• Title, Summary, Keyword: Dynamics

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Determination of Proper Time Step for Molecular Dynamics Simulation

  • Jo, Jong Cheol;Kim, Byeong Cheol
    • Bulletin of the Korean Chemical Society
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    • v.21 no.4
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    • pp.419-424
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    • 2000
  • In this study we have investigated the determination of proper time step in molecular dynamics simulation.Since the molecular dynamics is mathematically related to nonlinear dynamics, the analysis of eigenvalues isused to explain the relationship between the time step and dynamics. The tracings of H2 and CO2 molecular dynamics simulation agrees very well with the analytical solutions. For H2, the time step less than 1.823 fs pro-vides stable dynamics. ForCO2, 3.808 fs might be the maximum time step for proper molecular dynamics. Al-though this results were derived for most simple cases of hydrogen and carbon dioxide, we could quantitatively explain why improperly large time step destroyed the molecular dynamics. From this study we could set the guide line of the proper time step for stable dynamics simulation in molecular modeling software.

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Analysis on Research Trends of Korean System Dynamics : Results and Reflections of 7 Years and Proposals (한국 시스템다이내믹스 연구경향분석 : 7년의 성과와 반성, 그리고 제안)

  • Hong, Young-Kyo;Jung, Seok-Hwan
    • Korean System Dynamics Review
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    • v.8 no.1
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    • pp.25-47
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    • 2007
  • This paper executes positive analysis about the thesis of 100 volumes which were published for 2000-2006 years through 'Korean System Dynamics Journal', to grope and to see the academic developments of Korean System Dynamics. The summarized analysis results are same as follows. First, Korean System Dynamics researches appear that quantitative researches are much more than qualitative ones. Second, the researches that aimed to solve problem are relatively much more than theory-oriented ones. Third, System Dynamics researches in the department of social science are more abundant than that of science and engineering. Based on these results, for establishing of Korean System Dynamics identity, we will work hard to study qualitative researches, increase the research domains and elevate the academic statue of System Dynamics.

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Emotional Engine Model based on Linear Dynamic Systems (선형 동적 시스템 기반의 감정 엔진 모델)

  • Ahn, Ho-Seok;Choi, Jin-Young
    • Proceedings of the KIEE Conference
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    • pp.213-215
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    • 2007
  • This paper introduces an emotional behavior decision model for intelligent service robots. An emotional model should make different behavior decisions according to the purpose of the robots. We propose an emotional behavior decision model which can change the character of emotional model and make different behavior decisions although the situation and environment remain the same. We defined each emotional element such as reactive dynamics, internal dynamics, emotional dynamics, and behavior dynamics by state dynamic equations. The proposed system model is a linear system. If you want to add one external stimulus or behavior, you need to add just one dimensional vector to the matrix of external stimulus or behavior dynamics. The case of removing is same. The change of reactive dynamics, internal dynamics, emotional dynamics, and behavior dynamics also follows the same procedure. We implemented the proposed emotional behavior decision model and verified its performance.

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System Dynamics Modelling on Religious Populations (종교 인구의 다이내믹스에 관한 시론적 모델)

  • Kim, Dong-Hwan
    • Korean System Dynamics Review
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    • v.15 no.3
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    • pp.37-59
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    • 2014
  • This paper is to study dynamics of populations of religions. As human population is a crucial source of social dynamics, the religious population is a driving force that changes political and cultural landscape of society. Although many christian scholars have reported important causal factors in changing population of christian world, there are few studies on the dynamics of religious population in system dynamics. This paper interprets these dynamic mechanisms in terms of feedback loops and constructs a basic system dynamic model to forecast future trend of religious population in Korean society.

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Study of Collective Synchronous Dynamics in a Neural Network Model

  • Cho, Myoung Won
    • Journal of the Korean Physical Society
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    • v.73 no.9
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    • pp.1385-1392
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    • 2018
  • A network with coupled biological neurons provides various forms of collective synchronous dynamics. Such phase-locking dynamics states resemble eigenvectors in a linear coupling system in that the forms are determined by the symmetry of the coupling strengths. However, the states behave as attractors in a nonlinear dynamics system. We here study the collective synchronous dynamics in a neural system by using a novel theory. We exhibit how the period and the stability of individual phase-locking dynamics states are determined by the characteristics of synaptic couplings. We find that, contrary to common sense, the firing rate of a synchronized state decreases with increasing synaptic coupling strength.

한국 시스템다이내믹스 연구경향분석;7년의 성과와 반성, 그리고 제안

  • Hong, Yeong-Gyo;Jeong, Seok-Hwan
    • Proceedings of the Korean System Dynamics Society
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    • pp.71-92
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    • 2007
  • This paper executes positive analysis about the thesis of 100 volumes which were published for 2000-2006 years through 'Korean System Dynamics proceeding', to grope and to see the academic developments of Korean System Dynamics. The summarized analysis results are same as follows. First, Korean System Dynamics researches appear that quantitative researches are much more than qualitative ones. Second, the researches that aimed to solve problem are relatively much more than theory-oriented ones. Third, System Dynamics researches in the department of social science are more abundant than that of science and engineering. Based on these results, for establishing of Korean System Dynamics identity, we will work hard to study qualitative researches, increase the research domains and elevate the academic statue of System Dynamics.

