• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.320-325
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• 2003

Acoustic-Pressure Response of diluted hydrogen-air diffusion flames is investigated numerically by adopting a fully unsteady analysis of flame structures. In the low-pressure regime, the amplification index remains low and constant at low frequencies. As acoustic frequency increases, finite-rate chemistry is enhanced through a nonlinear accumulation of heat release rate, leading to a high amplification index. Finally, the flame responses decrease at high frequency due to the response lag of the transport zone. For a medium-pressure operation and low-frequency excitation, the amplification index is low and constant. It then decreases at moderate frequencies. As frequency increases further, the amplification index increases appreciably due to an intense accumulation effect.

• 한국수자원학회논문집
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• 제45권4호
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• pp.393-407
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• 2012

본 연구에서는 과거에서부터 기록된 우리나라 65개의 관측소들을 대상으로 강수량 데이터를사용하여 강수빈도와 극한 지표들을 산출해 냄으로써, 지표에 따라 지역별 분포를 살펴보고 시공간적인 증 감율에 대한 결과를 제시하였다. 그 결과를 시계열로 도시함으로 쉽게 파악할 수 있지만경향이 뚜렷하게 나타나지 않는 경우에는 통계적 방법인 Mann-Kendall 경향성 분석을 실시하여 이에 대해 파악하였다. 더불어 FARD를 이용하여 100년과 200년의 빈도확률강수량을 산정하고 이를 비교하였다. 강우특성을 크게 Amount, Extreme, Frequency로 분류하고 각각의 지수를 강우량 지수(Rainfall Index for Amount), 강우극치 지수(Rainfall Index for Extremes), 강우빈도 지수(Rainfall Index for Frequency)로 정의하고 RIA, RIE, RIF를 산술평균하여 홍수에 대한 종합적인 강우 위험도를 나타내는 평균 강우지수(Average Rainfall Index, ARI)를 산정하였다. 그 결과 과거에 비해 최근 10년간 강우량의 정량적인 평가 특성은 양적으로 22.3%, 극치사상 발생측면은 26.2%, 빈도측면은 5.1% 증가하였음을 확인 할 수 있었다. 본연구의 결과는 최근 우리나라 기후변화 경향을 구체적으로 제시하고 있으므로 기후변화 대비 적응 연구의 기초 자료로 활용될 수 있다.

• 환경영향평가
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• 제15권3호
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• pp.207-215
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• 2006

The purpose of this paper is to analyze the spatial distribution and change of the frequency of Yellow Sand days and to examine their relationship with atmospheric circular characteristics at the surroundings of the Korean peninsula. Yellow Sand days data are used by intensity, Siberian High Index and monthly mean temperature of the Northern Hemisphere. In the Middle-western region, the occurrence frequency of Yellow Sand days was higher during the study period (1973-2004). Also, the occurrence frequency of Yellow Sand days increased to latter half 16 years compared with the first half 16 years, and be clearer in Middlewest regions. Yellow Sand days frequency increased, and the trend was distinct in the Jungbu region during the study period. Increasing trend of Yellow Sand days frequency was significant for the recent 22 years. Yellow Sand days had a negative relationship with Siberian High Index in February and March. Therefore, Siberian High Index became weaker in the spring, and possibility for the occurrence of Yellow Sand days was generating larger. Yellow Sand days had a positive relationship in monthly mean temperature of the Northern Hemisphere. Especially, the case of the strong Yellow Sand days is significant. Recently, global warming might be affecting the occurrence of strong Yellow Sand days.

• 한국안전학회지
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• 제20권3호
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• pp.64-70
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• 2005

In this literature, fault detection and classification of faulty induction motors are carried out through Z-index and frequency analysis. Above frequency analysis refer Fourier transformation and Wavelet transformation. Z-index is defined as the similar form of energy function, also the faulty and healthy conditions are classified through Z-index. For the detection and classification feature extraction for the fault detection of an induction motor is carried out using the information from stator current. Fourier and Wavelet transforms are applied to detect the characteristics under the healthy and various faulty conditions. We can obtain feature vectors from two transformations, and the results illustrate that the feature vectors are complementary each other.

• Journal of Nutrition and Health
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• 제33권6호
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• pp.675-683
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• 2000

The purpose of this study was to find out the prevalence of constipation nutrition knowledge on dietary fiber and frequency of dietary fiber foods intake of 3rd grade high school girls in Kangnung and Seoul. The total 412 questionnaires were analyzed. Defecation frequency was irregular in 47.6% of the students 21.6% had less than twice a week. Those who were in a hurry during defecation frequency was irregular in 47.6% of the students 21.6% had less than twice a week. Those who were in a hurry during defecation were 57.9% and those spent more than 10 min. for defecation were 21.8% More than half of the students(56.6%) answered to have constipation and 13.8% had taken laxative pills more than once during the last one month period. The nutrition knowledge score was relatively high 7.63 points out of possible 10. Dietary fiber intake scores measured by food frequency questionnaire were 3.78 for fruits 3.71 points out of possible 10. Dietary fiber food intake scores measured by food frequency questionnaire were 3.78 for fruits 3.71 for vegetables and 3.37 for seaweeds meaning taken once a week to 2-3 times per month. For the diagnosis of defecation difficulty a factor called "constipation index" was introduced which was composed of defecation frequency time spending for defecation easiness in defecation and feeling of residue in the intestine after defecation. The Cronbach a coefficient of constipation index was 71. Constipation index was significantly correlated with stress level(p<0.05) haste during defecation(p<.01) and defecation time(p<.01) The higher the stress level the more hurry during defecation and the later the defecation the higher the constipation index. The students who ate more often vegetables and seaweeds had lower constipation index(p<.05, p<.01)05, p<.01)

