• 대한조선학회논문집
• /
• 제56권3호
• /
• pp.231-241
• /
• 2019

In this study, a simplified analysis method was developed to evaluate the fatigue damage of an ice-going ship under broken ice condition. The global ice load, which is essentially calculated at the design stage of the Arctic vessel, and the hull form information were used to estimate the local ice load acting on the outer-shell of the ship. The local ice load was applied to the finite element analysis model, and the Weibull parameters for the target fatigue point were derived. Finally, fatigue damage was evaluated by applying the S-N curve and the Palmgren-Miner rule. For the verification of the proposed method, numerical analyses using direct approach were performed for the same conditions. A numerical model that implements the interaction between ice and structure was introduced to verify the local ice load and the stress calculated from the proposed method. Finally, the fatigue analyses of the Baltic Sea for actual ice conditions were performed, and the results of the proposed method, the method using numerical analysis, and the LR method were compared.

• 한국경영과학회:학술대회논문집
• /
• 한국경영과학회 2005년도 추계학술대회 및 정기총회
• /
• pp.189-206
• /
• 2005

Much of work on network externality assumed network effects are dependent on the network size. Therefore, very little consideration is given to the view that marginal benefits from joining the network may not increase with the network size if consumer benefits come from the direct interaction with neighbors, namely local network. In this study, we used the agent-based simulation method to reexamine the effectiveness of the traditional network market strategy under the presence of the local network where two incompatible technologies compete. We found that the strategy of growing an initial customer base is not effective under the presence of the local network. Our study also showed that targeting customers based on their technology Preference is not as effective as targeting customers within the same local network. As a result, the focus of a network market strategy should be directed to taking advantage of the customer network.

• 한국자동차공학회논문집
• /
• 제2권4호
• /
• pp.18-26
• /
• 1994

The buckling characteristics of I - shaped columns which are composed of thin web and equal upper/lower flange plates are generally classified into the local and global modes. In this paper, its local buckling problem has been formulated on the basis of the assumed buckling modes using the finite element method for beams and plates. The effects of local bucklings are studied for various size rations and end conditions of I-shaped columns. The calculated results are comparatively well consistent with values obtained from the existing studies. The global buckling characteristics calculated by the present method are in good agreement with the classical rigid web solution

• 한국전산구조공학회:학술대회논문집
• /
• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
• /
• pp.354-361
• /
• 2002

This paper propose section properties factor to generate stress history for fatigue analysis and safety inspection of steel bridge. A methodology is described for the computation of numerical stress histories in the steel truss bridge, caused by the vehicles using section properties factor. The global 3-D beam model of bridge is combined with the local shell model of selected details. Joint geometry is introduced by the local shell model. The global beam model takes the effects of joint rigidity and interaction of structural elements into account. Connection nodes in the global beam model correspond to the end cross-section centroids of the local shell model. Their displacements are interpreted as imposed deformations on the local shell model. The load cases fur the global model simulate the vertical unit force along the stringers. The load cases fer the local model are imposed unit deformations. Combining these, and applying vehicle loads, numerical stress histories are obtained. The method is illustrated by test load results of an existing bridge.

• 수완나부미
• /
• 제9권1호
• /
• pp.7-52
• /
• 2017

This paper analyzes the scholarly approaches to the problem of "local" vs. "cosmopolitan" in the context of the cultural transfers between South and Southeast Asia. Taking the "localization" paradigm advanced by Oliver Wolters as its pivot, it reviews the "externalist" and "autonomous" positions, and questions the hermeneutical validity of the fuzzy and self-explanatory category of "local." Having discussed the geo-environmental metaphors of "Monsoon Asia" and "Maritime Asia" as alternative paradigms to make justice to the complex dynamics of transregional interaction that shaped South and Southeast Asian societies, it briefly presents two case studies highlighting the tensions between the "local" and "cosmopolitan" approaches to the study of Old Javanese literature and Balinese Hinduism.

• 한국통신학회논문지
• /
• 제35권12A호
• /
• pp.1136-1144
• /
• 2010

본 논문에서는 IEEE 802.16m 시스템에서 HARQ 피드백 정보를 이용한 ARQ 프로토콜 (HARQ and ARQ interactions)을 사용할 때 HARQ 피드백 오류가 성능에 미치는 영향을 분석한다. 또한, HARQ 피드백 오류를 고려한 새로운 HARQ and ARQ interactions 기법을 제안한다. HARQ and ARQ interactions 기법은 ARQ 피드백 메시지를 대신하여 HARQ 피드백 정보를 사용하여 재전송 시간을 단축함으로써 시스템 throughput을 증가시킨다. 그러나 HARQ 피드백 메시지에 오류가 발생하는 경우 성능 열화가 발생 할 수 있다. 특히, HARQ 피드백 오류 중 Local NAK 오류가 발생 시 ARQ 블록의 유실로 인한 성능 열화가 심각하다. 본 논문에서는 HARQ Local NAK 오류를 고려하고 채널상태에 적응적으로 동작하는 HARQ and ARQ interactions 기법을 제안한다. 모의실험을 통해 제안한 기법 사용 시 throughput 및 delay 성능 향상을 확인하였고, 이를 정량적으로 분석하였다.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집E
• /
• pp.361-366
• /
• 2001

