RCAAP Repository

Biometrics provides a reliable authentication mechanism using physical or behavioral traits to identify users based on their natural characteristics. Fingerprint recognition is one of the most used biometrics approach, since its high accuracy and low cost make the system more affordable and acquire satisfactory results. However, fingerprint recognition is still an open problem, since false acceptance and false rejection errors are still found in matching algorithms. This research aims to create new methods in order to facilitate the feature extraction process, improving image quality through the use of inovative segmentation and enhancement techniques, seeking to reduce error rates and achieve competitive results among state-of-the-art algorithms. The main contributions of this work were the creation of the following methods: segmentation of the region of interest of fingerprint images, reaching error rates lower than the best segmentation algorithms in the world in 10 of 12 databases evaluated, obtaining an average gain of 5.6% over the best current segmentation algorithm; creation of the complete feature extraction method, based on state of art works, making corrections and innovations at key points to obtain better results. The feature extraction method was evaluated through the submission of the algorithm to the Fingerprint Verification Competition (FVC), obtaining promising results, being classified as the second best algorithm between research groups and the only algorithm of Brazilian origin. In addition, when the comparison with the base enhancement algorithm of this work was done, the method developed in this research obtained gains of 21% in accuracy.

Nowadays, technology is present in almost every work process and consequently the demand for technological resources is more and more frequent, leading to further changes in software systems, mainly due to additional maintenance requests, and, therefore, a greater number of bugs for correction. Taking into account that bug fixing is one of the factors that impacts on software quality improvement, but at the same time represents a high expenditure of resources in a software project, bug fixing processes represent a critical hurdle for software maintenance and development. Given that the number of existing reported bugs may be greater than the resources needed to correct them, and the fact that many software companies currently work with successive deliveries, called releases, which allow the delivery of parts of the software product, project managers may face the challenge of manually selecting the bugs to be fixed in the next software version, usually based on the criteria of priority and severity, indicated in the respective bug reports, as well as delivery time or cost. For this, project managers adopt the socalled Bug Tracking Systems (BTS), which establish communication channels between software producers and their customers. For large and complex systems, where a substantial number of bug reports are common, a bug selection approach based on the ad-hoc judgment of experts is not efficient and effective, representing a time-consuming, labor-intensive and errorprone strategy. In such a context, exploring Search Based Software Engineering (SBSE) techniques, this dissertation proposes an automated approach for selecting interdependent bugs in component-based software projects, adopting a multiclient model to select the most relevant bugs from the point of view of both the software producer and its customers, but with total cost limited by the budget available in the software project. In order to evaluate the proposed approach, two case studies were carried out, where the search strategy based on genetic algorithm is compared with other strategies based on both exhaustive and random algorithms, and, more realistically, also compared with the selection based on knowledge and experience of systems analysts. The expressive results obtained in the case studies express the feasibility, practicality and effectiveness of the proposed approach.

In this project, we developed an embedded system for a flight cotroller applied to quadrotor UAVs. Built with accessible components, open hardware architecture and open software, it makes possible the tests and implementation of new control algorithms by the user, setting it apart from the most common alternatives available on the market. Therefore, there is a sensoring system for capturing and recording the quadrotor odometry, the angular velocity com mandsaresentto the motors via PWM,and the processing is madeona Raspberry Pi3. For architecture validation, experiments were performed on each component, individually and together with the whole system, analysing then the aplicability to the desired goal. Furthermore, a study of the mathematical modeling and structure of a quadcopter was conducted. Lastly, the tuning of a Proportional Integral Derivative controller was tested to verify the operation of the developed device.

