Recently Beltran-Royo et.al presented a Semi-Lagrangean relaxation for the classical p-median location problem. The results obtained using the Semi-Lagrangean relaxation approach were quite impressive. In this paper we use a reformulation of the p-median problem in order to start from a...

In this paper, we use a reformulation of the symmetric and the asymmetric travelling salesman problem more suitable for Lagrangean relaxation and analyse the new approach on examples from TSP Lib. Furthermore the Lagrangean relaxed subproblems are travelling salesman alike which means that...

In this paper we analyse the impact of different grazing policies on number of dairy cows in different grazing categories in 2025 by model simulation in the Netherlands. It can be generally concluded that in the absence of intervention there is a strong tendency towards a decline in grazing on...

Co-firing biomass and coal in retrofitted power plants is an efficient means to reduce carbon dioxide emissions in the energy sector. Under IPCC reporting rules, the impacts of energy produced from biomass would not be reported in the energy sector, thereby effectively lowering the emission...

A process system is designed for material transformations that produce certain functional chemicals while usually consuming large amounts of energy. Materials in process systems have long been the major focus of investigation to achieve better economic performance. Rising energy prices and...

In this paper, we characterize the humanitarian objectives of emergency resource allocation and distribution in disaster response operations. We formulate the humanitarian principles as three objective functions, i.e., lifesaving utility, delay cost and fairness. An integrated multi-objective...

In this paper, the maritime industry’s commitment to green supply chain has been analyzed. The objective of this study is to show that the reuse of empty containers not only adds value to a firm, but leads to waste reduction in the supply chain. The novelties of this article include (i) empty...

The economic lot sizing problem with product returns and recovery is an important problem that appears in reverse logistics, and has recently been proved to be NP-hard. In this paper, we suggest a variable neighborhood search (VNS) metaheuristic algorithm for solving this problem. It is the...

В статье рассматривается понятие и методы исследования операций, а также разделы математического программирования, входящие в состав исследования операций....

This paper proposes planning models that will assist a flower grower with the land and flower variety allocation decisions in such a way that the revenues (or profits) are maximised over a given planning period. In particular, this paper presents models where the mix of flowers is modified...