• 대한의용생체공학회:의공학회지
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• 제28권6호
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• pp.750-755
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• 2007

The linear SEF (Spectral Edge Frequency) parameter and spectrum analysis method can not reflect the non-linear of EEG. This method can not contribute to acquire real time analysis and obtain a high confidence in the clinic due to low discrimination. To solve the problems, the development of a new index is carried out using the bispectrum analyzing the EEG including the non-linear characteristic. At the bispectrum analysis of the 2 dimension, the most significant's power spectrum density peaks appeared much at the specific area in awake and anesthesia state. Because many peaks are showed at the specific area in the frequency coordinate, these points are used to create the new index. Range of the index is 0-100. At the anesthesia, the index is 20-50 and at the awake, the index is 90-60. New index can discriminate the awake and anesthesia state.

• 도시과학
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• 제11권2호
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• pp.9-17
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• 2022

The purpose of this study is to develop an index for evaluating the function of a new motorway using the travel distance frequency distribution (TLFD) calculated using the vehicle travel route big data, and to overcome the limitations of the evaluation through the existing traffic volume. The mobility evaluation index of motorways was developed by applying it to the TLFD data table in 2019. The smaller the value of the mobility evaluation index of the link is calculated, the more it is a link with mainly short-distance travel, and the higher the value of the mobility evaluation index, the more it means a link with mainly long-distance travel. The accessibility evaluation index was calculated through the result of the mobility evaluation index of all motorways developed, and all motorways were grouped into three groups using K-means clustering. Group A was found to exist inside a large city and consisted of motorways with many short-distance traffic, Group B was investigated as acting as an arterial between groups, and Group C was classified as a motorway consisting mainly of long-distance traffic connecting large cities and large cities. This study is significant in developing a new motorway function evaluation index that can overcome the limitations of motorway function evaluation through the existing traffic volume. It is expected that this study can be a reasonable comprehensive indicator in the operation and planning process of motorways.

• 대한물리의학회지
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• 제19권1호
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• pp.43-51
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• 2024

PURPOSE: Sarcopenic obesity (SO) is a clinical condition that combines sarcopenia and obesity. This study examined the frequency of SO in young Korean females between 20 and 29 years of age. METHODS: The study involved 1,000 participants. The height, weight, body mass index (BMI), waist circumference, skeletal muscle mass index, fasting glucose, triglyceride, total cholesterol levels, systolic and diastolic blood pressure, alcohol consumption, and smoking status were the research variables. The skeletal muscle mass index was calculated as appendicular skeletal muscle mass (ASM) divided by the BMI. The ASM was assessed using dual X-ray absorptiometry. Complex sampling analysis and multiple logistic regression were used for analysis. RESULTS: A .74(.30-1.80) frequency of SO was observed. The statistically significant risk factors in females were height, weight, BMI, waist circumference, skeletal muscle mass index, total cholesterol, systolic blood pressure, and diastolic blood pressure (p < .05). CONCLUSION: Young Korean adults with SO have a .74(.30-1.80) frequency of occurrence that is linked to specific risk factors. Hence, primary care clinicians and health care professionals should consider these factors when patients require a referral for early detection and treatment. Healthcare professionals and clinicians can identify potential SO patients by acknowledging these risk factors.

• 한국치위생학회지
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• 제13권2호
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• pp.261-269
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• 2013

Objectives : This research examined the Patient Hygiene Performance(PHP) index according to smoking and tooth brushing behavior, in order to analyze how they influence the oral hygiene. Methods : This research used PHP index and the structured questionnaire. The subjects were 203 men in their 20's who visited K university's dental hygiene department for oral prophylaxis from March to July of 2012. For data analysis SPSS WIN 12.0 was used. Results : 1. The average PHP index of all experimented subjects was 2.66, a very poor level. The PHP index according to general characteristics, smoking, drinking, and exercise showed statistical significance(p<0.05). 2. PHP index decreased with more frequencies and longer durations of toothbrushing(p<0.05). 3. The PHP index of smokers is higher than that of non-smokers. In the case of non-smokers, the frequency, method, and duration of tooth brushing had a statistical significance(p<0.05). 4. The PHP index of smokers who smoke less than or equal to ten cigarettes is 2.53 and smokers who smoked more than 10 cigarettes is 3.10. 5. The results of multiple regression analysis showed that smoking increased the PHP index, while the increase in tooth brushing frequency and the up and down tooth brushing method decreased the PHP index. All the coefficients were statistically significant (p<0.05). Conclusions : In order to increase Patient Hygiene Performance(PHP) index. there must be a decrease in smoking rate while people increase their tooth brushing frequency and use a proper tooth brushing method.

• 한국소음진동공학회논문집
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• 제22권11호
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• pp.1113-1120
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• 2012

This paper deals with the analysis of interior noise and low frequency noise characteristic for the Busan citizens to use public transport, Busan Metro Line 3. The interior noise evaluation index, articulation index(AI) is evaluated the lower value about average 22 % in a whole range, this is difficult to have a conversation. Also, noise criteria(NC) curve is partially evaluated as NC-65 below 2000 Hz, space type is evaluated as factories. Another of interior noise evaluation index, preferred speech interference level(PSIL) is evaluated the upper value about average 66 dB(A) in a whole range, this is evaluated to be interrupted. In the case of low frequency noise(20~200 Hz), the measurement of low frequency noise is assessed largely beyond noise criteria of ISO 226. The low frequency noise should be reduced because low frequency noise affects on psychological stress and displeasure although low frequency noise is not recognized by auditory sense. The low frequency noise criteria and guideline will be enacted from now on in Korea.