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- ItemA adoção das licitações sustentáveis nas Companhias Docas do Brasil e sua prática na Companhia Docas do Espírito Santo(Universidade Federal do Espírito Santo, 2017-03-14) Falcão, Maria Elisa de Freitas; Silva Filho, Alvim Borges da; Costa, Lourenço; Felipe, Ednilson SilvaThe sustainable procurement is created by including sustainable criteria in the documents that compose a bidding, consisting in a mechanism to promote the sustainable development. The basis of its existence is on Chapter 4 of Agenda 21 and for its adoption there is the Normative Instruction N°. 01/2010. Its application is extended for all public agencies and companies, including public ports, which have a large influence on the national economy, so identify instruments and criteria used, its effectiveness and possibilities for improvementcan contribute for the theme comprehension. Therefore, were made researching in Dock Companies websites; analyzing the published bidding notices in 2015; interviews; and case study of Dock Company of Espírito Santo (Codesa). Of eight Companies investigated, five have regulation and only three made it available in their websites. Also five made their bidding notices available in their website, which analysis pointed that the majority of sustainable criteria researched presents low representativity, except the requirement of not hiring employees under the age of 18. At the interviews, conducted in seven Companies, the legal sectors and the Bid Committees was appointed by all of them as responsible for elaborating the bids. About the internal regulation, two have affirmed to have it, three that it is in development and two that there is nothing on it. The case study demonstrated that the internal regulation proposes criteria for various types of product acquisition and contracting services; and the interviews pointed that was not offered any training about the theme and that the main barriers are the lack of commitment of the senior management and the lack of environmental awareness of the employees. Thus, there is in terms of the current state of sustainable procurements in port sector, the level of adherence is good, but the level of effective implementation is low. To improve its adherence it is required an internal regulation that regulates the inclusion of sustainable criteria containing responsibility attributions, being well publicized and accompanied by training.
- ItemA aplicação da Lei 9.966/2000 na prevenção e controle da poluição por óleo nos portos da costa marítima do Espírito Santo : estudo do Terminal Norte Capixaba(Universidade Federal do Espírito Santo, 2017-12-06) Amorim, Jader Luiz; Santos, Glicia Vieira dos; Campos, Adriana Fiorotti; Ferreira, Dirce Nazaré de AndradeThe occurrence of oil spill incidents at sea in different countries have led for the development of systems to prevent oil pollution in marine waters. In Brazil, the Law n. 9.966/2000 is the main regulatory instrument on this matter. However, there are few studies with regard to this Law's applicability in a way that may contribute to a thorough investigation of the factors that lead to these incidents inside the Brazilian territory. In this context, the present study aimed to answer the following question: the oil pollution control and prevention system as mentioned in the Law n. 9.966/2000 is being applied effectively? In this way, a bibliographical and documentary research was conducted in order to investigate if the Law's requisites on prevention and control were being applied in the period from 2005 to 2014, in a sea terminal that moves oil in the state of Espírito Santo. So, the monitoring and control measures adopted by the designated environmental agency were verified; the data regarding oil spillage incidents taken place in the Terminal Norte Capixaba were checked; the penalties applied by the environmental agency and also the preventive and response actions shown by the company when undergoing oil spillage incidents at sea were analyzed. This research brings the conclusion that there is effort being made by the environmental agency for the application of preventive and control instruments established by the Law. However, company´s lack of compliance with legal deadlines allied to delayed analyses by the environmental agency involved may significantly result in low efficacy towards oil pollution prevention at sea.
