• Title, Summary, Keyword: synchronization

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Effective Elimination Method of Redundant Synchronization Instructions in MIMD Systems (MIMD 시스템에서의 효율적인 중복 동기화명령어 제거 기법)

  • 김병수;황종선;박두순
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.29B no.10
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    • pp.1-9
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    • 1992
  • This paper presents an effective synchronization algorithm. It is different from the existing synchronization methods by inserting appropriate synchronization instructions between statements according to different kinds of data dependencies. The overhead caused by too many synchronization instructions in a loop can be a critical problem. Synchronization optimization is a method which discriminates and eliminates the redundant synchronization instructions in a loop. In this paper, a new synchronization optimization algorithm is developed, and performance analysis using simulation on the UNIX operating system is carried out.

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Multimedia Synchronization Scenario Method for Synchronization Anomaly (동기이상을 위한 멀티미디어 동기시나리오방법)

  • 전병호;김태균
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.31A no.9
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    • pp.44-52
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    • 1994
  • When a constructed multimedia application system transfers a various media of which quality of service is different, a previously constituted synchronization at source site generates the synchronization anomaly that the synchronization relation is broken by a delay or a data loss at destination. To solve the synchronization anomaly, we propose the “Multimedia synchronization scenario method : MSSM” which defines as one(1) event all objects generated at multimedia application and creates the optimal scenario of multimedia presentation under temporal constraints. The characteristics of MSSM can minimize the delay effect, guarantee the media stream continuity for preventing the media stretch, and provide the synchronization information to a user and/or a system. After deciding a synchronization possibility. MSSM confirm user its information. If there is a synchronization possibility. MSSM products optimal multimedia presentation scenario, and can present multimedia adaptively.

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Performance Evaluation of Synchronization Method for Reducing the Overall Synchronization Time in Digital Radio Mondiale Receivers

  • Kwon, Ki-Won;Kim, Seong-Jun;Hwang, Jun;Paik, Jong-Ho
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.7 no.8
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    • pp.1860-1875
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    • 2013
  • In this paper, we present a comparative performance evaluation of the sampling frequency synchronization method that eliminates the initial sampling frequency offset (SFO) to reduce the overall synchronization time in Digital Radio Mondiale (DRM) receivers. To satisfy the advanced synchronization performance requirements of DRM receivers, we introduce the conventional DRM synchronization method (Method 1) and another method (Method 2), which does not perform the initial sampling frequency synchronization in the conventional synchronization method (both methods are mentioned later in this paper). To demonstrate the effectiveness of the performance evaluation, analytical expressions for frame detection are derived and simulations are provided. Based on the simulations and numerical analysis, our result shows that Method 2, with a negligible performance loss, is robust to the effects of the initial sampling frequency synchronization even if SFO is present in the DRM signal. In addition, we verify that the inter-cell differential correlation used between reference cells is robust to the effect of the initial SFO.

Multimedia Conferencing System with Intramedia and Intermedia Synchronization Support

  • Yoo, Sang-Shin;Kim, Duck-Jin
    • Journal of Electrical Engineering and information Science
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    • v.2 no.3
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    • pp.41-50
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    • 1997
  • In this paper, we describe the design, implementation and evaluation for a multimedia conferencing system with intramedia and intermedia synchronization support between audio and video. The synchronization mechanism proposed here is capable of dynamically adapting to various network conditions thus providing an optimized QoS. In realizing the system based on this mechanism, NeVoT on Mbone is used for audio and VIC for video. Furthermore a synchromization controller is designed and realized with a unique process in supporting intermedia synchronization. Each media agents handling its media stream are modified with intramedia synchronization function. And a communicative function between media agents and synchronization controller is added as well for intermedia synchronization function. Each media agents function reports its buffering status to the synchronization control process which in turn send out optimized buffering delay value thus supporting intermedia synchronization. The realized system is configured and tested on Ethernet and ATM network where performance measurements were performed and its effective synchronization support has been assured.

