Navegando por Institutos "Instituto de Tecnologia"

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Acesso aberto (Open Access)
5G MIMO and LIDAR data for machine learning: mmWave beam-selection using deep learning
(Universidade Federal do Pará, 2019-08-29) DIAS, Marcus Vinicius de Oliveira; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
Modern communication systems can exploit the increasing number of sensor data currently used in advanced equipment and reduce the overhead associated with link configuration. Also, the increasing complexity of networks suggests that machine learning (ML), such as deep neural networks, can effectively improve 5G technologies. The lack of large datasets make harder to investigate the application of deep learning in wireless communication. This work presents a simulation methodology (RayMobTime) that combines a vehicle traffic simulation (SUMO) with a ray-tracing simulator (Remcom’s Wireless InSite), to generate channels that represents realistic 5G scenarios, as well as the creation of LIDAR sensor data (via Blensor). The created dataset is utilized to investigate beam-selection techniques on vehicle-to-infrastructure using millimeter waves on different architectures, such as distributed architecture (usage of the information of only a selected vehicle, and processing of data on the vehicle) and centralized architectures (usage of all present information provided by the sensors in a given moment, processing at the base station). The results indicate that deep convolutional neural networks can be utilized to select beams under a top-M classification framework. It also shows that a distributed LIDAR-based architecture provides robust performance irrespective of car penetration rate, outperforming other architectures, as well as can be used to detect line-of-sight (LOS) with reasonable accuracy.
Acesso aberto (Open Access)
A implantação de obras civis e de saneamento na Bacia do Una, em Belém do Pará, e as condicionantes relacionadas às características geológicas e geotécnicas
(Universidade Federal do Pará, 2004-04-26) SILVA, Kleber Roberto Matos da; ALENCAR JÚNIOR, Júlio Augusto de; http://lattes.cnpq.br/3663658632717465
This Thesis presents the civil engineering works for implementation of drainage and sanitation facilities in the area of influence of the Una canal, in the city of Belém, in the State of Pará, Brazil, involving the installation of drainage, water and sewer nets as well as road construction. This project, known as Project Una, involves an area of 3.644 ha, corresponding to approximately 21% of the continental area of city, with great part of its surface below flood level, that is, up to 3,60 m above sea level. The stratigrafy of the project area is composed basically of a thick superficial layer of very soft organic clay, that in some cases may reach over 60 m deep, overling intercalation of medium to compact sand layers and medium to hard silty clay layers. Besides the construction difficulties in soils of this nature, this work presents the many problems to resolved, as the resettlement of families of risk areas, that is, families that are living on the bed of channels, hindering the draining of the served waters and pluvial waters; the compensations of shaky residences for the works; the lack of physical space for the setting up of the works; the instability of the slopes of the marginal road of channels; the difficulties of management in the of face the extensive encircle of the area; the relationships with the community, tumultuated in some moments and, mainly, the priority of some areas, in detriment of other, for the execution of the works, in the face of available resources. Based in technical reports, projects and the author's personal experiences the thesis makes a description of the project in its several aspects, as well, makes a critical review of it, under the civil engineering’s point of view, involving planning and executions aspects of the works, with the purpose of building and setting up of the knowledge, that promote the improvement in future development in the similar projects.
Acesso aberto (Open Access)
Abordagem de leitura de texto em imagens provenientes de redes sociais para ganho em disponibilidade de dados
(Universidade Federal do Pará, 2017-10-19) FERREIRA NETO, Luiz Cortinhas; SANTANA, Ádamo Lima de; http://lattes.cnpq.br/4073088744952858
This work aims to propose a methodological adaptation in the process of social network analisys, based on the inclusion of text extracted from images that are obtained from the social networks themselves. Highly important for market intelligence, product analysis, CRM and SCRM processes, since these are market trends used by large companies, thus, promotes financial and research incentives. The adaptation proposed in here has its importance based on data availability, which has become increasingly restricted, thanks to the use of APIs, interfaces of data access management where, in several different ways, each social network limits the data query, either by type of data, quantity or collected window. This research intends to prove, through case studies, that there is relevant information gain to sentiment analyses process when textual data derived from images are used.
