• Journal of Educational Research in Mathematics
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• v.27 no.2
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• pp.157-170
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• 2017

Mathematics was the main domain of PISA 2012, and both paper-based and computer-based assessment of mathematics (CBAM) were conducted. PISA 2012 was the first large-scale computer-based mathematics assessment in Korea, and it is meaningful in that it evaluated students' mathematical literacy in problem situations using dynamic geometry, graph, and spreadsheet. Although Korea ranked third in CBAM, the use of ICT in mathematics lessons appeared to be low. On the other hand, this study focused on Singapore, which ranked first in CBAM. The Singapore Ministry of Education developed online programs such as AlgeTools and AlgeDisc, and implemented the programs in classes by specifying them in mathematics curriculum and textbooks. Thus, this study investigated influential factors on computer-based assessment of mathematics by comparing the results of Korea and Singapore, and aimed to provide meaningful evidence on the direction of Korea's ICT-based mathematics education. The results showed that ICT use at home for school related tasks, attitudes towards computers as a tool for school learning, and openness and perseverance of problem solving were positively associated with computer-based mathematics performance, whereas the use of ICT in mathematics class by teacher demonstration was negatively related. Efforts are needed to improve computer use and enhance teaching techniques related to ICT use in Korean math classes. Future research is recommended to examine how effectively teachers use ICT in mathematics class in Singapore.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.1
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• pp.53-57
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• 2010

The influence of CaO addition on the crystallization temperature, crystal types, and microstructure of L-A-S ($Li_2O-Al_2O_3-SiO_2$) glass-ceramics system fabricated from a coal bottom ash, produced at thermal power plant, was studied. The glass transition and crystallization temperatures were shifted to the higher temperature position with increasing CaO content in a non-isothermal analysis using a DTA. The major crystalline phases of L-A-S glass-ceramics system produced were identified as ${\beta}$-spodumene ($LiAlSi_2O_6$) and eucryptite ($LiAlSiO_4$). The glass-ceramics showed a bulk and surface crystallization behavior at a time. With increasing CaO content, the ${\beta}$-spodumene peak in XRD increased and some CaO-related phases were formed. The surface crystal grown from the exterior to the center in glass-ceramics showed various shapes by amount of CaO added. Some cracks were generated at the glass-ceramics containing CaO above 9 wt% due to the mismatch of thermal expansion coefficients between a ${\beta}$-spodumene and CaO-related crystal phases.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.48 no.1
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• pp.141-148
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• 2011

Most of the previous works on scene change detection algorithm focus on the detection of abrupt rather than gradual changes. In general, gradual scene change detection algorithms require heavy computation. Some of those approaches don't consider the error factors such as flashlights, camera or object movements, and special effects. Many scenes change detection algorithms based on the histogram show better performances than other approaches, but they have computation load problem. In this paper, we proposed a scene change detection algorithm with fast and accurate performance using the vertical and horizontal blocked slice images and their macro block informations. We apply graph cut partitioning algorithm for clustering and partitioning of video sequence using generated spatio-temporal histogram. When making spatio-temporal histogram, we only use the central block on vertical and horizontal direction for performance improvement. To detect camera and object movement as well as various special effects accurately, we utilize the motion vector and type information of the macro block.

• Journal of the Korean Institute of Gas
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• v.2 no.2
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• pp.18-25
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• 1998

According to the requirements of ANSI B3l.8, the pipe thickness is determined with hoop stress resulted from internal pressure. And the other loads induced by soil, vehicle, thermal expansion, ground subsidence, etc shall be evaluated rationally. There are two ways of calculating stress of buried gas pipeline. The first is FEM. FEM can calculate the stress regardless of the complexity of pipeline shape and boundary conditions. But it needs high cost and long time. The second is the way to use equation. The reliable equations to calculate the stress of buried gas pipeline was developed and have been used in designing pipeline and evaluating pipeline safety, But these equation are very difficult to understand and use for non-specialist. For easy calculation of non-specialist, the new computer program to calculate stress of buried natural gas pipeline have been developed. The stress is calculated by the equations and extrapolation of the graph resulted from FEM. The full paper is consist of series I and II. In this paper, series I, the calculating equation of the program is explained in detail.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.4
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• pp.284-288
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• 2009

With explosively growing PPI databases, the computational approach for a prediction and configuration of PPI network has been a big stream in the bioinformatics area. Recent researches gradually consider physicochemical properties of proteins and support high resolution results with integration of experimental results. With regard to current research trend, it is very close future to complete a PPI network configuration of each organism. However, direct applying the PPI network to real field is complicated problem because PPI network is only a set of co-expressive proteins or gene products, and its network link means simple physical binding rather than in-depth knowledge of biological process. In this paper, we suggest a protein functional flow model which is a directed network based on a protein functions' relation of signaling transduction pathway. The vertex of the suggested model is a molecular function annotated by gene ontology, and the relations among the vertex are considered as edges. Thus, it is easy to trace a specific function's transition, and it can be a constraint to extract a meaningful sub-path from whole PPI network. To evaluate the model, 11 functional flow models of Homo sapiens were built from KEGG, and Cronbach's alpha values were measured (alpha=0.67). Among 1023 functional flows, 765 functional flows showed 0.6 or higher alpha values.

