• Electronics and Telecommunications Trends
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• v.25 no.6
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• pp.38-49
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• 2010

LTE 시스템에서 이동성 관리란 단말의 아이들 상태에서 수행되는 셀 재선택 기능과 단말의 통신중에 수행되는 핸드오버 기능을 모두 포함한다. 특히, 핸드오버 기술은 '통신중 끊김없는 서비스 보장'이라는 단순 기술형태에서 UMTS, HSPA 및 CDMA2000-1X 등 서로 다른 네트워크간의 컨버전스를 통하여 효과적인 트래픽 로드 분산 사업자의 초기 시설투자 부담 감소, 그리고 가입자의 자유로운 네트워크 선택 및 이에 따른 저렴한 요금 혜택 등 사업자와 가입자 모두에게 새로운 비즈니스 모델을 제공하는 복합 기술 형태로 진화되고 있다. 본 고에서는 LTE/LTE-Advanced 시스템에서 무선링크 측정, 타깃 셀 결정, 패킷 손실 관리, 타깃 셀로의 통신로 스위칭 등 일련의 고속 제어절차를 통하여 packet lossless-, timeless- 및 seamless- connectivity가 기능하도록 설계된 핸드오버 기술 전반을 무선 액세스 네트워크 관점에서 다룬다. 본 고에 사용된 정보 소스는 3GPP LTE 표준 문서에 기반한다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.30-32
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• 2000

최근 메타데이타의 주요 논쟁점으로 메타데이타의 표준화 문제가 등장하고 있다. 새로운 표준화 방향으로 인한 메타데이타의 확장성은 기존 메타데이타 관리 기법의 변화를 요구하게 되었다. 즉, 사용자의 질의에 대한 신속한 정보 제공과 동적인 자료의 일관성 있는 저장과 유지방 안을 필요로 한다. 이에 본 논문에서는 디지털 라이브러리 환경에서 메타데이타 속성을 정의하고, 이러한 요구사항을 만족하는 병행수행 제어 기법인 2VL(Two Version using the Latch)을 제안한다. 2VL은 래치를 사용하여 2버전을 유지함으로써 판독과 기록 연산간의 충돌로 인한 지연을 최소화하며 판독 연산에 있어서의 빠른 응답시간과 높은 최근성 반영율을 보인다.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.2
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• pp.8-14
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• 2012

"Throttle-by-Wire" is an electronic throttle system in which mechanical cables and hydraulics are replaced by a fieldbus network, electric motors and sensors. It is crucial for an electronic throttle to design a controller that can offer an accurate and fast reference tracking performance in the presence of nonlinearities, such as friction in the gearbox and "limp-home" nonlinearity. This paper presents a nonlinear dynamic inversion based control algorithm for electronic throttle systems. Using the proposed method, the specified control performance can be achieved by canceling inherent nonlinear characteristics of the electronic throttle system. The control performance is investigated through a set of simulation results.

• Proceedings of the KAIS Fall Conference
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• 2002.11a
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• pp.171-173
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• 2002

본 논문은 기존의 PC기반의 웹 서버를 이용한 것이 아닌 리눅스 기반의 임베디드 웹 서버를 제작하여 원격지 하드웨어의 제어와 감시를 구현했다. 리눅스는 2.4.1 버전을 ARM7 보드에 포팅했으며 웹 서버는 GPL(General Public License)규약인 Boa web server를 사용했다. 원격지 감시와 제어를 위해 Cirrus Logic의 ARM7 칩인 EP7312의 GPIO(General Purpose Inpout Output) B포트에 입력장치와 출력장치를 연결시켜 실험하였다. 리눅스 운영체제 환경에서의 GPIO 장치 드라이버를 작성하고 이를 구동시키는 응용프로그램은 리눅스용 C언어를 CGI프로그램화시켜 클라이언트 PC의 웹 브라우저에서 제어와 감시가 가능하게 했다. 이는 기존의 PC기반의 웹 서버를 사용하는 것 보다 비용절감이라는 장점이 있고 또한 운영체제 없이 구현되는 웹 서버보다는 응용 범위의 다양성과 개발기간 단축이라는 장점을 가지고 있다.

