Wave impact on a horizontal elastic plate

The objective is to find slamming-induced local stresses in the steel or aluminum wetdeck of a multihull vessel. This is studied theoretically by representing the wetdeck as a beam model and accounting for dynamic hydroelastic effects. Two numerical methods are used, one being a simplified asymptotic solution. Satisfactory agreement between the two methods is reported. Experimental drop tests of horizontal elastic plates of steel and aluminum are also reported, and the results from the experiments agree well with the numerical computations. This study reveals, both numerically and experimentally, that slamming-induced local stresses are strongly influenced by dynamic hydroelastic effects. The maximum bending stresses are insensitive to where waves hit, the curvature of the waves, and maximum pressures. Measured maximum pressures are very sensitive to external conditions, and cannot be used as a measure of maximum local bending stresses. A simple procedure for local design stresses due to wetdeck slamming is outlined.     

The dynamics of traffic assignment and traffic control: A theoretical study

The paper considers traffic assignment, with traffic controls, in an increasingly dynamic way. First, a natural way of introducing the responsive policy, P_o, into steady state traffic assignment is presented. Then it is shown that natural stability results follow within a dynamical version of this static equilibrium model (still with a constant demand). We are able to obtain similar stability results when queues are explicitly allowed for, provided demand is constant. Finally we allow demand to vary with time; we consider the dynamic assignment problem with signal-settings now fixed. Here we assume that vehicles are very short and that deterministic queueing theory applies, and show that the time-dependent queueing delay at the bottleneck at the end of a link is a monotone function of the time-dependent input profile to the bottleneck. We have been unable to obtain results when dynamic demand and responsive signal control are combined.     

Gasket life criteria at low temperatures adopting proportional compensation for loss of flexibility and conformability

In the automobile industry, the service life of gaskets is defined as the time until which a released gasket recovers 60 % of the original compression. It was observed that the recovery curves of gaskets were highly nonlinear at high temperatures, and relatively nonlinear at temperatures above the room temperature. However, it was also noted that the recovery curves of the gaskets at temperatures below room temperature exhibited linearity with respect to the ln(time). Automotive manufacturers demand gasket life criteria that exceed a specific time or the entire life of a car. In the case of gaskets used at lower temperatures, since materials encounter losses in its flexibility and conformability, the definition of service life specifying a 60 % recovery may not be sufficiently safe to eliminate possible leakages. In this study, new gasket life criteria that could be used at low temperatures were proposed. The new criteria were proposed based on the change in Young’s modulus of the gasket material in order to conserve the sealing capability.     

Experimental study on performance of combined cambered-type wave absorbing beach

Wave simulation performance and its quality are key factors to reflect the overall capacity and level of an ocean engineering basin. They include wave simulating and absorbing capacity of reflected waves. In order to reduce the influence of reflected waves, various wave absorbing devices are equipped in ocean engineering basins across the world. The experimental investigation into the performance of combined cambered-type wave absorbing beach (CCTWAB) with damping bars equipped in Deepwater Offshore Basin is conducted. The experiment adopts the two-point method. The reflection coefficients are calculated by the method, in which the incident and reflected waves can be separated from the physically simulated composite waves with different periods and wave heights in the time domain. The experimental results indicate that in the range of normal wave heights and periods for model tests, the CCTWAB with damping bars is excellent in eliminating the reflected waves.     

Intermodal Transit System Coordination

In urban areas where transit demand is widely spread, passengers may be served by an intermodal transit system, consisting of a rail transit line (or a bus rapid transit route) and a number of feeder routes connecting at different transfer stations. In such a system, passengers may need one or more transfers to complete their journey. Therefore, scheduling vehicles operating in the system with special attention to reduce transfer time can contribute significantly to service quality improvements. Schedule synchronization may significantly reduce transfer delays at transfer stations where various routes interconnect. Since vehicle arrivals are stochastic, slack time allowances in vehicle schedules may be desirable to reduce the probability of missed connections. An objective total cost function, including supplier and user costs, is formulated for optimizing the coordination of a general intermodal transit network. A four-stage procedure is developed for determining the optimal coordination status among routes at every transfer station. Considering stochastic feeder vehicle arrivals at transfer stations, the slack times of coordinated routes are optimized, by balancing the savings from transfer delays and additional cost from slack delays and operating costs. The model thus developed is used to optimize the coordination of an intermodal transit network, while the impact of a range of factors on coordination (e.g., demand, standard deviation of vehicle arrival times, etc) is examined.     

