• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.81-86
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• 2020

Ambient backscatter communication has a drawback in which the transmission power is limited because the data is transmitted using the ambient RF signal. In order to improve transmission efficiency between transceiver, a channel estimator capable of estimating channel state at a receiver is needed. In this paper, we consider the K-means algorithm to improve the performance of the channel estimator based on EM algorithm. The simulation uses MSE as a performance parameter to verify the performance of the proposed channel estimator. The initial value setting through K-means shows improved performance compared to the channel estimation method using the general EM algorithm.

• Investigative Magnetic Resonance Imaging
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• v.15 no.2
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• pp.110-122
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• 2011

Purpose : The purpose of this study is to establish the method generating human brain anatomical connectivity from Korean children and evaluating the network topological properties using small-world network analysis. Materials and Methods : Using diffusion tensor images (DTI) and parcellation maps of structural MRIs acquired from twelve healthy Korean children, we generated a brain structural connectivity matrix for individual. We applied one sample t-test to the connectivity maps to derive a representative anatomical connectivity for the group. By spatially normalizing the white matter bundles of participants into a template standard space, we obtained the anatomical brain network model. Network properties including clustering coefficient, characteristic path length, and global/local efficiency were also calculated. Results : We found that the structural connectivity of Korean children group preserves the small-world properties. The anatomical connectivity map obtained in this study showed that children group had higher intra-hemispheric connectivity than inter-hemispheric connectivity. We also observed that the neural connectivity of the group is high between brain stem and motorsensory areas. Conclusion : We suggested a method to examine the anatomical brain network of Korean children group. The proposed method can be used to evaluate the efficiency of anatomical brain networks in people with disease.

• Korean Journal of Ecology and Environment
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• v.38 no.2 s.112
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• pp.137-145
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• 2005

Traditional screening techniques have missed up to 99% of microbial resources existing in the nature. Strategies of direct cloning of environmental DNAs comprising tine genetic blueprints of entire microbial metagenomes provide vastly more genetic information than is contained in the culturable. Therefore, one way to screening the useful gene in a variety of environments is the construction of metagenomic DNA library. In this study, the water samples were collected from Daecheong Reservoir in the mid Korea, and analyzed by T-RFLP to examine the diversity of the microbial communities. The crude DNAs were extracted by SDS-based freezing-thawing method and then further purified using an $UltraClean^{TM}kit$ (MoBio, USA). The metagenomic libraries were constructed with the DNAs partially digested with EcoRI, BamHI, and SacII in Escherichia coli DH10B using the pBACe3.6 vector. About 14.0 Mb of metagenomic libraries were obtained with average inserts 13 ${\sim}$ 15 kb in size. The genes responsible for degradation of 1, 2-dichloroethane (1, 2-DCE) via hydrolytic dehalogenation were identified from the metagenomic libraries by colony hybridization. The 1, 2-dichloroethane dehalogenase gene (dhlA) was cloned and its nucleotide sequence was analyzed. The activity of the 1, 2-DCE dehalogenase was highly expressed to the substrate. These results indicated that the dhlA gene identified from the metagenomes derived from Deacheong Reservoir might be useful to develop a potent strain for degradation of 1, 2-DCE.

• Journal of Korean Home Economics Education Association
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• v.19 no.3
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• pp.133-147
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• 2007

The purpose of this study was to identify the effect on the evaluation of a female teachers' role-performance based on appearance according to the clothing attitude of students and their parents. Based on the results of this study a female teachers' role-performance evaluation can be broken down into four ability areas: leaning guidance, living guidance, human relations, and learning management. Likewise the clothing attitudes of students and their parents can be divided into three groups, the clothing oriented group, the trend-individuality group, and the chastity oriented group. The trend-individuality group of students felt that female teachers' appearances have a significant effect on learning guidance and human relations ability while parents thought that there was little relationship or that it has a moderate effect on the role of learning guidance. Because the concerns of students and parents about female teachers' clothing has an effect on female teachers' role performance evaluation, when directing a student group with a high concern for clothing, female teachers need to be sensitive about their appearances and it's affect on learning guidance, human relations, and class management. Based on these results, students and parents felt that female teachers' appearances have an effect on their role performance according to their clothing attitudes.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.10
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• pp.1055-1064
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• 2006

