The statement of the standard vehicle routing problem cannot always capture all aspects real-world applications. As a result, extensions or modifications to model are warranted. Here we consider case when customers can call in orders during daily operations; i.e., both customer locations and demands may be unknown advance. This is modeled as combined dynamic stochastic programming problem, heuristic solution method developed where sample scenarios generated, solved heuristically, iteratively...

Abstract Increased fuel costs together with environmental concerns have led shipping companies to consider the optimization of vessel speeds. Given a fixed sequence port calls, each time window, and cost as convex function speed, we show that optimal speeds can be found in quadratic time. © 2013 Wiley Periodicals, Inc. NETWORKS,

We consider a single product maritime inventory routing problem in which the production and consumption rates are constant over planning horizon. The involves heterogeneous fleet multiple ports with limited storage capacity. Maritime transportation is characterized by high levels of uncertainty, sailing times can be severely influenced varying unpredictable weather conditions. To deal this paper investigates use adaptable robust optimization where assumed to belong well-known budget polytope...

This paper studies the problem of finding optimal routes and schedules for a fleet vessels that are to perform maintenance tasks at an offshore wind farm. To solve two alternative models presented: arc-flow path-flow formulation. Both tested on instances varying numbers tasks. The model is solved with commercial software using branch-and-bound. heuristically by generating subset possible schedules, but produces close solutions lot less computing time than exact model.

Performing maintenance operations at offshore wind farms involves one major challenge compared with the onshore counterpart: All personnel and spare parts need to be transported from an port or station individual turbines by vessels helicopters. The helicopters required for these tasks will constitute a part of costs farms, reduce cost energy it is essential keep optimal near-optimal vessel fleet this purpose. We study optimization problem that arises propose appropriate model. Computational...

This paper considers a multi-product maritime inventory routing problem in which the routes of vessels are determined while inventories ports must remain within given bounds. Since there is more than one product, each port can be consumption for product and production another product. We propose matheuristic to deal with large-size instances planning horizon 60 days. The first phase heuristic identifies subset arcs order use them as input parameters second phase. In phase, mathematical model...

Abstract This paper describes a new Branch‐and‐Regret Heuristic for class of dynamic and stochastic vehicle routing problems. work is motivated by real‐life problem faced major transporter in Norway. The heuristic uses information during the solution process. method shown to be superior previous heuristics that are uniquely based on pure approach. proposed well suited problems containing customers, demands, or both. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 49(4), 330–340

In vendor-managed inventory replenishment, the vendor decides when to make deliveries customers, how much deliver, and combine shipments using available vehicles. This gives rise inventory-routing problem in which goal is coordinate replenishment transportation minimize costs. The tackled this paper stochastic problem, where demands are specified through general discrete distributions. formulated as a discounted infinite-horizon Markov decision problem. Heuristics based on finite scenario...

This paper presents a multi-objective location-districting optimization model for sustainable collection of municipal solid waste, motivated by strategic waste management decisions in Iran. The aims to design an efficient system providing services integrating the regarding urban area districting and location centers. Three objectives are minimized, given as 1) cost establishing centers collecting 2) measure destructive environmental consequences, 3) social dissatisfaction. Constraints...