Esta dissertação apresenta uma revisão histórica dos trabalhos acerca de superfícies minimais, ressaltando a pertinência da analogia entre a busca de superfícies de mínima área e a busca de formas de membranas estruturais sujeitas a um estado de tensões superficiais, homogêneo e isótropo. São colocados alguns conceitos geométricos das superfícies parametrizáveis, com base na geometria diferencial, a fim de realizar o equilíbrio diferencial de membranas e determinar as suas equações de equilíbrio. Além disso, é apresentada uma metodologia puramente geométrica para a determinação de superfícies minimais, baseada na minimização do funcional da área, dado pela soma das áreas das facetas triangulares nas quais a superfície é discretizada. O trabalho discute a formulação matemática do problema e apresenta resultados obtidos tanto por meio das rotinas implementadas no software MATLAB quanto por meio daquelas da biblioteca de otimização deste mesmo software. Finalmente, são realizados alguns exemplos e um teste de convergência, comparando as superfícies resultantes dos métodos numéricos com suas respectivas respostas analíticas. A geometria final de um dos exemplos é verificada por meio da analogia dos filmes de sabão, realizando-se uma análise não-linear de equilíbrio através do software Ansys. As soluções foram bastante satisfatórias, resultando em formas muito próximas das analíticas e com pequenos erros relativos das áreas. O teste de convergência também comprovou que o refinamento da discretização leva a uma solução mais próxima da desejada. Portanto, os procedimentos apresentados podem ser empregados no processo de busca da forma de membranas estruturais. / This dissertation presents a historical review on the theoretical developments on minimal surfaces, highlighting the important analogy between the problems of finding minimal area surfaces and finding membrane surfaces with homogeneous and isotropic stress fields. Some geometric concepts of the parametric surfaces are placed, on the basis of differential geometry, in order to do the differential equilibrium of membranes and to achieve its equilibrium equations. Moreover, a purely geometric methodology for the determination of minimal surfaces is presented, based on the minimization of the area functional, which is computed by the simple addition of a finite number of triangular facet areas in which the surface is divided. It discusses the mathematical formulation of the problem as well as some results obtained with the algorithms implemented in MATLAB and others obtained with the aid of MATLAB optimization routines. Finally, some examples and a convergence test are produced, comparing their analytical and numerical results. The final geometry of one of examples is verified by means of the soap film analogy, with a nonlinear equilibrium analysis through Ansys. The solutions have been sufficiently satisfactory, resulting forms very close to the analytical ones and with small areas relative errors. Convergence test also confirm that the method lead to numerical solutions as close to the analytical one as required, as long as the triangular facets mesh is refined. Therefore, the presented procedures can be used in structural membranes form finding.

This thesis presents a framework for understanding first-order theories by investigating their models. A common application is to help users, who are not necessarily experts in formal methods, analyze software artifacts, such as access-control policies, system configurations, protocol specifications, and software designs. The framework suggests a strategy for exploring the space of finite models of a theory via augmentation. Also, it introduces a notion of provenance information for understanding the elements and facts in models with respect to the statements of the theory. The primary mathematical tool is an information-preserving preorder, induced by the homomorphism on models, defining paths along which models are explored. The central algorithmic ideas consists of a controlled construction of the Herbrand base of the input theory followed by utilizing SMT-solving for generating models that are minimal under the homomorphism preorder. Our framework for model-exploration is realized in Razor, a model-finding assistant that provides the user with a read-eval-print loop for investigating models.

"We report the results of a series of crowd-sourced user studies in the formal-methods domain. Specifically, we explore the efficacy of the notion of "minimal counterexample" -- or more colloquially, "minimal bug report" -- when reasoning about logical specifications. Our results here suggest that minimal counterexamples are beneficial some specific cases, and harmful in others. Furthermore, our analysis leads to refined hypotheses about the role of minimal counterexamples that can be further evaluated in future studies. User-based evaluation has little precedent in the formal methods community. Therefore, as a further contribution, we discuss and analyze our research methodology, and offer guidelines for future user studies in formal methods research. "

