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        검색결과 360

        141.
        2014.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Various inventory control theories have tried to modelling and analyzing supply chains by using quantitative methods and characterization of optimal control policies. However, despite of various efforts in this research filed, the existing models cannot afford to be applied to the realistic problems. The most unrealistic assumption for these models is customer demand. Most of previous researches assume that the customer demand is stationary with a known distribution, whereas, in reality, the customer demand is not known a priori and changes over time. In this paper, we propose a reinforcement learning based adaptive echelon base-stock inventory control policy for a multi-stage, serial supply chain with non-stationary customer demand under the service level constraint. Using various simulation experiments, we prove that the proposed inventory control policy can meet the target service level quite well under various experimental environments.
        4,000원
        142.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문에서는 유공형 형상의 GFRP 판으로 전단 보강된 플랫 플레이트의 전단거동을 실험을 통해 평가하였다. GFRP 판은 개구부가 있는 판의 형태로서 콘크리트와의 일체화 거동을 위하여 콘크리트에 매립하여 시공하였다. GFRP 판으로 전단보강된 플랫 플레이트의 전단 성능 실험을 위하여 총 7개의 시험체에 대한 전단 실험을 수행하였다. 실험 변수로는 전단 보강량, 전단 보강 간격을 선정하였다. GFRP 판의 전단 보강량에 따른 비교결과, 전단 보강량이 증가할수록 전단강도도 증가하는 결과를 보여주었다. GFRP 전단 보강 간격에 따른 비교결과, 전단 보강 간격이 0.3d 일 때 가장 높은 전단강도를 확인하였다. 실험결과를 바탕으로 KCI에서 제시하고 있는 전단강도식을 수정하여 GFRP 판에 적용이 가능한지 평가하였다.
        4,000원
        143.
        2014.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이 연구에서는 물량저감 철근상세를 갖는 중공 철근콘크리트 교각 시스템의 전용 설계프로그램과 소성설계 적용 결과를 제시하였다. 개발된 물량저감 철근상세는 경제성과 합리성을 갖으며 공사기간의 단축을 가져올 수 있다. 물량저감 중공 철근콘크리트 교각의 적용을 통해 경제성 평가를 수행하였다. 평가 결과 개발상세가 기존상세에 비해 구조적 합리성, 시공성, 그리고 경제성 등이 우수함을 확인하였다.
        4,000원
        144.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to investigate the seismic performance of hollow RC bridge columns with reinforcement details for material quantity reduction. The proposed reinforcement details provide economy, are rational and shorthen the construction periods. The accuracy and objectivity of the assessment process can be enhanced by using a sophisticated nonlinear finite element analysis program. Solution of the equations of motion is obtained by numerical integration using Hilber-Hughes-Taylor (HHT) algorithm. The adopted numerical method gives a realistic prediction of seismic performance throughout the input ground motions for several test specimens investigated. As a result, the proposed reinforcement details for material quantity reduction develop equal performance to that required for existing reinforcement details.
        4,000원
        145.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is intended to determine the validity of shear reinforcement by evaluating flexural performance in the hollow slab. The hollow slab is relatively light and second moment of inertia is large. Due to these characteristics, it can be used to slab system efficiently. Therefore the prediction of the structural behaviors is very important because of decrease of shear and flexural strength which is caused by hollow section of slab interior. In this study, the flexural test were performed to analyze the flexural capacity of the hollow slab w/ or w/o shear reinforcement. A total of six full scale specimens were tested. These specimens have three cases of reinforcing bar ratio, 0.009, 0.018 and 0.024. To verify the flexural behavior such as ultimate load, load-deflection and crack pattern, the flexural experiment were tested by using loading frame. Experimental results have shown that the flexural behavior are depend on the reinforcing bar ratio. Also the hollow slab with shear reinforcement have shown flexural behavior. Therefore, it is appropriate that the hollow slab is reinforced by shear reinforcement to improve the flexural performance of the hollow slab.
        4,000원
        146.
        2014.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Diagonal reinforced coupling beam of coupled shear walls can provide sufficient strength and stiffness to resist lateral force. However, the reinforcement details for coupling beams required by ACI 318 (2011) are difficult to construct because of the reinforcement congestion and confined interior area. This study presents experimental results about the seismic performance of coupling beams having bundled diagonal reinforcement to improve the workability. Experiments were conducted using half scaled precast coupling beams having an aspect ratio of 2.0. It was observed that the bundled diagonal reinforced coupling beams can develop seismic performance similar to the coupling beams with requirement details specified in ACI 318 (2011).
        4,000원
        147.
        2014.04 구독 인증기관·개인회원 무료
        This paper experimentally investigates the seismic performance of RC columns retrofitted by Super Reinforcement with Flexibility (SRF). A total of three specimens with a scale factor of 1/2 were constructed and tested in order to assess the structural behavior of the retrofitted RC columns. One specimen was a non-seismically designed column without any retrofitting method while others were retrofitted with either one or two layers of SRF by using urethane adhesive. The static cyclic testing with a constant axial load was conducted to assess the seismic performance of the retrofitted RC columns. It is concluded that the SRF retrofitting method increases the strength and ductility of the RC columns and can also impact on the failure mode of the columns.
