Spelling suggestions: "subject:"linearregression"" "subject:"multilinearregression""
101 |
Coastline Simulation Using Fractalchuag, Yu-hua 08 July 2009 (has links)
Fractal was first used in measuring the length of the coastline, with the fractal
research and development, not only to break the traditional Archimedean geometry,
but also to explain many scientific to ignore the complexity and nature of nonlinear
phenomena structure .Fractal has been widely applied to such as physics, astronomy,
geography and sociology and other fields, as a wave of interdisciplinary research in
recent years. Coastal areas has always been cultural, economic and activities areas
since ancient times. Coastal zone was land and sea for the interaction region by a
variety of factors (ex: waves, tides, currents and wind, etc.) continue to function,
derived from different coastal terrain. Therefore changes in the coast of the deep
impact of humanity. Under the principle of the conservation and development,
Coastal areas should be use of modern technology to prediction, analysis, assessment,
planning, and management, so that a sustainable preservation of coastal resources.
In this study, static and dynamic predict and simulation the coast shape base on
fractal. The static part is observation of 29 beaches in South China coast. And collect
and calculate the parameters and fractal dimensions of the coast. Through the shape of
image processing and analysis of information, to find two generators of the coast.
Through the data mining technology to identify the criteria for classification, and to
simulation the coastline by generate iterations method. The dynamic part is based on
hydraulic model¡¦s results, the use of traditional multiple linear regression and neural
network to compare the dynamic prediction of the coastline. The results show that the
use of neural networks to predict than the use of multiple linear regression, and effect
of use difference angle (£c) to predict sub-coastlines than the effect of not use
difference angle (£c) to predict, and add fractal dimension can effectively reduce the
predict error and increase the degree of interpretation.
|
102 |
Analysis of Billet Surface-Permeation and Extrusion Die Shape Design During Rod Extrusion ProcessesChen, Jian-Ming 01 September 2009 (has links)
During a rod extrusion process, the oxidation layer and the segregation layer at the billet surface are possibly drawn inside the billet and become one part of the product, which portion with surface-permeation has to be cut off and results in a low productivity of the extrusion process. In this paper, the mechanism of permeation of the oxidation and segregation layers at the billet surface is explored using a finite element analysis. The effects of various extrusion conditions, such as extrusion ratio, inclination angle, billet length, the thickness of oxidation layer, etc., on the length of the portion with surface permeation are discussed systematically. Optimal inclination angles for a free surface-permeation product under different extrusion ratios are found out. An empirical equation for the optimal inclination angles is also proposed. Finally, experiments of extrusion of aluminum rods are conducted to validate the analytical model proposed.
|
103 |
The Credibility Study of Ocean Ambient Noise Prediction EquationWang, Chien-Jen 09 September 2009 (has links)
Ocean Ambient Noise covers wide range except target signal in the sonar equation and is an influential parameter in sonar performance. Empirical equation obtained from linear regression of wind speed and ambient noise data is a common method to predict the noise level. Both ambient noise and wind speed data collected from experiments in southwest and northeast Taiwan sea were analyzed in statistics and time series. Experiment data was also used for prediction equations and further analysis. Coefficient of determination (r2) and F-test for the slope of the regression line were used to estimate how noise fit with wind speed data and the credibility of the regression. The result of the analysis was that the distribution of r2 changes with regions. The values of r2 calculated from northeast experiment data are higher than southwest because of the high percentage of high wind speed. The data from the northeast experiment is considered more appropriate for the prediction of noise level because the higher value of r2. All results of F-test showed the correlation between wind speed are statistically significant except the winter data in the southwest experiment. By using these two indicators, the credibility of the prediction equation can be realized and the prediction performance of sonar is promoted.
