주파수 공유기법을 적용한 RF 송수신기에 대한 연구

김기중,김종성,배문관,Kim, Ki-Jung,Kim, Jong-Sung,Bae, Moon-Kwan 한국전자통신학회 2015 한국전자통신학회 논문지 Vol.10 No.12

In this paper Communication data link equipment on a high speed-hopping method to use the frequency resources efficiently for the frequency environment is introduced such as sensing techniques, using the same frequency band by using the received two-channel technique and the receive filter bank unit applied to be shared with other equipment such as radar and so on. The real-time measurement and analysis were operated for measurement the frequency environment of the operating band in advance. and primarily equipment to develop is analyzed how the interference effect to the radar minimize the operation of radar equipment. In reverse, to use the same frequency band the methods such as frequency sharing techniques are presented in this paper. Finally, by design of the main items of the RF transceiver NF, transmission output, and a simulation of the IMD, such as whether the key is verified prior to meet specifications.

GaAs MMIC를 이용한 X대역용 25W급 전력증폭모듈의 설계 및 구현에 대한 연구

김기중,김봉수,Kim, Ki-Jung,Kim, Bong-Soo 한국전자통신학회 2014 한국전자통신학회 논문지 Vol.9 No.11

To be used in a transmitter of a satellite transponder of this paper, X band 25W power amplifier module, a part constituting of high-power amplifier is transmitted to the equipment for transmitting to geostationary communications satellites(36,000Km distance). PAM consisted a total of four power amplifier module has a high output characteristic of the high-output amplifier is used in the ground station. Used in conjunction with the structured type power amplifier module is composed of Serial Combining Structure. This PAM(Power Amplifier Module) configured by combining the circuit with the power amplifier, 10 MMIC chips and the Al2O3 thin film substrate using a Hybrid Technique of power amplifier module, was implemented at X band PAM(Power Amplifier Module) of 25W grade.

디지털위성중계기 시스템 성능 분석 및 구현

김기중,서학금,Kim, Ki-Jung,Seo, Hak Geum 한국전자통신학회 2014 한국전자통신학회 논문지 Vol.9 No.4

This study introduces about the analysis, verification and implementation of Digital Communication Satellite transponder. Through the pre-performance analysis of each component by the circuit level simulation, each component's performance was checked whether satisfying the specifications. When each of the components was connected in order, System's performances were evaluated through system harmonic balanced simulation whether satisfying the specifications. Through pre-analysis of the system performance, specification of each component was defined. On the basis of that specification, Components which comprise the Digital Communication Satellite repeater were manufactured, and finally, the overall system performance check was made by integrating the components of Digital Communication Satellite transponder.

다중포인트 통신 프로토콜을 지원하는 디지털 화재 방지 모니터링 시스템 구현에 관한 연구

김기중,Kim, Ki-Jung 한국전자통신학회 2012 한국전자통신학회 논문지 Vol.7 No.6

In this paper, we investigated an implementation of anti-fire monitoring system based on the RS-485 communication to support local area coverage within a range of 1 Km range. We developed a Multi Point Communication Protocol supporting input/output information processing and control up to 8128 terminal check points, which provides an interface between the anti-fire monitoring system receiver and multiplex transponders. Additionally, a multiplex transponders controller has been designed for the implemented system to comply with the government regulation on fire protection, especially to monitor, report and control 1016 terminal check points within the time limit.

정원줄기세포의 이종간 이식을 위한 효율적인 수여(Recipient) 생쥐 생산 기법 개발

김기중 ( Ki Jung Kim ),임한 ( Han Lim ),왕종현 ( Jong Hyun Wang ),김병각 ( Byung Gak Kim ),이용안 ( Yong An Lee ),김방진 ( Bang Jin Kim ),김용희 ( Yong Hee Kim ),홍영호 ( Yeong Ho Hong ),김근배 ( Geun Bae Kim ),류범용 ( Buom Yong 한국조직공학·재생의학회 2013 조직공학과 재생의학 Vol.10 No.1s

Spermatogonial xenotransplantation assay provides access to the several species germline and has been used in experimental animal models to study stem cell biology and germline development. To make the xenotransplantation technology more extensively accessible, it is require development of recipient preparation protocols. Therefore, we propose an optimal method for preparation of athymic nude recipient with busulfan treatment. To investigate the optimal concentration of busulfan treatment, athymic nude mice (6~8 weeks old) were intraperitoneally injected with different concentrations of busulfan (0, 15, 25, 35 and 45 mg/kg). 6~8 weeks after busulfan treatment, testicular weight was significantly lower in 45 mg/kg treated group than the other groups. And the percentage of spermatogenic tubule was significantly reduced in 45 mg/kg of busulfan treated recipient testis. Also we compared the gene expression level of sertoli-cell-derived growth factor, glial-cell-line-derived neurotrophic factor (GDNF) as a potential measure of niche function. Relative to the other experimental groups, 45 mg/kg busulfan treated recipient testis showed higher GDNF expression. Next, to find out the appropriate time to transplantation after treated with busulfan (45 mg/kg), the rat testicular donor cells were transplanted into recipient testis at 2, 4, 6 and 8 weeks after treated with busulfan. Analysis of recipient mice revealed that transplantation of donor cells on 6 weeks after busulfan treatment was the most effective time to support high level of donor stem cell engraftment. In this study, we provide an optimum experimental condition for preparation of recipient mouse model system for xenotransplantation. Also, our data could contribute to recipient preparation in other species.

