• Journal of the Korea Society of Computer and Information
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• v.15 no.12
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• pp.227-235
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• 2010

This paper proposes the recommendation system which is advanced using RFM method and Association Rules in e-Commerce. Using a implicit method which is not used user's profile for rating, it is necessary for user to keep the RFM score and Association Rules about users and items based on the whole purchased data in order to recommend the items. This proposing system is possible to advance recommendation system using RFM method and Association Rules for cross-selling, and also this system can avoid the duplicated recommendation by the cross comparison with having recommended items before. And also, it's efficient for them to build the strategy for marketing and crm(customer relationship management). It can be improved and evaluated according to the criteria of logicality through the experiment with dataset collected in a cosmetic cyber shopping mall. Finally, it is able to realize the personalized recommendation system for one to one web marketing in e-Commerce.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.1C
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• pp.8-16
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• 2010

This paper presents a new small target detection method using the cross product of the temporal pixels based on the temporal profile in infrared (IR) image sequences. The temporal characteristics of small targets and the various backgrounds are different. A new algorithm classifies target pixels and the background pixels through the hypothesis testing using the cross product of pixels on the temporal profile and predicts the temporal backgrounds based on the results. The small targets are detected by subtracting the predicted temporal background profile from the original temporal profile. For the performance comparison between the proposed algorithm and the conventional algorithms, the receiver operating characteristics (ROC) curves is computed in experiment. Experimental results show that the proposed algorithm has better discrimination and a lower false alarm rate than the conventional methods.

• Journal of Microbiology and Biotechnology
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• v.24 no.3
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• pp.386-393
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• 2014

Possible cross-transmission of hospital-associated enterococci between human patients, medical staff, and hospital environments has been extensively studied. However, limited information is available for veterinary hospital-associated Enterococcus isolates. This study investigated the possibility of cross-transmission of antibiotic-resistant enterococci between dog patients, their owners, veterinary staff, and hospital environments. Swab samples (n=465) were obtained from five veterinary hospitals in Seoul, Korea, during 2011. Forty-three Enterococcus strains were isolated, representing seven enterococcal species. E. faecalis and E. faecium were the most dominant species (16 isolates each, 37.2%). Although slight differences in the antibiotic resistance profiles were observed between the phenotypic and the genotypic data, our antibiogram analysis demonstrated high prevalence of the multiple drug-resistant (MDR) isolates of E. faecalis (10/16 isolates, 62.5%) and E. faecium (12/16 isolates, 75.0%). Pulsed-field gel electrophoretic comparison of the MDR isolates revealed three different clonal sets of E. faecalis and a single set of E. faecium, which were isolated from different sample groups or dog patients at the same or two separate veterinary hospitals. These results imply a strong possibility of cross-transmission of the antibiotic-resistant enterococcal species between animal patients, owners, veterinary staff, and hospital environments.

• Journal of Korea Water Resources Association
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• v.53 no.12
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• pp.1097-1107
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• 2020

A methodology has been proposed to understand the spatiotemporal changes of the river topography through the longitudinal change of the geometric characteristics of the cross-sections and the properties related thereto. Three-dimensional spatial information of the riverbed was obtained through the detailed bathymetry survey using an acoustic echo sounder for the reach from Gumi Weir to Chilgok Weir in the Nakdong river. Geometric informations for the reference sections were extracted using the acquired bathymetry survey data. By comparing the geometric properties for the reference sections, it was possible to catch the topographic characteristics and its changes over a reach of the channel. Through comparison with past survey data, it was also possible to quantitatively grasp the amount of change in cross-sectional area and volumetric change of riverbed. It is expected that a quantitative evaluation of river topography changes will be possible by applying the method proposed in this study.

• Wind and Structures
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• v.35 no.4
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• pp.269-285
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• 2022

The pressure-mitigating effects of a high-speed train passing through a tunnel with a partially reduced cross-section are investigated via the numerical approach. A compressible, three-dimensional RNG k-ε turbulence model and a hybrid mesh strategy are adopted to reproduce that event, which is validated by the moving model test. Three step-like tunnel forms and two additional transitions at the tunnel junction are proposed and their aerodynamic performance is compared and scrutinized with a constant cross-sectional tunnel as the benchmark. The results show that the tunnel step is unrelated to the pressure mitigation effects since the case of a double-step tunnel has no advantage in comparison to a single-step tunnel, but the excavated volume is an essential matter. The pressure peaks are reduced at different levels along with the increase of the excavated earth volume and the peaks are either fitted with power or logarithmic function relationships. In addition, the Arc and Oblique-transitions have very limited gaps, and their pressure curves are identical to each other, whereas the Rec-transition leads to relatively lower pressure peaks in C_Pmax, C_Pmin, and ΔC_P, with 5.2%, 4.0%, and 4.1% relieved compared with Oblique-transition. This study could provide guidance for the design of the novel railway tunnel.

