• Kyungpook Mathematical Journal
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• v.61 no.1
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• pp.11-21
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• 2021

We study the structure of rings whose factor rings modulo nonzero proper ideals are right duo; such rings are called right FD. We first see that this new ring property is not left-right symmetric. We prove for a non-prime right FD ring R that R is a subdirect product of subdirectly irreducible right FD rings; and that R/N∗(R) is a subdirect product of right duo domains, and R/J(R) is a subdirect product of division rings, where N∗(R) (J(R)) is the prime (Jacobson) radical of R. We study the relation among right FD rings, division rings, commutative rings, right duo rings and simple rings, in relation to matrix rings, polynomial rings and direct products. We prove that if a ring R is right FD and 0 ≠ e2 = e ∈ R then eRe is also right FD, examining that the class of right FD rings is not closed under subrings.

• Analyses & Alternatives
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• v.4 no.2
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• pp.71-102
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• 2020

This study analyzes the effect of demographic changes on economic growth. We use the supply-side output identity to forecast the growth potential of the Korean economy. According to the results, even based on optimistic assumptions and prospects, the economic growth rate is likely to fall drastically starting in 2020. Of course, to maintain growth potential, efforts to increase productivity are necessary. However, given the historical experience of developed countries, it is not clear whether the huge trend of demographic change can be offset by efforts to increase productivity. In the so-called '30-50 club' countries, both labor productivity and growth rate tend to fall after reaching the per capita income of $30,000. The degree of decline in the growth rate is closely related to changes in the working age population and the prime-age workforce. The results are similar when tracking the path of changes in total factor productivities of the economy. When a certain level of income is reached, the increase in total factor productivity also tends to slow down. The ripple effects of rapid changes in demographics will indeed be extensive. The negative impact is likely to be concentrated at a time when the working age population, the prime-age workforce, and the total population shrink simultaneously. Above all, it is necessary to use the government's fiscal space to block the possibility of a rapid fall in the growth rate. In addition, it is important to continuously implement various reform tasks that should be promoted, such as improving the education system and strengthening the social safety net.

• East Asian mathematical journal
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• v.19 no.1
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• pp.81-89
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• 2003

There are many algorithms for factoring integers. The trial division algorithm is one of the most efficient algorithms for factoring small integers(say less than 10,000,000,000). For a number n to be factored, the runtime of the trial division algorithm depends mainly on the size of a nontrivial factor of n. In this paper, we create a function named factors that can implement the trial division algorithm in ActionScript and using the factors function we construct an interactive Prime Factorization Movie and an interactive GCD Movie.

• Bulletin of the Korean Mathematical Society
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• v.59 no.3
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• pp.781-787
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• 2022

In this paper, we show that under certain conditions the Wedderburn decomposition of a finite semisimple group algebra 𝔽_qG can be deduced from a subalgebra 𝔽_q(G/H) of factor group G/H of G, where H is a normal subgroup of G of prime order P. Here, we assume that q = p^r for some prime p and the center of each Wedderburn component of 𝔽_qG is the coefficient field 𝔽_q.

• Journal of the Korean Geosynthetics Society
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• v.16 no.2
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• pp.55-66
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• 2017

The standard piezocone penetration rate of 2 cm/s is proposed in specifications regardless of soil type. However, conditions of standard Piezo Cone Penetration (CPTU) Testings in silty soils with low plasticity vary from undrained to partially drained or fully drained penetration conditions. The partially drained shear strengths of Incheon, Hwaseong and Gunsan silty soils were estimated from the analysis results of the distributions of CPTU-based shear strengths. The CPTU-based shear strengths were compared between the undrained shear strength line and the fully drained shear strength line, which were determined from approximately ${\varphi}^{\prime}=3^{\circ}$ and ${\varphi}^{\prime}=15^{\circ}$, respectively. The internal friction angles obtained from the back analysis and UU-tests tended to increase with decreasing plasticity index, which range approximately from ${\varphi}^{\prime}=2^{\circ}$ to ${\varphi}^{\prime}=14^{\circ}$. The results matchs well with CPTU-based estimation results.

