• Title/Summary/Keyword: Global stability

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Intelligent Digital Redesign for Uncertain Nonlinear Systems Using Power Series (Powrer Series를 이용한 불확실성을 갖는 비선형 시스템의 지능형 디지털 재설계)

  • Sung Hwa Chang;Park Jin Bae;Go Sung Hyun;Joo Young Hoon
    • Journal of the Korean Institute of Intelligent Systems
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    • v.15 no.7
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    • pp.881-886
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    • 2005
  • This paper presents intelligent digital redesign method of global approach for hybrid state space fuzzy-model-based controllers. For effectiveness and stabilization of continuous-time uncertain nonlinear systems under discrete-time controller, Takagi-Sugeno(TS) fuzzy model is used to represent tile complex system. And global approach design problems viewed as a convex optimization problem that we minimize the error of the norm bounds between nonlinearly interpolated linear operators to be matched. Also, by using the power series, we analyzed nonlinear system's uncertain parts more precisely. When a sampling period is sufficiently small, the conversion of a continuous-time structured uncertain nonlinear system to an equivalent discrete-time system have proper reason. Sufficiently conditions for the global state-matching of tile digitally controlled system are formulated in terms of linear matrix inequalities (LMIs). Finally, a TS fuzzy model for the chaotic Lorentz system is used as an example to guarantee the stability and effectiveness of the proposed method.

A Study on Logistics Distribution Industry's IoT Situation and Development Direction (국내외 물류산업의 사물인터넷(IoT) 현황과 발전방향에 관한 연구)

  • Park, Young-Tae
    • Management & Information Systems Review
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    • v.34 no.3
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    • pp.141-160
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    • 2015
  • IoT(Internet of Things) has become a major issue as new type of convergence technology, expending existing of USNs(Ubiquitous Sensor Networks), NFC(Near Field Communication), and M2M(Machine to Machine). The IoT technology defines as a networking for things, which can establish intelligent links collaboratively for sensing networking and processing between each other without human intervention. The purpose of this study is to investigate to forecast the future distribution changes and orientation of contribution of distribution industry on IoT and to provide the implication of distribution changes. To become a global market leader, IoT requires much more development of core technology of IoT for distribution industry, new service creation and try to use a market-based demand side strategy to create markets. So, to become a global leader in distribution industry, this study results show that first of all establishment of standardization of IoT, privacy safeguards, security issues, stability and value were more important than others. The research findings suggest that the development goals of IoT should strive to boost the creation of a global leader in distribution industry and convenience to consider consumers' demands as the most important thing.

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Climate Change and Its Impact on Agricultural Ecosystem (기후변화에 따른 농업생태계 변동과 대책)

  • Yun Seong Ho
    • Proceedings of the Korean Society of Crop Science Conference
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    • 1998.10a
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    • pp.313-335
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    • 1998
  • If the atmospheric concentrations of greenhouse gases double, the annual temperature increase in mean surface temperature relative to 1990 will be about 2.0 to $2.5^{\circ}C$ and the annual precipitation increase about $15{\%}$ by 2100 in Korea. When the temperature rises $2^{\circ}C$, the annual temperature will be $13^{\circ}C,\;15^{\circ}C,\;and\;16^{\circ}C$ in Western Central, Yeongnam Basin, and Southern Coastal respectively. Consequently the crop period could be prolonged $10{\~}29$ days. In the case of gradual global warming, annual crops could be adapted to the changed environment by breeding, and the perennial crops should be shifted to ether area. If global warming happens suddenly over the threshold of atmospheric greenhouse gases concentration, then we shall have disturbance of ecosystem. When $2^{\circ}C$ higher than present, the optimum flowering date of rice plant delayed about 10 days, so it may not possible to adopt the fate with present japonica rices, therefore, the recommended characteristics of rice varieties are longer basic vegetative period, more late maturing and higher ripening temperature. Barley and wheat crops could be shifted to northern coastal areas and apple production areas should be shifted to those areas under $13.5^{\circ}C$ in annual mean temperature at global warming. Ideotypes of crops under climate changes should have such ecological characteristics that are indispensable to accomplish the sustainable agriculture under increased $CO_{2}$ and temperature condition as the diversification of genetic resources from yield-oriented to biomass-oriented characteristics with the higher potentials of $CO_{2}$ absorption and Primary production. In addition, a heat-tolerance, a pest resistance, an environmental adaptability and a production stability should be also incorporated collectively into our integrated agroecosystem.

