• The Journal of Information Systems
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• v.30 no.1
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• pp.151-177
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• 2021

Purpose This paper aims to improve management performance by effectively responding to production needs and reducing inventory through synchronizing production planning and procurement in the aviation industry. In this study, the differences in production planning and execution were first analyzed in terms of demand, supply, inventory, and process using the big data collected from a domestic aircraft manufacturers. This paper analyzed the problems in procurement and inventory management using legacy big data from ERP system in the company. Based on the analysis, we performed a simulation to derive an efficient procurement and inventory management plan. Through analysis and simulation of operational data, we were able to discover procurement and inventory policies to effectively respond to production needs. Design/methodology/approach This is an empirical study to analyze the cause of decrease in inventory turnover and increase in inventory cost due to dis-synchronize between production requirements and procurement. The actual operation data, a total of 21,306,611 transaction data which are 18 months data from January 2019 to June 2020, were extracted from the ERP system. All them are such as basic information on materials, material consumption and movement history, inventory/receipt/shipment status, and production orders. To perform data analysis, it went through three steps. At first, we identified the current states and problems of production process to grasp the situation of what happened, and secondly, analyzed the data to identify expected problems through cross-link analysis between transactions, and finally, defined what to do. Many analysis techniques such as correlation analysis, moving average analysis, and linear regression analysis were applied to predict the status of inventory. A simulation was performed to analyze the appropriate inventory level according to the control of fluctuations in the production planing. In the simulation, we tested four alternatives how to coordinate the synchronization between the procurement plan and the production plan. All the alternatives give us more plausible results than actual operation in the past. Findings Based on the big data extracted from the ERP system, the relationship between the level of delivery and the distribution of fluctuations was analyzed in terms of demand, supply, inventory, and process. As a result of analyzing the inventory turnover rate, the root cause of the inventory increase were identified. In addition, based on the data on delivery and receipt performance, it was possible to accurately analyze how much gap occurs between supply and demand, and to figure out how much this affects the inventory level. Moreover, we were able to obtain the more predictable and insightful results through simulation that organizational performance such as inventory cost and lead time can be improved by synchronizing the production planning and purchase procurement with supply and demand information. The results of big data analysis and simulation gave us more insights in production planning, procurement, and inventory management for smart manufacturing and performance improvement.

• Journal of Korea Entertainment Industry Association
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• v.14 no.7
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• pp.79-94
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• 2020

The purpose of this study is to analyze the difference in the effect of presence for the activation of virtual reality sports on participation satisfaction, to suggest continuous screen golf exercise participation, and to provide empirical and academic data for the development of the entire virtual reality sports market. To achieve this purpose, the survey period was from March 13 to May 13, 2020, with five researchers and assistants. The purpose of this study and the questionnaire were fully explained to consumers who experienced screen golf directly, and 247 questionnaires were used as the final valid sample by making a questionnaire with self-administration method. The data processing method was the statistical program Windows SPSS 18.0. First, factor analysis and reliability analysis, second, frequency analysis mean(M) and standard deviation(SD), third, Scheffe analysis among t-test and One-way ANOVA analysis, fourth, correlation analysis between variables and multiple regression analysis were conducted. The results of this study through these methods and procedures are as follows. First, there was a significant difference in participation satisfaction of presence in gender, and participation period of general characteristics. Second, there was a high difference in social presence, social self-reliance, and Ego, which are sub-factors of Presence, in social satisfaction, psychological satisfaction, and physical satisfaction. Third, the sub-factors of Presence, Social Presence, Social Self-Reliance, and Ego, were found to have a high effect on the sub-factors of Participation Satisfaction, Social Satisfaction, and Psychological Satisfaction.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.21 no.5
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• pp.28-41
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• 2022

A road system with CV(Connected Vehicle)s, which is often referred to as a cooperative intelligent transportation system (C-ITS), provides various road information to drivers using an in-vehicle warning system. Road environments with CVs induce drivers to reduce their speed or change lanes to avoid potential risks downstream. Such avoidance maneuvers can be considered to improve driving behaviors from a traffic safety point of view. Thus, empirically evaluating how a given in-vehicle warning information affects driving behaviors, and monitoring of the correlation between them are essential tasks for traffic operators. To quantitatively evaluate the effect of in-vehicle warning information, this study develops a method to calculate compliance rate of drivers where two groups of speed profile before and after road information is provided are compared. In addition, conventional indexes (e.g., jerk and acceleration noise) to measure comfort of passengers are examined. Empirical tests are conducted by using PVD (Probe Vehicle Data) and DTG (Digital Tacho Graph) data to verify the individual effects of warning information based on C-ITS constructed in Seoul metropolitan area in South Korea. The results in this study shows that drivers tend to decelerate their speed as a response to the in-vehicle warning information. Meanwhile, the in-vehicle warning information helps drivers to improve the safety and comport of passengers.

