• 제목/요약/키워드: Defence Science and Technology

검색결과 183건 처리시간 0.027초

참기름과 혼합유의 성분 및 NIR Spectrum 분석을 통한 품질특성 비교 (Comparison of Quality Characteristics of Sesame Oil and Blend Oil by Using Component Analysis and NIR Spectroscopy)

  • 주재영;여용헌;이남례
    • 한국식품영양과학회지
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    • 제46권6호
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    • pp.739-743
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    • 2017
  • 참기름에 옥수수기름과 콩기름을 일정비율로 혼합하여 나타나는 품질특성을 연구하였다. 차이식별검사, 색도, 산가, 요오드가, 지방산 조성 및 NIR을 이용하여 데이터를 분석해 보았다. 색도검사 결과 혼합률이 높아짐에 따라 L, a, b 값이 변하는 것을 확인할 수 있었으나, 혼합된 기름의 종류에 따른 특이적인 변화는 확인할 수 없었다. 혼합률이 증가함에 따라 산가는 감소하였지만 혼합유 종류에 따른 차이는 확인하기 어려웠다. 하지만 요오드가의 경우 혼합률에 따른 요오드가 변화 및 혼합유 종류에 따른 요오드가 변화 정도를 확인할 수 있었다. 지방산 조성 분석 결과, 혼합률의 변화와 혼합유의 종류에 따라 linolenic acid 및 특정 지방산 값이 확연히 변하는 것을 확인할 수 있었다. NIR 분석은 다른 분석방법들에 비해 빠른 시간 안에 분석이 완료되었고, 옥수수 기름의 혼합률 변화에 따른 스펙트럼에는 시료 간 차이가 확인되었으나, 콩기름 혼합유 시료에 대해서는 시료 간 차이가 뚜렷하지 않았다. 결론적으로 참기름의 품질특성을 확인해 소비자의 먹거리 신뢰도를 향상시키기 위해서는 여러 가지 분석방법을 이용한 데이터의 축적이 선행되어야 할 것으로 판단되며, 추가적인 연구를 통해 이를 활용할 수 있는 방안이 마련될 것으로 기대된다.

Synthesis of a flight control system via nonlinear model matching theory

  • Uchikado, Shigeru;Kobayashi, Nobuaki;Osa, Yasuhiro;Kanai, Kimio;Nakamizo, Takayoshi
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 1994년도 Proceedings of the Korea Automatic Control Conference, 9th (KACC) ; Taejeon, Korea; 17-20 Oct. 1994
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    • pp.659-664
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    • 1994
  • In this paper we deal with a synthesis of flight control system via nonlinear model matching theory. First, the longitudinal and lateral-directional equations of aircraft motion an CCV mode are considered except the assumption "variations on steady straight flight due to disturbances are very small". Next, a design method of the dynamic model matching control system based on Hirschorn's Algorithm is proposed to the above nonlinear system. Finally, the proposed control system is applied to the small sized, high speed aircraft, T-2 on CCV mode and numerical simulations are shown to justify the proposed scheme.ed scheme.

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군 수송기 운영 효율성 제고를 위한 최적경로 연구 (Effective Route Scheduling for Military Cargo-Plane Operation)

  • 김승기;이문걸;이현수
    • 경영과학
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    • 제33권1호
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    • pp.89-99
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    • 2016
  • A scheduled airlift is the most critical part of the air transportation operations in ROK Air Force. The military cargo-plane routing problem is a PDPLS (pickup and delivery problem in which load splits and node revisits are allowed). The cargo which is transported by a military cargo-plane is measured in pallet. The efficiency of pallet needs to be considered with respect to its volume and weight. There are some guidelines about orders of priorities and regulations in the military air transportation. However, there are no methodologies which can raise the efficiency of flight scheduling using Operations Research (OR) theories. This research proposes the effective computing methodology and the related heuristic algorithms that can maximize the effectiveness of the path routing model.

