SEDRIS 데이터 표현을 위한 3D 뷰어

李明苑 水原大學校 2004 論文集 Vol.22 No.-

SEDRIS(Synthetic Environment Data Representation and Interchange Specification) has been defined in the ISO JTC1 SC24 WG8 standardization group. This paper describes the development of a 3D viewer that can read, render, and transform all the kinds of 3D objects defined by the SEDRIS data representation. The viewer is composed of a tree view for the data structure, an attribute window for presenting the attributes, and a rendering view for playing and transforming the 3D representation of each object. Its feature is the point that it provides the method of describing all the attributes of the object including scalable unit information as well as the 3D data visualization.

자기유변유체를 이용한 Fused silica glass의 미세연마공정특성에 관한 연구

이정원,김동우,신영재,장호수,조명우 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

A new, commercially available polishing process called magnetorheological fluid polishing is used to fabrication optical glass and bio-chip. This polishing process guarantees high polishing quality by controlling the fluid density electrically. The applied material in experiments is fused silica glass. Fused silica glass is widely used in the optical and biochip field because of high degree of purity. For MR polishing experiments, MR fluid was composed with DI-water, carbonyl iron and nano slurry ceria. The wheel speed and electric current were chosen as the variables for analyzing the characteristics of MR polishing process. In results, the surface roughness according to the variation of wheel speed and electric current was analyzed.

IMT-2000 위성통신 시스템에서 폐쇄루프 전송 다이버시티 기법의 성능 분석

오관명,김학성,김산해,이경규,이원철,신요안 崇實大學校 2000 論文集 Vol.30 No.1

In this paper, we apply a close loop transmit diversity scheme to IMT-2000 satellite systems, and investigate the performance of the scheme in both ideal and more realistic situations. We verify that the performance of the closed loop transmit diversity scheme is quite sensitive to errors in feedback information. However, we also show that the number of quantization bits for feedback information does not significantly affect the system performance when considering the feedback of phase information only. In addition, 2-bit quantized system achieves the better performance than 4-bit quantized system in terms of slot error rate.

A Multimedia Information Service Platform

李明苑 水原大學校 1997 論文集 Vol.15 No.-

본 논문에서는 네트워크를 통해 멀티미디어 정보를 생성하고 검색할 수 있는 환경을 네트워크 사용자에게 제공하는 멀티미디어 정보서비스 플랫폼인 텔레서브(TeleServe) 개발에 대해 기술한다. 텔레서브는 서버, 클라이언트, 멀티미디어 정보 설계를 관리하며 네트워크 사용자가 요구하는 정보를 제공하는 역활을 한다. 클라이언트는 서버가 제공하는 정보를 통합하여 디스플레이해 주는 역할을 한다. 저작도구는 네트워크상에서 서비스 시나리오에 따라 모든 멀티미디어 정보를 생성해 준다. 이외에 본 논문에서는 텔레서브를 이용하여 개발한 서비스 응용인 텔레마켓팅시스템에 대해서도 기술한다.

MR Polsihing에서 알루미나 슬러리를 이용한 Si₃N₄세라믹스의 고정도 표면향상에 관한 연구

이정원,김동우,조명우,조원승,신영재 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

Silicon nitride Si₃N₄ is a leading ceramic for structural applications due to its superior properties at high temperature. It is very difficult-to-grind ceramics with high efficiency because of their high strength, hardness and brittleness. In this paper, ultra-precision surface for Si₃N₄ ceramic were using MR polishing method. MR Polishing experiment were using the magnetorheological fluid and Polishing abrasives are Al₃O₃. Polishing experiments were under various polishing conditions by changing a magnetic field force, wheel speed and polishing time. Polishing surfaces were observed analyzed by non-contact type 3-dimensional surface roughness measurement equipment. As a result, MR Polishing method can give excellent surface roughness, and surface roughness was obtained Ra=1nm.

MPEG-4 기반의 멀티미디어 동기화 모델

李明苑 水原大學校 2003 論文集 Vol.21 No.-

This paper describes a multimedia synchronization model based on the MPEG-4 (Moving Picture Expert Group) system, which integrates, manages and transfers multimedia objects such as audio, video, image, etc. BIFS(Binary Format for Scene) assigns the presentation and property of the object, and organizes a scene. The paper illustrates the methods of generating the scene description tree, of defining and adding the temporal relationship nodes to the original BIFS tree structure, and of managing them between objects during the playback of multimedia objects. It includes also the development of a MPEG-4 authoring system that users could define the temporal relationships of themselves, and let multimedia objects play.

와이어컷 방전에 의한 합금공구강과 초경합금의 북현상에 관한 연구

김원일,왕덕현,이재명 慶南大學校 附設 工業技術硏究所 1997 硏究論文集 Vol.14 No.2

와이어컷 방전가공에서 합금공구강과 초경합금을 대상으로 여러가지 방전인자가 북현상에 미치는 영향을 관찰하였다. 북현상은 방전극간전압과 방전주기가 작고, 두께가 얇고 와이어장력이 크며, 가공횟수를 많이 할수록 줄어든다. 두께 60mm초경합금을 보통의 조건으로 가공하면 전해작용에 의해 결합제인 코발트가 용출되어 주성분인 탄화텅스텐이 탈락되어 북현상이 커지므로 전도도를 낮게 해야한다. From the experimental study of wire-cut Electric Discharge Machining for alloyed steel and tungsten carbide, the characteristics such as hand drum form has been observed and evaluated for various conditions. Hand drum form can be improved when gap voltage and spark cycle become smaller, their thickness become thinner, wire tension become larger and no. of cuttings is done so many times. When wire-cut 60mm thickness tungsten carbide in normal condition. Hand drum form becomes larger due to the low conductivity inducing cobalt composite rising by electrolysis.

