• 대한인간공학회:학술대회논문집
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• 대한인간공학회 1995년도 춘계학술대회논문집
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• pp.55-61
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• 1995

We spend about 40% of lifte time on a bed and seek how such amount of time is spent comfort. Bed comfort has been pursuited. The pressure distributions on a bed by body pressure has been considered as one of the most important factors of bed comfort. This study is to quantify the subjective assessment by the body pressure distribution and develop the objective evaluation method of bed comfort. A new measurement system for body pressure on a bed was developed in this study. The thin film pressure sensor (FSR: Force Sensing Resistor) of an elastomer-type was used to prevent the distortion of contact pressure. The pressure distribution is measured by FSR and displayed on the monitor by color-coded contour patterns. Some of the bed test results were described. And the relations between body pressure distribution and bed comfort were evaluated.

• International Journal of Fluid Machinery and Systems
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• 제9권3호
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• pp.237-244
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• 2016

An unsteady three-dimensional simulation based on Reynolds time-averaged governing equation and RNG $k-{\varepsilon}$ turbulence model, was presented for pump-as-turbine, the pressure fluctuation characteristic of hydraulic turbine with guide vane was obtained. The results show that the time domains of pressure fluctuation in volute change periodically and have identical cycles. In volute tongue and inlet pressure fluctuations are light, while in dynamic and static coupling interface pressure fluctuations are serious; In impeller blade region the pressure fluctuation of pressure surface are lighter than that of suction surface. The dominant frequencies of pressure fluctuation concentrate in low frequency region, and concentrate within 2 times of the blade passing frequency.

• 대한조선학회논문집
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• 제46권2호
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• pp.105-113
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• 2009

A theoretical study on the pressure fluctuation induced by a propeller was carried out in this study. The main objective of this study is to analyze the source mechanism of the pressure fluctuation induced by propeller sheet cavitation. To analyze the pressure fluctuation induced by propeller sheet cavitation, modern acoustic theory was applied. Governing equation of pressure fluctuation induced by sheet cavitation was derived using Ffowcs Williams proposed time domain acoustic approaches. Several factors affecting pressure fluctuation were analyzed based on the derived governing equation. Pressure fluctuation result was represented by combined results of the far field term and near field term. Finally, the physical mechanism of pressure fluctuation at the blade rate frequency was analyzed using numerically generated cavitation volume variation.

• 한국정보시스템학회지:정보시스템연구
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• 제31권4호
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• pp.209-232
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• 2022

Purpose In the current environment of online shopping, the cost for consumers to obtain the information they need is decreasing, and the price of products is becoming more transparent, leading to increased price competition among enterprises for similar products. Given the widespread usage of limited-time promotion as a marketing method for enterprises in the context of e-commerce, it is great meaning to study and reveal the internal influence mechanism of limited-time promotion on consumers' impulsive consumption. Design/methodology/approach Based on the S-O-R theory, this study constructs a model of consumers' impulsive consumption in the context of e-commerce from the perspective of perceived price discount, with evoking sense and pleasure as mediating variables and perceived time pressure as moderating variables. Findings The results show that perceived price discount has a significant positive impact on evoking sense and pleasure. Evoking sense has a significant positive impact on pleasure. Both evoking sense and pleasure have a significant positive impact on consumers' impulsive consumption. Meanwhile, perceived time pressure plays a significant moderating role between perceived price discount and evoking sense, between perceived price discount and pleasure, and between evoking sense and consumers' impulsive consumption. Finally, based on the above findings, this study provides effective suggestions for e-commerce participants in the formulation of limited-time promotion strategies.

• 동아시아식생활학회지
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• 제23권2호
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• pp.203-210
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• 2013

In this study, cod bone were used as the main ingredient of a stock that can be eaten with Korean dried noodles. The stock was produced with heating for 30, 40, 50, 60, or 70 minutes using high-pressure extraction methods. Moisture content, chromaticity, pH, sugar content, salinity, mineral contents, quantitative analysis, and overall acceptance were studied to determine the optimal heating time. In our result, S1 the showed highest water contents 98.10%, while S5 showed the lowest moisture content (97.47%). There were no significant difference in pH between samples, while salinity and sugar content increased with increases in heating time. In terms of mineral contents, sodium and potassium showed proportional difference with increases in heating time, however, magnesium, calcium, and iron did not change. The results from a quantitative analysis test showed that transparency, fishy smell, delicate flavor, savory flavor, salt taste, and umami taste became stronger with increases in heating time increase. From the above results, the overall taste of the stock increases with increases in high-pressure heating time. Specifically, S4 high-pressure heating scored the highest on appearance, flavor, taste, after-taste, and overall acceptance. Thus, 60 minutes of high-pressure heating time is most desirable when producing stock with cod bones as a main ingredient.

• 한국전기전자재료학회논문지
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• 제26권9호
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• pp.669-676
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• 2013

In this study, we introduce a polymer(polyimide) based pressure sensor to measure real-time heart beat and blood pressure. The sensor have been designed with consideration of skin compatibility of material, cost effectiveness, manufacturability and wireless detection. The designed sensor was composed of inductor coils and an air-gap capacitor which generate self-resonant frequency when electrical source is applied on the system. The sensor was obtained with metalization, etching, photolithography, polymer adhesive bonding and laser cutting. The fabricated sensor was shaped in circular type with 10mm diameter and 0.45 mm thickness to fit radial artery. Resonant frequencies of the fabricated sensors were in the range of 91~96 MHz on 760 mmHg pressurized environment. Also the sensor has good linearity without any pressure-frequency hysteresis. Sensitivity of the sensor was 145.5 kHz/mmHg and accuracy was less than 2 mmHg. Real-time heart beat measurement was executed with a developed hand-held measurement system. Possibility of real-time blood pressure measurement was showed with simulated artery system. After installation of the sensor on skin above radial artery, simple real blood pressure measurement was performed with 64 mmHg blood pressure variation.

