Portfolios and the market geometry

A geometric analysis of the time series of returns has been performed in the past and it implied that the most of the systematic information of the market is contained in a space of small dimension. Here we have explored subspaces of this space to find out the relative performance of portfolios formed from the companies that have the largest projections in each one of the subspaces. It was found that the best performance portfolios are associated to some of the small eigenvalue subspaces and not to the dominant directions in the distances matrix. This occurs in such a systematic fashion over an extended period (1990-2008) that it may not be a statistical accident.Comment: 13 pages 12 figure

Feminismos y reapropiación del discurso en el hacer radio.

Ddentro de los cambios promovidos por las tecnologías de la información y de la comunicación, la transmisión en línea de las radios y el advenimiento de los podcasts ha posibilitado una mayor apertura del espacio radiofónico, hecho que ha favorecido los colectivos alejados de las esferas institucionales y que tienen como foco la comunicación. En diversas radios libres, grupos de mujeres optan por promover una contrainformación desde los feminismos, dando protagonismo a experiencias cotidianas individuales y colectivas y promoviendo la difusión y creación de discursos que pretenden ser una alternativa al discurso heteropatriarcal hegemónico. La experiencia feminista compartida se asume aquí como una intersección entre la investigación académica y la militancia. De forma que se repiensan las relaciones de poder y la relación entre discurso y poder a través de las micropolíticas y de cómo éstas, a través de prácticas cotidianas y colectivas, generan discursos alternativos e inciden en cambios de consciencia

Hacia una crítica feminista de la sociedad red: más allá de la revolución de la audiencia creativa

La relación entre discursos y poder implica relaciones de género y se enmarca, principalmente, en el ámbito de la comunicación, por ser ésta el escenario por donde fluyen los discursos y, por tanto, donde están representadas las relaciones de poder. Un entramado que considero susceptible de deconstrucción desde una toma de conciencia crítica feminista. El presente artículo parte de la apuesta por los conocimientos situados (Haraway, 1995; Castañeda Salgado, 2008) como la opción epistemológica adecuada para una investigación crítica, asumiendo la experiencia feminista como un campo de intersección entre la investigación académica y la militancia. Tomando la sociedad informacional (Castells, 2000) como el actual paradigma de organización social y abordando conceptos como la sociedad red y la autocomunicación de masas (Castells, 2009), pretendo cuestionar cuáles son límites de los cambios tecnológicos del actual contexto comunicacional. Busco poner en debate la plasticidad de las TICs y del nuevo panorama de la comunicación, tratando, aparte de sus potencialidades, factores que comúnmente son invisibilizados ante el entusiasmo por una posible democratización de los medios, como pueden ser las reproducciones de violencias machistas y de discursos heteropatriarcales disciplinarios. The relation between discourse and power involves gender relations and it should be addressed in the field of communications, since this is the arena where discourses mainly flow and, therefore, wherepowerrelationsarerepresented.Ascheme I consider capable of deconstruction from a feminist critical awareness. This article assumes situated knowledge (Haraway, 1995; Castañeda Salgado, 2008) as the appropriate epistemological choice for a critical investigation, assuming feminist experience as a field of intersection between academic research and militancy. Taking the informational society (Castells, 2000) as the current paradigm of social organization and using concepts such as the network society and mass self-communication (Castells, 2009), in this article, I intend to question what are the limits of the current communicational technological changes. Hoping to discuss the plasticity of the new communications scenario and ICTs and considering, besides their potentialities, factors that are often invisible because of the enthusiasm provoked by a possible democratization of media, such as reproduction of sexist violence and heteropatriarchy disciplinary discourses.

Notas para a unidade curricular Tópicos de Matemática Discreta - mestrado integrado em Engenharia Informática

Texto de apoio às aulas teóricas da UC Tópicos de MAtemática Discreta do curso de Mestrado Integrado em Engenharia Informática.info:eu-repo/semantics/draf

Injective linear transformations with equal gap and defect

Suppose V is an infinite-dimensional vector space over a field F and let I(V) denote the inverse semigroup of all injective partial linear transformations on V. Given ß in I(V), we denote the domain and the range of ß by dom ß and im ß, respectively, and we call the cardinals g(ß)=codim(domß) and d(ß)=codim(imß) the `gap' and the `defect' of ß, respectively. In this paper, we study the semigroup A(V) of all injective partial linear transformations with equal gap and defect, and characterise Green's relations and ideals in A(V). This is analogous to work by Sanwong and Sullivan in 2009 on a similarly-defined semigroup for the set case, but we show that these semigroups are never isomorphic.The research of the authors was partially financed by Portuguese Funds through FCT (Fundação para a Ciência e a Tecnologia) within the Projects UIDB/00013/2020 and UIDP/00013/2020