A identificação de especialistas consiste na análise automática de informações sobre um conjunto de indivíduos para a localização daqueles com maior conhecimento em determinado tópico. Seus conhecimentos podem ser aplicados para a melhoria da produtividade em projetos de trabalho ou pesquisa e na localização de pesquisadores capacitados para avaliarem trabalhos de pesquisa ou para compor bancas de mestrado e doutorado. Para isso é interessante uma boa fonte de informações sobre os candidatos, de forma a otimizar o processo de identificação. No Brasil existe uma base de currículos que centraliza as informações sobre os pesquisadores brasileiros, a Plataforma Lattes. Os dados dessa plataforma são utilizados nesse trabalho para a realização da identificação de especialistas de acordo com suas áreas de atuação. São coletados dados da Plataforma e realizadas três etapas para compor uma lista ordenada dos principais especialistas de determinada área identificados pelo algoritmo proposto. A primeira etapa é a utilização da métrica TF-IDF, de modo que seus resultados são combinados com os estratos Qualis das publicações de cada autor, para finalmente ser aplicado um algoritmo de propagação para a geração da lista de especialistas. Após uma extensiva otimização dos parâmetros envolvidos no algoritmo, os resultados foram comparados com outra técnica existente que foi utilizada como base para esse projeto. Os resultados foram validados a partir de três conjuntos de pesquisadores coletados para esse projeto. O primeiro deles envolveu os pesquisadores contemplados com a Bolsa Produtividade em Pesquisa CNPq. Os resultados de dois questionários envolvendo pesquisadores das áreas de Inteligência Artificial e Nanotecnologia também foram utilizados. A partir dos resultados obtidos, foi possível notar que a técnica proposta aprimora significativamente os resultados do conjunto de Bolsistas Produtividade. Por outro lado, os resultados obtidos para os conjuntos de pesquisadores de Inteligência Artificial e Nanotecnologia foram ligeiramente melhores para a abordagem base. Os dados, algoritmos e resultados obtidos nesse trabalho poderão ser utilizados futuramente para aprimorar a identificação de especialistas / Expert finding consists in the automatic analysis of informations about a set of people with the objective of finding those with greater knowledge on a particular topic. His knowledge can be applied to improve the productivity in research and work projects and to locate researchers who are capable of evaluating research papers or for masters and doctoral degrees. For this objective it\'s interesting a good source of information about the candidates, in order to optimize the process of identification. In Brazil there\'s a curriculum base that centralizes the information about Brazilian researchers, the Lattes Plataform. It\'s data is used in this work to perform the expert finding according to the candidate\'s areas of activity. Data are collected from the Platform and three steps performed to generate a ordered list of the main specialists of a given area identified by the proposed algorithm. The first step is to use the TF-IDF metric, so that its results are combined with the Qualis strata from the publications of each author, to finally be applied a propagation algorithm for the generation of the specialists list. After an extensive optimization of the parameters involved in the algorithm, the results were compared with another technique that was used as the basis for this project. The results were validated from three sets of researchers collected for this project. The first one involved the researchers contemplated with the CNPq Productivity Grant. The results of two questionnaires involving researchers from the areas of Artificial Intelligence and Nanotechnology were also used. From the results obtained, it was noticeable that the proposed technique significantly improves the results of the Productivity Grant set. On the other hand, the results obtained for the Artificial Intelligence and Nanotechnology research groups were slightly better for the base approach. The data, algorithms and results obtained in this work may be used in the future to improve the expert finding