The present study describes a practical estimation procedure about the pantograph under several severe aerodynamic load conditions. As the operating speed of the Korean Train Express(KTX) reaches 350km/h, structural safety at various conditions should be examined at the design stage. In the present study, a compact and reliable procedure is developed to get aerodynamic loads on each part of the pantograph regarding the typhoon condition, the train/tunnel interaction, the train/train interaction and the side wind condition. In the estimation procedure, 3-dimensional steady and unsteady CFD simulation around the high speed train facilitates assigning the external local flow condition around the pantograph. The procedure is verified using the results of the low speed wind tunnel test at JARI and applied to 7 flow conditions and 4 operation configurations.

• 대한기계학회논문집B
• /
• 제30권9호
• /
• pp.891-897
• /
• 2006

The SRS method is applied to a turbulent flame with radiation/turbulence interaction to invert the temperature and concentration profile. The flame is conditioned as optically thin per each fluctuation length and the flame spectral intensity is measured for inversion. From inversion result, we find that SRS can successfully invert the coupled temperature/concentration fluctuation amplitudes. For two cases of experiments, inverted values are within approximately 1% over the full range of fluctuation amplitude. However, SRS cannot find the detailed local fluctuation parameters such as pattern and phase, etc. as far as they do not affect the resulting radiation intensity. Important available parameters are the mean temperature and the temperature fluctuation amplitude. The radiation/turbulence interaction effect is verified to play an important role in the radiation.

• 한국안전학회지
• /
• 제23권2호
• /
• pp.81-86
• /
• 2008

직사각형 폭발 챔버에서 전파하는 화염과 직사각형 장애물의 상관관계를 조사하기 위한 실험적 연구가 수행되었다. 챔버내에 10%, 20%및 30%의 blockage ratio를 가지는 3가지 직사각형 장애물들이 사용되었다. 전파하는 화염과 장애물의 상관관계를 조사하기 위해 고속카메라가 사용되었다. 고속카메라로 얻어진 화염 이미지로부터 장애물 주위의 국부 화염속도 및 그 화염속도의 확률밀도함수가 계산되었다. 실험결과, 전파하는 화염이 직사각형 장애물의 모서리와 상호작용할 때 국부 화염속도는 증가하였다. 그 증가속도는 장애물의 Blockage Ratio가 증가할 때 더욱 커지는 것으로 나타났다. 그러나, 평균화염속도는 Blockage Ratio에 큰 의존성을 가지지 않는 것으로 나타났다. 이 연구에서 사용된 작은 L(Lenlgth)/D(Diameter)비를 가지는 폭발 챔버내에서 전파하는 화염전면과 직사각형 장애물과의 상관관계는 L/D비가 큰 문헌에서 보고된 결과와 비교하면, Blockage Ratio에 따른 의존성은 작은 것으로 나타났다.

• 대한지리학회지
• /
• 제39권3호
• /
• pp.360-373
• /
• 2004

본 연구는 석유제품 유통기관의 판매권역을 설정하기 위한 방법론을 제시하고 설정된 판매권역별 특성을 살피고자 하였다. 이를 위해 공간적 상호작용 모델과 입지-배분모델을 적용하여 효과적으로 정유회사 하부의 지역본부 및 지사와 직영 주유소의 판매권역을 설정하는 방법론을 선정하고 판매권역별 특성을 고찰하는 것을 목적으로 한다. 정유회사의 지역본부 및 지사의 판매권역을 설정해 본 결과 경기지역본부와 같이 타 본부에 비해 유인력이 큰 공급지가 입지한 수도권의 경우 거리에 기초하여 수요지를 배분하는 입지-배분모델을 적용하고, 나머지 지역의 경우 수요지의 유출력과 공급지의 유인력을 현실적으로 반영할 수 있는 공간적 상호작용 모델을 적용하여 판매권역을 설정하는 것이 가장 합리적이었다. 또한 설정된 각 판매권역의 특성을 분석해 본 결과 판매권역 내에 포함되는 자동차대수와 인구수에 있어서 상당한 격차를 보이고 있었다. 이는 판매권역이 잠재적 수요를 기초로 하여 설정되므로, 휘발유 소비 수준의 격차가 이와 같은 판매권역간에 편차를 야기시키고 있다고 풀이할 수 있다.