• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1515-1524
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• 2008

In this study, railway accidents from constructing or maintaining works on/near operating line were reviewed during 2005-2007 years. Causes and hazards analysis of these accidents was performed to make an accident scenario for risk assessments. And the risk of worker casualty on/near operating line was quantitatively assessed. Also a constitution method of Risk Matrix for manage tolerable risk level was proposed.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.546-549
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• 2004

The T-50/A-50 Golden Eagle was developed for a supersonic trainer and light combat aircraft. At the design stage, vibration control plans were established and applied. For cockpit vibration, crew comfort vibration level was defined by the requirement of MIL-A-8892. It is found that the T-50/A-50 meets the requirement of cockpit vibration from the flight test data analysis. This paper contains the results of cockpit vibration analysis using the flight test data and the results of human vibration analysis lot the pilot inside aircraft. The human vibration level of pilot is increased as dynamic pressure is increased and at the specific high dynamic pressure, the ride comfort indicates 'a little uncomfortable'. Overall analysis results show that the vibration level of T-50/A-50 cockpit is tolerable and not critical for pilot's comfort.

• Nutrition Research and Practice
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• 제5권6호
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• pp.548-552
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• 2011

The purpose of this study was to estimate the daily manganese (Mn) intake of Korean children. This study was done using a three-day dietary intake survey of 257 Korean children (boys 123; girls 134). The Mn intake values were calculated based on a database that provides the Mn content of the frequently consumed Korean foods, alongside the food composition table provided by the Korean National Rural Living Science Institute. The average age, height, weight and body mass index of our subjects were 11.9 years, 155.4 cm, 48.9 kg and 20.2 kg/$m^2$ in boys and 11.9 years, 154.1 cm, 43.5 kg and 18.3 kg/$m^2$ in girls. The average daily energy intakes were 2,249.2 kcal in boys and 2,044.5 kcal in girls. Boys consumed significantly more Mn than girls, based on intake estimates of $4,585.3{\mu}g$ (117.6% of adequate intake) and $4,029.3{\mu}g$ (117.1% of adequate intake), respectively (P < 0.001). Boys had a Mn intake of $2,041.1{\mu}g$ per 1,000 kcal of energy consumption, whereas for girls this was at $1,983.9{\mu}g$ per 1,000 kcal. Neither group exceeded the tolerable upper intake level for Mn. The major food groups which contributed to Mn intake in our subjects were cereals (50.8%), vegetables (21.0%), seasonings (8.9%), and pulses (7.7%). Notably, boys derived a higher Mn intake through cereals and vegetable than did girls (P < 0.001, P < 0.05). The key food sources of Mn, in descending order, were rice, soybean curd, kimchi, black rice and cereals. We propose that the results of our study may be used as a basis for follow-up studies that examine the Mn intake of children.

• Journal of Nutrition and Health
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• 제39권7호
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• pp.692-698
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• 2006

The voluntary addition of vitamins and minerals to the appropriate foods may help reduce the risks associated with low intakes of these micronutrients, yet the potential of excessive intake, particularly for persons consuming very large amount of foods needs to be addressed. Using the Flynn's model to estimate the level of each vitamins and minerals that can be added safely to foods, maximum levels of fortification to conventional foods per 100 kcal portion were estimated. Critical factors in the Flynn's model included tolerable upper intake level (UL), each micronutrient intake at the $95^{th}$ percentile, the proportion of fortified foods in the diets of individuals, the proportion of foods to which micronutrients could be practically added, and a range of estimates for fractions of foods which might be actually fortified in each nutrient. Food vehicles included all foods except for fresh foods and alcoholic beverages, in general. With fortification of 50% of all potentially fortifiable foods, micrornutrients could be added safely to foods at levels per 100 kcal 1) > 100% Recommended Intake (RI) for vitamin $B_12$, 2) 1,200% RI for vitamin $B_1$ and niacin, 3) 1,000% $B_1$ for vitamins $B_2$ and $B_6$, 4) 400% RI for vitamin E, 5) 30% RI for calcium, 6) 20% RI for folic acid, iron and zinc, 7) 10% RI for manganese, 8) no fortification for magnesium, phosphorous and vitamin A, and 8) further consideration of vitamin D, copper and selenium due to insufficient evidence. Results of this study suggests a wide range of vitamins and minerals that can be added safely to foods in current diets of Koreans.