It is believed that structures and actuation systems should be tightly integrated together in the future to create fast moving, efficient, lightweight dynamic machines. Such actuated structures could be used for morphing aircraft wings, lightweight actuated space structures, or in robotics. This requires actuators to be distributed through the structure. A tensegrity structure is a very promising candidate for this future integration due to its potentially excellent stiffness and strength-to-weight ratio, and the inherent advantage of being a multi-element structure into which actuators can be embedded. Development of these machines will utilise expertise in several fields, involving kinematics, dynamics, actuation and multi-axis motion control. The research presented in this thesis concerns the study of multi-axis actuated tensegrity structures. A form-finding method has been developed to find stable geometries and determine stiffness properties of the type of tensegrity structure proposed. It has been shown that a tensegrity structure, with practical nodes of finite size, can be designed with actuated members to give shape-changing properties while potentially allowing a good stiffness to mass ratio. An antagonistic multi-axis control scheme has been developed for the tensegrity structure. The describing function technique has been used to analyse the dead band controller in the control scheme, giving a stability criterion. An experimental actuated tensegrity system has been designed and built incorporating pneumatic muscles controlled by switching valves. Mathematical models for the experimental actuated tensegrity system have been developed in detail, including the pneumatic actuation system and the structure geometry. The dynamic behaviour of the tensegrity system has been investigated via several simulation studies, using the developed models and the proposed control scheme. Experimental validation has been successfully conducted. The multi-axis control scheme can accurately control the tensegrity structure to achieve shape changes while maintaining a desired level of internal pre-load. The mathematical models can be used as a basis for further development.

A identificação de especialistas consiste na análise automática de informações sobre um conjunto de indivíduos para a localização daqueles com maior conhecimento em determinado tópico. Seus conhecimentos podem ser aplicados para a melhoria da produtividade em projetos de trabalho ou pesquisa e na localização de pesquisadores capacitados para avaliarem trabalhos de pesquisa ou para compor bancas de mestrado e doutorado. Para isso é interessante uma boa fonte de informações sobre os candidatos, de forma a otimizar o processo de identificação. No Brasil existe uma base de currículos que centraliza as informações sobre os pesquisadores brasileiros, a Plataforma Lattes. Os dados dessa plataforma são utilizados nesse trabalho para a realização da identificação de especialistas de acordo com suas áreas de atuação. São coletados dados da Plataforma e realizadas três etapas para compor uma lista ordenada dos principais especialistas de determinada área identificados pelo algoritmo proposto. A primeira etapa é a utilização da métrica TF-IDF, de modo que seus resultados são combinados com os estratos Qualis das publicações de cada autor, para finalmente ser aplicado um algoritmo de propagação para a geração da lista de especialistas. Após uma extensiva otimização dos parâmetros envolvidos no algoritmo, os resultados foram comparados com outra técnica existente que foi utilizada como base para esse projeto. Os resultados foram validados a partir de três conjuntos de pesquisadores coletados para esse projeto. O primeiro deles envolveu os pesquisadores contemplados com a Bolsa Produtividade em Pesquisa CNPq. Os resultados de dois questionários envolvendo pesquisadores das áreas de Inteligência Artificial e Nanotecnologia também foram utilizados. A partir dos resultados obtidos, foi possível notar que a técnica proposta aprimora significativamente os resultados do conjunto de Bolsistas Produtividade. Por outro lado, os resultados obtidos para os conjuntos de pesquisadores de Inteligência Artificial e Nanotecnologia foram ligeiramente melhores para a abordagem base. Os dados, algoritmos e resultados obtidos nesse trabalho poderão ser utilizados futuramente para aprimorar a identificação de especialistas / Expert finding consists in the automatic analysis of informations about a set of people with the objective of finding those with greater knowledge on a particular topic. His knowledge can be applied to improve the productivity in research and work projects and to locate researchers who are capable of evaluating research papers or for masters and doctoral degrees. For this objective it\'s interesting a good source of information about the candidates, in order to optimize the process of identification. In Brazil there\'s a curriculum base that centralizes the information about Brazilian researchers, the Lattes Plataform. It\'s data is used in this work to perform the expert finding according to the candidate\'s areas of activity. Data are collected from the Platform and three steps performed to generate a ordered list of the main specialists of a given area identified by the proposed algorithm. The first step is to use the TF-IDF metric, so that its results are combined with the Qualis strata from the publications of each author, to finally be applied a propagation algorithm for the generation of the specialists list. After an extensive optimization of the parameters involved in the algorithm, the results were compared with another technique that was used as the basis for this project. The results were validated from three sets of researchers collected for this project. The first one involved the researchers contemplated with the CNPq Productivity Grant. The results of two questionnaires involving researchers from the areas of Artificial Intelligence and Nanotechnology were also used. From the results obtained, it was noticeable that the proposed technique significantly improves the results of the Productivity Grant set. On the other hand, the results obtained for the Artificial Intelligence and Nanotechnology research groups were slightly better for the base approach. The data, algorithms and results obtained in this work may be used in the future to improve the expert finding

