Non-algebraic Examples of Manifolds with the Volume Density Property

Some Stein manifolds (with a volume form) have a large group of (volume-preserving) automorphisms: this is formalized by the (volume) density property, which has remarkable consequences. Until now all known manifolds with the volume density property are algebraic, and the tools used to establish this property are algebraic in nature. In this note we adapt a known criterion to the holomorphic case, and give the first known examples of non-algebraic manifolds with the volume density property: they arise as suspensions or pseudo-affine modifications over Stein manifolds satisfying some technical properties. As an application we show that there are such manifolds that are potential counterexamples to the Zariski Cancellation Problem, a variant of the Toth-Varolin conjecture, and the problem of linearization of C*-actions on C^3

Backward stochastic differential equation approach to modeling of gene expression

In this article, we introduce a novel backward method to model stochastic gene expression and protein level dynamics. The protein amount is regarded as a diffusion process and is described by a backward stochastic differential equation (BSDE). Unlike many other SDE techniques proposed in the literature, the BSDE method is backward in time; that is, instead of initial conditions it requires the specification of endpoint ("final") conditions, in addition to the model parametrization. To validate our approach we employ Gillespie's stochastic simulation algorithm (SSA) to generate (forward) benchmark data, according to predefined gene network models. Numerical simulations show that the BSDE method is able to correctly infer the protein level distributions that preceded a known final condition, obtained originally from the forward SSA. This makes the BSDE method a powerful systems biology tool for time reversed simulations, allowing, for example, the assessment of the biological conditions (e.g. protein concentrations) that preceded an experimentally measured event of interest (e.g. mitosis, apoptosis, etc.).Comment: Accepted in Physical Review

Visual Memories of the marble industry: Using Cinema and Photography in Mining Heritage Studies

The introduction of new techniques and technological equipment into the Portuguese marble industry led to an exponential increase in production and, consequently, to profound environmental and landscape changes. The fact that the techniques had previously been adopted in other marble mining regions, like Wallonia (Belgium) and Carrara (Italy), confirms the standardization of the extraction and transformation process. However, despite using the same technology, each region’s local know-how and landscape features gave rise to different working contexts, many of which are not documented in written sources. Indeed, moving images and iconography prove to be a relevant source for studying local working techniques, machinery adaptations, or work distributions. Visual sources can be used to update previous studies and produce new ones, such as comparisons between quarrying techniques. Furthermore, these images prove to be a suitable and appealing educational instrument to show how technology has changed to allow firms to overcome market challenges and quarry vast mineral deposits

Sistemas Não Cooperativos para Registo de Assiduidade em Ambiente de Sala de Aula

