A carregar...
26 resultados
Resultados da pesquisa
A mostrar 1 - 10 de 26
- An automatic generation of textual pattern rules for digital content filters proposal, using grammatical evolution genetic programmingPublication . Basto-Fernandes, Vitor; Yevseyeva, Iryna; Frantz, Rafael Z.; Grilo, Carlos Fernando Almeida; Díaz, Noemí Pérez; Emmerich, Michael
- Characterising Enterprise Application Integration Solutions as Discrete-Event SystemsPublication . Sawicki, Sandro; Frantz, Rafael Z.; Basto-Fernandes, Vitor; Fabricia Roos-Frantz, Fabricia; Yevseyeva, Iryna; Corchuelo, RafaelIt is not difficult to find an enterprise which has a software ecosystem composed of applications that were built using different technologies, data models, operating systems, and most often were not designed to exchange data and share functionalities. Enterprise Application Integration provides methodologies and tools to design and implement integration solutions. The state-of-the-art integration technologies provide a domain-specific language that enables the design of conceptual models for integration solutions. The analysis of integration solutions to predict their behaviour and find possible performance bottlenecks is an important activity that contributes to increase the quality of the delivered solutions, however, software engineers follow a costly, risky, and time-consuming approach. Integration solutions shall be understood as a discrete-event system. This chapter introduces a new approach based on simulation to take advantage of well-established techniques and tools for discrete-event simulation, cutting down cost, risk, and time to deliver better integration solutions.
- A spam filtering multi-objective optimization study covering parsimony maximization and three-way classificationPublication . Basto-Fernandes, Vitor; Yevseyeva, Iryna; Méndez, José R.; Zhao, Jiaqi; Fdez-Riverola, Florentino; Emmerich, Michael T.M.Classifier performance optimization in machine learning can be stated as a multi-objective optimization problem. In this context, recent works have shown the utility of simple evolutionary multi-objective algorithms (NSGA-II, SPEA2) to conveniently optimize the global performance of different anti-spam filters. The present work extends existing contributions in the spam filtering domain by using three novel indicator-based (SMS-EMOA, CH-EMOA) and decomposition-based (MOEA/D) evolutionary multiobjective algorithms. The proposed approaches are used to optimize the performance of a heterogeneous ensemble of classifiers into two different but complementary scenarios: parsimony maximization and e-mail classification under low confidence level. Experimental results using a publicly available standard corpus allowed us to identify interesting conclusions regarding both the utility of rule-based classification filters and the appropriateness of a three-way classification system in the spam filtering domain.
- Multiobjective optimization of classifiers by means of 3D convex-hull-based evolutionary algorithmsPublication . Zhao, Jiaqi; Basto-Fernandes, Vitor; Jiao, Licheng; Yevseyeva, Iryna; Maulana, Asep; Li, Rui; Bäck, Thomas; Tang, Ke; Emmerich, Michael T.M.The receiver operating characteristic (ROC) and detection error tradeoff (DET) curves are frequently used in the machine learning community to analyze the performance of binary classifiers. Recently, the convex-hull-based multiobjective genetic programming algorithm was proposed and successfully applied to maximize the convex hull area for binary classification problems by minimizing false positive rate and maximizing true positive rate at the same time using indicator-based evolutionary algorithms. The area under the ROC curve was used for the performance assessment and to guide the search. Here we extend this research and propose two major advancements: Firstly we formulate the algorithm in detection error tradeoff space, minimizing false positives and false negatives, with the advantage that misclassification cost tradeoff can be assessed directly. Secondly, we add complexity as an objective function, which gives rise to a 3D objective space (as opposed to a 2D previous ROC space). A domain specific performance indicator for 3D Pareto front approximations, the volume above DET surface, is introduced, and used to guide the indicator-based evolutionary algorithm to find optimal approximation sets. We assess the performance of the new algorithm on designed theoretical problems with different geometries of Pareto fronts and DET surfaces, and two application-oriented benchmarks: (1) Designing spam filters with low numbers of false rejects, false accepts, and low computational cost using rule ensembles, and (2) finding sparse neural networks for binary classification of test data from the UCI machine learning benchmark. The results show a high performance of the new algorithm as compared to conventional methods for multicriteria optimization.
- RuleSIM: a toolkit for simulating the operation and improving throughput of rule-based spam filtersPublication . Ruano-Ordás, David; Fdez-Glez, Jorge; Fdez-Riverola, Florentino; Basto-Fernandes, Vitor; Méndez, José RamónThis paper introduces RuleSIM, a toolkit comprising different simulation tools specifically designed to aid researchers concerned about spam-filtering throughput. RuleSIM allows easily designing, developing, simulating and comparing new scheduling heuristics using different filters and sets of e-mails. Simulation results can be both graphically analysed, by using different complementary views, and quantitatively compared through several measures. Moreover, the underlying RuleSIM API can be easily integrated with third-party Java optimization platforms to facilitate debugging and achieve better configurations for rule scheduling. RuleSIM is free software distributed under the terms of GNU Lesser General Public License, and both source code and documentation are publicly available at https://github.com/rulesim/v2.0. Copyright © 2015 John Wiley & Sons, Ltd.
