• Korean Journal of Optics and Photonics
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• v.16 no.1
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• pp.71-78
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• 2005

A null lens system of autostigmatic type, consisting of two mirrors, is designed for testing a large aspherical mirror. The system is theoretically analyzed to determine the limitation of measurement accuracy according to the manufacturing and alignment errors. We confirmed that irregularity of the null lens surface is the principal factor among tolerances in limiting measurement accuracy. Consequently, we can predict that measurement accuracy will be from 5λ/100 to 4λ/1000 according to the amount of this irregularity. That is, we can present the limitation of possible measurement accuracy with actual alignment and manufacturing errors.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.36 no.1
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• pp.37-48
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• 2020

Logistics centers, distribution centers, or warehouse facilities increasingly dominate urban and suburban landscapes, their enormous but blank, repetitive facades completely overshadowing adjacent buildings. Mostly ignored by architects, this new building type symbolically represents the arrival of post-anthropocene, or post-urbicene era of architecture, in which an increasing portion of our built environment will not be intended for human occupancy, but rather for use by machines and artificial intelligence. As a new wave of logistics centers are becoming more automated, and more supersized, it is important to deepen architects' understanding of the organizational logic and programming factors that inform the overall design decisions for these facilities. With a particular focus on three case studies--Coupang, E-Mart, and Amazon Fulfillment Centers, this research examines the current trends in automation and expansion of logistics centers, and offers an analysis and forecast for future facilities in South Korea.

• Journal of the Korea Institute of Building Construction
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• v.21 no.6
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• pp.617-627
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• 2021

In this study, a numerical analysis using a three-dimensional numerical simulation was performed to assess the applicability of foundation reinforcing method using load transfer apparatus which can be used in the remodeling of deteriorated structures. The numerical model was validated through comparison with the real scale experimental results, and then a parametric study was performed to investigate the effect of friction coefficient of load transfer apparatus and axial stiffness of pile on the performance of foundation reinforcing method. It was confirmed that the foundation reinforcing method considered in this study can efficiently control the load applied to an existing foundation.

• Proceedings of the Korea Information Processing Society Conference
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• 2010.11a
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• pp.818-819
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• 2010

고층빌딩, 지하역사와 같은 대형 복합건물은 건물 자체의 복합도 증가와 더불어 이에 따른 위험요소(hazard)의 증가를 가져오고 위험상황에 대처해야 할 소방관들의 대응기술 및 훈련도 고도화되어야 한다. 실제 화재현장, 특히 대형 복합건물에 대한 훈련은 비용, 시간뿐만 아니라 소방관 안전 확보라는 차원에서 불가능하며 반복적인 훈련이나 그 평가가 어렵다는 점에서 가상환경을 이용한 훈련 시스템이 필요하다. 본 논문에서는 복합건물에 대한 소방관 팀 훈련 시스템 구현을 위한 가상환경의 설계 및 구현을 소개하고자 한다. 가상환경은 소방관의 훈련 및 평가, 팀 단위훈련을 제공하고 현실감 있는 훈련을 위하여 가상현실, 증강현실, 물리체험 모듈을 이용한 사용자 인터페이스를 제공한다. 가상환경 구축을 위하여 대상 건축물에 대한 3 차원 모델을 구축하고 도출된 발생 가능한 화재 시나리오에 대한 수치적 모델링을 수행하고 그 결과를 가상환경 및 훈련 시나리오에 반영하였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.453-454
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• 2011

에너지 플랜트, 화학공장 등 대형 기계설비의 복잡도 증가는 그에 따른 위험요소 복잡도를 증가시키고 있다. 대형 기계설비에 대한 위험 관리와 시스템 신뢰도 향상을 위해서는 위험도 기반의 안전 설계/해석, 상태 감시 및 진단을 이용한 설비 모니터링, 인적 신뢰도 향상이 요구되며 설계 단계에서부터 운영 및 유지보수 단계까지의 시스템 생애주기 전반에 걸친 지속적인 활동을 필요로 한다. 인적 신뢰도를 향상시키기 위해서는 설비 운영자가 응급 또는 이상상황에 대처할 수 있는 능력 즉, 안전사고 대응 능력 확보가 필수적이다. 대상 설비에 대한 실제 훈련은 시간, 비용, 훈련자의 안전 확보가 어렵고 반복적인 훈련 및 평가가 어렵기 때문에 가상 환경을 이용한 안전대응 훈련 플랫폼을 설계하였다. 훈련자에게 몰입형 가상 환경을 제공하기 위하여 가상현실 및 안전사고 시뮬레이션 기술을 이용하였으며 이를 통하여 훈련자의 안전을 유지하면서 안전대응 능력을 향상시킬 수 있다.

