Made available in DSpace on 2016-08-29T15:33:21Z (GMT). No. of bitstreams: 1 tese_8607_MSC Thesis - Diorbert - FINAL(1).pdf: 3922223 bytes, checksum: b3e393525cb2dc99d26745cd7397ee7b (MD5) Previous issue date: 2015-02-27 / Enterprise Architecture (EA) promotes the establishment of a holistic view of the structure and way of working of an organization. One of the aspects covered in EA is associated with the organizations active structure, which concerns who undertakes organizational activities. Several approaches have been proposed in order to provide a means for representing enterprise architecture, among which ARIS, RM-ODP, UPDM and ArchiMate. Despite the acceptance by the community, existing approaches focus on different purposes, have limitations on their conceptual scopes and some have no real world semantics well-defined. Besides modeling approaches, many ontology approaches have been proposed in order to describe the active structure domain, including the ontologies in the SUPER Project, TOVE, Enterprise Ontology and W3C Org Ontology. Although specified for semantic grounding and meaning negotiation, some of proposed approaches have specific purposes and limited coverage. In addition, some of them are not defined using formal languages and others are specified using languages without well-defined semantics. This work presents a well-founded reference ontology for the organizational domain. The organizational reference ontology presented covers the basic aspects discussed in the organizational literature, such as division of labor, social relations and classification of structuring units. Further, it also encompasses the organizational aspects defined in existing approaches, both modeling and ontology approaches. The resulting ontology is specified in OntoUML and extends the social concepts of UFO-C.

Methods for analyzing the structural-acoustic power efficiency of active structures are developed. For this work we define the power efficiency as the ratio of the sound power radiated by a structure to the maximum possible radiated sound power. An active structure is defined as one that has electromechanical actuators distributed over its surface for the purpose of structural-acoustic excitation. The power efficiency of planar, baffled structures with arbitrary boundary conditions is examined using a combination of methods based on numerical integration, variational principles, and finite element analysis. The fundamental result of this work is that computing the power efficiency of an active structure reduces to the solution of two eigenvalue problems. The maximum possible sound power radiated by a planar, baffled structure is shown to be equivalent to the largest eigenvalue of the acoustic power transfer matrix. The structural-acoustic power efficiency is the solution of a separate generalized eigenvalue problem whose parameters include the location of the electromechanical actuators and the type of electromechanical actuation. The advantage of this metric over other measures of radiation efficiency is that 0 and 1 bound the structural-acoustic power efficiency. Furthermore, solving for the power efficiency as a function of frequency yields a measure of the bandwidth of the structural-acoustic actuator. Power efficiency is analyzed for point force actuation and distributed moment actuation. Numerical simulations demonstrate that maximizing the power efficiency requires that the magnitude and phase of the structural modal velocity vector be matched to that of the eigenvector that corresponds to the maximum eigenvalue of the acoustic power transfer matrix. Matching the modal velocity to the maximizing eigenvector produces a vibration shape that maximizes the sound power radiation of the structure. Individual actuators are not able to achieve high efficiency over a broad frequency range for both types of electromechanical actuation. Multiple-actuator arrays are able to achieve higher average efficiency at the expense of increased number of actuators. An optimization problem is then posed to maximize the structural-acoustic power efficiency by varying the location and size of distributed moment actuators. We demonstrate that an average efficiency on the order of 0.85 is possible over a large bandwidth through optimal placement and sizing of a set of four distributed moment actuators. Experimental results on a baffled plate demonstrate that correct phasing of the actuators results in velocity distributions that correlate well with predicted results. / Ph. D.