Leather inspection and characterization using non-destructive techniques

Leather is a widely used component of many products such as shoes, car seats, garments and other leather goods. Because it is a natural material, a tanned hide will contain visual and hidden flaws. In addition, its mechanical properties vary over the hide. At present, hides are inspected and assessed by skilled operatives. Further, current objective leather testing requires removal of samples and is either destructive and/or incompatible with real time operation, and little or no information about the rest of the skin is provided.A novel mechanical scanning system was built for non-destructive leather testing. The investigation was focused on two of the most important physical leather properties, static compressibility across thickness and tensile properties for low strain regions. The results of static compression energy measurements for a compressive strain of 10 percent, showed a close agreement with the results of tests performed by a conventional compressibility tester. Further, the results of strain energy and stress measurements for a strain of 2 percent, revealed a very good correlation with the results of conventional tensile tests for a similar strain.The application of infrared thermography, a non destructive and contact less technique, to leather characterisation and inspection was investigated in this work. It was shown that this technique could be used for detecting defects in leather, as well as for estimating their size and deepness. However, defect visibility by infrared thermography is conditioned by the fact that a defective area has to cause different material properties or produce an internal thermal resistance. Further, the prohibitive cost of infrared thermography cameras for automation is a serious limitation for its application in current leather testing. It is recommended that the ideal testing system would be based on the combination of mechanical scanning, normal computer vision and infrared thermography. The normal computer vision part of this system would be responsible for measuring area and detecting defects that are visible in nature. The infrared thermography part of the system would be responsible for detecting the type of defects overlooked by the previous method, as well as some thermo-physical parameters. Finally, the Mechanical Scanning System would provide the physical properties of leather, like compressibility, tensile modulus, shear stress and softness that the vision based inspection systems are incapable of providing. In this way, every single skin could be completely characterised in terms of defects and physical properties

Cadavre Exquis: motion-controlled interactive film

This interactive film, a variation on the surrealist game Cadavre Exquis, seeks the possibility of subverting the filmic discourse by exploring psychosomatic processes that may give the viewer different perceptions of cinematic time, by providing the possibility of intervening into the narrative in a disruptive way.info:eu-repo/semantics/publishedVersio

Tecnologias para rastreabilidade de processos na indústria naval : o caso de estudo dos estaleiros West Sea Viana Shipyard

Mestrado em Engenharia Informática na Escola Superior de Tecnologia e Gestão do Instituto Politécnico de Viana do CasteloTraceability of materials and elements in any type of industry is essential and of great value although it is currently gaining even more importance due to the factories of Industry 5.0. This is important in the context of the manufacture of any product This allows the user to know the origin of a particular element, whether it is a raw material or a component made of other previously manufactured elements. This chain of traceable information can be persisted by several technologies, one of which is the blockchain. This concept of traceability is applied in any type of industry in some way, but sometimes there are more appropriate methods that can even add value to the final product Therefore, this process enables the tracking of products components throughout the chain of production, from raw materials to the final product, passing through each intermediate component and process stage, on every industrial player in the chain. The information generated through the manufacturing process, including certificates and inspection results, is registered and thus trackable. In the shipbuilding industry, the process of building a ship is complex, has several stages, and it is important to guarantee high-quality levels during the manufacturing process. For this, the methods and technologies adopted for process traceability must be selected, having in mind the specific requirements and constraints of the shipbuilding industry in the most efficient way. In addition, process traceability may add value to the ship, as all the traceable information may be easily transferred to the end customer. This way, the customer can have the information of any material, component, part, and block of the ship easily and reliably, as well as all the certificates and documents necessary for any process. This thesis proposes a blockchain-centered system architecture that fosters the traceability of the production processes applied to the shipbuilding industry, based on the West Sea Viana Shipyard. The system will be implemented as a case study in the manufacturing process of a shipbuilding block, and therefore readily extendable to the overall ship manufacturing process, thus contributing with a blockchain containing or referring to all relevant documents (certificates, warranties, etc.) and other pertinent manufacturing data that can be delivered to the customer together with the ship, and thus increasing trustability.A rastreabilidade de materiais e elementos em qualquer tipo de indústria é essencial e de grande valor, embora atualmente esteja a ganhar ainda mais importância devido às fábricas da Indústria 5.0. Isto é importante no contexto do fabrico de qualquer produto, isto porque, permite que o utilizador conheça a origem de um determinado produto, seja uma matéria-prima ou um componente fabricado através outros elementos, posteriormente fabricados. Esta cadeia de informações rastreáveis pode ser mantida através de várias tecnologias, uma das quais é o 'blockchain'. Este conceito de rastreabilidade é aplicado em qualquer tipo de indústria de alguma forma, mas por vezes existem métodos mais adequados que podem até acrescentar valor ao produto final. Portanto, este processo permite a rastreabilidade dos componentes de produtos em toda a cadeia de fabrico, desde a matéria-prima até o produto final, passando por cada componente intermediário e etapa do processo, em todos os participantes industriais da cadeia de fabrico. As informações geradas durante o processo de fabrico, incluindo certificados e resultados de inspeção. também são registadas e, portanto, rastreáveis. Na indústria naval, é essencial garantir altos níveis de qualidade durante o processo de fabrico. Para isso, é importante selecionar os métodos e tecnologias adequados para a rastreabilidade dos processos, considerando as exigências e restrições específicas da indústria naval. Desta forma, o cliente pode ter as informações de qualquer material, componente, peça e bloco do navio de forma simples e confiável. A rastreabilidade do processo pode acrescentar valor ao navio, pois todas as informações rastreáveis podem ser facilmente transferidas para o cliente final, incluindo todos os certificados e documentos necessários. Nesta tese é proposta uma arquitetura de sistema cerrada em tecnologia blockchain que promove a rastreabilidade dos processos de produção aplicados à indústria naval, com base no Estaleiro West Sea Viana. O sistema será implementado como um caso de estudo no processo de fabrico de um bloco de construção naval e, portanto, prontamente extensível ao processo geral de fabrico de navios, contribuindo assim com uma 'blockchain' contendo ou referindo-se a todos os documentos relevantes (certificados, garantias, etc.) e outros dados de fabrico pertinentes que podem ser entregues ao cliente junto com o navio, aumentando assim a confiabilidade. Além disto, é também feita a implementação de duas provas de conceito de interfaces visuais, tudo isto é testado com informação proveniente do Estaleiro West Sea Viana e validado pelos mesmos