• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.7
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• pp.995-1002
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• 2013

In this paper, an effort has been made to design a Real-time Ship Management System where the status of a ship and its surrounding are constantly monitored and recorded at the base station. Proprietary system message based on overhead and checksum encapsulation has been designed to facilitate the communication. Software encoder and decoder are developed independently for each communication device attached to the system to process the proprietary system message into format by device standard. In addition, few configurations are designed to determine the method of updating the ship status message to the base station, which could be remotely chosen by the administrator.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.22-24
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• 2019

e-Navigation의 핵심 통신 시스템으로 사용되어질 VDES는 2015년 ITU-R M.2092-0가 발행된 이후로 2020년 개정된 표준을 발행하기 위해 IALA를 중심으로 활발히 기술규격에 대한 개발이 진행되고 있다. 우리나라도 한국형 e-Navigation사업을 통해 VDES의 기술 개발과 표준화에 기여하고 있다. 본 논문에서는 IALA G1139 Ed. 1을 기반으로 하여 개발된 VDES 해안국 장비의 제어부와 내장소프트웨어인 프로토콜처리 소프트웨어의 설계 및 구현에 대해서 기술하고자 한다. 먼저, IALA G1139에서 기술하고 있는 VDES에 대한 개요에 대해서 설명하고 VDES 해안국 장비의 설계 내용과 시험결과에 대해서 언급한다. VDES 해안국 제작을 통해 e-Navigation에서 요구하는 대용량 데이터 전송과 같은 통신 요구사항을 지원할 수 있을 것으로 확인 하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.427-429
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• 2013

DGPS Reference Station the national infrastructure generates the DGPS correction information for Differential GPS. Currently, South Korea operates the software based DGPS reference station using the next generation DGPS architecture in order that upgrade the hardware based DGPS reference station. However the software based DGPS reference station proposed by USCG has not changed just a form of its structure but intimate architecture. Accordingly, It can't strengthen the advantages of software based architecture. In this paper, I will propose a new software architecture design that is integrated with DGPS reference station and integrity monitor. This architecture is more simple than existing one so can use the maritime DGPS reference station which is required more simple structure.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.7
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• pp.4554-4561
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• 2014

In recent years, several paradigms have been identified to simplify the design of fault-tolerant distributed applications in a conventional static system. Leader Election is among the most noticeable, particularly because it is closely related to group communication, which provides a powerful basis for implementing active replications among other uses. On the other hand, despite its usefulness, to our knowledge, no study has focused on this problem in a mobile computing environment. The aim of this paper was to propose an algorithm for the leader election protocol in a fixed station based wireless networks environment. The election algorithm is much more efficient than other election algorithms in terms of the fault tolerance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.1A
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• pp.1-7
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• 2011

Cell Capacity and cell layout are strongly dependent on the up-link interference caused by out-of-cell mobiles. Accurate prediction of the propagation path loss from out-of-cell mobiles is essential to achieve system designs that minimize the infrastructure required for a given quality of service (QOS). Less accurate predictions can be expected to yield designs requiring the use of a greater number of base stations. In order to quantify the dependence of infrastructure on prediction accuracy, this paper considers the cellular systems, LOS (line of sight) cells along a road or highway.

• Aerospace Engineering and Technology
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• v.13 no.2
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• pp.142-149
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• 2014

After launch of Low Earth Orbit(LEO) satellite, Initial Activation Checkout(IAC) and Calibration and Validation(Cal & Val) procedure are performed prior to enter normal operation phase. During normal operation phase, most of the time is allocated for mission operation except following up measures to anomaly and orbit maintenance. Since mission operation capability is key indicator for success of LEO satellite program and consistent with promotion purpose of LEO satellite program, reliability should be ensured by conducting through test. In order to ensure reliability by examining the role of LEO satellite and ground station during ground test phase, realistic test scenario that is similar to actual operation conditions should be created, and test that aims to verify full mission cycle should be performed by transmitting created command and receiving image and telemetry data. This paper describes the test design and result. Consideration items for test design are described in detail and result of designed test items are summarized.

• Electronics and Telecommunications Trends
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• v.21 no.1 s.97
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• pp.94-103
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• 2006

기지국/단말 모뎀 검증 장치(MAT)는 기지국(AS) 모뎀, 단말(UE) 모뎀으로 구성되는 초고속 무선 전송 시스템(HM20) MIMO 구조 기지국/단말 모뎀의 자체 기능 검증과 기지국 모뎀과 단말 모뎀의 연동 시험시 오류 원인을 분석하기 위하여 상향 링크(UL)와 하향 링크(DL)의 송. 수신단의 정합부에 디지털 및 아날로그 정합을 이용하여 기지국모뎀과 단말 모뎀이 정상적으로 동작하는지를 시험하게 된다. 모뎀 검증 장치(MAT)는 상향 링크 신호는 단말 변조기의 송신 신호 수신과 기지국 복조기에 변조 신호를 송신, 하향 링크 신호는 기지국 변조기의 송신 신호 수신, 단말 복조기에 변조 신호를 송신하는 기능을 수행하여 상향 링크 신호와 하향 링크 신호를 시험 및 분석하는 기능을 수행한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.2B
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• pp.145-150
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• 2002

This paper presents an implementation methodology of unified PCS base station system which, is capable of providing PCS services for 3 PCS carriers concurrently. We have built up an unified PCS BTS using a unification module, which is consisted of a multi-channel combiner, duplexer, LNA, power divider, feeder line, and a common set of antennas. PCS unification module is featured with wide-band and high power handling capability and electrical characteristics like insertion loss, isolation have been greatly improved. It was shown that performance of the system in terms of Ec/Io and mobile receive power within the total 30MHz PCS frequency range is uniformly acceptable and measured signal quality and coverage are equivalent to that of the individual PCS base station.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.124-127
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• 2005

국내에서는 언제 어디서나 휴대용 단말을 이용하여 저렴한 요금으로 고속의 무선인터넷을 사용할 수 있는 휴대인터넷 서비스를 2006년부터 서비스 할 계획이다. 앞으로 서비스 될 WiBro 휴대인터넷 서비스 방식은 기존 이동통신 방식과 달리 RF 송신 주파수와 수신 주파수가 동일한 TDD (time division duplexing) 방식을 사용한다. WiBro 무선통신 기지국 장비에 있어서도 기존 CDMA 이동통신 기지국 장비에서와 마찬가지로 RF Power Amplifier (PA)가 매우 고가의 핵심 부품이라 할 수 있다. 물론, 기존 FDD (frequency division duplexing) 방식의 CDMA 기지국 PA와 달리 WiBro용 기지국 PA는 TDD 신호를 처리할 수 있는 새로운 기술을 필요로 한다. TDD 방식인 WiBro 기지국용으로 사용할 수 있는 새로운 2.3 GHz 42 W PA를 설계, 제작한 결과를 본 논문에서는 발표하고자 한다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.282-288
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• 2014

The DGPS reference station is a national infrastructure generating GPS correctional information and transmitting the signal for Differential GPS. Currently, Korea has applied and operated the software-based DGPS reference station as a standard of the next generation proposed by the USCG in order to improve the hardware-based DGPS reference system. However, software-based DGPS reference station proposed by USCG was changed in software method, only for form. There is no advantage to changing software-based because the most critical part of architecture has not been improved. In this paper, we have designed a new software-based marine DGPS station architecture that a reference station software and a monitor station were integrated. The new marine DGPS station architecture based on software is a more simplified structure than it used to be and can be utilized in the DGPS reference station.