计算机安全漏洞分类研究

计算机及网络安全问题的根源在于计算机漏洞的存在。漏洞是实施网络攻击和加强网络防护的关键因素,漏洞的分类研究是漏洞研究的基础。该文首先给出了计算机安全漏洞的定义并分析了漏洞分类的重要意义,然后介绍了典型的漏洞分类方法和目前常用的漏洞分类法,在此基础上,从多维分类方式和动态变化方式上提出了漏洞分类的进一步研究方法。     

计算机程序基因技术初探

计算机程序基因技术是在恶意程序不断演化与检测识别技术的对抗博弈中发展起来的,传统的恶意程序检测技术已难以应对恶意程序的快速动态增长趋势,计算机程序基因技术开启了恶意程序检测分析的一个新的思路,从汇编指令层中萃取出计算机程序的真实行为意图,从而对程序进行分析和识别。根据给出的计算机程序基因的定义以及提取方法,可以找出计算机程序最本原的特征,有效提高新型的或变种的恶意程序的分析和检测效率。     

Investigation of the restricted problem of three bodies of variable masses using computer algebra

The classical restricted three-body problem for bodies with variable masses is discussed for the case when the masses of two bodies vary isotropically at different rates and their sum varies according to the joint Meshchersky law. Within the perturbation theory in Hills’s approximation, differential equations determining the secular perturbations of the orbital elements are obtained and it is shown that they are integrable under arbitrary laws governing the mass variations satisfying the joint Meshchersky law. The influence of the variations of the body masses on the evolution of the orbital parameters is comparable with the perturbations created by massive bodies. All symbolic computations are performed in Wolfram Mathematica.     

On-line identification of a heat exchanger with a process computer—A case study

For on-line identification and parameter estimation of industrial processes with process computers an identification program package was developed. Three appropriate identification methods can be selected: recursive least squares, recursive instrumental variables and recursive correlation analysis with least squares. The program package also includes: signal generation, determination of model order and time delay, data filtering for the elimination of low frequent disturbances, model verification and plotting of intermediate and final results. Practical results and comparisons with the identification package are shown for an industrial size steam-heated heat exchanger.     

A study of personal computer utilization by managers

Personal computer (PC) utilization has become an important concern due to the PC's widespread and rapid implementation in the work place. A field study evaluated the responses of 105 managers who were PC users. The research model viewed PC utilization as a function of organizational, personal, computer system, and process attributes. Analysis was performed using Pearson correlations and one-way analysis of variance. The two items with the strongest and most consistent correlation with reported computer use time were user satisfaction with (1) the computer system's contribution to job performance and (2) their level of competence with the system. These findings suggest that PC utilization can be interpreted as a function of its perceived costs and benefits.     

Touchscreen usage in plant computer systems: A case study

This paper describes one electric utility's implementation of touch technology on the operator interface of selected plant computer systems. Specifically described is the implementation of scanning infrared touch CRT's on the man/machine interface for the Plant Information Computer System (PICS) and the Performance Monitoring System (PMS). These systems utilize modular software packages developed by Southern Company Services, Inc. (SCSI),¹ Birmingham, Alabama. In addition, SCSI performs hardware integration, system installation, and startup. The systems described herein have been installed at various electric- generating units at Alabama Power Company.¹ The PICS system is a minicomputer-based system performing real-time data acquisition, graphic display, alarming, logging, performance calculations, and data base maintenance in an electric-generating plant environment. The PMS system is a microcomputer-based system performing similar functions as above, but emphasizing plant performance calculations and associated displays. This paper presents an overview of current touch technologies, describes the reasons why scanning infrared beam technology was chosen for use on the PICS and PMS systems, outlines the software methodology used in conjuction with touch input, and lists operator feedback and conclusions draw since system installation.     

A computer study of systematic sound symbolism in classical Japanese verse

The analysis of sound symbolism in poetry is one of the more promising applications of computational methods. This paper proposes using database software with spreadsheet capabilities to give maximum versatility in the examination of consonant alliteration. In this case the database is drawn from a 10th century anthology of classical Japanese verse called theKokinshû. In recent years scholars have pointed out a few obvious examples of sound symbolism inKokinshû poetry. This study attempts to show that with these few notable exceptions, poetry of the period seems to have striven toward a balance in sound, avoiding techniques such as word initial alliteration which might call attention to itself.Jon W. LaCure is an Assistant Professor of Japanese in the Department of Romance and Asian languages and Literatures at the University of Tennessee, Knoxville. His major research interest is in the rhetorical devices of classical Japanese verse. He is currently working on a book with the title:The Structure of Japanese Poetry: Implications of the Poetics of the Kokinshu.     

Decision-making using computer conferencing: a case study

In January 1991, the members of the Centre for the Study of Management Learning at Lancaster University replaced their monthly departmental meetings with an online conference for a six-month trial. The paper describes the procedures followed and reviews the experience of department members and the effect of using the conference on discussions of departmental business, planning and decision-making. Advantages and disadvantages of using conferencing for this purpose are discussed in relation to a democratic approach to work and working relationships. Of particular interest was the way the change interacted with the ethos of the department.     

