909 resultados para String quartets


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SQL Injection Attack (SQLIA) remains a technique used by a computer network intruder to pilfer an organisation’s confidential data. This is done by an intruder re-crafting web form’s input and query strings used in web requests with malicious intent to compromise the security of an organisation’s confidential data stored at the back-end database. The database is the most valuable data source, and thus, intruders are unrelenting in constantly evolving new techniques to bypass the signature’s solutions currently provided in Web Application Firewalls (WAF) to mitigate SQLIA. There is therefore a need for an automated scalable methodology in the pre-processing of SQLIA features fit for a supervised learning model. However, obtaining a ready-made scalable dataset that is feature engineered with numerical attributes dataset items to train Artificial Neural Network (ANN) and Machine Leaning (ML) models is a known issue in applying artificial intelligence to effectively address ever evolving novel SQLIA signatures. This proposed approach applies numerical attributes encoding ontology to encode features (both legitimate web requests and SQLIA) to numerical data items as to extract scalable dataset for input to a supervised learning model in moving towards a ML SQLIA detection and prevention model. In numerical attributes encoding of features, the proposed model explores a hybrid of static and dynamic pattern matching by implementing a Non-Deterministic Finite Automaton (NFA). This combined with proxy and SQL parser Application Programming Interface (API) to intercept and parse web requests in transition to the back-end database. In developing a solution to address SQLIA, this model allows processed web requests at the proxy deemed to contain injected query string to be excluded from reaching the target back-end database. This paper is intended for evaluating the performance metrics of a dataset obtained by numerical encoding of features ontology in Microsoft Azure Machine Learning (MAML) studio using Two-Class Support Vector Machines (TCSVM) binary classifier. This methodology then forms the subject of the empirical evaluation.

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Target space duality is one of the most profound properties of string theory. However it customarily requires that the background fields satisfy certain invariance conditions in order to perform it consistently; for instance the vector fields along the directions that T-duality is performed have to generate isometries. In the present paper we examine in detail the possibility to perform T-duality along non-isometric directions. In particular, based on a recent work of Kotov and Strobl, we study gauged 2D sigma models where gauge invariance for an extended set of gauge transformations imposes weaker constraints than in the standard case, notably the corresponding vector fields are not Killing. This formulation enables us to follow a procedure analogous to the derivation of the Buscher rules and obtain two dual models, by integrating out once the Lagrange multipliers and once the gauge fields. We show that this construction indeed works in non-trivial cases by examining an explicit class of examples based on step 2 nilmanifolds.

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We present a generalization of the complete intersection in products of projective space (CICY) construction of Calabi–Yau manifolds. CICY three-folds and four-folds have been studied extensively in the physics literature. Their utility stems from the fact that they can be simply described in terms of a ‘configuration matrix’, a matrix of integers from which many of the details of the geometries can be easily extracted. The generalization we present is to allow negative integers in the configuration matrices which were previously taken to have positive semi-definite entries. This broadening of the complete intersection construction leads to a larger class of Calabi–Yau manifolds than that considered in previous work, which nevertheless enjoys much of the same degree of calculational control. These new Calabi–Yau manifolds are complete intersections in (not necessarily Fano) ambient spaces with an effective anticanonical class. We find examples with topology distinct from any that has appeared in the literature to date. The new manifolds thus obtained have many interesting features. For example, they can have smaller Hodge numbers than ordinary CICYs and lead to many examples with elliptic and K3-fibration structures relevant to F-theory and string dualities.

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We construct parent Hamiltonians involving only local 2-body interactions for a broad class of projected entangled pair states (PEPS). Making use of perturbation gadget techniques, we define a perturbative Hamiltonian acting on the virtual PEPS space with a finite order low energy effective Hamiltonian that is a gapped, frustration-free parent Hamiltonian for an encoded version of a desired PEPS. For topologically ordered PEPS, the ground space of the low energy effective Hamiltonian is shown to be in the same phase as the desired state to all orders of perturbation theory. An encoded parent Hamiltonian for the double semion string net ground state is explicitly constructed as a concrete example.

