Count data with extra zeros are common in many medical applications. The zero-inflated Poisson (ZIP) regression model is useful to analyse such data. For hierarchical or correlated count data where the observations are either clustered or represent repeated outcomes from individual subjects, a class of ZIP mixed regression models may be appropriate. However, the ZIP parameter estimates can be s...

We deal with a two-queue model with mixed exhaustive and gated-type K-limited services. This model can achieve various degrees of priority in each queue by varying the value of K. Analyzing the model by using the delay cycle technique, we obtain the Laplace-Stieltjes transforms of the waiting time distributions for both cases with zero and non-zero walking times.

We study differentiable mixed-moment models (full zeroth and first moment, half higher moments) for a Fokker-Planck equation in one space dimension. Mixed-moment minimum-entropy models are known to overcome the zero net-flux problem of full-moment minimum entropy MN models. Realizability theory for these modification of mixed moments is derived for second order. Numerical tests are performed wi...

We develop a convex approximation for two-stage mixed-integer recourse models and we derive an error bound for this approximation that depends on all total variations of the probability density functions of the random variables in the model. We show that the error bound converges to zero if all these total variations converge to zero. Our convex approximation is a generalization of the one in C...

The main result of this paper is a generalization of the property that, for smooth u, uxy = 0 implies (*) u(x, y) = a(x) + b(y). Any function having generalized unsymmetric mixed partial derivative identically zero is of the form (*). There is a function with generalized symmetric mixed partial derivative identically zero not of the form (*), but (*) does follow here with the additional assumpt...

A general model for enzyme kinetics with inhibition, the “mixed” inhibition model, simplifies to the non-competitive inhibition model when two of the parameters are equal. We reparamaterise the model and provide designs for investigating the equality of parameters, which corresponds to a scalar parameter δ being zero. For linear models T-optimum designs for discriminating between models in whic...