• Journal of IKEEE
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• v.27 no.4
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• pp.486-493
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• 2023

In this paper, we propose an automatic hand gesture area extraction and recognition technique using FMCW radar-based point cloud and LSTM. The proposed technique has the following originality compared to existing methods. First, unlike methods that use 2D images as input vectors such as existing range-dopplers, point cloud input vectors in the form of time series are intuitive input data that can recognize movement over time that occurs in front of the radar in the form of a coordinate system. Second, because the size of the input vector is small, the deep learning model used for recognition can also be designed lightly. The implementation process of the proposed technique is as follows. Using the distance, speed, and angle information measured by the FMCW radar, a point cloud containing x, y, z coordinate format and Doppler velocity information is utilized. For the gesture area, the hand gesture area is automatically extracted by identifying the start and end points of the gesture using the Doppler point obtained through speed information. The point cloud in the form of a time series corresponding to the viewpoint of the extracted gesture area is ultimately used for learning and recognition of the LSTM deep learning model used in this paper. To evaluate the objective reliability of the proposed technique, an experiment calculating MAE with other deep learning models and an experiment calculating recognition rate with existing techniques were performed and compared. As a result of the experiment, the MAE value of the time series point cloud input vector + LSTM deep learning model was calculated to be 0.262 and the recognition rate was 97.5%. The lower the MAE and the higher the recognition rate, the better the results, proving the efficiency of the technique proposed in this paper.

• Journal of Service Research and Studies
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• v.13 no.4
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• pp.1-23
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• 2023

Tablet PCs are gaining increasing popularity in today's context, offering convenience in store operations. However, some customers may have complaints. From the perspective of shadow labor, customers may perceive using tablet PCs as additional tasks, implying that tasks have been transferred from service staff to customers themselves. Therefore, this study aims to investigate the causes of customers' perception of shadow labor when using tablet PCs (perceived difficulty of use and perceived compulsion to use) and how these perceptions can influence their intention to reuse tablet PC ordering services. Additionally, the study examines whether customers' perception of shadow labor is influenced by digital literacy and information overload and investigates the positive impact of benefits arising from using tablet PCs on their perception of shadow labor. This research conducted an online survey through the Chinese survey specialist website "Wenjuanxing," targeting customers who use tablet PCs to place orders in restaurants. After collecting a total of 376 valid data points, demographic characteristics, frequency analysis, reliability analysis, validity analysis, correlation analysis, and regression analysis were conducted using SPSS 24.0. The empirical results from the 376 respondents reveal that digital literacy and information overload affect the perception of shadow labor and also influence the intention to reuse tablet PC ordering services. Furthermore, benefits showed significant moderating effects on these relationships.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.22 no.5
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• pp.19-29
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• 2023

The accident rate in South Korea is simply classified according to the road type and the number of lanes, but other countries apply various factors affect accidents. In this study, national highways where accidents occurred were divided into urban, rural, older, and modern roads using TAAS(Traffic Accident Analysis System) data, and a model of accident costs savings is suggested. As a result of analyzing 1,416.2 km, the fatality rate(person/100mil-vehicle·km) was 4.21 for urban-older, 1.37 for urban-modern, 2.18 for rural-older, and 0.99 for rural-modern roads. The rates of urban roads had a higher result than rural. The injury rate(person/100mil-vehicle·km) for urban-older was 182.63, that for urban-modern was 103.42, that for rural-older was 67.44, and that for rural-modern road was 42.96, which showed a similar pattern to fatality rates. Accident rates of a modern road were much lower than the KDI Guideline. The benefit of applying the result of this study was calculated and the valuation of accident costs savings is increased from 0.6% to 14.1%, while B/C is improved from 0.626 to 0.724.

• Journal of the Korean Society of Radiology
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• v.17 no.6
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• pp.1009-1015
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• 2023

This study was a one-group pretest-posttest design experimental study that attempted to verify the effects of applying the Havruta learning method on the academic self-efficacy, academic achievement, and communication skills of radiology college students. This study was conducted from May 1 to June 23, 2023, and applied the Havruta learning method for 6 weeks to 38 second-year radiologists taking a radiology technology course at a university in Jeollanam-do. SPSS/WIN 21.0 was used for data analysis, the reliability of the scale was verified, the subject's general characteristics, pre-test values and post-test values for measurement variables were verified with descriptive statistics, and the difference between before and after the Havruta learning method was verified with paired t-test. Research results show that the Havruta learning method improves academic self-efficacy (t=-2.70, p<.001), academic achievement (t=-2.87, p=.006), and communication skills (t=-2.76, p=.008). showed a statistically significant difference. As a result, Havruta learning method was confirmed as an effective learning method that improves academic self-efficacy, academic achievement, and communication skills of radiology college students. In the future, expanded application of the Havruta learning method will be necessary.

