• Title/Summary/Keyword: Synchronization Network

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Modeling of an isolated intersection using Petri Network

  • 김성호
    • Journal of Korean Society of Transportation
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    • v.12 no.3
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    • pp.49-64
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    • 1994
  • The development of a mathematical modular framework based on Petri Network theory to model a traffic network is the subject of this paper. Traffic intersections are the primitive elements of a transportation network and are characterized as event driven and asynchronous systems. Petri network have been utilized to model these discrete event systems; further analysis of their structure can reveal information relevant to the concurrency, parallelism, synchronization, and deadlock avoidance issuse. The Petri-net based model of a generic traffic junction is presented. These modular networks are effective in synchronizing their components and can be used for modeling purposes of an asynchronous large scale transportation system. The derived model is suitable for simulations on a multiprocessor computer since its program execution safety is secured. The software pseudocode for simulating a transportation network model on a multiprocessor system is presented.

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A Study on Time Synchronization Method for Analyzing the Network Performance of Remote Control System (원격운용 시스템의 네트워크 성능분석을 위한 시간동기화 방안에 관한 연구)

  • Yang, DongWon;Kim, Namgon;Kim, Dojong
    • Journal of IKEEE
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    • v.26 no.2
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    • pp.141-149
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    • 2022
  • With the development of artificial intelligence and unmanned technologies, the remote surveillance/autonomous driving systems have been actively researched. For an effective performance analysis of the developed remote control system, it is important to record the data of it in real time. In addition, in order to analyze the performance between the control system and the remote system, the recorded data from them should be synchronized with time. In this paper we proposed a novel time synchronization method for the remote control system. The proposed remote control system satisfies the time difference of the recorded data within 1 ms, and we can reduce the time difference by using a CPU shielding and affinity setting. The performance of the proposed method was proved through various network data storage experiments. And the experiments confirmed that the proposed method can be applied to recording devices of unmanned ground vehicles and control vehicles. The proposed method will be used as a method for analyzing network data of UGV-R (Unmanned Ground Vehicle - Reconnaissance).

Low Power MAC Protocol Design for Wireless Sensor Networks using Recursive Estimation Methods (회귀적 추정 방식을 이용한 무선 센서 네트워크용 저전력 MAC 프로토콜)

  • Pak, Wooguil
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.39C no.3
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    • pp.239-246
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    • 2014
  • In the context of wireless sensor networks, one of major issues is energy conservation. For low power communication, by utilizing our experimental results for the relation between clock drift and synchronization interval, we designed a new protocol which can support a wide range of duty cycles for applications with very low traffic rate and insensitive delay. The transmission (TX) node in the protocol synchronizes with the reception (RX) node very before transmitting a packet, and it can adaptively estimate the synchronization error size according to the synchronization interval from minutes to hours. We conducted simulations and a testbed implementation to show the efficacy of the proposed protocol. We found that our protocol substantially outperforms other state-of-the-art protocols, resulting in order-of-magnitude increase in network lifetime over a variety of duty cycles.

A Synchronized Scheme Applying on Hybrid in On-Line Game (온라인 게임에서의 하이브리드기법을 적용한 동기화 기법)

  • Kime, Hye-Young
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.2
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    • pp.7-12
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    • 2011
  • Because development of high speed network, spread of internet, and high quality of computer performance, request and internet about massive multiplayer playing the game, is increasing. In order to experience realistic game play which is one of the most importance factor in massive multiplayer on-line, synchronization is importance matter. We propose synchronized and optimized scheme that combined FSM (Finite State Machine) and event holding method for efficient state synchronization for massive multiplayer on-line, and we show the effectiveness and reliability of our proposed scheme through the implementing and testing of the game server applying on our proposed scheme.

A Real-Time Synchronization Mechanism for Distributed Multimedia Applications (분산 멀티미디어 응용을 위한 실시간 동기화 메카니즘)

  • Park, Young-Sook;Lee, Syung-Won;Chung, Gi-Dong
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.12
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    • pp.3785-3793
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    • 2000
  • Effective synchronization specification model which can specify temrxlral relationship among media resolving asynchronous problem due to variable network delay is necessary in a distributed multimedia system. Therefore in this paper, we propose RTPN(Real- Time Petri Net) synchronization specification model based on Petri Net for multimedia application in a distributed real time environment. The proposed RTPN model supplies a tlexible decsription of the temporal relationship among various media objects by defining primary key media and relative key media according to delay and importance among media. Firing rule is instantly executed by firing function based on QoS values which supports intra-media and inter-media syncbronization. And asynchronous control algorithm for resynchronization of presentation level is possible more effective supporting of QoS.

