Selection and educational labeling as sociological processes

Este artículo aborda aspectos teóricos y empíricos en la perspectiva de la sociología de la educación, mirando el fenómeno de la selección educacional que ocurre durante la carrera escolar. En el marco de América Latina como región que todavía se mueve entre, por un lado, la defensa o la búsqueda de la identidad la búsqueda de la autonomía y la independencia y, por otro, la inclusión –para algunos irreversible-en la globalización y la apertura hacia los lineamientos de las organizaciones internacionales, este trabajo quiere responder a las siguientes cuestiones: ¿Por qué solamente unos pocos tienen oportunidad de estudiar en la Universidad? ¿Cuáles son los aspectos determinantes para tener éxito o fracasar en el sistema escolar de la educación superior? ¿Cuáles son las condiciones por las que algunos deciden aspirar o no a la Universidad? Finalmente, las conclusiones se enfocan a la importancia de la actitud de los estudiantes para ir a la Universidad, el papel del maestro en el éxito o fracaso de los estudiantes y la mediación del contexto social para superar los obstáculos de su entrada y permanencia en la educación superior.This paper explores theoretical approaches and empirical works in the perspective of the sociology of education, looking for insights into the phenomenon of educational selection that occurs during the school career. Within the frame of Latin America as a región that still tenses between the defense and/or search for identity, the fight for autonomy and independence in one part and for the other the inclusion -for many irreversible- into the globalization and the openness to the guidelines of international organizations, the structure of the work is developed to answer the following questions: why only some have opportunity to study at the university? Which are the determinants of success or failure in the school system of higher education? What are the conditions for some to decide aspire or not to university? Finally, conclusions focuses on the importance of the attitude of students to go to college, the teacher’s role in the success or failure of students and mediation of social background on achievement to overcome the obstacles of their entrance and permanence in higher education

Improving the Evolutionary Coding for Machine Learning Tasks

The most influential factors in the quality of the solutions found by an evolutionary algorithm are a correct coding of the search space and an appropriate evaluation function of the potential solutions. The coding of the search space for the obtaining of decision rules is approached, i.e., the representation of the individuals of the genetic population. Two new methods for encoding discrete and continuous attributes are presented. Our “natural coding” uses one gene per attribute (continuous or discrete) leading to a reduction in the search space. Genetic operators for this approached natural coding are formally described and the reduction of the size of the search space is analysed for several databases from the UCI machine learning repository.Comisión Interministerial de Ciencia y Tecnología TIC1143–C03–0

Fast Feature Ranking Algorithm

The attribute selection techniques for supervised learning, used in the preprocessing phase to emphasize the most relevant attributes, allow making models of classification simpler and easy to understand. The algorithm has some interesting characteristics: lower computational cost (O(m n log n) m attributes and n examples in the data set) with respect to other typical algorithms due to the absence of distance and statistical calculations; its applicability to any labelled data set, that is to say, it can contain continuous and discrete variables, with no need for transformation. In order to test the relevance of the new feature selection algorithm, we compare the results induced by several classifiers before and after applying the feature selection algorithms

Fast Feature Selection by Means of Projections

The attribute selection techniques for supervised learning, used in the preprocessing phase to emphasize the most relevant attributes, allow making models of classification simpler and easy to understand. The algorithm (SOAP: Selection of Attributes by Projection) has some interesting characteristics: lower computational cost (O(m n log n) m attributes and n examples in the data set) with respect to other typical algorithms due to the absence of distance and statistical calculations; its applicability to any labelled data set, that is to say, it can contain continuous and discrete variables, with no need for transformation. The performance of SOAP is analyzed in two ways: percentage of reduction and classification. SOAP has been compared to CFS [4] and ReliefF [6]. The results are generated by C4.5 before and after the application of the algorithms

Gene Ranking from Microarray Data for Cancer Classification : A Machine Learning Approach

