• 상하수도학회지
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• 제13권1호
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• pp.95-112
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• 1999

In this research, it is proposed that optimization method is introduced and applied to the design of pipeline system in multi-regional water supply project, which has been constructed to settle the regional unbalance problems of available water resources. For the purpose, interface programs are developed to integrate linear programming model and KYPIPE model which is used for optimization and hydraulic analysis, respectively. The developed program is applied to the pipeline system design of multi-regional water supply project. The optimal diameters from the application of linear programming technique are compared with those from conventional method that is time-consuming and tedious trail and error process. Since the conventional design largely depends upon the experience of designers and the results of general hydraulic analysis, it can not be reasonable and consistent. The application of linear programming technique can make it possible to design pipeline system optimally by using same design factors of general hydraulic models. The model can select commercial discrete pipe diameter as optimal size by using pipe length as decision variables. The developed model is applied to Pohang multi-regional water supply system design with two different objective functions, which are initial construction cost and annual cost including electric cost. As results, it is calculated that the initial construction cost of 1,449,740 thousand won is saved and annual cost of 128,951 thousand won is saved for a year within study year. Also, the optimal site of pump station is selected on 5th pipe, which is located between the diverging junction to Kangdong(2) province and the diverging junction to Cheonbuk province. It is explained that pump cost is less than pipe cost in this application case study due to little pump station scale. In the case of water supply with large pump capacity, it is reasonal that the increase of pipe size is more efficient instead the increase of pump station capacity to save annual cost.

• Journal of Electrical Engineering and Technology
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• 제9권1호
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• pp.170-177
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• 2014

This paper presents a new method of classification of the induction machine faults using Time Frequency Representation, Particle Swarm Optimization and artificial neural network. The essence of the feature extraction is to project from faulty machine to a low size signal time-frequency representation (TFR), which is deliberately designed for maximizing the separability between classes, a distinct TFR is designed for each class. The feature vectors size is optimized using Particle Swarm Optimization method (PSO). The classifier is designed using an artificial neural network. This method allows an accurate classification independently of load level. The introduction of the PSO in the classification procedure has given good results using the reduced size of the feature vectors obtained by the optimization process. These results are validated on a 5.5-kW induction motor test bench.

• 한국농공학회논문집
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• 제64권3호
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• pp.9-24
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• 2022

Currently, a vast amount of hydrologic data is accumulated in real-time through automatic water level measuring instruments in agricultural reservoirs. At the same time, false and missing data points are also increasing. The applicability and reliability of quality control of hydrological data must be secured for efficient agricultural water management through calculation of water supply and disaster management. Considering the characteristics of irregularities in hydrological data caused by irrigation water usage and rainfall pattern, the Korea Rural Community Corporation is currently applying the Hampel filter as a water level data quality management method. This method uses window size as a key parameter, and if window size is large, distortion of data may occur and if window size is small, many outliers are not removed which reduces the reliability of the corrected data. Thus, selection of the optimal window size for individual reservoir is required. To ensure reliability, we compared and analyzed the RMSE (Root Mean Square Error) and NSE (Nash-Sutcliffe model efficiency coefficient) of the corrected data and the daily water level of the RIMS (Rural Infrastructure Management System) data, and the automatic outlier detection standards used by the Ministry of Environment. To select the optimal window size, we used the classification performance evaluation index of the error matrix and the rainfall data of the irrigation period, showing the optimal values at 3 h. The efficient reservoir automatic calibration technique can reduce manpower and time required for manual calibration, and is expected to improve the reliability of water level data and the value of water resources.

• Design & Manufacturing
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• 제14권4호
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• pp.1-10
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• 2020

The seal plays a role in preventing oil leakage when the lip and the rotating shaft come into contact with the fluid and air pressure. Recently, micro dimples or micro pockets are processed and used on the lubrication surfaces of thrust bearings, mechanical bearings, and piston rings. Compared to a smooth surface, micro dimples reduce friction and increase the life of parts. This paper analyzed various kinds of micro dimple shapes on the sealing surface, i.e. circle, rectangle, triangle, and trapezoid. For this purpose, Introduced the design of experiments to work out a micro dimple configuration, unlikely to be damaged from cracks and low in contact stress. As a result, the triangular dimple showed the best results. Optimal factors were dimple size 0.15 mm, dimple depth 0.0383 mm, dimple density 40%, and the maximum equivalent stress was 9.1455 MPa, and the maximum contact pressure was 9.6612 MPa. This paper analyzed the optimal shape of dimples by finite element analysis. As a research project, experiments and comparative analysis of micro dimple shapes are needed.

• Nuclear Engineering and Technology
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• 제40권3호
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• pp.175-182
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• 2008

The results of process development for the blending of waste salt from the electrorefining of spent fuel with zeolite-A are presented. This blending is a key step in the ceramic waste process being used for treatment of EBR-II spent fuel and is accomplished using a high-temperature v-blender. A labscale system was used with non-radioactive surrogate salts to determine optimal particle size distributions and time at temperature. An engineering-scale system was then installed in the Hot Fuel Examination Facility hot cell and used to demonstrate blending of actual electrorefiner salt with zeolite. In those tests, it was shown that the results are still favorable with actinide-loaded salt and that batch size of this v-blender could be increased to a level consistent with efficient production operations for EBR-II spent fuel treatment. One technical challenge that remains for this technology is to mitigate the problem of material retention in the v-blender due to formation of caked patches of salt/zeolite on the inner v-blender walls.