        148.
        2014.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to investigate the seismic behavior of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction and to provide the details and reference data. Five hollow reinforced concrete bridge columns were tested under a constant axial load and a cyclically reversed horizontal load. The accuracy and objectivity of the assessment process can be enhanced by using a sophisticated nonlinear finite element analysis program. The adopted numerical method gives a realistic prediction of seismic performance throughout the loading cycles for several the investigated test specimens. This study documents the testing of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction and presents conclusions based on the experimental and analytical findings.
        4,000원
        149.
        2014.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to investigate the performance of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction. The proposed reinforcement details have economic feasibility and rationality and make construction periods shorter. A model of hollow reinforced concrete bridge columns was tested under a constant axial load and a quasi-static cyclically reversed horizontal load. As a result, proposed reinforcement details for material quantity reduction were equal to existing reinforcement details in terms of required performance. The companion paper presents the experimental and analytical study for the performance assessment of hollow reinforced concrete bridge column systems with reinforcement details for material quantity reduction.
        4,000원
        150.
        2013.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The core aim of this paper is to empirically scrutinize a strength characteristic and ductility of the beam-column frame of reinforced with steel subjected to the cyclic lateral load. First and foremost, I the author embarks upon making four prototypes vis-à-vis this research. Through this endeavour, the author has analysed cyclic behavior, fracture shape, ductility and energy dissipation of the normal beam-column frame and a beam-column frame of reinforced with steel. In addition, the survey has revealed the exact stress transfer path and the destructive mechanism in order to how much a beam-column frame of reinforced with steel has resistance to earthquake regarding all types of building, as well as school construction. To get the correct data, the author has compared the normal beam-column frame and three types of the beam-column frame of reinforced with steel following these works, the characteristic of cyclic behavior, destructive mechanism, ductility, and Energy dissipation of normal beam-column frame and a beam-column frame of reinforced with steel have been examined clearly.
        4,200원
        151.
        2013.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to investigate the inelastic behavior of hollow reinforced concrete bridge column sections with reinforcement details for material quantity reduction and to provide the details and reference data. Among the numerous parameters, this study concentrates on the shape of the section, the reinforcement details, the diameter of the transverse reinforcement and loading types. Eighteen column section specimens were tested under quasi-static monotonic loading. In this study, the computer program RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology) was used. A modified lateral confining effect model was adopted for the hollow bridge column sections. This study documents the testing of hollow reinforced concrete bridge column sections with reinforcement details for material quantity reduction and presents conclusions based on the experimental and analytical findings.:
        4,200원
        152.
        2013.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is intended to examine the tDCS and Morris Water maze training in Alzheimer’s disease(AD) rats on Tau protein expression. Experiment groups were divided into four groups and assigned 16 rats to each group. Group Ⅰ was a control group(AD induced by scopolamine); Group Ⅱ was a experimental control group(AD injured by scopolamine and treatment tacrine); Group Ⅲ was a group of tDCS application after AD injured by scopolamine; Group Ⅳ was a group of morris water maze training after AD injured by scopolamine. In cognition test, the outcome of group Ⅱ was significantly lower than the groups(p<.001). and group Ⅲ, Ⅳ were significantly low result at 14 days(p<.05). In histological finding, the experimental groups were destroy of micro vessels and finding of cell atropy and swelling. Group Ⅲ, Ⅳ were decreased in degeneration of liver and kidney cells. In immuno- histochemistric response of BDNF and tau protein in hippocampus, BDNF expression of Group Ⅱ was more increase than the other groups. and increase of BDNF expression was Ⅲ, Ⅳ were higher than group Ⅰ at 21 days. Tau protein expression of Group Ⅱ was more decrease than the other groups. and decrease of Tau protein expression was Ⅲ, Ⅳ were lower than group Ⅰ at 21 days. These result suggest that improved tDCS and morris water maze training after scopolamine induced is associated with dynamically altered expression of BDNF and Tau protein in hippocampus and that is related with cognitive function.
        4,000원
        153.