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The Impact of COVID-19 and Korea's New Southern Policy on Its Global Value Chain

  • Yoo, Jeong-Ho;Park, Seul-Ki;Cheong, In-Kyo
    • Journal of Korea Trade
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    • v.24 no.8
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    • pp.19-38
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    • 2020
  • Purpose - The Korean government has been promoting the New Southern Policy (NSP) prior to the onset of the COVID-19 pandemic, which damage global value chain (GVC). The purpose of this paper is to emphasize that the NSP should be developed to provide tangible support in corporate GVC adjustment, away from diplomatic activities in order to offset GVC losses due to COVID-19 and expand export capabilities. Design/methodology - Two research methodologies are combined for this paper: A computational general equilibrium (CGE) model is used to estimate the impacts of the COVID-19 pandemic and NSP on Korea's exports, and the decomposition methodology (Wang, Wei and Zhu, 2013) to evaluate the stability of GVC. The conventional CGE model was modified to obtain an estimate for decomposition. The research methodology adopted in this study was attempted for the first time, and it can be widely used in future GVC research. Findings - Results found the effects of COVID-19 reduced Korea's total exports by 27% and GVC by more than 30%. In particular, VA in Korea's exports to the NSP region was found to have a huge impact in heavy industries and textiles, and its exports to Vietnam seemed to suffer the largest loss in GVC among ASEAN countries. If the NSP is implemented properly, it appears that it could offset much of the negative impacts of COVID-19, implying the importance of the effectiveness of the NSP. Originality/value - Many papers have assessed the NSP descriptively, and the GVC has been a topic for many publications. However, the impact of COVID-19 on Korea's GVC with the NSP countries has not been quantitatively studied. This paper emphasizes that the NSP should be pursued based on the results of quantitative analysis. In addition, the research methodology of this paper can be used for other GVC research with relevant modifications.

Empirical Study of Cross-Border E-commerce Brand Formation

  • Jing Zhang;Ziyang Liu
    • Journal of the Korea Society of Computer and Information
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    • v.28 no.11
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    • pp.209-226
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    • 2023
  • Cross-border e-commerce has emerged as a crucial force in stabilizing China's foreign trade, driving the transformation and upgrade of China's foreign trade, and contributing to global economic development and stability. As a result, promoting the high-quality development of cross-border e-commerce has become a common challenge within the Chinese industry. However, with the rapid growth of cross-border e-commerce, it faces new phenomena and challenges, such as a mix of quality, fierce competition, and price competition. Brands serve as distinguishing markers for identifying entities, and brand building is a prudent choice for achieving high-quality development in cross-border e-commerce. This article utilizes brand theory, employing a combined qualitative and quantitative approach, with a specific focus on key elements within the operations of cross-border e-commerce enterprises. Through an analysis of the key elements influencing the formation and development of brands within the internal operations of Chinese cross-border e-commerce enterprises, it investigates their internal formation mechanisms and assesses the significance of these critical factors in influencing brand formation. The research process is based on data from overseas consumers, conducting empirical analysis, ultimately providing certain guidance for brand development in cross-border e-commerce enterprises.

A New National Security Strategy for South Korea: Exploring the Implementation of Positive Peace (한국의 새로운 국가 안보 전략: 적극적 평화 구축 방안 연구)

  • Choul-Hee Lee;Kyoung-Haing Lee;Sang Hyuk Park
    • The Journal of the Convergence on Culture Technology
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    • v.10 no.4
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    • pp.457-465
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    • 2024
  • In the 21st century, the global security environment has undergone rapid changes, presenting South Korea with complex security dilemmas. This study aims to explore a new national security strategy for South Korea through the implementation of 'Positive Peace.' Based on Johan Galtung's concept of 'Positive Peace,' the study proposes a comprehensive approach to build sustainable peace by redesigning the peace process on the Korean Peninsula, establishing a multilateral security cooperation framework in Northeast Asia, expanding global peace contributions, promoting domestic social integration, and spreading a culture of peace. To realize these goals, the study discusses the need to redefine the role of the military, reallocate defense budgets, introduce the concept of a peace dividend, promote the peaceful use of science and technology, and legislate for the realization of the right to peace. The implementation of a 'Positive Peace' strategy aims to transform South Korea into a leading nation in peace, contributing to the peace and stability of the Korean Peninsula, Northeast Asia, and the global community.

Design of Sedimentary Rock Slopes in River Diversion Works (가배수로 터널공사의 퇴적암 사면 안정화 설계)

  • Jee, Wang-Ruel
    • Geotechnical Engineering
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    • v.14 no.6
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    • pp.17-32
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    • 1998
  • The Bakun hydroelectric project includes the construction of a hydroelectric power plant with an installed capacity of 2,520MW and a power transmission system connecting to the existing transmission networks in Sarawak and Western Malaysia, The power station will consist of a 210m height concrete faced rockfill dam. During the construction of the dam and the power facilities the Balui river has to be diverted by three diversion tunnels with a length of some 1,400m each. The inner diameter of the tunnels is 12m and the tunnel width is 16m at the portal area. This paper describes the stability analysis and design methods for the open cut rock slopes in the inlet and outlet area of the diversion tunnels. The geotechnical parameters employed in stability calculations were given as a function of four. defined Rock Mass Types (RMT) which were based on RMR system from Bieniawski. The stability calculations procedure of the rock slopes are divided into two stages. In the first stage, it is calculated for the stability of each 'global' slope without any rock support and shotcrete system. In the second stage, it is calculated for each 'local'slope stability with berms and supported with rock bolts and shotcrete. The monitoring instrumentation was performed continuously and some of the design modification was carried out in order to increase the safety of failed area based on the unforeseen geological risks during the open cut excavation.