Acesso aberto (Open Access)
Uma abordagem heurística para os problemas de horários educacionais
(Universidade Federal do Pará, 2020-12-15) REIS, Williams Sousa dos; QUARESMA, João Nazareno Nonato; http://lattes.cnpq.br/7826389991864785
With each new school term, educational institutions have the hard work of allocating their class schedules, the problem implies in allocating time intervals and resources to activities, in such a way that they satisfy the restrictions imposed in the best possible way. This is a problem considered difficult to solve from the point of view of computational complexity theory. With this in mind, this work aims to develop a tool that can automate the time allocation process carried out by the Institute of Biodiversity and Forests (IBEF) at the Federal University of Western Pará (UFOPA), presenting a proposal based on the meta-heuristic known as genetic algorithm (AG). This proposal is submitted to several experiments with real data from that institution and the results are fully satisfactory, evidenced by overcoming the restrictions imposed by the problem in an acceptable computational time, bringing some advantages with the automation of the process, such as: reduction in time development of time allocation; and better reallocation and use of physical and human resources.
Acesso aberto (Open Access)
Uma abordagem híbrida e semiautomática para estimativa de regiões cobertas por nuvens e sombras em imagens de satélite: análise e avaliação
(Universidade Federal do Pará, 2014-03-31) SOUSA, Danilo Frazão; PELAES, Evaldo Gonçalves; http://lattes.cnpq.br/0255430734381362
The main goals of this work are to propose a more automatic and efficient algorithm to replace regions of clouds and shadows in satellite images as well as an index of reliability that is previously applied to each image, in order to measure the feasibility of the estimation of the regions covered by atmospheric components using that algorithm. The motivation comes from the problems caused by these atmospheric elements, among them: to impede the identification of objects of the image, to make the urban and environmental monitoring more difficult, and to interfere in crucial stages of digital image processing to extract information for the user, such as segmentation and classification. Through a hybrid approach is proposed a method for decomposing regions using a median non-linear low-pass filter, in order to map the regions of structure (homogeneous) and texture (heterogeneous) in the image. In these areas was applied restoration methods Inpainting by Smoothing based on Discrete Cosine Transform (DCT), and Exemplar-Based Texture Synthesis, respectively. It's important to note that the techniques have been modified to be able to work with images obtained through of satellite sensors with peculiar features such as large size and/or high spectral variation. Regarding to the reliability index, it aims to analyze the image that contains atmospheric interference and hence estimate how much reliable will be the redefinition, based on the percentage of cloud cover over the regions of texture and structure. This index is composed by combining the result of supervised and unsupervised algorithms involving three metrics: Average of Accuracy Global, Measure Of Structural Similarity (SSIM) and Average of Pixels Confidence. Finally, it was verified the effectiveness of these methods through a quantitative assessment (provided by the index) and qualitative (the images resulting from processing), showing the possible application of the techniques to solve the problems that motivated this work.
