• The Journal of the Korea Contents Association
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• v.7 no.5
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• pp.128-137
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• 2007

Digital cinema industry in Korea is developing very fast. It makes the structure of Korea film industry being changed with outstanding D.I process, reduction of production cost, the convenience of distribution & screening and easy transferring to other platforms. The main reason of this fast development is due to Korea film industry monopoly structure by a few companies. In addition, Huge Korea mobile communication companies are pushing Digital cinema industry to go faster with their own net work and platforms. However, Korea digital cinema industry still has problems like standardization in releasing, the lake of data in post-production and overuse in production. It is the time that we have to think about best way for the healthy development of Korea digital cinema industry more than the fast development of it.

• Journal of KIISE:Databases
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• v.33 no.5
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• pp.476-485
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• 2006

The Resource Description Framework(RDF), which emerged with the semantic web, is settling down as a standard for representing information about the resources in the World Wide Web Hence, a lot of research on storing and query processing RDF documents has been done and several RDF storage systems, such as Sesame and Jena, have been developed. But the research on updating RDF documents is still insufficient. When a RDF document is changed, data in the RDF triple store also needs to be updated. However, current RDF triple stores don't support incremental update. So updating can be peformed only by deleting the old version and then storing the new document. This updating method is very inefficient because RDF documents are steadily updated. Furthermore, it makes worse when several RDF documents are stored in the same database. In this paper, we propose an incremental update algorithm on RDF, documents in triple stores. We use a text matching technique for two versions of a RDF document and compensate for the text matching result to find the right target triples to be updated. We show that our approach efficiently update RDF documents through experiments with real-life RDF datasets.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.506-512
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• 2016

Recently, energy harvesting technology is considered as a tool to improve the lifetime of sensor networks by mitigating the battery capacity limitation problem. However, the previous work on energy harvesting has failed to provide practical information since it has assumed an ideal channel knowledge model with perfect channel state information at transmitter (CSIT). This paper proposes an energy efficient resource allocation scheme that takes account of the channel estimation process and the corresponding estimation error. Based on the optimization tools, we provide information on efficient scheduling and power allocation as the functions of channel estimation accuracy, harvested energy, and data rate. The simulation results confirm that the proposed scheme outperforms the conventional energy harvesting networks without considering channel estimation error in terms of energy efficiency. Furthermore, with taking account of channel estimation error, the results provides a new way for allocating resources and scheduling devices.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.04a
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• pp.357-362
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• 2004

Due to the rapid growth of Chinese ports, currently, research for the improvement of competitiveness of Busan port have been intensively studied. These research have mostly evaluated or analyzed competitiveness of ports, and then, based on results of analysis, have suggested some strategies for enhancing competitiveness of Busan port. However, although implications of these previous studies are practically available to build policies for Busan port, basic studies such as identification of port competitiveness( or port selection) related factors for reasonable evaluation and analysis which have contributions in academic area have been very rare. The primary objective of this study is to investigate port selection criteria, based on empirical data. Especially, in this study, we classify internal／external factors, and present importances of external factors that have yet to be empirically identified in previous studies.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.12
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• pp.2387-2394
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• 2016

It is important to select the most appropriate channel for efficient transmission of massive data in wireless sensor network. In the fixed channel method for wireless sensor node, shortage of frequency may be a major constraint to support a variety of environments. In this paper, the method that seeks common channels between two nodes without common control channels in the existing wireless cognitive radio network is introduced in order to use efficiently the channel of wireless sensor network. The problem of existing method shows the severe degradation of performance that is caused by interference of linkage between selected channels, so that the sequential algorithm is suggested to improve the performance. From the results of computer simulation, the suggested method shows that the link can be set 50% faster than the other methods as the number of links increases because the beacon packet waiting time caused by the interference decreases remarkably.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.1
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• pp.35-41
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• 2017

