• Journal of the Korean Operations Research and Management Science Society
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• v.24 no.3
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• pp.49-62
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• 1999

Artificial Neural Networks(ANN) have been successfully applied to various kinds of business and engineering problems, especially those involved in pattern classification. However, because of the lack of design standard or guidelines, the structure of specific ANN depends on the designer's own experiments or choices. In other words, even though we could construct a better ANN, we often steeled down with just a satisfactory ANN. The purpose of this research is to apply the Genetic Algorithm(GA) to design a structure of ANN that yields better performance compared to the existing test results. For a bankruptcy prediction problem. an exiting research using ANN which consists of 22 input processing elements(PEs) for financial ratios and 5 hidden PEs showed 70% hit ratio. In our research, the input financial ratios and the number of hidden PEs are determined by GA. The best ANN, which consists of 8 input PEs and 6 hidden PEs, shows 78.03% hit ratio. In addition, we compare the performance of two types of reproduction schemes, i.e., generational reproduction and steady-state reproduction.

• Journal of Information Technology Applications and Management
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• v.29 no.6
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• pp.95-122
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• 2022

The rapid development of technology, the spread of information, and the implementation of the government's start-up support policy exponentially increase the number of start-up companies. The purpose of this study is to investigate each company's cultural capital's effect on organization performance by promoting knowledge management activities and forming organization habitus based on Cultural Reproduction Theory and Cultural Mobility Theory. As a result of the study, it confirmed that the relationship between cultural capital, knowledge management activities, habitus, and organization performance was significant. The results of this study have academic implications as follows: First, the field of research has expanded by studying the effects of cultural capital on business administration, which is less active than existing education and sociology. Second, it accepts and supports Cultural Reproduction Theory and Cultural Mobility Theory from different perspectives.

• Journal of the Korean Mathematical Society
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• v.54 no.3
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• pp.987-997
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• 2017

A deterministic model for the spread of pine wilt disease with asymptomatic carrier trees in the host pine population is designed and rigorously analyzed. We have taken four different classes for the trees, namely susceptible, exposed, asymptomatic carrier and infected, and two different classes for the vector population, namely susceptible and infected. A complete global analysis of the model is given, which reveals that the global dynamics of the disease is completely determined by the associated basic reproduction number, denoted by $\mathcal{R}_0$. If $\mathcal{R}_0$ is less than one, the disease-free equilibrium is globally asymptotically stable, and in such a case, the endemic equilibrium does not exist. If $\mathcal{R}_0$ is greater than one, the disease persists and the unique endemic equilibrium is globally asymptotically stable.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.14 no.4
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• pp.275-284
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• 2010

Deliberate self-harm (DSH) is the act of deliberately harming your own body, such as cutting or burning yourself, without suicidal intent. It has especially become a problem among adolescents and college-age students in institutional settings such as boarding schools, Greek houses, detention centers and hospitals. We focus on contagion of DSH among adolescents and young adults by creating a deterministic epidemiological model. We study the impact of actual peer pressure, virtual peer pressure (the Internet) and treatment analytically in terms of a basic reproduction number through stability analysis of a system of ordinary differential equations. All parameters are approximated and results are also explored by simulations. The model shows that DSH is present in an endemic state in the population considered, and the control strategies are discussed.

• Korean Journal of Animal Reproduction
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• v.4 no.1
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• pp.13-19
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• 1980

This experiment was carried out to observe early morphological changes of luteal cells in Korean native cattle treated with prostaglandin F2$\alpha$. Twenty five gram of prostaglandin F2$\alpha$ was administrated per cow at 10 days after ovulation and luteal cells were removed 30, 60, 120 and 180 minites after administration. Morphological changes of each luteal cell was observed by electron microscope. the results obtained were summarized as followings: 1. Many electron-dense granules were observed in luteal cells obtained from control cow but those granules were decreased rapidly after 30 minutes of administration and no granules were obresved after 180 minutes of administration. 2. In control, the shape of mitochondria were begining to collapse from the time of 60 minutes after administration. After 180 minutes of administration, mitochondria were swelled extreamly. 3. Lipid droplets in luteal cell were increased in its size and number with the duration of time after administration. 4. Shape of smooth endoplasmic recticulum was vesicular and its dimension and number were increased according to time course after administration.

• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.36-41
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• 1986

These experiments were carried out to obtain basic information necessary for sexing embryos by chromosomal analysis. To observe metaphase chromosomes, all embryos developed to blastocysts were cultured in Ho, pp. & Pitts' medium containing 0.001% Colcemid under the gas phase of 5% CO2 in air at 37$^{\circ}C$ for 2 hours. The sex chromosome of mouse embryos shown normal development after culture in medium containing H-Y antiserum (10%, v/v) and complement (20%, v/v) also was confimed by chromosomal analysis. The results obtained in these experiments were summarized as follows: 1. Among 89 mouse blastocysts, the number of embryos identified to have XX and XY chromosome was 22(25%) and 25(28%), respectively and 42(47%) embryos were not identified. 2. Of total 40 mouse balstocysts cultured in medium containing H-Y antiserum and complement, 23(58%) embryos which were able to be discriminated their sex chromosomes were identified to be XX bearing embryos. 3. Sex chromosomes of a number of embryos subjected to chromosomal analysis were not identified. This result may be due to absence or poor quality of metaphase spreads.

• Communications of the Korean Mathematical Society
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• v.34 no.2
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• pp.685-699
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• 2019

This research is focused on a continuous epidemic model of transmission of Plasmodium vivax malaria with a time delay. The model is represented as a system of ordinary differential equations with delay. There are two equilibria, which are the disease-free state and the endemic equilibrium, depending on the basic reproduction number, $R_0$, which is calculated and decreases with the time delay. Moreover, the disease-free equilibrium is locally asymptotically stable if $R_0<1$. If $R_0>1$, a unique endemic steady state exists and is locally stable. Furthermore, Hopf bifurcation is applied to determine the conditions for periodic solutions.

• Journal of applied mathematics & informatics
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• v.41 no.1
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• pp.107-121
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• 2023

An epidemic infectious disease model consists of six compartments viz. Susceptible, Exposed, Infected, Quarantine, Recovered, and Virus with nonlinear saturation incidence rate is proposed to know the viral disease dynamics. There exist two biological equilibrium points for the model system. The system's local and global stability is done through Lyapunov's direct method about equilibrium points. The sensitivity analysis has been performed for the basic reproduction number and equilibrium points through the normalized forward sensitivity index. Sensitivity analysis shows that virus growth and quarantine rates are more sensitive parameters. In support of mathematical conclusions, numerical experimentation has been shown.

• The Pure and Applied Mathematics
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• v.30 no.2
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• pp.203-220
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• 2023

A new modification of the SIS epidemic model incorporating the adaptive host behavior is proposed. Unlike the common situation in most epidemic models, this system has two disease-free equilibrium points, and we were able to prove that as the basic reproduction number approaches the threshold of 1, these two points merge and a Bogdanov-Takens bifurcation of codimension three occurs. The occurrence of this bifurcation is a sign of the complexity of the dynamics of the system near the value 1 of basic reproduction number. Both local and global stability of disease-free and endemic equilibrium point are studied.

• Journal of applied mathematics & informatics
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• v.41 no.6
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• pp.1393-1407
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• 2023

In this study, we propose a dynamic SEIQRV mathematical model and examine it to comprehend the dynamics of COVID-19 pandemic transmission in the Coimbatore district of Tamil Nadu. Positiveness and boundedness, which are the fundamental principles of this model, have been examined and found to be reliable. The reproduction number was calculated in order to predict whether the disease would spread further. Existing arrangements of infection-free, steady states are asymptotically stable both locally and globally when R₀ < 1. The consistent state arrangements that are present in diseases are also locally steady when R₀ < 1 and globally steady when R₀ > 1. Finally, the numerical data confirms our theoretical study.