In the Rough : In-Field evaluation of an autonomous vehicle for golf course maintenance

Maintenance is a time consuming and expensive task for any golf course or driving range manager. For a golf course the primary tasks are grass mowing and maintenance (fertilizer and herbicide spreading), while for a driving range mowing, maintenance and ball collection are required. All these tasks require an operator to drive a vehicle along paths which are generally predefined. This paper presents some preliminary in-field tsting results for an automated tractor vehicle performing golf ball collection on an actual driving range, and mowing on difficult unstructured terrain.

Multi-robot control in highly dynamic, competitive environments

The control and coordination of multiple mobile robots is a challenging task; particularly in environments with multiple, rapidly moving obstacles and agents. This paper describes a robust approach to multi-robot control, where robustness is gained from competency at every layer of robot control. The layers are: (i) a central coordination system (MAPS), (ii) an action system (AES), (iii) a navigation module, and (iv) a low level dynamic motion control system. The multi-robot coordination system assigns each robot a role and a sub-goal. Each robots action execution system then assumes the assigned role and attempts to achieve the specified sub-goal. The robots navigation system directs the robot to specific goal locations while ensuring that the robot avoids any obstacles. The motion system maps the heading and speed information from the navigation system to force-constrained motion. This multi-robot system has been extensively tested and applied in the robot soccer domain using both centralized and distributed coordination.

A matter of confidence : privacy compliance for connected-up enterprises

Governments around the world are increasingly investing in information and communications technology (ICT) as a means of improving service delivery to citizens. Government ICT adoption is also being driven by a desire to streamline information accessibility and information flows within government - both between different levels of government and between different departments at the same level. Increasing the availability of information internally and to citizens has clear and compelling benefits but it also carries risks that must be carefully managed. This talk will examine the implications of such E-government initiatives for a range of compliance obligations, with a focus on information privacy. It will review recent developments in the area of systems-based enforcement of privacy policies and the particular privacy challenges presented by the aggregation of geospatial information.

Indentation size effect and strain rate sensitivity of nanocrystalline Mg-Al alloys

Deformation Behaviour of microcrystalline (mc) and nanocrystalline (nc) Mg-5%Al alloys produced by hot extrusion of ball-milled powders were investigated using instrumented indentation tests. The hardness values of the mc and nc metals exhibited indentation size effect (ISE), with nc alloys showing weaker ISE. The highly localized dislocation activities resulted in a small activation volume, hence enhanced strain rate sensitivity. Relative higher strain rate sensitivity and the negative Hall-Petch Relationship suggested the increasingly important role of grain boundary mediated mechanisms when the grain size decreased to nanometer region.

The nonconceptual gateway to early word learning

My research investigates why nouns are learned disproportionately more frequently than other kinds of words during early language acquisition (Gentner, 1982; Gleitman, et al., 2004). This question must be considered in the context of cognitive development in general. Infants have two major streams of environmental information to make meaningful: perceptual and linguistic. Perceptual information flows in from the senses and is processed into symbolic representations by the primitive language of thought (Fodor, 1975). These symbolic representations are then linked to linguistic input to enable language comprehension and ultimately production. Yet, how exactly does perceptual information become conceptualized? Although this question is difficult, there has been progress. One way that children might have an easier job is if they have structures that simplify the data. Thus, if particular sorts of perceptual information could be separated from the mass of input, then it would be easier for children to refer to those specific things when learning words (Spelke, 1990; Pylyshyn, 2003). It would be easier still, if linguistic input was segmented in predictable ways (Gentner, 1982; Gleitman, et al., 2004) Unfortunately the frequency of patterns in lexical or grammatical input cannot explain the cross-cultural and cross-linguistic tendency to favor nouns over verbs and predicates. There are three examples of this failure: 1) a wide variety of nouns are uttered less frequently than a smaller number of verbs and yet are learnt far more easily (Gentner, 1982); 2) word order and morphological transparency offer no insight when you contrast the sentence structures and word inflections of different languages (Slobin, 1973) and 3) particular language teaching behaviors (e.g. pointing at objects and repeating names for them) have little impact on children's tendency to prefer concrete nouns in their first fifty words (Newport, et al., 1977). Although the linguistic solution appears problematic, there has been increasing evidence that the early visual system does indeed segment perceptual information in specific ways before the conscious mind begins to intervene (Pylyshyn, 2003). I argue that nouns are easier to learn because their referents directly connect with innate features of the perceptual faculty. This hypothesis stems from work done on visual indexes by Zenon Pylyshyn (2001, 2003). Pylyshyn argues that the early visual system (the architecture of the "vision module") segments perceptual data into pre-conceptual proto-objects called FINSTs. FINSTs typically correspond to physical things such as Spelke objects (Spelke, 1990). Hence, before conceptualization, visual objects are picked out by the perceptual system demonstratively, like a finger pointing indicating ‘this’ or ‘that’. I suggest that this primitive system of demonstration elaborates on Gareth Evan's (1982) theory of nonconceptual content. Nouns are learnt first because their referents attract demonstrative visual indexes. This theory also explains why infants less often name stationary objects such as plate or table, but do name things that attract the focal attention of the early visual system, i.e., small objects that move, such as ‘dog’ or ‘ball’. This view leaves open the question how blind children learn words for visible objects and why children learn category nouns (e.g. 'dog'), rather than proper nouns (e.g. 'Fido') or higher taxonomic distinctions (e.g. 'animal').

