There are two main classes of decision fusion methods, namely hard decision fusion (HD) and soft decision fusion (SD), in which the number of bits transmitted by each local sensor to the fusion centre (FC) is always s...
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There are two main classes of decision fusion methods, namely hard decision fusion (HD) and soft decision fusion (SD), in which the number of bits transmitted by each local sensor to the fusion centre (FC) is always same, namely one bit in HD and n (n >= 2) bits in SD. However, considering that there is always a limit of bandwidth in a distributed detection system, the number of bits sent by each local sensor to the FC does not need to be the same and should be allocated reasonably and suitably. Therefore, this study proposes an optimal bit allocation scheme based on the memetic algorithm, in which the number of bits transmitted by each local sensor could be different. This scheme aims to maximise the detection probability under the limit of bandwidth for a detectionsystem with imperfect channels. The overall detection probability objective function about the number of allocated bits is derived. To optimise this objective function, an improved memetic algorithm with two local adjustment strategies, namely non-elite learning local adjustment optimisation strategy and elite greedy local adjustment optimisation strategy, is proposed to allocate the optimal number of bits. Simulation results show the efficiency and effectiveness of the proposed scheme.
The optimization of a distributed detection system with two consulting sensors is considered. The communication between the two sensors is based on a nonrandom decisions exchange scheme. Contrary to the existing consu...
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The optimization of a distributed detection system with two consulting sensors is considered. The communication between the two sensors is based on a nonrandom decisions exchange scheme. Contrary to the existing consulting schemes, in which no quality information is exchanged except a request consultation signal, we propose scheme in which additional information, such as the degree of confidence associated with the decisions, is allowed to communicate between the sensors. Direct optimization method based on search algorithm to optimize the performance of the system is used. The results obtained show the superiority of the proposed scheme over the one that does not allow information exchange. (C) 2019 Elsevier GmbH. All rights reserved.
The design of distributed detection system implements network structure in detectionsystem, enhances the link between the bottom model and the upper management. Because of network delay existing in the distributed sy...
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In the distributed detection system with multiple sensors, there are two ways for local sensors to deliver their local decisions to the fusion center (FC): a one-bit hard decision and a multiple-bit soft decision. Com...
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In the distributed detection system with multiple sensors, there are two ways for local sensors to deliver their local decisions to the fusion center (FC): a one-bit hard decision and a multiple-bit soft decision. Compared with the soft decision, the hard decision has worse detection performance due to the loss of sensing information but has the main advantage of smaller communication costs. To get a tradeoff between communication costs and detection performance, we propose a soft-hard combination decision fusion scheme for the clustered distributed detection system with multiple sensors and non-ideal communication channels. A clustered distributed detection system is configured by a fuzzy logic system and a fuzzy c-means clustering algorithm. In clusters, each local sensor transmits its local multiple-bit soft decision to its corresponding cluster head (CH) under the non-ideal channel, in which a simple and efficient soft decision fusion method is used. Between clusters, the fusion center combines all cluster heads' one-bit hard decisions into a final global decision by using an optimal fusion rule. We show that the clustered distributedsystem with the proposed scheme has a good performance that is close to that of the centralized system, but it consumes much less energy than the centralized system at the same time. In addition, the system with the proposed scheme significantly outperforms the conventional distributed detection system that only uses a hard decision fusion. Using simulation results, we also show that the detection performance increases when more bits are delivered in the soft decision in the distributed detection system.
With continuous further development of cable television technology, the integrating and intelligent degree of digital TV network increases constantly. And people are paying more and more attention to issues such as th...
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With continuous further development of cable television technology, the integrating and intelligent degree of digital TV network increases constantly. And people are paying more and more attention to issues such as the stability, reliability, maintainability, security, detectability, life cycle cost, etc. which may provide favorable conditions for the generation and development of prognostic and health management (PHM) of the network equipment. In this paper, the background knowledge of the distributed digital TV signals detectionsystem was illustrated simply at first, and then the basic concept, function and current situation of PHM were introduced. On that basis, the system design of PHM was reflected from system structure and functional component by aiming at realizing this project. In the end, the equipment health examination module has been designed specifically from the operating principle, module composition, function realizing process and decision- making support.
Most reliability models are associated with their own parameters which are typically estimated from the history data. For the widely used distributed detection system in fault detection, the system reliability depends...
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Most reliability models are associated with their own parameters which are typically estimated from the history data. For the widely used distributed detection system in fault detection, the system reliability depends on the number of normally working detectors and the accuracy of its local detectors. Parameters of the reliability model of distributed detection system are subject to random variation as the detectionsystem may be used in different purposes and environments. Hence, to evaluate the reliability accurately, it is necessary to obtain the system parameters precisely from the test data we have. In this paper, we present a Bayesian approach to estimate the unknown parameters of distributed detection system from the scarce data and quantify the uncertainty on the system reliability by measure of variance. A simulation is conducted as well to calculate the effect on the system reliability from the uncertainty of the parameters. An example is applied to illustrate the parameter estimation by Bayesian approach.
