• 제목/요약/키워드: uncertain environment

검색결과 325건 처리시간 0.031초

Neuro-Fuzzy Systems: Theory and Applications

  • Lee, C.S. George
    • 제어로봇시스템학회:학술대회논문집
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    • 제어로봇시스템학회 2001년도 ICCAS
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    • pp.29.1-29
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    • 2001
  • Neuro-fuzzy systems are multi-layered connectionist networks that realize the elements and functions of traditional fuzzy logic control/decision systems. A trained neuro-fuzzy system is isomorphic to a fuzzy logic system, and fuzzy IF-THEN rule knowledge can be explicitly extracted from the network. This talk presents a brief introduction to self-adaptive neuro-fuzzy systems and addresses some recent research results and applications. Most of the existing neuro-fuzzy systems exhibit several major drawbacks that lead to performance degradation. These drawbacks are the curse of dimensionality (i.e., fuzzy rule explosion), inability to re-structure their internal nodes in a changing environment, and their lack of ability to extract knowledge from a given set of training data. This talk focuses on our investigation of network architectures, self-adaptation algorithms, and efficient learning algorithms that will enable existing neuro-fuzzy systems to self-adapt themselves in an unstructured and uncertain environment.

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침투에 대한 불포화 사면의 신뢰성 해석 (Reliability-Based Analysis of Slope Stability Due to Infiltration)

  • 조성은;이종욱;김기영;전제성
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2005년도 지반공학 공동 학술발표회
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    • pp.649-654
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    • 2005
  • Shallow slope failures in residual soil during periods of prolonged infiltration are common over the world. One of the key factors that dominate slope stability is hydrological response associated with infiltration. Hence, the soil-water profile during rainfall infiltration into unsaturated soil must me examined to evaluate slope stability. However, the hydraulic response of unsaturated soil is complicated by inherent uncertainties of the soil hydraulic properties. This study presents a methodology for assessing the effects of parameter uncertainty of hydraulic properties on the response of a analytical infiltration model using first-order reliability method. The unsaturated soil properties are considered as uncertain variables with means, standard deviations, and marginal probability distributions. Sensitivities of the probabilistic outcome to the basic uncertainties in the input random variables are provided through importance factors.

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Numerical and experimental study for Datong coal gasification in entrained flow coal gasifier

  • Park, Y. C.;Park, T. J.;Kim, J. H.;Lee, J. G.
    • 한국에너지공학회:학술대회논문집
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    • 한국에너지공학회 2001년도 추계 학술발표회 논문집
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    • pp.69-76
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    • 2001
  • The coal gasification process of a slurry feed type, entrained-flow coal gasifier was numerically predicted in this paper. By divding the complicated coal gasification process into several simplified stages suh as slurry evaporation, coal devolitilisation and two-phase reactions coupled with turbulent flow and two-phase heat transfer, a comprehensive numerical model was constructed to simulate the coal gasification process. The k-$\varepsilon$turbulence model was used for the gas phase flow while the Random-trajectory model was applied to describe the behavior of the coal slurry particles. The unreacted-core shrinking model and modified Eddy Break-Up(EBU) model were used to simulate the heterogeneous and homogeneous reactions, respectively. The simulation results obtained the detailed informations about the flow field, temperature inside the gasifier. Meanwhile, the simulation results were compared with the experimental data as function of $O_2$/coal ratio. It illustrated that the calculated carbon conversions agreed with the measured ones and that the measurd quality of the atngas was better than the calculated one when the $O_2$/coal ratio increases. The result was related with the total heat loss through the gasifier and uncertain kinetics for the heterogeneous reactions.

