Submitted by André Ynada dos Santos (andre.ynada@gmail.com) on 2018-06-15T19:32:21Z No. of bitstreams: 1 André Ynada dos santos _ dissertacao _ final (4) impressão.pdf: 1375963 bytes, checksum: 58cfc6a13ec9745a09db5dc67982ca28 (MD5) / Approved for entry into archive by Satie Tagara (satie@marilia.unesp.br) on 2018-06-18T13:25:49Z (GMT) No. of bitstreams: 1 santos_ay_me_mar.pdf: 1375963 bytes, checksum: 58cfc6a13ec9745a09db5dc67982ca28 (MD5) / Made available in DSpace on 2018-06-18T13:25:49Z (GMT). No. of bitstreams: 1 santos_ay_me_mar.pdf: 1375963 bytes, checksum: 58cfc6a13ec9745a09db5dc67982ca28 (MD5) Previous issue date: 2018-05-18 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Considerando a crescente importância da imagem como elemento de informação, o que pressupõe o desenvolvimento de abordagens cada vez mais acuradas de organização e de representação, no presente trabalho busca-se identificar as formas pelas quais a organização e representação da informação imagética tem sido discutida no âmbito da International Society for Knowledge Organization (ISKO) com o objetivo de verificar quais são os referenciais e as tendências teóricas da análise e da representação da imagem no universo da organização do conhecimento em nível internacional. Para tanto, será analisada a literatura científica oficial da ISKO por meio dos anais dos congressos internacionais e da revista Knowledge Organization, entre os anos de 1990 a 2015. Nesse sentido, serão selecionados os artigos que apresentem o(s) termo(s) image*, picture*, photo*, film*, movie* no título e/ou no resumo, a partir do que se procederá à análise de domínio, a partir das abordagens bibliométrica e epistemológica propostas por Hjørland (2002). / Considering the increasing importance of image as an element of information, which presuposes the development of increasingly accurate approaches to organization and representation, the present work aims to identify the ways in which the organization and representation of imagery information has been discussed in the International Society for Knowledge Organization (ISKO) with the objective of verifying the theoretical references and trends of image analysis and representation in the universe of knowledge organization at the international level. In order to achieve this, the official scientific literature of the ISKO is analyzed including the proceedings of the international conferences and the Knowledge Organization journal, from 1990 to 2015. In this sense, I analyzed the articles that present the term (s) image *, picture *, photo *, film *, movie * in the title and/or abstract using domain analysis in the bibliometric and epistemological approaches proposed by Hjørland (2002).

Made available in DSpace on 2014-06-11T19:27:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-09-17Bitstream added on 2014-06-13T20:17:14Z : No. of bitstreams: 1 danuello_jc_me_mar.pdf: 457859 bytes, checksum: 7e83188d6cee5941a099a6722ecc8873 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / Com o objetivo de caracterizar a produção científica docente da área de Tratamento Temático da Informação – T.T.I. foram selecionados 77 artigos de periódicos de autoria de 19 docentes de pós-graduação atuantes na área, buscando detectar as características dessa produção e das fontes de informação utilizadas pelos docentes-autores que possam oferecer um conhecimento mais amplo da área enquanto espaço de atuação acadêmica. Com os dados extraídos desses artigos, foi montada uma base de dados contendo os seguintes campos: autor, título do artigo, título da publicação, palavras-chave, citações, país, idioma e ano da publicação e instituição do autor. Para trabalhar os dados, foi utilizado o software VantagePoint que organiza a informação permitindo a geração de listas e matrizes de cruzamento de dados que possibilitam verificar os relacionamentos existentes entre os campos. Quanto à produtividade dos docentes autores, que estão distribuídos em 5 universidades (USP, UNESP, UFMG, UnB e UFF), a análise dos dados revelou que o conjunto manteve uma média de publicação de 4 a 5 artigos por ano, durante o período de 1990 a 2006. Esses artigos foram publicados em quatro idiomas – português, inglês, espanhol e francês - em 27 periódicos de 9 países, sendo 18 deles publicados no Brasil verificando-se, ainda, uma forte tendência a publicar em periódicos conceituados e de qualidade comprovada. Uma análise das 817 referências contidas nos artigos revelou um total de 659 autores citados e uma preferência pela utilização de livros como fonte de informação na ordem de 50%, assim como a predominância de autores clássicos da área como base teórica. Além disso, foi identificada uma presença em torno de 20% da produção do grupo de docentes na literatura utilizada na área, caracterizando o impacto e o valor da produção desses docentes para a área. / Aiming at characterizing the scientific production of professors in the area of Subject Treatment of Information – S.T.I., 77 Journal articles by 19 post-graduation professors acting in the field, were selected, so as to detect the characteristics of this production and information sources utilized by authors- professors which may provide a wider knowledge of the area as an academic acting space. From the information provided by these articles, a database encompassing fields such as author, title of the article, title of publication, keywords, citations, country, language, year of publication and institution of the author, was compiled. The VantagePoint software, which organizes the information allowing the generation of lists and data-crossing matrices, which in turn enable one to verify the existing relationships among the fields, was used. As for the productivity of authors-professors who are distributed in 5 universities (USP, UNESP, UFMG, UnB and UFF), a data analysis showed that group kept an average of 4 to 5 articles per year, from 1990 to 2006. These articles were published in four languages – Portuguese, English, Spanish and France – in 27 Journals of 9 countries, being 18 published in Brazil and a strong trend to publish in renowned and high quality Journals was seen. An analysis of the 817 references contained in the articles, revealed a total of 659 authors cited and a 50% preference for books, as an information source, as well as the predominance of classical authors of the area, used as a theoretical base. In addition, some 20% of the professors’ production in the literature used in the area, was identified, thus characterizing the impact and importance of this production for the field. The subjects approached were identified from the key-words utilized, demonstrating a predominance of interest for the processes of the area, being indexing the most frequent subject.

