• 한국산학기술학회논문지
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• 제16권10호
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• pp.6860-6868
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• 2015

본 연구에서는 국내 도시가스 일일 수요 예측에 대한 문제를 다룬다. 정확한 일일 수요 예측은 안정적인 도시가스의 수급을 위해서 필수적인 사항으로 실제 가스 공급기관의 일상 업무에 해당한다. 본 연구에서는 수요예측 방법을 고안하기 위하여 일일 도시가스 수요 시계열에 대한 데이터 분석을 수행하였으며, 예측일 수요에 영향을 주는 주요한 요인으로 직전일 수요, 기온, 요일 등을 파악하였다. 본 연구에서는 이러한 요인들을 고려한 회귀 모형과 국내 도시가스 수요 특성에 맞는 선별적 샘플링 절차를 제안하였다. 제안 모형과 선별적 샘플링 절차로 구성된 예측 방법의 성능 검증을 위하여 실제 도시가스 수요에 대한 예측을 수행하였다. 문헌에 소개된 기존 방법과 예측 성능을 비교한 결과, 본 연구에서 제안한 방법의 평균절대백분율오차는 약 2.22%로서 개선 비율은 대략 7%에 해당한다.

• 보건행정학회지
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• 제11권1호
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• pp.131-152
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• 2001

Public health system and public health practice have changed over the past decades as the result of social and epidemiologic changes. New public health concept emphasizes leadership, strategical thinking, systematic planning and effective performance to identify and solve complex health problem In Korea, the role of Health Center has been expanded rapidly. However there is strong suspicion that Health Center can achieve their mission. This paper aims at understanding what is the needed functions of Health Center and which of its aspects needs improvement. The main results of this study are summarizes as follows. District Health Law does not address the core functions of Health Center. The staffs of Health Center have difficulties in prioritizing their services. The recent attempt to restructure Health Center and change delivery pattern of public health services ended with only limited success. To effectively confront threats to the public's health, the three major function of Health Center must be ${\circled}1$ modifying individual behavior and lifestyle, ${\circled}2$ improving social and economic conditions, and ${\circled}3$ reforming health policies. Better results do not come from setting new functions only; they come from understanding and improving the processes that will then leads to better outcome. We recommend that policy-makers focus economic evaluation of public health programs, building and spreading of the scientific evidence of programs, linkage of public health research and public health program. The criteria of delegation of public health service to private sector is urgently needed. Making community health information data available on a routine basis to providers, managers and researchers of public health services helps promote the efficiency of the overall operation of public health system.

• 대한골관절종양학회지
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• 제13권2호
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• pp.185-189
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• 2007

영상기술과 수술 술식의 발전으로 골반골의 악성종양에서 내 골반골 절제술이 보편화되었으나 절제 후 골 결손의 기능적인 재건 방법에 대하여는 아직 논란의 여지가 많다. 골반환 재건술식 중 열처리한 자가골과 대퇴골 전치환물을 조합하는 방법은 생역학적이며 해부학적인 적합성이 장점으로 적절한 증례를 선택하면 좋은 결과를 얻을 수 있다. 그러나 이 술식 후 감염이나 기계적인 파괴가 발생 시 내고정물과 자가골 전부를 제거하는 것이 불가피하다. 이런 경우 가관절을 형성하더라도 심한 하지 단축이 문제가 된다. 저자들은 이런 문제점을 해결하기 위해 대퇴골두를 제거하지 않고 골반골만 열처리 후 재삽입 한 1례를 보고하고자 한다.

• 한국전산구조공학회논문집
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• 제16권4호
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• pp.407-417
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• 2003

최근 구조최적화분야에서 활발하게 사용되고 있는 유전알고리즘은 해집단을 운용하기 때문에, 많은 반복수와 적응도 평가를 위하여 해집단의 수에 해당하는 구조해석을 필요로 하며, 또한 교배율과 돌연변이율 등의 파라미터에 따라 알고리즘의 성능이 변화하므로 문제에, 따라 적합한 파라미터 설정이 필요한 근본적인 단점을 지니고 있다. 본 연구에서는 기존 유전알고리즘의 단점을 극복할 수 있는 복합유전알고리즘을 마이크로유전알고리즘과 단순유전알고리즘을 결합한 형식으로 그리고, 최적화에 요구되는 연산을 다수의 개인용 컴퓨터에서 동시에 분산하여 수행할 수 있는 고성능 분산 복합유전알고리즘으로 개발하였다. 개발된 알고리즘은 철골 가새골조 구조물의 최소중량설계에 적용하여 그 성능을 평가하였다.