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The Analysis of the current state and components of Korea's National Debt (한국의 국가채무 현황과 구성요인 분석)

  • Yang, Seung-Kwon;Choi, Jeong-Il
    • Journal of Digital Convergence
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    • v.18 no.9
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    • pp.103-112
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    • 2020
  • The purpose of this study is to examine the current status and components of Korean National Debt and to analyze the effects of each component on National Debt. In the Korean Statistical Information Service (KOSIS), we searched for data such as General Accounting Deficit Conservation, For Foreign Exchange Market Stabilization, For Common Housing Stability, Local Government Net Debt Public Funds, etc that constitute National Debt. The analysis period used a total of 23 annual data from 1997 to 2019. The data collected in this study use the rate of change compared to the previous year for each component. Using this, this study attempted index analysis, numerical analysis, and model analysis. Correlation analysis result, the National Debt has a high relationship with the For Common Housing Stability. For Foreign Exchange Market Stabilization, Public Funds, etc., but has a low relationship with the Local Government Net Debt. Since 1997, National Debt has been increasing similarly to the For Foreign Exchange Market Stabilization, For Common Housing Stability and Public Funds etc. Since 2020, Korea is expected to increase significantly in terms of For Common Housing Stability and Public Funds, etc due to Corona19. At a time when the global economic situation is difficult, Korea's National Debt is expected to increase significantly due to the use of national disaster subsidies. However, if possible, the government expects to operate efficiently for economic growth and financial market stability.

Analysis of Design Parameters for Power Plant Breakwater Channels Using Geotextile Containment (지오텍스타일 컨테인먼트를 활용한 발전소 방파수로 설계인자 분석)

  • Kim, Sung-Hwan;Oh, Young-In
    • Journal of the Korean Geosynthetics Society
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    • v.7 no.3
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    • pp.1-7
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    • 2008
  • The geotextile tube shall be sewen with geotextile longitudinally in the shape of hose and it shall be filled hydraulically through filling ports at the proper intervals to construct structure. Geotextile container shall be sewen after spreading of geotextile on the split barge and sealed shut after the filling soil, and then moved and positioned at the required position. And the geotextile container passes through the bottom of barge by opening split barge and drops to the seabed to form structure. This structure for the ${\bigcirc}{\bigcirc}$ project, UAE and we would propose that geotextile containment for core material of power plant breakwater to be constructed for lower bunds with containers up to -4.0m and do upper parts with the structures of tube up to 0.0m. For the application of proposed geotextile containment, review on stability of breakwaters and design consideration were adopted. The evaluation on stability of geotextile containment was classified by 3 items, internal design consideration for material selection, reviews on stability for individual and global structure. In this research, the geothermal analysis was performed to estimate the geothermal behavior of central breakwater. Central breakwater is located boundary of intake and outfall channel, it is mean that the central breakwater is thermal boundary of intake low temperature sea water and outfall high temperature sea water. Therefore, it is required to be designed a low permeability to ensure no mix of intake and outfall waters.

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Stability of the Divergent Barotropic Rossby-Haurwitz Wave (발산 순압 로스비-하우어비츠 파동의 안정성)

  • Jeong, Han-Byeol;Cheong, Hyeong-Bin
    • Journal of the Korean earth science society
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    • v.37 no.2
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    • pp.107-116
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    • 2016
  • Stability of the barotropic Rossby-Haurwitz wave is investigated using the numerical models on the global domain. The Rossby-Haurwitz wave under investigation is composed of the basic zonal flow of super-rotation and a finite amplitude spherical harmonic wave. The Rossby-Haurwitz wave is given as either steady or unsteady wave by adjusting the strength of the super-rotating zonal flow. Stability as well as the growth rate of the wave in the numerical simulation is determined by comparing the perturbation amplitude at two different time stages. Unstable modes of the Rossby-Haurwitz wave exhibited a horizontal structure composing of various zonal-wavenumber components. The vorticity perturbation for some modes showed a discontinuity around the area of weak flow, which was found robust regardless of the horizontal resolution of the model. Fourier finite element model was shown to generate the unstable mode in earlier stage of the time integration due to less accuracy compared to the spherical harmonic spectral model. Taking the overall accuracy of the models into consideration, the time by which the unstable mode begin to dominate over the spherical harmonic wave was estimated.