• 한국지리정보학회지
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• 제21권3호
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• pp.119-126
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• 2018

본 연구는 현 기본수준면 기반의 수로측량 시스템과 타원체 기반의 수로측량 시스템을 분석하여 좀 더 일관성 있는 해저지형자료를 얻을 수 있는 방법에 대해 연구하였다. 이를 위해 타원체 기반의 수로측량을 동일한 측선 라인에 대하여 왕복 수행하였다. 그리고 해수면의 승강현상(조석 에너지 및 그 외 해양환경 에너지에 따른 해수면 변화)을 기본수준면 기반의 보정방법과 타원체 기반의 수심 보정방법으로 각각 처리하여 수심을 산출 하였다. 분석결과, 동일 구역(측선)의 수심단차현상이 기본수준면 기반의 산출물보다 타원체 기반의 산출물이 좀 더 향상된 것을 확인 할 수 있었다. 이러한 결과는 타원체 기반의 수로측량을 수행할 경우 측량구역의 해수면 변동을 실시간으로 반영함으로서 좀 더 일관성 있는 해저지형을 생성 할 수 있다고 사료된다.

• Nuclear Engineering and Technology
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• 제40권5호
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• pp.429-438
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• 2008

The objective of the present study is the depth and layout optimizations of a single layer, high level radioactive waste repository in a discontinuous rock mass with special joint set arrangements. A single layer repository model, considering variations in the repository depths, pitches, and tunnel spacings, is used to analyze the thermomechanical interaction behavior. It is assumed that the repository is constructed in saturated granite with joints; the PWR spent fuel in a disposal canister is installed in a deposition drift which is then sealed with compacted bentonite; and the backfill material is filled in the repository tunnel. The decay heat generated by the high level radioactive wastes governs the thermomechanical behavior of the near field rock mass of the repository. The temperature and displacement behavior of the repository is influenced more by the pitch variations than the tunnel spacing and repository depth. However, the stress behavior is influenced more by the repository depth variations than the pitch and tunnel spacing. For the final selection of the tunnel spacing, pitch, and repository depth, other aspects such as the nuclide migration through a groundwater flow path, construction costs, operation costs, and so on should be considered.

• 대한치과의사협회지
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• 제50권8호
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• pp.460-464
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• 2012

Periodontitis is the most prevalent noncontagious disease. Periodontal probing for measuring probing depth (PD) and clinical attachment level (CAL) has been an important diagnostic tool to determine the presence and severity of periodontal diseases. For probing reproducibility, adroit probe handling with constant force is required.

• 한국해양공학회지
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• 제8권1호
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• pp.62-70
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• 1994

In order to estimate the detection range of a active SONAR system, the SONAR equation is commonly used. In this paper, an algorithm to calculate detection range in active SONAR system as function of SONAR depth and target depth is presented. For given SONAR parameters and environment, the transmission loss and background level are found, signal excess is computed. Using log-normal distribution, signal excess is converted to detection probability at each range. Then, the detection range is obtained by integrating the detection probability as function of range for each depth. The proposed algorithm have been applied to the case of omni-directional source with center frequency 30Hz for summer and winter sound profiles. It is found that the optimal search depth is the source depth since the detection range increase at source depth where the signal excess is maximized.

• Asian-Australasian Journal of Animal Sciences
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• 제21권12호
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• pp.1785-1793
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• 2008