- ItemA brain-computer interface architecture based on motor mental tasks and music imagery(Universidade Federal do Espírito Santo, 2013-08-30) Benevides, Alessandro Botti; Bastos Filho, Teodiano Freire; Sarcinelli Filho, Mário; Ferreira, André; Frizera Neto, Anselmo; Conci, Aura; Tierra Criollo, Carlos JulioThis present research proposes a Brain-Computer Interface (BCI) architecture adapted to motor mental tasks and music imagery. For that purpose the statistical properties of the electroencephalographic signal (EEG) were studied, such as its probability distribution function, stationarity, correlation and signal-to-noise ratio (SNR), in order to obtain a minimal empirical and well-founded parameter system for online classification. Stationarity tests were used to estimate the length of the time windows and a minimum length of 1.28 s was obtained. Four algorithms for artifact reduction were tested: threshold analysis, EEG filtering and two Independent Component Analysis (ICA) algorithms. This analysis concluded that the algorithm fastICA is suitable for online artifact removal. The feature extraction used the Power Spectral Density (PSD) and three methods were tested for automatic selection of features in order to have a training step independent of the mental task paradigm, with the best performance obtained with the Kullback-Leibler symmetric divergence method. For the classification, the Linear Discriminant Analysis (LDA) was used and a step of reclassification is suggested. A study of four motor mental tasks and a non-motor related mental task is performed by comparing their periodograms, Event-Related desynchronization/synchronization (ERD/ERS) and SNR. The mental tasks are the imagination of either movement of right and left hands, both feet, rotation of a cube and sound imagery. The EEG SNR was estimated by a comparison with the correlation between the ongoing average and the final ERD/ERS curve, in which we concluded that the mental task of sound imagery would need approximately five times more epochs than the motor-related mental tasks. The ERD/ERS could be measured even for frequencies near 100 Hz, but in absolute amplitudes, the energy variation at 100 Hz was one thousand times smaller than for 10 Hz, which implies that there is a small probability of online detection for BCI applications in high frequency. Thus, most of the usable information for online processing and BCIs corresponds to the α/µ band (low frequency). Finally, the ERD/ERS scalp maps show that the main difference between the sound imagery task and the motor-related mentaltasks is the absence of ERD at the µ band, in the central electrodes, and the presence of ERD at the αband in the temporal and lateral-frontal electrodes, which correspond tothe auditory cortex, the Wernickes area and the Brocas area.
- ItemA commitment-based reference ontology for service: harmonizing service perspectives(Universidade Federal do Espírito Santo, 2014-12-10) Nardi, Julio Cesar; Almeida, João Paulo Andrade; Falbo, Ricardo de Almeida; Pires, Luiz Ferreira; Amorim, Fernanda Araújo Baião; Guizzardi, Renata Silva Souza; Barcellos, Monalessa PeriniNowadays, the notion of service has been widely adopted in the practice of economic sectors (e.g., Service, Manufacturing, and Extractive sectors), as well as, in the research focus of various disciplines (e.g., Marketing, Business, and Computer Science). Due to that, a number of research initiatives (e.g., service ontologies, conceptual models, and theories) have tried to understand and characterize the complex notion of service. However, due to particular views of these disciplines and economic sectors, a number of different characterizations of service (e.g., “service as interaction”, “service as value co-creation”, and “service as capability / manifestation of competence”, among others) have been proposed. The existence of these various non-harmonized characterizations, and the focus on a terminological debate about the “service” concept, instead of about the service phenomena from a broad perspective, make the establishment of a unified body of knowledge for service difficult. This limitation impacts, e.g., the establishment of unified conceptualization for supporting the smooth alignment between Business and IT views in service-oriented enterprise architecture (SoEA), and the design and usage of service modeling languages. In this thesis we define a theoretical foundation for service based on the notion of service commitment and claims as basic elements in the characterization of service relations along service life cycle phases (service offer, service negotiation, and service delivery). As discussed in this work, this theoretical foundation is capable of harmonizing a number of service perspectives found in the literature. Such theoretical foundation is specified in a well-founded core reference ontology, named UFO-S, which was designed by adopting a sound ontological engineering apparatus (mainly, a wellfounded ontology representation language, OntoUML, and approaches of model verification and model validation). As a kind of “theory”, UFO-S was applied in the analysis of SoEA structuring principles in order to define a “commitment-based SoEA view”, which remarks social aspects inherent in service relations usually underexplored in widely adopted service-oriented approaches (such as SOA-RM by OASIS, ITIL, and ArchiMate). Based on this, UFO-S was also applied in an ontological analysis of service modeling at ArchiMate’s Business layer. Such ontological analysis showed some limitations concerned to semantic ambiguity and lack of expressiveness for representing service offerings (and type thereof) and service agreements in SoEA. In order to address these limitations, three service modeling patterns (service offering type pattern, service offering pattern, and service agreement pattern) were proposed taking as basis UFO-S. The usefulness of these patterns for addressing these limitations was evidentiated by means of an empirical evaluation. Finally, we can say that, beyond offering a broad and well-founded theoretical foundation for service able to harmonize service perspectives, UFO-S presented benefits as a reference model in the analysis of SoEA structuring principles, and in the (re)design of service modeling languages.
