• 시스템엔지니어링학술지
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• 제3권1호
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• pp.9-15
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• 2007

An EA(Evolutionary Acquisition) strategy is based on the systems engineering. It is a preferred approach to provide operationally useful capabilities to the warfighter much more quickly than single-step to full capability strategy. Recently, DoD is trying to apply the acquisition process based on the systems engineering. In spite of these trends, efforts of domestic defense acquisition society to this strategy are insufficient. Although an EA strategy has many benefits, there are many constraints to apply it. This study analyzes these constraints and presents applications of the EA strategy to defense R&D programs.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.373-374
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• 2012

• 한국추진공학회지
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• 제19권1호
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• pp.68-75
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• 2015

본 논문에서는 고체추진기관 밸브의 내부에 장착한 핀틀의 구동 응답, 추력 및 압력 데이터를 이용하여, 연소시험 시 발생한 고체추진기관 내부 압력의 비정상 특성을 분석하였다. 고체추진기관 밸브의 내부에 핀틀이라는 구조체를 장착하여 핀틀의 축방향 구동을 통해서 노즐목 면적을 조절하고, 이를 통해 고체추진기관의 압력 및 추력을 실시간으로 제어할 수 있다. 이때 연소관 내부의 압력에 비정상 특성이 나타날 수 있으며, 이러한 비정상 특성은 다양한 원인이 종합적으로 영향을 미친 결과이다. 이 경우 핀틀의 구동 응답을 이용한 내부 압력의 재예측 및 추력 대 압력 비 분석을 통해서 핀틀 구동 응답 오차와 중공 튜브 삭마에 의한 노즐목 면적 변화라는 두 가지 큰 비정상 특성의 원인을 찾아내고, 각 원인들이 연소관 내부 압력에 미치는 영향을 개별적으로 분석하였다.

• 한국전기전자재료학회논문지
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• 제29권10호
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• pp.652-658
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• 2016

Thermal batteries use inorganic salt as electrolyte, which is inactive at room temperature. As soon as heat pellets are fired by an igniter, all the solid electrolytes are instantly melted into excellent ionic conductors. However, the abnormal heat generation by the igniter flame or heat pellets causes the thermal decomposition of the electrode and the melting of the anode, eventually leading to a thermal runaway, which results in overheating or explosion. The thermal runaway can be significantly reduced by the adoption of $Zr/BaCrO_4$ heat papers. In this study, the heat papers with various ratios of fuel (Zr) and oxidizer ($BaCrO_4$) were prepared by the paper-making process. We have investigated the calorimetric value, burning rate, and ignition sensitivity. The ignition test of heat pellets and the discharge test of thermal batteries were also carried out. At the composition of 40 wt.% of Zr, the heat papers showed the highest specific calorimetric value and burning rate. As a result, $Zr/BaCrO_4$ heat paper made by the paper-making process has shown the applicability for thermal batteries.

• 한국세라믹학회지
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• 제35권1호
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• pp.5-10
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• 1998

Mullitization in a multicomponent oxide system(alumina-kaolin-quartz-feldspar-talc) was studied as a function of sintering temperature from 1200 to 1500$^{\circ}C$ based upon a quantitative X-ray diffraction analysis. In the present study mullite grew as wiskers and its formation reaction showed characteristic there stages as follows In the first stage(1255-1295$^{\circ}C$) an appreciable mullitization(nucleation) occurred while corun-dum dissolution into glass (increasing glass content ) limited the rate of the reaction. At 1295-1335$^{\circ}C$ (second state) the reaction was significantly enhanced with a considerable glass consumption and with no appreciable change in corundum content. Finally (above 1335$^{\circ}C$) the reaction rate was attenuated re-markably with an apparent decrease in glass consumption rate. The impingement of mullite whiskers by oth-er whiskers and crystals was speculated to cause mullite growth in thickness direction with a slow growth rate resulting in the diminished reaction rate in the final stage.