• 보건행정학회지
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• 제3권1호
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• pp.146-168
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• 1993

The study was conducted to project supply and demand of the nurses till year 2010 based on analysis of supply and demand of nurses up to year 1991. Results of the study will provide invaluable information for nurses manpower planning as well as overall health manpower planning for the 21th century. It is projected that nurses will be oversupplied based on the current prductivity which is undesirable situation if the quality of care is considered, and undersupplied based on the the medical law as well as optimal productivity. Thus, it is desirable to increase active supply of nurses. One of the ways of increasing active supply would be increasing the size of training and education. But, considering low employment rate of nurses which is about 59% better way of solving problems related to nurses shortage would be improvement in nurses' employment rate. According to simulation study done as part of this study, if nurses' employment rate goes up to 80%, there is no need for increasing the size of training to meet the demand at the level of medical law.

• 한국전자통신학회논문지
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• 제9권10호
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• pp.1153-1159
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• 2014

본 논문은 항만 개발에서 일부분의 주민참여가 아닌 대부분의 주민들이 참여가 가능한 ICT(Information Communication Technology)과 소셜 네트워크 기술을 적용하여 동해시의 묵호항 재개발 사업 친수 시설 규모 산정방안에 대한 새로운 방법을 제시한다. 이를 위해 항만 재개발 과정에서 효과적인 주민참여를 위한 방법으로 기존의 단순한 설문조사 방식과 더불어 다양한 SNS(Social Network System)을 적용하여 주민들의 의견 최대화한 도시 마케팅 방안을 분석한다. 또한 이를 위해서 주민 참여에 대한 비율을 최적 선정을 수행하고 최적 건설비 산정과 도시 마케팅 방안을 제시한다.

• Korean Journal of Radiology
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• 제19권6호
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• pp.1179-1186
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• 2018

Objective: The purposes of this study were to evaluate size-specific dose estimate (SSDE) of low-dose CT (LDCT) in the Korean Lung Cancer Screening (K-LUCAS) project and to determine whether CT protocols from Western countries are appropriate for lung cancer screening in Korea. Materials and Methods: For participants (n = 256, four institutions) of K-LUCAS pilot study, volume CT dose index ($CTDI_{vol}$) using a 32-cm diameter reference phantom was compared with SSDE, which was recalculated from $CTDI_{vol}$ using size-dependent conversion factor (f-size) based on the body size, as described in the American Association of Physicists in Medicine Report 204. This comparison was subsequently assessed by body mass index (BMI) levels (underweight/normal vs. overweight/obese), and automatic exposure control (AEC) adaptation (yes/no). Results: Size-specific dose estimate was higher than $CTDI_{vol}$ ($2.22{\pm}0.75mGy$ vs. $1.67{\pm}0.60mGy$, p < 0.001), since the f-size was larger than 1.0 for all participants. The ratio of SSDE to $CTDI_{vol}$ was higher in lower BMI groups; 1.26, 1.37, 1.43, and 1.53 in the obese (n = 103), overweight (n = 70), normal (n = 75), and underweight (n = 4), respectively. The ratio of SSDE to $CTDI_{vol}$ was greater in standard-sized participants than in large-sized participants independent of AEC adaptation; with AEC, SSDE/$CTDI_{vol}$ in large- vs. standard-sized participants: $1.30{\pm}0.08$ vs. $1.44{\pm}0.08$ (p < 0.001) and without AEC, $1.32{\pm}0.08$ vs. $1.42{\pm}0.06$ (p < 0.001). Conclusion: Volume CT dose index based on a reference phantom underestimates radiation exposure of LDCT in standard-sized Korean participants. The optimal radiation dose limit needs to be verified for standard-sized Korean participants.

• 한국의류학회지
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• 제31권11호
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• pp.1530-1541
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• 2007

The purpose of this study is to establish a standard sizing system for Taekwondo uniforms. The sample utilized in the study consisted of 5,679 male and female subjects, obtained from Size Korea Project. Twenty three measurements were identified and selected as critical in the design and construction of Taekwondo uniforms. The results were as follows: First, it was determined that all brands used "height" as a key dimension of size designation. Two of brands added "chest girth" or "numeric numbers" to designate size in addition to "height". For example: 1) height/chest girth, 2) height/numeric number. The size pitches of all current Taekwondo uniforms in the market were 10cm of height for all brands. Second, the study showed male measurements were larger and longer than females, establishing that independent sizing specifications by sexes are needed. Third, in case of Taekwondo shirts, height and chest girth were selected as control dimensions. In case of pants, height and waist girth were selected as control dimensions. For selecting optimal sizing pitch, 2 different pitches of chest girth and waist girth(4cm pitch by KS and 8cm pitch by researchers) were compared, while height pitch was fixed at 10cm. Fourth, based on the analysis of the measurements(coverages and coverage efficiency rates), it was determined that 8cm pitches of chest and waist girth were efficient in both upper and lower Taekwondo uniforms. Fifth, subjects distribution counts and percentages were shown after analyzing coverage efficiency rates. Separate results are noted for the upper and lower Taekwondo uniforms. As previously mentioned, height pitches were 10cm and chest and waist pitches were 8cm. Finally, as a result of this research, key and referable measurements relevant to making Taekwondo uniforms were identified for male and female uniform. In case of Taekwondo shirts, 18 sizes were established for men, 16 sizes for women. Twenty five sizes for men and 20 sizes for women were presented in size tables for pants.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.384-389
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• 2000

A artificial neural network model was developed to analyze and forecast the flow fluctuation at small streams in the Balan watershed. Backpropagation neural networks were found to perform very well in forecasting daily streamflows. In order to deal with slow convergence and an appropriate structure, two algorithms were proposed for speeding up the convergence of the backpropagation method, and the Bayesian Information Criterion(BIC) was proposed for obtaining the optimal number of hidden nodes. From simulations using daily flows at the HS#3 watershed of the Balan Watershed Project, which is 412,5 ㏊ in size and relatively steep in landscape, it was found that those algorithms perform satisfactorily.