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A sociedade em que vivemos hoje encontra-se submersa pela tecnologia em todas as áreas e saberes, exigindo-se aos cidadãos a capacidade de pensar e agir racionalmente perante os desafios e problemas que vão surgindo ao longo da vida. As tecnologias da informação e comunicação (TIC) são uma presença evidente no quotidiano e diversas investigações e estudos têm vindo a enfatizar o seu potencial no processo de ensino-aprendizagem. Ademais, face aos desafios científicos e tecnológicos da nossa sociedade, é fundamental formar-se cidadãos capazes de pensar criticamente e racionalmente, de tomarem decisões focadas no que se deve fazer ou acreditar. Assim, reconhecendo a importância de se promover o pensamento crítico (PC) recorrendo-se às TIC, desenvolveu-se a presente investigação com o intuito de promover o PC dos alunos, através da exploração de diversos recursos digitais já disponíveis gratuitamente na internet. Decorrente da finalidade apresentada formularam-se as seguintes questões de estudo: (i) Quais os contributos dos recursos digitais explicitamente promotores de pensamento crítico dos alunos do 3.º ano de escolaridade?; e (ii) Quais os contributos dos recursos digitais explicitamente promotores de pensamento crítico para a construção de conhecimentos científicos, na área das Ciências, dos alunos do 3.º ano de escolaridade?. A presente investigação desenvolveu-se de acordo com um paradigma sócio-crítico, segundo uma perspetiva metodológica predominantemente qualitativa e com base num plano de Investigação-Ação. A implementação das três atividades construídas, incluindo a exploração dos recursos digitais, decorreu numa turma de 26 alunos inseridos num colégio do distrito de Aveiro, no qual se realizou a Prática Pedagógica Supervisionada da professora investigadora. Para a recolha dos dados utilizaram-se diversos instrumentos, nomeadamente testes de levantamento inicial e final das capacidades de PC, listas de verificação, diário do investigador, fichas de trabalho resolvidas pelos alunos (tendo por base a Taxonomia de Ennis) e questionários de autoavaliação do desempenho dos mesmos. Na análise de dados, privilegiou-se a análise de conteúdo recorrendo-se ao software WebQDA. Com base nos instrumentos de recolha de dados referidos verificou-se que os alunos manifestaram uma maior facilidade a responder a questões que promoviam o uso de capacidades de PC referentes à Clarificação Elementar e à Indução e uma dificuldade acentuada na dimensão das Estratégias e Táticas. No que diz respeito à construção de conhecimentos científicos, os alunos demonstraram, principalmente, dificuldades em reconhecer que o movimento é impulsionado pelas rodas dentadas e a constatar que o tamanho do fio influencia a velocidade do pêndulo. Pode-se concluir que os recursos digitais, de um modo geral, contribuíram para mobilizar o potencial de capacidades de PC e para a construção de conhecimentos científicos. O contributo deste estudo, embora modesto, prende-se com o potencial das TIC na Educação em Ciências dos 1º CEB, na promoção do pensamento crítico e de conhecimentos.

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The purpose of this dissertation is to produce a new Harmonie arrangement of Mozart’s Die Zauberflöte suitable for modern performance, bringing Joseph Heidenreich’s 1782 arrangement—one of the great treasures of the wind repertoire—to life for future performers and audiences. I took advantage of the capabilities of modern wind instruments and performance techniques, and employed other instruments normally found in the modern wind ensemble to create a work in the tradition of Heidenreich’s that restored as much of Mozart’s original thinking as possible. I expanded the Harmonie band to include flute and string bass. Other instruments provide special effects, a traditional role for wind instruments in the Classical opera orchestra. This arrangement is conceived to be performed with the original vocal soloists, making it a viable option for concert performance or for smaller staged productions. It is also intended to allow the wind players to be onstage with the singers, becoming part of the dramatic action while simultaneously serving as the “opera orchestra.” This allows creative staging possibilities, and offers the wind players an opportunity to explore new aspects of performing. My arrangement also restores Mozart’s music to its original keys and retains much of his original wind scoring. This arrangement expands the possibilities for collaboration between opera studios, voice departments or community opera companies and wind ensembles. A suite for winds without voices (currently in production) will allow conductors to program this major work from the Classical era without dedicating a concert program to the complete opera. Excerpted arias and duets from this arrangement provide vocalists the option of using chamber wind accompaniment on recitals. The door is now open to arrangements of other operas by composers such as Mozart, Rossini and Weber, adding new repertoire for chamber winds and bringing great music to life in a new way.

