• Journal of the Korean Society for Railway
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• v.7 no.3
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• pp.200-207
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• 2004

Theoretical study has been conducted to clarify pressure characteristics of KTX (Korea Train eXpress) in tunnel. The severe pressure change in tunnel may give rise to the ear-discomfort for passenger and fatigue for car body. Critical tunnel lengths which are induced by x-t diagram analysis can be applied to the experimental results measured by using the running test with atmospheric pressure sensors and portable data acquisition system in previous study. In this study, the tunnels from 200m to 4000m in length have been chosen for the investigation of tunnel length effects. We found that there are similar patterns of external pressure change for each critical tunnel length. The critical tunnel lengths are governed by train speed, train length and sonic velocity. And, the patterns of pressure wave in tunnel are classified into eight groups.

• Journal of Korean Biological Nursing Science
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• v.24 no.3
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• pp.190-199
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• 2022

Purpose: This study investigated the effect of pressure injury nursing knowledge, and pressure injury nursing attitudes, on pressure injury nursing practice. Methods: Participants in this descriptive study were 141 nurses at 20 geriatric hospitals. Data was collected August 24, 2021- April 4, 2022, and analyzed in terms of Independent t-test and one-way ANOVA, Scheffé test, Pearson's correlation coefficient, and multiple regression, using the SPSS/WIN 27.0 program. Results: Pressure injury nursing practice positively correlated with pressure injury nursing attitudes (r= .44, p< .001). Factors influencing pressure injury nursing practice were pressure injury nursing attitudes (β= .43, p< .001), and gender (β= .21, p= .006). The model used in this study explains 22.8% of pressure injury nursing practice (Adjusted R²= 22.8, F= 11.30, p< .001). Conclusion: Results show factors that influence pressure injury nursing practice of nurses in geriatric hospitals. Based on the results, pressure injury nursing practice programs must include factors that improve pressure injury nursing attitudes. A follow-up study to confirm the impact of developing a program for increasing pressure injury nursing practice is also recommended.

• Journal of the Ergonomics Society of Korea
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• v.31 no.3
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• pp.455-461
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• 2012

The aim of this study was to investigate the appropriate elasticity of the textile material used for making women's girdle. Background: The elastic textiles have been used for making girdle. The hard type girdle gave high pressure on the body to make slim look. However, excessively high garment pressure caused negative effect to human bodies. This study studied the material giving proper garment pressure in girdle. Method: In this study five experimental girdles were made fabrics with various elasticities. The change of garment pressures and body girths were measured after subjects wearing the experimental girdles. The garment pressure was measured at 10 points. Body girths measured at abdomen, hip, and thigh. Results: The garment pressure of the commercial girdle was high at side of waistband, side femur and back gluteal fold. The experimental girdles made with high elasticity material definitely lowered garment pressure at those points. After wearing experimental girdle their abdomen and hip girths measurements were decreased. But, thigh girth was not reduced. Conclusion: The girdle made with excellent elasticity materials reduced garment pressure significantly and it made body slim as much as the commercial girdle except the thighs. Application: This study provides guideline for the developing girdle that applying optimum range of garment pressure with body slim effect.

• Journal of Preventive Medicine and Public Health
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• v.24 no.2 s.34
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• pp.161-170
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• 1991

The purpose of this study is to find the tracking of blood pressure in primary school-age children. A follow-up study was conducted from 1986 to 1990 on 330 first grade children attending primary schools in Kangwha County, Kyungki-Do. Basically we employed a linear regression model with random coefficients to figure out the relation between blood pressure changes and initial blood pressure. We obtained the following results ; 1. The mean blood pressures were increased grade went up in both sexs and were generally higher in female than male except for the systolic blood pressure at first grade. The size of difference was about 0.8 mmHg in mean systolic blood pressure and 1.5 mmHg in mean diastolic blood pressure. 2. The average annual increasing rates of systolic blood pressure were 2.5 mmHg in male and 3.1 mmHg in female respectively. For the diastolic blood pressure IV the average annual increasing rates were observed to be 3.0 mmHg in male and 2.9 mmHg in female respectively. Increasing rate of systolic blood pressure was significantly higher in female than male. 3. The adjusted regression coefficient of systolic blood pressure change on initial value was -0.11 in male and -0.13 in female and that coefficient of diastolic blood pressure change on initial value was -0.01 in male and -0.11 in female. This result shows that children with higher initial blood pressure do not pick up their blood pressure faster than others with lower initial blood pressure. There is no evidence of tracking of blood pressure in children. It is essential to find the earliest age having the tracking of blood pressure and we leave it for the further study.

