• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.149-153
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• 2023

In this study, structural design and analysis of a duct stand for blowers were performed. This structure was an axial fan and blower for wind tunnel of the vehicle environmental test chamber. The design of the blower duct stand support structure was performed by investigation on various loads. Additionally, self-weight of the motor and weight of the duct were investigated and applied. The duct stand structure was designed by analyzing the load. The safety of the structural design results was evaluated through finite element analysis. Finally, the safety of the design result was verified.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11b
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• pp.427-429
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• 2005

최근 컴포넌트 기반의 소프트웨어 프로덕트 라인에 대한 연구와 소프트웨어 프로덕트 라인에 자동 생성 프로그래밍 기법을 적용하기 위한 연구가 활발히 진행 중이다. 본 논문에서는 재사용 가능한 컴포넌트 자산을 구축하고, 재구성 자동화를 통해 컴포넌트 코드를 생성하는 시스템을 제안한다. 본 도구는 컴포넌트 기반 프로덕트 라인 개발 방법론과 자동 생성 프로그래밍 기법, XML/XSLT 기술을 이용하여 구축되었다. Component Asset 개발자 레벨에서 사용하는 컴포넌트 자산 구축기와 재사용자 레벨에서 사용하는 컴포넌트 코드 생성기로 구성되어 있으며, 컴포넌트 기반의 소프트웨어 프로덕트 라인 개발에 효과적으로 활용될 수 있다.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.45-55
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• 2004

In this study, a time marching free wake method was used for the aerodynamic analysis and the boundary element method was used for the aeroacoustic analysis of the Tail Fan, respectively. In addition, variations of blades position in duct were performed and the aeroacoustic analysis shows a marginal improvement in noise level.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.29 no.2
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• pp.39-45
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• 2000

1970년대부터 사용된 변풍량 공조 시스템 (Variable Air Volume System)은 실내 부하 변동에 따라 급기 온도를 일정하게 유지시키고 실별, 존별 송풍량을 변화시켜 실온을 제어하는 방식으로, 에너지 절약, 개별 제어 등의 장점 때문에 적용이 확대되었고 특히 단일덕트 변풍량 공조 시스템은 이러한 이유 때문에 많은 건물에 적용되고 있다. 그러나 현 제어시스댐의 풍량 측정의 문제점과 공조기내에서 풍량변화 및 급/배기 댐퍼의 개도 변경으로 인한 환기 댐퍼의 비선형 특성을 고려하지 않고 제어하기 때문에 외기량 확보를 정확히 유지 못하는 실정이다. 따라서 단일덕트 변풍량 시스템의 환기댐퍼 및 급기, 환기 팬의 제어 방식의 종류와 특성 및 문제점에 대하여 설명하고자 한다.

• The Journal of the Acoustical Society of Korea
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• v.26 no.3
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• pp.115-122
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• 2007

In this study, the property and the structure of micro-speaker had been firstly shown to be treated as a ducted speaker-system, which was consisted of the unit and the ducted enclosure. With the decrease of total hole area. the resonance frequency of micro-speaker was decreased due to increasing the stiffness or reducing the compliance. The behavior of resonance frequency relative to the total hole area was exactly agreed with that of the square root of compliance. With decreasing the total hole area. the effective chamber volume was increased, but the reference sound pressure level was exponentially reduced in the low and middle frequency range.

• Journal of KIISE:Software and Applications
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• v.31 no.8
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• pp.1010-1026
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• 2004

The goal of product line engineering is to support the systematic development of a set of similar software systems by understanding and controlling their common and distinguishing characteristics. The product line engineering is a process that develops reusable core assets and develops a set of software-intensive systems from a common set of core assets in a prescribed way. Currently, many software development technologies are accomplished in context of product line. However, much of the product line engineering research have focused on the reuse of work products relating to the software's architecture, detail design, and code. The product lines fulfill the promise of tailor-made systems built specifically for the needs of particular customers or customer groups. In particular, commonality and variability play central roles in the all product line development processes. These must be treated already during the requirement analysis phase. Requirements in product line engineering are basis of software development just like as traditional system development engineering, and basis of deciding other core assets' property - commonalities and variabilities. However, it is difficult to elicit, analyze and manage correct requirements. Therefore, it is necessary to develop systematic methods which can develop and manage requirement as core asset, which can be stable in anticipative change and can be well adapted to unpredictable change. In this paper, we suggest a method of managing requirements as core asset in product line. Through this method, the reuse of domain requirements can be enhanced. As a result, the cost and time of software development can be reduced and the productivity can be increased.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.19-26
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• 2003

