Eric Cornelis

Multistate Nonhomogeneous Semi-Markov Model of Daily Activity Type, Timing, and Duration Sequence

Understanding travelers’ daily travel activity pattern formation is an important issue for activity-based travel-demand analysis. The activity pattern formation concerns not only complex interrelations between household members and individuals’ sociodemographic characteristics but also urban form and transport system settings. To investigate the effects of these attributes and the interrelationship between conducted activities, a multistate semi-Markov model is applied. The underlying assumption of the proposed model is that the state transition probability depends on its adjoining states. The statistical tests of significance affirm that the duration of activity depends not only on its beginning time of day but also on the duration of travel or activity previously conducted. An empirical study based on the Belgian mobility survey is conducted to estimate individuals’ daily activity durations of different episodes and provides useful insight for the effects of sociodemographic characteristics, urban and transportation system settings on the activity pattern formation.

PACSIM : A new dynamic behavioural model for multimodal traffic assignment

The present paper provides a brief introduction to PACSIM, a new model for multimodal traffic assignment. This model is distinguished by the introduction of several important features: full dynamism based on an event-driven paradigm, complete modelling of the network of information provided to network users, multilevel network representation, multimodal capabilities and the use of an explicit parametrisable behavioural theory. The paper discusses the main motivations and design concepts and presents an illustrative application of PACSIM to advanced incident warning. Some perspectives are finally outlined.

Emissions de gaz à effet de serre des chaînes logistiques

Pour produire et amener sur le marché une certaine quantité de biens, différentes formes d’organisations logistiques sont possibles, qui peuvent entraîner des demandes de transport, des consommations d’énergie et des émissions de gaz à effet de serre (GES) différentes. Cette communication met en évidence l’impact des choix logistiques sur les émissions de GES en comparant les émissions de chaînes logistiques concurrentes. La collecte de données et la comparaison entre chaînes concurrentes ont été menées en Belgique, en France et au Royaume-Uni, pour quelques produits de consommation courante. La comparaison entre chaînes permet d’analyser les paramètres qui déterminent l’importance des émissions de GES, tels que la distance, le type de distribution, la densité de consommateurs ou le pays.

Best Practices in Data Fusion: Synthesis of a Workshop

This chapter describes how the formal treatment of data fusion problems in the travel survey methods community is still in its infancy. Yet it is already clear that the area both holds substantial promise in terms of benefits for the future and is characterized by a range of problems that will challenge current and future generations of researchers. The authors hope that this workshop has helped to highlight some of these issues and to stimulate the participants (and others) to address these challenges with zeal, rigor and creativity in the future.