In this paper,an integrated estimation guidance and control(IEGC)system is designed based on the command filtered backstepping approach for circular field-of-view(FOV)strapdown missiles.The threedimensional integrated...In this paper,an integrated estimation guidance and control(IEGC)system is designed based on the command filtered backstepping approach for circular field-of-view(FOV)strapdown missiles.The threedimensional integrated estimation guidance and control nonlinear model with limited actuator deflection angle is established considering the seeker's FOV constraint.The boundary time-varying integral barrier Lyapunov function(IBLF)is employed in backstepping design to constrain the body line-of-sight(BLOS)in IEGC system to fit a circular FOV.Then,the nonlinear adaptive controller is designed to estimate the changing aerodynamic parameters.The generalized extended state observer(GESO)is designed to estimate the acceleration of the maneuvering targets and the unmatched time-varying disturbances for improving tracking accuracy.Furthermore,the command filters are used to solve the"differential expansion"problem during the backstepping design.The Lyapunov theory is used to prove the stability of the overall closed-loop IEGC system.Finally,the simulation results validate the integrated system's effectiveness,achieving high accuracy strikes against maneuvering targets.展开更多
僵尸网络(Botnet)是一种从传统恶意代码形态进化而来的新型攻击方式,为攻击者提供了隐匿、灵活且高效的一对多命令与控制信道(Command and Control channel,C&C)机制,可以控制大量僵尸主机实现信息窃取、分布式拒绝服务攻击和垃圾...僵尸网络(Botnet)是一种从传统恶意代码形态进化而来的新型攻击方式,为攻击者提供了隐匿、灵活且高效的一对多命令与控制信道(Command and Control channel,C&C)机制,可以控制大量僵尸主机实现信息窃取、分布式拒绝服务攻击和垃圾邮件发送等攻击目的。该文提出一种与僵尸网络结构和C&C协议无关,不需要分析数据包的特征负载的僵尸网络检测方法。该方法首先使用预过滤规则对捕获的流量进行过滤,去掉与僵尸网络无关的流量;其次对过滤后的流量属性进行统计;接着使用基于X-means聚类的两步聚类算法对C&C信道的流量属性进行分析与聚类,从而达到对僵尸网络检测的目的。实验证明,该方法高效准确地把僵尸网络流量与其他正常网络流量区分,达到从实际网络中检测僵尸网络的要求,并且具有较低的误判率。展开更多
Adaptive optimization is one of the means that agile organization of command and control resource （AOC2R） adapts for the dynamic battlefield environment. A math model of the adaptive optimization of AOC2R is put for...Adaptive optimization is one of the means that agile organization of command and control resource （AOC2R） adapts for the dynamic battlefield environment. A math model of the adaptive optimization of AOC2R is put forward by analyzing the interrelating concept and research. The model takes the adaptive process as a multi-stage decision making problem. The 2-phases method is presented to calculate the model, which obtains the related parameters by running the colored Petri net （CPN） model of AOC2R and then searches for the result by ant colony optimization （ACO） algorithm integrated with genetic optimization techniques. The simulation results demonstrate that the proposed algorithm greatly improves the performance of AOC2R.展开更多
The global economic downturn caused primarily by the US sub-prime mortgage crisis in 2007 engendered revenue loss of the multinational corporations. Existing studies have yet to depict the detrimental impacts on city...The global economic downturn caused primarily by the US sub-prime mortgage crisis in 2007 engendered revenue loss of the multinational corporations. Existing studies have yet to depict the detrimental impacts on city＇s command and control functions induced by the sub-prime mortgage crisis together with its residual wave of global economic recession on the global spatial economy. Recent and previous studies have produced an ＇instant history＇ of the global spatial economy before the global economic downturn undermines the global economy in late 2008. How- ever, the waxes and wanes of major cities＇ command and control functions on the global economic arena before and after the outbreak of financial crisis and its associated geo-economic transitions are still poorly understood. This paper attempts to contribute a new set of customized data to update and fill in the gap in the literature with the investigation of the command and control functions of cities arotmd the world from 2005 to 2009. Particular attentions are paid to the time-space relationship of the geo-economic transition that can capture the recent historical images of the com- mand and control situation of different cities in the world.展开更多
With the development of the transportation industry, the effective guidance of aircraft in an emergency to prevent catastrophic accidents remains one of the top safety concerns. Undoubtedly, operational status data of...With the development of the transportation industry, the effective guidance of aircraft in an emergency to prevent catastrophic accidents remains one of the top safety concerns. Undoubtedly, operational status data of the aircraft play an important role in the judgment and command of the Operational Control Center(OCC). However, how to transmit various operational status data from abnormal aircraft back to the OCC in an emergency is still an open problem. In this paper, we propose a novel Telemetry, Tracking,and Command(TT&C) architecture named Collaborative TT&C(CoTT&C) based on mega-constellation to solve such a problem. CoTT&C allows each satellite to help the abnormal aircraft by sharing TT&C resources when needed, realizing real-time and reliable aeronautical communication in an emergency. Specifically, we design a dynamic resource sharing mechanism for CoTT&C and model the mechanism as a single-leader-multi-follower Stackelberg game. Further, we give an unique Nash Equilibrium(NE) of the game as a closed form. Simulation results demonstrate that the proposed resource sharing mechanism is effective, incentive compatible, fair, and reciprocal. We hope that our findings can shed some light for future research on aeronautical communications in an emergency.展开更多
