CHOICE OF FLEXIBLE FUNCTIONAL FORMS: REVIEW AND APPRAISAL

Choice between alternative flexible functional forms has received little explicit treatment in many empirical agricultural studies. Theoretical criteria and empirical techniques for choosing between flexible functional forms are reviewed. Theoretical topics include definitions of flexibility, mathematical expansions, separability, and regular regions. Empirical techniques examined are Monte Carlo analysis, parametric modeling, bayesian inference, and nonnested hypothesis testing. Comparison of the full range of theoretical and empirical aspects may provide more credible and reliable empirical estimates when consumer or producer duality assumptions are appropriate in agricultural applications.Research Methods/ Statistical Methods,

Threshold and power for Quantitative Trait Locus detection

We propose several new methods to calculate threshold and power for Quantitative Trait Locus (QTL) detection. They are based on asymptotic theoretical results presented in Rabier et al. (2009) . The asymptotic validity is checked by simulations. The methods proposed are fast and easy to implement. A comparison of power between a multiple testing procedure and a global test has been realized, showing far better performances of the global test for the detection of a QTL

Sustainability Assessment Methods for the Gulf Region

This paper describes the development of a sustainability assessment framework designed to be used in the Gulf Region, which is an area which has experienced large scale building development and also a region in which sustainability assessment is not yet widely used. The complexity and time resources needed to apply existing methods act as a deterrent to active use. Three well-known methods available at the time of the study were investigated in some detail. These were: BREEAM Gulf; Green Building Council LEED; and Estidama Pearl. Cross comparisons of the factors involved in each method were carried out on several levels including: theoretical comparison; practical development and usability; compliance with regulations and standards; and ability to achieve synchronization. A considerable degree of compatibility was found to exist between the methods, particularly if focused on key criteria. As a result a new and specific framework was developed which grouped 24 indicators under five principal headings: site/location, biodiversity and accessibility; energy; water; occupant well-being; and resources and wastes. This new framework was then evaluated by testing with practitioners resulting in confirmation of 20 out of the 24 indicators, and identification of suitable benchmarks

On Some Test Statistics for Testing the Population Skewness and Kurtosis: An Empirical Study

The purpose of this thesis is to propose some test statistics for testing the skewness and kurtosis parameters of a distribution, not limited to a normal distribution. Since a theoretical comparison is not possible, a simulation study has been conducted to compare the performance of the test statistics. We have compared both parametric methods (classical method with normality assumption) and non-parametric methods (bootstrap in Bias Corrected Standard Method, Efron’s Percentile Method, Hall’s Percentile Method and Bias Corrected Percentile Method). Our simulation results for testing the skewness parameter indicate that the power of the tests differs significantly across sample sizes, the choice of alternative hypotheses and methods we chose. For testing the kurtosis parameter, the simulation results suggested that the classical method performs well when the data are from both normal and beta distributions and bootstrap methods are useful for uniform distribution especially when the sample size is large

Mechanical Characterization and Shear Test Comparison for Continuous-Fiber Polymer Composites

As fiber-reinforced composites continue to be used in a wide-range of high performance structures, more detailed understanding and accurate prediction of stress-strain behaviour is necessary to improving designs and reducing costs. This thesis compares the experimental behaviour of a continuous fiber polymer composite of carbon fiber and epoxy resin using Digital Image Correlation to analytical and theoretical predictions. Furthermore, an in-depth analysis of shear testing methods reveals the advantages and limitations of different testing standards. Finally, the limitations of the Iosipescu Shear test (ASTM 5379) fixture to break high-strain-to-failure composites in comparison to the V-notched Rail Shear Fixture (ASTM 7078) is conclusively shown

Validation of Instrument Measuring Continuous Variable in Medicine

In medicine, accurate measurement of clinical values is vital, either at the stage of health screening, diagnosing cases or making prognosis. There are numerous instruments or machines that have been invented for the purpose of measuring various clinical variables such as blood pressure, glucose level, body temperature and oxygen level. When a new method of measurement or instrument is invented, the quality of the instrument has to be assessed. This chapter will focus on the application of statistical methods used to analyse continuous data in a method comparison study or validation study in medicine. The concept of validity and analysis in method comparison study will be discussed. This chapter also reviews the theoretical aspects of several common methods and approaches that have been used to measure agreement and reliability including the Bland-Altman limits of agreement (LoA) and intra-class correlation coefficient (ICC). Issues related to method comparison studies will be highlighted, which include the evaluation of agreement and reliability in a single study, the application of multiple statistical methods and the use of inappropriate methods in testing agreement and reliability. Finally, the importance of education in method comparison studies among medical professional will be emphasized