• Journal of Korean Society of Transportation
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• v.29 no.2
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• pp.91-100
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• 2011

Hub network design for freight transportation is a decision process that determines hub locations together with freight transportation routes among shippers so as to ultimately minimize total logistics cost. This study presents the optimal location of hubs by strict hub network design policy with single allocation, which overcomes the limitation of Kim et al. (2008) that does not allow direct transportation among shippers. The greedy-interchange algorithm is employed for hub location decision process, and EMME/2 is adopted for the route searching process. Application of the processes to the nationwide highway network shows that the best hub locations in order are Seoul metropolitan, GyeongNam, Chung-nam, Jeon-Nam, Gyeong-Buk, Chung-Buk, and the locations are concentrated on the Seoul-Busan corridor. The strict hubnetwork design policy with single allocation increases the transportation distance but decreases the transportation cost by passing through the hubs instead of direct transportation. The reduction in total transportation cost can be achieved as the number of hubs increases, but the amount of the reduction gradually decreases because the cost reduction from the decrease in detour transportation distance between non-hubs and hubs becomes less than the discount reduction from dispersion of inter-hubs transportation volumes.

• Progress in Medical Physics
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• v.16 no.4
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• pp.161-165
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• 2005

The CT number corresponds to electron density and its influence on dose calculation was studied. Five kinds of CT scanners were used to obtain Images of electron density calibration phantom (Gammex RMI 467), Then the differences between CT numbers for each scanners were ${\pm}2\%$ In homogeneous medium and $9.5\%$ in high density medium. In order to Investigate the influence of CT number to dose calculation, patients' thoracic CT images were analyzed. The maximum dose difference was $0.48\%$ for each organ. It acquired the phantom Images inserted high density material in the water phantom. Comparing the doses calculated with CT Images from each CT scanner, the maximum dose difference was $2.1\%$ in 20 cm in depth. The exact density to CT number conversion according to CT scanner is required to minimize the uncertainty of dose depends on CT number Especially the each hospital with various CT scanners has to discriminate CT numbers for each CT scanner. Moreover a periodic quality assurance is required for reproducibility of CT number.

• The Journal of the Korea Contents Association
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• v.10 no.3
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• pp.250-257
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• 2010

In this study, three different devices, Norland, Osteocore and Lunar were used to compare and analyze the measurement error by each bone density measurement device by classifying the physical characteristics into age, height and weight, the subject of total 300 sampling 100 persons for each device. Categorizing Lumbar region and Femoral neck as normal (T-score$\geqq$-1.0), osteopenia (-1.0>T-score>-2.5) and osteoporosis (T-score$\leqq$-2.5), the findings were observed as follows. Norland device showed the least measurement error in age and height, while Lunar showed the least in weight among the devices. And, the result of comparing the bone density measurement error based on the lumbar region showed that all of Lunar, Norland and Osteocore have the least variation of measurement error in osteopenia and the result of comparing based on the femoral neck showed that all of Lunar, Norland and Osteocore have the least variation of measurement error in osteoporosis. For each variable, the measurement error was observed to be vary upon the device. To solve this, standardized common Phantom should be used to compare and converge the measured value of each company and cross-calibration would be necessary when replacing the software.

• Journal of Korean Society of Transportation
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• v.21 no.1
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• pp.53-63
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• 2003

The Origin-Destination(OD) matrix is very important in describing transport movements in a region. The OD matrix can be estimated using traffic counts on links in the transport network and other available information. This information on the travel is often contained in a target OD matrix and traffic counts in links. To estimate an OD matrix from traffic counts, they are the major input data which obviously affects the accuracy of the OD matrix estimated, Generally, the quality of an estimated OD matrix depends much on the reliability of the input data, and the number and locations of traffic counting points in the network. Any Process regarding the traffic counts such as the amount and their location has to be carefully studied. The objective of this study is to select of the optimal location of traffic counting points for the OD matrix estimation. The model was tested in nationwide network. The network consists of 224 zones, 3,125 nodes and 6,725 links except to inner city road links. The OD matrix applied for selection of traffic counting points was estimated to 3-constrained entropy maximizing model. The results of this study follow that : the selected alternative to the best optimal counting points of six alternatives is the alternative using common links of OD matrix and vehicle-km and traffic density(13.0% of 6,725 links), however the worst alternative is alternative of all available traffic counting points(44.9% of 6,725 links) in the network. Finally, it should be concluded that the accuracy of reproduced OD matrix using traffic counts related much to the number of traffic counting points and locations.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.12
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• pp.1765-1777
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• 2002