• 디지털융복합연구
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• 제13권1호
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• pp.495-502
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• 2015

청소년들의 건강한 자아정체성 형성을 목적으로 하는 "(가제) SAVE ME, LOVE ME" 라는 심리 기능성게임 시나리오의 주제는 조건 없는 사랑(무조건적인 사랑)을 자원으로 딜레마들을 해결하는 과정에 의한 내부적 승인 획득이다. 1인칭 시점 액션게임으로 청소년의 일상적인 삶의 딜레마를 다루는 이 게임의 특징은 청소년들이 받는 여러 심리적 스트레스를 치료하기 위해 종교 지혜 내러티브 중 기독교 예수의 '돌아온 탕자' 비유의 모티브를 사용한 것이다. 게임의 기획 의도는 다양한 스테이지 별로 청소년들의 건강한 자아정체성을 해치는 위협요인들의 상징을 배치, 여러 캐릭터가 제공하는 이야기들이나 몬스터를 파괴하는 등의 액션을 통해 긍정적인 자아상 확립을 돕는 것이다. 게임의 장르는 모바일 게임을, 게임 형식으로는 다양한 형식의 인터랙션이 가능한 액션 게임을 채택하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 International Symposium on GPS/GNSS Vol.1
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• pp.171-174
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• 2006

A large number of service providers in countries all over the world have established GNSS reference station networks in the last years and are using network software today to provide a correction stream to the user as a routine service. In current GNSS network processing, all the geometric related information such as ionospheric free carrier phase ambiguities from all stations and satellites, tropospheric effects, orbit errors, receiver and satellite clock errors are estimated in one centralized Kalman filter. Although this approach provides an optimal solution to the estimation problem, however, the processing time increases cubically with the number of reference stations in the network. Until now one single Personal Computer with Pentium 3.06 GHz CPU can only process data from a network consisting of no more than 50 stations in real time. In order to process data for larger networks in real time and to lower the computational load, a federated filter approach can be considered. The main benefit of this approach is that each local filter runs with reduced number of states and the computation time for the whole system increases only linearly with the number of local sensors, thus significantly reduces the computational load compared to the centralized filter approach. This paper presents the technical aspect and performance analysis of the federated filter approach. Test results show that for a network of 100 reference stations, with the centralized approach, the network processing including ionospheric modeling and network ambiguity fixing needs approximately 60 hours to process 24 hours network data in a 3.06 GHz computer, which means it is impossible to run this network in real time. With the federated filter approach, only less than 1 hour is needed, 66 times faster than the centralized filter approach. The availability and reliability of network processing remain at the same high level.

• 대한두개안면성형외과학회지
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• 제20권1호
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• pp.10-16
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• 2019

Background: Physicians tend to overcorrect when applying the acellular dermal matrix for reconstructive option because of volume decrement problem after absorption comparing with initial volume. However, there are no studies on the exact volume decrement and absorption rate with commercial products in South Korea. To figure out absorption rate of acellular dermal matrix product in South Korea (Megaderm), authors designed this experiment. Methods: Nine mice were used and randomly divided into three groups by the time with sacrificing. The implant (Megaderm) was tailored to fit a cuboid form ($1.0cm{\times}1.0cm$ in length and width and 2.0 mm in thickness). A skin incision was made at anterior chest with blade #15 scalpel with exposing the pectoralis major muscle. As hydrated Megaderm was located upon the pectoralis major muscle, the skin was sutured with Ethilon #5-0. After the surgical procedure, each animal group was sacrificed at 4, 8, and 12 weeks, respectively, for biopsies and histological analysis of the implants. All samples were stained with routine hematoxylin and eosin staining and Masson's trichrome staining and the thickness were measured. A measurements were analyzed using Friedman test. Statistically, the correlation between thicknesses of Megaderm before and after implantation was analyzed. Results: After sacrificing the animal groups at postoperative 4, 8, 12 weeks, the mean tissue thickness values were $2.10{\pm}1.03mm$, $2.17{\pm}0.21mm$, and $2.40{\pm}0.20mm$ (p= 0.368), respectively. The remaining ratios after absorption comparing with after initial hydrated Megaderm were 82.7%, 85.4%, and 94.5%, respectively. In histopathological findings, neovascularization and density of collagenous fiber was increased with time. Conclusion: Author's hypothesis was absorption rate of implant would be increased over time. But in this experiment, there is no statistical significance between mean absorption thickness of implant and the time (p= 0.368). Also it can be affected by graft site, blood supply, and animals that were used in the experiment.

