Robust Classification for Imprecise Environments

In real-world environments it usually is difficult to specify target operating conditions precisely, for example, target misclassification costs. This uncertainty makes building robust classification systems problematic. We show that it is possible to build a hybrid classifier that will perform at least as well as the best available classifier for any target conditions. In some cases, the performance of the hybrid actually can surpass that of the best known classifier. This robust performance extends across a wide variety of comparison frameworks, including the optimization of metrics such as accuracy, expected cost, lift, precision, recall, and workforce utilization. The hybrid also is efficient to build, to store, and to update. The hybrid is based on a method for the comparison of classifier performance that is robust to imprecise class distributions and misclassification costs. The ROC convex hull (ROCCH) method combines techniques from ROC analysis, decision analysis and computational geometry, and adapts them to the particulars of analyzing learned classifiers. The method is efficient and incremental, minimizes the management of classifier performance data, and allows for clear visual comparisons and sensitivity analyses. Finally, we point to empirical evidence that a robust hybrid classifier indeed is needed for many real-world problems.     

Empirical Evaluation of User Models and User-Adapted Systems

Empirical evaluations are needed to determine which users are helped or hindered by user-adapted interaction in user modeling systems. A review of past UMUAI articles reveals insufficient empirical evaluations, but an encouraging upward trend. Rules of thumb for experimental design, useful tests for covariates, and common threats to experimental validity are presented. Reporting standards including effect size and power are proposed.     

Automatic Real-Time Analysis of Reactive Systems with the PARTS Toolset

Real-time systems are becoming increasingly widespread, often in safety-critical applications. It is therefore crucial that these systems be correct; however, there are few automated tools for analyzing concurrency and timing properties of these systems. The PARTS toolset uses a Petri-net-based reachability analysis to analyze program specifications written in an Ada-83 subset. Our simple time Petri nets are specifically aimed at facilitating real-time analysis. In order to control the state-explosion problem, PARTS employs several optimization techniques aimed at state-space reduction. In this paper we discuss our approach and we report on extensive experiments with several examples of real-time specifications based on Ada 83. When possible, we also compare our experimental results with results obtained by other approaches to real-time analysis.     

Subjective evaluation of software evolvability using code smells: An empirical study

This paper presents the results of an empirical study on the subjective evaluation of code smells that identify poorly evolvable structures in software. We propose use of the term software evolvability to describe the ease of further developing a piece of software and outline the research area based on four different viewpoints. Furthermore, we describe the differences between human evaluations and automatic program analysis based on software evolvability metrics. The empirical component is based on a case study in a Finnish software product company, in which we studied two topics. First, we looked at the effect of the evaluator when subjectively evaluating the existence of smells in code modules. We found that the use of smells for code evaluation purposes can be difficult due to conflicting perceptions of different evaluators. However, the demographics of the evaluators partly explain the variation. Second, we applied selected source code metrics for identifying four smells and compared these results to the subjective evaluations. The metrics based on automatic program analysis and the human-based smell evaluations did not fully correlate. Based upon our results, we suggest that organizations should make decisions regarding software evolvability improvement based on a combination of subjective evaluations and code metrics. Due to the limitations of the study we also recognize the need for conducting more refined studies and experiments in the area of software evolvability.

An approach to evaluation of hierarchical systems performance

An approach to assessment of performance of hierarchical systems with simple subordination is developed with regard to moment characteristics of sequences of random sums. Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 70–79, July–August, 2000.     

A Replicated Empirical Study of the Impact of the Methods in the PSP on Individual Engineers

The Personal Software Process (PSP) has during the last couple ofyears gained attention as a way to individual improvements insoftware development. The PSP is introduced to students and engineersthrough a course, which introduces a personal software developmentprocess. The personal software development process is improvedin steps during the course and a collection of methods is introducedto support the personal development process. The question is,however, how do these methods influence the performance of anindividual engineer? This question has been studied in a studymade at the Software Engineering Institute, and the study hasshown that the methods in the PSP have a positive effect on theperformance of the individuals. There is however a need to replicatethis study to confirm the findings in other settings and withother individuals. This paper describes a replicationof the study made at the Software Engineering Institute. Boththe original study and this replication are made on data reportedfrom the students taking the PSP course. The differences betweenthe two studies are the programming languages used, which heldthe courses, the class sizes, and the experiences of the students.In summary, the results from this replication confirm the resultsin the original study: Size estimation accuracy gets better,the defect density gets lower, the defects are found earlierand that the pre-compile yield gets better during the PSP course.Basically, the two studies show that the methods in the PSP helpengineers to improve their performance.     

包钢连铸机计算机控制系统(Ⅱ)

3二级计算机系统 3.1系统配置 系统硬件配置如图 2所示.主机选用 DEC公司 ALPHA AXP DEC 3000/600S小型机,服务器选用 INFO-SERVER 1000,该系统以集线器 DEC hub90为中心组成星形网络通信系统.共主要软件有： OPEN VMS/HANZI V6.0操作系统;在 OPEN VMS AXP环境下的系统管理软件 MSV,记录管理软件 RMS,开发图形用户界面的 DEC WINDOWS MOTIV/HANZI和 GUIMAN; MOTIV公司自行开发的系统应用开发工具包 Case system MODAS. 3.2应用软件结构和功能 包钢引进的连铸机二级计算机系统应用软件,是由 MANN…     

甲壳素改性产品的提取制备工艺的研究

甲壳素等相关改性产品作为目前发展迅速的新型材料，有着及其广泛的应用。本文主要对甲壳素的提取制备工艺及改性产品生产的优化条件进行了试验及分析研究，得出了具有较高经济效益的生产方法。     

彗星试验在农药安全评价中的应用

彗星试验(Comet assay)，又称单细胞凝胶电泳试验(SCGE)，是一种快速、简便、灵敏的检测单个细胞DNA断裂的新技术，由于其具备其它试验无可比拟的优越性，因此应用前景十分广泛。本文就该技术的原理、操作程序和方法作一介绍，并预测其在农药安全评价中将有广阔的应用前景。