• Journal of the Korean Society of Systems Engineering
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• v.19 no.1
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• pp.14-28
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• 2023

The spin-off where the principal technology developers take the lead in the active and initiative pursuit of the commercialization of technologies is increasingly drawing attention, breaking away from the traditional means through the technology transfer or licensing of the public technologies created by the developers. This study aimed to determine the reasons for such differences from the perspective of the institutional theory. The results show that only the start-up support system, profit distribution system for researchers, degree of participation in the technology marketing, entrepreneurship of researchers, the use of start-up systems affected the number of start-ups of spin-off companies. Furthermore, an analysis of success factors and a study on the exploration of success paths for the RSOs will also be required

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.6
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• pp.159-168
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• 2007

The problem of determination of axial force in continuous welded rail(CWR) has attracted a number of railroad engineers due to its practical importance in prevention of accidents related to buckling and pull apart. In this paper, we investigated the application of the beam-column theory to presume the axial force in CWR and proposed the development process of the prediction equation and model to presume the axial force in CWR.

• Korean Journal of Mathematics
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• v.28 no.2
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• pp.379-389
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• 2020

An r-color Rado number N = R(𝓛, r) for a system 𝓛 of equations is the least integer, provided it exists, such that for every r-coloring of the set {1, 2, …, N}, there is a monochromatic solution to 𝓛. In this paper, we study the 2-color Rado number R(𝓔, 2) for 𝓔 : x₁ + x₂ + ⋯ + x_n = y₁ + y₂ = z when n ≥ 4.

• Proceedings of the KIEE Conference
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• 1993.07a
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• pp.489-491
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• 1993

Many optimization problem or multiple attribute, multiple alternative decision making problem may have fuzzy evaluation factors. In this case, fuzzy number operation technique is needed to evaluate and compare object functions which become fuzzy sets. Generally, fuzzy number operations can be defined by extension principle of fuzzy set theory, but it is tedious to do fuzzy number operations by using extension principle when the membership functions are defined by complex functions. Many fast methods which approximate the membership functions such as triangle, trapezoidal, or L-R type functions are proposed. In this paper, a fast fuzzy number operation method is proposed which do not simplify the membership functions of fuzzy numbers.

• Bulletin of the Korean Chemical Society
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• v.22 no.8
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• pp.827-832
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• 2001

The excitation temperature and electron number density have been measured for end-on-view ICP discharge. In this work, end-on-view ICP-AES equipped with the newly developed “optical plasma interface (OPI)” was used to eliminate or remove the neg ative effects caused by end-on-plasma source. The axial excitation temperature was measured using analyte (Fe I) emission line data obtained with end-on-view ICP-AES. The axial electron number density was calculated by Saha-Eggert ionization equilibrium theory. In the present study, the effects of forward power, nebulizer gas flow rate and the presence of Na on the excitation temperature and electron number density have been investigated. For sample introduction, two kinds of nebulizers (pneumatic and ultrasonic nebulizer) were utilized.

• Korean Journal of Environment and Ecology
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• v.32 no.5
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• pp.497-506
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• 2018

The purpose of this study was to investigate the proper minimum viable population of a seed bank for the ecological restoration of pine forest using a seed bank. It examined the germinated soil seed bank from August 2010 to November 2011. The results of the correlation analysis showed that the area and the number of herbaceous species were the highest at 0.686. The results of the regression analysis of four variables including the number of woody species, the number of woody individuals, the number of herbaceous species, and the number of herbaceous individuals using the theory of island biogeography to the minimum viable population in studied plots showed that all four variables were significant with area at the level of 0.05, and R square was 0.583. One function was selected between the number of species and the number of individuals from the canonical correlation analysis, and the function square was 0.824. Both canonical function and squared canonical correlation showed significant at the level of 0.01. The result of study recommended the area size of the minimum viable population in pine forest applied by seed bank to be larger than $64m^2$, the number of species to be over 21, and the number of population to be over 120. It also found that the number of herbaceous species determined the cluster size of the seed bank. Therefore, it is necessary to consider herbaceous species that appear in the seed bank.

