• Title/Summary/Keyword: Real-time Synchronization Service

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Forensic Investigation Procedure for Real-time Synchronization Service (실시간 동기화 서비스에 대한 포렌식 조사 절차에 관한 연구)

  • Lee, Jeehee;Jung, Hyunji;Lee, Sangjin
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.22 no.6
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    • pp.1363-1374
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    • 2012
  • The number and use of Internet connected devices has dramatically increased in the last several years. Therefore many services synchronizing data in real-time is increasing such as mail, calendar and storage service. This service provides convenience to users. However, after devices are seized, the data could be changed because of characteristic about real-time synchronization. Therefore digital investigation could be difficult by this service. This work investigates the traces on each local device and proposes a method for the preservation of real-time synchronized data. Based on these, we propose the procedures of real-time synchronization data.

qPALS: Quality-Aware Synchrony Protocol for Distributed Real-Time Systems

  • Kang, Woochul;Sha, Lui
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.10
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    • pp.3361-3377
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    • 2014
  • Synchronous computing models provided by real-time synchrony protocols, such as TTA [1] and PALS [2], greatly simplify the design, implementation, and verification of real-time distributed systems. However, their application to real systems has been limited since their assumptions on underlying systems are hard to satisfy. In particular, most previous real-time synchrony protocols hypothesize the existence of underlying fault tolerant real-time networks. This, however, might not be true in most soft real-time applications. In this paper, we propose a practical approach to a synchrony protocol, called Quality-Aware PALS (qPALS), which provides the benefits of a synchronous computing model in environments where no fault-tolerant real-time network is available. qPALS supports two flexible global synchronization protocols: one tailored for the performance and the other for the correctness of synchronization. Hence, applications can make a negotiation flexibly between performance and correctness. In qPALS, the Quality-of-Service (QoS) on synchronization and consistency is specified in a probabilistic manner, and the specified QoS is supported under dynamic and unpredictable network environments via a control-theoretic approach. Our simulation results show that qPALS supports highly reliable synchronization for critical events while still supporting the efficiency and performance even when the underlying network is not stable.

Real-time Synchronization Algorithm for Industrial Hybrid Networks: CAN and Sensor Networks (공장 자동화용 혼합형 네트워크를 위한 실시간 동기화 알고리즘의 성능 분석: CAN과 센서 네트워크)

  • Jung, Ji-Won;Kim, Dong-Sung
    • Journal of Institute of Control, Robotics and Systems
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    • v.16 no.2
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    • pp.194-201
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    • 2010
  • This paper discuss a performance evaluation of the synchronization algorithm for hybrid networks in industrial environments. The proposed algorithms minimizes synchronization errors which were caused from channel, Propagation, and frequency delays. The modified RBS and offset synchronization methods can be operated by adjustment parameters. The differential BP (Back-off Period) adjustment can synchronize the local time of each node with master node's time in hybrid networks. For the performance analysis, the data transmission time between the wired and wireless devices are investigated. The experimental results show the performance evaluations in terms of the polling service time and an average end-to-end delay.

Adaptive Multimedia Synchronization Using Waiting Time (대기시간을 이용한 적응형 멀티미디어 동기화 기법)

  • Lee, Gi-Seong;Lee, Geun-Wang;Lee, Jong-Chan;O, Hae-Seok
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.2S
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    • pp.649-655
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    • 2000
  • Real-time application programs have constraints which need to be met between media-data. These constraints represents the delay time ad quality of service between media-data to be presented. In order to efficiently describe the delay time and quality of service, a new synchronization mechanism is needed. Proposed paper is a dynamic synchronization that minimized the effects of adaptive transmission delay time. That is, the method meets the requirements of synchronization between media-dat by handling dynamically the adaptive waiting time resulted from variations of delay time. In addition, the mechanism has interval adjustment using maximum delay jitter time. This paper decreases the data loss resulted from variation of delay time and from loss time of media-data by means of applying delay jitter in order to deal with synchronization interval adjustment. Plus, the mechanism adaptively manages the waiting time of smoothing buffer, which leads to minimize the gap from the variation of delay time. The proposed paper is suitable to the system which requires the guarantee of high quality of service and mechanism improves quality of services such as decrease of loss rate, increase of playout rate.

