• Ceramist
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• v.14 no.1
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• pp.41-45
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• 2011

지금까지 간단하게나마 MLCC 제품군별로 제품개발 요구사항과 기술개발현황을 살펴 보았다. 2008년 세계금융위기 이후 IT 분야를 중심으로 급증하고 있는 전자부품수요에 대응하기 위해 MLCC 업계는 시장선점을 위한 제품개발과 증설을 서두르고 있으며, 초고용량MLCC로 대표되는 고부가시장의 개척과 생산성향상을 통한 원가경쟁력 확보가 화두가 되고 있다. 세라믹후막기술의 구현 정도에 따라 초고용량 MLCC 개발에 필수적인 소형화 박층화기술의 발전방향이 판가름 날 것으로 보이며, 특히 기초소재가 되는 유전체재료와 나노파우더 합성기술, 그리고 이를 적용할 수 있는 제반 공정기술 및 설비 개발 등의 종합적인 전개를 통해 MLCC 시장이 지속적으로 확대 발전될 것으로 믿는다.

• Defense and Technology
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• no.2 s.252
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• pp.46-57
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• 2000

군 통신도 앞으로 상용에서의 이동통신 시스템이나 ATM(Asynchronous Transfer Mode), 위성통신과 같은 첨단 통신방식으로 발전하는 추세에 있으므로 전술제대 단위로 위치보고체계의 통신망을 구성한다면 상호운용성(Interoperability)면에서 중대한 문제점이 발생할 수 있다. 한편 장차전의 양상은 화력전, 입체 고속 기동전으로 가는 추세이며 기갑/기계화부대는 비선형 기동전의 주역으로서 적의 취약점을 포착하는 즉시 민첩한 기동전투력으로 종심공격을 실시하여 적에게 불리한 비선형의 전장을 적극적으로 조성하고 주도권을 행사하는 전술작전 능력을 발휘한다

• Defense and Technology
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• no.12 s.298
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• pp.34-45
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• 2003

우주는 앞에서 말한 바와 같이 인간의 새로운 활동영역으로 무한한 잠재력을 갖고 있따. 첫 인공위성이 발사된 지 반세기도 안 되었지만 오늘날 우주이용은 국가안보는 물론이고 우리의 일상생활에 있어서도 지대한 영향을 미치고 있따. 현대전의 특징은 엘빈 토플러의 저서 "전쟁과 반전쟁"에서 기술한 것처럼 전격전과 초정밀 타격전이라 할 수 있다. 우주기술은 조기경보와 전장감시, 사각 없는 통신 및 초정밀 측위(GPS)와 유도를 가능케 함으로써 현대적 군사력 건설의 핵심이 되고 있다.

• Journal of National Security and Military Science
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• s.4
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• pp.419-442
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• 2006

In this paper, we introduce the operational management architecture on the military satellite communication of United States and analyze the current problems of Korea military. We discuss on the development scheme and the idea of construction to manage and to operate the next military satellite communication stabilitly.

• Current Industrial and Technological Trends in Aerospace
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• v.6 no.2
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• pp.109-115
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• 2008

There would be a long-waited launch of a Korean space launch vehicle(KSLV-I) in NARO Space Center which is located in Goheung, Jeol La Nam Do in Korea. Korea would be the nineth country in the world which could launch space launch vehicle itself. The launch of the 2nd technology satellite of 100kg with KSLV-I would give Korean hope and dream. In addition to the traditional space activities of U.S.A. and Russia, Japan launched the lunar satellite, Kaguya in 2007, China launched the lunar satellite, Change and succeeded in space walk and India launched the lunar satellite Chandrayaan in October, 2008. In this paper we study on the trend of domestic and international development of space launch vehicle considering all these space development activities.

• Journal of Internet Computing and Services
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• v.21 no.2
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• pp.99-108
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• 2020

In this paper, we analyze the most suitable RA method among PAMA, DAMA, and RA classified by the multiple access method of satellite communication in the rapidly changing traffic environment according to the emergency and tactical situation. It suggests an alternative to improve the limit of output degradation. Based on the CRDSA protocol selected as the standard of DVB-RCS2 among the current satellite communication methods, CRDSA2R (Contention) maintains an optimal RA channel environment by checking the limitations in an environment where packet volume is rapidly increasing and observing channel load and channel conditions. We propose a Resolution Diversity Slotted ALOHA with Adaptive Random Access.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.15 no.3
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• pp.265-270
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• 2004

This paper addresses the effect of group delay in satellite communication system. Phase of signal is distorted by the non-constant group delay. Group delay can be modeled as linear, parabolic and cubic type according to the polynomial characteristic. We investigate BER performance of satellite communication system with each 3 kinds of group delay. As signal bandwidth becomes wider, group delay makes more influence on the signal. BNR performance of satellite communication system is found when data rates are 1Mbps, 4Mbps and 8Mbps. Convolution coding with the code rate of 1/2 or 7/8 is used. At BER =10$\^$-5/, system with group delay needs more SNR of minimum 0.3㏈ to maximum 4.4㏈ than system without group delay. The worst case of BER performance happens in the linear group delay, 7/8 punctured convolution coding and 8 Mbps. The required SNR is increased by 4.4㏈ at this worst case.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.4
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• pp.393-400
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• 2003

This paper deals with the design and manufacturing technique of EQM(Engineering Qualification Model) of input multiplexer(IMUX) for the Ku-band satellite transponder. Channel dropping method by circulator chain structure is adopted for demultiplexing each channel. External equalizers are attached behind channel filters fur reduction of group delay variation and amplitude variation simultaneously. Both channel filters and equalizers adopted dual-mode technique in design f3r mass and volume reduction. Channel filters are designed to have 8-pole elliptic response and equalizers to be of 2-pole reflection type. For good temperature stability characteristics, INVAR36 material is used for channel filters and external equalizers. Vibration test, Thermal Vacuum Test, and EMC test have been performed on input multiplexer and it is shown to be suitable for Ku-band satellite transponder.

• Journal of Satellite, Information and Communications
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• v.5 no.2
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• pp.45-49
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• 2010

This paper presents the study on multi-beam large aperture antenna systems for a satellite payload. Multi-beam large antenna provides the universal communication and broadcasting services to personal portable terminals. The hybrid antenna composed of a large reflector and a feed array forms multi-beams. The feed cluster consists of a group of feed elements and each element should be optimized for the appropriate amplitude and phase. The optimization progress for amplitude and phase was performed by GO (Geometrical Optics) and PO (Physical Optics) method. The number of feed elements as well as the power level per element were also optimized to meet the required EIRP (Effective Isotropically Radiated Power). In conclusion, 30m-class reflector and twenty five elements for fifteen beams over Korean Peninsula were designed through the optimization process.

• Journal of Advanced Navigation Technology
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• v.27 no.4
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• pp.396-409
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• 2023

In the field of autonomous vehicles, where high accuracy and reliability are critical, various satellite navigation augmentation systems have been developed to improve system performance. These systems generate correction and integrity information based on measurements and navigation data collected from ground reference stations, enhancing user positioning accuracy. Thus, the performance of the system heavily relies on the deployment and spacing of reference stations. To construct an effective satellite navigation augmentation system, careful consideration must be given to the installation points of reference stations. This paper presents a user positioning performance modeling formula and proposes a method for selecting the installation points of new reference stations. The proposed method involves selecting a candidate group area that can optimize the user's positioning performance. By utilizing this method, the system's performance can be improved, ensuring high accuracy and reliability for autonomous vehicle applications.