Informática

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Programa de Pós-Graduação em Informática

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Agora exibindo 1 - 20 de 325

A 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 Perini
Nowadays, 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.
A conceptual architecture and a framework for dealing with variability in mulsemedia systems
(Universidade Federal do Espírito Santo, 2019-12-03) Saleme, Estevao Bissoli; Santos, Celso Alberto Saibel; https://orcid.org/0000000232875843; http://lattes.cnpq.br/7614206164174151; https://orcid.org/0000000318563824; http://lattes.cnpq.br/8757661847246456; Pereira Filho, Jose Goncalves ; https://orcid.org/0000-0002-8056-3836; http://lattes.cnpq.br/8265854560095874; Martinello, Magnos; https://orcid.org/0000-0002-8111-1719; http://lattes.cnpq.br/7471111924336519; Saade, Debora Christina Muchaluat; https://orcid.org/0000-0002-1233-9736; http://lattes.cnpq.br/2448703093928632
The increasing interest in digital immersive experiences has drawn the attention of researchers into understanding human perception whilst adding sensory effects to multimedia systems such as VR (Virtual Reality) and AR (Augmented Reality) applications, multimedia players, and games. These so-called mulsemedia—multiple sensorial media—systems are capable of delivering wind, smell, vibration, among others, along with audiovisual content with the aim of enhancing users’ Quality of Experience (QoE) in areas such as entertainment, healthcare, education, culture, and marketing. To support the researchers’ investigation, there have been developed many standalone software solutions and incipient architectural proposals to bind these applications to sensory effects devices, such as wind fans, scent emitters, vibration chairs, etc. These devices, in turn, are constantly evolving, making it difficult to update applications to be compatible with them. There is little or no interoperability between software and hardware in this realm, hindering reuse in other contexts. Every time a mulsemedia application is needed, new software is built mostly from scratch. This model has proven to be demanding, time-consuming, and costly mainly because it requires researchers and developers alike to gain knowledge about new devices, connectivity, communication protocols, and other particulars. The fact is that building such systems imposes a number of challenges and requirements (which are discussed in this thesis) due mainly to their ever-evolving and heterogeneous traits. As a result, few mulsemedia systems have remained reusable to be applied to different research purposes as opposed to the use of open mulsemedia datasets. Therefore, the main contribution of this thesis is a decoupled conceptual architecture to deal with variability of scenarios in mulsemedia delivery systems, which includes recommendations to cope with the variation of end-user applications and sensory effect devices through the support and reuse of even unforeseen communication and connectivity protocols, and sensory effects metadata (SEM). To evaluate it, an open-source and robust mulsemedia framework was developed. Then, a performance assessment was carried out on communication protocols for the integration between event-based applications, whereby temporal restrictions play a role, and the framework. Results indicated statistically significant differences in response time providing directions for optimized integrations. Finally, a user QoE subjective evaluation comparing a monolithic mulsemedia system with this framework was undertaken with results suggesting no evinced statistically significant differences in user perceived QoE between the systems under different aspects. Therefore, it is hoped that this work fosters the area of mulsemedia and HCI (Human-Computer Interaction) in the sense that researchers can leverage either the conceptual architecture to design mulsemedia delivery systems or the framework to carry out their experiments
A formal analysis of Identity and Sortality in the Unified Foundational Ontology (UFO)
(Universidade Federal do Espírito Santo, 2021-04-20) Nicola, João Rafael Moraes; Guizzardi, Giancarlo; https://orcid.org/0000-0002-3452-553X; http://lattes.cnpq.br/5297252436860003; https://orcid.org/0000-0001-8731-291X; http://lattes.cnpq.br/7572689551845981; Almeida, João Paulo Andrade; https://orcid.org/0000-0002-9819-3781; http://lattes.cnpq.br/4332944687727598
The Unified Foundational Ontology (UFO) is a conceptual framework grounded on principles derived from Ontology discipline of Philosophy, with applications in the field of Software Engineering, specially in Conceptual Modeling, as the semantic reference for the OntoUML modeling language. Among the concepts described in the UFO fragment of endurants (UFO-A), the concept of sortality plays a central role in the classification of UFO substantial universals. However, this concept, and the related concepts of identity and individuality currently lack a systematic formal characterization, hindering their application in the analysis of substantial universals. This research enriches the Unified Foundational Ontology (UFO) literature with a formal specification for a fragment of UFO-A that allows the characterization of these concepts. This specification is presented in Isabelle/HOL, a logical formalism that allows a machine-assisted verification. We construct a formal framework, based on this specification and on categoric-theoretic concepts through which we propose formal definitions for the concepts of individuality and identity, and, from these definitions, we propose a formal characterization of the concept of sortality. Illustrations and the application of the proposed definitions on the domain of conceptual modeling are also presented.