The use of a computer simulation to promote conceptual change: A quasi-experimental study

This mixed-methods investigation compared the effectiveness of three instructional approaches in achieving desired conceptual change among early childhood preservice teachers (n = 157). Each of the three treatments employed inquiry-based instruction on moon phases using data collected from: (1) the planetarium software program, Starry Night™, (2) nature observations and Starry Night™, or (3) nature observations alone. Data sources included drawings, intensive interviews, and a lunar shapes card sort. The data sets were analyzed via a constant comparative method in order to produce profiles of each participant’s pre- and post-instruction conceptual understandings of moon phases. Non-parametric tests of significance revealed that pre- to post-instruction gains were significant for all three treatments across all targeted concepts. The Starry Night™-Only treatment demonstrated statistically greater gains for sequencing moon phases than the other two treatments. However, there were no significant differences among the three treatments in regard to participants’ abilities to draw scientific moon shapes or in their conceptions of the causes of moon phases. Thus, the three treatments were equally effective in facilitating desired conceptual change.     

Technological and organizational change in the Brazilian computer industry: A case study

Abstract

This article gives an account of the results of a case study undertaken at a pioneer and particularly prominent firm in the Brazilian computer industry: COBRA — Computadores e Sistemas Brasileiros SA.

The study is part of a research project¹ whose main goal is the identification of viable organizational and technological options that could enhance the performance of firms in the Brazilian electro‐electronics industry. Among the more important findings, it was observed that the firm has the potential to evolve to a more flexible structure, in keeping with the new requirements of the probable future market scenarios within its sector.

Everything indicated, however, that the main constraining factors for bringing about such a structure were connected with the firm's culture and beliefs and with the indirect influence of the National Policy of Information Technology upon these. An hypothesis was put forward for an organizational model, and the necessary supportive computerized technology, which could be particularly appropriate in view of the impending deregulation, of the Brazilian computer industry. Also, in the scope of the current discussion on the restructuring of this industry in terms of a greater concentration, an alternative to the prevailing school of thought was proposed, and for whose success the organizational model at issue purports to be particularly relevant.     

A two-phase procedure for the study of computer network reliability in automated manufacturing systems

This paper presents a mathematical model for analyzing computer networks in production systems. The manufacturing facility, which is considered to be the main part of a production system is controlled by a computer network. Every station within a production system is assumed to have a computer and a network interface unit (NIU) as part of the overall computer network. For the system to remain operational, the computer network along with the manufacturing facilities should be extremely reliable. In this paper, we studied the reliability of the former, the computer network. The manufacturing facility is assumed to be reliable. Since every station must be operational for the whole system to function, failure in any network unit (computer of NIU) will halt the system production. For such systems the topology is logically equivalent to that of a system whose stations are connected in series. Hence, series reliability formulae is appropriate for these systems. In other systems, back-up (or stand-by) units are added to the computer and/or to the NIU to enhance the reliability. We consider our model to be a generic one because the reliability analysis it uses is independent of the network topology. It assumes constant failure rates for network components and uses a two-pass procedure in determining the effect of network reliability on the total system cost. A case study is presented to illustrate the importance of reliability considerations during the network design phase. Our analysis of the network reliability reveals that, in most cases, the incremental cost due to network failures will justify the additional units.     

An experimental study of relative throughput in a multiprocessor computer system

This paper describes the results of controlled experiments with a Honeywell H6000 series multiprocessor computer system, 212 experiments were performed using 14 test workloads on 8 H6000 configurations. The number of processors varied from 1 to 4, system controller units (SCUs) from 1 to 4, and main memory from 256K to 1024K words. The ratio (P) of I/O time and CPU time for the test workloads varied from 0.01 to 5.07. The improvement in throughput is expressed in terms of relative throughput (φ), defined as the ratio of elapsed time for a given test workload on a single-processor configuration to that on a multiprocessor configuration. The relative throughput increased monotonically with an increase in the number of processors for test workloads in the range 0<P<0.4 (CPU-bound) and φ exhibited an asymptotic behaviour for test workloads in the range 0.4<P<5.07 (I/O-bound).     

中国象棋计算机博弈开局库研究与设计

开局库是一种为了增强计算机的博弈水平而必不可少的辅助手段，开局阶段的着法采用查询数据库的方式生成，从而避免耗时的搜索、评估和出现战略性错误．研究了中国象棋机器博弈系统中应用开局库的一些技术问题．介绍了开局库的计算机自动生成方法，对统计开局库作了详细的探讨和论述，提出了理想开局库的设计思想以及开局库评估系统的必要性．     

Teaching computer music in a computer setting

Using a computer to produce sound in the classroom is not new and has been used for ear training and drill-and-practice for some time. Computer music can also provide computer students with an alternative means to explore traditional computer concepts: modular design, functional decomposition, and iterative development. Combining these uses for computer music would produce a course where both computer students and music students could gain an insight to the use of system development techniques. Such a course is described in this paper along with notes on how this course was implemented.     

Planning computer memory allocation: A simulation case study

A simulation of the main memory of the computer system of a large manufacturing organization is described. The impact of adding a new software package (namely CICS) on average memory usage is analyzed. The effect of adding memory capacity on memory utilization is also described.