• Journal of Power Electronics
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• v.15 no.4
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• pp.1026-1034
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• 2015

In this paper, a unified control strategy using the current space vector modulation (CSVM) technique is proposed and applied to a bidirectional three-phase DC/AC converter. The operation of the converter changes with the direction of the power flow. In the charging mode, it works as a buck type rectifier; and during the discharging mode, it operates as a boost type inverter, which makes it suitable as an interface between high voltage AC grids and low voltage energy storage devices. This topology has the following advantages: high conversion efficiency, high power factor at the grid side, tight control of the charging current and fast transition between the charging and discharging modes. The operating principle of the mode analysis, the gate signal generation, the general control strategy and the transition from a constant current (CC) to a constant voltage (CV) in the charging mode are discussed. The proposed control strategy has been validated by simulations and experimental results obtained with a 1kW laboratory prototype using supercapacitors as an energy storage device.

• Journal of IKEEE
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• v.23 no.2
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• pp.557-570
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• 2019

In this study, a novel hierarchical approach is investigated to extract coronary vessel from X-ray angiogram. First, we propose to combine Decimation-free Directional Filter Bank (DDFB) and Homographic Filtering (HF) in order to enhance X-ray coronary angiographic image for segmentation purposes. Because the blood vessel ensures that blood flows in only one direction on vessel branch, the DDFB filter is suitable to be used to enhance the vessels at different orientations and radius. In the combination with HF filter, our method can simultaneously normalize the brightness across the image and increases contrast. Next, a coarse-to-fine strategy for iterative segmentation based on Otsu algorithm is applied to extract the main coronary vessels in different sizes. Furthermore, we also propose a new approach to segment very small vessels. Specifically, based on information of the main extracted vessels, we introduce a new method to extract junctions on the vascular tree and level of nodes on the tree. Then, the window based segmentation is applied to locate and extract the small vessels. Experimental results on our coronary X-ray angiography dataset demonstrate that the proposed approach can outperform standard method and attain the accuracy of 71.34%.

• Journal of Korean Society for Quality Management
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• v.49 no.1
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• pp.31-45
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• 2021

Purpose: A noncentral composite design method is to be developed to explore farther region for the first factorial design. A general guideline for sequential experimentation is provided. Methods: (1) A non-overlapping noncentral composite design (NNCD) is developed, in which the second factorial design shares one design point that indicates the best response value in the first factorial design. (2) Four composite designs are compared in terms of the four design evaluation criteria, which are D-, A, G, and I-optimality. (3) A follow-up design strategy is suggested based on the interaction effect, direction of improvement, number of factors. Results: (1) NNCD and model building method are presented, which is useful for exploring farther region from first factorial design block. (2) The performances of the four composite designs are compared. (3) A follow-up design strategy is suggested. Conclusion: (1) NNCD will be useful to explore farther region for the first factorial design. (2) A follow-up design strategy can be beneficial to the experimental practitioners for product and process design and improvement.

• Journal of information and communication convergence engineering
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• v.20 no.2
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• pp.103-112
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• 2022

The goal of pattern mining is to identify novel patterns in a database. High utility itemset mining (HUIM) is a research direction for pattern mining. This is different from frequent itemset mining (FIM), which additionally considers the quantity and profit of the commodity. Several algorithms have been used to mine high utility itemsets (HUIs). The original BPSO algorithm lacks local search capabilities in the subsequent stage, resulting in insufficient HUIs to be mined. Compared to the transfer function used in the original PSO algorithm, the V-shaped transfer function more sufficiently reflects the probability between the velocity and position change of the particles. Considering the influence of the acceleration factor on the particle motion mode and trajectory, a nonlinear acceleration strategy was used to enhance the search ability of the particles. Experiments show that the number of mined HUIs is 73% higher than that of the original BPSO algorithm, which indicates better performance of the proposed algorithm.

• International Journal of Advanced Culture Technology
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• v.11 no.3
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• pp.321-326
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• 2023

The purpose of this study is to create and present a formalized module of ISP (Information Strategy Plan), a smart factory consulting method that is helpful to companies or consultants who will build smart factories. Order of study is First, the theoretical research direction is established through the investigation of related papers. Second, ISP policy research practices are compared to derive practical implementation methods. Third, in order to derive a standardized module method related to the final smart factory ISP, related cases of the government and individuals are compared. As a result of previous research, ISP (Information Strategy Planning), a consulting methodology, is similar to Deming's PDCA, and is regarded as Plan (environment and current status analysis), Do (establishment of future model goals), Check (establishment of implementation plan), and Act (follow-up management). As a result of the study, we obtained the following results. The first step is to analyze the current status and identify the purpose of introduction and problems in plant operation. In the second step, establish a consulting plan and derive a proposal description, strategic task, and master plan. Step 3 establishes detailed action plans, evaluates consulting outputs and consulting, and reports performance. Step 4 is established as follow-up management consulting. The limitation of the study is that although related data were compared to develop the consulting methodology into a standardized module, FGI analysis through experts or Delphi survey were not conducted, so there is a limit to the reliability of the mapping results.

