• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.33 no.6
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• pp.605-614
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• 2015

Drone imaging, which is more cost-effective and controllable compared to airborne LiDAR, requires a low-cost camera and is used for capturing color images. From the overlapped color images, we produced two high-resolution digital surface models over different test areas. After segmentation, we performed tree identification according to the method proposed by , and computed the tree height and the canopy crown size. Compared with the field measurements, the computed results for the tree height in test area 1 (coniferous trees) were found to be accurate, while the results in test area 2 (deciduous coniferous trees) were found to be underestimated. The RMSE of the tree height was 0.84 m, and the width of the canopy crown was 1.51 m in test area 1. Further, the RMSE of the tree height was 2.45 m, and the width of the canopy crown was 1.53 m in test area 2. The experiment results validated the use of drone images for the extraction of a tree structure.

• Korean Journal of Plant Taxonomy
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• v.41 no.3
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• pp.223-229
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• 2011

The taxonomy of the Isodon excisus complex has been ambiguous and problematic because the morphological characters, especially characters related to the leaf distinguishing subgroups of the complex in the original descriptions, are variable. To elucidate the taxonomic structure of the I. excisus complex in Korea, 34 characters were measured from 70 OTUs representing different locations and analyzed by principal component analysis (PCA). The analysis showed that principle component axis 1, 2, 3 (PC1, PC2, PC3) represents 52.0% of the total variance and characters showing high loading values for PC1 were leaf shape, density of non-glandular hairs on the lower surface of the leaf, and characters related to the teeth of the leaf. The length of apical tooth and the angle between two widest points of the leaf were highly correlated to PC2 and PC3, respectively. Three-dimensional scatter plotting of OTUs for PC1, PC2, and PC3 axis showed that the areas of previously recognized three subgroups of I. excisus completely overlapped. Our result supported that just one taxon, I. excisus var. excisus, should be recognized in the complex at the variety level.

• Journal of the Korean Geographical Society
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• v.46 no.1
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• pp.81-99
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• 2011

The purpose of this paper is to systemize the spatial studies of logistics industry by arranging the partially scattered current studies on spatial studies of logistics industry overall. Logistics industry now builds a complex spatial organization which has been developed to the stages of independent optimization by materials management and physical distribution providing specialized logistics services, logistics, and supply chain management including IT and management step by step. The complex spatial organization of logistics industry has been systematized with geographical space and virtual space, disintegration and integration, and intermediation and disintermediation. The three areas reported a dynamic characteristic overlapped in space. The dynamic characteristic has a dose relationship with interaction between IT and space of economic activities.

• Human Ecology Research
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• v.54 no.2
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• pp.131-139
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• 2016

This study analyzes the welfare services and spatial composition of social welfare centers that represent complex welfare facilities in order to provide basic information for the spatial planning of social welfare centers. We examined 15 social welfare centers built in the 2000s. A literature review and case study were used as research methodology. The findings are as follow. First, services provided at the surveyed facilities overlapped for seniors and the handicapped. Most social welfare centers provided welfare services for seniors, young children, and teenagers. Second, the proportion of common area, program rooms was high for spatial composition. Third, front access by car was most common (used at nine centers) for the design of the access area and used by. Fourth, shared entry and exit was most common (used at 10 centers) for the design of the entrance. Fifth, regarding space combining style, a mixed style was most frequently used (observed at seven centers) where different private areas for different service users were partly mixed on certain floors. Sixth, a corridor type was most common (used at seven centers) for the design of a corridor space where visitors could walk along the corridor to access individual rooms. Based on the findings, we propose spatial composition of social welfare centers to promote mingling and exchanges among users of different generations.

• Management Science and Financial Engineering
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• v.14 no.1
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• pp.23-34
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• 2008

In this study, we consider stationary waiting times in a Poisson driven single-server m-node queues in series. We assume that service times at nodes are independent, and are either deterministic or non-overlapped. Each node excluding the first node has a finite waiting line and every node is operated under a FIFO service discipline and a communication blocking policy (blocking before service). By applying (max, +)-algebra to a corresponding stochastic event graph, a special case of timed Petri nets, we derive the explicit expressions for stationary waiting times at all areas, which are functions of finite buffer capacities. These expressions allow us to compute the performance measures of interest such as mean, higher moments, or tail probability of waiting time. Moreover, as applications of these results, we introduce optimization problems which determine either the biggest arrival rate or the smallest buffer capacities satisfying probabilistic constraints on waiting times. These results can be also applied to bounds of waiting times in more general systems. Numerical examples are also provided.

• The KIPS Transactions:PartC
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• v.17C no.2
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• pp.165-172
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• 2010

Sensor network can be applied in many areas in our life, and security is very important in applying sensor network. For secure sensor communication, pairwise key establishment between sensor nodes is essential. In this paper, we cluster the network field in hexagonal shapes and preassign three different kinds of key information for each sensor according to its expected location. We adopt overlapped key string pool concept for our clustered network architecture and every node uses the part of sub-strings for setting up pairwise keys with all neighboring nodes in its own cluster and from different clusters according to respective position with small amount of information. Our proposal decreases the memory requirement and increases security level efficiently.