• 한국전자파학회논문지
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• 제29권2호
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• pp.146-149
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• 2018

모노펄스 센서는 수신된 단일 펄스마다 목표물의 각도를 추정한다. 이러한 모노펄스 센서의 각도 추정을 기만하기 위한 방법으로는 크로스 아이 기법이 효과적인 것으로 알려져 있다. 본 논문에서는 크로스 아이 기법의 각도기만 성능을 확인하기 위해 무반향 챔버에 모노펄스 수신 안테나와 크로스 아이 송신기를 이용해 각도기만 시험 환경을 구성한 결과를 소개한다. 그리고 시험 구성을 이용하여 두 개의 크로스 아이 송신기 간격을 변화시키면서 모노펄스 수신 안테나에 인가되는 합 신호와 차 신호의 크기를 측정하고, 그에 해당하는 각도기만 성능을 분석한다.

• 한국군사과학기술학회지
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• 제24권4호
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• pp.382-391
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• 2021

Unsupervised domain adaptation often gives impressive solutions to handle domain shift of data. Most of current approaches assume that unlabeled target data to train is abundant. This assumption is not always true in practices. To tackle this issue, we propose a general solution to solve the domain gap minimization problem without any target data. Our method consists of two regularization steps. The first step is a pixel regularization by arbitrary style transfer. Recently, some methods bring style transfer algorithms to domain adaptation and domain generalization process. They use style transfer algorithms to remove texture bias in source domain data. We also use style transfer algorithms for removing texture bias, but our method depends on neither domain adaptation nor domain generalization paradigm. The second regularization step is a feature regularization by feature alignment. Adding a feature alignment loss term to the model loss, the model learns domain invariant representation more efficiently. We evaluate our regularization methods from several experiments both on small dataset and large dataset. From the experiments, we show that our model can learn domain invariant representation as much as unsupervised domain adaptation methods.

• 한국염색가공학회지
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• 제26권2호
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• pp.71-78
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• 2014

This review paper is a state of the art report of the development of high performance nano-composites with carbon nanotube. We investigate the research and development (R&D) trends of high performance nano-composites with carbon nanotube by analyzing technical trends in research institutes and industry. We report the R&D and technology trends for the properties and applications of fabrication of hybrid composites with aligned carbon nanotubes, multifunctional fiber/carbon nanotube composites. We discuss the specific topics including unidirectional carbon nanotube, carbon nanotube forests, transfer-printing carbon nanotube technology, deposition of carbon nanotube by electrophoresis, vapor grown carbon fiber (VGCF), cup-stacked carbon nanotube, bucky paper and carbon nanotube yarns in this review paper.

• 한국추진공학회지
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• 제22권5호
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• pp.59-65
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• 2018

hydroxyl-terminated polybutadiene(HTPB) 추진제는 자연 저장 기간 동안 내부 시효성 물질들에 의한 물리 화학적 반응으로 인해 서서히 노화가 진행된다. 각기 다른 시간-온도 조건에서 이들 시효성 물질의 가속 노화 시험을 통해 자연 상태에서의 노화 특성을 모사할 수 있다. 본 논문에서는 장기 저장 기간 동안 느리게 진행되는 HTPB 추진제의 물리 화학적 반응에 의한 노화 특성을 HFC(Heat Flow Calorimeter)로 분석 평가하여 수행한 HTPB 추진제의 신개념 수명 예측 기술에 대하여 고찰하였다.

• 품질경영학회지
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• 제44권4호
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• pp.785-798
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• 2016

Purpose: This paper developed the framework for extracting strategies of research and business development (R&BD) based on the data envelopment analysis(DEA). Methods: DEA has been widely utilized in evaluating R&D efficiency. Even though, technology transfer and commercialization has been regarded as the important factors for practical R&D efficiency evaluation, most research have evaluated R&D efficiency by just using the DEA outputs such as the number of patents and papers. The technology transfer, commercialization and relations among costs and generated technology and commercialization are needed to be considered for more practical R&D efficiency evaluation. Thus, this research addressed a method on how to incorporate the commercialization factors into the R&DB efficiency evaluation, and improve the efficiency strategically in terms of R&D and B&D. To achieve this, this research utilized a two-stage network DEA model for R&BD efficiency evaluation. Results: The proposed framework was applied to the 15 public research institutes and the 34 universities for validation. R&BD efficiency for the 15 public research institutes and the 34 universities was evaluated, and the differentiated improvement strategies for the inefficient DMUs to improve their efficient were proposed. Conclusion: The R&BD efficiency would be effectively analyzed based on two-stage network DEA. It would be utilized for the effective strategy planning for cultivating R&BD.