• Title/Summary/Keyword: Forward model

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A Study on Uncertainty Analyses of Monte Carlo Techniques Using Sets of Double Uniform Random Numbers

  • Lee, Dong Kyu;Sin, Soo Mi
    • Architectural research
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    • v.8 no.2
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    • pp.27-36
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    • 2006
  • Structural uncertainties are generally modeled using probabilistic approaches in order to quantify uncertainties in behaviors of structures. This uncertainty results from the uncertainties of structural parameters. Monte Carlo methods have been usually carried out for analyses of uncertainty problems where no analytical expression is available for the forward relationship between data and model parameters. In such cases any direct mathematical treatment is impossible, however the forward relation materializes itself as an algorithm allowing data to be calculated for any given model. This study addresses a new method which is utilized as a basis for the uncertainty estimates of structural responses. It applies double uniform random numbers (i.e. DURN technique) to conventional Monte Carlo algorithm. In DURN method, the scenarios of uncertainties are sequentially selected and executed in its simulation. Numerical examples demonstrate the beneficial effect that the technique can increase uncertainty degree of structural properties with maintaining structural stability and safety up to the limit point of a breakdown of structural systems.

Dynamic Analysis and Control Design of Current-Mode Controlled Active-Clamp Forward-Flyback Converter (전류제어 능동 클램프 포워드-플라이백 컨버터의 동특성 해석 및 제어회로 설계)

  • Lim, Won-Seok;Kang, Young-Han;Choi, Byung-Cho
    • Proceedings of the KIPE Conference
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    • 2002.07a
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    • pp.374-377
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    • 2002
  • This paper presents dynamic analyses and control design of the current-mode controlled active-clamp forward-flyback converter. The circuit averaging technique is used to extract the small-signal circuit model for the power stage From the small-signal circuit model of the power stage, the open-loop transfer functions are derived and used for the compensation design. The analysis results are verified using an experimental converter that delivers a 3.3V/10A output from a $40\~60V$ input source.

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Performance Analysis of Nonlinear Energy-Harvesting DF Relay System in Interference-Limited Nakagami-m Fading Environment

  • Cvetkovic, Aleksandra;Blagojevic, Vesna;Ivanis, Predrag
    • ETRI Journal
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    • v.39 no.6
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    • pp.803-812
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    • 2017
  • A decode-and-forward system with an energy-harvesting relay is analyzed for the case when an arbitrary number of independent interference signals affect the communication at both the relay and the destination nodes. The scenario in which the relay harvests energy from both the source and interference signals using a time switching scheme is analyzed. The analysis is performed for the interference-limited Nakagami-m fading environment, assuming a realistic nonlinearity for the electronic devices. The closed-form outage probability expression for the system with a nonlinear energy harvester is derived. An asymptotic expression valid for the case of a simpler linear harvesting model is also provided. The derived analytical results are corroborated by an independent simulation model. The impacts of the saturation threshold power, the energy-harvesting ratio, and the number and power of the interference signals on the system performance are analyzed.

Promotion of Agricultural Technology Innovations for the Poor Smallholders in Marginal Rural Areas of Bangladesh: An Innovative Business Model Approach

  • Mohammad, Ikhtiar;Malek, Mohammad Abdul
    • Asian Journal of Innovation and Policy
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    • v.6 no.1
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    • pp.58-84
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    • 2017
  • This article aims at demonstrating location specific approach for agricultural technology promotion and adoption in improving the livelihood of the small farmers in the haor basin and coastal belt of Bangladesh. Innovative technologies that have potentials are initially screened by ex-ante investigation and instrumented by the business model canvas, which is used as a bottom-up approach for sustainability of the adoption of proposed technology innovations. Village-level extension farmers, sub-district extension officers and farmers' cooperative are the unique and central features to the business models and forward linkages. Extension service, power tiller, low-lift pump, sunflower, shallow tube well, quality seed, forward linkage for farmed duck eggs, live ducks and open catch fish etc. are the suggested potential technology innovations for the small farmers. The technology adoption business model can be reinvented for different locations within or beyond the country considering the local agricultural problems and prospects for greater sustainability.

Modeling, Identification and Control of a Redundant Planar 2-DOF Parallel Manipulator

  • Zhang, Yao-Xin;Cong, Shuang;Shang, Wei-Wei;Li, Ze-Xiang;Jiang, Shi-Long
    • International Journal of Control, Automation, and Systems
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    • v.5 no.5
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    • pp.559-569
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    • 2007
  • In this paper, the dynamic controller design problem of a redundant planar 2-dof parallel manipulator is studied. Using the Euler-Lagrange equation, we formulate the dynamic model of the parallel manipulator in the joint space and propose an augmented PD controller with forward dynamic compensation for the parallel manipulator. By formulating the controller in the joint space, we eliminate the complex computation of the Jacobian matrix of joint angles with end-effector coordinate. So with less computation, our controller is easier to implement, and a shorter sampling period can be achieved, which makes the controller more suitable for high-speed motion control. Furthermore, with the combination of static friction model and viscous friction model, the active joint friction of the parallel manipulator is studied and compensated in the controller. Based on the dynamic parameters of the parallel manipulator evaluated by direct measurement and identification, motion control experiments are implemented. With the experiments, the validity of the dynamic model is proved and the performance of the controller is evaluated. Experiment results show that, with forward dynamic compensation, the augmented PD controller can improve the tracking performance of the parallel manipulator over the simple PD controller.

