Description logics (DLs) are used to represent knowledge of an application domain and provide standard reasoning services to infer consequences of this knowledge. However, classical DLs are not suited to represent vagueness in the description of the knowledge. We consider a combination of DLs and Fuzzy Logics to address this task. In particular, we consider the t-norm-based semantics for fuzzy DLs introduced by Hájek in 2005. Since then, many tableau algorithms have been developed for reasoning in fuzzy DLs. Another popular approach is to reduce fuzzy ontologies to classical ones and use existing highly optimized classical reasoners to deal with them. However, a systematic study of the computational complexity of the different reasoning problems is so far missing from the literature on fuzzy DLs. Recently, some of the developed tableau algorithms have been shown to be incorrect in the presence of general concept inclusion axioms (GCIs). In some fuzzy DLs, reasoning with GCIs has even turned out to be undecidable. This work provides a rigorous analysis of the boundary between decidable and undecidable reasoning problems in t-norm-based fuzzy DLs, in particular for GCIs. Existing undecidability proofs are extended to cover large classes of fuzzy DLs, and decidability is shown for most of the remaining logics considered here. Additionally, the computational complexity of reasoning in fuzzy DLs with semantics based on finite lattices is analyzed. For most decidability results, tight complexity bounds can be derived.

Description logics knowledge bases are a popular approach to represent terminological and assertional knowledge suitable for computers to work with. Despite that, the practicality of description logics is impaired by the difficulties one has to overcome to construct such knowledge bases. Previous work has addressed this issue by providing methods to learn valid terminological knowledge from data, making use of ideas from formal concept analysis. A basic assumption here is that the data is free of errors, an assumption that can in general not be made for practical applications. This thesis presents extensions of these results that allow to handle errors in the data. For this, knowledge that is "almost valid" in the data is retrieved, where the notion of "almost valid" is formalized using the notion of confidence from data mining. This thesis presents two algorithms which achieve this retrieval. The first algorithm just extracts all almost valid knowledge from the data, while the second algorithm utilizes expert interaction to distinguish errors from rare but valid counterexamples.

Ontology-based data access (OBDA) augments classical query answering in databases by including domain knowledge provided by an ontology. An ontology captures the terminology of an application domain and describes domain knowledge in a machine-processable way. Formal ontology languages additionally provide semantics to these specifications. Systems for OBDA thus may apply logical reasoning to answer queries; they use the ontological knowledge to infer new information, which is only implicitly given in the data. Moreover, they usually employ the open-world assumption, which means that knowledge not stated explicitly in the data or inferred is neither assumed to be true nor false. Classical OBDA regards the knowledge however only w.r.t. a single moment, which means that information about time is not used for reasoning and hence lost; in particular, the queries generally cannot express temporal aspects. We investigate temporal query languages that allow to access temporal data through classical ontologies. In particular, we study the computational complexity of temporal query answering regarding ontologies written in lightweight description logics, which are known to allow for efficient reasoning in the atemporal setting and are successfully applied in practice. Furthermore, we present a so-called rewritability result for ontology-based temporal query answering, which suggests ways for implementation. Our results may thus guide the choice of a query language for temporal OBDA in data-intensive applications that require fast processing, such as context recognition.

Building and mantaining large-scale ontologies is an error-prone task. It is thus not uncommon to find unwanted or unexpected consequences that follow implicitely from the restrictions in the ontology. To understand and correct these consequences, it is helpful to find the specific portions of the ontology that are responsible for them. Axiom-pinpointing is the task of finding minimal subontologies that entail a given consequence, also called MinAs. In this work we look at the task of computing all the MinAs by means of modified decision procedures. We first show that tableaux- and automata-based decision procedures can be transformed into pinpointing algorithms that output a (compact) representation of the set of all MinAs. We then explore the complexity of the problem.

