• Korean Journal of Mathematics
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• v.16 no.3
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• pp.355-362
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• 2008

We prove the existence of a unique positive solution for a class of systems of the following nonlinear suspension bridge equation with Dirichlet boundary conditions and periodic conditions $$\{{u_{tt}+u_{xxxx}+\frac{1}{4}u_{ttxx}+av^+={\phi}_{00}+{\epsilon}_1h_1(x,t)\;\;in\;(-\frac{\pi}{2},\frac{\pi}{2}){\times}R,\\{v_{tt}+v_{xxxx}+\frac{1}{4}u_{ttxx}+bu^+={\phi}_{00}+{\epsilon}_2h_2(x,t)\;\;in\;(-\frac{\pi}{2},\frac{\pi}{2}){\times}R,$$ where $u^+={\max}\{u,0\},\;{\epsilon}_1,\;{\epsilon}_2$ are small number and $h_1(x,t)$, $h_2(x,t)$ are bounded, ${\pi}$-periodic in t and even in x and t and ${\parallel} h_1{\parallel}={\parallel} h_2{\parallel}=1$. We first show that the system has a positive solution, and then prove the uniqueness by the contraction mapping principle on a Banach space

• Bulletin of the Korean Mathematical Society
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• v.57 no.3
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• pp.677-690
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• 2020

In this article, we study a reaction-diffusion system with homogeneous Dirichlet boundary conditions, which describing a three-species food chain model. Under some conditions, the predator-prey subsystem (u₁ ≡ 0) has a unique positive solution (${\bar{u_2}}$, ${\bar{u_3}}$). By using the birth rate of the prey r1 as a bifurcation parameter, a connected set of positive solutions of our system bifurcating from semi-trivial solution set (r₁, (0, ${\bar{u_2}}$, ${\bar{u_3}}$)) is obtained. Results are obtained by the use of degree theory in cones and sub and super solution techniques.

• The Journal of Information Systems
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• v.29 no.3
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• pp.53-75
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• 2020

Purpose Despite the continued rise in the popularity of mobile MMORPGs, the previous studies mainly focused on negative results of playing MMORPG such as violence and game addiction. In addition, previous studies that verified game play motives were not enough to explain user's fundamental motives for MMORPG play. To verify the positive role of playing MMORPG, this study focused on stress coping strategies on continued play MMORPG, and divided factors into two dimensions: escapism and coping with system. The purpose of this study is to comprehensively identify the discriminatory effects of each factor on users' self-control, and the effect of self-constrol and behavioral adapatation on continued use intention for MMORPG. Design/methodology/approach This study was designed to examine the structural relationships among MMORPG users' escapism, system coping, self-control, behavioral adaptation and continued use intention for MMORPG. Findings The results from this study are as follow. First, the participants' effect-based escapism had a positive impact on self-control, whereas cause-based escapism had a negative impact on self-control. Next, proactive coping and reactive coping for system problem had a positive impact on self-control. In addition, Self-control had a positive impact on behavioral adaptation and continued use intention for MMORPG. Lastly, the behavioral adaptation to MMORPG had a positive impact continued use intention. The results of our study can suggest the positive effects of coping strategy on users' self-control and behavioral adaptation by applying the theory of both escapism and coping with system. Based on our results, game companies should develop contents that can gratify users' coping motives and enhance self-control and behavioral adaptation.

• Journal of the Korea Safety Management & Science
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• v.22 no.1
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• pp.33-44
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• 2020

This study analyzed how the installation of a pressure gauge in the indoor fire hydrant of an apartment building affected identifying pressurized water in the pipe, making it easier to conduct internal inspection on the fire suppression system, and ensuring reliability of fire suppression. The following are the study's results: First, identifying pressurized water in the indoor firefighting pipe had a positive effect on the installation of a pressure gauge in the indoor fire hydrant. This implies that a higher level of identification of pressurized water in the indoor firefighting pipe had a positive impact on improving the installation and use of a pressure gauge in the indoor fire hydrant. Second, making it easier for the fire safety officer to inspect the fire suppression system had a positive effect on the installation of a pressure gauge in the indoor fire hydrant. This suggests that if it becomes easier for the apartment building's stakeholder to conduct internal inspection or the firefighting facility manager to carry out inspection on the fire suppression system, it would have a positive effect on the installation of a pressure gauge in the indoor fire hydrant. Finally, ensuring reliability in fire suppression had a positive effect on the installation of a pressure gauge in the indoor fire hydrant. This implies that if it becomes easier to identify pressurized water in the indoor firefighting pipe, for the fire safety officer to conduct internal inspection, or for the firefighting facility manager to carry out inspection in accordance with the fire suppression system's internal inspection requirements, it would increase reliability in fire suppression, making it more necessary to install a pressure gauge in the indoor fire hydrant.

