In this paper,the Rama distribution(RD)is considered,and a new model called extended Rama distribution(ERD)is suggested.The new model involves the sum of two independent Rama distributed random variables.The probabili...In this paper,the Rama distribution(RD)is considered,and a new model called extended Rama distribution(ERD)is suggested.The new model involves the sum of two independent Rama distributed random variables.The probability density function(pdf)and cumulative distribution function(cdf)are obtained and analyzed.It is found that the new model is skewed to the right.Several mathematical and statistical properties are derived and proved.The properties studied include moments,coefficient of variation,coefficient of skewness,coefficient of kurtosis and moment generating function.Some simulations are undertaken to illustrate the behavior of these properties.In addition,the reliability analysis of the distribution is investigated through the hazard rate function,reversed hazard rate function and odds function.The parameter of the distribution is estimated based on the maximum likelihood method.The distributions of order statistics for ERD are also presented.The performance of the suggested model is compared with several other lifetime distributions based on some goodness of fit tests on a real dataset.It turns out that the suggested model is more flexible than its competitors considered in this study,for modeling real lifetime data.展开更多
In this study,the interaction between 3-D bedforms and submerged rigid vegetation has been investigated.Various laboratory experiments were conducted to study the distribution of flow velocity,Reynolds shear stress,tu...In this study,the interaction between 3-D bedforms and submerged rigid vegetation has been investigated.Various laboratory experiments were conducted to study the distribution of flow velocity,Reynolds shear stress,turbulent kinetic energy,and skewness coefficients for a constant density of vegetation.Results showed that the velocity profile in the pool section deviates from those in the upstream section of the pool.It has been found that the dip parameter varied between 0.6H and 0.9H depending on various factors including bed roughness,vegetation distribution,and pool entrance/exit slopes.However,scattered vegetation in the pool and differences in slopes created non-uniform flow conditions.Also,in the wake region behind each vegetated element,flow velocity reduced significantly,and small-scale eddies are formed,causing increased perturbations.By decreasing the entrance slope and bed roughness,relatively uniform flow and weaker turbulence was resulted,but the random distribution of vegetated elements counteracted this balance and intensified turbulence.With the decrease in the pool entrance slope,the contribution of sweep event decreased and the contribution of ejection event increased.展开更多
基金The authors extend their appreciation to Universiti Kebangsaan Malaysia for providing a partial funding for the work under the grant number GGPM-2017-124 and TAP-K017073 which were obtained by Mohd Aftar Abu Bakar.
文摘In this paper,the Rama distribution(RD)is considered,and a new model called extended Rama distribution(ERD)is suggested.The new model involves the sum of two independent Rama distributed random variables.The probability density function(pdf)and cumulative distribution function(cdf)are obtained and analyzed.It is found that the new model is skewed to the right.Several mathematical and statistical properties are derived and proved.The properties studied include moments,coefficient of variation,coefficient of skewness,coefficient of kurtosis and moment generating function.Some simulations are undertaken to illustrate the behavior of these properties.In addition,the reliability analysis of the distribution is investigated through the hazard rate function,reversed hazard rate function and odds function.The parameter of the distribution is estimated based on the maximum likelihood method.The distributions of order statistics for ERD are also presented.The performance of the suggested model is compared with several other lifetime distributions based on some goodness of fit tests on a real dataset.It turns out that the suggested model is more flexible than its competitors considered in this study,for modeling real lifetime data.
文摘In this study,the interaction between 3-D bedforms and submerged rigid vegetation has been investigated.Various laboratory experiments were conducted to study the distribution of flow velocity,Reynolds shear stress,turbulent kinetic energy,and skewness coefficients for a constant density of vegetation.Results showed that the velocity profile in the pool section deviates from those in the upstream section of the pool.It has been found that the dip parameter varied between 0.6H and 0.9H depending on various factors including bed roughness,vegetation distribution,and pool entrance/exit slopes.However,scattered vegetation in the pool and differences in slopes created non-uniform flow conditions.Also,in the wake region behind each vegetated element,flow velocity reduced significantly,and small-scale eddies are formed,causing increased perturbations.By decreasing the entrance slope and bed roughness,relatively uniform flow and weaker turbulence was resulted,but the random distribution of vegetated elements counteracted this balance and intensified turbulence.With the decrease in the pool entrance slope,the contribution of sweep event decreased and the contribution of ejection event increased.
