Service quality,satisfaction and behavioral intentions towards public transport from the point of view of private vehicle users

Transportation - In order to attract car users towards the public transport services in an urban and metropolitan context, contributing to a sustainable mobility in cities, it is fundamental to...     

A predictive dynamic traffic assignment model in congested capacity-constrained road networks

In this paper, a predictive dynamic traffic assignment model in congested capacity-constrained road networks is formulated. A traffic simulator is developed to incrementally load the traffic demand onto the network, and updates the traffic conditions dynamically. A time-dependent shortest path algorithm is also given to determine the paths with minimum actual travel time from an origin to all the destinations. The traffic simulator and time-dependent shortest path algorithm are employed in a method of successive averages to solve the dynamic equilibrium solution of the problem. A numerical example is given to illustrate the effectiveness of the proposed method.     

Recent sedimentary study of the shelf of the Basque country

The Northern Iberian margin of the Spanish Basque country (provinces of Gipuzkoa and Viscaia) is characterized by a narrow continental platform, which receives inputs of riverine particulate matter from the numerous riverine systems located within the Basque country. This particulate matter is subsequently deposited within the Bay of Biscay, and Gouf de Capbreton [Frouin, R., Fiuza, A.F.G., Ambar, I., Boyd, T.J., 1990. Observations of a poleward surface current off the coasts of Portugal and Spain during winter. Journal of Geophysical Research 95 (C1), 679–691]. The main goal of this study is to establish a map of the surface sediment distribution of the Basque continental shelf and more specifically to map the muddy patch located at the eastern side of that continental shelf.Three oceanographic cruises were conducted in 2003 and 2004. From these campaigns 340 surface samples, 12 short cores and 3 gravity cores have been collected over the mid and outer shelf from depths ranging between 50 m and 150 m deep. 3 seismic profiles were obtained across the shelf mud patch using a Sparker device.Sediment grain-size analyses were performed by the classical physical method of sieving and use of settling columns. The POC (Particular Organic Carbon) amounts in sediment and water samples were determined using the Strickland and Parsons' method [Strickland, J.D.H., Parsons, T.R., 1972. Determination of particulate carbon. In : A practical handbook of seawater analysis. Fisheries ResearchBoard of Canada, Ottawa, pp. 207−211] as adapted by Etcheber [Etcheber, H., 1981. Comparaison des diverses méthodes d'évaluation des teneurs en matières en suspension et en carbone organique particulaire des eaux marines du plateau continental aquitain. Journal de Recherche Océanographique VI (2), 37−42]. Radioisotopic measurements (²¹⁰Pb_exc) were made using a semi-planar germanium detector coupled to a multichannel analyser. Radiographical analysis was performed with an X-ray equipment (SCOPIX®) coupled with a radioscopy instrumentation and processing unit.Firstly, a detailed sedimentological map of this shelf has been produced and secondly, geophysical surveys have precisely mapped the geometry of the main mud patch on the continental shelf. In the mud patch itself the rates of sedimentation are between 0.13 and 0.50 cm yr^− 1. The maximum rate of sedimentation is located in the central mud patch, whereas the minimum rate of deposition occurs close to the rocky outcrops. These results seem to be in agreement with the estimation of the total thickness of the mud patch revealed by seismic profiles. The central part corresponds to the maximum thickness of 7 m.Interpretations of the associated oceanic current forcing factors (current direction, wave fetch and wind directional modes) relating to the identified sediment depositional zones are also undertaken.     

Understanding bikeability: a methodology to assess urban networks

Transportation - A fully separated bicycle network from vehicular traffic is not realistic even for the most bicycle-friendly cities. Thus, all around the world urban cycling entails switching...     

Vehicle distance estimation using a mono-camera for FCW/AEB systems

For robust vision-based forward collision warning (FCW) and autonomous emergency braking (AEB) systems, not only reliable detection performance including high detection rate and low false positives but also accurate measurement output of a target vehicle is required. Especially, in order to reduce false alarm or activation of FCW/AEB systems, the systems require the precise measurement output of a target object, such as position, velocity, acceleration, and time-to-collision (TTC). In this study, we developed a measurement estimation algorithm of a target vehicle using a monocular camera. This method estimates two cases of vehicle widths for a target vehicle by using the detected lane information and a pin-hole camera model. After that, the position, velocity, acceleration, and TTC of a target vehicle are estimated by using a Kalman filter for the each estimated vehicle width. To improve robustness, the both estimation results using the detected lane information and the pinhole camera model are fused. This estimation algorithm was evaluated and compared with the state-of-the-art technology. As a result, the proposed measurement output estimation method can improve the performance of the FCW/AEB systems.     

