• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1336-1348
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• 2009

In this paper, we propose an energy-aware multi-tree video multicast scheme for wireless ad hoc networks. Some network nodes may have energy enough to receive and forward the whole video content whereas some may not. Even though the video quality may vary depending on the remaining energy, our scheme enables the low-energy nodes to join the video multicast session. The video stream is split into a set of multiple and independent descriptions by MDC (Multiple description coding) scheme. Each description corresponds to a substream and number of substreams determine the video quality. The member nodes determine how many substreams it would receive depending on the remaining energy and expected amount of packets per substream. So does the intermediate tree nodes. That builds a tree per substream and multiple trees per session. The data source disseminates each substream through corresponding tree. The video quality of the member nodes varies according to number of participating trees. We evaluate the performance of our scheme by simulation. Our scheme showed better peak signal to noise ratio and extended the lifetime of the network nodes compared with MAODV, which builds a single tree, and MT-MAODV, which builds multiple trees but does not consider the available energy.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.5
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• pp.514-520
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• 2018

Presence service provides various information about users such as locations, status of on/offline and network access methods, and number of presence resources required by each users increases largely in mobile environment. Therefore an effective method which can reduce load of presence servers is needed. In this paper, a large scale distributed presence service system which can distribute effectively total presence system load of presence servers using message control session has been presented. This large scale distributed presence service system provides various presence information for massive volumes of users. In this study, a new message control session architecture which can dynamically distribute loads of the presence servers to multiple servers has been presented, and a new presence information data architecture for controlling load of the presence servers has been designed. In this architecture, each presence server can exchange current load level in real time to get variance of the total system load change according to user numbers, and can distribute system load to maintain load level of each server evenly. The performance of the proposed large scale distributed presence service system has been analysed by experiments. The results has been showed that average presence resource subscription processing time reduced from 42.6% to 73.6%, and average presence notification processing time reduced from 37.6% to 64.8%.

• Asia pacific journal of information systems
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• v.25 no.3
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• pp.423-444
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• 2015

Ideation is a process of generating new ideas or solutions using online crowd-sourcing technologies. This process has the potential to change the ways by which government agencies innovate and solve problems. Although increasingly more government agencies are implementing online ideation programs to tap into their employees' ideas and creativity, little is known about the unique challenges and effective practices of such programs. Thus, many government agencies are undergoing trial and error and often reinventing the wheel. This research aims to address this problem. By analyzing a focus group session and four cases of U.S. federal government ideation programs designed for their employees, this research identifies important organizational and technological challenges and effective practices. Furthermore, effective practices are grouped into different phases of ideation process and strategic vs. tactical levels to provide more meaningful and actionable insights. This research is an important step towards building a theoretical foundation for government ideation programs. The implications and limitations of this study are discussed.

• Journal of Biomedical Engineering Research
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• v.28 no.5
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• pp.585-589
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• 2007

This study proposes an automated pegboard utilizing the RFID system with multiple reader antennas for the rehabilitation services and the occupational therapy. The system automates the scoring by detecting the plugging correctness as well as the plugging status. It also aims to increase the patient's interest and the functional intelligence. The system was prototyped and tested for the automatic capability of the scoring the session time and success rate. The proposed system will be served as the typical example for the ubiquitous rehabilitation devices.

• ETRI Journal
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• v.28 no.6
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• pp.709-720
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• 2006

In this paper, we suggest a simple and efficient multiple-forwarder-based file distribution method which can work with a tree-based application layer multicast. Existing multiple-forwarder approaches require high control overhead. The proposed method exploits the assumption that receivers join a session at different times. In tree-based application layer multicast, a set of data packets is delivered from its parent after a receiver has joined but before the next receiver joins without overlapping that of other receivers. The proposed method selects forwarders from among the preceding receivers and the forwarder forwards data packets from the non-overlapping data packet set. Three variations of forwarder selection algorithms are proposed. The impact of the proposed algorithms is evaluated using numerical analysis. A performance evaluation using PlanetLab, a global area overlay testbed, shows that the proposed method enhances throughput while maintaining the data packet duplication ratio and control overhead significantly lower than the existing method, Bullet.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2252-2258
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• 2016

