DSP 보드를 이용한 OFDM 모뎀 구현

오정훈,신인식,김영수,서덕영,김진상 경희-다반 ASIC 설계교육센터 2005 경희-다반 ASIC센터 논문집 Vol.6 No.-

본 논문에서는 무선 멀티미디어 서비스를 위해 요구되는 고속의 데이터 전송에 적하한 Orthogonal frequency Division Multiplexing(OFDM) 모뎀을 Texas Instrument(TI)사의 범용 DSP 프로세서인 TMS320C6701을 기반으로 한 PCI/C6701 보드를 이용해서 소프트웨어로 설계하였다. 모듈은 크게 보드를 제어할 수 있는 타겟 프로그램과 호스트 프로그램으로 구성되며, 타겟 프로그렘은 IEEE 802.11a Wireless LAN 규격 시스템으로 이루어지고, 호스트 프로그램은 타겟 프로그램의 다운로드와 BSP 프로세서에 의해 처리된 데이터의 디스플레이 또는 저장으로 이루어진다.

이종접합재 접합 계면근방 균열의 응력 및 파괴특성

오정국,차용훈,오환섭,박준건,박경식 朝鮮大學校 機械技術硏究所 1998 機械技術硏究 Vol.1 No.1

현재까지 이종마찰압접재의 강도측정은 실험 (7)-(15)에 의해 구해져 왔다. 하지만 최근 이종마찰압접재의 효율성을 인정하여 여러 실용 부품에 응용하려는 연구가 한창 진행중이다. 이종마찰압접재에 대한 저자들(1)-(6)의 기초실험결과 일반적인 단종재와는 상이한 파괴거동(3)이 관찰되었고, 파괴역학적인 관점에서 정성적인 data 확보가 필요하게 되었다. 따라서 본 연구에서는 인장시험시 이종마찰압접재의 접합강도와 미소균열들에 의한 파괴거동을 파괴역학적 관점에서 해석적으로 고찰하여 보고자 경계요소법(BEM ; Boundary Element Method)을 이용하여 접합계면을 포함하는 접합부를 중심으로 계면상의 응력분포와 계면의 중앙에 결함이 균열로써 존재하는 경우의 응력분포와 인장시험시 열영향부에서 관찰된 균열의 모델링을 통한 균열선단에서의 응력해석을 행하였고, 그 결과 얻어진 중요한 내용을 요약하면 다음과 같다. 계면의 중앙에 균열이 존재하는 접합계면의 표면부에서 응력의 특이성이 발생하며 탄성계수의 비가 증가할수록 특이성이 증가함이 관찰되었다. 탄성계수의 비가 일정한 경우 균열의 크기가 변화하여도 계면의 표면부에서 발생하는 특이성은 거의 같은 값을 갖게 되며, 탄성계수의 비가 증가할수록 표면부의 응력 특이성의 크기는 증가한다. 이종마찰압접재의 인장시험시 관찰된 균열을 모델링 하여 해석한 결과 최대 응력 기준으로 살펴볼 때 인접한 균열선단에서의 응력분포는 균열을 합체시키는 방향으로 작용함을 알 수 있다. In this study stress distribution on the interface and stress near tip of the sub-interface crack in the dissimilar friction welded material is analyzed by using of BEM( Boundary Element Method). Stress singularity near surface of model to analyze is observed for various crack length and ratio of elastic modulus. Tensile and shear stress distribution near two neithbor sub-interface crack tips are analyzed. Existance of singularity near surface on the interface is particular situation so that we need to investigate for dissimilar friction welded materials by means of numerical analysis method.

건축설계과정에서 나타나는 협업프로세스에 관한 연구 : 파빌리온 설계사례를 중심으로

김정훈,김소희,임병민,김진아,송정화,오건수 남서울대학교 2007 남서울대학교 논문집 Vol.13 No.4

This study aims to deduce the effective collaborative process of architectural design process based on the specific pavilion design case. The study schematizes the collaborative procedure which is generated at the early stage of design process, analyzes the decision support system and suggests the method for reaching a compromise.Finally, this study suggested collaborative process method of architectural design and provided the basic concept that can be used for the similar projects. Keywords : Collaborative Design, Design Process

미역의 알긴산 추출에 미치는 Exo-polygalacturonase의 영향

이동훈,오정훈,황용일,조용진,이승철 Institute of Genetic Engineering Changwon National 1998 Gene and Protein Vol.2 No.1

Alginic acid is a polysaccharide originated from sea mustard. and has been widely used as functional food additives in the food industry. In this experiment, we developed an effective extraction method of alginic acid from sea mustard(Undaria pinnatifida) by an enzymatic method with ego-polygalacturonase ( EPG). The optimal conditions for the extraction of alginic acid with EPG were at 30℃ and pH 7.0, for 12 hours of incubation at a ratio of 1:100 of enzyme to substrate. The yield of enzymatic method and acid-alkali extraction method were shown 34.00% and 20.80%, respectively.

