• The Journal of Korean Academy of Prosthodontics
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• v.24 no.1
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• pp.33-43
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• 1986

The purpose of this study was to compare the wear resistance of heat pressure-cured microcomposite(SR-Isosit-N), photo-cured microcomposite(Dentalcolor), unfilled heat-cured resin(Thermojel) and that of human enmel. Specimens were made with specially designed die and finally polished with #3,000 diamond paste. After 100,000 strokes of tooth brushing at electric tooth-brushing machine, mean thickness loss of each specimen was measured by using surface profile and integration. The results were as follows 1. Mean thickness loss were $84.3{\pm}27.3{\mu}m$ in unfiled heat-cured resin, $9.4{\pm}2.5{\mu}m$ in photocured microcomposite, $7.6{\pm}2.1{\mu}m$ in heat.pressure-cured microcomposite and $0.97{\pm}0.42{\mu}m$ in enamel. 2. Heat.pressure-cured microcomposite and photo-cured microcomposite had no difference in mean thickness loss(p>0.05). 3. Unfilled resin and microcomposite had much differences in mean thickness loss (p<0.005). 4. ha resins used in this experiment had too much mean thickness loss as compared with enamel (p<0.005).

• Journal of ILASS-Korea
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• v.10 no.4
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• pp.47-53
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• 2005

This paper presents the effects of ambient pressure on atomization characteristics of high-Pressure injector in a direct injection gasoline engine both experimentally and numerically. The atomization characteristics such as mean droplet size, mean velocity, and velocity distribution were measured by phase Doppler particle analyzer. The spray development, spray penetration, and global spray structure were visualized using a shadowgraph technique. In order to investigate the atomization process numerically, the LISA-DDB hybrid model was utilized. This breakup model assumes that the primary breakup occurs when the amplitude of the unstable waves is equal to the radius of the ligament of liquid sheet near the nozzle and the droplet deformation induces the secondary breakup. The results provide the effect of ambient pressure on the macroscopic and microscopic behaviors such as spray development, spray penetration, mean droplet size, and mean velocity distribution. It is also revealed that the accuracy of prediction of LISA-DDB hybrid model is pretty good in terms of spray developing process, spray tip penetration, and SMD distribution.

• Journal of Korean Physical Therapy Science
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• v.10 no.2
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• pp.96-103
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• 2003

The purpose of this study was to assess the effect of applied pressure to abdomen on lumbar and abdominal muscle activation during upper limb exercise. The experimental group consisted of twenty-seven healthy male subjects (mean age=$22.40{\pm}2.19years$, mean height=$175.30{\pm}2.19cm$, mean weight= $67.67{\pm}7.44kg$, RM=$8.43{\pm}2.76kg$). In each different pressure condition (OmmHg, 30mmHg, 70mmHg, 100mmHg), upper limb exercise was performed in total of 10 trials with 10 RM dumb-bell exercise. Lumbar and abdominal muscle activity was measured using surface bipolar electrode electromyography(EMG). EMG activity was measured from upper rectus abdominis, external oblique abdominis, internal oblique abdominis, and elector spinae. The raw EMG signal was processed into the root mean square(RMS). All RMS EMG data were normalized and express as a percentage of the EMG(%EMG). Collected data were statistically analyzed by SPSS/PC Ver 10.0 using two-way analysis of variance for repeated measures($4{\pm}3$) and Bonferroni post hoc, test. Lumbar and abdominal muscle activation was significantly increased when 100 mmHg was applied(p<.05). Upper rectus abdominis activation was significantly increased compared as other muscles activation(p<.05). However, there were no interaction between pressure and muscles(p>.05). The findings of this study can be used as a fundamental data when lumbar orthosis is applied and external pressure can be used as a therapeutic tool.

• The Journal of Society for e-Business Studies
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• v.23 no.2
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• pp.33-47
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• 2018

City gas pipelines are buried underground. Because of this, pipeline is hard to manage, and can be easily damaged. This research proposes a real time prediction system that helps experts can make decision about pressure anomalies. The gas pipline pressure data of Jungbu City Gas Company, which is one of the domestic city gas suppliers, time variables and environment variables are analysed. In this research, regression models that predicts pipeline pressure in minutes are proposed. Random forest, support vector regression (SVR), long-short term memory (LSTM) algorithms are used to build pressure prediction models. A comparison of pressure prediction models' preformances shows that the LSTM model was the best. LSTM model for Asan-si have root mean square error (RMSE) 0.011, mean absolute percentage error (MAPE) 0.494. LSTM model for Cheonan-si have RMSE 0.015, MAPE 0.668.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.195-203
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• 2014

