• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.5B
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• pp.721-733
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• 2010

In this paper, we propose a scalable content-based routing scheme for the tactical mobile ad-hoc networks where the nodes usually move together forming a group. Our scheme is classified as a content-based routing scheme based on publish and subscribe model. The nodes compose a cluster according to their position and interest. Our scheme allows multi-level cluster nesting. As a publish/subscribe model does, each node announces its interest to the cluster head who aggregates and announces the interests from cluster members to its neighbor cluster head. Actual data messages are delivered to the end node via cluster header in the reverse direction of the interest announcement. Using Qualnet simulator, we evaluated the performance of our scheme in comparison with two well-known content-based routing schemes. Simulation results show that our scheme maintains higher message delivery ratio as number of nodes increases whereas the two schemes show much lower delivery ratio. In addition, as the group mobility gets faster our scheme incurs less or similar control message overhead compared with the two schemes.

• Journal of the Korea Society of Computer and Information
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• v.12 no.6
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• pp.187-192
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• 2007

Conference focus maintains and manages SIP(Session Initiation Protocol) signal connections with total conference participants, and it plays core functions of conference server. When the number of conference participants increases, conference focus restricts scalability of conference as increasing quantify of messages for processing. In this paper, to solve this problem. we propose a user system(conference information agent), which receives conference information from the conference focus and transfers them to the participants it manages. And we design and implement the total system including conference focus. When the conference information agent subscribe to the conference focus, it shows its possession of agent capability and capacity by using SIP SUBSCRIBE message. The conference focus informs to the other party by SIP response message that it was chosen as a conference information agent, and after that the conference focus sends all conference notification messages to it. So load of the conference focus can be reduced by this method. Finally, we have analyzed the performance of our system by experiments.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1359-1370
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• 2009

In wireless sensor networks, data dissemination is based on data-centric routing that well matches the publish/subscribe communication paradigm. The publish/subscribe paradigm requires decoupling properties: space, time, and synchronization decoupling. For large-scale applications, the three decoupling properties provide scalability and robust communication. However, existing data dissemination schemes for wireless sensor networks do not achieve full decoupling. Therefore, we propose a novel data dissemination scheme that fully accomplishes the three decoupling, called ARBIETER. ARBITER constructs an independent network structure as a logical software bus. Information interworking between publishers and subscribers is indirectly and asynchronously performed via the network structure. ARBITER also manages storage and mapping of queries and data on the structure because of supporting different time connection of publishers and subscribers. Our simulation proves ARBITER show better performance in terms of scalability, network robustness, data responsibility, mobility support, and energy efficiency.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.3B
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• pp.493-502
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• 2010

In this paper we propose a scalable sensor network system that makes mesh network among the sink nodes to solve the scalability problem of existing sensor network which is caused by multi-hop networking between the sensor nodes. In the proposed system, the sink nodes have the wireless networking ability to communicate with another sink nodes in mesh fashion, and with the monitoring nodes which is located in the local area or internet area. Especially, the system includes L4(Application Layer) routing mechanism that provides subscribe/publish service to serve selective transmission of sensor data to the specific monitoring nodes. The collected sensor data is transmitted to the monitoring nodes when the sensor data is matched with the monitoring node's interesting value.

• The Journal of the Korea Contents Association
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• v.17 no.5
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• pp.68-79
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• 2017

This study explored the relationship between users' integrated estimates (motivation, activity, & performance) of telecommunication companies' CSR & service qualities and their preference and intention to subscribe telecommunication services. The data were collected from 637 college students for understanding the relationship among variables in KT and SKT. The result indicates that social benefit motivation, legal/moral activity, and social performance of the integrated CSR estimates affected their preference. The estimate of philanthropic activity, however, was not significantly affected on preference. On intention to take telecommunication services toward KT and SKT, the estimate of social performance was only a significant variable in KT and legal/moral activity and social performance were statistically significant in SKT. Generally, the estimate of service quality was the most affective factor toward telecommunication preference and intention to subscribe its services.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.186-190
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• 2008

This paper analyzes previous work on publish/subscribe in mobile ad-hoc networks with respect to collaboration methods among distributed event brokers. Our experiments suggest that approaches building event delivery structures are suitable for a scenario where there are events of various types each of which is consumed by a few subscribers. However, these approaches based on independent periodic exchange of network topology information may fail to reflect the up-to-date information when building event delivery paths. For this reason they do not correctly recover a broken path caused by node mobility, which results in lower event delivery rates. This paper proposes a scheme for building and maintaining event delivery paths based on advertisements initiated by and hence propagated from the root node. This guarantees correct recovery of event delivery paths within each period. Our experiments show that, our proposed scheme gives a better event delivery ratio with lower overhead.

• Journal of the Korea Society of Computer and Information
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• v.18 no.4
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• pp.79-85
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• 2013

In SIP(Session Initiation Protocol) environment, the presence server should process SIP SUBSCRIBE request messages including multiple presence resources addresses from users, and also precess massive notification messages from the subscribed presence resources. The load of the presence server increases as number of users increase, and it limits system extendability. Therefore a new multiple presence servers architecture has been suggested in this research. In this architecture presence servers can be added dynamically and each server's load can be controlled effectively as number of users increase. Each presence server can monitor current load status of entire presence system by using presence event notification package which newly has been suggested in this paper. When a particular presence server's load increases over predefined limit, the presence service processing is distributed by selecting a server which has the smallest load, or by generating a new server dynamically. In this system the overall load of the entire system can be controlled optimally and extendability of the system can be increased. For this purpose a new presence event notification package and presence information data format have been suggested. The performance of the proposed system has been evaluated by experiments. They shows 44.3% increase in SUBSCRIBE message processing time, and 43.1% increase in Notification message processing time.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.6
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• pp.225-233
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• 2010

Recently, in the field of Smart Grid, Smart Home Network, Ubiquitous Computing, etc. we have continued to study Smart Information Monitoring Technology(SIMT) which exchange, control and monitor information collected and processed by need in real-time and two-way. In this paper, we understand application products or recent trends of SIMT for Energy, U-Farm, Vehicle Information and Home Network. Specially, we explain Google PowerMeter which exchange information with Smart Meter of core part of the smart grid at real-time, Real-time Monitoring System(RMS) for U-Farm, RMS for vehicle status Information. we subscribe Smart Information Monitoring Technology application based on ZigBee of low price, low power or related work. Finally we subscribe actual proof construction situation of Jesu for smart grid.

• Journal of KIISE:Computing Practices and Letters
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• v.14 no.2
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• pp.211-215
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• 2008

the data-centric publish/subscribe middle-ware is suitable for a communication environment in which various devices dynamically forms a network domain and same type of data are frequently exchanged. For this purpose, OMG has standardized DDS (Data Distribution Service) specification. In this study, we designed the RiTiCoM, data distribution service system that observes the OMG DDS (Data Distribution Service) standard specification and supports the automation of system management, and analyzed the performance and compared with the JMS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1077-1083
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• 2000

With rising demand of Internet Service, the existing communication for users (aced the restricted capability and speed, and also failed to satisfy consumer's desire for providing service-quality to them. It can be accomplished the broad-band on subscribe-line to offer various multimedia service to subscriber. But it takes a lot of times and costs. Consequently, it stands out the most economic subscribe-line for acheving a broadband scheme that new transmission technology can be realized the high-speed data communication as the present telephone-line and telephone by the general public of FTTH(Fiber To The Home). As using the pseudo line, this paper have the result that the mesured speed was improved by connecting a variable resistor on the line.