轻轨车辆的制造

根据庞巴迪运输部德国车辆制造有限公司（ＤＷＡ）轻轨车设计开发、车体模型制作与试验等课题研究情况，进一步介绍如何实现车体轻量化结构、防撞击设计、防火安全及采用的先进的焊接技术。     

A note on using Davidson's function in equilibrium assignment

This paper describes the use of the Davidson congestion function in modelling network flows using equilibrium assignment. A modification to the function is given, which defines the function over all flows values, and consequently removes computational difficulties noted in earlier studies. The modification requires the inclusion of an additional model parameter, and the selection of a suitable value for this parameter is studied for two sets of data. The modified Davidson function is also compared to two alternative functions; a step-wise linear function and a quartic polynomial function, which have both been proposed as congestion functions. Comparisons are made between observed link volumes and the assigned volumes from these models. It is concluded that the modified Davidson function is useful for inclusion in an equilibrium assignment model, given its ability to reflect differences in network link type (e.g. capacity and speed) and environment through its parameters, the conceptual advantage of the function through its derivation from queueing theory, and the previous discovery of reliable methods for estimating its parameters. A value of about 0.8–0.9 is suggested for the parameter (μ, 0 < μ < 1) introduced in the modification.     

Systematic budget allocation for transportation construction projects: a case in Taiwan

It has always been a daunting task for any government to allocate the budgets for public infrastructure effectively so as to maximize the benefits of the limited resources. The most important contribution this paper makes is to conduct an empirical study of the budget allocations of the six region-based road system construction plans in northern Taiwan using the transportation budget allocation model devised in this paper. After reviewing the results, the experts consulted while preparing this paper believe that these results are both objective and able to meet the actual requirements. The competent authority also believes that they are better than those obtained using their original approach. In particular, the construction of this model takes into consideration the highest-level supervisors. To a certain degree, it caters for the practices in budget allocation so that the managers are able to assume the authority corresponding to their responsibility concerning management efficiency and final outcomes.     

Trip generation of vulnerable populations in three Canadian cities: a spatial ordered probit approach

This paper provides an analysis of trip generation of three vulnerable groups: single-parent families, low income households, and the elderly. It compares the mobility of these groups to that of the general population in three Canadian urban areas of Hamilton, Montreal and Toronto, based on data from large-sample metropolitan transport surveys. An ordered probit model with spatially expanded coefficients is used for the analysis. Spatial expansion shows that there are spatial mobility trends for elderly populations and low-income populations even after socio-economic attributes are accounted for. Such spatial differences are not generally found for single parent families. This novel spatial analysis provides clues as to where vulnerable populations may experience greater degrees of social exclusion. It provides information to help prioritize transportation infrastructure projects or other social programs to take into account the needs of vulnerable populations with the lowest levels of mobility.     

Parameter transfer of common-metric attributes in choice analysis: implications for willingness to pay

There is a growing literature that promotes the presence of a mix of compensatory and semi-compensatory processing strategies in the way that individuals evaluate packages of attributes in real or hypothetical markets, and make choices. This paper proposes a specification for the utility form in a choice model to test if, given a pair of attributes with a common-metric (e.g., components of travel time or cost), the attribute with the dominating level defines the marginal (dis)utility that is assigned to both attributes. We refer to this processing strategy as a parameter transfer rule. We use a stated choice data set, in the context of car driving individuals choosing between tolled and non-tolled routes, to estimate a mixed logit model which incorporates the presence of the parameter transfer rule and the conventional fully compensatory rule, both existing up to a probability. We find that if this parameter transfer heuristic is part of the mix, the WTP is more than 30% higher, on average, than when only a fully compensatory rule is imposed. We also contrast the parameter transfer rule with other semi-compensatory heuristics which have been investigated in other papers, and show that the finding adds further support to the accumulating evidence that a semi-compensatory attribute processing rules tend to result in higher mean WTP estimates compared to the fully compensatory attribute processing rule.