일방향 응고법을 이용한 Mar M-247LC 초내열합금의 액상 물성 측정

김현철,이재현,서성문,김두현,조창용,Kim, Hyeon-Cheol,Lee, Jae-Hyeon,Seo, Seong-Mun,Kim, Du-Hyeon,Jo, Chang-Yong 한국재료학회 2001 한국재료학회지 Vol.11 No.9

Directional solidification experiments have been carried out at the solidification rates from 0.5 to 50$\mu\textrm{m}$/s in Mar M-247LC superalloy in which several important liquid properties were estimated by analyzing the interface stability and temperature gradient at the solid/liquid interface. The diffusion coefficient in the liquid was estimated by employing the constitutional supercooling criterion. The temperature gradients changed with solidification rates and latent heat of solidification. The thermal conductivities of solid and liquid could be estimated by heat flux balance at the solid liquid interface.

온도별 구리금파리(Lucilia sericata)의 발육

김현철,김수정,윤지은,조태호,최병렬,박정규,Kim, Hyeon-Cheol,Kim, Soo-Jung,Yun, Ji-Eun,Jo, Tae-Ho,Choi, Byeong-Reol,Park, Chung-Gyoo 한국응용곤충학회 2007 한국응용곤충학회지 Vol.46 No.1

Maggot therapy는 1900년대 초부터 압박성 욕창, 당뇨나 괴사에 의한 궤양, 수술 후 감염된 상처, 화상 등의 상처치료에 다시 사용되기 시작하였다. 환부에 처리할 적절한 발육단계의 무균유충을 생산하고, 증식 보존용 계통을 유지하는 데 필요한 자료를 얻기 위하여 온도별(15.4, 20.6, 22.5, 26.2, 29.1, $33.0^{\circ}C$) 발육실험을 수행하였다. 간배지(liver agar medium)에서 알기간과 1령 및 2령 기간은 $33.0^{\circ}C$에서 각각 9.0시간, 14.0시간, 18.6시간으로 가장 짧았다. 3령 기간과 번데기 기간은 $29.1^{\circ}C$에서 각각 285.0시간과 171.0시간으로 가장 짧았다. 온도별 발육기간을 기초로 각 발육단계의 발육영점온도와 유효적산온도를 산출하였다. 암수 성충은 대개 1개월 이상 생존하였고, 암컷은 일평생 2.7회 산란하였으며, 총 338.5개의 알을 낳았다. Maggot therapy (MT) has been re-introduced for non-healing wounds such as pressure sore, diabetic and necrotic ulcers, as well as infected surgical wounds, burn, and trauma injuries since early 1990s. For the production of sterile maggot of proper developmental stage, Lucilia sericata were studied on developmental periods of immature stages on liver agar medium under six different temperatures such as 15.4, 20.6, 22.5, 26.2, 29.1, and $33.0^{\circ}C$, and adult longevity and egg Production under $29^{\circ}C$. The periods of eggs and larvae of the 1st and the 2nd instars were shortest at $33^{\circ}C$ by 9.0, 14.0 and 18.6 hours, respectively. The periods of the 3rd instar larvae and pupae were shortest at $29.1^{\circ}C$ by 285.0 and 171.0 hours, respectively. Developmental zero point and total effective temperature far the development of each stage were calculated based on the developmental periods. Adults of both female and male lived more than one month. Females laid an average of 338.5 eggs through 2.7 times of egg laying throughout her lifetime.

Special Issues - 신기술.신공법 도입 및 개발을 통한 원전건설 기간 단축

김현철,Kim, Hyeon-Cheol 대한전기협회 2009 전기저널 Vol.- No.395

광역경제권과 지역 경쟁력

김현철,Kim, Hyeon-Cheol 대전발전연구원 2008 대전발전포럼 Vol.28 No.-

유럽의 EMC(Energy Management Course) 벤치마킹을 다녀와서

김현철,Kim, Hyeon-Cheol 대한석유협회 2005 석유와 에너지 Vol.2005 No.7

학술자료 III: 야생 조류 및 포유류의 주걱흡충과 흡충 2 Strigeidae Railliet, 1919 of Wild Birds and Mammals in Korea

김현철,이재구,Kim, Hyeon-Cheol,Lee, Jae-Gu 대한수의사회 2011 대한수의사회지 Vol.47 No.1

루프 캐리 종속성을 가진 루프의 할당 기법

김현철,유기영,Kim, Hyeon-Cheol,Yu, Gi-Yeong 한국정보과학회 2001 정보과학회논문지 : 시스템 및 이론 Vol.28 No.8

본 논문에서는 루프 반복들 간에 종속 관계가 존재하는 루프의 효율적 수행을 위한 새로운 루프 할당 기법을 제안한다. 그리고, 중앙 큐를 사용하여 공유 메모리 다중처리기에 루프 반복을 할당하는 기존 셀프 스케쥴링 기법들을 루프 캐리 종속성(loop-carried dependence)을 가진 루프의 할당에 적용하기 위해 제안한 기법을 이용한 그들의 변형에 대해 알아본다. 종속 거리를 고려하여 루프를 세 단계별로 할당하는 제안된 CDSS(Carried-Dependence Self-Scheduling) 기법 또한, 중앙 작업 큐를 기반으로 한 것이며 별도의 스케쥴러가 필요 없는 셀프 스케쥴링 알고리즘이다. 종속거리, 프로세서 수, 반복 수, 스케쥴링 연산 시간 등을 다양하게 하여 변형된 할당 기법들과 비교 분석한 결과, 제안한 기법은 양호한 부하 균형을 유지하였으며 변형된 다른 기법들에 비해 루프 수행 시간을 줄여 효율적임을 알 수 있었다. 다양한 실험 환경에서 평균적으로 제안한 CDSS, 변형된 SS, Factoring, GSS, CSS 기법 순으로 루프 수행 시간 측면에서 좋은 성능을 보였다.

