초음파 tomography를 응용한 콘크리트 구조물의 비파괴 시험에 관한 연구

김영기,윤영득,윤종열,김정수,김운경,송문호,Kim, Young-Ki,Yoon, Young-Deuk,Yoon, Chong-Yul,Kim, Jung-Soo,Kim, Woon-Kyung,Song, Moon-Ho 대한전자공학회 2000 電子工學會論文誌-SP (Signal processing) Vol.37 No.1

As a potential approach for non-destructive testing of concrete structures, we evaluate the time-of-flight (TOF) ultrasound tomography technique In conventional X ray tomography, the reconstructed Image corresponds to the internal attenuation coefficient However, in TOF ultrasound tomography, the reconstructed Image is proportional to the retractive index of the medium Because refractive effects are minimal for X-rays, conventional reconstruction techniques are applied to reconstruct the Image in X-ray tomography However, since ultrasound travels in curved path, due to the spatial variations in the refractive index of the medium, the path must be known to correctly reconstruct the Image. Algorithm for determining the ultrasound path is developed from a Geometrical Optics point view and the image reconstruction algorithm, since the paths are curved It requires the algebraic approach, namely the ART or the SIRT Here, the difference between the computed and the measured TOP data is used as a basis, for the iteration process First the initial image is reconstructed assuming straight paths. It then updates the path based on the recently reconstructed image This process of reconstruction and path determination repeats until convergence The proposed algorithm is evaluated by computer simulations, and in addition is applied to a real concrete structure. 본 연구에서는 초음파와 tomography 기법을 기반으로 콘크리트 구조물의 비파괴 시험에 대한 방법론을 정립하고 검증하였다 일반적인 X-ray tomography에서는 물체를 통과하는 파동의 감쇠(attenuation) 데이터에 기초를 두고있는 반면에, 본 연구에서는 time-of-flight(TOF) 데이터를 사용하여 매질의 굴절률(refractive index)을 포괄적으로 표현하는 단층영상을 복원한다 X-ray tomography에서는 측정된 감쇠 데이터를 영상복원(Image reconstruction) 알고리즘에 의해서 처리하며, 파동의 굴절은 고려할 필요가 없다 그러나 초음파는 매질(medium)의 굴절률(refractive index)에 따라 초음파의 경보가 변경되므로 초음파 tomography에서는 초음파 경로의 연산이 선행되어야만 단층영상을 복원할 수 있게 된다 초음파 정보의 연산은 가하광학(Geometrical Optic)에서 사용되는 굴절률과 경로의 관계에 기초를 둔다 영상 복원은 대수학적 접근 방법인 ART (algebraic reconstruction technique) 또는 SIRT(simultaneous iterative reconstruction technique)를 기초로 연산된 초음파의 경로를 따라 선적분한 TOF 값과 측정된 TOF 값의 차이를 기반으로 수행된다 실제 구현에서는 초음파가 직진한다는 가정하에 영상을 복원하고, 이를 기반으로 초음파의 경로를 연산하였다 본 논문에서는 이들 두 과정(경로연산 및 영상복원)의 반복연산을 통하여 영상을 복원하였다. 세안하는 알고리즘을 모의실험으로 평가하였고, 실제 콘크리트 구조물에 적용하여 본 방법론의 무한한 가능성을 입증하였다.

어문결합을 지향하는 정음한손자판의 배치와 설계

김영기,진용옥,Kim Yong-Gi,Chin Yong-Ohk 한국정보처리학회 2004 정보처리학회논문지B Vol.11 No.7

자판은 문자론 대상으로 인간과 인지단말기 사이를 이어주는 연결고리로서 인지활동으로 얻어진 지적 내용물을 정보기구로 입력시키는 장치다. 이러한 이유로 자판은 인간과 기계가 어울려지는 인기일체(人機一體)시스템으로 "인지 공학적 고려"와 "행동 과학적 효율"이 동시에 고려해야한다. 본 논문은 정음한글의 정보공학적 특성을 반영하여 한손자판을 배치 하였고, 어문결합에 의한 오인식 정정 및 문장 편집이 가능한 정음한손자판을 설계 및 구현 하였다. Keyboard is a link between human and terminal, so we can input knowledge to information device. The misstyping is occured or the speed is reduced if there would be transmission error. We always have to consider human interface and behavior effect, because the keyboard system is the harmony of human and machine. This paper is designed for representation of ortho-phonics alpabetic one hand strock keyboard which is enable to correct error and to edit word.