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Mechanism of Multimedia Synchronization using Delay Jitter Time (지연지터시간을 이용한 멀티미디어 동기화 기법)

  • Lee, Keun-Wang;Jun, Ho-Ik
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.11
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    • pp.5512-5517
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    • 2012
  • In this paper we suggest multimedia synchronization model that is based on the Petri-net and services desirable quality of service requirement. Proposed model applies variable buffer which can be allowed, and then it presents high quality of service and real time characteristics. This paper decreases the data loss resulted from variation of delay time and from loss time of media-data by means of applying delay jitter in order to deal with synchronization interval adjustment. Plus, the mechanism adaptively manages the waiting time of smoothing buffer, which leads to minimize the gap from the variation of delay time. The proposed paper is suitable to the system which requires the guarantee of high quality of service and mechanism improves quality of services such as decrease of loss rate, increase of playout rate.

Petri-net Based Multimedia Synchronization Model for High Quality of Service (고품질의 서비스를 위한 페트리네트 기반의 멀티미디어 동기화 모델)

  • 이근왕;이기성;이문호;오해석;김은영
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.24 no.6B
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    • pp.997-1003
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    • 1999
  • It is required that synchronization model can describe various multimedia objects flexibly in the view point of time relationship and also respond quality of service requirement about jitter which is time difference between intramedia and skew which is time difference between intermedia. es desirable quality of service requirement. Proposed model applies maximum jitter and skew values which can be allowed, and then it presents high quality of service and real applies maximum jitter and skew values which can be allowed, and then it presents high quality of service and real time characteristics. In this paper we expend Petri-net and propose new synchronization specification model and apply two analysis method of Petri-net to prove oIn this paper we suggest multimedia synchronization model that is based on the Petri-net and servicur model suggested. We compared with other models and showed high QoS.

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A Framework and Synchronization Mechanism for Real-time Multimedia Streaming Services based on the Time-triggered Message-triggered Object (실시간 멀티미디어 스트리밍 서비스를 위한 Time-triggered Message-triggered Object 기반의 프레임워크 및 동기화 메커니즘)

  • Jo, Eun-Hwan;Kim, Moon-Hae
    • The KIPS Transactions:PartC
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    • v.13C no.6 s.109
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    • pp.669-676
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    • 2006
  • In this paper, we present a new framework and stream synchronization mechanism to effectively support developing real-time multimedia streaming services by using a real-time object model named TMO (Time-triggered Message-triggered Object). The purpose of the framework is twofold. Firstly, the framework helps developers to design complex distributed real-time multimedia streaming services. Secondly, it supports timely streaming facilities. In order to achieve these goals, our framework is consist of Multimedia Streaming TMO, MMStreaming TMO Support Library and TMO Support Middleware. The time-triggered spontaneous feature of the MMStream TMO and a global-time based synchronization scheme is used as a regulator against the irregular deliveries and processing of media units caused by QoS non-guaranteed systems and communication channels. In conclusion, timely service capability of our framework is expected to contributed to overall enhancement of the real-time multimedia streaming.

Design and Verification of Multimedia Synchronization Model using PetriNet (페트리 네트를 이용한 멀티미디어 동기화 모델의 설계 및 검증)

  • Oh, Myoung-Kwan;Lee, Keun-Wang
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.2
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    • pp.584-589
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    • 2010
  • In this paper we suggest multimedia synchronization model that is based on the Petri-net and services desirable quality of service requirement. Proposed model applies variable buffer which can be allowed, and then it presents high quality of service and real time characteristics. In this paper we expend Petri-net and propose new multimedia synchronization specification model in PBMSM and apply two analysis method of Petri-net to prove our model suggested. We compared with other models and showed high QoS.