ATM망 트래픽 제어 알고리즘 연구

유진호,손준영,안재환,박성우,김명수,장혁수 明知大學校 産業技術硏究所 1996 産業技術硏究所論文集 Vol.15 No.-

ATM(Asynchronous Transfer Mode) is a transmission technique for the B-lSDN(Broadband Integrated Service Digital Network). Congestion problems are unavoidable in the ATM networks, since various traffic typos coexist in the networks. The preventive congestion control algorithm is widely used for the real time traffics such as voice and video. The reactive congestion control algorithm works well for the non-real time traffic within a short distance. A mixed traffic control algorithm is proposed, which works either preventively or reactively based on traffic types. The proposed algorithm sets a high and low threshold value at the output buffers and modifies the EPRCA(Enhanced Proportion Rate Control Algorithm) to control loss-sensitive cells. Delay-sensitive cells are handled by the priority control and the UPC(Usage Parameter Control) algorithm. The performance analysis shows that the proposed traffic control algorithm works well for both the VBR(Variab1e Bit Rate) and ABR(Available Bit Rate) traffic with small buffers

플륨 모니터링에 의한 SM45C 레이저 용접특성 평가

유영태,김재열,노경보,양동조,오용석,임기건,김지환 한국공작기계학회 2003 한국생산제조학회지 Vol.12 No.6

With the increased use of lasers in industrial welding applications, techniques for monitoring and controlling these processes become increasingly important. It is very important that we understand the dynamic behaviors of the laser induced plume in welding because the laser induced plume has considerable effects on welding efficiency and the quality of materials. As the plume fluctuation was associated with keyhole instability, unstable vapor plume indicated the process was unstable and would result in poor welds. An Infrared Themal-vision Camera can be utilized compensate for incurracies encountered in real-time monitoring during laser welding. We have results that instabilities of plume are closely dated with hot cracking and defect of laser welding.

打擊速度 및 溫度變化가 豫크랙을 가진 衝擊試驗片의 動的破壞靭性에 미치는 影響

兪在煥,李敬奉,金重吉,李致雨,吳世旭 慶南大學校 附設 工業技術硏究所 1989 硏究論文集 Vol.7 No.-

計裝化衝擊試驗에서 打擊速度와 溫度의 變化가 豫크랙을 揷入한 衝擊試驗片의 動的破壞靭性에 미치는 影響을 考察한 結果 다음을 알 수 있었다. 豫크랙을 揷入한 試驗片이 V-노치 試驗片에 比하여 實驗値의 分散度가 적으며 0℃以下의 溫度領域에서 動的破壞靭性의 有效性이 있었다. 또한 打擊速度와 實驗溫度의 影響은 溫度가 速度보다 훨씬 上廻하는 傾向이었다. The effect of various impact velocity and temperature on dynamic fracture toughness is tested with precracked Charpy specimen, and conclude following results. Precracked specimen has less dispersion of test results than V-notched specimen, unstable crack initiation load didn't agreed to maximum load at room temperature but at 0℃ below, thus, the availability of dynamic fracture toughness is relatively high. Comparing V-notched specimen, the precracked Charpy specimen represented lower shelf of temperature different. But, at this time, the absorbed energy is estimated equivalently. With the decrease of temperature, the reduction of fracture toughness was obvious, but the effect of impact velocity didn't appear.

Al Sheet/CFRP 다적층 하이브리드 복합재료의 굴곡강도에 미치는 카본섬유 체적률 및 배열방향 영향

유재환 한국안전학회 2004 한국안전학회지 Vol.19 No.4

The A17075/CFRP multi-layered hybrid laminate material consists of the alternating A17075-T6 sheets and carbon/epoxy prepregs of M40 grade. The influence of volume fraction and fiber orientation of A17075/CFRP layer on flexural properties of A17075/CFRP laminate alternating A17075-T6 and carbon/epoxy prepreg was investigated. The results obtained from the experimental analysis are as follows: 1. In the 0° fiber orientation, the amount of increase of the flexural rigidity was 20.5% at the 26.5% volume fraction and 38.0% at the 35.7% volume fraction compared with the flexural rigidity level(20.OGPa) of the 10% volume fraction of CFRP. 2. In the ±45° fiber orientation, the amount of decrease of the flexural rigidity was 23.5% at the 20.0% volume fraction and 31,5% at the 33.3% volume fraction compared with the flexural rigidity level of the 101/o volume fraction of CFRP. 3. In the 0° fiber orientation, the flexural strength was 481.5MPa at the 101/o volume fraction of CFRP and 583.8MPa at the 26.5% volume fraction and 653.7MPa at the 35.7% volume fraction. 4. In the ±45° fiber orientation, the flexural strength was 354.OMPa at the 20.0% volume fraction of CFRP and 340.5MPa at the 33.3% volume fraction.