- ItemA eficiência energética do consumo de combustível em uma ferrovia heavy haul(Universidade Federal do Espírito Santo, 2017-05-19) Cabral, Eric Wilson Santos; Cruz, Marta Monteiro da Costa; Morais Neto, Gregório Coelho de; Salles, José Leandro Félix; Fardin, Jussara FariasIn the Brazilian scenario from 2001 to 2015, the value of diesel rose 210%, which directly reflects the costs of the companies in the transportation segment. Among the challenges in the daily life of heavy haul railways is the cost reduction, which can be achieved by improving energy efficiency. It is then necessary to act effectively to seek the reduction of the ratio of liters of fuel consumed per Gross Ton kilometers multiplied by thousand (L/KTKB). This study aimed to identify which controlled variables in the railroads have a correlation with KTKB. Statistical analysis and continuous rail simulation tools were used, within scenarios defined according to the operational reality of a heavy haul railroad. The variables analyzed were the average weight per wagon, the number of stops of trains, average kilometers between stops (KMEP) and the type of train formation (TF). The possibility of saving with the change in the operational procedure of stops of the trains for changes of drivers was evaluated. In addition to the simulations, the fuel volume in the tank began to be monitored in real time, a system of shutdown and automatic locomotive activation was implemented and the operators were made aware of the reduction of fuel consumption. As a result, it was observed that the energy efficiency of the railway improved by 13% over the period 2014 to 2016, with a reduction in diesel consumption of 1.93 L/KTKB to 1.68 L/KTKB.
- ItemA energia solar fotovoltaica em sistemas conectados à rede elétrica no Brasil : aspectos econômicos e políticas de incentivo(Universidade Federal do Espírito Santo, 2017-08-08) Scarpati, Cynthia de Barros Lima; Campos, Adriana Fiorotti; Santos, Glícia Veira dos; Salles, Alexandre Ottoni Teatiniabstract
- ItemA fairness-focused spectrum assignment algorithm for elastic optical networks(Universidade Federal do Espírito Santo, 2016-09-27) Tessinari, Rodrigo Stange; Garcia, Anilton Salles; Waldman, Hélio; Martins, Joberto Sérgio Barbosa; Resendo, Leandro Colombi; Segatto, Marcelo Eduardo Vieira; Paiva, Marcia Helena MoreiraIn the past few years, Elastic Optical Networking (EON) emerged as the next generation core network technology, intended to surpass Wavelength-Division Multiplexing (WDM) weaknesses and limitations. WDM is the most successful and widely used technology in the backbone of the optical networks. However, in recent years Internet traffic in the core network has been doubling almost every two years, and predictions indicate that it will continue to exhibit exponential growth due to emerging applications such as high-definition and real-time video communications. To keep pace with the always greater demand for bandwidth, EON relies on Optical Orthogonal Frequency Division Multiplexing (OOFDM) and advanced modulation technologies which enhance spectral efficiency and flexibility. OOFDM allows the aggregation of multiple sub-carriers to form super-channels, thus changing the paradigm of the network from fixed-size WDM channels to variable-sized EON channels that can reduce spectrum waste up to 60%. EON presents several other benefits such as high spectral and energy efficiency and flexible bandwidth adaptation over time. Despite all benefits, no technology is perfect, and the added EON efficiency and flexibility comes at the price of increased complexity and new problems, such as spectrum fragmentation and service unfairness. A considerable amount of work has been done on both fragmentation and unfairness problems, introducing a broad range of solutions, which raises the following question: "how to compare existent solutions and how to identify which one is better suited for the required scenario?" In this context, it is presented the first contribution of this Doctoral Thesis, ElasticO++, an Elastic Optical Network Simulation Framework for OMNeT++. ElasticO++ is a framework created to enable testing a whole range of routing, modulation, spectrum assignment, defragmentation algorithms, parameters, and topologies. At present, the proposed framework is the first software available capable of working with fragmentation and defragmentation in dynamic network scenarios. The flexibility offered on the proposed tool allows both academia and industry to develop new algorithms and techniques for Elastic Optical Networks. The second contribution of this Doctoral Thesis is the Zone-Based Spectrum Assignment Algorithm. The proposed algorithm is an attempt to solve the unfairness and fragmentation problems, taking advantage of the spectrum management concept. In this Doctoral Thesis, it is presented two versions of the technique: the static version and the dynamic version. The static version is intended to be used in cases where the information regarding the nature of the network traffic is known beforehand, whereas the dynamic version was developed as a solution in cases in which absolutely no information is known.
