Automatically Restructuring Programs for the Web

This paper explains how to automatically transform a batch program into a standard CGI program. The transformation preserves the program's behavior even if consumers use the back button or the window-cloning facilities of their Web browsers. The paper demonstrates the workings of the transformation for both Scheme and C programs and discusses how it applies to any full-fledged programming language.     

计算机软件测试研究

计算机系统软件性能测量是计算机系统性能评价的重要手段。文章讨论了使用程序监视器对软件的覆盖率、执行时间、内存占用情况进行测试,分析程序结构和数据结构,并针对其性能瓶颈,提出了对程序进行改进的方法,从而提高程序代码的质量和性能,保证软件可靠高效运行。     

Tools for distributed application management

The issues of managing distributed applications are discussed, and a set of tools, the meta system, that solves some longstanding problems is presented. The Meta model of a distributed application is described. To make the discussion concrete, it is shown how NuMon, a seismological analysis system for monitoring compliance with nuclear test-ban treaties is managed within the Meta framework. The three steps entailed in using Meta are described. First the programmer instruments the application and its environment with sensors and actuators. The programmer then describes the application structure using the object-oriented data modeling facilities of the authors' high-level control language, Lomita. Finally, the programmer writes a control program referencing the data model. Meta's performance and real-time behavior are examined     

Investigating attributes affecting the performance of WBI users

Numerous research studies have explored the effect of hypermedia on learners' performance using Web Based Instruction (WBI). A learner's performance is determined by their varying skills and abilities as well as various differences such as gender, cognitive style and prior knowledge. In this paper, we investigate how differences between individuals influenced learner's performance using a hypermedia system to accommodate an individual's preferences. The effect of learning performance is investigated to explore relationships between measurement attributes including gain scores (post-test minus pre-test), number of pages visited in a WBI program, and time spent on such pages. A data mining approach was used to analyze the results by comparing two clustering algorithms (K-Means and Hierarchical) with two different numbers of clusters. Individual differences had a significant impact on learner behavior in our WBI program. Additionally, we found that the relationship between attributes that measure performance played an influential role in exploring performance level; the relationship between such attributes induced rules in measuring level of a learners' performance.     

基于受限行为约束策略的桌面计算系统交互性能测量方法

测量桌面计算系统的交互性能是分析和改进系统性能的重要基础.方便地获得准确测量结果的难点是如何确定输入事件和其直接触发的输出事件之间的对应关系.为此,提出一种采用受限行为约束策略的交互性能测量方法,首先分析了确定输入、输出事件的对应关系需要满足的约束条件,通过会话录制辅助机制合理转化难以满足约束条件的事件,通过用户行为检验机制进一步确认所有事件已经满足约束条件,从而保证可以获得更准确的测量结果.基于该方法,实现了一个支持Windows和Linux等主流桌面计算系统的测量工具VNC-IPA.实验以"慢动作"基准测量A-法获得的测量结果为真值,结果表明,相比其他交互性能测量工具VNCplay,使用VNC-IPA获得的测量结果的相对误差平均降低了35.4%.     

Studying inquiry learning with FILE

The FILE program (flexible inquiry learning environment) is a research tool, which allows researchers in inquiry learning to design and administer learning tasks in which task domain and task model (i.e. the relations between input and output variables) can be adjusted independently, while other factors (e.g. interface) are held constant. Its monitoring facilities allow for on-line measurement of learning behavior. This paper offers one example of the possibilities FILE has to offer to researchers. Data are presented which illustrate the sensitivity of FILE to age differences in inquiry learning outcome and processes. Instructional applications of FILE are also discussed.     