수완진동 증후군에서 신경장해의 조기진단을 위한 객관화된 방법

윤재국,이헌,최나리,김석환,박형욱,이지호,유철인 大韓産業醫學會 2009 대한직업환경의학회지 Vol.21 No.2

목적: 통각과 진동감각 역치검사 및 수부와 수지의 악력, 그리고 수지의 운동기능검사(태평) 등과 근로자들이 호소했던 증상에 대한 HAVS의 스톡홀름 워크샵 분류와의 관련성을 통해 좀 더 객관화된 신경학적 조기검사 방법을 찾고 타당성을 검증하고자 하였다. 방법: 2000년 1월부터 2007년 12월까지 수부진동에 폭로되고 수부의 불편함을 호소하여 진동 장해에 대한 검사를 시행한 497명의 근로자를 대상으로 하였다. 일차적으로 문진을 통해 직업력에 대해 알아보고 과거력을 조사했다. 대상자들의 스톡홀름 워크샵 분류에 따른 소견을 확인하고 수부의 말초 순환기능 검사(손톱압박, 수지피부 온도), 신경기능 검사(통각과 진동각 역치), 운동기능 검사(악력, 태평) 등을 시행하였다. 다른 질환의 감별을 위한 몇 가지 이학적 검사를 실시하고 스톡홀름 워크샵 분류에 따른 검사 결과들을 분석하였다. 결과: 사용 도구는 그라인더 단독 사용이 265명 (67.3%)으로 가장 많았으며 평균 노출 연수는 14.8년이었다. 통각과 진동감각에서 스톡홀름 워크샵 분류 단계에 따른 역치가 증가하는 경향을 보였으나 통각은 양측 모두 통계적인 유의성이 없었고, 진동감각은 125와 250 Hz에서 양측 모두 유의했다(p=0.006-0.038). 수부와 수지의 악력은 단계가 올라갈수록 감소하는 경향을 보였지만 수부와 수지 모두 우측에서만 통계적으로 유의했다 (p=0.041, p<0.01, p=0.034). 태평 첫수는 단계가 올라 가면서 전반적으로 태핑 첫수가 감소하였으며 좌측에서만 통계적으로 유의했다(p=0.002-0.019). 결론: 본 연구는 수부 진동 노출자들의 수부 불편함에 대한 신경계통을 초기에 정량적으로 객관화하여 진단할 수 있는 단일 방법은 아직 없으며 일상생활의 불편함과 스톡홀름 워크샵 분류 등을 통한 주관적인 증상에 더하여 수지 통각과 진동감각 역치검사, 수부와 수지 악력검사, 운동기능검사(태핑) 등을 통합하면 초기에 객관적으로 진단하는 것이 가능할 것으로 판단된다. Objectives: In order to determine find out the best methods for a more objective detection of neurologic abnormality in early hand ann vibration syndrome(HAVS), early with analyzing the validity of each of the detection methods was analyzed. We evaluated the relationships between the sensorineural stage of Stockholm-revised vibration syndrome classification and the results of several tests. Methods: 497 workers were investigated for symptom, exposure duration, the types of tools used, and medical history from January 2000 to December 2007. Pain sense threshold, vibrotactile threshold, hand grasp force, finger grasp force, and a finger tapping frequency test were performed by the workers. Results: The grinder(67.3%) was the most commonly used tool and the mean exposure duration was 14.8 years. Although the pain sense and vibrotactile threshold level tended to increase according to sensorineural stage of the Stockholm classification, there was statistically significant difference in the vibrotactile threshold of 125, 250 Hz (P=0.006~0.038) but not in the pain sense threshold. Hand and finger grasp force tended to decrease according to the sensorineural stage of Stockholm classification and there was statistically significant difference(P=0.041, <0.001, 0.034) only on the right hand side. The tapping frequency also generally decreased according to the sensorineural stage of the Stockholm classification and there was statistically significant difference (P=0.002~0.019) only on the left hand side. Conclusions: Although there is no single standardized method that can objectively diagnose the Sensorineural component of early HAVS early, the combination of subjective symptoms, the sensorineural stage of Stockholm classification, the pain and vibrotactile threshold test, the hand and finger grasp force, and the finger agility (tapping) test can objectively detect sensorineural component of HAVS early.

