• 대한수학회보
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• 제58권6호
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• pp.1387-1400
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• 2021

Suppose that $T=\(\array{A&0\\U&B}\)$ is a formal triangular matrix ring, where A and B are rings and U is a (B, A)-bimodule. Let ℭ₁ and ℭ₂ be two classes of left A-modules, 𝔇₁ and 𝔇₂ be two classes of left B-modules. We prove that (ℭ₁, ℭ₂) and (𝔇₁, 𝔇₂) are admissible balanced pairs if and only if (p(ℭ₁, 𝔇₁), h(ℭ₂, 𝔇₂) is an admissible balanced pair in T-Mod. Furthermore, we describe when ($P^{C_1}_{D_1}$, $I^{C_2}_{D_2}$) is an admissible balanced pair in T-Mod. As a consequence, we characterize when T is a left virtually Gorenstein ring.

• International Journal of Advanced Culture Technology
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• 제11권3호
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• pp.149-155
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• 2023

Since developing digital technology requires new skills in digital literacy, digital competence also has become a keystone in English classes. This study explores three aspects of English as a Foreign Language (EFL) learners' digital confidence: information and data literacy, communication and collaboration, and digital content creation, based on the European Digital Competence Framework for Citizens (DigComp). The participants were 150 Korean college students enrolled in two general English classes, and their English proficiency levels were from basic to advanced; each level consisted of 30 participants. In order to assess their digital confidence, I designed a Google survey form and collected data during two semesters. The survey results revealed that the participants had highest digital confidence in information and data literacy and overall, the female participants showed higher digital confidence than their male counterparts. It also showed that the learners' English proficiency and computer skills are important factors.

• East Asian mathematical journal
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• 제39권4호
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• pp.377-392
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• 2023

The purpose of this research was to investigate mathematics teachers' beliefs regarding the implementation of STEM approaches in secondary school mathematics classes and to identify the factors influencing their beliefs. A survey on teachers' beliefs about applying STEM in mathematics classes was developed and distributed online to mathematics teachers from middle and high schools in two metropolitan areas. Eighty-two surveys were returned from the teachers. Factor analysis revealed that the items were distributed among five main aspects. The findings indicated that most teachers believed in the necessity of implementing STEM education. However, some teachers expressed concerns about the effectiveness of implementation due to the lack of materials, resources, and equipment needed for STEM implementation.

• 대한수학회지
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• 제56권5호
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• pp.1247-1263
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• 2019

In ordered trees, two randomly chosen vertices are said to be dependent if one lies under the other. If not, we say that they are independent. We consider several classes of ordered trees with uniform updegree requirements and find the generating functions for the trees with two marked dependent/independent vertices. As a result, we compute the probability for two vertices being dependent/independent. We also count such trees by the distance between two independent vertices.

• 대한수학교육학회지:수학교육학연구
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• 제9권1호
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• pp.279-294
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• 1999

The level-based task learning had an effect on enhancing the math achievement of enrichment and ordinary classes. Besides, the analysis of mathematical attitude change showed that the level-based task learning took effect in the experimental class in every domain, including self-confidence, flexibility, will power, reaction and value, while it made little difference to the comparative class. The findings were as follows in detail. 1. The Outcome of the Achievement Test 1) The Enrichment Class In the first two tests, there were little differences in the enrichment class, But the disparity between the experimental and comparative classes became larger as this study advanced with 4.3 for the third test, 6.4 for the fourth and 6.1 for the fifth. 2) The Ordinary Class In the first to fifth achievement tests, the ordinary class made less difference than the enrichment class did. But there appeared some effect as this study progressed, since the mean grade disparity between the experimental and comparative classes was 2.1 for the first test, 3.5 for the second, 3.9 for the third, 4.4 for the fourth and 6.3 for the fifth. 3) The Supplementary Class The supplementary class showed no big difference in the first two tests. But, like the ordinary class, there was some effect with the lapse of the third 2.9 for the test, 3.2 for the fourth and 4.1 for the fifth. 2. The Change of Mathematical Attitude 1) The Experimental Class The task learning by level had a great deal of effect on the experimental class, as the pre-and post-comparative analyses showed that this class's grades were 5.1 for self-confidence, 10.8 for flexibility, 11.3 for will power, 9.7 for curiosity, 10.9 for reaction and 2.8 for value. 2) The Comparative Class The relative comparison between the comparative class and experimental class revealed that there was a hole effect on the comparative class. 3. The Outcome of Questionnaire Survey 1) They showed a positive reaction, as 40.1% of them answered the level-based task loaming served to raise their achievement, and 48.0% told so-so, and 11.9% replied they weren't helped by it. 2) The results after the experiment were;37.8% of the students say they under- stood practically everything while 12.6% of them say they under stood almost half. 3) The will to learn after the experiment shows dramatic changes between the two classes, The students in the enrichment class showed better will to learn than the students in the ordinary and supplementary classes did.

