This paper investigates two essential questions related to data-driven, software cost modeling: (1) What modeling techniques are likely to yield more accurate results when using typical software development cost data?...
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This paper investigates two essential questions related to data-driven, software cost modeling: (1) What modeling techniques are likely to yield more accurate results when using typical software development cost data? and (2) What are the benefits and drawbacks of using organization-specific data as compared to multi-organization databases? The former question is important in guiding software cost analysts in their choice of the right type of modeling technique, if at all possible. In order to address this issue, we assess and compare a selection of common cost modeling techniques fulfilling a number of important criteria using a large multi-organizational database in the business application domain. Namely, these are: ordinary least squares regression, stepwise ANOVA, CART, and analogy. The latter question is important in order to assess the feasibility of using multi-organization cost databases to build cost models and the benefits gained from local, company-specific data collection and modeling. As a large subset of the data in the multi-company database came from one organization, we were able to investigate this issue by comparing organization-specific models with models based on multi-organization data. Results show that the performances of the modeling techniques considered were not significantly different, with the exception of the analogy-based models which appear to be less accurate. Surprisingly, when using standard cost factors (e.g., COCOMO-like factors, Function Points), organization specific models did not yield better results than generic, multi-organization models.
We present the characteristics of component-based softwareengineering and derive the requirements for a corresponding development process. Based on this, we propose changes and extensions for the V-Modell, the German...
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Repetitive, or multipass, processes are a class of 2D systems of both practical and algorithmic/theoretical interest whose dynamics cannot be analysed or controlled using standard (1D) systems theory. Recently it has ...
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Building softwaresystems out of pre-fabricated components is a very attractive vision. Distributed Component Platforms (DCP) and their visual development environments bring this vision closer to reality than ever. At...
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(纸本)9783540665380
Building softwaresystems out of pre-fabricated components is a very attractive vision. Distributed Component Platforms (DCP) and their visual development environments bring this vision closer to reality than ever. At the same time, some experiences with component libraries warn us about potential problems that arise in case of software system families or systems that evolve over many years of changes. Indeed, implementation level components, when affected by many independent changes, tend to grow in both size and number, impeding reuse. In this paper, we analyze in detail this effect and propose a program construction environment, based on generative techniques, to help in customization and evolution of component-based systems. This solution allows us to reap benefits of DCPs during runtime and, at the same time, keep components under control during system construction and evolution. In the paper, we describe such a construction environment for component-based systems that we built with a commercial generator and illustrate its features with examples from our domain engineering project. The main lesson learnt from our project is that generative techniques can extend the strengths of the component-based approach in two important ways: Firstly, generative techniques automate routine component customization and composition tasks and allow developers work more productively, at a higher abstraction level. Secondly, as custom components with required properties are generated on demand, we do not need to store and manage multiple versions of components, components do not overly grow in size, helping developers keep the complexity of an evolving system under control.
Viewing software structure as a composition of components is helpful to enable software maintenance to be carried out at a higher level than language statements, as well as to improve software maintenance efficiency a...
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Viewing software structure as a composition of components is helpful to enable software maintenance to be carried out at a higher level than language statements, as well as to improve software maintenance efficiency and quality, and to increase the reuse rate of existing software components in maintenance. In this paper, types of software maintenance are classified and scopes of software components in component-based software maintenance are analyzed. A new kind of built-in test (BIT) components for maintainable software is developed Based on this, a test/maintenance mode of maintainable software is proposed. Implementation approaches of the BIT components for software maintenance are developed. Applications of the BIT components in enhancing software maintainability in reengineering legacy systems for maintainability, and in ensuring run-time consistency are described.
A novel hybrid compression scheme for videoconferencing and videotelephony applications at very low bit rates (i.e., 32 Kbits/s) is presented. The human face is the most important region within a frame and should be c...
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Technical reviews are a cost effective method commonly used to detect software defects early. To exploit their full potential, it is necessary to collect measurement data to constantly monitor and improve the implemen...
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Technical reviews are a cost effective method commonly used to detect software defects early. To exploit their full potential, it is necessary to collect measurement data to constantly monitor and improve the implemented review procedure. This paper postulates a model of the factors that affect the number of defects detected during a technical review, and tests the model empirically using data from a large software development organization. The data set comes from more than 300 specification, design, and code reviews that were performed at Lucent's Product Realization Center for Optical Networking (PRC-ON) in Nuernberg, Germany. Since development projects within PRC-ON usually spend between 12% and 18% of the total development effort on reviews, it is essential to understand the relationships among the factors that determine review success. One major finding of this study is that the number of detected defects is primarily determined by the preparation effort of reviewers rather than the size of the reviewed artifact. In addition, the size of the reviewed artifact has only limited influence on review effort. Furthermore, we identified consistent ceiling effects in the relationship between size and effort with the number of defects detected. These results suggest that managers at PRC-ON must consider adequate preparation effort in their review planning to ensure high quality artifacts as well as a mature review process.
Modern high-performance embedded systems face many challenges. systems must function in rapidly changing environments. Power/size constraints limit hardware size, while extreme performance requirements demand algorith...
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Modern high-performance embedded systems face many challenges. systems must function in rapidly changing environments. Power/size constraints limit hardware size, while extreme performance requirements demand algorithm specific architectures. Hardware architectures must structurally adapt to achieve high performance with changing algorithms. Reconfigurable computing devices offer the promise of architectures that change in response to the changing environment. The primary difficulty in this approach lies in system design. A model-integrated approach is used in the design capture and synthesis of these systems. The target systems are built on a heterogeneous computing platform including configurable hardware, ASIC and general purpose processors and DSPs. This project is a DARPA Adaptive Computing systems funded effort, involving close cooperation with US ARMY/AMICOM.
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