• Title/Summary/Keyword: time-synchronization

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A Development of Integration System for Distributed Geospatial Data of Homeland (분산환경 국토공간정보의 통합 시스템 구축방안에 관한 연구)

  • Joo, Young-Eun;Choi, Joon-Seok;Lee, Jin-Duk;Han, Seung-Hee
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2010.04a
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    • pp.121-123
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    • 2010
  • Currently different local governments and research institutes have established and using DB for each purposes on the heterogeneous database. Normally physical unification method is used in order to unify this geospatial database, but this takes too much time and resources and require periodic renewal and synchronization. Therefore, this research would like to present a logical integrated unification method based on attribute information of heterogeneous database, and a system design and construction method, in order to subjugate inefficiencies from the physical unification method. Through this a system that could supply user customized geospatial database was established and verified the functionality using the road data of an actual region.

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Design and Implementation of CAN IP using FPGA (FPGA를 이용한 CAN 통신 IP 설계 및 구현)

  • Son, Yeseul;Park, Jungkeun;Kang, Taesam
    • Journal of Institute of Control, Robotics and Systems
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    • v.22 no.8
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    • pp.671-677
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    • 2016
  • A Controller Area Network (CAN) is a serial communication protocol that is highly reliable and efficient in many aspects, such as wiring cost and space, system flexibility, and network maintenance. Therefore, it is chosen for the communication protocol between a single chip controller based on Field Programmable Gate Array (FPGA) and peripheral devices. In this paper, the design and implementation of CAN IP, which is written in VHSIC Hardware Description Language (VHDL), is presented. The implemented CAN IP is based on the CAN 2.0A specification. The CAN IP consists of three processes: clock generator, bit timing, and bit streaming. The clock generator process generates a time quantum clock. The bit timing process does synchronization, receives bits from the Rx port, and transmits bits to the Tx port. The bit streaming process generates a bit stream, which is made from a message received from a micro controller subsystem, receives a bit stream from the bit timing process, and handles errors depending on the state of the CAN node and CAN message fields. The implemented CAN IP is synthesized and downloaded into SmartFusion FPGA. Simulations using ModelSim and chip test results show that the implemented CAN IP conforms to the CAN 2.0A specification.

Respondence Between Electrochemicl Fluctuations and Phenomenon for Localized Corrosion of Less-Noble Metals

  • Itoi, Yasuhiko;Take, Seisho;Tsuru, Tooru
    • Corrosion Science and Technology
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    • v.7 no.1
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    • pp.35-39
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    • 2008
  • We have been studying application of electrochemical noise (Fluctuation) analysis for localized corrosion. Foils of Zinc, Aluminum and Magnesium were used as specimens for electrochemical cell simulating localized corrosion. These specimens were dipped in sodium chloride solutions adjusted to each exponent of Hydrogen ion concentration (pH) condition of 5.5, 10, 12 respectively. Time variations of potential and current were measured in those solutions, and simultaneously the surfaces of specimens were observed using microscope with television monitor. Two types of electrochemical cells were arranged for experiments simulated localized corrosion. The fluctuations on trendy component of short-circuited potential and short-circuited current were appeared in synchronization. It was seemed that these fluctuations result from hydrogen evolution on the aluminum active site in the crevice from the microscopic observation. In the case of zinc and magnesium, fluctuations appeared on the trendy component of the corrosion potential. Two types fluctuation were detected. First one is the fluctuation varied periodically. The second one is the random fluctuation. It was seemed that these fluctuations result from generation of corrosion products and hydrogen evolution on the active site in the crevice of zinc and magnesium from the microscopic observation.

Implementation of A Networked Collaboration Engine for Virtual Engineering of Tilting Train (틸팅차량의 네트워크 협업 엔진 구현)

  • Chung, Yoo-Jin;Han, Seong-Ho;Song, Yong-Soo
    • Journal of the Korean Society of Systems Engineering
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    • v.2 no.2
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    • pp.45-50
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    • 2006
  • Tilting technology is to tilt the train on the curve in order to minimize centrifugal force to passengers and to improve the speed within the limits of passenger's comfort and safety. According to reports from other countries, there is 15~30% speed improvement compared to the conventional trains. Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. The progress of 3D computer graphics enabled collaborative applications with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of the Share collaboration engine which is for collaboration applications based on a distributed virtual environment. The Share collaboration engine proposes a new Share network architecture for management of participants, and it provides some synchronization methods for 3D objects in virtual collaboration. TTX_PDM is an experimental application that tries to prevent wastes of human, material and time resources in networked virtual collaboration.

