• 한국정보통신학회논문지
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• 제24권11호
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• pp.1457-1462
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• 2020

스마트폰에는 다수의 응용 프로그램들이 탑재된다. 이 응용 프로그램들의 탑재, 삭제, 배치 등을 관리하는 서비스 응용 프로그램을 런처라고 하며 다양한 런처들이 사용된다. 기존 런처들 중에서 응용 프로그램의 사용자 활용 패턴들을 분석하여 아이콘을 자동으로 배치하는 기능을 제공하는 것도 있다. 본 논문에서는 스마트 폰 화면에서 아이콘들이 균형을 이루도록 아이콘을 자동으로 배치하는 방식을 제시한다. 사례를 통하여 이 방식의 자동 배치가 사용자에게 유용함을 보였다. 이 경우 높이가 m이고 너비가 n인 m × n 화면 레이아웃에서 n이 홀수이면 전체 화면이 n 값과 관계없이 항상 균형을 이루도록 배치할 수 있음을 수학적 귀납법으로 증명하였다.

• 한국분말재료학회지
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• 제29권6호
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• pp.477-484
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• 2022

Thermal protection systems (TPS) are a group of materials that are indispensable for protecting spacecraft from the aerodynamic heating occurring during entry into an atmosphere. Among candidate materials for TPS, ceramic insulation materials are usually considered for reusable TPS. In this study, ceramic insulation materials, such as alumina enhanced thermal barrier (AETB), are fabricated via typical ceramic processing from ceramic fiber and additives. Mixtures of silica and alumina fibers are used as raw materials, with the addition of B4C to bind fibers together. Reaction-cured glass is also added on top of AETB to induce water-proof functionality or high emissivity. Some issues, such as the elimination of clumps in the AETB, and processing difficulties in the production of reusable surface insulation are reported as well.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.451-462
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• 2024

In order to optimize the operational safety and reliability of the upper launcher for the CFETR ECRH system, a design of the launcher based on the remote steering concept is currently being carried out for comparison with the front steering equivalent. This paper presents the remote steering system's conceptual design and simulation analysis. A Square Corrugated Waveguide (SCW) of 65 × 65 mm has been designed with an optimized length of 9.35 m. By changing the relative length of the waveguide, the transmission efficiency of the SCW is optimized within the range of steering angles ±12°. Different error factors are investigated in detail, and corresponding acceptable error ranges are provided. Considering these error factors and ignoring ohmic losses and thermal effects, the relative transmission efficiency of the SCW is estimated to be >98 % within the steering angle range. A matching steering unit for the SCW is designed, which consists of an ellipsoidal focusing mirror and a steerable flat mirror. The detailed design of the steerable mirror motion trajectory is presented. Also, the influence of the possible beam incident errors caused by the steering unit on the transmission efficiency is analyzed in detail.

• 한국항공우주학회지
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• 제31권4호
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• pp.123-131
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• 2003

• 한국항공우주학회지
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• 제31권9호
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• pp.129-136
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• 2003

• 한국항공우주학회지
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• 제31권9호
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• pp.121-128
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• 2003

• 한국항공우주학회지
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• 제32권7호
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• pp.142-148
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• 2004

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2011년도 춘계학술대회 논문집
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• pp.1121-1122
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• 2011

• Advances in aircraft and spacecraft science
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• 제5권2호
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• pp.205-223
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• 2018

During launch a spacecraft is subjected to a variety of dynamical loads transmitted through the launcher to spacecraft interface or air-born transmission excitations in the acoustic pressure field inside the fairing. As a result, spacecraft are tested on ground to ensure and demonstrate the global integrity of the structure against these loads, to screen the flight hardware for quality of workmanship and to validate mathematical models. This paper addresses the numerical modelling and simulation of the low frequency sine and random vibration tests performed on electrodynamic shaker facilities to comprise the mechanical-borne transmission loads through the launcher to spacecraft interface. Consequently, the paper reviews techniques and methodologies to derive a reliable and representative coupled virtual vibration testing simulation environment based on experimental data. These technologies are explored with the main objectives to ensure a stable, reliable and accurate control while testing. As a result, the use of the derived simulation models in combination with the added value of improved control and signal processing algorithms can lead to a safer and smoother vibration test control of the entire environmental test campaign.

• 한국전자파학회논문지
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• 제16권5호
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• pp.518-525
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• 2005

본 논문에서는 위성 발사체와 같은 원통 도체에 UHF 대역의 역 F 안테나가 장착되어 있을 때 방사 패턴을 시뮬레이션하고 분석하였다. 우선 파라미터를 변화시켜가면서 장착될 역 F 안테나 자체의 특성을 분석한 다음, 이 역 F 안테나가 원통 도체에 장착된 경우에 대하여 시뮬레이션하고 분석하였다. 특히 역 F 안테나의 개수, 원통의 길이, 그리고 원통의 직경 변화에 대하여 방사 패턴을 시뮬레이션하고 분석하였다. 다음으로 역 F 안테나를 제작하여 반사 손실을 측정하고 원통 도체에 장착하였을 때 방사 패턴을 측정하였다. 측정 결과와 시뮬레이션 결과는 서로 잘 일치함을 확인하였다.