• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.217-220
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• 2009

The two-way synchronization system in mobile environment processes synchronization of multi clients by order. In this case, that a synchronization operation, which takes long time to process, makes other clients wait is a problem. In this paper, treats to design and materialize a system which processes synchronization operations between clients without update conflicts as using multi queues. Also, compares performance between the simultaneous synchronization and the synchronization in consecutive order by the rate of process term of synchronization operation and the pattern of operation process.

• Journal of the Korea Society of Computer and Information
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• v.13 no.7
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• pp.213-220
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• 2008

In a distributed processing environment composed of many independent systems connected by networks, it is very important and difficult to make time synchronization between the systems. Especially in the USN environment the time synchronization is still more difficult than in general distributed processing environment because energy is limited and communication function is feeble. Even though of these difficulties, the USN environment requires higher precision of time synchronization. We of the typical applications requesting very strict time synchronization in USN is TDMA MAC. This paper proposes and evaluates a new time synchronization protocol HTSP(Hierarchical Time Synchronization Protocol) which is an advanced version of the FTSP(Flooding Time Synchronization Protocol) published recently. The time synchronization precision of the HTSP is equal to that of the FTSP, but the energy consumption of the HTSP is lower than that of the FTSP owing to the reduced number of broadcast messages. The simulation results show that the energy consumption of the HTSP is only 74% of that of the FTSP.

• Journal of Communications and Networks
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• v.18 no.1
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• pp.65-74
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• 2016

Ship ad-hoc network (SANET) extends the coverage of the maritime communication among ships with the reduced cost. To fulfill the growing demands of real-time services, the SANET requires an efficient clock time synchronization algorithm which has not been carefully investigated under the ad-hoc maritime environment. This is mainly because the conventional algorithms only suggest to decrease the beacon collision probability that diminishes the clock drift among the units. However, the SANET is a very large-scale network in terms of geographic scope, e.g., with 100 km coverage. The key factor to affect the synchronization performance is the signal propagation delay, which has not being carefully considered in the existing algorithms. Therefore, it requires a robust multi-hop synchronization algorithm to support the communication among hundreds of the ships under the maritime environment. The proposed algorithm has to face and overcome several challenges, i.e., physical clock, e.g., coordinated universal time (UTC)/global positioning system (GPS) unavailable due to the atrocious weather, network link stability, and large propagation delay in the SANET. In this paper, we propose a logical clock synchronization algorithm with multi-hop function for the SANET, namely multi-hop clock synchronization for SANET (MCSS). It works in an ad-hoc manner in case of no UTC/GPS being available, and the multi-hop function makes sure the link stability of the network. For the proposed MCSS, the synchronization time reference nodes (STRNs) are efficiently selected by considering the propagation delay, and the beacon collision can be decreased by the combination of adaptive timing synchronization procedure (ATSP) with the proposed STRN selection procedure. Based on the simulation results, we finalize the multi-hop frame structure of the SANET by considering the clock synchronization, where the physical layer parameters are contrived to meet the requirements of target applications.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.2
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• pp.91-97
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• 2014

Chaotic dynamics is an active research area in fields such as biology, physics, sociology, psychology, physiology, and engineering. Interest in chaos is also expanding to the social sciences, such as politics, economics, and societal events prediction. Most people pursue happiness, both spiritual and physical in many cases. However, happiness is not easy to define, because people differ in how they perceive it. Happiness can exist in mind and body. Therefore, we need to be happy in both simultaneously to achieve optimal happiness. To do this, we need to synchronize mind and body. In this paper, we propose a chaotic synchronization method in a mathematical model of happiness organized by a second-order ordinary differential equation with external force. This proposed mathematical happiness equation is similar to Duffing's equation, because it is derived from that equation. We introduce synchronization method from our mathematical happiness model by using the derived Duffing equation. To achieve chaotic synchronization between the human mind and body, we apply an idea of mind/body unity originating in Oriental philosophy. Of many chaotic synchronization methods, we use only coupled synchronization, because this method is closest to representing mind/body unity. Typically, coupled synchronization can be applied only to non-autonomous systems, such as a modified Duffing system. We represent the result of synchronization using a differential time series mind/body model.

