The Gamma-Ray Monitor （GRM） is a high energy detector onboard the future Chinese-French satellite named the Space-based multi-band astronomical Variable Object Monitor which is dedicated to studies of gamma-ray burs...The Gamma-Ray Monitor （GRM） is a high energy detector onboard the future Chinese-French satellite named the Space-based multi-band astronomical Variable Object Monitor which is dedicated to studies of gamma-ray bursts （GRBs）. This paper presents an investigation of the algorithms that look for GRBs by searching for a significant increase in the photon count rate for the computer onboard GRM. The trigger threshold and trigger efficiency, which are based on a given sample of GRBs, are calculated with the algorithms. The trigger characteristics of onboard instruments GRM and ECLAIRs are also analyzed. In addition, the impact of solar flares on GRM is estimated, and a method to distinguish solar flares from GRBs is investigated.展开更多
With the recent development of digital Micro Electro Mechanical System （MEMS） sensors, the cost of monitoring and detecting seismic events in real time can be greatly reduced. Ability of MEMS accelerograph to record...With the recent development of digital Micro Electro Mechanical System （MEMS） sensors, the cost of monitoring and detecting seismic events in real time can be greatly reduced. Ability of MEMS accelerograph to record a seismic event depends upon the efficiency of triggering algorithm, apart from the sensor＇s sensitivity. There are several classic triggering algorithms developed to detect seismic events, ranging from basic amplitude threshold to more sophisticated pattern recognition. Algorithms based on STA/LTA are reported to be computationally efficient for real time monitoring. In this paper, we analyzed several STA/LTA algorithms to check their efficiency and suitability using data obtained from the Quake Catcher Network （network of MEMS accelerometer stations）. We found that most of the STA/LTA algorithms are suitable for use with MEMS accelerometer data to accurately detect seismic events. However, the efficiency of any particular algorithm is found to be dependent on the parameter set used （i.e., window width of STA, LTA and threshold level）.展开更多
To reduce the potential signaling traffic in IP multimedia subsystem （IMS）, the session establishment procedures were investigated. The serving call session eontrol function （S-CSCF） is the major bottleneck in IMS...To reduce the potential signaling traffic in IP multimedia subsystem （IMS）, the session establishment procedures were investigated. The serving call session eontrol function （S-CSCF） is the major bottleneck in IMS and the existing 3GPP service triggering algorithm （STA） based on initial filter eriteria （iFC） increases the end-to-end session setup delay remarkably. To reduce the session setup delay and improve the system performanee, a SIP response message based filter criteria （rFC） was proposed. Based on the rFC, a SIP response message based STA （RSTA） was further proposed. The modeling and theoretical analysis of 3GPP STA and RSTA were presented. Simulation results show that, compared with 3GPP STA, the RSTA can avoid the additional signaling traffie load of the S-CSCF and application server （AS） effectively, reduce the session setup delay eonsiderably, increase the throughput of the S-CSCF and improve the quality of service （QoS） of IMS network.展开更多
Traditional scheduling algorithms for avionics communication have the shortcoming of messages accumulation,the efficiency and reliability of the service can be improved by combining the distributed integrated modular ...Traditional scheduling algorithms for avionics communication have the shortcoming of messages accumulation,the efficiency and reliability of the service can be improved by combining the distributed integrated modular avionics(DIMA)system with a time trigger mechanism.To further improve the utilization of system resources,the static scheduling algorithm of time triggered service is studied.By making the time trigger message schedule dispersedly,the stabilities of both the available time slots for the event triggered messages and the system will be improved.An improved two-dimensional bin packing algorithm is also presented to achieve the above-mentioned purpose with an extra benefit of better delay performance.展开更多
Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed conve...Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed convex optimization problem with time-varying delays and switching topologies in the case of directed graph topology is studied. The event-triggered communication mechanism is adopted, that is, the communication between agents is determined by the trigger conditions, and the information exchange is carried out only when the conditions are met. Compared with continuous communication, this greatly saves network resources and reduces communication cost. Using Lyapunov-Krasovskii function method and inequality analysis, a new sufficient condition is proposed to ensure that the agent state finally reaches the optimal state. The upper bound of the maximum allowable delay is given. In addition, Zeno behavior will be proved not to exist during the operation of the algorithm. Finally, a simulation example is given to illustrate the correctness of the results in this paper.展开更多