A 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 de
The 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.
A 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 dos
Crowdsourcing 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.
A 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 da
This 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.
A 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 Gonçalves
The 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.
A 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 Santos
In 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).
A 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 Nogueira
This 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
A 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 Fernando
In 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.
A 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 Loureiro
Clustering 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.
A Place-as-you-go In-network Framework by Modular Decomposition for Flexible Embedding to Software/Hardware Co-design
(Universidade Federal do Espírito Santo, 2022-10-21) Mafioletti, Diego Rossi; Martinello, Magnos; https://orcid.org/0000-0002-8111-1719; http://lattes.cnpq.br/7471111924336519; https://orcid.org/0000-0002-1513-9414; http://lattes.cnpq.br/2470233635439757; Mota, Vinicius Fernandes Soares; https://orcid.org/0000-0002-8341-8183; http://lattes.cnpq.br/9305955394665920; Both, Cristiano Bonato; https://orcid.org/0000-0002-9776-4888; http://lattes.cnpq.br/2658002010026792; Verdi, Fabio Luciano; https://orcid.org/0000-0002-5455-8910; http://lattes.cnpq.br/9143186843657940; Giaccone, Paolo
Cloud computing has become very popular as a computation platform, being part of people’s daily life. In order to deliver the cloud-required super-computing power, the network must play a crucial role by connecting hundreds of thousands of machines within data centres. However, with the rise of a new massive set of cloud-native and intensive applications (e.g. 5G, cloud robotics, deep learning, etc) combined with network function virtualisation (NFV), a significant strain has been placed on the processing capacity of server CPUs, demanding even higher performance and turning the network into a bottleneck. Typically, the network interface card (NIC) has been used to connect servers to the network. Although, smart network interface cards (SmartNICs) are becoming an increasingly popular method of offloading intensive packet processing tasks from servers, thus freeing CPU cycles to drive application performance. The critical challenge towards using a SmartNIC is how to make efficient use of these in-network heterogeneous computing resources, as there is a significant gap between application software and the computing capabilities of programmable devices. First, this device lacks generic programming models or abstractions, being usually programmed using low-level primitives or proprietary APIs. Second, the network developer needs to deal with the internal complexity of hardware resources, as well as manage the balance on offloading workloads, trying to find out the tradeoff between additional overheads and offloading benefits. It is needed to figure out how to co-design application logic between programmable network hardware and end-host servers within the edge computing paradigm. This thesis presents a novel framework for prototyping and deploying in-network applications. The framework is structured into a set of components that rely on i) application functional decomposition; ii) identification of logic blocks; iii) aggregation of overlapped functions merged and mapped on network functionalities in P4 language; iv) intercepting, interacting and forwarding with data structures for balancing the offloading of network flows. In order to demonstrate the principle of co-designing on diverse applications, Virtual Network Functions (VNFs) are created, and some of their functionally decomposed elements are deployed as small embedded Network Functions (eNFs) on in-network processors in sorted use cases, reviewing the framework components raised previously: decomposing network functions (i, ii, iii) and unifying components to fit into a set of VNFs/eNFs, examining latency, throughput and vCPU usage against their software implementation counterpart; intercepting and interacting with cloud robotics (iv), raising security concerns when using programmable data planes; evolving to security network functions running at in-network computing (i, ii, iii, iv), checking the overhead added by them; and modifying a PON upstream scheduler mechanism (iv), providing low latency requirements for applications.
