• The Journal of the Korea Contents Association
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• v.12 no.4
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• pp.10-19
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• 2012

Seamless streaming of multimedia content that ensures Quality of Service over heterogeneous networks has been a desire for many multimedia services, for which the multimedia contents should be adapted to usage environments such as network characteristics, terminal capabilities, and user preferences. Scalability in video coding is a good feature to meet the requirement of heterogeneous networks. In this paper, we propose a dynamic adaptation scheme of H.264/AVC SVC bit-stream using the MPEG-21 Digital Item Adaptation (DIA) tool. MPEG-21 DIA framework provides systematic solutions in choosing an adaptation operation to given conditions and supports interoperable video adaptation. The experiment results show that the proposed adaptation scheme provides QoS-enabled delivery and consumption of SVC with time-varying constraints of network, terminal, and user preference, in a robust and efficient way. In particular, the proposed adaptation scheme is proved to work well with very low delay under the condition that the variation rate of the given network bandwidth is upto 62%.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.6
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• pp.1-16
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• 2013

Smartphones and tablets including phone, calendar are the necessities of modern man. They are one of the MN(Mobile Node), each with wireless network capabilities. Necessities of modern human MNs are almost included cellular module available in LTE/3G and Wi-Fi module for high-speed Internet. Until now, MN mobility management is handled, but using network-based mobility management in this paper. Then, carriers can manage and maintain the network for low-cost. In addition, it was considered that use a lot of modern people with Wi-Fi and LTE/3G, and using Cross-Layer-Based handoff.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.341-345
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• 2010

WMN is one of efficient solutions to provide Internet services for users by forming wireless backbone networks with wireless links. The dominant technology for WMNs is the IEEE 802.11, which provides multi-channel and multi-rate capabilities. One of important issues in WMNs is the network capacity and it is essential to design a multi-channel protocol that leverages the network capacity. However, when wireless links that use different data rates operate on the common channel, the performance of high-rate links is severely degraded by the presence of the low-rate links, which is often referred as performance anomaly. In this paper, we propose a Tree-based Channel Assignment (TreeCA) protocol to mitigate the performance anomaly problem by distributing data rates over multiple channels. TreeCA performs channel assignments based on the tree WMN architecture to accommodate the Internet traffics efficiently. Parent nodes on the tree distribute their child nodes over multiple channels so that the performance anomaly is reduced. Through simulations, we observed that the proposed TreeCA outperforms the existing multi-channel protocols for WMNs.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.405-406
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• 2012

A sensor network is composed of a large number of sensor nodes which have sensing, computation and wireless communication capabilities. The sensor node sends such collected data, usually via radio transmitter, to a command center (sink) either directly or through a data concentration center (a gateway). These sensor networks can be used for various application areas such as health, military, home network, managing inventory, monitoring disaster areas and so on. Moreover, owing to the rapid growth of mobile technology, high-performance smartphones are widespread and in increasing cases are utilized as a terminal device. In this paper, we propose a home management system using smartphone and sensor networks.

• The Transactions of the Korea Information Processing Society
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• v.6 no.6
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• pp.1493-1501
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• 1999

For the multimedia conference in various networks, international standard works make progress with H and T series. T.120 series are recommended for multipoint data conference in various networks, but its demerit is not supported with video and audio capabilities. H.32X series are recommended for videoconference in various networks. To solve these problems, the combination of H.32X and T.120 are used. But many difficulties exist for consistent control. To solve these problems, T.130, T.131 and T.132 standardizations are made progress, and these are analyzed and implemented over LAN(Local Area Network). Our system introduced in this paper is currently operated on LAN, but can be operated with mixed networks with addition of underlying network dependent protocols.

• Journal of Information Management
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• v.37 no.2
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• pp.93-107
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• 2006

There are some questions about the way to monitoring the regional innovative activities in a specific field because of decision-making for raising regional specialized industry. Numerous studies have been conducted in the past using patent statistics to explain and compare the innovative capabilities of districts, regions and countries. The prior method of calculating the regional distribution of patent counts is to assign the patents to districts by assignee's address, which was not proper, in the case of larger firms's headquarters, holdings or subsidiaries, to mislead in geographical terms. So the regional distribution of patent was counted for a specific technology area, electric device field(H01 IPC classification), by inventors' residential addresses. Then the interregional structure was investigated by analysing the relations of co-inventors' regions by individual patent using a network analysis tool.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.12B
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• pp.1112-1122
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• 2008

This paper reviews the Parlay X and proposes SIP multimedia session control mechanism which is able to be implemented over IMS using Extended Call Control APIs of Parlay X. Parlay X is one of the industrial standards of Open API in the telecommunication to open network resources and capabilities to third party service providers. In this paper, SIP session control mechanism is described by depicting call flows of basic and essential session handling methods including session initiation, transfer, restoration, and termination. We also show how easy Parlay X Extended Call Control APIs can be used for the purpose of complicated calls handling in the IT applications. To verify feasibility of the blended services based on convergence of telecommunication and internet with regard to performance, we accomplish experimental performance of Extended Call Control APIs from IT application through open service gateway. We show Open API could be applied to next generation network based on IMS without serious degradation of the network performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39C no.11
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• pp.1139-1145
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• 2014

In shipyard site, a ship is constructed by integrating lots of modules that are made in several sites with different capabilities and specifications. Recently, it needs to make a shipyard to be smart communicating various multimedia information with wired and wireless broadband networks between hierarchical shipyards. In this paper, we propose an additional function of an LTE femtocell local gateway at a remote shipyard, an information exchange method between hierarchical shipyards, and an offload method to separate the general traffic. To reduce traffic of duplicated requests in shipyard, we apply a D2D communication scheme for supporting communication between shipyard equipments without IP service network. Hence, it is expected to increase the productivity of shipyard industry with mobile communications, D2D and broadband Internet technologies.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.4
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• pp.679-686
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• 2020

With global data totals expected to grow to 175 ZB by 2025, data processing capabilities in the network area are becoming more important. In particular, data centers are becoming more stubborn as data usage increases, and the load generated by incoming data should be appropriately distributed to reduce costs and efficiently operate. The SDN technology, which emerged to overcome the limitations of the existing network system, removes rigidity of the Legacy system by separating H/W and S/W from the network equipment, and can be effectively applied to load balancing in the data center using S/W-based flexibility. In this paper, we propose ways to increase efficiency by classifying data received from users by type by utilizing SDN technology, and transmitting and processing classified data in order of response speed of servers in the data center.

• Journal of the Korea Convergence Society
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• v.10 no.11
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• pp.85-93
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• 2019

Despite its matchless position in the global semiconductor industry, Korea has not distinguished itself in the semiconductor equipment sector. Semiconductor cleaning equipment is one of the semiconductor fabrication equipment, and it is expected to be more important along with the advancement of semiconductor fabrication processes. This study attempts to analyze technology competitiveness of major countries in the sector including Korea, and explore specialty sub-areas of the countries. For this purpose, we collected patents of semiconductor cleaning equipment during the last 10 years from the US patent database, and implemented quantitative patent analysis and co-classification network analysis. The result shows that, the US and Japan have been leading the technological progress in this sector, and Korea's competitiveness has lagged behind not only the leading countries but also its competitors and even latecomers. Therefore, intensive R&D and developing technological capabilities are needed for advancing the country's competitiveness in the sector.