Search results for " Selection"

A comparison between two feature selection algorithms

2017

This article provides a comparison of two feature selection algorithms, Information Gain Thresholding and Koller and Sahami's algorithm in the context of text document classification on the Reuters Corpus Volume 1 dataset. The algorithms were evaluated by testing the performance of classifiers trained on the features they select from a given dataset. Results show that Koller and Sahami's algorithm consistently outperforms Information Gain Thresholding by capturing interactions between features and avoiding redundancy among features, although it achieves its gains through increased complexity and longer running time.

Model selection using limiting distributions of second-order blind source separation algorithms

2015

Signals, recorded over time, are often observed as mixtures of multiple source signals. To extract relevant information from such measurements one needs to determine the mixing coefficients. In case of weakly stationary time series with uncorrelated source signals, this separation can be achieved by jointly diagonalizing sample autocovariances at different lags, and several algorithms address this task. Often the mixing estimates contain close-to-zero entries and one wants to decide whether the corresponding source signals have a relevant impact on the observations or not. To address this question of model selection we consider the recently published second-order blind identification proced…

Generalizability and Simplicity as Criteria in Feature Selection: Application to Mood Classification in Music

2011

Classification of musical audio signals according to expressed mood or emotion has evident applications to content-based music retrieval in large databases. Wrapper selection is a dimension reduction method that has been proposed for improving classification performance. However, the technique is prone to lead to overfitting of the training data, which decreases the generalizability of the obtained results. We claim that previous attempts to apply wrapper selection in the field of music information retrieval (MIR) have led to disputable conclusions about the used methods due to inadequate analysis frameworks, indicative of overfitting, and biased results. This paper presents a framework bas…

Coupling high-resolution satellite imagery with ALS-based canopy height model and digital elevation model in object-based boreal forest habitat type …

2014

We developed a classification workflow for boreal forest habitat type mapping. In object-based image analysis framework, Fractal Net Evolution Approach segmentation was combined with random forest classification. High-resolution WorldView-2 imagery was coupled with ALS based canopy height model and digital terrain model. We calculated several features (e.g. spectral, textural and topographic) per image object from the used datasets. We tested different feature set alternatives; a classification accuracy of 78.0 % was obtained when all features were used. The highest classification accuracy (79.1 %) was obtained when the amount of features was reduced from the initial 328 to the 100 most imp…

Pedagogisen ajattelun kehittyminen aineenopettajakoulutuksessa : tutkimus suoravalituista historian opettajaopiskelijoista

2013

Fighting performance as a predictor of mating success in male black grouse

2010

As a consequence of certain conflicting evolutionary interests of males and females, the sexes have taken on different reproductive roles. In many species, where females invest more in the production of offspring, males compete for the opportunities to reproduce and females attempt to choose the highest quality males to sire their offspring. Males of different species signal their quality in a variety of ways, including physical cues such as color signals or exaggerated secondary sexual characters, behavioral signals and acquisition of a dominance status through aggression towards other males. In the lekking black grouse only a few males manage to copulate and active fighting is required fo…

Comparison of wormlion behavior under man-made and natural shelters: urban wormlions more strongly prefer shaded, fine-sand microhabitats, construct …

2019

Abstract Urban habitats differ from their natural surroundings in various aspects, such as a higher temperature and a distinct species composition. It is therefore not surprising that animal behavior too differs between these habitat types. We studied the foraging and habitat selection behavior of a pit-building predator, a wormlion, originating from either an urban or a more natural site. Wormlions occur in nature under structures that provide shelter from sunlight and rain, such as caves, and are also common in cities, occurring under artificial shelters. Wormlions construct pit-traps to hunt arthropods, and the pits constructed by urban wormlions were larger than those constructed by wor…

Ecology of Vastedda della valle del Belìce cheeses: A review and recent findings to stabilize the traditional production

2018

The increasing request for classic foods has led to a higher demand for cheeses enjoying a “recognition of quality” status. This phenomenon has also affected Sicilian dairy products, in particular protected designation of origin (PDO) “Vastedda della valle del Belìce” (VdB), a cheese traditionally available only during the summer season, but requested year round. The variations of the microbial populations of raw milk among the seasons influence the microbiological quality of the cheeses produced. This review article reports the historical importance of cheeses and the traditional equipment used for dairy productions in Sicily with a specific focus on VdB. The microbial ecology of this chee…

Frequency and Density-Dependent Selection on Life-History Strategies - A Field Experiment

2008

Negative frequency-dependence, which favors rare genotypes, promotes the maintenance of genetic variability and is of interest as a potential explanation for genetic differentiation. Density-dependent selection may also promote cyclic changes in frequencies of genotypes. Here we show evidence for both density-dependent and negative frequency-dependent selection on opposite life-history tactics (low or high reproductive effort, RE) in the bank vole (Myodes glareolus). Densitydependent selection was evident among the females with low RE, which were especially favored in low densities. Instead, both negative frequency-dependent and density-dependent selection were shown in females with high RE…

An aposematic colour‐polymorphic moth seen through the eyes of conspecifics and predators – Sensitivity and colour discrimination in a tiger moth

2018

Although predation is commonly thought to exert the strongest selective pressure on coloration in aposematic species, sexual selection may also influence coloration. Specifically, polymorphism in aposematic species cannot be explained by natural selection alone. Males of the aposematic wood tiger moth (Arctia plantaginis) are polymorphic for hindwing coloration throughout most of their range. In Scandinavia, they display either white or yellow hindwings. Female hindwing coloration varies continuously from bright orange to red. Redder females and yellow males suffer least from bird predation. White males often have higher mating success than yellow males. Therefore, we ask whether females ca…