|
104 |
An Empirical Study on Housing Price in China Under Macro Control Measures石淑慧, Shih, Shu-Hui Unknown Date (has links)
The price of real estate is the result of economical operation and, most importantly, regulation mechanism of resource distribution for real estate industry. Since the process of economic reform began in 1978, there have been several times that the Chinese government imposed contractive measures intended to slow down the economic growth. This paper applies insights from economic theory to explain recent housing price patterns in China’s four largest metropolitan areas. (Beijing, Shanghai, Shenzhen and Guangzhou) and discusses how the Chinese Government’s stance and policy affect the development of real estate. By examining the degree of impact on the housing market as a result of Macro Control Measures, excluding other housing market drivers; the empirical results revealed the degree of effectiveness by the Chinese Government administrative control over the housing market vary across the regions.
|
105 |
Hepatic Gene Expression Profiling to Predict Future Lactation Performance in Dairy CattleDoelman, John 07 October 2011 (has links)
An experiment was conducted to obtain a hepatic gene expression dataset from postpubertal dairy heifers that could be fit to a computational model capable of predicting future lactation performance values. The initial animal experiment was conducted to characterize the hepatic transcriptional response to 24-hour total feed withdrawal in one-hundred and two postpubertal Holstein dairy heifers using an 8329-gene oligonucleotide microarray in a randomized block design. Plasma concentration of non-esterified fatty acids was significantly higher, while levels of beta-hydroxybutyrate, triacylglycerol, and glucose were significantly lower with the 24-hour total feed withdrawal. In total, 505 differentially expressed genes were identified and microarray results were confirmed by real-time PCR. Upregulation of key gluconeogenic genes occurred despite diminished dietary substrate and lower hepatic glucose synthesis. Downregulation of ketogenic genes was contrary to the non-ruminant response to feed withdrawal, but was consistent with a lower ruminal supply of short-chain fatty acids as precursors. Following the microarray experiment, the first series of regression analyses was employed to identify relationships between gene expression signal and lactation performance measurements taken over the first lactation of 81 of the subjects from the original study. Regression models were evaluated using mean square prediction error (MSPE) and concordance correlation coefficient (CCC) analysis. The strongest validated stepwise regression models were constructed for milk protein percentage (r = 0.04) and lactation persistency (r = 0.09). To determine if another type of regression analysis would better predict lactation performance, partial least squares (PLS) regression analysis was then applied. Selection of gene expression data was based on an assessment of the linear dependence of all genes in normalized datasets for 81 subjects against 18 dairy herd index (DHI) variables using Pearson correlation analysis. Results were distributed into two lists based on correlation coefficient. Each gene expression dataset was used to construct PLS models for the purpose of predicting lactation performance. The strongest predictive models were generated for protein percentage (r = 0.46), 305-d milk yield (r = 0.44), and 305-d protein yield (r = 0.47). These results demonstrate the suitability of using hepatic gene expression in young animals to quantitatively predict future lactation performance. / Ontario Centre for Agricultural Genomics, NSERC Canada, and the Ontario Ministry of Agriculture, Food and Rural Affairs (OMAFRA)
|
106 |
Statistical analysis of L1-penalized linear estimation with applicationsÁvila Pires, Bernardo Unknown Date
No description available.
