Search results for "systems"
showing 10 items of 11952 documents
Corporate Governance Theories: From Micro Theories to National Systems Theories
2004
The objective of this article is to conduct a survey of the different corporate governance theories. In the first part, we present the micro theories by opposing the disciplinary view to the knowledge-based view. The second part deals with the macro or national systems theories. We separate the theories based on appropriation of the organizational rent from those attributing a dominant role to production. This survey highlights that the financial view of corporate governance is a very particular case and presents many limits.
Drone arc routing problems
2018
[EN] In this article, we present some drone arc routing problems (Drone ARPs) and study their relation with well-known postman ARPs. Applications for Drone ARPs include traffic monitoring by flying over roadways, infrastructure inspection such as by flying along power transmission lines, pipelines or fences, and surveillance along linear features such as coastlines or territorial borders. Unlike the postmen in traditional ARPs, drones can travel directly between any two points in the plane without following the edges of the network. As a consequence, a drone route may service only part of an edge, with multiple routes being used to cover the entire edge. Thus the Drone ARPs are continuous o…
Some personal views on the current state and the future of locational analysis
1998
In this paper a group of participants of the 12th European Summer Institute which took place in Tenerife, Spain in June 1995 present their views on the state of the art and the future trends in Locational Analysis. The issues discussed include modeling aspects in discrete Location Theory, the influence of the distance function, the relation between discrete, network and continuous location, heuristic techniques, the state of technology and undesirable facility location. Some general questions are stated regarding the applicability of location models, promising research directions and the way technology affects the development of solution techniques.
A more efficient cutting planes approach for the green vehicle routing problem with capacitated alternative fuel stations
2021
AbstractThe Green Vehicle Routing Problem with Capacitated Alternative Fuel Stations assumes that, at each station, the number of vehicles simultaneously refueling cannot exceed the number of available pumps. The state-of-the-art solution method, based on the generation of all feasible non-dominated paths, performs well only with up to 2 pumps. In fact, it needs cloning the paths between every pair of pumps. To overcome this issue, in this paper, we propose new path-based MILP models without cloning paths, for both the scenario with private stations (i.e., owned by the fleet manager) and that with public stations. Then, a more efficient cutting plane approach is designed for addressing both…
Adaptive Large Neighborhood Search with a Constant-Time Feasibility Test for the Dial-a-Ride Problem
2019
In the dial-a-ride problem, user-specified transport requests from origin to destination points have to be served by a fleet of homogeneous vehicles. The problem variant we consider aims at finding a set of minimum-cost routes satisfying constraints on vehicle capacity, time windows, maximum route duration, and maximum user ride times. We propose an adaptive large neighborhood search (ALNS) for its solution. The key novelty of the approach is an exact amortized constant-time algorithm for evaluating the feasibility of request insertions in the repair steps of the ALNS. In addition, we use two optional improvement techniques: a local-search-based intraroute improvement of routes of promisin…
Exact solution of the soft-clustered vehicle-routing problem
2020
Abstract The soft-clustered vehicle-routing problem (SoftCluVRP) extends the classical capacitated vehicle-routing problem by one additional constraint: The customers are partitioned into clusters and feasible routes must respect the soft-cluster constraint, that is, all customers of the same cluster must be served by the same vehicle. In this article, we design and analyze different branch-and-price algorithms for the exact solution of the SoftCluVRP. The algorithms differ in the way the column-generation subproblem, a variant of the shortest-path problem with resource constraints (SPPRC), is solved. The standard approach for SPPRCs is based on dynamic-programming labeling algorithms. We s…
Branch-price-and-cut algorithms for the pickup and delivery problem with time windows and multiple stacks
2016
Abstract This paper proposes models and algorithms for the pickup and delivery vehicle routing problem with time windows and multiple stacks. Each stack is rear-loaded and is operated in a last-in-first-out (LIFO) fashion, meaning that when an item is picked up, it is positioned at the rear of a stack. An item can only be delivered if it is in that position. This problem arises in the transportation of heavy or dangerous material where unnecessary handling should be avoided, such as in the transportation of cars between car dealers and the transportation of livestock from farms to slaughterhouses. To solve this problem, we propose two different branch-price-and-cut algorithms. The first sol…
Solving a large cutting problem in the glass manufacturing industry
2020
Abstract The glass cutting problem proposed by Saint Gobain for the 2018 ROADEF challenge includes some specific constraints that prevent the direct application of procedures developed for the standard cutting problem. On the one hand, the sheets to be cut have defects that make them unique and they must be used in a given order. On the other hand, pieces are grouped in stacks and the pieces in each stack must be cut in order. There are also some additional characteristics due to the technology being used, especially the requirement for a three-stage guillotine cutting process. Taking into account the sequencing constraints on sheets and pieces, we have developed a beam search algorithm, us…
Nested branch-and-price-and-cut for vehicle routing problems with multiple resource interdependencies
2019
Abstract This paper considers vehicle routing problems (VRPs) with multiple resource interdependencies and addresses the development and computational evaluation of an exact branch-and-price-and-cut algorithm for their solution. An interdependency between two resources means that the two resource consumptions influence one another in such a way that a tradeoff exists between them. This impacts the feasibility and/or the cost of a solution. The subproblem in branch-and-price-and-cut procedures for VRPs is very often a variant of the shortest-path problem with resource constraints (SPPRC). For the exact solution of many SPPRC variants, dynamic-programming based labeling algorithms are predomi…
Stabilized branch-price-and-cut for the commodity-constrained split delivery vehicle routing problem
2019
Abstract In the commodity-constrained split delivery vehicle routing problem (C-SDVRP), customer demands are composed of sets of different commodities. The C-SDVRP asks for a minimum-distance set of routes such that all customer demands are met and vehicle capacities are respected. Moreover, whenever a commodity is delivered by a vehicle to a customer, the entire amount requested by this customer must be provided. Different commodities demanded by one customer, however, can be delivered by different vehicles. Thus, the C-SDVRP is a relaxation of the capacitated vehicle routing problem and a restriction of the split delivery vehicle routing problem. For its exact solution, we propose a branc…