We study a novel replication mechanism to ensure service continuity against multiple simultaneous server failures.In this mechanism,each item represents a computing task and is replicated intoξ+1 servers for some int...We study a novel replication mechanism to ensure service continuity against multiple simultaneous server failures.In this mechanism,each item represents a computing task and is replicated intoξ+1 servers for some integerξ≥1,with workloads specified by the amount of required resources.If one or more servers fail,the affected workloads can be redirected to other servers that host replicas associated with the same item,such that the service is not interrupted by the failure of up toξservers.This requires that any feasible assignment algorithm must reserve some capacity in each server to accommodate the workload redirected from potential failed servers without overloading,and determining the optimal method for reserving capacity becomes a key issue.Unlike existing algorithms that assume that no two servers share replicas of more than one item,we first formulate capacity reservation for a general arbitrary scenario.Due to the combinatorial nature of this problem,finding the optimal solution is difficult.To this end,we propose a Generalized and Simple Calculating Reserved Capacity(GSCRC)algorithm,with a time complexity only related to the number of items packed in the server.In conjunction with GSCRC,we propose a robust replica packing algorithm with capacity optimization(RobustPack),which aims to minimize the number of servers hosting replicas and tolerate multiple server failures.Through theoretical analysis and experimental evaluations,we show that the RobustPack algorithm can achieve better performance.展开更多
The Internet of Things(IoT)and allied applications have made real-time responsiveness for massive devices over the Internet essential.Cloud-edge/fog ensembles handle such applications'computations.For Beyond 5 th ...The Internet of Things(IoT)and allied applications have made real-time responsiveness for massive devices over the Internet essential.Cloud-edge/fog ensembles handle such applications'computations.For Beyond 5 th Generation(B5G)communication paradigms,Edge Servers(ESs)must be placed within Information Communication Technology infrastructures to meet Quality of Service requirements like response time and resource utilisation.Due to the large number of Base Stations(BSs)and ESs and the possibility of significant variations in placing the ESs within the IoTs geographical expanse for optimising multiple objectives,the Edge Server Placement Problem(ESPP)is NP-hard.Thus,stochastic evolutionary metaheuristics are natural.This work addresses the ESPP using a Particle Swarm Optimization that initialises particles as BS positions within the geography to maintain the workload while scanning through all feasible sets of BSs as an encoded sequence.The Workload-Threshold Aware Sequence Encoding(WTASE)Scheme for ESPP provides the number of ESs to be deployed,similar to existing methodologies and exact locations for their placements without the overhead of maintaining a prohibitively large distance matrix.Simulation tests using open-source datasets show that the suggested technique improves ESs utilisation rate,workload balance,and average energy consumption by 36%,17%,and 32%,respectively,compared to prior works.展开更多
在设计海洋环境信息产品的内容、表现方式、发布流程的基础上,应用ArcGIS Server平台和ArcGIS API for Flex客户端开发技术,建立了海洋环境信息服务系统(MEISS),实现信息产品的发布、审核和可视化展示等功能。该系统可查询展示我国管辖...在设计海洋环境信息产品的内容、表现方式、发布流程的基础上,应用ArcGIS Server平台和ArcGIS API for Flex客户端开发技术,建立了海洋环境信息服务系统(MEISS),实现信息产品的发布、审核和可视化展示等功能。该系统可查询展示我国管辖海域的自然地理、水文动力、环境质量、敏感目标、区域保护与开发利用现状、海洋环境监测评价等信息,为海洋环境保护、海洋科学研究和海洋权益维护提供信息服务和决策支持。展开更多
本文在AJAX理念的指导下,针对WebGIS的不足之处,设计与实现了城市交通矢量WebGIS原型系统。原型系统以ArcGIS Server WebADF框架为核心构建地图引擎,以AJAX开源引擎ExtJS作为前端辅助工具实现查询以及统计分析功能。试验表明,基于AJAX...本文在AJAX理念的指导下,针对WebGIS的不足之处,设计与实现了城市交通矢量WebGIS原型系统。原型系统以ArcGIS Server WebADF框架为核心构建地图引擎,以AJAX开源引擎ExtJS作为前端辅助工具实现查询以及统计分析功能。试验表明,基于AJAX的富客户端WebGIS架构减轻了服务器端的负载,提升了客户端的运行效率,更加高效地提供了Web地理信息服务。展开更多
ArcGIS Server可以构建Web应用、Web服务,ArcGIS Server的出现为网络地图服务提供了一个全新的途径。以ArcGIS Server10.0为平台研究网络地图服务系统的设计与实现,基于B/S三层混合模式,采用ArcGIS REST API和ArcGIS API For Flex,将Arc...ArcGIS Server可以构建Web应用、Web服务,ArcGIS Server的出现为网络地图服务提供了一个全新的途径。以ArcGIS Server10.0为平台研究网络地图服务系统的设计与实现,基于B/S三层混合模式,采用ArcGIS REST API和ArcGIS API For Flex,将ArcSDE作为空间数据引擎,SQLServer作为数据库进行空间数据管理,设计和实现一个具有基本地图操作功能、地图定位、查询、空间分析的地图网络发布系统,为地图的网络服务奠定基础。展开更多