To solve the shortage of radio spectrum and utilize spectrum resource more efficiently, cognitive radio technologies are proposed, and many studies on cognitive radio have been conducted. Multi-hop routing is one of the important technologies to enable the nodes to transmit data further with lower power in ad-hoc cognitive radio networks. In a multi-channel cognitive radio networks, each channel should be allocated to minimize interference to primary users. In the multi-hop routing, channel allocation should consider the inter-channel interference to maximize network throughput. In this paper, we propose multi-channel scheduling scheme which minimizes inter-channel interferences and avoids collision with primary users for the multi-hop multi-channel cognitive radio networks. The proposed scheduling is designed to determine both of routing path and channel selection. The performance of proposed channel allocation scheme is evaluated by the computer simulation in the aspect of capacity and collision rate.

• Journal of Korea Game Society
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• v.6 no.3
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• pp.13-22
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• 2006

Games such as sports, RTS, RPG, which teams of players play, require advanced artificial intelligence technology for team management. The existing artificial intelligence enables an intelligent agent to have the autonomy solving problem by itself, but to lack interaction and cooperation between agents. This paper presents "Level Unified Approach Method" with effective role allocation and autonomy in multiagent system. This method allots sub-goals to agents using role information to accomplish a global goal. Each agent makes a decision and takes actions by itself in dynamic environments. Global goal of Team coordinates to allocated role in tactics approach. Each agent leads interactive cooperation by sharing state information with another using Databoard, As each agent has planning capacity, an agent takes appropriate actions for playing allocated roles in dynamic environments. This cooperation and interactive operation between agents causes a collision problem, so it approaches at tactics side for controlling this problem. Our experimental result shows that "Level Unified Approach Method" has better performance than existing rental approach method or de-centralized approach method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.47 no.3
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• pp.1-7
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• 2010

Cognitive Radio, which adaptively utilizes the vacant licensed spectrum band, is considered as an effective way to alleviate the scarcity of spectrum resource shortage. In order to guarantee the non-interference transmission of primary system, spectrum sensing, especially in quiet period, is proposed. However, it is insufficient to avoid the unacceptable interference caused by Cognitive Radios, because the primary user may appear anytime that is unpredictable. In this paper, we address the deficiency of conventional spectrum sensing and propose a novel Cognitive Radio receiver structure with monitoring function block to detect the appearance of primary user in a real-time manner. Simulations prove that the proposed eigenvalue based detection method together with the two-threshold decision procedure performs properly.

• Journal of Broadcast Engineering
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• v.16 no.2
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• pp.305-318
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• 2011

Since switched digital video (SDV) provides specific programs only to the subscribers who request the programs, SDV has attracted considerable interest of MSOs for bandwidth efficiency. In North America, MSOs service over 2.3 million households with the SDV for cable networks. In Korea, since demand of HD program, high-speed Internet, VoD, and VoIP is noticeably rising, the SDV is considered as the alternative for bandwidth saving and efficient managing. In this paper, the characteristics, operating structure, and bandwidth saving of the SDV are discussed and technical requirements for the SDV are also introduced. The channel switching performance and stability of the SDV are analyzed through the test-bed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.05a
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• pp.433-436
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• 2013

Massive MIMO communication system with huge antennas has been attracting intensive attention as one of key technologies to increase the spectral efficiency. Many previous studies investigated single user Massive MIMO scheme in cellular downlink. Recently, however, intensive researches on multiuser-based Massive MIMO are performed to overcome the problem caused by the limited number of antennas in mobile stations. Although the Massive MIMO scheme based on huge number of antennas inevitably causes hardware and computational complexity in baseband and radio frequency (RF) elements, the problem can be mitigated without serious performance degradation by limiting the number of baseband and RF elements below the number of transmit antennas of base station and opportunistically selecting transmit antennas according to channel states, where the number of selected antennas corresponds to the number of baseband and RF elements in base station. Accordingly, this paper proposes a simple antenna selection scheme for multiuser-based Massive MIMO systems. Our simulation results indicate that the proposed antenna selection scheme can achieve comparable performance to the conventional scheme without antenna selection.