• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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• pp.313-318
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• 1996

In this paper, a parametric study of the unbalance response and the stability is carried out to show the influence of seal parameters on the response of rotor. The seal parameters optimized are the seal clearance and the seal length. The minimum quantity of a Q factor in the critical speed and the maximum quantity of a logarithmic decreement in the operating speed, avoiding the reign of resonance, are the objective function. This paper describes a new approach to find a seal parameter of rotor system. The optimization method is used genetic algorithms, which are search algorithms based on the mechanics of natural selection and natural genetics. The results show the capability of this method and indicate that an optimal design of seals can improve the unbalance and the stability of rotor.

• ETRI Journal
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• 제43권4호
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• pp.580-593
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• 2021

When operating in confined spaces or near obstacles, collision-free path planning is an essential requirement for autonomous exploration in unknown environments. This study presents an autonomous exploration technique using a carefully designed collision-free local planner. Using LiDAR range measurements, a local end-point selection method is designed, and the path is generated from the current position to the selected end-point. The generated path showed the consistent collision-free path in real-time by adopting the Euclidean signed distance field-based grid-search method. The results consistently demonstrated the safety and reliability of the proposed path-planning method. Real-world experiments are conducted in three different mines, demonstrating successful autonomous exploration flights in environment with various structural conditions. The results showed the high capability of the proposed flight autonomy framework for lightweight aerial robot systems. In addition, our drone performed an autonomous mission in the tunnel circuit competition (Phase 1) of the DARPA Subterranean Challenge.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2018년도 학술발표회
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• pp.157-157
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• 2018

A reliable and accurate downscaling model which can provide climate change information, obtained from global climate models (GCMs), at finer resolution has been always of great interest to researchers. In order to achieve this model, linear methods widely have been studied in the past decades. However, nonlinear methods also can be potentially beneficial to solve downscaling problem. Therefore, this study explored the applicability of some nonlinear machine learning techniques such as neural network (NN), extreme learning machine (ELM), and ELM autoencoder (ELM-AE) as well as a linear method, least absolute shrinkage and selection operator (LASSO), to build a reliable temperature downscaling model. ELM is an efficient learning algorithm for generalized single layer feed-forward neural networks (SLFNs). Its excellent training speed and good generalization capability make ELM an efficient solution for SLFNs compared to traditional time-consuming learning methods like back propagation (BP). However, due to its shallow architecture, ELM may not capture all of nonlinear relationships between input features. To address this issue, ELM-AE was tested in the current study for temperature downscaling.

• Journal of Acupuncture Research
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• 제25권2호
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• pp.199-210
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• 2008

Backgrounds : Electroacupuncture(EA) is commonly used in treatment of various disease. Despite an extensive evidence-base guiding the selection of stimulation parameters, little methodologically robust research regarding the level of intensity and frequency in need to provide effective doses. Objectives : This study is evaluated effects of various intensities and frequencies of EA's stimulation at $ST_{36}$, Zusanli, with sex and age in rats. Methods : In this study, we measured the effects of EA treatment on transfer capability of small intestine in rats. Under anesthesia, two intensities, 1, 5mA with three different frequencies, 2, 50, 100Hz were applied to the groups divided with sex and age for 30minutes. Results : 1mA-2Hz, 5mA-2, 100Hz in male and 1mA-2, 50, 100Hz in female without distinction of age elicited an increasing trend in transfer capability of small intestine. In case of 2Hz in male, it showed the effects of EA without strength or weakness of stimulation and it need 100Hz stimulation additionally with age. In the groups of 1mA-2Hz, 5mA-2Hz in male and 1mA-2Hz, 1mA-100Hz, we elicited the decreasing trend with growing of weeks-old in male. Conclusions : With this result, it was suggested that we should consider a correlation of sex, age and EA's intensities, frequencies for the efficient EA.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.772-776
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• 2004

