According to the previous achievement, the task assignment under the constraint of timing continuity for a cooperative air combat is studied. An extensive task assignment scenario with the background of the cooperativ...According to the previous achievement, the task assignment under the constraint of timing continuity for a cooperative air combat is studied. An extensive task assignment scenario with the background of the cooperative air combat is proposed. The utility and time of executing a task as well as the continuous combat ability are defined. The concept of the matching method of weapon and target is modified based on the analysis of the air combat scenario. The constraint framework is also redefined according to a new objective function. The constraints of timing and continuity are formulated with a new method, at the same time, the task assignment and integer programming models of the cooperative combat are established. Finally, the assignment problem is solved using the integrated linear programming software and the simulation shows that it is feasible to apply this modified model in the cooperative air combat for tasks cooperation and it is also efficient to optimize the resource assignment.展开更多
This paper proposes new methods and strategies for Multi-UAVs cooperative attacks with safety and time constraints in a complex environment.Delaunay triangle is designed to construct a map of the complex flight enviro...This paper proposes new methods and strategies for Multi-UAVs cooperative attacks with safety and time constraints in a complex environment.Delaunay triangle is designed to construct a map of the complex flight environment for aerial vehicles.Delaunay-Map,Safe Flight Corridor(SFC),and Relative Safe Flight Corridor(RSFC)are applied to ensure each UAV flight trajectory's safety.By using such techniques,it is possible to avoid the collision with obstacles and collision between UAVs.Bezier-curve is further developed to ensure that multi-UAVs can simultaneously reach the target at the specified time,and the trajectory is within the flight corridor.The trajectory tracking controller is also designed based on model predictive control to track the planned trajectory accurately.The simulation and experiment results are presented to verifying developed strategies of Multi-UAV cooperative attacks.展开更多
In this paper, we investigate the power-minimizing resource allocation problem in multiuser cooperative relay communication systems. A joint optimization problem involving subcarrier assignment, relay selection and po...In this paper, we investigate the power-minimizing resource allocation problem in multiuser cooperative relay communication systems. A joint optimization problem involving subcarrier assignment, relay selection and power allocation is formulated. Since the problem cannot be solved directly, we decompose it into three subproblems. According to the equivalent channel gains and the target rates of users, the subcarrier assignment and relay selection are conducted. Motivated by the water-filling algorithm, we propose a power allocation algorithm with cooperative features. Simulations results indicate that the proposed algorithm performs better in terms of the total transmit power consumption than the existing algorithms.展开更多
The task assignment problem of multiple heterogeneous unmanned aerial vehicles (UAVs), concerned with cooperative decision making and control, is studied in this paper. The heterogeneous vehicles have different oper...The task assignment problem of multiple heterogeneous unmanned aerial vehicles (UAVs), concerned with cooperative decision making and control, is studied in this paper. The heterogeneous vehicles have different operational capabilities and kinematic constraints, and carry limited resources (e.g., weapons) onboard. They are designated to perform multiple consecutive tasks cooperatively on multiple ground targets. The problem becomes much more complicated because of these terms of heterogeneity. In order to tackle the challenge, we modify the former genetic algorithm with multi-type genes to stochastically search a best solution. Genes of chromo- somes are different, and they are assorted into several types according to the tasks that must be performed on targets. Different types of genes are processed specifically in the improved genetic operators including initialization, crossover, and mutation. We also present a mirror representation of vehicles to deal with the limited resource constraint. Feasible chromosomes that vehicles could perform tasks using their limited resources under the assignment are created and evolved by genetic operators. The effect of the proposed algorithm is demonstrated in numerical simulations. The results show that it effectively provides good feasible solutions and finds an optimal one.展开更多
With the rapid development of Unmanned Aerial Vehicle(UAV)technology,one of the emerging fields is to utilize multi-UAV as a team under autonomous control in a complex environment.Among the challenges in fully achievi...With the rapid development of Unmanned Aerial Vehicle(UAV)technology,one of the emerging fields is to utilize multi-UAV as a team under autonomous control in a complex environment.Among the challenges in fully achieving autonomous control,Cooperative task assignment stands out as the key function.In this paper,we analyze the importance and difficulties of multiUAV cooperative task assignment in characterizing scenarios and obtaining high-quality solutions.Furthermore,we present three promising directions for future research:Cooperative task assignment in a dynamic complex environment,in an unmanned-manned aircraft system and in a UAV swarm.Our goal is to provide a brief review of multi-UAV cooperative task assignment for readers to further explore.展开更多