포스타토의 ( A ) : 30 . 비조직에서 CD34 의 면역조직학적 규명

김영기,윤건식,김영민,( Young Ki Kim,Kyun Sik Yoon,Young Min Kim,J . A . Denburg ) 대한천식 및 알레르기학회 ( 구 대한알레르기학회 ) 1998 춘계학술대회 초록집 Vol.1998 No.-

서울 지역 소아의 구인강에서 폐구균 보균율과 항균제 내성

김영기,이창규,Kim, Young Kee,Lee, Chang Kyu 대한소아감염학회 1997 Pediatric Infection and Vaccine Vol.4 No.2

목 적 : 전 세계적으로 폐구균의 항균제 내성이 증가하고 있고, 우리 나라의 경우 그 어느 나라보다 급속한 폐구균 내성의 증가가 보고 되고 있다. 일반적으로 상기도에 정착되어 있던 폐구균은 부비동염, 중이염, 수막염, 폐렴들을 일으키는 것으로 알려져 있어 저자들은 정상 소아의 구인강에서 폐구균의 보균율을 알아보고 이들의 항균제 내성양상과 DNA분자 형별을 조사하였다. 방 법 : 1997년 4월 서울 한 유치원의 어린이 117명에서 구인강 점막을 면봉으로 도말하여 검체를 얻었다. 이들을 배양후 optochin검사와 capsule에 대한 다가항체를 이용하여 Latex 방법으로 폐구균을 동정하였고, 디스크확산법으로 페니실린, vancomycin, erythromycin, TMP-SMZ에 대한 감수 검사를 시행하였다. 분리된 폐구균에 대하여 액체배지 미량 희석법을 이용하여 페니실린의 MIC값을 구하였다. 또 분리된 폐구균들에 대하여 REP1R-Dt와 REP2-Dt primer를 사용한 rep-PCR법으로 DNA 분자 형별을 시행하였다. 결 과 : 서울지역의 유치원에서 폐구균 보유율은 38%(45/117)였고, 디스크 확산법에 의한 페니실린 내성 폐구균의 비율은 89%(40/45)였고, erythromycin은 91%, TMP/SMZ은 63%였고 vancomycin에는 모두 감수성을 보였다. 그리고 페니실린에 고도 내성균주는 21예로 전체의 47%를 차지하였고 다제내성 폐구균은 64%였다. DNA 분자형은 7가지로 분류할 수 있었고, 이중 3가지 유형이 전체의 78%를 차지하였다. 결 론 : 서울 지역의 건강한 유치원 어린이들이 보유하고 있는 폐구균의 항균제 내성이 예상보다 훨씬 높았고, 이는 이들 어린이들이 빈번한 항균제 노출과 유치원의 밀집환경의 때문이라 추정된다. Purpose: The antimicrobial resistance of S. pneumoniae has encountered with increasing frequency from around the world. In our country, penicillin resistant strains of S. penumococci are rapidly increasing. It has been known that colonized pneumococci in upper respiratory tract cause sinisitis, otitis media, meningitis and pneumonia. We tried to reveal the colonization rate of pneumonocci in upper respiratory tract, their antimicrobial resistance and DNA fingerprinting pattern in normal children. Methods: We got specimens from 117 children of day-care center in Seoul through oropharyngeal swab. After incubation on BAP, optochin test and slide latex agglutination test were used for identification. Antimicobial susceptibility test to penicillin, vancomycin, erythromycin and TMP-SMZ was done with disk diffusion method. Penicillin MIC was gotten through the broth microdilution method. Genotyping of 45 pneumococci was done by rep-PCR using REP1R-Dt and REP2-Dt primer. Results: The carriage rate of pneumococci in the day-care center children was 38%(45/117). The resistance of penicillin, erhthromycin, TMP/SMZ, vancomycin by the disk diffusion method are 89%, 91%, 64% and 0%, respectively. 64% of the isolates showed multiple resistance. 7 types of DNA fingerprinting were gotten and 78% of isolates belonged to three types. Conclusion: We found that the antimicrobial resistance of children attending the day-care center in Seoul was much higher than expected. We assumed that this might be due to their easy and frequent exposure to antimicrobial agents and crowded day-care center environment.