Design of an IOT System based on Face Recognition Technology using ESP32-CAM

  • Mahmoud, Ines;Saidi, Imen;bouzazi, Chadi
    • International Journal of Computer Science & Network Security
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    • 제22권8호
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    • pp.1-6
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    • 2022
  • In this paper, we will present the realization of a facial recognition system using the ESP32-CAM board controlled by an Arduino board. The goal is to monitor a remote location in real time via a camera that is integrated into the ESP32 IOT board. The acquired images will be recorded on a memory card and at the same time transmitted to a pc (a web server). The development of this remote monitoring system is to create an alternative between security, reception, and transmission of information to act accordingly. The simulation results of our proposed application of the facial recognition domain are very efficient and satisfying in real time.

초음속 노즐과 벽면 충돌제트의 유동특성 (Characteristics of Supersonic Nozzle and Jet Impingement)

  • Hong, Seung-Kyu;Lee, Kwang-Seop;Sung, Woong-Je
    • 한국군사과학기술학회지
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    • 제4권2호
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    • pp.256-262
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    • 2001
  • Viscous solutions of supersonic side jet nozzle and supersonic jet impinging on a flat plate are simulated using three-dimensional Navier-Stokes solver. For rapid and abrupt control of a missile in supersonic flight, side jet on a missile body is found to be a useful devise as evidenced by recent missile development at several nations. The magnitude of the side jet and the duration of it decide the level of control of such a missile system. The aerodynamic characteristics of the side jet devise itself are examined in terms of key parameters such as the side jet nozzle geometry, the chamber pressure and temperature. On the other hand, the jet impinging flow structure exhibits such complex nature as shock shell, plate shock and Mach disk depending on the flow parameters. Among others, the dominant parameters are the ratio of the nozzle exit pressure to the ambient pressure and the distance between the nozzle exit plane and the impinging plane. As the plate is placed close to the nozzle, the computed wall pressure at or near the jet center oscillates with large amplitude with respect to the mean value. The amplitude of wall pressure fluctuations subsides as the plate/nozzle distance increases, and the frequency of the wall pressure is estimated on the order of 10.0 KHz. Objectives of this paper are to show accurate simulation of nozzle flow itself and to demonstrate the jet flow structure when the jet interacts with a wall at a close range.

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p-$Hg_{0.7}$$Cd_{0.3}$Te에 낮은 저항의 접촉을 얻는 방법에 대한 연구 (Low-resistance ohmic contacts to p-$Hg_{0.7}$$Cd_{0.3}$Te)

  • 김관;정한;김성철;이희철;김충기;김홍국;김재묵
    • 전자공학회논문지A
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    • 제31A권10호
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    • pp.87-93
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    • 1994
  • Ohmic contacts between Au and p-HgHg_{0.7}Cd_{0.3}Te$ with low specific contact resistance have been obtained. The contact region of the wafer is first pre-heated for 5 seconds in a rapid thermal processing equipment. The temperature reaches a maximum value of about 200$^{\circ}C$ at the end of the 5 seconds. Next, a thin Au film is formed on the contact region by immersing the sample in AuCl$_{3}$ solution. the sample is then post-annealed in the same condition as the pre-heating after Pb/In pad metals are deposited on the electroless Au contacts. The specific contact resistance measured by transmission line model is 5${\times}10^{-3}{\Omega}cm^{2}$ at 80K. RBS and differential Hall measurement data suggest that the above low resistance ohmic contact is ascribed to surface traps and increased gold diffusion rate.

