• 한국ITS학회:학술대회논문집
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• 2002.11a
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• pp.193-197
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• 2002

• Journal of Astronomy and Space Sciences
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• v.11 no.2
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• pp.308-319
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• 1994

We can launch satellites only at a certain time which satisfies special conditions, since the current techniques cannot overcome these constraints. Launch window constraints are the eclipse duration, solar aspect angle, attitude control, launch site and the launch vehicle constraints, etc. In this paper, launch window is calculated that satisfies all these constraints. In calculating launch window, the basic concepts are relative locations of the sun-satellite-earth system and relative velocities of these, and these requires geometric consideration for each satellite. Launch window calculation was applied to Kitsat 2(low earth orbit) and Koreasat(geostationary orbit). The result is shown in the form of a graph that has dates on the X-axis and the corresponding times of the given day on the Y-axis.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.941-947
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• 2008

In the braking of a railroad car, mechanical brake systems using wheel tread and brake disk are applied as well as electrical brake systems by regenerator and rheostat. During disk braking, kinetic energy of the vehicle is converted into thermal energy through friction between disk and brake pad. And it causes high temperature concentration and generates thermal crack on the brake disk surface. In this study, comparative test process for heat-resistance of candidate materials was designed for development of brake disk materials having high heat-resistance. We also verified the efficiency of the process by experiments using conventional brake disk materials.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.3 no.4
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• pp.839-847
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• 1999

This paper presents the performance evaluation of direct broadcasting satellite by monte-carlo(MC) and quasi-analytic(QA) simulation method in the existence of uplink/downlink adjacent channel interference(ACI), co-channel interference(CCI), and gaussian noise. Korea's satellite system parameters and link design are used at the simulation. MC and QA simulation methods are a valuable adjunct to analytical performance.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.210-218
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• 2000

It is absolutely important to design passenger seat so that train passengers can satisfy because passenger seat is one of the most important parts in tile determination of passenger's satisfaction for train.. So, it is necessary to consider passengers' characteristics, requirements, and dissatisfactions in seat design. However, passengers' dissatisfactions for the seat of Mugunghwa-ho train have been often raised through various routes. It is necessary to resolve their dissatisfactions to provide comfortable trip to passengers. So, we designed a seat of new Mugunghwa-ho train that resolved passengers' dissatisfactions. Our focusing design parts were the seat pan and the backrest of passenger seat. We investigated passengers' dissatisfactions for the seat of Mugunghwa-ho train through various methods and the human factors design guidelines of passenger seat through literature survey. We designed a new seat on the basis of investigated results. For newly designed seat, we evaluated comfort, sensible satisfaction, and fitness in comparison with the existing seat. An experimental method and a subjective method were used in this evaluation. In all aspects, new seat was superior to the existing.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.394-399
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• 2004

Train is one of the most famous and convenient transporting ways. However, the noise problem caused by the train hinders people from living in a silent environment. Furthermore, this problem is related with the environmental rights of people nearby the railroad. The estimation of train noise is the pre-research of train noise reduction. This research is about measurement and analysis of train noise which can be a base-study about the estimation of train n(lise. The noise of ‘Mugungwha’ train, the most frequently used train in Korea, is the main object in this measurement and analysis. The characteristics of the train noise were evident in the criteria of height, distance and velocity. Furthermore, the noise differences between locomotive and passenger coach were observable.

• IE interfaces
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• v.14 no.2
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• pp.210-217
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• 2001

Because passenger seat is one of the most important parts in the determination of passengers' satisfaction for train, it is absolutely important to design the passenger seat so that train passengers can satisfy. So, in the seat design it is necessary to consider passengers' characteristics, requirements, and dissatisfactions. However, passengers' dissatisfactions for the seat of Mugunghwa-ho train have been often raised through various routes. It is necessary to resolve their dissatisfactions to provide comfortable trip to passengers. So, we designed a new seat of Mugunghwa-ho train that resolved passengers' dissatisfactions. Our focusing design parts were the seat pan and the backrest of passenger seat. We investigated passengers' dissatisfactions for the seat of Mugunghwa-ho train through various methods and the human factors design guidelines through literature survey. We designed a new seat on the basis of investigated results. For newly designed seat, we evaluated comfort and sensible satisfaction in comparison with the existing seat. An experimental method and subjective methods were used in this evaluation. In all aspects, the new seat was superior to the existing.

• Aerospace Industry
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• v.70
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• pp.21-23
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• 1999

우리나라 우주기술은 선진국에 비해 초보단계의 수준이나 위성체 구조물 기술, 로켓 구조체 기술 및 위성수신기기 분야 등에서는 상당수준의 기술을 확보하였다. 92년 발사된 실험용 소형과학위성인 "우리별 1호"로 우주개발에 착수한 우리나라는 무궁화위성 1,2호 사업을 통해서 위성통신 시스템 및 관련부품에 대한 요소기술을 확보한 상태이며, 다목적 실용위성 개발사업을 통해서 우주산업 기반기술을 확보한 단계이다. 이번호에서는 오는 12월에 발사예정인 다목적실용위성의 개발과정과 의의에 대해서 알아 보기로 하겠다.

• Defense and Technology
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• no.12 s.286
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• pp.74-83
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• 2002

현재 군에서 사용 중인 통신위성의 활용현황은 무궁화 위성 2호 트랜스폰더(Transponder) 1조를 임대하여 상용휴대용, 차량용, 해상용, 공중용 단말기를 이용하여 운용중에 있으며, 해사통신위성(INMARSAT)을 활용하여 원거리 통신망으로 운용중에 있다. 그러나 이와 같은 위성통신 체계만으로는 한반도 지역의 미래전장을 주도적으로 이끌어 갈 수 있는 지휘통제통신체계를 구현할 수 없기에 앞으로 개발 될 위성통신체계에 대한 사용자, 즉 군의 운용관점에서 요구사항을 식별하여 제시하고자 한다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1752-1753
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• 2011

본 연구에서는 K-water에서 수문관측용으로 무궁화 5호 위성을 이용하여 홍수예보망의 원격 데이터 취득하는데 있어서, 효율적인 위성통신망 운영을 위하여 위성 수신신호 분석용 프로그램을 자체 개발하여 모니터링하고 있으며, 이를 통하여 수신신호가 낮은 관측국에 대한 문제점 제시와 해결방안을 모색코자 하였다.