• 전자공학회논문지 IE
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• v.48 no.4
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• pp.69-77
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• 2011

Recently, the public sector information projects have bebn larger in size, sophisticated, and diversified, which make the performance management model be studied continuously. According to the research and understanding on this, there are discontents resulted from poor requirements managements, schedule delays, budget overruns, failure to achieve expected goals, although there are increase the scale of projects and the number of information systems than ever before. it makes the requirement for the plan to manage significant risk factors systematically. So in this study, we will understand the risks which have been recognized by professionals and managers in public sector projects for enhancing the success rate. And the surveys will be conducted for the risk factors in each fields by gathering the opinions of the hands on workers in public sector project support team such as S company, L company. Finally, the correlation index between the risks and the other project fields would be clear by this survey.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.13 no.2
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• pp.189-196
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• 2000

The objective of this paper is to propose an analysis technique to predict the behavior of PC wall structures subjected to cyclic load. While PC wall panel is idealized by finite elements, the joints at which PC walls are connected each other are idealized by nonlinear spring elements. Axial and shear spring elements are developed for simulating shear, compression and tension behaviors of joints. The strength and stiffness of each spring elements we presented from the previous research results and incorporated into the computer program of DRAIN-2DX. The proposed analysis technique is evaluated by analyzing specimens previously tested and comparing with those. On the strength, stiffness, energy dissipation and lateral drift, analytical results show good agreements with test results. This means the proposed technique is effective to predict the response of the PC wall structures.

• Journal of Distribution Science
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• v.6 no.1
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• pp.117-128
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• 2008

The purpose of the research is to furnish basic data for efficient and effective marketing by examining the correlation how a certain element effects on customer's selection behavior, when they choose private label branded clothes at the store of giant discount store like E-.mart, Home-plus, Lotte-mart and 2001 outlet. We come to the following conclusions through such procedures; What we found on this study is that main factors of decision related purchasing garment of private brand in giant discount store is based on the sales price, quality of products and needs of customer's using. Further to this, in terms of choice activity in private brand clothes, we realized the price value is depend on the resonable price with the items because nowadays most customers can be compare to other discount store around their shopping place including trend of garment and quality of products. The order of the general inclination in selection behavior of private branded garment in giant discount store is as follows; Sales price > style & trend > quality of product and substantial convenience > display and prompt buying. Judging from the conclusion of the research we noted that customer's satisfaction comes from their target price to supply substantial needs and in terms of styling of clothes should be considered current trendy compared to national brand as well.

• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.5-16
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• 2015

In the long span bridge construction, construction cost portion of large scale marine foundation is about 40% (KICTEP, 2007). In this study, designs for deep water depth large composite foundation of a super long span cable-stayed girder bridge of prototype were performed by three design methods (ASD, LRFD, Eurocode) and the behaviors of a large diameter drilled shaft were analyzed and the 3D numerical analysis was performed. As a result, the soft rock socket lengths in allowable stress design estimation method were the longest. The soft rock socket lengths estimated by the design approach 2 among Eurocode and the LRFD were similar. The longer the socket length socketed in the soft rock was, the smaller the axial force acting on a large-diameter drilled shaft head was and the smaller the settlement of drilled shaft was.

• Proceedings of KOSOMES biannual meeting
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• 2004.05b
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• pp.107-112
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• 2004

In order to improve the safety r! ship berthing and the efficiency r! berth operation in the harbour, the berthing energy acting on a ship in berthing maneuver need to be estimated properly. The berthing energy is used as one q the criteria to determine the maximum permissible load of fender as well as important factors to establish the berthing speed and the required power r! tug-beat for pilot and ship operator. In this study, some problems r! present the method of berthing energy are discussed on the basis of the hydrodynamic aspects. Then, series calculations of berthing energy are carried out considering the effect of water depth on added mass and the ship shape for container series from 1,600TEU to 12,000TEU.