• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.10
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• pp.1528-1534
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• 2001

In order to improve Leak-Be(ore-Break methodology, more precisely the crack growth evaluation, a round robin analysis was proposed by the CEA Saclay. The aim of this analysis was to evaluate the crack initiation life, penetration life and shape of through wall crack under cyclic bending loads. The proposed round robin analysis is composed of three main topic; fatigue crack initiation, crack propagation and crack penetration. This paper deals with the first topic, crack initiation in a notched pipe under four point bending. Both elastic-plastic finite element analysis and Neuber's rule were used to estimate the crack initiation life and the finite element models were verified by mesh-refinement, stress distribution and global deflection. In elastic-plastic finite element analysis, crack initiation life was determined by strain amplitude at the notch tip and strain-life curve of the material. In the analytical method, Neuber's rule with the consideration of load history and mean stress effect, was used for the life estimation. The effect of notch tip radius, strain range, cyclic hardening rule were examined in this study. When these results were compared with the experimental ones, the global deformation was a good agreement but the crack initiation cycle was higher than the experimental result.

• Journal of Korea Water Resources Association
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• v.46 no.3
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• pp.287-299
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• 2013

The objective of this study is to derive and evaluate the drought threshold level based on hydro-meteorological data using historical drought events. After collecting the drought events during 1991 to 2009 year, the observed meteorological data and estimated hydrological component from LSM are used as input for the percentile analysis that is drought analysis data. The drought threshold level that precipitation and runoff of 3 month duration are less than 35%, soil moisture of 2 month duration is less than 35% and evapotranspiration of 3 month duration is more than 65% is derived using ROC analysis that are objective test method. ROC analysis with SPI (3) is performed to evaluate the applicability of threshold level in the domestic. As a result, it can be concluded that the derived drought threshold level show better performance to reflect the historical drought events than SPI (3) and it reasonably explain the spatial drought situation through the spatial analysis.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.11
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• pp.1131-1137
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• 2017

Recently, regulations on fuel efficiency and $CO_2$ emissions have been reinforced in automobile industries. As a result, many companies make an effort to satisfy these regulations by adapting composite materials to the automobile body as well as its components. In particular, the lower control arm in the suspension system is subjected to heavy loads and is designed to be thick to meet operating loads. Therefore, it is essential for the lower control arm to reduce weight and to secure the durability assessment. In this paper, we conducted structural analysis by performing stress and stiffness analysis under given load conditions through finite element analysis, and verified whether it satisfies the load and stiffness conditions. The inertia relief method is adapted to the process of analysis, and the principal stress is used as a criterion for evaluation. Based on these results, the durability assessment is carried out using the stress-life method.

• Journal of Food Hygiene and Safety
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• v.28 no.3
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• pp.222-226
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• 2013

A simple and sensitive analytical method was developed using gas chromatograph with electron capture detector (GC-ECD) and gas chromatograph-mass spectrometer (GC-MS) for determination and identification of chloropicrin. Because of small molecular weight and high volatile properties of chloropicrin, analytical method was developed utilizing headspace extraction and direct injection to the GC. The developed method was validated using hulled rice sample spiked with chloropicrin at different concentration levels, 0.1 and 0.5 mg/kg. Average recoveries of chloropicrin (using each concentration three replicates) ranged 77.7~79.3% with relative standard deviations less than 10% and calibration solutions concentration in the range $0.005{\sim}0.5{\mu}g/mL$, and limit of detection (LOD) and limit of quantification (LOQ) were 0.004 and 0.01 mg/kg, respectively. The result showed that developed analytical methods was successfully applied to detect a small amount of chloropicrin in hulled rice.

