• 대한전기학회논문지
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• 제38권12호
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• pp.1022-1032
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• 1989

King Sejong's Striking Clepsydra was an elaborate timekeeping and annunciating system incorporating biological automata capable of annunciating hours, intervals and night-watches based on Shou-shih calindrical systems automatically. In this paper the author has studied the original manuscripts on the Striking Clepsydra [Sejong sillock, 65: 1a-3b ff` 16th year, 7th month(1434)] from the technical point of view undertaking a close analysis of this monumental clock and aiming to our modern understanding of the full degree of delicate mechanisms and sophisticated controls built into the night-watch and division announcing clockwork(jackwork). Based on the input/output model, timekeeping, ball-rack, ball-relay, and audible time-indicating mechanisms were synthesized reconstructing night-watch annunciating systems. It revealed that the night-watch and division announcing processes were entirely renewed automatically. Historical and philological data concerning the improvements of the proposed model were discussed.

• 한국통신학회논문지
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• 제35권2B호
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• pp.215-224
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• 2010

컨테이너 보안장치(CSD)는 컨테이너의 도어를 통한 침입을 감시하는 장치이며, IEEE 802.15.4의 비컨 모드에서 RFD로 동작한다. 그러나 비컨 모드에서는 CSD 리더가 없어도 주기적으로 리더의 신호를 탐지하게 되므로 배터리 소모가 크다. CSD는 목적지에 도착할 때까지 이상없이 동작해야 하므로 배터리 소모를 줄이고, 위험 발생 시 CSD 리더에게 능동적으로 메시지를 전달해야 한다. 본 논문에서는 미국 DHS의 CSD 규격에 부합하는 저전력 CSD를 제안한다. 제안하는 CSD는 전력 소모를 최소화한 하드웨어 디자인과 저전력 동작기법인 불침번 기법, 저전력 센싱 기능을 통해 배터리 소모를 줄인다. 또한 위험 상황 발생 시 리더에게 능동적으로 경고 메시지를 전달한다. 성능 평가 결과 제안한 CSD는 불침번 기법을 통해 배터리 소모를 70% 이상 줄이고, 저전력 센싱 기능을 통해 불필요한 센싱을 80% 이상 감소시키며, 직접적인 통신 거리 밖에 있는 리더에게 94%가 넘는 확률로 메시지를 전달할 수 있음을 보였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.697-701
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• 1996

King Sejong's Striking water-clock which brought in use on the first of July in 1434 was mainly composed of timekeeping and time announcing parts signalling twelve double-hours, and five night-watches and night-watch-divisions automatically by means of ball-operating jackworks. The clock was arranged with dual timekeeping system, the one for a full day(twelve double-hours) and the other for five night-watches achieving twelve double-hours and one-hundred interval horary systems. The vessels were arrayed in inflow-type water-clock, a large reservoir on the highest story, a constant-level tank for supplying water to the measuring vessel evenly in the middle, and the lowest tank to receive water from the above constant-level tank. An indicator-rod on the float was raised upwards depending on the water-level increase to show timing scales and also to release small bronze balls from the ball-rack mechanisms implanted on the measuring vessel to signal timing intervals.

• 대기
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• 제29권4호
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• pp.429-438
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• 2019

Organic carbon (OC) and elemental carbon (EC) in PM_2.5 were measured with Sunset Laboratory Model-5 Semi-Continuous OC/EC Field Analyzer by NIOSH/TOT method at Anmyeondo Global Atmosphere Watch (GAW) Regional Station (37°32'N, 127°19'E) in July and August, 2017. The mean values of OC and EC were 3.7 ㎍ m^-3 and 0.7 ㎍ m^-3, respectively. During the study period, the concentrations of reactive gases and aerosol compositions were evidently lower than those of other seasons. It is mostly due to meteorological setting of the northeast Asia, where the influence of continental outflow is at its minimum during this season under southwesterly wind. While the diurnal variation of OC and EC were not clear, the concentrations of O₃, CO, NOx, EC, and OC were evidently enhanced under easterly wind at night from 20:00 to 8:00. However, the high concentration of EC was observed concurrently with CO and NOx under northerly wind during 20:00~24:00. It indicates the influence of thermal power plant and industrial facilities, which was recognized as a major emission source during KORUS-AQ campaign. The diurnal variations of pollutants clearly showed the influence of land-sea breeze, in which OC showed good correlation between EC and O₃ in seabreeze. It is estimated to be the recirculation of pollutants in land-sea breeze cycle. This study suggests that in general, Anmyeondo station serves well as a background monitoring station. However, the variation in meteorological condition is so dynamic that it is primary factor to determine the concentrations of secondary species as well as primary pollutants at Anmyeondo station.