The ability to carry communication services around, combined with the ubiquitous presence of computing technology, affects everything we do from how we pay for things to how we expect to interact with public institutions such as schools. There are now plenty of systems that convey education by utilizing mobile devices. As an extension of technology moving towards ubiquity, there are efforts aiming to bring this to an educational use as well. Efforts in this direction are channelized in the field of mobile learning. The speed of technological development, and the possibilities it brings introduces a large number of challenges when implemented in educational settings. These challenges can be related to for example pedagogical aspects, tools, implementations and organizations. Recent developments including the notions of learning ecosystems, learning landscapes and organizations suggest that the domain of mobile learning can be negatively affected from the lack of a systematic reuse approach. This thesis pursues these challenges by investigating how systematic reuse can be promoted in mobile learning systems. A collection of five peer-reviewed publications that elaborates on the different stages of the research process pursuing the main research question forms the core of this thesis. This research process includes a survey stage, elaborating on different aspects related to reuse and mobile learning, an analysis stage that resulted in a descriptive model and several additional domain models; and finally a stage where the descriptive model is refined into a reference model for mobile learning ecosystems. The outcomes of these activities and the analysis of these results provide some fundamental building blocks regarding how to approach the challenge of reuse in mobile learning systems. The proposed reference model can be considered as the first step towards the creation of a common vocabulary that can be used to compare Software Ecosystems within the domain of mobile learning.

Interaction of various components in rotating machinery like gearboxes may generate excitation forces at various frequencies. These frequencies may sometimes overlap with the frequencies of the forces generated by other components in the system. Conventional vibration spectrum analysis does not attenuate noise and spectral frequency band overlapping, which in many applications masks the changes in the structural response caused by the deterioration of certain components in the machine. This problem is overcome by the use of time domain averaging (dsynchronous averaging). In time domain averaging, the vibration signal is sampled at a frequency that is synchronized with the rotation of the gear of interest and the samples obtained for each singular position of the gear are ensemble-averaged. When sufficient averages are taken, all the vibration from the gearbox, which is asynchronous with the vibration of the gear, is attenuated. The resulting time synchronously averaged signal obtained through this process indicates the vibration produced during one rotation of the monitored gear. This direct time domain averaging process essentially acts as a broadband noise synchronous filter, which filters out the frequency content that is asynchronous with the vibration of the gear of interest provided that enough averages are taken. The time domain averaging procedure requires an enormous amount of vibration data to execute, making it very difficult to develop online gearbox condition monitoring systems that make use of time domain averaging to enhance their diagnostic capabilities since data acquisition and analysis cannot be done simultaneously. The objective of this research was to develop a more efficient way for calculating the time domain average of a gear vibration signal. A study of Artificial Neural Networks (ANNs) and Support Vector Machines (SVMs) was conducted to assess their suitability for use in time domain averaging. Two time domain averaging models that use ANNs and SVMs were developed. Model 1 uses a single feedforward network configuration to map the input which are rotation synchronized gear vibration signals to the output which is the time domain average of the gear vibration signal, using only a section of the input space. Model 2 operates in two stages. In the first stage, it uses a feedforward network to predict the instantaneous time domain average of the gear vibration after 10 inputs (10 rotation synchronized gear vibration signals) to predict the instantaneous average of the gear rotation. The outputs from the first state are used as inputs to the second stage, where a second feedforward network is used to predict the time domain average of the entire vibration signal. When ANNs and SVMs were implemented, the results indicated that the amount of gear vibration date that is required to calculate the time domain average using Model 1 can be reduced by 75 percent and the amount of gear vibration data that needs to be stored in the data acquisition system when Model 2 is used can be reduced by 83 percent. / Dissertation (M Eng (Mechanical and Aeronautical Engineering))--University of Pretoria, 2006. / Mechanical and Aeronautical Engineering / unrestricted