The Higher Education comes as an essential part to bring professional qualification and improve the quality of individuals' lives. Despite all the advantages that professional qualification has to offer, there may be mishaps during the academic life that are often not overcome by the student / individual and result in the loosing of the aimed graduation. Moreover, in a range of four / five years, the relative rate of students graduating (input / output) is around 55 percent, and 30 percent in the distance learning. (MAIA, 2008). Several studies indicate possible causes of dropout, such as approval in another institution / course of major interest, retention in disciplines in the first four semesters of the course, lack of support and accompaniment of the student, academic deficiencies arising from Basic Education conflicting with the requirements of Higher Education. Especially about the lack of support and monitoring of the student, this work is based on the premise that collaborative learning activities, mainly when carried out in small groups and supported by elements that promote collaboration, present positive effects by increasing the ability of knowledge acquisition of students, reducing costs and promoting alternatives to solve the retention problem on disciplines. After the search and analysis of several theories/methods on collaborative learning, three approaches were chosen to be evaluated. Through some validation tests with users, it was measured that the applied strategies are in fact effective. The results pointed that the strategies may be applied to a computational resource to encourage collaboration among participants.

The work present under the defined theme "The criminal organizations in the world economic order", it objectifies to analyze the expansion of the criminal transnational in the context of the globalization, phenomenon that despairs jurists and government authorities, constituting permanent trouble to States and international organisms. In the text the author discusses the world ascent of the organized crime with base in the regent paradigms of the world capitalist system, emphasizing the exacerbated liberalism and the technician-scientific progress as decisive factors. The author also highlights the splendid development of the criminal entities that expand in international connections and prosperous operations of "money laundering", indispensable instruments to the fertilization of the crime on world territory.

In this work, we propose fuzzy clustering methods based on a Mahalanobis-type kernel with adaptive quadratic distances de ned either by fuzzy covariance matrices that are commom to all clusters or by a fuzzy covariance matrix that can be different for each cluster. These matrices can be also full or diagonal. The Mahalanobis-type kernel functions were built from adaptive quadratic distances parameterized by symetric, positive-defined matrices that changes at each iteration of the algorithm. The proposed algorithms were evaluated and compared with the main clustering methods in the literature as well as with their kernelized versions through experiments with simulated and real data.

The aim of this investigation relies in the possibility of establishing the enlargement of the material competence in the international criminal court. It also analyses the new world scenery, highlighting the technological revolution in the means of communication as well as the global expansion of capital ideology and its reflection on this ideology in the sovereignty of the national states. It examines the international criminal courts of Nuremberg, Tokyo, ex-Yugoslavia and Ruanda, in which the objective was to explain the influence of those in the creation of the International Criminal Court. It highlights the world projection of the economical organized criminality in the light of the modern economy order, as wel as the possibility and efficiency of the enlargement of the ICC competence to embrace the specific criminal modality.

In lastest years, have been noticed the growth of social interest house in Brazil. However, the lower housing conditions and environmental degradation are characteristics of most of the produced housing. Financial constraints have been the main argument to justify these deficiencies. Seeking technical solutions, concerned with regard to environmental and economic issues for the construction sector, the use of gypsum is advantageous because it is less aggressive caking for the environment. Thus, this study aims to verify the changes in the physical and mechanical properties, and thermal performance of composite gypsum matrix with polymeric waste additions such as Ethylene Vinyl Acetate (EVA) and Expanded Polystyrene (EPS). The composite of gypsum and waste of EVA and EPS were used in the production of blocks for masonry sealing. It was also used bottles of PET (Poly Ethylene Terephthalate) inside of the produced blocks called in this work, GESSOPET. It has been found that the gypsum composite blocks of residues, both EVA as EPS showed better related to the thermal performance when compared with block without waste additions, manufactured only with plaster. Finally, this paper aims to contribute to the development of construction technologies using raw materials with low environmental impact and promote more economic construction.

The semidefinite programming techniques, which allow to work with optimization problems subject to matrix constraints, are very efficient in structural optimization applications. Using these techniques, the present dissertation presents a new numerical algorithm, the FDIPA-GSDP(3), belonging to the family FDIPA-SDP-NL, capable to solve large optimization problems. Its differential is in the formulation of a new Newton system, whose function is to find a direction that is at the same time descent and viable, with dimensions quite reduced compared to previous versions, which facilitates their storage in memory and makes possible its application in problems that require a great number of elements in the discretization of the structure. In order to show the performance of this algorithm, numerical results of the applications developed in a classical problem of structural optimization are presented: maximization of the natural frequency of structures subject to volume and compliance constraints.