针对复杂环境下四旋翼无人机三维航迹规划问题,提出了一种改进的事件触发灰狼优化算法(event triggered grey wolf optimization,ETGWO)。引入球面矢量刻画飞行路径的生成,通过减少搜索空间提升搜索能力;设计自适应权重动态调整飞行航...针对复杂环境下四旋翼无人机三维航迹规划问题,提出了一种改进的事件触发灰狼优化算法(event triggered grey wolf optimization,ETGWO)。引入球面矢量刻画飞行路径的生成,通过减少搜索空间提升搜索能力;设计自适应权重动态调整飞行航迹成本适应度函数,以提高航迹规划效率和准确性;在灰狼优化算法(grey wolf optimization,GWO)基础上,选择使用改进的非线性收敛因子,提升算法的鲁棒性;为了更好地平衡算法的全局搜索和局部搜索能力,通过引入基于事件触发机制的灰狼个体位置更新速度来改进GWO算法的位置更新策略。仿真对比实验表明,所提出ETGWO算法在四旋翼无人机(quadrotor unmanned aerial vehicles,QUAV)飞行航迹规划方面具有更优越的性能。展开更多
In view of DC speed control system, this paper presents a predictive control algorithm to replace traditional PID control. System predictive model requires little information of the controlled object, and because it...In view of DC speed control system, this paper presents a predictive control algorithm to replace traditional PID control. System predictive model requires little information of the controlled object, and because it adopts rolling optimum method, system展开更多
Coseismic stress-triggering is becoming a new hot spot of research. Coseismic strain steps recorded by borehole strainmeters are particularly valuable in studying coseismic stress-triggered fault slips. Based on the t...Coseismic stress-triggering is becoming a new hot spot of research. Coseismic strain steps recorded by borehole strainmeters are particularly valuable in studying coseismic stress-triggered fault slips. Based on the theory of dis location, one can invert the triggered fault slips with such data if he/she has a well understanding about the local faults. Genetic algorithm can be applied to significantly raise the efficiency of searching a best solution among all possibilities in this kind of inversion. A testifying check of the program and analyses of each parameter＇s influence may further enhance the reliability of inversion results. Taking complexity of geological structure into account, the inversion results should be regarded as the predominant property or a comprehensive effect of triggered local faults＇ activities. As an attempt, we inverted the assumingly active faults＇ slips triggered by the Ms=8.1 Kunlun Mountain earthquake over Beijing area.展开更多
在交直流混合微电网中,并联互联变流器(parallel bidirectional power converters,BPCs)可以实现大容量的功率传输,以满足新型电力系统在空间上的供需匹配。如何在占用更少资源的同时协调控制BPCs实现功率的比例共享,是交直流混合微电网...在交直流混合微电网中,并联互联变流器(parallel bidirectional power converters,BPCs)可以实现大容量的功率传输,以满足新型电力系统在空间上的供需匹配。如何在占用更少资源的同时协调控制BPCs实现功率的比例共享,是交直流混合微电网中BPCs控制的研究难点。因此,该文设计了一种针对BPCs的事件触发改进一致性协调控制策略。以归一化下垂控制为基础,提出了改进的比例功率一致性算法,实现BPCs间高精度比例功率共享。在此之上,基于BPCs比例功率误差建立事件触发改进一致性算法,并预设触发函数的预判阈值,从而降低系统在稳定状态下的通信次数。最后进行仿真对比分析,结果表明该文提出的方法相比基本一致性算法通信量减少98.35%;同时,与现有控制策略相比,该文提出的方法有着更好的控制性能。展开更多
基金Supported by the National Natural Science Foundation of China
文摘The Gamma-Ray Monitor （GRM） is a high energy detector onboard the future Chinese-French satellite named the Space-based multi-band astronomical Variable Object Monitor which is dedicated to studies of gamma-ray bursts （GRBs）. This paper presents an investigation of the algorithms that look for GRBs by searching for a significant increase in the photon count rate for the computer onboard GRM. The trigger threshold and trigger efficiency, which are based on a given sample of GRBs, are calculated with the algorithms. The trigger characteristics of onboard instruments GRM and ECLAIRs are also analyzed. In addition, the impact of solar flares on GRM is estimated, and a method to distinguish solar flares from GRBs is investigated.
基金IIT Roorkee under the Faculty Initiation Grant No.100556
文摘With the recent development of digital Micro Electro Mechanical System （MEMS） sensors, the cost of monitoring and detecting seismic events in real time can be greatly reduced. Ability of MEMS accelerograph to record a seismic event depends upon the efficiency of triggering algorithm, apart from the sensor＇s sensitivity. There are several classic triggering algorithms developed to detect seismic events, ranging from basic amplitude threshold to more sophisticated pattern recognition. Algorithms based on STA/LTA are reported to be computationally efficient for real time monitoring. In this paper, we analyzed several STA/LTA algorithms to check their efficiency and suitability using data obtained from the Quake Catcher Network （network of MEMS accelerometer stations）. We found that most of the STA/LTA algorithms are suitable for use with MEMS accelerometer data to accurately detect seismic events. However, the efficiency of any particular algorithm is found to be dependent on the parameter set used （i.e., window width of STA, LTA and threshold level）.