- ItemA framework to support the assignment of active structure and behavior in enterprise modeling approaches(Universidade Federal do Espírito Santo, 2012-08-31) Arpini, Rômulo Henrique; Almeida, João Paulo Andrade; Falbo, Ricardo de Almeida; Araujo, Renata Mendes deThe need to relate the various architectural domains captured in partial descriptions of an enterprise is addressed in virtually all enterprise modeling approaches. One of these domains, namely that of organizational behavior, has received significant attention in recent years in the context of business process modeling and management. Another important domain, that of organizational structure is strongly inter-related with the process domain. While the process domain focuses on how the business process activities are structured and performed, the organizational structure domain focuses on who performs these activities, i.e., which kinds of entities in an organization are capable of performing work. Given the strong connection between the organizational behavior and organizational resources, we argue that any comprehensive enterprise modeling technique should explicitly establish the relations between the modeling elements that represent organizational behavior, called here behavioral elements, and those used to represent the organizational resources (organizational actors) involved in these activities, called here active structure elements. Despite the importance of the relations between these architectural domains, many of the current enterprise architecture and business process modeling approaches lack support for the expressiveness of a number of important active structure allocation scenarios. This work aims to overcome these limitations by proposing a framework for active structure assignment that can be applied to enterprise architecture and business process modeling approaches. This framework enriches the expressiveness of existing techniques and supports the definition of precise active structure assignments. It is designed such that it should be applicable to a number of enterprise architecture and business process modeling languages, i.e., one should be able to use and apply different (enterprise and business process) modeling languages to the framework with minor changes.
- ItemA general purpose conceptual model for crowdsourcing projects(Universidade Federal do Espírito Santo, 2018-08-07) Assis Neto, Fábio Ribeiro de; Santos, Celso Alberto Saibel; Pereira Filho, José Gonçalves; Santos, Vaninha Vieira dosCrowdsourcing is a method that employs people to process input data to solve a computationally complex problem, such as generating a large dataset of annotated images, audio transcriptions or video scene descriptions. In this approach, people select tasks and produce individual results according to a list of steps that leads to an efficient solution. Then, every single result must be collected, interpreted, and integrated by a platform or system supporting the crowdsourcing process. Considering that the first studies regarding this field of study were done by means of experimenting and observing platforms and systems that popularized this method. Given that, pertinent questions are: (i) besides platforms and systems, what are the essential elements that compose a crowdsourcing project?; (ii) how the humans are guided through the steps for solving the proposed problem?; (iii) how to ensure the quality of the results produced in all stages of a project?; and (iv) are there guidelines or models in the state-of-the-art to help newcomers creating their own projects? Aiming to answer these questions, a systematic literature review based on the viewpoint of individuals that seek to solve problems using the crowdsourcing method was performed during this MSc dissertation, thus stating that this domain lacks general guidelines and models that leverage the essential elements of this kind of project, as well as its relationships and descriptions. Therefore, this dissertation aims to present a set of tendencies and guidelines related to crowdsourcing project and propose a general-purpose conceptual model that represent the essential elements involved and how they relate in this kind of project, in a way that is possible to instantiate and expand this model to supply specific needs of individual projects. Furthermore, the proposed model was applied during the planning and execution stages of a crowdsourcing project designed locally.
