Copyright (c) 2009 All rights reserved. http://works.bepress.com/pmckerrow Recent documents in Assoc. Prof. P. McKerrow en-us Sun, 31 May 2009 10:32:29 PDT 3600 http://works.bepress.com/pmckerrow/16 http://works.bepress.com/pmckerrow/16 Tue, 24 Feb 2009 17:23:40 PST As an echolocating sensor moves through an environment the pattern of echoes reflected by objects to that sensor changes continuously, creating acoustic flow. Acoustic flow has been observed in both bats and humans. In this paper, we develop a theory of acoustic flow, and discuss measuring it with a Continuous Transmission Frequency Modulated (CTFM) ultrasonic sensor. P. J. McKerrow http://works.bepress.com/pmckerrow/14 http://works.bepress.com/pmckerrow/14 Tue, 24 Feb 2009 17:23:40 PST The development of embedded systems on Macintosh has been constrained by a lack of software tools. In this paper, we look at a number of tools for developing embedded software on a Macintosh host. Also, we examine the advantage of writing embedded applications in high-level, type-safe languages. In this context, we discuss programming PIC micro-controllers in C, Basic Stamps in PBasic and TINI micro-controller in Java. P. J. McKerrow http://works.bepress.com/pmckerrow/15 http://works.bepress.com/pmckerrow/15 Tue, 24 Feb 2009 17:23:40 PST The echo of a chirp of ultrasonic energy from an object contains information about the geometry of that object: relative depth of surfaces and approximate area of those surfaces. A human face has complex geometry that produces a distinctive echo. In this paper, we report initial research into whether there is sufficient information in the echo to recognize a still face. Potential features for classification are identified using a facial model. The classification results for 10 faces encourage future research with a larger number of faces and with moving faces. P. J. McKerrow http://works.bepress.com/pmckerrow/12 http://works.bepress.com/pmckerrow/12 Tue, 24 Feb 2009 17:23:39 PST Directed sensing poses the problem of sensing in specific directions in synchronisation with robot motion while avoiding collisions with objects in other directions. The rebuild of an outdoor mobile robot, with the goal of mimicking a blind person navigating with echolocation, has provided the opportunity to experiment with a state machine based software architecture for landmark navigation. In this paper, we discuss the rebuild of the robot, the software architecture and an initial experiment in collision avoidance. P. J. McKerrow http://works.bepress.com/pmckerrow/13 http://works.bepress.com/pmckerrow/13 Tue, 24 Feb 2009 17:23:39 PST In this paper, we examine the advantage of writing real-time applications and operating systems in typesafe languages, such as Java. In this context, we look at the issues of using Java in real-time systems and the development tools available on Macintosh computers. Finally, we explore the potential of the Sun SPOT system: a credit-card sized Java computer with input/output, and a wireless network, that runs the Squawk JVM. It is planned to be released in Australia in the third quarter of 2007. P. J. McKerrow http://works.bepress.com/pmckerrow/11 http://works.bepress.com/pmckerrow/11 Tue, 24 Feb 2009 17:23:38 PST Most researchers develop real-time applications with C, including programming hardware with C and using a Real Time Operating System (RTOS) that is written in C to manage the task environment. In this paper, we research a different approach by using Java to develop a real-time application. We implement an example real-time project, onboard computation of a coaxial helicopter Lama, with a Java based Sun SPOT to control the hardware and a Java RTOS (JARTOS) running on top of the Sun SPOT to manage the processes. This project enables us to answer several questions regarding to real-time system development with the Sun SPOT. At last, we conclude this paper with the experience we gather during the development. L. Chen http://works.bepress.com/pmckerrow/10 http://works.bepress.com/pmckerrow/10 Tue, 24 Feb 2009 17:23:38 PST Our goal is to develop a navigation system for a mobile robot that mimics human navigation. To achieve this goal the robot has to perceive sufficient information about its environment to determine where there are safe paths to travel. Blind humans using ultrasonic mobility aids have achieved excellent navigation. First, we look at the quality of ultrasonic sensing and its suitability for navigation. Then we describe examples from our research into navigation. The paper finishes with a description of current work on corridor following. P. J. McKerrow http://works.bepress.com/pmckerrow/9 http://works.bepress.com/pmckerrow/9 Thu, 29 May 2008 10:46:02 PDT The Draganflyer is a radio-controlled helicopter. It is powered by 4 rotors and is capable of motion in air in 6 degrees of freedom and of stable hovering. For flying it requires a high degree of skill, with the operator continually making small adjustments. In this paper, we do a theoretical analysis of the dynamics of the Draganflyer in order to develop a model of it from which we can develop a computer control system for stable hovering and indoor flight. P. McKerrow http://works.bepress.com/pmckerrow/8 http://works.bepress.com/pmckerrow/8 Thu, 29 May 2008 10:45:58 PDT Roughness is a characteristic of a surface that is a function of its geometry. Ultrasonic sensing in air provides range, area, and angle information because the surface geometry determines the characteristics of the echo. The authors introduce the "spatial-angle-filter model" to explain the impact of surface roughness on the echo. On the basis of this model, they design a set of features for use in classifying surfaces. The quality of the features and the classification is measured with the Mahalanobis distance. The resultant system is able to achieve 99.73% classification of a set of 12 surfaces using five features. P. J. McKerrow http://works.bepress.com/pmckerrow/7 http://works.bepress.com/pmckerrow/7 Thu, 29 May 2008 10:45:52 PDT Many applications require the sensing of plants. When an ultrasonic sensor insonifies a plant, the resultant echo is the superposition of the echoes from the leaves. As a result, the echo contains information about the geometric structure of the foliage. In this paper, we present a model of sensing that facilitates the extraction of geometric features from the echo for plant classification, recognition and discrimination. We model the echo from a CTFM ultrasonic sensor with the acoustic density profile model. Then, we identify a set of features that represent plant geometric characteristics and use these to perform an inverse transform from echo features to plant geometry. P. McKerrow