The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used f...The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used for simulating the unreliability of the highly dependable mission system seems not so efficient for the TT＆C mission. The concept about the importance of failure transition is proposed based on the logical relationship between TT＆C mission and its involved resources. Then, the importance is used for readjusting the transition rate of the failure transition when using the forcing and failure biasing during the simulation. Examples show that the improved CFFB method can evidently increase the occurrence of the TT＆C mission failure event and decrease the sample variance. More redundancy of the TT＆C mission leads to the improved CFFB method more efficient.展开更多
In this paper the geographical information system （GIS） is applied to earthquake and tsunami emergency work and an earthquake and tsunami emergency command system （ETECS） for seaside cities is developed which is c...In this paper the geographical information system （GIS） is applied to earthquake and tsunami emergency work and an earthquake and tsunami emergency command system （ETECS） for seaside cities is developed which is composed of a basic database and six subsystems. By employing this system, the responsible municipal departments can make rapid prediction before the occurrence of earthquake or tsunami, make commanding decisions concerning the disaster-fight during the disastrous event, and make rapid estimates of the casualties and economic losses. So that the government could conduct relief work in time and planning for future disaster reduction and prevention.展开更多
GIS assist in specific planning and decision-making processes in irrigation through the input, spatial analysis and output of relevant information. The real strength of GIS is its ability to integrate information. Thi...GIS assist in specific planning and decision-making processes in irrigation through the input, spatial analysis and output of relevant information. The real strength of GIS is its ability to integrate information. This integration power makes the scope of GIS almost infinite. The unique integration capability of GIS allows disparate data sets to be brought together to create a complete picture of a situation. GIS technology illustrates relationships, patterns and connections that are not necessarily obvious in any one data set but are amazingly apparent once the data sets are integrated. GIS also helps us to assess the performance of the irrigation command areas. GIS based system helps a canal to analyze the spatial information about its engineers and farmers to improve planning, management and supply of water resources to its corresponding blocks. In order to manage the water efficiently in the command area, it is needless to say that calculation and evaluation of water demands in detail at block and minor level to be given overriding priority. Blocks and Chak boundaries can be delineated from the Digital Elevation Model using GIS techniques. These boundaries will help to plan and allocate the water resources to improve the water allocation strategies and in turn water use efficiency and can make inter-canal comparisons. The delineated block boundaries can be refined exactly using the drainage, topography and existing canal network in GIS platform.展开更多
文摘In this paper,an integrated estimation guidance and control(IEGC)system is designed based on the command filtered backstepping approach for circular field-of-view(FOV)strapdown missiles.The threedimensional integrated estimation guidance and control nonlinear model with limited actuator deflection angle is established considering the seeker's FOV constraint.The boundary time-varying integral barrier Lyapunov function(IBLF)is employed in backstepping design to constrain the body line-of-sight(BLOS)in IEGC system to fit a circular FOV.Then,the nonlinear adaptive controller is designed to estimate the changing aerodynamic parameters.The generalized extended state observer(GESO)is designed to estimate the acceleration of the maneuvering targets and the unmatched time-varying disturbances for improving tracking accuracy.Furthermore,the command filters are used to solve the"differential expansion"problem during the backstepping design.The Lyapunov theory is used to prove the stability of the overall closed-loop IEGC system.Finally,the simulation results validate the integrated system's effectiveness,achieving high accuracy strikes against maneuvering targets.
文摘僵尸网络(Botnet)是一种从传统恶意代码形态进化而来的新型攻击方式,为攻击者提供了隐匿、灵活且高效的一对多命令与控制信道(Command and Control channel,C&C)机制,可以控制大量僵尸主机实现信息窃取、分布式拒绝服务攻击和垃圾邮件发送等攻击目的。该文提出一种与僵尸网络结构和C&C协议无关,不需要分析数据包的特征负载的僵尸网络检测方法。该方法首先使用预过滤规则对捕获的流量进行过滤,去掉与僵尸网络无关的流量;其次对过滤后的流量属性进行统计;接着使用基于X-means聚类的两步聚类算法对C&C信道的流量属性进行分析与聚类,从而达到对僵尸网络检测的目的。实验证明,该方法高效准确地把僵尸网络流量与其他正常网络流量区分,达到从实际网络中检测僵尸网络的要求,并且具有较低的误判率。
文摘Adaptive optimization is one of the means that agile organization of command and control resource （AOC2R） adapts for the dynamic battlefield environment. A math model of the adaptive optimization of AOC2R is put forward by analyzing the interrelating concept and research. The model takes the adaptive process as a multi-stage decision making problem. The 2-phases method is presented to calculate the model, which obtains the related parameters by running the colored Petri net （CPN） model of AOC2R and then searches for the result by ant colony optimization （ACO） algorithm integrated with genetic optimization techniques. The simulation results demonstrate that the proposed algorithm greatly improves the performance of AOC2R.