대구(大邱) 지역(地域)의 사암(砂岩) 및 규장암(珪長岩)에 대(對)한 분리면(分離面)의 활동성(活動性)

김영기,최일환,정교철,Kim, Young Ki,Choi, El Whan,Jeong, Gyo Cheol 대한자원환경지질학회 1983 자원환경지질 Vol.16 No.4

The Cretaceous sandstone and felsite distributed in north-western border part of Taegu city were studied in the viewpoint of engineering geology with an emphasis of their discontinuities. The probability of continuity of sandstone is 0.69 and that of felsite is 0.56. The correlation coefficients of sandstone are 0.52 and 0.54. Those of felsite are 0.47 and 0.48. These values reflect that the rocks have been strongly jointed. $K_0$ value of the sandstone is close to its $K_a$ value and the test suggests that the sandstone has been in active state. On the other hand, $K_0$ value of the felsite is close to its $K_p$ value, which reflects that the felsite has been in passive state, in order to maintain the stability of the sandstone. $\delta$ value should be changed to be less than 13.2.

Patent Valuation for Fair Royalty Distribution in Patent Pool

김영기,박성택,이승준,Kim, Young-Ki,Park, Seong-Taek,Lee, Seung-Jun The Society of Digital Policy and Management 2010 디지털융복합연구 Vol.8 No.1

In this paper, we discuss patent pool and a patent valuation scheme for fair royalty distribution among the patents in a pool. In the knowledge-based economy, intellectual capital-the accumulation of technology and know-how-is recognized as the most important source of company's competitive advantage and economic growth. By providing exclusive rights to patent holders, the patent system aims to encourage innovation-invention & commercialization of new technologies-in order to raise the standard of living. However, drawbacks of patent system, which occur as the number of patents issued increases rapidly and patent ownership is fragmented, may slow down the innovation efforts seriously. A promising solution is the patent pool approach, which was for instance employed by the U.S. congress during World War I to free the airplane manufacturers from the patent tangle by letting them license all the patents for a fee. It is necessary to figure out relative technological contribution of patent for fair distribution of royalty revenues among patent holders. The Rating/Ranking Method seems to fit to that valuation purpose. We examined technology valuation models from various organizations and selected a set of more influential valuation factors which can be incorporated as scoring criteria in the Rating/Ranking Method.

e-learning 컨텐츠 품질에 관한 연구

김영기,박성택,이승준,Kim, Young-Ki,Park, Seong-Taek,Lee, Seung-Jun 한국디지털정책학회 2008 디지털융복합연구 Vol.6 No.2

The remarkable growth of the Internet since mid-l990s has expanded the e-learning market and brought the transformation of educational environments and methodology. It can be said that the e-learning has changed the educational paradigm. Korean government is firmly determined to support the diffusion of e-learning because of the benefits of e-learning. People seem to accept the e-learning when its contents have high quality. A lot of research have been conducted on e-learning, however, it was mostly about user's usage intention, satisfaction and educational effect. It can't seem that sufficient research efforts have been put into figuring out the role of e-learning contents quality in the expansion of e-learning. In this paper, we present the empirical study on the influence of e-learning contents quality on user's satisfaction and educational effect. We conducted an questionnaire survey on college students to collect data and found that the quality of e-learning contents has significant influence on the users' satisfaction.

