In this paper analytical expression for determining the optimal parameter value of the Same Slope Seasonality model was developed. Then performance of the Same Slope Seasonality model was compared to the performance of Holt-Winters exponential model, performing tests on M2-Competition time series. To determine the parameters of Holt-Winters exponential model, nonlinear mathematical programming was used. Performed tests proved that Same Slope Seasonality model is more successful than Holt-Winters exponential model. Tests revealed that Same Slope Seasonality model gives unreliable forecasts when time series has specific charac teristics, giving us valuable information for model improvement.

Research is the viscoelasticity properties composite of wood made by gluing beech peeled veneer and at constant load, and two constant humidity. Based on the experimental results obtained by the method of the least squares rheological parameters have been determined as well as their differences in relation depending on the moisture content of samples. Has been developed and applied numerical model based on the finite volume method analysis of viscoelasticity properties composite of wood. Starting with the continuum concept we presented and broadened the application of the finite volume method for solving of the hygro-viscoelasticity behaviour of the composite of wood. Have been ignored of anisotropy in wood, and observation of the sample as homogenous, non-layered material, and also neglect of glue. We developed the constitutive relation including the impact of moisture, expressed through relaxation functions and given in integral form. The calculation results are compared with results of the experiment