Showing papers on "Intelligent transportation system published in 1987"

Expert systems for traffic signal control

Abstract: The level of service achieved by a pretimed signal timing control strategy implemented at an isolated intersection incurring saturated and over-saturated demand varies with actual traffic flows. The volatility of traffic flows often renders pretimed signal control suboptimal when such volatility cannot be predicted by the traffic engineer who designed the control strategy. Even when volatility is somewhat predictable, timing strategies must be made to best accomodate peak flow characteristics, thereby rendering these strategies accepting of a suboptimal situation when near-peak or below-peak demand is encountered. This paper introduces a new computer-based approach for managing signal control at isolated intersections to address these issues. The approach prescribes the application of realtime knowledge based expert system technology.

SOLON: An autonomous vehicle mission planner

Abstract: The State-Operator Logic Machine (SOLON) Planner provides an architecture for effective real-time planning and replanning for an autonomous vehicle. The highlights of the system, which distinguish it from other AI-based planners that have been designed previously, are its hybrid application of state-driven control architecture and the use of both schematic representations and logic programming for the management of its knowledge base. SOLON is designed to provide multiple levels of planning for a single autonomous vehicle which is supplied with a skeletal, partially-specified mission plan at the outset of the vehicle's operations. This mission plan consists of a set of objectives, each of which will be decomposable by the planner into tasks. These tasks are themselves comparatively complex sets of actions which are executable by a conventional real-time control system which does not perform planning but which is capable of making adjustments or modifications to the provided tasks according to constraints and tolerances provided by the Planner. The current implementation of the SOLON is in the form of a real-time simulation of the Planner module of an Intelligent Vehicle Controller (IVC) on-board an autonomous underwater vehicle (AUV). The simulation is embedded within a larger simulator environment known as ICDS (Intelligent Controller Development System) operating on a Symbolics 3645/75 computer.

A Research Plan for Highway Vehicle Navigation Technology

Abstract: This paper describes a proposed research plan to explore the application of advanced technology to highway vehicle navigation. The proposed research addresses navigation, communication, and control technology, benefits of improved vehicle navigation, system requirements, and design and implementation issues. The paper introduces the issues involved in highway vehicle navigation and communication, and discusses recent developments in vehicle navigation technology. The importance of a vigorous program of research in this area is identified, and six near term and ten follow-on projects are described, including provision estimates of the level of effort required.