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Development of Consistency Algorithm for VOD Streaming Server Data (VOD 스트리밍 서버 데이터를 위한 일치성 보장 알고리즘 개발)

  • Jang Seung-Ju
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.43 no.5 s.311
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    • pp.8-16
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    • 2006
  • This paper proposes and implements consistency algorithm that is serviced streaming data efficiently in VOD system. The media data is loaded into each node by Round Robin method. The barrier mechanism is changed into the minimum data factor(SH, GOP) of media data in this paper. In addition in order to fast media data service, the additional features are implemented in the consistency algorithm. Additional feature of the consistency algorithm is added. First, time synchronization algorithm is added the suggested consistency algorithm. Second, the prepaging mechanism supports efficient buffering service. I experimented the suggested consistency algorithm two DSM systems. The performance is good due to the last barrier algorithm.

A high-resolution synchronous mirror delay using successive approximation register (연속 근사 레지스터를 이용한 고정밀도 동기 미러 지연 소자)

  • 성기혁;김이섭
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.41 no.10
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    • pp.63-68
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    • 2004
  • A high-resolution synchronous mirror delay (SMD) is proposed in order to reduce the clock skew between the external clock and the infernal clock of a chip. The proposed SMD reduces the clock skew in two steps. Coarse locking is achieved by the SMD. Fine locking is achieved by the successive approximation register-controlled DLL. The total locking time is 10 clock cycles. Simulation results show that the proposed SMD operates with 50psec clock skew at 182MHz and consumes 17.5mW at 3.3V supply voltage in a 0.35 um 1-poly 4-metal CMOS technology.

Consideration of Performance in Synchronization of Frequency Hopping / Code Division Multiple Access System (FH/CDMA를 위한 동기화 기술의 성능 고찰)

  • 이승대;방성일;진년강
    • The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
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    • v.5 no.4
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    • pp.18-29
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    • 1994
  • In this paper, the performance of stepped serial search scheme and matched filter scheme for code acqusition in FH / CDMA are evaluated under land mobile radio communication channel environments. And delay lock loop scheme is used as code tracking system. As the results for code acquisition system, it is shown that the performance of stepped searial scheme is superior to matched filter scheme, because system complexity is reduced and system performance is improved by increasing the hopping frequency not to substitute for special hardware. Also, it is shown that its performance is improved under Rayleigh/ Rician fading environments. As the results for code tracking system, it is found that mean hold time is increased due to the increase of the number of lock state and hopping frequency, M.

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Proposal and Implementation on Non-Repudiation of Origin for DNP3 (DNP3에 적합한 발신 부인 방지 기법 제안과 그 구현)

  • Yu, Ki-Soon;Song, Kyoung-Young;Jang, Min-Ho
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.40 no.5
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    • pp.815-825
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    • 2015
  • DNP3(Distributed Network Protocol) is one of the most representative protocols which is used in SCADA(Supervisory Control and Data Acquisition) system. IEC 62351 is listing the integrity, confidentiality, availability and non-repudiation or accountability as the security requirement. However, IEEE Std. 1815 that is DNP3 standards does not define a mechanism for non-repudiation or accountability. In this paper, we propose a non-repudiation of origin technique about the sender of critical ASDU and implement the proposed scheme using software such as OpenSSL and SCADA source code library.

A Research on EEG Synchronization of Movement Cognition for Brain Computer Interface (뇌 컴퓨터 인터페이스를 위한 뇌파와 동작 인지와의 동기화에 관한 연구)

  • Whang, Min-Cheol;Kim, Kyu-Tae;Goh, Sang-Tae;Jeong, Byung-Yong
    • Journal of the Ergonomics Society of Korea
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    • v.26 no.2
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    • pp.167-171
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    • 2007
  • Brain computer interface is the technology of interface for next generation. Recently, user intention has been tried to be recognized for interfacing a computer. EEG plays important role in developing practical application in this area. Much research has focused on extracting EEG commander generated by human movement. ERD/ERS has generally accepted as important EEG parameters for prediction of human movement. However, There has been difference between initial movement indicated by ERD/ERS and real movement. Therefore, this study was to determine the time differences for brain interface by ERD/ERS. Five university students performed ten repetitive movements. ERD/ERS was determined according to movement execution and the significant pattern showed the difference between movement execution and movement indication of ERD/ERS.

The performance improvement of new correlator architecture in vehicles navigation system (차량요 항법시스템 기반의 새로운 correlator 구조에 따른 성능 향상에 관한 연구)

  • Park, Chi-Ho;Oh, Young-Hwan
    • Journal of the Institute of Electronics Engineers of Korea TC
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    • v.44 no.12
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    • pp.44-53
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    • 2007
  • In this paper, we focus on the developments of complex location awareness algorithms for real-time location based service and precise/stable localization in the outdoor. In the case of using galileo satellite system along with GPS, several error factor such as the ionosphere can be reduced for an increment of used frequency and visible satellites. Therefore, localization estimation error is no longer having problems with location awareness. But, chips synchronization error induces the error of acquisition and tracking, and the performance of receiver can be decreased. In order to solve this problem, this paper proposes a correlator for performance improvement of receiver in the precise localization.