The aim of this study was to investigate the effects of phonation types ([+/- aspirated], [+/- fortis]) on aerodynamic measures with Korean bilabial stops. Sixty-three healthy young adults (30 males, 33 females) participated to evaluate the VOEF (Voicing Efficiency) tasks with bilabial stop consonants /$p^h$/, /p/, /p'/ using Phonatory Aerodynamic System (PAS) Model 6600 (Kay PENTAX Corp, Lincoln Park, NJ). All VOEF measures were significantly influenced by phonation types except RANP(pitch range)(p <.01). For sound pressure, maximum SPL, mean SPL, and Mean SPL during Voicing have been shown to be significantly greatest in fortis stop /p'/ than aspirated /$p^h$/ and lenis stop /p/ (p<.001). On the other hand, mean pitch after lenis stop was significantly lower than after aspirated and fortis stops (p<.001). Peak expiratory airflow, Target airflow, and FVC (Expiratory volume) were significantly lowest in fortis stop /p'/ which might be associated with higher aerodynamic resistance while peak air pressure and mean peak air pressure during closure were significantly lower in lenis stop /p/. Additionally, AEFF (Aerodynamic efficiency) was significantly higher in fortis stop /p'/ than lenis stop /p/ as well as aspirated stop /$p^h$/ (p<.001). Thus, sound pressure, airflow parameters, and aerodynamic resistance made crucial roles in distinguishing fortis /p'/ from lenis stop /p/ and aspirated. Additionally, pitch and subglottal air pressure parameters were important aerodynamic characteristics in distinguishing lenis /p/ from fortis /p'/ and aspirated /$p^h$/. Therefore, accurate aspirated /p/ stop consonant should be elicited when collecting the airflow, intraoral pressure related data with patients with voice disorders in order to enhance the reliability and relevance or validity of aerodynamic measures using PAS.

• Women's Health Nursing
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• v.8 no.2
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• pp.151-164
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• 2002

PURPOSE: Estrogen replacement therapy is indicated for the relief of hot flushes and urogenital atrophy, the prevention of osteoporosis and the reduction in risk of cardiovascular disease. The present study assessed by blood pressure, heart rate variability, and climacteric symptoms in menopausal women before treatment and at 1 month during estrogen replacement therapy. METHODS: The study sample consisted of 16 healthy menopausal women (range 49 to 59 years, mean : 53.4 years) attending menopausal clinics for the complaint of climateric symptoms at S. hospital in Chunchoen. They were all non-smokers and no patient had symptoms or evidence of cardiovascular disease. They took estrogen replacement therapy (conjugated estrogen 0.625 mg with or without medroxy progesteron 2.5mg) for 1 month. Blood pressure, heart rate variability(heart period and vagal tone) through ECG, and climacteric symptom were measured in all subjects before treatment and at 1 month during treatment. Climacteric symptom questionnaire which was developed by Neugarten et al.(1963) was modified with 20 items of question(Cronbach's alpha = 88 -.89). The data was collected from Sept. 1. 2000 to July. 30. 2001. RESULTS: There was no significant difference in mean systolic and diastolic pressure between the baseline and at 1 month during treatment. The mean heart period and vagal tone were slightly increased, but difference of mean heart period and vagal tone were not statistically significant between the baseline and at 1 month during treatment. The score of climacteric symptoms decreased significantly from the baseline after treatment. CONCLUSIONS: Even though, this study did not show that estrogen replacement therapy led decrease of blood pressure and increase heart rate variability, climacteric symptoms reduced much in all subjects after taking drugs. These results suggest that there is need to repeat study with long term period.

• Journal of Preventive Medicine and Public Health
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• v.32 no.3
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• pp.395-399
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• 1999

Backgroud: Excess abdominal fat, expressed as an increased ratio of waist to hip circumferences (WHR), is independently associated with higher levels of blood pressure. Although a WHR greater than 1.0 in men has been shown to predict complications from obesity, the WHR has not been evaluated in all ethnic groups. Methods: In order to ascertain the association between WHR and classification of blood pressure and to investigate the critical value of WHR as a predictive factor of hypertension in Korean middle-aged men, we compared the mean of WHRs according to the classification of blood pressure in Seoul Cohort participants. Results: Through a surrey of direct measurement of waist and hip girth, 452 subjects were recruited from the cohort. The mean of WHR was 0.88 and its standard deviation was 0.04. The mean of WHRs was higher in the systolic blood pressure group (above 140 mmHg), diastolic blood pressure group (above 90 mmHg), and hypertension group than in the systolic blood pressure group (below 140 mmHg), diastolic blood pressure group (below 90 mmHg), and normotensive group, respectively. And WHR of above 0.89 was associated with hypertension (z-value =6.66). Conclusion: It is necessary for Korean males with WHR greater than 0.89 to recommend the primary prevention and early defection of hypertension.

