Application of Grey Model Theory to Forecast Flight Training Time

2014 ◽  
Vol 635-637 ◽  
pp. 1696-1699
Author(s):  
Jun Wen ◽  
Hai Feng Duan ◽  
Shu Xia Sun ◽  
Ming Xing Li ◽  
Jian Fei Lv
Keyword(s):  
System Theory ◽  
Grey System Theory ◽  
Grey Model ◽  
Flight Training ◽  
Civil Aviation ◽  
Grey System ◽  
Short Term ◽  
Training Time ◽  
Forecast Result ◽  
High Prediction

Grey model GM(1,1) is applied to forecast flight training time. The discreteness of originality data is overcome and the high-precise predicted result is received under the condition of a small amount of data. This paper takes a short-term forecast flight training time of Civil Aviation Flight University of China (CAFUC) by using grey system theory. With a comparison of the actual data to the forecast result, it is proved that using grey system theory to forecast the flight training time of Civil Aviation Flight University of China is feasible with relatively high prediction accuracy.

Prediction of Technical Reserves Based on Grey Model — GM(1,1): Evidence from Non-life Egyptian Insurance Market

2019 ◽  
Vol 10 (9) ◽  
pp. 852-860
Author(s):  
Mahmoud Elsayed ◽  
◽  
Amr Soliman ◽  
Keyword(s):  
System Theory ◽  
Grey System Theory ◽  
Insurance Market ◽  
Grey Model ◽  
Loss Ratio ◽  
Grey System ◽  
Mathematical Technique ◽  
Supervisory Authority ◽  
Error Ratio ◽  
Using Data

Grey system theory is a mathematical technique used to predict data with known and unknown characteristics. The aim of our research is to forecast the future amount of technical reserves (outstanding claims reserve, loss ratio fluctuations reserve and unearned premiums reserve) up to 2029/2030. This study applies the Grey Model GM(1,1) using data obtained from the Egyptian Financial Supervisory Authority (EFSA) over the period from 2005/2006 to 2015/2016 for non-life Egyptian insurance market. We found that the predicted amounts of outstanding claims reserve and loss ratio fluctuations reserve are highly significant than the unearned premiums reserve according to the value of Posterior Error Ratio (PER).

scholarly journals Utilizing an Adaptive Grey Model for Short-Term Time Series Forecasting: A Case Study of Wafer-Level Packaging

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Che-Jung Chang ◽  
Der-Chiang Li ◽  
Wen-Li Dai ◽  
Chien-Chih Chen
Keyword(s):  
Semiconductor Manufacturing ◽  
Manufacturing System ◽  
Grey System Theory ◽  
Grey Model ◽  
Grey System ◽  
Wafer Level ◽  
Short Term ◽  
Packaging Process ◽  
Wafer Level Packaging

The wafer-level packaging process is an important technology used in semiconductor manufacturing, and how to effectively control this manufacturing system is thus an important issue for packaging firms. One way to aid in this process is to use a forecasting tool. However, the number of observations collected in the early stages of this process is usually too few to use with traditional forecasting techniques, and thus inaccurate results are obtained. One potential solution to this problem is the use of grey system theory, with its feature of small dataset modeling. This study thus uses the AGM(1,1) grey model to solve the problem of forecasting in the pilot run stage of the packaging process. The experimental results show that the grey approach is an appropriate and effective forecasting tool for use with small datasets and that it can be applied to improve the wafer-level packaging process.