• Journal of Soil and Groundwater Environment
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• v.28 no.6
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• pp.71-89
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• 2023

A groundwater potential map (GPM) was built for the Nakdonggang River Basin based on ten variables, including hydrogeologic unit, fault-line density, depth to groundwater, distance to surface water, lineament density, slope, stream drainage density, soil drainage, land cover, and annual rainfall. To integrate the thematic layers for GPM, the criteria were first weighted using the Analytic Hierarchical Process (AHP) and then overlaid using the Technique for Ordering Preferences by Similarity to Ideal Solution (TOPSIS) model. Finally, the groundwater potential was categorized into five classes (very high (VH), high (H), moderate (M), low (L), very low (VL)) and verified by examining the specific capacity of individual wells on each class. The wells in the area categorized as VH showed the highest median specific capacity (5.2 m³/day/m), while the wells with specific capacity < 1.39 m³/day/m were distributed in the areas categorized as L or VL. The accuracy of GPM generated in the work looked acceptable, although the specific capacity data were not enough to verify GPM in the studied large watershed. To create GPMs for the determination of high-yield well locations, the resolution and reliability of thematic maps should be improved. Criterion values for groundwater potential should be established when machine learning or statistical models are used in the GPM evaluation process.

• Journal of Venture Innovation
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• v.5 no.2
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• pp.1-14
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• 2022

Mobile shopping goes beyond the level of a tool that simply supports consumers' shopping in-store and creates a new level of experience for consumers through offline connection. It is important to acquire new customers in order to gain a competitive advantage through mobile shopping, but it is more important to maintain a continuous transaction relationship with the secured customers. Existing mobile shopping-related studies can be largely classified into three categories such as a study on the characteristics of mobile consumers, a study on the characteristics of a mobile shopping mall, and a study on the characteristics of mobile shopping itself. Therefore, this study aimed to analyze the impact of perceived value, perceived risk, and innovativeness on trust in mobile shopping. In order to investigate the impact of perceived value, perceived risk, consumer innovativeness on the trust in mobile shopping, consumers who have experience in purchasing products through mobile were investigated. The data collected in this study were verified the reliability and validity of the measurement items based on the measurement validation process. In this study, regression analysis was performed by selecting perceived value, perceived risk, innovativeness as independent variables, and trust as dependent variables. As a result of the analysis, perceived value, innovativeness had a positive impact on trust and perceived risk had a negative impact on trust. As a result of analysis, three hypotheses were supported. Finally, implications of the research are presented, and limitations and directions for future research are described.

• Industry Promotion Research
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• v.8 no.4
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• pp.69-79
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• 2023

This study sought to propose ways to improve the happiness of Chinese product designers by verifying whether grit moderates the effect of job stress on happiness through professional values. A purposively sampled participants of 335 Chinese product designers living in Guangdong Province, southern China, were selected. Data analysis was performed using SPSS PC+ Win. Ver. 26.0 and PROCESS Macro ver. 4.2. The statistical techniques applied were frequency analysis, reliability analysis, correlation analysis, and moderated mediation effect analysis. The research results are as follows. First, job stress showed a negative correlation with professional value and grit, but did not show a significant correlation with happiness. Except for job stress, there was a positive significant correlation between other variables. Second, the conditional indirect effect was significant when grit was M-SD, M, or M+SD. M+SD. Therefore, the moderated mediating role of grit was verified. However, as professional value increased, grit played a role in increasing happiness. Still, in the path of job stress -> professional value -> happiness, grit did not buffer the negative effect of job stress on happiness through professional stress. Suggestions were made to improve the happiness of product designers using professional values and grit.

