An Inverse Transmission Scattering Problem and the Enclosure Method

We consider an inverse scattering problem in two-dimensions for a penetrable polygonal obstacle having different density from the back ground medium, however, the speed of sound is constant in the whole space. Using a single set of the Cauchy data of the response for a single incident plane wave with a fixed wave number on a circle surrounding the obstacle, we give an extraction formula of the convex hull of the obstacle. An algorithm based on the formula is also described.     

冷藏车层叠式蒸发器应用R404A与R22和R134a的比较

采用分布参数法对层叠式蒸发器建立数学模型，并对蒸发器采用R404A，R22和R134a时的换热和流动性能进行模拟比较。结果表明，在空调工况范围内，新型中低温混合制冷剂R404A具有R134a换热性能好和R22压降小的特点，能够很好地适用于冷藏车系统空调侧层叠式蒸发器。     

R417A替代家用空调器用R22的实验研究

简要介绍R22的替代选择及R417A性质。在焓差试验台上对分体式房间空调器分别用R22及R417A进行各种工况下的性能实验，分析实验结果并指出用R417A替代R22的可能性。     

在.Net平台下建立田野考古数字化平台

田野考古是考古学的重要分支，田野考古数字化平台是一套专门应用于田野考古工作的基于Web的应用系统。文中阐述了一个基于Microsoft．Net架构下的三层结构的田野考古应用系统的设计与实现。重点讨论了在涉及数据复杂的情况下，如何通过O／R Mapping提高开发效率的问题。提出并实现了一套自定义的基于描述的O／R Mapping方案。     

一种双向动态口令认证系统的研究

在研究现有身份认证系统中存在的安全问题的基础上，提出了一种双向动态口令认证方案，给出了方案的实现过程，并对方案进行了安全性分析。本方案的特点是：提供了服务器和客户的双向认证，能够抵御假冒攻击；双向认证的实现不需要依赖于第三方认证中心来实现；认证信息保持动态性，能有效防止重放攻击。     

项目总控支持系统中集成工作分解结构建模及其实现

针对大型工程项目集成化管理的需求,提出了一类集成工作分解结构,将大型工程项目中多个管理目标子系统融入到一个统一的框架中,为项目总控支持系统的实现提供底层的支持.在结合考虑实际工程背景给出该结构的E-R模型之后,又详细叙述了该模型在关系数据库中的实现方法和其中的重要环节.考虑到与传统的工作分解结构编码的兼容性,还简述了从模型中按管理目标得到多套WBS编码的流程方法.     

论资本市场的分形结构:以青岛市为例

在对有效市场假说分析的基础上 ,指出了传统资本理论分析的不足。以青岛市目前上市交易的6家公司股票日收盘价为例 ,用分形理论对我国股票市场的分形结构与分形维进行研究。结果表明 ,我国股票市场具有明显的分形结构 ,各股价格变化可由 3～ 4个状态变量来描述     

巧用FIX DMACS软件解决异种机型间的通讯

介绍了莱钢烧结厂生产调度指挥系统如何实现对1#烧结机Honeywell R1500优化控制系统和Modicon984系列PLC控制系统的数据通讯，解决了不同控制系统之间因网络协议不同而造成的通讯困难。     

Numerical solution of the Boltzmann equation on the uniform grid

In the present paper a new numerical method for the Boltzmann equation is developed. The gain part of the collision integral is written in a form which allows its numerical computation on the uniform grid to be carried out efficiently. The amount of numerical work is shown to be of the order O(n ⁶log(n)) for the most general model of interaction and of the order O(n ⁶) for the Variable Hard Spheres (VHS) interaction model, while the formal accuracy is of the order O(n ⁻²). Here n denotes the number of discretisation points in one direction of the velocity space. Some numerical examples for Maxwell pseudo-molecules and for the hard spheres model illustrate the accuracy and the efficiency of the method in comparison with DSMC computations in the spatially homogeneous case. Received June 18, 2002; revised August 23, 2002 Published online: October 24, 2002     

The completeness and applications of the formal system B

Since the formal deductive system (?) was built up in 1997, it has played important roles in the theoretical and applied research of fuzzy logic and fuzzy reasoning. But, up to now, the completeness problem of the system (?) is still an open problem. In this paper, the properties and structure of R0 algebras are further studied, and it is shown that every tautology on the R0 interval [0,1] is also a tautology on any R0 algebra. Furthermore, based on the particular structure of (?) -Lindenbaum algebra, the completeness and strong completeness of the system (?) are proved. Some applications of the system (?) in fuzzy reasoning are also discussed, and the obtained results and examples show that the system (?) is suprior to some other important fuzzy logic systems.