Polymethylmethacrylate Microspheres(PMMA-NewPlastic®)로 치료한 칼자국상 2예

박정훈,오두진,강승훈,황선욱,조시형,박성욱 대한피부과학회 2006 대한피부과학회지 Vol.44 No.4

매복된 견치의 Tunnel을 통한 교정적 견인

전정훈,오유향,이난영,이창섭,이상호 大韓小兒齒科學會 2005 大韓小兒齒科學會誌 Vol.32 No.1

매복된 상악 견치를 위한 외과적 수술을 동반하는 교정치료는 주위조직에 손상을 주지 않고 치열궁내에 적절히 위치시켜야 한다. 이를 위해 매복된 치아의 위치에 따라 다양한 외과적, 교정적 방법이 소개되었으며, 그 방법으로 window procedure, apically positioned flap, closed eruption technique, tunnel traction 등이 있다. 깊은 골연하 매복에서 사용할 수 있는 방법으로 closed eruption technique 그리고 tunnel traction이 있는데, closed eruption technique은 점막 및 치은 하방으로 지나는 견인 와이어의 자극으로 염증 발생 가능성이 높으며 치은퇴축 및 부착 치은의 소실이 발생할 수 있다. 하지만, tunnel traction은 치아의 맹출이 터널을 통해서 유도되어 각화치은에 둘러싸인 채 치조골의 중앙으로 나오게 되므로 치은퇴축이나 치주부착의 소실 없이 적절한 각화치은을 얻을 수 있으며 매복치가 치조골의 중심부로 맹출함에 따라 생리적 맹출과 같은 효과 얻을 수 있다. 본 증례는 깊은 매복을 보이는 상악 견치를 tunnel traction을 이용한 치료를 보고한 것으로, 적절한 방향을 가지고 맹출하였으며 치은퇴축이나 부착치은의 소실이 발생하지 않았다. The impacted maxillary canine is a common problem of which all dental practitioners should be aware. The surgical orthodontic treatment of impacted canines is replaced correction position in dental arch without periodontal damage. Many treatment possibilities have been considered for this goal; window procedure, apically positioned flap, closed eruption technique and tunnel traction. Prognosis for these treatment may be very uncertain in many case(infraosseous impacted tooth). Other steps are required to achieve a satisfactory periodontal outcome. Satisfactory results could be expected if the physiologic eruption pattern is restored by tunnel traction, because permanent tooth erupts through the gingiva near the crest of the ridge so that periodontal damage is reduced. This article report that the surgical orthodontic treatment using tunnel traction is obtained proper position and reduced periodontal damage in facially impacted maxillary canines.

인공 치아우식 발생 모델에서 디지털 방사선 공제술을 이용한 인접면 치아우식증의 진단

박정훈,최용석,황의환,이기자,최삼진,박영호,김경숙,진현석,홍경원,오범석,박헌국 대한구강악안면방사선학회 2009 Imaging Science in Dentistry Vol.39 No.1

Purpose : The purpose of the experiment was to evaluating the diagnostic ability of dental caries detection using digital subtraction in the artificial caries activity model. Materials and Methods : Digital radiographies of five teeth with 8 proximal surfaces were obtained by CCD sensor (Kodak RVG 6100 using a size #2). The digital radiographic images and subtraction images from artificial proximal caries were examined and interpreted. In this study, we proposed novel caries detection method which could diagnose the dental proximal caries from single digital radiographic image. Results : In artificial caries activity model, the range of lesional depth was 572-1,374 μm and the range of lesional area was 36.95-138.52mm². The lesional depth and the area were significantly increased with demineralization time (p<0.001). Furthermore, the proximal caries detection using digital subtraction radiography showed high detection rate compared to the proximal caries examination using simple digital radiograph. Conclusion : The results demonstrated that the digital subtraction radiography from single radiographic image of artificial caries was highly efficient in the detection of dental caries compared to the data from simple digital radiograph.

고속치환 영상처리를 위한 암호화 기법에 관한 연구

윤정오,이훈재,홍영호,최병진 경운대학교 산업기술연구소 1998 産業技術硏究論文誌 Vol.1 No.1(A)

In this paper, we suggest a new encryption system for high speed permutation image processing. We show how to secure attack relative to redundancy in image data. In addition, by applying the proposed permutation algorithm in image data, we show how to solve problems related to scanning sequence and scraming.

비집속빔을 이용한 CO_2 레이저 빔 조사강화

서정,이제훈,강희신,김정오,이문용,오상진,이규현 한국레이저가공학회 2003 한국레이저가공학회지 Vol.6 No.2

Defocused CO_2 laser beam irradiation strengthening of 60kgf/㎟ grade steel sheet was investigated to obtain the tensile strength similar to that of fully penetrated one by the focused beam. The melted line width by the defocused beam was 3∼4 times larger compared to that of the focused beam. However, the increase of tensile strength with 1 line irradiation by the defocused beam was similar to that of 2∼3 lines by the focused beam. The increase(37.6%) of bending strength with 1 line by the defocused beam was higher than the increase(12.9%) of tensile strength. Also, the effect of cooling gas to strengthening was observed.

Superconducting MgB2 Wire Drawing Considering Anisotropic Hardening Behavior and Hydrostatic Effect

Young‑Seok Oh,Ho Won Lee,Kook‑Chae Chung,Duck‑Young Hwang,Seong‑Hoon Kang,Jeong Whan Yoon 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.7

Numerical modeling was conducted to investigate the deformation behavior of powder mixture during multi-pass drawingprocesses for multi-filamentary MgB2wire. A modified Drucker-Prager Cap (DPC) model with an elliptical cap surface usingthe new material characterization method was developed to capture the anisotropic hardening behavior and hydrostatic effectof the powder mixture. A number of uniaxial die compaction, cold isostatic pressing, diametrical compression, and uniaxialcompression tests were conducted using different powder densities to characterize the modified DPC model. A commercialfinite element software ABAQUS with a user subroutine was used to simulate the drawing of the MgB2wire. The densityand area fraction of the powder mixture during the wire-drawing process were verified with experimental results. The differencein packing density at the inner and outer filaments of the MgB2wire was successfully captured by simulation. Inaddition, the effect of the initial packing density on the superconducting properties of MgB2wire was numerically studied. It is shown that the increase in the superconducting area, which results from a high initial packing density, should be moreeffective compared to the increase in the grain connectivity in enhancing the critical current properties for the MgB2wirewhen the final packing density is saturated after a number of drawing processes.