共查询到19条相似文献，搜索用时 203 毫秒
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面向对象的软件开发日趋流行，它能够满足软件开发对于生产效率、可靠性、易维护性、易管理等方面的更高、更快、更强的迫切需求。面向对象的方法，把系统看作是相互协作的对象，这些对象是结构和行为的封装，都属于某个类，那些类具有某种层次化的结构。系统的所有功能通过对象之间相互发送消息来获得。 相似文献
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提出了一种新的多数据流聚类算法.该算法可以有效地对有相似行为但存在一定时间延迟的多数据流进行聚类.算法采用自回归模型技术度量数据流间的延迟相关,利用频谱估计来抽取数据流的特征.每一个数据流用其谱分量的和来表示,从而来计算每对数据流间的相关关系.每个谱分量用振幅、相位、衰减率、频率4个参数来描述.算法计算谱分量对之间的ε-延时相关关系,并以此为基础来得到聚类分析中数据流间距离的度量.此外,算法采用滑动窗口技术对多数据流进行聚类,实时地得出聚类结果且动态地调节聚类的个数.在人工数据集和实际数据集上的实验结果表明,所提出的算法比其他类似的算法具有更快的速度和更好的聚类效果. 相似文献
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为了在整个供电服务生命周期中做出各类关键决策调控,最终达到高的客户满意度,对供电服务系统的组成要素及其之间的关联关系进行分析并优化。借鉴质量管理中的SQFD方法,提出了5个一级16个二级供电服务顾客需求指标和6个供电服务技术需求指标,针对指标和关联关系提出数据采集和度量方法,构造出多指标融合的服务质量屋评价模型。以湖北十堰供电服务为实例,将顾客差异性评价观点融合形成多维度评价结果,对整个过程进行诊断和重新设计优化。 相似文献
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传统的IFPUG功能点分析方法对行业应用软件项目进行软件规模度量时,调整因子考虑的是系统整体特征。该方法对典型的管理信息系统较为有效,但当系统或者系统的部分模块具有一些其它技术特征时,度量结果会出现较大偏差。针对行业应用软件专业化和复杂化的特点,首先按照软件应用的业务流程和技术特征,对软件进行模块分解,针对不同模块分别考虑通用系统特征和调整因子,提出模块分解的基本过程和改进的通用调整因子计算方法;然后基于不同的模块权重计算加权后的功能点总数;最后利用上述方法选取了实际项目进行软件规模度量分析。实验结果表明,与传统的IFPUG功能点分析方法相比,改进后的功能点计算结果与项目实际功能点数更为接近。 相似文献
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王铁滨 《通化师范学院学报》2007,28(2):27-30
随着面向对象开发思想广泛应用到大规模的软件中,相应的对面向对象软件测试技术也提出了新的更高的要求.面向对象软件测试技术与传统软件测试相比,在测试步骤上基本相同,但是测试的思想截然不同,它的测试重点放在了类的测试问题上,与传统的单元测试相对应.因此,重点研究和探索了在类测试阶段,对于基于OSD动态状态测试模型的构造方法及其应用. 相似文献
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我们通常使用的刻度尺上每单位长度都标有刻度,它的主要作用就是用来度量物体的长度.其实,要达到这个目的,尺子上只需要有一些简单的刻度就可以了.例如,6 公分的长度可以在标有 1 公分的刻度处反复度量 6 次,当然,也可以在标有 2 或 3 公分的刻度处反复度量 3 次或 2 次.现在考虑这样一个有趣的问题,就是若不允许反复度量或累加的话,刻度尺上需要哪些刻度. 问题 1请在一条长为13厘米的无刻度的尺子上添加 4 个刻度,使之可以度量 1～13 之间任何整厘米长度的尺寸(注:度量指一次性量出,如 5 可以由刻度5 直接量出或由6 和 11间接量出,而不… 相似文献
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提出应该使用类而不是方法作为切片作用域来计算类的内聚性．首先,对一个给定的属性,找出每个方法中对该属性最后一次定义的语句．然后,以类为切片作用域计算这些语句相对于该属性的前向和后向数据切片,通过合并得到该属性的类数据切片．最后,在所有属性的类数据切片的基础上计算类的内聚性．与传统的以方法为切片作用域的内聚性度量相比,以类为切片作用域的内聚性度量考虑了类中方法之间可能存在的交互．实验结果表明,当使用类为切片作用域时,所得的度量值能更准确地量化类的内聚性． 相似文献
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本文采用统计分析方法研究词汇记忆策略与学习效果的关联关系.首先综述现有词汇记忆策略;然后以英语词汇记忆为例,进行数据调查,对记忆策略进行系统聚类;最后采用回归分析研究不同类别记忆策略与学习效果的关联关系.本文研究结果能帮助教学者对不同情形的学习者因材施教. 相似文献
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以理论研究的视角,现有面向对象程序设计语言的理论模型存在不足,如C++不支持元类,Java和C#的基本类型不是对象等.为此,设计了一种程序设计语言Shrek,将多种语言特性和语言设施统一在一个简洁、一致的模型下实现.Shrek语言是基于类的完全面向对象语言,拥有动态强类型系统,采用了与Mixin相结合的单继承机制.该语言具有协调一致的类对象结构,具备结构化计算反射能力,能够进行安全的元类程序设计.另外,它还支持多线程程序设计和自动垃圾回收,并通过本地方法机制极大地增强了自身的表达能力.该语言的原型系统已经实现,达到了预期的设计目标. 相似文献
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INTRODUCTION The increasingly complex and large number ofsoftware products in today’s software industrymakes the tasks of software maintenance, softwarereuse and software restructuring more and moredifficult. With the popularity of the object-orientedprogramming paradigm, the ability to reverse en-gineer and understand object-oriented legacy sys-tems has become an important problem to be ad-dressed. In the object-oriented reverse engineering(OORE) research area, most researchers f… 相似文献
