• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.3
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• pp.70-76
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• 2022

Recently, the demand for ultra-precision processing has increased owing to the increase in the demand for high-performance ultra-precision optical parts in the fields of information technology (IT), bio, healthcare, aerospace, and future automobiles. In this study, a performance improvement of a multi-stage pump was achieved by improving the pump casing structure rather than using the existing performance improvement method. To verify the performance improvement, the CFD analysis reliability of the existing pump, Pump A, was verified using the FLUENT app in the analysis software ANSYS, and the pump casing was improved through the verified CFD analysis of Pump B. Therefore, we want to analyze the performance improvement.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.119-130
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• 2023

Among the various elements of probabilistic safety assessment (PSA), human failure events (HFEs) and their dependencies are major contributors to the quantification of risk of a nuclear power plant. Currently, the dependency among HFEs is reflected using a post-processing method in PSA, wherein several drawbacks, such as limited propagation of minimal cutsets through the fault tree and improper truncation of minimal cutsets exist. In this paper, we propose a method to model the HFE dependency directly in a fault tree using the if-then-else logic. The proposed method proved to be equivalent to the conventional post-processing method while addressing the drawbacks of the latter. We also developed a software tool to facilitate the implementation of the proposed method considering the need for modeling the dependency between multiple HFEs. We applied the proposed method to a specific case to demonstrate the drawbacks of the conventional post-processing method and the advantages of the proposed method. When applied appropriately under specific conditions, the direct fault-tree modeling of HFE dependency enhances the accuracy of the risk quantification and facilitates the analysis of minimal cutsets.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.3
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• pp.123-133
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• 2022

Cultural tourism is a form of tourism based on national cultural identity with the participation of the community to preserve and promote traditional cultural values. Cultural tourism is a trend of many countries in the world, it is suitable for the context in the Mekong Delta, Vietnam. Cultural tourism is very good for poverty reduction activities, so it is considered a direction of socio-economic development. The study's goal is to look at the factors that influence the development of cultural tourism in Vietnam's Mekong Delta. Survey findings from 1275 survey samples in the Mekong Delta, Vietnam, were used to compile the research data. Cronbach's Alpha reliability coefficient; exploratory factor analysis EFA; CFA confirmatory factor; SEM linear regression analysis are used to analyze and assess scales using SPSS 20, AMOS 24 software. According to the findings of the SEM model study, there are six factors that influence the development of cultural tourism in the Mekong Delta of Vietnam, including policy development tourism, infrastructure for tourism, human resources for tourism, tourism resources, geographic location, tourism products, and services. A discussion on administration is proposed to the development of cultural tourism in the Mekong Delta, Vietnam, based on the research findings.

• Journal of Information Processing Systems
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• v.19 no.3
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• pp.394-406
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• 2023

In this study, a real-time surveillance system using Internet of Things technology is proposed for vaccine cold chains. This system fully visualizes vaccine transport and storage. It comprises a 4G gateway module, lowpower and low-cost wireless temperature and humidity collection module (WTHCM), cloud service software platform, and phone app. The WTHCM is installed in freezers or truck-mounted cold chain cabinets to collect the temperature and humidity information of the vaccine storage environment. It then transmits the collected data to a gateway module in the radiofrequency_physical layer (RF_PHY). The RF_PHY is an interface for calling the bottom 2.4-GHz transceiver, which can realize a more flexible communication mode. The gateway module can simultaneously receive data from multiple acquisition terminals, process the received data depending on the protocol, and transmit the collated data to the cloud server platform via 4G or Wi-Fi. The cloud server platform primarily provides data storage, chart views, short-message warnings, and other functions. The phone app is designed to help users view and print temperature and humidity data concerning the transportation and storage of vaccines anytime and anywhere. Thus, this system provides a new vaccine management model for ensuring the safety and reliability of vaccines to a greater extent.

• Journal of Ocean Engineering and Technology
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• v.38 no.3
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• pp.103-114
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• 2024

Remote sensing wave observation data are crucial when analyzing ocean waves, the main external force of coastal disasters. Nevertheless, it has limitations in accuracy when used in low-wind environments. Therefore, this study collected the raw data from MIROS Wave and Current Radar (MWR) and wave radar at the Ieodo Ocean Research Station (IORS) and applied the optimal filter by combining filters provided by MIROS software. The data were validated by a comparison with South Jeju ocean buoy data. The results showed it maintained accuracy for significant wave height, but errors were observed in significant wave periods and extreme waves. Hence, this study used an artificial neural network (ANN) to improve these errors. The ANN was generalized by separating the data into training and test datasets through stratified sampling, and the optimal model structure was derived by adjusting the hyperparameters. The application of ANN effectively improved the accuracy in significant wave periods and high wave conditions. Consequently, this study reproduced past wave data by enhancing the reliability of the MWR, contributing to understanding wave generation and propagation in storm conditions, and improving the accuracy of wave prediction. On the other hand, errors persisted under high wave conditions because of wave shadow effects, necessitating more data collection and future research.

