Description logics (DL) knowledge bases are often build by users with expertise in the application domain, but little expertise in logic. To support this kind of users when building their knowledge bases a number of extension methods have been proposed to provide the user with concept descriptions as a starting point for new concept definitions. The inference service central to several of these approaches is the computation of (least) common subsumers of concept descriptions. In case disjunction of concepts can be expressed in the DL under consideration, the least common subsumer (lcs) is just the disjunction of the input concepts. Such a trivial lcs is of little use as a starting point for a new concept definition to be edited by the user. To address this problem we propose two approaches to obtain "meaningful" common subsumers in the presence of disjunction tailored to two different methods to extend DL knowledge bases. More precisely, we devise computation methods for the approximation-based approach and the customization of DL knowledge bases, extend these methods to DLs with number restrictions and discuss their efficient implementation.

El razonamiento y cambio de bases de conocimiento o knowledge bases (KBs) por sobre las inconsistencias, es de extrema importancia en áreas como la medicina y el derecho. Esto es, razonar y provocar la evolucion del conocimiento sin necesidad de restaurar la consistencia, sino proveyendo una forma de tolerancia a ella. La argumentacion puede brindar la posibilidad de dar con ambos problemas. Primeramente, me-diante la construcción de un marco argumentativo o argumen-tation framework (AF) a partir de la KB inconsistente, pode-mos decidir si aceptar o rechazar una cierta conclusion o claim a través de la interacción entre argumentos y contra-argumentos. Segundo, mediante el manejo de la dinámica de argumentos del AF, podemos dar con la dinámica del conoci-miento de la KB inconsistente subyacente.Por un lado, propondremos una nueva familia de marcos argumentativos abstractos a los cuales referimos como generalizados, e identificamos como generalized abstract argumentation frameworks (GenAF), debido a su habilidad de adaptacion a diferentes lenguajes de representación. El objetivo es proveer un marco argumentativo, no completamente abstracto, para razonar por sobre las inconsistencias de KBs representadas a través de cualquier lenguaje que se sepa conforme algún fragmento de primer-orden. Las semánticas estándar de Dung son adaptadas para construir la maquinaria de razonamiento del GenAF. En lo que constituye un primer enfoque a revision de creencias en esta tesis, se propondrá un operador de debugging para la KB subyacente definido sobre las semán-ticas argumentativas para GenAFs como un tipo de consoli-dación: operación propuesta por Hansson para restaurar consistencia a KBs. Por ello, nos basaremos sobre sus postula-dos usuales para caracterizar axiomaticamente la operación de debugging propuesta, mostrando el correspondiente teorema de representación. Luego, proponemos la reificación del lenguaje abstracto para argumentos del GenAF al lenguaje básico de descripción ALC. Esto muestra la flexibilidad del formalismo presentado y una forma de aplicar argumentación a ontologías para razonar sobre las inconsistencias. Finalmen-te, la operación de debugging provee una herramienta para reparar inconsistencias y conceptos insatisfacibles, restau-rando consistencia-coherencia a las ontologías ALC. La dinámica de argumentos ha recientemente atraído atención y aunque algunos enfoques han sido propuestos, una axioma-tización completa dentro de la teoría de revisión de creen-cias constituyó un resultado pendiente hasta el momento. Una revision surge cuando deseamos que las semánticas argumentativas acepten un nuevo argumento. La teorıa del cambio argumentativo o Argument Theory Change (ATC) define operadores de revision que modifican un AF mediante el análisis de árboles de dialéctica argumentos como nodos y ataques como arcos como la semántica argumentativa adoptada. Presentaremos un simple enfoque a ATC basado en KBs proposicionales. Esto nos permite manejar el cambio de KBs inconsistentes basandonos en la teoría clásica de revi-sión de creencias, aunque al contrario de lo que ella indica, se evitará la restauración de consistencia de la KB a trabajar. Subsecuentemente, un conjunto de postulados de racionali-dad será adaptado a argumentación y finalmente, el modelo de cambio propuesto será relacionado a los postulados a través del correspondiente teorema de representación. Seguidamente, los resultados serán extendidos a description logics, para manejar el razonamiento y evolución ontológicos con tolerancia a inconsistencias. / Reasoning and change over inconsistent knowledge bases (KBs) is of utmost relevance in areas like medicine and law. Argumentation may bring the possibility to cope with both problems. Firstly, by constructing an argumentation frame-work (AF) from the inconsistent KB, we can decide whether to accept or reject a certain claim through the interplay among arguments and counterarguments. Secondly, by handling dynamics of arguments of the AF, we might deal with the dynamics of knowledge of the underlying inconsistent KB. On the one hand, we propose a new family of abstract argu-mentation frameworks which we refer as generalized (iden-tified through the acronym GenAF), due to its ability of adapting to different representation languages. The objective is to provide a not so, but still, abstract argumentation framework for reasoning over inconsistent knowledge bases (KBs) represented through any language known to conform to some first-order fragment. The well known Dungs standard semantics are adapted to construct the GenAFs reasoning machinery. Constituting the first approach to belief revision in this thesis work, we propose a debugging operator for the underlying KB defined upon the argumentation semantics for GenAFs, as a kind of belief revisions consolidation. A consolidation is a well known Hanssons operation for restoring consistency to KBs, therefore, we rely upon its usual postulates to axiomatically characterize the debugging operation proposed here, showing the corresponding representation theorem. Afterwards, we propose a reification of the GenAFs abstract language for arguments to the basic ALC description logic. This shows both the flexibility of the formalism presented, and a way to apply argumentation for reasoning over inconsistent ontologies, subject of utmost relevance in areas like medicine and law. Finally, the debugging operation provides a tool for debugging inconsistent ontologies and repairing unsatisfiable concepts, for restoring both consistency and coherency to ALC ontologies. Dynamics of arguments has recently attracted attention and although some approaches have been proposed, a full axiomatization within the theory of belief revision was still missing. A revision arises when we want the argumentation semantics to accept an argument. Argument Theory Change (ATC) encloses the revision operators that modify the AF by analyzing dialectical trees arguments as nodes and attacks as edges as the adopted argumentation semantics. We present a simple approach to ATC based on propositional KBs. This allows to manage change of incon-sistent KBs by relying upon classic belief revision, although contrary to it, consistency restoration of the KB is avoided. Subsequently, a set of rationality postulates adapted to argumentation is given, and finally, the proposed model of change is related to the postulates through the corresponding representation theorem. Afterwards, the results are extended to description logics, to handle ontology reasoning and evolution with tolerancy to inconsistency.

