Papers by Keyword: Prediction Methods

Abstract: Rock burst is one of geological hazards encountered frequently, rock burst research has important significance for safety production in mine. The paper based on different definitions of rock burst, the produce conditions and manifestation of rock burst are summarized, and classified. The mechanism and prediction of rock burst in the mainstream view the advantage and disadvantages on comparison, a novel thought is given for rock burst mechanism. Suggest t to continue research on the mechanism of rock burst, and multi field coupling method to predict rock burst.

Abstract: In this study, a novel prediction method for electric power demand based on markov chain model with a fuzzy probability has been developed. The model improves upon the existing prediction methods with advantages in uncertainty reflection, such as the uncertainties in electric power system which reflect the vague and ambiguous during the process of power load forecasting through allowing uncertainties expressed as fuzzy parameters and discrete intervals. The developed model is applied to predict the electric power demand of a virtual city from 2011 to 2016. Different satisfaction degrees of fuzzy parameters are considered as different levels of detail of the statistic data. The results indicate that the model can reflect the high uncertainty of long term power demand, which could support the programming and management of power system.

Abstract: In order to improve the dynamical respond of the weighing system and to meet the demand of rapid weighing, a new method based on radial basis function neural network (RBFNN) is introduced in this paper. The dynamic system is described as a network and the output values of steady state are predicted by an on-line modeling before the platform has settled to the steady state. The sample weight is calculated according to weighted moving average. The experimental results proved that the neural network method in this paper can be used to effectively reduce the weighing time and to increase the accuracy simultaneously.

Abstract: Nowadays structure construction and monitoring, hazard forecasting depends more and more on scientific prediction methods. This paper focus on prediction method, which based on GM(1,1) model of Gary Theory. With a set of dynamic monitoring data from one structure, we introduce the modeling method of old information model, new information model and equal dimension new information model. An analysis of these prediction models reliability is performed to compare these models. The result of these models can predict the structure settlement proved that a suitable prediction method could provide help to structure safety and reduce unnecessary lost.

Abstract: An average creep rate conversion model based on Schlottner-Seeley creep assessment procedure and creep damage equation has been developed by considering the relationship that two stages of stress relaxation are corresponding to the first and the second creep stage respectively and the effect of these two kinds of creep rate on relaxation, and stress relaxation is creep at various stresses. And an incremental calculation prediction methodology of stress relaxation performance was established. The predicted results are compared with the data of stress relaxation tests conducted on bolting steel 1Cr10NiMoW2VNbN used in ultra-supercritical turbines. Validation results indicate that the developed model has led to better consistent results with the measured data and thus can be recommended in stress relaxation behavior prediction of high temperature materials.

Abstract: The prediction procedures of the residual stresses in welding process were presented by using finite element techniques. Owing to localized heating by the welding process and subsequent rapid cooling, the residual stresses can arise in the weld itself and in the base metals. The bilinear elastic-plastic material model based on Von Mises yield criterion was developed. The material nonlinearity of weldment and welding fluid was dealt with using an incremental technique. Inside each step, the Newton-Raphson iteration method was utilized. A fully coupled thermo-mechanical twodimensional analysis was performed with finite element method. The model applied in this study adopts the technique of element birth and death to simulate the weld filler variation with time in multi-pass welded joints. The effects of welding speed on residual stresses are discussed.

Abstract: Electromigration is one of the main damage mechanisms of interconnecting metal lines. Recently, a governing parameter for electromigration damage in passivated polycrystalline lines, AFD* gen, was formulated, and a prediction method for electromigration failure in passivated polycrystalline line was developed using AFD* gen. This method requires only the film characteristics of the metal line and the application is not limited by a line shape and operating condition. The usefulness of the method has been shown using the straight-shaped lines. Using the ymmetrically and asymmetrically angled lines experiments are performed, and the line-shape dependency of the lifetime obtained by the prediction method is verified comparing with the results obtained from the experiment.