• Journal of Preventive Medicine and Public Health
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• v.26 no.1 s.41
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• pp.96-109
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• 1993

For the purposes of analyzing the distribution and the change in blood pressure according to age and determining the factors affecting the change in blood pressure, a follow-up study had been conducted for 6 years from 1986 to 1991 for 430 primary school children aged 6 years old in 1986 in Kangwha County, Korea. The mean blood pressure increased according to age. Specifically mean systolic blood pressure increased from 97.3 mmHg for male and 96.4mmHg for female (at 6 years of age) to 108.8mmHg fur male and 112.1mmHg for female (at 11 years of age). Mean diastolic blood pressure increased from 60.0mmHg for male and 61.8mmHg for female (at 6 years of age) to 72.9mmHg for male and 73.8mmHg for female (at 11 years of age). The average annual increase in blood pressure was 2.3mmHg (in systolic blood pressure) and 2.6 mmHg (in diastolic blood pressure) for male : and 3.1mmHg (in systolic blood pressure) and 2.4mmHg (in diastolic blood pressure) for female, respectively. To determine the factors affecting the change in blood pressure, the stepwise regression analysis was conducted. Children were divided into the three groups(low, middle, and upper) according to the level of systolic and diastolic blood pressure at the age of 6, and the regression analysis was performed in each group. For the change in systolic blood pressure, the changes in weight and skinfold thickness or initial skinfold thickness fer male, and the change in weight for female were selected as significant factors for children in middle and upper group. For the change of blood pressure in diastolic blood pressure, no variables was significant.

• Geomechanics and Engineering
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• v.5 no.1
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• pp.1-15
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• 2013

Pressure transducers are increasingly used within soil mass or at soil-structure interface for appraisal of stresses acting at point of installation. Calibration of pressure transducers provides a unique relationship between applied pressure and voltage or strain sensed by transducer during various loading conditions and is crucial for proper interpretation of results obtained from pressure transducers. In the present study an in-house calibration device is used to calibrate pressure transducers and the study is divided into two parts: 1) demonstration of developed calibration device for fluid and in-soil calibration of pressure transducers; 2) effect of soil layer thickness on the earth pressure cell (EPC) output. Results obtained from the present study revealed successful performance of the developed calibration device, and significant effect of sand layer thickness on the calibration results. The optimum sand layer thickness is obtained as 1.5 times the diameter of EPC.

• Journal of Korean Society of Water and Wastewater
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• v.16 no.6
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• pp.726-732
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• 2002

Pressure drop could happen in the water distribution systems due to pipe breaks or maintenance. The pressure drop causes the water service shutdown and nodal water demands should be reduced in some areas. The conventional analysis method of water distribution systems can not consider the change of nodal water demands caused by these pressure drops. This study is to investigate the variation of nodal water demands according to the nodal water pressure and its effect on the analysis of water distribution systems. For these purpose, one real water service district was selected as a study area. As a result, nodal water demand patterns according to the water pressure could be suggested. Also, we could confirm that the suggested new analysis method for the water distribution systems which considering water pressure drops could be more reliable than the conventional method.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.281-286
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• 2003

Experimental study is conducted to clarify the inside and outside pressure variation of passenger cabin for KTX. These pressure variation may give rise to the ear-discomfort. Generally ear-discomfort has been considered as a problem related to high speed train. In this study, the pressure variation of interior, gangway and exterior of KTX passenger car is measured by using the atmospheric pressure sensors and portable data acquisition system. The tunnel from 4000m to 200m in length are chosen for the investigation of length effects. From the results of experiment, the pressure variation of interior per second is under the ear-discomfort limitation in all of tunnel. And, We found that there is a similar pattern of exterior pressure variation. These results generally agree with RTRI's experimental result for Shinkansen.

• Structural Engineering and Mechanics
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• v.6 no.6
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• pp.711-725
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• 1998

Mixed finite element formulations for incompressible materials show pressure oscillations or pressure modes in four-node quadrilateral elements. The criterion for the stability in the pressure solution is the so-called Babu$\check{s}$ka-Brezzi stability condition, and the four-node elements based on mixed variational principles do not appear to satisfy this condition. In this study, a pressure continuity residual based on the pressure discontinuity at element edges proposed by Hughes and Franca is used to study the stabilization of pressure solutions in bilinear displacement-constant pressure four-node quadrilateral elements. Also, a solid mechanics problem is presented by which the stability of mixed elements can be studied. It is shown that the pressure solutions, although stable, are shown to exhibit sensitivity to the stabilization parameters.

• Journal of Computing Science and Engineering
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• v.2 no.2
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• pp.180-199
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• 2008

Technology has had a tremendous impact on our daily lives. Recently, technology and its impact on aging has become an expanding field of inquiry. A major reason for this interest is that the use of technology can help older people who experience deteriorating health to live independently. In this paper we give a brief review of the in-home monitoring technologies for the elderly. In the pilot study, we analyze the possibility of employing the data generated by a continuous, unobtrusive nursing home monitoring system for predicting elevated(abnormal)pulse pressure(PP) in elderly(PP=systolic blood pressure-diastolic blood pressure). Our sensor data capture external information(behavioral) about the resident that is subsequently reflected in the predicted PP. By continuously predicting the possibility of elevated pulse pressure we may alert the nursing staff when some predefined threshold is exceeded. This approach may provide additional blood pressure monitoring for the elderly persons susceptible to blood pressure variations during the time between two nursing visits. We conducted a retrospective pilot study on two residents of the TigerPlace aging in place facility with age over 70, that had blood pressure measured between 100 and 300 times during a period of two years. The pilot study suggested that abnormal pulse pressure can be reasonably well estimated (an area under ROC curve of about 0.75) using apartment bed and motion sensors.