• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2005.04a
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• pp.390-393
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• 2005

본 논문은 철도청 사령실 통합 신호설비 구축사업에 적용할 열차 경합의 해소를 위한 시스템에 관하여 논의한다. 열차경합의 검지 및 해소는 열차운행의 정시성을 유지하기 위하여 매우 중요한 기능이지만 현재까지 자동화되지 못하고 지역본부별로 하나의 이벤트에 대하여 해당열차만을 고려하는 수작업의 형태로 경합해소를 수행해오고 있다. 따라서 이러한 문제를 해결하고 철도 시스템을 전역적으로 고려할 수 있는 기법이 요구된다. 본 논문에서는 이를 위하여 열차 경합 해소 시스템의 국내외 기술현황을 바탕으로 우리 실정에 맞는 시스템을 제안하였다. 제안한 시스템은 전문가 시스템에 기반한 것으로 고도의 전문성이 요구되는 열차 경합의 검지 및 해소분야에 효과적으로 적용될 수 있다.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.10a
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• pp.423-428
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• 2002

Due to various advantages over the conventional linear motion device such as ball-screw, linear motors have been used in wide variety of industrial applications for years. Driven by increased demand for precision machine tools, the importance of high positioning accuracy, high stiffness and high thrust are greatly increasing. The merits of linear motor are high speed, high acceleration and good positioning accurcy. In addition, Linear motor for high quality machine tool call for high thrust, high stiffness. In this paper, thrust ripple, detent force and thermal behavior are considered for the development of high performance linear motor whose thrust is up to 4,000N. This paper presents a comprehensive study for an iron core type linear motor characteristics that include the influence of PM position on thrust, thrust ripple by detent force and motor dynamics as well.

• 한국벤처창업학회:학술대회논문집
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• 2018.11a
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• pp.283-288
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• 2018

스타트업의 자금조달 능력은 초기 스타트업 생존에 가장 직결되는 문제이다. 스타트업은 정부 지원금을 비롯하여 엔젤투자자, 벤처캐피탈 등으로부터 자금을 지원받고 있지만 초기기업 회수시장의 불확실성으로 인해 투자 규모는 작은 편이다. 이에 따라 초기기업에 투자함과 동시에 경영 및 기술 멘토링, 교육, 관리 등을 체계적으로 지원하는 '액셀러레이터'가 최근 창업생태계의 핵심으로 떠오르고 있다. 액셀러레이터는 단순하게 인큐베이팅 시스템을 제공하는 것이 아니다. 초기기업의 팀빌딩부터 성장 과정을 함께하는 '공동 창업자'와 같은 역할을 하면서 이들이 성장해나갈 수 있도록 집중적인 멘토링과 교육 등의 프로그램을 제공한다. 이러한 시스템을 거친 스타트업은 생존 기간이 상대적으로 높고, 벤처캐피탈도 이렇게 성장한 스타트업 투자에 보다 더 적극적으로 참여하는 경향이 있다. 하지만 액셀러레이터 설립의 역사가 오래되지 않아, 관련 연구는 비교적 다양하지 않은 편이다. 이에 본 연구에서는 엔젤투자자, 벤처캐피탈과 다른 액셀러레이터의 특징이 무엇인지 분석하고, 특히 액셀러레이터가 스타트업 투자의사결정시 영향을 미치는 요인에는 어떤 것들이 있는지 렌즈모델을 통해 알아보고자 한다.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.4 no.1
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• pp.63-85
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• 1996

의사 결정의 문제는 기본적으로 다수의 상충되는 기준(Criteria)하에서 최적의 대안을 선택하는 문제이며, 특히 국가나 항공사 또는 어느 기관에서 항공기의 구입시 기종 선정의 문제는 항공기 자체의 높은 가격 및 기술 파급효과, 안전성, 경쟁성 등 다수의 요인들을 심도 있게 고려하여야만 한다. 따라서 다수의 전문가 집단의 의견을 종합할 수 있다면 실패의 확률을 줄일 수 있을 것이다. 본 논문은 한국항공대학교의 훈련용 항공기의 도입 필요성이 제기됨에 따라 대상 기종인 Mooney MSE와 Cessna 172RG 기종에 대하여 현재 한국항공대학교에서 비행 교육을 담당하고 있는 운항학과 전임교수와 비행교육원 비행 교관들의 설문을 통하여 계층화 의사결정법을 이용하여 전문가 의견을 종합하였다. 계층화 의사결정법(AHP; Analytic Heirarchy Process)은 1970년대 초 T. L. Saaty에 의해 개발된 기법으로 다수의 목표, 다수의 기준, 다수의 의사결정 주체가 포함되어 있는 의사결정 문제를 계층화한 후, 상위 계층의 한 기준의 관점에서 직하위 계층의 요소들의 상대적 중요도(Relative Importance) 또는 가중치(Weight)를 쌍별비교(Pairwise Comparison)에 의해 측정하여 궁극적으로 최하위 계층의 대안의 우선순위를 구하는 기법으로 앞으로 항공기의 기종선 정시(특히 훈련용 항공기) 계층화 의사결정법(AHP)을 활용할 수 있도록 모델을 제시하고자 하였다.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.1
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• pp.27-40
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• 2013

