Convex Quadratic Programming Approach to the Maximum Matching Problem

The problem of determining a maximum matching or whether there exists a perfect matching, is very common in a large variety of applications and as been extensively studied in graph theory. In this paper we start to introduce a characterisation of a family of graphs for which its stability number is determined by convex quadratic programming. The main results connected with the recognition of this family of graphs are also introduced. It follows a necessary and sufficient condition which characterise a graph with a perfect matching and an algorithmic strategy, based on the determination of the stability number of line graphs, by convex quadratic programming, applied to the determination of a perfect matching. A numerical example for the recognition of graphs with a perfect matching is described. Finally, the above algorithmic strategy is extended to the determination of a maximum matching of an arbitrary graph and some related results are presented.

Functional analysis of String/CDC25 phosphatase in post-mitotic neurons

Cell cycle and differentiation are two highly coordinated processes during organ development. Recent studies have demonstrated that core cell cycle regulators also play cell cycle-independent functions in post-mitotic neurons, and are essential for the maintenance of neuronal homeostasis. CDC25 phosphatases are well-established CDK activators and their activity is mainly associated to proliferating tissues. The expression and activity of mammalian CDC25s has been reported in adult brains. However, their physiological relevance and the potential substrates in a non-proliferative context have never been addressed. string (stg) encodes the Drosophila CDC25 homolog. Previous studies from our group showed that stg is expressed in photoreceptors (PRs) and in lamina neurons, which are two differentiated cell types that compose the fly visual system. The aims of this work are to uncover the function of stg and to identify its potential neuronal substrates, using the Drosophila visual system as a model. To gain insight into the function of stg in a non-dividing context we used the GAL4/UAS system to promote downregulation of stg in PR-neurons, through the use of an RNAi transgene. The defects caused by stg loss-of-function were evaluated in the developing eye imaginal disc by immunofluorescence, and during adult stages by scanning electron microscopy. This genetic approach was combined with a specific proteomic method, two-dimensional difference gel electrophoresis (2D-DIGE), to identify the potential substrates in PR-cells. Our results showed that stg downregulation in PRs affects the well-patterned retina organization, inducing the loss of apical maintenance of PR-nuclei on the eye disc, and ommatidia disorganization. We also detected an abnormal accumulation of cytoskeletal proteins and a disruption of the axon structure. As a consequence, the projection of PR-axons into the lamina and medulla neuropils of the optic lobe was impaired. Upon stg downregulation, we also detected that PR-cells accumulate Cyclin B. Although the rough eye phenotype observed upon stg downregulation suggests neurodegeneration, we did not detect neuronal death during larval stages, suggesting that it likely occurs during pupal stages or during adulthood. By 2D-DIGE, we identified seven proteins which were differentially expressed upon stg downregulation, and are potential neuronal substrates of Stg. Altogether, our observations suggest that Stg phosphatase plays an essential role in the Drosophila visual system neurons, regulating several cell components and processes in order to ensure their homeostasis.

Face matching impairment in developmental prosopagnosia

Developmental prosopagnosia (DP) is commonly referred to as ‘face blindness’, a term that implies a perceptual basis to the condition. However, DP presents as a deficit in face recognition and is diagnosed using memory-based tasks. Here, we test face identification ability in six people with DP, who are severely impaired on face memory tasks, using tasks that do not rely on memory. First, we compared DP to control participants on a standardised test of unfamiliar face matching using facial images taken on the same day and under standardised studio conditions (Glasgow Face Matching Test; GFMT). DP participants did not differ from normative accuracy scores on the GFMT. Second, we tested face matching performance on a test created using images that were sourced from the Internet and so vary substantially due to changes in viewing conditions and in a person’s appearance (Local Heroes Test; LHT). DP participants show significantly poorer matching accuracy on the LHT relative to control participants, for both unfamiliar and familiar face matching. Interestingly, this deficit is specific to ‘match’ trials, suggesting that people with DP may have particular difficulty in matching images of the same person that contain natural day-to-day variations in appearance. We discuss these results in the broader context of individual differences in face matching ability.