• Journal of the Society of Disaster Information
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• v.19 no.3
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• pp.737-746
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• 2023

Purpose: Ground subsidence due to cavity can bring about various problems, such as casualties, decrease of the safety of the structures, and indirect social costs. Therefore, ground subsidence should be prevented through the exploration and recovery of the cavity under the pavements. Method: In this study, GPR exploration method was carried out on both actual roadway and mock-up site to compensate for the problems caused by excavation and restoration process. Result: This study compared the cavity scales obtained from GPR exploration results and the direct excavation of the identified cavity. It was confirmed that the predicted soil depth by GPR exploration was similar to the identified soil depth, but the predicted cavity scale by GPR exploration overestimated the longitudinal and cross-sectional widths compared to the identified cavity scale. Conclusion: Based on the correlation between the predicted cavity scales by GPR exploration, it is possible to qualitatively estimate the cavity scales using the empirical formula proposed in this study.

• Nuclear Engineering and Technology
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• v.25 no.1
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• pp.91-101
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• 1993

To predict accurately the thermal hydraulic behavior of light water reactors during normal or abnormal operation, the accurate estimation of the void distribution is required. Up to date, many techniques for predicting void fraction of two-phase flow systems have been suggested. Among these techniques, the drift-flux model is widely used because of its exact calculation ability and simplicity. However, to get more accurate prediction of void fraction using drift-flux model, slip and flow regime effects must be considered more properly In the drift-flux method, these two effects are accounted for by two drift-flux parameters ; $C_{o}$ and (equation omitted). At earlier stage, $C_{o}$ is measured in a circular tube. In this study, $C_{o}$ is experimentally determined by measuring local void fraction and vapor velocity distribution in a rectangular subchannel having 4 heating rods which simulates nuclear subchannels. The measurements are peformed with two-electrical conductivity probes which are known to be adequate for measuring local parameters. The experiments are performed at low flow rate and the system pressure less than 3 atmo spheric pressure. In this experiment, (equation omitted), is not measured, but quoted from well-known empirical correlation to formulate $C_{o}$. Finally, $C_{o}$ is expressed as a function of channel averaged void fraction. fraction.

• Journal of the Korea Institute of Building Construction
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• v.23 no.3
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• pp.221-229
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• 2023

This research aimed to conduct an empirical assessment of the penetration of chloride and sulfate ions into mortar sections using an anion exchange membrane(AEM) and laser-induced breakdown spectroscopy(LIBS). The study involved a simultaneous ion chromatography(IC) analysis and LIBS analysis performed on mortars immersed in varying concentrations of chloride and sulfate. The findings revealed that at the wavelengths specific to Chloride(837.59nm) and Sulfur(921.30nm), the LIBS intensity achieved using AEM surpassed that obtained with a paper substrate at equivalent penetration concentrations. A robust correlation was confirmed between LIBS intensity and chloride ion concentration. Furthermore, when juxtaposed with IC analysis concentration outcomes at identical depths, the AEM displayed a higher intensity. The research noted an enhancement in LIBS intensity and a diminution in errors within the low-concentration section when deploying AEM. However, for the Sulfur wavelength of 921.3nm, there remains a need to augment the sensitivity of the LIBS signal within the low-concentration section in future studies. The findings underscore the potential of employing AEM and LIBS for precise analysis of chloride and sulfate ion penetration into mortar sections. This strategy can aid in bolstering assessment precision and mitigating errors, particularly in regions with low concentrations. It is recommended to further research and develop methods to amplify the sensitivity of the LIBS signal for sulfur detection in low-concentration sections. In sum, the study accentuates the significance of employing advanced techniques like AEM and LIBS for efficacious and precise analysis in the domain of mortar section assessment.

