An efficient implementation of local search algorithms for constrained routing problems

We investigate the implementation of local search algorithms for routing problems with various side constraints such as time windows on vertices and precedence relations between vertices. The algorithms are based on the k-exchange concept. In the case of unconstrained routing problems, a single k-exchange can obviously be processed in constant time. In the presence of side constraints feasibility problems arise. Testing the feasibility of a single solution requires an amount of time that is linear in the number of vertices. We show how this effort can, on the average, still be reduced to a constant

A planning board generator. Part I: Problem instances and types

A planning board is a planning tool that uses the Gantt chart as its main representation mechanism. A planning board generator aims at facilitating the development of planning boards; using a description of the problem type for which a planning board is to be developed and the desired representations and manipulations, the generator automatically creates a prototype of the planning board. In this paper we discuss our view of a planning board generator and introduce a method to describe problem instances and types

Time Slot Management in Attended Home Delivery

Many e-tailers providing attended home delivery, especially e-grocers, offer narrow delivery time slots to ensure satisfactory customer service. The choice of delivery time slots has to balance marketing and operational considerations, which results in a complex planning problem. We study the problem of selecting the set of time slots to offer in each of the zip codes in a service region. The selection needs to facilitate cost-effective delivery routes, but also needs to ensure an acceptable level of service to the customer. We present two fully-automated approaches that are capable of producing high-quality delivery time slot offerings in a reasonable amount of time. Computational experiments reveal the value of these approaches and the impact of the environment on the underlying trade-offs.integer programming;vehicle routing;continuous approximation;e-grocery;home delivery;time slots

Local search in physical distribution management

Physical distribution management presents a variety of decision making problems at three levels of strategic, tactical and operational planning. The importance of effective and efficient distribution management is evident from its associated costs. Physical distribution management at the operational level, which is considered in this paper is responsible for an important fraction of the total distribution costs. Not surprisingly, there is a growing demand for planning systems that produce economical routes. Enormous theoretical as well as practical advances have been made, in the last decade. Some of the resulting vehicle and scheduling models will be discussed in this paper, like vehicle routing problem with time window and the pickup and delivery problem with time window

Constraint classification for mixed integer programming formulations

No abstract