• Journal of the Korean Geographical Society
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• v.33 no.2
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• pp.325-338
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• 1998

본 연구에서는 시.공 복합적인 선형 점 자료를 대상으로 시간과 공간을 함께 고려했을 때 자료 내에 군집(cluster)-시.공 복합 군집(space-time cluster)-이 존재하는 가를 검증하는 방법에 대해 논의하고, 실제 교통사고지점의 분포자료를 분석하여 군집의 유무를 통계적으로 검증하였다. 통계 분석의 결과 다음과 같은 사실이 확인되었다. 첫째, Knox의 분할표 방법과 Mantel의 역수 변환을 이용한 일반화된 회귀분석방법 모두 임계 거리 및 임계 시간 간격의 선택이 분석결과에 영향을 미친다. 둘째, 이러한 임의성을 극복하기 위해 다양한 임계 거리 및 임계 시간 간격(혹은 부가 상수)에 대해 반복 실험한 결과, 일부 임계값의 조합에서 시간과 공간이 서로 독립적이라는 귀무가설을 기각할 수 있는 증거가 발견되었다. 셋째, 시.공 복합 군집의 파악에 가장 적합한 임계 거리와 임계 시간 간격은 공간적으로는 7000m, 시간적으로는 14일 혹은 21일이다. 마지막으로, 통계 분석과정에서 자료에 존재하는 중복 기록 사고들의 존재가 밝혀짐으로써 시.공 복합군집 검증이 탐험적 자료 분석(exploratory data analysis)의 도구로서 가지는 가치를 확인할 수 있었다.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.191-197
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• 2009

In order to characterize the ecological traits of Q. mongolica, we treated the seedlings of this species with three environmental factors, light, moisture and nutrient gradients from March to October 2007, and measured morphological and ecological 17 characters. Lastly calculated ecological niche breadth and niche overlap between Q. mongolica-Q. acutissima and Q. mongolica-Q. variabilis, and analysed them with a special reference to ecological distribution pattern and their competition relationship in Korea. The ecological niche breadth of Q. mongolica showed the lowest in nutrient treatment, but the highest in soil moisture treatment. The ecological niche value under light was intermediate. On comparison of the ecological niche breadth of three oak species, Q. mongolica showed the highest in light environment, which might be a reason for the dominant distribution in the forest plant community, Korea. The ecological niche overlap of Q. mongolica-Q. acutissima and Q. mongolica-Q. varabilis was the widest in moisture treatment, but the narrowest in nutrient treatment and the intermediate in light one. These results means that these three oak species be most competitive in moisture environment than light or nutrient one, and that there are least differentiated among oak species for soil moisture condition. Cluster and PCA ordination showed that Q. mongolica and Q. acutissima were more closely arranged than Q. mongolica and Q. variabilis. From these results, it can be explained that Q. mongolica have more similar ecological niche with Q. acutissima than with Q. variabilis, consequently competition between Q. mongolica and Q. acutissima is intensive than Q. mongolica and Q. variabilis for environment condition, especially in soil moisture.

• Weed & Turfgrass Science
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• v.4 no.2
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• pp.124-128
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• 2015

Large patch, caused by Rhizoctonia solani AG2-2 IV, is a soil-born disease that is the most important of warm season turfgrass such as zoysia and Bermuda grass. This study was conducted to analysis of the soil microbial community structure on large patch. Center of the large patch (CLC), edge (CLE) and healthy (CLH) part of microbial communities were examined using metagenomics in Phylum level. Distribution trends of the rhizosphere microorganisms were similar to the order Proteobacteria, Acidobacteria, Chloroflexi, Firmicutes, Planctomycetes, Gemmatimonadetes, Nitrospira, Cyanobactria and Verrucomicrobia in soil collections. Contrastively Actinobacteria was more 56% abundant in healthy part soil (16%) than in the center (9.28%) or edge (10.84%) parts. Taxonomic distributions were compared among the CLC, CLE and CLH, total 6,948 OTUs were detected in the CLC, 6,505 OTUs for the CLE and 5,537 OTUs were detected in the CLE. Distributions of Actinobacteria OTUs were appeared 615 OTUs in the CLC, 709 OTUs in the CLE and 891 OTUs in the CLH. Among Actinobacteria, 382 OTUs were overlapped in the all soils. Not matched OTUs of CLH (286 OTUs) was detected 23 times higher than CLC (91 OTUs) and CLE (126 OTUs).

