Search results for "election"

Ensemble Feature Selection Based on the Contextual Merit

2001

Recent research has proved the benefits of using ensembles of classifiers for classification problems. Ensembles constructed by machine learning methods manipulating the training set are used to create diverse sets of accurate classifiers. Different feature selection techniques based on applying different heuristics for generating base classifiers can be adjusted to specific domain characteristics. In this paper we consider and experiment with the contextual feature merit measure as a feature selection heuristic. We use the diversity of an ensemble as evaluation function in our new algorithm with a refinement cycle. We have evaluated our algorithm on seven data sets from UCI. The experiment…

2004

This paper presents the use of Support Vector Machines (SVMs) for prediction and analysis of antisense oligonucleotide (AO) efficacy. The collected database comprises 315 AO molecules including 68 features each, inducing a problem well-suited to SVMs. The task of feature selection is crucial given the presence of noisy or redundant features, and the well-known problem of the curse of dimensionality. We propose a two-stage strategy to develop an optimal model: (1) feature selection using correlation analysis, mutual information, and SVM-based recursive feature elimination (SVM-RFE), and (2) AO prediction using standard and profiled SVM formulations. A profiled SVM gives different weights to …

Ensemble Feature Selection Based on Contextual Merit and Correlation Heuristics

2001

Recent research has proven the benefits of using ensembles of classifiers for classification problems. Ensembles of diverse and accurate base classifiers are constructed by machine learning methods manipulating the training sets. One way to manipulate the training set is to use feature selection heuristics generating the base classifiers. In this paper we examine two of them: correlation-based and contextual merit -based heuristics. Both rely on quite similar assumptions concerning heterogeneous classification problems. Experiments are considered on several data sets from UCI Repository. We construct fixed number of base classifiers over selected feature subsets and refine the ensemble iter…

A generalized transitive closure for relational queries

1988

We augment relational algebra with a generalized transitive closure operator that allows for the efficient evaluation of a subclass of recursive queries. The operator is based on a composition operator which is as general as possible when the operator is required to be associative and when only relational algebra operators are used in its definition. The closure of such a composition can be computed using the well-known efficient algorithms designed for the computation of the usual transitive closure. Besides the case in which complete materialization of recursive relations are required, our strategy also yields an efficient solution in the case in which a selection is applied to the closur…

Signals of major histocompatibility complex overdominance in a wild salmonid population

2009

The major histocompatibility complex (MHC) contains the most variable genes in vertebrates, but despite extensive research, the mechanisms maintaining this polymorphism are still unresolved. One hypothesis is that MHC polymorphism is a result of balancing selection operating by overdominance, but convincing evidence for overdominant selection in natural populations has been lacking. We present strong evidence consistent with MHC-specific overdominance in a free-living population of Arctic charr (Salvelinus alpinus) in northernmost Europe. In this population, where just two MHC alleles were observed, MHC heterozygous fish had a lower parasite load, were in better condition (as estimated by a…

A Spanish 'Yes, we can!' against the two-party system: the development of political party Podemos

2017

This article develops an analysis of the internal functioning of the Spanish party Podemos and its structural make-up. The used methodology consists of: 1) a descriptive analysis of the development of Podemos, based on the available information in the media; 2) an analysis centered on the presence of Podemos in social networks and the mainstream media, in addition to electoral results and polls. The analysis attempts to determine the following: the party’s decision-making process, along with the type of relationships established between leaders and supporters; to what extent the Internet is used as a primary tool for organization, mobilization and political propaganda; and the extent of the…

Patterns of variation in tail ornament size in birds

1988

In recent years several different kinds of sexual selection models have been developed, and tail ornaments in birds have frequently been used as an example of a sexually selected character where the models might apply. However, very little is known about intra- and interpopulation variation in ornament size. We have studied the elongated tail ornaments in four species of whydahs Vidua, the forktailed flycatcher Tyrannus savana and the Asian paradise flycatcher Terpsiphone paradisi. Ornaments were relatively longer in males with the longest tarsi (‘heterogony’ with positive allometry). Also, tail lengths were remarkably variable within each geographical area, the coefficient of variation (av…

Corynosoma cetaceum in the stomach of Franciscanas, pontoporia blainvillei (Cetacea): an exceptional case of habitat selection by an Acanthocephalan

2001

Adult acanthocephalans are typically found in the intestine of vertebrates, where they can readily absorb nutrients. However, Corynosoma cetaceum has been frequently reported in the stomach of cetaceans from the Southern Hemisphere. The ecological significance of this habitat was investigated by examining data on number, sex ratio, maturity status, biomass, and fecundity of C. cetaceum in different parts of the digestive tract of 44 franciscanas Pontoporia blainvillei. Individual C. cetaceum occurred in the pyloric stomach (PS) and, to lesser degrees, in the duodenal ampulla (DA) and the main stomach (MS). Females outnumbered males in all chambers, although the sex ratio was closer to 1:1 i…

Remarks on the environmental adaptation of man.

1971

In this paper the geographical variability of some morphological, physiological and serological traits of man is discussed with respect to the question, how far this variability can be considered as the result of selective adaptation processes. Though there is already some evidence supporting such an assumption, much more detailed and exactly planned research is necessary to clear the indubitable relations between the distribution patterns of anthropological traits and the various environmental conditions of human biotops. Particularly much more work is required to understand the causative mechanisms on which these relations are based.

Marketing Research Regarding the Usage of Online Social Networking Sites by High School Students

2013

This paper aims to present the concept of online social networks (OSN) and its evolution in the world of business as well as several important advantages and disadvantages of using online social networking sites. We are presenting a quantitative research on the main reasons for using online networking sites by high schools students from the several counties of Romania. The authors will present the results of the research which underline: the main activities undertaken by students with this new communication tool, the average number of friends the students have and the selection criteria for them as well as the influence level of OSN sites on the life and activity (school and private) of the…