There is a growing appreciation for the insight mathematical models can yield on biological systems. In particular, due to the challenges inherent in experimental observation of disease progression, models describing the genesis, growth and evolution of cancer have been developed. Many of these models possess the common feature that one particular type of cellular population initiates a further, distinct population. This thesis explores two models containing this feature, which also employ branching processes to describe population growth. Firstly, we consider a deterministically growing wild type population which seeds stochastically developing mutant clones. This generalises the classic Luria- Delbruck model of bacterial evolution. We focus on how differing wild type growth manifests itself in the distribution of clone sizes. In our main result we prove that for a large class of wild type growth, the long-time limit of the clone size distribution has a general two-parameter form, whose tail decays as a power-law. In the second model, we consider a fully stochastic system of cells in a growing population that can undergo birth, death and transitions. New cellular types appear via transitions, examples of which are genetic mutations or migrations bringing cells into a new environment. We concentrate on the scenario where the original cell type has the largest net growth rate, which is relevant for modelling drug resistance, due to fitness costs of resistance, or cells migrating into contact with a toxin. Two questions are considered in our main results. First, how long do we wait until a cell with a specific target type, an arbitrary number of transitions from the original population, exists. Second, which particular sequence of transitions initiated the target population. In the limit of small final transition rates, simple, explicit formulas are given to answer these questions.

Su Yat Fan. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 91-95). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Our Objective --- p.4 / Chapter 1.3 --- The Organization of the Thesis --- p.5 / Chapter 2 --- Related Works --- p.7 / Chapter 2.1 --- Semi-structured Data --- p.7 / Chapter 2.1.1 --- What are Semi-structured Data? --- p.8 / Chapter 2.1.2 --- Examples of Semi-structured Data --- p.9 / Chapter 2.2 --- Object Exchange Model --- p.10 / Chapter 2.3 --- Regular Path Expressions --- p.12 / Chapter 2.4 --- Graph Schemas --- p.13 / Chapter 2.4.1 --- Accurate Graph Schemas: DataGuides --- p.15 / Chapter 2.4.2 --- Approximate Graph Schemas --- p.17 / Chapter 2.4.3 --- Conceptual Graphs (CG) --- p.19 / Chapter 2.5 --- Chapter Summary --- p.25 / Chapter 3 --- Query Evaluation and Characteristics of Conceptual Graphs --- p.27 / Chapter 3.1 --- Generation of Data Graphs --- p.28 / Chapter 3.2 --- Conceptual Graphs with Respect to Different Types of Data Graphs --- p.29 / Chapter 3.2.1 --- Experimental Setup --- p.29 / Chapter 3.2.2 --- Experimental Results --- p.30 / Chapter 3.3 --- Query Evaluation --- p.34 / Chapter 3.4 --- The Effect of Traversal Orders over Conceptual Graphs --- p.39 / Chapter 3.4.1 --- Experimental Setup --- p.39 / Chapter 3.4.2 --- Experimental Results --- p.40 / Chapter 3.5 --- Chapter Summary --- p.46 / Chapter 4 --- Problems in Conceptual Graphs --- p.47 / Chapter 4.1 --- False Paths in Conceptual Graphs --- p.50 / Chapter 4.2 --- Utility Function --- p.51 / Chapter 4.3 --- Information Incompleteness in the Construction Process --- p.53 / Chapter 4.4 --- Chapter Summary --- p.54 / Chapter 5 --- Refinement of the Utility Function --- p.55 / Chapter 5.1 --- """Attributes Or Roles"" Instead of ""Attributes and Roles""" --- p.56 / Chapter 5.2 --- Roles --- p.57 / Chapter 5.2.1 --- The New Utility Function with Only Roles Involved --- p.57 / Chapter 5.2.2 --- Query Evaluation Using Roles Only --- p.58 / Chapter 5.3 --- Attributes --- p.63 / Chapter 5.3.1 --- The New Utility Function Based on Attributes Only --- p.63 / Chapter 5.3.2 --- Query Evaluation Using Attributes Only --- p.64 / Chapter 5.4 --- A Reliability Test for Attribute-only Utility Function --- p.66 / Chapter 5.5 --- Chapter Summary --- p.70 / Chapter 6 --- New Operators for Conceptual Graph Construction --- p.74 / Chapter 6.1 --- The Original Algorithm --- p.74 / Chapter 6.2 --- Revised Algorithm with New Operators --- p.75 / Chapter 6.3 --- Query Evaluation of the Revised Algorithm --- p.79 / Chapter 6.3.1 --- Experimental Setup --- p.79 / Chapter 6.3.2 --- Evaluation Results --- p.80 / Chapter 6.4 --- Chapter Summary --- p.85 / Chapter 7 --- Conclusions --- p.87 / Chapter 7.1 --- Future Work --- p.89 / Bibliography --- p.91

Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro / Dans les grammaires traditionnelles de la langue portugaise, l'étude sur l'antonomase, figure de langage qui désigne le procédé de passage d'un nom propre à un nom commun et vice-versa, est aperçu comme étant soit lié à la notion de métaphore, ou soit lié à la relation entre la partie et l'ensemble, autrement dit, la métonymie. Dans la plupart des cas, les exemples issus des méthodes traditionnelles sont hors contexte, c'est-à-dire, ils ne viennent pas d'un usage discursif- dialogique de la langue. L'objectif principal de cette thèse c'est de faire une réflexion sur le potentiel sémiotique-fonctionnel et cognitif des noms propres dans les antonomases discursives, c'est-à-dire, de celles qui ne sont pas encore dans les dictionnaires, puisqu'elles sont temporaires, et, conséquemment, son interprétation fait partie du domaine du traitement discursif, ou lénonciation. Ayant comme base théorique la théorie des Espaces Mentaux dans un deuxième temps, reconnue comme la théorie de l'Intégration Conceptuelle (FAUCONNIER; TURNER, 2002) et la théorie de l'Iconicité Verbale, développé par Simões (2009), basée sur les études sémiotiques de Charles Sanders Peirce, nous analyserons les suivants aspects de l'antonomase discursive des noms propres: la forme du nom propre, c'est-à-dire, sa plasticité, qui est la caractéristique central de l'iconicité schématique, et l'iconicité isotopique, qui agi comme une sorte de conducteur thématique pour la formation du sens d'un texte. Ces deux types d'iconicité sont inclus dans un réseau plus ample de signes nominé l'iconicité verbale, ou lexical (SIMÕES, 2004), qui englobent non seulement les effets d'ordre discursif mais aussi d'ordre stylistique. Ainsi, en concevant l'étude des antonomases discursives des noms propres d'après une perspective sémiotique-discursive et cognitive, nous croyons avoir franchi une étape de plus dans l'étude des éléments lexicaux en tant que organisateurs du sens d'un texte / Nas gramáticas tradicionais da língua portuguesa, o estudo sobre a antonomásia, figura de linguagem que designa o processo de passagem de um nome próprio a um nome comum e vice-versa, é visto ora ligado ao conceito de metáfora, ora ligado à relação parte- todo, isto é, à metonímia. Na maioria das vezes, os exemplos mostrados nessas abordagens tradicionais estão descontextualizados, ou seja, não são retirados de um emprego discursivo- dialógico da língua. O principal objetivo desta tese é fazer uma reflexão sobre o potencial semiótico- funcional e cognitivo dos nomes próprios nas antonomásias discursivas, ou seja, aquelas que ainda não estão dicionarizadas, porque são temporárias, e, consequentemente, sua interpretação pertence ao âmbito do processamento discursivo. Tendo como base teórica a teoria dos Espaços Mentais em seu segundo momento, reconhecida como teoria da Integração Conceptual (FAUCONNIER; TURNER, 2002), e a teoria da Iconicidade Verbal, desenvolvida por Simões (2009), baseada nos estudos semióticos de Charles Sanders Peirce, analisar-se-ão, nesta tese, os seguintes aspectos do nome próprio nas antonomásias discursivas: a forma do nome próprio, ou seja, sua plasticidade, que é a característica central da iconicidade diagramática, e a iconicidade isotópica, que age como uma espécie de condutor temático para a formação de sentido de um texto. Esses dois tipos de iconicidade se inserem numa rede mais ampla de signos denominada iconicidade verbal, ou lexical (SIMÕES, 2004), que abrange efeitos tanto de ordem discursiva (discursivização) como de ordem estilística. Assim, ao se conceber o estudo das antonomásias discursivas do nome próprio em uma perspectiva semiótico- discursiva e cognitiva, ter-se-á dado mais um passo nos estudos dos itens lexicais que atuam como organizadores de sentido de um texto

This thesis offers in introduction into ontology in philosophy and informatics. In philosophy, ontology is the study of the most general features of reality. In the field of Informatics the term ontology is starting to be used more often and numerous "ontological approaches" have been proposed recently. In the chapter about ontology in philosophy the meaning is explained on the background of history of philosophy. There generally three meanings of ontology: as a theoretical discipline, as a theory about the structure of reality and as a concrete artefact. It is argued that every science needs a sound ontological base and that the need for ontology increases in times of scientific discovery. The aim of the chapter about ontology in informatics is to show the need and application possibilities for an ontological approach in conceptual modelling, domain engineering and in the area of semantic web. In the end there is a discussion of the terminological confusion about ontology in informatics.

