• The Mathematical Education
• /
• v.46 no.3
• /
• pp.303-314
• /
• 2007

In this paper we try to study a method of constructing plane sections of regular tetrahedron and regular hexahedron. In order to construct plane sections of regular tetrahedron and regular hexahedron first of all, we extract some base problems that are used for construction. And we describe construction process using base problems in detail.

• Korean Journal of Mathematics
• /
• v.10 no.2
• /
• pp.117-122
• /
• 2002

In this paper, we give some properties of left(right) semi-regular and $g$-regular $po$-semigroups.

• Journal of Labour Economics
• /
• v.30 no.2
• /
• pp.1-31
• /
• 2007

The purpose of this paper is to analyse wage differentials between non-regular and regular works. Data from EAPS(Economically Active Population Survey) 2005 show that the monthly wage level of non-regular worker is only 63% of regular worker and thus there exist 37% wage differentials. However, these wage differentials do not control for hours of work, the amount of human capital, job characteristics, and other individual characteristics affecting wages. If these variables are added to the hourly wage regression equation, the wage gap between non-regular and regular workers drastically decreases to 2.2%. Furthermore, decomposition of the wage differentials by Oaxaca method shows that productivity difference between non-regular and regular workers explains up to 91% of the wage gap. This implies that the magnitude of wage discrimination against non-regular workers is at most 0.2% of hourly wage of regular workers. To control for unobserved individual heterogeneities more accurately, we also construct panel data and estimate wage differentials. The results from the panel data approach show that there is no difference in the hourly wages between non-regular and regular workers. In some specifications, the wage rate of non-regular worker is rather higher than that of regular worker. These results are consistent with economic theory. Other things being equal, workers with unstable employment may require higher wages to compensate their unstability. Firms are willing to pay higher wages if they can get more flexibility from non-regular employment. Empirical results in this paper cast doubt on the view that there is wage discrimination against non-regular workers in the labor market. Public policies should be targeted for disadvantaged groups among non-regular workers, not for non-regular workers in general.

• Korean Journal of Mathematics
• /
• v.9 no.2
• /
• pp.99-104
• /
• 2001

We give the characterization of left(right) semi-regular $po$-semigroups and $Ve$-semigroups.

• Journal of the Chungcheong Mathematical Society
• /
• v.19 no.4
• /
• pp.365-373
• /
• 2006

In this paper four regular relations, R, $L^*$, $M^*$ and $Q^*$ in a transformation group (X, T) are defined and some of their properties are studied.

• Journal of Labour Economics
• /
• v.43 no.3
• /
• pp.33-61
• /
• 2020

The purpose of this study is to analyze the disparity in on-the-job training between regular and non-regular workers and to compare the wage effects of on-the-job training. Using the Korean micro data from the Programme for the International Assessment of Adult Competencies(PIAAC) published by OECD, Propensity Score Method(PSM) is applied to overcome the endogeneity problem. The average treatment effect(ATT) on the training participation is analyzed, using non-regular workers as treatment group and regular workers as comparison group. Odds ratios of non-regular employees' training participation compared to regular employees shows 0.67 times after constructing matching sample and this means that non-regular workers are facing a disadvantageous training opportunity compared to regular workers. In order to estimate the wage effect of on-the-job training, the average treatment effect(ATT) of on-the-job training on average wages for regular workers and non-regular workers is estimated respectively. I find insignificant wage effect from on-the-job training among regular workers and significant positive effect on non-regular worker's wage from on-the-job training.

• The Pure and Applied Mathematics
• /
• v.17 no.2
• /
• pp.131-136
• /
• 2010

Throught this paper, we will investigate some properties of left regular and strongly reduced near-rings. Mason introduced the notion of left regularity and he characterized left regular zero-symmetric unital near-rings. Also, this concept have been studied by several authors. The purpose of this paper is to find some characterizations of the strong reducibility in near-rings, and the strong regularity in near-rings which are closely related with strongly reduced near-rings.

• Bulletin of the Korean Mathematical Society
• /
• v.59 no.1
• /
• pp.213-226
• /
• 2022

Let R be a ring and M an R-module. Then M is said to be regular w-flat provided that the natural homomorphism I ⊗_R M → R ⊗_R M is a w-monomorphism for any regular ideal I. We distinguish regular w-flat modules from regular flat modules and w-flat modules by idealization constructions. Then we give some characterizations of total quotient rings and Prüfer v-multiplication rings (PvMRs for short) utilizing the homological properties of regular w-flat modules.

• Journal of the Korean Society of Safety
• /
• v.22 no.4
• /
• pp.83-89
• /
• 2007

This study is perform to improve the current point at issue of the non-regular employees, comparing the safety and health consciousness of between the regular employees and non-regular employees in manufacturing factory. The investigation is carried out using the statistical analysis. The study presents that most of the non-regular employees answer in the negative the current job satisfaction, work load, work risk, concern on the safety and health, education, occupational safety and health system than the regular employees. For the improvement of these problems, the government's safety and health policy should be changed and acknowledgement of the employer and employee on the safety and health should be improved.

• Journal for History of Mathematics
• /
• v.21 no.2
• /
• pp.119-134
• /
• 2008

In this paper we study a book 'Method of Ruler and Compass' written in Russia three hundreds years ago. In this book many construction problems related with plane figures and solid figures are solved. In this study we analyze construction method of some regular polygon(square, regular pentagon, regular octagon, regular decagon) suggested in 'Method of Ruler and Compass', give mathematical proofs of these construction.