Traditional gene selection methods often select the top–ranked genes according to their individual discriminative power. We propose to apply feature evaluation measure broadly used in the machine learning field and not so popular in the DNA microarray field. Besides, the application of sequential gene subset selection approaches is included. In our study, we propose some well-known criteria (filters and wrappers) to rank attributes, and a greedy search procedure combined with three subset evaluation measures. Two completely different machine learning classifiers are applied to perform the class prediction. The comparison is performed on two well–known DNA microarray data sets. We notice that most of the top-ranked genes appear in the list of relevant–informative genes detected by previous studies over these data sets.Comisión Interministerial de Ciencia y Tecnología (CICYT) TIN2004–00159Comisión Interministerial de Ciencia y Tecnología (CICYT) TIN2004-06689C030

Searching for rules to detect defective modules: A subgroup discovery approach

Data mining methods in software engineering are becoming increasingly important as they can support several aspects of the software development life-cycle such as quality. In this work, we present a data mining approach to induce rules extracted from static software metrics characterising fault-prone modules. Due to the special characteristics of the defect prediction data (imbalanced, inconsistency, redundancy) not all classification algorithms are capable of dealing with this task conveniently. To deal with these problems, Subgroup Discovery (SD) algorithms can be used to find groups of statistically different data given a property of interest. We propose EDER-SD (Evolutionary Decision Rules for Subgroup Discovery), a SD algorithm based on evolutionary computation that induces rules describing only fault-prone modules. The rules are a well-known model representation that can be easily understood and applied by project managers and quality engineers. Thus, rules can help them to develop software systems that can be justifiably trusted. Contrary to other approaches in SD, our algorithm has the advantage of working with continuous variables as the conditions of the rules are defined using intervals. We describe the rules obtained by applying our algorithm to seven publicly available datasets from the PROMISE repository showing that they are capable of characterising subgroups of fault-prone modules. We also compare our results with three other well known SD algorithms and the EDER-SD algorithm performs well in most cases.Ministerio de Educación y Ciencia TIN2007-68084-C02-00Ministerio de Educación y Ciencia TIN2010-21715-C02-0

Biclustering on expression data: A review

Biclustering has become a popular technique for the study of gene expression data, especially for discovering functionally related gene sets under different subsets of experimental conditions. Most of biclustering approaches use a measure or cost function that determines the quality of biclusters. In such cases, the development of both a suitable heuristics and a good measure for guiding the search are essential for discovering interesting biclusters in an expression matrix. Nevertheless, not all existing biclustering approaches base their search on evaluation measures for biclusters. There exists a diverse set of biclustering tools that follow different strategies and algorithmic concepts which guide the search towards meaningful results. In this paper we present a extensive survey of biclustering approaches, classifying them into two categories according to whether or not use evaluation metrics within the search method: biclustering algorithms based on evaluation measures and non metric-based biclustering algorithms. In both cases, they have been classified according to the type of meta-heuristics which they are based on.Ministerio de Economía y Competitividad TIN2011-2895

Evolutionary Biclustering based on Expression Patterns

The majority of the biclustering approaches for microarray data analysis use the Mean Squared Residue (MSR) as the main evaluation measure for guiding the heuristic. MSR has been proven to be inefficient to recognize several kind of interesting patterns for biclusters. Transposed Virtual Error (VEt ) has recently been discovered to overcome MSR drawbacks, being able to recognize shifting and/or scaling patterns. In this work we propose a parallel evolutionary biclustering algorithm which uses VEt as the main part of the fitness function, which has been designed using the volume and overlapping as other objectives to optimize. The resulting algorithm has been tested on both synthetic and benchmark real data producing satisfactory results. These results has been compared to those of the most popular biclustering algorithm developed by Cheng and Church and based in the use of MSR.Ministerio de Ciencia y Tecnología TIN2007-68084-C02-0

Measuring the Quality of Shifting and Scaling Patterns in Biclusters

The most widespread biclustering algorithms use the Mean Squared Residue (MSR) as measure for assessing the quality of biclusters. MSR can identify correctly shifting patterns, but fails at discovering biclusters presenting scaling patterns. Virtual Error (VE) is a measure which improves the performance of MSR in this sense, since it is effective at recognizing biclusters containing shifting patters or scaling patterns as quality biclusters. However, VE presents some drawbacks when the biclusters present both kind of patterns simultaneously. In this paper, we propose a improvement of VE that can be integrated in any heuristic to discover biclusters with shifting and scaling patterns simultaneously.Ministerio de Ciencia y Tecnología TIN2007-68084-C02-0