In this work, we present extensions for known subtractive clustering methods. The subtractive clustering method for symbolic interval data (iSBC) as an extension of the subtractive clustering method developed by Chiu (1994), as well as the kernelbased subtractive clustering methods defined by one or two components for symbolic interval data (iKSBC1C and iKSBC2C, respectively) as extensions of a kernel-based subtractiveclusteringmethodproposedbyKimetal. (2005). Inaddition, sixstrategies will be proposed: the centroids of the proposed methods will be given as inputs to the methods K-means for interval data based on L2 distance proposed by De Carvalho, Brito and Bock (2006) (iKM+iSBC, iKM+iKSBC1C and iKM+iKSBC2C) and kernel K-means for symbolic data of the interval-valued developed by Costa (2011) (iKKM+iSBC, iKKM+iKSBC1C and iKKM+iKSBC2C) as a way to minimize the sensitivity of these methods to the choice of the centroid for de nition of the initial partition. Experiments using real data showed that the proposed kernelbased subtractive clustering methods (iSBC1C and iSBC2C) obtained better performance than the iSBC method, as well as the K-means (iKM+iSBC, iKM+iKSBC1C and iKM+iKSBC2C) and kernel K-means (iKKM+iSBC, iKKM+iKSBC1C and iKKM+iKSBC2C) methods, both for symbolic data interval-valued, using the centroids of methods proposed as inputs for them also obtained better performance that the iKM and iKKM methods.

This work study the problem of maximizing the fundamental frequency of trusses and the effect of including a non structural mass. The problem of maximizing the natural frequencies of structures is important for mechanical engineering applications, however, the optimization model has difficult technical issues when some structural element is removed (topology optimization). Fortunately, there exists theoretical results that transforms the original problem in a semidefinite optimization model. In this sense, the present work shows the mathematics to define the semidefinite model for the maximum eigenfrequency problem. To solve that problem numerically, the Feasible Arc Interior Point Algorithm (FAIPA-SDP) is employed. Some numerical examples are solve with this algorithm. Those numerical examples shows that FAIPA-SDP solve the optimization problems. Those results also confirm all the theoretical properties presented in this work.

Statistical Mechanics appeared in the middle of 1850, is based on the attempt of the use of microscopic models, with the intention of describing macroscopic phenomena. In general, such models have stochastic dynamics. That is, the micro-system particles evolve stochastically. In this work we are interested in certain systems which are called Markov Chains at continuous time, where the particles are located at points of the cartesian plane Z2. In our work, the dynamics used is that of Kawasaki, the original con guration of the particles is distributed in the format a cross. In models of statistical mechanics there is a function that is called by many by function energy (H). At each movement of the particles we have a new energy value for this new con guration. The system addressed in this work is such that it always seeks the lowest state of energy. In this search the system may be stuck in a certain valley for a long time (such phenomenon characterizes a metastate). However, for a very long time interval the system converges to a real state of equilibrium called the macro state. In our work we aim to verify the metastability of the particle system, starting from the simplest case, where the system is composed of only twelve particles and later we will study the system metastability of a larger number of particles. As a result of the work we will get the probability of the particle system reaching a certain macro state.

In this dissertation we present the study and application of a tool derived from the Theory of Games called the iterated elimination of strictly dominated strategies or actions (IESD). Using the Python programming language, this work focuses on the construction and application of an algorithm based on this tool to solve a hypothetical situation of conflict between two spaceships. The analysis takes place from the perspective of one of the players and various models of distributions to qualify how a winner is chosen are adopted and simulated. To win one of the players must make a series of path choices to be a winner, and a wrong choice means their destruction. In general the use of IESD was more advantageous than the random choice.

Mediation is an Alternative Dispute Resolution (ADR) that is becoming increazingly important Brazil, in which a neutral third party facilitates the parties' own settlement process. The present research reflects about this mechanism's political potential, based on a community mediation experience (internship at Juspopuli human right organization — Salvador-BA). There are four fundamental points in our research. The first one is about mediation itself: what people commonly think about it and where are the critical reflections about its usage directed to. The second one is the conflict: how we experience it in our culture, which elements need to be reflected upon so that the role of conflict can be changed in our society and community mediation as a builder of a dialogue culture. The third one is the right: the defining elements of the traditional comprehension of the juridical phenomenon, with its reduction to the law, an other possible paradigms in the field of critical theories of law which are meant to support community mediation practices. Finally, the parties: the prevailing idea we have about them and a critical panorama to encourage autonomy and respect for the other in the construction of new forms of subjectivity through community mediation.