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한글 코드 변환 인터페이스에 관한 연구 (A Study on Hangul Code Conversion Interface)

  • 윤호상;백두권;황종선
    • 한국정보과학회 언어공학연구회:학술대회논문집(한글 및 한국어 정보처리)
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    • 한국정보과학회언어공학연구회 1990년도 제2회 한글 및 한국어정보처리 학술대회
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    • pp.39-46
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    • 1990
  • 최근 컴퓨터의 발달로 인하여 많은 부분에서 컴퓨터가 사용되고 있다. 그러나 컴퓨터가 한글 사용을 전혀 고려하지 않고 개발되었기 때문에 한글 사용에 많은 문제점이 발생하였다. 본 논문에서는 컴퓨터에서 한글의 사용에 있어서의 문제점을 고찰해보고 이를 해결하기 위하여 한글 코드변환 인터페이스를 연구하였다.

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탄도미사일 궤적 시뮬레이션 모델을 이용한 방어영역 산출 및 응용 (Application and Determination of Defended Footprint Using a Simulation Model for Ballastic Missile Trajectory)

  • 홍동욱;임동순;최봉완
    • 한국군사과학기술학회지
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    • 제21권4호
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    • pp.551-561
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    • 2018
  • Footprint is defined as ground area that is projected from the outer edges of the battle space protected by a defence system. This concept can be effectively used for making decisions on site selection of anti missile systems to defend against enemy's ballistic missiles. In this paper, simulations of ballistic missile trajectories based on various launch conditions are performed first and then the footprint is derived with engagement zone set as a boundary condition. Results of the simulation with various relative positions between the defense system and defended asset are also presented. The proposed method, in which the trajectories are generated based on launch point of the ballistic missile, has an advantage of approximating the defended area close to reality. Two applications are introduced in the present paper to describe how the derivation of defended area could be utilized in deployment decision of defense systems.

Zn-Ion Coated Structural $SiO_2$ Filled LDPE: Effects of Epoxy Resin Encapsulation

  • Reddy C. S.;Das C. K.;Agarwal K.;Mathur G N.
    • Macromolecular Research
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    • 제13권3호
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    • pp.223-228
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    • 2005
  • In the present work, a low-density polyethylene (LDPE) composite, filled with Zn-ion coated structural silica encapsulated with the diglycidyl ether of bisphenol-A (DGEBA), was synthesized using the conventional melt-blending technique in a sigma internal mixer. The catalytic activity of the Zn-ions (originating from the structural silica) towards the oxirane group (diglycidyl ether of bisphenol-A (DGEBA): encapsulating agent) was assessed by infrared spectroscopy. Two composites, each with a filler content of $2.5 wt\%$ were developed. The first one was obtained by melt blending the Zn-ion coated structural silica with LDPE in a co-rotating sigma internal mixer. The second one was obtained by melt blending the same LDPE, but with DGEBA encapsulated Zn-ion coated structural silica. Epoxy resin encapsulation of the Zn-ion coated structural silica resulted in its having good interfacial adhesion and a homogeneous dispersion in the polymer matrix. Furthermore, the encapsulation of epoxy resin over the Zn-ion coated structural silica showed improvements in both the mechanical and thermal properties, viz. a $33\%$ increase in the elastic modulus and a rise in the onset degradation temperature from 355 to $371^{\circ}C$, in comparison to the Zn-ion coated structural silica.

Stability and failure of symmetrically laminated plates

  • Chai, Gin Boay;Hoon, Kay Hiang;Chin, Sin Sheng;Soh, Ai Kah
    • Structural Engineering and Mechanics
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    • 제4권5호
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    • pp.485-496
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    • 1996
  • This paper describes a numerical and experimental study on the stability and failure behaviour of rectangular symmetric laminated composite plates. The plates are simply supported along the unloaded edges and clamped along the loaded ends, and they are subjected to uniaxial in-plane compression. The finite element method was employed for the theoretical study. The study examines the effect of the plate's stacking sequence and aspect ratio on the stability and failure response of rectangular symmetric laminated carbon fibre reinforced plastics composite plates. The study also includes the effect of the unloaded edge support conditions on the postbuckling response and failure of the plates. Extensive experimental investigation were also carried out to supplement the finite element study. A comprehensive comparison between theory and experimental data are presented and discussed in this contribution.