程序复杂性度量的一种新方法

通过分析传统的程序复杂性度量方法的不足之处，首先提出了一种基于程序分解机制的路径复杂性度量方法，然后给出了计算路径复杂度的算法，最后给出了实例。新的度量方法指出了一个程序需要的完全测试路径数目。     

Discovering and exploiting program phases

Understanding program behavior is at the foundation of computer architecture and program optimization. Many programs have wildly different behavior on even the largest of scales (that is, over the program's complete execution). During one part of the execution, a program can be completely memory bound; in another, it can repeatedly stall on branch mispredicts. Average statistics gathered about a program might not accurately picture where the real problems lie. This realization has ramifications for many architecture and compiler techniques, from how to best schedule threads on a multithreaded machine, to feedback-directed optimizations, power management, and the simulation and test of architectures. Taking advantage of time-varying behavior requires a set of automated analytic tools and hardware techniques that can discover similarities and changes in program behavior on the largest of time scales. The challenge in building such tools is that during a program's lifetime it can execute billions or trillions of instructions. How can high-level behavior be extracted from this sea of instructions? Some programs change behavior drastically, switching between periods of high and low performance, yet system design and optimization typically focus on average system behavior. It is argued that instead of assuming average behavior, it is now time to model and optimize phase-based program behavior.     

Building flexible real-time systems using the Flex language

The design and implementation of a real-time programming language called Flex, which is a derivative of C++, are presented. It is shown how different types of timing requirements might be expressed and enforced in Flex, how they might be fulfilled in a flexible way using different program models, and how the programming environment can help in making binding and scheduling decisions. The timing constraint primitives in Flex are easy to use yet powerful enough to define both independent and relative timing constraints. Program models like imprecise computation and performance polymorphism can carry out flexible real-time programs. In addition, programmers can use a performance measurement tool that produces statistically correct timing models to predict the expected execution time of a program and to help make binding decisions. A real-time programming environment is also presented     

Measuring and analyzing real-time performance

To satisfy the deadline requirements of hard real-time systems, programmers must be able to determine the maximum execution time of any task. The use of Flex, an experimental real-time language being developed for the Concord project, is examined. The Flex system embodies an empirical approach that first measures the actual timing behavior and then uses the measurement results to determine the parameters of a programmer-supplied timing model. This timing model gives the system the programmer's understanding of the program's timing behavior in terms of its asymptotic time complexity. The measurement system determines the exact values of model parameters using sophisticated statistical methods to derive the program's timing characteristics precisely. Flex is better than performance analyzers that examine only code because it can cope with more kinds of program structures and its does not depend on an underlying hardware model. The integration of measurement and formal analysis is discussed     

Performance measurement for parallel and distributed programs: astructured and automatic approach

Novel approaches are presented for designing performance measurement systems for parallel and distributed programs. The first approach involves unifying performance information into a single, regular structure that reflects the structure of programs under measurement. The authors define a hierarchical model for the execution of parallel and distributed programs as a framework for the performance measurement. A complete different levels of detail in the hierarchy. The second approach is based on the development of automatic guidance techniques that can direct users to the location of performance problems in the program. Guidance information from such techniques supplies facts about problems in the program and provides possible answers for the further improvement of program efficiency. A performance measurement system, called IPS, has been developed as a prototype of the authors' model and design. Some of the test results from IPS are also discussed     

Performance modeling for hierarchical graph partitioning in heterogeneous multi-core environment

Considering application behavior in graph partitioning is an arduous task because of the chicken-and-egg problem: the application behavior depends on how the graph is decomposed while achieving load balance requires the knowledge of how the application utilizes the underlying resources. Advances in multi-core processors further complicate the endeavor by introducing hardware diversity and intra-node contention. As an attempt to quantify performance for partitioning refinement, we propose a model that predicts execution times of iterative mesh-based applications running on heterogeneous multi-core clusters. Apart from considering resource heterogeneity, the model takes into account hierarchical communication characteristics, overlap between computation and communication, as well as performance penalties due to intra-node contention. We present a detailed methodology on how to obtain key parameters from a real system and highlight potential pitfalls of conventional approaches in obtaining the parameters. Experiments were conducted using a synthetic application benchmark solving a partial differential equation. Evaluation shows a good agreement between actual time measurement and the performance model.     

