Criteria for local transport subsidies

Governments have rarely been content to leave the provision of public transport services entirely to the market. Competition has been regulated and increasingly services have been subsidized from public funds. However, the criteria for such subsidies have been a continuing source of debate. Economists have tended to emphasize efficiency criteria and advocated the use of cost‐benefit analysis, but, for a variety of reasons, in the U.K. at least, this approach does not seem to have played a major role in the allocation of subsidies. Others have advocated more needs‐based approaches. Whilst these have been tried, they also have their limitations. The first few sections of the paper, therefore, review the development of these approaches in the U.K. and consider their shortcomings from the point of view of deciding on transport subsidies. In the latter part of the paper it is suggested that developments in the appraisal of health care procedures, particularly in the use of cost‐utility techniques, indicate a possible alternative approach. The approach in the health context is outlined and it is demonstrated how it might be applied to the appraisal of local transport services.     

Low-aspect ratio appendages for wind-assisted ships

Journal of Marine Science and Technology - Wind propulsion for commercial ships has been identified as a key component in the energy transition for the maritime industry. The sailing hybrid ship...     

A fractional perspective to the modelling of Lisbon’s public transportation network

Transportation - Urban growth originates multiscale spatial patterns, such as those of transportation networks. Here, the public transportation network (PTN) of the city of Lisbon is analysed from...     

A differential evolution approach for the vehicle routing problem with backhauls and time windows

This paper presents a differential evolution algorithm (DEA) to solve a vehicle routing problem with backhauls and time windows (VRPBTW) and applied for a catering firm. VRPBTW is an extension of the vehicle routing problem, which includes capacity and time window constraints. In this problem, customers are divided into two subsets: linehaul and backhaul. Each vehicle starts from a depot and goods are delivered from the depot to the linehaul customers. Goods are subsequently brought back to the depot from the backhaul customers. The objective is to minimize the total distance that satisfies all of the constraints. The problem is formulated using mixed integer programming and solved using DEA. Proposed algorithm is tested with several benchmark problems to demonstrate effectiveness and efficiency of the algorithm and results show that our proposed algorithm can find superior solutions for most of the problems in comparison with the best known solutions. Hence, DEA was carried out for catering firm to minimize total transportation costs. Copyright © 2013 John Wiley & Sons, Ltd.     

Application of a real-coded genetic algorithm for the fitting of a ship hull surface through a single non-uniform B-spline surface

In digital ship-design processes, surface modeling needs to be as accurate as possible for effectiveness in ship production as well as numerical analysis of the performance. Traditionally, the form of a ship hull is constructed from a set of cross-sectional data. This approach entails difficulties in the cross-sectional spacing and accuracy of the characteristic curves, such as the stern and bow profiles, deck side line, bottom tangential line, and unconnected curves. Genetic algorithms (GAs) have attracted increasing attention as a multimodal optimization solution for surface reconstruction that enable construction of a single non-uniform B-spline (NUB) surface at the initial stage of ship design with constraints such as knuckles, discontinuity conditions, and bulbous bows with high curvatures, . The first, simultaneous multi-fitting GA determines the boundary curves, such as the stem and stern profiles, and finds the common knot values for both curves. Similarly, the same GA technique is applied for other boundary curves at the bottom and the deck. The second GA is employed to fit the interior data points after the boundary curves are fitted. The encoded design variables for surface construction are the locations of the vertices and the knot values. Those variables are modified for improving the surface quality until a predefined degree of precision is attained. In four instances of application, the GA technique developed in this research has been shown to provide good, single, NUB surfaces with high efficiency. In the early design stage, a single NUB surface is more convenient for performance visualization and finite-element methods. It can be readily translated into many CAD/CAM packages, which facilitate the smooth transition of data across the different design stages.     

Some managerial and technical issues in transport sector development projects

In development projects there is only one problem, but it is huge: everything is connected to everything else. The authors separated from the whole the following important issues: (1) Project management and coordination: The Recipient Country’s Aid Coordination Unit (ACU) and Project Implementation Unit (PIU) staffed with competent local experts are necessary to hold the reform process memory. This issue is considered in the context of “Ownership” and “Government Leadership” as it is recognized in donor aid forums in the last decade. (2) Human resource development: Most technical assistance is oriented toward providing solutions, and the development of local capacities is ignored. The authors point out the importance of specially selected local experts—the “Technical Communication Officers”. (3) Institutional functioning: A ‘process consultation’ approach to institutional restructuring is promoted in which the Recipient has the key role. It is also recommended that the Recipient is the initiator of technical assistance in the projects. (4) Design standards are a recurrent and difficult problem. Recommendations are necessary how to transit to the new standards and how to mediate their approval process. (5) Procurement and management of consulting services: The authors argue that the recipient country qualified professionals have to be in the lead role. The vignettes in the paper are from the “real world” although they are modified slightly to protect privacy.     