Acesso aberto (Open Access)
Abordagem Inteligente com Combinação de Características Estruturais para Detecção de Novas Famílias de Ransomware
(Universidade Federal do Pará, 2024-03-22) MOREIRA, Caio Carvalho; SALES JUNIOR, Claudomiro de Souza de; País de Nacionalidade Brasi
Ransomware is a malicious software that aims to encrypt user files and demand a ransom to unlock them. It is a cyber threat that can cause significant financial damage, as well as compromise privacy and data integrity. Although signature-based detection scanners commonly combat this threat, they fail to identify unknown ransomware families (variants). One method to detect new threats without the need to execute them is static analysis, which inspects the code and structure of the software, along with classification through intelligent approaches. The Detection of New Ransomware Families (DNFR) can be evaluated in a realistic and challenging scenario by categorizing and isolating families for training and testing. Hence, this thesis aims to develop an effective static analysis model for DNFR, which can be applied in Windows systems as an additional security layer to check executable files upon receipt or before execution. Early ransomware detection is essential to reduce the likelihood of a successful attack. The proposed approach comprehensively analyzes executable binaries, extracting and combining various structural features, and distinguishes them between ransomware or benign software employing a soft voting model comprising three machine learning techniques: Logistic Regression (LR), Random Forest (RF), and eXtreme Gradient Boosting (XGB). Results for DNFR demonstrated an average accuracy of 97.53%, precision of 96.36%, recall of 97.52%, and F-measure of 96.41%. Additionally, scanning and predicting individual samples took an average of 0.37 seconds. This performance indicates success in quickly identifying unknown ransomware variants and adapting the model to the constantly evolving landscape, suggesting its applicability in antivirus protection systems, even on resource-limited devices. Therefore, the method offers significant advantages and can assist developers of ransomware detection systems in creating more resilient, reliable, and fast-response solutions.
Acesso aberto (Open Access)
Uma abordagem matemática aplicada ao projeto de turbinas hidrocinéticas e eólicas com difusor utilizando a teoria do elemento de pá
(Universidade Federal do Pará, 2019-04-30) VAZ, Déborah Aline Tavares Dias do Rio; VAZ, Jerson Rogério Pinheiro; http://lattes.cnpq.br/1623983294183975
It is known surrounding a turbine with diffuser may significantly increase its power. This effect has attained considerable attention as it shows theoretically the possibility of achieving a power coefficient about 2 times greater than an ordinary turbine. However, the effect of the diffuser efficiency has not been implemented into blade element momentum yet, as well as the use of minimum pressure coefficient criterion to avoid cavitation during the optimization of the hydrokinetic chord along the blade. Hence, this work presents a novel approach to design diffuser-augmented hydro turbines considering the diffuser efficiency. Based on the blade element momentum, new expressions for the axial induction factor and thrust are obtained. In addition, both efficiency and load generated on a diffuser are considered to the extension of existing formulation to determine power coefficient in cases where diffuser losses are taken into account through efficiency (ηd) and area ratio (β). To assess the proposed model, a comparative evaluation of two different diffusers (flanged conical diffuser and flanged lens diffuser) is performed. Numerical and theoretical results are compared for a shrouded turbine equipped with 83% efficiency diffuser. The relative difference observed for the maximum power coefficient between the proposed model and an actuator disk model with diffuser is about 5.3%. For the hydro turbine with flanged conical diffuser, the mass flow rate is about 20% higher than for a bare turbine, while for the turbine with flanged lens diffuser the increase is only 2.4%. Also, for the flanged conical diffuser the power is increased by 53%. Furthermore, it is observed that the proposed blade element momentum with diffuser achieved good agreement with the numerical model, providing improved results compared to other models available in the literature. The optimization model of hydrokinetic chord shows relevant results in relation to the prevention of cavitation.