- A survey of diversity-oriented optimizationPublication . Basto-Fernandes, Vitor; Yevseyeva, Iryna; Emmerich, Michael
- Information architecture for IS function : a case studyPublication . Carriço, Nelson; Varajão, João; Basto-Fernandes, Vitor; Dominguez, CarolineToday’s complex, unstable and competitive society raises several difficulties to organisations. In this context, Information and Communications Technologies (ICT) and information itself have become resources of vital importance. The pressing need for Information Systems (IS) to meet several business requirements, in addition to the complexity involved in technology and business management, turns the IS Function one of the main areas of influence for success of modern organisations. Through its capacity of representing activities, management objects and corresponding relations, the Information Architecture of the Information Systems Function (IAISF), a technique derived from the well-known Information Architecture but exclusively focused on the Information Systems Function (ISF), allows not only the conceptualization and understanding of the ISF itself, but also of its interactions with other areas within organizations. This paper presents the main results of a case study related to the application of the IAISF technique in a computer service centre of a University.
- Desafios para a implantação de soluções de integração de aplicações empresariais em provedores de computação em nuvemPublication . Frantz, Rafael; Sawicki, Sandro; Roos-Frantz, Fabricia; Corchuelo, Rafael; Basto-Fernandes, Vitor; Hernández, InmaNos últimos anos o campo de estudos conhecido como Integração de Aplicações Empresariais tem desempenhado um importante papel ao proporcionar metodologias, técnicas e ferramentas para que as empresas possam desenvolver soluções de integração, visando reutilizar suas aplicações e dar suporte às novas demandas que surgem com a evolução dos seus processos de negócio. A Computação em Nuvem é parte de uma nova realidade, na qual tanto pequenas como grandes empresas têm a sua disposição uma infraestrutura de TI de alta capacidade, a um baixo custo, na qual podem implantar e executar suas soluções de integração. O modelo de cobrança adotado pelos provedores de Computação em Nuvem se baseia na quantidade de recursos computacionais consumidos por uma solução de integração. Tais recursos podem ser conhecidos, basicamente, de duas formas distintas: a partir da execução real de uma solução de integração em um motor de orquestração, ou a partir da simulação do modelo conceitual que descreve a solução sem que a mesma tenha que ser previamente implementada. Ainda, é desejável que os provedores proporcionem modelos conceituais que descrevam detalhadamente a variabilidade de serviços e as restrições entre eles. A revisão da literatura técnica e científica evidencia que não existem metodologias, técnicas e ferramentas para estimar a demanda de recursos computacionais consumidos por soluções de integração, a partir de seus modelos conceituais. Além disso, os provedores de Computação em Nuvem não possuem ou disponibilizam os modelos conceituais dos serviços que possam ser contratados. Tais questões constituem a base para que se possa estabelecer um processo e desenvolver ferramentas de apoio a tomada de decisão para a implantação de soluções de integração de aplicações empresariais em provedores de Computação em Nuvem.
- Survey on Anti-spam Single and Multi-objective OptimizationPublication . Yevseyeva, Iryna; Basto-Fernandes, Vitor; Méndez, José R.In this paper anti-spam filtering is presented as a cumbersome service, as opposing to a software product perspective. The human effort for setting up, adaptation, maintenance and tuning of filters for spam detection is stressed. Because choosing the proper scores (relevance) for the spam filters is essential to the accuracy of the anti-spam system and one of the biggest challenges for the Apache SpamAssassin project (the most widely adopted anti-spam open-source software), we present a survey on single and multi-objective optimization studies for this purpose. Our survey constitutes a contribution and a stimulus for further research on this open research topic, with particular emphasis on evolutionary multi-objective approaches.
- Evolutionary Multi-objective Scheduling for Anti-Spam Filtering Throughput OptimizationPublication . Ruano-Ordás, David; Basto-Fernandes, Vitor; Yevseyeva, Iryna; Méndez, José RamónThis paper presents an evolutionary multi-objective optimization problem formulation for the anti-spam filtering problem, addressing both the classification quality criteria (False Positive and False Negative error rates) and email messages classification time (minimization). This approach is compared to single objective problem formulations found in the literature, and its advantages for decision support and flexible/adaptive anti-spam filtering configuration is demonstrated. A study is performed using the Wirebrush4SPAM framework anti-spam filtering and the SpamAssassin email dataset. The NSGA-II evolutionary multi-objective optimization algorithm was applied for the purpose of validating and demonstrating the adoption of this novel approach to the anti-spam filtering optimization problem, formulated from the multi-objective optimization perspective. The results obtained from the experiments demonstrated that this optimization strategy allows the decision maker (anti-spam filtering system administrator) to select among a set of optimal and flexible filter configuration alternatives with respect to classification quality and classification efficiency.
- «
- 1 (current)
- 2
- 3
- »