5,544 research outputs found

    A Review of Fault Diagnosing Methods in Power Transmission Systems

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    Transient stability is important in power systems. Disturbances like faults need to be segregated to restore transient stability. A comprehensive review of fault diagnosing methods in the power transmission system is presented in this paper. Typically, voltage and current samples are deployed for analysis. Three tasks/topics; fault detection, classification, and location are presented separately to convey a more logical and comprehensive understanding of the concepts. Feature extractions, transformations with dimensionality reduction methods are discussed. Fault classification and location techniques largely use artificial intelligence (AI) and signal processing methods. After the discussion of overall methods and concepts, advancements and future aspects are discussed. Generalized strengths and weaknesses of different AI and machine learning-based algorithms are assessed. A comparison of different fault detection, classification, and location methods is also presented considering features, inputs, complexity, system used and results. This paper may serve as a guideline for the researchers to understand different methods and techniques in this field

    A survey of localization in wireless sensor network

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    Localization is one of the key techniques in wireless sensor network. The location estimation methods can be classified into target/source localization and node self-localization. In target localization, we mainly introduce the energy-based method. Then we investigate the node self-localization methods. Since the widespread adoption of the wireless sensor network, the localization methods are different in various applications. And there are several challenges in some special scenarios. In this paper, we present a comprehensive survey of these challenges: localization in non-line-of-sight, node selection criteria for localization in energy-constrained network, scheduling the sensor node to optimize the tradeoff between localization performance and energy consumption, cooperative node localization, and localization algorithm in heterogeneous network. Finally, we introduce the evaluation criteria for localization in wireless sensor network

    A HOLISTIC APPROACH FOR SECURITY REQUIREMENT SPECIFICATION FOR LOW-COST, DISTRIBUTED UBIQUITOUS SYSTEMS

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    The class of low-cost, distributed ubiquitous systems represents a computing mode where a system has small, inexpensive networked processing devices, distributed at all scales throughout business activities and everyday life. The unique features of such a class of ubiquitous systems make the security analysis different from that for the centralized computing paradigms. This paper presents a holistic approach for security requirement analysis for low cost, distributed ubiquitous systems. Rigorous security analysis needs both quantitative and qualitative approaches to produce the holistic view and the robust data regarding the security features that a system must have in order to meet users’ security expectations. Our framework can assist system administrators to specify key security properties for a low-cost, distributed ubiquitous system and to define the specific security requirements for such a system. We applied Bayesian network and stochastic process algebra to incorporate probabilistic analysis to the framework

    Combination of Evidence in Dempster-Shafer Theory

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