{"title":"Estimating the Number of Clusters Based on Sequential Clustering Algorithms","authors":"E. M. Real","doi":"10.1109/BRACIS.2016.050","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.050","url":null,"abstract":"The main goal of clustering algorithms is to organize a given set of data patterns into groups (clusters) and their main strategy is to group patterns based on their similarity. However, some clustering algorithms also require as an input parameter, the number of clusters the induced clustering should have, or then, a threshold value used for limiting for the number of induced clusters. Both, the number of cluster as well a threshold value are often unknown, however it is well-known that results of clustering tasks can be very sensitive to them. This work presents a method for empirically estimating both values. The method is based on multiple runs of sequential clustering algorithms, by using increasing threshold values. Results from experiments conducted using several data domains from two repositories, the UCI and the Keel, as well as a few artificially created data, are presented and a comparative analysis is carried out, as evidence of the good estimates on both values given by the method.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131702824","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lucas P. Queiroz, Francisco Caio M. Rodrigues, J. Gomes, Felipe T. Brito, Iago C. Brito, Javam C. Machado
{"title":"Fault Detection in Hard Disk Drives Based on Mixture of Gaussians","authors":"Lucas P. Queiroz, Francisco Caio M. Rodrigues, J. Gomes, Felipe T. Brito, Iago C. Brito, Javam C. Machado","doi":"10.1109/BRACIS.2016.036","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.036","url":null,"abstract":"Being able to detect faults in Hard Disk Drives (HDD) can lead to significant benefits to computer manufacturers, users and storage system providers. As a consequence, several works have focused on the development of fault detection algorithms for HDDs. Recently, promising results were achieved by methods using SMART (Self-Monitoring Analysis and Reporting Technology) features and anomaly detection algorithms based on Mahalanobis distance. Nevertheless, the performance of such methods can be seriously degraded when the normality assumption of the data does not hold. As a way to overcome this issue, we propose a new method for fault detection in HDD based on a Gaussian Mixture Model (GMM). The proposed method is tested in a real world dataset and its performance is compared to three other HDD fault detection methods.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131307197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Efficient Minimal Learning Machines with Reject Option","authors":"A. C. D. Oliveira, J. Gomes, A. Neto, A. Souza","doi":"10.1109/BRACIS.2016.078","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.078","url":null,"abstract":"Reject option is a widely used technique to improve the reliability of classification algorithms. It consists on withholding the classification of an instance if the classification is not reliable enough. Variants of well known classification algorithms have been proposed on the past years with diverse applications. In this work, we propose two variants of the Nearest Neighbor Minimal Learning Machine (NN-MLM) with reject option. The NN-MLM is an computationally efficient version of the recently proposed supervised learning algorithm called Minimal Learning Machine (MLM). The two variants (rejoNN-MLM and rejoNNwMLM) are evaluated on real world datasets and compared to state-of-the-art classifiers with reject option. Result show that both methods are a valid alternative for problems that require a reject option.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125334046","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Iago Correa, Paulo L. J. Drews-Jr, M. S. Souza, V. Tavano
{"title":"Supervised Microalgae Classification in Imbalanced Dataset","authors":"Iago Correa, Paulo L. J. Drews-Jr, M. S. Souza, V. Tavano","doi":"10.1109/BRACIS.2016.020","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.020","url":null,"abstract":"Microalgae are unicellular organisms that have physical characteristics such as size, shape or even the present structures. Classifying them manually may require great effort from experts since thousands of microalgae can be found in a small sample of water. Furthermore, the manual classification is not a trivial operation. The results show an important improvement in the classification quality when cost matrix and sampling methods are associated with supervised algorithm.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128201973","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Towards Fixation Prediction: A Nonparametric Estimation-Based Approach through Key-Points","authors":"Saulo A. F. Oliveira, A. Neto, J. Gomes","doi":"10.1109/BRACIS.2016.077","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.077","url":null,"abstract":"When we look at our environment, we primarily pay attention to visually distinctive objects. Saliency maps are topographical maps of the visually salient parts of scenes in which such visually distinctive objects, henceforth called visually important or salient, can be easily highlighted. Computing these maps is still an open problem whose interest is growing in computer vision. Thus, in this work, we propose a new method to compute these maps based on salient points extracted through local descriptors. After, a nonparametric kernel density estimation method is employed to estimate the final saliency map. In order to assess the performance, we carry out experiments on two large benchmark databases to demonstrate the proposed method performance against the state-of-the-art methods using different scoring metrics. Due to the experimental results obtained, we consider the proposed method is a valid alternative for saliency detection.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"85 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114475030","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A Dynamic Gesture Recognition System to Translate between Sign Languages in Complex Backgrounds","authors":"D. Neiva, C. Zanchettin","doi":"10.1109/BRACIS.2016.082","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.082","url":null,"abstract":"Sign languages, used by people with hearing impairments to communicate, are not universal. Just like any other language, every country has its own, which makes it difficult to establish communication, as usually people only know their native sign language. This paper presents a novel integrated system to minimize this barrier by combining a web application that uses computer vision techniques and Extreme Learning Machines with a mobile application, to translate between sign languages.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115886568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Elliackin M. N. Figueiredo, Danilo R. B. Araújo, C. J. A. B. Filho, Teresa B Ludermir
