Study On Pressure Comfort In Wearing A Waist-Nipper On The Basis Of Human’s Heart Rate Variability And Electroencephalogram

In the study of clothing comfort performance, evaluation of wearing pressure comfort is very important, particularly for the foundation garment.Up to now, wearing pressure comfort is usually evaluated by objective measurement of clothing pressure, together with subjective pressure comfort ratings. Wearing pressure comfort performance is determined by both the clothing pressure and human’s physiological, psychological factor, and therefore, only physical mechanics performance is attained by objective measurement of clothing pressure. Subjective pressure comfort ratings are of little objective physiological significance and at the same time, they are greatly influenced by human’s subjective factor.Physiologically, human’s physiological parameters can be regarded as the essential evaluation index of skin pressure sensation. If the evaluation of wearing pressure comfort is based on the variation of human’s physiological reaction while they feel comfortable or uncomfortable, it will be more objective. And moreover, by introducing the human’s physiological parameters, the evaluation result is of physiological significance.Therefore, in this study, human’s electrophysiological parameters-heart rate variability (HRV) and electroencephalogram (EEG) were proposed to objectively evaluate wearing pressure comfort. By analyzing the effect of skin pressure on HRV and EEG. mechanism of skin pressure comfort was elucidated. Furthermore, the pressure comfort prediction model of wearing a waist-nipper on the basis of skin pressure, index of HRV and EEG was developed. The present work was described as follows:(1) The skin extending from lower breast to lower abdomen was selected, which was sensitive for the skin pressure sensation, and three kinds of waist-nippers were chosen to be as the samples of foundation garments. By the subjects’ wear trial, clothing pressure caused by the waist-nippers was measured, and impossible influence factors affecting clothing pressure were studied. Finally, where the local skin pressure was the largest was found to be the subjects’lower abdomen and lateral waist. (2) To objectively evaluate the body modification effect of the three kinds of waist-nippersBy [TC]23D body scan and measurement system, the subjects’feature size of five feature parts was extracted before and after wear trial for comparing the enhancement effect. The five feature parts included the subjects’ breast, lower breast, waist, lower abdomen and hip. The extracted feature size of each feature part included circumference, breadth, depth and area. Horizontal cross-section of each feature part was extracted further to qualitatively evaluate the body modification effect of the three styles of waist-nippers.(3) To carry out an experiment on the physiological reaction for analyzing the effect of skin pressure on human’s HRV and EEG activityBy means of RM6240C Multi-channel Physiological Signals Acquiring System, the skin pressure measuring instrument was made, which was used to control the magnitude of skin pressure exerted on the torso. Base on it. an experiment was carried out to investigate the effect of incremental skin pressure on the HRV and EEG activity in healthy young women. According to the result, significant regulations were found that how skin pressure influenced human’s HRV and EEG activities. Relations of skin pressure to both physiological parameters and psychological sensation were analyzed. And a theoretical study of the mechanism of skin pressure comfort was discussed. And as a result, comfort threshold of skin pressure on the lower abdomen and on the lateral waist was found. Finally, skin pressure comfort index was established according to the subjective comfort ratings.(4) To establish comfort grades of the skin pressureFactor analysis was used within HRV and EEG variables to identify’the factors which could explain the correlation of a serial of variables. As a result, two factors were obtained, which were physiological comfort factor and psychological comfort factor. Based on the factor score and subjective ratings of skin pressure sensor)1comfort, the optimal segmentation method for orderly samples was made to classify the data. And according to the result of significant classification, the grades of skin pressure comfort were established objectively, which were "excellent","good" and "bad".(5) To develop prediction models to predict wearing pressure comfortThree kinds of machine learning methods. BPNN (back propagation neural network). SVM (support vector machine) and RF (random forest), were used to forecast the index of wearing pressure comfort. In the prediction models, skin pressure on the lower abdomen or on the lateral waist. HRV and EEG parameters were chosen as independents, and skin pressure comfort index was as dependent. The forecasting performance of the three models was checked by correlation analyzing method.(6) To validate the models by carrying out the further experimentA confirmatory test was carried out by the subjects’wear trial. By analyzing HRV and EEG variables when the subjects were wearing the three kinds of waist-nippers, one of the aims was to validate the significant regulations that how skin pressure influenced human’s HRV and EEG activities, the other is to validate the three prediction models, and finally preference was made by comparing the prediction accuracy of the three models.In the thesis, the innovation was described as follows:(1) The effect of skin pressure on human’s HRV and EEG activity was first investigated. It provided a new idea for assessing wearing pressure comfort objectively.(2) A skin pressure measuring instrument was made, which could control the magnitude of skin pressure on the human body. It provided the technical method and basic theory for further research on clothing pressure comfort.(3) Three kinds of advanced machine learning methods, BPNN. SVM and RF, were used to develop the model in the prediction of wearing pressure comfort, based on a series of variables including skin pressure, human’s physiological and neurophysiologic parameters. It made a connection among the science of physics, physiology, psychology and statistics.The project is financially supported by the research Fund for the Doctoral Program of Higher Education of China,2006(RFDP).