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Recent Developments in Multibody Dynamics

  • Schiehlen Werner
    • Journal of Mechanical Science and Technology
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    • v.19 no.spc1
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    • pp.227-236
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    • 2005
  • Multibody system dynamics is based on classical mechanics and its engineering applications originating from mechanisms, gyroscopes, satellites and robots to biomechanics. Multibody system dynamics is characterized by algorithms or formalisms, respectively, ready for computer implementation. As a result simulation and animation are most convenient. Recent developments in multibody dynamics are identified as elastic or flexible systems, respectively, contact and impact problems, and actively controlled systems. Based on the history and recent activities in multibody dynamics, recursive algorithms are introduced and methods for dynamical analysis are presented. Linear and nonlinear engineering systems are analyzed by matrix methods, nonlinear dynamics approaches and simulation techniques. Applications are shown from low frequency vehicles dynamics including comfort and safety requirements to high frequency structural vibrations generating noise and sound, and from controlled limit cycles of mechanisms to periodic nonlinear oscillations of biped walkers. The fields of application are steadily increasing, in particular as multibody dynamics is considered as the basis of mechatronics.

A Study on the Potentials of System Dynamics as a Tool to Understand the Community Welfare Practice (지역사회복지실천 이해 도구로서 시스템 다이내믹스의 가능성에 관한 고찰)

  • Cho, Sungsook
    • Korean System Dynamics Review
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    • v.14 no.1
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    • pp.89-104
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    • 2013
  • This study aims to explore the potentials of System Dynamics as a tool to understand the community welfare practice by paying attention to the strengths of System Dynamics to complement the weaknesses of the theories and studies of the community welfare practice. The contents of this study are as follows. First, it draws the limitations of its theories and studies by reviewing the literatures related. Second, it outlines the characteristics of the community welfare practice process as well as the strengths of System Dynamics as a tool to understand the community welfare practice. Third, it presents a causal loop model of System Dynamics applied to the community welfare practice process. Lastly, it concludes with the suggestions and implications of the key research findings. This study is expected to be a basic study to highlight the potentials of System Dynamics as a tool to understand the community welfare practice.

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Effect of Environmental Dynamics on the Business Performance of Franchise Distribution Industry (프랜차이즈 유통산업에서 환경 동태성이 가맹점의 경영성과에 미치는 영향에 관한 연구)

  • Park, Han-Seong;Kim, Joon-Ho;Yu, Jong-Pil
    • Journal of Distribution Science
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    • v.16 no.3
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    • pp.59-68
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    • 2018
  • Purpose - This study empirically examines the effects of environmental dynamics(dynamics of one's own company, dynamics of competitors, and dynamics of customers), within the franchise industry, on the dependence and conflict(dysfunctional conflict and functional conflicts) and the business performances(financial and non-financial). Furthermore, we empirically examined the effects of the dependence of franchise on the conflicts(dysfunctional conflict and functional conflict) and business performances(financial and non-financial). Finally, we empirically examined the effects of the conflicts of franchise (dysfunctional conflict and functional conflict) on the business performances(financial and non-financial). Research design, data, and methodology - Our study conducted a survey on the managers and owners of the franchises located in Seoul, Gyeonggi, and Incheon. The total number of valid samples was 230, and the structural equation model was analyzed by using AMOS program. Results - First, the environmental dynamics(dynamics of one's own company, dynamics of competitors, and dynamics of customers) in the franchise industry were shown to have statistically significant positive effect on the dependence of franchise. Second, among the environmental dynamics in the franchise industry, the dynamics of one's own company and the dynamics of the customers were shown to have a statistically significant positive effect on the dysfunctional conflicts of franchisees. However, in the franchise industry, the dynamics of competitors did not have a statistically significant effect on the dysfunctional conflict of the franchise. Third, in the franchise industry, the environmental dynamics(dynamics of one's own company, dynamics of competitors, and dynamics of customers) did not have a statistically significant effect on the functional conflicts of the franchises. Fourth, the dependence of franchise was shown to have a statistically significant positive effect on the conflicts(dysfunctional conflict and functional conflict). Fifth, the dysfunctional conflict of franchisees was shown to have a statistically significant negative effect on the business performances(financial and non-financial). Sixth, the functional conflicts of franchises was shown to have a statistically significant positive effect on business performances(financial and non-financial). Conclusions - From the franchise industry researches, the environmental dynamics were selected as the preceding factors and the relationship leading to dependence, conflict, and business performance were constructed into model.

The System Dynamics Model Development for Management Performance Forecasting of Small and Medium Hospital (BSC기반의 중소병원 경영성과예측 시스템다이내믹스 모델개발)

  • Chung, Hee-Tae;Kim, Yoon-Sin;Kwak, Sang-Man;Lee, Yong-kyoon
    • Korean System Dynamics Review
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    • v.8 no.2
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    • pp.209-234
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    • 2007
  • Recently, balanced scorecard is widely used in the public sector as well as in the private sector. Balanced scorecard system of a particular hospital is a very useful tool in the sense that it shows various measures for the management including the traditional financial measures. However, since it does not show the impact of action items, managers have to analyze his potential decisions. On the other hand, a system dynamics model for the management of a hospital can be used to predict future management status. In this paper, a balanced scorecard system with a system dynamics model is developed for a small sized hospital, and the feasibility and applicability of the system have been tested. It turns out the combination of the balanced scorecard and system dynamics technique can be comprised each other. The balanced scorecard system can take advantage of the data forecasted by the system dynamics model including the implementation of action items taken today. On the other hand, the key performance indicators and action items from the balanced scorecard system provide guidelines the scope and direction of the system dynamics model. The additional efforts of developing a system dynamics model are well compensated by the additional colorful functionalities of the system. This paper also covers the future research areas for the combined system to be more effectively developed.

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