Acesso aberto (Open Access)
Abordagem para o desenvolvimento de um etiquetador de alta acurácia para o Português do Brasil
(Universidade Federal do Pará, 2011-10-21) DOMINGUES, Miriam Lúcia Campos Serra; FAVERO, Eloi Luiz; http://lattes.cnpq.br/1497269209026542
Part-of-speech tagging is a basic task required by many applications of natural language processing, such as parsing and machine translation, and by applications of speech processing, for example, speech synthesis. This task consists of tagging words in a sentence with their grammatical categories. Although these applications require taggers with greater precision, the state of the art taggers still achieved accuracy of 96 to 97%. In this thesis, corpus and software resources are investigated for the development of a tagger with accuracy above of that of the state of the art for the Brazilian Portuguese language. Based on a hybrid solution that combines probabilistic tagging with rule-based tagging, the proposed thesis focuses on an exploratory study on the tagging method, size, quality, tag set, and the textual genre of the corpora available for training and testing, and evaluates the disambiguation of new or out-of-vocabulary words found in texts to be tagged. Four corpora were used in experiments: CETENFolha, Bosque CF 7.4, Mac-Morpho, and Selva Científica. The proposed tagging model was based on the use of the method of transformation-based learning (TBL) to which were added three strategies combined in a architecture that integrates the outputs (tagged texts) of two free tools, Treetagger and -TBL, with the modules that were added to the model. In the tagger model trained with Mac-Morpho corpus of journalistic genre, tagging accuracy rates of 98.05% on Mac-Morpho test set and 98.27% on Bosque CF 7.4 were achieved, both of journalistic genres. The performance of the proposed hybrid model tagger was also evaluated in the texts of Selva Científica Corpus, of the scientific genre. Needs of adjustments in the tagger and in corpora were identified and, as result, accuracy rates of 98.07% in Selva Científica, 98.06% in the text set of Mac-Morpho, and 98.30% in the texts of the Bosque CF 7.4 have been achieved. These results are significant because the accuracy rates achieved are higher than those of the state of the art, thus validating the proposed model to obtain a more reliable part-of-speech tagger.
Acesso aberto (Open Access)
Uma abordagem para otimização do período de sensoriamento em rádio cognitivo com algoritmo genético multiobjetivo
(Universidade Federal do Pará, 2011-08-25) YOSHIOKA, Peterson Marcelo Santos; COSTA JÚNIOR, Carlos Tavares da; http://lattes.cnpq.br/6328549183075122
The spectral efficiency in networks based on cognitive radio (CR) technology can be compromised if the radio is used for a long time for the detection instead of data transmission. So it becomes necessary sensing schemes that have the purpose of obtaining the maximum possible use of spectrum, avoiding unnecessary sensing, as well as obtaining a minimum of interference in the transmission of the primary user due to incorrect detection of its transmission. In this paper, we propose the use of genetic algorithms for the adaptation of the sensing period. The goal is to obtain an optimal channels sensing period in order to maximize the discovery of spectrum opportunities and minimize the overhead due to the sensing. Most related works to this issue adopt fixed sensing overhead, not taking into account that some channels may have less tolerance to interference than others. The proposal presented in this work can adapt to the requirements of tolerance to interference with licensed channel by determining a period of sensing that optimizes the opportunities for any set amount of overhead. Our proposal achieves a gain up to 90% compared to nonoptimized techniques in terms of the number of opportunities found up to 40.9% gain in useful transmission and obtained a reduction in the time of interference of 66.83%. In addition, our proposal also achieves similar results to those obtained by an optimized proposal in the literature, with the advantage of allowing the adaptation of the sensing overhead.
Acesso aberto (Open Access)
Abordagem probabilística para caracterização do sistema de marcação de sequenciamento multiplex na plataforma ABI SOLID
(Universidade Federal do Pará, 2011-07-01) LOBATO, Fábio Manoel França; SANTANA, Ádamo Lima de; http://lattes.cnpq.br/4073088744952858
The next generation sequencers such as Illumina and SOLiD platforms generate a large amount of data, commonly above 10 Gigabytes of text files. Particularly, the SOLiD platform allows the sequencing of multiple samples in a single run (called multiplex run) through a marking system called Barcode. This feature requires a computational process for separation of data per sample, therefore, the sequencer provides a mixture of all samples in a single output. This process must be secure to avoid any harm that may scramble further analysis. In this context, this dissertation proposes development of a probabilistic model capable of characterizing the marking system used in multiplex sequencing. The results corroborate the adequacy of the model obtained, which allows, among other things, identify faults in some step in the sequencing process, adapt and develop new protocols for sample preparation, and assign a grade to the reliability of data generated and guide a filtering process that respects the characteristics of each sequence, without discarding sequences useful in an arbitrary manner.
