENGINEERING 2014年第1期2014卷 1-15页

作者： Liu, Pengfei Xiao, Liang Xiu, Liancun Nanjing Univ Sci & Technol Sch Comp Sci & Engn Nanjing 210094 Jiangsu Peoples R China Nanjing Ctr China Geol Survey Nanjing 210016 Jiangsu Peoples R China

A novel mixed higher order regularizer involving the first and second degree image derivatives is proposed in this paper. Using spectral decomposition, we reformulate the new regularizer as a weighted L-1-L-2 mixed norm of image derivatives. Due to the equivalent formulation of the proposed regularizer, an efficient fast projected gradient algorithm combined with monotone fast iterative shrinkage thresholding, called, FPG-MFISTA, is designed to solve the resulting variational image recovery problems under majorization-minimization framework. Finally, we demonstrate the effectiveness of the proposed regularization scheme by the experimental comparisons with total variation (TV) scheme, nonlocal TV scheme, and current second degree methods. Specifically, the proposed approach achieves better results than related state-of-the-art methods in terms of peak signal to ratio (PSNR) and restoration quality.

关键词： IMAGE reconstruction DERIVATIVES (Mathematics) IMAGE quality analysis SIGNAL-to-noise ratio REGULARIZATION (Mathematics) thresholding algorithms

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Otsu Based Optimal Multilevel Image thresholding Using Firefly Algorithm

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MODELLING AND SIMULATION IN ENGINEERING 2014年第1期2014卷 1-17页

作者： Raja, N. Sri Madhava Rajinikanth, V. Latha, K. St Josephs Coll Engn Dept Elect & Instrumentat Engn Chennai 600119 Tamil Nadu India Anna Univ Dept Instrumentat Engn Chennai 600044 Tamil Nadu India

Histogram based multilevel thresholding approach is proposed using Brownian distribution (BD) guided firefly algorithm (FA). A bounded search technique is also presented to improve the optimization accuracy with lesser search iterations. Otsu's between-class variance function is maximized to obtain optimal threshold level for gray scale images. The performances of the proposed algorithm are demonstrated by considering twelve benchmark images and are compared with the existing FA algorithms such as Levy flight (LF) guided FA and random operator guided FA. The performance assessment comparison between the proposed and existing firefly algorithms is carried using prevailing parameters such as objective function, standard deviation, peak-to-signal ratio (PSNR), structural similarity (SSIM) index, and search time of CPU. The results show that BD guided FA provides better objective function, PSNR, and SSIM, whereas LF based FA provides faster convergence with relatively lower CPU time.

关键词： SIGNAL processing thresholding algorithms MULTILEVEL models (Statistics) IMAGE processing BROWNIAN motion ITERATIVE methods (Mathematics)

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