축소형 항공기 모델의 레이다 단면적 분석 및 측정에 대한 연구

김기중(Ki-Jung Kim) 한국전자통신학회 2020 한국전자통신학회 논문지 Vol.15 No.6

This study is a study on the analysis and measurement of the radar cross-sectional area of a miniature aircraft. Radar cross-sectional area for miniature aircraft in advance were analyzed using an electromagnetic analysis tool, and an actual miniature aircraft was manufactured and measured in an anechoic chamber. When measuring, the old model was used as reference data for RCS(radar cross section) characteristics and applied to the test result data of the actual reduced model. The measurement method improved the accuracy of the measurement by applying time gating to remove the influence on the components scattered inside the anechoic chamber. The RCS test results of the reduced model showed relatively high RCS characteristics in the microwave band, as the previous analysis results. In the future, we plan to utilize the method of RCS analysis and measurement for the target of the radar in the VHF(Very High Frequency)/UHF(Ultra High Frequency) band with a relatively large wavelength.

초단파 대역의 표적 반사 신호 시험 및 분석에 대한 연구

김기중(Ki-Jung Kim) 한국전자통신학회 2020 한국전자통신학회 논문지 Vol.15 No.5

This study is a study on the characteristics and analysis of the reflected signals about the target in the VHF band. In advance, the RCS(Radar Cross Section) characteristics of the target were analyzed by using the CST electromagnetic analysis tool, and the target was detected by using the Bi-Static method, and the change in the signal-to-noise ratio was tested. The test results show similar results with no significant fluctuations in the signal-to-noise ratio characteristics for the detection of signals reflected on the target, such as the results for RCS analysis according to the pre-incidence angle. In the future, this study will be used for RCS analysis of the targets and target detection of Radar in VHF/UHF band with relatively large wavelength compared to the X band.

수중 양식어류 계수 추정을 위한 Echo-Sounder 개발에 관한 연구

김기중(Ki-Jung Kim),선휘준(Hwi-Joon Seon),이영석(Yeong-Seok Lee) 산업기술교육훈련학회 2020 산업기술연구논문지 (JITR) Vol.25 No.4

An acoustic echo-sounder is an effective piece of equipment used to detect underwater targets by emitting ultrasonic waves and receiving reflections from the targets. In this study, we present a new compact echo-sounder and implement a new signal processing algorithm to estimate fish populations. Experimental results demonstrate that our device has comparable scattering strength and signal patterns to those of a popular acoustic echo-sounder (Simrad, EK-15). Because our method accurately estimates fish abundance, the method is reliable for making fish-management decisions.

공동구용 수직구 접속부 보강/차수 장치 시제품 개발

김기중 ( Kim Ki-jung ),강지훈 ( Kang Ji-hoon ) 한국구조물진단유지관리공학회 2019 한국구조물진단유지관리공학회 학술발표회 논문집 Vol.23 No.2

공동구용 수직구 접속부는 부등침하 발생, 지하수위 저감, 지진 등 동하중에 의한 상대변위 발생 등의 문제점이 야기되고 있다. 현재 국내에서는 수직구 접속부 시공 시 지반안정화를 위한 각종 공법을 적용하고 있으나, 접속부에 대해 직접적인 보강/차수 기술 적용은 전무한 실정이다. 따라서 본 연구에서는 공동구용 수직구 접속부에서 야기되고 있는 문제점을 상쇄할 수 있는 공동구용 수직구 접속부 보강/차수 장치 시제품을 개발하였다.

SRM형 BLDC 모터의 소음 제어 문제 및 저소음 초기 구동 구현에 관한 연구

김기중(Ki-Jung Kim),임형규(Hyung-Kyu Im),이창기(Chang-Ki Lee) 한국엔터테인먼트산업학회 2014 한국엔터테인먼트산업학회논문지 Vol.8 No.3

Blushes are known to generate unwanted nano particles of dust and harm elements in various electro-mechanical home appliances. Subsequently, the blushless type is proposed as an eco-friendly alternative to replace the brushes, and the expensive magnetized rotor of the Blush-less DC (BLDC) is to be replaced in SRM, which requires complex control not to overflow the switching current the system within a budget. A know weak point of the SRM-BLDC is that there is a strong starting noise due to the initial slipping of the rotator and subsequent mechanical vibration. This paper introduces an approach to implement an cost-effective starting noise controller for high-speed rotation control, employing Switched Reluctance Motor (SRM) BLDC motor.