Optimal Linear Active Suspensions with Integral Constraint

This paper considers the application of linear optimal control to the design of an active automobile suspension system. By inclusion of an integral constraint in the performance index it is possible to achieve zero steady state axle to body response to both static body forces and ramp road inputs. Full state feedback is achieved by reconstructing the state variables from easily measured quantities.     

Static and changing port economic impacts

This paper attempts to provide general guidelines for conducting a port' economic impact analysis. In so doing, a methodology is proposed to organize efficiency the search for port-related industries and to determine the degree of their dependence on a port. this methodology is applied to the port of Hampton Roads. In addition, some constraints in predicting the changes in the economic impact of a port attribute to changes in the volume cargo are identified.     

Coal-fixed turbines versus diesel: an Australian context

This paper considers the economics of the diesel engine as against that of coal-fired turbines for ship propulsion in the context of the world energy debate. After formulating a generalized model of propulsive plant choice the model is applied to a particular Australian export trade.     

Locating and sizing park-ride lots with interactive computer graphs

Two alternative methods for conducting a preliminary analysis of the problem of locating and sizing park-ride lots for an urban bus transit system are examined. These alternative methods are tested using a large and complex street network representing the northern half of the City of Seattle, Washington. Four design criteria are identified and an overall measure of system performance is devised. The problem is to determine the size and location of three park-ride lots that will maximize the performance of the system. The first method utilizes a computing system called LOCATOR II in an interactive graphic mode. In an experimental setting, five students use LOCATOR II to locate three park-ride lots and their solutions are found to exhibit a very high average level of performance. The second method does not involve a direct interaction with the computing system but does use LOCATOR II in a batch mode. Several students participate in three rounds of the batch mode experiment and the performance of their designs is somewhat poorer than the designs found in the interactive graphics experiment. Overall, the experimental results show that relatively inexperienced persons can find a high performance design for a reasonably complex problem quickly and inexpensively. These designs can provide a good starting point for the detailed consideration of many of the other aspects of the problem of providing a high performance bus transit service in an urban area.     

Ride Dynamics of Articulated Vehicles-A Literature Survey

This paper presents a review of the available literature describing the methods of modelling the vibrational response of articulated vehicles to the road inputs at the tire contact points. It states and discusses the mathematical techniques that have been put forward for obtaining road input characteristics, for modelling the vehicles in a range of degrees of freedom, and for performing the analysis necessary to obtain the vibrational response. Finally the indices that have been proposed for ride comfort and ride safety are given and the manner in which various researchers relate these to the vibrational characteristics of the vehicles is described.     

Analytical Tire Models for Dynamic Vehicle Simulation

Four basic tire models suitable for dynamic vehicle simulation are formulated. The models are compared through a six-degree-of-freedom nonlinear simulation of a cargo truck crossing rough ground. Guidelines are developed for the selection of an optimum tire model for a given dynamic vehicle simulation.     

Some Thoughts on Flags of Convenience

The purpose of this article is to formulate the problem, to assess its magnitude, and at the same time to suggest the areas that must be investigated before any practical policy recommendations can be made.