多量程数据采集记录装置的设计

通常的数据采集与记录装置不易实现多量程测量。通过对标度方程进行分析得知,要改变量程只须改变两个参数——标度因子和量程下限。我们设计了一个使用单片机的多量程数据采集和记录装置,能处理多达256种量程。本文叙述了算法分析、硬件和软件的设计以及该装置的性能指标。     

Delay-insensitive codes — an overview

The problem of delay-insensitive data communication is described. The notion of delay-insensitive code is defined, giving precise conditions under which delay-insensitive data communication is feasible. Examples of these codes are presented and analyzed. It appears that delay-insensitive codes are equivalent with antichains in partially ordered sets and with all unidirectional error-detecting codes. Tom Verhoeff received the B.S. and M.S. degrees in mathematics from Eindhoven University of Technology, The Netherlands, in 1985. He is currently an Assistant Professor at the Department of Mathematics and Computing Science of the same university. His main research interests are parallel computations, especially formalisms for their specification and design, and their implementation as delay-insensitive VLSI circuits.     

凤滩水电厂自动发电控制策略

介绍了凤滩水电厂自动发电控制(AGC)策略的实现方法,重点介绍了修正等容量比例有功分配方法及相应措施.程序设计的原则是,机组紧跟目标负荷的情况下,在最佳效率下运行,同时减少机组开/停机次数、有功调节频率和跨越振动区次数,从而减少机组磨损,兼顾运行效率和机组运行安全.     

用常规电阻率测井资料确定水淹层的剩余油饱和度

油田综合含水越来越高，利用电阻率测井资料确定地层的剩余油饱和度变得非常困难。针对这一问题，提出了确定地层水民阻率和含油饱和度的方法。（１）利用已知的地怪水分析资料，采用井下自然电位刻度，井间对经和双自然电位一方法来示准地层水混合电阻率，然后利用相邻井相同地层的电阻率对比方法求含水饱和度。（２）利用电阻率的横向探测特性，避开阿尔奇公式中ｍ、ａ选择上的困难，采用横向法计算水淹层目前的含水饱和度。利用以     

An object-oriented product database using ROSE

A product database for a design and manufacturing enterprise serves as a repository for the data needed to manufacture a product. This paper discusses how an object-oriented persistent object manager named ROSE, under development at Rensselaer, has been used in the Rensselaer CIM program to develop a STEP/PDES-compliant product database for its research test bed. In so doing, it provides an overview of the requirements for a product database system in an integrated design and manufacturing facility, and it discusses how the chosen system meets these requirements.     

Integration of knowledge-based systems with data processing

Transaction Oriented Prolog-Online Environment is a multi-user, mainframe implementation of the logic programming language Prolog, specially designed and developed for the data processing environment. This article describes the background, functionality, implementation and use of TOP-ONE, stressing that applications of knowledge-based systems technology to data processing environments will achieve full success only when existing systems and existing conventional data are incorporated within the applications.     

A process-control and diagnostic tool based on continuous fuzzy Petri nets

The use of Petri nets and fuzzy logic in intelligent process control has caught the attention of many researchers. In this paper, a Continuous Fuzzy Petri Net (CFPN) tool which integrates the three technologies of fuzzy control, Petri nets and real-time expert systems is presented. The CFPN approach can deal with real-time continuous inferencing, for the purpose of process monitoring and diagnostics, at a high level in the presence of uncertainty. This tool has been implemented in the G2 real-time expert-system environment and is currently being used by ESSO Canada.     

Nonparametric estimation from length-biased data under competing risks

A new model for cross-sectional lifetime data is presented. The model is based on the length-bias assumption, and it is adapted to situations in which several types of censoring may occur. The NPMLE of the survival function is derived. An EM-algorithm to approximate the NPMLE is devised. The performance of the introduced estimator is investigated through simulations. A real set of data collected as part of a study on unemployment duration in Spain is used for illustration purposes.     

Developing real-time knowledge-based systems with PERFECT

PERFECT (Programming EnviRonment For Expert systems Constrained in reasoning Time) is aimed at providing the necessary engineering support in real-time knowledge-based system development. PERFECT bridges the gap between the traditional analysis and design methodologies, and the implementation tools for these systems. It does so by providing the means to construct a knowledge model and to choose a suitable inference strategy. Subsequently the properties of the knowledge model and inference strategy may be analysed. For instance, it may be checked whether the knowledge model contains sufficient knowledge to diagnose a fault in an industrial process. Moreover, it may be checked whether the inference engine is able to provide an answer to a certain problem in time. If not, the analyser of PERFECT proposes an alternative structure of the knowledge model. When the constructed knowledge model and the chosen inference strategy show the required time efficiency, the compiler of PERFECT may translate them to an actual real-time knowledge based system in COGSYS. In addition, guidelines are provided with respect to the design of the human-machine interface. The resulting system is an instrument—a source of information that can be used by the human operator during problem-solving, rather than a prosthesis—a device that solves the entire problem by itself and presents the outcome to the human operator.