The physical properties of a reliable acoustic path （RAP） are analysed and subsequently a weighted-subspace~ fitting matched field （WSF-MF） method for passive localization is presented by exploiting the properties...The physical properties of a reliable acoustic path （RAP） are analysed and subsequently a weighted-subspace~ fitting matched field （WSF-MF） method for passive localization is presented by exploiting the properties of the RAP environment. The RAP is an important acoustic duct in the deep ocean, which occurs when the receiver is placed near the bottom where the sound velocity exceeds the maximum sound velocity in the vicinity of the surface. It is found that in the RAP environment the transmission loss is rather low and no blind zone of surveillance exists in a medium range. The ray theory is used to explain these phenomena. Furthermore, the analysis of the arrival structures shows that the source localization method based on arrival angle is feasible in this environment. However, the conventional methods suffer from the complicated and inaccurate estimation of the arrival angle. In this paper, a straightforward WSF-MF method is derived to exploit the information about the arrival angles indirectly. The method is to minimize the distance between the signal subspace and the spanned space by the array manifold in a finite range-depth space rather than the arrival-angle space. Simulations are performed to demonstrate the features of the method, and the results are explained by the arrival structures in the RAP environment.展开更多
Consideration of the travel time variation for rescue vehicles is significant in the field of emergency management research.Because of uncertain factors,such as the weather or OD(origin-destination)variations caused b...Consideration of the travel time variation for rescue vehicles is significant in the field of emergency management research.Because of uncertain factors,such as the weather or OD(origin-destination)variations caused by traffic accidents,travel time is a random variable.In emergency situations,it is particularly necessary to determine the optimal reliable route of rescue vehicles from the perspective of uncertainty.This paper first proposes an optimal reliable path finding(ORPF)model for rescue vehicles,which considers the uncertainties of travel time,and link correlations.On this basis,it investigates how to optimize rescue vehicle allocation to minimize rescue time,taking into account travel time reliability under uncertain conditions.Because of the non-additive property of the objective function,this paper adopts a heuristic algorithm based on the K-shortest path algorithm,and inequality techniques to tackle the proposed modified integer programming model.Finally,the numerical experiments are presented to verify the accuracy and effectiveness of the proposed model and algorithm.The results show that ignoring travel time reliability may lead to an over-or under-estimation of the effective travel time of rescue vehicles on a particular path,and thereby an incorrect allocation scheme.展开更多
In China’s current educational fiscal decision making,problems are as follows:no law to trust or not abiding by available laws,absence of equity and efficiency,as well as the standardization of decision-making proced...In China’s current educational fiscal decision making,problems are as follows:no law to trust or not abiding by available laws,absence of equity and efficiency,as well as the standardization of decision-making procedures.It is necessary to set up effective fiscal decision-making mechanism in education and rationally devise reliable paths.展开更多
Mobile ad hoc networks(MANETs),which correspond to a novel wireless technology,are widely used in Internet of Things(IoT)systems such as drones,wireless sensor networks,and military or disaster relief communication.Fr...Mobile ad hoc networks(MANETs),which correspond to a novel wireless technology,are widely used in Internet of Things(IoT)systems such as drones,wireless sensor networks,and military or disaster relief communication.From the perspective of communication and data collection,the success rate of collaborations between nodes in mobile ad hoc networks and reliability of data collection mainly depend on whether the nodes in the network operate normally,namely,according to the established network rules.However,mobile ad hoc networks are vulnerable to attacks targeting transmission channels and nodes owing to their dynamic evolution,openness,and distributed characteristics.Therefore,during the network operation,it is necessary to classify and detect the behavior and characteristics of each node.However,most existing research only analyzes and considers responses against a single or small number of attacks.To address these issues,this article first systematically analyzed and classified common active attacks in MANETs.Then,a node trust model was proposed based on the characteristics of various attacks;subsequently,a new secure routing protocol,namely,TC-AODV,was proposed.This protocol has minimal effect on the original communication dynamics and can effectively deal with Packet drop,wormhole,Session hijacking,and other main attacks in MANETs.The NS3 simulation results show that the proposed routing protocol attains good transmission performance,can effectively identify various attacks and bypass malicious nodes,and securely complete the communication process.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11174235 and 61101192)the Science and Technology Development Project of Shaanxi Province,China(Grant No.2010KJXX-02)+2 种基金the Program for New Century Excellent Talents in University,China(Grant No.NCET-08-0455)the Foundation of State Key Lab of Acoustics,China(Grant No.SKLOA201101)the Doctorate Foundation of Northwestern Polytechnical University,China(Grant No.CX201226)
文摘The physical properties of a reliable acoustic path （RAP） are analysed and subsequently a weighted-subspace~ fitting matched field （WSF-MF） method for passive localization is presented by exploiting the properties of the RAP environment. The RAP is an important acoustic duct in the deep ocean, which occurs when the receiver is placed near the bottom where the sound velocity exceeds the maximum sound velocity in the vicinity of the surface. It is found that in the RAP environment the transmission loss is rather low and no blind zone of surveillance exists in a medium range. The ray theory is used to explain these phenomena. Furthermore, the analysis of the arrival structures shows that the source localization method based on arrival angle is feasible in this environment. However, the conventional methods suffer from the complicated and inaccurate estimation of the arrival angle. In this paper, a straightforward WSF-MF method is derived to exploit the information about the arrival angles indirectly. The method is to minimize the distance between the signal subspace and the spanned space by the array manifold in a finite range-depth space rather than the arrival-angle space. Simulations are performed to demonstrate the features of the method, and the results are explained by the arrival structures in the RAP environment.