Research and Application of Grey Predictive Model Based on Wavelet Analysis

2012 ◽  
Vol 170-173 ◽  
pp. 2912-2916
Author(s):  
Hai Ping Xiao ◽  
Lan Lan Chen ◽  
Yi Qiang Chen ◽  
Zhong Qun Guo
Keyword(s):  
System Theory ◽  
Wavelet Analysis ◽  
Predictive Model ◽  
Wavelet Transformation ◽  
Scientific Basis ◽  
Grey System Theory ◽  
Grey Model ◽  
Grey System ◽  
Predicting Model ◽  
Feasible Method

It is the scientific basis of instructing the project to produce and operate that the deformation is monitored, and the analysis and prediction in constructing and operating of project is one of the important jobs. In order to analyze and predict the deformation of the project more timely and accurately, the paper analyzed and established the feasibility of wavelet-grey predicting model on the basis of the grey system theory in modeling limitations and the characteristics of wavelet transformation. With the comparison of predictive datas in two kinds of models, the results show, the predictive datas of the wavelet-grey model are more accurately than grey model’s, and has achieved good results in prediction of the engineering, is a feasible method.

scholarly journals An Improved Nonequidistant Grey Model Based on Simpson Formula and Its Application

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhiming Hu ◽  
Chong Liu
Keyword(s):  
Prediction Accuracy ◽  
Prediction Models ◽  
Prediction Performance ◽  
Grey System Theory ◽  
Grey Model ◽  
Grey Prediction ◽  
Grey System ◽  
Proposed Model ◽  
Grey Models ◽  
High Prediction

Grey prediction models have been widely used in various fields of society due to their high prediction accuracy; accordingly, there exists a vast majority of grey models for equidistant sequences; however, limited research is focusing on nonequidistant sequence. The development of nonequidistant grey prediction models is very slow due to their complex modeling mechanism. In order to further expand the grey system theory, a new nonequidistant grey prediction model is established in this paper. To further improve the prediction accuracy of the NEGM (1, 1, t2) model, the background values of the improved nonequidistant grey model are optimized based on Simpson formula, which is abbreviated as INEGM (1, 1, t2). Meanwhile, to verify the validity of the proposed model, this model is applied in two real-world cases in comparison with three other benchmark models, and the modeling results are evaluated through several commonly used indicators. The results of two cases show that the INEGM (1, 1, t2) model has the best prediction performance among these competitive models.

scholarly journals Outlier Detection and Correction for the Deviations of Tooth Profiles of Gears

2013 ◽  
Vol 13 (2) ◽  
pp. 56-62
Author(s):  
Han Lianfu ◽  
Fu Changfeng ◽  
Wang Jun ◽  
Tang Wenyan
Keyword(s):  
System Theory ◽  
Outlier Detection ◽  
Grey System Theory ◽  
Grey Model ◽  
Grey System ◽  
Correction Model ◽  
Preprocessing Method ◽  
Simulation Results ◽  
Modeling Data

To decrease the influence of outlier on the measurement of tooth profiles, this paper proposes a method of outlier detection and correction based on the grey system theory. After studying the characteristics of outliers from the deviations of tooth profiles, this paper proposes a preprocessing method for the modeling data which include abnormal value, and establishes an outlier detection and correction model for the deviations of tooth profiles. Simulation results show that the precision of ONDGM(1,1)(one order and one variable non-homogenous discrete grey model whose outlier is processed by the preprocessing method proposed in this paper) is higher than that of NDGM(1,1)(one order and one variable non-homogenous discrete grey model), and the ONDGM(1,1) is more suitable than the NDGM(1,1) for dealing with the outliers from the deviations of tooth profiles. The experiment results show that the outlier detection and correction model detects and corrects the outliers from the deviations of tooth profiles, and the correction value of the outlier is basically in accordance with the actual deviation. Therefore, the method of outlier detection and correction decreases the influence of outlier and improves the precision in the measurement of tooth profiles.