Thestability of trajectories in the phase space of a dynamical system can be characterized through Lyapunov characteristic exponents. In simple situations, these exponents correspond to the eigenvalues of the linearized equation of motion. However, for complex trajectories occurring in many nonlinear systems, specially during the occurrence of chaos, the determination and the very concept of stability and of the values of those exponents becomes more elusive, creating technical difficulties. This work makes a pedagogical review, presenting and explaining the concepts of stability, and Lyapunov exponents, discusses its application to the characterization of nonlinear dynamical systems, and proposes a study about the techniques do evaluate those exponents. To illustrate this study, we analyze some specific systems, such as Lorenz’s and Rössler, and discuss the properties that can be inferred from our study.

In the beginning of the XXIst century, Brazilian educational policy has been consolidated in the mercantilist scenario influenced by the global economy and this was not a characteristic phenomenon only in the private ambit. Approaching the theory of quasi-market it was evidenced a model of educational management focused in performance, developed in the public sphere. In this study, neoliberal ideas emerge with the creation of PDRAE, in FHC government, that potentializing the Minimum State contributes with the dissemination of non-governamental organizations to accomplish the competeces of State. In this context appears IAS – Ayrton Senna Institute, whose philosophy based on human development and praxis supported by the use of social technologies directed to education, making a partnership with public systems of teaching. Aiming an evaluative analysis of the performance of Cabedelo/PB SME – Municipal Teaching System, where since 2001 IAS works with its educational policy in the first phase of fundamental education through Programs that constitute the Win Web. This research presents results obtained in the mentioned town based on the IDEB – Basic Education Development Index and the Failure Rate (TR) according to INEP – Anísio Teixeira National Institute of Educational Researches and SIASI – Ayrton Senna Institute System of Information. Since the usage of instruments and technologies of social-educational intervention of IAS, as well as in the measurement of INEP indexes, it is explicit the relevance of considering the failure rate in the beginning grades as a variable of great importance to draw strategies of control and followup of the pedagogic processes, aiming the enhancing of the references of quality of teaching and consequent rise of IDH-E in the town, in the Management State logic. Conclusion points out that there was a significative improvement of the performance of Cabedelo/PB SME when analyzing from IDEB, but according to references of demographic indicators and Edudata Brasil the numbers are different in their database, thus, qualitatively compromising the obtained results.

In the last decades, mainly due to the advent of new technologies, with the exponential growth of the population, the intensification of the use of fossil fuels has generated great impacts to the environment. In this scenario, the search for energy alternatives has been constant. A rising solution is the use of the fuel cell technology, which has the principle of converting chemical energy into electrical energy. This work aimed to study calcium cobaltite as a potential cathode material for solid oxide fuel cells (SOFC). Powders of composition Ca3CuxCo4-xO9-d (0 = x = 0.15) were obtained using the Pechini method modified by using gelatin. The obtained powders were calcined at 900 °C for 2 h and characterized by X-ray diffractometry (XRD) and scanning electron microscopy (SEM). The lattice parameters were determined by Rietveld refinement of the diffraction data. The electrochemical characterization was performed under open circuit conditions and under cathodic polarization using a 3 electrode configuration. The results of XRD and SEM indicated the attainment of particles of Ca3CuxCo4-xO9-d solid solutions free of secondary phases and in the format of microplates up to 5 m in diameter. The electrochemical results highlight the potential of calcium cobaltite as a cathode material of SOFC, presenting total polarization resistance (Rp of 2.8 ? cm2 at 700 ° C in oxygen) competitive with cobaltites from literature and low values of cathodic polarization (123 mV at 700 ° C and 100 mA/cm2) in comparsion to alternative cathodes for SOFC.

