Contributions in Merlin

Future broadband wireless services will involve a range of different technologies, all with varying characteristics.These differences can influence significantly how a service is defined and deployed as well as how it is commercially offered to customers. Key technologies and services that will influence and shape the future broadband telecommunication marketbroadband telecommunication market include WiFi services WiFi services based on IEEE 802.11 standards, enhanced Universal Mobile Telecommunication System (UMTS) services, mobile grid services mobile grid services , incoming call handling services, and finally alternative approaches to broadband access such as high aerial platforms high aerial platforms. Each of these technologies and services has unique requirements in terms of deployment and management.

Continuing improvements in CPU and GPU performances as well as increasing multi-core processor and cluster-based parallelism demand for flexible and scalable parallel rendering solutions that can exploit multipipe hardware accelerated graphics. In fact, to achieve interactive visualization, scalable rendering systems are essential to cope with the rapid growth of data sets. However, parallel rendering systems are non-trivial to develop and often only application specific implementations have been proposed. The task of developing a scalable parallel rendering framework is even more difficult if it should be generic to support various types of data and visualization applications, and at the same time work efficiently on a cluster with distributed graphics cards. In this paper we introduce a novel system called Equalizer, a toolkit for scalable parallel rendering based on OpenGL which provides an application programming interface (API) to develop scalable graphics applications for a wide range of systems ranging from large distributed visualization clusters and multi-processor multipipe graphics systems to single-processor single-pipe desktop machines. We describe the system architecture, the basic API, discuss its advantages over previous approaches, present example configurations and usage scenarios as well as scalability results.

Defect prediction is an important task in the mining of software repositories, but the quality of predictions varies strongly within and across software projects. In this paper we investigate the reasons why the prediction quality is so fluctuating due to the altering nature of the bug (or defect) fixing process. Therefore, we adopt the notion of a concept drift, which denotes that the defect prediction model has become unsuitable as set of influencing features has changed – usually due to a change in the underlying bug generation process (i.e., the concept). We explore four open source projects (Eclipse, OpenOffice, Netbeans and Mozilla) and construct file-level and project-level features for each of them from their respective CVS and Bugzilla repositories. We then use this data to build defect prediction models and visualize the prediction quality along the time axis. These visualizations allow us to identify concept drifts and – as a consequence – phases of stability and instability expressed in the level of defect prediction quality. Further, we identify those project features, which are influencing the defect prediction quality using both a tree induction-algorithm and a linear regression model. Our experiments uncover that software systems are subject to considerable concept drifts in their evolution history. Specifically, we observe that the change in number of authors editing a file and the number of defects fixed by them contribute to a project’s concept drift and therefore influence the defect prediction quality. Our findings suggest that project managers using defect prediction models for decision making should be aware of the actual phase of stability or instability due to a potential concept drift.

The article discusses and analyzes data from several economic experiments in a household survey with mothers of preschool children. The researchers measured competitiveness by giving the subjects the choice between competing in a tournament or receiving a piece rate for a real effort task. The subjects also participated in lottery choices, which enabled the researchers to assess their risk preferences. The relationship between social preferences and competitiveness in the sample of mothers of preschool children was analyzed. The hypothesis that egalitarian subjects aren't as likely to self-select into competitive environments, which can produce winners and losers, was tested. A negative relationship between egalitarian choices and self-selection into competition was found.

In some past diploma thesis a PM-platform was developed for the support of the project mioBook from the research are Man | Informatics | Organization (MIO) at the Department of Informatics at the University of Zurich. The PM-platform is based on the extreme programming paradigm. This bachelor thesis works on the extension of the existing platform and reengineers the dynamic administration of roles and user privileges under the principles of Plone and Zope. The main focus here was the collaborative writing module which had enormous problems with the administration of roles and user privileges. Alongside, the PM-platform was ported on MacOSX and provided the Department of Informatics at the University of Zurich as test environment.

Web applications are being developed after XP methodology demand more comprehensive testing which are increasingly complex. These complexities have proved to increase test cost and have been error prone. Web application users demand high quality factors such as zero defect and high availability. Integrating a test automation mechanism for testing the software under development provides support for the reduction of costly test cycles and reworks. Integrating a monitoring system provides a solution to continuously availability of the web application. This thesis concentrates on development of a test center utilizing Canoo Webtest for test automation of graphical user interfaces of 360? Feedback web application. It describes test strategies and techniques that are applied in order to coverage toward required test exit criteria. Also, thesis explores methodologies that are used for the synchronization of application and test software which are already applied in the test center. Integrating a monitoring system utilizing Nagios as monitoring engine and its plugin called WebInject software provides a complete solution for high availability of the production instance of 360? Feedback application.

Current clustering techniques are able to identify arbitrarily shaped clusters in the presence of noise, but depend on carefully chosen model parameters. The choice of model parameters is difficult: it depends on the data and the clustering technique at hand, and finding good model parameters often requires time consuming human interaction. In this paper we propose CORE, a new nonparametric clustering technique that explicitly computes the local maxima of the density and represents them with cores. CORE proposes an adaptive grid and gradients to define and compute the cores of clusters. The incrementally constructed adaptive grid and the gradients make the identification of cores robust, scalable, and independent of small density fluctuations. Our experimental studies show that CORE without any carefully chosen model parameters produces better quality clustering than related techniques and is efficient for large datasets.

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