• ETRI Journal
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• v.30 no.1
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• pp.59-67
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• 2008

The necessity for the precise time synchronization of measurement data from multiple sensors is widely recognized in the field of global positioning system/inertial navigation system (GPS/INS) integration. Having precise time synchronization is critical for achieving high data fusion performance. The limitations and advantages of various time synchronization scenarios and existing solutions are investigated in this paper. A criterion for evaluating synchronization accuracy requirements is derived on the basis of a comparison of the Kalman filter innovation series and the platform dynamics. An innovative time synchronization solution using a counter and two latching registers is proposed. The proposed solution has been implemented with off-the-shelf components and tested. The resolution and accuracy analysis shows that the proposed solution can achieve a time synchronization accuracy of 0.1 ms if INS can provide a hard-wired timing signal. A synchronization accuracy of 2 ms was achieved when the test system was used to synchronize a low-grade micro-electromechanical inertial measurement unit (IMU), which has only an RS-232 data output interface.

• Journal of the Korea Computer Industry Society
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• v.4 no.10
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• pp.695-702
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• 2003

It is necessary for us to have proper synchronization technology in order for continuous media and non-continuous media to be integrated and presented. In case of continuous media, it would be possible to convey significant information only after relevant synchronization is completed in the continuous media itself. In this thesis, I mentioned integration of these multi-media, basic notion of synchronization and synchronization technology. In order to process synchronization, I have researched into information used to fractionize methods regarding synchronization. And I have also discussed synchronization problems found in integration of continuous multi-media and through researching into case study of MHEG, I have analyzed how the synchronization of multi-media is processed and applied.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.13 no.11
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• pp.5446-5463
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• 2019

Parallel computing system components should be harmonized, and this harmonization is kept existent using synchronization time. Synchronization time affects the system in two ways. First, if we have too little synchronization time, some tasks face the problem of harmonization, as they need appropriate time to update and synchronize with the system. Second, if we allocate a large amount of time, stall system created. Random allocation of synchronization time for parallel systems slows down not only the booting time of the system but also the execution time of each application involved in the system. This paper presents a simulator used to test and allocate appropriate synchronization time for distributed and parallel heterogeneous systems. The simulator creates the parallel and heterogeneous system to be evaluated, and lets the user vary the synchronization time to optimize the booting time. NS3-cGEM5 simulator in this paper is formed by HLA-RTI federation integration of the two independent architecture and network simulators - NS3 and cGEM5. Therefore, nodes created on these simulators need synchronizations for harmonized system performance. We tested and allocated the appropriate synchronization time for our sample parallel system composed of one x86 server and three ARM clients.

• Journal of the Korean Institute of Intelligent Systems
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• v.16 no.1
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• pp.18-23
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• 2006

The complex system synchronization methods improve based on synchronization theory; however, due to deeper level of complexity within complex system compared to that of chaos system, it is difficult to synchronize complex signals from complex system. In this paper, we proposed coupled-synchronization theory in the n-double scroll circuit and new embedding driven-synchronization theory, a method of accomplishing synchronization with only one parameter out of may parameters, in hyper-chaos circuit to apply synchronization in the complex system. By applying proposed synchronization method using computer simulation, we confirmed the accomplishment of superior synchronization in complex system.

• Journal of Korea Multimedia Society
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• v.8 no.2
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• pp.279-286
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• 2005

As the mobile environment has been generalized, data synchronization with mobile devices or mobile device and PC/server is required. To deal with the problem, the consortium was established by the companies, such as Motorola, Ericsson, and Nokia, and released SyncML(Synchronization Markup Language) as a standard of industrial area for interoperating with data synchronization and various transmission protocol. But, in synchronization process, when more than two clients requested data synchronization, data conflict can be happened. This paper studies the various conflict reasons that can happen in data synchronization processes and groups them systematically Through the analyzed information, we compose the Change Log Information(CLI) that can keep track of the chased information about synchronization. And we suggest an operation policy using CLI. Finally, we design an algorithm and adapt the policy as a method for the safety and consistency of data.

• Journal of Korea Multimedia Society
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• v.8 no.9
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• pp.1153-1162
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• 2005

In this paper, we developed an XML Document Data Synchronization System for java(XDS4j) based on both SyncML(Synchronization Markup Language) framework Sync4j and embedded database system Berkeley DB XML. Because most existing data synchronization systems are based on file systems, data synchronization times at Fast Sync in those systems are very delayed. In the XDS4j, however, XML documents data produced at SyncML client and SyncML server are managed by embedded database system, and also synchronization time at Fast Sync is reduced because only partial elements are accessed by applying to XPath.