Contributions in Merlin

Observing the evolution of very large software systems is difficult because of the sheer amount of information that needs to be analyzed and because the changes performed in the system are at a very low granularity level. In recent approaches software metrics have been used to compute condensed graphical visualizations of these data also reflecting metrics. However, most techniques concentrate on visualizing data of one particular release providing only insufficient support for visualizing data of several selected releases. In this paper we present the RelVis visualization approach that provides integrated condensed graphical views on source code and release history data of up to n releases of a software system. Measurements of metrics of n releases are composed to views that facilitate spectators to spot trends of metrics of source code entities and relationships. Critical trends are highlighted: This allows the user to direct perfective maintenance activities to source code entities involved. The paper provides needed background information and evaluation of the approach with a large open source software project.

Language definition is always an important topic in the field of computer science. For textual specification and programming languages, there are already lots of mature methods of language definition. However, for visual specification languages, especially the so called wide spectrum graphical modeling languages, the existing solutions are far from satisfactory. ADORA is a modelling technique for requirements and software architecture that is being developed in the Requirement Engineering Research Group, University of Zurich. The acronym stands for Analysis and Description of Requirements and Architecture. ADORA and UML are typical examples of wide spectrum graphical modeling languages. In this dissertation, we propose a new method of defining visual specification languages, which shall overcome the drawbacks of the existing definition methods. The ADORA Language, which is used to model system requirements and software architecture, is selected as a vehicle for demonstrating our method. The following four aspects of language definition are particularly addressed: · Syntax and static semantics definition A text-based technique is given for the syntax and static semantics definition. We exploit the fact that in a visual specification language, most syntactic features are independent of the layout of the graph. So we map the graphical elements to textual ones and define the context-free syntax of this textual language in EBNF. Using our mapping, this grammar also defines the syntax of the graphical language. Simple spatial and context-sensitive constraints are then added by attributing the context-free grammar. Finally, for handling complex structural and dynamic information in the syntax, most of which is also called static semantics in the literature, we give a set of operational rules that work on the attributed EBNF. We also extend this set of operational rules to specify an advanced feature of \textscAdora, which supports the description of partial and evolutionary specifications. · Dynamic semantics definition We propose a strategy of dynamic semantics definition for ADORA: instead of defining a formal semantics for the whole language at one time, which can be too complex to be understood and used, we define semantics first only for each simple sublanguage. Then an integration semantics, which specifies the interrelations and constraints among the sublanguages, is defined to keep the language self-consistent. Examples on the integration semantics are given to show how our strategy works. Our solution is also valid for other wide spectrum graphical modeling languages. · Refinement calculus We define a formal refinement calculus for the structural view, behavioral view and user view of the ADORA language. This ensures that evolutionary specifications are written in a controlled and systematic way, while the consistency and integrity checking during the system refinement can be mechanically carried out by a tool based on our formal definition. · The reciprocal influences between the language definition and language design During the process of formal definition of ADORA, we also continue to design the language (e.g. the extension of ADORA for supporting partial and evolutionary specification). We conclude that language design and language definition are not two independent tasks. The study of the reciprocal influences between these two tasks improves the quality of the language definition. A set of principles derived from our development of ADORA is presented. Our methods can also be used to define UML or any other wide-spectrum modeling languages in the near future. Compared with the existing works on the graphical modeling language definition, our language definition is more understandable, easier to apply and practically more useful. The achieved results on the refinement calculus, syntax and semantics definition are also valuable for the similar research. At the end of this dissertation, limitations, open questions and future works are discussed.

In the past decade, Switzerland has experienced a large increase in the number of individuals going into early retirement. This paper examines the determinants of such early retirement using data from the newly implemented social-security module of the 2002 Swiss Labor Force Survey. In the sixteen-month period from January 2001 to April 2002, more than 36,000 older individuals, representing 8% of all workers within nine years of legal retirement age, became early retirees. One of the most important determinants of early retirement is the wage rate, yet its effect is not linear: both high and low wages reduce the probability. Other factors that play an important role include partner's employment status, education, industry, occupation, and coverage in the three social-security pillars. A major finding of this study is that about 30% of all early retirees continue working after retirement - and mostly for the same employer.

We review how technological advances and changes in regulation may shape the (future) geographical scope of banking. We first review how both physical distance and the presence of borders currently affect bank lending conditions (loan pricing and credit availability) and market presence (branching and servicing). Next we discuss how technology and regulation have altered this impact and analyse the current state of the European banking sector. We discuss both theoretical contributions and empirical work and highlight open questions along the way. We draw three main lessons from the current theoretical and empirical literature: (i) bank lending to small businesses in Europe may be characterized both by (local) spatial pricing and resilient (regional and/or national) market segmentation; (ii) because of informational asymmetries in the retail market, bank mergers and acquisitions seem the optimal route of entering another market, long before cross-border servicing or direct entry are economically feasible; and (iii) current technological and regulatory developments may, to a large extent, remain impotent in further dismantling the various residual but mutually reinforcing frictions in the retail banking markets in Europe. We conclude the paper by offering pertinent policy recommendations based on these three lessons.

The semantic web presents the vision of a distributed, dynamically growing knowledge base founded on formal logic. Common users, however, seem to have problems even with the simplest Boolean expression. As queries from web search engines show, the great majority of users simply do not use Boolean expressions. So how can we help users to query a web of logic that they do not seem to understand? We address this problem by presenting a natural language front-end to semantic web querying. The front-end allows formulating queries in Attempto Controlled English (ACE), a subset of natural English. Each ACE query is translated into a discourse representation structure – a variant of the language of first-order logic – that is then translated into the semantic web querying language PQL. As examples show, our approach offers great potential for bridging the gap between the semantic web and its real-world users, since it allows users to query the semantic web without having to learn an unfamiliar formal language.

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This paper purports to develop a simple microeconomic model designed to shed light on behavioral change induced by improved information about smoking risks. It predicts the conditions in which improved information indeed increases the demand for cigarettes. After recalling the economic rationale of an anti-tobacco policy, the article points out a few startling implications of improved information about the risks of smoking.

Life critical applications in hospital environments have got special requirements concerning IT support: a real-time cooperation is necessary to ensure a continuous workflow. This article describes the prototypic realization of the EMIKA project, a real-time controlled mobile information system for clinical applications. The EMIKA architecture is comprised of three layers: first of all, the Communication Layer provides wireless device interaction. Secondly, the Middleware Layer establishes a common service platform for automated service provision and access. Finally, the Application Layer implements a multi-agent-system for the real-time coordination needed for a self-organizing patient logistics environment.

We show that for international economies with two countries, in which agents have additively separable utility functions, the existence of sunspot equilibria is equivalent to the occurrence of the transfer paradox. This equivalence enables us to provide some new insights on the relation of the existence of sunspot equilibria and the multiplicity of spot market equilibria.