Combined ship routing and inventory management in the salmon farming industry

We consider a maritime inventory routing problem for Norway's largest salmon farmer both producing the feed at a production factory and being responsible for fish farms located along the Norwegian coast. The company has bought two new ships to transport the feed from the factory to the fish farms and is responsible for the routing and scheduling of the ships. In addition, the company has to ensure that the feed at the production factory as well as at the fish farms is within the inventory limits. A mathematical model of the problem is presented, and this model is reformulated to improve the efficiency of the branch-and-bound algorithm and tightened with valid inequalities. To derive good solutions quickly, several practical aspects of the problem are utilized and two matheuristics developed. Computational results are reported for instances based on the real problem of the salmon farmer

Propuesta de Decisión del Consejo relativa a la firma del Convenio de La Haya sobre la legislación aplicable a ciertos derechos sobre valores depositados en un intermediario.

[Context] Many security risk assessment methods are proposed both in academia typically with a graphical notation) and industry (typically with a tabular notation). [Question] We compare methods based on those two notations with respect to their actual and perceived efficacy when both groups are equipped with a domain-specific security catalogue (as typically available in industry risk assessments).[Results] Two controlled experiments with MSc students in computer science show that tabular and graphical methods are (statistically) equivalent in quality of identified threats and security controls. In the first experiment the perceived efficacy of tabular method was slightly better than the graphical one, and in the second experiment two methods are perceived as equivalent. [Contribution] A graphical notation does not warrant by itself better (security) requirements elicitation than a tabular notation in terms of the quality of actually identified requirements

Consumer versus retailer perceptions of store positioning in the UK fashion sector

SIGLEAvailable from British Library Document Supply Centre-DSC:9350.2146(9602) / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Tramp ship routing and scheduling with voyage separation requirements

In this paper we explore tramp ship routing and scheduling. Tramp ships operate much like taxies following the available demand. Tramp operators can determine some of their demand in advance by entering into long-term contracts and then try to maximise profits from optional voyages found in the spot market. Routing and scheduling a tramp fleet to best utilise fleet capacity according to current demand is therefore an ongoing and complicated problem. Here we add further complexity to the routing and scheduling problem by incorporating voyage separation requirements that enforce a minimum time spread between some voyages. The incorporation of these separation requirements helps balance the conflicting objectives of maximising profit for the tramp operator and minimising inventory costs for the charterer, since these"br/"costs increase if similar voyages are not performed with some separation in time. We have developed a new and exact branch-and-price procedure for this problem. We use a dynamic programming algorithm to generate columns and describe a time window branching scheme used to enforce the voyage separation requirements which we relax in the master problem. Computational results show that our algorithm in general finds optimal solutions very quickly and performs much faster compared to an earlier a priori path generation method. Finally, we compare our method to an earlier adaptive large neighbourhood search heuristic and find that on similar-sized instances our approach generally uses less time to find the optimal solution than the adaptive large neighbourhood search method uses to find a heuristic solution. Document type: Boo

Systematic Agile Development in Regulated Environments

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