CCMP(centralized conferencing manipulation protocol) enables adding and removing conference participants, changing their roles, adding and removing media streams in conference system. In this paper, by using extended CCMP, a new distributed conference system architecture which can be used to multiple servers distributed conference system in SIP(session initiation protocol) environment has been presented. In this study, according to increasing number of participants, a new extended CCMP architecture which can distribute conference system loads to multiple servers dynamically to decrease loads of servers has been designed. This extended CCMP architecture also can add dynamically new servers from the prepared servers pool. Furthermore, new conference information data format which can represent extended CCMP has been designed, and exchange procedures of extended CCMP control messages which can distribute loads between servers have also been presented. The performance of the proposed system has been analysed by simulation.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.3
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• pp.224-230
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• 2019

In this paper, a new multiple servers conference service system using media control channel/distributed conference manipulation architecture has been presented. This conference service system can handle loads effectively from many conference participants. In this suggested architecture, media control channels are established between conference server, and distributed conference manipulation messages for distributing system loads are exchanged through this channels. These messages are transported between servers using media control channel created after stable transport sessions, and can be used to process server loads according to participants effectively. So this method can be used to implement large scale conference service system. For these purposes, formats of distributed conference manipulation messages which transmitted through media control channels are designed. and messages exchange procedures between conference servers are also presented. The performance of the proposed conference service system has been analysed by experiments, and the results show that the performances are improved according to participants.

• Women's Health Nursing
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• v.9 no.3
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• pp.277-286
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• 2003

Purpose: The purpose of this study was to probe the effect of foot reflexology education program on nursing students with constipation, anxiety and depression. This study was a quasi-experimental study of pre-test and posttest design on non-equivalent control group. Method: The data of this study were collected from October 28, to December 14, 2002. The subjects consisted of 61 nursing students (experimental group: 31, control group: 30) with constipation, anxiety and depression. 31 out of them were devided into the experimental group and received foot reflexology education program that was authorized by the World Foot Reflexology Association and made to suit for the subjects by the author for 6weeks composed of 2 weeks theory and of 4 weeks practical skill on the program. The effect of the program was measured by Bowel Function Assessment Form for constipation, State Anxiety Inventory, and Beck Depression Inventory. Data were analyzed by t-test, $x^2$-test, Repeated measures ANOVA, Bonferroni multiple comparison using SAS/PC 8.12 program. Result: After all session of treatment, the score of bowel function assessment were significantly decreased in the experimental group compared to the control group. Outcomes of 6 and 7 weeks were significantly different from those of pre-experiment. After all session of treatment, anxiety states were significantly decreased in the experimental group compared to the control group. Outcomes of 7 weeks were significantly different from those of pre-experiment. After all session of treatment, depression states were significantly decreased in the experimental group compared to the control group. Outcomes of 6 and 7 weeks were significantly different from those of pre- experiment. Conclusion: The results are suggested that the foot reflexology education program might improve the bowel function, anxiety and depression for the nursing students with constipation, anxiety and depression.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.6
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• pp.647-656
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• 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
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• v.18 no.9
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• pp.2169-2175
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• 2014

In this paper we have proposed a new distributed architecture of session-based instant message system, in which multiple servers can distribute loads effectively to improve system extendability. The server of session-based instant message system should manage SIP sessions to transfer instant message with multimedia data to each users, and it should process large amount of presence informations from each users. Therefore load of the server should be distributed as the number of users increases. In our system, when server load increases according to large user numbers, the load are distributed by selecting a server with the lowest load value, or new server is created to allocate the message processing. Therefore the overall load of instant message system can be dynamically distributed. A new presence information data format with added elements for controlling server load has been designed for this purpose, and SIP messages exchanging procedure between servers and users has been also suggested. The performance of our proposed system has been analysed by simulation, and showed improvement of performance.