Cooperative communication for wireless networks has gained a lot of recent interest due to its ability to mitigate fading with exploration of spatial diversity. In this paper, we study a joint optimization problem of ...Cooperative communication for wireless networks has gained a lot of recent interest due to its ability to mitigate fading with exploration of spatial diversity. In this paper, we study a joint optimization problem of jointly considering transmission mode selection, relay assignment and power allocation to maximize the capacity of the network through cooperative wireless communications. This problem is much more challenging than relay assignment considered in literature work which simply targets to maximize the transmission capacity for a single transmission pair. We formulate the problem as a variation of the maximum weight matching problem where the weight is a function over power values which must meet power constraints (VMWMC). Although VMWMC is a non-convex problem whose complexity increases exponentially with the number of relay nodes, we show that the duality gap of VMWMC is virtual zero. Based on this result, we propose a solution using Lagrange dual decomposition to reduce the computation complexity. We do simulations to evaluate the performance of the proposed solution. The results show that our solution can achieve maximum network capacity with much less computation time compared with exhaustive search, and our solution outperforms existing sub-optimal solutions that can only achieve much lower network capacity.展开更多
Cooperative communication through energy harvested relays in Cognitive Internet of Things(CIoT)has been envisioned as a promising solution to support massive connectivity of Cognitive Radio(CR)based IoT devices and to...Cooperative communication through energy harvested relays in Cognitive Internet of Things(CIoT)has been envisioned as a promising solution to support massive connectivity of Cognitive Radio(CR)based IoT devices and to achieve maximal energy and spectral efficiency in upcoming wireless systems.In this work,a cooperative CIoT system is contemplated,in which a source acts as a satellite,communicating with multiple CIoT devices over numerous relays.Unmanned Aerial Vehicles(UAVs)are used as relays,which are equipped with onboard Energy Harvesting(EH)facility.We adopted a Power Splitting(PS)method for EH at relays,which are harvested from the Radio frequency(RF)signals.In conjunction with this,the Decode and Forward(DF)relaying strategy is used at UAV relays to transmit the messages from the satellite source to the CIoT devices.We developed a Multi-Objective Optimization(MOO)framework for joint optimization of source power allocation,CIoT device selection,UAV relay assignment,and PS ratio determination.We formulated three objectives:maximizing the sum rate and the number of admitted CIoT in the network and minimizing the carbon dioxide emission.The MOO formulation is a Mixed-Integer Non-Linear Programming(MINLP)problem,which is challenging to solve.To address the joint optimization problem for an epsilon optimal solution,an Outer Approximation Algorithm(OAA)is proposed with reduced complexity.The simulation results show that the proposed OAA is superior in terms of CIoT device selection and network utility maximization when compared to those obtained using the Nonlinear Optimization with Mesh Adaptive Direct-search(NOMAD)algorithm.展开更多
协作频谱感知是认知无线电网络的基础和关键阶段,频谱检测过程中的节点分配策略将直接决定联合频谱感知的结果。介绍了多种分配认知终端的方法,旨在提高频谱感知的效率和公平性。针对不同子频带的感知效率,提出了一种称为由频点占用导...协作频谱感知是认知无线电网络的基础和关键阶段,频谱检测过程中的节点分配策略将直接决定联合频谱感知的结果。介绍了多种分配认知终端的方法,旨在提高频谱感知的效率和公平性。针对不同子频带的感知效率,提出了一种称为由频点占用导致的无效传输参数(inefficient transport parameter,ITP)指标来评估通信性能,给出了感知效率优化问题的闭式表达解,设计的场景包括终端对相同频带有不同的感知性能和相同的感知性能。针对不同子频带间的感知公平性,提出了两种分配算法:弓形分配算法和类划分分配算法。子频带间的公平性通过评估子带中最差的感知性能进行衡量。为了适用于实际场景,加入了频段属性参数来增强公平性,该参数考虑了主用户使用不同频段的优先级及抗干扰能力。仿真结果表明,所提出的策略显著改善了认知无线电网络中的ITP,特别是在子频带利用率不同的情况下,提出的弓形分配算法在公平性不明显降低的情况下,复杂度有明显改善。展开更多
Powerful expressive ability of semantic information, to be easily computed and flexibility are basic features of digital product model (DPM). Using ontology and object-oriented principle (OOP) together to cope with pr...Powerful expressive ability of semantic information, to be easily computed and flexibility are basic features of digital product model (DPM). Using ontology and object-oriented principle (OOP) together to cope with problems in modeling is brought forward in this paper. The two are widely used and do well in modeling, but they each alone cannot cope with all issues and new challenges. Three basic requests are pointed out in DPM modeling. Status, problems, and root of current non-semantic and semantic models are introduced. Ontology, OOP, and their difference are introduced. It is found that the two are entirely complementary with each other. How to assign the roles and to cooperate for the two in coping with the three basic issues in DPM modeling are explained in detail.展开更多
基金supported by the National Natural Science Foundation of China(61472441)
文摘According to the previous achievement, the task assignment under the constraint of timing continuity for a cooperative air combat is studied. An extensive task assignment scenario with the background of the cooperative air combat is proposed. The utility and time of executing a task as well as the continuous combat ability are defined. The concept of the matching method of weapon and target is modified based on the analysis of the air combat scenario. The constraint framework is also redefined according to a new objective function. The constraints of timing and continuity are formulated with a new method, at the same time, the task assignment and integer programming models of the cooperative combat are established. Finally, the assignment problem is solved using the integrated linear programming software and the simulation shows that it is feasible to apply this modified model in the cooperative air combat for tasks cooperation and it is also efficient to optimize the resource assignment.
