• 한국시스템다이내믹스학회:학술대회논문집
• /
• 한국시스템다이내믹스학회 2000년도 학술대회발표논문집
• /
• pp.29-37
• /
• 2000

In this paper an attempt is made to understand contribution factors in the field of electronic commerce(EC). To do that, we adopt and modify an existing commerce model. The following two major conclusions are drawn from our simulation. Most of all, the diminution of information delay introduce monotonous growth rather than fluctuation of EC market. The stable increase of revenue or market scale makes us decide the employment or capacity scale quickly. Second, for favorable and continuous evolution of EC, utilization system of electronic money should be established steadily. The following findings strongly support our claim: We found full oscillation of EC market when electronic money system didn't established well. On the contrary, if electronic money system could provide fast cash flow and fully trustful function, decisions of company or consumer would be executed promptly.

• 한국시스템다이내믹스연구
• /
• 제10권4호
• /
• pp.27-37
• /
• 2009

This study has been performed to consider how to support to be effectively linked hiring of skilled human resources that were discharged through actually related education programs, as demand of they are recently being increased due to the expansion of the logistics market, and effort to train them is being propelled. That is associated with the Busan region, and field of logistics service is 3PL that is seriously considered the area of professional services at the last logistics market. Through the methodology of System dynamics, this study has been modeled about dynamic mechanism considered the growth of logistics marker and relation to employment, and has been estimated about ripple effect within logistics market of major policies related with them.

• 한국시스템다이내믹스연구
• /
• 제17권3호
• /
• pp.145-173
• /
• 2016

This study aims to develop strategic diagnosis framework of performance by identifying and analysing the dynamics of the technology commercialization ecosystem in innovative region. To achieve the purpose of this study, the systems thinking approach is used. The systems thinking approach connects feedback structure and behavior more explicitly to diagnosis vicious feedback loop in the regional technology commercialization ecosystem. In terms of an ecological point of view, it will be possible to explore dominant feedback structure and find leverages to overcome the limitations of regional technology commercialization performance. The diagnosis of reenforcing and balancing feedback structure is based on the statistical analysis of the survey data which has been collected in a cluster random sampling method, targeting on the 200 firm located in the Pangyo and Daeduk region. The results from this research showed that the regional technology commercialization ecosystem was immature and faced limit to the growth. An important finding of this study was that regional technology commercialization ecosystem need to activation of startups and reinforcement of virtuous feedback structures of technology commercialization market systems.

• 한국시스템다이내믹스연구
• /
• 제7권1호
• /
• pp.147-172
• /
• 2006

With the purpose of long-range planning toward local/regional sustainable development, it is desired to avoid unconditional industrialization and expansion and to build an eco-oriented development strategy considering site-specific characteristics of the environment. This paper thus aims at the elaboration of a system dynamics model of a locality/region so as to understand inherent dynamics of sustainable development and to assess the effectiveness of such an eco-oriented strategy. The model thus consists of several positive and negative feedback loops that accelerate or restrict local/regional economic growth within a system boundary incorporating the environment, economy, and society. The model is moreover applied to the assessment of the effectiveness of the development plan recently established in Damyang in JeollaNamdo, Korea. It is regarded in this case to be effective for population immigration and economic prosperity to give priority to restore the bamboo ecosystem and nourish a series of eco-friendly industries based on the bamboo items developed recently. It is also to be positive to sustainable development since it enables to maintain high quality of the environment from the outset of their development steps.

• 한국물환경학회지
• /
• 제24권5호
• /
• pp.550-555
• /
• 2008

This study was conducted to assess the growth characteristics of phytoplankton and to understand seasonal dynamics of phytoplankton in response to limiting nutrients in an agricultural reservoir from November 2002 to December 2003. Marked increase of chl.a concentration observed in July ($99.0{\mu}g/L$) and November ($109.7{\mu}g/L$) after heavy rainfall. TP concentration ranged $48.0{\sim}126.6{\mu}g/L$, and its the temporal variation was similar to that of chl.a concentration. Microcystis spp., dominant phytoplankton species were used for the growth kinetics experiment, except for the season when Aulacoseira spp. (March, April) and Aphanocapsa sp. (May) dominated. In the temperature range between $10{\sim}25^{\circ}C$, the rate of growth increase per $10^{\circ}C$ was almost two folds. The highest maximum growth rate (${\mu}_{max}=1.09day^{-1}$) of phytoplankton observed September, and ${\mu}_{max}$ was lowest ($0.34day^{-1}$) in March when Aulacoseira spp. dominated. The ${\mu}_{max}$ ($0.78{\pm}0.20day^{-1}$) was relatively high in the summer season when water temperature is above $20^{\circ}C$ and cyanobacteria dominated compared to the spring when diatoms dominated ($0.43{\pm}0.08day^{-1}$). The maximum growth rate ($0.55{\pm}0.12day^{-1}$) and the half saturation concentration ($K_s=0.73{\pm}0.15{\mu}M$) of cyanobacteria during winter season (November, December) was higher than those of diatoms. However, the ${\mu}_{max}$ and $K_s$ of cyanobacteria in December was similar to those of diatom, reflecting that diatom cell quota (Mean 48.4 pgP/cell) was greater than cyanobacteria (34.0 pgP/cell) during this time.

