• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1915-1919
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• 2007

하천관리 및 수공구조물의 설계 등을 위한 빈도별 홍수량 산정 시 이용되는 방법에는 Clark 단위도법, Snyder 단위도법, KICT 단위도법 등이 있다. 이 중 대표적인 합성단위도법인 Clark 단위도법은 실무에서 가장 많이 사용되는 방법으로 꼽을 수 있으나, Clark 단위도법 매개변수인 집중시간$(T_c)$과 저류상수(K)를 추정하는 것은 단순하지 않다. Clark 단위도법의 매개변수 추정은 계측 유역인 경우와 미계측 유역인 경우로 나눌 수 있는데 대부분의 경우 미계측 유역의 도달시간 및 저류상수를 추정하는 방법으로 홍수량을 산정하고 있는 실정이다. 본 연구에서는 감천유역을 대상유역으로 선정하였으며, 김천수위표 지점을 유출지점으로 선정하여 홍수량을 산정하였다. 호우사상은 김천수위국의 수위-유량 곡선식으로 유출량의 검정이 가능한 년도를 고려하여 1998${\sim}$2005년 사이의 호우사상 중 분석이 가능한 것으로 판단되는 부항2와 김천 강우관측소의 시강우 자료를 선정하였다. 선정된 호우사상은 1999년, 2002년, 2004년에 대한 총 6개의 시우량 자료로 WAMIS(국가수자원종합정보시스템)와 한강홍수통제소(www.hrfco.go.kr)의 자료실에서 제공하는 한국수문조사연보 자료를 이용하였다. 선정된 호우사상과 WMS모형을 이용하여 산정된 유역면적 및 강우관측소 별 Thiessen 가중계수를 이용하여 HEC-1모형의 최적화기법으로 Clark 단위도법의 집중시간$(T_c)$과 저류상수(K)를 산정하였으며, 계측유역의 매개변수를 산정하는 방법 중 저류방정식을 이용하는 방법을 이용하여 저류상수를 산정하여 비교하였다. 집중시간의 경우 1999년과 2002년에 비해 2004년의 결과값이 작게 산정되었으며, 저류상수의 경우 2004년의 결과값이 크게 산정되었다. 그러나, 저류방정식을 이용하여 저류상수를 결정하는 방법으로 산정한 저류상수는 비교적 일관성 있게 산정되었다.

• Journal of Service Research and Studies
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• v.4 no.2
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• pp.11-19
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• 2014

This study simulates cases with 20, 30, 40, 50, 60 and 100 students and 6 values as the parameter of mu. Using the simulation, an analysis was made of how the number of students that couldn't concentrate during class increased over the duration of time. When normalizing the difference in student number when the value of mu is constant, there was a decrease in percentage over time. It also showed a change in percentage when the value of time is fixed while the value of mu changes. Based on the result values, by estimating the mu value with the class atmosphere to predict the outcome and improve the lecture.

• Nuclear Engineering and Technology
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• v.10 no.2
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• pp.65-72
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• 1978

In this paper, it is attempted to investigate the phenomena of iodine stress corrosion cracking of Zircaloy-4 cladding failures in reactor through the results of similar out-of-pile test in iodine vapour. The main result of this experiment is a finding of the relation between the threshold stress which can lead to iodine stress corrosion cracking of Zircaloy-4 tube and the iodine concentration. The values of critical stress and the critical iodine concentration are also obtained. A model which relates failure time of Zircaley-4 tube to failure stress and iodine concentration is suggested as follows: log t$_{F}$ =5.5-(3/2)log$_{c}$-4log $\sigma$ where t$_{F}$ : failure time, minutes c: iodne concentration, mg/㎤ $\sigma$: stress, 10$^4$psi.

• Journal of Korea Water Resources Association
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• v.33 no.3
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• pp.315-330
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• 2000

The GIUH (Geomorphologic Instantaneous Unit Hydrograph) is to be applied to the ungauged or insufficiently gauged basins. For tIris purpose, an accurate estimation of the charactenstlc velocity is one very important part, but any proper method for this has not been developed yet. In case that we have enough rainfall and runoff clata, the estimation of the characteristic velocity may be an easy job, but it is out of the purpose of the GIUH. Remindmg that the purpose of GIUH the characterisbc veloclty should be estimated based on the geomorpholog1c analysis and also be snnple for easy apphcation. In tIris research analysis cmd application of the GruH was given to several sub-basins in Wi-stream river basin, Gono, Donggok and Hyoryung. After deriving the characteristic velocity througn a optimizatlOn process with real data, it is compared w1th several velOCIties der1ved from geOlnoI1Jhoclimatic instantaneous unit hydrograph theory and several other concentration time formulae. The estimated charactenstic velocities using Kerby, Kim, KInematic Wave, and Brasby- Williams formulae found to g1ve the appropriate results. Hmvever, as the Kerby, and the Kinematic Wave require user's decision of the IvIanning's n value, the K1m and the Braby-Williams seem to be more applicable and recommended as characteristic velocity formula.

• Journal of the Society of Naval Architects of Korea
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• v.39 no.3
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• pp.81-88
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• 2002

The root joint in the welding structures are apt to failure by the stress concentration which is occurred by the external force. Therefore, in the safety and reliability of structure, the complete penetration joint welding which are obtained by the groove welding with edge preparation is generally required. Nevertheless, fillet T-joint welding without edge preparation is often carried out in the fields to reduce working time and consumption of welding electrode, however, this process is likely to produce inadequate joint penetration such as root gap. In this paper, the focus of research is to investigate distribution of welding residual stresses in the plate(or flange) and web of T-joint weld, and especially in the near of root gap notch that is due to incomplete joint penetration. For the analysis, we have chosen model of T-joint weld in the cases of single and multi-pass welding with submerged arc welding and analyzed model by using finite element programs considering the heat conduction and thermal elasto-plastic theory.