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A Study on the Impact of IT and SCM Process Management Capability on e-SCM Performance (IT와 SCM 프로세스 관리역량이 e-SCM 성과에 미치는 영향에 관한 연구)

  • Lee, Sun-Ro;Kim, Ki-Young
    • Asia pacific journal of information systems
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    • v.17 no.3
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    • pp.79-103
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    • 2007
  • The main purpose of this study is to define antecedents that influence e-SCM synchronization and to investigate how it affects e-SCM performance. We, therefore, investigate (1) the impact of firms' internal IT planning capabilities on e-SCM synchronization and on SCM process management capability, (2) the impact of firms' internal IT infrastructure on e-SCM synchronization and on SCM process management capability, (3) the impact of firms' internal SCM process management capabilities on e-SCM synchronization, and finally (4) the impact of e-SCM synchronization on SCM performance. A survey has been administrated to the firms' SCM and marketing staffs and 171 returns analyzed. The results show that (1) IT plan has not direct impacts on e-SCM synchronization, but has direct impacts on organizational support, purchasing, and operations processes except logistics process. IT plan, however, has indirect impacts on e-SCM synchronization through purchasing and operations of SCM process management capability. (2) IT infrastructure has both direct and indirect effects on e-SCM synchronization, and also has direct impacts on organizational support, purchasing, and operations processes except logistics process. (3) SCM process management capabilities have direct impacts on e-SCM synchronization. Among these SCM core processes purchasing positively influences operations, which in turn positively influences logistics process management capability. (4) e-SCM synchronization has positive impacts on SCM performance indicator (SCOR), such as delivery reliability, responsiveness & flexibility, and cost. These results indicate that e-SCM synchronization can be critical to achieve better internal performance like cost and external performance like delivery reliability, responsiveness & flexibility of firms' SCM. In sum, this study demonstrates that the intervening role of e-SCM synchronization between e-SCM performance and IT management capability and between e-SCM performance and SCM core process management capability has been significant in achieving better e-SCM performance. Therefore, it can be suggested that e-SCM performance should be accomplished in consequence of the acceleration of e-SCM synchronization through the enhancement of preceding factors for the e-SCM synchronization.

An Efficient symbol Synchronization Scheme with an Interpolator for Receiving in OFDM (OFDM 방식의 수신기를 위한 보간기의 효율적인 심볼 동기방법의 성능분석)

  • 김동옥;윤종호
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.574-577
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    • 2002
  • In this paper, we propose a new symbol time synchronization scheme suitable for the OFDM system with an interpolator. The proposed performs the following three steps. In the first step, the coarse symbol time synchronization is achieved by continuously measuring the average power of the received envelope signal. Based on this average power, the detection possibility for the symbol time synchronization is determined. If the signal is sufficient for synchronization, we next perform a relatively accurate symbol time synchronization by measuring the correlation a short training signal and the received envelope signal. Finally, an additional frequency synchronization is performed with a long training signal to correct symbol synchronization errors caused by the phase rotation. From the simulation results, one can see that the proposed synchronization scheme provides a good synchronization performance over frequency selective channels.

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Low Latency Synchronization Scheme Using Prediction and Avoidance of Synchronization Failure in Heterochronous Clock Domains

  • Song, Sung-Gun;Park, Seong-Mo;Lee, Jeong-Gun;Oh, Myeong-Hoon
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.15 no.2
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    • pp.208-222
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    • 2015
  • For the performance-efficient integration of IPs on an SoC utilizing heterochronous multi-clock domains, we propose a synchronization scheme that causes low latency overhead when data are crossing clock boundaries. The proposed synchronization scheme is composed of a clock predictor and a synchronizer. The clock predictor of a sender clock domain produces a predicted clock that is used in a receiver clock domain to detect possible synchronization failures in advance. When the possible synchronization failures are detected, a synchronizer at the receiver delays data-capture times to avoid the possible synchronization failures. From the simulation of the proposed scheme through SPICE modeling using a Chartered $0.18{\mu}m$ CMOS process, we verified the functionalities and timing behavior of the clock predictor and the synchronizer. The simulation results show that the clock predictor produces a predicted clock before a synchronization failure, and the synchronizer samples data correctly using the predicted clock.

