• 한국군사과학기술학회지
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• 제19권3호
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• pp.379-386
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• 2016

In this paper, phase noise analysis result for 2.4 GHz PLL(phase locked loop) using SPD(sample phase detector) is proposed. It can be used for high performance frequency synthesizer's LO(local oscillator) to extend output frequency range or for LO of offset PLL to reduce a division rate or for clock signal of DDS(direct digital synthesizer). Before manufacturing, theoretical estimation of PLL's phase noise performance should be performed. In order to calculate phase noise of PLL using SPD, Leeson model is used for modeling phase noise of VCO(voltage controlled oscillator) and OCXO(ovened crystal oscillator). After theoretically analyzing phase noise of PLL, optimized loop filter bandwidth was determined. And then, phase noise of designed loop filter was calculated to find suitable OP-Amp. Also, the calculated result of phase noise was compared with the measured one. The measured phase noise of PLL was -130 dBc/Hz @ 10 kHz.

• 한국분말재료학회지
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• 제11권2호
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• pp.130-136
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• 2004

The passivation and oxidation process of tungsten and molybdenum narlopowders, produced by electrical explosion of wires was studied by means of FE-SEM, XPS. XRD, TEM, DIA-TGA and sire distribution analysis. In addition, the phase transformation of W and Mo nanopowders under oxidation in air was investigated. A chemical process is suggested for the oxidation of W and Mo nano-particles after a comprehensive testing of passivated and oxidized powders.

• 한국컴퓨터정보학회논문지
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• 제23권12호
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• pp.115-122
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• 2018

As the proportion of software in weapon systems increases, the impact of software on the overall system is growing. As a result, software quality management becomes important, and related regulations and work manuals for quality assurance activities at each stage in the R & D process are becoming more sophisticated. However, due to the characteristics of the weapon system software that is developed as a customized form for the purpose of a specific mission, there are limits to specifying and definitizing the detailed requirements (upper and lower level) according to various operational concepts during the development process. Due to this, software modification (patch change, shape change due to upgrade, etc.) occurs on account of many defects and performance improvement in the mass production and operation stage after the development is completed. In this study, we analyze the characteristics of these weapon system softwares and propose quality improvement methods based on ISO / IEC / IEEE 29119 test method.

• 한국군사과학기술학회지
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• 제14권1호
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• pp.69-73
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• 2011

In the defence wireless communications, conventional Anti-Jamming techniques(Frequency Hopping/Spread Spectrum or Direct Sequence/Spread Spectrum) are used to overcome a intentional interfering signals which are single/multitone or partial band jammer etc. DS/SS techniques is very strong on tone jamming signal but not to be on a partial band jammer. So FH/SS AJ performances are expected method of an substitution of DS/SS, however FH/SS could not have good performance on some BMTJ(Band Multi-tone Jammer). So this paper proposes FH-CSS (Frequency Hopped - Chirp Spread Spectrum) to get more robustness against jammers(BMTJ, PBNJ) and analyze the AJ performances.

• 문화기술의 융합
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• 제9권5호
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• pp.415-419
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• 2023

뉴질랜드군은 제2차 세계대전을 기점으로 여성인력을 활용하기 시작했다. 우수한 인력 확보를 위해 다양한 노력을 기울인 끝에 여성인력의 비율이 24%까지 올라왔다. 이 수치는 군 여성인력의 역사가 뉴질랜드보다 오래된 영국, 미국, 캐나다, 호주보다 높은 수치이다. 이는 전투 직위를 여성에게 개방하고 장성급, 영관급 장교 등 군 고위직에 여성인력이진출할 수 있도록 한 뉴질랜드군 노력의 결과이다. 또한 여성의 현실적인 고민인 임신과 출산, 육아 및 수직적인 조직 문화 등에 대한 정책적 대안을 제시하였으며 특히, 부적절한 성적 행동, 괴롭힘 등으로 우수한 인재가 이탈하거나 입대하지 않는 문제를 극복하기 위해 "존중"작전을 시행했다. 존중 작전은 리더의 역할을 확립하고 피해자의 지원을 강조하였으며 사고의 데이터를 축적하여 유사 사고를 예방했다. 그리고 "Wāhine Toa(여성 전사)"프로그램을 통해 여성인력의 군 생활주기(지원-채용-근속-발전)를 고려한 맞춤형 지원으로 우수한 여성인력이 군에 유입될 수 있도록 하였다. 우리 군도 병력 부족 현상을 극복하고 선진 과학기술 군으로 도약하기 위한 방법 중 하나로 여성인력의 비율과 역할 확대를 고려하고 있다. 뉴질랜드군의 여성인력 활용 사례를 통해 시사점을 도출하여 우리 군이 나아가야 할 방향을 고찰하였다.