Fifty-four PIC barrows were used to evaluate the effects of lower dietary lysine content and energy level on carcass characteristics and meat quality in slaughter pigs. Pigs were allotted to one of three treatments by body weight with six replicate pens in each treatment. The dietary treatments for body weights of 20-50 kg, 50-80 kg and 80-90 kg were as follows, respectively: control diet (digestible energy 14.22 MJ/kg, lysine/DE 0.67 g/MJ, 0.53 g/MJ and 0.42 g/MJ); a low lysine group (digestible energy 14.22 MJ/kg, lysine/DE 0.49, 0.38 and 0.30 g/MJ); and a low lysine-low energy group or low nutrient group (digestible energy 13.11 MJ/kg, lysine/DE 0.49, 0.38 and 0.30 g/MJ). The daily weight gain, daily feed intake and feed efficiency were calculated in the overall growth period (nearly 12 weeks). Meanwhile, carcass characteristics and meat quality were evaluated at 60 and 90 kg body weight respectively. During the overall growth trial, lowering dietary lysine and nutrient level both decreased weight gain (p<0.05) and feed efficiency (p<0.01). At 60 kg body weight, decreasing dietary lysine and nutrient level noticeably decreased dressing percentage (p<0.01) and back fat depth at last rib of PIC pigs (p<0.01), but enhanced marbling scores (p<0.10), intramuscular fat content (p<0.10) and water loss rate (p<0.01) of the longissimus dorsi muscle. At 90 kg body weight, lean percentage (p<0.01) was evidently reduced by both lowering lysine content and nutrient level in the diet. However, the shoulder back fat depth (p<0.05) and marbling scores of the loin eye muscle (p<0.05) were increased; Lowering dietary nutrient level could improve back fat depth of 10th rib (p<0.01) and last rib (p<0.01), intramuscular fat content (p<0.10), redness (p<0.01) and water loss rate of the loin eye muscle (p<0.05), but decrease loin area (p<0.05). Finally, when comparing the 60 kg and 90 kg slaughter weights, it was found that the shoulder back fat depth (p<0.01, p<0.10), 6th-7th rib (p<0.01, p<0.01), 10th-rib (p<0.01, p<0.01) and last rib back fat depth (p<0.01, p<0.01) of the low lysine and low nutrient group were all obviously increased comparing with the control group. Taken together, the results showed that decreasing dietary lysine content and nutrient level increased intramuscular fat content and water loss rate of longissimus dorsi muscle; On the other hand, both lowering dietary lysine and nutrient level markedly compensated to increase back fat deposition in the later finishing period (body weight from 60 to 90 kg) in contrast to the control group.

• 한국구조물진단유지관리공학회 논문집
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• 제21권3호
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• pp.19-26
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• 2017

콘크리트는 다공성 건설재료이며, 매립된 철근의 부식은 내구성 및 안전성에 큰 영향을 미친다. 본 연구는 비파괴 검사인 반전위측정값과 생성된 부식량과의 상관성을 피복두께, 물-시멘트비를 고려하여 도출하는 것이다. 이를 위해, 3가지 수준의 물-시멘트비와 4가지 수준의 피복두께를 가진 시멘트 모르타르 시편이 제조되었으며, 3가지 수준의 촉진부식기간을 고려하여 부식량 및 반전위를 측정하였다. 습윤상태에서는 반전위가 크게 증가하였으며, 부식량과 촉진기간은 선형적인 관계를 가지고 있었다. 부식량이 증가할수록, 피복두께가 감소할수록, 물-시멘트비가 증가할수록 반전위는 증가하였다. 전체의 반전위 측정값을 부식량과 비교할 경우 0.67의 낮은 결정계수를 가지고 있었으나 부식량(촉진기간)을 고려하여 3가지 수준을 고려할 경우 0.90이상의 높은 결정계수를 가지고 있었다. 실내조건과 같이 온도가 일정하고 포화상태일 경우, 측정된 반전위는 부식량과 선형적인 상관성을 가지고 있었으며, 피복두께, 물-시멘트비, 철근직경, HCP의 측정범위를 알 수 있다면, 매립된 철근의 부식량을 예측할 수 있다고 판단된다.

• 인지과학
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• 제18권2호
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• pp.193-221
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• 2007

본 연구에서는 모바일 화면에서의 효율적인 메뉴구조를 탐색해보고자 하였다. 실험 1에서는 유목의 명확성(명확, 불명확)과 깊이수준(2,3,5층), 아이템의 수(32, 64, 128개)에 따른 탐색 과제 수행 시간과 오류수의 차이를 알아보았다. 그 결과 유목이 명확할수록, 깊이수준이 낮을수록 그리고 제시된 아이템의 수가 적을수록 과제 수행 시간이 짧았고 오류를 적게 보였다. 또한 유목이 명확한 조건에서는 깊이수준과 아이템의 수에 따른 과제 수행 시간과 오류 수에 차이가 없었으나, 유목이 불명확한 조건에서는 깊이가 깊은 조건과 아이템의 수가 많은 조건에서 과제수행 시간이 더 많이 소요되었고, 더 많은 오류를 보였다. 실험 2에서는 깊이가 5수준인 메뉴 구조에서 유목의 명확성(명확, 불명확), 아이템의 수(32, 64, 128개), 공간단서 (색, 창, 숫자단서)에 따라 과제 수행시간과 오류수의 차이가 있는지 알아보았다. 그 결과 유목이 명확할수록, 아이템의 수가 적을수록 과제수행시간이 더 적게 걸렸고 더 적은 오류를 보였다. 특히 유목이 불명확한 조건에서는 아이템의 수가 많을수록 더 좋지 않은 수행을 보여 실험 1과 동일한 결과를 보여 주었다. 또한 실험 2의 결과, 그림이나 숫자를 통해 공간단서를 제공하는 것이 탐색 과정에서 발생하는 오류를 줄이는데 도움이 될 수 있음을 보여 주었다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.2
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• pp.173-177
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• 2006