Comparing Fisher Interviews,Logbooks, and Catch Landings Estimates of Extraction Rates in a Small-Scale Fishery

Researchers are turning to alternative data sources (e.g., resource user knowledge) to provide information required for wildlife management. Little is known about the reliability of data elicited from resource users relative to data obtained from user-independent approaches (e.g., observations of fish catches). We test for consensus among three methods that quantify past (1996 to 2007) seahorse catch-per-unit-effort (CPUE) for a small-scale, data-poor fishery in the Philippines: interviews with fishers about good, bad, and typical catch; fisher logbooks; and observations of catch landings. Interviews and logbooks indicated no trends in CPUE through time, consistent with results from the fisher-independent metric, catch landings. Although interview estimates of “typical” CPUE greatly exceeded “typical” observed catches and logbook estimates, interview estimates of “bad” CPUE were comparable. Catch landings estimates for a fisher in a particular year were uncorrelated to what he reported during retrospective interviews. Interviews should be used cautiously to inform specific catch targets (e.g., total allowable catches), although including interview questions about a range of catch experiences (e.g., good, bad and typical), may improve interview-derived data. Logbooks are particularly useful for capturing information about fishing expeditions that produce no fish, which are largely missed by other methods.     

Actively translating a rear diffuser device for the aerodynamic drag reduction of a passenger car

This research aims to develop an actively translating rear diffuser device to reduce the aerodynamic drag experienced by passenger cars. One of the features of the device is that it is ordinarily hidden under the rear bumper but slips out backward only under high-speed driving conditions. In this study, a movable arc-shaped semi-diffuser device, round in form, is designed to maintain the streamlined automobile??s rear underbody configuration. The device is installed in the rear bumper section of a passenger car. Seven types of rear diffuser devices whose positions and protrusive lengths and widths are different (with the basic shape being identical) were installed, and Computational Fluid Dynamics (CFD) analyses were performed under moving ground and rotating wheel conditions. The main purpose of this study is to explain the aerodynamic drag reduction mechanism of a passenger car cruising at high speed via an actively translating rear diffuser device. The base pressure of the passenger car is increased by deploying the rear diffuser device, which then prevents the low-pressure air coming through the underbody from directly soaring up to the rear surface of the trunk. At the same time, the device generates a diffusing process that lowers the velocity but raises the pressure of the underbody flow, bringing about aerodynamic drag reduction. Finally, the automobile??s aerodynamic drag is reduced by an average of more than 4%, which helps to improve the constant speed fuel efficiency by approximately 2% at a range of driving speeds exceeding 70 km/h.     

Robust design optimization of suspension system by using target cascading method

This study presents the robust design optimization process of suspension system for improving vehicle dynamic performance (ride comfort, handling stability). The proposed design method is so called target cascading method where the design target of the system is cascaded from a vehicle level to a suspension system level. To formalize the proposed method in the view of design process, the design problem structure of suspension system is defined as a (hierarchical) multilevel design optimization, and the design problem for each level is solved using the robust design optimization technique based on a meta-model. Then, In order to verify the proposed design concept, it designed suspension system. For the vehicle level, 44 random variables with 3% of coefficient of variance (COV) were selected and the proposed design process solved the problem by using only 88 exact analyses that included 49 analyses for the initial meta-model and 39 analyses for SAO. For the suspension level, 54 random variables with 10% of COV were selected and the optimal designs solved the problem by using only 168 exact analyses for the front suspension system. Furthermore, 73 random variables with 10% of COV were selected and optimal designs solved the problem by using only 252 exact analyses for the rear suspension system. In order to compare the vehicle dynamic performance between the optimal design model and the initial design model, the ride comfort and the handling stability was analyzed and found to be improved by 16% and by 37%, respectively. This result proves that the suggested design method of suspension system is effective and systematic.     

Development of a Human Use Objectives Framework for Integrated Management of the Eastern Scotian Shelf

Under the 1997 Oceans Act, Fisheries and Oceans Canada (DFO) is required to lead and facilitate the development of integrated management plans for Canada's oceans. One of the integrated management projects is the Eastern Scotian Shelf Integrated Management Initiative (ESSIM), through which DFO is working with a range of stakeholders to develop and implement an integrated ocean management plan for the eastern Scotian Shelf. As part of this Initiative, DFO has undertaken a program to develop a set of objectives and related indicators for ocean management. This includes the development of a framework, objectives, and indicators for human use of the resource including the social, economic, and institutional (governance) components of ocean management, areas that have received little attention internationally. This article provides some background to ESSIM and human uses of the resources of the eastern Scotian Shelf; briefly reviews objectives-based management and human use objectives internationally; outlines the process undertaken to develop the Human Use Objectives Framework; presents the resultant objectives and indicators that were developed; and highlights some of the lessons learned and challenges for their implementation.