• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.347-351
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• 2008

This study is concerned with the design of the communication based evaluation simulator for the development of the operational control algorithm for PRT(Personal Rapid Transit) system which has very short headway and requires accurate speed control of the vehicles to avoid the impact between the vehicles. The evaluation simulator is composed of central control system, vehicle control system, communication control system, AP for wireless communication, and monitoring system. For the mobile characteristics of the PRT vehicles wireless communication is employed for the transmission of the control and status information between the central control system and the vehicle control system. By using simple test operational control algorithm the effectiveness of the proposed evaluation simulator is shown.

• 항공우주시스템공학회지
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• 제5권2호
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• pp.8-11
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• 2011

The scope of this paper is to show a risk management plan including how to perform risk assessment and to make a mitigation plan aspects of the communication payload system development. According to system engineering management guide of DoD of USA and risk management plan of satellite communication system, risk assessment and mitigation plan of communication payload system were performed. In this paper, it is indicated the process of risk management and risk assessment procedures as well as mathematical model for risk assessment of DoD guide. It is shown how risk assessment and mitigation plan have implemented in communication payload system development through case study.

• 전기학회논문지
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• 제63권2호
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• pp.306-312
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• 2014

The ZigBee communication method, which is the most frequently applied to the LED lighting control system, has drawbacks of low-speed and low-capacity, and the communication failure possibility due to environmental influences is on the rise. Therefore, it is important to secure the communication reliability by applying an integrated interface with a wire-wireless dual-network. This paper developed a communication module, which has a platform converging and combining the ZigBee of USN environments with the PLC of power line communication environments, to implement a dualized communication interface system supporting the wire-wireless integrated protocol, and implemented a wire-wireless networking device and a control system software technology. As a result, it was automatically switched into the PLC communication within 4.4 seconds on average when there was an access failure in the ZigBee communication network, so a reliable communication network was built.

• 대한전자공학회논문지TC
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• 제48권7호
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• pp.35-40
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• 2011

u-TSN 환경에서 차량 단말기와 도로변에 설치되는 노변장치와의 통신은 서비스의 신속한 지원과 도로 교통정보의 실시간 확보를 위하여 교통시스템 구성 시에 매우 중요하다. 본 연구에서는 차량 통신 시스템의 성능 평가를 위한 V2I 혹은 I2V 통신 서비스 시나리오와 신속성과 정확성이 요구되는 긴급정보 전송을 위한 V2V 차량 간 통신 서비스 시나리오를 제시하였다. 그리고 실제 차량간 통신시스템을 구현한 후 제안된 통신 서비스 시나리오에 맞춰 차량통신 실험을 실시하는 방법으로 성능을 평가하였다. 실험결과 최적의 전송 모드 설정 조건을 도출하였으며, 도출된 결과는 안정적이고 효율적인 u-TSN 차량 통신시스템 개발에 적용가능하다.

• 한국전자통신학회논문지
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• 제14권1호
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• pp.127-136
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• 2019

전관방송 시스템은 위급상황 및 비상상황에서도 누구나 손쉬운 조작과 운영, 그리고 장비의 안정적 동작이 우선시되어야 한다. 본 논문에서는 전력선 통신 기반 전관방송 시스템 사용자에게 편리성과 효율성을 제공하기 위해, 전관방송 시스템의 PLC(Power Line Communication) 제어기와 UI(User Interface) 그리고 PLC 제어기와 PLC 스피커 간의 통신을 제어하기 위한 펌웨어를 구현하였고, 사용자가 컴퓨터 화면에서 손쉽게 사용할 수 있도록 UI 소프트웨어를 개발하였다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2007년도 춘계학술발표논문집
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• pp.66-68
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• 2007