• 환경위생공학
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• 제11권1호
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• pp.77-82
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• 1996

Environmental issues are getting imrx>rtant and the polluted environment is now c considered as one of the serious social problems which we have to face. As a result, most people hate an night soil-treating establishment to be built near their village. This paper is intended to reveal the present situation of Sanitary Environment Bureau in Iksan City and its treatment of night soil. The conclusions are as follows 1. The mean quantity of treated night soil per day was approximately 126kl In 1995, and the treated quantity per month was largest in the months from May to August, but smallest in January and February. The quantity of the largest month doubled the one of the smallest, and it is considered to be because the microorganisms are more active in the warm season than in the cold season, being a a ble to process more night soil. 2. The after-treatment sewage water is regarded as being in an optimalcondition because the examination of the water discharged from the establishment revealed the result of BOD 16.67mg/l and SS 14.78mg/l in 1995. 3. The expense for treating human waste was ￦19,582 in Iksan Sanitary Environment Bureau and it was considerably lower than the average expense through the nation, i.e. ￦22,000-25,000. But the cost should be expanded for keeping outworn equipments from the old age. 4. It is desirable for the Bureau to open the establishment so that any adult or student can come into it and watch all the treating processes. It will help the citizens understand the need for the establishment in spite of its nasty and ugly impression. Other cities or countries have to follow this model and try to provide their citizens with a cleaner environment by investing more fund technology for it.

• 수면정신생리
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• 제12권1호
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• pp.27-31
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• 2005

목 적：동일한 피험자에 동시 착용된 두 기종의 활동기록기에서 얻어진 수면 관련 변수들을 서로 비교하고 이를 수면다원검사 결과와 비교하여 이들 두 기종의 활동기록기에서 얻어지는 수면변수를 상호 교환하여 사용할 수 있는 지를 평가하고자 하였다. 방 법：초기 평가 시 내외과적 질환, 정신과적 질환 및 수면 장애가 발견되지 않은 자원자 14명(남：여=5：9, 연령 $28{\pm}4.6$세)을 대상으로 하였다. 서울대학교병원 수면검사실에서 두 가지 종류의 활동기록기를 동시에 착용한 상태에서 수면다원검사를 시행하였고, 이들 세 기기에서 산출된 수면 변수들을 각각 비교하였다. 결 과：$ActiWatch^{(R)}$와 $SleepWatch^{(R)}$의 수면 변수를 수면 다원검사 결과와 각각 비교한 결과, $ActiWatch^{(R)}$와 $SleepWatch^{(R)}$ 모두 총수면 시간을 과대평가(overestimate)하는 경향을 보였으며, $SleepWatch^{(R)}$는 입면 잠복기를 과소평가(underestimate)하는 경향을 보였다. 세 기기를 통해 측정된 각 수면변수 비교 결과, 수면효율은 유의한 차이를 보이지 않았으며, $SleepWatch^{(R)}$의 입면 잠복기를 제외한 모든 수면 변수에서 선형적인 관련성을 보였다. 두 활동기록기에서 나온 수면 변수들 사이에는 유의한 차이가 발견되지 않았으며, 이들 사이에도 유의한 선형적인 관계가 있었다. 결 론：두 기종의 활동기록기에서 얻어진 결과들 사이에 유의한 차이를 보이지 않아서, 두 기종들의 결과는 서로 교환해서 사용할 수 있을 것으로 판단한다. 일반적으로 활동기록기가 수면다원검사를 대체하기는 힘들 것으로 생각되지만, 입면잠복기를 제외한 나머지 수면변수가 선형적 관련성을 보이므로 수면다원검사 시행 후 간단하게 치료반응에 대한 추적 관찰을 해야 하는 경우에는 활동기록기가 사용될 수 있을 것으로 생각한다.

• 한국가정과교육학회지
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• 제13권2호
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• pp.101-111
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• 2001

The purpose of the study is to investigate the relationships between the BMI and food preference. eating behaviors. and nutrition knowledge score among the middle school male and female students. A total of 394 students from 4 different middle school in Seoul were participated in this study. The students were categorized into 3 groups by BMI : under-weight(〈20). ideal(20$\leq$BMI〈25). and overweight($\geq$25) groups. The data on food preference. eating behavior. and nutrition knowledge were collected by a questionnaire. All data were analyzed by means as frequency. percentage. mean and standard deviation. F-test. $\chi$$^2$-test. and correlation analysis. The results obtained are summarized as follows : 1. BMI average of the male students was 21.4 About 45% of the students were in ideal weight group. 40% were in under-weight group. and 15% were in overweight group according to BMI. 2. About 62% of the participants wanted to lose weight : 43% of the male students. and 82% of the female students. And 33% of the students wished to lose more than 7kg of body weight. 3. Preference score for animal protein foods was the highest in overweight group. On the other hand. preference score of vegetables was the highest in under-weight group. 4. All 3 BMI groups eat more foods on dinner compared to lunch or breakfast. Eating amount score of between-meal was highest(eat more) in under-weight group. and the lowest(eat less) in overweight group. But the percentage of students who eat snack at night was the highest in overweight group. 5. Among the eating behavior variables. eating frequency of snack at night and eating speed were significantly different among 3 groups. Overweight group eat snack at night less frequently and eating speed is faster than the other groups(p〈.05). 6. Nutrition knowledge score was the highest in overweight group. but the difference was insignificant. It is shown that about 40% of the participants belong to under-weight group. but 62% wished to lose weights. Parents and teachers should watch out the juvenile students'health. especially whether they try to lose weight or maintain unrealistically low weight.