Esta dissertação trata da aeração induzida em vertedores com objetivo de mitigar os efeitos da cavitação sobre os mesmos. A análise bibliográfica do tema está calcada na introdução ao mecanismo da cavitação e no levantamento do estado da arte a partir dos trabalhos pioneiros, nos clássicos e nos recentes. Com base nos princípios da física: Conservação de Massa e Primeira Lei da Termodinâmica, foi desenvolvido um modelo matemático para aeração induzida em vertedores. O modelo proposto, após ser analisado do ponto de vista de sua consistência, foi avaliado em comparações com resultados fornecidos por outros pesquisadores, obtidos através de modelos físicos reduzidos. Os resultados obtidos pelo modelo matemático proposto correspondem a boas estimativas das grandezas envolvidas na aeração induzida em vertedores, o que credencia o modelo proposto como uma ferramenta apropriada para projetos de engenharia hidráulica e futuros desenvolvimentos científicos. / This study adress prompt aeration in spillways reaching to reduce the cavitation effects on them. References were based on introduction to cavitation machanism and, state of art survey, to leave on not only earlier studies, but also on classical and most recent ones. Based on principles of Physics, such as Mass Conservation and the First Law of Thermodynamics, a mathematical model has been developed as an example of prompt aeration in spillways. After extensive consistency analyses the proposed model has been validated by comparing different results furnished by studies on physical reduced models by other researchers. Results obtained from the mathematical model proposed here correspond to good estimates of greatnesses involved in prompt aeration is spillways and that turns the proposed model into an adequate tool for Hydraulic Engineering projects and for future scientifics stydies.

Este trabalho relata um estudo realizado para medir a eficiência da abordagem conceitual no ensino da saúde, tendo em vista oferecer subsídios para o planejamento do ensino da saúde. A matéria saúde na escola de 1º Grau foi organizada numa hierarquia conceitual e experiências de aprendizagem planejadas visando à consecução de objetivos cognitivos, afetivos e práticos em relação à saúde. O estudo foi desenvolvido em uma escola pública de São Paulo. Foram tomadas três classes para realizar o estudo. Com o grupo experimental foi usada a abordagem conceitual no ensino; no outro grupo, a metodologia foi escolhida pelo professor, que utilizou a abordagem tradicional; com o grupo controle não se desenvolveu nenhuma atividade específica de ensino da saúde. Comparados os resultados, constatou-se que houve uma diferença significante na aprendizagem do grupo experimental, maior que nos outros grupos. O estudo concluiu que a abordagem conceitual no ensino da saúde do primeiro grau e mais eficiente do que a abordagem tradicional para identificar, selecionar, organizar e desenvolver saúde como materia curricular. / This paper describes a study carried out to measure the efficiency of the conceptual approach in health teaching, in order to contribute to the planning health, teaching in elementary schools. Health was organized in a conceptual hierarchy, and learning experiences were planned covering behavioral objectives to achieve health at the levels cognitive, affective and action. The program was developed in a public school of S.Paulo. Theree classes were chosen: at the experimental the conceptual approach was used for teaching; in the second class the methodology was selected by the teacherwho used the traditional approach; at the third, as the control class, planned activities to teach health were carried out. The results showed that there was a significant difference in learning for the experimental group much greater than in the other classes. The study concludes that the conceptual approach to teach health is more efficient than the traditional to identify, select, organize and develop health as a subject of the school curriculum.