Phase I clinical trials in oncology aim to evaluate the toxicity risk of new therapies and identify a safe but also effective dose for future studies. Traditional Phase I trials of chemotherapies focus on estimating the maximum tolerated dose (MTD). The rationale for finding the MTD is that better therapeutic effects are expected at higher dose levels as long as the risk of severe toxicity is acceptable. With the advent of a new generation of cancer treatments such as the molecularly targeted agents (MTAs) and immunotherapies, higher dose levels no longer guarantee increased therapeutic effects, and the focus has shifted to estimating the optimal biological dose (OBD). The OBD is a dose level with the highest biologic activity with acceptable toxicity. The search for OBD requires joint evaluation of toxicity and efficacy. Although several seamleass phase I/II designs have been published in recent years, there is not a consensus regarding an optimal design and further improvement is needed for some designs to be widely used in practice. In this dissertation, we propose a modification to an existing seamless phase I/II design by Wages and Tait (2015) for locating the OBD based on binary outcomes, and extend it to time to event (TITE) endpoints. While the original design showed promising results, we hypothesized that performance could be improved by replacing the original adaptive randomization stage with a different randomization strategy. We proposed to calculate dose assigning probabilities by averaging all candidate models that fit the observed data reasonably well, as opposed to the original design that based all calculations on one best-fit model. We proposed three different strategies to select and average among candidate models, and simulations are used to compare the proposed strategies to the original design. Under most scenarios, one of the proposed strategies allocates more patients to the optimal dose while improving accuracy in selecting the final optimal dose without increasing the overall risk of toxicity. We further extend this design to TITE endpoints to address a potential issue of delayed outcomes. The original design is most appropriate when both toxicity and efficacy outcomes can be observed shortly after the treatment, but delayed outcomes are common, especially for efficacy endpoints. The motivating example for this TITE extension is a Phase I/II study evaluating optimal dosing of all-trans retinoic acid (ATRA) in combination with a fixed dose of daratumumab in the treatment of relapsed or refractory multiple myeloma. The toxicity endpoint is observed in one cycle of therapy (i.e., 4 weeks) while the efficacy endpoint is assessed after 8 weeks of treatment. The difference in endpoint observation windows causes logistical challenges in conducting the trial, since it is not acceptable in practice to wait until both outcomes for each participant have been observed before sequentially assigning the dose of a newly eligible participant. The result would be a delay in treatment for patients and undesirably long trial duration. To address this issue, we generalize the time-to-event continual reassessment method (TITE-CRM) to bivariate outcomes with potentially non-monotonic dose-efficacy relationship. Simulation studies show that the proposed TITE design maintains similar probability in selecting the correct OBD comparing to the binary original design, but the number of patients treated at the OBD decreases as the rate of enrollment increases. We also develop an R package for the proposed methods and document the R functions used in this research. The functions in this R package assist implementation of the proposed randomization strategy and design. The input and output format of these functions follow similar formatting of existing R packages such as "dfcrm" or "pocrm" to allow direct comparison of results. Input parameters include efficacy skeletons, prior distribution of any model parameters, escalation restrictions, design method, and observed data. Output includes recommended dose level for the next patient, MTD, estimated model parameters, and estimated probabilities of each set of skeletons. Simulation functions are included in this R package so that the proposed methods can be used to design a trial based on certain parameters and assess performance. Parameters of these scenarios include total sample size, true dose-toxicity relationship, true dose-efficacy relationship, patient recruit rate, delay in toxicity and efficacy responses.

This finding aid of interviews is drawn from the Arnold R. Hirsch Collection at the Amistad Research Center. Between 1987 and 1994, historian Arnold Hirsch interviewed New Orleans’ first black mayor, Ernest Morial, and others related to that crucial era in New Orleans political history. This collection consists of 37 audiocassettes tapes that contain oral history interviews conducted by Arnold Hirsch with various New Orleanians who were active in city government and political activism. This project-based thesis covers the research and construction of the finding aid completed for this collection during an internship at the Amistad Research Center, as well as the metadata collected and created for the collection. This collection and finding aid are being housed at the Amistad Research Center.

