isfahan province is located in the center of iran and has arid and semi-arid climate. in recent years, water shortage has increased in this region and has affected crop production. wheat is one of the most important crops of the province. in the present research, an index (dei) has been developed for drought evaluation using long term climatic data through application of principle components an...

This study demonstrates that a commonly used type of factor analysis, principle components analysis, contributes to the amount of error in statistical analysis. In the study, which concerns email use, factor analyses were performed using several different factor analysis methods. The results show that using factors derived via principle components analysis as dependent variables substantially i...

background: in its constitution of 1948, who defined health as “a state of complete physical, mental, and social well-being, and not merely the absence of disease and infirmity” . in 1994, the agency for health care policy and research published clinical practice guidelines recommending providers to routinely evaluate patients’ hrqol (health related quality of life) and use their assessment to ...

Approaches to approximate diagonalization of variable-coefficient differential operators using similarity transformations are presented. These diagonalization techniques are inspired by the interpretation of the Uncertainty Principle by Fefferman, known as the SAK Principle, that suggests the location of eigenfunctions of self-adjoint differential operators in phase space. The similarity transf...

this paper presents a combination of data envelopment analysis (dea) and principal component analysis (pca) to reduce the dimensionality of data set. dea is known as effective tool for assessment and benchmarking. the weak point of dea, it is that the number of efficient dmus relies on the number of variables (inputs and outputs). for solving this, first, we do principal component analysis (pca...