• Journal of Nutrition and Health
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• v.55 no.3
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• pp.359-375
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• 2022

Purpose: Adult Korean men belonging to the main economically active population are known to have long sedentary hours. This study was undertaken to determine the difference and relevance of sedentary hours on the nutrition, diet, and health status of adult men, and to suggest how to prevent health risk factors. Methods: Subjects (n = 1,068) were classified into 4 groups based on their sedentary hours, ranging from the first quartile (Q1) having the least hours spent sitting, to the fourth quartile (Q4) spending the longest hours. Results: Subjects belonging to Q4 had the lowest average age, the largest waist circumference, and the highest level of education. Among those engaged in economic activities, the ratio of white-collar workers was significantly higher in Q4. Accordingly, the rate of not doing high-intensity or moderate-intensity physical activity while working was also the highest in Q4. A significant difference was obtained in the drinking frequency between groups, but this was found to be associated with the average working hours rather than sedentary hours. The proportion of not doing aerobic exercise was higher with longer sitting hours. The highest diagnosis of diabetes (8.8%) was obtained in the Q4 group. Among the factors related to cardiovascular disease, only low density lipoprotein-cholesterol showed a significant difference, with Q4 being significantly higher than Q1. Considering energy and nutrient intake, vitamin B₁ and calcium intake were the lowest in the group with the longest sitting hours, as well as the least consumption of vitamin C than the recommended estimated average requirement. Conclusion: The results of this study suggest that the health and nutritional status of Korean adult men are affected by sedentary hours. This should be recognized as a health risk factor and guidelines need to be developed for sedentary lifestyle management.

• Korea journal of population studies
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• v.33 no.1
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• pp.27-49
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• 2010

The aim of this study was to get answers to following research questions: Who are the busy people in such a speedy society like Korea? How the daily schedules of busy people might look like? What is the priority of activity that appear in their schedules?, And what is the gender difference? The sample of study came form the 2004 Korean Time Diary Data which have been collected by Korean National Statistical Office. The sample consisted of 11,976 married men and women, whose age range from 25-54 (women 49.7% of the sample). Dependent variable was time pressure measured in one item question with 4-likert scale. Socio-demographic factors and the amount of time in work/family role and other relevant activities were considered as well as gender. The results of the study showed us that men perceived more time deficit compared to women. Especially, employed men were the most time poor group, followed by employed women, unemployed women and unemployed men. The results showed that, even though there were similarities in the impact of relevant factors, men's time pressure were tightly linked with their work role and social status, while women's time pressure were responsive to both their role as a mother and as a worker. Nowadays, Korean fathers appear to face new expectation that they need to be involved in family just like mothers do. However, men and women still seems to traverse through different time path, which may create both burden and conflict to either party. Policy implication and detailed suggestions were discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.300-300
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• 2010

Ceramic capacitor의 에너지내량을 향상시켜 제품의 신뢰성을 높이고자 RF Sputtering을 이용하여 외부전극을 형성하였다. 본 연구에서는 Target의 종류, 증착 시간 및 열처리 유/무에 따른 Ceramic capacitor의 전기적 특성 및 미세구조를 분석하여 최적조건을 확립하였으며, 최적 증착 조건으로 제작한 Ceramic capacitor의 에너지내량을 측정하였다. Target은 Ni target과 Cu target을 사용하였으며, Sputtering 시간은 10, 30, 60분으로 하였다. Sputtering 시간에 따른 Ceramic capacitor의 용량 특성과 손실은 큰 차이가 없었지만, Wire 연결시 Sputtering 시간에 따라 납땜성의 차이가 나타났으며, 증착 시간과 열처리 유/무에 따른 에너지내량의 변화를 확인하였다.