본 논문에서는 CDMA 상향 중심주파수인 836.5MHz에서 단말기 송신 전력 제어를 위한 Schottky 다이오드 전력 검출기 기본 회로 구조를 제안한다 일반적인 다이오드의 비선형성에 의한 검파 출력의 선형성 개선과 낮은 입력 레벨의 출력 전압 감도 특성을 개선하기 위해서 낮은 검출기 입력 레벨에서의 임피던스 매칭을 한다 다이오드 패키지의 기생 성분을 고려한 시뮬레이션을 통하여 비교적 정확한 측정 결과를 예측할 수 있다. 본 논문의 전력 검출기의 전압 감도는 최대 0.1V의 비교적 우수한 특성을 보이며, -20dBm에서 +15dBm의 검출기 입력 대역에서 임피던스 매칭의 분석을 통하여 선형성의 뚜렷한 개선 효과를 얻는다. 또한 입력 주파수의 대역폭에 따른 매칭특성과 개선된 검파 출력 특성도 제시된다.

• 전기학회논문지
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• 제63권5호
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• pp.615-621
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• 2014

With development of electrical power system, the DC distribution system has been considered as a promising technology to be used in the future smart distribution system. Among the various components comprising the DC distribution system, the bi-directional DC/DC converter is one of the most important equipment to interconnect between main power system and various renewable resources such as photovoltaic power generation, wind power generation, and electrical vehicles. In this paper, a bi-directional DC/DC converter based on three-phases interleaved method which is effective to reduce ripple of input current and output voltage is modeled using ElectroMagnetic Transient Program(EMTP), and the verification of modeled bi-directional DC/DC converter is conducted.

• 한국위성정보통신학회논문지
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• 제7권3호
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• pp.75-77
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• 2012

최근 들어 다양한 이동 수단의 발전과 함께 철도 또한 많은 발전을 이루었다. 이렇게 발전된 철도 시스템과 더불어 정확한 철도 시스템 정보 전달을 위한 효율적인 통신시스템이 요구되었고, 이에 따라 철도 통신 시스템 또한 다양한 방식으로 발전했다. 철도 무선통신에서 페이딩의 영향을 최소화 하고 보다 효율적인 통신을 하기위해, 협력 통신방식이 제기되었다. 본 논문에서는 다양한 방식의 무선 통신방법 중 협력 전송 기법에 대해 소개하고, 이에 따른 채널 특성과 통신 예시 등을 소개할 것이다.

• 한국컴퓨터정보학회논문지
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• 제24권1호
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• pp.129-135
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• 2019

This paper is part of research and development for stand-alone solar system without commercial power supply. It implements firmware of controller for operation of stand-alone solar system by applying IoT technology and also develops communication modules that allow multiple solar lamps to send and receive data through wireless network. The controller of the developed stand-alone solar system can effectively charge the power generated by the solar module, taking into account the battery's charge and discharge characteristics. It also has the advantage of attaching wireless communication modules to solar lamp posts to establish wireless communication networks without incurring communication costs. In addition, by establishing IoT gateway middleware platform for each installation site, it forms a foundation to operate multiple solar lamp posts into multiple clusters. And, it is expected that the data collected in each cluster will be used to enable configuration and control of operational information, thereby inducing convenience and efficiency of remote operation and management.

• Current Optics and Photonics
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• 제6권1호
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• pp.23-31
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• 2022

Heterodyne efficiency is an indicator to evaluate the performance of space coherent laser communication systems. It is affected by signal light and local oscillator (LO) light amplitude, phase and polarization state. In this paper, based on the common heterodyne efficiency, a heterodyne efficiency model that can reflect polarization aberration of optical system is proposed. The heterodyne efficiency is analyzed when the signal light and the LO light are linearly polarized or circularly polarized. For a coherent communication optical system, when the incident signal light is right-circularly polarized light and the incident LO light is 45° linear polarized light. Based on the three-dimensional ray tracing theory and the heterodyne efficiency proposed in this paper, the change of polarization states and the distribution of heterodyne efficiency of the signal light and LO light influenced by the optical system's polarization aberration are analyzed. Analysis shows that the heterodyne efficiency model proposed in this paper can be used to evaluate coherent communication systems and reflect the influence of optical system polarization aberration.