• Korean System Dynamics Review
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• v.17 no.1
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• pp.25-40
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• 2016

This research aims to identify important variables and their effects on diabetes prevention or progression from prediabetes to diabetic complication using system thinking. Based on the existing studies, we have constructed a causal loop diagram explaining dynamics of diabetes and have found 7 important reinforcing loops and 3 balancing loops in the causal loop diagram. The CLD displays an effect of increasing prediabetes early detection and awareness on diabetes prevention. The findings indicate that the projects in Korea for reducing incidence of diabetes and potential risk of complication have focused on variables which are related only on diabetes even though prediabetes has been a critical point on diabetes prevention and management. Thus, it also concludes that the effect of projects focusing only on diabetes have faced limitation to manage diabetes accordingly.

• Korean System Dynamics Review
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• v.8 no.1
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• pp.211-227
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• 2007

Like the saying "You can't manage what you can't measure," performance measurement is considered as one of the most important management activities for the organizations in either private or public sector. Performance measurement, however, has thus far relied too much on financial statements. Realizing the importance of a more scientific and comprehensive performance measurement, many organizations have adopted several different systems in order to objectively estimate their balanced performance results. The Balanced Scorecard (BSC) has become a popular means to measure performance. But the BSC has also received some criticisms. In this paper four limitations in the use of the BSC are discussed : BSCs focus on unidirectional causality, are unable to distinguish delays between actions and their impacts on performance, integrate insufficiently strategy with operational measures, and lead to internal biases. We propose a system dynamics approach with causal loop diagram(CLD) to develop a Dynamic BSC in order to overcome these limitations. The results suggest that developing a BSC with system dynamics is a promising approach to supplement existing BSC frameworks.

• Korean System Dynamics Review
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• v.15 no.2
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• pp.97-131
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• 2014

The purpose of this study is to analyze Foreign Exchange(FX) exposure and FX hedge strategy based on the systems thinking perspective using causal loop diagrams. FX exposure has been a critical issue on a business management. Many studies in Korea have researches on variables which make effects to the company value. This study displays causal loop diagrams(CLDs) on these issues. In order to make CLD more objective, most causalities are articulated from recent 72 studies (1998~2013) of domestic top journals. This approach is valuable in that it is the first try to draw all the causalities from various literature review regarding FX exposure and FX hedge strategy. This study is expected to make a useful and basic material to research the financial issues of corporate, as the first research to dynamically understand FX exposure and FX hedge strategy.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.5
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• pp.23-28
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• 2002

As the interest on the air pollution is gradually rising up at home and abroad, automotive industries have been working on the exhaust emission reduction from vehicles through a lot of approaches, which consist of new engine design, innovative aftertreatment systems, and using clean fuels. Methanol, ethanol, LNG, LPG, H2, reformulated gasoline are generally recognized as the clean fuel. Since the low price policy of government on LPG has expanded its vehicle market recently, there is concern of the exhaust emission of LPG vehicle. In this paper, we studied the value of LPG fuel as a clean fuel by comparing the results of the exhaust emission from LPG and Gasoline fueled vehicles, and discussed its limitation of LPG vehicle with mixer type as a fuel supply system. FTIR was used to understand the difference of exhaust emission components of LPG and Gasoline fueled vehicles.

• Korean System Dynamics Review
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• v.15 no.4
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• pp.29-60
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• 2014

As every commentators has noted, bureaucratic corruption, which has complicated causes, is prevalent phenomenon in Korean society. Especially, most people realize that systemic corruption has a strong negative effect on society; however, only few studies reflect on the nature of 'systemic corruption' and it seems that no established theory explains the phenomenon. Thus, this study suggest that we look more carefully into the nature and mechanisms of 'systemic corruption'. Interdisciplinary approach based on the integrated model of structure-behavior to analyse the nature of bureaucratic corruption. The system dynamics method can test the mechanisms of 'systemic corruption'. With this way, the factors generating systemic corruption represent the relationships reinforcing and balancing within system dynamics model. This paper also consider 'isomorphism' and 'dominance' as control mechanisms to systemic corruption. From the CLD(Causal Loop Diagram), three main areas(rent in organization, networking, control mechanisms) are overlapped and it indicates dynamic relationships of systemic corruption in organizations.

