• Journal of Korean Society of Water and Wastewater
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• v.26 no.3
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• pp.383-397
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• 2012

In this study, a System Dynamics (SD) simulation model for the efficient operations of an industrial water supply system was developed by investigating the feedback loop mechanisms involved in the operations of the system. The system was modeled so that as demand is determined the water supply quantity of intake pumping stations and dams are allocated. The main feedback loop showed that many variables such as the combinations of pump operation, unit electric power(kWh/$m^3$), unit electric power costs(won/$m^3$), water level of water way tunnel, suction pressure and discharge of pumping station, and tank and service reservoir water level had causal effects and produced results depending on their causal relationship. The configurations of the model included an intake pumping station model, water way tunnel model, pumping station model (including the tank and service reservoir water level control model), and unit electric power model. The model was verified using the data from the case study industrial water supply system that consisted of a water treatment plant, two pumping stations and four dams with an annual energy costs of 5 billion won. It was shown that the electric power costs could have been saved 7~26% during the past six years if the operations had been based on the findings of this study.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.15 no.1
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• pp.197-208
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• 2020

The firms must perform both exploitation activities that efficiently use current resources and exploration activities that capture new opportunities. A company that simultaneously performs two opposite attributes, exploitation and exploration activities, is called an 'Ambidexerity Organization' or 'Organizational ambidexterity', which is called the Ambidextrous organization. This study examines whether the key factors of entrepreneurial orientation affect a firm's performance using two-handed strategies, and empirically analyzes the moderating effects of environmental dynamics. The results show that the entrepreneurial orientation has a significant effect on a firm's performance in the Ambidextrous organization. In addition, the moderating effect of environmental dynamics showed a moderating effect on the relationship between entrepreneurial orientation and organizational ambidexterity. This study not only suggests practical implications for SMEs, including venture firms and startups, but also has a significant impact on the relationship between organizational ambidexterity and a firm's performance. It is expected to make academic contributions by introducing variables and analyzing influential relationships.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.2
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• pp.276-281
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• 2008

This paper proposes a new sliding surface which can have the same dynamics of nominal system based on SVM(Support Vector Machines). The conventional sliding mode control can not have the properties of $H_{\infty}$ controller because its sliding surface has lower order dynamics than the original system. The additional states must be used to solve this problem. However, The sliding surface of this paper can have the dynamics of $H_{\infty}$ control system by using support vector machines without defining any additional dynamic state. By using SVM, the property of $H_{\infty}$ control system can be estimated as a relationship between the states. With this relationship, a new sliding surface can be designed and have $H_{\infty}$ control system properties. As a result, in spite of the parameter uncertainty, the proposed controller can have the same dynamic of nominal system controlled by $H_{\infty}$ controller.

• Journal of Digital Convergence
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• v.16 no.8
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• pp.393-400
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• 2018

The purpose of this study was to empirically investigate the emotional dynamics among sport issues, social structure changes and collective behaviors with time-series analysis. For the purpose, the doping scandal of Tae-Hwan Park was chosen and simplified into 10 episodes. And replies and articles on them were analysed by time-series analysis. As the conclusions, first, there was a clear causal relationship between sport issue and sport emotion. Second, sport emotion was a social being which interacting with social process. Third, the sport emotional dynamics was confirmed. With this study, the sport emotion dynamics was empirically verified, but more statistical approaches would be needed for stronger evidences.

• Journal of the Korea Institute of Building Construction
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• v.11 no.3
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• pp.221-228
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• 2011

This study is on the development of a System Dynamics Model for business feasibility analysis of an apartment house development project. In this study, we analyzed other apartment development projects and research projects, and identified the cash flow items, which consist of revenue and expenditure items. In addition, we made efforts to find the influence relationship among these using the system thinking method and developed a system dynamics model. In order to test the model, a case study was conducted in which it was applied to an apartment development project. Vensim, a System Dynamics Modeling and simulation software package was used to analyze and test the model. The model suggested in this study can help a developer to make decisions on project financing at the initial stage of an apartment house development project.

• Proceedings of the Korean System Dynamics Society
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• 2002.02a
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• pp.19-40
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• 2002

The intent of this study is to develop system dynamics model for assessment of organizational and human factors in nuclear power plant which can contribute to secure the nuclear safety. Previous studies are classified into two major approaches. One is engineering approach such as ergonomics and probability safety assessment(PSA). The other is social science approach such like sociology, organization theory and psychology. Both have contributed to find organization and human factors and to present guideline to lessen human error in NPP. But, since these methodologies assume that relationship among factors is independent they don't explain the interactions among factors or variables in NPP. To overcome these limits, we have developed system dynamics model which can show cause and effect among factors and quantify organizational and human factors. The model we developed is composed of 16 functions of job process in nuclear power, and shows interactions among various factors which affects employees' productivity and job quality. Handling variables such like degree of leadership, adjustment of number of employee, and workload in each department, users can simulate various situations in nuclear power plant in the organization side. Through simulation, user can get insight to improve safety in plants and to find managerial tools in the organization and human side. Analyzing pattern of variables, users can get knowledge of their organization structure, and understand stands of other departments or employees. Ultimately they can build learning organization to secure optimal safety in nuclear power plant.