로봇프로그래밍 학습이 초등학생의 논리적 사고력 신장에 미치는 영향

채재호,배영권,유인환 韓國敎員大學校 敎育硏究院 2008 敎員敎育 Vol.24 No.2

로봇 교육의 필요성에 대한 관심이 고조되면서 초등학교에서도 방과 후 교실 등의 방법으로 로봇을 교육적으로 활용하는 사례들이 증가하고 있다. 이와 더불어 지식기반사회의 핵심 요소인 창의성을 향상시키기 위한 방법으로 프로그래밍 교육을 초등학교에서부터 실시해야 한다는 연구가 받표되고 있다. 이에 본 연구에서는 로봇을 활용하는 프로그래밍 교육은 학습 동기 유발이나 논리적 사고력 및 문제해결력 신장에 도움을 줄 수 있을 것으로 기대하고 초등학교 프로그래밍 교육에서 로봇의 활용을 제안하였다. 또한,로봇 프로그래밍 학습 프로그램을 개발하고,○○교육대학교 부설 정보영재교육원의 초등학생을 대상으로 적용한 결과,논리적 사고력 중 비례 논리,확률 논리,상관 논리,조합 논리가 신장된 것으로 나타났다. 따라서 본 연구에서 실시한 로봇프로그래밍 학습이 학습자의 논리적 사고력을 신장시키는데 기여 했다고 볼 수 있으며,본 연구에서 제안한 로봇을 활용하는 프로그래밍 교육은 초등 학생을 위한 프로그래밍 교육에 다양하게 응용될 수 있을 것이다. With the increasing concern about the necessity of robot education, there have increased the cases where the education is conducted by applying robot programming after school at an elementary school. Together wlth this, the research on the necessity that basic curriculum for enhancing creativity be implemented from the elementary course, and the cases where the demand for robot programming education so that motivation for learning, or logical thinking abilities and problem-solving abilities could be promoted have been also on the increase. Therefore, this study tries to develop and apply a programming education program for information prodigies by using a robot to investigate effects of such program on growth of logical thinking. As a result of applying the developed method to 20 fifth graders of an information prodigy education facility elementary school, annexed to an educational college, it turned out that, out of all logical thinking abilities, proportional logic, probabilistic logic, correlation logic, and combinational logic have significantly increased. Therefore, a robotic programming education that uses the proposal in this study is contributed to enhance logical thinking abilities and is expected to be very good for programming education for elementary students.

연령이 다른 Bald/Caj 생쥐의 피부창상치유중 섬유모세포의 동원

유영현,김동환,고재승,한성수,한성수,한성수 대한해부학회 1994 Anatomy & Cell Biology Vol.27 No.4

Risk Based Inspection 기법을 이용한 화학공장의 안전성 향상에 관한 연구

노용해,유진환,서재민,임차순,고재욱 한국산업안전학회 2002 한국안전학회지 Vol.17 No.3

The RBI technique proposed by API is composed of three steps. The qualitative RBI method can be used for the purpose of screening the components with high risk. And, the quantitative RBI method employs complex risk evaluation model for predicting component risk in a quantitative manner. The inspection program can be optimized based on the results obtained by these RBI technique. The forementioned RBI technique has been applied to a common hydrodesulfurizer unit and the technique is critically evaluated for studying its benefits and limitations, which is the main issue of this thesis. It's conducted that the RBI method can provide a method for defining and measuring the component risk, and also provide a powerful tool for managing many of the important elements of a process plant.

신경성 염증질환에서 지질 신호전달물질인 lactosylceramide의 역할

이윤선, 유재명, 최경미, 이용문, 홍진태, 윤여표, 유환수 충북대학교 약품자원개발연구소 2007 약학논문집 Vol.22 No.-

-본문참고-

연구논문 : 항공기 배출량 산정 방법에 따른 공항주변 대기오염 영향분석연구

한승재 ( Seung Jae Han ),유정우 ( Jung Woo Yoo1 ),임윤진 ( Yoon Jin Lim ),이순환 ( Soon Hwan Lee3 ),이화운 ( Hwa Woon Lee ) 한국환경과학회 2014 한국환경과학회지 Vol.23 No.12

Emissions from aircraft have impacts on the air pollution of airport and the surrounding area. There are methods of emissions calculated as Tier 1, Tier2, Tier 3A and Tier 3B. Thus, this study investigated emissions from aircraft at the Gimhae International Airport using EDMS(Emissions & Dispersion Modeling System) program. Results of estimation from aviation emissions, Tier 3B considering all parts which can occur at the airport has the largest amount emissions. In order to understand the relation between aviation emissions and distribution of ozone concentration over airport area, numerical evaluation were carried out. Although the difference of surface ozone distribution between numerical assessment with and without aviation emissions was little, effects of air pollution at airport area from aviation emissions of NOx and VOCs.