고속 입자 충격을 도입한 AC PDP의 MgO 보호층 형성에 관한 연구

김영기,박정태,고광식,김규섭,조정수,박정후,Kim, Young-Kee,Park, Jung-Tae,Ko, Kwang-Sik,Kim, Gyu-Seob,Cho, Jung-Soo,Park, Chong-Hoo 대한전기학회 2000 전기학회논문지C Vol.52 No.10

The performance of ac plasma display panels (PDP) is influenced strongly by the surface glow discharge characteristics on the MgO thin films. This paper deals with the surface glow discharge characteristics and some physical properties of MgO thin films prepared by reactive RF planar unbalanced magnetron sputtering in connection with ac PDP. The samples prepared with dc bias voltage of -10V showed lower discharge voltage and lower erosion rate byion bombardment than those samples prepared by conventional magnetron sputtering or E-beam evaporation. The main factor that improves the discharge characteristics by bias voltage is considered to be due to the morphology changes or crystal structure of the MgO thin film by ion bombardement during deposition process.

예능계 입시 공동관리의 당위성

김영기,Kim, Yeong-Gi 한국대학교육협의회 1988 大學敎育 Vol.36 No.-

반야월층(半夜月層)의 지하수운동(地下水運動)에 관(關)한 연구(硏究)

김영기,Kim, Yong Ki 대한자원환경지질학회 1976 자원환경지질 Vol.9 No.4

This study deals with the flow of bed rock ground water of Banyaweol Formation, which is presently cleared up as a laminar flow. The result obtained may be summarized as the following. 1) The Banyaweol Formation consists mainly of thin-bedded, green to blackish green shale, mudstone, and marl. The marl and mudstone alternatively occur with shale. The marl and mudstone form a aquifer of Banyaweol Formation. In this study, a group of aquifer is in convenience named as a aquifer zone. The aquifer occurs in lenticular form. The aquifer seems to be a type of artesian aquifer because it is covered with aquicludes, but it actually forms a unconfined aquifer because its piezometric surface stays under the lower aquiclude. The lowering of piezometric level is formed because of leakage of the ground water to the lower aquifer undersaturated. 2) The coefficient of permeability of Banyaweol Formation's ground water body (K) is derived by using Dupuit's equation as the following ${\log}K=\frac{CK^2-dK+f}{aK-b}\;\(M=1.365(2H-s)s\\M={\log}1.956s{\sqrt{H}}r\)$ here, $$a=\sum_{1}M_iG_i$$ $$b={\frac{1}{2}log{\sum_{i}}Q_i{^2}$$ $$c=2{\sum_{i}}M_i{^2}$$ $$d=loge{\sum_{i}}M_{i}Q_{i}+2{{\sum_{i}}N_{i}Q_{i}$$ $$f=loge{\sum_{i}}Q_i{^2}N_i$$ If the measured values substituted for the above equation, the coefficient of permeability of the aquifer is 4.1m/day. The coefficient of storge of the aquifer is $2.8{\times}10^{-4}$ if the measured values substituted for Theis's equation. Using the above constants, the filtration velocity of the aquifer is $2.1{\times}1O^{-1}m/day$and the daily flow quantity of the ground water is $847.38m^{3}/day$. 3) In order to understand the time necessary for a circulation of ground water body, the contents of tritum contained in the ground water are measured as 2.3 T.U. at the Korea Atomic Energy Research Institute. Before 1952, the average concentration of tritium per year in groundwater was reported as 10T. u., taking it as the standard, the groundwater of the present study 26.25 years old. Therofore, the groundwater of the Banyaweol Formation is judged as an relatively old groundwater. It is characteristic that the ground water of Banyawol Formation is laminar flow as well as unconfined aquifer and ground water flow of relatively long time. 4) The nature, means of flow, and circulation of Banyaweol Formation's ground water body make it possible set up this ground water body as a ground water system.