• 한국추진공학회지
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• 제16권1호
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• pp.1-8
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• 2012

희석된 수소-공기 확산화염의 응향 응답 특성을 저압과 고압 영역에서의 화염 구조 해석을 토대로 수치적으로 조사하였다. 음향 주파수가 증가함에 따라 어느 압력 영역에서든 열방출율의 비선형 축적현상에 의해 유한 화학반응의 효과가 증진된다. 이는 결국 높은 음향 증폭으로 이어지게 된다. 동일한 계산 결과를 압력 감응 시간지연 모델에 의해 재해석하였다. 시간 지연 모델의 적절한 적용을 통해, 각 압력 영역에서 시간지연과 간섭지수 인자가 정량화되었다. 음향 증폭의 정도를 나타내는 간섭지수는 어느 압력 영역에서든 1000 Hz 근처에서 최고값을 나타내었고, 고압영역에서 화염이 더 불안정한 응답을 보였다. 음향 주파수에 따른 간섭지수의 변화 경향은 기존의 증폭지수 변화 경향과 잘 일치하였다.

• 대한후두음성언어의학회지
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• 제7권1호
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• pp.50-55
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• 1996

Acoustic analysis study was performed on 20 normal subjects by speaking nonsense syllables composed of Korean bilabial stops$(/P, P^{\star}, P^{h}/)$ and their preceding and/or following vowel /a/ (that is, $[pa, p^{\star}a, p^{h}a, apa, ap^{\star}a, ap^{h}a]$) with an ultraminiature pressure, sensor. in their mouths. Speech materials were phonated twice, once with a moderate voice, another time with a loud voice. The acoustic signal and intraoral pressure were recorded simultaneously on computer. By these procedures, we were to measure the intraoral pressure, closure duration and VOT of Korean bilabial stops, and to compare the values one another according to the intensity of phonation and the position of the target consonants. Intraoral pressure was measured by the peak intraoral pressure value of Its wave closure duration by the time interval between the onset of intraoral pressure build-up and the burst meaning the release of closure ; Voice onset time(VOT) on by the time interval between the burst and the onset or glottal vibration. Heavily aspirated bilabial stop consonant /$p^h$/ showed the highest intraoral pressure value, unaspirated /$p^{\star}$/, the second, slightly aspirated /P/, the lowest. The syllable initial bilabial stops showed higher intraoral pressure than word initial stops, and the value of loudly phonated consonants were higher than moderate consonants. The longest closure duration period was that of /$p^{\star}$/ and the shortest, /P/, and the duration was longer in word initial position and in the moderate voice. In VOT, the order of the longest to shortest was $/{p^h}/, /p/, /{p^\star}/$, and the value was shorer when the consonant was in intervocalic position and when it was phonated with a loud voice.

• 대한한의학회지
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• 제34권4호
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• pp.12-20
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• 2013

Objectives: This study compared Gumiganghwal-tang (GGT) decoctions produced using different pressure levels for various extraction times to determine the optimal extraction conditions through hydrogen ion concentration (pH), total soluble solids content (TSSC), extraction yield, and content of chemical compounds. Methods: Decoctions were prepared by the pressure levels of 0 or $1kgf/cm^2$ for 30-180 min. The pH and TSSC were measured, the extraction yield was calculated, and the amounts of the chemical compounds were determined using high performance liquid chromatography. Results: The higher pressure and longer extraction time decreased the pH value, while those conditions increased TSSC and extraction yield: the decoction produced in 180 min by pressurized method showed the minimum value of pH, but maximum values of TSSC and extraction yield. The chemical compounds showed higher amounts in decoctions produced by non-pressurized methods than pressurized methods and their amounts were decreased over the peak extraction time in both pressurized and non-pressurized methods. The results of regression analysis confirmed the correlative influences of the pressure and extraction time on pH, TSSC, and extraction yield. Conclusions: This study suggests that pressure and extraction time influence the compositional constituents in GGT decoctions, and the non-pressurized method for 120 min should be chosen as the optimal extraction condition for the preparation of GGT decoction.

• 대한한의학방제학회지
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• 제22권2호
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• pp.15-24
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• 2014

Objectives : Gwakhyangjeonggi-san (GJS) which consists of 13 herbal medicines has been used to treat gastrointestinal disorders caused by common cold. This study was performed to compare GJS decoctions produced using different pressure levels for various extraction times. Methods : Decoctions were prepared by the pressure levels of $0kgf/cm^2$ (non-pressurized) or $1kgf/cm^2$ (pressurized) for 30-180 min. The extraction yield, total soluble solid content (TSSC), and hydrogen ion concentration (pH) were measured, and the contents of the nine marker compounds were determined using high performance liquid chromatography. Results : The higher pressure and longer extraction time significantly increased TSSC value, while decreased the pH value. However, only extraction time affected the extraction yield of pressurized decoction. Variation of the amounts of chemical compounds was shown in pressurized and non-pressurized decoctions during extraction time. The result of regression analysis showed that pressure and extraction time can influence to extraction yield, TSSC, pH, and the content of chemical compounds. Conclusions : This study suggests that the pressure and extraction time can significantly affect the extraction efficiency of components from GJS decoctions.