基金National Natural Science Foundation of China(No.61903350)Beijing Institute of Technology Research Fund Program for Young Scholars。
文摘This paper proposes new methods and strategies for Multi-UAVs cooperative attacks with safety and time constraints in a complex environment.Delaunay triangle is designed to construct a map of the complex flight environment for aerial vehicles.Delaunay-Map,Safe Flight Corridor(SFC),and Relative Safe Flight Corridor(RSFC)are applied to ensure each UAV flight trajectory's safety.By using such techniques,it is possible to avoid the collision with obstacles and collision between UAVs.Bezier-curve is further developed to ensure that multi-UAVs can simultaneously reach the target at the specified time,and the trajectory is within the flight corridor.The trajectory tracking controller is also designed based on model predictive control to track the planned trajectory accurately.The simulation and experiment results are presented to verifying developed strategies of Multi-UAV cooperative attacks.
文摘In this paper, we investigate the power-minimizing resource allocation problem in multiuser cooperative relay communication systems. A joint optimization problem involving subcarrier assignment, relay selection and power allocation is formulated. Since the problem cannot be solved directly, we decompose it into three subproblems. According to the equivalent channel gains and the target rates of users, the subcarrier assignment and relay selection are conducted. Motivated by the water-filling algorithm, we propose a power allocation algorithm with cooperative features. Simulations results indicate that the proposed algorithm performs better in terms of the total transmit power consumption than the existing algorithms.
文摘The task assignment problem of multiple heterogeneous unmanned aerial vehicles (UAVs), concerned with cooperative decision making and control, is studied in this paper. The heterogeneous vehicles have different operational capabilities and kinematic constraints, and carry limited resources (e.g., weapons) onboard. They are designated to perform multiple consecutive tasks cooperatively on multiple ground targets. The problem becomes much more complicated because of these terms of heterogeneity. In order to tackle the challenge, we modify the former genetic algorithm with multi-type genes to stochastically search a best solution. Genes of chromo- somes are different, and they are assorted into several types according to the tasks that must be performed on targets. Different types of genes are processed specifically in the improved genetic operators including initialization, crossover, and mutation. We also present a mirror representation of vehicles to deal with the limited resource constraint. Feasible chromosomes that vehicles could perform tasks using their limited resources under the assignment are created and evolved by genetic operators. The effect of the proposed algorithm is demonstrated in numerical simulations. The results show that it effectively provides good feasible solutions and finds an optimal one.
基金supported in part by the National Natural Science Foundation of China(Nos.61671031,61722102,91738301)。
文摘With the rapid development of Unmanned Aerial Vehicle(UAV)technology,one of the emerging fields is to utilize multi-UAV as a team under autonomous control in a complex environment.Among the challenges in fully achieving autonomous control,Cooperative task assignment stands out as the key function.In this paper,we analyze the importance and difficulties of multiUAV cooperative task assignment in characterizing scenarios and obtaining high-quality solutions.Furthermore,we present three promising directions for future research:Cooperative task assignment in a dynamic complex environment,in an unmanned-manned aircraft system and in a UAV swarm.Our goal is to provide a brief review of multi-UAV cooperative task assignment for readers to further explore.