Büchi, Elgot and Trakhtenbrot provided a seminal connection between monadic second-order logic and finite automata for both finite and infinite words. This BET- Theorem has been extended by Lautemann, Schwentick and Thérien to context-free languages by introducing a monadic second-order logic with an additional existentially quantified second-order variable. This new variable models the stack of pushdown au- tomata. A fundamental study by Cohen and Gold extended the context-free languages to infinite words. Our first main result is a second-order logic in the sense of Lautemann, Schwentick and Thérien with the same expressive power as ω-context-free languages. For our argument, we investigate Greibach normal forms of ω-context-free grammars as well as a new type of Büchi pushdown automata, the simple pushdown automata. Simple pushdown automata do not use e-transitions and can change the stack only by at most one symbol. We show that simple pushdown automata of infinite words suffice to accept all ω-context-free languages. This enables us to use Büchi-type results recently developed for infinite nested words. In weighted automata theory, many classical results on formal languages have been extended into a quantitative setting. Weighted context-free languages of finite words trace back already to Chomsky and Schützenberger. Their work has been extended to infinite words by Ésik and Kuich. As in the theory of formal grammars, these weighted ω-context-free languages, or ω-algebraic series, can be represented as solutions of mixed ω-algebraic systems of equations and by weighted ω-pushdown automata. In our second main result, we show that (mixed) ω-algebraic systems can be trans- formed into Greibach normal form. We then investigate simple pushdown automata in the weighted setting. Here, we give our third main result. We prove that weighted simple pushdown automata of finite words recognize all weighted context-free languages, i.e., generate all algebraic series. Then, we show that weighted simple ω-pushdown automata generate all ω-algebraic series. This latter result uses the former result together with the Greibach normal form that we developed for ω-algebraic systems. As a fourth main result, we prove that for weighted simple ω-pushdown automata, Büchi-acceptance and Muller-acceptance are expressively equivalent. In our fifth main result, we derive a Nivat-like theorem for weighted simple ω- pushdown automata. This theorem states that the behaviors of our automata are precisely the projections of very simple ω-series restricted to ω-context-free languages. The last result, our sixth main result, is a weighted logic with the same expressive power as weighted simple ω-pushdown automata. To prove the equivalence, we use a similar result for weighted nested ω-word automata and apply our present result of expressive equivalence of Muller and Büchi acceptance.

Great challenges often require the combined strength of various actors. Especially in areas that are shaped by fast technological development such as the application of additive manufacturing (AM) in life sciences, the interplay of different fields of expertise, including experts from industry, academia and government, is needed. While the collaboration of diverse actors can constitute a vast potential for innovations, it also entails a major challenge to negotiate among diverse individual interest, backgrounds, beliefs, and value systems. One field of research that can help to understand the consequences of such differences in the interests and beliefs in organizational settings is the institutional logics perspective. Institutional logics account for broader institutional value systems that guide actors’ cognition and actions. When organizations embody multiple logics, scholars speak of logic multiplicity. However, the consequences for organizational functioning that arise from logic multiplicity are still discussed among scholars, ranging from an enhanced innovativeness, to an increased conflict potential and organizational dismiss. In order to better understand logic interaction and its implications for organizational functioning, an embedded-case study was conducted. The embedded-case study focused on AddLife at Uppsala University, a competence center in its early phases of formation which is concerned with the advancement of applications of AM in life sciences. Based on semi-structured interviews and documentational data, three different logics were captured for three main stakeholder groups in AddLife. Further, the interaction of these logics during the early phases of competence center formation was analyzed, corroborating the role of logic compatibility (whether logics imply consistent goals). This study’s findings suggest that common goals have been found in AddLife, but some differences regarding the different logics’ implied goals remain, stressing the role of active mediation. Further, the study suggests that building strong intra-organizational ties is pivotal during the early phases of competence center formation, proposing a framework that encompasses three main approaches to build such ties. The first approach is to create a sense of community, including to reinforce synergies, to ensure engagement, and to connect projects. The second approach is to establish an open communication flow which comprises to clarify roles, to encourage asking questions, and to match expectations. Finally, the third approach is to organize personal meetings in order to establish relationships in the first place and to enable discussions.

Syfte: Syftet med studien är att beskriva och förstå hur de sportsliga och ekonomiskalogikerna tar form, samt jämföra hur spänningen påverkar investeringsbeslut i svenska elitfotbollsklubbar.Metod: Studien har en kvalitativ ansats och genomfördes med hjälp av semistrukturerade intervjuer med respondenter från tre elitfotbollsklubbar i Allsvenskan och Superettan. Datainsamlades även in från litteratur och vetenskapliga artiklar.Teori: Den teoretiska referensramen utgörs av teorier om institutionella logiker, spänningen mellan logikerna i fotbollsklubbar och vilka sportsliga och ekonomiska förutsättningar somsvenska elitfotbollsklubbar står inför.Empiri: Studien innehåller intervjuer med fem respondenter från tre svenskaelitfotbollsklubbar. Två fotbollsklubbar från Allsvenskan samt en fotbollsklubb frånSuperettan. Respondenterna har haft befattningen ekonomichef, sportchef ellerstyrelsemedlem.Slutsats: Fotbollsklubbar är komplexa organisationer där verksamheten är en ideell föreningmen bedrivs som ett företag. Vid investeringar uppstår en spänning mellan sportslig ochekonomisk logik. Logikerna är situationsbaserade och den logik som prioriteras skiftarberoende på den sportsliga och ekonomiska situation som fotbollsklubbarna befinner sig i.Trots att det alltid är en balansgång mellan logikerna prioriteras ofta den ekonomiska logiken på grund utav fotbollsklubbarnas ekonomiska historia. Det är vanligt att arbeta medsin ungdomsakademi, eftersom att det är både ekonomiskt försvarbart och kan genereraintäkter vid en möjlig spelarförsäljning i framtiden.