Face recogniton based on the optimal combination of neural networks, eigenfaces and least squares matching methods

Report of a research project of the Fachhochschule Hannover, University of Applied Sciences and Arts, Department of Information Technologies. Automatic face recognition increases the security standards at public places and border checkpoints. The picture inside the identification documents could widely differ from the face, that is scanned under random lighting conditions and for unknown poses. The paper describes an optimal combination of three key algorithms of object recognition, that are able to perform in real time. The camera scan is processed by a recurrent neural network, by a Eigenfaces (PCA) method and by a least squares matching algorithm. Several examples demonstrate the achieved robustness and high recognition rate.

Erstellung wiederverwendbarer RDF-Geodaten mit Google Refine

Das Forschungsinformationssystem VIVO bietet als Linked-Data-basiertes System die Möglichkeit, Daten aus anderen Quellen wiederzuverwenden. In der Praxis kann man dabei auf Konvertierungsprobleme stoßen. Oft liegen Daten nur in tabellarischem Format vor, z.B. als CSV-Datei. Zur Konvertierung dieser Daten existieren verschiedene Werkzeuge, viele dieser Werkzeuge erfordern jedoch entweder spezielle technische Umgebungen (oft Linux-Systeme) oder sie sind in der Bedienung sehr anspruchsvoll. Im Artikel wird ein Workflow für die Konvertierung von Daten aus GeoNames für VIVO mit Google Refine beschrieben.

O software Google Sketchup como instrumento no ensino da geometria descritiva

Relatório da Prática de Ensino Supervisionada, Ensino de Artes Visuais, Universidade de Lisboa, 2013

The Philadelphia String Quartet, January 8, 1971

Concert program for The Philadelphia String Quartet, January 8, 1971

The sound of a breaking string: critical environmental law and ontological vulnerability

This is a thought-provoking contribution on the space of ontological vulnerability as the awareness of being existentially exposed. This space, conceptualised as a space of ‘the middle’ (as opposed, emphatically, to ‘the centre’) offers an opportunity to think away from the sterile debate on eco/anthropocentricity and from such limiting hierarchies as animal/human, human/environmental, natural/artificial. This new, vulnerable position of the middle allows the reconfiguration of ecological processes, and more specifically the position of environmental law in relation to them. Environmental law now finds itself amidst a new, moving, ‘open ecology’ of social, biological and ecological processes. This is a new, radical conceptualisation of what the author has called ‘critical environmental law,’ based upon an epistemology of observation and an ontology of being part of this open ecology. Environmental law, in this light, is simultaneously reformulated as an invitation to disciplinary and ontological openness and yet a call to remain immanent within existing legal structures. This finds expression in four critical environmental positions that set the stage for the further elaboration of a critical environmental law.

The Philadelphia String Quartet November 19, 1971

Concert program for Philadelphia String Quartet, Nov. 19, 1971

Philadelphia String Quartet October 29, 1971

Concert Program for Philadelphia String Quartet, Oct. 29, 1971

The Philadelphia String Quartet July 13, 1971

Concert program for The Philadelphia String Quartet, July 13, 1971

SecGOD - Google Docs: Now I Feel Safer!

This paper presents SecGOD. A tool that protects the privacy of documents created with online office suites. SecGOD is implemented as a Greasemonkey java-script making it deployable on all popular greesemonkey compatible browsers and utilizes symmetric key encryption. All operations run on the client side, with SecGOD operating invisibly as concerned by the cloud, with no changes needed to the code that is provided to the cloud server provider. Finally, the effectiveness of SecGOD is demonstrated by conducting extensive experiments measuring the processing time for the three versions of AES (128, 192, 256 bits).