This paper proposes an interference avoidance approach for Constraint-Based Routing (CBR) algorithm in the Multi-Protocol Label Switching (MPLS) network. The MPLS network itself has a capability of integrating among any layer-3 protocols and any layer-2 protocols of the OSI model. It is based on the label switching technology, which is fast and flexible switching technique using pre-defined Label Switching Paths (LSPs). The MPLS network is a solution for the Traffic Engineering(TE), Quality of Service (QoS), Virtual Private Network (VPN), and Constraint-Based Routing (CBR) issues. According to the MPLS CBR, routing performance requirements are capability for on-line routing, high network throughput, high network utilization, high network scalability, fast rerouting performance, low percentage of call-setup request blocking, and low calculation complexity. There are many previously proposed algorithms such as minimum hop (MH) algorithm, widest shortest path (WSP) algorithm, and minimum interference routing algorithm (MIRA). The MIRA algorithm is currently seemed to be the best solution for the MPLS routing problem in case of selecting a path with minimum interference level. It achieves lower call-setup request blocking, lower interference level, higher network utilization and higher network throughput. However, it suffers from routing calculation complexity which makes it difficult to real task implementation. In this paper, there are three objectives for routing algorithm design, which are minimizing interference levels with other source-destination node pairs, minimizing resource usage by selecting a minimum hop path first, and reducing calculation complexity. The proposed CBR algorithm is based on power factor calculation of total amount of possible path per link and the residual bandwidth in the network. A path with high power factor should be considered as minimum interference path and should be selected for path setup. With the proposed algorithm, all of the three objectives are attained and the approach of selection of a high power factor path could minimize interference level among all source-destination node pairs. The approach of selection of a shortest path from many equal power factor paths approach could minimize the usage of network resource. Then the network has higher resource reservation for future call-setup request. Moreover, the calculation of possible path per link (or interference level indicator) is run only whenever the network topology has been changed. Hence, this approach could reduce routing calculation complexity. The simulation results show that the proposed algorithm has good performance over high network utilization, low call-setup blocking percentage and low routing computation complexity.

• 한국건설관리학회논문집
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• 제16권2호
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• pp.12-20
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• 2015

공공프로젝트 발주자들에게 VE의 중요성이 점증되고 있다. 본 연구에서는 VE 공공발주체계의 과학화, 시스템화를 통하여 공공발주자의 의사결정을 객관화시키고 발주체계 관련자들의 상호신뢰 회복을 위한 의사결정 지원체계의 구축을 위하여, 공공발주자에게 미치는 VE 프로젝트 발주체계의 영향력 분석에 대한 DB를 구축하는데 그 목적이 있다. 이에 국내의 VE 수행현황 분석을 통하여 수행체계의 문제점을 고찰하고, 도출된 문제점의 개선을 위하여 건설VE 수행사례를 통한 프로젝트 발주 시 고려하여야 할 VE 영향요소를 추출하여 설문결과에 대한 회귀분석 및 요인분석을 통하여 전체의 60%이상의 영향력을 가지는 15개의 영향요소를 도출한다. 도출된 영향요소에 대한 AHP분석을 통하여 프로젝트 생애주기 동안의 각 단계에 미치는 영향력을 분석하여 제시하였다.

• 한국지능시스템학회논문지
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• 제17권4호
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• pp.563-568
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• 2007

본 논문은 가중 퍼지소속함수 기반 신경망(Neural Network with Weighted Fuzzy Membership Functions, NEWFM)을 이용하여 클래스의 분류강도를 구하고 비선형 시계열 추이선을 예측하는 방안을 제안하고 있다. NEWFM에 의하여 추출된 가중퍼지 소속함수(BSWFM)를 이용하여 입력값에 대한 분류강도를 구하게 되고, 이들에 대한 가중평균 역퍼지화를 통하여 비선형 시계열 추이선을 작성한다. 실증분석결과 NEWFM은 목표 클래스로 설정된 GDP에 대하여 92.22%의 분류성능을 보여 주었다. 따라서 동 비선형 시계열 추이선은 대표적인 경기지표인 GDP 추이에 비교적 높은 유사도를 나타내는 가운데 분석대상기간인 제5순환기-제8순환기 중 정점(peak)에서 평균 12개월, 저점(trough)에서 평균 6개월의 선행성(look-ahead)을 보여 줌으로써 경기변동에 앞서 상당기간의 시차를 둔 예측지표로서 활용가능성이 입증되었다. NEWFM은 그 특징선택(feature selection)에 의하여 선행지표 10개 중 3개의 축소를 기할 수 있게 해 줌으로써 보다 적은 수의 경제지표를 가지고도 분류성능을 90.0%에서 92.22%로 향상을 기하는 가운데 효율적인 예측기능을 수행할 수 있음이 입증되었다.

