Search results for " Selection"
showing 10 items of 1271 documents
Chronic Mesenteric Ischemia: Critical review and guidelines for management
2011
Background CMI is caused by chronic occlusive disease of mesenteric arteries. In such an uncommon disease, clear recommendations are strongly needed. Unfortunately, treatment options for symptomatic CMI are still controversial and no guidelines exist. Methods A systematic literature review of the last 25-years was conducted through MEDLINE, Embase, and Cochrane Review/Trials register to identify studies reporting on CMI treatment with more than 10 patients. Primary outcomes were perioperative mortality and morbidity rates. Secondary outcomes were survival rates, primary and secondary patency rates, vessels treated, CMI recurrence, follow-up (FU), technical success (TS), and in-hospital leng…
Effects of microclimate on nest site selection and breeding success of lesser kestrel Falco naumanni in the Gela Plain (Sicily)
2013
Ecologists overestimate the importance of predictor variables in model averaging: a plea for cautious interpretations.
2014
Abstract: Information-theory procedures are powerful tools for multimodel inference and are now standard methods in ecology. When performing model averaging on a given set of models, the importance of a predictor variable is commonly estimated by summing the weights of models where the variable appears, the so-called sum of weights (SW). However, SWs have received little methodological attention and are frequently misinterpreted. We assessed the reliability of SW by performing model selection and averaging on simulated data sets including variables strongly and weakly correlated to the response variable and a variable unrelated to the response. Our aim was to investigate how useful SWs are …
Model selection procedure for mixture hidden Markov models
2021
This paper proposes a model selection procedure to identify the number of clusters and hidden states in discrete Mixture Hidden Markov models (MHMMs). The model selection is based on a step-wise approach that uses, as score, information criteria and an entropy criterion. By means of a simulation study, we show that our procedure performs better than classical model selection methods in identifying the correct number of clusters and hidden states or an approximation of them
Clickstream Data Analysis: A Clustering Approach Based on Mixture Hidden Markov Models
2023
Nowadays, the availability of devices such as laptops and cell phones enables one to browse the web at any time and place. As a consequence, a company needs to have a website so as to maintain or increase customer loyalty and reach potential new customers. Besides, acting as a virtual point-of-sale, the company portal allows it to obtain insights on potential customers through clickstream data, web generated data that track users accesses and activities in websites. However, these data are not easy to handle as they are complex, unstructured and limited by lack of clear information about user intentions and goals. Clickstream data analysis is a suitable tool for managing the complexity of t…
Factor selection procedures in a Google Earthtm aided landslide susceptibility model: application to the Beiro river basin (Spain)
2011
A procedure to select the controlling factors connected to the slope instability has been defined. It allowed to assess the landslide susceptibility in the Rio Beiro basin (about 10 km2) over the north-eastern area of the city of Granada (Spain). Field and remote (Google EarthTM) recognition techniques allowed to generate a landslide inventory consisting in 127 phenomena. Univariate tests, using both association coefficients and validation results of single parameter susceptibility models, allowed to select among 15 controlling factors the ones that resulted as good predictor variables; these have been combined for unique conditions analysis and susceptibility maps were finally prepared. In…
Differences in estimates of change of bone accrual and body composition in children because of scan mode selection with the prodigy densitometer.
2004
Abstract Girls of age 10–13 yr with Tanner stage I–III maturation status ( n = 155) were measured using the Prodigy (GE Lunar) densitometer. Bone area (BA), bone mineral content (BMC), and bone mineral density (BMD) were assessed for the whole body, lumbar spine, and proximal femur using the Thin (T) and Standard (S) scan modes at years 1 and 3 of the study. The differences obtained between the T and S mode at year 1 were 1–2% for the lumbar spine and proximal femur and 5–11% for the whole body. For those girls whose default mode changed from T at year 1 to S mode at year 3, the estimated gain in BA, BMC, and BMD was 3.4%, 7.6%, and 3.1% respectively, lower than that obtained when scanning …
La selección de las noticias en el entorno de un centro de documentación de información de actualidad
2002
In information retrieval systems operation, lack of adequate selection criteria originates information overload and has negative consequences in relevance judgments. In the context of a news reference service, three leveis in the selection process are proposed. The first one relates to the type of sources covered by the system, the second set of criteria determines which publications are included in the process of document analysis. The last one applies to the selection of individual documents based on their informative content. La falta de criterios idóneos de selección puede provocar un grave problema de saturación informativa, lo que repercute negativamente en la búsqueda posterior de in…
Extracting multi-mode ERP features using fifth-order nonnegative tensor decomposition
2018
Background Preprocessed Event-related potential (ERP) data are usually organized in multi-way tensor, in which tensor decomposition serves as a powerful tool for data processing. Due to the limitation of computation burden for multi-way data and the low algorithm performance of stability and efficiency, multi-way ERP data are conventionally reorganized into low-order tensor or matrix before further analysis. However, the reorganization may hamper mode specification and spoil the interaction information among different modes. New method In this study, we applied a fifth-order tensor decomposition to a set of fifth-order ERP data collected by exerting proprioceptive stimulus on left and right…