• Journal of Korea Society of Industrial Information Systems
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• v.14 no.2
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• pp.59-71
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• 2009

A great number of companies continue to invest heavily in information technology such as SCM The reasons for this investment vary, but the principal belief is that they will use the technology to gain competitive advantage in today's highly dynamic and changing business market. In order to identify the SCM management performance, this study investigates the impacts of information technology strategy(operation-oriented and market-oriented) on the information technology investment direction(internal system orientation and external system orientation), process innovation level and management performance(non-financial performance and financial performance). This study collected data on-line and off-line from enterprises which implement the supply chain management. The 82 responses were used for the statistical analysis.

• Journal of Research and Publication Ethics
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• v.4 no.2
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• pp.13-17
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• 2023

Purpose: EAJBE is actively responding to changes in academic paradigms at domestic and abroad and is carrying out measures to maximize synergy effects between academic fields with the goal of being at the world level. This study aims to present a developmental strategy for EAJBE to grow into an academic journal with international public trust and prepare for future changes. Research design, data and methodology: This paper identifies the current status from the first issue of EAJBE to the present, and analyzes the overall development strategy and direction. Results: EAJBE continues to strengthen long-term investment for internationalization and activities to attract members of excellent scholars. Specifically, first of all, EAJBE aims to operate responsible academic journals, such as guaranteeing the long term of the president of the academic society, the chairman of the editorial board, and the editor-in-chief. EAJBE also focuses on expanding investment for internationalization from a long-term perspective. Finally, EAJBE actively strives for academic exchanges between scholars abroad and at home. Conclusions: EAJBE was indexed in the KCI of the Korea Research Foundation and currently operates a rigorous academic journal to be indexed in the SCOPUS. Already, EAJBE is doing its best to become a successful model for Korean academic journals. EAJBE's path forward will be the first one that no academic society has ever reached as the world's top academic journal.

• The Journal of Korean Association of Computer Education
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• v.9 no.4
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• pp.25-34
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• 2006

Although the e-learning system is being introduced in elementary and secondary education, incorporating it into the regular curriculum is difficult. Other problems include the lack of sessions and connection to regular courses in realistically applying project-based learning in the regular school curriculum. Therefore. this study established, applied, and analyzed the blended learning strategy to resolve such issues. Specifically, a theoretical investigation on the concept of blended learning and IT-oriented, project-based learning was conducted. The theme for learning based on integrated courses was also selected, and the 5-stage project-based teaching and learning strategy, concretized. The concretization strategy involved discussion, role division, and alternative evaluation strategy. The class progressed in formats of on-class online, on-class offline and off-class online. As a result, students experienced inconvenience since the project only lasted for a short period of time. Nonetheless, they responded positively to the effect of project-based learning in general. This study was able to suggest the possibility of applying e learning in regular school curriculum and propose the direction for digital and learner oriented teaching.

• Journal of Korea Society of Digital Industry and Information Management
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• v.13 no.1
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• pp.173-183
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• 2017

The purpose of this study is to find out the difference of sense of self-efficacy and stress encountering strategy of university students under the stress situation depending on the smart-phone user group (addiction group, general user group). For this purpose, the study issues are established as follows. First, it has analyzed what is the correlation of smart-phone addiction, sense of self-efficacy, and stress encountering strategy. Second, it has studied if there is any difference of sense of self-efficacy and stress encountering strategy for the smart-phone user group. In order to verify such study issues, For 1,670 university students in the Chungcheong area, smart-phone addiction scale, sense of self-efficacy scale, and stress encountering method scale were administered. Looking into the study result, first, as a result of the relativity analysis, it displayed the correlation of preference of test difficulty, self-control efficacy and important negative from the smart-phone addiction and sense of self-efficacy. In addition, all sub-variables of smart-phone addiction and avoidance orientation from the stress encountering strategy displayed the important positive correlation, and from the smart-phone addiction, the virtual world orientation and pursuit of social-support displayed the important negative correlations, and all sub-variables (interference with ordinary living, virtual world striving direction, withdrawal, resistance) of smart-phone addiction and problem solving-orientation displayed the negative correlation. Second, as a result of verification for the difference of the smart-phone addiction group and general use group following the sense of self-efficacy, the general use group is shown to have higher self-control efficacy sense than the addiction group. And third, as a result of verifying the difference of stress encountering following the smart-phone addiction group and general use group, the addiction group is shown to be lower than the general use group in terms of social support pursuit and problem solution orientation with the avoidance orientation shown to be higher. This type of result is expected to provide the base data when developing the smart-phone addiction preventive education program by finding out in details for the characteristics of smart-phone addiction group for university students.

• Journal of Korea Technology Innovation Society
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• v.11 no.4
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• pp.639-670
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• 2008

The BSC which was proposed by Kaplan and Norton, is being used as a general performance measurement tool in various firms and industries. BSC approach links strategic objectives with specific operation indices and it can efficiently evaluate the attainment of the goals of the firm. This study is a BSC based case of the government R&D institute which is staffed with knowledge experts in the research areas. In order to bring a major change to a public research organization and shape a strategy focused organization, it is essential to understand the proper methodology of the whole construction process of BSC from the mission of the institute through the establishment of vision and strategic direction, KPI building, and a strategy map set, to the implementation of the BSC monitoring system. By investigating the application process, in this research we intend to provides useful implications in the BSC construction process of public research agencies.