• Journal of Wetlands Research
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• v.21 no.spc
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• pp.80-89
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• 2019

The purpose of this study is to analyze the relationship between SPI (Standardized Precipitation Index) meteorological drought and RDI (Reservoir Drought Index) agricultural drought for Geum river basin. Drought Indices was calculated by collecting data of precipitation and agricultural reservoir water storage rate from 2014 to 2016. To evaluated the correlation between meteorological and agricultural drought, the Pearson correlation and the Receiver Operation Characteristic (ROC) analysis were conducted to evaluate the correlation between meteorological and agricultural droughts. The SPI-6 and RDI showed the highest relationship with Pearson coefficient 0.606 and ROC hit rates 0.722 respectively, and the spatial occurrence patterns of drought using overlapped SPI-6 and RDI, the big differences between the 2 indices were occurred in the upstream areas of Miho stream and Nonsan stream from August to October 2015. The analysis using reservoirs specifications for areas where reservoir droughts occurred was conducted, and the areas showing severe drought of RDI were the reservoir areas having relatively small value of basin magnifying power (BMP). This means that a reservoir has the reaction capability for agricultural drought mainly depending on the reservoir BMP.

• Journal of Broadcast Engineering
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• v.14 no.4
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• pp.518-536
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• 2009

To verify the performance of a Distributed Translator Network(DTxR) system in the real world conditions, 5 legacy DTV broadcasting repeater sites were implemented with 5 DTxR systems and field-tested by the DTV field test truck. The 4 DTV broadcasting repeater sites are selected in congested areas where their service areas are overlapped and the 5th site is deviated from the other sites to examine the effect of long-delayed multipath signals. First of all, we checked the receiving signal of the main station that used as a transmitting signal in 5 DTxR systems on the pre-selected 60 test points and tested every case of a DTxR system's on & off except 1 repeater site due to the already built-in DTV repeater system. The test items are received signal electric field strength, noise margin, ease of reception and subjective evaluation of the picture quality for received signals. We used 3rd, 5th, and 6th generation DTV receivers to examine the differences of the receivability by each generation of DTV receivers. Reviewing the test results, we conclude that the DTxR system can be adopted in the current DTV Repeater sites and it could improve the quality and receivability of the main signals by extending the service areas and enhancing the signal levels in the shadow areas without using the extra broadcasting channels.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1931-1938
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• 2012

This study evaluated whether the installed location of air quality monitoring stations is at an optimal level in an effort to improve the health and environmental quality of the surrounding areas of the Pohang Steel Complex. As a result of analyzing the atmospheric flow field, it was found that the location of air quality monitoring stations was acceptable in case of Daesong-myeon(The 1st Division of Local Wind Sector) and Jukdo-dong(The 3rd Division of Local Wind Sector). However, the air quality monitoring stations installed at Daedo-dong and Jukdo-dong is judged to have made an overlapped measurement because the stations existed at the Division of the same Wind Sector. Accordingly, this study suggests that the further air quality monitoring stations should be additionally installed at Buk-gu areas of Pohang where more than 50% of the population of Pohang is living presently. As a result of the analysis of air contaminant concentration distribution, the Jangheung-dong area showed higher concentration distribution than other areas in case of $PM_{10}$ while the Daesong-myeon area showed a comparatively higher concentration distribution in case of $O_3$. Conclusively, this study indicates that it is high time to prepare an aggressive management of $PM_{10}$ and $O_3$ which causes a harmful impact on the life and health of the residents of the target areas.

• Korean Journal of Plant Resources
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• v.24 no.4
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• pp.370-378
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• 2011

To address infra-specific relationships of Sedum kamtschaticum Fisch., and to provide the fundamental information for developing new horticultural variations, we analyzed the morphology of individuals in four natural populations (Mt. Gwangdeok, Mt. Samyeong, Mt. Yonghwa, Tongyeong) and investigated the vegetations of these area. Based on 50 morphological characters the principle component analysis (PCA) has been performed. Principle component axis 1, 2, and 3 explain 22.9%, 14.2%, and 7.4% of total variations, respectively. Dot plot of OTUs in PC2 by PC1 area showed that the areas of four populations are completely overlapped. The result of PCA and the statistics of each character indicate that all of morphological characters are overlapped in these four populations. The maximum deviations are found in the characters related in the size and shape of the leaf. In the vegetation analyses, eighteen community plots that we investigated were grouped into 10 subcommunities: subcomm. Boehmeria spicata, subcomm. Artemisia stolonifera, subcomm. Artemisia keiskeana, subcomm. Impatiens nolitangere, subcomm. Crepidiastrum chelidoniifolium, subcomm. Urtica thunbergiana, subcomm. Artemisia gmelini, subcomm. Commelina communis, subcomm. Erigeron annuus-Artemisia princeps, and typical subcommunity.