Acesso aberto (Open Access)
Uma abordagem SDN para virtualização de redes
(Universidade Federal do Pará, 2016-11-25) PINHEIRO, Billy Anderson; ABELÉM, Antônio Jorge Gomes; http://lattes.cnpq.br/5376253015721742
The virtual SDN networks (vSDNs) have emerged from the association of virtualization and Software-Dened Networking (SDN), providing greater control and better use of network resources. Several studies have already shown the feasibility and benets of this approach. However, the issue still lacks solutions that can virtualize a network in a scalable, intuitive and simplied manner. Thus, this thesis proposes an SDN approach to network virtualization with the aim of reducing the limitations on vSDNs. Therefore, it is suggested to adopt in network virtualization the separation between data plans (distributed) and control (centralized), the global network view and use of ow abstraction to manage the communication between the dierent points. To support our proposition, three solutions were developed: the CIM-SDN (Common Information Model for Software-Dened Networking), to enable the use of formal representation of the new elements of vSDNs; The NVP (Network Virtualization Proxy), to provide greater scalability by separating the control plane into centralized and decentralized parts; And Graph Virtualization Layer (GVL), to provide greater use of abstractions between the hypervisor and controllers, thereby simplifying the understanding and use of the network. Proof of concept tests was carried out for the three proposed solutions, demonstrating the feasibility of the approach.
Acesso aberto (Open Access)
Absorção de gases da queima de combustíveis fósseis em torre de recheio estruturado utilizando lama vermelha
(Universidade Federal do Pará, 2013-03-11) SANTOS, Iara Ferreira; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968; SOUZA, Célio Augusto Gomes de; http://lattes.cnpq.br/0800747860976046
The production of alumina from the Bayer process produces 1-3 tons of waste per ton of aluminum. This residue is known red mud, compound of minerals insoluble in concentrated sodium hydroxide, hematite and other iron oxides, quartz and titanium oxides. The red mud has in its composition varied levels of NaOH, depending on the specific industrial plant used. The purpose of this study is to evaluate the process of absorption of gases from a boiler countercurrent with a suspension of red mud, in a spray tower and a packed column. Experiments were performed varying the type of absorption tower, temperature of the liquid phase and solids content in liquid phase to evaluate the reduction in content of gases of combustion in the output of absorption tower and pH variation with time of operation, it was possible to identify the time required for the occurrence of red mud neutralization, and also a reduction in the content of carbon dioxide, thereunto were performed measurements of the concentrations of gasesin the input and output packed column, and also measurements of temperature and pH. The absorption of CO2 existing in the gases of combustion for suspension of red mud occurs by the carbonation process, where the gas reacts with NaOH present in red mud, with water as catalyst. The results obtained after the experiments were satisfactory, and it was concluded that the process performed in absorption towers is efficient for pH reduction of red mud and reducing the content of CO2 freed to atmosphere, providing a double profit for the environment.
Acesso aberto (Open Access)
Absorção do dióxido de carbono por resíduo de bauxita em torres de absorção
(Universidade Federal do Pará, 2013-03-04) BOTELHO, Fernando Aracati; MACÊDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505; SOUZA, José Antônio da Silva; http://lattes.cnpq.br/6157348947425968
One of the most discussed environmental problems on the world scene today is global warming and its implications. Although the greenhouse effect is a natural phenomenon, the increase in emissions of gases such as CO2 from the combustion process may favor its aggravation. Following this line, there is interest in conducting research to minimize the release of this gas in the atmosphere. This work aims to study the process of absorption of carbon dioxide by aqueous phase of bauxite residue (soda and dissolved ions in solution) in spray tower and tower saddles random (both pilot scale), as well as check the pH change in this absorption process to both towers. Evaluate pH change and CO2 absorption capacity by considering the following variables: the type of absorption tower, using the supernatant as the absorbent means and the use of the suspension heated by resistances. The results showed that the suspension of bauxite residue absorbed significant amount of CO2, both the spray tower as the tower saddles. The average absorption rate was around 8.42% for the spray tower and 9.34% for the tower saddles. The ability carbonating the suspension of 27%-p was about 33.3 kg CO2 per tonne of waste and there was a substantial reduction of the alkalinity of the residue by reaction with gaseous effluents with a mean decrease of 4.0 and 3.5 pH units for the tower saddles and sprinkler respectively.
