Tomasz Haniszewski

A comparison of forecasting the results of road transportation needs

Abstract Determining the size and quality of transport needs would not be possible without adequate forecasting based on the sales volume or demand for this service from the past periods. Traditional forecasting methods use econometric models that may be subject to serious errors. The use of the methods taking into account the variability of the studied phenomena or more advanced mathematical methods enables to minimize the error. Various methods of artificial intelligence such as a neural network, fuzzy sets, genetic algorithms, etc., have been recently successfully applied. The aim of this paper is to compare three forecasting methods that can be used for predicting the volume of road freight. The article deals with the effectiveness of three prediction methods, namely Winters method for seasonal problems – a multiplicative version, harmonic analysis and harmonic analysis aided by the artificial immune system. The effectiveness of prediction was counted using MAPE errors (main average percentage error)...

Numerical Modelling of I-Beam Jib Crane with Local Stresses in Wheel Supporting Flanges - Influence of Hoisting Speed

This article presents an approach of numerical modelling of I-beam crane jib, with using the finite element method particularly the most loaded elements at different speeds. One of the possible methods for use in the design process of hoisting dynamics modelling and its effects on the load-carrying structure for the marine jib crane is shown. For proper modelling, the impact of the load and hoisting speed on the load-carrying structure jib, dynamics simulations of hoisting the load using Matlab-Simulink software were carried out and in the field of finite element method. To carry out such a simulation, hybrid calculations had to be applied, where the response from the phenomenological model based on solving a system of differential equations of motion in Matlab-Simulink was used to stimulate the crane I-beam jib during the FEM simulation, which permits to determine dynamic properties of the load-carrying structure for two example different hoisting speeds. The basic strength parameters for a typical light marine jib crane, obtained in the case of static calculations and using the proposed approach between the two computing environments were compared.