Aiming at the suppression of enemy air defense(SEAD)task under the complex and complicated combat sce-nario,the spatiotemporal cooperative path planning methods are studied in this paper.The major research contents in...Aiming at the suppression of enemy air defense(SEAD)task under the complex and complicated combat sce-nario,the spatiotemporal cooperative path planning methods are studied in this paper.The major research contents include opti-mal path points generation,path smoothing and cooperative rendezvous.In the path points generation part,the path points availability testing algorithm and the path segments availability testing algorithm are designed,on this foundation,the swarm intelligence-based path point generation algorithm is utilized to generate the optimal path.In the path smoothing part,taking ter-minal attack angle constraint and maneuverability constraint into consideration,the Dubins curve is introduced to smooth the path segments.In cooperative rendezvous part,we take esti-mated time of arrival requirement constraint and flight speed range constraint into consideration,the speed control strategy and flight path control strategy are introduced,further,the decoupling scheme of the circling maneuver and detouring maneuver is designed,in this case,the maneuver ways,maneu-ver point,maneuver times,maneuver path and flight speed are determined.Finally,the simulation experiments are conducted and the acquired results reveal that the time-space cooperation of multiple unmanned aeriel vehicles(UAVs)is effectively real-ized,in this way,the combat situation suppression against the enemy can be realized in SEAD scenarios.展开更多
In order to save energy and make more efficient use of wireless channel, this article puts forward an energy saving cooperative relaying scheme which actuates the cooperative transmis- sion only when the feedback from...In order to save energy and make more efficient use of wireless channel, this article puts forward an energy saving cooperative relaying scheme which actuates the cooperative transmis- sion only when the feedback from the destination indicates failure of the direct transmission. The proposed scheme selects the optimal relay and its corresponding transmission power in each time slot based on channel condition and residual ener- gy with the objective of minimizing energy con- sumption and extending network lifetime. In the study, the f＇mite-state Markov channel model is used to characterize the correlation structure of channel fading in wireless networks, and the pro- cedure of relay selection and transmission power decision is formulated as a M arkov decision process. Numerical and simulation results show that the proposed scheme consumes less energy and prolongs the network lifetime.展开更多
Lichens are unique individuals which have been widely used in traditional medicines. This study was focused on the bioassayguided phytochemical investigation, and bioactivity evaluation on a lichens species, Parmotrem...Lichens are unique individuals which have been widely used in traditional medicines. This study was focused on the bioassayguided phytochemical investigation, and bioactivity evaluation on a lichens species, Parmotrema cooperi. This first bioassaydirected chemical study on P. cooperi has led to the isolation of ethyl heamatomate （1）, atraric acid （2）, ethyl orsellinate （3）, orsellinic acid （4）, lecanoric acid （5）, gyrophoric acid （6）, and licanorin （7）. The structures of 1-7 were mainly elucidated from spectroscopic methods including 1D, and 2D NMR spectroscopy, and mass spectrometry. These compounds were evaluated for their antiglycation, urease, a-chymotrypsin, and β-glucoronidase inhibitory activities. Few of the phenolic compounds showed significant, while most of them showed good inhibition of protein glycation, and urease activities.展开更多
文摘Aiming at the suppression of enemy air defense(SEAD)task under the complex and complicated combat sce-nario,the spatiotemporal cooperative path planning methods are studied in this paper.The major research contents include opti-mal path points generation,path smoothing and cooperative rendezvous.In the path points generation part,the path points availability testing algorithm and the path segments availability testing algorithm are designed,on this foundation,the swarm intelligence-based path point generation algorithm is utilized to generate the optimal path.In the path smoothing part,taking ter-minal attack angle constraint and maneuverability constraint into consideration,the Dubins curve is introduced to smooth the path segments.In cooperative rendezvous part,we take esti-mated time of arrival requirement constraint and flight speed range constraint into consideration,the speed control strategy and flight path control strategy are introduced,further,the decoupling scheme of the circling maneuver and detouring maneuver is designed,in this case,the maneuver ways,maneu-ver point,maneuver times,maneuver path and flight speed are determined.Finally,the simulation experiments are conducted and the acquired results reveal that the time-space cooperation of multiple unmanned aeriel vehicles(UAVs)is effectively real-ized,in this way,the combat situation suppression against the enemy can be realized in SEAD scenarios.
基金The authors would like to thank the reviewers for their de-tailed reviews and constructive comments, which have helped improve the quality of this paper. This work was supported by the National Natural Science Foundation of China under Grant No. 61101107 the Scientific Research and Innovation Plan for the Youth of BUPT under Grant No. 2011RC0305 the National International Science and Technology Cooperation Project under Grant No. 2010DFA11320.
文摘In order to save energy and make more efficient use of wireless channel, this article puts forward an energy saving cooperative relaying scheme which actuates the cooperative transmis- sion only when the feedback from the destination indicates failure of the direct transmission. The proposed scheme selects the optimal relay and its corresponding transmission power in each time slot based on channel condition and residual ener- gy with the objective of minimizing energy con- sumption and extending network lifetime. In the study, the f＇mite-state Markov channel model is used to characterize the correlation structure of channel fading in wireless networks, and the pro- cedure of relay selection and transmission power decision is formulated as a M arkov decision process. Numerical and simulation results show that the proposed scheme consumes less energy and prolongs the network lifetime.
基金the financial support of the Higher Education Commission,Pakistan,through the project entitled"High Resolution X-Ray Analysis of Pharmaceutically Important Enzymes in Complex with Plant-based Inhibitions as basis for Rational Drug Design (20-1364/ R&D/09)"
文摘Lichens are unique individuals which have been widely used in traditional medicines. This study was focused on the bioassayguided phytochemical investigation, and bioactivity evaluation on a lichens species, Parmotrema cooperi. This first bioassaydirected chemical study on P. cooperi has led to the isolation of ethyl heamatomate （1）, atraric acid （2）, ethyl orsellinate （3）, orsellinic acid （4）, lecanoric acid （5）, gyrophoric acid （6）, and licanorin （7）. The structures of 1-7 were mainly elucidated from spectroscopic methods including 1D, and 2D NMR spectroscopy, and mass spectrometry. These compounds were evaluated for their antiglycation, urease, a-chymotrypsin, and β-glucoronidase inhibitory activities. Few of the phenolic compounds showed significant, while most of them showed good inhibition of protein glycation, and urease activities.