• Geomechanics and Engineering
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• v.15 no.1
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• pp.615-620
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• 2018

In order to analyze the healing effectiveness of rock salt cracks affected by the applied stresses and time, we used the ultrasonic technology to monitor the ultrasonic pulse velocity (UPV) variations for different initial stress-damaged rock salts during self-healing experiments. The self-healing experiments were to create different conditions to improve the microcracks closure or recrystallized, which the self-healing effect of damaged salt specimens were analyzed during the recovery period about 30 days. We found that: The ultrasonic pulse velocity of the damaged rock salts increases rapidly during the first 9 days recovery, and the values gradually increase to reach constant values after 30 days. The damaged value and the healed value were identified based on the variation of the wave velocity. The damaged values of the specimens that are subject to higher initial damage stress are still keeping in large after 30 days recovery under the same recovery condition It is interesting that the damage and the healing were not in the linear relationship, and there also existed a damage threshold for salt cracks healing ability. When the damage degree is less than the threshold, the self-healing ratio of rock salt is increased with the increase in damage degree. However, while the damage degree exceeds the threshold, the self-healing ratio is decreased with the increase in damage.

• Molecules and Cells
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• v.42 no.5
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• pp.418-425
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• 2019

Multicistronic elements, such as the internal ribosome entry site (IRES) and 2A-like cleavage sequence, serve crucial roles in the eukaryotic ectopic expression of exogenous genes. For utilization of multicistronic elements, the cleavage efficiency and order of elements in multicistronic vectors have been investigated; however, the dynamics of multicistronic element-mediated expression remains unclear. Here, we investigated the dynamics of encephalomyocarditis virus (EMCV) IRES- and porcine teschovirus-1 2A (p2A)-mediated expression. By utilizing real-time fluorescent imaging at a minute-level resolution, we monitored the expression of fluorescent reporters bridged by either EMCV IRES or p2A in two independent cultured cell lines, HEK293 and Neuro2a. We observed significant correlations for the two fluorescent reporters in both multicistronic elements, with a higher correlation coefficient for p2A in HEK293 but similar coefficients for IRES-mediated expression and p2A-mediated expression in Neuro2a. We further analyzed the causal relationship of multicistronic elements by convergent cross mapping (CCM). CCM revealed that in all four conditions examined, the expression of the preceding gene causally affected the dynamics of the subsequent gene. As with the cross correlation, the predictive skill of p2A was higher than that of IRES in HEK293, while the predictive skills of the two multicistronic elements were indistinguishable in Neuro2a. To summarize, we report a significant temporal correlation in both EMCV IRES- and p2A-mediated expression based on the simple bicistronic vector and real-time fluorescent monitoring. The current system also provides a valuable platform to examine the dynamic aspects of expression mediated by diverse multicistronic elements under various physiological conditions.

• Journal of Distribution Science
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• v.14 no.8
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• pp.93-100
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• 2016

Purpose - This study examines lenders' reactions to M&A, based on the strength of the lender-borrower relationship and the lender's expectations of the potential benefits or risks of the deal. Research design, data, and methodology - This research addresses the lender's influence on the implementation stage of a large-scale strategic action such as M&A to understand the motivation and dynamics of lenders' responses and empirically examines how the lender-borrower relationship influences the focal firm's merger and acquisition (M&A) transactions, using data on 501 M&A deals in Japan from 1990 to 2010. Results - The presented analysis found that lenders that have a strong lender-borrower relationship, especially those showing a high debt equity ratio, support borrowers' M&A progress and the target firm's lenders resist the deal progressing and may raise the acquisition premium if their current power relative to borrowers is weak. Conclusions - Stakeholders including lenders do not favor strategies of focal firms that threaten their future benefits, while they also tend to estimate the potential benefits and losses by comparing their current circumstances with those of other stakeholders. The empirical results of the presented analysis help explain the mechanism of lenders' reactions and offer insights into the power of a closer and stronger lender-borrower relationship.

• 한국산학경영학회:학술대회논문집
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• 2005.11a
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• pp.1-9
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• 2005

Job search research has been criticized for failing to study the dynamics and change of the job search process. A lot of previous researches have used cross-sectional designs and treated job search as a static process. As a result, job search research has failed to examine how job seekers' behaviors change during the course of their search. This paper examined changes In job search behaviors(preparatory and active job search behavior, and job search intensity) and the effects of individual difference variables(self-esteem, self-efficacy, extroversion, agreeableness, conscientiousness, openness) on job search behaviors. Data were gathered from 404 university students who had not found employment at the time of beginning of second semester The results of t-test pairs indicated that job seeking students increased their preparatory job search behavior and active job search behavior, but didn't job search intensity. The results of multiple regression showed that self-efficacy had strong relationship with preparatory and active job search behavior, and job search intensity, but self-esteem had not any relationship with them. Among big-5 personality, extroversion had relationship with active job search behavior and job search intensity, and agreeableness only with job search intensity.