Acesso aberto (Open Access)
Ação do vento na estabilidade global efeitos de segunda ordem em estruturas de concreto armado na cidade de Belém-PA
(Universidade Federal do Pará, 2018-02-23) MEDEIROS, José Odilon Barros de; MACEDO, Alcebíades Negrão; http://lattes.cnpq.br/8313864897400179
Due to the exponential growth of urban populations, the need for space for housing has grown significantly. To meet these demands, increasingly tall and slender buildings are designed, always aiming at the need to reduce costs and raise profitable margin by the construction companies. New materials and methods of structural analysis are created and improved so that maximum performance and structural safety are extracted at the lowest cost. Thus, this dissertation aims to contribute to the studies concerning the analysis of global stability and evaluation of the effects of 2nd order in the structures, from the comparative analysis of stability parameters, with the premises described in NBR 6118 (2014). In relation to the ultimate limit state, the following coefficients were evaluated: α and γz - suggested by NBR 6118 (2014), as well as FAVt and 𝑅𝑀2𝑀1 - obtained by the CAD/TQS System. With regard to the service limit state, the results concerning the horizontal displacements at the top of the buildings were analyzed and compared with the normative limits. For this, computational modeling was performed representing nine distinct fictitious structures submitted to the actions of the usual project loads on residential buildings, according to the aspects of NBR 6120 (1980), besides the evaluation of the influence of the consideration of the wind loads in the mentioned models structures. As for the development of the structures, usual techniques of discretization were employed, using the finite element method, through the CAD/TQS program. From the results obtained, it was observed that in the higher structures the parameters related to the ELU and ELS exceeded the normative limits, and that the fact regarding the lack of consideration of the wind action in the structures can significantly compromise the behavior and structural safety, since the calculated 1st and 2nd order final efforts can be up to 41% lower in relation to the efforts calculated by applying the criteria described in NBR 6123 (1988), in turn causing undersized structures and consequently, leading such structures to results catastrophic, such as ruin through progressive collapse.
Acesso aberto (Open Access)
Acionamento vetorial por controlador fuzzy modo deslizante de motor de indução
(Universidade Federal do Pará, 2010-05-20) TEIXEIRA, Raphael Barros; BARRA JUNIOR, Walter; http://lattes.cnpq.br/0492699174212608; BARREIROS, José Augusto Lima; http://lattes.cnpq.br/1246564618922453
This work studies the technique of vector drive applied to three-phase induction motor (IM), using as the control strategy fuzzy control and sliding mode control in a setting here called Fuzzy Sliding Mode Controller (FSMC) . A dynamic model is developed at IM in variable ’d - q’ which led to an electromechanical model state space that exhibits strong nonlinearities . In this model the conditions that allow vector control decouple the torque and flux at IM, so that their dynamic behavior is similar to that observed in a DC machine are applied. In this condition, the proportional and integral type (PI) controllers are implemented to control motor speed and current loops, and computational simulations for tracking speed and load disturbance are carried out, which lead to satisfactory results from the point of view dynamic. In order to investigate the performance of nonlinear strategies in this approach the study of control technique the switching structure of the sliding mode type is displayed. A conventional sliding mode controller is implemented, where it appears that, despite the excellent dynamic performance of the occurrence of the phenomenon of ”chettering”precludes the application of this strategy in actual tests. Thus, FSMC control strategy is proposed, trying to associate the good result obtained with the dynamic sliding mode controller and the suppression of the chettering, which is achieved by defining a layer switching fuzzy type. The FSMC proposed controller is subjected to the same computational tests that the PI controller, leading to superior results to the latter the transient dynamic response, but with the presence of steady-state error. To attack this problem is implemented one of the strategies Fuzzy FSMC combination with the action of PI control, where the first seeks to operate in remote regions of the switching surface and the second seeks to introduce the effect of integral action near the surface. The results show the feasibility of the strategy in variable speed drive that demand high dynamic performance.