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Counteractions against Changes of Logistics Environment in Northeast Asia

  • Roh, Byeong-Gwon;Kim, Hui-Su;Yoo, Chang-Gwon;Kim, Gi-Pyoung
    • 유통과학연구
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    • 제13권5호
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    • pp.23-31
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    • 2015
  • Purpose - This study investigated competitive counteractions necessary for continuous growth in a rapidly changing logistics environment in Northeast Asia. Research Design, Data, and Methodology - Using a time series analysis, the study first investigated Northeast Asian trade scale and volume by examining online and offline material from the Ministry of Ocean and Fisheries, Busan Port Authority, and other government agencies. A literature survey was done to investigate the state and prospect of the logistics environment in Northeast Asia including changes in freight volume at major ports in the three Northeast Asian countries. Result - The results of the study suggest using the Trans-Korean Railroad (TKR), as well as promoting the North Pole and South Pole routes, to compete against changes in trade volume and the logistics environment in Northeast Asia. A SWOT analysis was done to examine the effectiveness of these strategies. Conclusions - The findings indicate that the TKR impact, using the Busan Port connecting the Trans-China Railway (TCR), the Trans-Siberian (TSR), and the North Pole Route, may be uncertain in practice considering the uncertainty in international politics.

Antibiotic resistance in livestock, environment and humans: One Health perspective

  • Sriniwas Pandey;Hyunok Doo;Gi Beom Keum;Eun Sol Kim;Jinok Kwak;Sumin Ryu;Yejin Choi;Juyoun Kang;Sheena Kim;Na Rae Lee;Kwang Kyo Oh;Ju-Hoon Lee;Hyeun Bum Kim
    • Journal of Animal Science and Technology
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    • 제66권2호
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    • pp.266-278
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    • 2024
  • Antibiotic resistance (AR) is a complex, multifaceted global health issue that poses a serious threat to livestock, humans, and the surrounding environment. It entails several elements and numerous potential transmission routes and vehicles that contribute to its development and spread, making it a challenging issue to address. AR is regarded as an One Health issue, as it has been found that livestock, human, and environmental components, all three domains are interconnected, opening up channels for transmission of antibiotic resistant bacteria (ARB). AR has turned out to be a critical problem mainly because of the overuse and misuse of antibiotics, with the anticipation of 10 million annual AR-associated deaths by 2050. The fact that infectious diseases induced by ARB are no longer treatable with antibiotics foreshadows an uncertain future in the context of health care. Hence, the One Health approach should be emphasized to reduce the impact of AR on livestock, humans, and the environment, ensuring the longevity of the efficacy of both current and prospective antibiotics.

컨버전스 관점에서 미래 IPTV 서비스 변화와 정책이슈 전망 (Future IPTV Service's Shift and Policy Issues in Convergence Environments)

  • 이명순;이영희;김문선
    • 디지털융복합연구
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    • 제11권5호
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    • pp.13-21
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    • 2013
  • 방송통신 컨버전스의 대표 서비스인 IPTV는 21세기 국가 성장동력이 될 수 있는 무한한 잠재력을 지닌 분야이다. 미래지향적인 산업인만큼 IPTV 도입 정책은 근시안적인 시각에서 벗어나 중장기적인 관점에서 수립되는 것이 바람직하다. 이에 본 연구는 컨버전스 환경에서 미리 IPTV 서비스의 변화와 정책 이슈들을 제안하였다. 불확실한 미래의 상황을 예측, 분석하는 미래 연구이기 때문에 이러한 분석에 적합한 것으로 알려져 있는 T.A.I.D.A라는 연구 방법론을 분석에 활용하였다.

사무공간내의 공간통제, 공간융통성 및 산만함이 업무에 미치는 영향 (Interrelated effects of control, flexibility and distraction on work outcomes)

  • 이소영
    • 한국실내디자인학회논문집
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    • 제14권2호
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    • pp.135-141
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    • 2005
  • Subsequent to major changes in workplace such as communication method, uncertain organizational environment, and globalizaiton, several studies in workplace have explored the effects of those changes on work outcomes. Especially, employees need to have the balance in working alone and working with others. The purpose of this study is to examine the effects of control over the physical environment by individuals and the effects of flexibility on individual and group work outcomes in the workplace, to examine the effects of distraction on work outcomes, and to suggest a interrelationships among variables. In this study, four hundred and nine questionnaires were collected from employees of three manufacturing corporations in Michigan, U. S. In order to explore the causal interferences among multiple relationships suggested in this study, path analysis was employed using Lisrel 8.54. The results indicated that control over the physical environmental features of the workplace positively influenced job satisfaction. The findings also supported the hypothesis that flexibility is positively related to task group cohesiveness. It was found that distraction was negatively associated with control and flexibility. However, it was not supported that control was positively associated with perceived performance. This study found control and flexibility in the workplace to be important. Some practical implications were suggested emphasizing that control and flexibility allow limited resources to be used in ways that permit individuals to work effectively within a changing work environment.