- ItemA Human-Machine Interface Based on Eye Tracking for Controlling and Monitoring a Smart Home Using the Internet of Things(Universidade Federal do Espírito Santo, 2019-02-20) Bissoli, Alexandre Luís Cardoso; Encarnação, Lucas Frizera; Bastos Filho, Teodiano Freire; Adams, Kimberly; Krishnan, Sridhar; Villa Parra, Ana Cecilia; Ferreira, AndréPeople with severe disabilities may have difficulties when interacting with their home devices, due to the limitations inherent to their disability. Simple home activities may be even impossible for this group of people. Although many works have been devoted to proposing new assistive technologies to improve the lives of people with disabilities, some studies have found that the abandonment of such technologies is quite high. In this sense, this work presents a new and useful assistive system based on eye tracking for controlling and monitoring a smart home based on internet of things, which was developed following concepts of user-centered design and usability. With this system, a person with severe disabilities was able to control everyday equipment of her residence, such as lamps, television, fan and radio. In addition, her caregiver was able to monitor remotely, by internet, her use of the system in real time. Additionally, the user interface developed here has some functionalities that allowed improving the usability of the system as a whole. The experiments were divided into two steps. In the first step, the assistive system was assembled in an actual home, where tests were conducted with 29 participants without disabilities (group of able-bodied participants). In the second step, the system was tested with online monitoring, for seven days, by a person with severe disability (end-user), in her own home, not only to increase convenience and comfort, but also so that the system could be tested where it would in fact be used. At the end of both steps, all the participants answered the SUS questionnaire, which showed that both the group of able-bodied participants and the person with severe disabilities evaluated the assistive system with a mean of 89.9 and 92.5, respectively.Keywords:Human-Machine Interface (HMI); Human-Computer Interaction (HCI); Smart Home; Eye Tracking; Assistive Technology; Usability Evaluation; User-Centered Design (UCD); Home Automation; Internet of Things (IoT).
- ItemA influência da envoltória no consumo energético em edifícios comerciais artificialmente climatizados na cidade de Vitória-ES(Universidade Federal do Espírito Santo, 2012-04-03) Bernabé, Ana Carolina Alves; Alvarez, Cristina Engel de; Gama, João Luiz Calmon Nogueira da; Fardin, Jussara Farias; Multfarth, Roberta Consentino KronkaThe deployment of cities have motivated the proposition of building more and more vertical in order to meet the demands for urban densification. Over time, the vertical development was linked to new technologies that initially came to give to the architect more projectual freedom. However, the possibility of reproducing models referenced in a modern and international style, led some professionals to neglect the close relation between architecture and the environment that it is inserted, leaving to artificial systems the role of ensuring thermal comfort for the users. However, the new energy scenario brought a reflection of the high demand for energy consumption in buildings, resulting in discussions, studies and development of a new reality, based on the concepts of energy efficiency. It is within this perspective that the research falls. The goal is to identify how and how much some strategies applicable to architectural envelope and inserted in the climate context of Vitória-ES, can influence the energy consumption of commercial buildings verticalized and artificially conditioned. The methodology proposed 108 models parameterized matching values for five investigated variables, they are: orientation, window wall ratio, solar factor, the existence of sun protection and absorptance of the opaque surface. These buildings were modeled after a reference building, so all other variables were controlled. As output data for the simulations we have established the final energy consumption. The analysis of these results was established in two ways. The first included the classification of the models that have achieved the level of efficiency through the procedure established by RTQ-C. The second involves the analysis of general and individual influence of each variable, and the potential for increase and reduction of energy expenditure of each one. As a result, it was found that changing the variables investigated led to a reduction of up to 27.88% in final consumption for the proposed model. The investigative tests suggest an even greater potential savings face to the most appropriate use of louvers and indicate the importance of lighting control in some cases.
