• Journal of Korea Multimedia Society
• /
• v.8 no.3
• /
• pp.389-397
• /
• 2005

In this paper, we study the synchronization method of animated simulations and VRs for on-line virtual reality education system. To build the data of animated simulations and synchronization modules of VRML content, the media-synchronizing technology, HTML + TIME and scripts are used. The VRML control module ismade into Java applet using the Java EAI provided for the web and the interface for VRML contents. To control the animation of VRML contents, the node information is extracted, and an animation production template capable of controlling animation in inter-connection with VRML content is made. With evaluation of the animation control performance, processing speed, synchronization performance between media in the system built, more improved results are obtained. We would like to suggest a education system with easy system construction and various multi-medium applicability by realizing HTML + TIME media synchronization and VRML web 3D virtual reality creation techniques, and animated images and 3D animation controls according to time using Java through this study.

• Journal of Korea Society of Industrial Information Systems
• /
• v.15 no.5
• /
• pp.137-148
• /
• 2010

In this paper, a mobile office support. system which consists of mobile devices and servers is proposed. An efficient mobile office support system is required to study since the existing mobile office support systems may face the serious problems such as an absence of interoperability, difficulties of data synchronization and device management in the near future, especially when a company has a large number of outdoor service employees. In this paper, a mobile office support system requirements for a company with a large number of outdoor service employees is proposed. And then, the methods to satisfy the requirements using a remote data synchronization and a remote device management technologies are proposed. The mobile office support system proposed in this paper synchronizes remotely a large number of various mobile devices of employees with centralized servers located in the company. In addition, it manages the mobile devices remotely for the employees. This paper proposes a mobile office support system based on OMA(Open Mobile Alliance) DS(Data Synchronization) and DM(Device Management) protocols. As OMA DS and DM protocols are de facto international standards, the interoperability between the mobile office support systems can be guaranteed.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.12 no.2
• /
• pp.974-987
• /
• 2018

This paper presents a novel and efficient data transmission scheme based on mobile edge computing for the massive IoT environments which should support various type of services and devices. Based on an accurate and precise synchronization process, it maximizes data transmission throughput, and consistently maintains a flow's latency. To this end, the proposed efficient software defined data transmission scheme (ESD-DTS) configures and utilizes synchronization zones in accordance with the 4 usage cases, which are end node-to-end node (EN-EN), end node-to-cloud network (EN-CN), end node-to-Internet node (EN-IN), and edge node-to-core node (EdN-CN); and it transmit the data by the required service attributes, which are divided into 3 groups (low-end group, medium-end group, and high-end group). In addition, the ESD-DTS provides a specific data transmission method, which is operated by a buffer threshold value, for the low-end group, and it effectively accommodates massive IT devices. By doing this, the proposed scheme not only supports a high, medium, and low quality of service, but also is complied with various 5G usage scenarios. The essential difference between the previous and the proposed scheme is that the existing schemes are used to handle each packet only to provide high quality and bandwidth, whereas the proposed scheme introduces synchronization zones for various type of services to manage the efficiency of each service flow. Performance evaluations show that the proposed scheme outperforms the previous schemes in terms of throughput, control message overhead, and latency. Therefore, the proposed ESD-DTS is very suitable for upcoming 5G networks in a variety of massive IoT environments with supporting mobile edge computing (MEC).

• Journal of KIISE:Computing Practices and Letters
• /
• v.8 no.6
• /
• pp.647-656
• /
• 2002

Synchronization is the process of making replicated data on multiple devices be consistent, i.e., identical with each other. In Dec. 2000, major handheld computer manufacturers including Nokia, Ericsson, IBM published the SyncML protocol specification. In this paper, we describe the CNU SyncML server for PIMS(Personal Information Management System) service that we developed based on the SyncML specification. The server architecture and capabilities of the frames are presented along with the procedure of message processing by each frame. We put the CNU SyncML server to the conformance tests and interoperability tests to confirm its functionality. The session managing mechanism of the CNU SyncML server showed better performance than our previous implementations.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.1
• /
• pp.141-146
• /
• 2011

The GIS service has to provide latest spatio-temporal data for the effective service. The two-way synchronization scheme collects updated spatio-temporal data in the field and synchronizes with a server by using the wireless network. However, since the two-way synchronization scheme processes sequentially synchronizing work of clients, it has the problem that the synchronization of multiple clients takes long time. In this paper, we propose the concurrent synchronizations scheme based on the multi-queue in order to reduce the waiting time of multiple clients. We also build both schemes and evaulate the performance test. The results show that the proposed scheme reduce the waiting time by 31%.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.32 no.3A
• /
• pp.237-246
• /
• 2007

Clock Synchronization is one of the most basic factors to be considered when we implement an indoor synchronization network for indoor positioning. In this paper, we present a new synchronization algorithm which does not employ time stamps in order to reduce the hardware complexity and data overhead. In addition to that, we describe an algorithm that is designed to compensate the frequency drift giving an serious impact on the synchronization performance. The performance evaluation of the proposed algorithm is achieved by investigating MTIE (Maximum Time Interval Error) values through simulations. In the simulations, the frequency drift values of the practical oscillators are used. From the simulation results, it is investigated that we can achieve the synchronization performance under 10 ns when we use 1 second synchronization interval with 1 ns resolution and TCXOs (Tmperature Compensated Cristal Oscillators) both in the master clock and the slave clock.

• Journal of Advanced Navigation Technology
• /
• v.26 no.6
• /
• pp.441-447
• /
• 2022

In this paper, we propose a FLL-assisted-PLL based time synchronization algorithm for telemetry systems where frequency and phase errors exist in time synchronization pulse. The telemetry system may analyze the flight state by acquiring the state information in the distributed system. Therefor, in order to collect each state information without errors, precise time synchronization between the master and the slave is required. At this time, the master's time pulse have frequency and phase changes that can be caused by external and internal factors, so a method to maintain precision time synchronization is essential to provide telemetry data continuously. We propose the FLL-assisted-PLL based algorithm that is capable of high-speed synchronization and has high time synchronization accuracy. The proposed algorithm is verified through python simulation, and the VHDL Logic has been implemented in FPGA to check the performance according to the frequency errors and phase errors.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.13 no.11
• /
• pp.5512-5517
• /
• 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.

• Journal of the Korea Institute of Information Security & Cryptology
• /
• v.26 no.4
• /
• pp.929-940
• /
• 2016

The IMO e-navigation strategy has requested a communication infrastructure providing authorized seamless information transfer between stakeholders. The Maritime Cloud is the term used to describe the concept of an infrastructure that support authorized, seamless information transfer, adding those elements, that are necessary to support the e-navigation domain. It is necessary to consider the study on maritime cloud security, but the study is still an early stage. In this paper, we propose a secure synchronization method for the maritime cloud services. The proposed method can be synchronize between the vessel based on the SH-Tree, and it has the advantage that there is no exposure information in the synchronization process.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.5 no.1
• /
• pp.111-115
• /
• 2011

In this paper, we present a novel time-synchronization method for distributed systems to measure the body motion. The distributed system scheme is considered because human data acquisition systems tend to have a centralized controller with sensors connected with a long range of electric wires running through the subject's body, which results in inconvenience. Utilizing simple key switches and digital input ports for reading the key, the proposed method requires a very simple hardware structure, which means less power consumption compared with the well-known ubiquitous sensor network. After measuring the motion data as well as the synchronization pulses, the proposed method compensates, in offline, the difference of the sampling instance between the two systems by scaling the time difference. The paper presents experimental results to show the validity of the proposed method.