基金supported by the National Basic Research 973 Program of China under Grant No. 2012CB315801the National Natural Science Foundation of China under Grant Nos. 61133015, 61003305, 61173167the Ph.D. Programs Foundation of Ministry of Education of China under Grant No. 20100161120022
文摘Cooperative communication for wireless networks has gained a lot of recent interest due to its ability to mitigate fading with exploration of spatial diversity. In this paper, we study a joint optimization problem of jointly considering transmission mode selection, relay assignment and power allocation to maximize the capacity of the network through cooperative wireless communications. This problem is much more challenging than relay assignment considered in literature work which simply targets to maximize the transmission capacity for a single transmission pair. We formulate the problem as a variation of the maximum weight matching problem where the weight is a function over power values which must meet power constraints (VMWMC). Although VMWMC is a non-convex problem whose complexity increases exponentially with the number of relay nodes, we show that the duality gap of VMWMC is virtual zero. Based on this result, we propose a solution using Lagrange dual decomposition to reduce the computation complexity. We do simulations to evaluate the performance of the proposed solution. The results show that our solution can achieve maximum network capacity with much less computation time compared with exhaustive search, and our solution outperforms existing sub-optimal solutions that can only achieve much lower network capacity.
文摘Cooperative communication through energy harvested relays in Cognitive Internet of Things(CIoT)has been envisioned as a promising solution to support massive connectivity of Cognitive Radio(CR)based IoT devices and to achieve maximal energy and spectral efficiency in upcoming wireless systems.In this work,a cooperative CIoT system is contemplated,in which a source acts as a satellite,communicating with multiple CIoT devices over numerous relays.Unmanned Aerial Vehicles(UAVs)are used as relays,which are equipped with onboard Energy Harvesting(EH)facility.We adopted a Power Splitting(PS)method for EH at relays,which are harvested from the Radio frequency(RF)signals.In conjunction with this,the Decode and Forward(DF)relaying strategy is used at UAV relays to transmit the messages from the satellite source to the CIoT devices.We developed a Multi-Objective Optimization(MOO)framework for joint optimization of source power allocation,CIoT device selection,UAV relay assignment,and PS ratio determination.We formulated three objectives:maximizing the sum rate and the number of admitted CIoT in the network and minimizing the carbon dioxide emission.The MOO formulation is a Mixed-Integer Non-Linear Programming(MINLP)problem,which is challenging to solve.To address the joint optimization problem for an epsilon optimal solution,an Outer Approximation Algorithm(OAA)is proposed with reduced complexity.The simulation results show that the proposed OAA is superior in terms of CIoT device selection and network utility maximization when compared to those obtained using the Nonlinear Optimization with Mesh Adaptive Direct-search(NOMAD)algorithm.
文摘协作频谱感知是认知无线电网络的基础和关键阶段,频谱检测过程中的节点分配策略将直接决定联合频谱感知的结果。介绍了多种分配认知终端的方法,旨在提高频谱感知的效率和公平性。针对不同子频带的感知效率,提出了一种称为由频点占用导致的无效传输参数(inefficient transport parameter,ITP)指标来评估通信性能,给出了感知效率优化问题的闭式表达解,设计的场景包括终端对相同频带有不同的感知性能和相同的感知性能。针对不同子频带间的感知公平性,提出了两种分配算法:弓形分配算法和类划分分配算法。子频带间的公平性通过评估子带中最差的感知性能进行衡量。为了适用于实际场景,加入了频段属性参数来增强公平性,该参数考虑了主用户使用不同频段的优先级及抗干扰能力。仿真结果表明,所提出的策略显著改善了认知无线电网络中的ITP,特别是在子频带利用率不同的情况下,提出的弓形分配算法在公平性不明显降低的情况下,复杂度有明显改善。
基金Supported by the Ministries’ Basic Research Foundation, China Knowledge Engineering Platform for Enterprise Innovative Design(No. B0920060901)
文摘Powerful expressive ability of semantic information, to be easily computed and flexibility are basic features of digital product model (DPM). Using ontology and object-oriented principle (OOP) together to cope with problems in modeling is brought forward in this paper. The two are widely used and do well in modeling, but they each alone cannot cope with all issues and new challenges. Three basic requests are pointed out in DPM modeling. Status, problems, and root of current non-semantic and semantic models are introduced. Ontology, OOP, and their difference are introduced. It is found that the two are entirely complementary with each other. How to assign the roles and to cooperate for the two in coping with the three basic issues in DPM modeling are explained in detail.