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Boucheneb H.,Station Center ville | Barkaoui K.,French National Conservatory of Arts and Crafts
Information Sciences

Due to the critical role of workflows in organizations, their design must be assisted by automatic formal verification approaches. The aim is to prove formally, before implementation, their correctness w.r.t. the required properties such as achieving safely the expected services (soundness property). In this perspective, time workflow nets (TWF-nets for short) are proposed as a framework to specify and verify the soundness of workflows. The verification process is based on state space abstractions and takes into account the time constraints of workflows. However, it suffers from the state explosion problem due the interleaving semantics of TWF-nets. To attenuate this problem, this paper investigates the combination of a state space abstraction with a partial order reduction technique. Firstly, it shows that to verify soundness of a TWF-net, it suffices to explore its non-equivalent firing sequences. Then, it establishes a selection procedure of the subset of transitions to explore from each abstract state and proves that it covers all its non-equivalent firing sequences. Finally, the effectiveness of the proposed approach is assessed by some experimental results. © 2014 Elsevier Inc. All rights reserved. Source

Paez A.,McMaster University | Moniruzzaman M.,McMaster University | Bourbonnais P.-L.,Station Center ville | Morency C.,Station Center ville
Transportation Research Part A: Policy and Practice

A mixture of modes is considered a key element towards sustainable transportation. New technologies that provide information about various modes and environments can help to inform choices regarding travel and accessibility. In this paper we describe the development of a web-based accessibility calculator prototype for the Greater Montreal Area in Canada. The core of this tool is a statistical model of trip length developed using the spatial expansion method. The model is used to obtain estimates of trip length for a desired profile, based on attributes such as age, gender, family structure, and mode of travel, as well as geographical location. These estimates are used to calculate a cumulative opportunities accessibility measure to different types of essential destinations. Travel behavior information is drawn from Montreal's 2008 Household Travel Surveys. Geocoded information about trip origins and destinations is used to calculate trip length. A broad array of covariates related to individual and household attributes, and urban form are used. A geocoded business point database is used for the calculation of cumulative opportunities. To simplify the use of the accessibility calculator, the model is implemented in a user-friendly way using Google Maps API v3 and a convenient interface. Different possible uses of the accessibility calculator are illustrated in the paper. The accessibility calculator can be used by members of the public or planners/policy makers to measure the level of accessibility for a specific address and personal profile by various modes of transportation. © 2013 The Authors. Source

Paez A.,McMaster University | Trepanier M.,Station Center ville | Trepanier M.,University of Montreal | Morency C.,Station Center ville | Morency C.,University of Montreal
Transportation Research Part A: Policy and Practice

Smart card automated fare payment systems are being adopted by transit agencies around the world. The data-storage characteristics of smart cards present novel opportunities to enhance transit services. On the one hand, there are fare policies, where smart card holders are given specific rebates on the use of the service based on usage patterns or levels. On the other, there are non-fare policies, for instance if holders receive advantages, such as rebates and offers, from commercial partners. The purpose of this paper is to present a geodemographic framework to identify potential commercial partnerships that could exploit the characteristics of smart cards. The framework is demonstrated using data from Montreal, Canada. Household survey data, specifically trip ends, and business data points are jointly used to determine the exposure of various types of establishments to users of the Montreal Metro network. Spatial analysis of business establishments in the neighborhood of metro stations helps to identify potential commercial partners. The results illustrate the potential of geodemographic analysis to generate intelligence of commercial interest. © 2011 Elsevier Ltd. Source

Autixier L.,E Source | Autixier L.,Station Center ville | Mailhot A.,Center Eau Terre Environnement | Bolduc S.,Center Eau Terre Environnement | And 5 more authors.
Science of the Total Environment

The implications of climate change and changing precipitation patterns need to be investigated to evaluate mitigation measures for source water protection. Potential solutions need first to be evaluated under present climate conditions to determine their utility as climate change adaptation strategies. An urban drainage network receiving both stormwater and wastewater was studied to evaluate potential solutions to reduce the impact of combined sewer overflows (CSOs) in a drinking water source. A detailed hydraulic model was applied to the drainage basin to model the implementation of best management practices at a drainage basin scale. The model was calibrated and validated with field data of CSO flows for seven events from a survey conducted in 2009 and 2010. Rain gardens were evaluated for their reduction of volumes of water entering the drainage network and of CSOs. Scenarios with different levels of implementation were considered and evaluated. Of the total impervious area within the basin directly connected to the sewer system, a maximum of 21% could be alternately directed towards rain gardens. The runoff reductions for the entire catchment ranged from 12.7% to 19.4% depending on the event considered. The maximum discharged volume reduction ranged from 13% to 62% and the maximum peak flow rate reduction ranged from 7% to 56%. Of concern is that in-sewer sediment resuspension is an important process to consider with regard to the efficacy of best management practices aimed at reducing extreme loads and concentrations. Rain gardens were less effective for large events, which are of greater importance for drinking water sources. These practices could increase peak instantaneous loads as a result of greater in-sewer resuspension during large events. Multiple interventions would be required to achieve the objectives of reducing the number, total volumes and peak contaminant loads of overflows upstream of drinking water intakes. © 2014 Elsevier B.V. Source

Woch A.,Station Center ville | Plamondon R.,Station Center ville | O'Reilly C.,Station Center ville
Human Movement Science

In this paper, 14 healthy subjects in two age groups have produced rapid handwriting strokes with a direction reversal. The delta-lognormal model was used to obtain a detailed description of the velocity of these movements and of the neuromuscular synergy that produces them. This modeling also allowed the derivation of new hypothesis on the nature of the slowing effect due to aging (i.e., a direct effect or a coping strategy) and on its repartition on the different steps of the movement production (i.e., its preparation versus its execution). Our analysis revealed a substantial increase of neuromuscular response delays and a decrease of the command amplitudes with age. For the parameters that show a significant decrease in performance, the agonist and antagonist systems were affected similarly. In addition, we observed that the age has a proportional effect on the various time characteristics of the movements and that even in the case of a significant slowing down of the neuromuscular systems, the elderly can still achieve optimal movement responses, characterized by the use of a single delta-lognormal primitive. This performance might be related to the preservation of some movement timing properties and relationships between the agonist and the antagonist neuromuscular systems. © 2010 Elsevier B.V. Source

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