优化井身结构合理选择套管降低钻井成本

钻井成本居高不下已经严重制约了石油工业的发展。华北油田采取低成本战略,在钻井设计施工中,从改变井身结构和套管管串结构入手,探讨降低钻井成本的方法,在上半年完成的106口井中每米钻井成本下降104.34元,共节约成本近3000万元,取得了较好的经济效益。     

建筑工程点线面质量控制

本根据系统论、控制论的基本观点，提出了点线面质量控制法，并就该方法的有关内容加以论述。     

VFP表单任意列表格及嵌入控件的设计

本文针对ＶＦＰ系统在表单中设置表格对象，首先需要确定列数的限制，提出了一个利用宏替换命令和其它事件代码设置任意列表格及嵌入控件的表单程序设计方法。     

On analog circuit design methodology via multi-objective geometric programming

This paper concerns a design methodology for analog circuit problems, which is based on formulating the problem as a multi-objective geometric program （GP）. Multiple objectives are combined into a scalar objective thru certain convex functions and thus can be solved using regular GP algorithms. In contrast to single-objective optimization, simultaneous consideration of all objectives yields a compromising solution among objectives. By varying individual objective＇s weight factor, a Pareto （or trade-off） curve can be constructed, providing designers with a useful decision-making information.     

磁性测量的冲击法及计算程序

主要介绍了磁性测量冲击法的基本原理，并用Fortran语言编写了相应的磁性数据的处理程序，实践证明，该程序实用性强，数据处理既快又精确，效果很好。     

PC-1500计算机在公路测量绘图中的应用

介绍了PC - 15 0 0计算机在公路测量绘图中的应用 ,阐述了施工测量中纵横断面图绘制程序的编制过程 ,并收到了良好的效果。     

网上黑客工具——木马探讨（续一）

5木马的危害 木马的危害主要表现在远程控制方面。木马连接建立后，控制端端口和木马端口之间将会出现一条通道。     

Transforming generate-and-test programs to execute under committed-choice AND-parallelism

This paper concerns the exploitation of user transparent inherent parallelism of pure Prolog programs using program transformation. We describe a novel paradigmenumerate-and-filter for transforming generate-and-test programs for execution under the committed-choice model extended to incorporate multiple solutions based on set enumeration. The paradigm simulates OR-parallelism by stream AND-parallelism integrating OR-parallelism, AND-parallelism, and stream parallelism. Generate-and-test programs are classified into three categories:simple generate-and-test, recursively embedded generate-and-test, and deeply intertwined generate-and-test. The intermediate programs are further transformed to reduce structure copying and metacalls. Algorithms are presented and demonstrated by transforming the representative examples of different classes of generate-and-test programs to Flat Concurrent Prolog equivalents. Statistics show that the techniques are efficient.Funded in part by Cleveland Advanced Manufacturing Program through the State of Ohio as a part of its core research program grant to Center of Automation and Intelligent Systems Research, Case Western Reserve University and NSF equipment grant CDA-8820390 to Kent State University.     

Program verification,defeasible reasoning,and two views of computer science

In this paper I attempt to cast the current program verification debate within a more general perspective on the methodologies and goals of computer science. I show, first, how any method involved in demonstrating the correctness of a physically executing computer program, whether by testing or formal verification, involves reasoning that is defeasible in nature. Then, through a delineation of the senses in which programs can be run as tests, I show that the activities of testing and formal verification do not necessarily share the same goals and thus do not always constitute alternatives. The testing of a program is not always intended to demonstrate a program's correctness. Testing may seek to accept or reject nonprograms including algorithms, specifications, and hypotheses regarding phenomena. The relationship between these kinds of testing and formal verification is couched in a more fundamental relationship between two views of computer science, one properly containing the other.     

Transformations for optimizing interprocess communication and synchronization mechanisms

This paper presents source-level transformations that improve the performance of programs using synchronous and asynchronous message passing primitives, including remote call to an active process (rendezvous). It also discusses the applicability of these transformations to shared memory and distributed environments. The transformations presented reduce the need for context switching, simplify the specific form of communication, and/or reduce the complexity of the given form of communication. One additional transformation actually increases the number of processes as well as the number of context switches to improve program performance. These transformations are shown to be generalizable. Results of hand-applying the transformations to SR programs indicate reductions in execution time exceeding 90% in many cases. The transformations also apply to many commonly occurring synchronization patterns and to other concurrent programming languages such as Ada and Concurrent C. The long term goal of this effort is to include such transformations as an otpimization step, performed automatically by a compiler.This work was supported by NSF under Grant Number CCR88-10617.