An integrated production planning model for molds and end items

This study develops a mathematical modelling framework for simultaneously generating production plans for molds and the end items that are made with them. The inputs considered are the item demand (assumed constant over an infinite planning horizon), holding costs and shortage costs, together with the molds’ statistical lifetime distribution (in terms of number of uses) and costs pertaining to amortization, preventive replacements and corrective replacements.     

On the Instability of Tunisian Money Demand: Some Empirical Issues with Structural Breaks

This paper focuses on the causes of instability of money demand in Tunisia between 1973 and 2013. It has been argued that the main explanatory factors of money demand are national income, monetary market rate and exchange rate. We tested Ambler and McKinnon hypothesis (1985), which assumes that instability is explained by the absence of the nominal exchange rate in the specification of money demand. We found that structural changes are explained by the dependence of the national economy to world shocks, the IMF’s structural adjustment programme at the end of 1986.

     

A decision model for adopting an extended warranty under different maintenance policies

Numerous products are sold with a warranty period and the possibility of buying an extended warranty for a given additional cost. The buyer has then to decide to take the extended warranty or not when purchasing the product. We develop in this paper a mathematical model to study the opportunity provided by the extended warranty for the buyer as well as for the manufacturer. The total average cost incurred by each side during the product’s life cycle is expressed in order to determine the maximum extra cost the consumer should pay and the minimum price at which the manufacturer should sell the extended warranty. This is done under different options in terms of maintenance strategies adopted during the product’s lifecycle.