This paper investigates a wireless system with multi-Unmanned Aerial Vehicles(UAVs)for improving the overall throughput.In contrast to previous studies that optimize the locations of UAVs and channel assignment separa...This paper investigates a wireless system with multi-Unmanned Aerial Vehicles(UAVs)for improving the overall throughput.In contrast to previous studies that optimize the locations of UAVs and channel assignment separately,this paper considers the two issues jointly by exploiting Partially Overlapped Channels(POCs).The optimization problem of maximizing network throughput is formulated as a non-convex and non-linear problem.In order to find a practical solution,the problem is decomposed into two subproblems,which are iteratively optimized.First,the optimal locations of UAVs are determined under a fixed channel assignment scheme by solving the mixed-integer second-order cone problem.Second,an efficient POC allocation scheme is determined via the proposed channel assignment algorithm.Simulation results show that the proposed approach not only significantly improves system throughput and service reliability compared with the cases in which only orthogonal channels and stationary UAVs are considered,but also achieves similar performance using the exhaustive search algorithm with lower time complexity.展开更多
With the rapid development of Ubiquitous computing,context-aware technology as one of the core contents of the former has made a series of research progress and achievements.Context-aware technology can automatically ...With the rapid development of Ubiquitous computing,context-aware technology as one of the core contents of the former has made a series of research progress and achievements.Context-aware technology can automatically provide the corresponding services according to the strategy given by the inference engine through sensing the related context of the environment and tasks.It is because context-aware technology can significantly improve the intelligence of computer interaction,the application of this technology to“Intelligent community”which is a new concept built on the highly developed Internet and sensor networks has become more promising and meaningful.As an important part of the intelligent community,the technology is also of great use for the disabled health service.Based on the research of the theory of context-aware technology and the examples of international development applications,this paper designs an ontology based context-aware system framework named CADHS for disabled health service.The hierarchy based framework uses ontology to standardize and formalize context information and complete context modeling.This framework includes the collection and encapsulation of the original context information and constructs a formal reasoning model.Moreover,the framework provides query and subscription services as the external interface of the system.On the basis of this framework,the DHS-Protosystem(Disabled Health Service Protosystem)is designed and implemented.This paper introduces implementation of query and subscription service module.展开更多
基金Thanks to the National Natural Science Foundation of China under Grant No.61702387 for the support of the research in this paper.
文摘This paper investigates a wireless system with multi-Unmanned Aerial Vehicles(UAVs)for improving the overall throughput.In contrast to previous studies that optimize the locations of UAVs and channel assignment separately,this paper considers the two issues jointly by exploiting Partially Overlapped Channels(POCs).The optimization problem of maximizing network throughput is formulated as a non-convex and non-linear problem.In order to find a practical solution,the problem is decomposed into two subproblems,which are iteratively optimized.First,the optimal locations of UAVs are determined under a fixed channel assignment scheme by solving the mixed-integer second-order cone problem.Second,an efficient POC allocation scheme is determined via the proposed channel assignment algorithm.Simulation results show that the proposed approach not only significantly improves system throughput and service reliability compared with the cases in which only orthogonal channels and stationary UAVs are considered,but also achieves similar performance using the exhaustive search algorithm with lower time complexity.
文摘With the rapid development of Ubiquitous computing,context-aware technology as one of the core contents of the former has made a series of research progress and achievements.Context-aware technology can automatically provide the corresponding services according to the strategy given by the inference engine through sensing the related context of the environment and tasks.It is because context-aware technology can significantly improve the intelligence of computer interaction,the application of this technology to“Intelligent community”which is a new concept built on the highly developed Internet and sensor networks has become more promising and meaningful.As an important part of the intelligent community,the technology is also of great use for the disabled health service.Based on the research of the theory of context-aware technology and the examples of international development applications,this paper designs an ontology based context-aware system framework named CADHS for disabled health service.The hierarchy based framework uses ontology to standardize and formalize context information and complete context modeling.This framework includes the collection and encapsulation of the original context information and constructs a formal reasoning model.Moreover,the framework provides query and subscription services as the external interface of the system.On the basis of this framework,the DHS-Protosystem(Disabled Health Service Protosystem)is designed and implemented.This paper introduces implementation of query and subscription service module.