• Journal of Sensor Science and Technology
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• v.17 no.2
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• pp.87-94
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• 2008

Blood pressure (BP), one of the most important vital signs, is used to identify an emergency state and reflects the blood flow characteristics of the cardiovascular system. The conventional noninvasive method of measuring BP is inconvenient because patients must wear a cuff on their arm and the measurement process takes time. This paper proposes an algorithm for estimating the BP using the pulse transit time (PTT) of the photoplethysmography (PPG) and pressure pulse from finger at the same time as a more convenient way to measure the BP. After recording the electrocardiogram (ECG), measuring the pressure pulse, and performing PPG, we calculated the PTT from the acquired signals. Then, we used a multiple regression analysis to measure the systolic and diastolic BP indirectly. Comparing the BP measured indirectly using the proposed algorithm and the real BP measured with a sphygmomanometer, the systolic pressure had a mean error of ${\pm}3.240$ mmHg and a standard deviation of 2.530 mmHg, while the diastolic pressure had a satisfactory result, i.e., a mean error of ${\pm}1.807$ mmHg and a standard deviation of 1.396 mmHg. These results are more superior than existing method estimating blood pressure using the one PTT and satisfy the ANSI/AAMI regulations for certifying a sphygmomanometer i.e., the measurement error should be within a mean error of ${\pm}5$ mmHg and a standard deviation of 8 mmHg. These results suggest the possibility of applying our method to a portable, long-term BP monitoring system.

• Journal of environmental and Sanitary engineering
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• v.22 no.1 s.63
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• pp.67-74
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• 2007

The purpose of this study is to provide the necessarily basic data of the ideal growth of the students by investigating the effect of the student's stress due to the parent's achievement pressure. The sample of this study are In students consisting of 51 boys and 49 girls in the 3rd grade classes of "J" middle school located in Siheung city, Kyungki-do. The observed materials are used to investigate the parent's achievement pressure and the level of stress. Based on the observed data, the frequency, correlation, and t-test have been gained. The results are summarized as follows : 1. The perception of the parent's achievement pressure is shown more by the boy's achievement pressure($44.2{\pm}9.9$) than the girl's achievement pressure($39.939{\pm}11.089$), among the high level students. 2. The perception of the parent's achievement pressure is shown more the high($43.0{\pm}10.7$) and middle($42.9{\pm}11.8$) level students than the low($39.7{\pm}8.00$) level students. 3. The stress of male students was high in the Solving Problem stress factor with by the mean of $15.1{\pm}3.7$, and the stress of female students was high in the Self-Control stress factor with the mean of $13.3{\pm}3.9$. 4. The stress of high, middle, low level student was high in the Solution of Matter stress factor with the mean of $14.2{\pm}3.9$. 5. The results were the main cause of the stress than the parent's achievement pressure.

• The Journal of Korean Physical Therapy
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• v.22 no.3
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• pp.17-21
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• 2010

Purpose: This study was designed to investigate possibilities for quantitative analysis using the electromyography and sonography. For better understanding, we evaluated the correlation between the pressure pain threshold and sonography, spontaneous electrical activity in trigger points located in the upper trapezius muscle. Methods: Thirty three active subjects volunteered to participate in this study (n=33). They had a palpable taut band, exquisite spot tenderness of a nodule in a taut band, spontaneous pain, referred pain, jump sign, local twitch response, and a painful limit to full stretch range of motion. We measured Pressure pain threshold, density, white area index, root mean square, and reaction. Pearson’s correlation coefficient was calculated to estimate the relationship between the pressure pain threshold and other variables including density, white area index, root mean square, and reaction time. Results: There were significant correlations between pressure pain threshold and density (r=-0.75, p<0.01), and between pressure pain threshold and white area index (r=-0.74, p<0.01). A significant correlations between pressure pain threshold and root mean square (r=-0.59, p<0.01). The significant correlation was found between pressure pain threshold and reaction time (r=-0.64, p<0.01). Conclusion: These should indicate whether quantitative analysis can be done using the characteristics of electromyography and sonography.