• Nutrition Research and Practice
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• 제15권4호
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• pp.504-515
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• 2021

BACKGROUND/OBJECTIVES: Malnutrition risk and malnutrition among the elderly is a public health concern. In combating this health-related problem, it is critically important to evaluate the risk factors in a multidimensional way and to apply appropriate nutrition intervention based on the results. SUBJECTS/METHODS: A cross-sectional study was conducted on 215 elderly patients (32.6% male, 67.4% female) in a geriatric outpatient clinic of a hospital in Turkey. Nutritional questionnaires that incorporated the 24-h recall method were applied to determine general characteristics of patients, their health status, nutritional habits, and daily energy and nutrient intakes. Mini Nutritional Assessment was used to determine nutritional status. Relevant anthropometric measurements were obtained. RESULTS: The subjects' mean age was 76.1 ± 7.0 years, and the prevalence of malnutrition (n = 7) and risk of malnutrition (n = 53) among the 215 subjects was 3.2% and 24.7%, respectively. Patients with malnutrition or risk of malnutrition were found to be single, have a depression diagnosis, in an older age group, have less appetite, more tooth loss, have more frequent swallowing/chewing difficulty, and have more frequent meal skipping. In addition, mean daily energy, carbohydrate, fat, fiber, vitamin E, vitamin B1, vitamin B2, vitamin B6, vitamin C, folates, potassium, magnesium, phosphorus, iron intake, and water consumption were found to be statistically significantly low in subjects with malnutrition or risk of malnutrition. After performing regression analysis to determine confounding factors, malnutrition risk was significantly associated with marital status, loss of teeth, appetite status, and depression. CONCLUSIONS: Routine nutritional screening and assessment of the elderly should be performed. If nutritional deficiencies cannot be diagnosed early and treated, self-sufficiency in the elderly may deteriorate, resulting in increased institutionalization.

• 한국인터넷방송통신학회논문지
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• 제22권6호
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• pp.173-178
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• 2022

최근, 소셜 네트워크 서비스에서 딥러닝을 활용한 추천시스템이 활발하게 연구되고 있다. 하지만 딥러닝을 이용한 추천시스템의 경우 콜드스타트 문제와 복잡한 연산으로 인해 늘어난 학습시간이 단점으로 존재한다. 본 논문에서는 사용자의 메타데이터를 활용하여 사용자 맞춤형 운동 루틴 추천 알고리즘을 제안한다. 본 논문에서 제안하는 알고리즘은 메타데이터(사용자의 키, 몸무게, 성, 등)를 입력받아 설계된 모델에 적용한다. 본 논문에서 제안한 운동 추천시스템 모델은 matrix factorization 알고리즘과 multi-layer perceptron을 활용한 neural collaborative filtering(NCF) 알고리즘을 기반으로 설계된다. 제안된 모델은 사용자 메타데이터와 운동 정보를 입력받아 학습을 진행한다. 학습이 완료된 모델은 특정 운동이 입력되면 사용자에게 추천도를 제공한다. 실험 결과에서 제안하는 운동 추천시스템 모델이 기존 NCF 모델보다 10% 추천 성능 향상과 50% 학습 시간 단축을 보였다.

• Nuclear Engineering and Technology
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• 제55권4호
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• pp.1439-1447
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• 2023

The fuel cycle characteristics of the IVG.1M reactor were studied within the framework of the research reactor conversion program to modernize the IVG.1M reactor. Optimum use of the nuclear fuel and reactor was achieved through routine methods which included partial fuel reloading combined with scheduled maintenance operations. Since, the additional problem in planning the fuel cycle of the IVG.1M reactor was the poisoning of the beryllium parts of the core, reflector, and control system. An assessment of the residual power and composition of spent fuel is necessary for the selection and justification of the technology for its subsequent management. Computational studies were performed using the MCNP6.1 program and the neutronics model of the IVG.1M reactor. The proposed scheme of annual partial fuel reloading allows for maintaining a high reactor reactivity margin, stabilizing it within 2-4 β_eff for 20 years, and achieving a burnup of 9.9-10.8 MW × day/kg U in the steady state mode of fuel reloading. Spent fuel immediately after unloading from the reactor can be placed in a transport packaging cask for shipping or safely stored in dry storage at the research reactor site.