• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.1
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• pp.91-96
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• 2012

Recently, the research of security and its related problems has been received great interested. The research for hper-chaos systems and its synchronization are actively processing as one of method to apply to secure and cryptography communication. In this paper, we propose the synchronization method by coupling coefficient of linear and nonlinear in order to accomplish the synchronization of hyper-chaos system that organized by SC-CNN(State-Controlled Cellular Neural Network). We also verify and confirm the result of synchronization between entire transmitter and receiver, and each subsystem in transmitter and receiver through the phase portrait and difference of time-series by the computer simulation.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.102-108
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• 2015

In general, two way satellite communication systems based on TDMA(Time Division Multiple Access) require network clock synchronization between hub station and remote terminals. This paper describes basic concepts for network clock synchronization based on NCR(Network Clock Reference) clock recovery scheme as suggested in DVB-S2/ RCS2 international standards. in addition, a new NCR insertion method has been proposed and evaluated in terms of supporting CCM mode as well as ACM mode which optimizes throughput by changing code rates and modulation types ranging from QPSK to 32-APSK.

• Proceedings of the IEEK Conference
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• 2003.07d
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• pp.1697-1700
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• 2003

The multi-user online game is a typical example of networked graphic applications. Increasing the reality of such a game requires the minimization of problems due to the network delay. In this paper, we propose a game architecture that reduces the network delay needed for message transfer, and a method for synchronization of game states in clients . The proposed game architecture is region proxy-based, and it can require a less network delay than a conventional client-server style that is usually used in commercial games. In our synchronization method, messages are processed in a batch-mode style and the number of rollbacks needed for synchronization significantly decreases. Our experiment shows that our method provides better performance than previous TSS (Trailing State Synchronization).

• Journal of Korea Society of Industrial Information Systems
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• v.5 no.1
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• pp.16-24
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• 2000

In the distributed multimedia document system, media objects distributed over a computer network are retrieved from their sources and presented to users according to specifed temporal relations. For effective presentation, synchronization have to he supported. Furthermore, presentation in distributed environments is influenced by network band with and delay, so they have to be considered for synchronization. This paper propose a distributed multimedia presentation model that supports synchronization effectively. In this model, when media objects are transfered from servers to a client, network situation and resources are monitored and thus a feedback message for change of them is sent to sever. Then, the sever adjusts the data sending rate to control synchronization.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.42 no.1
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• pp.61-66
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• 2005

Location Positioning is a major technology for ubiquitous computing. Recently the research on Location Positioning using UWB is on going. In order to construct an in-door location network, synchronization of base stations is very important. NTP is Popularly used as clock synchronization protocol ranging from LAN to WAN. Also Master-Slave scheme is the simplest method to synchronize in-door network. We compare and analyze NTP and Master-Slave schemes according to the statistical channel model for indoor multipath propagation environment. In this paper, error ranges are calculated at various circumstances that in-door network expands from one primary base station into several base stations. We compared the correctness of NTP and Master-Slave synchronization methods. NTP is more reasonable synchronization protocol in in-door environment.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.39-47
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• 2015

In this paper, we propose a new time synchronization algorithm using CoAP(constrained-application protocol) in sensor network environment, which handles a technique that synchronizes an explicit timestamp between sensor nodes not including an additional module for time-setting and sensor node gateway linked to internet time server. CoAP is a standard protocol for sensor data communication among sensor nodes and sensor node gateway to be built much less memory and power supply in constrained network surroundings including serious network jitter, packet losses, etc. We have supplied an exact time synchronization implementation among small and cheap IP-based sensor nodes or non-IP based sensor nodes and sensor node gateway in sensor network using CoAP message header's option extension. On behalf of conventional network time synchronization method, as our approach uses an exclusive protocol 'CoAP' in sensor network, it is not to become an additional burden for synchronization service to sensor nodes or sensor node gateway. This method has an average error about 2ms comparing to NTP service and offers a low-cost and robust network time synchronization algorithm.

• Proceedings of the KIEE Conference
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• 1987.07b
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• pp.903-906
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• 1987

The digital private line network provides synchronous data communications over dedicated facilities at several speeds. This service became available to several major metropolitan areas in 1986 with speeds of 4800, 9600, 56000 b/s. The network is expected to grow to include many city areas. In this paper, synchronization plan for the network is proposed.

• ETRI Journal
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• v.26 no.4
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• pp.360-366
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• 2004

Synchronization Markup Language (SyncML) is a specification of a common data synchronization framework for synchronizing data on networked devices. SyncML is designed for use between mobile devices that are intermittently connected to a network and network services that are continuously available on the network. We have designed and developed a data synchronization system based on the SyncML protocol and evaluated the throughput of the system using the stochastic Petri nets package (SPNP) and analyzed the relationship between the arrival rate and the system resources. Using this model, we evaluate various performance measures in different situations, and we estimate the relationship between the arrival rate and the system resources. From the results, we can estimate the optimal amount of resources due to the arrival rate before deploying the developed system.

• Proceedings of the IEEK Conference
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• 2002.07b
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• pp.794-797
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• 2002

We consider a master-slave pulse-coupled network of bifurcating integrate-and-fire circuits. The network exhibits in-phase chaotic synchronization and various periodic synchronization phenomena. In order to analyze these phenomena precisely, we derive a one-dimensional return map. Also using a simple test circuit, typical phenomena are demonstrated in the laboratory.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.11
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• pp.1144-1149
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• 2009

This paper deals with the time synchronization problem over SpaceWire links. SpaceWire is a standard for high-speed links and networks between spacecraft components, which was invented for better, cheaper, faster on-board data handling in spacecraft. The standard defines Time-Code for time distribution over SpaceWire network. When a Time-Code is transmitted, transmission delay and jitter is unavoidable. In this paper, a mechanism to remove Time-Code transmission delay and jitter over SpaceWire links is proposed and implemented with FPGA for validation. The proposed mechanism achieves high resolution clock synchronization over SpaceWire links, complies with the standard and can be easily adopted over SpaceWire network.