• 한국건설관리학회논문집
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• 제15권5호
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• pp.71-81
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• 2014

국내 건설투자가 점차 감소되는 환경 변화 속에서 해외 CM시장으로의 진출에 대한 중요성이 대두되고 있으며, 성공적인 CM시장의 진출 확대를 위해서는 건설사업 생애주기 관점에서의 CM 업무기능의 역량 강화가 요구된다. 본 연구에서는 CM산업 제도변화를 고찰하고, 생애주기별 CM업무 비중을 분석하였다. 분석 결과, 국내공공 CM사업은 시공단계에 업무 투입 노력이 78%이상 집중되어 시공전단계의 기술경쟁력 축적을 제도적으로 저해하고 있는 현실이다. 즉, 우리나라 CM기업이 해외시장 진출을 위한 생애주기관점에서의 기술 경쟁력 확보를 위해서는 CM기업 자체적인 역량 향상 노력도 중요하지만, 이에 못지않게 '인력배치 기준' 등에 대하여 유연성을 보장하는 제도적인 뒷받침이 필요하다. 이러한 배경에서, 본 연구에서는 '경직된 인력배치기준의 개선', '비합리적 CM대가기준의 개선', 'CM선정방식의 개선', '불합리한 업무범위 결정의 개선', '발주자 사업관리 역량 평가'와 같이 5가지 측면에서 우리나라 CM산업의 발전 및 해외시장 진출 확대 기반 마련을 위한 정책 및 제도 개선방안을 제시하였다.

• 한국응급구조학회지
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• 제14권3호
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• pp.95-105
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• 2010

Purpose: This study aims to investigate the operation of continuing education system and continuing education program for emergency medical technician in Korea, Japan and United States and develop reasonable operating scheme of continuing education and curriculum in order to provide the base data for the improvement of continuing education for the improved practice capability and its maintenance, Method: The overall review of continuing education for domestic 1st class emergency medical technician was performed and also the content of continuing education for Emergency Medical Technician - Paramedic in the United States and Paramedics of Fire Department with the license for the paramedic in Japan, have been analyzed through literature, books, articles, agencies' data, laws, and internet date. Result: Hours for domestic continuing education was 4-8 hours and it was only 3-11% compared to 72 hours in the United States and 128 hours in the Japan. And with respect to the types and methods of programs, there were differences both in quantity and quality. Conclusion: As an education, providing and supplementing the changed content and technical information for the improvement of the capability and qualification of emergency medical technician, selection of education hours and various continuing education should be continuously and regularly provided and conducted. The introduction of various continuing education system and programs for this is considered to be required.

• KIEAE Journal
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• 제10권4호
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• pp.9-17
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• 2010

The purpose of this study is to draw out objective bases for selecting various applicable facilities in case of the establishment of rainwater management strategies. To do so, sixteen facilities were selected from decentralized rainwater management systems that induce rainwater infiltration and detention as well as centralized end-of-pipe type infiltration and detention facilities in local areas. With these facilities, it attempted to evaluate them in terms of sustainability, pollutant elimination, flood control capacity and costs and subsequently analyzed correlations between each characteristic. The outcomes of the analysis were as follows: First was the analysis of characteristics between decentralized rainwater management systems and end-of-pipe rainwater management systems. From the decentralized rainwater management systems, the mulden-rigolen system and grass swale at street level had the highest in the total of the four items while the totals of the underground detention tank and temporary detention site were highest in end-of-pipe rainwater management systems. After analyzing the correlation between different types of facilities and each variable, it can be said that decentralized rainwater management systems have a higher correlation than end-of-pipe rainwater management systems in terms of sustainability whereas the latter are better in flood control capacity than the former. Second, the analysis of correlation in variables of each facility is as follows: first, there is a negative correlation between sustainability value and flood control capacity value; and there is a positive correlation between flood control capability and pollutants elimination. In addition, it revealed that the higher the flood control and pollutant elimination capability the higher the facility costs. Based on these assessments, it is possible to use them as objective selection criteria for facility application in case of site development project or complex plan.