• 정보관리연구
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• 제23권2호
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• pp.1-13
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• 1992

본(木) 연구(硏究)에서는 자동색인(自動索引)의 색인어(索引語) 추출(抽出)에 있어 주요한 색인원(索引源)이 되는 표제(標題)와 초록(抄錄)등의 색인성을 비교 분석하였다. 결과는 표제만을 혹은 초록(抄錄)만을 색인원(索引源)으로 선정할 경우에 적절한 색인어(索引語)를 추출할 수가 없었으며, 표제(標題)와 초록(抄錄)을 동시에 색인원(索引源)으로 선정할 경우가 좀 더 적절한 색인어(索引語)를 확보할 수가 있었다.

• 전기학회논문지
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• 제62권9호
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• pp.1318-1323
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• 2013

Thermal insulation material was prepared by cross-linking chemical reaction of silica aerogel and epoxy resin, which has a high porous and vacant properties. The structural, mechanical, and thermal properties were analyzed in order to verify its application for industrial and electrical applications. The thermal conductivities were changed from 115 mW/mK to 75 mW/mK by reducing the contents of nano-porous silica areogel powders. The compressive loading is also decreased by increasing the contents of silica aerogels by 20 wt% in aerogel/epoxy composites. It is concluded that the formulated composite materials can be applied to building materials, electronics parts, and heavy industries.

• 비파괴검사학회지
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• 제18권2호
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• pp.92-102
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• 1998

섬유강화 복합재 연소관은 복합재료의 사용, 필라멘트 와인딩 및 경화공정 등으로 인하여 제작 중 다양한 결함이 발생할 수 있으며, 또한 사용 도중에도 예기치 않은 손상을 받아 기계적 성질이 저하될 수 있다. 따라서 제작 완료된 연소관의 품질 보증을 위해 수압보증시험이 사용되고 있으나 이를 위해 가한 수압이 오히려 연소관에 예기치 않은 손상을 가하여 실제 사용시 그 성능을 저하시키는 요인으로 작용하는 경우도 있다. 이러한 문제를 해결하기 위해 본 연구에서는 수압보증시험시의 음향방출을 감지하여, 그 신호의 특성으로부터 복합재 연소관의 파손 거동을 예측하는 체계적인 기법의 개발을 시도하였다. 음향방출을 이용하여 연소관에 발생한 손상의 개략적 위치를 결정할 수 있었으며, 또한 파괴모드의 식별도 가능하였다. 다만, 시료의 부족으로 최종파열압력의 변화와 충격손상의 영향에 대한 신뢰성 있는 분석은 불가능하였다.

• International Journal of Internet, Broadcasting and Communication
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• 제7권2호
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• pp.137-141
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• 2015

The purposes of this study were to measure university academic achievement based on gender. We analyzed university academic achievement based on gender. The subjects for this analysis were 322 students from freshmen to seniors who received grades in their first semester in the computer engineering department at a university located in the Chungcheong area. The major findings of this study were as follows. First, the average university academic achievement was 3.01. Second, the university academic achievement of female students was higher than that of male students in the entire curriculum, liberal arts, and major subjects. Students showed higher academic achievement when their grades rose. Male students showed higher rate of rise when their grades rose compared to female students. This paper proposes that it is necessary to develop programs to further adaption to university life for males. Since male students showed significantly lower university academic achievement, various programs like counseling and mentoring are needed.

• 한국군사과학기술학회지
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• 제18권1호
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• pp.46-54
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• 2015

Wargame simulators are widely used in the field of defence modeling and simulation. Because of increasing importance of communication effects on the warfare, the war game simulator is also required to reflect communication effects. One way to satisfy the requirement is the interoperation simulation between war game simulator and communication effect simulators. This paper shows the application of interoperation simulation between war game and communication effect simulators using HLA(High-Level Architecture)/RTI(RunTime Infrastructure). The war game simulator mainly deal with the engagement of troops and the troops communicate each other at the mission execution level. In the other hand, The communication effect simulator perform communication actions between the troops in the engineering level. Using the interoperation simulation, we can reflect the communication effects on the war game simulation. We show various applications of the interoperation simulation with the point of the war game and communication effect simulator. with a case study, we explain the interoperation simulation improves the reality and fidelity of the war game simulator and how the interoperation simulation can be applied to developing doctrines and real communication system.