From the viewpoint of coastal hydrodynamics, one of the most important effects of global warming is a sea-level rise in coastal areas. In the present study, impacts on port facilities against sea-level rise were investigated. The sea-level rise causes the increase of the water depth, and it generates variations on the wave height, buoyancy, tidal system and nearshore current system and so on. The increase of water depth gives rise to the decrease of crown height of the structure and it causes increase of wave overtopping quantity. It may flood the port zone and its facilities, and may decrease harbor tranquility. It also leads to difficulties on navigation, mooring and loading/unloading at the port. Increase in water depth also causes increase of wave height in surf zone. This high wave makes structures unstable and may cause them to collapse during storm. In addition, increase in buoyant force due to sea-level rise also makes the gravity type structures unstable. Consequently, theses variations due to sea-level rise will cause functional deterioration of port facilities. In order to protect port facilities from the functional deterioration, reinforcement plan is required such as raising the crown height and increase in block weight and so on. Hence proper estimation method for the protection cost is necessary in order to protect port facilities efficiently. Moreover response strategies and integrated coastal zone management plan is required to maintain the function of port facilities. A simple estimation of cost for breakwaters in Korea was performed in the present study.

• Safety and Health at Work
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• 제6권1호
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• pp.18-24
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• 2015

Background: In 2006, three farmers died at the bottom of an agricultural shallow well where the atmosphere contained only 6% oxygen. This study aimed to document the variability of levels of oxygen and selected hazardous gases in the atmosphere of wells, and to identify ambient conditions associated with the low-oxygen situation. Methods: A cross-sectional survey, conducted in June 2007 and July 2007, measured the levels of oxygen, carbon monoxide, hydrogen sulfide, and explosive gas (percentage of lower explosive limit) at different depths of the atmosphere inside 253 wells in Kamphaengphet and Phitsanulok provinces. Ambient conditions and well use by farmers were recorded. Carbon dioxide was measured in a subset of wells. Variables independently associated with low-oxygen condition (<19.5%) were identified using multivariate logistic regression. Results: One in five agricultural shallow wells had a low-oxygen status, with oxygen concentration decreasing with increasing depth within the well. The deepest-depth oxygen reading ranged from 0.0% to 20.9%. Low levels of other hazardous gases were detected in a small number of wells. The low-oxygen status was independently associated with the depth of the atmosphere column to the water surface [odds ratio (OR) = 13.5 for 8-11 m vs. <6 m], depth of water (OR = 0.17 for 3-<8 m vs. 0-1 m), well cover (OR = 3.95), time elapsed since the last rainfall (OR = 7.44 for >2 days vs. <1 day), and location of well in sandy soil (OR = 3.72). Among 11 wells tested, carbon dioxide was detected in high concentration (>25,000 ppm) in seven wells with a low oxygen level. Conclusion: Oxygen concentrations in the wells vary widely even within a small area and decrease with increasing depth.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.233-236
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• 2006

This study presents a technique to quantitatively measure the corrosion level of a reinforcing bar using the infrared thermography system. The temperature-distribution of the concrete surface is monitored and the temperature change of the reinforcing bar is analysed in terms of corrosion level and concrete cover depth. The experimental results indicate that temperature increase of the reinforcing bar is significant when the corrosion level is high, which implies that the quantity of heat is strongly dependent on corrosion level. Also, as the concrete cover depth of the specimen and the atmosphere temperature increase, the temperature variation becomes small.