• The Journal of Korean Institute of Communications and Information Sciences
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• v.33 no.3A
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• pp.219-224
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• 2008

In the c-DSDV routing protocol proposed to improve the scalability of DSDV, clusterheads manage a routing table that has only clusterheads as potential destinations and flood update request message to its neighbor clusterheads periodically or at the time of topology change. Accordingly, the convergence range of topology change by a single update request message was expanded nine times as wide as that of DSDV, increasing routing correctness; however, c-DSDV suffers from the congestion of clusterheads since data packets always go through clusterheads of the clusters on the routing path. To improve this problem, we propose an adaptive routing scheme that judges if detouring clusterhead is possible on the fly while packets are forwarded. As a result, a routing path length is shortened and an end-to-end delay is improved by the reduced queue length. It shows that the end-to-end delay is reduced by almost 40% through 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.201-210
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• 2019

This paper proposes the AMCS(Agricultural Machine Control System that distinguishes farms using satellite photos or drone photos of farms and controls the self-driving and operation of farm drones and tractors. The AMCS consists of the LSM(Local Server Module) which separates farm boundaries from sensor data and video image of drones and tractors, reads remote control commands from the main server, and then delivers remote control commands within the management area through the link with drones and tractor sprinklers and the PSM that sets a path for drones and tractors to move from the farm to the farm and to handle work at low cost and high efficiency inside the farm. As a result of AMCS performance analysis proposed in this paper, the PSM showed a performance improvement of about 100% over Dijkstra algorithm when setting the path from external starting point to the farm and a higher working efficiency about 13% than the existing path when setting the path inside the farm. Therefore, the PSM can control tractors and drones more efficiently than conventional methods.

• Journal of IKEEE
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• v.26 no.1
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• pp.89-94
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• 2022

The W-band (75-110GHz) is a band that can utilize at least 10 times more bandwidth than the existing 5G band. Therefore, it is one of the bands suitable for future mobile communication that requires high speed and low latency, such as virtual and augmented reality. However, since the wavelength is short, it has a high path loss and is very sensitive to the atmospheric environment. Therefore, in order to develop a W-band communication system in the future, it is necessary to analyze the characteristics of path loss according to the channel environment. In this paper, to analyze the characteristics of the W-band path loss, the random forest technique was used, and the influence of the channel parameters according to the distance section was analyzed through the path loss data according to various channel environment parameters. As a result of the simulation, the distance has the highest influence on the path loss in the short distance, and the other channel environment factor is almost ignored. However, as the distance section became longer, the influence of distance decreased while the impact of clutter and rainfall increased.

• Journal of Korea Port Economic Association
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• v.23 no.4
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• pp.196-215
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• 2007

The Representatives of Korea & India hold The Sixth negotiation for conclusion of Korean-India CEPA(Comprehensive Economic Partnership Agreement) at IFANS(Institute of Foreign Affairs & National Security) in Seoul at April 4, 2007. The latest, India is paid attention by the citizen of the world as the leading country that it lead the 21C's world economic with the China, India is called one of the BRICs and Chindia countries. Now, the concern of the citizen of world inclines huge potential energy of India. It is that time, we must change our concern from Chinas to India slowly. This paper put emphasis the point that we have to move switch over the focus of our study from to India, now.