基于加权案例推理模型族的软件成本SVR组合估算

精确地估算软件成本是软件项目成功开发的一个重要保证,直接影响着软件的风险控制和质量保证.为了更好地解决单一估算模型的不足,提出了集成多案例推理(CBR)模型的软件成本组合估算模型.首先,采用六种距离计算公式刻画新旧项目相似度,构建了六种CBR模型,并运用粒子群算法(PSO)来优化CBR模型族中的属性权重.其次,在CBR模型族的基础上,运用支持向量回归机(SVR)模型将不同CBR模型的估算结果进行集成,提高软件成本估算结果的精度.利用Deshamais数据库对模型有效性进行检验,实证结果表明,在六种CBR模型中Euc-CBR、Min-CBR、Gau-CBR和Mah-CBR模型估算结果没有明显差异,Gre-CBR和Man-CBR模型略优;提出的SVR组合估算模型估算精度明显优于单CBR模型和其他线性组合估算模型,能有效提高软件成本的估算精度.     

不对称信息下信息技术服务外包合同设计

本文针对客户企业向IT供应商外包信息技术服务这一背景,考虑IT供应商不仅具有开发信息系统能力的私有信息,且其开发过程中的努力行为对于客户企业不可见的情况,研究了客户企业信息技术服务外包合同设计问题。研究发现,不对称信息下,客户企业可以通过设计最优合同菜单来甄别不同能力的IT供应商,但是此时客户企业需要向高能力IT供应商支付信息租金。同时,客户企业可以通过设计最优合同有效规制高能力IT供应商系统开发过程中的努力行为,但是相比于信息对称的情况,不对称信息下低能力IT供应商会存在努力不足的现象。低能力IT供应商努力不足的现象会降低社会福利和客户企业的期望利润;客户企业向高能力IT供应商支付信息租金的行为也会减少客户企业的期望利润。增加系统调试阶段的调试时间或者选择信息系统故障检出率高的IT供应商,可以降低高能力IT供应商的信息租金,并缓解低能力IT供应商努力不足的现象,进而减少信息不对称给客户企业带来的利润损失。     

正交优化法的软件设计及其应用

本文用BASIC语言编制了正交优化法软件，并通过实例对其应用进行探讨，研究结果表明：用正交优化法处理化学、环保等方面的非线性模型的参数估值和非线性回归问题是非常有效的。     

体育保健学CAI积件系统开发之我见

根据最新的CAI研究方向 ,提出体育保健学积件系统设计模型 ,并对开发中的难点、对策进行了说明 ,为体育保健学的教学改革提供参考     

宽带数字下变频的高效实现方法研究

针对软件无线电接收机中数字下变频的特点,提出了一种合理的基于FPGA实现宽带数字下变频的方案,即分级实现以降低抗混叠滤波器的阶数;并且每级采用不同算法实现滤波抽取以占用不同资源,从而实现FPGA总体资源的合理、高效利用。另外,论述了一种适合FIR抽取滤波器的算法——时钟选择运算法,并通过Altera公司的EP2S60F484C4对该算法进行了测试,验证了它的高效性。     

Structural Nested Models and Standard Software: A Mathematical Foundation through Partial Likelihood

Abstract.  In observational studies treatment may be adapted to the patient's state during the course of time. These covariates may in turn also react on the treatment under study, and so on. This makes it hard to distinguish between treatment effect and selection bias. Structural nested models aim at estimating treatment effect in such complicated situations, even when treatment may change at any time. We show that structural nested models can often be calculated with standard software, by using standard models to predict treatment as a tool to estimate treatment effect. Robins ( Survival analysis, Volume 6 of Encyclopedia of Biostatistics , John Wiley and Sons, Chichester, 1998) conjectured this, but so far it was unproven. We use a partial likelihood approach to choose the estimators and tests as a subclass of the estimators and tests in Lok (math. ST/0410271 at http://arXiv.org , 2004). We show that this is the class of estimators and tests that can be calculated with standard software. The estimators are consistent and asymptotically normal, and have interesting asymptotic properties.     

Use of multiple cluster analysis methods to explore the validity of a community outcomes concept map

Concept mapping is now a commonly-used technique for articulating and evaluating programmatic outcomes. However, research regarding validity of knowledge and outcomes produced with concept mapping is sparse. The current study describes quantitative validity analyses using a concept mapping dataset. We sought to increase the validity of concept mapping evaluation results by running multiple cluster analysis methods and then using several metrics to choose from among solutions. We present four different clustering methods based on analyses using the R statistical software package: partitioning around medoids (PAM), fuzzy analysis (FANNY), agglomerative nesting (AGNES) and divisive analysis (DIANA). We then used the Dunn and Davies-Bouldin indices to assist in choosing a valid cluster solution for a concept mapping outcomes evaluation. We conclude that the validity of the outcomes map is high, based on the analyses described. Finally, we discuss areas for further concept mapping methods research.     

Notes on authors

Social network analysis (SNA), a method which can be used to explore networks in various contexts, has received increasing attention. Drawing on the development of European smoke-free policy, this paper explores how a mixed-method approach to SNA can be utilised to investigate a complex policy network. Textual data from public documents, consultation submissions and websites were extracted, converted and analysed using plagiarism detection software and quantitative network analysis and qualitative data from public documents and 35 interviews were thematically analysed. While the quantitative analysis enabled understanding of the network’s structure and components, the qualitative analysis provided in-depth information about specific actors’ positions, relationships and interactions. The paper establishes that SNA is suited to empirically testing and analysing networks in EU policy-making. It contributes to methodological debates about the antagonism between qualitative and quantitative approaches and demonstrates that qualitative and quantitative network analysis can offer a powerful tool for policy analysis.     

An Evaluation of Simulations in Developmental Disabilities (SIDD): Instructional Software that Provides Practice in Behavioral Assessment and Treatment Decisions

ABSTRACT

Simulations in Developmental Disabilities (SIDD) is a multimedia computer program designed to provide undergraduate psychology students with practice in making assessment and treatment decisions. Eighteen undergraduate psychology students participated in an experiment to test the instructional effectiveness of SIDD. Post-test scores were significantly higher in the experimental group who received training with SIDD than in a control group who did not receive training. The students also rated the software positively. Future strategies to further evaluate the software are discussed.