• Molecules and Cells
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• 제41권12호
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• pp.1045-1051
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• 2018

The developmentally regulated GTP binding protein 2 (DRG2) is involved in the control of cell growth and differentiation. Here, we demonstrate that DRG2 regulates microtubule dynamics in HeLa cells. Analysis of live imaging of the plus-ends of microtubules with EB1-EGFP showed that DRG2 deficiency (shDRG2) significantly reduced the growth rate of HeLa cells. Depletion of DRG2 increased 'slow and long-lived' subpopulations, but decreased 'fast and short-lived' subpopulations of microtubules. Microtubule polymerization inhibitor exhibited a reduced response in shDRG2 cells. Using immunoprecipitation, we show that DRG2 interacts with tau, which regulates microtubule polymerization. Collectively, these data demonstrate that DRG2 may aid in affecting microtubule dynamics in HeLa cells.

• 한국시스템다이내믹스연구
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• 제10권4호
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• pp.39-51
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• 2009

In this paper, we constructed a cognitive map of President Lee of Korea on the policy vision of green growth. This cognitive map is characterized by a scarcity of feedback loops and a strong emphasis on the positive loops. These characteristics can be understood by the fact that the green growth policy is to overcome the limits to growth coming from negative feedback loops. As a conclusion, we proposed a negative feedback loop approach to the green growth policy vision, which might minimize the side effects of positive loops.

• 한국시스템다이내믹스연구
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• 제10권3호
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• pp.47-79
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• 2009

The paper examines dynamic relationship among 'Limit to Growth' factors in Korea using causal loop diagram. It also aims to explore policy implications for Korea in overcoming current difficulties and future crisis we may face. For this purpose, five factors -economy, population, resource, environment, food- used in the were adopted as an analytical framework. Findings show that Korea is fragile to external shock such as world economic crisis, food price surge, and resource price -including energy price- hike. High dependency of energy, food and resource on foreign market was found to be a major source of limit to growth in Korea. Furthermore, environmental problems like global warming could be a major external shock that could hit Korea harder than the rest of the world. Policy implications and measures for these problems were discussed too.

• Journal of Microbiology and Biotechnology
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• 제29권4호
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• pp.558-561
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• 2019

This study aimed to understand the survival and growth patterns of bacteriophage-sensitive Weissella and Leuconostoc strains involved in kimchi fermentation. Dongchimi kimchi was prepared, and Weissella and Leuconostoc were co-cultivated in the dongchimi broth. Weissella cibaria KCTC 3807 growth was accompanied by rapid lysis with an increase in the bacteriophage quantity. Leuconostoc citreum KCCM 12030 followed the same pattern. The bacteriophage-insensitive strains W. cibaria KCTC 3499 and Leuconostoc mesenteroides KCCM 11325 survived longer under low pH as their growth was not accompanied by bacteriophages. The bacteriophage lysate of W. cibaria KCTC 3807 accelerated and promoted the growth of Leuconostoc. Overall, our results show that bacteriophages might affect the viability and population dynamics of lactic acid bacteria during kimchi fermentation.

• 한국시스템다이내믹스연구
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• 제15권4호
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• pp.101-127
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• 2014

This study aims to understand how and why each stage of capitalism grows and changes into the new direction in the moment of crisis, based on the systems thinking approach through the causal loop feedback structure. To achieve the research purpose, it classifies the evolution process of the capitalistic economic system into 4 types: Capitalism 1.0(Classical Laissez-Faire Capitalism), 2.0(Revised Capitalism), 3.0(Neo-liberalism), and 4.0(New Capitalism for the Future). This study focuses particularly on by which feedback structure the growth, crisis, and new transition of capitalism could be explained. The main research results are as follows. The intended positive feedback structure caused the growth at each early stage of capitalism. After that time, as a result of the uncontrolled growth, the negative feedback structure controlling its growth operated on the one hand, while the positive feedback structure amplifying the crisis did on the other hand. The study suggests the Resilient Capitalism as the new evolutional direction of Capitalism 4.0. It can contribute to strengthening its resilience by which all the economic players can recover promptly and flexibly from the crises such as the failure of competition and unemployment.