基金Foundation item:Under the auspices of Hui Oi Chow Trust Fund(No.200902172004)Mrs.Li Ka Shing Fund,Strategic Research Theme on Contemporary China,Small Project Funding provided by the University of Hong Kong(No.200807176152)
文摘The global economic downturn caused primarily by the US sub-prime mortgage crisis in 2007 engendered revenue loss of the multinational corporations. Existing studies have yet to depict the detrimental impacts on city＇s command and control functions induced by the sub-prime mortgage crisis together with its residual wave of global economic recession on the global spatial economy. Recent and previous studies have produced an ＇instant history＇ of the global spatial economy before the global economic downturn undermines the global economy in late 2008. How- ever, the waxes and wanes of major cities＇ command and control functions on the global economic arena before and after the outbreak of financial crisis and its associated geo-economic transitions are still poorly understood. This paper attempts to contribute a new set of customized data to update and fill in the gap in the literature with the investigation of the command and control functions of cities arotmd the world from 2005 to 2009. Particular attentions are paid to the time-space relationship of the geo-economic transition that can capture the recent historical images of the com- mand and control situation of different cities in the world.
基金supported by the National Natural Science Foundation of China under Grant 62131012/61971261。
文摘With the development of the transportation industry, the effective guidance of aircraft in an emergency to prevent catastrophic accidents remains one of the top safety concerns. Undoubtedly, operational status data of the aircraft play an important role in the judgment and command of the Operational Control Center(OCC). However, how to transmit various operational status data from abnormal aircraft back to the OCC in an emergency is still an open problem. In this paper, we propose a novel Telemetry, Tracking,and Command(TT&C) architecture named Collaborative TT&C(CoTT&C) based on mega-constellation to solve such a problem. CoTT&C allows each satellite to help the abnormal aircraft by sharing TT&C resources when needed, realizing real-time and reliable aeronautical communication in an emergency. Specifically, we design a dynamic resource sharing mechanism for CoTT&C and model the mechanism as a single-leader-multi-follower Stackelberg game. Further, we give an unique Nash Equilibrium(NE) of the game as a closed form. Simulation results demonstrate that the proposed resource sharing mechanism is effective, incentive compatible, fair, and reciprocal. We hope that our findings can shed some light for future research on aeronautical communications in an emergency.
基金supported by the National Natural Science Foundation of China (71071159)
文摘The tracking, telemetry and command （TT＆C） mission is extremely reliable for its characters of small time horizon and high redundancy. The combined forcing and failure biasing （CFFB） method that is usually used for simulating the unreliability of the highly dependable mission system seems not so efficient for the TT＆C mission. The concept about the importance of failure transition is proposed based on the logical relationship between TT＆C mission and its involved resources. Then, the importance is used for readjusting the transition rate of the failure transition when using the forcing and failure biasing during the simulation. Examples show that the improved CFFB method can evidently increase the occurrence of the TT＆C mission failure event and decrease the sample variance. More redundancy of the TT＆C mission leads to the improved CFFB method more efficient.
文摘In this paper the geographical information system （GIS） is applied to earthquake and tsunami emergency work and an earthquake and tsunami emergency command system （ETECS） for seaside cities is developed which is composed of a basic database and six subsystems. By employing this system, the responsible municipal departments can make rapid prediction before the occurrence of earthquake or tsunami, make commanding decisions concerning the disaster-fight during the disastrous event, and make rapid estimates of the casualties and economic losses. So that the government could conduct relief work in time and planning for future disaster reduction and prevention.
文摘GIS assist in specific planning and decision-making processes in irrigation through the input, spatial analysis and output of relevant information. The real strength of GIS is its ability to integrate information. This integration power makes the scope of GIS almost infinite. The unique integration capability of GIS allows disparate data sets to be brought together to create a complete picture of a situation. GIS technology illustrates relationships, patterns and connections that are not necessarily obvious in any one data set but are amazingly apparent once the data sets are integrated. GIS also helps us to assess the performance of the irrigation command areas. GIS based system helps a canal to analyze the spatial information about its engineers and farmers to improve planning, management and supply of water resources to its corresponding blocks. In order to manage the water efficiently in the command area, it is needless to say that calculation and evaluation of water demands in detail at block and minor level to be given overriding priority. Blocks and Chak boundaries can be delineated from the Digital Elevation Model using GIS techniques. These boundaries will help to plan and allocate the water resources to improve the water allocation strategies and in turn water use efficiency and can make inter-canal comparisons. The delineated block boundaries can be refined exactly using the drainage, topography and existing canal network in GIS platform.