• Journal of Oral Medicine and Pain
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• v.35 no.1
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• pp.1-18
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• 2010

I'd like to introduce a teaching method to improve learning efficiency. Most students are likely to ignore what they don't understand in the class of a course. The subject of Occlusion is essential to understanding prosthodontic and orthodontic subjects. It is necessary to let students know and review what they don't understand among parts of a chapter in the course of Occlusion. Therefore I look over the examination papers after every examination and input the problems that each student didn't solve into the C-language computer program and print the list of the contents that each student must study particularly. I give the lists to students and let them review and present their own weak parts of a chapter in the course of Occlusion in the next class. This teaching method leads to improvement in learning and is helpful to students as well as lecturers.

• Journal of the Korean Association of Geographic Information Studies
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• v.15 no.2
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• pp.139-149
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• 2012

Flooding caused by torrential rains and landslide causes the deaths of people and property damage as well as traffic congestion and isolation. Driver enters the dangerous area when driver doesn't recognize disaster information on the road and the damage is spread over time. In this paper, we will develop a smart phone application to collect dangerous disaster area information and a system based on C/S to manage the data received from the smart phone application. This system can analyze dangerous disaster areas using the data received from the smart phone application and the spatial database analyzed dangerous disaster areas is displayed in the smart phone application using a map server. We think that the suggested system provides more efficient information to user.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1078-1087
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• 2014

In the conventional centralized mobility management schemes, it can lead to single points of failure, occurrence of a bottleneck, since all data and control are concentrated on the mobility anchor which is located in home network. In the current research of distributed mobility management, it is doing research into distributed mobility management which is supported by distributed mobility anchors. Such schemes do not consider a failure of the mobility anchor. However, it could be an issue under tactical environment since it occur non-service problem due to anchor movement, maintenance, failure, etc. In this paper, we proposed new DMM scheme named T-DMM(Tactical-Distributed Mobility Management) which can support handover even if mobility anchor breaks down. From the numerical analysis, we evaluate signaling cost and handover latency.

• Food Science of Animal Resources
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• v.24 no.3
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• pp.260-265
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• 2004

This study was carried out to investigate aroma patterns of Hanwoo (Korean cattle) beef using electronic nose during refrigerated storage, and to compare these results with chemical quality (pH, TBARS). The M. longissimus muscle from Hanwoo carcasses after 24 hrs postmortem was obtained and stored at 5${\pm}$1$^{\circ}C$ for 7 days. Sensitivity (dR/RO) values among electronic nose data were changed differently during refrigerated storage, and showed significant difference on the 7th day of storage (p<0.01). The dR/RO from SY/G, SY/AA, SY/Gh, SY/gCTl, SY/gCT decreased but those from SY/LG, T30/1, P10/1, P10/2, P40/1, T70/2, PA2 increased during storage for 7 days. Mapping these data using PCA (principal component analysis) showed that the 1st day data were present in the middle of the right side, the 3rd day data were present in bottom part of this area and the 7th day data spread out more widely on the left side. In case of DFA (discriminant factor analysis), the flock clustered round and located in different side clearly comparing with PCA plot. In analysis of correlation coefficients among electronic nose data and chemical quality data, there was significant correlation among sensor data (p<0.001). But pH and TBARS were not significantly correlated with electronic nose data. Consequently, PCA and DFA plot by electronic nose data showed difference during refrigerated storage and there were significant correlations among sensors. Therefore it will be possible to detect separate aroma patterns of Hanwoo beef using electronic nose.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.6
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• pp.1027-1034
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• 2011

In order to provide the basic information on the agricultural environment in Daegwallyeong Highland, the characters of weather, water, and soil quality were investigated. The meteorological characteristics was monitored by automatic weather system (AWS) at 17 sites. The quality of water for samples were collected monthly at 24 sites depending on landuse style. Soil samples were collected from a forest, grassland, and the major vegetable cultivation areas such as potato, carrot, Chinese cabbage, onion, head lettuce, and welsh onion field. The weather showed the mountain climate, and the average yearly temperature is $6.4^{\circ}C$, the average temperature in January is $-7.6^{\circ}C$ and the average temperature in July is $19.1^{\circ}C$, and the change of temperature on the districts of Daegwallyeong is severe. The yearly record of precipitation shows 1717.2 mm. The water quality of crop field was worse than forest or grassland in Daewallyeong highland. In 2005, annual T-N, T-P, SS distribution of Chinese cabbage field showed 7.4~11.3, 0.061~0.1, and $3.0{\sim}53.0mg\;L^{-1}$. The potato field showed 3.1~7.2, 0.019~0.056 and $0.5{\sim}3.0mg\;L^{-1}$, respectively. Being compared of water quality between potato field and chinese cabbage field, it showed that the water quality of Chinese cabbage field was worse than potato field. On farming, the soil of crop cultivation showed pH 5.6 to 6.8, $18.0{\sim}42.4g\;kg^{-1}$ of OM, $316{\sim}658mg\;kg^{-1}$ of Avail. $P_2O_5$. The content of cations showed $0.41{\sim}0.88cmol_c\;kg^{-1}$ of Exch. K, $3.73{\sim}7.07cmol_c\;kg^{-1}$ of Exch. Ca and $1.17{\sim}1.90cmol_c\;kg^{-1}$ of Exch. Mg.