• Journal of IKEEE
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• v.21 no.2
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• pp.162-165
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• 2017

CAN (controller area network) is a standard real-time serial communication protocol, and it was developed to control various in-vehicle electronic modules. In this paper, a CAN controller was designed in Verilog HDL, based on CAN ver. 2.0A and 2.0B. The designed CAN controller was implemented in FPGA, and it was verified its operation by connecting commercial chips. Its size is about 7,800 gates when synthesized in 0.18um technology.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.6
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• pp.1-10
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• 2019

Traffic Signal Evaluation HILS is a system designed to evaluate a traffic signal system, and has a function of driving that simulates a real environment using a simulator that simulates a real traffic signal environment and an LCS that simulates a traffic signal controller. This study simulates the function of the traffic signal controller and is designed for design the LCS which is connected to the center system and the traffic simulator (VISSIM). The design of the LCS program uses a portable python language, and the code is designed in two versions running on Windows in the PC environment and unning on embedded environment, with a slight modification of the code. In this study, we analyzed the limitations of using LCS on Windows in PC environment and confirmed the ease of simulation Linux in embedded environment at large capacity.

• The KIPS Transactions:PartD
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• v.8D no.2
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• pp.132-144
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• 2001

The broadcast environment is asymmetric communication aspect that is typically much greater communication capacity available from server to clients than in the opposite direction. In addition, most of mobile computing systems only allow the generation of read-only transactions from mobile clients for retrieving different types of information such as stock data, traffic information and news updates. Since previous concurrency control protocols, however, do not consider such a particular characteristics, the performance degradation occurs when those schemes are applied to the broadcast environment having quite a high data contention. In this paper, we propose OCC/2VTS (Optimistic Concurrency Control based on 2-Version and TimeStamp) that is most appropriate for broadcast environment. OCC/2VTS lets each client process and commit query transactions for itself by using two version data in cache. If the values of appropriate data items are not changed twice by invalidation report after a query transaction starts, the query transaction is committed safely independent of commitment of update transactions. OCC/2VTS decreases the number of informing server for the purpose of commitment. Due to broadcasting the validation reports including updated recent values, it reduces the opportunity of requesting a recent data values of server as well. As a result, OCC/2VTS makes full use of the asymmetric bandwidth. It also improves transaction throughput by increasing the query transaction commit ratio as much as possible.

• Journal of Advanced Navigation Technology
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• v.11 no.1
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• pp.31-36
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• 2007

TCP (Transmission Control Protocol) is one of the protocols which are widely used from the Internet environments. Through the flow control of TCP, it could be increased efficiency for the loss and a re-transmission of data and the flow control become accomplished through window technique which puts the limit of size. By the flow control, TCP divided in various versions. In this paper, it is analyzed the simulation result which applies the error model in the Newreno which is an improved model of the representative Tahoe, Reno.

• Journal of IKEEE
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• v.20 no.3
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• pp.333-336
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• 2016

LIN (local interconnect network) is a standard low-speed serial communication protocol, and it was developed as an efficient sub-bus for automotive electronic modules. In this paper, a LIN controller was implemented in Verilog HDL, based on LIN ver. 2.2A. The implemented LIN controller was verified in FPGA, and it can be supplied as an IP to be integrated into SoC system. Its size is about 2,300 gates when synthesized in 0.18um technology.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.822-827
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• 2009

As research for URC robot to advance the robot system dissemination and pracical use becomes active, also interest for robot platform and standardization is increasing. However, URC robot middleware does not involve a convergence with IT. Although it seems to be a high connection between robots and IT, the existing middleware has not considered different environments, thus making convergence efforts difficult. The middleware should improve their functions in order to synchronize with IT and to interact through formatted messages. In this paper, we present the necessity of the formatted message in the development of URC platform. In addition, design of the message protocol for the convergence based on the analysis of RUPI, OPC and SECS-II.