In large enterprises, asynchronous communication and messaging are gaining importance as integration solutions between applications. The concept of a message broker has been proposed as a universal mediator at the cen...
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In the context of software cost estimation, system size is widely taken as a main driver of system development effort, but other structural design properties, such as coupling, cohesion and complexity, have been sugge...
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ISBN:
(纸本)0769510434
In the context of software cost estimation, system size is widely taken as a main driver of system development effort, but other structural design properties, such as coupling, cohesion and complexity, have been suggested as additional cost factors. In this paper, using effort data from an object-oriented development project, we empirically investigate the relationship between class size and the development effort for a class, and what additional impact structural properties such as class coupling have on effort. We use Poisson regression and regression trees to build cost prediction models from size and design measures, and use these models to predict the system development effort. We also investigate a technique to combine regression trees with regression analysis, which aims at building more accurate models. The results indicate that fairly accurate predictions of class effort can be made based on simple measures of the class interface size alone; mean MREs (magnitudes of relative error) are below 30%. Effort predictions at the system level are even more accurate as, using bootstrapping, the estimated 95% confidence interval for MREs is 3%-23%, but more sophisticated coupling and cohesion measures do not help to improve these predictions to a degree that would be practically significant. However, the use of hybrid models, combining Poisson regression and CART (classification and regression trees) clearly improves the accuracy of the models as compared to using Poisson regression alone.
We present a recently developed technology for the stacking of optical waveguides using hybrid inorganic-organic polymers (ORMOCER(R)s). Among advantages with respect to the use of low-cost conventional processing met...
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We present a recently developed technology for the stacking of optical waveguides using hybrid inorganic-organic polymers (ORMOCER(R)s). Among advantages with respect to the use of low-cost conventional processing methods (e.g. photopatterning, spin coating), this material system offers high thermal stability and low optical attenuation at telecom wavelengths. The stacking process faces several fundamental problems, such as broadening of the structures during UV patterning or the appearance of index inhomogeneities generated by diffusion effects. In addition, the nonlinear index change of the polymer materials during polymerization has to be considered carefully to ensure defined index distributions in all layers. A solution meeting these requirements, substantially reverting to standard processes, is presented. The key points, an UV absorber method and a combined UV and thermal curing, are investigated in detail. As an example, the realization and test of an optical fanout element composed of four waveguide layers, each with 8 channels of equal path lengths, is shown.
The inspection of early life-cycle artifacts such as requirement documents promises great benefits. However, research demonstrates that the inspection process is complex and expensive and that tool support would be hi...
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ISBN:
(纸本)076951426X
The inspection of early life-cycle artifacts such as requirement documents promises great benefits. However, research demonstrates that the inspection process is complex and expensive and that tool support would be highly desirable. Existing inspection tools focus largely on the inspection of source code. We have therefore devised groupware support for inspecting requirements. Based on our experience with adopting a group support system (GSS) for requirements negotiation, we decided to tailor this commercial GSS to support inspection of requirements. The paper discusses our concept of a Groupware-supported Requirements Inspection Process (GRIP) and shows that tailoring a COTS GSS works well to automate this process.
The recently completed ALTSET project was part of the European Commission's Standards, Measurement and Testing programme. Its objective was the development of European standard test procedures for the determinatio...
Standard groupware products do not fulfill the specific requirements of various application areas, due to technical restrictions, lack of flexibility or non-availability of adapted interfaces. In view of this situatio...
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Public transportation properties as well as the supply industry are often organized by separate lots/subsystems such as tracks, fixed facilities, train controls, rolling stock etc. This results in optimized subsystems...
Public transportation properties as well as the supply industry are often organized by separate lots/subsystems such as tracks, fixed facilities, train controls, rolling stock etc. This results in optimized subsystems but leaves often a potential for the optimization of the total transportation system. In order to optimize the overall quality objectives of the very complex transportation systems, the interface management and system integration process need to go beyond the detailed requirement specification of functionalities. RAMS and Life Cycle Cost requirements need to be defined and optimized already at the systems level and broken down into subsystem requirements as a continuous design activity throughout the system life cycle. Actual open issues, good practice example, a process proposal and future aspects are discussed in this paper. Particular consideration is given to the question of top down/bottom up safety engineering.
Standard groupware products do not fulfill the specific requirements of various application areas, due to technical restrictions, lack of flexibility or non-availability of adapted interfaces. In view of this situatio...
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Standard groupware products do not fulfill the specific requirements of various application areas, due to technical restrictions, lack of flexibility or non-availability of adapted interfaces. In view of this situation, development of groupware products for specialized application areas will continue to be necessary. Our approach is to support this kind of software development project by providing: a reference architecture for groupware applications as a guideline for software developers; reusable components and services; and design and architecture patterns. This paper presents a view concept for software architectures, a global reference architecture for groupware applications and an example from the application field of Web-publishing.
Delivering a software product on time, within budget, and to an agreed level of quality is a critical concern for many software organizations. Underestimating software costs can have detrimental effects on the quality...
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Delivering a software product on time, within budget, and to an agreed level of quality is a critical concern for many software organizations. Underestimating software costs can have detrimental effects on the quality of the delivered software and thus on a company's business reputation and competitiveness. On the other hand, overestimation of software cost can result in missed opportunities to funds in other projects. In response to industry demand, a myriad of estimation techniques has been proposed during the last three decades. In order to assess the suitability of a technique from a diverse selection, its performance and relative merits must be compared. The current study replicates a comprehensive comparison of common estimation techniques within different organizational contexts, using data from the European Space Agency. Our study is motivated by the challenge to assess the feasibility of using multi-organization data to build cost models and the benefits gained from company-specific data collection. Using the European Space Agency data set, we investigated a yet unexplored application domain, including military and space projects. The results showed that traditional techniques, namely, ordinary least-squares regression and analysis of variance outperformed analogy-based estimation and regression trees. Consistent with the results of the replicated study no significant difference was found in accuracy between estimates derived from company-specific data and estimates derived from multi-organizational data.
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