A distributed collaborative product design environment based on semantic norm model and role-based access control

With the boom of Internet Technology, it becomes possible to combine designers from different disciplines into one team to support product design globally. In this paper, a distributed collaborative product design environment is presented to support top-down process oriented product design. In conceptual design stage, the artifact is managed by semantic norm model (SNM). In SNM, the designers can define virtual components at early design stage and instantiate those components at later detailed design stage. By role-based access control (RBAC), different roles with corresponding permissions could be assigned to distributed designers, and the designers could concurrently modify different components of the product relevant to his or her roles. Based on the SNM and RBAC system, a distributed collaborative product design environment is developed and the top-down oriented product design process is demonstrated.     

绒线漂染综合控制系统研究应用

介绍了一种集中管理,分散控制的计算机温度自动控制系统,该系统控制精度高,控制方法先进,测量手段简单实用,抗下扰能力强,性能价格比好。在天水宏大绒线厂的试运行中取得了良好的绒线染色效果,并取得了显著的经济效益。     

在多元连接数据查询中最小生成树法的改进应用

本文对最小生成树法在分布式数据库多元连接中的应用进行了阐述和分析,并利用分布式数据库数据的分布性对最小生成树法进行了改进。提出了基于最小生成树法的连接图划分方法将连接图划分成多个子连接图,提高连接操作的并行性,从而使得响应时间得到减少。     

基于Web的分布式共享信息系统设计

通过对基于主机和客户机/服务器应用程序的分析,结合企业实际情况,采用新的设计技术,提出新的设计思想,重新设计基于Web的企业分布式共享信息系统,该系统可在Inter-net、Intranet上稳定的运行和通信,它的运用能提高企业的工作效率,对同行业信息系统的设计具有参考价值。     

云计算环境下的数据存储问题研究

随着计算机技术的不断向前发展,云计算和云存储作为一种崭新的模式,愈发受到个人和企业的关注。本文在对云计算进行简要介绍的基础上,对云计算环境下的数据存储即云存储体进行了分析和研究,展示了云存储的巨大优势,并就制约云存储进一步发展的若干问题进行了讨论。     

基于直接连接的分布式数据库查询优化实现方法研究

首先对分布式数据库查询执行代价模型进行分析,然后对直接连接中的连接运算的方法、连接关系的传输方法和执行场地等问题进行研究,并计算所有评估方法的执行代价,从中选择出最小执行代价的执行方法,最终确定了执行的场地、连接的方法和传输方法.     

Collaborative assignment using belief-desire-intention agent modeling and negotiation with speedup strategies

In this paper, we propose a distributed agent model that applies belief-desire-intention (BDI) reasoning and negotiation for addressing the linear assignment problem (LAP) collaboratively. In resource allocation, LAP is viewed as seeking a concurrent allocation of one different resource for every task to optimize a linear sum objective function. The proposed model provides a basic agent-based foundation needed for efficient resource allocation in a distributed environment. A distributed agent algorithm that has been developed based on the BDI negotiation model is examined both analytically and experimentally. To improve performance in terms of average negotiation speed and solution quality, two initialization heuristics and two different reasoning control strategies are applied, with the latter yielding different variants of the basic algorithm. Extensive simulations suggest that all the heuristic-algorithm combinations can produce a near optimal solution soon enough in some specific sense. The significance and applicability of the research work are also discussed.     

Application of load balancing based on symmetric balanced incomplete block design to random networks

In a load balancing algorithm [O. Lee, M. Anshel, I. Chung, Design of an efficient load balancing algorithm on distributed networks by employing symmetric balanced incomplete block design, IEE Proceedings - Communications 151 (6) (2004) 535-538] based on the SBIBD (Symmetric Balanced Incomplete Block Design), each node receives global workload information by only two round message exchange with traffic overhead, where v is the number of nodes. It is very efficient and works well only when v=p²+p+1 is used for a prime number p. In this paper, we generated a special incidence structure using the SBIBD and then propose a new load balancing algorithm, which executes well for an arbitrary number of nodes. To accomplish this, we add a number of links to nodes in order for each node to receive more than 80% of the workload information by two round message exchange. For performance of our algorithm, we carried out an experiment for the number of nodes, w, which was up to 5000. Traffic overhead is less than in a round and standard deviation of traffic overhead shows that each node has a mostly well-balanced amount of traffic.     

Controllability of second-order infinite-dimensional systems

In the paper, the approximate controllability of linear abstract second-order infinite-dimensional dynamical systems is considered. It is proved using the frequency-domain method, that approximate controllability of second-order system can be verified by the approximate controllability conditions for the corresponding simplified first-order system. General results are then applied for approximate controllability investigation of a vibratory dynamical system modeling flexible mechanical structure. Some special cases are also considered. Moreover, remarks and comments on the relationships between different concepts of controllability are given. The paper extends earlier results on approximate controllability of second-order abstract dynamical systems.