Behavioural development in a matching-to-sample task and token use by an infant chimpanzee reared by his mother

Animal Cognition, V.6, pp. 259–267

Otimização do sítio web e google adwords

Relatório de estágio apresentado ao Instituto de Contabilidade e Administração do Porto para a obtenção do grau de Mestre em Empreendedorismo e Internacionalização, sob orientação de Doutora Ana Azevedo.

Enhancing Agent Mediated Electronic Markets with Ontology Matching Services and Social Network Support

Os Mercados Eletrónicos atingiram uma complexidade e nível de sofisticação tão elevados, que tornaram inadequados os modelos de software convencionais. Estes mercados são caracterizados por serem abertos, dinâmicos e competitivos, e constituídos por várias entidades independentes e heterogéneas. Tais entidades desempenham os seus papéis de forma autónoma, seguindo os seus objetivos, reagindo às ocorrências do ambiente em que se inserem e interagindo umas com as outras. Esta realidade levou a que existisse por parte da comunidade científica um especial interesse no estudo da negociação automática executada por agentes de software [Zhang et al., 2011]. No entanto, a diversidade dos atores envolvidos pode levar à existência de diferentes conceptualizações das suas necessidades e capacidades dando origem a incompatibilidades semânticas, que podem prejudicar a negociação e impedir a ocorrência de transações que satisfaçam as partes envolvidas. Os novos mercados devem, assim, possuir mecanismos que lhes permitam exibir novas capacidades, nomeadamente a capacidade de auxiliar na comunicação entre os diferentes agentes. Pelo que, é defendido neste trabalho que os mercados devem oferecer serviços de ontologias que permitam facilitar a interoperabilidade entre os agentes. No entanto, os humanos tendem a ser relutantes em aceitar a conceptualização de outros, a não ser que sejam convencidos de que poderão conseguir um bom negócio. Neste contexto, a aplicação e exploração de relações capturadas em redes sociais pode resultar no estabelecimento de relações de confiança entre vendedores e consumidores, e ao mesmo tempo, conduzir a um aumento da eficiência da negociação e consequentemente na satisfação das partes envolvidas. O sistema AEMOS é uma plataforma de comércio eletrónico baseada em agentes que inclui serviços de ontologias, mais especificamente, serviços de alinhamento de ontologias, incluindo a recomendação de possíveis alinhamentos entre as ontologias dos parceiros de negociação. Este sistema inclui também uma componente baseada numa rede social, que é construída aplicando técnicas de análise de redes socias sobre informação recolhida pelo mercado, e que permite melhorar a recomendação de alinhamentos e auxiliar os agentes na sua escolha. Neste trabalho são apresentados o desenvolvimento e implementação do sistema AEMOS, mais concretamente: • É proposto um novo modelo para comércio eletrónico baseado em agentes que disponibiliza serviços de ontologias; • Adicionalmente propõem-se o uso de redes sociais emergentes para captar e explorar informação sobre relações entre os diferentes parceiros de negócio; • É definida e implementada uma componente de serviços de ontologias que é capaz de: • o Sugerir alinhamentos entre ontologias para pares de agentes; • o Traduzir mensagens escritas de acordo com uma ontologia em mensagens escritas de acordo com outra, utilizando alinhamentos previamente aprovados; • o Melhorar os seus próprios serviços recorrendo às funcionalidades disponibilizadas pela componente de redes sociais; • É definida e implementada uma componente de redes sociais que: • o É capaz de construir e gerir um grafo de relações de proximidade entre agentes, e de relações de adequação de alinhamentos a agentes, tendo em conta os perfis, comportamento e interação dos agentes, bem como a cobertura e utilização dos alinhamentos; • o Explora e adapta técnicas e algoritmos de análise de redes sociais às várias fases dos processos do mercado eletrónico. A implementação e experimentação do modelo proposto demonstra como a colaboração entre os diferentes agentes pode ser vantajosa na melhoria do desempenho do sistema e como a inclusão e combinação de serviços de ontologias e redes sociais se reflete na eficiência da negociação de transações e na dinâmica do mercado como um todo.