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Classes are key software components in an object-oriented software system. In many industrial OO software systems,there are some classes that have complicated structure and relationships. So in the processes of software maintenance,testing,software reengineering,software reuse and software restructure,it is a challenge for software engineers to understand these classes thoroughly. This paper proposes a class comprehension model based on constructivist learning theory,and implements a software visualization tool(MFV-Class)to help in the comprehension of a class. The tool provides multiple views of class to uncover manifold facets of class contents. It enables visualizing three object-oriented metrics of classes to help users focus on the understanding process. A case study was conducted to evaluate our approach and the toolkit. 相似文献
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Sensitivity Analysis of the No-Omitted Confounder Assumption in Latent Growth Curve Mediation Models
Davood Tofighi Yu-Yu Hsiao Eric S. Kruger David P. MacKinnon M. Lee Van Horn Katie Witkiewitz 《Structural equation modeling》2019,26(1):94-109
Latent growth curve mediation models are increasingly used to assess mechanisms of behavior change. For latent growth mediation model, like any another mediation model, even with random treatment assignment, a critical but untestable assumption for valid and unbiased estimates of the indirect effects is that there should be no omitted variable that confounds indirect effects. One way to address this untestable assumption is to conduct sensitivity analysis to assess whether the inference about an indirect effect would change under varying degrees of confounding bias. We developed a sensitivity analysis technique for a latent growth curve mediation model. We compute the biasing effect of confounding on point and confidence interval estimates of the indirect effects in a structural equation modeling framework. We illustrate sensitivity plots to visualize the effects of confounding on each indirect effect and present an empirical example to illustrate the application of the sensitivity analysis. 相似文献
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Through a synthesis of test publisher norms and national longitudinal data sets, this study provides new national norms of academic growth in K–12 reading and math to help reinterpret conventional effect sizes in time units. We propose d?, a time-indexed–effect-size metric to estimate how long it would take for an “untreated” control group to reach the treatment group outcome in terms familiar to educators—years/months of schooling. It serves as a supplement to conventional effect-size metrics, such as Cohen's d, by taking into account different amounts of time needed for learning at different ages or grade levels. Through applications to Project STAR small class effects and NAEP racial achievement gaps, we demonstrate how to interpret and use d?. It is expected to provide a more developmentally appropriate context for interpreting the size of an effect, a step toward bridging the gap between educational research and practice. 相似文献
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LUAN Cui-ju SONG Guang-hua ZHENG Yao 《浙江大学学报(A卷英文版)》2006,7(10):1634-1641