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Study on the Dynamic Synchronizing Control of An Islanded Microgrid (독립운전 마이크로그리드의 능동형 동기 투입 제어에 관한 연구)

  • Cho, Chang-Hee;Jeon, Jin-Hong;Kim, Jong-Yul;Kwon, Soon-Man;Kim, Sung-Shin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.6
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    • pp.1112-1121
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    • 2011
  • A microgrid is an aggregation of multiple distributed generators (DGs) such as renewable energy sources, conventional generators, and energy storage systems that provide both electric power and thermal energy. Generally, a microgrid operates in parallel with the main grid. However, there are cases in which a microgrid operates in islanded mode, or in a disconnected state. Islanded microgrid can change its operational mode to grid-connected operation by reconnection to the grid, which is referred to as synchronization. Generally, a single machine simply synchronizes with the grid using a synchronizer. However, the synchronization of microgrid that operate with multiple DGs and loads cannot be controlled by a traditional synchronizer, but needs to control multiple generators and energy storage systems in a coordinated way. This is not a simple job, considering that a microgrid consists of various power electronics-based DGs as well as alternator-based generators that produce power together. This paper introduces the results of research examining an active synchronizing control system that consists of the network-based coordinated control of multiple DGs. Consequently, it provides the microgrid with a deterministic and reliable reconnection to the grid. The proposed method is verified by using the test cases with the experimental setup of a microgrid pilot plant.

Low Power MAC Protocol Design of an Efficient Preamble Exploiting Virtual Synchronization Scheme for Wireless Sensor Networks (무선 센서 네트워크를 위한 효율적인 프리앰블 가상 동기화 기법을 사용하는 저전력 MAC 프로토콜 설계)

  • Lee, Sung-Hun;Hwang, Se-Wook;Lee, Hyuk-Joon;Lee, Hyung-Geun
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.35 no.5B
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    • pp.762-770
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    • 2010
  • The researches about energy efficieny of wireless sensor MAC protocol is an issue in present days. Therefore, MAC and routing protocols for reducing energy consumption at sensor nodes is needed. In this study, a low-power MAC protocol for sensor network is proposed, which in based on X-MAC by exploiting virtual synchronization. The virtual synchronization technique lets senders postpone packet transmission until receivers' wake-up time, so that senders transmit only one or two short preambles. Using NS-2, a proposed MAC protocol improve the energy efficiency by 10% compared with the X-MAC protocol.

Implementation of Timing Synchronization in Vehicle Communication System

  • Lee, Sang-Yub;Lee, Chul-Dong;Kwak, Jae-Min
    • Journal of information and communication convergence engineering
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    • v.8 no.3
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    • pp.289-294
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    • 2010
  • In the vehicle communication system, transferred information is needed to be detected as possible as fast in order to inform car status located in front and rear side. Through the moving vehicle information, we can avoid the crash caused by sudden break of front one or acquire to real time traffic data to check the detour road. To be connecting the wireless communication between the vehicles, fast timing synchronization can be a key factor. Finding out the sync point fast is able to have more marginal time to compensate the distorted signals caused by channel variance. Thus, we introduce the combination method which helps find out the start of frame quickly. It is executed by auto-correlation and cross-correlation simultaneously using only short preambles. With taking the absolute value at the implemented synch block output, the proposed method shows much better system performance to us.

Performance Analysis of Frequency Synchronization for HDR-WPAN System (HDR-WPAN 시스템을 위한 주파수 동기 성능분석)

  • Park, Ji-Woo;Kang, Hee-Gok;Kim, Jae-Young;Oh, Chang-Heon
    • Journal of Advanced Navigation Technology
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    • v.8 no.2
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    • pp.163-168
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    • 2004
  • In this paper, we propose a frequency synchronization algorithm using characteristic of CAZAC sequence for HDR-WPAN and analyze the performance by signal constellation and EVM(error vector magnitude). The proposed frequency offset technique estimated each sample phase error of two sequences among 12 CAZAC sequences which have excellent autocorrelated characteristic. Estimated phase error is multiplied to each sample of next sequence for compensating the frequency offset. The remaining frequency offset after compensating it with two sequences has maximum 0.002 offsest ranges at each sample. The computer simulation proved that the permission of EVM value had satisfied in the case of DQPSK at 20[dB].

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Design of a 3GPP LTE system Information(MIB) detection simulator (3GPP LTE 시스템정보(MIB) 추출에 대한 연구)

  • Gwag, Gyoung-Hun;Oh, Hyuk-Jun
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2015.10a
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    • pp.827-829
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    • 2015
  • This paper presents process of the UE obtains the cell system information in order to achieve communication with the LTE network on the LTE. This paper deals with the process of extracting MIB(Master Information Block) cell system information in LTE. To study the 3GPP LTE standard spec series 36.200 and 36.300, the simulation is implemented to extract the MIB in MATLAB program. The simulation process is divided into three parts. It consisted of a part that extracts the PSS, SSS and MIB. Called a cell search process for detecting the PSS and SSS, the process is to be done in order to extract only the cell system information. The simulation program is verified based on the signal captured from the real Air.

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