Harry H. Cheng

A Review of the Applications of Agent Technology in Traffic and Transportation Systems

The agent computing paradigm is rapidly emerging as one of the powerful technologies for the development of large-scale distributed systems to deal with the uncertainty in a dynamic environment. The domain of traffic and transportation systems is well suited for an agent-based approach because transportation systems are usually geographically distributed in dynamic changing environments. Our literature survey shows that the techniques and methods resulting from the field of agent and multiagent systems have been applied to many aspects of traffic and transportation systems, including modeling and simulation, dynamic routing and congestion management, and intelligent traffic control. This paper examines an agent-based approach and its applications in different modes of transportation, including roadway, railway, and air transportation. This paper also addresses some critical issues in developing agent-based traffic control and management systems, such as interoperability, flexibility, and extendibility. Finally, several future research directions toward the successful deployment of agent technology in traffic and transportation systems are discussed.

A real-time laser-based detection system for measurement of delineations of moving vehicles

In current practice, quantitative traffic data are most commonly acquired from inductive loops. In addition, video-image processing or time-of-flight laser systems can be used. These methods all have problems associated with them. We have developed a nonintrusive laser-based detection system for measurement of vehicle travel time. The basic detector unit consists of a fan angle laser and a photodetector array positioned above the plane of detection. This detection system is able to determine the length and width of moving objects in real time with high resolution, with the highest resolution measurements being associated with object lengths. This information is used to differentiate similar objects and can be used later for re-identification of individual objects or object groups, providing a real measure of travel time between detection sites.

Web based control system design and analysis

The World Wide Web has provided an opportunity for design and analysis of control systems through the Internet. An increasing number of Web-based software packages have been developed to enhance the teaching and design of control systems. A Web-based interactive control design and analysis system (WCDAS) based on Ch (which is a C/C++ interpreter) and Ch control systems toolkit is developed. Most functions in the system support both continuous-time and discrete-time linear time-invariant systems modeled in state space, transfer functions, or zero-pole-gain representation. Users can select a design and analysis method and specify system model type, system type and system parameters in the Web browser. These data are transferred to the server for numerical computation, and the simulation results are sent back to the client through the common gateway interface (CGI) using the Ch interpretative environment. Because both CGI scripts and simulation programs are written in Ch, data exchange between client and server is easily achieved. The system is available for use through the Web without any software installation, system configuration, or programming. This Web-based system is ideal for teaching as well as for solving practical problems in control systems design and analysis. The software packages Ch, CCST and WCDAS are available for downloading on the Web. The design, implementation and salient features of WCDAS are described in this article.

Design of iMobot, an intelligent reconfigurable mobile robot with novel locomotion

The design and novel features of a reconfigurable modular robot, called iMobot, with four controllable degrees of freedom is presented in this paper. iMobot, which is designed for search and rescue operations as well as other applications such as research and teaching, has versatile locomotion, including a unique feature of driving as though with wheels and lifting itself into a camera platform. Future work is envisioned for using these modules in clusters to achieve advanced mobility. The accompanying video demonstrates the various locomotion of the modular robot.

Development and field test of a laser-based nonintrusive detection system for identification of vehicles on the highway

A real-time laser-based nonintrusive detection system has been developed for the measurement of true travel time of vehicles on the highway. The detection system uses a laser line that is projected onto the ground as a probe. The reflected light is collected and focused into a photodiode array by an optical system. Vehicle presence is detected based on the absence of reflected laser light. By placing two identical laser/sensor pairs at a known distance apart, the speeds of both the front and rear of a vehicle are measured based on the times when each sensor is triggered. The length of each vehicle is determined by using these speed measurements and the residence time of the vehicle under each sensor. Using real-time software, the speed, acceleration, and length of a detected vehicle can be calculated and displayed simultaneously. A new prototype system has been tested on the highway with different types of vehicles and scenarios, and the results are presented here. The tests have also been carried out for different weather conditions and road materials. The results indicate that the laser system operates well under real highway conditions.

A Mobile Agent-Based Framework for Flexible Automation Systems

Modern manufacturing systems are increasingly becoming highly dynamic due to the integration with advanced information technology in response to rapid changes in products and market conditions. A more flexible platform is critically needed for developing a new generation of manufacturing systems in order to address the challenges of uncertainty and flexibility requirements. This paper presents a mobile agent-based framework that supports dynamic deployment of control algorithms and tasks in automation systems. The framework is based on a mobile agent system called Mobile-C. It uses Ch, an embeddable interpretive C/C++ environment for mobile agent execution. Since Ch has been ported to most existing computing platforms, the framework can control automation systems that work in different operating systems. This mobile agent-based framework has been applied to the control of an automation work cell. Using an automaton package in Ch as a middleware, automation tasks can be described as high-level control programs and are portable to heterogeneous mechatronic devices that comprise the automation cell. The validation of the dynamic deployment of different tasks has been conducted in an experimental automation work cell that consists of a Puma 560, an IBM 7575, and a conveyor system. The results show that the mobile agent approach can effectively deploy and execute new control algorithms and tasks as mobile agents on any subsystem in a network.

Programming with dual numbers and its applications in mechanisms design

Dual numbers are expressed in the form x+ɛy where ɛ2. Dual metanumbers are defined in this paper as DualZero, DualInf and DualNaN. The extended dual plane and the extended finite dual plane are introduced to describe dual numbers and dual metanumbers. Handling of dual numbers in the CH programming language is presented. The I/O, arithmetic and relational operations, and built-in mathematical functions are defined for both dual numbers and dual metanumbers. As a result of polymorphism, the syntaxes of dual arithmetic and relational operations, and built-in dual functions are the same as those for real and complex numbers in the CH programming language. The valid lvalues related to dual numbers in CH are defined. The computation of the motion screw for a rigid-body displacement is used as an example to illustrate the creation of users dual functions. The efficacy of CH programming with dual numbers is demonstrated by displacement analysis of an RCCC mechanism. For the first time, dual data is handled as a built-in data type in a general-purpose computer programming language. Programming with dual numbers in CH is simpler than in any other computer programming language.

XML-based agent communication, migration and computation in mobile agent systems

This article presents the research work that exploits using XML (Extensible Markup Language) to represent different types of information in mobile agent systems, including agent communication messages, mobile agent messages, and other system information. The goal of the research is to build a programmable information base in mobile agent systems through XML representations. The research not only studies using XML in binary agent system space such as representing agent communication messages and mobile agent messages, but also explores interpretive XML data processing to avoid the need of an interface layer between script mobile agents and system data represented in XML. These XML-based information representations have been implemented in Mobile-C, a FIPA (The Foundation for Intelligent Physical Agents) compliant mobile agent platform. Mobile-C uses FIPA ACL (Agent Communication Language) messages for both inter-agent communication and inter-platform migration. Using FIPA ACL messages for agent migration in FIPA compliant agent systems simplifies agent platform, reduces development effort, and easily achieves inter-platform migration through well-designed communication mechanisms provided in the system. The ability of interpretive XML data processing allows mobile agents in Mobile-C directly accessing XML data information without the need of an extra interface layer.

Object-oriented cam design through the internet

AbstractWe have developed a Web-based interactive cam design package under the programming paradigm of the