• 한국초등과학교육학회지:초등과학교육
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• 제42권4호
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• pp.591-604
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• 2023

이 연구에서는 메타버스를 활용한 초등 과학 수업이 초등학생의 학업 성취도, 과학 긍정 경험, 디지털 리터러시에 미치는 영향을 알아보고 학생들의 인식을 살펴보았다. 연구 대상은 경기도 소재 한 초등학교에서 6학년 두 개 학급으로 각각 실험집단(29명)과 비교집단(29명)으로 선정했다. '식물의 구조와 기능' 단원의 5개 차시에 대하여 실험집단은 메타버스를 활용한 과학 수업을, 비교집단은 일반적인 교과서 기반 수업을 진행하였다. 수업의 효과를 알아보기 위하여 사전 검사 점수를 공변인으로 한 공변량 분석을 실시하였고 메타버스를 활용한 과학 수업에 대한 학생들의 인식 설문 조사와 일부 대상 면담을 실시하였다. 연구 결과, 메타버스를 활용한 과학 수업은 과학 학업 성취도와 디지털 리터러시에는 유의미한 효과가 없었으며, 과학 긍정 경험의 하위 요소 중 과학 학습 정서에 대해서 통계적으로 유의미한 효과가 있는 것으로 나타났다. 메타버스를 활용한 과학 수업에 대해 학생들은 활동이 흥미롭고 다양하며 탐구 결과의 표현이 자유롭다는 측면 등에서 긍정적으로 인식하고 있었으며, 스마트기기나 네트워크 연결의 불안정성을 아쉬운 점으로 인식하였다. 이러한 연구 결과를 토대로 과학 수업에서 메타버스 활용에 대한 시사점을 논의하였다.

• 대한수학회지
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• 제49권4호
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• pp.779-794
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• 2012

In this paper, we study the global stability of two mathematical models for human immunodeficiency virus (HIV) infection with intra-cellular delays. The first model is a 5-dimensional nonlinear delay ODEs that describes the interaction of the HIV with two classes of target cells, $CD4^+$ T cells and macrophages taking into account the saturation infection rate. The second model generalizes the first one by assuming that the infection rate is given by Beddington-DeAngelis functional response. Two time delays are used to describe the time periods between viral entry the two classes of target cells and the production of new virus particles. Lyapunov functionals are constructed and LaSalle-type theorem for delay differential equation is used to establish the global asymptotic stability of the uninfected and infected steady states of the HIV infection models. We have proven that if the basic reproduction number $R_0$ is less than unity, then the uninfected steady state is globally asymptotically stable, and if the infected steady state exists, then it is globally asymptotically stable for all time delays.

• Asian Pacific Journal of Cancer Prevention
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• 제17권6호
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• pp.2871-2876
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• 2016

The Pap smear test is recommended for early diagnosis of cervical cancer. The aim of this study was to assess knowledge and behavior regarding the Pap smear test based on the Health Belief Model (HBM) in women referred to premarital counseling classes, Hamadan, Iran. This quasi-experimental study was conducted on 330 women, who were allocated randomly to two case and control groups (n=165). Two educational session classes were performed in the case group. Two stages in before and after intervention groups were evaluated. Analysis of data was performed by SPSS/16.0, using t-test, $x^2$, and McNemar's test. P-values <0.05 were regarded as significant. There was no significant difference between the mean scores of the various structures of this model in two groups before the intervention. However, after the intervention there were significant increase in mean score of knowledge and all variables of HBM in the intervention group(P<0.001). The findings of this study highlight the important role of education about cervical cancer on changing women's beliefs about cervical screening.

• 한국지진공학회논문집
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• 제20권4호
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• pp.245-256
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• 2016

In the companion paper (I - Database and Site Response Analyses), site-specific response analyses were performed at more than 300 domestic sites. In this study, a new site classification system and design response spectra are proposed using results of the site-specific response analyses. Depth to bedrock (H) and average shear wave velocity of soil above the bedrock ($V_{S,Soil}$) were adopted as parameters to classify the sites into sub-categories because these two factors mostly affect site amplification, especially for shallow bedrock region. The 20 m of depth to bedrock was selected as the initial parameter for site classification based on the trend of site coefficients obtained from the site-specific response analyses. The sites having less than 20 m of depth to bedrock (H1 sites) are sub-divided into two site classes using 260 m/s of $V_{S,Soil}$ while the sites having greater than 20 m of depth to bedrock (H2 sites) are sub-divided into two site classes at $V_{S,Soil}$ equal to 180 m/s. The integration interval of 0.4 ~ 1.5 sec period range was adopted to calculate the long-period site coefficients ($F_v$) for reflecting the amplification characteristics of Korean geological condition. In addition, the frequency distribution of depth to bedrock reported for Korean sites was also considered in calculating the site coefficients for H2 sites to incorporate sites having greater than 30 m of depth to bedrock. The relationships between the site coefficients and rock shaking intensity were proposed and then subsequently compared with the site coefficients of similar site classes suggested in other codes.

• 한국초등과학교육학회지:초등과학교육
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• 제32권1호
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• pp.71-81
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• 2013

This study aimed to investigate the changes in learner's scientific conceptual formation and academic achievement after a CoRe-based science lesson. For this study, two classes of the 6th grade of elementary school were divided into an experimental class and a comparison one. The students of the experimental class received CoRe-based science lesson and those of the comparison one received general science lesson. Both of the classes studied 'unit 1. A change in the weather', which is a part of content of 6th grade science text book. The results of this study were as follows. First, in the questions of invisible and abstract phenomena, students had misconceptions based on their experience in real life, or did not understand the fundamental causes of that phenomena. But after receiving lessons respectively, experimental class generally showed at a higher rate of understanding the causes of the phenomena than comparison class. Second, CoRe-based science lesson was more effective to improve students' scientific conceptual formation than the general science lesson. Moreover, when two classes were respectively divided into two groups as high and low-level groups according to their pre-test achievement records, the CoRe-based science lesson was more effective to learners of the high-level groups. Third, CoRe-based science lesson was more effective to enhance students' academic achievements than the general science lesson, especially to learners of the low-level groups.