• Journal of Industrial Convergence
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• v.21 no.4
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• pp.65-72
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• 2023

This study's purpose is to verify how the periodically designated auditor in the recently implemented periodic auditor designation system affects audit quality. In this study, hypotheses were established by reviewing previous studies, and 980 samples of 2019 and 2020 were selected for KOSPI-listed companies. Dechow & Dichev (2002)'s accrual quality was used as the dependent variable, and the effect of whether or not a company was periodically designated as an auditor and whether or not a Big 4 auditor was selected was empirically analyzed. As a result of the analysis and correlation analysis, a statistically significant difference was confirmed in the quality of the dependent variable accrual and the independent variable designated auditor (PA). However, as a result of the regression analysis model 1, it was found that the designated auditor was not significant, but it was confirmed that there was a significant difference in the control variables. Further analysis confirmed the difference in audit quality according to the Big 4 auditors. This study is significant in that it is a study that uses empirical data to study the effect of audit quality and the selection of regularly designated auditor companies after the introduction in 2019 and 2020. Due to the non-disclosure of government-designated companies, there is a limit that there may be a difference from the selection based on the researcher's published selection criteria.

• Korean Association of Arts Management
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• no.49
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• pp.87-115
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• 2019

The impact of "Korean wave" has gradually expanded in recent years, its spread trend can also be seen in the United States, South America, and even in Europe. As the earliest and largest importer of Korean culture, China's importance is self-evident. Based on the results of empirical analysis, and analyze the importance and satisfaction of each element that makes up the four factors(Music, Dance, Style, Story) with IPA method, as well as the impact of its rankings on K-POP fans phenomenon in China. The results of this study are organized as follows. Firstly, according to the analysis results, only 10.5% of the K-POP fans are male, and K-POP fans are generally young, their age mainly concentrates in the first half of the 20th (49.0%). Secondly, among the survey respondents, 65% of the fans have positive comments on the Korean Wave, most of K-POP fans obtain their idols' information through Internet, and 49.5% have consumption behaviors for their favorite idols. Thirdly, it can be seen from the data of survey results that fans attach the greatest attention to the importance and satisfaction of the melody elements in terms of music, and the performance effect in terms of dance, the appearance is chosen as the priority in terms of styling, as for the last factor, topicality, the broadcasting is the first choice. In view of the formation of the phenomenon of K-POP fans among Chinese Korean fans, by conducting the correlation analysis and research on the importance and satisfaction of each factor through data, this study is with great practical significance in academic research, it can be used as practical and meaningful material for the K-POP fans among Chinese Korean fans.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3C
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• pp.179-186
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• 2008

Pressuremeter test estimates the deformational properties of soil from the relationship between applied pressure and the displacement of cavity wall. It is general to utilize the reloading curve for the estimation of deformational properties of soil because the initial loading curve can be affected by the disturbance caused by boring. On the other hand, the instrumental resolution or the variation of measured data makes it hard to estimate the maximum shear modulus from pressuremeter test results. This study suggested the methodology estimating the maximum shear modulus from pressuremeter test directly, based on the curve fitting of reloading curve. In addition, the difference was taken into account between the stress state around the probe in reloading and that of the in-situ state. Pressuremeter tests were conducted for 15 cases using a large calibration chamber, together with a number of reference tests. The maximum shear moduli taken from suggested method were compared with those from empirical correlation and bender element test.

• Journal of Korea Entertainment Industry Association
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• v.13 no.5
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• pp.185-193
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• 2019

Young children facilitate their social and emotional development by doing a lot of play activities with their peers. As an empirical survey study, this study is aimed at analyzing how the peer play interaction influences peer competency and self-regulation. To achieve that, a questionnaire survey was conducted with 271 young children aged 5 years who were going to the kindergarten in the G district of Seoul. With the data collected in the survey, frequency analysis, descriptive statistics, reliability test, correlation analysis and regression analysis were conducted by SPSS program. The analysis results are presented as follows: firstly, peer play interaction positively influenced young children's sociability, pro-sociality, and leadership as their peer competency factors; secondly, peer play interaction positively influenced their patience, endurance of waiting, and adaptation as their self-regulation factors. This study drew the conclusion that peer play interaction is a critical variable to predict young children's peer competency and self-regulation. Therefore, it will be necessary to continuously develop a variety of play activity programs which young children can join in the inside and outside of kindergarten in order to helps young children improve their peer competency and self-regulation, and to actively connect the programs with Nuri curriculum.