• 대한족부족관절학회지
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• 제12권2호
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• pp.185-188
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• 2008

Purpose: Zone I fractures of the fifth metatarsal bone can generally be treated by conservative methods while both surgical and conservative methods are used for zone II fractures. However, the clinical results of conservative treatment have been rarely reported. The purpose of this study is to report the clinical results of conservative treatment for zone I and II nondisplaced fractures. Materials and Methods: Between July 2007 and August 2008, consecutive thirty seven patients (38 fractures) with zone I and II fractures of the fifth metatarsal bone were treated with tolerable weight bearing and minimum duration of immobilization based on pain on weight bearing. We evaluated the duration of immobilization, time to clinical and radiographic union, and time to pre-injury activity level. Results: Clinical and radiological union were achieved in all patients without any complications including malunion or nonunion. The mean duration of immobilization was 28.7 days. The mean 33.1 days and 48.9 days were required for clinical union and radiographic union respectively, after the initial injury. The mean time to pre-injury activity level was 4.8 months. Conclusion: Our study shows that the acute nondisplaced zone I, II fracture of fifth metatarsal bone can be treated effectively using tolerable weight bearing and minimum duration of immobilization, which is based on the pain on weight bearing.

• 한국운동역학회지
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• 제26권1호
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• pp.93-99
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• 2016

Objective: The purpose of this study was to investigate the effect of transcutaneous electrical nerve stimulation (TENS) treatment on maximum voluntary force (MVF) production. Methods: Ten healthy, young subjects (5 males and 5 females) participated in the study. MVF was recorded after a fifteen minute session of TENS stimulation under two conditions: low frequency (4 Hz) at maximum tolerable level and high frequency (110 Hz) at maximum tolerable level. TENS was provided simultaneously via self-adhesive electrodes placed on the finger pads of the index, middle, ring and little fingers. MVF was also recorded in a baseline condition with no TENS treatment. Data were collected in three different sessions on three consecutive days at the sametime of the day. Results: Results from the study show that on an average, MVF increasesby 25% for the index, middle and little fingers for TENS treatment with 4 Hz frequency as compared to the baseline condition. However, the 110 Hz condition did not result in a significantly different MVF than the baseline condition during individual finger pressing tasks. In addition, while producing MVF with all the four finger stogether, MVF was 30% higher for the 4 Hz conditionin comparison to the baseline condition, and 15% higher for the 110 Hz condition in comparison to the baseline condition respectively. Conclusion: The results suggest that stimulation ofafferent fibers onthe glabrous skinwith TENS could have a net facilitatory effect on the maximum motoroutput.

• 한국통신학회논문지
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• 제32권1A호
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• pp.13-23
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• 2007