• Journal of the Korean Society for Library and Information Science
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• v.55 no.1
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• pp.107-133
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• 2021

This study was performed in order to provide suggestions on how to strengthen librarian competency by evaluating and analyzing the competency value of librarians as information professions. First, the study divided the common competency value of librarians as human capital of libraries into skills, knowledge, behavior and attitude, and analyzed each area of competency value for librarians of the A-library. As a result, the average of the 'librarian's behavior and attitude' area was the highest, followed by the 'librarian's skill' area and the 'librarian's knowledge' area. Second, in terms of 'librarian's skill', A-library librarians' competence values were high in the order of 'communication', 'leadership', 'technology' and in the terms of 'librarian's knowledge' ones were high in the order of 'law and policy', 'marketing', 'learning and growth' and 'finance and accounting'. In addition, in areas of 'librarian's behavior and attitude', the factors were high in the order of 'ethics and values', 'interpersonal relationships' and 'customer service'. Third, the analysis of whether the average difference exists depending on the characteristics of A-library librarians on their evaluation of the competency value shows that only the 'working period' factor in the total competency value and the two factors 'age' and 'working period' were statistically significant in the 'librarian's knowledge' area. Forth, as a result of a regression analysis to identify the characteristics of A-library librarians and their impact on competency value, only the 'final education' factor was statistically significant for the competency value of the 'librarian's skill' area. Fifth, in the survey on problems and desirable improvement measures in increasing the competency value of librarians, the proportion of presenting problems and improvement plan in systemic aspects such as the 'librarian qualification system' and 'librarian training system' was high.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.1
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• pp.97-108
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• 2018

The purpose of this study is to propose the construction of a visibility analysis model, which is the basis of the analysis for landscape management on the heritage sites such as historic villages and scenic sites. Results of the visibility analysis using DEM and the visibility analysis of DSM based on 3D mapping data are compared as follows: Precision level of the extracted data was confirmed to be less than 6.5cm, based on RTK survey results produced by constructing orthoimage data and DSM from the digital data of 2cm-class GSD(Ground Sample Distance) obtained by using a small UAV(Unmanned Aerial Vehicle). As a result of comparing the visibility analysis data of Digital Surface Model (DSM) using a small UAV with Digital Elevation Model(DEM) applying the height of the building to the Digital Topographic Map, it was confirmed that more realistic visibility analysis can be accomplished by applying DSM, as the structures such as fences, trees, and houses are reflected in the topographic data. The visibility analysis model using the 3D mapping technique can efficiently obtain the constantly changing topographic information when needed, by immediately constructing the data by utilizing a small UAV. It seems to be possible to propose a reasonable analysis result for preservation management such as landscape evaluation of cultural property.

• Journal of Climate Change Research
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• v.9 no.1
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• pp.13-29
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• 2018

This study presented evaluation procedure for selecting appropriate GCMs and downscaling method by focusing on the climate extreme indices suitable for climate change adaptation. The procedure includes six stages of processes as follows: 1) exclusion of unsuitable GCM through raw GCM analysis before bias correction; 2) calculation of the climate extreme indices and selection of downscaling method by evaluating reproducibility for the past and distortion rate for the future period; 3) selection of downscaling method based on evaluation of reproducibility of spatial correlation among weather stations; and 4) MME calculation using weight factors and evaluation of uncertainty range depending on number of GCMs. The presented procedure was applied to 60 weather stations where there are observed data for the past 30 year period on Korea Peninsula. First, 22 GCMs were selected through the evaluation of the spatio-temporal reproducibility of 29 GCMs. Between Simple Quantile Mapping (SQM) and Spatial Disaggregation Quantile Delta Mapping (SDQDM) methods, SQM was selected based on the reproducibility of 27 climate extreme indices for the past and reproducibility evaluation of spatial correlation in precipitation and temperature. Total precipitation (prcptot) and annual 1-day maximum precipitation (rx1day), which is respectively related to water supply and floods, were selected and MME-based future projections were estimated for near-future (2010-2039), the mid-future (2040-2069), and the far-future (2070-2099) based on the weight factors by GCM. The prcptot and rx1day increased as time goes farther from the near-future to the far-future and RCP 8.5 showed a higher rate of increase in both indices compared to RCP 4.5 scenario. It was also found that use of 20 GCM out of 22 explains 80% of the overall variation in all combinations of RCP scenarios and future periods. The result of this study is an example of an application in Korea Peninsula and APCC Integrated Modeling Solution (AIMS) can be utilized in various areas and fields if users want to apply the proposed procedure directly to a target area.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.6
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• pp.401-412
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• 2016