• The Journal of the Acoustical Society of Korea
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• v.28 no.4
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• pp.401-407
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• 2009

In this paper, we propose a novel method for the cross-correlation based double-talk detection (DTD), which employing the Gaussian Mixture Model (GMM) in the frequency domain. The proposed algorithm transforms the cross correlation coefficient used in the time domain into 16 channels in the frequency domain using the discrete fourier transform (DFT). The channels are then selected into seven feature vectors for GMM and we identify three different regions such as far-end, double-talk and near-end speech using the likelihood comparison based on those feature vectors. The presented DTD algorithm detects efficiently the double-talk regions without Voice Activity Detector which has been used in conventional cross correlation based double-talk detection. The performance of the proposed algorithm is evaluated under various conditions and yields better results compared with the conventional schemes. especially, show the robustness against detection errors resulting from the background noises or echo path change which one of the key issues in practical DTD.

• Wind and Structures
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• v.5 no.2_3_4
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• pp.227-244
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• 2002

Recently, the prediction of wind environment around a building using Computational Fluid Dynamics (CFD) technique comes to be carried out at the practical design stage. However, there have been very few studies which examined the accuracy of CFD prediction of flow around a high-rise building including the velocity distribution at pedestrian level. The working group for CFD prediction of wind environment around building, which consists of researchers from several universities and private companies, was organized in the Architectural Institute of Japan (AIJ) considering such a background. At the first stage of the project, the working group planned to carry out the cross comparison of CFD results of flow around a high rise building by various numerical methods, in order to clarify the major factors which affect prediction accuracy. This paper presents the results of this comparison.

• Journal of Labour Economics
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• v.41 no.3
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• pp.129-159
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• 2018

The foremost aim of the paper is to evaluate the flexibility and stability of the Korean labor market through a cross-country comparison with OECD countries. Evaluating by the OECD Employment Protection Legislation Index, the flexibility of permanent job layoff in Korea is close to the average of OECD countries. Employment of temporary workers appears to be relatively flexible allowing for effective indicators such as the proportion of temporary workers among paid employees. As regards security, the levels of job security, income security and combination security are all far below the OECD average. A panel data analysis of OECD countries reveals that labor productivity increases as regulations on permanent job layoff become looser and regulations on temporary employment become more rigorous.

• Structural Engineering and Mechanics
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• v.32 no.6
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• pp.705-724
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• 2009

The two major widely used building design code documents of reinforced concrete structures are the ACI 318-05 and Eurocode for the Design of Concrete Structures EC2. Therefore, a thorough comparative analysis of the provisions of these codes is required to confirm their validity and identify discrepancies in either code. In this context, provisions of flexural computations would be particularly attractive for detailed comparison. The provisions of safety concepts, design assumptions, cross-sectional moment capacity, ductility, minimum and maximum reinforcement ratios, and load safety factors of both the ACI 318-05 and EC2 is conducted with parametric analysis. In order to conduct the comparison successfully, the parameters and procedures of EC2 were reformatted and defined in terms of those of ACI 318-05. This paper concluded that although the adopted rationale and methodology of computing the design strength is significantly different between the two codes, the overall EC2 flexural provisions are slightly more conservative with a little of practical difference than those of ACI 318-05. In addition, for the limit of maximum reinforcement ratio, EC2 assures higher sectional ductility than ACI 318-05. Overall, EC2 provisions provide a higher safety factor than those of ACI 318-05 for low values of Live/Dead load ratios. As the ratio increases the difference between the two codes decreases and becomes almost negligible for ratios higher than 4.

• Coupled systems mechanics
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• v.1 no.3
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• pp.285-295
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• 2012

In this paper, two types of porous burners with radial and axial flow have been modeled numerically and compared. For this purpose, governing equations were solved one-dimensionally for methane-air premix gas. The mechanism used in simulating combustion phenomenon was 15 stage reduced mechanism based on GRI3.0. In order to compare the two burners, the inlet flow rate and fuel-air ratio have been assumed equal for the two burners. The results of the study indicated that reduction in speed and increase in cross-section area in the direction of flow have a considerable influence on the behavior of radial burner in comparison to axial burner. Regarding temperature distribution inside the burner, it was observed that the two above mentioned factors can be influential in temperature of flame propagation region. Also, regarding distribution of CO and NO emission, the results indicate that the porous radial burner has lower emissions in comparison to the axial once. The output radiative heat transfer efficiency of the two burners was also compared and in this case also even the radial porous burner was found to be preferable.