• Korean System Dynamics Review
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• v.12 no.1
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• pp.89-114
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• 2011

With steady increase in the demand for door-to-door delivery services, courier service providers are facing a constant pressure to reduce delivery price in order to secure quantity order and to improve the efficiency and reliability for customer service. The objective of this research is to explain the structure of the door-to-door delivery including door-to-door delivery service demand, sorting capacity in the hub-terminal, and the system performance measures such as service reliability networks using causal loop diagram(CLD). Based on causal relation, this research describes a comprehensive approach to examine how capacity reliability contributes to the renewal of the firm's competences through its reciprocal relationship with travel time reliability and connectivity reliability. Also, this research suggests the policy alternatives to improve effectiveness and efficiency of door-to-door delivery network in response to increase customer satisfaction and profit maximization of the courier service providers: operational, tactical, and strategic levels.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.181-187
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• 2005

The behavior of fox adsorption and desorption of the NOx storage catalyst supported on Ba additive were studied by the TPA/TPD experiments and reactivity tests. Applying the transient responses and NOx TPA/TPD test by CLD were effective methods to analyze the characteristics of the NOx storage catalyst. NOx variation of the NOx storage catalyst in the lean air/fuel conditions according to temperature was dominated by NOx adsorption and desorption rather than catalytic reduction. The presence of reductants in the lean mixture promoted the NOx desorption at the $500^{\circ}C$ higher temperature. The temperatures for maximum NOx conversion with CH4 and $C_3H_6$ as a rich spike reductant appear around $500^{\circ}C\;and\; 400^{\circ}C$ respectively.

• Korean System Dynamics Review
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• v.9 no.1
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• pp.33-56
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• 2008

With emphasis on the importance of systems thinking for the establishment of learning organization, Senge in his famous book "The Fifth Discipline", explains in depth four disciplines such as personal mastery, mental models, shared vision, team learning, which are all geared up to the implementation of learning organization. However, two critical pitfalls are found: First, a holistic picture is absent in his presentation of learning organization, which just seems like a puzzle with linking pieces missing between disciplines. Secondly, as is often the case too much details are discussed in expense of insights on each discipline. This paper thus attempts to draw core metaphysical insights underlying Senge's learning organization disciplines by reinterpreting them from oriental perspectives; and to identify mechanisms depicting how they are working together as a whole, which is enabled by exploiting causal loop diagrams as a tool of systems thinking. In addition some thoughts on the implications of systems thinking on each of the learning organization disciplines.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.3108-3113
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• 2008

This paper investigated the behaviors of combustion characteristics at part load condition with various intake charge motions induced by the port masking schemes in the CVVT (Continuously Variable valve Timing) engine. Time resolved in-cylinder and exhaust emissions were measured by the fast response HC and NOx analyzers to examine their formation mechanisms and behavior characteristics. As a result, in-cylinder HC decreased with the advanced intake valve timings but HC at the exhaust port increased due to the worse combustion stabilities. However HC reduction could be achieved by the application of the port maskings with a enhancement of the engine stability. NOx also decreased with early intake timings by internal EGR but increased with the charge motion controls which enhance the combustion behavior.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.58-58
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• 2000

Recently low resistance of bus line is required for large screen size RFT-CLD panels. As a result, lower resistance Al-alloy is currently reviewed extensively. The resistivity is required smaller than 10$\mu$$\Omega$cm and high resistance of chemical attack is required. In this paper, Al-W thin film were deposited on glass substrates by D.C magnetron sputtering system under various condition for high chemical resistance. Its properties were characterized by SEM, AFM, XRD, 4-point-probe, and cyclic voltammertry. The optimal condition of Al-W was 10$0^{\circ}C$, 100W, 0.4Pa, 23sccm(Ar) and 35$0^{\circ}C$, 20min. annealing. At that condition the resistivity of Al-W(3 wt.%) was about 11$\mu$$\Omega$cm. And when wt.% of W in Al-W alloy was higher than about 4%, Al-W alloy thin film has high chemical resistance.