网上选课系统中用户管理体系的设计

讨论了开发网上选课系统的有关问题，并就其中的用户管理机制及实现技术作了分析和探索。     

分布式数据库在银行代理业务中的实现模型

就银行代理业务在分布式数据库上的实现进行了研究，借助于J2EE规范中的EJB技术来实现对分布式数据库的操作．并利用数据访问对象模式来封装数据存储的细节，实现EJB组件与数据库的松散耦合；用值对象模式封装相关的业务数据，减少数据库的频繁操作，以提高系统性能．     

Distributed certification application via a trusted dealer

Distributed certification via threshold cryptography is much more secure than other ways to protect certification authority (CA)'s private key, and can tolerate some intrusions. As the original system such as ITTC, etc., is unsafe, inefficient and impracitcal in actual network environment, this paper brings up a new distributed certification scheme, which although it generates key shares concentratively, it updates key shares distributedly, and so, avoids single-point failure like ITTC. It not only enhances robustness with Feldman verification and SSL protocol, but can also change the threshold (t, k) flexibly and robustly, and so, is much more practical. In this work, the authors implement the prototype system of the new scheme and test and analyze its performance. Project supported by the Nature Science Foundation of China (No. 79974031) and Zhejiang Nature Science Foundation (No. 600014)     

UHF机械调谐器调谐电容片形的程序设计

采用传输线理论可以计算机械式UHF调谐器对应不同频率点的调谐电容量。在进行满足直线频率关系的调谐电容片形设计时,应当求出调谐电容量Cr与旋转角θ的显式函数关系。但对于分布参数的电路,这有一定的困难。本文采用数值计算方法完成了具有良好直线频率跟踪特性的调谐电容片形的设计,并由计算机自动绘出了片形。     

Sedimentation of a single particle between two parallel walls

The sedimentation of a single circular particle between two parallel walls was studied by means of direct numerical simulation (DNS) and experiment. The improved implementation of distributed Lagrange multiplier/fictitious domain method used in our DNS is a promising new way for simulation of particulate flows. The settling behaviors of the particle are presented ranging in Reynolds number from 0 to about 700, which showed that our results for low Reynolds numbers agreed well with that reported before. Nevertheless, for higher Reynolds numbers our results were different from theirs. The long-term mean equilibrium positions in our results were all on the centerline, but not at off-center position as reported before. In order to validate our simulation, experiments were also conducted. The results showed that the sedimenting behavior simulated in this paper agreed well with our experiment result.     

基于COM+的分布式应用系统设计与部署

COM+作为一种分布式应用开发技术,已经被广泛使用。如何有效地进行基于COM+的分布式应用系统开发与部署,本文将就此作一个简要的探讨。     

PipeCF： a DHT-based Collaborative Filtering recommendation system

Collaborative Filtering (CF) technique has proved to be one of the most successful techniques in recommendation systems in recent years. However, traditional centralized CF system has suffered from its limited scalability as calculation complexity increases rapidly both in time and space when the record in the user database increases. Peer-to-peer (P2P) network has attracted much attention because of its advantage of scalability as an alternative architecture for CF systems. In this paper, authors propose a decentralized CF algorithm, called PipeCF, based on distributed hash table (DHT) method which is the most popular P2P routing algorithm because of its efficiency, scalability, and robustness. Authors also propose two novel approaches: significance refinement (SR) and unanimous amplification (UA), to improve the scalability and prediction accuracy of DHT-based CF algorithm. The experimental data show that our DHT-based CF system has better prediction accuracy, efficiency and scalability than traditiona     

Optimal distributed resource allocation in a wireless sensor network for control systems

INTRODUCTION With the rapid development of wireless com-munication technology, the combination of wireless communication and control systems becomes a new trend of networked control systems. Among the kinds of wireless technologies, wireless sensor network (WSN) has attracted a lot of interest and visibility due to its huge application space. WSN is a kind of wire-less ad-hoc network which connects embedded sen-sors, actuators, and processors and in which each node consists of a wireles…     

面向对象并行程序设计技术

本通过分析面向对象的特点和并行程序设计的要求，提出了“面向对象技术是获得高效率多计算机并行程序设计的有效途径”的观点。同时，介绍了三种面向对象并行程序设计的最新技术。