• 대한안전경영과학회지
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• 제9권4호
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• pp.149-154
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• 2007

The LNG carriers have been propelled by steam turbines and the LNG boil-off(BOG) has been used as fuel or vented. However, as the alternative propulsion systems such as diesel engines are being equipped on the LNG carriers for better fuel efficiency, a need for the LNG BOG re-liquefaction system that liquefies the BOG and sends the liquid BOG back to the LNG cargo has arisen in recent years. This study investigates the design of the BOG re-liquefaction system based on the reverse Brayton refrigeration cycle. The thermodynamic and heat exchanger analysis are carried out and the limitations to the system performance are discussed.

• Structural Engineering and Mechanics
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• 제89권5호
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• pp.467-477
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• 2024

Manufacturing industries, now-a-days, focus mostly on redesigning of the products for reducing cost and lead-time via detailed analysis of its composition and constructional design regarded as the Reverse Engineering (RE) process that involves the acquisition of relevant data of the original product, analysis for its functional use and finally, reproduction of the design for improving the functionality. In the present work, a new model based on optimization at different steps of RE, is proposed to redesign a structural component, which is subjected to severe tensile stress while in service. The component under study is an accessory namely, hitch bracket, attached to the rear axle of a tractor to connect it to the plough. The methodology includes building of a 3D Computer Aided Design (CAD) model from the scanned data of the existing component with the help of 3D scanner. Computer Aided Engineering (CAE) analysis is carried out on the CAD model with existing load conditions by Finite Element Analysis (FEA). Topological optimization is carried out giving rise to a modified/optimized design of the component. It is observed that the performance of the modified component improves significantly with simultaneous weight reduction without affecting its functional use and the manufacturing process setup.

• 한국인터넷방송통신학회논문지
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• 제21권2호
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• pp.79-88
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• 2021

과학용 소프트웨어는 전문가 수준의 깊이있는 도메인 지식 요구 등과 같이 고유한 특성들로 인하여 전통적인 응용소프트웨어와는 다른 개발 프로세스가 요구된다. 본 연구에서 우리는 과학용 소프트웨어 개발을 위하여 RE(Reverse Engineering)과 TDD(Test-Driven Development)에 기반한 V&V 개발 프로세스를 제안하였다. 또한 실제 프로젝트에 가상 시나리오를 구성하고 적용하여 절차를 검증하고 정교화 하였다. 과학용 소프트웨어 개발을 목적으로 제안된 본 연구의 개발 프로세스는 고품질, 고 신뢰성을 제공할 수 있는 소프트웨어 개발 및 적용에 기여할 것이다. 또한 본 연구는 과학용 소프트웨어 개발 및 연구의 저변 확산의 계기가 될 것으로 기대된다.

• 전기전자학회논문지
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• 제23권3호
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• pp.934-940
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• 2019

본 논문에서는 낮은 비용과 높은 신뢰성 그리고 데이터율이 좋은 비-코히어런트 카오스 통신을 위한 역방향 차동 카오스 편이변조(Reverse Differential Chaos Shift Keying, RE-DCSK) 시스템을 제안한다. RE-DCSK의 참조 신호들은 기존 차동 카오스 편이 변조 방식(DCSK)에서처럼 첫 번째 슬롯에서 전송하며 두 번째 슬롯에서는 시간 반전 블록이 카오스 신호의 자기상관 관계를 강화시키고 두 신호의 직교성을 이용하여 정보신호의 역할을 한다. RE-DCSK는 시스템의 복잡성에 따르는 어떠한 추가 비용도 없이 DCSK와 비교했을 때 상대적으로 두 배의 전송률을 가능하게 하고 통신의 보안 성능도 역시 향상시킨다. 그 효율성을 입증하기 위해 도출한 BER 표현식을 기반으로 레일리 페이딩 채널과 부가 백색 가우시안잡음(AWGN) 채널을 통하여 분석한다. 제안한 시스템의 BER 성능은 AWGN 채널을 사용한 상호지연 편이변조 방식(CDSK)와 DCSK 시스템과 비교하였을 경우 성능이 향상된다.

