基于ASP的在线考试系统的设计及应用

一个完整的在线考试系统应该包括考试用户注册系统、在线考试系统、分级账户及试卷管理系统、用户成绩查询系统、帮助系统等。本文提出了一种基于Asp的在线考试系统解决方案,具有移植性好、易于实现等优点。     

舰载直升机仪表设备故障状态Delphi数据库管理系统

一个面向舰载直升机仪表设备故障状态的Delphi数据库管理系统，根据舰载直升机仪表设备的故障特点，运用现代管理理论，利用计算机对舰载直升机仪表设备故障进行状态管理，分别概述了系统的设计原则、系统功能、数据库的结构及数据库建立方法．     

卫星侦察通信环境仿真技术研究

在分析卫星侦察通信环境的基础上，开发了卫星侦察通信环境仿真系统，给出了环境仿真软件流程，并分析了软件实现的关键技术。该系统能够模拟卫星侦察完全截获状态下的常规通信环境，为卫星侦察通信信号的研究提供了环境平台。     

Development of a finite element modeling system for ship structures

In ship structural design, many structural analyses by the finite element method are carried out on models at several different scale levels; for example, a whole ship, cargo hold parts, and detailed structures. However, one serious problem with this design and analysis process is that the generation of the finite element models for a complex configuration is very difficult and laborious. To overcome this problem, an object oriented, finite element modeling system, MODIFY, has been developed by the authors. In this paper, the concept of the finite element modeling system and the techniques for the construction of the system are explained. First, the object oriented data structure of the system, based on the Part-Object concept, is proposed. In this concept, not only the geometry of the domain but also the analytical conditions, such as boundary conditions and material properties, and the finite element model, are represented by the object oriented data structure. By using this data structure, effective finite element model generation can be expected. Second, a mesh generation algorithm based on the frontal method is described. The original frontal method by S.H. Lo was improved for application to three-dimensional curved surfaces. A new inner node placement technique to make quadrilateral elements around stress concentrated areas is also proposed. These techniques are suitable for ship structures, and more accurate results from the finite element analysis can be expected. Moreover, the parallel mesh generation is implemented in MODIFY by using the client-server concept to accelerate mesh generation. Third, a prototype system for the automatic finite element model generation for different analysis levels is proposed. The system is based on the concept of the PD part, which is the part in the design and production stage, and automatic computing of the intersection between PD parts. The validity of this system is demonstrated by some examples.     

基于XML的WEB数据挖掘技术的研究

面向WEB的数据挖掘是当今数据挖掘技术的热点。介绍基于WEB挖掘的难点，阐述XML语言的卓越性以及在WEB挖掘中的重要应用。     

监控器质量分析和检测人员标准化作业评分系统

“监控器质量分析和检测人员标准化作业评分系统”是为了更好更准确地检查出监控装置存在的故障隐患和较好地规范检测人员的行为。文章介绍了该系统的主要功能、设计思路和结构数据流程,运用证明系统提高了监控装置出库的完好率,确保机车安全正点。     

数据库在机车轴承管理中的应用

介绍了机车轴承微机管理系统,本系统利用FOXBASE数据库,对机车各类轴承的出入段情况以及检修数据进行存储、分析,实现了轴承的状态跟踪和科学管理,保障机车的运行安全     

Validation of the 3D biogeochemical model MIRO&CO with field nutrient and phytoplankton data and MERIS-derived surface chlorophyll a images

This paper presents results obtained with MIRO&CO-3D, a biogeochemical model dedicated to the study of eutrophication and applied to the Channel and Southern Bight of the North Sea (48.5°N–52.5°N). The model results from coupling of the COHERENS-3D hydrodynamic model and the biogeochemical model MIRO, which was previously calibrated in a multi-box implementation. MIRO&CO-3D is run to simulate the annual cycle of inorganic and organic carbon and nutrients (nitrogen, phosphorus and silica), phytoplankton (diatoms, nanoflagellates and Phaeocystis), bacteria and zooplankton (microzooplankton and copepods) with realistic forcing (meteorological conditions and river loads) for the period 1991–2003. Model validation is first shown by comparing time series of model concentrations of nutrients, chlorophyll a, diatom and Phaeocystis with in situ data from station 330 (51°26.00′N, 2°48.50′E) located in the centre of the Belgian coastal zone. This comparison shows the model's ability to represent the seasonal dynamics of nutrients and phytoplankton in Belgian waters. However the model fails to simulate correctly the dissolved silica cycle, especially during the beginning of spring, due to the late onset (in the model) of the early spring diatom bloom. As a general trend the chlorophyll a spring maximum is underestimated in simulations. A comparison between the seasonal average of surface winter nutrients and spring chlorophyll a concentrations simulated with in situ data for different stations is used to assess the accuracy of the simulated spatial distribution. At a seasonal scale, the spatial distribution of surface winter nutrients is in general well reproduced by the model with nevertheless a small overestimation for a few stations close to the Rhine/Meuse mouth and a tendency to underestimation in the coastal zone from Belgium to France. PO₄ was simulated best; silica was simulated with less success. Spring chlorophyll a concentration is in general underestimated by the model. The accuracy of the simulated phytoplankton spatial distribution is further evaluated by comparing simulated surface chlorophyll a with that derived from the satellite sensor MERIS for the year 2003. Reasonable agreement is found between simulated and satellite-derived regions of high chlorophyll a with nevertheless discrepancies close to the boundaries.     

连接池技术在电子商务中的应用研究

电子商务的应用对数据访问要求越来越高,连接池技术很好地解决了因数据库频繁访问造成的系统性能下降的问题。本文主要从连接池的原理、机制、管理等几个方面阐明其技术在电子商务中的应用。     

An experimental testbed for mobile offshore base control concepts

 The concept of a mobile offshore base (MOB) reflects the need to stage and support military and humanitarian operations anywhere in the world. A MOB is a self-propelled, modular, floating platform that can be assembled into lengths of up to 2 km, as required, to provide logistic support to US military operations where fixed bases are not available or adequate. It accommodates the take-off and landing of C17 aircraft, and can be used for storage, as well as to send resources quickly to shore. In most concepts, the structure is made of three to five modules, which have to perform long-term station-keeping in the presence of winds, waves, and currents. This is usually referred to as dynamic positioning (DP). In the MOB, the alignment is maintained through the use of thrusters, connectors, or a combination of both. In this paper, we consider the real-time control of scaled models of a MOB. The modules are built at the 1 : 150 scale, and are kept aligned by rotating thrusters under a hierarchical hybrid control scheme. This paper describes a physical testbed developed at the University of California, Berkeley, under a grant from the US Office of Naval Research, for the purpose of evaluating competing MOB control concepts. Received: June 4, 2002 / Accepted: October 30, 2002 Acknowledgments. This material is based on work supported by the MOB Program of the US Office of Naval Research under grant N00014-98-1-0744. The authors would like to thank the Link Foundation for its support. Many thanks go to Stephen Spry for his experimental work. The photographs are courtesy of Bill Stone, Gerald Stone, and Jay Sullivan of the PATH Publications staff. Address correspondence to: A.R. Girard (e-mail: anouck@eecs.berkeley.edu)