• Journal of the Institute of Electronics Engineers of Korea CI
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• v.39 no.6
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• pp.53-67
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• 2002

The multimedia synchronization is one of the key issues to be resolved in order to provide a good quality of multimedia related services, such as Video on Demands(VoD), Lecture on Demands(LoD), and tele-conferences. In this paper, we introduce an adaptive multimedia synchronization algorithm using the level of buffers and load of servers, which are modeled and analyzed by ExSpect, a Petri net based simulation tool. In the proposed algorithm, the audio and video buffers are divided to 5 different levels, and the pre-defined play-out speed controller tries to make the buffer level to be normal in different temporal relations between multimedia streams using buffer levels and server loads. Because each multimedia packet is played by the pre-defined play-out speed, the media data can be reproduced within the permissible limit of errors while preserving the level of buffers to be normal. The proposed algorithm is able to handle and support various communication restrictions between providers and users, and offers little jitter play-out to many users in networks with the limited transmission capability. The performance of the developed algorithm is analyzed in various network conditions using a Petri net simulation tool.

• The korean journal of orthodontics
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• v.30 no.2 s.79
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• pp.245-260
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• 2000

The Objective of this research was to construct the multimedia database system that was necessary for the education of the practitioners and the students. To establish this system, there were technical problems as follows 1) The processing of the images, 2) The rapid processing of the information with the computer network, 3) The development of diagnosis tools, 4) The technique to establish the database system, 5) The link between the database system and the internet, and 6) The method to educate through many cases. The analysis for diagnosis and treatment planning were provided as two parts : model analysis and cephalometric analysis. As a model analysis, arch length discrepancy and Bolton tooth ratio were provided for the part of patient information. Cephalometric analyses were provided in the part of initial diagnosis. The Cephalometric analysis ver 2.0 and the PowerCeph pro 3.3.5 were used to show Tweed, Steiner and Jarabak analysis. In the main part, Kim's analysis and some measurements were added. In the post-treatment or retention part, we show the superimposition of the cephalometrics with which you can find the effectiveness of the various orthodontic treatment The address of this home page is "http://damis.snu.ac.kr/orthodontics"

• Journal of Korea Multimedia Society
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• v.20 no.8
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• pp.1456-1463
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• 2017

In recent times, IaaS (Infrastructure as a Services) have been rapidly evolving to allow developers to easily and efficiently access work in the server and network areas for development of a web of App based on cloud computing. In this study, we developed the collaborative image editing tool App based on Cloud-computing, by adopting AWS of representative company that develops IaaS. First, it is crucial to understand various situation conditions for representative infrastructure services: AWS, Azure and Google (GCP). This may have the effect of reducing manpower and development time, but as each company has different policy and technical support, we need a new study every time the environment changes of infrastructure services. We tried to develop a hybrid-App so that users with various devices can collaborate work each other by utilizing the infrastructure service AWS through the process of developing the image editing authoring tool based on the cloud computing. The future studies should continue about compatibility issues and support issues in order to minimize the problems of overseas infrastructure services, but we think that domestic cloud computing policies and developments should be urgently considered.

• Journal of Korea Multimedia Society
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• v.20 no.8
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• pp.1439-1446
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• 2017

Steady exercise or walking exercise is helpful for the treatment of chronic diseases or cancers. In this paper, I presented a smart poster to enable the patients to exercise while moving between the smart posters, dynamically, in order to provide better exercise effect to them. It can be a new form of exercise prescription that combines exercise with walking using smart posters. The personalized exercise prescription is downloaded from the management server in real time when the patient approaches, and induces the patient's exercise and walking. In addition, the smart poster helps patient to move to other posters in order to induce more walking exercise. To achieve this, I proposed a transfer protocol that autonomously exchanges session information between smart posters in this paper. Moreover, the smart poster based on Raspberry was implemented to verify validity of this protocol, and an experiment was conducted to measure the request and response time between smart posters in the implemented environment. In the experiment, when the other poster sent the message requesting the exercise session 100 times and received the response message, the 95 percentage of received messages had the response time within 0.05 seconds.

