• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.5-8
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• 2003

This paper presents a methodology to be able to select an appropriate RP system that suits the end use of a part. Evaluation factors used in process selection include major attributes such as accuracy, roughness, strength, elongation, part cost and build time that greatly affect the performance of RP systems. Crisp values such as accuracy and surface roughness are obtained with a new test part developed. The test part is designed with conjoint analysis to reflect users' preference. The part cost and build time that have approximate ranges due to cost and many variable parameters are presented by linguistic values that can be described with triangular fuzzy numbers. Based on the evaluation values obtained, an appropriate RP process for a specific part application is selected by using the modified TOPSIS(Technique of Order Preference by Similarity to Ideal Solution) method. It uses crisp data as well as linguistic variables, and each weight on the alternatives is assigned by using pair-wise comparison matrix. The ranking order helps the decision making of the selection of RP systems.

• 한국생산제조학회지
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• 제24권2호
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• pp.148-154
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• 2015

Computer aided process planning (CAPP) keeps an important role between the design and manufacturing engineering processes. A CAPP system is a digital link between a computer aided design (CAD) model and manufacturing instructions. CAPP have been researched and applied in manufacturing filed, however, one manufacturing area where CAPP has not been extensively researched is rapid prototyping (RP). RP is a technique for creating directly a three dimensional CAD data into a physical prototype. RP enables to build physical models automatically and to use to reduce the time for the product development cycle as well as to improve the final quality of the designed product. Three-dimensional (3D) printing is one kind of RP that creates three-dimensional objects from CAD models. The paper presents a computer aided process planning system for printing medical products. 3D printing has been used to solve complex medical problems such as surgical instruments, bioengineered products, medical implants, and surgical guides.

• Clinical Endoscopy
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• 제55권1호
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• pp.22-32
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• 2022

Radiotherapy (RT) is a treatment modality that uses high-energy rays or radioactive agents to generate ionizing radiation against rapidly dividing cells. The main objective of using radiation in cancer therapy is to impair or halt the division of the tumor cells. Over the past few decades, advancements in technology, the introduction of newer methods of RT, and a better understanding of the pathophysiology of cancers have enabled physicians to deliver doses of radiation that match the exact dimensions of the tumor for greater efficacy, with minimal exposure of the surrounding tissues. However, RT has numerous complications, the most common being radiation proctitis (RP). It is characterized by damage to the rectal epithelium by secondary ionizing radiation. Based on the onset of signs and symptoms, post-radiotherapy RP can be classified as acute or chronic, each with varying levels of severity and complication rates. The treatment options available for RP are limited, with most of the data on treatment available from case reports or small studies. Here, we describe the types of RT used in modern-day medicine and radiation-mediated tissue injury. We have primarily focused on the classification, epidemiology, pathogenesis, clinical features, treatment strategies, complications, and prognosis of RP.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.30-35
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• 2002

Nowadays, as the development period of new products becomes shorter and consumer's requirement is more various, the importance of Rapid Prototyping Technology has been rapidly increased. Rapid Prototyping makes prototypes or frictional parts directly using the 3D CAD data. But RP machines can make prototypes in limit size. For making large size prototype, we slice solid which is made of STL file, and then glue sliced solid. And if contact area of part is small, union solid will be easily destroyed for going down of adhesion. So we need to expand contact area, 1 suggest making a section into stair shape. This paper is concerned with slicing solid on STL file and improving on adhesion.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 춘계학술대회 논문집
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• pp.587-591
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• 1996

Usually triangular patches are used to transfer geometric shape in Rpaid Prototyping CAM system. STL, a list of triangles, is de facto in RP industry. Because STL has no topology data, it can cause errornous results. So, STL should be verified before using. After adding support structures to anchor the part to the platform and to prevent sagging or distortion, slicing and layer by layer manufacturing process are done. But triangular patch is surface model and cannot provide dufficient information on geometry in the above processes. So, geometric modeling is necessary in verifying STL, adding support structures, and slicing. It is natural that triangle based modeling is the best when traingular patches are used as input. Considering support structures, solid and faces coexist in RP process. Therefore non-manifold modeler is required. In this study, triangle based non-manifold geometric modeling is proposed for RP system consitent with STL input.

• 대한교통학회지
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• 제18권6호
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• pp.63-75
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• 2000

SP 데이터는 데이터 수집의 효율이 RP 데이터 보다 높고 장래의 교통 시스템의 조건이나 속성에 대한 응답자들의 태도를 조사 할 수 있다는 점에서 많이 사용되고 있으나 SP 데이터는 주요하게 두 가지 편위를 가지고 있는데 SP 설문조사시에 발생하는 응답편위와 SP 패널조사시에 발생하는 누락편위이다. 이러한 SP 데이터의 편위가 수정되지 않으면 장래의 잘못된 교통수요예측을 유발할 수 있다. 따라서 본 연구에서는 이러한 SP 모델의 편위와 상태의존을 고려한 모델을 구축하기 위하여 6개의 횡단면 모델과 동적모델을 제안하였다. 횡단면 모델 중 RP데이터의 선택결과를 고려한 모델을 이용하여 SP모델의 편위를 보완할 수 있는 모델을 구축할 수 있었으며 동적모델의 경우에 패널데이터의 상태의존도를 지수함수로 가정하여 상태의존도를 고려한 동적모델을 구축하였다. 또한 패널조사시에 필연적으로 발생하는 누락데이터에 의한 누락편위를 모델에 고려하기 위하여 WESML방법을 적용하여 모델을 구축하였으며 그 결과 상태의존도를 보다 세밀하게 제어함으로서 모델의 설명력을 개선시키고 향후 SP 패널데이터를 이용한 동적모델의 적용성을 높일 수 있음을 알 수 있었다. 본 연구에서는 모델의 유용성을 검토하기 위하여 전주시의 외각 지역인 호남제일문 방향에서 도심으로 접근하는 3개의 주경로(천변로, 기린로, 팔달로)에 대한 패널조사 자료를 바탕으로 모델을 구축하였다.

