The nuclear (supernormal) cones were introduced by the regretted Professor George Isac (1981) and published in 1983. With his permission and for the first time we named them 'Isac's cones' in 2009. In memory of Professor Isac, we present some considerations of noticeable importance on this class...

Companies typically plan for warranty costs through creation of a reserve fund. Most researchers assume that the warranty reserve is set based on the expected total warranty costs. However, companies rarely keep reserves to cover their liabilities for the whole life of their products, since...

This paper is a response to reports by a number of authors of difficulties in using feedforward neural networks (NNs) in the presence of seasonality. Such difficulties appear to contradict the well-known property of 'universal approximation', but arise in fact because the property only applies...

There is a wide literature about the behaviour of agents in a stock-market in the presence of imitation phenomena. Some issues may be treated in a game-theory context. In particular, we consider a micro-model of stock-market speculator and formalise it in a Stackelberg game. The problem consists...

This paper presents a water supply problem arising from the regions where power supply is not regulated and the water supplier has to manage the demand with minimum possible cost. The consumption is constrained to organise rationing, and thus known day after day. Furthermore, the same...

This paper presents a water supply problem arising from the regions where power supply is not regulated and the water supplier has to manage the demand with minimum possible cost. The consumption is constrained to organise rationing, and thus known day after day. Furthermore, the same...