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Schedules can be built in a similar way to a human scheduler by using a set of rules that involve domain knowledge. This paper presents an Estimation of Distribution Algorithm (EDA) for the nurse scheduling problem, which involves choosing a suitable scheduling rule from a set for the assignment of each nurse. Unlike previous work that used Genetic Algorithms (GAs) to implement implicit learning, the learning in the proposed algorithm is explicit, i.e. we identify and mix building blocks directly. The EDA is applied to implement such explicit learning by building a Bayesian network of the joint distribution of solutions. The conditional probability of each variable in the network is computed according to an initial set of promising solutions. Subsequently, each new instance for each variable is generated by using the corresponding conditional probabilities, until all variables have been generated, i.e. in our case, a new rule string has been obtained. Another set of rule strings will be generated in this way, some of which will replace previous strings based on fitness selection. If stopping conditions are not met, the conditional probabilities for all nodes in the Bayesian network are updated again using the current set of promising rule strings. Computational results from 52 real data instances demonstrate the success of this approach. It is also suggested that the learning mechanism in the proposed approach might be suitable for other scheduling problems.

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Abstract- A Bayesian optimization algorithm for the nurse scheduling problem is presented, which involves choosing a suitable scheduling rule from a set for each nurse's assignment. Unlike our previous work that used GAs to implement implicit learning, the learning in the proposed algorithm is explicit, i.e. eventually, we will be able to identify and mix building blocks directly. The Bayesian optimization algorithm is applied to implement such explicit learning by building a Bayesian network of the joint distribution of solutions. The conditional probability of each variable in the network is computed according to an initial set of promising solutions. Subsequently, each new instance for each variable is generated by using the corresponding conditional probabilities, until all variables have been generated, i.e. in our case, a new rule string has been obtained. Another set of rule strings will be generated in this way, some of which will replace previous strings based on fitness selection. If stopping conditions are not met, the conditional probabilities for all nodes in the Bayesian network are updated again using the current set of promising rule strings. Computational results from 52 real data instances demonstrate the success of this approach. It is also suggested that the learning mechanism in the proposed approach might be suitable for other scheduling problems.

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Schedules can be built in a similar way to a human scheduler by using a set of rules that involve domain knowledge. This paper presents an Estimation of Distribution Algorithm (EDA) for the nurse scheduling problem, which involves choosing a suitable scheduling rule from a set for the assignment of each nurse. Unlike previous work that used Genetic Algorithms (GAs) to implement implicit learning, the learning in the proposed algorithm is explicit, i.e. we identify and mix building blocks directly. The EDA is applied to implement such explicit learning by building a Bayesian network of the joint distribution of solutions. The conditional probability of each variable in the network is computed according to an initial set of promising solutions. Subsequently, each new instance for each variable is generated by using the corresponding conditional probabilities, until all variables have been generated, i.e. in our case, a new rule string has been obtained. Another set of rule strings will be generated in this way, some of which will replace previous strings based on fitness selection. If stopping conditions are not met, the conditional probabilities for all nodes in the Bayesian network are updated again using the current set of promising rule strings. Computational results from 52 real data instances demonstrate the success of this approach. It is also suggested that the learning mechanism in the proposed approach might be suitable for other scheduling problems.

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Uma transcrição musical consiste numa composição adaptada de uma obra original para outra instrumentação, que não a inicialmente definida pelo compositor. Nestas, o conteúdo original tende a permanecer o mais fiel possível (De Vente, 2005). A partir do século XIX esta prática tornou-se corrente e prolífica. Atualmente, o uso de transcrições é bastante comum, especialmente quando destinado a instrumentos musicais com uma história recente devido à sua falta de repertório canónico. Um instrumento característico deste último grupo é o saxofone para o qual se tem transcrito uma grande quantidade de obras com especial ênfase nos períodos barroco e romântico. Nesta monografia detalho uma abordagem metodológica à transcrição musical que visa expandir o repertório para saxofone para além dos períodos barroco e romântico, assim como instrumentações e desafios diversos no processo de adaptação tais como: adaptar obras polifónicas para um instrumento monofónico, transcrever gestos técnicos e específicos de um instrumento de corda e criar continuidades sonoras típicas do uso do pedal no piano no saxofone. O processo de transcrição descrito nesta monografia impõe uma metamorfose timbrica às obras originais e oferece ao ouvinte uma perspectiva diferente sobre o conteúdo musical assim como questiona conceitos de autenticidade e autoria. Quatro composições que seguem a atual proposta de transcrição são apresentadas e documentadas. De ressaltar a diversidade de escolhas do repertório transcrito em termos de estilo, e instrumentação que se traduzem num grande desafio na adaptação ao saxofone, entre estas: Dream, John Cage, Chaccone em Sol menor, Tomaso Vitali, Fratres, Arvo Pärt e o Inverno das Quatro Estações, Antonio Vivaldi.