• The Korean Journal of Ecology
• /
• 제18권1호
• /
• pp.17-30
• /
• 1995

The growth of Scenedesmus quadricauda (Trup.) Breb. is enhanced by methylyoxal (MG), a general inhibitor of cell division, at threshold concentration in conjunction with reatment timing relative to growth stage. The stimulatory effect of MG on algal cell growth was most significant with 2.27-fold of untreated algal culture in cell number when 0.5 mM of MG was added to the algal culture at the beginning of logarithmic phase with an initial MG concentration of 0.535 mg $MG/10^6cell$. A Specific growth rates (SGRs) of MG-treated cultures were rapidly increased at the beginning of logarithmic phase with 1.89-fold of untreated algal culture. Cultures inoculated with high cell numbers of 2.4 to 4.8 X $10^4$ cells/ml were less sensitive to 0.5 mM of MG treatment. The algal cell division was ranged from 0.392 to 0.924 mg MG/106 cell. If the cell number of an algal culture at the time of inoculation was low (0.6 X $10^4$ cells/ml) and MG was added before logarithmic phase, the cell number of 0.5 mM of MG-treated cultures were lower than those of controls. In algal cultures treated with high concentrations of MG (1.0 mM and 2.0 mM), the algal growth was inhibited. Photosynthetic rate of growth-enhanced algal by 0.5 mM of MG was significantly higher than that of untreated or 1.0 mM of MG-treated algal cell, while there was no significant difference among those groups in respiratory rate. Pyruvate concentration in 0.5 mM of MG-treated culture was incrcased agter methylglyoxal trcatment.

• The Korean Journal of Ecology
• /
• 제24권6호
• /
• pp.341-348
• /
• 2001

Population dynamics of the oldest relic stand of Pinus densiflora for. erecta which remains as a status of patch in Sokwang-Ri area, Uljin-Gun, was studied to provide the basic data for conservation of the oldest pine stand in Korea. The upper slope site and ridge site including total 12 plots mainly represented Pinus densiflora for. erecta and Quercus mongolica. These two tree species showed reverse J-shaped distribution. From this information, it was concluded that intensive interspecific competition between two species could be occurring. Age distribution of P. densiflora for. erecta on the sites above middle slope area was indicated bi-modal type or tri-modal type which was known as an age structure of climax forest. Therefore, it was estimated that Pinus densiflora for. erecta population could be continuously maintained in the each patch above middle slope area. In the valley sites, hardwood species such as Q. mongolica, Q. variabilis, Styrax obassia and Acer pseudosieboldianum occupied most part of the under crown-cover area and their seedlings and saplings were developing into the closed upper layer crown because the height of upper layer crown reached about 35 meters and such a high crown height was more suitable for light utilization by plants of under layer. The growth patterns were mainly fluctuated for the entire life time of the oldest tree caused by frequent disturbance. And the initial growth curves of the mature trees and suppressed juvenile trees showed different tendencies along the sites.

• 한국시스템다이내믹스연구
• /
• 제15권2호
• /
• pp.51-74
• /
• 2014

Over the past few years Korea has achieved rapid economic growth, while the deepening polarization of income has negatively affected Korea economy and society. It can be the reason of this negative effect on economy that the increased income by the economic growth has not been distributed socially, but overly focused on one part of social class. One of the important and powerful solution of social polarization could be the strengthening of the income distribution. In these circumstances, the social interest and discussion on the universal welfare system and on the basic income as the means of income redistribution have been increasing. In this study, a system dynamic analysis was conducted to find how an universal cash payment as basic income providing cash benefits impacts on the promotion of consumption in private sector, of local jobs and of local economic organizations. Recently, the poor energy consumption ability of energy poverty became one of the social problems. Also it was analysed how an energy payment-in-kind as basic income influences on the energy consumption of the region, the energy production capacity, the promotion of local energy. The universal cash payment and energy payment-in-kind as the basic income policy showed similar and positive effects on the local economy system and on the local energy system respectively.

• The Korean Journal of Ecology
• /
• 제16권3호
• /
• pp.329-339
• /
• 1993

Effects of relative light intensity and N, P fertilization on the growth and ramet dynamics of the rhizomatous plants, Arundinella hirta, Miscanthus sinensi and Spdiopogon sibiricus were studied in Chuncheon, Kangweon-Do. Ramets emerged in one pulse a year, withered in one pulse at the end of the growing season in M. sinensis and S. sibircus stands, while the birth and death pulse in A. hirta stands were two times. Total births of ramet were 9 times and 3.6 times greater in the unshaded fertilized stands of A. hirta and M. sinensis than in the shaded, However, those of S.sibiricus were 2.1 times greater in the shaded stands. Flowering rates of A. hirta, M.sinensis and S.sibiricus I the unshaded fertilized stands were 1.8, 2.7 and 1.04 times greater than in the shaded unfertilized stands, respectively. Height of ramets of A. hirta and M.sinensis were the hightest in the unshaded fertilized stands. However, that of s.sibiricus was the highest in the shaded fertilized stand. Aboveground production of A.hirta in the fertilized stand was 2.4 times greater in the unshaded stand than in the shaded one. Results of inflorescence frequency, shoot height and the ratio of aboveground to belowground were smiliar to the total births. The added fertilizer markedly increased the ramet density and the shoot productivity of three rhizomatous plants, especially of A. hirta.

• 한국결정성장학회지
• /
• 제15권4호
• /
• pp.168-174
• /
• 2005

건조공정 중인 다공성 물질의 물성은 재료의 비균질성 즉 전위, 입자, 입계, 균열, 기공과 같은 미시적인 결함 인자들의 영향을 받는다. 따라서 다공성 물질의 건조공정을 전산 시뮬레이션하기 위해서는 연속체 스케일과 원자 스케일해석 그리고 스케일별 해석 한계 극복이 요구된다. 본 연구에서는 분자동역학 시뮬레이션으로 계산한 나노스케일 물성를 연속체 스케일 해석에 연계하는 계층적 멀티스케일 시스템을 구축하고, 다공성 세라믹 애자의 건조공정을 전산 시뮬레이션 하였다. 해석 결과, 온도, 습도, 변형률 그리고 응력 분포를 기존의 결과들과 비교하여 검증하였다.