• Journal of Environmental Impact Assessment
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• v.20 no.5
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• pp.627-640
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• 2011

이 논문에서는 일사량과 일조시간에 관한 통상적인 선형관계식보다 정확한 비선형 관계식에 대한 적용검토를 수행한다. 일조시간을 이용한 일사량 추정에 이어서 Penman-Monteith 방정식을 이용하여 기준 증발산량을 추정하였다. 우리나라 20개 지점의 1997년부터 2006년까지의 일사량 및 일조시간 자료를 포함한 기상자료를 이용하여 선형 그리고 수정 비선형 Angstrom 방정식을 보정하고 기준 증발산량을 추정하였다. 일조시간과 일사량 사이의 선형과 비선형 관계식을 이용한 기준 증발산량의 상대비교를 수행하였다. 선형 및 비선형 관계식을 이용한 방법 모두 RMS 오차는 5.96, NSC(Nash-Sutcliffe Coefficient)는 0.95로 추정되었고, 그 차이는 매우 미미하였다. 그러나 상대적으로 일사량이 기준 증발산량에 크게 기여하는 하계에는 그 차이가 증가하기 때문에 보다 개선된 비선형 관계식을 이용하는 방법에 대한 엄밀한 검토가 필요하다.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.366-369
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• 2003

본 연구에서는 강건한 문맥의존 음향모델을 작성하기 위한 기초적인 연구로서 문맥환경과 상태수의 변화에 따른 음향모델의 성능을 고찰하고자 한다. 음성은 시간함수로 표현되며 음절, 단어, 연속음성을 발성할때 자음과 모음에 따라 발성시간에 차이가 있으며 음성인식의 최소 인식단위로 널리 사용되는 음소의 앞과 뒤에 오는 문맥환경에 따라 인식성능에 많은 차이를 보이고 있다. 따라서 본 연구에서는 시간의 변화(상태수의 변화)와 상태분할 과정에서 문맥환경의 변화를 고려하여 다양한 형태의 문맥의존 음향모델을 작성하였다. 모델학습은 음소결정트리 기반 SSS 알고리즘(Phonetic Decision Tree-based Successive State Splitting： PDT-555)을 이용하였다 PDT-SSS 알고리즘은 미지의 문맥정보를 해결하기 위해 문맥방향과 시간방향으로 목표 상태수에 도달할 때까지 상태분할을 수행하여 모델을 작성하는 방법이다. 본 연구에서 강건한 문맥의존 음향모델을 학습하기 위한 방법의 유효성을 확인하기 위해 국어공학센터의 452 단어를 대상으로 음소와 단어인식 실험을 수행하였다. 실험결과, 음성의 시간변이에 따른 모델의 상태수와 각 음소의 문맥환경에 따라 인식성능의 변화를 고찰할 수 있었다. 따라서 본 연구는 향후 음성인식 시스템의 강건한 문맥의존 음향모델을 작성하는데 유효할 것으로 기대된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1768-1772
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• 2007

본 연구에서는 국내 도시지역의 특성을 고려한 설계강우의 시간분포형에 따른 첨두유량의 변화를 규명하고자 Huff 및 Yen과 Chow의 시간분포방법을 이용하여 단시간 강우특성을 분석하였으며, 또한, 기왕의 연구인 건설교통부의 전기간 강우에 의한 시간분포와의 비교를 실시하고, 실제 도시지역에 적용하여 첨두유량의 변화를 분석하였다. 한다. 본 연구에서 선정한 대상지역은 서울, 부산과 대구지점이며, 강우자료는 1961년부터 2004년까지 44년간의 연속된 자료로서 기상청의 자기우량지 및 AWS자료를 이용하여 수집하였다. 첨두유량분석을 위한 대상유역으로는 서울특별시 일원의 성내와 반포배수구역과 부산광역시 일원의 동의대 시험유역, 경북 구미시 일원의 광평배수구역을 선정하였다. 본 연구의 수행으로 인해 얻어진 결과를 요약하면 다음과 같다. 첫째, Huff의 시간분포방법의 경우에는 단시간 강우자료의 지속기간에 따른 최대강우강도는 제1구간에서 발생할 확률이 가장 높게 나타났고, 제3구간에서 가장 낮게 발생하였으며, 기왕의 연구들과 차이가 발생하였다. 둘째, Yen과 Chow의 시간분포방법에서는 기왕의 연구와 본 연구의 결과에서 전반적으로 큰 차이가 발생하지 않았으며, 셋째, 첨두유량의 비교에서는 시간분포방법에 따라 변화가 발생함을 알 수 있었다.

• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.3185-3199
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• 2018

Middle- and old-aged driver's capability in recognition for driving scene elements was compared. Central and ambient stimuli were selected from natural driving scene and sensitivity, bias and reaction time were measured as dependent measures. The results are as follows. First, in general, older drivers showed lower sensitivity than middle-aged drivers. In particular, the older drivers' sensitivity was significantly lower for the ambient stimuli than central stimuli, whereas the middle-aged drivers showed no significant difference between the two types of stimuli. Second, the older drivers tended to show more lenient responses whereas the middle-aged drivers responded more conservatively. Third, the older drivers showed longer reaction time than the middle-aged drivers, in particular, in the responses of miss and correct rejection. This results suggested that the older drivers' retention for driving scene elements in their working memory may not be stable, which can be resulted in difficulties in rapid and accurate responses in a real life driving.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.5
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• pp.87-93
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• 2010

This paper presents a high resolution, wide input range 2-step time-to-digital converter used in digital PLL. TDC is used to compare the DPLL output frequency with reference frequency and should be implemented with high resolution to improve the phase noise of DPLL. The conventional TDC consists of delay line realized inverters, whose resolution is determined by delay time of inverter and transistor size, resulting in limited resolution. In this paper, 2-step TDC with phase-interpolation and Time Amplifier is proposed to meet the high resolution and wide input range by implement the delay time less than an inverter delay. The gain of Time Amplifier is improved by using the delay time difference between two inverters. It is implemented in $0.13{\mu}m$ CMOS process and the die area is $800{\mu}m{\times}850{\mu}m$ Current consumption is 12 mA at the supply voltage of 1.2 V. The resolution and input range of the proposed TDC are 0.357 ps and 200 ps, respectively.

• Journal of Animal Science and Technology
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• v.45 no.5
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• pp.857-864
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• 2003

In a trial involving 120 pigs, the effects of transport time on blood profile and meat quality in pigs were investigated. One group of 60 animals was subjected to 20 min and the others to 2 h transport time, and held in lairage for 1 h 30 min. There was not significantly different in the carcass weight, backfat thickness and carcass grade between groups. Cortisol and lactic dehydrogenase(LDH) concentrations were significantly(P〈0.05) higher in the group transported for 2 h compared with the group transported for 20 min. There was not significantly different(P〉0.05) in meat quality(pH$_1$, pH$_{u}$, drip loss, cooking loss, hardness, CIE L$^{*}$, a$^{*}$, b$^{*}$ and NPPC) and skin damage of pork carcass between groups. These results imply that the stress could be affected by transport time in transit without meat quality.

• Journal of Korean Society of Transportation
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• v.17 no.1
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• pp.113-129
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• 1999

It is widely recognized that the value of travel time (VOT) plays an important role both in choosing the transportation alternatives on an individual level, and in analyzing and evaluating transportation plans and other public policy makings on a collective level. There is, however, a great deal of difficulties to correctly estimate the VOT. In addition, although there are lots of methods to estimate the VOT so for, not many recommendations have been presented to reflect the localities associated with the VOT derivation in Korea. This study aims at deriving the VOT for different trip purposes and travel modes with their significances tested. To accomplish this purposes, a logit-based travel mode choice model based on revealed preference (RP) data has been formulated, calibrated using the discrete choice model of LIMDEP package for various trip purpose models. For each trip purpose and travel mode, the VOT has been calculated along with the significance testing of the derived VOTs. From the results given in this research, the VOTs for different purposes and modes are identified different, and they are statistically significant. The updated results here in this paper may be a yardstick in evaluating the transportation plans and policies by providing more detailed VOT information for different categories, especially in urban context.