• Korean Journal of Radiology
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• v.23 no.6
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• pp.615-624
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• 2022

Objective: To compare the therapeutic outcomes of laparoscopic hepatic resection (LHR) and laparoscopic radiofrequency ablation (LRFA) for single subcapsular hepatocellular carcinoma (HCC). Materials and Methods: We screened 244 consecutive patients who had received either LHR or LRFA between January 2014 and December 2016. The feasibility of LRFA in patients who underwent LHR was retrospectively assessed by two interventional radiologists. Finally, 60 LRFA-feasible patients who had received LHR and 29 patients who had received LRFA as the first treatment for a solitary subcapsular HCC between 1 cm and 3 cm were finally included. We compared the therapeutic outcomes, including local tumor progression (LTP), recurrence-free survival (RFS), and overall survival (OS) between the two groups before and after propensity score (PS) matching. Multivariable Cox proportional hazard regression was also used to evaluate the difference in OS and RFS between the two groups for all 89 patients. Results: PS matching yielded 23 patients in each group. The cumulative LTP and OS rates were not significantly different between the LHR and LRFA groups after PS matching (p = 0.900 and 0.003, respectively). The 5-year LTP rates were 4.6% and 4.4%, respectively, and OS rates were 100% and 90.7%, respectively. The RFS rate was higher in LHR group without statistical significance (p = 0.070), with 5-year rates of 78.3% and 45.3%, respectively. OS was not significantly different between the LHR (reference) and LRFA groups in multivariable analyses, with a hazard ratio (HR) of 1.33 (95% confidence interval, 0.12-1.54) (p = 0.818). RFS was higher in LHR (reference) than in LRFA without statistical significance in multivariable analysis, with an HR of 2.01 (0.87-4.66) (p = 0.102). Conclusion: There was no significant difference in therapeutic outcomes between LHR and LRFA for single subcapsular HCCs measuring 1-3 cm. The difference in RFS should be further evaluated in a larger study.

• Korean Journal of Radiology
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• v.24 no.8
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• pp.761-771
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• 2023

Objective: To investigate the association among the electrode placement method, electrode type, and local tumor progression (LTP) following percutaneous radiofrequency ablation (RFA) for small hepatocellular carcinomas (HCCs) and to assess the risk factors for LTP. Materials and Methods: In this retrospective study, we enrolled 211 patients, including 150 males and 61 females, who had undergone ultrasound-guided RFA for a single HCC < 3 cm. Patients were divided into four combination groups of the electrode type and placement method: 1) tumor-puncturing with an internally cooled tip (ICT), 2) tumor-puncturing with an internally cooled wet tip (ICWT), 3) no-touch with ICT, and 4) no-touch with ICWT. Univariable and multivariable Cox proportional-hazards regression analyses were performed to evaluate the risk factors for LTP. The major RFA-related complications were assessed. Results: Overall, 83, 34, 80, and 14 patients were included in the ICT, ICWT, no-touch with ICT, and no-touch with ICWT groups, respectively. The cumulative LTP rates differed significantly among the four groups. Compared to tumor puncturing with ICT, tumor puncturing with ICWT was associated with a lower LTP risk (adjusted hazard ratio [aHR] = 0.11, 95% confidence interval [CI] = 0-0.88, P = 0.034). However, the cumulative LTP rate did not differ significantly between tumor-puncturing with ICT and no-touch RFA with ICT (aHR = 0.34, 95% CI = 0.03-1.62, P = 0.188) or ICWT (aHR = 0.28, 95% CI = 0-2.28, P = 0.294). An insufficient ablative margin was a risk factor for LTP (aHR = 6.13, 95% CI = 1.41-22.49, P = 0.019). The major complication rates were 1.2%, 0%, 2.5%, and 21.4% in the ICT, ICWT, no-touch with ICT, and no-touch with ICWT groups, respectively. Conclusion: ICWT was associated with a lower LTP rate compared to ICT when performing tumor-puncturing RFA. An insufficient ablation margin was a risk factor for LTP.

• Journal of Science Education
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• v.48 no.1
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• pp.47-62
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• 2024

The purpose of this study is to investigate the effects of classes using AlgeoMath on fifth grade elementary students' mathematical problem-solving skills and mathematical attitudes. For this purpose, the 'cuboid' section of the 5th grade elementary textbook based on AlgeoMath was reorganized. A total of 8 experimental classes were conducted using this teaching and learning material. And the quantitative data collected before and after the experimental lesson were statistically analyzed. In addition, by presenting instances of experimental lessons using AlgeoMath, we investigated the effectiveness and reality of classes using engineering in terms of mathematical problem-solving ability and attitude. The results of this study are as follows. First, in the mathematical problem-solving ability test, there was a significant difference between the experimental group and the comparison group at the significance level. In other words, lessons using AlgeoMath were found to be effective in increasing mathematical problem-solving skills. Second, in the mathematical attitude test, there was no significant difference between the experimental group and the comparison group at the significance level. However, the average score of the experimental group was found to be higher than that of the comparison group for all sub-elements of mathematical attitude.

