Analyse qualitative des pratiques pédagogiques des enseignants de la conduite et de l’effet de l’expérience du métier

The first stage of the EPEC research (2007–2010) presented in this article enables to know better driving teachers’ pedagogical practises. We have thus observed 26 subjects, 13 experienced driving teachers and 13 novice driving teachers in real training situations, during their theoretical and practical lessons. The analysis of their practises enables to suggest pedagogical changes. The results concern mainly the theoretical and practical lessons as well as the choice of complex situations. These results enable us to prepare the second stage of this research: the construction of remediation exercises with driving teachers intended for learners in difficulty.     

Experimental Study of System Optimization for Suppression of Vehicle Vibration

The improvements of ride comfort and vehicle maneuverability in the vehicle design can be achieved by using an active suspension. However, the problems in such a control are the complex control logic because of the control laws incompatible with the improvements of ride comfort and maneuverability, and the cost increase because of various sensors to be attached. Therefore, we examined the control abilities of ride comfort and maneuverability on a unique control law using frequency shaped LQ, and controlled the characteristic of the contact between tire and road without a road displacement sensor     

How much do people value the environment?

The selection and evaluation of road schemes through the Leitch framework is based on a combination of cost-benefit analysis and environmental impact assessment. Both techniques involve the definition and valuation of a number of costs and benefits. These costs and benefits are defined and valued in isolation to each other so that we know virtually nothing about the relative valuation that people assign to different types of costs and benefits which might affect them directly or indirectly. This paper outlines the development of a method which allows people to conceptualise the costs and benefits of a road scheme in their own terms and then to rank schemes in relation to those costs and benefits. This method is based upon an interview process involving the use of repertory grid technique. The information from the repertory grid technique is used as a sound basis for determining trade-offs between attributes and for attempting to obtain monetary valuations of different project attributes. A number of exploratory interviews are reported which outline some of the difficulties with a number of the survey features including the choice of case-study, interviewer and information biases and sample and non-response biases. Various ways of dealing with these difficulties are discussed.     

Sensitivity of train stochastic dynamics to long-term evolution of track irregularities

The influence of the track geometry on the dynamic response of the train is of great concern for the railway companies, because they have to guarantee the safety of the train passengers in ensuring the stability of the train. In this paper, the long-term evolution of the dynamic response of the train on a stretch of the railway track is studied with respect to the long-term evolution of the track geometry. The characterisation of the long-term evolution of the train response allows the railway companies to start off maintenance operations of the track at the best moment. The study is performed using measurements of the track geometry, which are carried out very regularly by a measuring train. A stochastic model of the studied stretch of track is created in order to take into account the measurement uncertainties in the track geometry. The dynamic response of the train is simulated with a multibody software. A noise is added in output of the simulation to consider the uncertainties in the computational model of the train dynamics. Indicators on the dynamic response of the train are defined, allowing to visualize the long-term evolution of the stability and the comfort of the train, when the track geometry deteriorates.     

Cost-based approach for sizing of pedestrian facilities

Pedestrian facility size is currently determined in direct relationship to the design level of service. However, the design level of service is chosen arbitrarily from the six levels of service, which are assumed to represent the freedom available for movement at different levels of pedestrian flow. This direct and simple approach to facility sizing is shown to have two fundamental deficiencies that contribute to wasteful over capacity. In this article, a cost-based approach is introduced to overcome the deficiencies. Two analytical models, one for determining optimal design density and another for determining optimal design flow, are presented. The optimum design parameters minimize the total cost of the facility defined as the sum of construction cost and user cost. The sensitivity of the optimum parameters to the cost and pedestrian flow parameters is demonstrated using a numerical example.     

Introduction to an innovative crew composition approach based on safety/operational and financial requirements

This paper proposes a tool to estimate crew composition based on safety/operational and financial requirements. As there is a tendency of ship owners to implement improved technologies on board their vessels, there is no systematic way to predict their potential effect on crew size and composition (typically determined by flag state authorities on a case-to-case basis) nor on the type and complexity of on board duties new technologies might dictate. The main aim of this paper is to develop a tool to assist in determining crew composition, by taking into account both administration’s and the ship owner’s point of view. Based on data collected from ship owners, a data mining technique is implemented in order to form a generalized framework that estimates crew composition as a function of ship type, size, and degree of automation. The agreement of model predictions with records from specific (vessel) cases is very good in terms of safety (for operations such as watchkeeping, mooring/unmooring, loading/unloading). The specific intended use of this tool is to help a ship owner decide whether it is cost-beneficial to retrofit a conventional vessel with advanced technologies that would potentially entail a reduced crew (probably dealing with different and more complex on board duties). Its main benefits are that it can be used to estimate crew composition before any vessel construction or upgrade has actually taken place and that it allows crew composition to be easily adapted to the technological evolution of ship systems even at their current rapid pace.     

Mandatory independent action: a legislative paradox

The US penchant for competition in ocean liner shipping, coupled with the might of lobbyists in Washington, D.C.,led to the introduction of intraconference competition in the form of mandatory independent action. The author analysis this controversial provision and its ramifications, and suggests pragmatic modifications to quell the war of attrition between shippers and carriers.     

An Investigation of High-Speed Automobile Steering Response

The significance of the effects of steering compliance and aerodynamic life on high speed automobile's steering response was investigated on two vehicles, a Ford Falcon XW (1969) station-wagon and a GM-Holden Kingswood HQ (1974) sedan. An aerofoil was mounted above the front bumper bar of the Ford Falcon to enable the simulation of vehicles with very degraded aerodynamic characteristics. Mathematical analysis showed the importance of the inclusion of steering compliance effects in determining stability factor, and hence the vehicle's high speed yaw rate sensitivity. Both experiments and theory showed that the actual high speed yaw rate response is not significantly less than that predicted from a low speed skid pad test, however, slight errors were found which are likely to be due to steering system nonlinearity and the effects of aerodynamic lift.