사이버무역에서 중재의 역할과 온라인중재에 관한 연구 (A Study on the Roles of Arbitration and Online Arbitration in International Cyber Trade)

  • 오원석;유병욱
    • 한국중재학회지:중재연구
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    • 제14권1호
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    • pp.61-101
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    • 2004
  • Information and communications technologies are affecting an economic and social transformation of all countries. Without exception international commercial dispute resolution systems are faced with change its mechanism to online technology. Dispute parties can seek redress through arbitration other than litigation or mediation. Traditional dispute resolutions do not match the cyber trade environment which is basically pursuit the speed and efficiency in cyberspace. Arbitration other than resolution methods have been considered to be match with the online environment which is including party autonomy, speed and internationally accepted and binding awards. Traditional arbitration, however is lack of time and different physical location relating all parties. So we now think cyberspace as for the resolving place which is online arbitration. Even the parties exist in different space and time they may meet in the same time and space without moving or trips. Nowadays there are many online arbitration service provider serving the resolution of dispute arising with online transaction. In this paper we study the tendency for online arbitration, the recognize uncertain matters and avoiding programs its matters when use the online arbitration between disputing parties under cyber trade environment.

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인터넷 환경에서 힘반영을 이용한 이동로봇의 원격제어 (Internet-based Teleoperation of a Mobile Robot with Force-reflection)

  • 진태석;임재남;이장명
    • 제어로봇시스템학회논문지
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    • 제9권8호
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    • pp.585-591
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    • 2003
  • A virtual force is generated and fed back to the operator to make the teleoperation more reliable, which reflects the relationship between a slave robot and an uncertain remote environment as a form of an impedance. In general, for the teleoperation, the teleoperated mobile robot takes pictures of the remote environment and sends the visual information back to the operator over the Internet. Because of the limitations of communication bandwidth and narrow view-angles of camera, it is not possible to watch certain regions, for examples, the shadow and curved areas. To overcome this problem, a virtual force is generated according to both the distance between the obstacle and the robot and the approaching velocity of the obstacle w.r.t the collision vector based on the ultrasonic sensor data. This virtual force is transferred back to the master (two degrees of freedom joystick) over the Internet to enable a human operator to estimate the position of obstacle at the remote site. By holding this master, in spite of limited visual information, the operator can feel the spatial sense against the remote environment. It is demonstrated by experiments that this collision vector based haptic reflection improves the performance of teleoperated mobile robot significantly.

반응적시장지향성과 선제적시장지향성이 중소기업의 신제품 성과에 미치는 영향: 수출시장환경의 조절효과를 중심으로 (The Effects of RMO and PMO on SMEs' New Product Performance: The Moderating Role of Foreign Market Environment)

  • 이영우;조효은;정인식
    • 지식경영연구
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    • 제20권1호
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    • pp.175-194
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    • 2019
  • In order to overcome the limitation of market orientation concept, Narver et al. (2004) have extended the original concept into two dimensions, responsive market orientation (RMO) and proactive market orientation (PMO), respectively. Yet, there has been very limited empirical studies that analyzed the differential effects of each market orientation on firm outcomes, especially in the Korean context. We analyze the impact of RMO and PMO on the new product performance in the perspective of SMEs and examine the moderating effect of external factors such as environmental uncertainty and market similarity. The results of this study show that both RMO and PMO have a significant positive effect on the new product performance of SMEs. Also, environment uncertainty shows a negative moderating effect on the relationship between RMO and new product performance, whereas it has positive moderation with PMO. This suggests that focusing on potential customers' needs rather than current needs helps improve firm performance as the competitive environment surrounding the firm becomes more uncertain. Lastly, market similarity showed a positive moderating effect on the relationship between RMO and new product performance, but not on PMO.