Applications of Grey System Theory to Construction Control of Cable-Stayed Bridge

2010 ◽  
Vol 163-167 ◽  
pp. 2502-2506
Author(s):  
Fang Wen Wu ◽  
Cheng Feng Xue
Keyword(s):  
System Theory ◽  
Control Method ◽  
Grey System Theory ◽  
Grey Model ◽  
Construction Control ◽  
Grey System ◽  
Feedback Information ◽  
Technology System ◽  
Cable Stayed Bridge ◽  
Main Girder

Based on the grey system theory, and combined with the construction features of cable-stayed bridges and construction control method, the paper takes the cable-stayed bridge under construction as the interferential grey technology system with physical prototype and analyzes the random process as grey process in line with grey system theory. The grey model is established by the initialize heights of main girder and cables’ tension as two control inputs of system during the construction of the cable-stayed bridge. Through the feedback information and rectifying the grey model, the initialize heights of main girder and the cable force of next construction stage are predicted in order to control the bridge configuration and cable tension successfully.

scholarly journals Prediction and Optimization of Electrospun Polyacrylonitrile Fiber Diameter Based on Grey System Theory

Materials ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2237 ◽  
Author(s):  
Qihong Zhou ◽  
Liqun Lin ◽  
Ge Chen ◽  
Zhaoqun Du
Keyword(s):  
System Theory ◽  
Prediction Error ◽  
Fiber Diameter ◽  
Grey System Theory ◽  
Grey Prediction ◽  
Grey System ◽  
Average Prediction Error ◽  
Background Value ◽  
High Prediction ◽  
Fitting Error

This paper provides a new method for predicting the diameter of electrospun nanofibers. Based on the grey system theory, the effects of polyacrylonitrile mass fraction, voltage, flow rate, and receiving distance on fiber diameter were studied. The GM(1,1) (grey model) model and DNGM(1,1) (The DNGM (1,1) model is based on the whitening differential equation using parameters to Directly estimate the approximate Non-homogeneous sequence Grey prediction Model) model were established to predict fiber diameter by a single-factor change, and the results showed high prediction accuracy. The multi-variable grey model MGM(1,n) (MGM(1,n) is a Multivariate Grey prediction Model) was used for prediction of fiber diameter when multiple factors change simultaneously. The results showed that the average modeling fitting error is 8.62%. The background value coefficients of the MGM(1,n) model were optimized, the average modeling fitting error was reduced to 1.01%, and the average prediction error was reduced to 1.33%. Combining the fractional optimization with the background-value coefficient optimization, the optimal background-value coefficient α and the order r were selected. The results showed that the average modeling fitting error is 0.85%, and the average prediction error is 0.38%. The results demonstrate that the grey system theory can effectively predict the diameter of polyacrylonitrile electrospinning fibers with high prediction accuracy. This theory can increase the control of nanofiber diameters in production.

A grey-based assessment approach to the site selection of a desalination plant in Libya

2018 ◽  
Vol 8 (3) ◽  
pp. 366-379 ◽  
Author(s):  
Ibrahim A. Badi ◽  
Ali M. Abdulshahed ◽  
Ali Shetwan ◽  
Mohamed Ali Ballem
Keyword(s):  
System Theory ◽  
Site Selection ◽  
Grey System Theory ◽  
Grey Model ◽  
Grey System ◽  
Project Schedule ◽  
Content Type ◽  
Desalination Plant ◽  
A Site ◽  
Selection Of

Purpose The purpose of this paper is to propose a site selection method using grey system theory for a desalination plant in Libya. Design/methodology/approach In order to tackle incompleteness and imprecision of human’s judgments, grey numbers were used. This work uses a grey-based approach to represent decision makers’ comparison judgments and extent analysis method to select the best site. Therefore, a real case study of a selection problem of a site selection of desalination plant in Libya was used to illustrate the proposed approach. Findings Site selection in a desalination plant can be one of the most important decisions in planning a desalination project. The decision affects both the project cost and potentially the project schedule. Based on the results of grey model, a clear order of these sites and the degree of preference are obtained. This paper presents a way to improve a site selection by using a grey model, especially in a complex environment like Libya. Originality/value To the best knowledge of the authors, there is no literature for site selection using grey system theory in a desalination plant in Libya. This attempt may well enhance and facilitate the decision-making process of the best site in the country involved in this research.

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