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题名:
模糊逻辑的采用软件开发工作量估算
作者: MUHAMMADWASIFNISAR
答辩日期: 2009-01-16
授予单位: 中国科学院软件研究所
授予地点: 软件研究所
学位: 博士
关键词: 工作量估算 ; 模糊逻辑
其他题名: Software Development Effort Estimation using Fuzzy Logic
摘要: 软件估算是有半个世纪发展历史的计算机科学领域的一个巨大挑战,因为软件估算涉及到软件项目的成本和计划。开发人员需要能够获得基于他们自己的程序得到的包含了工作量估算的实践。软件成本估算主要估算开发软件系统所需的工作量、时间、人力资源等。一种有效的方式是在项目早期确定成本时估算工作量。软件成本主要依据项目的需求规格说明书来确定。目前,实施可靠、准确的成本估算仍是软件工程领域的一个挑战。 在项目早期阶段,许多项目属性尚未确定。此时的软件估算通常是不准确的,估算 的准确程度取决于用于估算的可靠且可用的信息的数量。在后续的项目分析和设计阶段,对项目的了解更加深入,估算不确定性减少,估算准确性提高。大部分估算模型未考虑这种不确定性,只是得到了确定的估算结果。这些模型需要改进,以得到估计范围和估算结果的发生概率。 新的方法(如:模糊逻辑)可能提供了软件工作量估算的替代方案。软件开发总是可以用一组具有一定程度模糊性的参数来表征。这就需要在模型中引入一定程度的不确定性,以使模型更接近实际。模糊逻辑在这方面很合适。应用模糊逻辑可以解决目前工作量估算模型存在的许多问题。而且,模糊逻辑已经与算法的和非算法的工作量估算模型结合,用于解决固有不确定性问题。 本文提出一种基于模糊逻辑规模的软件开发工作量估算方法。软件规模不是一个单个数字,可以看作是一个三角模糊数(triangular fuzzy number, TFN)。应用本文方法,可以通过改变约束条件对任意常数中的工作量估算结果进行优化。基于对本文方法中模糊权重的平均方差解释%(Variance Accounted For, VAF%) , 提出了一种最优化算法。应用COCOMO 公开数据集进行了验证实验。与实际工作量估算的比较结果表明,基于偏差系数,本文提出的模型提供了较好的估算结果。 最后,提出了一种改进的基于模糊案例的推理(Fuzzy Case-Based Reasoning , FCBR)方法,该方法集成了agent 技术,可以从多个组织的分布式数据库中找到相似项目。基于该方法,可以从分布式预定义的项目成本数据库中收集软件成本数据,进而建立软件成本估算模型。该模型应用FCBR 方法,在不同软件组织的历史软件项目度量数据中找到类似项目。
英文摘要: Software estimation has been identified as one of the great challenges for half-century-old computer science because it allows for considerable financial and strategic planning. Developers need to be able to achieve practices containing effort estimation based on their own programs. Software cost estimation refers to the predictions of the likely amount of effort, time, and staffing levels required to build a software system. A very helpful form of effort prediction is the one made at an early stage during a project, when the costing of the project is proposed for approval. This project costing is derived primarily from requirements specifications documents. The need for reliable and accurate cost predictions in software engineering is an ongoing challenge. At the initial stage of a project, there is high uncertainty about these project attributes. The estimate produced at this stage is inevitably inaccurate, as the accuracy depends highly on the amount of reliable information available to the estimator. As we learn more about the project during analysis and later design stages, the uncertainties are reduced and more accurate estimates can be made. Most models produce exact results without regard to this uncertainty. They need to be enhanced to produce a range of estimates and their probabilities. New paradigms as fuzzy logic may offer an alternative for software effort estimation. The development of software has always been characterized by parameters that possess certain level of fuzziness. This requires that some degree of uncertainty be introduced in the models, in order to make the models realistic. Fuzzy logic fares well in this area. Many of the problems of the existing effort estimation models can be solved by incorporating fuzzy logic. Besides, fuzzy logic had been combined with algorithmic, non-algorithmic effort estimation models as well as a combination of them to deal with the inherent uncertainty issues. This work proposed a method for software development effort estimation based on fuzzy logic sizing. Rather than a single number, the software size is regarded as a triangular fuzzy number (TFN). We can optimize the estimated effort for any application by varying arbitrary constants for the proposed method. An optimization algorithm is proposed based on the Variance Accounted For (VAF %) for the weights of fuzzy estimates of the proposed method. validation experiment was carried out on the COCOMO public database. Comparison to the actual effort estimates shows our model provides relatively good estimates based on Coefficient of Variation (C.V %). Last part proposed an improved Fuzzy Case-Based Reasoning (FCBR) approach integrated with agent technology to retrieve similar projects from multi-organizational distributed datasets. This work explores the possibility of building a software cost estimation model by collecting software cost data from distributed predefined project cost databases. The model applying FCBR method to find similar projects in historical data derived from measured software projects developed by different organizations.
语种: 中文
内容类型: 学位论文
URI标识: http://ir.iscas.ac.cn/handle/311060/5864
Appears in Collections:基础软件国家工程研究中心_学位论文

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Recommended Citation:
MUHAMMADWASIFNISAR. 模糊逻辑的采用软件开发工作量估算[D]. 软件研究所. 中国科学院软件研究所. 2009-01-16.
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