본 논문에서는 OFDMA(Orthogonal Frequency Division Multiple Access) 시스템에서 실시간 트래픽 전송을 위한 효율적 패킷 스케줄링 기법을 제안한다. 본 방식은 패킷의 시간 지연 구속을 우선 만족시키면서 데이터 전송률도 향상시키는 기법으로 TEDC(Throughput Enhancement Under Delay-Constraint)라 불리운다. 사용자별 트래픽 특성에 따른 허용 지연 시간(Tolerable Delay Time TDT)을 정의하여 다양한 시간 지연 요구 조건을 차별화 하여 관리함으로써 무선 자원의 사용 효율을 향상시킨다. 논문에서 제안하는 TEDC 방식은 두 단계로 이루어진다. 첫 번째 단계에서는, 실시간 서비스를 위해 요구되는 시간 지연 구속을 만족하기 위해 잔여 허용 시간이 남지 않은 긴급한 사용자들에게 우선적으로 무선자원을 할당한다. 두 번째 단계에서는 첫 번째 단계에서 할당하고 남은 잉여 무선 자원에 대해서 자원의 활용도를 최대화하여 전체 데이터 전송률(Throughput)을 향상시킨다. 제안된 TEDC 방식의 성능은 기존의 자원할당 방식인 Round robin, M-LWDF, EXP 방식과 패킷 손실률, 데이터 전송률, 채널 활용도 측면에서 비교, 분석된다. 시뮬레이션 결과, TEDC 방식이 패킷 손실률, 데이터 전송률, 채널 활용도 측면에서 다른 자원 할당 방식보다 모두 우수한 성능을 보였다.

• 한국안전학회지
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• 제30권6호
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• pp.164-173
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• 2015

There exists required safety integrity level (SIL) to assure safety in accordance with international standards for every electrical / electronics / control equipment or systems with safety related functions. The SIL is allocated from lowest level (level 0) to highest level (level 4). In order to guarantee certain safety level that is internationally acceptable, application of methodology for SIL allocation and demonstration based on related international standards is required. However, application standard differs from every industry in domestic or international for application on mythology for allocation and demonstration of SIL. Application or assessment is not easy since absence on clear criteria or common definition. This research studied not only fundamental concept of SIL required to guarantee safety in accordance with international standards for safety related equipment and system, but different types of methodologies for SIL allocation. Specifically, SIL allocation for Platform Screen Door system of railway is studied applying methodology of severity of accidents and risk graph among different methodologies for SIL allocation.

• Journal of the korean society of oceanography
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• 제32권2호
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• pp.75-84
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• 1997

Relation between the length scale and the wall proximity function in the Mellor-Yamada level 2.5 turbulence closure model has been investigated through various experiments using a range of wall proximity functions. The model performance has been evaluated quantitatively by comparing with laboratory data for wind-driven flow (Baines and Knapp, 1965) and for open-channel flows without and with adverse wind action (Tsuruya, 1985). Comparison shows that a symmetric wall proximity function used by Blumberg and Mellor(1987) gives rise to current profiles with better accuracy than asymmetric wall proximity functions considered. It is noted that in modelling homogeneous flows the length scale 1= 0.31${\|}$z${\|}$(1+z/h) can be used with tolerable accuracy.

• 한국물환경학회지
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• 제35권2호
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• pp.105-114
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• 2019

The objective of this study was to investigate the pollution assessment of organic matters, nutrients, and metals in sediment in major lakes (5 lakes and 17 sites) of Buk-han river using various sediment pollution assessment guidelines and indices. The concentrations of organic matters and nutrients were lower than class IV (Sediment pollution assessment guidelines of Korea) and Severe Effect Level (SEL, Sediment pollution assessment guidelines of Ontario). This results indicated that the lakes sediments were unpolluted and tolerable level for sediment dwelling organisms by organic matters and nutrients. However, several sites of Chuncheon and Soyang lakes were evaluated "heavily polluted" level by organic index (Org-index). The order of lakes by metals concentrations from the one with the highest concentration was Hwacheon, Chuncheon, Cheongpyeong, Uiam, Soyang. All lakes except Hwacheon were assessed unpolluted to marginally and tolerable level for sediment dwelling organisms by metals based on sediment pollution assessment guidelines (Korean and Ontario), indices of geoaccumulation ($I_{geo}$), pollution loading (PLI) and ecological risk (RI). In Lake Hwacheon, every investigated sites were polluted with metals, especially Hg, based on sediment pollution assessment guideline of Korea and indices ($I_{geo}$, PLI and RI). The dwelling organisms in sediment of Hwacheon Lake were likely to be severed by metals.