基金supported in part by the National Key R&D Program of China under No.2023YFB2703800the National Science Foundation of China under Grants U22B2027,62172297,62102262,61902276 and 62272311+3 种基金Tianjin Intelligent Manufacturing Special Fund Project under Grants 20211097the China Guangxi Science and Technology Plan Project(Guangxi Science and Technology Base and Talent Special Project)under Grant AD23026096(Application Number 2022AC20001)Henan Provincial Natural Science Foundation of China under Grant 622RC616CCF-Nsfocus Kunpeng Fund Project under Grants CCF-NSFOCUS202207。
文摘We study a novel replication mechanism to ensure service continuity against multiple simultaneous server failures.In this mechanism,each item represents a computing task and is replicated intoξ+1 servers for some integerξ≥1,with workloads specified by the amount of required resources.If one or more servers fail,the affected workloads can be redirected to other servers that host replicas associated with the same item,such that the service is not interrupted by the failure of up toξservers.This requires that any feasible assignment algorithm must reserve some capacity in each server to accommodate the workload redirected from potential failed servers without overloading,and determining the optimal method for reserving capacity becomes a key issue.Unlike existing algorithms that assume that no two servers share replicas of more than one item,we first formulate capacity reservation for a general arbitrary scenario.Due to the combinatorial nature of this problem,finding the optimal solution is difficult.To this end,we propose a Generalized and Simple Calculating Reserved Capacity(GSCRC)algorithm,with a time complexity only related to the number of items packed in the server.In conjunction with GSCRC,we propose a robust replica packing algorithm with capacity optimization(RobustPack),which aims to minimize the number of servers hosting replicas and tolerate multiple server failures.Through theoretical analysis and experimental evaluations,we show that the RobustPack algorithm can achieve better performance.
基金the Deanship of Research and Graduate Studies at King Khalid University for funding this work through the Large Research Project under grant number RGP2/603/46。
文摘The Internet of Things(IoT)and allied applications have made real-time responsiveness for massive devices over the Internet essential.Cloud-edge/fog ensembles handle such applications'computations.For Beyond 5 th Generation(B5G)communication paradigms,Edge Servers(ESs)must be placed within Information Communication Technology infrastructures to meet Quality of Service requirements like response time and resource utilisation.Due to the large number of Base Stations(BSs)and ESs and the possibility of significant variations in placing the ESs within the IoTs geographical expanse for optimising multiple objectives,the Edge Server Placement Problem(ESPP)is NP-hard.Thus,stochastic evolutionary metaheuristics are natural.This work addresses the ESPP using a Particle Swarm Optimization that initialises particles as BS positions within the geography to maintain the workload while scanning through all feasible sets of BSs as an encoded sequence.The Workload-Threshold Aware Sequence Encoding(WTASE)Scheme for ESPP provides the number of ESs to be deployed,similar to existing methodologies and exact locations for their placements without the overhead of maintaining a prohibitively large distance matrix.Simulation tests using open-source datasets show that the suggested technique improves ESs utilisation rate,workload balance,and average energy consumption by 36%,17%,and 32%,respectively,compared to prior works.
文摘在设计海洋环境信息产品的内容、表现方式、发布流程的基础上,应用ArcGIS Server平台和ArcGIS API for Flex客户端开发技术,建立了海洋环境信息服务系统(MEISS),实现信息产品的发布、审核和可视化展示等功能。该系统可查询展示我国管辖海域的自然地理、水文动力、环境质量、敏感目标、区域保护与开发利用现状、海洋环境监测评价等信息,为海洋环境保护、海洋科学研究和海洋权益维护提供信息服务和决策支持。
文摘本文在AJAX理念的指导下,针对WebGIS的不足之处,设计与实现了城市交通矢量WebGIS原型系统。原型系统以ArcGIS Server WebADF框架为核心构建地图引擎,以AJAX开源引擎ExtJS作为前端辅助工具实现查询以及统计分析功能。试验表明,基于AJAX的富客户端WebGIS架构减轻了服务器端的负载,提升了客户端的运行效率,更加高效地提供了Web地理信息服务。
文摘ArcGIS Server可以构建Web应用、Web服务,ArcGIS Server的出现为网络地图服务提供了一个全新的途径。以ArcGIS Server10.0为平台研究网络地图服务系统的设计与实现,基于B/S三层混合模式,采用ArcGIS REST API和ArcGIS API For Flex,将ArcSDE作为空间数据引擎,SQLServer作为数据库进行空间数据管理,设计和实现一个具有基本地图操作功能、地图定位、查询、空间分析的地图网络发布系统,为地图的网络服务奠定基础。