{"title":"Physical Topology Design of Optical Networks Aided by Many-Objective Optimization Algorithms","authors":"Elliackin M. N. Figueiredo, Danilo R. B. Araújo, C. J. A. B. Filho, Teresa B Ludermir","doi":"10.1109/BRACIS.2016.080","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.080","url":null,"abstract":"In this paper, we investigate the performance of two many-objective evolutionary algorithms to design optical networks. Many-objective algorithms are a particular class of multi-objective algorithms whose goal is to solve problems with four or more conflicting objectives. We compared the state of the art algorithm, called NSGA-III, with a recently proposed swarmbased approach, named MaOPSO. We consider four important objectives to design optical networks: network blocking probability, capital expenditures, energy consumption and robustness. According to our results, the new many-objective based on the particle swarm optimisation algorithm outperformed the NSGAIII for this challenging problem and this study suggests that MaOPSO can be advantageous to tackle real world problems.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115057179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. P. Bueno, D. Mauá, L. N. Barros, Fabio Gagliardi Cozman
{"title":"Markov Decision Processes Specified by Probabilistic Logic Programming: Representation and Solution","authors":"T. P. Bueno, D. Mauá, L. N. Barros, Fabio Gagliardi Cozman","doi":"10.1109/BRACIS.2016.068","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.068","url":null,"abstract":"Probabilistic logic programming combines logic and probability, so as to obtain a rich modeling language. In this work, we extend ProbLog, a popular probabilistic logic programming language, with new constructs that allow the representation of (infinite-horizon) Markov decision processes. This new language can represent relational statements, including symmetric and transitive definitions, an advantage over other planning domain languages such as RDDL. We show how to exploit the logic structure in the language to perform Value Iteration. Preliminary experiments demonstrate the effectiveness of our framework.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115737793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Romero F. A. B. de Morais, P. Miranda, Ricardo Martins
{"title":"A Meta-Learning Method to Select Under-Sampling Algorithms for Imbalanced Data Sets","authors":"Romero F. A. B. de Morais, P. Miranda, Ricardo Martins","doi":"10.1109/BRACIS.2016.076","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.076","url":null,"abstract":"Imbalanced data sets originating from real world problems, such as medical diagnosis, can be found pervasive. Learning from imbalanced data sets poses its own challenges, as common classifiers assume a balanced distribution of examples' classes in the data. Sampling techniques overcome the imbalance in the data by modifying the examples' classes distribution. Unfortunately, selecting a sampling technique together with its parameters is still an open problem. Current solutions include the brute-force approach (try as many techniques as possible), and the random search approach (choose the most appropriate from a random subset of techniques). In this work, we propose a new method to select sampling techniques for imbalanced data sets. It uses Meta-Learning and works by recommending a technique for an imbalanced data set based on solutions to previous problems. Our experimentation compared the proposed method against the brute-force approach, all techniques with their default parameters, and the random search approach. The results of our experimentation show that the proposed method is comparable to the brute-force approach, outperforms the techniques with their default parameters most of the time, and always surpasses the random search approach.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122252505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Random Walk in Feature-Sample Networks for Semi-supervised Classification","authors":"F. Verri, Liang Zhao","doi":"10.1109/BRACIS.2016.051","DOIUrl":"https://doi.org/10.1109/BRACIS.2016.051","url":null,"abstract":"Positive-unlabeled learning is a semi-supervised task in which only some positive-labeled and many unlabeled samples are available. The goal of its transductive setting is to label all unlabeled data at once. In this paper, we developed a technique to grade positive-class pertinence levels of each sample, and we interpret the grades to classify the unlabeled ones. In our method, a sparse binary matrix represents the input data, which determines the feature–sample network whose vertices represent samples and attributes. The limiting probabilities of a random walk in the network estimate the pertinence levels. The results are evaluated regarding both class discrimination and classification accuracy. Computer simulations reveal that our model performs well in positive-unlabeled learning, especially with few labeled samples. Notably, the outcomes compare to the results from supervised methods, which profit from most data labeled. Additionally, the technique has linear time and space complexity if the input dataset is already in a sparse representation. The low computational cost of the construction and update of the feature–sample network allows for extensions of the technique to several learning problems, including online learning and dimensionality reduction.","PeriodicalId":183149,"journal":{"name":"2016 5th Brazilian Conference on Intelligent Systems (BRACIS)","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2016-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128469176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}