• 한국항해항만학회지
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• 제43권6호
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• pp.377-383
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• 2019

항해 중인 함정은 늘 충돌 가능성이 존재하지만 충돌회피를 위한 명확한 기동지침은 없고 함교 당직사관의 직관적 판단에 의존하는 경향이 있다. 본 연구에서는 항해 중인 함정이 방위끌림이 없는 장애물을 조우하는 상황에서 함교 당직사관을 대상으로 언제 어떻게 충돌을 회피하는지 설문조사를 실시하였다. 설문 결과를 활용하여 방위끌림이 없는 장애물 조우 상황, 주·야간 충돌 회피 방법을 분석하였다. 조함이 까다로운 지역은 평택, 목포 순이었고, 주로 협수로 내에서 발생하였다. 빈도는 4시간 항해 시 평균 1회 정도로 나타났으며, 1:1 조우 상황보다 다수 선박 조우가 많았다. 충돌침로 확인 시 전자해도보다 육안 확인 결과를 더 신뢰하였고, 충돌회피 고려 요소로 최단 접근거리, 최단 접근시간을 우선시하였다. 피항의무선과 침로유지선의 충돌회피 기동상 특별한 차이는 없었지만 주·야간 시 최단 접근거리의 차이는 존재했다. 충돌회피 시 대부분의 항해사들은 변침·변속을 함께 사용하는 것을 선호하며 타각 10~15°, 변속 ±5knots, 변침침로는 타함 함미 정방향에서 함미 가중치를 두었다. 이러한 결과들은 승조원들에게 부임 함정의 충돌 회피 기준을 제공하는데 도움이 될 것이며 나아가 AI, 빅데이터 기반의 무인함정 충돌회피 알고리즘 개발에도 적용될 것이다.

• Bulletin of the Korean Chemical Society
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• 제35권4호
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• pp.1149-1153
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• 2014

Real-time monitoring of hourly atmospheric radon (Rn-222) concentration was performed throughout 2011 at Gosan station, Jeju Island, one of the least polluted regions in Korea, in order to characterize the background levels, and temporal variations on diurnal to seasonal time-scales. The annual mean radon concentration for 2011 was $2527{\pm}1356$ mBq $m^{-3}$, and the seasonal cycle was characterized by a broad winter maximum, and narrow summer minimum. Mean monthly radon concentrations, in descending order of magnitude, were Oct > Sep > Feb > Nov > Jan > Dec > Mar > Aug > Apr > Jun > May > Jul. The maximum monthly mean value (3595 mBq $m^{-3}$, October), exceeded the minimum value (1243 mBq $m^{-3}$, July), by almost a factor of three. Diurnal composite hourly concentrations increased throughout the night to reach their maximum (2956 mBq $m^{-3}$) at around 7 a.m., after which they decreased to their minimum value (2259 mBq $m^{-3}$) at around 3 p.m. Back trajectory analyses indicated that the highest radon events typically exhibited long-term continental fetch over Asia before arriving at Jeju. In contrast, low radon events were generally correlated with air mass fetch over the North Pacific Ocean. Radon concentrations typical of predominantly continental, and predominantly oceanic fetch, differed by a factor of 3.8.

• 대한지역사회영양학회지
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• 제29권2호
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• pp.156-170
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• 2024

Objectives: This study aimed to investigate the association between how often Korean adolescents watch Mukbang and Cookbang videos and their dietary habits. Methods: Data from the 18th Korea Youth Risk Behavior Survey conducted in 2022 was analyzed for this study. The study included 51,850 middle and high school students and assessed various aspects, including demographics, frequency of watching Mukbang and Cookbang videos per week, dietary habits, health behaviors, and mental health factors. Results: Nearly a third (29.3%) of Korean adolescents watched Mukbang and Cookbang videos one to four times a week, while 13.5% watched them more than five times weekly. Females, those with lower academic achievement, and those from lower socioeconomic backgrounds were significantly more likely to be frequent viewers (P < 0.001). Increased viewing frequency was associated with poorer dietary habits. Adolescents who watched more frequently were less likely to eat breakfast and consume fruits and milk, while their consumption of fast food, high-caffeine drinks, sugary drinks, and late-night snacks increased (P < 0.001). Higher viewing frequency correlated with increased feelings of stress, depression, and loneliness (P < 0.001). Logistic regression analysis confirmed these associations. More frequent viewers were significantly less likely to eat breakfast (odds ratio (OR), 0.63; 95% confidence interval (CI), 0.58-0.68), and more likely to consume fast food (OR, 1.85; 95% CI, 1.69-2.02), high-caffeine drinks (OR, 1.43; 95% CI, 1.30-1.56), sugary drinks (OR, 1.54; 95% CI, 1.41-1.67), and late-night snacks (OR, 1.37; 95% CI, 1.25-1.51). Conclusions: Our findings suggest that frequent exposure to Mukbang and Cookbang content is linked to unhealthy dietary habits in adolescents. Educational programs may be necessary to mitigate the potential for these videos to negatively influence dietary choices.