A utilização da Web com objetivos educacionais e de treinamento, vem se caracterizando como uma das grandes áreas de pesquisa e aplicação da informática no dia-a-dia das pessoas e empresas. A tecnologia de workflow poderá contribuir decisivamente para a qualidade dos cursos na Web, permitindo que a informação seja apresentada de maneira interativa conduzindo o aprendiz a uma atitude dinâmica, transformando-o num elemento ativo que manipula os recursos na seqüência e velocidade desejados, o que contribui para um aprendizado mais eficiente. A utilização de workflow associada a tecnologia de Agentes fornece o potencial de uma navegação não-linear, onde o usuário dispõe de flexibilidade para determinar o fluxo de apresentação das informações, não vinculado a uma cadeia seqüencial de conteúdos que foram hierarquicamente construídos. Neste contexto, o presente trabalho, apresenta um modelo de aluno especificado através de um modelo de Workflow. Este modelo foi alcançado por meio da análise das interações de uma amostra de alunos em um curso na Web, observando a Teoria Cognitiva dos Estilos de Aprendizagem e a ordem de execução das atividades do curso pelos alunos. A finalidade desta modelagem por workflow tem como objetivo contribuir nas atividades de execução, coordenação, monitoramento e adaptação em cursos na Internet. / The use of the Web with educational and training objectives may be identified as one of the great research and application areas of computer science today. The workflow technology will be able to contribute decisively for the quality of the Web courses, allowing the information to be presented in interactive way leading the apprentice to a dynamic attitude, transforming the content management into an active element that manipulates the resources in the desired sequence and speed, contributing for a more efficient learning. The use of dynamic workflows associated the agent technology supplies the potential of a nonlinear navigation, where the user takes profit of system flexibility to determine the flow of presentation of the information, not tied with a sequential chain of contents or a hierarchical structure as they have being constructed. In this context, the present work, develop a student model specified through a workflow model. This model was reached by the analysis of the interactions of a sample of students in a Web course. The Cognitive Theory of the Styles of Learning and the order of execution of the activities of the course for the students have being considered in the model development. The purpose of this workflow modelling was to contribute in the development of a comprehensive model of activities execution, coordination, monitoring and adaptation in courses in the Internet.

This thesis presents the concept of hybrid semantic-document models to aid information management when using standards for complex technical domains such as military data communication. These standards are traditionally text based documents for human interpretation, but prose sections can often be ambiguous and can lead to discrepancies and subsequent implementation problems. Many organisations produce semantic representations of the material to ensure common understanding and to exploit computer aided development. In developing these semantic representations, no relationship is maintained to the original prose. Maintaining relationships between the original prose and the semantic model has key benefits, including assessing conformance at a semantic level, and enabling original content authors to explicitly define their intentions, thus reducing ambiguity and facilitating computer aided functionality. Through the use of a case study method based on the military standard MIL-STD-6016C, a framework of relationships is proposed. These relationships can integrate with common document modelling techniques and provide the necessary functionality to allow semantic content to be mapped into document views. These relationships are then generalised for applicability to a wider context. Additionally, this framework is coupled with a templating approach which, for repeating sections, can improve consistency and further enhance quality. A reflective approach to model driven web rendering is presented and evaluated. This reflective approach uses self-inspection at runtime to read directly from the model, thus eliminating the need for any generative processes which result in data duplication across source used for different purpose.

