Contributions in Merlin

ENGLISH: Conventional wisdom views demographic change as a set of exogenous shocks impinging on social security, with the economy treated as a closed system. This contribution argues that demographics is nothing but the aggregate of individual decisions, which are influenced by social security. This claim is supported by both theoretical argument and empirical evidence with regard to decisions over the life cycle, ranging from educational effort, marriage, number of children, divorce, retirement, and effort to extend one's life. Distinguishing the effects of contributions and benefits of social security, these feedback relationships are shown to in the main hamper employment and growth, thus undermining the financial viability of today's social security schemes, with increasing openness of the economy (`globalization') exacerbating problems. DEUTSCH: Demographischer Wandel wird üblicherweise als ein exogener Schock auf die Sozialversicherung einer geschlossenen Volkswirtschaft aufgefasst. Der vorliegende Aufsatz wählt demgegenüber eine andere Sichtweise: Er fasst demographische Entwicklung als Ergebnis individueller Optimierungsentscheidungen auf, die von der Sozialversicherung einer Volkswirtschaft beeinflusst werden. Diese Behauptung wird durch theoretische und empirische Evidenz bezüglich des gesamten Lebenszyklus bestätigt – von der Ausbildung, über die Heirat, die Anzahl der Kinder, eine mögliche Scheidung, den Übergang in den Ruhestand und schliesslich den Versuch, ein langes Leben zu erreichen. Dabei wird durchweg zwischen den Beiträgen und den Leistungen unterschieden und gezeigt, wie diese beiden Aspekte der Sozialversicherung Beschäftigung und Wachstum beeinträchtigen können. Diese Effekte gefährden das Gleichgewicht der heutigen Sozialversicherung, wobei die Globalisierung die Gefährdung noch erhöht.

We consider a reduced form model with acquisitions and entry. There are two investors and several small non-investing firms. One investor can acquire a small firm, the other investor decides about market entry. After that all firms play an oligopoly game. We derive conditions under which increasing market concentration arises with myopic firms. We apply the framework to a Cournot model with cost synergies and a Bertrand model where acquisitions extend the product spectrum of a firm.

Wenn ein Bankangestellter «seine» Bank um Milliarden betrügen kann, wenn Investment-Banker wie wild allzu riskante Geschäfte eingehen, wenn Fabriken plötzlich riesige Kostenblöcke darstellen, liegt für Aussenstehende immer die Frage nah, wie denn ein Unternehmen so ausser Kontrolle geraten kann. Die Autoren des folgenden Beitrags legen dar, wie die interne Steuerung und Kontrolle in einem Unternehmen zu konzipieren ist, was man davon erwarten darf und worin die Ursachen von Fehlleistungen liegen.

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The Semantic Web uses a number of knowledge representation (KR) languages to represent the terminological knowledge of a domain in a structured and formally sound way. Such KRs are typically description logics (DL), which are a particular kind of knowledge representation languages. One of the underpinnings of the Semantic Web and, therefore, a strength of any such semantic architecture, is the ability to reason from data, that is, to derive new knowledge from basic facts. In other words, the information that is already known and stored in the knowledgebase is extended with the information that can be logically deduced from the ground truth. The world does, however, generally not fit into a fixed, predetermined logic system of zeroes and ones. To account for this, especially in order to deal with the uncertainty inherent in the physical world, different models of human reasoning are required. Two prominent ways to model human reasoning are similarity reasoning (aka analogical reasoning) and inductive reasoning. It has been shown in recent years that the notion of similarity plays an important role in a number of Semantic Web tasks, such as Semantic Web service matchmaking, similarity-based service discovery, and ontology alignment. With inductive reasoning, two prominent tasks that can benefit from the use of statistical induction techniques are Semantic Web service classification and (semi-) automatic semantic data annotation. This dissertation transfers these ideas to the Semantic Web. To this end, it extends the well-known RDF query language SPARQL with two novel, non-deductive reasoning extensions in order to enable similarity and inductive reasoning. To address these issues, specifically to implement the two novel reasoning variants by using SPARQL, we introduce the concept of virtual triple patterns. Virtual triples are not asserted but inferred. Hence, they do not exist in the knowledgebase, but, rather, only as a result of the similarity/inductive reasoning process. To address similarity reasoning, we present the iSPARQL (imprecise SPARQL) framework---an extension of traditional SPARQL that supports customized similarity strategies via virtual triple patterns in order to explore an RDF dataset for similar resources. For our inductive reasoning extension, we introduce our SPARQL-ML (SPARQL Machine Learning) approach to create and work with statistical induction/data mining models in traditional SPARQL. Our presented iSPARQL and SPARQL-ML frameworks are validated using five different case studies of heavily researched Semantic Web and Software Analysis tasks. For the Semantic Web, these tasks are semantic service matchmaking, service discovery, and service classification. For Software Analysis, we conduct some experiments in software evolution and bug prediction. By applying our approaches to this large number of different tasks, we hope to show the approaches' generality, ease-of-use, extensibility, and high degree of flexibility in terms of customization to the actual task.

The paper applies spatial econometric techniques to measure the impact of airport noise on the price of single-family homes in the Zurich Airport area. We exploit a large database of geo-referenced noise measurements to investigate the reaction of prices to different noise metrics. The particular institutional setting of Zurich Airport, with changing patterns of runways configurations allows to distinguish the impact of noise at different times of the day. The use of neighborhood fixedeffects is compared to the results given by a costlier modelling strategy involving a rich set of location descriptors. The paper documents the impact of airport noise on housing prices. In the base model specification the Noise Discount Index is 0.97% with typical discounts in the range of -2% to -8%. Accounting for the spatiality of the data has little effect on the results.

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