A planning pipeline for software systems of autonomous vehicles
(Universidade Federal do Espírito Santo, 2023-09-04) Azevedo, Pedro Henrique Vieira de Oliveira; Gonçalves, Claudine Santos Baduê; https://orcid.org/0000-0003-1810-8581; http://lattes.cnpq.br/1359531672303446; http://lattes.cnpq.br/5958251435708396; Komati, Karin Satie; https://orcid.org/0000-0001-5677-4724; http://lattes.cnpq.br/9860697624155451; Santos, Thiago Oliveira dos; https://orcid.org/0000-0001-7607-635X; http://lattes.cnpq.br/5117339495064254; Boeres, Maria Claudia Silva; https://orcid.org/0000-0001-9801-2410; http://lattes.cnpq.br/0528154281423964; Wolf, Denis Fernando
The use of autonomous vehicles on public roads and in industrial environments has been growing in recent years and to achieve the higher level of autonomy, where no human intervention is needed, the vehicle must know the roads of the environment where it will operate, which allows it to travel from an initial location to a desired destination dealing with the uncertainties of the environments, such as static obstacles. In this work, we propose a planning pipeline for autonomous vehicle software systems. The pipeline is composed of an offline process and an online process. The offline process consists of two modules: (i) the Waypoints Editor, used to edit or even create entire new paths using an open-source vector graphics editor. (ii) The Multi-Level Road Network Generator constructs a representation of the environment in two levels of representation where the first one is used to guide the vehicle in the autonomous mission and the second one represents the paths and is used is route computation. The online process consists of three modules: (i) the Route Planner module to compute routes, (ii) the Off-Road Planner module to compute short paths in order to bring the car to the start of the route or to take the car from the end of the route to the final goal, and (iii) the Frenét Frames Path Planner to generate alternative paths to the right and left of the route and, in the presence of static obstacles, overtake them. We evaluated the performance of the proposed planning pipeline through simulations in three different real-world datasets using our Autonomous Vehicle Simulator module. Simulated experimental results showed that the proposed planning pipeline allowed the autonomous vehicle to know the environment as much as the user of the system wants and successfully execute missions from an initial position to a desired destination computing faster routes using the second level of the Multi-Level Road Network, dealing with static obstacles in the environment obeying the overtake safe distance restrictions imposed by the autonomous vehicle system.
A reactive GRASP algorithm for the multi-depot vehicle routing problem with time windows
(Universidade Federal do Espírito Santo, 2022-07-19) Souza, Israel Pereira de; Boeres, Maria Claudia Silva; https://orcid.org/0000-0001-9801-2410; http://lattes.cnpq.br/0528154281423964; Ochi, Luiz Satoru; Amaral, Andre Renato Sales; http://lattes.cnpq.br/4695002674556067
The vehicle routing problem (VRP) is a well know hard to solve problem in literature. In this work, we describe a reactive greedy randomized adaptive search procedures algorithm, for short, reactive GRASP, using a variable neighborhood descent (VND) algorithm as local search procedure to solve the multi-depot vehicle routing problem (MDVRP) and multi depot vehicle routing problem with time windows (MDVRPTW). This algorithm, called RGRASP+VND, combines four distinct local search procedures and a clustering technique. The Cordeau et al. dataset, a widely well known MDVRP benchmark, is considered for the experimental tests. RGRASP+VND achieves better results on most small instances and a lower average solution cost for all instances on the experimental tests when compared to the earlier GRASP approaches in the MDVRP literature. RGRASP+VND results are also compared with the state-of-the-art of MDVRP and MDVRPTW.
