934 resultados para Symbolic and Algebraic Manipulation


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Thèse réalisée en cotutelle avec l'Ecole des Hautes Etudes en Sciences Sociales (Paris)

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n the recent years protection of information in digital form is becoming more important. Image and video encryption has applications in various fields including Internet communications, multimedia systems, medical imaging, Tele-medicine and military communications. During storage as well as in transmission, the multimedia information is being exposed to unauthorized entities unless otherwise adequate security measures are built around the information system. There are many kinds of security threats during the transmission of vital classified information through insecure communication channels. Various encryption schemes are available today to deal with information security issues. Data encryption is widely used to protect sensitive data against the security threat in the form of “attack on confidentiality”. Secure transmission of information through insecure communication channels also requires encryption at the sending side and decryption at the receiving side. Encryption of large text message and image takes time before they can be transmitted, causing considerable delay in successive transmission of information in real-time. In order to minimize the latency, efficient encryption algorithms are needed. An encryption procedure with adequate security and high throughput is sought in multimedia encryption applications. Traditional symmetric key block ciphers like Data Encryption Standard (DES), Advanced Encryption Standard (AES) and Escrowed Encryption Standard (EES) are not efficient when the data size is large. With the availability of fast computing tools and communication networks at relatively lower costs today, these encryption standards appear to be not as fast as one would like. High throughput encryption and decryption are becoming increasingly important in the area of high-speed networking. Fast encryption algorithms are needed in these days for high-speed secure communication of multimedia data. It has been shown that public key algorithms are not a substitute for symmetric-key algorithms. Public key algorithms are slow, whereas symmetric key algorithms generally run much faster. Also, public key systems are vulnerable to chosen plaintext attack. In this research work, a fast symmetric key encryption scheme, entitled “Matrix Array Symmetric Key (MASK) encryption” based on matrix and array manipulations has been conceived and developed. Fast conversion has been achieved with the use of matrix table look-up substitution, array based transposition and circular shift operations that are performed in the algorithm. MASK encryption is a new concept in symmetric key cryptography. It employs matrix and array manipulation technique using secret information and data values. It is a block cipher operated on plain text message (or image) blocks of 128 bits using a secret key of size 128 bits producing cipher text message (or cipher image) blocks of the same size. This cipher has two advantages over traditional ciphers. First, the encryption and decryption procedures are much simpler, and consequently, much faster. Second, the key avalanche effect produced in the ciphertext output is better than that of AES.

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A new localization approach to increase the navigational capabilities and object manipulation of autonomous mobile robots, based on an encoded infrared sheet of light beacon system, which provides position errors smaller than 0.02m is presented in this paper. To achieve this minimal position error, a resolution enhancement technique has been developed by utilising an inbuilt odometric/optical flow sensor information. This system respects strong low cost constraints by using an innovative assembly for the digitally encoded infrared transmitter. For better guidance of mobile robot vehicles, an online traffic signalling capability is also incorporated. Other added features are its less computational complexity and online localization capability all these without any estimation uncertainty. The constructional details, experimental results and computational methodologies of the system are also described

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In recent years, researchers in artificial intelligence have become interested in replicating human physical reasoning talents in computers. One of the most important skills in this area is predicting how physical systems will behave. This thesis discusses an implemented program that generates algebraic descriptions of how systems of rigid bodies evolve over time. Discussion about the design of this program identifies a physical reasoning paradigm and knowledge representation approach based on mathematical model construction and algebraic reasoning. This paradigm offers several advantages over methods that have become popular in the field, and seems promising for reasoning about a wide variety of classical mechanics problems.