        2013.04 구독 인증기관 무료, 개인회원 유료
        본 연구는 외부 온도변화에 따른 GFRP 횡구속 콘크리트 압축부재의 강도특성에 대한 성능을 조사, 평가하였다. 일반적으로 외부 보강재에 의하여 구속된 압축부재의 성능평가는 과거 많은 연구자들에 의하여 수행되어 왔는데 복합재료를 이용한 구속 콘크리트의 경우, 복합재료 자체의 외부환경(자외선, 습도, 온도 등)에 대한 단점으로 인하여 상대적으로 뛰어난 중량 대비 구속에 따른 압축성능 개선효과에도 불구하고 그 신뢰성에 많은 어려움을 겪어왔다. 본 연구는 이들 콘크리트 횡구속 복합재료 보강재에 대하여 고온으로의 외부온도 변화 시 FRP로 횡구속된 콘 크리트 압축부재의 강도변화 거동을 통한 FRP보강재의 구속효과에 대한 변화를 알아보기 위하여 실험적 연구를 수행하였다. 수행된 실험연구에서는 건설용 보강재료로 가장 많이 활용되는 GFRP를 대상으로 상온(20℃), 100℃, 15 0℃, 200℃까지 온도를 상승하여 실험하였으며 가온 시 노출시간의 경우 국외선행연구 및 사전 모의실험을 통하여 약 60분간 시험체를 설정온도에 노출시켜 실험을 진행하였다. 제작된 시험체들은 모두 KSF 2405의 절차에 따라 압축실험을 실시하였으며 그 결과 외부온도가 증가함에 따라 GFRP보강재의 횡 구속력이 점진적으로 감소되어 GFRP 구속효과가 100℃, 150℃, 200℃에서 각각 약 8%, 29%, 27% 감소하는 것으로 나타냈다.
        3,000원
        154.
        2012.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The characteristics of abrasive wear on sliding speed of glass fiber reinforcement (GF/PUR) composites were investigated at ambient temperature by pin-on-disc friction test. The cumulative wear volume, friction coefficient and surface roughness of these materials on sliding speed were determined experimentally. The major failure mechanisms were lapping layers, deformation of resin, ploughing, delamination, and cracking by scanning electric microscopy (SEM) photograph of the tested surface. As increasing the sliding speed the GF/PUR composites indicated higher friction coefficient. The surface roughness of the GF/PUR composites was increased as the sliding speed was higher in wear test.
        4,000원
        155.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 학교 건물의 구조적 성능 평가를 통한 내진보강에 대한 연구이다. 본 연구의 목적은 학교 건물의 구조적 성능평가를 통하여 안전성과 사용성을 고려한 구조보강방안을 비교분석하고 합리적 내진 보강안을 제시하여 보다 지진에 안전한 건축물을 유지하는데 도움 이 되고자 한다. 이 목적을 위해 기존의 학교건물을 연구 대상으로 선정하여 내진성능평가를 실시하고 내진 보강안을 제시하였다. 본 연구의 방법은 기존의 철근콘크리트 학교건물을 대상으로 1차 내진 성능평가와 2차 내진 성능평가를 실시하였다. 위와 같은 방법으로 내진성능평가를 하여 그 결과를 분석하고 내진보강방안을 제시(강재댐퍼, 탄소막대보강재)하였다. 제시된 내진 보강방안을 대상 건축물에 적용하여 내진보강 전, 후의 내진성능평가를 통해 종합적인 결과를 도출 하였다.
        4,000원
        156.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, composite laminate cantilever type cylindrical shells with edge-stiffeners are analyzed. A versatile 4-node flat shell element which is useful for the analysis of shell structures is used. An improved flat shell element is established by the combined use of the addition of non-conforming displacement modes and the substitute shear strain fields. Two models by load conditions are considered. Load type A and B are loaded by point load at the free edge and line load respectively. A various parameter examples are presented to obtain proper stiffened length and stiffened thickness of edge-stiffeners. It is shown that the thickness of shell can be reduced minimum 30% by appropriate edge-stiffeners.
        4,000원
        157.
        2012.04 구독 인증기관·개인회원 무료
        The seismic design range for the national public facilities and power plant is expanded such as it becomes the earthquake Disaster Relief Act with the finance since 2008 as the seismic design concept is highly regarded, etc. The reinforcement of the brace is essential for the seismic performance security of the structure which is unable to be satisfied the current seismic design criteria. The tension brace in which the slenderness ratio is big was designed to the unique lateral force resistive element. And the buckling is generated in the first stage and it is unable to exhibit the structural capability. In this research, the buckling strength improvement the reinforcing method of the suggested tension brace tries to be verified through the experiment.
        158.
        2012.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 논문은 케이블 돔 구조물의 브레이싱 및 막재 보강 효과에 따른 비교분석을 하고자 한다. 텐세그러티 구조시스템은 초기응력의 도입을 통해 자기평형을 가지는 구조물로서 연속적으로 연결되어 있는 인장재와 이들을 연결해 주는 불연속의 압축재로 구성되어 있다. 본 연구에서는 경량화한 Hybrid 구조물인 케이블 돔의 불안정 현상이 면내 비틀림에 의해 발생함을 기본 Geiger형과 Zetlin형 모델에 브레이싱 및 막재를 보강하여 발생되는 효과를 알아본다. 또한, 쉘형 구조물의 구조불안정 거동이 초기조건에 매우 민감하게 반응하므로 초기형상불완전량 0.1%를 도입하여, 초기조건에 대한 영향도 알아본다.
        4,000원
        160.
        2011.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Korean Quality Innovation Movement has achieved excellent results for the past 10 years as Hard Single PPM, the next step should be Smart Single PPM. In this new version of PPM, the systematic or structural problems found through thorough examination of p
        4,000원