• KIPS Transactions on Computer and Communication Systems
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• v.9 no.3
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• pp.45-58
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• 2020

In the current trend of increasing network traffic due to the popularization of cloud service and mobile devices, WAN bandwidth is very low compared to LAN bandwidth. In a WAN environment, a WAN optimizer is needed to overcome performance problems caused by transmission protocol, packet loss, and network bandwidth limitations. In this paper, we analyze the data deduplication algorithm of WANProxy, an open source WAN optimizer, and evaluate its performance in terms of network latency and WAN bandwidth. Also, we evaluate the performance of the two-stage compression method of WANProxy and Zstandard. We propose a new method to improve the performance of WANProxy by revising its data deduplication algorithm and evaluate its performance improvement. We perform experiments using 12 data files of Silesia with a data segment size of 2048 bytes. Experimental results show that the average compression rate by WANProxy is 150.6, and the average network latency reduction rates by WANProxy are 95.2% for a 10 Mbps WAN environment and 60.7% for a 100 Mbps WAN environment, respectively. Compared with WANProxy, the two-stage compression of WANProxy and Zstandard increases the average compression rate by 33%. However, it increases the average network latency by 2.1% for a 10 Mbps WAN environment and 5.27% for a 100 Mbps WAN environment, respectively. Compared with WANProxy, our proposed method increases the average compression rate by 34.8% and reduces the average network latency by 13.8% for a 10 Mbps WAN and 12.9% for a 100 Mbps WAN, respectively. Performance analysis results of WANProxy show that its performance improvement in terms of network latency and WAN bandwidth is excellent in a 10Mbps or less WAN environment while superior in a 100 Mbps WAN environment.

• Korean Journal of Construction Engineering and Management
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• v.19 no.5
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• pp.3-9
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• 2018

Although Life Cycle Cost (LCC) must be evaluated by experts, sometimes it may not allow a sufficient time for even the experienced LCC expert to make rational decisions. Therefore, it often ends with relatively comparing the final numbers. We have broken down 110 technical proposals that are actually bade and accepted for large construction projects, and then have analyzed the uncertainty of Maintenance and Energy (M&E) cost during building life cycle, which turns out be the most volatile factor in uncertainty of LCC. Also we suggest "Value Engineering Index (VEI)" - the reduced M&E cost that is normalized by the reduced first cost. It is analyzed that the most uncertain factors of the M&E cost include repair and replacement term differing from each project, duplicated repair and replacement, non-standard repair items, and site-specific energy cost. Eventually we propose a VEI population with a mean of 1.38 and a standard deviation of 1.19, which is obtained by individually and exclusively applying the uncertain factors of the M&E cost to the 35 standard sample of technical proposals. The LCC evaluators may be able to use the VEI population as the benchmark to select the technical proposal with the most reasonable LCC among many others in two suggested manners; the one is to deterministically calculate the probability of single VEIs, and the other is to stochastically calculate the probability of the VEIs where uncertainty is quantified.

• Journal of The Korean Association For Science Education
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• v.26 no.7
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• pp.775-789
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• 2006