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Desde el abordaje de la arte-terapia y de la espiritualidad, es posible hallar la relación que ambos conceptos entrañan, relacionado con el significado simbólico y universal que el arte (a través de todas su manifestaciones), puede brindar al espíritu para alcanzar su transformación (personal y transpersonal), sea ésta comprendida desde un marco de intervención en patología o en disfuncionalidad, así como desde el marco de promoción en salud, teniendo en cuenta el carácter holístico de todo ser humano. ¿Qué tiene el arte que "cura" a los pacientes? Mediante una revisión de la literatura que tiene en cuenta las características específicas de la intersección de estos dos campos, tales como la relación terapéutica, el acto creativo, los niveles transpersonales del desarrollo y la imaginación, se aborda este interrogante.

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Este artículo indaga por las dificultades en la protección de los derechos de las mujeres indígenas desplazadas, en el contexto de la pluralidad jurídica de que son sujetas y de la eficacia simbólica que comportan estos múltiples ordenamientos para ellas. Con base enla observación participante realizada por el autor, se sostiene que las relaciones entre la pluralidad interna y externa de los ordenamientos jurídicos, así como la eficacia simbólica, privilegian los intereses de los hombres y el Estado, y generan la desprotección de las mujeres indígenas desplazadas a través de fenómenos específicos. En la primera parte, se examinanlas dificultades internas y externas de los ordenamientos nacional e internacional y su eficacia simbólica, las cuales no permiten desarrollar los derechos de las mujeres indígenas desplazadasde forma específica y diferenciada. En la segunda parte, se analizan los argumentos locales que, desde el punto de vista de las mujeres indígenas, dificultan las reclamaciones de sus derechos. Finalmente, se observan tres fenómenos específicos de desprotección de las mujeres indígenas desplazadas.

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l artículo explora el contenido de la idea de Europa, con el objetivo de mostrar que no está definida por la “identidad” como un resultado producto de la historia, la geografía, o los aspectos económicos, sino por un conjunto de factores, en parte aleatorios, que la han ido constituyendo a través del tiempo. La aproximación cultural (en este caso histórico-antropológica) a las características de lo europeo se efectúa comenzando con la misma idea de Europa, que se analiza desde sus comienzos como el resultado de una amalgama de culturas como la cretense, la fenicia y la egipcia, con el aporte y el discurso que al respecto han tenido los griegos, los romanos, las tentativas de unidad europea desde Carlo Magno y Carlos V, hasta la Unión Europea de nuestros días.El estudio de las estructuras simbólicas e históricas que han construido una idea de lo europeo ha sido multiforme y no siempre idéntico. Además, concluye la autora, no puede definirse a Europa en términos de una ‘identidad’ fija que sea necesario proteger a toda costa frente a intrusiones culturales externas. Por el contrario, se trata de un proceso o ‘configuración’ sociohistórica que permite que en futuras ampliaciones países que por su pasado no podrían aspirar a ser miembros de la Unión Europea, pueden llegar a serlo por su futuro; tal es el caso en especial de Turquía y Ucrania.-----This article explores the idea of Europe in order to show that it is defined not by “identity” as a result or product of history, geography or economic factors, but by a set of partially random factors that have gradually shaped the idea over time. The cultural approach to Europe’s characteristics (in this case historical-anthropological) starts by analyzing the idea of Europe from its origins as an amalgam of Cretan, Phoenician, Egyptian and other cultures, which later absorbed Greek and Roman contributions and thinking, followed by the attempts by Charlemagne and Charles V to unify Europe, and culminating in the modernday European Union. The symbolic and historical structures that have shaped the idea of Europe have taken a variety of different forms. Furthermore, the author concludes that Europe cannot be defined in terms of a fixed “identity” that must be protected from external cultural interference at all costs. On the contrary, it is a socio-historical process or “configuration” which, in future enlargements, will allow countries that formerly could not aspire to become members of the European Union to become future members. This applies especially to Turkey and the Ukraine.