• Korean Journal of Cognitive Science
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• v.24 no.3
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• pp.271-300
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• 2013

Human and animals are born with an intuitive ability to determine approximate numerosity. This ability is termed approximate number sense (hereafter, number sense). Evolutionarily, number sense is thought to be an essential ability for hunting, gathering and survival. According to previous research, children with mathematical learning disability have impaired number sense. On the other hand, individuals with more accurate number sense have higher mathematical achievement. These results support the hypothesis that number sense provides a basis for the development of mathematical cognition. Recently, researchers have been examining whether number sense training can lead to enhancement in mathematical achievement and changes in brain activity in relation to mathematical problem solving. Numerosity which basically represents discontinuous quantity is expected to be closely related to continuous quantity such as representations of space and time. A theory of magnitude (ATOM) states that processing of number, space and time is based on a common magnitude system in the posterior parietal cortex, especially the intraparietal sulcus. The present paper introduces current literature and future directions for the study of the common magnitude system.

• Korean Journal of Environment and Ecology
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• v.12 no.2
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• pp.147-155
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• 1998

This study was conducted from March to August 1997 to decide the size of plant community in fragmentary habitats. The thirty one sites and one hundred and eighteen plots were plotted in the areas including Yangpyong, Yoju, Pyongtaek and Ansong in Kyonggi-do, Chomchon and Sangju in Kyongsangbuk-do, Nonsan in Chungchongnam-do and Iksan in Chollapuk-do. The area and number of woody species by correlation analysis were recorded as the highest value as 0.716. In order to apply the theory of island biogeography to the fragmented habitats in Korea, the four variables were calculated by regression model. The four variables such as number of woody species, number of woody individuals, number of herbaceous species and number of herbaceous individuals were recorded as significant with area at the level of 0.05 and R square was 0.71. The one function was selected between number of species and number of individuals from the canonical correlation analysis, and the function square was 0.8876. Both canonical function and squared canonical correlation showed significant at the level of 0.01. The number of species and individuals were not increased from the condition that was the size of plant community of 400$m^2$, 30 for number of species and 4,000 for number of individuals. This results of this study can be widely used as a basic information for the conservation management, especially the fragmented ecosystems or the biotop creation in the landscaping.

• Journal of Korean Society for Quality Management
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• v.48 no.1
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• pp.201-214
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• 2020

Purpose: The purpose of this paper is to determine an optimal number of cycle times for the replacement under the circumstance where the system is replaced at the periodic time and the multiple number of working cycles whichever occurs first and the system is minimally repaired between the replacements if it fails. Methods: The system is replaced at periodic time () or cycle time, whichever occurs first, and is repaired minimally when it fails between successive replacements. To determine the optimal number of cycle times, the expected total cost rate is optimized with respect to the number of cycle times, where the expected total cost rate is defined as the ratio of the expected total cost between replacements to the expected time between replacements. Results: In this paper, we conduct a sensitivity analysis to find the following results. First, when the expected number of failures per unit time increases, the optimal number of cycle times decreases. Second, when the periodic time for replacement becomes longer, the optimal number of cycle times decreases. Third, when the expected value for exponential distribution of the cycle time increases, the optimal number of cycle times increases. Conclusion: A mathematical model is suggested to find the optimal number of cycle times and numerical examples are provided through the sensitivity analysis on the model parameters to see the patterns for changes of the optimal number of cycle times.

• Journal of applied mathematics & informatics
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• v.17 no.1_2_3
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• pp.401-418
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• 2005

In this paper, a dual algorithm, based on a smoothing function of Bertsekas (1982), is established for solving unconstrained minimax problems. It is proven that a sequence of points, generated by solving a sequence of unconstrained minimizers of the smoothing function with changing parameter t, converges with Q-superlinear rate to a Kuhn-Thcker point locally under some mild conditions. The relationship between the condition number of the Hessian matrix of the smoothing function and the parameter is studied, which also validates the convergence theory. Finally the numerical results are reported to show the effectiveness of this algorithm.