基金Projects(72071202,71671184)supported by the National Natural Science Foundation of ChinaProject(22YJCZH144)supported by Humanities and Social Sciences Youth Foundation,Ministry of Education of China+3 种基金Project(2022M712680)supported by Postdoctoral Research Foundation of ChinaProject(22KJB110027)supported by Natural Science Foundation of Colleges and Universities in Jiangsu Province,ChinaProject(D2019046)supported by Initiation Foundation of Xuzhou Medical University,ChinaProject(2021SJA1079)supported by General Project of Philosophy and Social Science Research in Jiangsu Universities,China。
文摘Consideration of the travel time variation for rescue vehicles is significant in the field of emergency management research.Because of uncertain factors,such as the weather or OD(origin-destination)variations caused by traffic accidents,travel time is a random variable.In emergency situations,it is particularly necessary to determine the optimal reliable route of rescue vehicles from the perspective of uncertainty.This paper first proposes an optimal reliable path finding(ORPF)model for rescue vehicles,which considers the uncertainties of travel time,and link correlations.On this basis,it investigates how to optimize rescue vehicle allocation to minimize rescue time,taking into account travel time reliability under uncertain conditions.Because of the non-additive property of the objective function,this paper adopts a heuristic algorithm based on the K-shortest path algorithm,and inequality techniques to tackle the proposed modified integer programming model.Finally,the numerical experiments are presented to verify the accuracy and effectiveness of the proposed model and algorithm.The results show that ignoring travel time reliability may lead to an over-or under-estimation of the effective travel time of rescue vehicles on a particular path,and thereby an incorrect allocation scheme.
文摘In China’s current educational fiscal decision making,problems are as follows:no law to trust or not abiding by available laws,absence of equity and efficiency,as well as the standardization of decision-making procedures.It is necessary to set up effective fiscal decision-making mechanism in education and rationally devise reliable paths.
基金supported in part by the National Key Research and Development Project of China(2019YFB2102303)the National Natural Science Foundation of China(61971014).
文摘Mobile ad hoc networks(MANETs),which correspond to a novel wireless technology,are widely used in Internet of Things(IoT)systems such as drones,wireless sensor networks,and military or disaster relief communication.From the perspective of communication and data collection,the success rate of collaborations between nodes in mobile ad hoc networks and reliability of data collection mainly depend on whether the nodes in the network operate normally,namely,according to the established network rules.However,mobile ad hoc networks are vulnerable to attacks targeting transmission channels and nodes owing to their dynamic evolution,openness,and distributed characteristics.Therefore,during the network operation,it is necessary to classify and detect the behavior and characteristics of each node.However,most existing research only analyzes and considers responses against a single or small number of attacks.To address these issues,this article first systematically analyzed and classified common active attacks in MANETs.Then,a node trust model was proposed based on the characteristics of various attacks;subsequently,a new secure routing protocol,namely,TC-AODV,was proposed.This protocol has minimal effect on the original communication dynamics and can effectively deal with Packet drop,wormhole,Session hijacking,and other main attacks in MANETs.The NS3 simulation results show that the proposed routing protocol attains good transmission performance,can effectively identify various attacks and bypass malicious nodes,and securely complete the communication process.
