• Journal of KIISE:Computer Systems and Theory
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• v.27 no.7
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• pp.650-664
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• 2000

NOW(Network of Workstations) is considered as a platform for running parallel programs by many people. One of the fundamental problems that must be addressed to achieve good performance for parallel programs on NOW is the determination of efficient job scheduling policies. Currently most research on NOW assumes that all the workstations in the NOW have the same processing power. In this paper we consider a NOW in which workstations may have different computing power. We introduce 10 classes of space sharing-based scheduling policies that can be applied to the NOW with heterogeneous computing power. We compare the performance of these scheduling policies by using the simulator which accepts synthetically generated sequential and parallel workloads and generates the response time and waiting time of parallel jobs as performance indices of various scheduling strategies. Through the experiments the case when a parallel program is partitioned heterogeneously in proportion to the computing power of workstations is shown to have better performance than when a parallel program is partitioned into parallel processes of the same size. When the owner returns to the workstation which is executing a parallel process, the policy which just lowers the priority of the parallel process shows better performance than the one which migrates the parallel process to a new idle workstation. Among the policies which use heterogeneous partitioning and process priority lowering, the adaptive policy performed best across the wide range of inter-arrival time of parallel programs but when the load imbalance among parallel processes becomes very high, the modified adaptive policy performed better.

• Journal of the Korea Convergence Society
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• v.11 no.10
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• pp.19-24
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• 2020

Artificial intelligence technology, which is the core of the 4th industrial revolution, is making intelligent judgments through deep learning techniques and machine learning that it is impossible to predict if it is applied to stock prediction beyond human capabilities. In US fund management companies, artificial intelligence is replacing the role of stock market analyst, and research in this field is actively underway. In this study, we use BLSTM to reduce errors that occur in unidirectional prediction of the existing LSTM method, reduce errors in predictions by predicting in both directions, and macroscopic indicators that affect stock prices, namely, economic growth rate, economic indicators, interest rate, analyze the trade balance, exchange rate, and volume of currency. To help stock investment by accurately predicting the target price of stocks by analyzing the PBR, BPS, and ROE of individual stocks after analyzing macro-indicators, and by analyzing the purchase and sale quantities of foreigners, institutions, pension funds, etc., which have the most influence on stock prices.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.3
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• pp.531-538
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• 2024

While the importance of the water quality environment is being emphasized, the water quality index for improving the water quality of urban rivers in Gwangju Metropolitan City is an important factor affecting the aquatic ecosystem and requires accurate prediction. In this paper, the XGBoost and LightGBM machine learning algorithms were used to compare the performance of the water quality inspection items of the downstream Pyeongchon Bridge and upstream BanghakBr_Gwangjucheon1 water systems, which are important points of Gwangju Stream, as a result of statistical verification, three water quality indicators, Nitrogen(TN), Nitrate(NO3), and Ammonia amount(NH3) were predicted, and the performance of the predictive model was evaluated by using RMSE, a regression model evaluation index. As a result of comparing the performance after cross-validation by implementing individual models for each water system, the XGBoost model showed excellent predictive ability.

• Journal of the Korean Society of Radiology
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• v.7 no.6
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• pp.419-426
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• 2013

This study was performed in order to suggest the basic informations about the proper oral health babits for kindergarten children, through the investigation of the oral health survey and their oral haelth behaviors. 213 of kindergarten children age 6 were surveyed who has lived at Daegu city and the examined data were analysed by use of spss 18.0 ver.program. The children who had performed the toothbrushing for 3 or 4 times a day, were estimated as high level in voluntary under taking of toothbrushing. It revealed that the low of the caries experience rate in the group of the sabiects who performed toothbrushing at every after meals. On the other hands, both the caries experience index of children who had perfomed toothbrushing with the rolling method and the dental plague index of children who had performed the toothbrushing just the morning time of the oral examination day, wer reveealed as high scores, due to the lack of the abilities to perform the toothbrusing with the proper method. It was needed to educate children for practical performing the toothbrush as well as for traning it with the right way, in order to promote the oral health for kindergarten children.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.369-369
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• 2017

농업용저수지는 이수 목적으로 비홍수기 농업용수 공급을 위한 용수 확보를 주요 목적으로 하고 있다. 한편, 농업용저수지가 홍수조절능력 또한 지니고 있음이 다수의 연구를 통해 제기되고 있으며, 이에 치수 목적으로 홍수기 홍수피해 저감을 위한 치수 대책 또한 수립할 필요가 있다. 현재 우리나라 농업용저수지의 홍수기 운영은 제한수위 방식을 기준으로 하되 필요에 따라 예비방류를 허용하는 조합 형태를 취하고 있다. 이러한 운영 방식은 홍수기 이후 상시만수위로 복귀하지 못하면 해당 년도 잔여 비홍수기 혹은 다음 년도 영농 시작 시기의 농업용수 공급에 차질이 생길 수 있다는 문제점이 있다. 따라서 홍수기 농업용저수지의 운영은 홍수조절과 함께 상시만수 위로의 복귀를 동시에 고려하여 이루어질 필요가 있다. 가변 홍수기 제한수위 (Variable Restricted Water Level, VRWL) 방식은 홍수 발생빈도와 규모를 고려하여 단위기간별 (일별 혹은 순별) 제한수위를 차등 부여하는 방식으로, 한정된 저수공간의 효율적 재할당에 따라 이수와 치수의 효율을 증대시키는 방안이 될 수 있다. 따라서 본 연구에서는 농업용저수지를 대상으로 저수지 유입량 빈도해석을 수행하고 순별 가변 홍수기 제한수위를 산정한 후 가변 홍수기 제한수위 적용에 따른 홍수조절효과를 평가하고자 한다. 연구대상지는 전국 110개 둑높이기 농업용저수지 중 가능최대홍수량 대상저수지 (유역면적 2,500 ha 이상, 총 저수량 500만 톤 이상) 12개소로 선정하였고, 저수지별 기상자료와 지형자료를 구축하였다. 저수지 유입량 모의를 위하여 장기유출량 산정 모형인 TANK를 이용하였으며, 구축된 저수지 유입량 자료를 토대로 순별 유입량 빈도해석을 수행하고 홍수기 저수지 유입량의 이론적 확률분포형을 선정하였다. 선정된 확률분포형을 토대로 초과확률 10%에 따른 순별 저수지 수위로서 가변 홍수기 제한수위를 산정하였다. 산정된 가변홍수기 제한수위 적용 효과를 분석하기 위하여 홍수조절용량을 산정하였고, 유역비 홍수량을 지표로 하여 홍수조절능력을 평가하였다. 향후 본 연구의 결과는 둑높이기 농업용저수지의 홍수기 제한수위 설정 및 관리, 운영 지침 개선에 있어 기초자료로 활용할 수 있을 것으로 사료된다.

