基于2PLM项目参数估计的病态矩阵控制

病态矩阵是IRT理论中项目参数估计必然面对的问题．本文以2PLM参数估计为例．推导出参数估计迭代公式，系统阐述了三种病态控制方法的原理及在编程中数据处理的技巧。     

Can Computer Use Hurt Science Achievement? The USA Results from PISA

A surprising result of the Third International Mathematics and Science Study (TIMSS) is that computer use was negatively associated with high student achievement in some countries. More specifically, the students from all three countries who indicated that they use computers in the classroom most frequently were those with the lowest achievement on the TIMSS in 1995. For the purpose of this study, a similar comparison was made for 15-year-old U.S.A. students, based on the data from the Program for International Student Assessment (PISA). The results of this study show that it is not computer use itself that has a positive or negative effect on the science achievement of students, but the way in which computers are used. For example, after controlling for the student's socioeconomic status in the United States of America, the results indicated that the students who used computers frequently at home, including for the purpose of writing papers, tended to have higher science achievement. However, the results of this study also show that science achievement was negatively related to the use of certain types of educational software. This indicates a result similar to that found in the TIMSS data, which might reflect the fact that teachers assign the use of the computer and of educational software to the lower achieving students more frequently, so that these students can obtain more personal and direct feedback through educational software.     

企业目标:经济学与财务管理学的分歧与评析

利润最大化是经济学公认的企业目标,但财务管理学中不存在一个一致认同的目标,且大多都以企业价值最大化作为目标。相比于所有其他财务目标,利润最大化既是其他目标得以实现的前提条件,又是一个统帅性和决定性目标,因此企业财务管理也应以利润最大化为目标。     

初探现代学徒制机器人专业人才培养方案的制订

现代学徒制人才培养方案是学徒制的核心内容,那么如何制订现代学徒制专业人才培养方案?本文以工业机器人专业为例,较详细地介绍了人才培养方案的制订过程。     

用89C51单片机产生二位式伪随机信号(PRBS)的程序设计

本文着重讨论用GMS97C1051单片机产生二位式伪随机信号（PRBS）的程序设计。     

电视多媒体制作播出数字网络的构思

该文介绍了以太网与FC网组成的双网结构的电视多媒体制作播出数字网络的一种构思 ,并且针对其主要功能作出说明     

Application of the Bayes’ theory to the failure rate evaluation of electrical apparatus

The Weibull distribution has been widely used in reliability fields. A mixed Weibull distribution represents a popu- lation that consists of several Weibull subpopulations. In this paper, a new approach which combines the least-squares method with Bayes’ theorem, takes advantage of the parameter estimation for single Weibull distribution is developed to estimate the pa- rameters of each subpopulation. The estimates given by this paper also satisfy the maximum likelihood equation. The estimates of the failure rate of the mixed Weibull population are given. An actual test data is computed by using the proposed method. The Kolmogorov-Smirnov goodness-of-fit test turns out that the proposed method yields more accurate result.     

Chaotic phenomenon and the maximum predictable time scale of observation series of urban hourly water consumption

The chaotic characteristics and maximum predictable time scale of the observation series of hourly water consumption in Hangzhou were investigated using the advanced algorithm presented here is based on the conventional Wolf's algorithm for the largest Lyapunov exponent. For comparison, the largest Lyapunov exponents of water consumption series with one-hour and 24-hour intervals were calculated respectively. The results indicated that chaotic characteristics obviously exist in the hourly water consumption system; and that observation series with 24-hour interval have longer maximum predictable scale than hourly series. These findings could have significant practical application for better prediction of urban hourly water consumption.     

So You Want to Be a Mentor? An Analysis of Mentor Competencies

As the need for mentors continues to expand in order to meet organizational and programmatic needs, so does the need for quality mentoring. Although sometimes an immediate need for quantity may foreshadow quality, this should not be the case when utilizing mentoring to achieve goals. Faculty mentor competencies are analyzed to demonstrate the importance and need for competent mentors in formal mentoring programs, specifically those in higher education. Correlation analysis is used to assess the relationship between research-based mentor competencies and Ronald E. McNair Program goals. Findings support the need for mentor competency assessment, usage of competent mentors, additional development of mentor competency models, and further study.     

水泥机立窑煅烧过程微机控制系统的软件抗干扰技术

本文以Z80微机为例,介绍了三种软件抗干扰技术:数字滤波、重复输出和设立陷井。