• 대한토목학회논문집
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• 제42권6호
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• pp.869-877
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• 2022

본 연구의 목적은 주택연금 중도해지자의 재가입 소요기간 결정요인을 실증분석하는 것이다. 실증분석을 위하여 주택연금을 운용 중인 한국주택금융공사 DB에서 2007년 7월부터 2021년 6월까지 중도해지 후 재가입자에 관한 정보를 추출하였다. 순서형로짓모형을 통한 실증분석 결과, 첫째, 가입자 개인 특성 중 연령대 변동, 부부에서 독신으로 변동, 독신 유지, 최초가입 유지기간 변수들이 통계적으로 유의하였고, 이 중 최초가입 유지기간이 재가입 소요기간을 단축시키는 요인으로 추정되었다. 둘째, 담보주택 특성 중 주택가격 변동과 소유형태 변동 변수들이 통계적으로 유의하였고, 이 중 소유형태 변동이 재가입 소요기간을 단축시키는 요인으로 추정되었다. 셋째, 계약 특성 중 지급방식 변동과 지급유형 변동변수들이 통계적으로 유의하였고, 이 두 변수들은 모두 재가입 소요기간을 증가시키는 요인으로 추정되었다. 실증분석 결과를 바탕으로 재가입 소요기간을 증가시키는 요인에 초점을 맞춘 제도개선을 통하여 중도해지자의 재가입을 유도하는 것과 동시에 소요기간을 단축시키는 것이 필요할 것으로 사료된다.

• 한국CDE학회논문집
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• 제3권1호
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• pp.22-30
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• 1998

The deflection yoke (DY) controls the direction of the electron beam that falls on the screen of the television monitor. Its quality depends on the shape and density of coils wound around the DY coil separator. Winding frames are used to make these coils, and therefore, their shapes are essential in making quality coils. A reverse engineering(RE) is applied to create the 3D model of the winding frame. It considerably shortens the design verification time and shows the level of accuracy that is feasible in the production mode. The paper explains each step of the reverse engineering process in detail.

• 한국정밀공학회지
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• 제21권6호
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• pp.188-196
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• 2004

The objective of this paper is to propose a new technology of the orthopaedic surgery using the combination of reverse engineering (RE) based on CT data and rapid prototyping (RP). The proposed technology utilizes symmetrical characteristics of the human body and capability of the combination of RE and RP, which rapidly manufactures three-dimensional parts from CT data. The original .stl data of injured extents are generated from the mirror transformation of .stl file fur uninjured extents. The physical shape before injuring is manufactured from RP using the original .stl data. Subsequently, pre-operative planning, such as a selection of proper implants, preforming of the implant, a decision of fixation locations and an insert position for the implant, an estimation of the invasive size, and pre-education of operators are performed using the physical shape. In order to examine the applicability and the efficiency of the proposed surgical technology, various case studies, such as a distal tibia commented fracture, a proximal tibia plateau fracture and an iliac wing fracture of pelvis, are carried out. From the results of case studies, it has been shown that the proposed technology is an effective surgical tool of the orthopaedic surgery reducing the operational time, the operational cost, the radiation exposure of the patient and operators, and morbidity. In addition, the proposed technology could improve the accuracy of operation and the speed of rehabilitation.

• 제어로봇시스템학회논문지
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• 제9권10호
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• pp.836-843
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• 2003

The automatic train control (ATC) system development project for the Automated Guideway Transit (AGT) system has high technical risk because the system is unmanned train control system using wireless technology which was unprecedented in train control industry of Korea. To overcome the technical risk during concept design phase of the ATC system development project, the integrated product team(IPT) carried out a reverse and reengineering process using a systems engineering design model. The generic systems engineering process is incorporated in the both reverse and reengineering process. As a result of the systems engineering effort, the IPT has built top layer systems engineering design model of the ATC subsystem. The purpose of this paper is to deliver the reverse and reengineering process which was used to develop the systems engineering design model of ATC system using a computer aided systems engineering tool. This study also shows that the model based reverse and reengineering process can reduce the technical risk by identifying the differences of requirement, functional and physical architecture between a reference system and a target system.

• 한국정밀공학회지
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• 제17권10호
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• pp.17-25
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• 2000

• Journal of Mechanical Science and Technology
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• 제19권12호
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• pp.2213-2223
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• 2005

In order to reconstruct a full 3D human model in reverse engineering (RE), a 3D scanner needs to be placed arbitrarily around the target model to capture all part of the scanned surface. Then, acquired multiple scans must be registered and merged since each scanned data set taken from different position is just given in its own local co-ordinate system. The goal of the registration is to create a single model by aligning all individual scans. It usually consists of two sub-steps: rough and fine registration. The fine registration process can only be performed after an initial position is approximated through the rough registration. Hence an automated rough registration process is crucial to realize a completely automatic RE system. In this paper an automated rough registration method for aligning multiple scans of complex human face is presented. The proposed method automatically aligns the meshes of different scans with the information of features that are extracted from the estimated principal curvatures of triangular meshes of the human face. Then the roughly aligned scanned data sets are further precisely enhanced with a fine registration step with the recently popular Iterative Closest Point (ICP) algorithm. Some typical examples are presented and discussed to validate the proposed system.