|
107 |
Spatial methods in econometricsGumprecht, Daniela 05 1900 (has links) (PDF)
This thesis deals with the appropriate handling of spatial data in general, and in particular in the framework of economic sciences. An overview of well known methods from the field of spatial statistics and spatial econometrics is given. Furthermore a special class of spatial objects is described, namely objects that are that far apart from all other observations in the dataset, that they are not connected to them anymore. Different treatments of such objects are suggested and their influence on the Moran's I test for spatial autocorrelation is analyzed in more detail. After this theoretical part some adequate spatial methods are applied to the well-known problem of R&D spillovers. The corresponding dataset is not obviously spatial, nevertheless spatial methods can be used. The spatial contiguity matrix is based on an economic distance measure instead of the commonly used geographic distances. Finally, optimal design theory and spatial analysis are combined via a new criterion. This criterion was developed to be able to take a potential spatial dependency of the data points into account. The aim is to find the best design points that show the same spatial dependence structure as the true population. (author's abstract)
|
108 |
Robust techniques for regression models with minimal assumptions / M.M. van der WesthuizenVan der Westhuizen, Magdelena Marianna January 2011 (has links)
Good quality management decisions often rely on the evaluation and interpretation of data. One of the most popular ways to investigate possible relationships in a given data set is to follow a process of fitting models to the data. Regression models are often employed to assist with decision making. In addition to decision making, regression models can also be used for the optimization and prediction of data. The success of a regression model, however, relies heavily on assumptions made by the model builder. In addition, the model may also be influenced by the presence of outliers; a more robust model, which is not as easily affected by outliers, is necessary in making more accurate interpretations about the data. In this research study robust techniques for regression models with minimal assumptions are explored. Mathematical programming techniques such as linear programming, mixed integer linear programming, and piecewise linear regression are used to formulate a nonlinear regression model. Outlier detection and smoothing techniques are included to address the robustness of the model and to improve predictive accuracy. The performance of the model is tested by applying it to a variety of data sets and comparing the results to those of other models. The results of the empirical experiments are also presented in this study. / Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2011.
|
109 |
Robust techniques for regression models with minimal assumptions / M.M. van der WesthuizenVan der Westhuizen, Magdelena Marianna January 2011 (has links)
Good quality management decisions often rely on the evaluation and interpretation of data. One of the most popular ways to investigate possible relationships in a given data set is to follow a process of fitting models to the data. Regression models are often employed to assist with decision making. In addition to decision making, regression models can also be used for the optimization and prediction of data. The success of a regression model, however, relies heavily on assumptions made by the model builder. In addition, the model may also be influenced by the presence of outliers; a more robust model, which is not as easily affected by outliers, is necessary in making more accurate interpretations about the data. In this research study robust techniques for regression models with minimal assumptions are explored. Mathematical programming techniques such as linear programming, mixed integer linear programming, and piecewise linear regression are used to formulate a nonlinear regression model. Outlier detection and smoothing techniques are included to address the robustness of the model and to improve predictive accuracy. The performance of the model is tested by applying it to a variety of data sets and comparing the results to those of other models. The results of the empirical experiments are also presented in this study. / Thesis (M.Sc. (Computer Science))--North-West University, Potchefstroom Campus, 2011.
|
110 |
A Temporal Neuro-fuzzy Approach For Time Series AnalysisSisman Yilmaz, Nuran Arzu 01 January 2003 (has links) (PDF)
The subject of this thesis is to develop a temporal neuro-fuzzy system for fore-
casting the future behavior of a multivariate time series data.
The system has two components combined by means of a system interface.
First, a rule extraction method is designed which is named Fuzzy MAR (Multivari-
ate Auto-regression). The method produces the temporal relationships between
each of the variables and past values of all variables in the multivariate time series
system in the form of fuzzy rules. These rules may constitute the rule-base in a
fuzzy expert system.
Second, a temporal neuro-fuzzy system which is named ANFIS unfolded in -
time is designed in order to make the use of fuzzy rules, to provide an environment
that keeps temporal relationships between the variables and to forecast the future
behavior of data. The rule base of ANFIS unfolded in time contains temporal
TSK(Takagi-Sugeno-Kang) fuzzy rules. In the training phase, Back-propagation
learning algorithm is used. The system takes the multivariate data and the num-
ber of lags needed which are the output of Fuzzy MAR in order to describe a
variable and predicts the future behavior.
Computer simulations are performed by using synthetic and real multivariate
data and a benchmark problem (Gas Furnace Data) used in comparing neuro-
fuzzy systems. The tests are performed in order to show how the system efficiently
model and forecast the multivariate temporal data. Experimental results show
that the proposed model achieves online learning and prediction on temporal data.
The results are compared by other neuro-fuzzy systems, specifically ANFIS.
|
Page generated in 0.0572 seconds