This research paper identifies the disciplinary differences of stakeholders and its effects on working cross-functional in the context of machine learning. This study specifically focused on 1) how stakeholders with disciplinary differences interpret a search system, and 2) how the multi-disciplines should be managed in an organization. This was studied through 12 interviews with stakeholders from design disciplines, product management, data science and machine learning engineering, followed by a focus group with a participant from each of the different disciplines. The findings were analyzed through a thematic analysis and institutional logics and concluded that the different logics had a high impact on the stakeholders’ understanding of the search system. The research also concluded that bridging the gap between the multi-disciplinary stakeholders are of high importance in context of machine learning.

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The aging of our society is well known, with policy makers and analysts forecasting enormous increases in people living with chronic illness and disabilities (AoA, 2009). Less well known is that services for older adults and younger people with disabilities - historically separated by different funding streams, service systems, and workforces - have increasingly merged (Putnam, 2007). The movement to combine services for older adults and younger persons with disabilities is reflected in the creation of a hybrid organization - Aging and Disability Resource Centers (ADRCs) - designed to combine services for both populations (O'Shaughnessy, 2011; Putnam, 2011). Using ADRCs as the principal organizational strategy to combine aging and disability services has been challenging, primarily because these organizations have different histories and service philosophies (Kane, 2007; Putnam & Stoever, 2007; DeJong, 1979). Independent living centers, who serve people of all ages with disabilities, have a service philosophy that emphasizes `consumer direction', characterized by consumer control, advocacy, and peer models. While the aging service delivery philosophy is based in a medical model of care where care plans are developed by medical providers and services are provided by professionals in order to protect the well-being of older adults (DeJong, 1986; Simon-Rusinowitz & Hofland, 1993). The purpose of this dissertation is to examine the experiences of ADRCs to combine aging and disability services. The study employs institutional logics theory and a mixed-methods design to assess whether a unified organizational philosophy for these services can be identified. In this dissertation, I found that there were competing logics between directors located at aging organizations when compared to directors at Independent Living Centers. These competing logics were also present among their staff in these organizations. As a mechanism to manage the co-existing logics, I found that the joint activity of collaborating in creating a training program to describe overarching service philosophies helped to unify the two organizations. Additionally, I found that the workers located at aging organizations who took the training had increases in their understanding of the professional logic of consumer control, which is dominant in the disability organizations; therefore, this training helped in managing the co-existence of logics.

Description logics are knowledge representation and reasoning formalisms which represent conceptual knowledge on an abstract logical level. Concrete domains are a theoretically well-founded approach to the integration of description logic reasoning with reasoning about concrete objects such as numbers, time intervals or spatial regions. In this paper, the complexity of combined reasoning with description logcis and on concrete domains is investigated. We extend ALC(D), which is the basic description logic for reasoning with concrete domains, by the operators 'feature agreement' and 'feature disagreement'. For the extended logic,called ALCF(D), an algorithm for deciding the ABox consistency problem is devised. The strategy employed by this algorithm is vital for the efficient implementation of reasoners for description logics incorporating concrete domains. Based on the algorithm, it is proved that the standard reasoning problems for both logics ALC(D) and ALCF(D) are PSpace-complete - provided that the satisfiability test of the concrete domain used is in PSpace. / This is an extended version of the article in: Proceedings of IJCAI-99, Stockholm, Sweden, July 31-August 6, Morgan Kaufmann Publ. In ., San Mateo, CA, 1999