Discovered by Dan Shectman in 1982. Quasicrystals, ordered and aperiodic structures, are intermetallic compounds that have very different thermal and surface properties than conventional crystal structures. They are hard and brittle at room temperature, however because they have low thermal conductivity and low coefficient of friction, research suggests the application of these materials as hard coatings (high resistance to wear) and thermal barrier. The HVOF thermal spray process excels in obtaining thick and dense coatings. However, due to the large number of operational variables, a process optimization is still sought to improve the quality of the deposited quasicrystalline coatings. This work aimed to investigate the effects of O2 / fuel ratio on the microstructural integrity and properties of QC coatings. Quasicrystalline coatings on steel substrate were produced by HVOF (high velocity oxyfuel). The raw material was used twice in the production of powder: Al59,2Cu25,5Fe12,3B3 (icosahedral symmetry) with particle size ranging from 25-54 µm. Al65Co18Cu17 (decagonal symmetry) irregular geometry (polygonal and faceted) with piece size between 25-75 µm. The coatings were produced with five spray conditions from the variation in O2/kerosene ratio: 0.98 (fuel), 1.04 (fuel), 1.10 (stoichiometric), 1.16 (oxidant) and 1.22 (oxidant). The effect of the O2/kerosene ratio on the microstructure and coating properties was analyzed by X-ray diffraction, electron microscopy and x-ray photoelectron spectroscopy (XPS). The properties of hardness and modulus of elasticity were evaluated along the cross section of the coatings for each spray condition. In addition, the structural integrity of the coatings was monitored by the three-point flexural test coupled to piezoelectric sensors with the traction coating. The use of this technique, unprecedented in QC coatings, proved to be able to qualitatively determine the degradation of coatings under load. The coating Al59,2Cu25,5Fe12,3B3 produced with fuel ratio A5 (0.98), showed low porosity (<1.5%). This low porosity reflected in the hardness and modulus of elasticity, about 696.5 HV and 160.0 GPa respectively. Moreover, it was verified that the increase in the O2/fuel ratio was harmful, since it promoted a greater accumulation of defects in the microstructure of the coatings, impossible to be detected in the previous analyzes. This result was evident with the monitoring of the structural integrity (energy analysis of the D4 detail of the wavelet). The increase in the O2/kerosene ratio promoted a large increase in defects and discontinuities, which the energy for the coatings of AlCuFeB, A1 (1.22) oxidant ratio, is ten times smaller when compared to the A5 (0.98) fuel ratio. The porosity was 8.0% for the Al65Co18Cu17 coating, best result obtained with condition B3 (1.10), high value for coatings obtained by HVOF. The hardness and modulus of elasticity presented values of approximately 700 HV and 170 GPa respectively. Finally, the coatings produced with Al65Co18Cu17, regardless of the spray condition, presented high defects and discontinuities, a result of the low energy, verified through the monitoring technique with piezoelectric sensors.

