• Journal of the Korean Data and Information Science Society
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• v.25 no.3
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• pp.623-632
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• 2014

We shall consider the estimation for the parameter and the right tail probability in a general exponential distribution. We also shall consider the estimation of the reliability P(X < Y ) and the skewness trends of the density function of the ratio X=(X+Y) for two independent general exponential variables each having different shape parameters and known scale parameter. We then shall consider the estimation of the failure rate average and the hazard function for a general exponential variable having the density function with the unknown shape and known scale parameters, and for a bivariate density induced by the general exponential density.

• Korean Management Science Review
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• v.13 no.2
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• pp.1-11
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• 1996

Two different methods to extract the license plate area of a vehicle have been used for automatic recognition purposes. One method is with a color vision system and the other is with an edge detecting operator. The system with color vision has some problems if the colors of license plate and vehicle's body are similar. The various plate colors in Korea also drops the system performance. The edge detecting operator also has a problem for a real time processing since it performs on all pixels of the scene. In this paper a possible method using gray level vision system and available pre-known information of license plates is suggested. The suggested procedure searches the lower boundary of the plate by counting high contrast points between one and near pixel from the bottom line of the scene. It finds the upper boundary from the bottom line by adding number plate height after finding the lower boundary. The left and right boundaries are found by similar processes.

• The Pure and Applied Mathematics
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• v.6 no.2
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• pp.121-127
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• 1999

We can get the Pascal's matrix of order n by taking the first n rows of Pascal's triangle and filling in with 0's on the right. In this paper we obtain some well known combinatorial identities and a factorization of the Stirling matrix from the Pascal's matrix.

• Kyungpook Mathematical Journal
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• v.56 no.3
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• pp.861-866
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• 2016

A ring R called left SF if its simple left modules are at. Regular rings are known to be left SF-rings. However, till date it is unknown whether a left SF-ring is necessarily regular. In this paper, we prove the strong regularity of left (right) complement bounded left SF-rings. We also prove the strong regularity of a class of generalized semi-commutative left SF-rings.

• Journal of the Korean Mathematical Society
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• v.46 no.1
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• pp.51-58
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• 2009

Let R be a ring. A right R-module M is called perfect if M possesses a projective cover. In this paper, we consider the relationship between the class of perfect modules and other classes of modules. Some known rings are characterized by these relationships.

• Journal of the Korean housing association
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• v.15 no.3
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• pp.101-108
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• 2004

To find more efficient exhaust effect, air curtain of upward or downward trend in gas table and left or right side of range hood were made. As result that film vapor from range hood lower part by digital camera, the air current change by moving existence and nonexistence of exhaust fan and direction of air curtain were known. Under all experiment condition, upward air curtain superior exhaust performance.

• The Korean Journal of Nuclear Medicine
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• v.20 no.1
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• pp.85-91
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• 1986

In detecting, localizing and quantitating cardiac shunts, radionulide angiocardiography has been known to be a simple and safe method compared with oxymetry method. To ascertain the availability of the results obtained by radionuclide angiocardiography for the evaluation of patients with cardiac shunt, author compared the Qp/Qs ratios(pulmonary to systemic flow ratios) obtained by radionuclide angiocardiography with the results of oximetry method in 40 patients with left to right shunt, and also compared the results of radionuclide angiocardiography examined before and after shunt operation in 8 patients. The results were as follows: 1) Of the 161 patients examined radionuclide angiocardiography, 98 were thought to have cardiac shunts: right to left shunt id 27, left to right shunt in 71. Of the 71 patients who had left to right shunt, 40 who were examined with both radionuclide angiocardiography and oxymetry had following congenital heart disease: VSD in 21, ASD in 9 and PDA in 10. 2) Comparison of Qp/Qs ratios obtained during radionuclide angiocardiography and oxymetry revealed good correlation (linear regression analysis yielded correlation coefficient of 0.80) in 32 patients whose Qp/Qs ratio obtained during oxymetry were below 3.0, but very poor correlation in 8 patients whose Qp/Qs ratios were above 3.0 3) Radionuclide angiocardiography is a relatively safe and simple method in postoperative evaluation of patients with cardiac shunt.

• Journal of the Korean Mathematical Society
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• v.54 no.4
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• pp.1281-1299
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• 2017

A submodule N of a module M is called ${\mathcal{S}}$-closed (in M) if M/N is nonsingular. It is well-known that the class Closed of short exact sequences determined by closed submodules is a proper class in the sense of Buchsbaum. However, the class $\mathcal{S}-Closed$ of short exact sequences determined by $\mathcal{S}$-closed submodules need not be a proper class. In the first part of the paper, we describe the smallest proper class ${\langle}\mathcal{S-Closed}{\rangle}$ containing $\mathcal{S-Closed}$ in terms of $\mathcal{S}$-closed submodules. We show that this class coincides with the proper classes projectively generated by Goldie torsion modules and coprojectively generated by nonsingular modules. Moreover, for a right nonsingular ring R, it coincides with the proper class generated by neat submodules if and only if R is a right SI-ring. In abelian groups, the elements of this class are exactly torsionsplitting. In the second part, coprojective modules of this class which we call ec-flat modules are also investigated. We prove that injective modules are ec-flat if and only if each injective hull of a Goldie torsion module is projective if and only if every Goldie torsion module embeds in a projective module. For a left Noetherian right nonsingular ring R of which the identity element is a sum of orthogonal primitive idempotents, we prove that the class ${\langle}\mathcal{S-Closed}{\rangle}$ coincides with the class of pure-exact sequences of modules if and only if R is a two-sided hereditary, two-sided $\mathcal{CS}$-ring and every singular right module is a direct sum of finitely presented modules.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.1
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• pp.9-25
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• 2014

It is very important to select the best employees who are suitable for their jobs and duties as considering the efficiency and productivity of the firms' performance. As a result, many kinds of selection methodologies and systems have been developed. Among them is the selection system based on the core competencies which is known as the superior selection systems that can increase the predictive validity who is the right people, compared to the traditional selection system based on the job analysis. Hence, the former has been focused in the complex business situation in recent years. In this case study, we examine the selection system case based on the core competencies of OSS team in Company A, which is one of the largest telecommunication firms and we suggest the implications. According to the results of this case study, defining the core competencies of the job and selecting the right people who had the related competencies not only decreased the turnover rate of OSS team in Company A, but also increased the employees' loyalty and satisfaction for the organizations. This study will be a benchmark to other departments that don't use competency selection system of Company A as well as the firms that want to adapt the selection system based on the core competencies. Also, this case study has a contribution that shows us an alternative model how can the firms identify and select the best right employees.

• Journal of Digital Contents Society
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• v.18 no.2
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• pp.239-247
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• 2017

In the past, delivering knowledge mainly, education focused on the development of left brain. However, as the importance of right brain is widely accepted, various approaches on education in creativity have been tried. With the advance in the research on the brain, it has been known that the left brain and the right brain are closely linked to work effectively while they are specialized to some functionalities differently. We developed an educational content exploiting Chinese characters to facilitate the balanced development of both brain. Making categorizations from Yin-yang and five elements of the universe, it consists of four stages. The first stage is to stimulate the brain with visual scandal. The second one, third one, and the fourth one are to develop the right brain, left brain, and both brain respectively. Through expert interview, the potential of the developed content as an efficacious method for brain development was verified.