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Generalmente se asocia los Estados modernos con la separación entre política y religión, la objetivación del poder y la elección racional, dejando de lado lo simbólico y lo identitario. La existencia del Estado de Israel es un ejemplo paradójico de una democracia fundamentada en el judaísmo, que ignora el principio de las minorías que habitan en dicho territorio, producto de la historia de la colonización de Palestina lo que ha acarreado conflictos internos y con los países vecinos. Ante los constantes fracasos por dirimir el conflicto, esta disertación otorga una relevancia superior al papel que pueden desempeñar la religión, los símbolos y estudia las funciones que cumplen las instituciones religiosas con el objetivo de establecer si la construcción del Estado abrahámico puede poner fin a la disputa entre dos pueblos hermanos, motivada por controlar una Tierra Prometida.

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El trabajo pretende brindar una aproximación crítica analítica a aquella propositiva histórica familiar dentro de la extensa literatura sobre los orígenes de la Guerra Fría. Reconociendo de antemano que el escenario de la Guerra Fría no fue necesariamente el efecto de una amenaza inminente.

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RESUMO: Objetivo - apresentar o contributo da Escola Mãe Hilda para a afirmação da identidade afro-brasileira na população estudantil da Cidade do Salvador. Especificamente: a) conhecer os fundamentos pedagógicos-curricular da Escola Mãe Hilda; b) analisar os materiais didáticos utilizados pela Escola Mãe Hilda; c) apresentar as metodologias de trabalho da Escola Mãe Hilda. Metodologia - quanto ao percurso metodológico, em razão da questão básica desta dissertação, optou-se por realizar pesquisa qualitativa de natureza etnográfica, envolvendo uma abordagem empírica voltada para a abordagem de distúrbios identitários, em suas diversas dimensões na auto-estima de afro-descendentes. Foram estudados aspectos que envolvem o currículo, a sala de aula e atividades a que estão expostas as crianças da Escola Mãe Hilda. Resultados - examinando- se os conteúdos dos Cadernos de Educação do Ilê Aiyê como proposta pedagógica da Escola Mãe Hilda, observou- se que seus fudamentos dão ressignificação aos alunos, em termos de superação de distúrbios identitários, isto é , proporcionar o desenvolvimento e construção da identidade negra naqueles afro-descendentes, devido à valorização estética do universo cultural africano e afro-brasileiro, reconhecendo a África como uma das matrizes legítimas da cultura humana, em geral, e da brasileira, em particular. Conclusão- a pedagogia da (re) construção da identidade negra na Escola Mãe Hilda pode contribuir para a desconstrução dos distúrbios identitários; sendo assim, recomendada para escolas em Salvador-Bahia e em outras regiões do Brasil. ABSTRACT: Objective- study Escola Mãe Hilda (EMH - Mother Hilda School) contribution to the affirmation of an African-Brazilian identity in Bahia’s black student population. In particular: a) understand EMH’s pedagogical and curricula core; b) analyze teaching materials used at EMH; c) show EMH’s work methodology. Methodology- due to the very nature of this dissertation’s basic inquiry, ethnography in nature qualitative research targeted at identity disturbances in its various dimensions regarding African descendents self-esteem was performed. Aspects regarding EMH curriculum and classroom activities were studied. The choice of ethnography as an observation tool followed empirical analysis of whether Ilê Aiyê’s Educational Booklets as adopted by EMH aids students with identity disturbances and how it promotes the development of a black identity in those black descendants. Results- it has been observed that EMH utilizes methodological and pedagogical resources such as: story-telling, written reports, images, objects, dances, music, letters, myths, gestures, legends, craftsmanship, and clothing as vehicles to re-assign students self esteem, as well as, build their critical and self-aware knowledge of black descendants identity. Conclusion.- EMH pedagogical work, by encompassing various types of cultural and artistic expressions, as detailed in the aforementioned booklets, values African and Brazilian-African references. This aesthetic valuation therefore promotes an identity ressignification and the reintegration of the black descendent since it works within the symbolic and cultural universe of the African and African-Brazilian culture recognizing Africa as a legitimate matrix of human culture, in general, and of Brazilian in particular. Conclusively, EMH black identity (re)construction pedagogy can contribute to deconstruct identity disturbances; and as such, can be recommended to be adopted at other schools in Salvador, Bahia and other regions in Brazil.

