• East Asian Economic Review
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• v.28 no.1
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• pp.95-140
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• 2024

This study empirically investigates the international transmission of China's uncertainty shocks. It estimates a time-varying parameter Bayesian global structural vector autoregressive model (TVP-BGVAR) using time series data for 33 countries to evaluate heterogeneous international linkage across countries and time. Uncertainty shocks are identified via sign restrictions. The empirical results reveal that an increase in uncertainty in China negatively affects the global economy, but those effects significantly vary over time. The effects of China's uncertainty shocks on the global economy have been significantly altered by China's WTO accession, the global financial crisis, and the recent US-China trade conflict. Furthermore, the effects of China's uncertainty shocks, typically on inflation, differ significantly across countries. Moreover, Trade openness appears crucial in explaining heterogeneous GDP responses across countries, whereas the international dimension of monetary policy appears to be important in explaining heterogeneous inflation responses across countries.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.2941-2959
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• 2022

The fire brigade non-suppression probability model is a major factor that should be considered in evaluating fire-induced risk through fire probabilistic risk assessment (PRA), and also uncertainty is a critical consideration in support of risk-informed performance-based (RIPB) fire protection decision-making. This study developed an optimal integrated probabilistic fire brigade non-suppression model considering uncertainty of parameters based on the Bayesian Markov Chain Monte Carlo (MCMC) approach on electrical fire which is one of the most risk significant contributors. The result shows that the log-normal probability model with a location parameter (µ) of 2.063 and a scale parameter (σ) of 1.879 is best fitting to the actual fire experience data. It gives optimal model adequacy performance with Bayesian information criterion (BIC) of -1601.766, residual sum of squares (RSS) of 2.51E-04, and mean squared error (MSE) of 2.08E-06. This optimal log-normal model shows the better performance of the model adequacy than the exponential probability model suggested in the current fire PRA methodology, with a decrease of 17.3% in BIC, 85.3% in RSS, and 85.3% in MSE. The outcomes of this study are expected to contribute to the improvement and securement of fire PRA realism in the support of decision-making for RIPB fire protection programs.

• Korean Journal of Adult Nursing
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• v.17 no.5
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• pp.743-752
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• 2005

Purpose: The purposes of this study were to identify the level of total symptom distress, uncertainty, depression and ways of coping in women with endometriosis based on Mishel's model of Uncertainty in Chronic illness, and to exam the relationships among symptom distress, depression and ways of coping and the mediating effect of ways of coping between uncertainty and depression. Method: The research was used for correlational research design and data were collected with 123 women with endometriosis who live in a local area by convenience sampling. Results: The finding showed that the levels of symptom distress and uncertainty were moderate and the depression was above the middle level. There were positive relationships among symptom distress, uncertainty and depression but a negative relationship between problem focused coping and depression. The significant predictors for depression were symptom distress, uncertainty, and problem focused coping with 40% of explained variance. Problem focused coping showed mediating effect between uncertainty and depression. Conclusion: Therefore, nursing intervention for the strategy of increasing problem focused coping as well as lowering uncertainty and depression is recommended. Further study is needed to conduct a repetitive study with randomized nationwide population and to evaluate the theory with different outcomes for adaptation versus maladaptation.

• Journal of Environmental Policy
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• v.8 no.3
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• pp.163-180
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• 2009

This study attempts to investigate the preference uncertainty of respondents involved in stating their Willingness to Pay (WTP). For the Contingent Valuation Method (CVM) survey, we employed two approaches using two split samples. The respondents of one sample were given the opportunity to express intensity of preference through Multi-bounded Discrete Choice (MBDC) WTP questions, while those in the other sample were given Dichotomous Choice (DC) WTP questions. By incorporating the two elicited degrees of preference uncertainty into examining the WTP responses, we compared the two approaches. In comparing the DC model with the MBDC model, the mean WTP for the DC model was similar to PRYES in the MBDC Model. We concluded that the MBDC model estimates the various mean WTP while considering the preference uncertainty.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.11
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• pp.1051-1058
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• 2011

The military communication equipment is required the high reliability for operating adequate functions under severe conditions. This reliability is the essential element for the quality of the product, for the uncontrolled factors, such as the clearance, damage of the material, the reduction of stiffness, which are the designer is unable to handle. In this paper, the uncertainty for the dimension was supposed to the probability model for the military communication equipment, and the average of the objective function was minimized for reducing design uncertainty. The reliability-based design optimization which was implemented the limit state function was formulated into the mathematical model, so the reliable optimized structure was implemented than the base-line design.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1388-1392
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• 2008

Water resources management depends on dealing inherent uncertainties stemming from climatic and hydrological inputs and models. Dealing with these uncertainties remains a challenge. Streamflow forecasts basically contain uncertainties arising from model structure and initial conditions. Recent enhancements in climate forecasting skill and hydrological modeling provide an breakthrough for delivering improved streamflow forecasts. However, little consideration has been given to methodologies that include coupling both multiple climate and multiple hydrological models, increasing the pool of streamflow forecast ensemble members and accounting for cumulative sources of uncertainty. The approach here proposes integration and coupling of global climate models (GCM), multiple regional climate models, and numerous hydrological models to improve streamflow forecasting and characterize system uncertainty through generation of ensemble forecasts.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.11
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• pp.920-929
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• 2005

This paper presents controller design method for nonlinear radar gimbal system with parameter uncertainty and time delay. In order to consider nonlinearity of gimbal bearing frictional torque, we firstly represent fuzzy model for the nonlinear gimbal system, which is achieved by fuzzy combination of linear models through nonlinear fuzzy membership functions. And secondly we propose a delay dependent fuzzy $H_\infty$ controller design method for the delayed fuzzy model with parameter uncertainty and design radar gimbal controller. The designed controller stabilize gimbal system and guarantee $H_\infty$ performance. A computer simulation is given to illustrate stabilized control performances of the designed controller.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.826-829
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• 2008

In a field measurement, measurement errors are produced by measuring environments and systematic errors in the measurement procedure. Measurement errors can be expressed as a measurement uncertainty. In this study, the measurement uncertainty and various measuring factors are investigated in heavy-weight impact sounds. According to KS 2810-2, the model functions, which is the estimation of the maximum SPL measurement in each octave band frequency, are determined. From this estimation model, 3.53dB is shown in 63Hz. This level is caused by the sound field of the receiving room, which does not meet the diffusing field.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.3
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• pp.270-276
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• 2014

This survey paper reviews robust control problems in both frequency domain and time domain. Robust control is focused on model uncertainties such as modeling error, system parameter variations, and disturbances. Robust control design problems are discussed according to parameter uncertainty, polytopic uncertainty, and norm-bounded uncertainty. Nowadays, robust control theory is combined with various control theory such as model predictive control, adaptive control, intelligent control, and time delay control.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.504-509
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• 2011

The military communication equipment is required the high reliability for operating adequate functions under severe conditions. This reliability is the essential element for the quality of the product, for the uncontrolled factors, such as the clearance, damage of the material, the reduction of stiffness, which are the designer is unable to handle. In this paper, the uncertainty for the design was supposed to the probability model for the military communication equipment, and the average of the objective function was minimized for reducing design uncertainty. The reliability-based design optimization which was implemented the limit state function was formulated into the mathematical model, so the reliable optimized structure was implemented than the base-line design.