Search results for " selection"
showing 10 items of 1271 documents
Microhabitat selection and audible sexual signalling in the wolf spider Hygrolycosa rubrofasciata (Araneae, Lycosidae)
2000
We studied the microhabitat selection and male sexual signalling behaviour in the wolf spider Hygrolycosa rubrofasciata (Ohlert). Males strike dry leaves with their abdomen, producing an audible sexual drumming signal, and females use this signal to choose mating partners. In the field we followed male drum- ming rate and microhabitat selection using both the mark-recapture method and direct observations. In the laboratory we conducted an experiment on male micro- habitat and drumming substrate selection. We found that in the field males were not distributed randomly among the habitat; fewer males were found in areas that had high sedge cover, low elevation, and low dry leaf cover. In the l…
Sexual selection in the wolf spider Hygrolycosa rubrofasciata: female preference for drum duration and pulse rate
2002
The unusual form of sexual signaling, the drumming produced by the wolf spider Hygrolycosa rubrofasciata, allows exceptionally detailed studies of female preference patterns against signal characteristics. It is easy to manipulate the signals and to use large numbers of females in playback experiments. Males of H. rubrofasciata produce drums by striking their abdomen against dry leaves on the ground. Drums travel not only as substrate-borne vibrations, but also as airborne acoustic signals. Females respond sooner to drums transferred as substrate borne, but the mode of signal transfer has no effect on female preference for different types of drums. We investigated the effects of two key com…
Social Influence Maximization in Hypergraphs
2021
This work deals with a generalization of the minimum Target Set Selection (TSS) problem, a key algorithmic question in information diffusion research due to its potential commercial value. Firstly proposed by Kempe et al., the TSS problem is based on a linear threshold diffusion model defined on an input graph with node thresholds, quantifying the hardness to influence each node. The goal is to find the smaller set of items that can influence the whole network according to the diffusion model defined. This study generalizes the TSS problem on networks characterized by many-to-many relationships modeled via hypergraphs. Specifically, we introduce a linear threshold diffusion process on such …
Hyperspectral LCTF-based system for classification of decay in mandarins caused by Penicillium digitatum and Penicillium italicum using the most rele…
2013
[EN] Green mold (Penicillium digitatum) and blue mold (Penicillium italicum) are important sources of postharvest decay affecting the commercialization of mandarins. These fungi infections produce enormous economic losses in mandarin production if early detection is not carried out. Nowadays, this detection is performed manually in dark chambers, where the fruit is illuminated by ultraviolet light to produce fluorescence, which is potentially dangerous for humans. This paper documents a new methodology based on hyperspectral imaging and advanced machine-learning techniques (artificial neural networks and classification and regression trees) for the segmentation and classification of images …
La vocalidad del violín en el norte de Italia en torno a 1600
2021
Throughout the present research I intend to demonstrate the powerful link between the vocal practice in accompanied monody and the way Early Italian violin music ought to be interpreted. Due to the scarce amount of articulation and ornamentation in this music, I consider that historical criteria should be found in order to back up the subjective choices in its performance. According to this, I focus on reviewing sources that describe the vocal practice around 1600, but also contemporary sources in which we can find instructions addressed to bow instruments. Besides, a catalogue of articulations and ornamentations present in early editions of printed violin music is attached. Last, I comment…
Optimization of image parameters using a hyperspectral library application to soil identification and moisture estimation
2009
The growing number of sensors raises questions about the image parameters required for the application, soil identification and moisture estimation. Hyperspectral images are also known to contain highly redundant information. Hence not all the spectral bands are needed for the satisfactory classification of the soil types. Hence, the work was aimed at obtaining these optimal spectral bands for identifying the soil types and to use these spectral bands to estimate the moisture content of the soils using the method proposed by Whiting et.al.
Learning the relevant image features with multiple kernels
2009
This paper proposes to learn the relevant features of remote sensing images for automatic spatio-spectral classification with the automatic optimization of multiple kernels. The method consists of building dedicated kernels for different sets of bands, contextual or textural features. The optimal linear combination of kernels is optimized through gradient descent on the support vector machine (SVM) objective function. Since a na¨ive implementation is computationally demanding, we propose an efficient model selection procedure based on kernel alignment. The result is a weight — learned from the data — for each kernel where both relevant and meaningless image features emerge after training. E…
Gene connectivity and enzyme evolution in the human metabolic network
2019
[Background] Determining the factors involved in the likelihood of a gene being under adaptive selection is still a challenging goal in Evolutionary Biology. Here, we perform an evolutionary analysis of the human metabolic genes to explore the associations between network structure and the presence and strength of natural selection in the genes whose products are involved in metabolism. Purifying and positive selection are estimated at interspecific (among mammals) and intraspecific (among human populations) levels, and the connections between enzymatic reactions are differentiated between incoming (in-degree) and outgoing (out-degree) links.
Estimating feature discriminant power in decision tree classifiers
1995
Feature Selection is an important phase in pattern recognition system design. Even though there are well established algorithms that are generally applicable, the requirement of using certain type of criteria for some practical problems makes most of the resulting methods highly inefficient. In this work, a method is proposed to rank a given set of features in the particular case of Decision Tree classifiers, using the same information generated while constructing the tree. The preliminary results obtained with both synthetic and real data confirm that the performance is comparable to that of sequential methods with much less computation.
Discussion
1999
Homo sapiens L. has been described as the naked ape, and this nakedness undoubtedly constitutes one of the most striking differences in appearance between man and the apes. Nakedness has been attributed at various times to sexual selection [1], aquatic stage [2], hunting [3], cooling [4], sex [5], neoteny [6] and allometry [7], most proposed explanations logically revealing some aspect of the phenomenon. However, most fail to account for the distinctiveness of man's hairlessness among mammals of the same size. Unfortunately, fossils cannot help us to explain how denudation occurred, and how it helped hominids to survive. In this paper I will present an old hypothesis with a new point of vie…