The purpose of this study was to analyze the relevance of the school science contents that have been implemented for the 7-10th grade students in Korea since 2001. To fulfill the purpose of the study, we 1) analyzed the 7th national science curriculum of Korea, California science standards, the national science curriculum of England, Japanese national science curriculum, and current Korean and Japanese science textbooks, 2) conducted a nationwide survey in order to gather opinions from students, teachers, and science specialists. The main findings of this research were as follows: First, the number of topics presented at each grade level should be reduced and similar topics and themes should be integrated for students' deeper understanding. Second, science contents were excessive compared to the allotted teaching time and to foreign countries. Thus, the excessive overlapping and repetition of science contents should be avoided among the primary, middle and high school level, and the number of science concepts and activities should be reduced to an appropriate level considering time allotment for science classes, teachers' workload, laboratory conditions, etc. Third, to cope with the decreasing students' understanding and interests in science as school level and school year goes up, the science curriculum and textbooks should be developed to allow for student to learn science concepts by solving problems confronted in their daily lives. Fourth, a differentiated curriculum such as in-depth and supplementary course should be described not in science contents, but in teaching and learning strategy.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.1
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• pp.163-181
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• 2012

We investigated how useful video tags were in summarizing video speech and how valuable positional information was for speech summarization. Furthermore, we examined the similarity among sentences selected for a speech summary to reduce its redundancy. Based on such analysis results, we then designed and evaluated a method for automatically summarizing speech transcripts using a modified Maximum Marginal Relevance model. This model did not only reduce redundancy but it also enabled the use of social tags, title words, and sentence positional information. Finally, we compared the proposed method to the Extractor system in which key sentences of a video speech were chosen using the frequency and location information of speech content words. Results showed that the precision and recall rates of the proposed method were higher than those of the Extractor system, although there was no significant difference in the recall rates.

• Journal of Advanced Navigation Technology
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• v.19 no.6
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• pp.507-514
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• 2015

The Spatial information research institute of the LX Korea land and geospatial informatix corporation manages infrastructure for the LX global navigation satellite system (GNSS), which comprises 30 monitoring stations nationwide. Since 2014, it has conducted network real-time kinematic (RTK) tests using the master-auxiliary concept (MAC). This study introduces the infrastructure of LX GNSS and presents the results of a performance analysis of the LX RTK service. The analysis was based on a total of 25 cadastral topographic control points in Jeonju, Seoul, and Incheon. For each point, performance was measured over one observation, two repeated observations, and five repeated observations. The measurements obtained from LX MAC and the VRS of the National Geographic Information Institute were compared with the announced coordinates derived from cadastral topographic control points. As a result, the two systems were found to have similar performance with average error and standard deviation differing only by 1 to 2 cm.

• Korean Journal of Ichthyology
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• v.24 no.4
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• pp.272-277
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• 2012

The feeding habits of black scraper, Thamnaconus modestus, were studied using 172 specimens collected in the coastal waters of Geomun-do, Korea. The size of the specimens ranged from 16.2 to 39.1 cm in standard length (SL). T. modestus was a omnivore that consumes mainly benthos. Of the benthos species nephtheidae was the most preferred prey. Its diet also includes, algae, thoracica, gastropoda, desmospongia. Small and medium size individuals (<21~33 cm, SL) fed mainly on nephtheidae and algae. Larger individuals (>33 cm, SL) fed mainly on thoracica. The proportion of nephtheidae decreased as body size increased (>33 cm, SL), whereas the consumption of thoracica gradually increased.

• The KIPS Transactions:PartA
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• v.16A no.1
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• pp.9-16
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• 2009

Because Grid system consists of heterogenous computing resources, which are distributed on a wide scale, it is impossible to efficiently execute applications with scheduling algorithms of a conventional parallel system that, in contrast, aim at homogeneous and controllable resources. To suggest an algorithm that can fully reflect the characteristics of a grid system, our research is focused on examining the type of information used in current scheduling algorithms and consequently, deriving factors that could develop algorithms further. The results from the analysis of these algorithms not only show that static information of resources such as capacity or the number of processors can facilitate the scheduling algorithms but also verified a decrease in efficiency in case of utilizing real time load information of resources due to the intrinsic characteristics of a grid system relatively long computing time, and the need for the means to evade unfeasible resources or ones with slow processing time. In this paper, we propose a new algorithm, which is revised to reflect static information in the logic of WQR(Workqueue Replication) algorithms and show that it provides better performance than the one used in the existing method through simulation.