• 산업기술연구
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• 제27권B호
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• pp.129-135
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• 2007

In this paper, an modal analysis based on the distribution of the electromagnetic fields on the UWB elliptical patch-slot antenna is presented. We designed the UWB antenna by iterating the dimensional parameters of the antenna as the traditional design method. Then the antenna was carefully analyzed using 3D E-M simulator. The result of the analysis shows that the slot antenna operates on a series of the multi-pole radiations based on TE modes matched to the system impedance. This result gives us an easier method to design the similar antennas, which is the impedance matching to the system impedance after once constructing a proper structure with a series of multi-mode resonances.

• Journal of Power Electronics
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• 제15권5호
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• pp.1318-1328
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• 2015

The photovoltaic (PV) power conditioning system for small-scale applications has gained significant interest in the past few decades. However, the standalone mode of operation has been rarely approached. This paper presents a two-stage multi-level micro-inverter topology that considers the different operation modes. A multi-output flyback converter provides both the DC-Link voltage balancing for the multi-level inverter side and maximum power point tracking control in grid connection mode in the PV stage. A modified H-bridge multi-level inverter topology is included for the AC output stage. The multi-level inverter lowers the total harmonic distortion and overall ratings of the power semiconductor switches. The proposed micro-inverter topology can help to decrease the size and cost of the PV system. Transient analysis and controller design of this micro-inverter have been proposed for stand-alone and grid-connected modes. Finally, the system performance was verified using a 120 W hardware prototype.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2005년도 종합학술발표회 논문집 Vol.15 No.1
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• pp.23-28
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• 2005

An airborne radar is an essential aviation electronic system of the helicopter to perform various missions in all-weather environments. This paper presents the results of the design and implementation of the airborne pulse doppler radar signal processor using high multi-DSP for the multi-function radar capability such as short-range, midium-range, and long-range depending on the mission of the vehicle. Particularly, the radar signal processor is developed using two DSP boards in parallel for the various radar signal processing algorithm. The key algorithms include LFM chirp waveform-based pulse compression, MTI clutter filter, MTD processor, adaptive CFAR, and clutter map. Especially airborne moving clutter Doppler spectrum compensation algorithm such as TACCAR is implemented for the multi-mode airborne radar system. The test results shows the good Doppler spectral separation for the clutter and the moving target in the flight test environment using helicopter.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.217-224
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• 2005

Generally, the underwater flight vehicle (UFV) depth control system operates with the following problems: it is a multi-input multi-output (MIMO) system because the UFV contains both pitch and depth angle variables as well as multiple control planes, it requires robustness because of the possibility that it may encounter uncertainties such as parameter variations and disturbances, it requires a continuous control input because the system that has reduced power consumption and acoustic noise is more practical, and further, it has the speed dependency of controller parameters because the control forces of control planes depend on the operating speed. To solve these problems, an adaptive fuzzy sliding mode controller (AFSMC), which is based on the decomposition method using expert knowledge in the UFV depth control and utilizes a fuzzy basis function expansion (FBFE) and a proportional integral augmented sliding signal, is proposed. To verify the performance of the AFSMC, UFV depth control is performed. Simulation results show that the AFSMC solves all problems experienced in the UFV depth control system online.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.278-281
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• 1988

This paper realizes the multi-output truncated difference circuits using current mode CMOS, and presents the algorithm designing multi - valued logic functions of a given multivalued truth tables. This algorithm divides the discrete valued functions and the interval functions, and transforms them into the truncated difference functions. The transformed functions are realized by current mode CMOS. The technique presented here is applied to MOD4 addition circuit and GF(4) multiplication circuit.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2009년도 춘계학술대회
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• pp.135-138
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• 2009

Cylindrical monopole antenna is one of most promising candidates for multi-band applications such as PCS, WLAN, DMB, and UWB wireless services. In this research, we analyze the current distributions of operating modes for a cylindrical double-resonant monopole antenna. Two modes, the standing wave mode in a lower band and the traveling wave mode in a higher band, are identified from CST software simulations. Finally, design formulas are derived form the simulation results.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2000년도 학술발표회 발표논문집
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• pp.226-232
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• 2000