This diploma thesis deals with the algorithms for signal processing in a field of a low-coherence interferometry. The introductory part is devoted to the basic principle of the low-coherence interferometry and to presenting its field of applications. The second part contains a list of selected algorithms supplemented by a description of their functionality. The procedure of experimental measurement of known surface with Michelson interferometer is described in the third part and the results obtained for particular algorithms are presented. Finally, algorithms are compared on the basis of measurement results.

Des systèmes avec des coefficients dépendant du retard ont été rencontrés dans diverses applications de la science et de l'ingénierie. Malgré la littérature abondante sur les systèmes de temporisation, il y a peu de résultats concernant l'analyse de stabilité des systèmes avec des coefficients dépendant du retard. Cette thèse est consacrée à l'analyse de stabilité de cette classe de systèmes.Les méthodes d'analyse de la stabilité sont développées à partir de l'équation caractéristique correspondante suivant une approche généralisée tau-décomposition. Étant donné un intervalle d'intérêt de retard, nous sommes capables d'identifier toutes les valeurs de retard critique contenues dans cet intervalle pour lesquelles l'équation caractéristique admet des racines sur l'axe imaginaire du plan complexe. Le critère de direction de croisement des racines sont proposées pour déterminer si ces racines caractéristique se déplacent vers le plan complexe demi-gauche ou demi-droite lorsque le paramètre de retard passe par ces valeurs de retard critique. Le nombre de racines caractéristiques instables pour un retard donné peut ainsi être déterminé. Notre analyse comprend les systèmes avec un seul retard ou des retards proportionnés sous certaines hypothèses. Le critère de direction de croisement des racines développés dans cette thèse peut être appliqués aux multiple racines caractéristiques, ou aux racines caractéristiques dont la position paramétrée par le retard est tangent à l'axe imaginaire. En tant qu'application, il est démontré que les systèmes avec des coefficients dépendant du retard peuvent provenir de schémas de contrôle qui utilisent une sortie retardée pour approcher ses dérivés pour la stabilisation. Les méthodes d'analyse de stabilité développées dans cette thèse sont adaptées et appliquées pour trouver les intervalles de retard qui atteignent un taux de convergence demandé du système en boucle fermée. / Systems with delay-dependent coefficients have been encountered in various applications of science and engineering. However, general and systematic stability analysis is rarely reported in the rich literature on time-delay systems. This thesis is committed to the stability analysis of such class of systems.Stability analysis methods are developed based on the corresponding characteristic equation following a generalized tau-decomposition approach. Given a delay interval of interest, we are able to identify all the critical delay values contained in this interval for which the characteristic equation admits roots on the imaginary axis of the complex plane. Various root crossing direction criteria are proposed to determine whether these characteristic roots move toward the left or the right half complex plane as the delay parameter sweeps through these critical delay values. The number of unstable characteristic roots for any given delay can thus be determined. Our analysis covers systems with a single delay or commensurate delays under certain assumptions. The root crossing direction criteria developed in this thesis can be applied to characteristic roots with multiplicity, or characteristic roots whose locus parametrized by the delay is tangent to the imaginary axis. As an application, it is demonstrated that systems with delay-dependent coefficients can arise from control schemes that use delayed output to approximate its derivatives for stabilization. The stability analysis methods developed in this thesis are tailored and applied to find the delay intervals that achieve a demanded convergence rate of the closed-loop system.

Yes / To support various fifth generation (5G) wireless applications, a small, printed bowtie-shaped microstrip antenna with meandered arms is reported in this article. Because it spans the broad legal range, the developed antenna can serve or reject a variety of applications such as wireless fidelity (Wi-Fi), sub-6 GHz, and ultra-wideband (UWB) 5G communications due to its multiband characterization and optimized rejection bands. The antenna is built on an FR-4 substrate and powered via a 50-Ω microstrip feed line linked to the right bowtie’s side. The bowtie’s left side is coupled via a shorting pin to a partial ground at the antenna’s back side. A gradually increasing meandering microstrip line is connected to both sides of the bowtie to enhance the rejection and operating bands. The designed antenna has seven operating frequency bands of (2.43–3.03) GHz, (3.71–4.23) GHz, (4.76–5.38) GHz, (5.83–6.54) GHz, (6.85–7.44) GHz, (7.56–8.01) GHz, and (9.27–13.88) GHz. The simulated scattering parameter S11 reveals six rejection bands with percentage bandwidths of 33.87%, 15.73%, 11.71, 7.63%, 6.99%, and 12.22%, respectively. The maximum gain of the proposed antenna is 4.46 dB. The suggested antenna has been built, and the simulation and measurement results are very similar. The reported antenna is expanded to a four-element design to investigate its MIMO characteristics. / Partially funded by British Council “2019 UK-China-BRI Countries Partnership Initiative” program, with project titled “Adapting to Industry 4.0 oriented International Education and Research Collaboration.