Extremely slow growing anammox(anaerobic ammonium oxidation) bacteria were cultivated using a combination of UASB(Upflow Anaerobic Sludge Blanket) reactor seeded with anaerobic granular sludge and carbon-fiber cultivating reactor. After 180 days of continuous cultivation, average nitrogen removal rate showed 0.54 kg $N/m^3-day$ when 0.6 kg $N/m^3-day$ of nitrogen loading was applied. The black granule was changed to brown and red granule as continuous operation, and the red granule was highly dependant on the high anammox activity. Microbial community structure of red granule in the UASB reactor was analyzed by molecular methods such as gene cloning, phylogenetic tree analysis, and FISH(Fluorescence In Situ Hybridization) method. As a result of gene cloning and phylogenetic tree analysis, 5 kinds of phylum were found to be Planctomycetes, Proteobacteria, Acidobacteria, Chlorobi and Chloroflexi. 13 clones were matched to anammox bacteria among 51 clones in the red anammox granule. In-silico test which used cloning information and FISH probe of the AMX368 was conducted to detect the presence of anammox bacteria in the red anammox granule. As a result of in-silico test only one clone was exactly matched to AMX368 but 11 clones was mutated one base among 18 bases representing all 12 clones are anammox bacteria. A filamentous Chloroflexi might be related to the granulation of anammox bacteria. As a result of FISH analysis, anammox bacteria was abundant in the red anammox granule.

• The Journal of Bigdata
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• v.5 no.1
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• pp.155-180
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• 2020

It takes the most important role the problem of assigining vehicles and desigining optimal routes for each vehicle in order to enhance the logistics service level. While solving the problem, various cost factors such as number of vehicles, the capacity of vehicles, total travelling distance, should be considered at the same time. Although most of logistics service providers introduced the Transportation Management System (TMS), the system has the limitation which can not consider the practical constraints. In order to make the solution of TMS applicable, it is required experts revised the solution of TMS based on their own experience and intuition. In this research, different from previous research which have focused on minimizing the total cost, it has been proposed the methodology which can enhance the efficiency and fairness of asset utilization, simultaneously. First of all, it has been adopted the Cluster-First Route-Second (CFRS) approach. Based on the location of customers, we have grouped customers as clusters by using four different clustering algorithm such as K-Means, K-Medoids, DBSCAN, Model-based clustering and a procedural approach, Fisher & Jaikumar algorithm. After getting the result of clustering, it has been developed the optiamal vehicle routes within clusters. Based on the result of numerical experiments, it can be said that the propsed approach based on CFRS may guarantee the better performance in terms of total travelling time and distance. At the same time, the variance of travelling distance and number of visiting customers among vehicles, it can be concluded that the proposed approach can guarantee the better performance of assigning tasks in terms of fairness.

• Korean Journal of Environment and Ecology
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• v.32 no.3
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• pp.289-302
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• 2018

The study investigated the forest vegetation in 59 plots between June 2017 and August 2017 to understand the forest vegetation structure of the protected zone for forest genetic resource conservation (forest genetic resource reserve area) in Heuksando Island. We classified the vegetation using the Z-M phytosociological method analyzed the importance value and species diversity of each vegetation classification. The analysis showed the Camellia japonica community group at a top level of forest vegetation hierarchy. In the level of community, it was classified into Dendropanax morbiferus community (Vegetation unit 1; VU 1), Carpinus turczaninowii community, and C. japonica typical community (VU 6). C. turczaninowii community was subdivided into Buxus koreana group (VU 2), Rhododendron mucronulatum group (VU 3), Vitis amurensis group (VU 4) and C. turczaninowii typical group (VU 5). Therefore, it was classified into a total of six vegetation units (one community group, three communities, and four groups). The analysis of the mean codominant value of each VU show that Quercus acuta was the highest in VU 1, C. turczaninowii in VU 2, Pinus thunbergii in VU 3, Pinus densiflora in VU 4, and Castanopsis sieboldii in VU 5 and VU 6. The analysis of species diversity showed that VU 2 was the highest among six units in species richness index, species diversity index, and species evenness index. VU 6 showed the highest among six units in species dominance index. In conclusion, a synecology approach to manage six units and twelve species groups was needed for the forest vegetation of Heuksando Island protected area for forest genetic resource conservation.