The design of agricultural facilities is the consistent activities, which systematically analyze all the actual conditions, design the unit structures, and improve the faming environment through efficient organization of the unit facility. The design of agricultural facilities is composed of site study, preliminary design, primary design, and detail design. Integrated design system can manage and process the information created by and used in all steps of design process. Formal data models of these design activities are important conceptual steps in development of integrated design system. However, most of existing models are not available for agricultural facilities. To support efficiently developing the integrated design system of agricultural facilities, we have developed the Multi-Layered Primitive-Composite mode I through object-oriented analysis of agricultural facilities. The MPC model not only satisfies the characteristics of agricultural facility, such as variety, coupling, informal data, but also improves abilities of integrated design system such as extensibility, flexibility, and granularity. The paper presents a formal definition of the MPC model.

• 한국통신학회논문지
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• 제37C권12호
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• pp.1281-1288
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• 2012

본 논문은 재난 정보를 다양한 모바일방송 규격에 따라 인코딩 및 송출, 수신 및 디코딩하는 멀티모드 방송용 EWS 송 수신 시스템의 설계 및 구현 방법을 제안한다. 제안한 시스템은 전 세계 모바일 방송 표준 중 T-DMB, DVB-H, ISDB-T와 디지털 라디오 규격인 DRM을 지원하며, 각각의 방송 규격에 따라 재난 정보를 인코딩하는 송출부와 각 표준에 따른 RF 방송 신호를 수신 및 디코딩하는 수신부 형태로 구성된다. 제안한 멀티모드 방송용 EWS 송신시스템은 단일 시스템상에서 각각의 방송규격으로 EWS 재난 데이터 생성하고 상용 방송 송출 장비규격에 만족하는 채널 인터페이스를 통해 재난정보가 송출 가능하며 수신 시스템에서는 단일 H/W에서 해당 모드의 재난 정보를 수신, 디코딩하여 단말기 화면에 표출한다. 제안된 시스템은 실시간으로 각 모드별 상용 방송장비에서 송출되는 RF 신호를 수신하여 문자기반의 재난 정보를 표출하는 정합 검증 과정을 통해 정상동작 결과를 제시한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.680-683
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• 2001

The output characteristics of step-down piezoelectric transformer is changed by a structure of layers. In this paper, we simulated output characteristics of multi-layer piezoelectric transformers with variation of output layers. Also, fabricated piezoelectric transformers were compared with simulated data. From simulated piezoelectric transformers, the output voltage decreased with increasing number of layers. From these results, piezoelectric transformers were made and the output electrical power of the transformers was measured at resonance frequency and at other frequency. The electrical power of transformers was measured on each transformer's resonance mode. However, measured value of 12-layed transformer's output power was smaller than that of 6-layered transformer's one. It is supposed that internal capacitance and reactance of the piezoelectric transformer's were effected in this result. Therefore we need to connect other road resistance and capacitance in output circuit, in order to increase electrical power of transformers.

• 한국전자파학회논문지
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• 제26권2호
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• pp.158-164
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• 2015

OTM(On-The-Move) 위성통신 시스템은 차량에 탑재되어 고속 주행하거나 요동이 심한 지역을 주행하면서 위성 통신 링크를 안정적으로 유지하여야 한다. 따라서 열악한 환경에서도 정밀 추적이 가능하고, 차량에 탑재할 수 있도록 소형/경량화된 위성 추적 시스템이 필요하다. 2개의 슬롯(slot)으로 구성된 단일 모드 커플러를 사용하여, 원형 편파 특성을 이용하여 하나의 물리적 채널로 상하, 좌우 2개의 차신호를 동시에 비콘 수신기까지 전달하는 방안을 제안하고, 측정된 추적 오차신호를 제시한다.