• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.6
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• pp.2658-2679
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• 2018

This paper proposes a novel Random Scheduling Algorithm based on Subregion Coverage (RSASC), to solve the SET K-cover problem (an NP-complete problem). SET K-cover problem distributes the set of sensors into the maximum number of mutually exclusive subsets (MESSs) in such a way that each of them can be scheduled for lifetime extension of WSN. Sensor coverage divides the target region into different subregions. RSASC first sorts the subregions in the ascending order concerning their sensor coverage. Then, it forms the subregion groups according to their similar sensor coverage. Lastly, RSASC ensures the K-coverage of each subregion from every group by randomly scheduling the sensors. We consider the target-coverage and area-coverage applications of WSN to analyze the usefulness of our proposed RSASC algorithm. The distinct quality of RSASC is that it utilizes less number of deployed sensors (33% less) to form the optimum number of MESSs with the higher computational speed (saves more than 93% of the time) as compared to the existing three algorithms.

• Journal of Environmental Science International
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• v.28 no.11
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• pp.1027-1032
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• 2019

This study aimed to analyze the prioritized area for the functional change of agricultural reservoir according to the rapid urbanization and social changes through the mapping method. Changwon-si, Gimhae-si, and Jinju-si in Gyeongnam province were selected as the study area, considering the results of land-use and cluster analysis. As the planning unit of management area, watershed was used and land coverage map from 1975 to 2015 were analyzed for changes of land use. The reduction ratio (%) of farmland was calculated for identifying the changes in 2013 compared to 1975. As a result, the reduction ratio was 11.9% for Changwon-si, 12.2% for Gimhae-si and 9.3% for Jinju-si, and the number of watershed having functionally reduced potential-area was relatively high in the proportion to the city size.

• Journal of Biosystems Engineering
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• v.20 no.1
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• pp.36-46
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• 1995

The number of possible working days is one of the major factors for estimating the coverage area of a combine harvester. The percentages of possible working days at 24 locations were presented by analyzing the amount of rainfall during the working periods of rice harvesting from the end of September to the end of October for past 20 years. The percentages of possible working days ranged from 75% to 85% in most cases.

• Archives of Craniofacial Surgery
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• v.22 no.6
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• pp.341-344
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• 2021

Reconstruction of submental defects is a challenge that needs to be approached carefully, since many important anatomical structures are located in this small space. Both aesthetic and functional outcomes should be considered during reconstruction. In this report, we describe a case where a superficial branch of the transverse cervical artery (STCA) perforator propeller flap was applied for coverage of the submental area. An 85-year-old woman presented with a 3-cm ovoid mass on her submental area. We covered the large submental defect with a STCA rotational flap in a 180° propeller pattern. The flap survived well without any complications at 1 year of followup. A STCA propeller flap is a useful surgical option in reconstruction for defect coverage of the submental area.

• Journal of the Korea Society of Computer and Information
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• v.19 no.8
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• pp.63-71
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• 2014

This paper proposes an algorithm that forms the clusters on the basis of hop distance in order to improve the actor coverage and connectivity in the sink-based wireless sensor and actor networks. The proposed algorithm forms the clusters that are distributed evenly in the target area by electing the CHs(Cluster Heads) at regular hop intervals from a sink. The CHs are elected sequentially from the sink in order to ensure the connectivity between the sink and the actors that are located on the CHs. Additionally, the electing are achieved from the area of the higher rate of the sensors density in order to improve the actor coverage. The number of clusters that are created in the target area and the number of the actors that are placed on the positions of the CHs are reduced by forming the clusters with regular distribution and minimizing the overlap of them through the proposed algorithm. Simulations are performed to verify that the proposed algorithm constructs the actor network that is connected to the sink. Moreover, we shows that the proposed algorithm improves the actor coverage and, therefore, reduces the amount of the actors that will be deployed in the region by 9~20% compared to the IDSC algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.1
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• pp.140-146
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• 2018

Recently, VLC(Visible Light Communication) fusing with LED(Light Emitting Diode) used in indoor lighting and wireless communication technology has attracted attention. However, the VLC can communicate only within the coverage to measure the optical signal and the communication disconnection phenomenon is occur in the NLoS(Non-Line-of-Sight) area. In this paper, we propose VLC relay module to extend the coverage of VLC and improve the communication disconnection phenomenon in NLoS area. The proposed VLC relay module transmits the packet received from the transmitter to the VLC relay module and receiver. The experiment was carried out by installing one VLC transmitter and three VLC relay modules, communication coverage expansion and the improvement of communication disconnection phenomenon in the NLoS were confirmed by the increase of the VLC relay module. Also, we confirmed that the optical signal measurement performance is improved 2.4 times by using the dual sampling method.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10A
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• pp.1521-1528
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• 2000

In this paper we analyze the performance of a DS/CDMA system in LEO mobile satellite channels. The channel uses the Extended Suzuki model which is the product of a Rician distribution having a LOS component and a lognormal distribution due to shadowing. We assume that the signal transmitted from the satellite to the mobile undergoes the same fading for the whole coverage of signal's beam. The average bit error probabilities of double coverage system is calculated in this paper. The interference resulting from the reference satellite is calculated for mobile located in the middle of the double coverage region whereas the additive interference from next-satellite is included for mobile located in the edge of the double coverage region. The performance of the mobile's receiving signal is dependent on shadowing and the interference of the next-satellite. We can obtain an obtain an improved average bit error probability by using dual diversity over the conventional correlated receiver for similar shadowing conditions in the coverage area of the satellite channel.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2001.10a
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• pp.6-12
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• 2001

Korea government decided to provide the NDGSP service and the conceptional design report are presented here. The coverage of the exiting MDGPS stations of inland area is measured and the positions and characteristics of additional inland NDGPS sites are proposed for the full-coverage of inland areas of Korea.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2001.10a
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• pp.7-12
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• 2001

Korea government decided to provide the NDGSP service and the conceptional design report are presented here. The coverage of the exiting MDGPS stations of inland area is measured and the positions and characteristics of additional inland NDGPS sites are proposed for the full-coverage of inland areas of Korea.

• The Journal of the Korean dental association
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• v.47 no.3
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• pp.122-130
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• 2009

For the successful guided bone regeneration(GBR) of maxillary bony defect, proper soft tissue coverage is one of the most important things. Soft tissue dehiscence can be most common reason of osseous reconstruction failure. If a vascular supply to the graft should not develop from the host tissue, then the graft may also foil. Both of these prerequisites can be aided by judicious use of the buccal fat pad(BFP). Many methods for adequate soft tissue coverage have been proposed and the use of the BFP is one of them. BFP is useful in posterior maxillary area, can cover larger area and have higher blood flow than other methods. so the use of the BFP may offer protection and early blood supply to maxillary bone graft. This report describes the history, anatomy, blood flow, and clinical usefulness with two clinical cases.