• 한국수학사학회지
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• 제21권2호
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• pp.119-134
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• 2008

본 연구에서는 1709년 러시아에서 출판되었고, 다양한 작도문제의 해결방법이 기술된 '자와 컴퍼스의 방법'을 분석하였다. 이 책에 제시된 정삼각형, 정사각형, 정오각형, 정육각형, 정8각형, 정10각형의 작도방법을 소개하고, 이에 관련된 다양한 논의를 시도하였다. 이를 통해 정다각형 작도에 관련된 역사-발생적 연구를 위한 새로운 자료를 제공할 것으로 기대된다.

• 대한수학회논문집
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• 제23권1호
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• pp.29-40
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• 2008

Here, some classes of regular order semigroups are discussed. We shall consider that the problems of the existences of (multiplicative) inverse $^{\delta}po$-transversals for such classes of po-semigroups and obtain the following main results: (1) Giving the equivalent conditions of the existence of inverse $^{\delta}po$-transversals for regular order semigroups (2) showing the order orthodox semigroups with biggest inverses have necessarily a weakly multiplicative inverse $^{\delta}po$-transversal. (3) If the Green's relation $\cal{R}$ and $\cal{L}$ are strongly regular (see. sec.1), then any principally ordered regular semigroup (resp. ordered regular semigroup with biggest inverses) has necessarily a multiplicative inverse $^{\delta}po$-transversal. (4) Giving the structure theorem of principally ordered semigroups (resp. ordered regular semigroups with biggest inverses) on which $\cal{R}$ and $\cal{L}$ are strongly regular.

• 대한수학회지
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• 제45권3호
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• pp.621-630
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• 2008

In this paper, we provide a complete list of 177 equivalence classes of primitive even 2-regular quaternary positive definite quadratic forms and their discriminants. All of them have class number 1.

• Korean Journal of Mathematics
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• 제20권2호
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• pp.247-254
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• 2012

The Klee-Quaife problem is finding the minimum order ${\mu}(d,c,v)$ of the $(d,c,v)$ graph, which is a $c$-vertex connected $v$-regular graph with diameter $d$. Many authors contributed finding ${\mu}(d,c,v)$ and they also enumerated and classied the graphs in several cases. This problem is naturally extended to the case of digraphs. So we are interested in the extended Klee-Quaife problem. In this paper, we deal with an equivalent problem, finding the maximum diameter of digraphs with given order, focused on 2-regular case. We show that the maximum diameter of strongly connected 2-regular digraphs with order $n$ is $n-3$, and classify the digraphs which have diameter $n-3$. All 15 nonisomorphic extremal digraphs are listed.

• 한국학교보건학회지
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• 제3권2호
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• pp.63-87
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• 1990

The purpose of this study was to investigate the performance rate of regular health instruction by school nurses and its related factors. These data were collected by questionnaire in Mar. 1990. Total 986 school nurses who have been working primary, secondary schools in Seoul were given the questionnaire, and 672 school nurses' respectively, were finally analyzed. Analysis of the data was done utilizing SPSS/PC+for percentage, frequency, mean, $X^2$-test, t-test, ANOVA, correlation, regression. The major findings of this study were as follows : 1. Thc performance rate of regular health instruction by school nurses was 77.7% of 552 respondents. 2. The school nurses in primary school(87.0%) were more likely to perform regular health instruction than the school nurses in secondary school (63.8%). 3. The teachers of regular health instruction were more likely to display favorable attitudes toward need of health instruction. The school level was not statistically significant(P>0.05). 4. The evidence from the data analysis supported the proposition that the teachers of regular health instruction had more positive attitude toward the establishment of health subject(80.3%). The school level was statistically significant(P<0.05). 5. The school principal was a highly significant factor as it affected the performance rate of regular health instruction by school nurses. The school level was statistically significant(P<0.001). 6. The length of past career, the degree of self confidence on health instruction, the need of health instruction did affect the performance rate of regular health instruction by school nurses. On the basis of the above mentioned, so as for regular health instruction of school to be activated more throughly, regular class must be introduced in the form of establishment of health subject, enhancement of quality on the part of school nurses, made and various methods for enhancing perception toward the regular health instruction on the part of school principal are to be carried out.

• 대한수학회논문집
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• 제11권2호
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• pp.311-314
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• 1996

Let G be an abelian group of finite rink and E be the endomorphism ring of G. Then G is a left E-module by defining $f\cdota = f(a)$ for $f \in E$ and $a \in G$. In this case a condition for an E-module G to be regular is given.