基于VC 6.0的PC机和单片机的接口设计

基于32位Windows操作系统的PC机和单片机间的串行通信是一种常见的通信方式.PC机与多单片机结合的测控系统越来越占主导地位.如何更好的在Windows平台下实现PC机与单片机的通信设计,成为测控系统中一个关键技术问题.为此,详细阐述了两种程序设计的方法.即,在VC 6.0中使用WindowsAPI函数编写程序和使用VC 自带的Microsoft Communications Control控件(即MSComm控件)编写程序.     

基于VC＋＋6.0的PC机和单片机的接口设计

基于32位Windows操作系统的PC机和单片机间的串行通信是一种常见的通信方式。PC机与多单片机结合的测控系统越来越占主导地位。如何更好的在Windows平台下实现PC机与单片机的通信设计,成为测控系统中一个关键技术问题。为此,详细阐述了两种程序设计的方法。即,在VC＋＋6.0中使用WindowsAPI函数编写程序和使用VC＋＋自带的Microsoft Communications Control控件（即MSComm控件）编写程序。     

Diagnosis of feedwater heater performance degradation using fuzzy inference system

Power generation facilities cannot avoid performance degradation caused by severe operating conditions such as high temperature and high pressure, as well as the aging of facilities. Since the performance degradation of facilities can inflict economic on power generation plants, a systematic method is required to accurately diagnose the conditions of the facilities.This paper introduces the fuzzy inference system, which applies fuzzy theory in order to diagnose performance degradation in feedwater heaters among power generation facilities. The reason for selecting only feedwater heaters as the object of analysis is that it plays an important role in the performance degradation of power generation plants, which have recently been reported with failures. In addition, feedwater heaters have the advantage of using many data types that can be used in fuzzy inference because of low measurement limits compared to other facilities. Fuzzy inference systems consists of fuzzy sets and rules with linguistic variables based on expert knowledge, experience and simulation results to efficiently handle various uncertainties of the target facility. We proposed a method for establishing a more elaborate system. According to the experimental results, inference can be made with consideration on uncertainties by quantifying the target based on fuzzy theory. Based on this study, implementation of a fuzzy inference system for diagnosis of feedwater heater performance degradation is expected to contribute to the efficient management of power generation plants.     

Measurement program success factors revisited

Success factors for measurement programs as identified in the literature typically focus on the ‘internals’ of the measurement program; incremental implementation, support from management, a well-planned metric framework, and so on. However, for a measurement program to be successful within its larger organizational context, it has to generate value for the organization. This implies that attention should also be given to the proper mapping of some identifiable organizational problem onto the measurement program, and the translation back of measurement results to organizational actions. We have extended the well-known ‘internal’ success factors for software measurement programs with four ‘external’ success factors. These success factors are aimed at the link between the measurement program and the usage of the measurement results. In this paper, we show how this combined set of internal and external success factors explains the success or failure of five industrial measurement programs.     

Implementing a software metrics program at Nokia

Model solutions for implementing a measurement program do not always fit an organization without tailoring. The sizes and maturities of the processes vary from organization to organization. In an organization with mature software processes, carefully adjusting the created solution for a measurement program to the environment-specific needs and options can save considerable effort. The article demonstrates the real-world application of the Nokiaway software metrics program and how it benefited in its divergence from a typical goal-question-metric approach     

Visualizing the Performance of SPMD and Data-Parallel Programs

Observing the activities of a complex parallel computer system is no small feat, and relating these observations to program behavior is even harder. In this paper, we present a general measurement approach that is applicable to a large class of scalable programs and machines, specifically SPMD and data-parallel programs executing on distributed memory computer systems. The combined instrumentation and visualization paradigm, called VISTA, is based on our experiences in programming and monitoring applications running on an nCUBE 2 computer and a MasPar MP-1 computer. The key is that performance data are treated similarly to any distributed data in the context of the programming models and presented via a hierarchy of multiple views. Because of the data-parallel mapping of program onto machine, we can view the performance as it relates to each processor, processor cluster, or the processor ensemble and as it relates to the data structures of the program. We illustrate the utility of VISTA by example.