• Korea Journal of Hospital Management
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• v.19 no.1
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• pp.32-42
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• 2014

It is necessary to calculate prime cost of medical services accurately in order to evaluate the adequacy of medical fee. This paper aims to identify cost analysts' perception on prime cost of medical services and needs in establishing a cost accounting system in hospitals, proposing future directions and guidelines for the calculation of medical fee. A self-administered questionnaire and telephone survey on operation of a hospital cost-accounting system was conducted in November, 2012, among cost analysts currently working in the hospitals and hospital administrators planning to implement the hospital cost-accounting system. Our study shows that most of the cost analysts were aware of the importance of calculating prime cost and responded that collection of the prime cost data from government is necessary although they are less likely to provide the data in the future concerning the risk of data misuse and data security. They also responded that lack of budget allocation and excessive workload were the main reasons for not estimating the prime cost and operating cost management information system. Results show that hospital cost analysts considered the data accuracy is the most critical factor in calculating prime costs of medical services. However, there was no investment budget allocated in some hospitals or limited to less than 100 million, indicating that hospitals are reluctant to invest on implementing the cost accounting system. Respondents stated the organization that collects the prime cost of medical services among hospitals should display strong analytical capabilities, ensure data security, and maintain independence, which is most demanded. There are 57 hospitals that calculated the prime cost of medical services for 2012 by each medical department and 20 hospitals that calculated the prime cost by fee-for-services, aiming to establish a cost accounting system. Our results indicate that hospitals should voluntarily provide the accurate prime cost for medical services in order to properly evaluate the adequacy of medical fee. Consequently, it is critical to establish an independent organization to collect and appraise the data. It is also recommended that government should implement various policies to encourage hospitals to participate in the data collection to achieve the data accuracy and representativeness.

• Bulletin of the Korean Mathematical Society
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• v.38 no.3
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• pp.475-486
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• 2001

In this paper we give a relationship among the Minkowski units, for all odd prime number including $\infty$, of 2-periodic knot is $S^3$, its factor knot, and the 2-component link consisting of the factor knot and the set of fixed points of the periodic action.

• Korean Journal of Mathematics
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• v.26 no.3
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• pp.459-465
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• 2018

Recently, Li et al proved that ${\Phi}$ which satisfies the following condition on factor von Neumann algebras $${\Phi}([[A,B]_*,C]_*)=[[{\Phi}(A),B]_*,C]_*+[[A,{\Phi}(B)]_*,C]_*+[[A,B]_*,{\Phi}(C)]_*$$ where $[A,B]_*=AB-BA^*$ for all $A,B{\in}{\mathcal{A}}$, is additive ${\ast}-derivation$. In this short note we show the additivity of ${\Phi}$ which satisfies the above condition on prime ${\ast}-algebras$.

• Journal of the Korean housing association
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• v.14 no.4
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• pp.49-56
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• 2003

The object of this study is to analyze the influential factors of characteristics of residential locations by age, and to offer a groundwork that can be utilized to direct setting of residential development and housing policies. The main findings are drawn as follows: First, it determines the age groupings which can describe the distribution pattern of residential location, which is broken down into two social subgroups - the older group aged 50 and over, and the younger group, being our educational target. Second, actuality of our education is to influence residential location. Third, four groups that can describe residential location are abstracted. Fourth, the prime of manhood and old age prime of life have been superior within inner zone, while middle age and those who are obliged to support the older group have been superior around the outer zone.

• Journal of Communications and Networks
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• v.13 no.5
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• pp.449-455
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• 2011

Inspired by fast Jacket transforms, we propose simple factorization and construction algorithms for the M-dimensional discrete Fourier transform (DFT) matrices underlying generalized Chinese remainder theorem (CRT) index mappings. Based on successive coprime-order DFT matrices with respect to the CRT with recursive relations, the proposed algorithms are presented with simplicity and clarity on the basis of the yielded sparse matrices. The results indicate that our algorithms compare favorably with the direct-computation approach.