In the search for renewable and environmentally friendly energy sources, hydrogen production and solid oxide fuel cell (SOFC) research have been prominent. Nickel and gadolinia doped ceria (Ce1-xGdxO2-? - CGO) based anodes have presented good electrochemical performance at intermediate temperatures (600-800 °C), allowing the direct oxidation of gases with hydrocarbons. Precursors of nickel, copper and cobalt bimetallic cermets (ceramic-metal composites) were obtained by the one-step synthesis method to evaluate their electrochemical performances as SOFCs anodes and to evaluate their catalytic behavior in dry methane reforming. NiO-Ce0.9Gd0.1O1.95 (NiO-CGO), NiCuO-CGO and NiCoO-CGO composite powders had their catalytic activities in reforming the methane, for hydrogen production, evaluated in the temperature range 400-800 ºC. These materials were also studied as solid oxide fuel cell anodes. Symmetrical anode/electrolyte/anode cells were prepared by screen-printing. The electrochemical activity was performed under typical anode operating conditions (reducing atmosphere in the temperature range between 650 and 750°C), using hydrogen and biogas as fuels. X-ray diffraction (XRD) analysis of powders calcined at 700 °C confirmed the attainment of NiO (NaCl-type), Co3O4 (spinel-type), CuO (tenoritetype) and Ce0.9Gd0.1O1.95 (fluorite-type). The crystallite size analysis indicated the obtaining of nanometric powders. The cobalt-based samples presented specific area values (evaluated by the BET method) higher than those of copper-based samples. Temperature programmed reduction (TPR) analysis indicated that the reducibility of the Ni-containing phase and its interaction with the CGO support are influenced by the presence and amount of cobalt and copper. The sample Ni0.2Co0.8O-CGO (NiCo0.8) showed high reduction capacity and strong metal/support interaction. The Rietveld refinement analysis for the reduced catalysts confirmed the presence of the Ni-Co alloy. These factors played a key role in enhancing catalytic activity and suppressing carbon deposition. The characterization of the catalysts after reaction by thermogravimetry and differential scanning calorimetry (TG-DSC) showed a better resistance to carbon deposition for NiCo catalysts. These catalysts showed higher conversions of CH4 and CO2 than NiCu and NiCGO catalysts. The NiCo0.8 catalyst showed a slightly higher CH4 conversion, better reaction selectivity between 600 and 750°C and better resistance to carbon deposition than Ni0.6Co0.4O-CGO (NiCo0.4). The methane reforming reaction with CO2 seems to be more favorable in the presence of the NiCo0.8 catalyst. The electrochemical characterization using impedance spectroscopy showed that the same electrode presents different electrochemical behaviors in hydrogen and biogas. In terms of overall behavior, NiCu0.8 is better than CuCGO in hydrogen. The inverse occurs in biogas, where the CuCGO anode performance is twice that of NiCu0.8. The calculation of the activation energies indicates that the complexity of the dry reforming of methane limits the electrochemical activity of the anodes in biogas.

Natural antimicrobials are effective and economical alternatives as they are obtained from aromatic plants and rich spices as essential oils characterized by a remarkable antimicrobial activity, and for this reason their products can be used to retard or inhibit the microbial multiplication so found in skin infections. In order to provide quick-relief treatments for wound infection, natural bioactives such as clove and melaleuca oils as well as cashew and noni sprayed juices and powders have been proposed in this work as a research object to obtain an antimicrobial dressing based on chitosan, aiming to optimize the rehabilitation of these lesions. Chitosan membranes containing natural bioactives were prepared by the method of solvent evaporation (casting) and evaluated qualitatively by visual aspect and characterized by thickness, contact angle wettability, swelling degree, Fourier transform infrared spectroscopy (FTIR) , scanning electron microscopy (SEM) and traction test, while chitosan / bioactive emulsions were submitted to antimicrobial activity by the agar diffusion method. Visible light transparency (colorless) presented by pure chitosan membrane underwent changes with the type and concentration of the incorporated bioactive. The chitosan membranes presented contact angle ranging from 40° to 90° in distilled water and PBS, which classified them as hydrophilic materials. Natural bioactives have provided increased membrane hydrophilicity, which is an important result, since wettability is essential in curative materials. The natural bioactives provided improvements in the rate of absorption and stability of the CS1 membrane, especially the clove and melaleuca essential oils that showed significant swelling degrees in distilled water and PBS (rates ranging from 325.23% to 5176.63%). The tenuous properties of pure and incorporated chitosan membranes proved to be sufficient and compatible to be applied as curatives. Clove oil showed the highest inhibition against the microorganisms employed, with halos up to 36 mm (Staphylococcus aureus), followed by melaleuca oil (up to 12 mm Candida albicans) and noni pulp (up to 8 mm Staphylococcus aureus). The incorporation of the natural bioactives provided an increase in the antimicrobial activity of the CS1 emulsion against Staphylococcus aureus (CS1C3), Escherichia coli (CS1C3, CS1M1, CS1M3, CS1CJ3, CS1PCJ3, CS1PN1 and CS1PN1) and Candida albicans (CS1C1 and CS1M3) for such compositions in wound healing. And although the greater inhibition halo (10 mm) was found for the composition with 3% cashew juice compared to Escherichia coli, the essential oils had the highest action spectra. In order to do so, it was concluded that the essential oils of clove and melaleuca were the ones that demonstrated the best antimicrobial activities in the chitosan-based emulsions, presenting as potentially favorable oils in the process healing of skin lesions.