Search results for "Model"
showing 10 items of 24058 documents
Comparison of Machine Learning Methods in Stochastic Skin Optical Model Inversion
2020
In this study, we compare six different machine learning methods in the inversion of a stochastic model for light propagation in layered media, and use the inverse models to estimate four parameters of the skin from the simulated data: melanin concentration, hemoglobin volume fraction, and thicknesses of epidermis and dermis. The aim of this study is to determine the best methods for stochastic model inversion in order to improve current methods in skin related cancer diagnostics and in the future develop a non-invasive way to measure the physical parameters of the skin based partially on the results of the study. Of the compared methods, which are convolutional neural network, multi-layer …
Analysis of a database to predict the result of allergy testing in vivo in patients with chronic nasal symptoms.
2014
Background This article uses the logistic regression model for diagnostic decision making in patients with chronic nasal symptoms. We studied the ability of the logistic regression model, obtained by the evaluation of a database, to detect patients with positive allergy skin-prick test (SPT) and patients with negative SPT. The model developed was validated using the data set obtained from another medical institution. Methods The analysis was performed using a database obtained from a questionnaire administered to the patients with nasal symptoms containing personal data, clinical data, and results of allergy testing (SPT). All variables found to be significantly different between patients w…
Markova modeļu pielietojums notikumu vēstures pētīšanai
2020
Notikumu vēstures pētīšana ir iespējama ar vairākām metodēm, bet šajā darbā vairāk tiks apskatīta Markova modeļu pielietošana, sākot ar pirmo šādu modeli Neimaņa-Fiksa modeli un turpinot ar šobrīd aktuālajiem- divu stāvokļu modeli, konkurējošo risku modeli, slimības-nāves modeli. Vēl bez modeļiem tiks sniegta arī statistikas modeļu specifikācija un vairāki pielietojuma piemēri.
Small area estimation with linear mixed models from unit-level panel and rotating panel data
2009
Commentary: Long-term Practice with Domain-Specific Task Constraints Influences Perceptual Skills.
2018
Smilts-grants un smilts atradņu krājumu aprēķinu metodes
2019
Pētījuma mērķis ir analizēt smilts-grants un smilts krājumu izmaiņas, salīdzinot Latvijā populārākās aprēķinu metodes ar trīsdimensionālo modelēšanu datorvidē. Precīza derīgo izrakteņu tilpumu aprēķināšanas metodika ir svarīga gan derīgo izrakteņu izstrādātājam, gan izstrādi regulējošajām valstiskajām institūcijām. Iepriekšējie pētījumi analizēja derīgo izrakteņu krājumu izmaiņas, izmantojot divdimensionālos slāņu virsmu modeļus, savukārt šajā pētījumā tiek analizēta jauna pieeja sarežģītas uzbūves smilts-grants un smilts atradņu krājumu aprēķināšanā, izmantojot slāņu saguluma trīsdimensionālo modelēšanu. Pētījuma rezultātā krājumi tika aprēķināti gan ar trīsdimensionālajiem modeļiem, gan a…
Splines in convex sets under constraints of two‐sided inequality type in a hyperplane
2008
The problem of minimization of a smoothing functional under inequality constraints is considered in a hyperplane. The conditions of the existence of a solution are obtained and some properties of this solution are investigated. It is proved that the solution is a spline. The method for its construction is suggested. First Published Online: 14 Oct 2010
Distribución de la humedad del suelo mediante observaciones del satétite SMOS, modelización con SURFEX y medidas in situ sobre la Valencia Anchor Sta…
2017
La humedad del suelo es una variable importante en agricultura, hidrología, meteorología y disciplinas afines. A pesar de su importancia, es complicado obtener una representación adecuada de esta variable, principalmente por su alta variabilidad temporal y espacial. Las observaciones in situ son escasas, pero los modelos SVAT (Soil-Vegetation-Atmosphere-Transfer) pueden utilizarse para simular el comportamiento temporal y la distribución espacial de la humedad del suelo en un área determinada. El objetivo principal de esta tesis es generar campos de humedad del suelo que permitan la espacialización de las medidas puntuales de las estaciones de la Valencia Anchor Station y para ello se utili…
Social engagement from childhood to middle age and the effect of childhood socio-economic status on middle age social engagement: results from the Na…
2016
ABSTRACTSocial engagement has powerful effects on wellbeing, but variation in individual engagement throughout the lifecourse is wide. The trajectories may differ by gender and be affected by socio-economic status (SES). However, long-term development of social engagement is little studied and the effect of childhood SES on later-life social engagement remains obscure. We aimed to describe the social engagement development from childhood to middle age by gender and test the effect of childhood SES on middle age social engagement. Data (N=16,440, 51.3% male) are drawn from the on-going National Child Development Study, following British babies born in 1958. Social engagement was measured by …
Reciprocal Relationships Between Perceived Supportive School Climate and Self-reported Truancy : A Longitudinal Study from Grade 6 to Grade 9
2022
This longitudinal study of 1,066 Finnish students examined bidirectional reciprocal relationships between changes in perceived supportive school climate and changes in self-reported truancy from the last year of primary school (Grade 6) to the last year of lower secondary school (Grade 9). The results of the random intercept cross-lagged panel model showed, first, that a decrease in positive perceptions of school climate at the previous time point predicted more self-reported truancy at the following time point. Second, an increase in self-reported truancy predicted less positive perceptions of supportive school climate. The study indicates that students’ perceptions of supportive school cl…