Small businesses are an important part of innovation, competitiveness and economic development. Support systems such as business incubators have emerged with the purpose of helping these startups develop. The startups which are in focus in this thesis operate in different industries, in technology-based industries where commercialization and growth is in focus, to creative industries which focus on developing individual talent and creativity. The characteristics and core of the businesses differ, giving them different business logics by which the startups operate. The business logic leads the startups to face different challenges, which the thesis considers to regard liabilities of smallness, liabilities of newness and liabilities of uniqueness as well as organizing.  These variations give the startups differences in how they operate and hence, also a need for different types of support given by business incubators. Business incubator support is in the thesis categorized into three components of Networks, Infrastructure and Business Services, as suggested in a triad model of Carvalho & Galina (2015). As varying business logics makes a difference on what type of value startups produce, it is important to study the relationship between these logics and the support provided by an incubator. It is important in order to understand how incubators can adapt their support more effectively to help entrepreneurs overcome their challenges.  The thesis purpose is to broaden the understanding of how business logics and challenges of startups adhere to the industry they are in, and how the support given by business incubators can help the businesses to overcome challenges associated with these business logics. The research design was qualitative, and data was collected by performing six semi-structured interviews with entrepreneurs within creative and technology-based industries, enrolled at business incubators with these specializations.  The study results in a proposed model, giving extension to the original triad model by Carvalho & Galina (2015). In the proposed model, new dimensions of the support system as well as the nature of the startups’ business logics, and challenges are addressed. The proposed model and the study’s results may act as a guiding framework for future research in the field, aiming to gain a better understanding of the reality of startups with different business logics.

The study of nonmonotonic logics is one mayor field of Artificial Intelligence (AI). The reason why such kind of formalisms are so attractive to model human reasoning is that they allow to withdraw former conclusion. At the end of the 1980s the novel idea of using argumentation to model nonmonotonic reasoning emerged in AI. Nowadays argumentation theory is a vibrant research area in AI, covering aspects of knowledge representation, multi-agent systems, and also philosophical questions. Phan Minh Dung’s abstract argumentation frameworks (AFs) play a dominant role in the field of argumentation. In AFs arguments and attacks between them are treated as primitives, i.e. the internal structure of arguments is not considered. The major focus is on resolving conflicts. To this end a variety of semantics have been defined, each of them specifying acceptable sets of arguments, so-called extensions, in a particular way. Although, Dung-style AFs are among the simplest argumentation systems one can think of, this approach is still powerful. It can be seen as a general theory capturing several nonmonotonic formalisms as well as a tool for solving well-known problems as the stable-marriage problem. This thesis is mainly concerned with the investigation of metalogical properties of Dung’s abstract theory. In particular, we provide cardinality, monotonicity and splitting results as well as characterization theorems for equivalence notions. The established results have theoretical and practical gains. On the one hand, they yield deeper theoretical insights into how this nonmonotonic theory works, and on the other the obtained results can be used to refine existing algorithms or even give rise to new computational procedures. A further main part is the study of problems regarding dynamic aspects of abstract argumentation. Most noteworthy we solve the so-called enforcing and the more general minimal change problem for a huge number of semantics.

The point of departure for this study is Michael Lipsky’s description and problematization of street-level bureaucrats’ discretion. Street-level bureaucrats, such as teachers, have a possibility to influence the implementation of policy at the point of delivery to citizens.This can create a problem within the democratic policy process as policy does not materialize in the way that politicians intended. I used a qualitative research design and interviewed ten teachers in upper secondary schools about their exercise of authority, in order to investigate a factor that may lead to policy-making: logics of action. I claim that logics of action are suitable tools for analyzing and discussing the policy-making that street-level bureaucrats perform in the democratic policy process. The main purpose of this study is to contribute to such a discussion. A second purpose is to elucidate logics of action as a type of factors that guides teachers’ exercise of authority, but which has not been noticed to any great extent in previous research. I investigated which logics of action are mainly present in teachers’ exercise of authority concerning assessment and grading: a logic of consequences or a logic of appropriateness; a manufacturing logic or a service logic; and an instrumental logic or alternative logics. The relationship between logics of consequences and appropriateness is complex. It is difficult to say that one logic is the dominant force behind teachers’ exercise of authority. This is because of the constantly changing circumstances in the school environment. As for the manufacturing and service logics, the latter is dominant in assessment and grading. This does not influence decision-making as such, but enriches policy with a certain value production. Lastly, teachers claim that they instrumentally follow the guidelines in their exercise of authority. But at the same time alternative logics, such as gaming and cheating with the rules, are very much present in assessment and grading. Alternative logics distort teachers’ decision-making in several ways. These results show that logics of action are indeed tools that can help us to better understand what influences street-level bureaucrats’ exercise of authority, and how this contributes to policy-making. I conclude by suggesting how the use of logics of action as analytical tools can enhance our knowledge of street-level bureaucrats’ discretion in future research.