In this paper, the result of the conceptual study of a tipjet driven propulsion system is presented. The concept of a tipjet driven propulsion system is to employ tipjet as power source to drive a rotor Because the vehicle is supposed to takeoff and land vertically, a rotor system, which has tipjet nozzles, is adopted to fly like a helicopter. Exhaust gas, which is generated by an engine, Passes through an internal duct system and divided into four blade ducts. The design code is consists of two parts, engine model and internal duct model. Inside a rotating duct, compressible flow is affected by two additional force terms, centrifugal force and coriolis force and they govern the performance in rotary mode, The intention of this paper is to address the issues associated with sizing and optimizing configurations of a tipjet driven propulsion system especially in rotary wing mode.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1993.10a
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• pp.131-136
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• 1993

본 연구에서는 무한덕트의 경우를 기준으로 하여 반무한덕트(semi-infinite duct)와 유한덕트에서의 소음제어결과를 비교함으로써 반사에 따른 영향을 실험적으로 고찰하였다. 제어는 광대역의 평면파 소음을 대상으로 하였고 적 응필터 기법을 적용하여 실시간으로 감소시키고자 하였다. 또한 원소음의 진 행방향과 반대방향의 음에 대한 마이크로폰의 감도(sensitivity) 역시 능동소 음제어 시스템의 성능을 결정하는 주요 요소로 볼 수 있으므로 두 개의 마 이크로폰으로써 지향성 마이크로폰을 구성.실험을 통하여 그 결과를 고찰하 였다.

• Proceedings of the Korea Information Processing Society Conference
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• 2005.11a
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• pp.275-278
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• 2005

매년 빠른 성장률을 보이는 모바일 컨텐츠 서비스는 아직까지 확립된 표준이 없는 상황에서도 다양한 응용이 예상되고 있어서, 새로운 시스템을 쉽고 빠르게 도입하기 위해서는 체계적인 아키텍쳐의 확립이 요구되고 있다. 컨텐츠 시스템은 컨텐츠에 따른 전송 방식, 또는 제공 형태에 따라 차이를 가지면서도 그 요구 사항과 아키텍처는 유사하여 재사용이 가능하기 때문에 소프트웨어의 핵심적인 공통 자산을 재사용하는 기술인 프로덕트 라인 기술을 적용하는 것이 필요하다. 본 논문에서는 프로덕트 라인 기술 중 UML 기반의 PLUS 방법을 사용하여 끊임없이 변화하는 모바일 컨텐츠 시장에 적용하여 분석, 설계를 통해 변화에 발 빠르게 대응할 수 있도록 한다. 아울러 산출된 아키텍쳐를 적용하여 새로운 모바일 서비스의 요구를 만족하는 프로토타입을 얻을 수 있었다.

• Journal of Bio-Environment Control
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• v.20 no.3
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• pp.176-181
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• 2011

The fan and pad evaporative cooling system is one of the main cooling methods in greenhouses. Its efficiency is very high, but it has some disadvantages as temperature gradient in greenhouse is large. This study was conducted to reduce the internal temperature gradients in the fan and pad cooling greenhouses. Experiments on cooling performance were carried out in a greenhouse equipped with air duct and integrated fan and pad system as an idea of this study. It showed that the cooling efficiency of an integrated fan and pad system was 75.7% in the first stage and 88.6% in the second stage. When this cooling system was operated for an unshaded and a shaded greenhouse, there were cooling effects of $5.7\sim7.6^{\circ}C$ and $7.4\sim9.7^{\circ}C$ to the control greenhouse, respectively. Maximum temperature differences in a cooling greenhouse, with a length of 18m, were $1.6\sim1.7^{\circ}C$ for shaded conditions and $2.3\sim2.7^{\circ}C$ for unshaded conditions. This greenhouse cooling method, with air duct and integrated fan and pad system, can reduce about 40~50% of the internal temperature gradients in the usual fan and pad cooling greenhouses.