• Journal of Science Education
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• v.48 no.1
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• pp.31-46
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• 2024

This study analyzes the academic achievement characteristics of Korean fourth graders on the problem solving and inquiry tasks (PSIs) introduced in TIMSS 2019. TIMSS 2019 conducted a computer-based assessment in addition to the traditional paper-based assessment. The PSIs were included only in the computer-based assessment, so 30 countries participated in the PSIs of the computer-based assessment. PSIs consist of integrating multiple content and cognitive domains, including 10 or fewer items. Most of the items are constructed in an open-ended format rather than multiple-choice. The analysis results showed that there were differences in student achievement across countries depending on the inclusion of PSIs. Korea's average achievement score decreased by 1 point. The analysis of individual items showed that students' achievement was somewhat low, and the correct answer rate for male students was generally higher than that for female students in many items. Furthermore, item-by-item analysis revealed that there were items where countries such as England and Finland had higher correct answer rates than traditional high-achieving countries, i.e. Singapore, Taiwan, and Korea. Considering the recent emphasis on integrated education, it seems necessary to review the use of PSIs in assessments in Korea as well.

• Journal of the International Relations & Interdisciplinary Education
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• v.4 no.1
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• pp.85-111
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• 2024

Since the release of the 2000 PISA results, Finland's education has consistently been regarded as a competitor or benchmark for South Korea's educational system. However, recent indicators of division, opposition, and discontent within our educational sphere suggest a considerable departure from Finland's ethos of happiness in education. Against this backdrop, this study aims to analyze the trends in Finnish education-related research appearing in Korean academic journals. Utilizing network text analysis, we examined 160 papers indexed in RISS with titles containing "Finland" and "education". Key findings are as follows. Firstly, research on Finnish education has been steadily increasing, albeit showing recent signs of decline. Secondly, the majority of research topics were micro-level, with literature review-based methodologies predominating. Thirdly, a minority of researchers accounted for one-third of the total research output. Fourthly, countries compared with Finland predominantly included neoliberal states such as Japan, the United States, the United Kingdom, Australia, and Singapore. Fifthly, research themes and subjects primarily focused on primary and secondary education, particularly in domains such as mathematics and science, influenced by PISA. Future research on Finnish education should transcend localized and fragmented areas of inquiry, undertaking comprehensive investigations into the processes and history of Finland's happiness-oriented education. Such endeavors are essential for deriving insights crucial for our learning. Particularly, consideration should be given to moving beyond literature-based methodologies, fostering international collaborative discussions facilitated online, and linking the Finnish education community with educators, parents, students, local councils, and governmental stakeholders to collectively discuss and research.

• Education of Primary School Mathematics
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• v.27 no.1
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• pp.91-110
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• 2024

The purpose of this study is to explore visual models for deriving the fractional division algorithm, to see how students understand this integrated model, the rectangular partition model, when taught in elementary school classrooms, and how they structure relationships between fractional division situations. The conclusions obtained through this study are as follows. First, in order to remind the reason for multiplying the reciprocal of the divisor or the meaning of the reciprocal, it is necessary to explain the calculation process by interpreting the fraction division formula as the context of a measurement division or the context of the determination of a unit rate. Second, the rectangular partition model can complement the detour or inappropriate parts that appear in the existing model when interpreting the fraction division formula as the context of a measurement division, and can be said to be an appropriate model for deriving the standard algorithm from the problem of the context of the inverse of a Cartesian product. Third, in the context the inverse of a Cartesian product, the rectangular partition model can naturally reveal the calculation process in the context of a measurement division and the context of the determination of a unit rate, and can show why one division formula can have two interpretations, so it can be used as an integrated model.

