Landslides distribute extensively in Rongxian county, the southeast of Guangxi province, China and pose great threats to this county. At present, hazard management strategy is facing an unprecedented challenge due to ...Landslides distribute extensively in Rongxian county, the southeast of Guangxi province, China and pose great threats to this county. At present, hazard management strategy is facing an unprecedented challenge due to lack of a landslide susceptibility map. Therefore, the purpose of this paper was to construct a landslide susceptibility map by adopting three widely used models based on an integrated understanding of landslide’s characteristics.These models include a semi-quantitative method(SQM), information value model(IVM) and logistical regression model(LRM).The primary results show that(1) the county is classified into four susceptive regions, named as very low, low, moderate and high, which covered an area of 13.43%, 32.40%, 31.19% and 22.99% in SQM, 0.86%, 26.82%, 44.11%, and 28.21% in IVM, 9.88%, 17.73%, 46.36% and 26.03% in LRM;(2) landslides are likely to occur within the areas characterized by following obvious aspects: high intensity of human activities, slope angles of 25°～35°, the thickness of weathered soil is larger than 15 m; the lithology is granite, shale and mud rock;(3) the area under the curve of SQM, IVM and LRM is 0.7151, 0.7688 and 0.7362 respectively, and the corresponding success rate is 71.51%, 76.88% and 73.62%. It is concluded that these three models are acceptable because they have an effective capability of susceptibility assessment and can achieve an expected accuracy. In addition, the susceptibility outcome obtained from IVM provides a slightly higher quality than that from SQM, LRM.展开更多
In this paper, we investigate the cooperative strategy with total power constraint in decode-and-forward （DF） relaying scenario, in the presence of an eavesdropper. Due to the difference of channel for each source-r...In this paper, we investigate the cooperative strategy with total power constraint in decode-and-forward （DF） relaying scenario, in the presence of an eavesdropper. Due to the difference of channel for each source-relay link, not all relay nodes have constructive impacts on the achievable secrecy rate. Besides, the final achieved secrecy rate depends on both source-relay and relay-destination links in DF relaying scenario. Therefore, the principal question here is how to select cooperative strategy among relays with proper power allocation to maximize the secrecy rate. Three strategies are considered in this paper. First, we investigate the cooperative jamming （CJ） strategy, where one relay with achieved target transmission rate is selected as a conventional relay forwarding signal, and remaining relays generate artificial noise via CJ strategy to disrupt the eavesdropper. Two CJ schemes with closed-form solutions, optimal cooperative jamming （OCJ） and null space cooperative jamming （NSCJ）, are proposed. With these solutions, the corresponding power allocation is formulated as a geometric programming （GP） problem and solved efficiently by convex programming technique. Then, to exploit the cooperative diversity, we investigate the cooperative relaying （CR） strategy. An iterative algorithm using semi-definite programming （SDP） and GP together with bisection search method is proposed to optimize the cooperative relaying weight and power allocated to the source and relays. Furthermore, to exploit the advantages of both CR and CJ, we propose an adaptive strategy to enhance the security. Simulation results demonstrate that the efficiency of the proposed cooperative strategies in terms of secrecy rate.展开更多
基金funded by the National Natural Science Foundation of China (No. 51609041)the Natural Scientific Project of Guangxi Zhuang Autonomous Region (No. 2018GXNSFAA138187)+2 种基金the Project of the Education Department of Guangxi Zhuang Autonomous Region (No. 2018KY0027)the Project of Department of Land and Resources of Guangxi Zhuang Autonomous Region (GXZC2018G3-19302-JGYZ)the Project of Xi’an Geological survey center of China Geological survey (DD20189270)
文摘Landslides distribute extensively in Rongxian county, the southeast of Guangxi province, China and pose great threats to this county. At present, hazard management strategy is facing an unprecedented challenge due to lack of a landslide susceptibility map. Therefore, the purpose of this paper was to construct a landslide susceptibility map by adopting three widely used models based on an integrated understanding of landslide’s characteristics.These models include a semi-quantitative method(SQM), information value model(IVM) and logistical regression model(LRM).The primary results show that(1) the county is classified into four susceptive regions, named as very low, low, moderate and high, which covered an area of 13.43%, 32.40%, 31.19% and 22.99% in SQM, 0.86%, 26.82%, 44.11%, and 28.21% in IVM, 9.88%, 17.73%, 46.36% and 26.03% in LRM;(2) landslides are likely to occur within the areas characterized by following obvious aspects: high intensity of human activities, slope angles of 25°～35°, the thickness of weathered soil is larger than 15 m; the lithology is granite, shale and mud rock;(3) the area under the curve of SQM, IVM and LRM is 0.7151, 0.7688 and 0.7362 respectively, and the corresponding success rate is 71.51%, 76.88% and 73.62%. It is concluded that these three models are acceptable because they have an effective capability of susceptibility assessment and can achieve an expected accuracy. In addition, the susceptibility outcome obtained from IVM provides a slightly higher quality than that from SQM, LRM.
基金supported by the National Key Technology R&D Program of China(2012ZX03004005)the Foundational Research Funds for the Central Universities
文摘In this paper, we investigate the cooperative strategy with total power constraint in decode-and-forward （DF） relaying scenario, in the presence of an eavesdropper. Due to the difference of channel for each source-relay link, not all relay nodes have constructive impacts on the achievable secrecy rate. Besides, the final achieved secrecy rate depends on both source-relay and relay-destination links in DF relaying scenario. Therefore, the principal question here is how to select cooperative strategy among relays with proper power allocation to maximize the secrecy rate. Three strategies are considered in this paper. First, we investigate the cooperative jamming （CJ） strategy, where one relay with achieved target transmission rate is selected as a conventional relay forwarding signal, and remaining relays generate artificial noise via CJ strategy to disrupt the eavesdropper. Two CJ schemes with closed-form solutions, optimal cooperative jamming （OCJ） and null space cooperative jamming （NSCJ）, are proposed. With these solutions, the corresponding power allocation is formulated as a geometric programming （GP） problem and solved efficiently by convex programming technique. Then, to exploit the cooperative diversity, we investigate the cooperative relaying （CR） strategy. An iterative algorithm using semi-definite programming （SDP） and GP together with bisection search method is proposed to optimize the cooperative relaying weight and power allocated to the source and relays. Furthermore, to exploit the advantages of both CR and CJ, we propose an adaptive strategy to enhance the security. Simulation results demonstrate that the efficiency of the proposed cooperative strategies in terms of secrecy rate.