The reliability and security of distributed detection systems have become increasingly important due to their growing prevalence in various applications. As advancements in human-machine systems continue, human factor...
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The reliability and security of distributed detection systems have become increasingly important due to their growing prevalence in various applications. As advancements in human-machine systems continue, human factors, such as herding behaviors, are becoming influential in decision fusion process of these systems. The presence of malicious users further highlights the necessity to mitigate security concerns. In this paper, we propose a maximum entropy attack exploring the herding behaviors of users to amplify the hazard of attackers. Different from prior works that try to maximize the fusion error rate, the proposed attack maximizes the entropy of inferred system states from the fusion center, making the fusion results the same as a random coin toss. Moreover, we design static and dynamic attack modes to maximize the entropy of fusion results at the steady state and during the dynamic evolution stage, respectively. Simulation results show that the proposed attack strategy can cause the fusion accuracy to hover around 50% and existing fusion rules cannot resist our proposed attack, demonstrating its effectiveness.
An Amplified DNS DDoS (ADD) attack involves tens of thousands of DNS resolvers that send huge volumes of amplified DNS responses to a single victim host, quickly flooding the victim's network bandwidth. Because AD...
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ISBN:
(纸本)9781509009909
An Amplified DNS DDoS (ADD) attack involves tens of thousands of DNS resolvers that send huge volumes of amplified DNS responses to a single victim host, quickly flooding the victim's network bandwidth. Because ADD attacks are distributed, it is difficult for individual DNS resolvers to detect them based on local DNS query rates alone. Even if a victim detects an ADD attack, it cannot stop the attacker from flooding its network bandwidth. To address this problem, we present a novel mitigation system called "distributed Rate Sharing based Amplified DNS-DDoS Attack Mitigation" (DRS-ADAM). DRS-ADAM facilitates DNS query rate sharing between DNS resolvers that are involved in an attack to detect and completely stop an ADD attack. Each DNS resolver quickly builds the global DNS query rate for potential victims by accumulating the shared rate values, and uses that global rate to make mitigation decisions locally. DRS-ADAM can be easily deployed through a small software update on resolvers and victim hosts, and does not require any additional server component. Our simulation results show that DRS-ADAM can contain the peak attack rates close to a victim's acceptable threshold values (which are far smaller than their sustainable bandwidth) at all times, regardless of the number of resolvers involved in ADD attacks. ADD attacks can be fully mitigated within a few seconds.
At present, the distributed detection system based on Bragg grating as sensor has become a hot spot at home and abroad due to its high precision, good long-term stability and easy detection. In ordering to improve the...
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ISBN:
(纸本)9781510623354
At present, the distributed detection system based on Bragg grating as sensor has become a hot spot at home and abroad due to its high precision, good long-term stability and easy detection. In ordering to improve the grating multiplexing capacity in grating sensor array, this paper proposes a new distributed the weak reflected Bragg grating temperature sensing network. The system is mainly composed of light source module, photoelectric conversion module, data acquisition module and data processing module, which combine the wavelength division multiplexing (WDM) with optical time-domain reflectometer (OTDR). And it has achieved simultaneous online monitoring of weak gratings at various central wavelengths through its homemade tunable multiwavelength light source. Due to the principle of grating reflection, the detection cycle of the system is about 1s without energy accumulation, shorter than the traditional sensing system. Because of using the OTDR, it can break through the limitation of light scanning bandwidth, and its single-channel measurement can be up to kilometers. As above, the system has many advantages, such as good real-time performance, large capacity, short response time, being able to adapt to a variety of work environment, etc.
Object detection and tracking using visual sensors is a critical component of surveillance systems, which presents many challenges. This paper addresses the enhancement of object detection and tracking via the combina...
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Object detection and tracking using visual sensors is a critical component of surveillance systems, which presents many challenges. This paper addresses the enhancement of object detection and tracking via the combination of multiple visual sensors. The enhancement method we introduce compensates for missed object detection based on the partial detection of objects by multiple visual sensors. When one detects an object or more visual sensors, the detected object's local positions transformed into a global object position. Local and global information exchange allows a missed local object's position to recover. However, the exchange of the information may degrade the detection and tracking performance by incorrectly recovering the local object position, which propagated by false object detection. Furthermore, local object positions corresponding to an identical object can transformed into nonequivalent global object positions because of detection uncertainty such as shadows or other artifacts. We improved the performance by preventing the propagation of false object detection. In addition, we present an evaluation method for the final global object position. The proposed method analyzed and evaluated using case studies.
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