开放条件下计算机实验室的硬盘数据保护之探讨

实验室是培养学生创新精神和实践能力的教学基地。计算机实验室大多是开放运行的,但是由于误操作、病毒及恶意破坏,经常造成计算机的硬盘数据丢失,给计算机实验室管理和维护带来很大的因难,寻找一种方便快捷、行之有效的保护方法成为迫切需求是很有必要的,为此,重点介绍了硬盘保护卡的使用方法,以保证实验室开放条件下计算机硬盘数据的保护。     

The Impact of Electronic Communication and Social Media on Child Welfare Practice

One hundred and thirty-six child welfare workers completed an online survey examining their experiences regarding the impact that electronic communication and social media use has had on their practice with youth and families. Workers reported e-mail and text message use have made work with youth easier, yet distinct difficulties have emerged for practitioners in relation to electronic communication and social media use. New elements have also emerged including issues with harassment and the ethics related to monitoring clients' online activities. Comparisons with a previous study conducted by Finn indicate that the use of technology within social work practice has evolved over time. Implications for social work practice and future research are also discussed.     

A Critical Reflection on the Experimental Method for Planning Research: Testing the Added Value of PSS in a Controlled Environment

For planning research to successfully generate usable mechanisms for planning practitioners more hypothesis-testing research designs are needed. Currently, the academic field seems more geared toward generating hypotheses, either by observing practice or from theoretical studies. This approach is especially common in research that generates knowledge of planning. In this paper, I map several relevant research designs that allow for such hypothesis testing and discuss their usability in planning research. Then, I particularly focus on the experimental method as a promising design for generating contextualized mechanisms for planning practice. I describe and analyze a study that aimed to develop mechanisms about the added value of knowledge technologies for the quality of planning. Two consecutive experiments are described in detail, after which the usability of the experimental method for planning research is discussed. Reflecting on these experiments indicate that the main strength of this research design is that it allows to create ideal circumstances for falsification (which is virtually impossible in planning practices. The main weakness is the ecological validity of findings, especially when the research is executed with students.     

Number of matches and matched people in the birthday problem

The well known birthday problem asks for the probability of at least one match out of a group of n people. Also of interest are the number of matches and the number of matched people. In this paper the means and variances of the number of matches and matched people are obtained. A generalization of the use of these methods to computer storage analysis is discussed.     

TESTING SUBHYPOTHESES AND ESTIMATING σ2 IN THE NONREPLICATED THREE-WAY MULTIPLICATIVE INTERACTION MODEL

ABSTRACT

Standard statistical techniques do not provide methods for analyzing data from nonreplicated factorial experiments. Such experiments occur for several reasons. Many experimenters may prefer conducting experiments having a large number of factor levels with no replications than conducting experiments with a few factor levels with replications particularly in pilot studies. Such experiments may allow one to identify factor combinations to be used in follow-up experiments. Another possibility is when the experimenter thinks that an experiment is replicated when in fact it is not. This occurs when a naive researcher believes that sub-samples are replicates when in reality they are not. Nonreplicated two-way experiments have been extensively studied. This paper discusses the analysis of nonreplicated three-way experiments. In particular, estimation of σ² is discussed and a test is derived for testing whether three-factor interaction is absent in sub-areas of three-way data using a nonreplicated three-way multiplicative interaction model with a single multiplicative term. Approximate null distribution of the derived test statistic is studied using Monte Carlo studies and results are illustrated through an example.     

A simple approximation of the sampling distribution of least absolute residuals regression estimates

For multivariate regression with a symmetric disturbance distribution, the error in the least absolute residuals estimator is approximately multivariate normally distributed with mean zero and variance matrix λ²(X′X)^?1, where X is the matrix of K explanatory variables and T observations, and λ ²/T is the variance of the median of a sample of size T from the disturbance distribution. The approximate sampling theory is validated by extensive Monte Carlo studies, and some directions of possible refinement emerge.     

A new model and class of designs for mixture experiments with process variables

Experiments that involve the blending of several components are known as mixture experiments. In some mixture experiments, the response depends not only on the proportion of the mixture components, but also on the processing conditions, A new combined model is proposed which is based on Taylor series approximation and is intended to be a compromise between standard mixture models and standard response surface models. Cost and/or time constraints often limit the size of industrial experiments. With this in mind, we present a new class of designs that will accommodate the fitting of the new combined model.     

计算机技术在书刊编辑中的运用

近年来计算机应用技术在书刊编辑中的涉及范围越来越广,然而怎样更好地将计算机技术与出版编辑工作有效地结合在一起,让两者能够运用得更加自如,是一个值得深入思考和解释的问题。结合个人多年来的实践工作经验,就计算机在书刊编辑中的运用技术展开探讨,希望能够起到抛砖引玉的作用。     

Designing and analyzing a mixture experiment to optimize the mixing proportions of polyvinyl chloride composites

Polyvinyl chloride (PVC) products are typically complex composites, whose quality characteristics vary widely depending on the types and proportions of their components, as well as other processing factors. It is often required to optimize PVC production for specific applications at the highest cost efficiency. This study describes the design and analysis of a statistical experiment to investigate the effects of different parameters over the mechanical properties of PVC intended for use in electrical wire insulation. Four commonly used mixture components, namely, virgin PVC, recycled PVC, calcium carbonate, and a plasticizer, and two process variables, type of plasticizer and filler particle size, were examined. Statistical tools were utilized to analyze and optimize the mixture while simultaneously finding the proper process parameters. The mix was optimized to achieve required strength and ductility, as per ASTM D6096 while minimizing cost. The paper demonstrates how statistical models can help tailor complex polymeric composites in the presence of variations created by process variables.     

Spreadsheet Analysis in Human Services

Abstract

Computerized spreadsheets were developed to support accounting functions, but these programs have come to have much broader applications. This chapter introduces spreadsheet analysis, briefly explains key concepts used in creating spreadsheets, and finally gives examples from direct practice and human service administration. While spreadsheets can be used for any task that requires manipulation of numbers or use of a calculator, they are most useful in producing charts and tables and for modeling problems requiring “what if” projections.