基金Supported by National Science Fund for Distinguished Young Scholars (No. 60525110)National Basic Research Program of China (No.2007CB307100, 2007CB307103)+1 种基金Program for New Century Excellent Talents in University (No. NCET-04-0111 )Development Fund Project for Electronic and Information Industry (Mobile Service and Application System Based on 3G)
文摘To reduce the potential signaling traffic in IP multimedia subsystem （IMS）, the session establishment procedures were investigated. The serving call session eontrol function （S-CSCF） is the major bottleneck in IMS and the existing 3GPP service triggering algorithm （STA） based on initial filter eriteria （iFC） increases the end-to-end session setup delay remarkably. To reduce the session setup delay and improve the system performanee, a SIP response message based filter criteria （rFC） was proposed. Based on the rFC, a SIP response message based STA （RSTA） was further proposed. The modeling and theoretical analysis of 3GPP STA and RSTA were presented. Simulation results show that, compared with 3GPP STA, the RSTA can avoid the additional signaling traffie load of the S-CSCF and application server （AS） effectively, reduce the session setup delay eonsiderably, increase the throughput of the S-CSCF and improve the quality of service （QoS） of IMS network.
基金Supported by Joint Fundation for Equipment Pre-research of Aerospace Science and Technology
文摘Traditional scheduling algorithms for avionics communication have the shortcoming of messages accumulation,the efficiency and reliability of the service can be improved by combining the distributed integrated modular avionics(DIMA)system with a time trigger mechanism.To further improve the utilization of system resources,the static scheduling algorithm of time triggered service is studied.By making the time trigger message schedule dispersedly,the stabilities of both the available time slots for the event triggered messages and the system will be improved.An improved two-dimensional bin packing algorithm is also presented to achieve the above-mentioned purpose with an extra benefit of better delay performance.
文摘Nowadays, distributed optimization algorithms are widely used in various complex networks. In order to expand the theory of distributed optimization algorithms in the direction of directed graph, the distributed convex optimization problem with time-varying delays and switching topologies in the case of directed graph topology is studied. The event-triggered communication mechanism is adopted, that is, the communication between agents is determined by the trigger conditions, and the information exchange is carried out only when the conditions are met. Compared with continuous communication, this greatly saves network resources and reduces communication cost. Using Lyapunov-Krasovskii function method and inequality analysis, a new sufficient condition is proposed to ensure that the agent state finally reaches the optimal state. The upper bound of the maximum allowable delay is given. In addition, Zeno behavior will be proved not to exist during the operation of the algorithm. Finally, a simulation example is given to illustrate the correctness of the results in this paper.
文摘针对复杂环境下四旋翼无人机三维航迹规划问题,提出了一种改进的事件触发灰狼优化算法(event triggered grey wolf optimization,ETGWO)。引入球面矢量刻画飞行路径的生成,通过减少搜索空间提升搜索能力;设计自适应权重动态调整飞行航迹成本适应度函数,以提高航迹规划效率和准确性;在灰狼优化算法(grey wolf optimization,GWO)基础上,选择使用改进的非线性收敛因子,提升算法的鲁棒性;为了更好地平衡算法的全局搜索和局部搜索能力,通过引入基于事件触发机制的灰狼个体位置更新速度来改进GWO算法的位置更新策略。仿真对比实验表明,所提出ETGWO算法在四旋翼无人机(quadrotor unmanned aerial vehicles,QUAV)飞行航迹规划方面具有更优越的性能。
文摘In view of DC speed control system, this paper presents a predictive control algorithm to replace traditional PID control. System predictive model requires little information of the controlled object, and because it adopts rolling optimum method, system
基金National Natural Science Foundation of China (40374011) and Joint Seismological Science of China (1040037).
文摘Coseismic stress-triggering is becoming a new hot spot of research. Coseismic strain steps recorded by borehole strainmeters are particularly valuable in studying coseismic stress-triggered fault slips. Based on the theory of dis location, one can invert the triggered fault slips with such data if he/she has a well understanding about the local faults. Genetic algorithm can be applied to significantly raise the efficiency of searching a best solution among all possibilities in this kind of inversion. A testifying check of the program and analyses of each parameter＇s influence may further enhance the reliability of inversion results. Taking complexity of geological structure into account, the inversion results should be regarded as the predominant property or a comprehensive effect of triggered local faults＇ activities. As an attempt, we inverted the assumingly active faults＇ slips triggered by the Ms=8.1 Kunlun Mountain earthquake over Beijing area.
文摘在交直流混合微电网中,并联互联变流器(parallel bidirectional power converters,BPCs)可以实现大容量的功率传输,以满足新型电力系统在空间上的供需匹配。如何在占用更少资源的同时协调控制BPCs实现功率的比例共享,是交直流混合微电网中BPCs控制的研究难点。因此,该文设计了一种针对BPCs的事件触发改进一致性协调控制策略。以归一化下垂控制为基础,提出了改进的比例功率一致性算法,实现BPCs间高精度比例功率共享。在此之上,基于BPCs比例功率误差建立事件触发改进一致性算法,并预设触发函数的预判阈值,从而降低系统在稳定状态下的通信次数。最后进行仿真对比分析,结果表明该文提出的方法相比基本一致性算法通信量减少98.35%;同时,与现有控制策略相比,该文提出的方法有着更好的控制性能。