• Journal of The Korean Association of Information Education
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• v.23 no.2
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• pp.131-139
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• 2019

From 2019, software education has become a required subject for all elementary school students. However, many teachers are still unfamiliar with how the classes should be instructed. So this paper presented the meaning, detailed competencies and achievement standard in order to help in the collection, analysis and representation of data among the computational thinking that are key to software education. And it also suggested the applicability of the classes. The full course of the paper is summarized as follows. First, existing studies have summarized the meaning, detail and achievement standard of data related competencies. Based on this, a preliminary investigation was instructed. Pilot study carried out both FGI and closed questions at the same time. This was done in response to the survey's questionnaire reflecting the opinions of experts. Second, the results of the questionnaire generated as a result of the above were verified for validity, stability, and reliability among the PhD, PhD courses, software education teachers, and software education workers. Third, I developed and applied the five lessons as a class objective as 'Choosing collection method-Select the collection method according to the problem situation.', 'Searching for meaning of data-Understand what the analyzed data mean..', 'Using various expression methods-Use a variety of expression tools.' using the backward design model to integrate education, class, and assessment. As a result, the detailed competencies of data collection, analysis, and representation and achievement standard were presented. This may help in setting specific and specific criteria for what direction classes are recommended when planning data-related classes in elementary schools.

• Journal of Distribution Science
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• v.16 no.5
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• pp.71-81
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• 2018

Purpose - Our research aims to investigate the mediating effect of employee creativity on the relationship between intrinsic motivation and job performance using relationship using Chinese department salespeople samples. Another objective of this study is to be clear boundary conditions that strengthen or weaken the effects of intrinsic motivation on work outcomes (i.e., employee creativity and job performance). Drawing on JD-R theory, we suggest that the two types of coworker support play differential moderating roles in the intrinsic motivation, employee creativity relationship by increasing or decreasing job resources and demands in different ways. Research design, data, and methodology - This empirical study data were collected from gathered from a sample of full time salespeople in China. A total of 550 questionnaires were distributed and 300 responses were collected, indicating a response rate of 84.0%. Working with a sample of 300 salespeople working in a department store in China. SPSS 18.0, Process 2.16 Macro, and M-Plus 8.0 software were used in the data analysis. Descriptive statistics were used to evaluate the distribution of the employee profiles and correlations between variables. M-Plus 8.0 software was used to test the model fit, validity and reliability of the variables. Finally, all research hypotheses was estimated by SPSS Macro 2.16. Results - To test our research hypotheses, we employed an analytical strategy suggested by Hayes (2013; 2015) and Shrout and Bolger (2002). In this study, we tested the relationship between intrinsic motivation and job performance throughout employee creativity. Results showed intrinsic motivation and job performance was partially mediated by employee creativity. The positive relationship between intrinsic motivation and employee creativity when coworker emotional support was high than when it was low. In contrast, the positive association between intrinsic motivation and employee creativity was stronger when coworker instrumental support was low than when it was high. Coworker emotional and instrumental support further moderated the indirect effect of intrinsic motivation on job performance through employee creativity. Conclusions - This study extends the conceptual model and empirical researches in coworker supports literature by representing a fundamental mechanism of how salespeople's intrinsic motivation and job performance throughout employee creativity.

• Journal of Internet Computing and Services
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• v.22 no.4
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• pp.1-11
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• 2021

As the Internet developed, various and complex cyber attacks began to emerge. Various detection systems were used outside the network to defend against attacks, but systems and studies to detect attackers inside were remarkably rare, causing great problems because they could not detect attackers inside. To solve this problem, studies on the lateral movement detection system that tracks and detects the attacker's movements have begun to emerge. Especially, the method of using the Remote Desktop Protocol (RDP) is simple but shows very good results. Nevertheless, previous studies did not consider the effects and relationships of each logon host itself, and the features presented also provided very low results in some models. There was also a problem that the model could not explain why it predicts that way, which resulted in reliability and robustness problems of the model. To address this problem, this study proposes an interpretable RDP-based lateral movement detection system using page rank algorithm and SHAP(Shapley Additive Explanations). Using page rank algorithms and various statistical techniques, we create features that can be used in various models and we provide explanations for model prediction using SHAP. In this study, we generated features that show higher performance in most models than previous studies and explained them using SHAP.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.54-62
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• 1995

This paper is a study on a speed control of an induction motor used the MRA-DSM(Mode1 Reference Adaptive-Discrete Sliding Mode) controller. In this paper, when controls motor speed, DSM algorithm is proposed for having Robustness against disturbance and parameter variation. and it is also proposed MRA-DSM including the additional load model reference algorithm, which can be compensated the discontinuous control imputs at sliding mode and followed the model Preference independent of parameter variation of control subjects. The control system is composed of the parallel processing control system using the microprocessor for maximizing the performance of control systems and the real time processing. Also it simplifies the hardware composed of controlling the system by software and improves the reliability of the system. And while MRA-DSM control, faster response characteristics of 27.2 % is obtained than DSM control.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.5
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• pp.406-414
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• 2014

In this paper, it is introduced characteristics of FMCW-type Radar Altimeter for KUH, and its defects occurred during ground/flight test in initial product phase. In addition, it is also described 'data/control flow model' based fault analysis results of S/W and processes of verifying improvement design through flight test as well as aircraft system integration test called MEP SIL. As a result of design improvement and verification, it is validated that settling the defects and improving not only safety but also capability of the KUH.