본 연구에서는 현재 국내의 서울시내에 거주하는 모터사이클을 타는 만20세 이상의 남성을 대상으로 모터사이클복에 대한 착용실태와 불만사항들을 조사하고 이를 연령별, 모터사이클 유형별로 비교 분석하여 착용감 및 안전성이 향상된 모터사이클복 개발을 위한 기초자료를 제시 하고자 하였다. 설문조사는 2002년 1월~3월까지 3개월간 총 400부를 배부한 후 회수하고, 이 중 262부를 분석자료로 사용하여 빈도 및 백분율, 평균 등의 기술 통계치를 얻어 전반적인 착용현황을 알아보고, 교차분석을 실시한 후 X$^2$-검증을 실시하여 연령별, 모터사이클 유형별, 운행경력 별로 통계적인 차이를 비교 분석하였다. 1. 모터사이클복의 착용실태 및 불만사항 전반에 관한 조사결과, 조사대상자는 20대~40대의 운행경력은 5년 이상인 전문 라이더들이 많았으며 모터사이클의 배기량은 400cc이상이 가장 높게 나타났고, 모터사이클 유형은 로드 바이크가 가장 높게 나타났고, 이용목적은 레져.취미용, 선호하는 모터사이클복 아이템별 소재는 원피스와 슬랙스의 경우에는 피혁소재가 쟈켓의 경우에는 텍스타일 소재가 높게 나타났다. 아이템별 소유는 쟈켓과 투피스가 높게 나타났고, 보호구가 필요하다고 생각되는 신체부위는 상의에서는 가슴과 팔꿈치, 하의에서는 무릎으로 나타났으며, 무릎보호대의 소유도가 가장 높게 나타났다. 모터사이클복 주된 착용목적은 '부상방지', 모터사이클복을 착용하지 않는 이유는 '움직이기가 불편해서' '가격이 비싸서' '여름철에 더워서'가 각각 높게 나타났다. 모터사이클복에 대한 불만족도에서 동작적합성과 사이즈에 대한 불만도가 높게 나타났고, 모터사이클복소재 및 내부 장착 보호장구의 경량화가 요구되었으며, 모터사이클 쟈켓의 치수부적합부위는 소매길이가 가장높게 나타났다. 2. 전체 응답자의 연령을 20대, 30대, 40대 이상으로 나누어 연령별 차이를 비교한 결과 각각의 문항에 대해서 모두 연령대별로 유의차가 인정되었다. 3. 모터사이클복 아이템별 선호소재 문항에서 원피스와 쟈켓에서 모터사이클 기종별 유의차가 나타났는데, 비즈니스 기종에 서는 텍스타일 소재를, 아메리칸크루져 기종에서는 피혁소재를 선호하였다. 로드바이크와 오프로드 기종에서는 원피스는 피혁소재를 선호하였고, 쟈켓은 텍스타일 소재를 선호하는 것으로 나타났다.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.185-194
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• 2008

When forecasting demand for a new road, a select link analysis is usually used to understand the OD pairs that send trips along paths that use the selected link (i.e., the new road). These OD pairs and their associated volumes are listed in a select link analysis. However, there is no research about other methods to obtain these results, so experts are almost always dependent on select link analysis results to obtain these results. The purpose of this study is to propose a model with a different approach from select link analysis to obtain the previously mentioned results. Time and spatial characteristics of networks are used in this new approach. Select link analysis results are used as a comparison index for the results by the proposed model. Also, two case studies (interzonal trips and intracity trips) are performed to validate the significance of the model. Consequently, a correlation coefficient between the results by the proposed model and the comparison index shows high significance: 0.82.

• Korean journal of applied entomology
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• v.60 no.4
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• pp.423-429
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• 2021

The ovipositional characteristics of the endangered species Prosopocoilus astacoides blanchardi was investigated for indoor mass-rearing. This insect required 3 weeks or more for mating after emergence when introduced at the 1:1 ratio of male to female. Among temperatures studied at 16, 20, 24, 28, and 32℃, the pre-ovipositional period of P. astacoides blanchardi was longest at 16℃ with an average of 109 days after emergence, while it was shortest at 32℃ with an average of 59.4 days. The number of eggs laid at 24℃ was highest with an average of 40.6 per female. The average lifespan of adults at 16℃ was 208.8 days for males and 263.9 days for females, while at 32℃ 96.1 days for males and 130.3 days for females. The number of laid eggs was dependent on insect rearing chamber size. The oviposition-trees did not significantly (P > 0.05) affect the number of laid eggs and ovipositional period. The results of this study could be used as rearing data for the restoration and mass propagation of the endangered species P. astacoides blanchardi.

• Korean Journal of Ecology and Environment
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• v.56 no.4
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• pp.406-413
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• 2023

Captive breeding and reintroduction are crucial strategies for conserving endangered species populations. However, fish raised in predator-free environments, show a lack of recognition of predationrelated stimuli such as chemical and visual signals. It is critical to recognize chemical signals from injured conspecifics, also known as alarm signals, and the order or shape of predators to indicate the spread of predation risk in the habitat. We conducted a laboratory experiment to determine and adjust the optimal exposure period to induce appropriate anti-predator behavior response to different types of stimuli (Chemical, Visual and Chemical+Visual) for the endangered species Microphysogobio rapidus. Our results demonstrate that predator avoidance behavior varies depending on the types of stimuli and the duration of predation risk exposure. First, the results showed captive-breed M. rapidus show lack of response against conspecific alarm signal (Chemical cue) before the predation risk exposure period and tend to increase response over predation risk exposure time. Second, response to predator (visual cue) tend to peak at 48 hours cumulative exposure, but show dramatic decrease after 72 hours cumulative exposure. Finally, response to the mixed cue (Chemical+visual) tend to peak prior to the predation risk exposure period and show reduced response during subsequent exposure periods. This experiment confirms the lack of responsiveness to conspecific alarm signals in captive-bred M. rapidus and the need for an optimal nature behavior enhancement program prior to release of endangered species. Furthermore, responsiveness to predator visual signal peak at 48 hours cumulative exposure, suggest an optimal predation risk exposure period of up to 48 hours.

• Aerospace Industry
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• v.47
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• pp.56-59
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• 1997

''''95년 10월 3일 일본 나고야 근교의 미쓰비시 중공업 고마끼 공장에서 차기 전투기 FX-2의 처녀 비행이 여러 관계기관 사람들이 주목하는 가운데 실시되어 40여분간 비행하고 가볍게 내려 앉았다. 이보다 약 2개월 앞서 일본 신관이 참석한 엄숙한 의식을 치르고 미쓰비시 중공업 고마끼 공장에서 치러진 출고식에 이은 경사였다.

• Proceedings of the Korean Society of Environment and Ecology Conference
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• 2010.10a
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• pp.227-229
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• 2010