• Journal of the Korean Society of Radiology
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• v.83 no.1
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• pp.138-148
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• 2022

Purpose This study evaluated the rates and annual trends of pediatric CT scans in South Korea using a nationwide population-based database. Materials and Methods Data regarding pediatric CT scan usage between 2012 and 2017 were retrieved from the health insurance review and assessment service. Data on the age, sex, diagnosis, and the anatomical area of involved patients were also extracted. Results A total of 576376 CT examinations were performed among 58527528 children aged below 18 years (9.8 scans/1000 children), and the number of CT examinations per 1000 children was noted to have increased by 23.2% from 9.0 in 2012 to 11.0 in 2017. Specifically, the number of CT examinations increased by 32.9% for the 6-12 years of age group (7.4/1000 to 9.8/1000) and by 34.0% for the 13-18 years of age group (11.4/1000 to 15.3/1000). Moreover, majority of the CT scans were limited to the head (39.1%), followed by the extremities (32.5%) and the abdomen (13.7%). Notably, the number of extremity CT scans increased by 83.6% (2.3/1000 to 4.2/1000), and its proportion as compared to other scans increased from 25.3% to 37.7%. Conclusion CT scans in the pediatric population increased continuously from 2012 to 2017 at an annual rate of 4.4%. Therefore, physicians should balance the benefits of CT with its potential harms from associated radiation exposure in pediatric patients.

• Communications of Mathematical Education
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• v.38 no.2
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• pp.145-165
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• 2024

The purpose of this study is to analyze the types of errors made by Korean language learners in the use of dual numerals and provides basic data for developing an effective teaching numeration using dual numerals. To this end, a case study was conducted to analyze the types of errors that appear in numeration using dual numerals targeting Korean language learners with diverse linguistic and cultural backgrounds and different academic achievements in Korean and mathematics. Error types that categorized errors made by Korean language learners were used as an analysis framework. The conclusions obtained from the research results are as follows. First, it is necessary to provide students with opportunities to use them frequently so that they can become familiar with the use of native language numerals, which often causes errors. Second, when teaching Korean language learners with low-level Korean language academic achievement how to use Chinese numerals, it is necessary to pay attention to the multiplicative numeral system of Chinese numerals. Third, it is necessary to teach children to accurately read foreign word classifiers used with Chinese numerals accurately in Korean and distinguish between the classifiers 'o'clock' and 'hours'. There is a need to provide guidance so that native language/Chinese numerals can be used appropriately in succession along with Chinese classifiers. The results of this study may contribute to the development of an effective teaching numeration using dual numerals for Korean language learners with diverse linguistic and cultural backgrounds.

• Education of Primary School Mathematics
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• v.27 no.4
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• pp.385-403
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• 2024

The objective of this study is to examine the comprehension of third-grade students regarding the concepts of line segments, straight lines, and rays. To accomplish this, 220 students were asked to describe what each of these lines is, and the responses were subsequently analyzed. The findings of the analysis are presented as follows. Firstly, the proportion of students who accurately described the straightness of a line was 46.5% for line segments, 24.5% for straight lines, and 17.7% for rays. Secondly, 74% of all students correctly described the finiteness of line segments, whereas 33.5% and 43.8% of students accurately described the concept of infinity for straight lines and rays, respectively. Thirdly, concept images that were limited to representations of lines, such as 'straight line is a line that passes through two points' or 'straight line is a line that contains both points,' accounted for 32% of responses regarding both straight lines and rays. Additionally, other observed concept images included ambiguous representations of one line in relation to another, representations that were limited to horizontal lines, and perceptions of lines as strings. In light of these findings, I discuss the implications for the teaching and learning of line segments, straight lines, and rays.

• Education of Primary School Mathematics
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• v.27 no.4
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• pp.435-462
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• 2024

This study aims to derive educational implications for fostering mathematical creativity in elementary students. To achieve this, proportional distribution problems were presented as multiple-solution tasks, and students' problem-solving processes were analyzed from the perspective of mathematical creativity. The study involved 100 sixth-grade elementary students who were given proportional distribution problems as multiple-solution tasks to analyze their problem-solving methods. The students were grouped based on teacher variables, and the groups were assessed in terms of fluency, originality, and flexibility in mathematical creativity. The characteristics of the collective solution spaces were identified by comparing the frequency of various problem-solving strategies and representation types. The study found that teachers significantly influence mathematical creativity within collective solution spaces. Depending on the teacher, differences in fluency and originality were observed. Collective solution spaces with less reliance on formulaic approaches and higher use of diverse representations scored higher in creativity. Conversely, heavy reliance on symbolic representations was associated with lower creativity. These findings highlight the importance of encouraging various problem-solving strategies and representations within collective solution spaces to foster creativity. The study confirms that teachers play a crucial role in fostering mathematical creativity. Differences in creativity between groups based on teacher variables indicate that teachers impact students' problem-solving approaches. Additionally, relying solely on symbolic representations does not naturally lead to mathematical creativity, underscoring the need to provide students with opportunities to explore diverse mathematical representations. Creating an educational environment that encourages students to experiment with various strategies and representations is essential for nurturing their creativity.