898 research outputs found

    Detection of False Data Injection Attacks in Smart Grid under Colored Gaussian Noise

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    In this paper, we consider the problems of state estimation and false data injection detection in smart grid when the measurements are corrupted by colored Gaussian noise. By modeling the noise with the autoregressive process, we estimate the state of the power transmission networks and develop a generalized likelihood ratio test (GLRT) detector for the detection of false data injection attacks. We show that the conventional approach with the assumption of Gaussian noise is a special case of the proposed method, and thus the new approach has more applicability. {The proposed detector is also tested on an independent component analysis (ICA) based unobservable false data attack scheme that utilizes similar assumptions of sample observation.} We evaluate the performance of the proposed state estimator and attack detector on the IEEE 30-bus power system with comparison to conventional Gaussian noise based detector. The superior performance of {both observable and unobservable false data attacks} demonstrates the effectiveness of the proposed approach and indicates a wide application on the power signal processing.Comment: 8 pages, 4 figures in IEEE Conference on Communications and Network Security (CNS) 201

    Direct Aerobic Carbonylation of C(sp2)-H and C(sp3)-H Bonds through Ni/Cu Synergistic Catalysis with DMF as the CO Source

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    The direct carbonylation of aromatic sp2 and unactivated sp3 C–H bonds of amides was achieved via nickel/copper catalysis under atmospheric O2 with the assistance of a bidentate directing group. The sp2 C–H functionalization showed high regioselectivity and good functional group compatibility. The sp3 C–H functionalization showed high site-selectivity by favoring the C–H bonds of α-methyl groups over those of the α-methylene, β- or γ-methyl groups. Moreover, this reaction showed a predominant preference for functionalizing the α-methyl over α-phenyl group. Mechanistic studies revealed that nickel/copper synergistic catalysis is involved in this process

    Electrocardiogram Baseline Wander Suppression Based on the Combination of Morphological and Wavelet Transformation Based Filtering

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    One of the major noise components in electrocardiogram (ECG) is the baseline wander (BW). Effective methods for suppressing BW include the wavelet-based (WT) and the mathematical morphological filtering-based (MMF)algorithms. However, the T waveform distortions introduced by the WTand the rectangular/trapezoidal distortions introduced by MMF degrade the quality of the output signal. Hence, in this study, we introduce a method by combining the MMF and WTto overcome the shortcomings of both existing methods. To demonstrate the effectiveness of the proposed method, artificial ECG signals containing a clinicalBW are used for numerical simulation, and we also create a realistic model of baseline wander to compare the proposed method with other state-of-the-art methods commonly used in the literature. /e results show that the BW suppression effect of the proposed method is better than that of the others. Also, the new method is capable of preserving the outline of the BW and avoiding waveform distortions caused by the morphology filter, thereby obtaining an enhanced quality of ECG

    Development of a Wearable-Sensor-Based Fall Detection System

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    Fall detection is a major challenge in the public healthcare domain, especially for the elderly as the decline of their physical fitness, and timely and reliable surveillance is necessary to mitigate the negative effects of falls. This paper develops a novel fall detection system based on a wearable device. The system monitors the movements of human body, recognizes a fall from normal daily activities by an effective quaternion algorithm, and automatically sends request for help to the caregivers with the patient’s location

    Boundedness of Parametrized Littlewood-Paley Operators with Nondoubling Measures

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    Let μ be a nonnegative Radon measure on â„Âd which only satisfies the following growth condition that there exists a positive constant C such that μ(B(x,r))≤Crn for all x∈â„Âd, r>0 and some fixed n∈(0,d]. In this paper, the authors prove that for suitable indexes àand λ, the parametrized gλ∗ function ℳλ∗,àis bounded on Lp(μ) for p∈[2,∞) with the assumption that the kernel of the operator ℳλ∗,àsatisfies some Hörmander-type condition, and is bounded from L1(μ) into weak L1(μ) with the assumption that the kernel satisfies certain slightly stronger Hörmander-type condition. As a corollary, ℳλ∗,àwith the kernel satisfying the above stronger Hörmander-type condition is bounded on Lp(μ) for p∈(1,2). Moreover, the authors prove that for suitable indexes àand λ,ℳλ∗,àis bounded from L∞(μ) into RBLO(μ) (the space of regular bounded lower oscillation functions) if the kernel satisfies the Hörmander-type condition, and from the Hardy space H1(μ) into L1(μ) if the kernel satisfies the above stronger Hörmander-type condition. The corresponding properties for the parametrized area integral ℳSàare also established in this paper

    On the Study of Global Solutions for a Nonlinear Equation

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    The well-posedness of global strong solutions for a nonlinear partial differential equation including the Novikov equation is established provided that its initial value V 0 ( ) satisfies a sign condition and V 0 ( ) ∈ ( ) with > 3/2. If the initial value V 0 ( ) ∈ ( ) (1 ≤ ≤ 3/2) and the mean function of (1 − 2 )V 0 ( ) satisfies the sign condition, it is proved that there exists at least one global weak solution to the equation in the space V( , ) ∈ 2 ([0, +∞), ( )) in the sense of distribution and V ∈ ∞ ([0, +∞) × )

    The Local Stability of Solutions for a Nonlinear Equation

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    The approach of Kruzkov’s device of doubling the variables is applied to establish the local stability of strong solutions for a nonlinear partial differential equation in the space L1(R) by assuming that the initial value only lies in the space L1(R)∩L∞(R)
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