Over the years, high school dropout, college dropout, in particular, has always been a hot topic. With the advancement of technology and Artificial Intelligence and Machine Learning, we necessarily have to think of ways to help mitigate this problem. If there are factors that we cannot control, such as the economic ones, there are others where our actions can be directed. One factor that allows us to evaluate the risk of dropping out of school is student attendance. Although this data can be manually analyzed to make these detections, it would be more efficient to have a capable system of recording this attendance, since the human capacity to analyze data is finite, and often can only infer this situation too late. Of course, a system that only registers attendance will not give a definitive answer, but it will be an essential first step. Thus, a system that can reconcile the detection of a subject and his face while being able to constantly monitor where the subject is, always to be able to identify him even if he moves from one place to another, together with facial recognition, seem to be determining factors to bring a system of this calibre to a successful conclusion. This type of system is generally very much related to the quality of the data and its annotations, so it is vital to collect or obtain quality data to help solve the various problems presented. Considering what has been described, the main goal of this dissertation is to try to start solving the problem of school dropout, namely through the study, validation and testing of several state­of­the­art methods in the area of object detection, namely people and faces, but also tracking. The same work will have to be done on face recognition methods, being able to indicate the best state­of­the­art methods for each task. As mentioned in the previous paragraph, a significant limitation to this type of task is the data quality since it is not always possible to find a set that perfectly fits our context. Thus, to solve this gap, we will also present a dataset with about 40,000 images, thoroughly annotated frame by frame and that we believe to be an asset in solving this problem. In addition to the above, and in order not only to give a more meaningful and targeted response to our detailed data but also to provide a preliminary view of how one of the system’s tasks might work, we will present two experiments with our data in the area of detection. The first will involve finetuning our data, while the second will involve training it from scratch and then presenting its results as proof of the correct choice of the state­of­the­art method.Ao longo dos anos, o abandono escolar, o universitário em particular, tem sido sempre um tema em grande destaque. Com o avanço de várias áreas tecnológicas, assim como da Inteligência Artificial e da Aprendizagem Automática temos necessariamente de pensar em maneiras de ajudar a mitigar este problema. Se há fatores que não podemos controlar, como os económicos, há outros onde a nossa ação pode ser dirigida. Um dos fatores que permite avaliar o risco de abandono escolar é a assiduidade dos estudantes. Embora, naturalmente, estes dados possam ser analisados manualmente para fazer estas deteções, seria mais eficiente ter um sistema que fosse capaz de registar esta assiduidade, uma vez que a capacidade humana para os analisar é finita e muitas vezes apenas consegue inferir esta situação demasiado tarde. Naturalmente que um sistema que registe apenas assiduidade não irá ser capaz de dar uma resposta definitiva, mas será um primeiro passe importante. Deste modo, um sistema que seja capaz de conciliar a deteção de uma pessoa e da sua face enquanto é capaz de monitorizar de forma constante o sítio onde a pessoa está, para ser sempre capaz de a identificar mesmo que mude de sítio em conjunto com o seu reconhecimento facial, parecem ser fatores determinantes para levar a bom porto um sistema deste calibre. Este tipo de sistemas está, geralmente, muito relacionado com a qualidade dos dados e das suas anotações, pelo que é extraordinariamente importante ser capaz de recolher ou obter dados de qualidade que auxiliem na resolução dos diversos problemas apresentados. Tendo em atenção aquilo que foi sendo descrito, o principal objetivo desta dissertação passa por tentar dar início à resolução do problema do abandono escolar, nomeadamente através do estudo, validação e teste de diversos métodos estado­da­arte no que diz respeito à área da deteção de objetos, nomeadamente de pessoas e faces, mas também de tracking. O mesmo trabalho terá de ser realizado nos métodos de reconhecimento facial, sendo capaz no final de poder indicar os melhores métodos estado­da­arte de cada tarefa. Como referido no parágrafo anterior, uma limitação grande a este tipo de tarefas é a respetiva qualidade dos dados, visto que nem sempre e possível encontrar um conjunto que se adeque perfeitamente ao nosso contexto. Assim, de modo a solucionar esta lacuna iremos também apresentar um dataset com cerca de 40,000 imagens, completamente anotado frame a frame e que acreditamos ser uma mais valia na resolução deste problema. Para além do referido, e de modo não só a dar uma resposta mais significativa e dirigida aos nossos dados em particular, mas também para que seja possível ter uma visão preliminar daquilo que poderá ser o funcionamento de uma das tarefas do sistema, iremos apresentar duas experiências com os nossos dados, na área da deteção. A primeira irá envolver o finetuning dos nossos dados, enquanto que a segunda levará a um treino iniciado de raiz, apresentando depois os seus resultados como uma prova da escolha acertada do método de estado da arte

CORQ - Code Review for Quality Measurement

Trabalho de Projeto de Mestrado, Informática, 2022, Universidade de Lisboa, Faculdade de CiênciasThis report was developed based on the project held in the portuguese software company Opensoft in the context of my Master’s degree in Computer Science from September 6th 2021 to June 30th 2022. Quality and productivity are some of, if not the most important factors in any software company in today’s reality for its growth and operation. Therefore, there is a need to obtain quality and productivity metrics for the work conducted by software developers. Code Review for Quality Measurement (as will be referenced from now on as CORQ) is a tool developed from scratch by a small team in Opensoft including me, which is the software company where this tool was developed, for the purpose of this thesis, that provides metrics on the productivity and quality of software of a company’s employees, projects, or itself overall. The tool may only be used in Opensoft initially due to the interfaces that are used to obtain these metrics and the specifications needed to implement the project. This problem can be solved with future work, in case we want to expand the tool so it is usable in other software companies. CORQ intends to use multiple interfaces such as SonarQube, Jira, Confluence, Git repositories in Bitbucket and SVN repositories to obtain information about Opensoft’s artifacts and thus calculates metrics on the productivity and quality of its employees and the software produced by them. With the use of CORQ it is expected for the company’s employees to be more motivated, increasing their productivity, saving human resources, and saving analysis time spent on the software produced. CORQ can be used complementary to code reviewing and other software quality assurance techniques and software

ESTRATÉGIAS GENÉRICAS DE COMPETIÇÃO PRATICADAS POR IES PRIVADAS DE PEQUENO PORTE

A partir do mapeamento da cadeia de valor genérica para o segmento de ensino superior e de uma pequena amostra de avaliações institucionais, baseadas no sistema SINAES (Sistema Nacional de Avaliação do Ensino Superior, proposto pelo Ministério da Educação), realizadas entre os anos de 2009 e 2010, este artigo identifica e discute estratégias desenvolvidas por IES Privadas de pequeno porte para sustentar uma posição competitiva no mercado Brasileiro, caracterizado atualmente por ser altamente competitivo, por serviços de commodity e com uma demanda decrescente e retraída. Para tanto, foi desenvolvido um estudo empírico e exploratório, com abordagem qualitativa, utilizando-se o método de estudos multicasos. As estratégias competitivas identificadas, seus resultados positivos e limitações sevem para indicar horizontes e possibilitar reflexões sobre a adoção de algumas práticas de gestão em IES privadas