• Journal of the Korean Ceramic Society
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• v.27 no.3
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• pp.337-344
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• 1990

As a function of sintering temperature and time, the electrical properties of ruthenium based thick film resistors were investigated with microstructure. The variatio of resistivity and TCR(temperature coefficient of resistance)trends of sintered speciman at various sintering temperature were different low resistivity paste(Du Pont 1721) from high one(Du Pont 1741). These phenomena are deeply relative to microstructure of sintered film. With increasing the sintering temperature for 1721 system, the electrical sheet resistivity decreased, but again gradually increased above 80$0^{\circ}C$. And TCR trends in 1721 system are all positive. On the other hand the electrical sheet resistivity of 1741 resistor system decreased with sintering temperature. And TCR trends variable according to sintering temperature. TCR of speciman sintered at $700^{\circ}C$ was negative value, and TCR of 80$0^{\circ}C$ sintered speciman coexisted negative and positive value. But in case of speciman sintered at 90$0^{\circ}C$, TCR was positive value. As results of this fact, it was well known that the charge carrier contributied to electrical conduction in 1741 resistor system varied with sintering temperature.

• Journal of Venture Innovation
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• v.4 no.2
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• pp.17-28
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• 2021

This study empirically investigates the causal relationship between healthcare accreditation system and Job Satisfaction, Service value, and organizational commitment. The results of this study can be summarized as followings. First, healthcare accreditation system had not a positive significant on the job satisfaction. Second, healthcare accreditation system had a positive significant on service value. Third, job satisfaction had a positive significant on the organizational commitment. Forth, service value had a positive significant on the organizational commitment.

• Transactions on Control, Automation and Systems Engineering
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• v.4 no.2
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• pp.140-146
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• 2002

We consider a class of large-scale interconnected time delay systems and investigate a decentralized robust passive control problem. sufficient conditions for unforced interconnected uncertain systems with time delay to be robustly stable with extended strictly passivity is given in terms of algebraic Riccati inequality and linear matrix inequality. The decentralized robust passive control problem for norm-bounded and positive real uncertainty is shown to be converted to extended strictly positive real control problem for a modified system which contains neither time delay nor uncertainty.

• Communications of the Korean Mathematical Society
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• v.32 no.1
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• pp.215-224
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• 2017

In this paper, we propose a method of order two for the computation of positive solutions to a boundary value problem of the linear beam equation. The method is based on the Power method for the eigenvector associated with the dominant eigenvalue and the Crout-like factorization algorithm for the banded system of linear equations. It is extremely fast due to the linear complexity of the linear system solver. Numerical result of a test problem is included.

• Journal of Korea Multimedia Society
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• v.24 no.9
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• pp.1299-1310
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• 2021

Under the background of the rapid development of digital educational games, we have to evidently research the elements of the achievement system of children's DEG (Digital Educational Game), and analyze the relations between the elements and make a profound study on the achievement system and its components on the impact of player's attitude. Compared with the existing research, the research contents and methods are innovative and reliable. The results show that players have a positive attitude towards the DEG achievement system, DEG achievement system has important value and role for educational games. Which is made of five elements: symbol, reward, logic, social interaction, and knowledge. The five elements interact with each other and have a positive impact on players' attitudes. DEG achievement system with five elements will bring players a positive experience. These findings provide a detailed study of the components of the achievement system. With all of these, we can explain the role and relationship of the components, and provide new ideas and empirical evidence for the design and development of children's educational game achievement system. The above findings provide a detailed description of the components of the DEG achievement system, explain the role and value of each component, and the relationships and patterns among the components, it provides a new perspective and empirical evidence for the design and development of the children's system DEG results.

• Journal of Korean society of Dental Hygiene
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• v.11 no.3
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• pp.353-361
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• 2011

Objectives : This study was to examine the social value of dental hygienists, their values about the health system and the relationship of all the related variables. Methods : The subjects in this study were 205 dental hygienists who worked in dental clinics and hospitals on Seoul. A survey was conducted from August 12 to October 15, 2010. The questionnaire consisted of nine items about general characteristics, two items about social values and 11 about values of the health system. The items related to social values and values of the health system were prepared by translating the items used in David et al's study, and the Cronbach alpha coefficient of those items respectively 0.80 and 0.76. Results : The dental hygienists got 3.94 in social values, which was above the average. In terms of values about the health care system, their values of the treatment delivery system(3.92) rated highest, followed by values of patient rights(3.79) and values of institutional restrictions(3.25). Their socal values had a closest positive correlation to their values of the treatment delivery system, and their values of patient rights had a strong positive correlation to those of the treatment delivery system and was positively correlated to those of institutional regulations as well. And there was a positive correlation between their values of the treatment delivery system and institutional regulations(r=.276). Conclusions : The above-mentioned findings illustrated that the social values of the dental hygienists had a positive correlation to their values of the health system. Therefore the kinds of educational programs that help dental hygienists to build their social values and values of the health system should be developed to improve their job efficiency as oral health experts.