• Journal of the Korean GEO-environmental Society
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• v.12 no.2
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• pp.35-43
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• 2011

Confined aquifer, which is separated with upper clayey or silty materials, is partially distributed at the depths of the sediments in Ddan-sum area on the lower Nakdong river. Measurements of groundwater levels at 13 sites explain that groundwater flow shows seasonally various due to seasonal rainfall and agricultural water use. From 9 long-term monitoring data of groundwater levels at 7 sites, 3 types of groundwater levels time series can be classified using principal component analysis. The first type is seen in the center of Ddan-sum and has a round-shape graph due to a weak response to stream water levels. The second type exists in the outer part of Ddan-sum and shows sharply peak-shape graph due to a rapid and strong response to stream water levels and rainfall. The last type, which is seen in a deep layer, has a periodicity by tital effect. From geochemical analysis at each monitoring sites, [$Ca-HCO_3$] type happens in the center of Ddan-sum far from Nakdong river, and [$Na-HCO_3$] and [$Ca-SO_4(Cl)$] types exist in the outer of Ddan-sum affected by river quality.

• Journal of the Korean Society of Radiology
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• v.16 no.7
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• pp.975-984
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• 2022

Since a linear transducer has an area of interest equal to the length of the transducer, the area of interest can be expanded using the virtual convex function installed in the device.However, it was thought that the change in the direction of the ultrasonic sound velocity according to the change in the visual area of interest would affect the image quality, so this was objectively confirmed. For this study, image evaluation and SNR·CNR of the phantom for ultrasound quality control were measured. As a result, in the phantom image evaluation, both images were able to identify structures in functional resolution, grayscale, and dynamic range. However, it was confirmed that the standard image was excellent in the reproducibility of the size and shape of the structure. As a result of SNR·CNR evaluation, SNR·CNR of most trapezoidal images was low, except for structures at specific locations. In addition, through the statistical analysis graph, it was further confirmed that the SNR and CNR for each depth decreased as the size of the cystic structure decreased. Through this study, it was confirmed that the use of the function has the advantage of providing a wide visual area of interest, but it has an effect on the image quality. Therefore, when using the virtual convex function, it is judged that the examiner should use it in an appropriate situation and conduct various studies to acquire high-quality images and to improve the understanding and proficiency of the equipment.

• Journal of the Korea Society of Computer and Information
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• v.28 no.10
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• pp.27-35
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• 2023

In this paper, we propose a process of increasing productivity by applying a deep learning-based defect detection and classification system to the prepreg fiber manufacturing process, which is in high demand in the field of producing composite materials. In order to apply it to toe prepreg manufacturing equipment that requires a solution due to the occurrence of a large amount of defects in various conditions, the optimal environment was first established by selecting cameras and lights necessary for defect detection and classification model production. In addition, data necessary for the production of multiple classification models were collected and labeled according to normal and defective conditions. The multi-classification model is made based on CNN and applies pre-learning models such as VGGNet, MobileNet, ResNet, etc. to compare performance and identify improvement directions with accuracy and loss graphs. Data augmentation and dropout techniques were applied to identify and improve overfitting problems as major problems. In order to evaluate the performance of the model, a performance evaluation was conducted using the confusion matrix as a performance indicator, and the performance of more than 99% was confirmed. In addition, it checks the classification results for images acquired in real time by applying them to the actual process to check whether the discrimination values are accurately derived.

• Journal of Service Research and Studies
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• v.14 no.2
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• pp.18-36
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• 2024

As interest in ESG has been increased, it is easy to find papers that empirically study that a company's ESG activities have a positive impact on the company's performance. However, research on what ESG activities companies should actually engage in is relatively lacking. Accordingly, this study systematically classifies ESG activities of companies and seeks to provide insight to companies seeking to plan new ESG activities. This study analyzes how Chinese manufacturing companies perform ESG activities based on their dynamic capabilities in the global economy and how they differ in their activities. This study used the ESG annual reports of 151 Chinese manufacturing listed companies on the Shanghai & Shenzhen Stock Exchange and ESG indicators of China Securities Index Company (CSI) as data. This study focused on the following three research questions. The first is to determine whether there are any differences in ESG activities between companies with high ESG scores (TOP-25) and companies with low ESG scores (BOT-25), and the second is to determine whether there are any changes in ESG activities over a 10-year period (2010-2019), focusing only on companies with high ESG scores. The results showed that there was a significant difference in ESG activities between high and low ESG scorers, while tracking the year-to-year change in activities of the top-25 companies did not show any difference in ESG activities. In the third study, social network analysis was conducted on the keywords of E/S/G. Through the co-concurrence matrix technique, we visualized the ESG activities of companies in a four-quadrant graph and set the direction for ESG activities based on this.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.11
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• pp.140-149
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• 1996

Cursive characters are written on an economical principle to reduce the motion of a pen in the limit of distinction between characters. That is, the pen is not lifted up to move for writing a next stroke, the pen is not moved at all, or connected two strokes chance their shapes to a similar and simple shape which is easy to be written. For these reasons, strokes and korean alphabets are not only easy to be changed, but also difficult to be splitted. In this paper, we propose a curvature stroke modeling method for splitting and matching by using a structural primitive. A curvature stroke is defined as a substroke which does not change its curvanture. Input strokes handwritten in a cursive style are splitted into a sequence of curvature strokes by segmenting the points which change the direction of rotation, which occur a sudden change of direction, and which occur an excessive rotation Each reference of korean alphabets is handwritten in a printed style and is saved as a sequence of curvature strikes which is generated by splitting process. And merging process is used to generate various sequences of curvature strikes for matching. Here, it is also considered that imaginary strokes can be written or omitted. By using a curvature stroke as a unit of recognition, redundant splitting points in input characters are effectively reduced and exact matching is possible by generating a reference curvature stroke, which consists of the parts of adjacent two korean alphasbets, even when the connecting points between korean alphabets are not splitted. The results showed 83.6% as recognition rate of the first candidate and 0.99sec./character (CPU clock:66MHz) as processing time.