• The KIPS Transactions:PartC
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• v.15C no.3
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• pp.173-190
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• 2008

The purposes of this study is development of information security evaluation model for governments to analyze domestic and foreign existing models. Recent domestic information security certification systems have several problems, because shortage of organic connectivity each other. Therefore we analysis on domestic and foreign existing models, specify security requirements, evaluation basis and other facts of models, optimize these facts for governments, and develop new model for domestic governments.

• International Journal of Highway Engineering
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• v.8 no.3 s.29
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• pp.63-76
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• 2006

For a private toll road project, deciding optimal toll is an important element of economic analysis for the project and a challengeable work. In this study, the optimal toll of a private toll bridge, Geoga Bridge which connects Geoje Island of Gyeongnam Province and Gaduk Island of Busan was estimated using Stated Preference (SP) data. The SP data were collected by interviewing the passenger car drivers travelling on the National Road 14. They are latent users of the bridge. A fuzzy approximate reasoning model to estimate the optimal toll was built using the SP data. For the input variable of the model, the saved travel time and toll level were employed and the diversion rate to the bridge was employed for the output variable. The diversion rates for each toll level and saved travel time were estimated and the toll level which had maximized the toll revenue was decided as optimal toll. The optimal toll was tested by comparing with the average pay rate of passenger car drivers. Since the optimal toll for passenger cars at one hour saving, the 6,250 won is about 50 % of the average pay rate of passenger car divers, the toll was evaluated not to be high. The technique employed in this study may be used for the estimation of the optimal tolls for other kinds of vehicles.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.1016-1023
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• 1996

The effect of dietary calcium levels, 50%, 100%, and 200% of requirement, on iron utilization was evaluated in 30 Sprague-Dawley female rats by use of balance study for 3 weeks. In the results of this study, there were no significant difference in feed intake, body weight gain, hemoglobin level, hematocrit, calcium and iron levels in serum and tissues across the groups supplemented different calcium levels. Calcium content in kidney of high-calcium group was significantly higher than that of other groups. Urinary and fecal calcium excretions increased as the level of dietary calcium was increased. With increasing levels of dietary calcium, daily calcium retention was accelerated, but daily calcium retention rate was diminished. Iron intake was significantly higher in adequate-calcium group than that in low-calcium or high-calcium group. Urinary and fecal iron excretions were significantly lower in low-calcium group than those in adequate-calcium or high-calcium group. Apparent retention and retention rate estimated by intake, urinary and fecal excretions of iron were significantly lower in high-calcium group t]lan those in low-calcium or adequate-calcium group. These results suggest that taking dietary calcium supplements reduce the absorption of dietary iron.

• Proceedings of the Korean Reliability Society Conference
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• 2000.11a
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• pp.321-328
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• 2000

본 연구는 새로운 장비체계 도입 시 초기 일정기간 동안 장비의 목표가용도 유지를 위해 필요한 동시조달수리부속(Concurrent Spare Parts)와 적정소요 산출에 관한 해법을 제시한다. 새로운 장비체계 도입 시 함께 보급되는 예비수리부속은 장비체계 운용에 중요한 역할을 한다. 따라서 장비체계가 주어진 임무를 수행하는 동시에 정상상태를 유지하기 위한 적정수준의 예비부속 확보가 필요하며 최소의 비용으로 장비의 가동률을 극대화 할 수 있도록 하여야 한다. 본 연구에서는 부품의 고장특성 및 수리능력을 고려한 고장분포함수를 바탕으로 각 부속별 중요도를 만족시키는 초기 수리부속 소요 결정모형과 해 산정기법을 제시하며 가용예산 제약에 따른 소요조정을 통해 최적의 예비부속 재고수준을 결정한다.

• Journal of the Korea Society for Simulation
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• v.21 no.3
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• pp.25-33
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• 2012

Ptak & Smith published ORLICKY'S Material Requirement Planning Third Edition in 2011 to correspond the rapidly changed market demand by improving the original MRP based on Theory of Constraints(TOC) replenishment inventory management. This study is to develop the simulation model to decide the proper target inventory level for TOC replenishment inventory management using system dynamics Vensim software. This study shows that the proper target replenishment level is how much significant to manage the inventory by the random sample data simulation. This simulation model will be extended to compare the results of the TOC replenishment inventory management planning with the results of the old MRP planning by the enterprise actual inventory data.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.121-131
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• 2009

This study will estimate the fair return on private participants' investments on BTO type PPI (Private Public Infrastructure) projects using the data from past BTO projects in Korea. In the past, the real returns of $6%\sim9%$ were provided to private participants. The results of this study show that those returns were too high compared with the estimated fair returns, especially for projects with the minimum revenue guarantee (MRG) by the government. Moreover, the excess portion of the return over the fair return becomes even larger when there is a demand forecast bias. In reality, most of the BTO projects have far lower actual revenues than the initial forecasted revenue in concession agreements. This phenomenon implies that BTO projects have a tendency of overly forecasting revenues. If so, the value of the minimum revenue guarantee becomes larger, and therefore, the fair return to private participants should decrease. It is hoped that this study helps future BTO projects' concession agreements between the government and private participants to become more fair from the perspectives of risk and return profiles.

• 한국ITS학회:학술대회논문집
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• 2010.05a
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• pp.120-125
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• 2010

• Proceedings of the Korea Contents Association Conference
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• 2015.05a
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• pp.127-128
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• 2015

아동안전지킴이 근무자의 만족도를 조사한 결과 응답자의 약 70퍼센트가 만족 이상으로 응답하였고 회귀분석결과 순찰노선의 적정성 인식(=.182, p<.001)과 활동비 적정성 인식(=.163, p<.001)이 만족도에 영향을 미치는 것으로 분석되었다.

• Journal of Aquaculture
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• v.11 no.1
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• pp.1-10
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• 1998

A feeding trial was conducted to investigate optimum dietary protein and lipid levels in diets for parrot fish (Oplegnathus fasciatus). Three groups of 25 fish averaging 7.0g were fed each of the experimental diets containing 30, 40, 50 or 60% crude protein (CP) with 8 or 16% crude lipid level ($4{\times}2$factorial desing) for 8 weeks. Weight gain and feed efficiency increased significantly (P<0.05) with dietary protein level up to 50% CP when diets contained 16% lipid level, and increased with dietary protein level up 60% CP when diets contained 8% lipid level (P<0.05). The broken-like model showed that an optimum dietary protein level was 46% when the diet contained 16% dietary lipid. Fish fed diets containing 16% lipid level showed significantly (P<0.05) higher weight gain, feed efficiency and protein efficiency ratio than did fish fed diets containing 8% lipid level when diets contained 40 or 50% dietary protein (P<0.05).

• Journal of Korean Society of Transportation
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• v.29 no.1
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• pp.17-27
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• 2011

This paper investigates some critical errors influencing travel demand estimation in Korea Transportation Data Base (KTDB), and through this investigation reasonable traffic analysis zone (TAZ) size and internal trips ratio are analyzed. With varying zone size, the accuracy of travel demand estimation is studied and appropriate level of zone size in KTDB is also presented. For this purpose zonal structure consisting of location of zone centroid, number of centroid connecters has been constructed by social economic index, and then some descriptive statistical analyses such as F-test, coefficient of correlation are performed. From the results, this paper shows that the optimum levels of zone system were various according to the order and capacity of roads, and also shows that the smaller TAZ, the less error in this research. In conclusion, in order to improve accuracy of traffic demand estimation it is necessary to make zone size smaller.