This study is about development of technology system for an advanced deep-sea unmanned underwater robot of S. Korea analysed by the application of scenario planning. It was developed a 6000m class next-generation deep-sea unmanned underwater vehicle(or robot, UUV) system, soonly ROV 'Hemire' and Depressor 'Henuvy' in 2006 at S. Korea and motion control, adaptive control algolithm, a work-space manipulator control algolithm, especially the underwater inertial-acoustic navigation system robust to initial errors and sensor failures. But there are remained matters on position tracking of the USBL, inertial-acoustic navigation system, attitude sensor, designed sonar sensors. So this study suggest the new idea for settle the matters and then this idea help the development of the underwater inertial-acoustic navigation system robust to initial errors and sensor failures, such as acoustic signal drop-out, by modifying the error covariance of the failed sonar signal when drop-out occurs. As a result, the future policy for deep-sea unmanned underwater robot of S. Korea is to further spur the development of new technology and more improvement of the technology level for deep-sea unmanned underwater robot system with indicator and imaginary wall as external device.

• The Journal of the Korean Society for Microbiology
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• v.7 no.1
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• pp.9-15
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• 1972

The authors identified 45 Shigella cultures among 63 suspectable cultures obtained from the cases showing dysentery or the like symptoms in various parts of the country during the period from February to September, 1971. Of 45 cultures, 36 cultures belonged to Subgroup B, 7 cultures to Subgroup C and 2 cultures to Subgroup D. There was none of cultures belonging to Subgroup A in 1971, although the authors detected one culture of that among 41 identified Shigella in 1967. Of 36 cultures belonging to Subgroup B, 27 cultures were $B_{2a}$ and 3 cultures of each $B_{3c},\;B_{4a}$ and $B_y$ were serotyped, respectively. Of 7 cultures beloning to Subgroup C, one was $C_{11}$ and other six cultures were $C_{15}$ and all S. boydii were isolated in Seoul area. It might be possible to suggest that there was a tendency of decreasing prevalence of S. dysenteriae and of increasing prevalence of S. boydii in Korea, although the number of cultures. tested were very much limited to conclude, if it was compared with the results obtained by the authors in 1967 that the fourty-one identified Shigella were composed of one culture of S. dysenteriae, 36 cultures of S. flexneri, 4 cultures of S. sonnei and none of S. boydii. According to the results obtained from the biochemical tests, the positive ratio of Indol tests in Subgroup B was 31/36, which could be higher than 9/36 observed in 1961, but which was nearly correlated with the result published by Ewing and his colleagues in U.S.A. The positive rates of both sorbitol and raffinose were lower than that observed by Ewing and his colleagues in S. flexneri. Regarding with the sensitivity of Shigella cultures to the antibiotics being widely used in the country, 46.2% were sensitive to chloramphenicol, which was very much higher than that observed by Park, and 85.8% were sensitive to ampicillin, which would be the drug of choice according to the results from the In Vitro tests.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.237-244
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• 2011

Vehicular communications extend their application areas by combining communication technologies with roads/vehicles, and one of major applications is Smart Highway project. Smart Highway is a new advanced highway system which enhances the current highway system in Korea by improving reliability, safety and convenience. In this paper, we introduce wireless access technologies for vehicular communications especially focusing on Smart Highway. We first introduce the overall communication system architecture and the basic service and communication requirements for Smart Highway. Then, we discuss wireless access technologies including L2-level hand-over scheme. In addition, the results of experimental measurements of Wireless Access in Vehicular Environments (WAVE) system are introduced.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.87-92
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• 1998

Unaided visual acuity was tested by ACP-7 TOPCON chart projector on 376 kindergarteners and objective refraction error was measured by NIDEK ARK-700A auto-refractokeratometer on 554 eyes aged 3 to 5. The results were as follows ; The average unaided visual acuity of children aged 3 was 0.82, aged 4 was 0.90 and aged 5 was 0.92 respectively theerfore children s visual acuity has been gradually developed with their age. The kind of refractive error was 1% for hyperopia, 14% for hyperopic astigmatism, 3% for myopia, 50% for myopic astigmatism, 18% for mixed astigmatism and 14% for emmetropia respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.17-22
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• 1999

In this study, corneal power and eye refraction error were studied on myopic of unaccommodated koreans. The mean of refraction error power is -2.39D(male : -2.75D, female : -2.02D). The mean of corneal refraction error power is +43.90D(male : +44.07D, female : +43.71D). It is +0.90D higher than that of the model eye by Gullstrand(about + 43.00D).

• Journal of Korean Society of Transportation
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• v.26 no.5
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• pp.217-226
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• 2008

The term, travel-time reliability, refers to variations in journey time that travelers cannot predict. The purpose of this paper is to suggest a standard way to measure travel time reliability. A modified buffer time indicator is proposed. The index is represented by the difference between planned and actual travel times based on lognormal type travel time distribution. Using this framework, a constant function for railways and a negative parabola function for roads are discussed. The model developed is applied to the real data of Korean road and rail usages to empirically verify the methodology proposed. In this process, the unit value of travel time reliability for each group is estimated. The result of this research is expected to be helpful of conducting more cautious economic feasibility studies of transport.