- ItemA model-based graphical editor for supporting the creation, verification and validation of OntoUML conceptual models(Universidade Federal do Espírito Santo, 2010-02-05) Benevides, Alessander Bott; Almeida, João Paulo Andrade; Guizzardi, Giancarlo; Falbo, Ricardo de Almeida; Costa, Mateus Conrad Barcellos daThis thesis presents a model-based graphical editor for supporting the creation, verification and validation of conceptual models and domain ontologies in a philosophically and cognitively well-founded modeling language named OntoUML. The editor is designed in a way that, on one hand, it shields the user from the complexity of the ontological principles underlying this language. On the other hand, it reinforces these principles in the produced models by providing a mechanism for automatic formal constraint verification, hence ensuring that the created models will be syntactically correct. Assessing the quality of conceptual models is key to ensure that conceptual models can be used effectively as a basis for understanding, agreement and construction of information systems. For this reason, the editor is also capable of automatic generation of model instances by transforming these models into specifications in the logic-based language Alloy. As the generated Alloy specifications include the modal axioms of the foundational ontology underlyingOntoUML, named Unified Foundational Ontology (UFO), then the automatically generated instances will present modal behaviour while being dynamically classified, thereby supporting the validation of the modal meta-properties of the OntoUML types.
- ItemA model-driven approach to the conceptual modeling of situations: from specification to validation(Universidade Federal do Espírito Santo, 2015-10-28) Sobral, Vinicius Marchandt; Costa, Patrícia Dockhorn; Almeida, João Paulo Andrade; Pires, Luís Ferreira; Pereira Filho, José GonçalvesThe modeling of situation types for context-aware applications, also called situationaware applications, is, on the one hand, a key task to the proper functioning of those applications. On the other hand, it is also a hard task given the complexity and the wide range of possible situation types. Aiming at facilitating the representation of those types of situations at design-time, the Situation Modeling Language (SML) was created. This language is based partially on rich ontological theories of conceptual modeling and is accompanied by a platform for situation-detection at runtime. Despite the benefits of the availability of this suitable infrastructure, the definition of situation types, being a non-trivial task, can still pose problems that are hardly detected by modelers by manual model inspection. This thesis aims at improving and facilitating the definition of situation types in SML by proposing: (i) the integration between the language and the ontological theories of conceptual modeling by using the OntoUML language, with the purpose of increasing the expressivity of situation type models; and (ii) an approach for the validation of situation type models using a lightweight formal method, aiming at increasing the correspondence between the created models’ instances and the modeler’s intentions. Both the integration and the validation are implemented in a tool for specification, verification and validation of ontologically-enriched situation types.
- ItemA model-predictive motion planner for the IARA autonomous car(Universidade Federal do Espírito Santo, 2017-11-23) Cardoso, Vinícius Brito; Badue, Claudine; Souza, Alberto Ferreira de; Santos, Thiago Oliveira dos; Osório, Fernando SantosIn this work, we present the Model-Predictive Motion Planner (MPMP) of the Intelligent Autonomous Robotic Automobile (IARA). IARA is a fully autonomous car that uses a path planner to compute a path from its current position to the desired destination. Using this path, the current position, a goal in the path and a map, IARAs MPMP is able to compute smooth trajectories from its current position to the goal in less than 50 ms. MPMP computes the poses of these trajectories so that they follow the path closely and, at the same time, are at a safe distance from occasional obstacles. Our experiments have shown that MPMP is able to compute trajectories that follow precisely a path produced by a human driver (distance of 0.15m in average) while smoothly driving IARA at speeds of up to 32.4 km/h (9 m/s).