• Journal of the Korean Applied Science and Technology
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• v.40 no.5
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• pp.1092-1103
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• 2023

This study is a study to investigate how the achievement goal orientation of domestic winter sports participants has an effect on fun factors and participation satisfaction. A total of 326 questionnaires were used in this study, SPSS(Version 27.0) was used as a data processing method, and frequency analysis, reliability analysis, exploratory factor analysis, correlation analysis, and multiple regression analysis were used as statistical methods. The results of verifying the statistical effects of achievement goal tendency, fun factors, and participation satisfaction are as follows. First, as a result of verifying the effect of achievement goal orientation on fun factors, self-goal orientation and task goal propensity, which are sub-factors of achievement goal orientation, had significant effects on exercise ability, exercise utility, promotion of friendship, and self-satisfaction factors. Second, self-goal and task goal propensity, which are sub-factors of achievement goal orientation, had significant effects on facilities, costs, classes, interpersonal relationships, and health factors. Third, the sub-factors of fun factors such as exercise ability, exercise utility, promotion of friendship, and self-satisfaction had significant impacts on facilities, costs, lessons, interpersonal relationships and health factors.

• International conference on construction engineering and project management
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• 2011.02a
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• pp.432-438
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• 2011

The purpose of the present thesis is to develop bankruptcy prediction models capable of being applied to the Korean construction industry and to deduce an optimal model through comparative evaluation of final developed models. A study population was selected as general contractors in the Korean construction industry. In order to ease the sample securing and reliability of data, it was limited to general contractors receiving external audit from the government. The study samples are divided into a bankrupt company group and a non-bankrupt company group. The bankruptcy, insolvency, declaration of insolvency, workout and corporate reorganization were used as selection criteria of a bankrupt company. A company that is not included in the selection criteria of the bankrupt company group was selected as a non-bankrupt company. Accordingly, the study sample is composed of a total of 112 samples and is composed of 48 bankrupt companies and 64 non-bankrupt companies. A financial ratio was used as early predictors for development of an estimation model. A total of 90 financial ratios were used and were divided into growth, profitability, productivity and added value. The MDA (Multivariate Discriminant Analysis) model and BLRA (Binary Logistic Regression Analysis) model were used for development of bankruptcy prediction models. The MDA model is an analysis method often used in the past bankruptcy prediction literature, and the BLRA is an analysis method capable of avoiding equal variance assumption. The stepwise (MDA) and forward stepwise method (BLRA) were used for selection of predictor variables in case of model construction. Twenty two variables were finally used in MDA and BLRA models according to timing of bankruptcy. The ROC-Curve Analysis and Classification Analysis were used for analysis of prediction performance of estimation models. The correct classification rate of an individual bankruptcy prediction model is as follows: 1) one year ago before the event of bankruptcy (MDA: 83.04%, BLRA: 93.75%); 2) two years ago before the event of bankruptcy (MDA: 77.68%, BLRA: 78.57%); 3) 3 years ago before the event of bankruptcy (MDA: 84.82%, BLRA: 91.96%). The AUC (Area Under Curve) of an individual bankruptcy prediction model is as follows. : 1) one year ago before the event of bankruptcy (MDA: 0.933, BLRA: 0.978); 2) two years ago before the event of bankruptcy (MDA: 0.852, BLRA: 0.875); 3) 3 years ago before the event of bankruptcy (MDA: 0.938, BLRA: 0.975). As a result of the present research, accuracy of the BLRA model is higher than the MDA model and its prediction performance is improved.

• Tunnel and Underground Space
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• v.33 no.5
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• pp.348-372
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• 2023

In relation to the high-level radioactive waste disposal project in deep fractured rock aquifer environments, it is essential to evaluate hydrogeological characteristics for evaluating the suitability of the site and operational stability. Such subsurface hydrogeological data is obtained through in-situ tests using boreholes excavated at the target site. The accuracy and reliability of the investigation results are directly related to the selection of appropriate test methods, the performance of the investigation system, standardization of the investigation procedure. In this report, we introduce the detailed procedures for the representative test method, the constant pressure injection test (CPIT), which is used to determine the key hydrogeological parameters of the subsurface fractured rock aquifer, namely hydraulic conductivity and storativity. This report further refines the standard test method suggested by the KSRM in 2022 and includes practical field application case conducted in volcanic rock aquifers where this investigation procedure has been applied.