On Tuesday, January 17, 1995, an earthquake of magnitude 7.2 struck the Port of Kobe. In effect, the port was practically destroyed. After a hazard investigation, researchers reached a consensus to adopt a performance-based design in port and harbor structures in Japan. A residual displacement of geotechnical structures after an earthquake is one of the most important engineering demands in performance-based earthquake-resistant design. Thus, it is essential to provide reliable responses of geotechnical structures after an earthquake through various techniques. Today, a nonlinear explicit response history analysis(NERHA) of geotechnical structures is the most efficient way to achieve this goal. However, verification of the effective stress analysis, including post liquefaction behavior, is difficult to perform at a laboratory scale. This study aims to rigorously verify the NERHA by using well-defined field measurements, existing numerical tools, and constitutive models. The man-made, Port Island, in Kobe provides intensive hazard investigation data, strong motion records of 1995 Kobe earthquake, and sufficient engineering parameters of the soil. Two dimensional numerical analysis was conducted on the caisson quay wall section at Port Island subjected to the 1995 Kobe earthquake. The analysis result matches very well with the hazard investigation data. The NERHA procedure presented in this paper can be used in further studies to explain and examine the effects of other factors on the seismic behavior of gravity quay walls in liquefiable soil areas.

• The Journal of the Korea Contents Association
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• v.21 no.10
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• pp.67-77
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• 2021

This study conducted topic modeling, association analysis, and sentiment analysis focused on text mining in order to reflect regional characteristics in the process of establishing an information plan in Chungcheongbuk-do. As a result of the analysis, it was confirmed that Chungcheongbuk-do occupies a relatively high proportion of educational activities to bridge the information gap, and is interested in improving infrastructure to provide non-face-to-face, untouched administrative services, and bridge the gap between urban and rural areas. In addition, it is necessary to refer to the fact that there is a positive evaluation of the combination of bio and IT in the regional strategic industry and examples of ICT innovation services. It has been confirmed that smart cities have high expectations for the establishment of various cooperation systems with IT companies, but continuous crisis management is necessary so that they are not related to political issues. It is hoped that the results of this study can be used as one of the methods to specifically reflect regional changes in the process of informatization.

• Journal of Distribution Science
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• v.18 no.3
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• pp.77-85
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• 2020

Purpose: This study examined marketing value as online word-of-mouth media in the foodservice industry, and it did research on online word-of-mouth (e-WOM) communication marketing schemes using mass communication in the industry. The study is also intended to investigate the impact of electronic word-of-mouth (e-WOM) information and communication on product awareness risks, benefits, and word-of-mouth (WOM) impacts on restaurant consumers. Research design, data, and methodology: The analysis was conducted on a valid questionnaire of 425 menu product consumers. The survey was conducted for two months in March 2019. The collected data was analyzed using SPSS and hierarchical regression analysis was applied. Results: It did empirical research on the reciprocal casual relations to online and the existing word-of-mouth communication that have to be preceded to understand characteristics of online word-of-mouth communication for the purpose of this study. The result is summarized as follows. First, the online word-of-mouth (e-WOM) effect on product recognition risk shows the statistically significant effect of information sender characteristics, information recipient characteristics, and online word-of-mouth (e-WOM) communication on product recognition risk. Second, the influence of online word-of-mouth (e-WOM) on product risk benefits shows that the information sender characteristics, the information receiver characteristics, and online communications have a statistically significant effect on product risk benefits. Third, online word of mouth risk recognition had a statistically significant effect on word of mouth acceptance. Fourth, online risk benefit had a statistically significant positive effect on word of mouth (WOM) effect. Conclusions: The communication between online word of mouth (e-WOM) sender and recipient had a positive influence on the product evaluation and attitude change in the foodservice industry, and the word-of-mouth (WOM) effect affected financial and non-financial performance. The results mentioned above indicated that the communication between the sender of the information and the receiver of the information had a positive effect on the product evaluation and attitude change of the menu consumer, and the word-of-mouth (WOM) result affected the financial. Therefore, the online word-of-mouth (e-WOM) effect has a positive effect on the word-of-mouth (WOM) effect of menu products when performed simultaneously and positively between the information sender and the information receiver.