악관절잡음 및 동통을 동반한 정복성 관절원판 변위환자에 대한 관절강 Pumping 효과

김현철,최종훈,박혜숙,김종열,Kim, Hyeon-Cheol,Choi, Jong-Hoon,Park, Hye-Suk,Kim, Chong-Youl 대한안면통증구강내과학회 1999 Journal of Oral Medicine and Pain Vol.24 No.1

Pumping into the upper joint cavity of the TMJ was done on patients who had reducible disc displacement with pain. This article discusses the change in TMJ sounds before and after the Pumping treatment. 20subjects(mean age of $32.1{\pm}10.2yr$)were selected among those who visited the department of Oral Medicine of Yonsei University for the treatment of craniomandibular dysfunctions. Through a thorough history taking, clinical exam and X-ray taking these subjects were diagnosed as reducible disc displacement patients, and they were subdivided into two groups as acute and chronic according to the time the TMJ sound was made. Sonopak was used to measure the TMJ sound before, right after and one-week after the Pumping treatment. VAS was used to measure the degree of subjective TMJ complaints(sounds and pain) before and one-week after the Pumping treatment. Vibration related items included total integral, high integral, low integral, ratio of high integral to low integral, peak amplitude, peak frequency and median frquency. 1. It was not statistically significant between the acute and chronic groups before the treatment. However, total integral, high integral, low integral, peak amplitude, peak frequency, median frequency showed to be greater in the chronic group. 2. In all the subjects, just after the Pumping treatment was done, total integral, high and low integral, peak amplitude and peak frequency significantly decreased (p<0.05). Even after one week, low integral, peak frequency and median frequency significantly decreased (p<0,05), and the TMJ sound diminished accordingly. 3. Comparing the two groups(before and right after the Pumping treatment), there was the following difference ; in the acute group, high integral, high amplitude, high frequency and median frequency significantly decreased(p<0.05). In the chronic group, total integral, high integral, low integral, ratio, peak amplitude and peak frequency significantly decreased(p<0,05). It was not statistically significant between the acute and chronic group. 4. Comparing the two groups(right after and one week after the Pumping treatment), there was the following difference : in the acute group, high integral, high amplitude, high frequency and median frequency significantly decreased(p<0.05), In the chronic group, low integral significantly decreased(p<0.05). However, although it was not statistically significant, after one week, there was an increase in total integral, ratio, peak amplitude and peak frequency compared to right after the treatment group. 5. In the VAS of before and one week after the Pumping treatment of the TMJ pain and sound, the TMJ pain significantly decreased(p<0.05) in both the acute and chronic group. However, it was not statistically significant between the two groups. There was a statistically significant decrease(p<0.05) in the TMJ sound in the acute group after one week of Pumping treatment, but no change was notable in the chronic group and it was not statistically significant between the two groups. From the above results, we can conclude that Pumping into the upper joint cavity of patients having reducible disc displacement is effective in reducing clicking and pain. Therefore, it can be applied in diverse clinical fields.

학습된 지식의 분석을 통한 신경망 재구성 방법

김현철,Kim, Hyeon-Cheol 한국정보과학회 2002 정보과학회논문지 : 소프트웨어 및 응용 Vol.29 No.5

다층신경회로망 구조의 재구성은 회로망의 일반화 능력이나 효율성의 관점에서 중요한 문제로 연구되어왔다. 본 논문에서는 신경회로망에 학습된 은닉 지식들을 추출하여 조합함으로써 신경회로망의 구조를 재구성하는 새로운 방법을 제안한다. 먼저, 각 노드별로 학습된 대표적인 지역 규칙을 추출하여 각 노드의 불필요한 연결구조들을 제거한 후, 이들의 논리적인 조합을 통하여 중복 또는 상충되는 노드와 연결구조를 제거한다. 이렇게 학습된 지식을 분석하여 노드와 연결구조를 재구성한 신경회로망은 처음의 신경회로망에 비하여 월등히 감소된 구조 복잡도를 가지며 일반적으로 더 우수한 일반화 능력을 가지게 됨을 실험결과로서 제시하였다. It is known that restructuring feed-forward neural network affects generalization capability and efficiency of the network. In this paper, we introduce a new approach to restructure a neural network using abstraction of the hidden knowledge that the network has teamed. This method involves extracting local rules from non-input nodes and aggregation of the rules into global rule base. The extracted local rules are used for pruning unnecessary connections of local nodes and the aggregation eliminates any possible redundancies arid inconsistencies among local rule-based structures. Final network is generated by the global rule-based structure. Complexity of the final network is much reduced, compared to a fully-connected neural network and generalization capability is improved. Empirical results are also shown.

Wireless PACS

김현철,Kim, Hyeon-Cheol 대한디지털의료영상학회 2002 대한디지털의료영상학회논문지 Vol.5 No.1

One of current trends of medical technology is analog to digital. Moreover, The Government put a premium on PACS(Picture Archiving and Communication System) for Medical Insurance in November, 1999. Therefore many hospitals are installing(or planning to install) PACS facilities on their buildings. However most of hospitals didn't consider PACS facilities in the beginning of construction. In particular, the Networking is one of the most difficult things for PACS installation. There is no space for network equipments, and no path for network lines, etc. To solve these problems, wireless network is proposed. The wireless network is divided to three parts mainly. One is the wireless communication for Local Area Network, another is the data transmission through a satellite for Tele-Radiology, and the last one is the technology using Bluetooth for each sub-system of PACS. But there are other problems in wireless systems, i.e., network bandwidth, system stability, interference with other devices. The purpose of this paper is to suggest the future and new trend of PACS including all the problems.