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Visant à contribuer à la pérennité de la musique d’art instrumentale, cette thèse aborde plusieurs sujets la concernant, autant sur les plans théorique et esthétique que pratique et compositionnel. Les deux principaux contextes observés sont ceux de la modernité et de l’économie de marché. Le premier, par le triomphe de la raison technicienne, aurait conduit à l’autonomie de l’art désormais confronté aux risques de l’autoréférence. Le deuxième, par la pression exercée sur le compositeur à la base de la chaîne création-production-diffusion, compromettrait cette autonomie qu’elle avait pourtant contribuée à rendre possible. Or, l’autonomie de l’art, en tant que conquête sur les plans esthétique, social, politique, économique et intellectuel, représente un enjeu de taille, puisque d’éventuelles compromissions envers des impératifs extérieurs impliquent un recul sur tous ces plans. Pour répondre à cette problématique, la thèse explore des pistes de réflexions et d’opérations pour réaffirmer – en le revendiquant – ce que la musique d’art possède en propre et qui mérite encore d’être entendu, militant ainsi pour la survie de ce qui la rend possible. Plus précisément, la dialectique du son et de la musique que je développe ici me permet, dans un premier temps, d’aborder les médiations successives conduisant des ondes mécaniques à se structurer dans notre conscience jusqu’à se transmettre à nous sous forme de patrimoine; puis, dans un deuxième temps, de décrire ma propre intention de communication par la musique en analysant deux œuvres de ma composition : Musique d’art pour quintette à cordes et Musique d’art pour orchestre de chambre II (partie 1.). Musique d’art pour quintette à cordes est une œuvre-concert de soixante-cinq minutes pour quatuor à cordes et contrebasse, spatialisation, traitement et mise en espace des musiciens. Il s’agit d’un projet de recherche-création de mon initiative que j’ai aussi mené à titre de producteur. Musique d’art pour orchestre de chambre II (partie 1.) est une œuvre de commande de quatorze minutes. Le retour critique portant sur l’ensemble des composantes caractéristiques du média ouvre la voie à une corrélation plus étroite entre son contenu et sa forme privilégiée de présentation, le concert. Cette corrélation peut amener le public à désirer visiter les œuvres et apprécier leur signification, préservant la musique d’art comme mode spécifique de connaissance du monde.

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Instrumental or vocal teaching in music schools and general music education in compulsory schools represents primary elements of German music education. Both directions are combined on a professional basis by string, wind, singing or band classes. Music pedagogical theories describing instrumental teaching and school music, respectively, have evolved differently in the past - a fact that is scarcely addressed in the literature. In this article both problem-centered interview and video-assisted thought- reconstruction techniques are employed to use differences in the corresponding theories for building empirically grounded explanations of string classes. Major findings indicate that the instrumental teacher's background in traditional teaching structures strongly influences the realization of certain characteristics of aesthetic practice. (DIPF/Orig.)

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Human mesenchymal stem cells (MSC) are powerful sources for cell therapy in regenerative medicine. The long time cultivation can result in replicative senescence or can be related to the emergence of chromosomal alterations responsible for the acquisition of tumorigenesis features in vitro. In this study, for the first time, the expression profile of MSC with a paracentric chromosomal inversion (MSC/inv) was compared to normal karyotype (MSC/n) in early and late passages. Furthermore, we compared the transcriptome of each MSC in early passages with late passages. MSC used in this study were obtained from the umbilical vein of three donors, two MSC/n and one MSC/inv. After their cryopreservation, they have been expanded in vitro until reached senescence. Total RNA was extracted using the RNeasy mini kit (Qiagen) and marked with the GeneChip ® 3 IVT Express Kit (Affymetrix Inc.). Subsequently, the fragmented aRNA was hybridized on the microarranjo Affymetrix Human Genome U133 Plus 2.0 arrays (Affymetrix Inc.). The statistical analysis of differential gene expression was performed between groups MSC by the Partek Genomic Suite software, version 6.4 (Partek Inc.). Was considered statistically significant differences in expression to p-value Bonferroni correction ˂.01. Only signals with fold change ˃ 3.0 were included in the list of differentially expressed. Differences in gene expression data obtained from microarrays were confirmed by Real Time RT-PCR. For the interpretation of biological expression data were used: IPA (Ingenuity Systems) for analysis enrichment functions, the STRING 9.0 for construction of network interactions; Cytoscape 2.8 to the network visualization and analysis bottlenecks with the aid of the GraphPad Prism 5.0 software. BiNGO Cytoscape pluggin was used to access overrepresentation of Gene Ontology categories in Biological Networks. The comparison between senescent and young at each group of MSC has shown that there is a difference in the expression parttern, being higher in the senescent MSC/inv group. The results also showed difference in expression profiles between the MSC/inv versus MSC/n, being greater when they are senescent. New networks were identified for genes related to the response of two of MSC over cultivation time. Were also identified genes that can coordinate functional categories over represented at networks, such as CXCL12, SFRP1, xvi EGF, SPP1, MMP1 e THBS1. The biological interpretation of these data suggests that the population of MSC/inv has different constitutional characteristics, related to their potential for differentiation, proliferation and response to stimuli, responsible for a distinct process of replicative senescence in MSC/inv compared to MSC/n. The genes identified in this study are candidates for biomarkers of cellular senescence in MSC, but their functional relevance in this process should be evaluated in additional in vitro and/or in vivo assays