Number restrictions are concept constructors that are available in almost all implemented description logic systems. However, even though there has lately been considerable effort on integrating expressive role constructors into description logics, the roles that may occur in number restrictions are usually of a very restricted type. Until now, only languages with number restrictions on atomic roles and inversion of atomic roles, or with number restrictions on intersection of atomic roles have been investigated in detail. In the present paper, we increase the expressive power of description languages by allowing for more complex roles in number restrictions. As role constructors, we consider composition of roles (which will be present in all our languages), and intersection, union and inversion of roles in different combinations. We will present one decidability result (for the basic language that extends ALC by number restrictions on roles with composition), and three undecidability results for three different extensions of the basic language.

This study explores the contradiction between the ways the institutional field of sustainable development has for decades been defined conceptually by a temporal sense of equity, or the aim of meeting the needs of both present and future generations, and the glaring lack of definition for the concept. Through discursive analysis, this study finds sustainable development discourse to precariously conceptualize equity according to multiple, incompatible institutional logics, and to conceptualize time in highly ambiguous ways. Further, the ambiguity of time appears to have corrosive effects on the meaningfulness of equity as a concept, and to provide a mechanism by which institutional actors within the field of sustainable development can evade accountability. These dynamics suggest power and preferential outcomes will be retained by the people of the present, and inherently harm generations to come. In this way, this study questions whether sustainable development defined according to temporal equity is truly “the future we want,” or rather just the future we want to want, but are unwilling to bring about.

The problem of rewriting a concept given a terminology can informally be stated as follows: given a terminology T (i.e., a set of concept definitions) and a concept description C that does not contain concept names defined in T , can this description be rewritten into a 'related better' description E by using (some of) the names defined in T ? In this paper, we first introduce a general framework for the rewriting problem in description logics, and then concentrate on one specific instance of the framework, namely the minimal rewriting problem (where 'better' means shorter, and 'related' means equivalent). We investigate the complexity of the decision problem induced by the minimal rewriting problem for the languages FL0, ALN, ALE, and ALC, and then introduce an algorithm for computing (minimal) rewritings for the languages ALE and ALN. Finally, we sketch other interesting instances of the framework. Our interest for the minimal rewriting problem stems from the fact that algorithms for non-standard inferences, such as computing least common subsumers and matchers, usually produce concept descriptions not containing defined names. Consequently, these descriptions are rather large and hard to read and comprehend. First experiments in a chemical process engineering application show that rewriting can reduce the size of concept descriptions obtained as least common subsumers by almost two orders of magnitude. / Please download the revised version LTCS-00-04 containing revised proofs of the technical results. / An abridged version of this report appeared in the Proceedings of the International Conference on Knowledge Representation and Reasoning (KR'2000).

Recent research in the field of Description Logic (DL) investigated the complexity of the satisfiability problem for description logics that are obtained by enriching the well-known DL ALCQ with more complex set and cardinality constraints over role successors. The algorithms that have been proposed so far, despite providing worst-case optimal decision procedures for the concept satisfiability problem (both without and with a terminology) lack the efficiency needed to obtain usable implementations. In particular, the algorithm for the case without terminology is non-deterministic and the one for the case with a terminology is also best-case exponential. The goal of this thesis is to use well-established techniques from the field of numerical optimization, such as column generation, in order to obtain more practical algorithms. As a starting point, efficient approaches for dealing with counting quantifiers over unary predicates based on SAT-based column generation should be considered.:1. Introduction 2. Preliminaries 2.1. First-order logic 2.2. Linear Programming 2.3. The description logic ALCQ 2.4. Extending ALCQ with expressive role successor constraints 2.4.1. The logic QFBAPA 2.4.2 The description logic ALCSCC 3. The description logic ALCCQU 3.1. A normal form for ALCCQU 3.2. ALCQt as an equivalent formulation of ALCCQU 3.2.1. ALCQt is a sublogic of ALCCQU 3.2.2. ALCCQU is a sublogic of ALCQt 3.3. Model-theoretic characterization of ALCQt 3.3.1. ALCQt-bisimulation and invariance for ALCQt 3.3.2. Characterization of ALCQt concept descriptions 3.4. Expressive power 3.4.1. Relative expressivity of ALCQ and ALCCQU 3.4.2. Relative expressivity of ALCCQU and ALCSCC 3.5. ALCCQU as the first-order fragment of ALCSCC 4. Concept satisfiability in ALCCQU 4.1. The first-order fragment CQU 4.2. Column generation with SAT oracle 4.2.1. Column generation and CQU 4.2.2. From linear inequalities to propositional formulae 4.2.3. Column generation and ALCCQU 4.3. Branch-and-Price for ALCCQU concept satisfiability 4.4. Correctness of ALCCQU-BB 4.4.1. Complexity of ALCCQU-BB 5. Conclusion - Bibliography