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Severe acute respiratory syndrome (SARS) coronavirus infection and growth are dependent on initiating signaling and enzyme actions upon viral entry into the host cell. Proteins packaged during virus assembly may subsequently form the first line of attack and host manipulation upon infection. A complete characterization of virion components is therefore important to understanding the dynamics of early stages of infection. Mass spectrometry and kinase profiling techniques identified nearly 200 incorporated host and viral proteins. We used published interaction data to identify hubs of connectivity with potential significance for virion formation. Surprisingly, the hub with the most potential connections was not the viral M protein but the nonstructurall protein 3 (nsp3), which is one of the novel virion components identified by mass spectrometry. Based on new experimental data and a bioinformatics analysis across the Coronaviridae, we propose a higher-resolution functional domain architecture for nsp3 that determines the interaction capacity of this protein. Using recombinant protein domains expressed in Escherichia coli, we identified two additional RNA-binding domains of nsp3. One of these domains is located within the previously described SARS-unique domain, and there is a nucleic acid chaperone-like domain located immediately downstream of the papain-like proteinase domain. We also identified a novel cysteine-coordinated metal ion-binding domain. Analyses of interdomain interactions and provisional functional annotation of the remaining, so-far-uncharacterized domains are presented. Overall, the ensemble of data surveyed here paint a more complete picture of nsp3 as a conserved component of the viral protein processing machinery, which is intimately associated with viral RNA in its role as a virion component.

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This paper describes a study that was conducted to learn more about how older adults use the tools in a GUI to undertake tasks in Windows applications. The objective was to gain insight into what people did and what they found most difficult. File and folder manipulation, and some aspects of formatting presented difficulties, and these were thought to be related to a lack of understanding of the task model, the correct interpretation of the visual cues presented by the interface, and the recall and translation of the task model into a suitable sequence of actions.

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A polynomial-based ARMA model, when posed in a state-space framework can be regarded in many different ways. In this paper two particular state-space forms of the ARMA model are considered, and although both are canonical in structure they differ in respect of the mode in which disturbances are fed into the state and output equations. For both forms a solution is found to the optimal discrete-time observer problem and algebraic connections between the two optimal observers are shown. The purpose of the paper is to highlight the fact that the optimal observer obtained from the first state-space form, commonly known as the innovations form, is not that employed in an optimal controller, in the minimum-output variance sense, whereas the optimal observer obtained from the second form is. Hence the second form is a much more appropriate state-space description to use for controller design, particularly when employed in self-tuning control schemes.

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Neurofuzzy modelling systems combine fuzzy logic with quantitative artificial neural networks via a concept of fuzzification by using a fuzzy membership function usually based on B-splines and algebraic operators for inference, etc. The paper introduces a neurofuzzy model construction algorithm using Bezier-Bernstein polynomial functions as basis functions. The new network maintains most of the properties of the B-spline expansion based neurofuzzy system, such as the non-negativity of the basis functions, and unity of support but with the additional advantages of structural parsimony and Delaunay input space partitioning, avoiding the inherent computational problems of lattice networks. This new modelling network is based on the idea that an input vector can be mapped into barycentric co-ordinates with respect to a set of predetermined knots as vertices of a polygon (a set of tiled Delaunay triangles) over the input space. The network is expressed as the Bezier-Bernstein polynomial function of barycentric co-ordinates of the input vector. An inverse de Casteljau procedure using backpropagation is developed to obtain the input vector's barycentric co-ordinates that form the basis functions. Extension of the Bezier-Bernstein neurofuzzy algorithm to n-dimensional inputs is discussed followed by numerical examples to demonstrate the effectiveness of this new data based modelling approach.