Federico Malucelli

Demand Adaptive Systems: Some Proposals on Flexible Transit1

Traditional public transport systems are evolving towards more flexible organizations in order to capture additional demand and reduce operational costs. Such a trend calls for new models and tools to support the management of new services that make use of public facilities to meet individual need.

Regional mass transit assignment with resource constraints

This paper considers a mass transit system in a regional area. The problem of improving the quality of the service by decreasing the total passenger waiting time is studied. A model to improve the effectiveness of the system without worsening the cost (vehicles and duties) and the passenger assignment is proposed, along with a new definition of passenger assignment to support the proposed model.

A Linear Algorithm for the Hyper-Wiener Number of Chemical Trees

An algorithm with a complexity linear in the number of vertices is proposed for the computation of the Hyper-Wiener index of chemical trees. This complexity is the best possible. Computational experience for alkanes is reported.

A polynomially solvable class of quadratic semi-assignment problems

Abstract The Quadratic Semi-Assignment Problem (QSAP) models a large variety of practical applications. In the present note we will consider a particular class of QSAP that can be solved by determining the maximum cost flow on a network. This class of problems arises in schedule synchronization and in transportation.

Testing Optimality for Quadratic 0-1 Problems

Abstract: The issue tackled is testing whether a given solution of a quadratic 0-1 problem is optimal. The paper presents an algorithm based on the necessary and sufficient optimality condition introduced by Hirriart-Urruty for general convex problems. A measure of the quality of the solution is provided. Computational results show the applicability of the method. The method is extended to constrained quadratic 0-1 problems such as quadratic assignment and quadratic knapsack .

On a 2-dimensional equipartition problem

Abstract The present paper deals with the following problem, which arises in a variety of applications: given a node-weighted rectangular grid graph, perform p horizontal full cuts and q vertical ones so as to make the weights of the resulting (p+1)(q+1) rectangular subgrids “as close as possible”. Computational complexity aspects are discussed. Several heuristic algorithms for obtaining partitions which minimize the maximum weight of a subgrid are developed, and computational results are reported. Theoretical bounds on the approximation error are also given.