가상 물체의 물리적 속성 정의

李明苑 수원대학교 2006 論文集 Vol.24 No.-

현재의 컴퓨터 그래픽스 기술은 컴퓨터 화면에 가상물체 표현시 정규화된 좌표치로 물체를 나타낸다. 따라서 컴퓨터 화면에 나타낸 가상물체의 경우에는 별도의 텍스트 정보가 없으면 그 물체의 실제 크기 등을 포함한 물리적 속성을 알아낼 방법이 없다. 또한, 두 물체의 크기의 차가 매우 클 경우에는 컴퓨터 해상도의 제한으로 해서 두 물체를 동시에 화면에 그려낼 수도 없다. 이와 같은 문제를 해결하기 위하여 본 논문에서는 웹 가상환경에서 물리 속성 중에서 실제 길이를 정의 하고 구현하는 방법을 제안한다. 이를 위해 실세계에서 길이의 단위로서 이용되는 미터, 센티미터, 밀리미터 등의 길이 측정 단위를 나타내기 위해 LOLD(Level of Length Detail)을 정의한다. 그리고, 이러한 개념을 포함한 물체를 화면에 디스플레이하고 조작할 수 있도록 하는 확장 X3D 브라우저 개발에 대해서도 소개한다.

인산용액의 농도 및 적용시간 차이에 따른 상아질 표면의 형태적 변화

김명수,온영석,이광원,손호현 大韓齒科保存學會 1998 Restorative Dentistry & Endodontics Vol.23 No.1

The depth and patterns of demineralization according to the difference in concentration and application time of phosphoric acid were observed through the transmission electron microscope, and shear bond strengths to the acid-conditioned dentin were then measured and compared with the TEM results. To investigate the influence of polymer addition into the phosphoric acid and the effect of difference in concentration and application time of the acid, the specimens were randomly divided into 9 groups. Among the specimens, the exposed dentin surfaces were acid-conditioned with 10% polymer-thickened phosphoric acid(All Bond 2, Bisco, U.S.A.) and aqueous 10%, 20%, 30%, 40% phosphoric acid for 20 seconds, The rest of the specimens were acid-conditioned with 10% phosphoric acid for 15s, 30s, 60s, 120s respectively. The specimens were immersed in 4% glutaraldehyde in 0.1M sodium cacodylate buffer and postfixed with 1% osmium tetroxide without decalcification and then observed under a JEOL Transmission Electron Microscope(JEM 1200 EXⅡ,Japan). After the specimens were acid-conditioned as the above, primer and adhesive resin were applied to blot-dried dentin and shear bond strengths were then measured and analysed. The results were as follows : 1. The intertubular demineralization depth of 4.0-5.0㎛ in 10% polymer-thickened phosphoric acid gels was similar or slightly deeper than that of 4.0-4.5㎛ in aqueous 10% phosphoric acid solution. 2. The intertubular demineralization depth of aqueous 20%, 30% and 40% phosphoric acid solution was 6.5-7.0㎛, 6.5-7.5㎛ and 9.0-15.0㎛ respectively. It showed that the depth of dentin demineralization is partly related to the concentration of phosphoric acid solution. 3. The intertubular demineralization depth of aqueous 10% phosphoric acid solution in application time for 15s, 30s, 60s and 120s was 2.5-3.0㎛, 4.0-6.0㎛, 6.5-7.0㎛ and 8.5-14.0㎛ respectively. It showed that the depth of dentin demineralization is directly related tothe application time of phosphoric acid solution. 4. The partially demineralized dentin layer between demineralized collagen layer and unaffected dentin was showed to a width of 0.5-1.0㎛ in lower concentration groups treated with aqueous 10% phosphoric acid for 20s, 60s, 120s and 20% phosphoric acid for 20s. 5. The demineralization effect at the border of intertubular-peritubular junction was less evident than that in the peritubular and intertubular dentin. The collagen fibers in the intertubular dentin had a random orientation, whereas those that lined the tubules were circumferentially aligned. The cross-linkage of dentinal collagen in demineralized collagen layer was clearly seen. 6. A statistically significant difference of bond strengths according to the difference in phosphoric acid concentration did not exist among the groups treated with 10%, 20%, 30% and 40% acid solution (P>0.05). However, bond strengths to the treated dentin with 10% phosphoric acid solution for 30s were significantly higher than that for 120s (P<0.05).

기업이 인터넷을 성공적으로 활용하는데 요구되는 요인 분석과 인터넷 활용 전환 전략

권원일,박명철,김문구 한국경영과학회 2000 經營 科學 Vol.17 No.3

The needs of strategic approach toward the usage of the internet in corporate context are increasingly important as digital economy changes the way of doing business. However, companies are not easily taking the opportunity since the strategic use of the internet is difficult because of the conflicts in distribution, business process, organization structure, etc. The internet strategy applicable to companies in a generic context is proposed by identifying the CSFs(Critical Success Factors) in exploiting the potential of the internet. CSFs are derived by the previous study and case analysis, from which two most important factors are chosen based on a survey. In the survey, the ranking of the significance of the 8 CSFs from the 25 cases is questioned to the internet experts. Then a 2×2 matrix is designed to find the optimal area for a company to be successful in the internet usage. The strategy suggested here appears to be the shifting strategy in order to be in the optimal area in using the internet strategically.