- ItemA multiagent architecture to multilingual interaction(Universidade Federal do Espírito Santo, 2017-08-11) França, Eduardo dos Santos; Tavares, Orivaldo de Lira; Menezes, Crediné Silva de; Castro Junior, Alberto NogueiraThis dissertation presents a virtual environment specially constructed with resources to aid in the communication between speakers of different languages, aimed at enabling interaction in textual environments between pairs or groups of people, within learning communities that do not have a common language. In this environment there is a digital agent (or bot) that uses communication strategies to assist the interlocutors in the understanding of messages in foreign languages, and may also define technical terms, regionalisms and expressions according to dictionaries and services used. The environment resources were focused on synchronous interactions, but can also be used in asynchronous interactions with some adaptations. In addition to supporting such communication between speakers of different languages, interactions are stored for research on the effects of agents, strategies, and resources on communication
- ItemA neural-based model predictive control to tackle steering delay of the IARA autonomous car(Universidade Federal do Espírito Santo, 2017-09-04) Guidolini, Rânik; Gonçalves, Claudine Santos Badue; Santos, Thiago Oliveira dos; Wolf, Denis FernandoIn this work, we propose a Neural Based Model Predictive Control (N-MPC) approach to tackle delays in the steering plant of autonomous cars. We examined the N-MPC approach as an alternative for the implementation of the Intelligent and Autonomous Robotic Automobile (IARA) steering control subsystem. For that, we compared the standard solution, based on the Proportional Integral Derivative (PID) control approach, with the N-MPC approach. The PID steering control subsystem works well in IARA for speeds of up to 25 km/h. However, above this speed, IARA’s Steering Plant delays are too high to allow proper operation with a PID approach. We tried and modeled the IARA’s Steering Plant using a neural network and employed this neural model in the N-MPC approach. The N-MPC approach outperformed the PID approach by reducing the impact of IARA’s Steering Plant delays and allowing the autonomous operation of IARA at speeds of up to 37 km/h – an increase of 48% in the maximum stable speed.
- ItemA novel approach of independent brain-computer interface based on SSVEP(Universidade Federal do Espírito Santo, 2016-09-01) Tello, Richard Junior Manuel Godinez; Ferreira, André; Müller, Sandra Mara Torres; Bastos Filho, Teodiano Freire; Ciarelli, Patrick Marques; Lima, Eduardo Roncon de; Sá, Antônio Maurício Miranda deOver the past ten years, Brain Computer Interfaces (BCIs) based on Steady- State Visual Evoked Potentials (SSVEP) have attracted the attention of many researchers due to the promissory results and the high accuracy rates achieved. This type of BCI provides to people with severe neuromotor difficulties the possibility to communicate with the world around them using visual attention modulation to blinking lights at a given frequency. This thesis aiming at developing a new approach of Independent BCI, in which users are not required to perform neuromuscular tasks to select visual targets, a feature that distinguishes it from traditional SSVEP-BCIs. Thus, people with severe motor disabilities as Amyotrophic Lateral Sclerosis (ALS) have a new alternative channel to communicate with the world around them using brain signals. Several contributions were done in this thesis, such as: improvement of the feature extractor called Multivariate Synchronization Index (MSI) for detecting evoked potentials; development of a new method for detecting evoked potentials through correlating multidimensional models (tensors); a first study on the influence of colored stimuli in SSVEPs detection using LEDs; the development of the concept of Compressive sensing applied to SSVEPs; and, finally, the development of a novel independent BCI under an approach named Figure-Ground Perception (FGP)
- ItemA novel cooperative algorithm for clustering large databases with sampling(Universidade Federal do Espírito Santo, 2012-07-30) Fabris, Fábio; Varejão, Flávio Miguel; Alvarenga, Arlindo Gomes de; Barbosa, Hélio José Corrêa; Rodrigues, Alexandre LoureiroClustering is a recurrent task in data mining. The application of traditional heuristics techniques in large sets of data is not easy. They tend to have at least quadratic complexity with respect to the number of points, yielding prohibitive run times or low quality solutions. The most common approach to tackle this problem is to use weaker, more randomized algorithms with lower complexities to solve the clustering problem. This work proposes a novel approach for performing this task, allowing traditional, stronger algorithms to work on a sample of the data, chosen in such a way that the overall clustering is considered good.