Acesso aberto (Open Access)
Aço inoxidável nanoestruturado produzido via soldagem a arco elétrico.
(Universidade Federal do Pará, 2021-07-08) LOAYZA, Cristhian Ricardo; BRAGA, Eduardo de Magalhães; http://lattes.cnpq.br/4783553888547500
Manufacturing methods of nanostructured stainless-steel composites (NSSC) have not yet been developed with industrial applicability. To overcome this shortage, the possibility of incorporating nanoparticles by electric arc welding was investigated, using a tubular rod filled with nanostructured flux composed of multi-walled carbon nanotubes (MWCNT) and 304L stainless steel particles. This flux was manufactured by two different methods: mechanical alloying (MA) and chemical treatment (CT) with hydrogen peroxide. The second showed more promising results using control of kinetic parameters of time and temperature, obtaining a lower degree of amorphous carbon, impurities, and crystalline defects, increasing their crystallinity and interaction of the nanotubes with the metallic matrix. MWCNT incorporation decreased the grain size by 64% when compared to the stainless-steel coating, possessing an austenitic matrix with carbide precipitation in the interdendritic spaces and grain boundaries. The microhardness increased 45% and the rate of erosion by vibratory cavitation decreased 64%, in relation to the AISI 304L coating. Additionally, XRD analyses showed a reduction of the γ{200} phase and a growth of γ{111} after the cavitation process. The method of manufacture of the nanocomposites proved to be economically viable and with the possibility of immediate application on a large scale.
Acesso aberto (Open Access)
Ações de eficiência energética em navios: estudo de caso e um navio patrulha da Marinha do Brasil
(Universidade Federal do Pará, 2016-08-26) AQUINO, Suzane Cruz de; MORAES, Hito Braga de; http://lattes.cnpq.br/5044859479302394; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
Due to growing concern about the environment, the IMO (International Maritime Organization), through MARPOL (International Convention for the Prevention of Pollution from Ships), has developed the first mandatory regulation of the area about the energy efficiency of ships aiming the reduction of greenhouse gases emissions and costs related to energy consumption. This dissertation proposes a methodology of energy efficiency measures in a patrol ship of the Navy of Brazil. The analyzed ship, the P-49 or Guarujá, is a 19 years old vessel just as almost all its equipments. The Guarujá is electrically a isolated propulsion system from the power generation, then the target of this research were those systems with the highest electricity demand: the lighting system, cooling, electric power generation, saving and cold storages. However, the information available above those systems have proven scarce, thus it was exploited only the bulbs and some compressors and fan motors. The actions proposed to equipment available verification were 1. the exchange of the reference case bulbs with LED lamps; and 2. replacing the engines with similar specimens of higher yield. They were analyzed financially and environmentally by RETScreen software, an important tool for energy efficiency and renewable sources studies developed by the Government of Canada; with the aid of PROCEL simulator, BD Motor, promoting greater focus on the engines due to its complexity and significance in the optimal functioning of the ship's systems. The actions proved viable, with the total turnaround time of two years, reducing emissions by 164 tCO2 in 20 years and saving about R$ 352,974.80 at the end of the project time, thus justifying their implementation.