• 한국컴퓨터정보학회논문지
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• 제25권3호
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• pp.81-88
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• 2020

Renewable Portfolio Standard(이하, RPS)는 오래 전부터 시행 중인 친환경 에너지 사업이다. 현재의 RPS는 다양한 기관에서 접근하는 사업임에도 불구하고 중앙집중화의 시스템으로 구성되어 있다. 이는 사용자 입장에서 데이터 접근의 불투명성이 존재한다. 그리고 데이터베이스 또한 각자의 기관에서 필요한 정보를 각자가 소유하고 있다. 그렇기에 시간의 경과에 따라 데이터양이 늘어남으로 더욱더 통합적인 관리가 필요해졌다. 또한, 각자의 기관에서 유지 중인 서버가 공격을 당할 시에 RPS 업무의 중지라는 위험이 존재한다. 이와 같은 문제점을 해소하고자 본 논문은 블록체인을 이용한 RPS를 제안한다. 컨소시엄 방식의 블록체인을 이용하여 블록 데이터 안에 Renewable Energy Certificate(이하, REC) 데이터를 삽입하여 모든 기관이 동일한 데이터를 소지하고 있고, 해당 블록들의 검증을 통해서 거래가 이루어지므로 투명성과 보안의 문제점 해소가 가능하다. 그리고 어느 하나의 기관이 외부적인 공격으로 인해 서버의 작동이 중단되는 경우에도 다른 기관이 해당 역할을 대체할 수 있다. 본 논문은 이더리움 네트워크를 통해 블록 안에 데이터를 넣는 과정을 실험하였으며, 이를 통해 RPS에 블록체인 기법을 도입하는 가능성을 제시하였다.

• 한국컴퓨터정보학회논문지
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• 제6권2호
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• pp.116-122
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• 2001

기존의 멀티캐스트 보안 프로토콜은 DVMRP, CBT와 같이 비교적 규모가 큰 라우팅 프로토콜에 적합하도록 설계되어 있어서 사용자가 비교적 적고 호스트들간의 지역적인거리가 멀고 최단경로 라우팅 특성을 가지는 PIM-SM(Protocol Independent Multicast-Sparse Mode) 라우팅 프로토콜을 지원하는데 무리가 있다. 본 연구에서는 모든사용자간의 가입/탈퇴시 또는 서비스 사용 중에 사용자의 정당한 서비스 보호를 위해 서브그룹을 RP단위로 나누고, 송신자만의 비밀키를 따로 관리하는 보안 구조를 설계하였다. 그결과 데이터 전송 시 그룹 키에 의한 자료 변환 작업이 불필요하여 키 분배시간이 단축되고, 다른 보안 구조에 비해 구조가 보다 간단해졌다.

• 한국CDE학회논문집
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• 제2권1호
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• pp.35-43
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• 1997

Concurrent Engineering is one of the methods which are used for the rapid product development. One of the important features in Concurrent Egineering is that the development process is to be parallel and the organization should be cross-functional. In order that the process be parallel and that the organization be cross-functional, an integrated information system such as PDM (Product Data Management) is required. Although the integrated data base is constructed, it could be meaningless if the application softwares were not inter-operable. This study shows an example of intergrated information system from three-dimensional product design to mold design and tooling for the development of Deflection Yoke(DY) which is one of the important parts of Cathode Ray Tube(CRT). A three-dimensional product design software, which is based on a commercial code, has been developed by ourselves. Selective Laser Sintering(SLS), which is one of the rapid prototyping techniques, has been used in this study. Mold design has been done by the three-dimensional way. A newly developed method of mold tooling, which is called Quick Die Manufacturing(QDM), has been introduced.

• 대한기계학회논문집A
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• 제27권4호
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• pp.485-490
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• 2003

RP(Rapid Prototyping) has been used in the various industrial applications. This paper presents the optimization techniques fur fabricated 3D model design using RP machine for the medical field. Once the original brain model data are obtained from 2D slices of MRI/CT machine, the data can be modeled as an optimal ellipse. The objective of this study includes optimization of fabrication time and surface roughness using the adaptive slicing method. It can reduce fabrication time without losing surface roughness quality by accumulating the slices with variable thickness. According to the parameter tuning and synthesis of its effect, more suitable parameter values can be obtained by enhanced 3D brain model fabrication. Therefore, accurate 3D brain model fabricated by RP machine can enable a surgeon to perform pre-operation. to make a decision for the operation sequence and to perceive the 3D positions in prototype, before delicate operation of actual surgery.