• Journal of Periodontal and Implant Science
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• 제32권3호
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• pp.577-588
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• 2002

Osseointegrated implants have been established as the standard treatment modality for full/partial edentulous patients since the 1960's, and the long term results for full edentulous patients have proven to be successful. Based on these results osseointegrated implants are now widely used for partial edentulous patients. There has been an increased interest towards the efficacy of wide implants, despite many reports mentioning the lower success rate of wide implants compared to regular implants. Recently, mandibular molar area defects are commonly restored using 2 wide implants, but it is not determined whether which treatment modality-3 regular implants or 2 wide implants-shows superior success rate. In this study, 2 wide implants and 3 regular implants used for the restoration of mandibular molar area are used to compare the survival rate of 1-4 years, and to analyze and compare the failure factors. The following conclusions could be drawn from this study. 1. Wide implants and regular implants showed 94.5% and 97,6% of survival rate respectively. After prosthodontic work, the survival rate was 100% and 98.1% for wide implants and regular implants respectively. 2. 5 failed implants have been removed. 2 wide implants and 1 regular implant have been removed due to failure of osseointegration. 1 wide implant was removed due to abscess formation caused by over-heating, and 1 regular implant was removed due to mechanical failure caused by over-loading within the first year of function. 3. No statistically significant difference was observed with respect to the amount of marginal bone loss of wide and regular implants.(P>0.05) In conclusion, restoration of the mandibular molar area using 3 regular implants was found to be a good treatment modality, and 2 wide implants could he considered a good treatment modality when success factors are taken into account.

• 근관절건강학회지
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• 제24권2호
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• pp.150-158
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• 2017

Purpose: Regular physical activity is beneficial in reducing disease activity and morbidity in patients with rheumatoid arthritis (RA). The purposes of this study were to examine the levels of regular physical activity and learned helplessness and to identify factors influencing in participation in regular physical activity in RA patients. Methods: This cross-sectional study was conducted with 210 RA patients in a university-affiliated hospital. Participants completed a questionnaire including demographic and disease-related characteristics, physical activity and learned helplessness. Data were analyzed with descriptive statistics, $x^2$ tests, t-tests, and multivariate logistic regression analyses. Results: About 23% of RA patients engaged in at least 30 minutes of regular physical activity per week. Patients with being older (OR=1.09, 95%CI=1.03~1.14), no employment status (OR=0.17, 95% CI=0.07~0.42), and lower levels of learned helplessness (OR=0.58, 95% CI=0.34~0.96) had significantly higher chance of engaging in regular physical activity. Conclusion: In developing nursing interventions to promote regular physical activity in RA patients, their learned helplessness should be considered.

• 한국안전학회지
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• 제35권2호
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• pp.17-27
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• 2020

To identify the relationship between types of employment(regular and non-regular group) and departments classification (administration, product and research group) and the levels of recognition of chemical substances, a total of 117 workers in cosmetics workplaces. Mainly, regular group and research group showed higher recognition of chemical substances (PPE, ventilation, chemical management, hazards in handling chemicals, skin contact) than non-regular group and administration, product group, but In some cases, production and administrative groups were high. Descriptive statistics(SAS ver9.2)was performed. the results of recognition of chemical substances were analyzed the mean and standard deviation by t-test, and anova, (P=0.05). These results cosmetics manufacturing workplaces have normal level of the perception of chemical substances. In most of the employment types, the regular workers showed high recognition, and the working departments showed high recognition in the research and production groups. Therefore, OEM and ODM cosmetics manufacturers regularly identify characteristics and needs of workplaces and workers, and suggest the development of experience and practiced education programs and risk assessment tools that can raise worker awareness.

• Kyungpook Mathematical Journal
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• 제53권3호
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• pp.397-406
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• 2013

A ring R is called a left (right) SF-ring if simple left (right) R-modules are flat. It is still unknown whether a left (right) SF-ring is von Neumann regular. In this paper, we give some conditions for a left (right) SF-ring to be (a) von Neumann regular; (b) strongly regular; (c) division ring. It is proved that: (1) a right SF-ring R is regular if maximal essential right (left) ideals of R are weakly left (right) ideals of R (this result gives an affirmative answer to the question raised by Zhang in 1994); (2) a left SF-ring R is strongly regular if every non-zero left (right) ideal of R contains a non-zero left (right) ideal of R which is a W-ideal; (3) if R is a left SF-ring such that $l(x)(r(x))$ is an essential left (right) ideal for every right (left) zero divisor x of R, then R is a division ring.