La mission Cassini, dédiée à l'étude de l'environnement de Saturne, comporte un récepteur radio (RPWS/HFR) couvrant la gamme 3.5 kHz-16 MHz, adaptée aux émissions radio de Saturne. La particularité de ce récepteur réside dans ces capacités goniopolarimétriques. En effet, malgré le fait que les dipôles qui lui sont connectées n'ont aucune résolution spatiale, on pourra retrouver la direction d'arrivée, le flux et l'état de polarisation de l'onde électromagnétique incidente. La partie instrumentale de mon travail a consisté d'une part à étalonner les antennes du récepteur et d'autre part, à développer des méthodes d'inversions goniopolarimétriques adaptées à ce type de récepteur. Une étude de la physique magnétosphérique de Jupiter a été entreprise. Nous avons obtenir, grâce à nos étalonnage, un nouveau spectre de référence des émissions radio jovienne dans la gamme du récepteur RPWS/HFR. Parmi toutes les émissions radio de la magnétosphère de Jupiter, j'ai choisi d'étudié plus particulièrement les sursauts quasi-périodiques seule composante jovienne dont on ne connaît pas l'origine. Les observations radio de Saturne ont débuté en janvier 2004 lors d'une campagne commune HST (téléscope spatial Hubble) Cassini. La caméra UV du HST a observé les aurores polaires de Saturne pendant que Cassini approchait la planète. Les observations HST sont comparées aux données radio, en terme de flux et de polarisation. Les résultats, préliminaires de cette étude sont en accord avec les résultats de Voyager. Enfin, je présente une proposition d'explication de la variabilité de la période apparente de rotation sidérale de Saturne mesurée grâce aux modulations des émissions radio.

Group delivered empirically supported therapies have been reported to have beneficial effects for cancer patients. However, little is known about the relationship between group cohesion and outcomes of these interventions. This study tested the hypothesis that group cohesion relates to the effects of a group intervention. Participants included 56 women with Stage I to II breast cancer who had completed a 10-week CBSM intervention 3 to 12 months after undergoing surgery and adjuvant therapy. Groups of 3 - 5 participants met weekly for sessions of approximately 1 hour and 45 minutes duration. All participants were assessed at baseline (2 weeks prior to beginning the intervention) and at follow-up (12 weeks after enrollment in the study). Cohesion was measured at the end of each intervention session by External Comfort (EC), a factor of the relatedness scale of the Stuttgarter Bogen instrument (1976). EC denotes an aspect of the sense of comfort of an individual within the group that is dependent on how the group participant relates to other members. EC score for session 9 (EC9), and change in EC from session 2 to session 9 (calculated as a change score, i.e., session 9 score minus session 2 score), were used for analyses as independent variables in simple linear regression models. Dependent variables were also calculated as a change score (i.e., follow-up minus baseline) and included benefit finding (Post Traumatic Growth Inventory PTGI, total score and its 5 factors), depression (CESD), urinary cortisol, and natural killer cell function (total percent, number and cytotoxicity). Results yielded a positive change in EC from session 2 to session 9 (M = 2.29, S.D. = 2.67). Regression analyses indicated a significant negative relationship between change in EC9 and change in total PTGI scores (beta= -.450, p= .011), and change in Factor 1 Relating to Others (beta=-.414, p=.021). A marginally significant negative relationship was observed between change in EC from session 2 to session 9 and the New Possibilities Factor of the PTGI (beta=-.323, p=.077). A median split, by change in EC, indicated that participants with high EC scores throughout the intervention showed an increase in total PTGI scores, and in two of the five PTGI factors at follow-up. In contrast, participants who initially scored lower values in EC showed no change in these variables. These results suggest that the longer it takes an individual to feel comfortable in the group, the less the individual would be able to find benefit from their cancer experience after the intervention.