AAP - Um Ambiente para Aprendizagem de Programação
(Universidade Federal do Espírito Santo, 2014-12-04) Chagas, Lucinéia Barbosa da Costa; Menezes, Crediné Silva de; Tavares, Orivaldo de Lira; Nevado, Rosane Aragón de; Oliveira, Marcia Gonçalves de
Several research groups around the world have studied the process of learning how to program a computer. The learning of programming continues to be a complex problem because of the multiple skills and multiple stages required to the programming process. In the view of many students, introductory programming courses are considered difficult, this results in poor performance and many failures. In this research, we are interested in the creation of a supportive environment for learning programming in its several stages. Thus we define a virtual environment with computing resources to support the implementation of pedagogical architectures useful for learning programming. We present the elements of these architectures (objectives, strategies and digital resources) and their validations based on the apprentices’ experiences.
Abordagem do problema de programação de grade horária sujeito a restrições utilizando coloração de grafos
(Universidade Federal do Espírito Santo, 2007-11-12) Bello, Geraldo Simonetti; Rangel, Maria Cristina; Boeres, Maria Cláudia Silva; Oliveira, Elias Silva de; Ochi, Luiz Satoru
This work addresses the Class/Teacher Timetabling Problem and Graph Coloring Problem, presents features, describes the main approaches proposed in the literature for the solution of these two problems, including the reformulation of the basic version of the Class/Teacher Timetabling Problem as a Graph Coloring Problem, and uses the algorithms on this approach for their resolution. A Class/Teacher Timetabling Problem with additional constraints to those found in the basic version is chosen in the literature and a model that extends the correspondence between the two problems is developed, also contemplating additional constraints. Adaptations in a Tabu Search algorithm for Graph Coloring described in the literature and in the existing implementation in C language are proposed, in order to allow the resolution of the problem with the additional constraints considered. The chosen problem is reformulated as a Graph Coloring Problem and the modified algorithm is used for its resolution. The computational results for a set of instances related to the problem are presented and the effect of this reformulation in the results is verified, comparing them with those in the literature, which does not use this reformulation.
ADALiN – ambiente digital de aprendizagem de línguas
(Universidade Federal do Espírito Santo, 2019-02-19) Araujo, Raissa Arruda de; Tavares, Orivaldo de Lira; https://orcid.org/0000-0003-4734-3193; http://lattes.cnpq.br/5998785809434157; https://orcid.org/0000-0002-9085-7475; http://lattes.cnpq.br/4564768528153271; Menezes, Credine Silva de; https://orcid.org/0000-0002-2709-7135; http://lattes.cnpq.br/5454484334693909; Castro Junior, Alberto Nogueira de ; https://orcid.org/0000-0002-1752-8667; http://lattes.cnpq.br/5919189481858271
This dissertation presents the design, development, implementation and evaluation of a "digital environment" for learning natural languages, entitled ADALin. The novelty is that this environment is designed to serve a community of learners, without separating borders, in the sense that they reach different levels of proficiency, using five (5) abilities: reading, writing, speaking, listening, translating. This digital environment allows the use of Digital Learning Structures, created by teachers to be used for individual or collaborative learning with apprentices of different proficiency levels. Each learner's learning path is freely defined by himself. When the learner needs help choosing the next task to be developed, the environment recommends the activities, structured in the respective EDA, that are appropriate to the current level and proficiency of that learner.
