• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.218-218
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• 2000

Advanced Vehicle Control Systems(AVCS) is one of the key elements in Intelligent Transportation Systems(ITS). This paper considers the problem of longitudinal control in vehicle platoon on a straight lane of a highway. In a very simplified situation, longitudinal vehicle dynamics contains many nonlinear elements. The nonlinear characteristics are mainly composed of an engine, a torque converter, and a drag force. In this paper, sliding control, one of nonlinear control methods, is applied to longitudinal automated vehicle control for platooning. Output feedback linearization is also simulated for comparison with the sliding control. Simulations for comparative study for the adopted controllers such as sliding control and output feedback linearization are peformed under the same conditions. This Paper aims at clarifying the characteristics of sliding control and output feedback linearization.

• 한국조사연구학회지:조사연구
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• 제7권2호
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• pp.97-122
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• 2006

2006년에 제1차 본조사에 들어간 '고령화연구패널조사(KLoSA)'는 HRS(미국), SHARE(유럽), ELSA(영국) 등과 연구네트워크를 구축하여 데이터베이스 사업과 공동연구를 추진하고 있다. '고령화연구패널조사'는 국가간 비교연구가 가능한 자료를 생산하기 위해서 다음 세 가지 조건을 고려하여 설계되었다. 첫째, 가족, 건강, 고용, 소득, 자산, 주관적 기대감 등 비교대상으로 삼은 조사들의 핵심적인 주제와 주요 조사영역을 일치시켰다. 둘째, 주요영역의 세부 항목은 우리나라의 제도적, 문화적 차이를 반영하도록 설계하였다. 우리나라의 공적연금과 의료보장제도의 특성 등 제도적 특성을 반영하여 설문을 구성하였으며, 고용상의 관행이나 금융상품의 범위도 고려하였다. 또한 문화적 차이에서 발생하는 가족간의 경제적 지원양태의 특징이나 재산관리상의 특성을 반영하도록 설문을 구성하였다. 마지막으로 척도의 선정에 있어서도 우리나라 고령자들에게 정확하게 의미가 전달할 수 있으면서도 국가간 비교연구도 가능한 방식의 척도를 개발하기 위하여 노력하였다.

• Journal of Ship and Ocean Technology
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• 제3권4호
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• pp.35-51
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• 1999

Fatigue strength assessment procedures have been implemented in the ship design rules by many classification societies. However, a large variation tin the details of the different approaches exists in practically all aspects influding load history assessment, stress evaluation and fatigue strength assessment. In order to assess the influences of thesd variations on the prediction of fatigue lives. a comparative study is organized by the ISSC Committee III.2 Fatigue and Fracture. A pad detail on the top of longitudinal hatch coaming of a panamax container vessel is selected for fatigue calculation. The work described in this paper is one set of results of this comparative study in which the ABS dynamics approach is applied. Through this analysis the following conclusions can be drawn. (1) With the original ABS approach, the fatigue life of this pad detail is very low, only 2.398 years. (2) The treatment of the stillwater bending moment in the ABS approach might be a source of conservatism. If the influence of stillwater bending moment is ignored, then the fatigue life for this pad detail is 7.036 years. (3) The difference between the nominal stress approach and the hot spot stress approach for this pad detail is about 26%.

• 상하수도학회지
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• 제20권5호
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• pp.667-676
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• 2006

This study was conducted to evaluate the effect of longitudinal baffle on hydrodynamic behavior within a certain full-scale sedimentation basin (flow rate per basin; $1,000m^3/d$). Comparative experimental investigations have been carried out on the sediment removal efficiencies and the sludge deposit distribution in the baffled and un-baffled sedimentation basin, respectively. From the results derived in the baffled and un-baffled sedimentation, the turbidity removal rate in the baffled sedimentation basin is about 38% higher than that in un-baffled. Also, the height of sludge deposit in the baffled sedimentation basin is approximately 20% lower, and the sludge concentration is 10% higher than those in un-baffled sedimentation basin. In order to explain the experimental results and investigate the effect of longitudinal baffle in more detail, we conducted Computational Fluid Dynamics (CFD) simulation. From the results of CFD simulation, the flow, especially in the near of outlet orifice, was more stable in the case of longitudinal baffled sedimentation basin than that in un-baffled basin. Also, it could be concluded that the longitudinal baffle made a fully developed flow more effective for sedimentation.