Although the concept of tensegrity structures was invented in the beginning of the twentieth century, the applications of these structures are limited, partially due to their low stiffness. The stiffness of tensegrities comes from topology, configuration, pre-stress and initial axial element stiffnesses.  The first part of the present work is concerned with finding the magnitude of pre-stress. Its role in stiffness of tensegrity structures is to postpone the slackening of cables. A high pre-stress could result in instability of the structure due to buckling and yielding of compressive and tension elements, respectively. Tensegrity structures are subjected to various external loads such as self-weight, wind or snow loads which in turn could act in different directions and be of different magnitudes. Flexibility analysis is used to find the critical load combinations. The magnitude of pre-stress, in order to sustain large external loads, is obtained through flexibility figures, and flexibility ellipsoids are employed to ensure enough stiffness of the structure when disturbances are applied to a loaded structure.  It has been seen that the most flexible direction is very much sensitive to the pre-stress magnitude and neither analytical methods nor flexibility ellipsoids are able to find the most flexible directions. The flexibility figures from a non-linear analysis are here utilized to find the weak directions.  In the second part of the present work, a strategy is developed to compare tensegrity booms of triangular prism and Snelson types with a truss boom. It is found that tensegrity structures are less stiff than a truss boom when a transversal load is applied. An optimization approach is employed to find the placement of the actuators and their minimum length variations. The results show that the bending stiffness can be significantly improved, but still an active tensegrity boom is less stiff than a truss boom. Genetic algorithm shows high accuracy of searching non-structural space. / QC 20110524

Made available in DSpace on 2016-12-23T14:33:33Z (GMT). No. of bitstreams: 1 Romulo Arpini - Parte 1.pdf: 1684521 bytes, checksum: 258db1cddcd5120d8961c4a55aa1c741 (MD5) Previous issue date: 2012-08-31 / The need to relate the various architectural domains captured in partial descriptions of an enterprise is addressed in virtually all enterprise modeling approaches. One of these domains, namely that of organizational behavior, has received significant attention in recent years in the context of business process modeling and management. Another important domain, that of organizational structure is strongly inter-related with the process domain. While the process domain focuses on how the business process activities are structured and performed, the organizational structure domain focuses on who performs these activities, i.e., which kinds of entities in an organization are capable of performing work. Given the strong connection between the organizational behavior and organizational resources, we argue that any comprehensive enterprise modeling technique should explicitly establish the relations between the modeling elements that represent organizational behavior, called here behavioral elements, and those used to represent the organizational resources (organizational actors) involved in these activities, called here active structure elements. Despite the importance of the relations between these architectural domains, many of the current enterprise architecture and business process modeling approaches lack support for the expressiveness of a number of important active structure allocation scenarios. This work aims to overcome these limitations by proposing a framework for active structure assignment that can be applied to enterprise architecture and business process modeling approaches. This framework enriches the expressiveness of existing techniques and supports the definition of precise active structure assignments. It is designed such that it should be applicable to a number of enterprise architecture and business process modeling languages, i.e., one should be able to use and apply different (enterprise and business process) modeling languages to the framework with minor changes / A necessidade de se relacionar os vários domínios arquiteturais capturados em descrições parciais de uma organização é, virtualmente, tratado em todas as abordagens de modelagem de arquiteturas organizacionais. Um destes domínios, particularmente chamado de comportamento organizacional, tem recebido atenção significativa nos últimos anos no contexto de modelagem e gerenciamento de processos de negócio. Outro domínio importante, chamado de estrutura organizacional, é fortemente inter-relacionado com o domínio de processo. Enquanto o domínio de processo foca em "como" as atividades de processos de negócio são estruturadas e executadas, o domínio de estrutura organizacional foca em "quem" executa essas atividades, i.e., quais tipos de entidades em uma organização são capazes de executar trabalho. Dada a forte conexão entre o comportamento organizacional e os recursos organizacionais, nós argumentamos que qualquer técnica de modelagem de arquitetura organizacional deve explicitamente estabelecer relações entre os elementos de modelagem que representam o comportamento organizacional, chamado aqui de elementos comportamentais e aqueles suados para representar recursos organizacionais (atores organizacionais) envolvidos nestas atividades, chamados aqui de elementos da estrutura ativa. Apesar da importância das relações entre esses domínios arquiteturais, muitas das abordagens de modelagem de processo de negócio e modelagem de arquiteturas organizacionais tem um suporte insuficiente para expressar uma quantidade importante de cenários de alocação da estrutura ativa. Este trabalho visa superar essas limitações propondo um framework para a atribuição da estrutura ativa que pode ser aplicado a abordagens de modelagem de processo de negócio e modelagem de arquitetura organizacionais. Esse framework enriquece a expressividade das técnicas existentes e dá suporte à definição de atribuições precisas da estrutura ativa. Ele é desenvolvido tal que pode ser aplicável a linguagens de modelagem de processo de negócio e linguagens de modelagem de arquiteturas organizacionais, i.e., é possível utilizar e aplicar diferentes linguagens de modelagem ao framework com mudanças mínimas

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