• 한국유기농업학회지
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• 제25권4호
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• pp.805-819
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• 2017

The study was carried out to develop a mathematical model for evaluating the effect of organic fertilizers in organic rice production systems. A function to simulate the nitrogen mineralization process in the paddy soil has been developed and integrated into ORYZA2000 crop growth model. Inorganic nitrogen in the soil was estimated by single exponential models, given temperature and C:N ratio of organic amendments. Data collected from the two-year field experiment were used to evaluate the performance of the model. The revised version of ORYZA2000 provided reasonable estimates of key variables for nitrogen dynamics and crop growth in the organic rice production systems. Coefficient of determination between the measured value and simulated value were 0.6613, 0.8938, and 0.8092, respectively for soil inorganic nitrogen, total dry matter production, and rice yield. This means that the model could be used to quantify nitrogen supplying capacity of organic fertilizers relative to chemical fertilizer. Nitrogen dynamics and rice growth simulated by the model would be useful information to make decision for organic fertilization in organic rice production systems.

• 한국시스템다이내믹스연구
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• 제3권1호
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• pp.5-42
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• 2002

The main purpose of this paper is analyzing long-term growth possibility of a telecommunication Company (Telco) H. First of all, to achieve this purpose, the precise understanding about causal relations among growth and decay factors of Telco H is required. Based upon the causal analysis, a basic computer simulation model is developed. Finally, several predictive examinations about growth possibility and pattern of the Telco H are conducted using three scenarios. From simulation results, the most important policy leverages are capabilities of market share sustenance, improvement of service quality and squeezing current network facility to elevate profitability and efficiency. Recently, telecommunication industry has become more and more competitive due to introduction of Internet and deregulation. Internet has brought about global competition as well as confusion between telecommunication and broadcasting industries. At the almost same time, deregulation is a universal tendency and a catalyst of unlimited competition. Telco H has been a dominant company in Korea for last century. However, the dominant position of Telco H has been threatened by the change of competition environment. The competitive environment has many elements and keeps changing dynamically. Therefore, System Dynamics simulation methodology is adopted to examine the problem.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.433-433
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• 2011

Since the concept of graphene was established, it has been intensively investigated by researchers. The unique characteristics of graphene have been reported, the graphene attracted a lot of attention for material overcomes the limitations of existing semiconductor materials. Because of these trends, economical fabrication technique is becoming more and more important topic. Especially, the epitaxial growth method by sublimating the silicon atoms on Silicon carbide (SiC) substrate have been reported on the mass production of high quality graphene sheets. Although SiC exists in a variety of polytypes, the 3C-SiC polytypes is the only polytype that grows directly on Si substrate. To practical use of graphene for electronic devices, the technique, forming the graphene on 3C-SiC(111)/Si structure, is much helpful technique. In this paper, we report on the growth of graphene on 3C-SiC(111) surface. To investigate the morphology of formed graphene on the 3C-SiC(111) surface, the radial distribution function (RDF) was calculated using molecular dynamics (MD) simulation. Through the comparison between the kinetic energies and the diffusion energy barrier of surface carbon atoms, we successfully determined that the graphitization strongly depends on temperature. This graphitization occurs above the annealing temperature of 1500K, and is also closely related to the behavior of carbon atoms on SiC surface. By analyzing the results, we found that the diffusion energy barrier is the key parameter of graphene growth on SiC surface.

• Journal of Magnetics
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• 제16권3호
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• pp.308-311
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• 2011

In order to obtain mono-dispersed Fe NPs with high saturation magnetization, quantitative analysis method to investigate the growth dynamics of the Fe NPs synthesized by a conventional thermal decomposition method has been developed. As a result, fast nucleation process promotes formation of ~4 nm of initial nucleus with a non-equilibrium phase, resulting in low saturation magnetization. And slow particle growth with atomic-scaled surface precipitation mode (< 100 atoms/($min{\cdot}nm^2$)) can form the growth layer on the surface of initial nucleus with high saturation magnetization (~190 emu/$g_{Fe}$) as an equilibrium a phase of Fe. Therefore, higher stabilization of small initial nucleus generated just after the injection of $Fe(CO)_5$ should be one of the key issues to achieve much higher $M_s$ of Fe NPs.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2009년도 임시총회 및 하계학술연구발표회
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• pp.53-54
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• 2009