• Korean Public Health Research
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• v.44 no.4
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• pp.25-34
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• 2018

Objective : This study aimed to examine the association Self-Rated Health(hereafter SRH) and Activities of Daily Living(hereafter ADL), Independent Activities of Daily Living(hereafter IADL) among Korean elderly. Methods : Using nationally representative cross sectional studies called 2014 Survey of living conditions and welfare needs of Korean elder persons. We used SRH as an independent variable, disabilities of ADL and IADL as dependent variables. Logistic regression was implemented and potential confounders such as socio-economic status, demographic characteristics and others were adjusted. Results : It was revealed that people who were female(than male) and 75 or more years old(than less than 75 years old) were shown to have poor SRH and disabilities of both ADL and IADL. In logistic regression model, poor SRH was associated with ADL and IADL disabilities. Especially, their association was more remarkable among male than among female. It can be understood that socio-economic contexts affect quality of life among elderly and SRH can be differently perceived by gender. Conclusions : Our notable findings showed that gender perspective is needed to understand SRH and daily living among elderly.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.214-220
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• 2021

SUGVs (Small Unmanned Ground Vehicles) are being used to conduct dangerous missions, such as EOD (explosive ordinance disposal), counter-terrorism operations, fire extinguishing and fire-fighting reconnaissance, reconnaissance of disaster areas, and surveillance of contact areas. Technology leading countries, the United States, United Kingdom, France, Germany, and Israel, have developed and operated various SUGVs for use in the military and civilian fields. The developed system was upgraded further based on additional requirements associated with data collected during the actual operation. The development trends of technology leading countries are an important indicator for the future development of SUGVs. In this study, the development trends and missions of SUGVs operating in the technology leading countries were analyzed. Based on the development trends of SUGVs in these countries, this paper discusses the features and design characteristics needed for the development of SUGVs in future military and civilian domains.

• Journal of Korean Society of Water and Wastewater
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• v.23 no.6
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• pp.871-879
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• 2009

The Korea has high population density, so the precipitation per capita is only one tenth to world average. The water resource in Korea is insufficient. But the leakage in the water distribution system is about 25%, and it is lower than other countries where water utilities are managed well. The pipelines' management also is getting worse because the leakage in the pipelines lower the ground density surrounding pipes. So, managing the leakage in the water distribution system is very important in the view of increasing the water resources and doing the efficient management of the pipeline system. Accordingly this study aimed to conduct a cause-analysis with scientific approaches considering key local factor related to water loss of distribution system and derive better performance indicators which are able to evaluate the real state of water loss management reasonably. Also this research aimed to develop a methodology capable of judging condition of infrastructure of water distribution system.

• Korean Journal of Construction Engineering and Management
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• v.10 no.2
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• pp.75-83
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• 2009

PPC stands for the percentage of weekly assignments completed. It makes it possible to improve the performance of production planning and control systems. Recently, the cases of PPC application have been increasing because PPC is easy to apply to construction site. However, to evaluate the average of PPC or analyze PPC as time passes has some problem ; if PPC is the same, the average it is evaluated equally although there are variabilities in production system. Therefore, In order to evaluate the character of PPC in process of production this paper suggests the method of the evaluating PPC by using coefficient of variability besides PPC measurement.

• Proceedings of the Korea Information Processing Society Conference
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• 2018.10a
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• pp.478-479
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• 2018

수부는 일상생활동작(ADL, activities of daily living)을 위한 중요 부위로 손상이나 장애가 있는 경우 재활치료를 통해 과제수행능력을 향상시킨다. 그러나 치료 과정은 주관적으로 진행되어 정확한 치료 성과를 위한 객관적 지표가 필요하다. 본 논문에서는 실제 수부 움직임을 추적할 수 있는 동작인식 장비인 립모션 컨트롤러와 Unity3D로 가상공간 상에서 구현된 Box&Block Test를 이용하여 수부 움직임에 대한 객관적인 데이터를 얻었다. 기존 Box&Block Test와 제안한 모션인식과 추적에 의한 수지손상 환자용 진단 및 치료시스템의 성능을 T검정 수행한 결과 통계적으로 유의미한 차이가 없음을 보였으며 수부 움직임의 정량적인 데이터를 통해 정확한 치료성과 판단의 가능성을 확인하였다.