The intensifying need for scalable software has motivated modular development and using systems distributed over networks to implement large-scale applications. In Service-oriented Computing,... Show moreThe intensifying need for scalable software has motivated modular development and using systems distributed over networks to implement large-scale applications. In Service-oriented Computing, distributed services are composed to provide large-scale services with a specific functionality. In this way, reusability of existing services can be increased. However, due to the heterogeneity of distributed software systems, software composition is not easy and requires additional mechanisms to impose some form of a coordination on a distributed software system. Besides functional correctness, a composed service must satisfy various quantitative requirements for its clients, which are generically called its quality of service (QoS). Particularly, it is tricky to obtain the overall QoS of a composed service even if the QoS information of its constituent distributed services is given. In this thesis, we propose Stochastic Reo to specify software composition with QoS aspects and its compositional semantic models. They are also used as intermediate models to generate their corresponding stochastic models for practical analysis. Based on this, we have implemented the tool Reo2MC. Using Reo2MC, we have modeled and analyzed an industrial software, the ASK system. Its analysis results provided the best cost-effective resource utilization and some suggestions to improve the performance of the system. Show less
Many decisions in the legal system are based on eyewitness evidence. It seems to be a matter of common sense that the level of confidence expressed by a witness can be used as a diagnostic tool to... Show moreMany decisions in the legal system are based on eyewitness evidence. It seems to be a matter of common sense that the level of confidence expressed by a witness can be used as a diagnostic tool to discriminate between accurate and inaccurate memories. Contrary to this general belief, the bulk of empirical evidence collected in laboratory and field experiments over the past 25 years indicates that the relationship between confidence and accuracy is far from perfect. The central focus of this dissertation is on the accuracy of eyewitness memory, and especially on the relationship between accuracy and confidence (i.e., the subjective judgment of accuracy). To enhance the ecological validity of the laboratory studies, we used a method that allowed us to determine accuracy and confidence scores for the recall of details of complex naturalistic events. The first three chapters are experiments from the laboratory testing the effect of repeated retrieval, retention interval and repeated misleading questioning. The fourth chapter is a case study in which real live witnesses of a robbery on a supermarket were interviewed. Our findings show a clear and consistent relationship between confidence judgements and the actual accuracy of memories. With some caution, confidence may be used as a partial indicator of accuracy, especially during the early stages of an investigation. Unfortunately, however, there always remain incorrect items that are given the maximum confidence score. That is the reason why no single witness statement can be accepted as certainly correct, based on confidence alone. Show less