Modeling and analysis of a fuel-injection pump used in diesel engines

The Fuel-Injection Pump (FIP) used in diesel engine has a higher-pair cam-mechanism to pressurize the fuel for injection. This paper proposes a methodology to model FIP from a multibody Dynamics (MBD) perspective. The results from the model include the temporal behavior of driving torque, contact Hertz stress and reaction forces at various joints. The model helps the designer to assess the effect of various cam profiles, link parameters and other design variables. It is necessary that these parameters be optimized for future high pressure applications. For this purpose, a cam-mechanism with offset follower axis is analysed. Decoupled Natural Orthogonal Complement (DeNOC) matrices based algorithm is used to model FIP without and with offset cam-mechanism. The study shows that, the offset cam-mechanism allows reduction in the side-thrust, reaction forces, and the contact Hertz stress acting on the cam-follower interface. As a typical case, for an FIP working around a pressure value of 600 bar, an optimum offset value is found to be 9.5 mm and it shows a reduction of about 45% in side thrust values. To validate the modeling approach, experimental studies are performed on pump without and with offset cam-mechanism. Experimental results are in qualitative agreement with the theoretical model results.     

Model Predictive Coordinated Control for Dual-Mode Power-Split Hybrid Electric Vehicle

Power-split hybrid electric vehicles (HEVs) have great potential fuel efficiency and have attracted extensive research attention with regard to their control system. The coordinated controller in HEV plays an important role in tracking the optimal state reference generated by the energy management strategy (EMS), so as to reach the desired fuel efficiency. Meanwhile, the coordinated controller also has a significant impact on driving performance. To improve its performance, the design of a model predictive control (MPC) based coordinated controller in power-split HEV is presented. First, a non-linear, time-varying constrained control oriented transmission model of a dual-mode power-split HEV is formulated to describe this control problem. Then, to solve this problem, the non-linear part in the transmission model is linearised, and a linear MPC is used to obtain the control signals for the motors and engine at each time step. To meet the requirements of real-time computation, a fast MPC method is also applied to reduce the online computation effort. Simulations and experiments demonstrate the effectiveness of the proposed MPC-based coordinated controller.     

Optimal Design for the Rear-Glass Joint of an Automobile for Squeak and Rattle Noise Reduction

Ever since vehicle noise, vibration, and harshness (NVH) reduction technology made dramatic improvements, vehicle interior noises represented by Squeak and Rattle (S/R) becomes an ever more important factor to improve the emotional quality of vehicles. Generally, people detect S/R noises on automotive interior parts, brake system, suspension, Body in White (BIW), etc. Among them, the rear-glass joint is a major source for vehicle interior noise, and can cause S/R noises under a variety of environmental and driving conditions. This study uses, two approaches, experimental and numerical approaches, to define the cause of S/R noise at the rear-glass section. Based on these two approaches, this study confirms that S/R noises generate through the contact between bottom side of molding and BIW. The sealant penetration length, panelmolding distance, and sealant width are the parameters affecting noise generation. In addition, this study created an optimal design with Design of Experiments (DOE) of the rear-glass joint. The design maximized the sealant penetration length, which is a parameter that majorly affects noise. The optimal design comprises of two steps: sealant injections shape optimization and rear-glass joint parameter optimization. Each step is carried out with FEA and validated by sealant penetration experiments. Through these optimizations, this study obtained an optimum combination of design parameters and fignificantly reduced the noise generated by rear-glass section.     

The development of road and rail transport safety valuation in the United Kingdom

An extensive body of theoretical and empirical work has been undertaken in the UK since the middle of the last century on the estimation of values of safety for use in the appraisal of proposed transport projects, particularly road and rail. This research has focused largely on ‘willingness-to-pay’ based values in order to measure the strength of the travelling public's preference for marginal improvements in transport safety, relative to consumption of other goods and services. In terms of practical policy making, the research has resulted in a set of values for the prevention of statistical fatalities and non-fatal injuries that are applied not only in transport safety decision making, but also in other public sector contexts. This paper summarises the main findings of this research.