分析当前信息系统存在的主要问题,介绍信息交换平台是一个基于点对点(Peer to Peer)的信息发布系统。在这个系统里,从信息的产生、采集、加工、存储、发布、消费到监管,形成了一个完整的信息生命体系。基于XML技术,经过对信息交换平台...分析当前信息系统存在的主要问题,介绍信息交换平台是一个基于点对点(Peer to Peer)的信息发布系统。在这个系统里,从信息的产生、采集、加工、存储、发布、消费到监管,形成了一个完整的信息生命体系。基于XML技术,经过对信息交换平台的信息描述深入的研究,提出了开放信息模型(OIM),对信息进行统一的描述,使信息可以跨平台发布。OIM研究目标有两个:一个是信息模型的设计;另一个是信息模型在信息交换平台里的实现。本文重点设计了针对网络环境的用户授权管理模型、角色访问控制模型、工作流模型等,提供对应用系统的安全服务,从而避免应用系统和授权系统紧耦合,同时保证实现应用系统语言实现的无关性。提供了用户授权管理系统的运行界面,给出测试实例,比较了测试数据。实践证明,该研究使开放信息系统共享授权服务,加快开发速度,减少开发成本,使应用系统开发更易维护;另一方面,通过安全管理平台从全局的角度来保证系统完整性和一致性,减少敏感信息泄漏的机会。展开更多
By inducing the typical inventory control problem - the bullwhip effect, this paper presents vendor managed inventory (VMI) control methods on the basis of traditional methods of inventory management methods, construc...By inducing the typical inventory control problem - the bullwhip effect, this paper presents vendor managed inventory (VMI) control methods on the basis of traditional methods of inventory management methods, constructs a VMI mathematics model, and analyzes the influence of VMI on inventory cost and channel profit. Finally, a special case is studied to verify that VMI is an effective supply chain strategy that can not only increase channel profit of supplier and customer but also improve full channel coordination, thereby reducing the bullwhip effect.展开更多
This paper presents a description and analysis of the most important models to predict each of the Road User Costs components （Vehicle Operating Costs, Accident Costs and Value of Time） and proposes a model for esti...This paper presents a description and analysis of the most important models to predict each of the Road User Costs components （Vehicle Operating Costs, Accident Costs and Value of Time） and proposes a model for estimating RUC components suitable for the Portuguese road network. These results are part of a research which aimed to obtain a Road User Cost Model to be used as a tool in road management systems. This model is different from other models by the fact that it includes a simple formulation that allows calibration and calculation of cost parameters, for any year, in a simple and fast way, providing trustworthy results. The required data is already available in Portuguese institutions, allowing periodic revision of cost parameters to insure accuracy.展开更多
After analysis of the existing problems of traditional RBAC model, user group and resource domain are introduced to conduct finely granular extension of RBAC model. Extended model reduces the redundancy of roles, lowe...After analysis of the existing problems of traditional RBAC model, user group and resource domain are introduced to conduct finely granular extension of RBAC model. Extended model reduces the redundancy of roles, lowers the complexity of authorization management and enhances the flexibility and maintainability of users＇ authorization. It is well proved in its application in postgraduate student management system.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No.603773040(国家自然科学基金)the National High-Tech Research and Development Plan of China under Grant Nos.863-317-01-04-992003AA142150(国家高技术研究发展计划(863))
文摘分析当前信息系统存在的主要问题,介绍信息交换平台是一个基于点对点(Peer to Peer)的信息发布系统。在这个系统里,从信息的产生、采集、加工、存储、发布、消费到监管,形成了一个完整的信息生命体系。基于XML技术,经过对信息交换平台的信息描述深入的研究,提出了开放信息模型(OIM),对信息进行统一的描述,使信息可以跨平台发布。OIM研究目标有两个:一个是信息模型的设计;另一个是信息模型在信息交换平台里的实现。本文重点设计了针对网络环境的用户授权管理模型、角色访问控制模型、工作流模型等,提供对应用系统的安全服务,从而避免应用系统和授权系统紧耦合,同时保证实现应用系统语言实现的无关性。提供了用户授权管理系统的运行界面,给出测试实例,比较了测试数据。实践证明,该研究使开放信息系统共享授权服务,加快开发速度,减少开发成本,使应用系统开发更易维护;另一方面,通过安全管理平台从全局的角度来保证系统完整性和一致性,减少敏感信息泄漏的机会。
文摘By inducing the typical inventory control problem - the bullwhip effect, this paper presents vendor managed inventory (VMI) control methods on the basis of traditional methods of inventory management methods, constructs a VMI mathematics model, and analyzes the influence of VMI on inventory cost and channel profit. Finally, a special case is studied to verify that VMI is an effective supply chain strategy that can not only increase channel profit of supplier and customer but also improve full channel coordination, thereby reducing the bullwhip effect.
文摘This paper presents a description and analysis of the most important models to predict each of the Road User Costs components （Vehicle Operating Costs, Accident Costs and Value of Time） and proposes a model for estimating RUC components suitable for the Portuguese road network. These results are part of a research which aimed to obtain a Road User Cost Model to be used as a tool in road management systems. This model is different from other models by the fact that it includes a simple formulation that allows calibration and calculation of cost parameters, for any year, in a simple and fast way, providing trustworthy results. The required data is already available in Portuguese institutions, allowing periodic revision of cost parameters to insure accuracy.
文摘After analysis of the existing problems of traditional RBAC model, user group and resource domain are introduced to conduct finely granular extension of RBAC model. Extended model reduces the redundancy of roles, lowers the complexity of authorization management and enhances the flexibility and maintainability of users＇ authorization. It is well proved in its application in postgraduate student management system.
