Airport, airline and access mode choice in the San Francisco Bay area

In this article, we present an analysis of air travel choice behaviour in the San Francisco Bay area. The analysis extends existing work by considering the simultaneous choice by passengers of a departure airport, an airline, and an access mode. The analysis shows that several factors, most notably flight frequency and in-vehicle access time, have a significant overall impact on the attractiveness of an airport, airline and access mode combination, while factors such as fare and aircraft size have a significant effect only in some of the population subgroups. The analysis highlights the need to use separate models for resident and non-resident travellers, and to segment the population by journey purpose. The analysis also shows that important gains can be made through the inclusion of airport-inertia variables, and through using a nonlinear specification for the marginal returns of increases in flight frequency. In terms of model structure, the results suggest that the use of the different possible two-level nested logit models leads to modest, yet significant gains in model fit over the corresponding multinomial logit models, which already exhibit very high levels of prediction performance

Model study on “pendulor” type wave energy device to Utilize ocean wave energy in Sri Lanka

Sri Lanka being an island it is inevitable to utilize the ocean wave energy as a sustainable energy source. The device called “Pendulor”, which is invented in Japan and has proven 40-50% of wave energy conversion efficiency at the sea of Muroran, Japan. The low wave energy density oceanic climate of Sri Lanka makes this device more preferred, because of its high energy conversion capability. The device consist a pendulum flap hinged inside a caisson and the caisson is faced to the ocean waves. The economical feasibility of this device depends on the construction cost. The conventional caisson is a straight chamber and this type of a device is infeasible because of the length that causes increase in construction cost. A modified caisson is proposed to shorten the caisson length towards the sea and to increase the frequency bandwidth of operation. Model testing of this modified caisson with a solid friction damper is addressed in this endeavor. Laboratory experiments were conducted with a 1/16 scale model of the proposed caisson. A solid friction damper was used for the model testing and a mathematical model for the device was developed and the parametric modeling was done by using MATLAB. The power conversion efficiency with a modified caisson was discussed in this endeavor