• 한국습지학회지
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• 제11권2호
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• pp.89-98
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• 2009

본 연구는 하천종단면에 정보엔트로피이론을 적용하여 평균하천경사, 하천경사 및 하천종단고도 결정방법을 제시하였다. 최대화된 엔트로피는 제약조건하에서 일정한 하천종단면의 확률분포를 만들며, 이와 같은 관계를 이용하여 평균하천경사, 하천경사 및 하천종단고도 산정식을 유도하였다. 충북 지방하천 정비기본계획에서 얻은 달천유역의 실측된 지형학적 인자를 사용하여 매개변수를 최소자승법으로 결정하였다. 유도된 평균하천경사와 하천종단고도식을 실제유역에 적용하였으며, 실측치와 잘 일치함을 나타낸다. 본 연구의 결과로부터 평균하천경사와 하천종단고도의 결정에 직접 적용할수 있을 것으로 판단된다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.410-413
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• 2008

In this study, we compare the mechanical properties of forged and machined bushings for an excavator track chain. The manufacturing process is explained in detail together with the procedure of making the specimens. The longitudinal tensile strength and elongation and the radial ring compression strength are measured for this comparison. It has been shown that the forged is much better than the machined with regard to both longitudinal tensile strength and radial ring compression strength but that both are the same in terms of longitudinal elongation.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.849-854
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• 2002

From the analysis results of some as-built drawings in national roadway bridges in Korea, many bridge piers are expected to show complex shear-flexural behaviour under earthquakes. But the previous research works about the seismic evaluation of bridges considered flexural behaviour RC piers only. In addition, the past bridge design specifications in Korea didn't include limitation on the amount of longitudinal lap splices in the plastic hinge zone of piers. Thus a large majority of non-seismically designed bridge piers in Korea may have lap splices in plastic hinge zone. In this study, prototype pier was selected among existent bridge piers whose failure mode is expected to be complex shear-flexural mode. And then, full scale and 1/2 reduced scale model RC piers with various longitudinal lap splice details were constructed. From the quasi static test results on these model RC piers, the effect of longitudinal lap splices on the seismic performance of bridges piers was analyzed. And the seismic capacity of the non-seismically designed shear-flexural RC piers was evaluated.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.114-122
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• 2002

The ASCE formula of lifeline.soil interaction force is the basis of semi-analytical relationship for buried pipelines subjected to longitudinal permanent ground deformation due to seismic induced liquefaction. However, since the ASCE formula has been developed based on the stiffness of non-liquefied region, it is needed to modify for the varied stiffness of liquefied region. With this object, the consideration of decreasing effect of soil stiffness in liquefied region is made: i.e. the spatial distributions of pipeline-soil interaction force in liquefied region. It means that the improved formula can reflect various patterns of permanent ground deformation more realistically. Through the comparative analyses using both the improved and ASCE formula, the applicability of the improved and the limitation of the ASCE formula and semi-analytical relationship are discussed. Also, relative influences of various parameters are evaluated for the clarification of behavior of pipeline subjected to longitudinal permanent ground deformation due to liquefaction.

• 대한조선학회 특별논문집
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• 대한조선학회 2009년도 특별논문집
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• pp.65-70
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• 2009

In case that tug boat pushes side structures of other large vessels to maneuver, it is required that contacted side structures of the maneuvered vessels have enough structural safety against tug push loads. The objective of this study is to evaluate the structural effect of carling which is installed between side longitudinal stiffeners. A comparative study of side structures with carling and without carling is performed to evaluate the effect of carling member by both FE analysis. According to the result, it is found that the carlings play effective role in the strength of side plates and side longitudinal stiffeners against tug push loads.

• 한국빅데이터학회지
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• 제5권2호
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• pp.155-170
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• 2020

본 연구의 목적은 서울시 중학생의 진로성숙도 예측 요인을 찾기 위해 머신러닝 기법(Decision Tree, Random Forest, XGBoost)을 서울교육종단연구 4~6차년도 데이터에 적용하였다. 적용에 따라 도출된 세 가지 머신러닝 모형의 변수 중요도와 각 지표별 성능을 확인하였다. 또한 XGBoostExplainer 패키지를 활용하여 모형을 해석하였으며, 데이터 전처리와 분석 모두 R과 R Studio를 활용하였다. 그 결과 각 모형별로 변수 중요도 순위는 다소 차이가 있으나 '성취목표', '창의성', '자아개념', '부모자녀와의 관계', '회복탄력성'이 높은 순위를 보였다. 또한 XGBoostExplainer를 활용하여 패널별 진로성숙도에 정적·부적 영향을 주는 요인을 탐색하였고, '성취목표'가 진로성숙도 예측 최우선 요인임을 찾을 수 있었다. 본 연구결과를 바탕으로 머신러닝 및 변수선택 방법의 비교연구와 서울교육종단연구 코호트별 비교연구가 수행되어야 함을 제언하였다.