INTRODUCTION The computational grid (Foster and Kesselman, 1998) combines computing, network and storage resources to support the running of large-scale ap- plications, which may be computation-intensive or communication-intensive. There are many technical challenges for deploying large-scale applications over this distributed computing environment due to the vast diversity of resources involved. Efficient and application-adaptive resource management and scheduling are challenging tasks i… 相似文献
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节奏特征对于语音的自然度有直接影响。针对普通话语音,本文比较了普通话母语者、母语为粤语的二语学习者、母语为英语的二语学习者的节奏模式。研究从含有轻声的孤立词开始,重点考察连续语流,通过11种时长指标的测量从客观上分析节奏模式。针对连续语流的研究发现,基于语速无关的或者语速归一化的时长指标,作为二语的普通话显示出与母语普通话非常接近的节奏模式;而基于未做语速归一化处理的时长指标,作为二语的普通话则向重音节拍模式的方向迁移,与说话人母语的节奏模式无关。这一结果,与孤立词情形下的结果并不一致,也违反了母语迁移效应的一般假设,但是与我们的听感基本吻合,其原因可以用二语与母语的语速差异、以及韵律结构变化带来的停延频次的差异来解释。 相似文献
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Pete Goldschmidt Kilchan Choi Felipe Martinez John Novak 《School Effectiveness & School Improvement》2013,24(3):337-357
This paper investigates whether inferences about school performance based on longitudinal models are consistent when different assessments and metrics are used as the basis for analysis. Using norm-referenced (NRT) and standards-based (SBT) assessment results from panel data of a large heterogeneous school district, we examine inferences based on vertically equated scale scores, normal curve equivalents (NCEs), and nonvertically equated scale scores. The results indicate that the effect of the metric depends upon the evaluation objective. NCEs significantly underestimate absolute individual growth, but NCEs and scale scores yield highly correlated (r >.90) school-level results based on mean initial status and growth estimates. SBT and NRT results are highly correlated for status but only moderately correlated for growth. We also find that as few as 30 students per school provide consistent results and that mobility tends to affect inferences based on status but not growth – irrespective of the assessment or metric used. 相似文献
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There are substantial racial disparities in school discipline but little agreement on how best to measure them. The choice of metric can influence conclusions about the magnitude of racial discipline disproportionality and intervention effectiveness. This article describes 2 common (risk ratio, risk difference) and 3 relatively novel (standardized effect size, raw differential representation, discipline rate) approaches to evaluating racial disproportionality, with illustrations of their strengths and weaknesses. Its concludes with a discussion of the metrics and a recommendation that researchers and policymakers consider the raw number of students of color differentially disciplined, as among the easiest to understand, the most stable, and capturing the widest range of information. Even so, no metric captures all relevant aspects of disproportionality. Accordingly, researchers and policymakers should be deliberate in their specific aims in measuring discipline disproportionality and select a combination of metrics that provides information most responsive to their goals. 相似文献
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程序设计语言是用于编写计算机程序的语言。在计算机学科研究中,无论是理论研究还是技术研究的成果,最终目标要体现在计算机软件产品的程序指令系统应能机械地、严格地按照程序指令执行,而程序设计语言的特性和编码途径会对程序的可靠性、可读性、可测试性和可维护性产生深远的影响。目前,人和计算机通信仍然必须使用人工设计的语言,即程序设计语言,而几乎所有的计算都需要程序设计语言才能完成。 相似文献