Cold test simulation method for double-gap output circuit with double coupling apertures

2013 ◽  
Vol 25 (3) ◽  
pp. 675-679
Author(s):  
葛萌 Ge Meng ◽  
王勇 Wang Yong
Methodology ◽  
2017 ◽  
Vol 13 (1) ◽  
pp. 9-22 ◽  
Author(s):  
Pablo Livacic-Rojas ◽  
Guillermo Vallejo ◽  
Paula Fernández ◽  
Ellián Tuero-Herrero

Abstract. Low precision of the inferences of data analyzed with univariate or multivariate models of the Analysis of Variance (ANOVA) in repeated-measures design is associated to the absence of normality distribution of data, nonspherical covariance structures and free variation of the variance and covariance, the lack of knowledge of the error structure underlying the data, and the wrong choice of covariance structure from different selectors. In this study, levels of statistical power presented the Modified Brown Forsythe (MBF) and two procedures with the Mixed-Model Approaches (the Akaike’s Criterion, the Correctly Identified Model [CIM]) are compared. The data were analyzed using Monte Carlo simulation method with the statistical package SAS 9.2, a split-plot design, and considering six manipulated variables. The results show that the procedures exhibit high statistical power levels for within and interactional effects, and moderate and low levels for the between-groups effects under the different conditions analyzed. For the latter, only the Modified Brown Forsythe shows high level of power mainly for groups with 30 cases and Unstructured (UN) and Autoregressive Heterogeneity (ARH) matrices. For this reason, we recommend using this procedure since it exhibits higher levels of power for all effects and does not require a matrix type that underlies the structure of the data. Future research needs to be done in order to compare the power with corrected selectors using single-level and multilevel designs for fixed and random effects.


2015 ◽  
Vol 9 (2) ◽  
pp. 206
Author(s):  
Tawfik Benabdallah ◽  
Nor Nait Sadi ◽  
Mustapha Kamel Abdi

Author(s):  
Л.И. Герасимова-Мейгал ◽  
И.М. Сиренев

Цель исследования - изучение особенностей восприимчивости пациентов с рассеянным склерозом (РС) к холодовому воздействию с помощью функциональных тестов, характеризующих функцию терморегуляции. Как известно, РС - хроническое прогрессирующее аутоиммунное заболевание центральной нервной системы мультифакториальной природы, более часто встречающееся в регионах с холодным и влажным климатом. Нарушения терморегуляции вследствие автономной дисфункции являются характерным признаком РС, вместе с тем участию холодового фактора в развитии заболевания не придается существенного значения. Методика. Обследовано 32 пациента (17 мужчин и 15 женщин, средний возраст 29,6 ± 4,2 года) с установленным диагнозом: РС ремиттирующе-рецидивирующая форма течения (средняя продолжительность заболевания - 4,2 ± 2,7 года) и 18 практически здоровых лиц группы сравнения. Восприятие холода оценивали с помощью визуально-аналоговой шкалы. Продолжительность холод-индуцированной вазоконстрикции после локального холодового теста изучали по данным инфракрасной термометрии. Вегетативную регуляцию вазомоторных реакций оценивали по результатам анализа вызванных кожных вегетативных потенциалов (ВКВП). Результаты. На основе анализа самооценки восприятия холода у пациентов с РС показана низкая переносимость холодового фактора. При проведении локального холодового теста отмечено замедление восстановления температуры кожи кисти, что характерно для усиления холод-индуцированной вазоконстрикции. В группе пациентов с РС выявлено снижение параметров ВКВП ладоней и стоп, свидетельствующее о дефиците нейрогенного контроля терморегуляционных сосудистых реакций. Заключение. У пациентов с РС выявлены нарушения механизмов терморегуляции при действии холода, что обусловливает высокую индивидуальную восприимчивость к холоду у данной категории лиц. Сопоставление результатов анализа механизмов индивидуальной холод-индуцированной реактивности у пациентов с РС с данными эпидемиологических исследований приводит к заключению о потенциальном модулирующем влиянии холодового фактора на течение РС. The purpose of the present study was focused on the evaluation of the sensitivity to cold in multiple sclerosis (MS) patients by means of functional thermoregulatory based tests. MS is known to be a chronic autoimmune progressive disease of the central nervous system of multifactor origin that is very common in regions with cold and humid climate. Disorder of thermoregulation caused by autonomic dysfunction is a typical feature of MS, however the role of the cold in the disease development is still underestimated. Methods. Thirty two MS patients (17 males, 15 females, mean age 29,6 ± 4,2 years) with the remittent form of the disease (mean disease duration 4,2 ± 2,7 years) and 18 age-matched healthy controls volunteered to participate in this study. Susceptibility to cold was analyzed with the use of visual-analogous scale. The duration of cold-induced vasoconstriction after local cold test was estimated using by infrared thermometry. Autonomic regulation of vasomotor reactions was investigated with the help of the skin sympathetic response (SSR) analysis. Results. The analysis of self-reported perception of the cold in MS patients showed their low tolerance to cold. Slow recovery of the skin temperature of the hand in the local cold test observed in MS patients was considered as the aggravated cold-induced vasoconstriction. The decreased SSR in the hands and feet in MS patients was found that indicates the deficit of the neurogenic control of thermoregulatory vasomotor reactions. Conclusion. The results obtained demonstrate the impairment of thermoregulation under cold in MS patients that leads to higher individual susceptibility to cold of this group. Comparing of the data found in this study on the mechanisms of the individual cold-induced reactivity in MS patients with epidemiological surveys enable to conclude that cold environment has potential modulating effect of on the course of MS.


2018 ◽  
Vol 1 (1) ◽  
pp. 120-130 ◽  
Author(s):  
Chunxiang Qian ◽  
Wence Kang ◽  
Hao Ling ◽  
Hua Dong ◽  
Chengyao Liang ◽  
...  

Support Vector Machine (SVM) model optimized by K-Fold cross-validation was built to predict and evaluate the degradation of concrete strength in a complicated marine environment. Meanwhile, several mathematical models, such as Artificial Neural Network (ANN) and Decision Tree (DT), were also built and compared with SVM to determine which one could make the most accurate predictions. The material factors and environmental factors that influence the results were considered. The materials factors mainly involved the original concrete strength, the amount of cement replaced by fly ash and slag. The environmental factors consisted of the concentration of Mg2+, SO42-, Cl-, temperature and exposing time. It was concluded from the prediction results that the optimized SVM model appeared to perform better than other models in predicting the concrete strength. Based on SVM model, a simulation method of variables limitation was used to determine the sensitivity of various factors and the influence degree of these factors on the degradation of concrete strength.


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