Acesso aberto (Open Access)
Acompanhamento e avaliação de projetos através da monitoração de eventos em um ambiente de gestão de processos de software
(Universidade Federal do Pará, 2007-07-04) PAXIÚBA, Carla Marina Costa; REIS, Rodrigo Quites; http://lattes.cnpq.br/9839778710074372
One of the greatest challenges found in software project management nowadays is to know the true dimension of what is being managed. There are several concerns that are relevant to project managers with respect to the estimation of size, duration, and cost of a project. In this context researchs show that the minor part of the projects are completed on time, on budget, and with all the features and functions originally specified. The other projects are completed overbudget, late or fail. Software project and product management can reach a given level of efficacy and exactness only if certain measurements are made in order to make it possible to manage based on facts. This dissertation focuses on efficient project management process which must be guided by the international process improvement standards and through the use of metrics as a fundamental tool for an effective project management. The basic assumption is that, without the use of adequate metrics, the planning and monitoring of projects become empirical activities, based solely on the feeling and experience of the project manager. This work presents a proposal for projects monitoring through the extension of the event recording mechanism of the WebAPSEE process-centered software engineering environment. The mechanism is the base to provide software support to generate monitoring reports based on process improvement approaches like CMMI and the Brazilian MPS.BR. The proposal was evaluated through a critical analysis involving the monitoring of simulated project with the proposed tool.
Acesso aberto (Open Access)
Acoplamento de modos guiados em cabos de pares trançados utilizando antenas com simetria radial no cenário terabit DSL
(Universidade Federal do Pará, 2020-03-26) SOUSA, Brenda Penedo Tavares de; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
The development of data transmission standards and access technologies has always been linked to the need to supply high data rates. Thus, technologies already implemented, such as the DSL (Digital Subscriber Line) system that uses twisted pairs for transmission, have been adjusting to support this growing data demand. In DSL systems, the twisted pairs are used as a transmission line, using the transverse electromagnetic mode (TEM). However, the physical limitations of the twisted pair as a transmission line prevent the system from achieving higher rates, needed to support fifth generation (5G) applications. Recently, it was proposed to use other transmission modes in the twisted pair, the higher order guided modes, as an alternative for this structure to be able to support transmission rates of the order of Terabits per second, having been termed as the Terabit DSL technology (TDSL). However, one of the challenges for this implementation is the coupling of the guided modes in the twisted pair, since they are not widely explored in the context of the propagation of higher-order guided modes, as simpler waveguides, such as Sommerfeld and Goubau. In this scenario, this dissertation aims to evaluate the coupling of the radiated signal between an antenna with radial propagation and the twisted pair cable, analyzing the electromagnetic behavior of structures. Considering that the twisted pair cable does not have a closed analytical model for the behavior of higher order modes, which propagate along these structures, all the results were obtained from numerical simulations in the software HFSS (High Frequency Structure Simulator).These results are in terms of the scattering parameter of the antenna and the electromagnetic field in the cable, making it possible to evaluate the coupling efficiency, the signal guidance and to predict the transmission rate available to users. The results obtained showed that the coupling between the antenna and the unshielded twisted pair cable reached levels of up to 83.83 % at frequencies of 0.15 THz, demonstrating a high coupling efficiency when compared to simpler scenarios in the literature, reaching levels on average 67 %. It was found that the use of these cables for data transmission is effective, managing to deliver rates of up to 1.737 Tbps in cables of up to 10 meters, while the rate forecasts for the TDSL scenario that consider the 100 % coupling reach levels of 2.013 Tbps.
Acesso aberto (Open Access)
Adaptação da metodologia da integração contínua na estratégia de desenvolvimento de produtos de software em empresas de economia mista de tecnologia – estudo de caso
(Universidade Federal do Pará, 2021-09-22) SOUZA, Renato Borges de; NASCIMENTO, Manoel Henrique Reis; http://lattes.cnpq.br/0850846128967798
The continuous integration methodology is a broad field that deals with the availability and publication of system codes, which aims to help associations to accelerate their development and delivery of software resources, without compromising quality. This approach becomes extremely important for speed in product deliveries. The main focus of this article is to promote the adaptation of this methodology by aligning it with the software product development strategy, in order to improve organizational results, through waste reduction, with knowledge of the end-to-end process. A case study was proposed to illustrate an execution of this process. Where, first, the mapping and analysis of the system development process and current portfolio management in the company was carried out, identifying its problems, and then a future process design was proposed, promoting the integration between the parts. This process will help the company to deliver products that fit the organizational strategy.