• Journal of Internet Computing and Services
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• v.24 no.2
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• pp.67-74
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• 2023

Stock price prediction research in the financial sector aims to ensure trading stability and achieve profit realization. Conventional statistical prediction techniques are not reliable for actual trading decisions due to low prediction accuracy compared to randomly predicted results. Artificial intelligence models improve accuracy by learning data characteristics and fluctuation patterns to make predictions. However, predicting stock prices using long-term time series data remains a challenging problem. This paper proposes a stable and reliable stock price prediction method using K-means clustering-based data augmentation and normalization techniques and LSTM models specialized in time series learning. This enables obtaining more accurate and reliable prediction results and pursuing high profits, as well as contributing to market stability.

• Korean Journal of Agricultural and Forest Meteorology
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• v.20 no.1
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• pp.117-126
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• 2018

The purpose of this study is to analyze the spatial distribution characteristics and spatial changes of Automatic Weather Stations (AWS) in mountainous areas with altitude more than 200 meters in South Korea. In order to analyze the spatial distribution patterns, spatial analysis was performed on 203 Automatic Mountain Meteorology Observation Station (AMOS) points from 2012 to 2016 by Euclidean distance analysis, nearest neighbor index analysis, and Kernel density analysis methods. As a result, change of the average distance between 2012 and 2016 decreased up to 16.4km. The nearest neighbor index was 0.666632 to 0.811237, and the result of Z-score test was -4.372239 to -5.145115(P<0.01). The spatial distributions of AMOSs through Kernel density analysis were analyzed to cover 129,719ha/a station in 2012 and 50,914ha/a station in 2016. The result of a comparison between 2012 and 2016 on the spatial distribution has decreased about 169,399ha per a station for the past 5 years. Therefore it needs to be considered the mountainous regions with low density when selecting the site of AMOS.

• International Journal of Highway Engineering
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• v.1 no.1
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• pp.107-119
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• 1999

The joints in the jointed concrete pavement provide a control against transverse or longitudinal cracking at slab, which may be caused by temperature or moisture variation during or after hydration. Without control of cracking, random cracks cause more serious distresses and result in structural or functional failure of pavement system. However, joints nay cause distresses due to its inherent weakness in structural integrity. Thus, the evaluation at joint is very important. and the joint-related distresses should be evaluated reasonably for economic rehabilitation. The purpose of this paper was to develop an evaluation system at joints of jointed concrete pavement using finite element analysis program, ILLI-SLAB, and nondestructive testing device. FWD. To develop an evaluation system for JCP, a sensitivity analysis was performed using ILLI-SLAB program with a selected variables which might affect fairly to on the performance of transverse joints. The most significant variables were selected from precise analysis. An evaluation charts were made for jointed concrete pavement by adopting the field FWD data. It was concluded that the variables which most significantly affect to pavement deflections are the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G), and limiting criteria on the performance of joints at JCP are 300pci. 500,000 lb/in. respectively. Using these variables and FWD test, a charts of load transfer ratio versus surface deflection at joints were made in order to evaluate the performance of JCP. Practically, Chungbu highway was evaluated by these evaluation charts and FWD field data for jointed concrete pavement. For Chungbu highway, only one joint showed smaller value than limiting criterion of the modulus of dowel/concrete interaction(G). The rest joints showed larger values than limiting criteria of the modulus of subgrade reaction(K) and the modulus of dowel/concrete interaction(G).