• Journal of Korea Multimedia Society
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• v.8 no.3
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• pp.413-420
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• 2005

In this paper, we describe a design and implementation of Web Services that convert WML(Wireless Markup Language) Page into .NET Mobile Web Page. The Web Services has an advantage that is available everybody without restriction oi platform and programming language. In this paper, we implement the Web Services Provider providing of converting system and the Web Services Consumer using this system. The Clients can get results of .NET Mobile Web Page without difficulty through Web Server because of implementation of Web Services Consumer using Web Services. Also the clients can develop new application using Web Services without respect of its implement process.

• Journal of Korea Multimedia Society
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• v.8 no.3
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• pp.355-361
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• 2005

This paper proposed a system collecting image information by agents in multi-threaded environment and then retrieving them with content based image retrieval. This system uses multi threads to retrieve web information effectively, then improves efficiency of CPU cycles to reduce latency time, which is the time requesting queries, executing communication processing 4hat the retrieval agents perform and filtering the retrieval results. Also, the agents for image retrieval use Java language, which is platform independent, to be suitable for distributed environment. Using JDBC to save the retrieved images, the agents are connected to database. The images themselves are stored in distributed agents' databases, and only the image indexes are stored in an index server so that the efficiency of storage and retrieval time can be improved.

• Journal of Korea Multimedia Society
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• v.2 no.1
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• pp.1-8
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• 1999

To provide information service with time constraints, it is required to support real-time information system for retrieval and update of distributed information. In this paper, we propose an information retrieval system model for internet. We design and implement a Domain Administration-Oriented search engine for the regional information network. Accordingly, an intelligent robot gathering and updating distributed information is implemented. And, in order to improves the performance of the system, a realtime robot control policy based on the loads of network and web server is proposed.

• Journal of Korea Multimedia Society
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• v.17 no.2
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• pp.160-169
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• 2014

Along the era of "Internet of Things (IoT)" in which the physical objects can be connected to the Internet, a smart power management system is proposed in this paper. This system consists of two modules, an electrical outlet device embedding the Wi-Fi capabilities and a web server supporting the management as well as monitoring of power consumptions. Also, with the proposed system, a customer can easily check the status of power consumption and turn on/off the sockets through the developed mobile website. The proposed system is designed to avoid firewall or PC setting problems involving a user's inconvenience.

• Journal of Korea Multimedia Society
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• v.18 no.11
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• pp.1367-1374
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• 2015

In this paper, we propose a model which can prioritize the performance improvement work by analyzing the major risks and their influence, which can cause performance degradation in the system and show an example of a performance improvement using this model. In presentation-tier, as a result of log data analysis before and after the performance improvement of key processes which handle financial transactions, this model brought the CPU utilization and memory enhancement in the performance improvement work of the financial system which was carried out by applying the proposed model. It has been confirmed that the entire end-user can be accommodated. In the web-tier, the available memory increased by 200MB and we were able to improve the server restart(Recycling) that was sustained in the existing system. In the business logic-tier, we have been able to see better figures after performance improvements through the graph which analyzes the log collected with the key performance counters such as CPU%, Batch Requests/sec. In the data-tier, it has been confirmed that CPU usage and standby operation were reduced and the throughput was found to increase.

• Journal of Korea Multimedia Society
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• v.21 no.10
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• pp.1162-1170
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• 2018

This paper presents an augmented reality system for multiple users. The proposed system performs ar image-based pose estimation of users and pose of each user is shared with other uses via a network server. For camera-based pose estimation, we install multiple markers in a pre-determined space and select the marker with the best appearance. The marker is detected by corner point detection and for robust pose estimation. the marker's corner points are tracked by optical flow tracking algorithm. Experimental results show that the proposed system successfully provides an augmented reality application to multiple users even when users are rapidly moving and some of markers are occluded by users.