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A Bayesian optimization algorithm for the nurse scheduling problem is presented, which involves choosing a suitable scheduling rule from a set for each nurse’s assignment. Unlike our previous work that used GAs to implement implicit learning, the learning in the proposed algorithm is explicit, i.e. eventually, we will be able to identify and mix building blocks directly. The Bayesian optimization algorithm is applied to implement such explicit learning by building a Bayesian network of the joint distribution of solutions. The conditional probability of each variable in the network is computed according to an initial set of promising solutions. Subsequently, each new instance for each variable is generated by using the corresponding conditional probabilities, until all variables have been generated, i.e. in our case, a new rule string has been obtained. Another set of rule strings will be generated in this way, some of which will replace previous strings based on fitness selection. If stopping conditions are not met, the conditional probabilities for all nodes in the Bayesian network are updated again using the current set of promising rule strings. Computational results from 52 real data instances demonstrate the success of this approach. It is also suggested that the learning mechanism in the proposed approach might be suitable for other scheduling problems.

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Slender rotating structures are used in many mechanical systems. These structures can suffer from undesired vibrations that can affect the components and safety of a system. Furthermore, since some these structures can operate in a harsh environment, installation and operation of sensors that are needed for closed-loop and collocated control schemes may not be feasible. Hence, the need for an open-loop non-collocated scheme for control of the dynamics of these structures. In this work, the effects of drive speed modulation on the dynamics of slender rotating structures are studied. Slender rotating structures are a type of mechanical rotating structures, whose length to diameter ratio is large. For these structures, the torsion mode natural frequencies can be low. In particular, for isotropic structures, the first few torsion mode frequencies can be of the same order as the first few bending mode frequencies. These situations can be conducive for energy transfer amongst bending and torsion modes. Scenarios with torsional vibrations experienced by rotating structures with continuous rotor-stator contact occur in many rotating mechanical systems. Drill strings used in the oil and gas industry are an example of rotating structures whose torsional vibrations can be deleterious to the components of the drilling system. As a novel approach to mitigate undesired vibrations, the effects of adding a sinusoidal excitation to the rotation speed of a drill string are studied. A portion of the drill string located within a borewell is considered and this rotating structure has been modeled as an extended Jeffcott rotor and a sinusoidal excitation has been added to the drive speed of the rotor. After constructing a three-degree-of-freedom model to capture lateral and torsional motions, the equations of motions are reduced to a single differential equation governing torsional vibrations during continuous stator contact. An approximate solution has been obtained by making use of the Method of Direct Partition of Motions with the governing torsional equation of motion. The results showed that for a rotor undergoing forward or backward whirling, the addition of sinusoidal excitation to the drive speed can cause an increase in the equivalent torsional stiffness, smooth the discontinuous friction force at contact, and reduce the regions of negative slope in the friction coefficient variation with respect to speed. Experiments with a scaled drill string apparatus have also been conducted and the experimental results show good agreement with the numerical results obtained from the developed models. These findings suggest that the extended Jeffcott rotordynamics model can be useful for studies of rotor dynamics in situations with continuous rotor-stator contact. Furthermore, the results obtained suggest that the drive speed modulation scheme can have value for attenuating drill-string vibrations.