Les tâches dans les environnements virtuels immersifs sont associées à des techniques et à des dispositifs d’interaction 3D (e.g. la sélection d’objets 3D à l’aide de la main virtuelle via un flystick). Alors que les environnements et les tâches deviennent de plus en plus complexes, les techniques ne peuvent plus être les mêmes pour chaque application, voire pour les différentes situations au sein d’une application. Une solution est d’adapter l’interaction en fonction des besoins de la situation pour améliorer l’utilisabilité. Ces adaptations peuvent être effectuées manuellement par le concepteur ou l’utilisateur, ou automatiquement par le système créant ainsi une interaction adaptative. La formalisation d’une telle assistance automatique nécessite la gestion d’informations pertinentes au vu de la situation. L’ensemble de ces informations fait émerger le contexte de l’interaction. L’assistance adaptative obtenue en raisonnant à partir de ces informations est ainsi consciente du contexte. De nombreuses possibilités existent pour l’obtenir. Notre objectif est une gestion du contexte qui préserve ses degrés élevés d’expressivité et d’évolutivité tout en étant facile à intégrer. Nous proposons une modélisation de ce problème par des graphes conceptuels basés sur une ontologie et gérés par un moteur externe en logique du premier ordre. Le moteur est générique et utilise une base de connaissance contenant des faits et des règles, qui peuvent être changés dynamiquement. Nous avons intégré une notion de confiance, afin d’établir l’adéquation d’une situation à la base de connaissances. La confiance des réactions est comparée à leur impact afin de ne garder que les pertinentes tout en évitant de saturer l’utilisateur. Les applications utilisent des outils qui peuvent être contrôlés par le moteur. Des capteurs permettent d’extraire des informations sémantiques pour le contexte. Des effecteurs permettent d’agir sur l’application et d’obtenir des adaptations. Un jeu d’outils et une base de connaissance pour l’interaction 3D ont été créés. De nombreuses étapes sont introduites dans la base de connaissance pour de bonnes combinaisons et une réflexion indépendante d’outils spécifiques. Nos premières applications illustrent la compréhension de la situation, dont les intérêts et difficultés de l’utilisateur, et le déclenchement d’assistances adaptées. Une étude hors ligne montre ensuite l’accès et l’évolution des étapes du moteur selon la situation. Le raisonnement sémantique générique obtenu est alors expressif, compréhensif, extensif et modifiable dynamiquement. Pour l’interaction 3D, il permet une assistance universelle automatique, ponctuelle ou manuelle à l’utilisateur et des analyses hors-lignes d’activités ou de conceptions pour le concepteur. / Tasks in immersive virtual environments are associated with 3D interaction techniques and devices (e.g. the selection of 3D objects with the virtual hand and a flystick). As environments and tasks become more and more complex, techniques can not remain the same for each application, even for every situations of a single application. A solution is to adapt the interaction depending on the situation in order to increase usability. These adaptations can be done manually by the designer or the user, or automatically by the system thus creating an adaptative interaction. Formalisation of such assistance needs the management of pertinent information regarding the situation. Those items of information make the context emerge from the interaction. The adaptative assistance obtained by reasoning on this information is then context-aware. Numerous possibilities can be used to build one. Our objective is a context management that preserves its high degrees of expressiveness and evolutivity while being easy to plug in. We have built a model for this issue using conceptual graphs based on an ontology and managed externally with a first order logic engine. The engine is generic and uses a knowledge base with facts and rules which can be dynamically changed. We have added a confidence notion, in order to establish a situation similarity to the knowledge base. Reactions’confidences are compared to their impacts so as to keep only the pertinent ones while avoiding user overload. Applications have tools that can be controlled by the engine. Sensors are used to extract semantic information for the context. Effectors are used to act upon the application and to have adaptations. A tools set and a knowledge base have been created for 3D interaction. Numerous steps have been added in the knowledge base to obtain good combinations and a reasoning independent from specific tools. Our first applications shows the situation understanding, including user interests and difficulties, and the triggering of pertinent assistances. An off-line study illustrates the access and evolution of the internal engine steps. The built generic semantic reasoning is expressive, understandable, extensive and modifiable dynamically. For 3D interaction, it allows universal assistances for the user that can be automatic, punctual or manual and off-line activities or conceptions analysis fort he designers.

In today's competitive global market, there is an ever-increasing demand for highly skilled engineers equipped to perform in teams dispersed over several time-zones by geography. Aerospace Partners for the Advancement of Collaborative Engineering (AerosPACE) is a senior design capstone program co-developed by academia and industry to help students develop the necessary skills to excel in the aerospace industry by challenging them to design, build, and fly an unique unmanned aerial vehicle (UAV). Students with little to no experience designing UAVs are put together in teams with their peers from geographically dispersed universities. This presents a significant challenge for the students in assimilating and applying aircraft design principles, using and interpreting output from analysis tools in multiple disciplines, and communicating their findings with their team members in an effective way. This thesis documents the development of a collaborative design tool for the generation and evaluation of small-scale electric-powered UAV concepts in AerosPACE. The integrated design and optimization software CCADE (Collaborative Conceptual Aircraft Design Environment) enables the immersion of team members from different universities in a software environment which shares design information and analysis results in a central database. Input files for use by open-source analysis tools are automatically generated, and output files read in and displayed in a user-friendly graphical interface. Analysis codes for initial sizing, geometry, airfoil selection, aerodynamics, propulsion, stability and control, and structures are included in the software. Optimization methods are proposed for implementation in future versions of CCADE to explore the breadth of the design space and help students understand the sensitivity of their design to certain key parameters. Testing of CCADE by students during the 2014-2015 AerosPACE course showed an increased volume of explored concepts and prompted questions from students to fill gaps in understanding of fundamental principles. Suggestions for increased student acceptance and use of the software are given. Through its unique architecture and application, CCADE aims to increase productivity and teamwork among AerosPACE participants by increasing the number of concepts which can be fully analyzed, enabling broader exploration of the feasible design space to produce unique and innovative aircraft configurations, and allowing teammates to share thoughts and learning via a shared design and analysis work-space.