The motivation for computer forensics research includes the increase in crimes that involve the use of computers, the increasing capacity of digital storage media, a shortage of trained computer forensics technicians, and a lack of computer forensics standard practices. The hypothesis of this dissertation is that domain modeling of the computer forensics case environment can serve as a methodology for selecting keyword search terms and planning forensics examinations. This methodology can increase the quality of forensics examinations without significantly increasing the combined effort of planning and executing keyword searches. The contributions of this dissertation include: ? A computer forensics examination planning method that utilizes the analytical strengths and knowledge sharing abilities of domain modeling in artificial intelligence and software engineering, ? A computer forensics examination planning method that provides investigators and analysts with a tool for deriving keyword search terms from a case domain model, and ? The design and execution of experiments that illustrate the utility of the case domain modeling method. Three experiment trials were conducted to evaluate the effectiveness of case domain modeling, and each experiment trial used a distinct computer forensics case scenario: an identity theft case, a burglary and money laundering case, and a threatening email case. Analysis of the experiments supports the hypothesis that case domain modeling results in more evidence found during an examination with more effective keyword searching. Additionally, experimental data indicates that case domain modeling is most useful when the evidence disk has a relatively high occurrence of text-based documents and when vivid case background details are available. A pilot study and a case study were also performed to evaluate the utility of case domain modeling for typical law enforcement investigators. In these studies the subjects used case domain models in a computer forensics service solicitation activity. The results of these studies indicate that typical law enforcement officers have a moderate comprehension of the case domain modeling method and that they recognize a moderate amount of utility in the method. Case study subjects also indicated that the method would be more useful if supported by a semi-automated tool.

The Finite-Difference Time-Domain (FDTD) method has gained tremendous popularity in the past decade as a tool for solving Maxwell's equations. Phased Array Antennas find several applications including mobile communications ( cellular, personal communication systems and networks), satellite communications, global positioning system (GPS), aeronautical and radar systems. This dissertation describes the application of the FDTD method for calculating broadband characteristics of finite-sized phased array antennas consisting of microstrip elements fed with coaxial probes. The characterization of such antennas is dependent upon the development of simulation tools that can accurately model general topologies including wires, dielectrics, conductors lumped elements and metallic strips. The use of these simulation tools reduces the cost and effort associated with fabricating and testing phased array antennas. The FDTD formulation is inherently broadband, very general, and easily accorrunodates arbitrary conductor geometry and dielectric configurations. The FDTD method is implemented and applied to determine the input impedance, radiation-patterns and gain of microstrip antennas. Next, the main contributions of this work are described which include the full time-domain characterization of broadband characteristics of finite-sized phased array antennas for different scan conditions. Active reflection coeffici nt gain scan-element patterns and scanning-array radiation patterns are calculated.

<p>This thesis proposes a new analytical self-adjoint sensitivity analysis to calculate the Jacobian of the <em>S</em>-parameters for metallic shape parameters. This method is independent of the full-wave numerical analysis and the respective system matrix. The theory works for both volumetric and infinitesimally thin metallic shapes. It exploits the computational efficiency of the self-adjoint sensitivity analysis (SASA) approach where only one EM simulation suffices to obtain both the responses and their gradients in the designable parameter space.</p> <p>There are three major advantages to this development: (1) the Jacobian computation for metallic structures is completely analytical and there is no approximation involved in the sensitivity analysis of shape parameters; (2) the implementation is straightforward and in the form of a post-processing algorithm operating on the exported field solutions on the surface or around the edge of the metallic structure; and (3) it provides the possibility for exact sensitivity analysis with all electromagnetic high-frequency simulators whose system matrices are not available to export or are not differentiable with respect to shape parameters, e.g., simulators based on the FDTD method and the MoM.</p> <p>The method was verified in a number of examples using a commercial finite-element solver. The agreement between the results calculated with the proposed method and the reference self-adjoint sensitivity curves provided with the simulator are very promising.</p> <p>Suggestions for future work are provided.</p> / Master of Applied Science (MASc)