Estimating Neuro-Pathway from Visual and Somatosensory Evoked Potential (유발전위를 이용한 뇌의 시감각 및 체성감각 인지영역 추정기술)

  • 배병훈;김동우
    • Journal of Biomedical Engineering Research
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    • v.15 no.4
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    • pp.481-488
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    • 1994
  • In this paper a study of neuro-pathway estimation based on visual and somatosensory evoked potential is given. The evoked potentials which are caused by visual and somatosensory stimulation are detected by an average method. The forward problem that is estimating a scalp potential from a given electrical source in the brain is solved by using a triple concentric spherical shell model of the head and a single current dipole model of the neuron activity. The inverse problem which calculates a source position is solved by a least square fit between the model predicted potential and a given evoked potential measurement. The similarities between estimated sensory neuro-pathways and physiological brain function regions are verified.

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Node Incentive Mechanism in Selfish Opportunistic Network

  • WANG, Hao-tian;Chen, Zhi-gang;WU, Jia;WANG, Lei-lei
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.3
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    • pp.1481-1501
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    • 2019
  • In opportunistic network, the behavior of a node is autonomous and has social attributes such as selfishness.If a node wants to forward information to another node, it is bound to be limited by the node's own resources such as cache, power, and energy.Therefore, in the process of communication, some nodes do not help to forward information of other nodes because of their selfish behavior. This will lead to the inability to complete cooperation, greatly reduce the success rate of message transmission, increase network delay, and affect the overall network performance. This article proposes a hybrid incentive mechanism (Mim) based on the Reputation mechanism and the Credit mechanism.The selfishness model, energy model (The energy in the article exists in the form of electricity) and transaction model constitute our Mim mechanism. The Mim classifies the selfishness of nodes and constantly pay attention to changes in node energy, and manage the wealth of both sides of the node by introducing the Central Money Management Center. By calculating the selfishness of the node, the currency trading model is used to differentiate pricing of the node's services. Simulation results show that by using the Mim, the information delivery rate in the network and the fairness of node transactions are improved. At the same time, it also greatly increases the average life of the network.

Does Inward Foreign Direct Investments Affect Export Performance of Micro Small and Medium Enterprises in India? An Empirical Analysis

  • SINGHA, Seema;KUMAR, Brajesh;CHOUDHURY, Soma Roy Dey
    • The Journal of Asian Finance, Economics and Business
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    • v.9 no.9
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    • pp.143-156
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    • 2022
  • This article examines the effect of inward foreign direct investments (FDI) on the export performance of micro, small & medium enterprises (MSMEs) in India, and investigates the spillover impact and absorption capacity of the MSMEs sector. For the first time, the researchers applied the intersectoral linkage approach to investigate the matter and used a panel dataset between 2006 and 2017. The coefficients of forward and backward linkages are estimated by using the Rasmussen method, the study employs a basic linear panel data model, followed by various diagnostic tests to identify the problem of heteroscedasticity, autocorrelation / serial correlation, cross-sectional dependencies, multicollinearity, time-individual specific tests, and unobserved effects. The PCSE model was applied for robust standard error and the Hausman-Taylor IV model to check the robustness of the result generated in the linear panel data model. Despite the high prevalence of forward and backward intersectoral connections and the Lack of absorption capacity of local firms, the results show that FDI has little of an impact on the export performance of micro, small, and medium-sized businesses in India. This study adds to the existing literature on determining local firms' spillover effect and absorption capacity in response to inward FDI.

Model for the prediction of Roll Force of Roughing Mill considering Width reduction (도그본 고려한 조압연 압연하중 예측모델 개발)

  • Kwak, W.J.;Lee, S.J.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2007.05a
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    • pp.223-225
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    • 2007
  • Online models predicting roll force and forward slip of roughing mill was developed using nondimensional parameters. Using the effective inlet thickness, roll force model take into account the effect of inlet dog-bone shape of slab which take places after width reduction through edger rolling in roughing mill. The prediction accuracy of the proposed model is examined through comparison with measurements.

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Time to change from a simple linear model to a complex systems model

  • Hong, Yun-Chul
    • Environmental Analysis Health and Toxicology
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    • v.31
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    • pp.8.1-8.2
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    • 2016
  • A simple linear model to test the hypothesis based on one-on-one relationship has been used to find the causative factors of diseases. However, we now know that not just one, but many factors from different systems such as chemical exposure, genes, epigenetic changes, and proteins are involved in the pathogenesis of chronic diseases such as diabetes mellitus. So, with availability of modern technologies to understand the intricate nature of relations among complex systems, we need to move forward to the future by taking complex systems model.