Software-based Performance Analysis of a Pseudolite Time Synchronization Method Depending on the Clock Source

  • Lee, Ju Hyun;Hwang, Soyoung;Yu, Dong-Hui;Park, Chansik;Lee, Sang Jeong
    • Journal of Positioning, Navigation, and Timing
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    • v.3 no.4
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    • pp.163-170
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    • 2014
  • A pseudolite is used as a GPS backup system, and is also used for the purpose of indoor navigation and correction information transmission. It is installed on the ground, and transmits signals that are similar to those of a GPS satellite. In addition, in recent years, studies on the improvement of positioning accuracy using the pseudorange measurement of a pseudolite have been performed. As for the effect of the time synchronization error between a pseudolite and a GPS satellite, a time synchronization error of 1 us generally induces a pseudorange error of 300 m; and to achieve meter-level positioning, ns-level time synchronization between a pseudolite and a GPS satellite is required. Therefore, for the operation of a pseudolite, a time synchronization algorithm between a GPS satellite and a pseudolite is essential. In this study, for the time synchronization of a pseudolite, "a pseudolite time synchronization method using the time source of UTC (KRIS)" and "a time synchronization method using a GPS timing receiver" were introduced; and the time synchronization performance depending on the pseudolite time source and reference time source was evaluated by designing a software-based pseudolite time synchronization performance evaluation simulation platform.

Low Power Time Synchronization for Wireless Sensor Networks Using Density-Driven Scheduling

  • Lim, HoChul;Kim, HyungWon
    • Journal of information and communication convergence engineering
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    • v.16 no.2
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    • pp.84-92
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    • 2018
  • For large wireless sensor networks running on battery power, the time synchronization of all sensor nodes is becoming a crucial task for waking up sensor nodes with exact timing and controlling transmission and reception timing. However, as network size increases, this synchronization process tends to require long processing time consume significant power. Furthermore, a naïve synchronization scheduler may leave some nodes unsynchronized. This paper proposes a power-efficient scheduling algorithm for time synchronization utilizing the notion of density, which is defined by the number of neighboring nodes within wireless range. The proposed scheduling algorithm elects a sequence of minimal reference nodes that can complete the synchronization with the smallest possible number of hops and lowest possible power consumption. Additionally, it ensures coverage of all sensor nodes utilizing a two-pass synchronization scheduling process. We implemented the proposed synchronization algorithm in a network simulator. Extensive simulation results demonstrate that the proposed algorithm can reduce the power consumption required for the periodic synchronization process by up to 40% for large sensor networks compared to a simplistic multi-hop synchronization method.

A New Synchronization Scheme for Parallel Processing of Loop with Constant and Variable Dependence Distance (불변 및 가변 종속거리를 갖는 루프의 병렬처리를 위한 새로운 동기화 기법)

  • 이광형;황종선;박두순
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.5
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    • pp.693-701
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    • 1995
  • In most application programs, loops usually comprise most of the computation in a program and are the most important source of parallelism. When loops are executed on multiprocessors, the cross iteration data dependences need to be enforced by synchronization between processors. Existing synchronization schemes have been studied mainly on the loop with constant dependence distance. When these schemes are applied to the loop with variable dependence distance, there exists lots of overhead by the use of unnecessary synchronization variables and execution of unuseful synchronization instructions. Even though there exist various variable synchronization schemes, they have a lot of run-time overhead to compute synchronization information. In this paper, we present a new synchronization scheme, Synch-Free/Synch-Hold for managing synchronization efficiently on the loop with constant and variable dependence distance.

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