- ItemA novel stimulation paradigm for a brain-computer interface based on SSVEP(Universidade Federal do Espírito Santo, 2015-11-30) Atencio, Anibal Cotrina; Ferreira, André; Bastos Filho,Teodiano Freire; Frizera Neto, Anselmo; Sarcinelli Filho, Mario; Krohling, Renato Antônio; Sá, Antonio Mauricio Ferreira Leite Miranda deBrain-computer interfaces (BCIs) are systems that provide a direct connection between users’ brain signals and a computer, generating an alternative channel of communication that does not involve the traditional way as muscles and nerves. They help to restore or replace useful functions of people with paralysis. For instance, BCI systems based on SSVEP (SSVEP-BCI) present a set of stimuli flickering at different frequencies to the users, detect which stimulus is being gazed and associate this information to commands that can be used to control a robotic wheelchair, an exoskeleton, or a speller. Nowadays, SSVEP-BCIs are being widely used due to the high SNR of their response that is achieved when the target stimulus is brought to the center of the user’s field of view. Paradoxically, it is their main disadvantage because bringing a stimulus to the center of the field of view demands muscular activity making them not suitably for paralyzed people who cannot control their head, neck and/or eyeball movements for redirecting their gaze. In optical systems, the range of distance near the point of focus where objects are perceived sharp is referred as Depth-of-field; objects outside this region are defocused and blurred. The mechanism of the visual system that adjusts the eye focal length for focusing does not demand neck, head and/or eyeball movements. Furthermore, ophthalmology studies state that the amplitude and the latency of visual evoked potentials are affected by defocusing. In this context, this Thesis proposes a novel SSVEP-BCI paradigm, in which two stimuli are presented together in the center of the user’s field of view but at different distances from him, ensuring that if one stimulus is focused on, the other one is non-focused, and vice versa; with the aim of providing an alternative way of sending commands through a stimuli selection by a focusing mechanism. In this sense, first, a model of VEP generation for two stimuli is introduced and the hypothesis that distinguishable SSVEP can be elicited by the focused stimulus, regardless of the non-focused stimulus is also present, is tested by employing the SFT-based ORD. Next, a demodulation method based in LPF and HPF is proposed for the case in that two stimuli are present in the field of view; and spatial-temporal retinal response for flickering stimuli is described by using PSF and NPSF functions. Finally, CCA, PSDA, LASSO with EEG signals re-referenced at Pz and CAR are employed to detect the SSVEP pattern. Accuracy rate, Kappa coefficient, AUC, and ITR are used to evaluate the detection performance. As a result of the hypothesis test, the absence of evoked potentials due to a focused stimulus, when a non-focused stimulus is also present was rejected in most of the cases. In SSVEP detection experiments, an average accuracy rate of 0.93 was achieved for a time window of 7s and for eight healthy subjects who were asked to focus on just one stimulus at a time.
- ItemA numerical and statistical approach to estimate state variables in flow-accelerated corrosion problems(Universidade Federal do Espírito Santo, 2014-08-29) Moura, Bruno Furtado de; Macêdo, Marcelo Camargo Severo de; Silva, Wellington Betencurte da; Martins, Márcio Ferreira; Colaço, Marcelo JoséSequential Monte Carlo (SMC) or Particle Filter Methods became very popular in the last few years in the statistical and engineering communities. Such methods have been widely used to deal with sequential Bayesian inference problems in several fields. SMC Methods are an approximation of sequences of probability distributions of interest, using a large set of random samples, named particles there are propagated along time with a simple Sampling Importance distribution, SI, and re-sampling techniques as well. In this work we applied two Bayesian filters to a state estimation problem involving the corrosion amount-time in a contraction-expansion geometry and compared with Computational Fluid Dynamics (CFD) results. The model adopted to estimate the mass losses is based on a double resistance due to the oxygen diffusion toward the wall through the hydrodynamic boundary layer and the oxide layer. Mass loss data over time is obtained from the literature as well. The main objective of this work is to discuss and compare the performance of the following filters: Sampling Importance Re-sampling Filter (SIR Filter) and Auxiliary Sampling Importance Re-sampling Filter (ASIR Filter) in estimation of the mass losses. Also, it is discussed the influence of the corrosion products. Best results in corrosion damage estimation were obtained using the ASIR Filter.