Agregação de classificadores neurais via integral de Choquet com respeito a uma medida fuzzy
(Universidade Federal do Espírito Santo, 2016-07-15) Pacheco, André Georghton Cardoso; Kröhling, Renato Antônio; Boeres, Maria Claudia Silva; Papa, João Paulo
Data classification appears in many real-world problems, e.g., recognition of image patterns, differentiation among species of plants, classifying between benign and malignant tumors, among others. Many of these problems present data patterns, which are difficult to be identified, thus requiring more advanced techniques to be solved. Over the last few years, various classification algorithms have been developed to address these problems, but there is no classifier able to be the best choice in all situations. So, the concept of ensemble systems arise, which more than one methodology is used together to solve a particular problem. As a simple and effective methodology, ensemble of classifiers have been applied in several classification problems, aiming to improve performance and increase reliability of the final result. However, in order to improve the classification accuracy, an affective aggregation of classifiers must be performed. In this work, we present two contributions: first, we describe three classifiers based on neural networks, a multilayer feedforward trained by Levenberg-Marquardt algorithm; an extreme learning machine (ELM); and a discriminative restricted Boltmann machine (DRBM). Furthermore, we use conventional classifier k-nearest neighbors (KNN). Next, we propose an aggregation methodology to ensemble of classifiers using Choquet integral with respect to a fuzzy measure obtained by principal component analysis (PCA). Then, we apply this methodology to aggregate the classifiers performed to conventional benchmarks, for large database and the results are promising.
Algoritmo A-Estrela de estado híbrido aplicado à navegação autônoma de veículos
(Universidade Federal do Espírito Santo, 2013-08-28) Gonçalves, Michael André; Santos, Thiago Oliveira dos; Souza, Alberto Ferreira de; Gonçalves, Claudine Santos Badue; Aguiar, Edilson de; Chaimowicz, Luiz
In this work, we investigated the use of A-star algorithms (A*) with hybrid state in au-tonomous navigation of vehicles in a three-dimensional space. We have modeled the vehicle position (origin), the goal and other points of interest in the world (states) as nodes of a graph. The cost of navigating between these nodes were modeled as edges of the graph, and a variant of the A* algorithm was used to choose the best path be-tween origin and goal. In order to be able to avoid obstacles and achieve fast algorithm, we used a combination of two heuristics to estimate the cost of the current node to the goal node: one considering only the obstacles and without the limitation of rotation of the vehicle, and its dual disregarding the obstacles and with limited cinematic R³. We implemented the proposed navigation solution and incorporated it to the framework of robotics CARMEN as a navigation module for autonomous vehicles. Our module interacts with other existing modules (interface modules with sensors, mapping, local-ization, etc.) by means of message exchanging. It enables practical use of the algo-rithm. Results of experiments performed on IARA (Intelligent Robotic Autonomous Automobile - autonomous drive car developed in UFES) showed the viability of using the algorithm in simple and structured environments, such as roads, as well as in un-structured and complex environments, such as parking lots and unpaved areas,
Algoritmo genético híbrido aplicado ao problema de agrupamento de dados
(Universidade Federal do Espírito Santo, 2009-08-31) Alckmin, Danuza Prado de Faria; Varejão, Flávio Miguel; Martins, Simone de Lima; Boeres, Maria Claudia Silva
Clustering is a task that divides a data set in subgroups aiming that elements associated to one exactly group are more similar between themselves than elements of other groups. Organizing data in groups make it possible to identify similarities and differences between them, to extract useful information and conclusions regarding the data features. Clustering may be considered an optimization problem because it is intended to find the best combination of partitions among all possible combinations. An approach that can be applied to solve the clustering problem is the use of metaheuristics, which are procedures capable of escaping from local optima, once the use of exact methods is computationally infeasible. However, the majority of the metaheurísticas applied to clustering problem is not scalable for real or commercial bases. They are more effective for smaller instances of the problem trated. The computational cost necessary to calculate the solutions becomes greater in larger instances of the problem. For this reason, hybrid procedures that explore the combination of metaheuristics represent a promising approach for solving the clustering problem. This work shows a proposal of a Hybrid Genetic Clustering Algorithm that associates the process of global search to a local search heuristic and also initializes the population by different grouping techniques. Such improvements aim to direct the search for solutions next to the global optimal one. An experimental evaluation with real and synthetic databases is performed aiming to verify if the proposed approach presents an improvement in relation to the other evaluated algorithms. The result of this analysis shows that the proposed algorithm presents a better performance in four among the six evaluated algorithms. In addition, an analysis of the execution time shows that the execution time of our proposal is feasible, even though it is considerably longer than the execution times of the fast convergence algorithms.

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