Signalling layout for fixed-block railway lines with real-coded genetic algorithms.

Signalling layout design is one of the keys to railway operations with fixed-block signalling system and it also carries direct effect on overall train efficiency and safety. Based on an analysis to system objectives, this paper presents an optimization model with two objectives in order to devise an efficient signalling layout scheme. Taking into account the present railway line design practices in China, the paper describes steps of the computer-based signalling layout optimisation with real-coded genetic algorithms. A computer-aided system, based on train movement simulator, has also been employed to assist the optimisation process. A case study on a practical railway line has been conducted to make comparisons between the proposed GA-based approach and the current practices. The results illustrate the improved performance of the proposed approach in reducing signal block joints and shortening minimum train service headway.

A practical implementation of a continuous isotropic spherical omnidirectional drive

This paper presents a continuous isotropic spherical omnidirectional drive mechanism that is efficient in its mechanical simplicity and use of volume. Spherical omnidirectional mechanisms allow isotropic motion, although many are limited from achieving true isotropic motion by practical mechanical design considerations. The mechanism presented in this paper uses a single motor to drive a point on the great circle of the sphere parallel to the ground plane, and does not require a gearbox. Three mechanisms located 120 degrees apart provide a stable drive platform for a mobile robot. Results show the omnidirectional ability of the robot and demonstrate the performance of the spherical mechanism compared to a popular commercial omnidirectional wheel over edges of varying heights and gaps of varying widths.

Indigenous research and broader issues in the Academy

The Rudd Labour Government rode to power in Australia on the education promise of 'an education revolution'. The term 'education revolution' carries all the obligatory marketing metaphors that an aspirant government might want recognised by the general public on the eve government came to power however in revolutionary terms it fades into insignificance in comparison to the real revolution in Australian education. This revolution simply put is to elevate Indigenous Knowledge Systems, in Australian Universities. In the forty three years since the nation setting Referendum of 1967 a generation has made a beach head on the educational landscape. Now a further generation who having made it into the field of higher degrees yearn for the ways and means to authentically marshal Indigenous knowledge? The Institute of Koorie Education at Deakin has for over twenty years not only witnessed the transition but is also a leader in the field. With the appointment of two Chairs of Indigenous Knowledge Systems to build on to its already established research profile the Institute moved towards what is the 'real revolution' in education – the elevation of Indigenous Knowledge as a legitimate knowledge system. This paper lays out the Institute of Koorie Education‘s Research Plan and the basis of an argument put to the academy that will be the driver for this pursuit.

A general-purpose simulator for train operations

Computer simulation has been widely accepted as an essential tool for the analysis of many engineering systems. It is nowadays perceived to be the most readily available and feasible means of evaluating operations in real railway systems. Based on practical experience and theoretical models developed in various applications, this paper describes the design of a general-purpose simulation system for train operations. Its prime objective is to provide a single comprehensive computer-aided engineering tool for most studies on railway operations so that various aspects of the railway systems with different operation characteristics can be investigated and analysed in depth. This system consists of three levels of simulation. The first is a single-train simulator calculating the running time of a train between specific points under different track geometry and traction conditions. The second is a dual-train simulator which is to find the minimum headway between two trains under different movement constraints, such as signalling systems. The third is a whole-system multi-train simulator which carries out process simulation of the real operation of a railway system according to a practical or planned train schedule or headway; and produces an overall evaluation of system performance.

Governmentality and the reflection of legal educators : assessment practices as a case study

This paper presents a conceptual framework, informed by Foucault’s work on governmentality, which allows for new kinds of reflection on the practice of legal education. Put simply, this framework suggests that legal education can be understood as a form of government that relies on a specific rationalisation and programming of the activities of legal educators, students, and administrators, and is implemented by harnessing specific techniques and bodies of ‘know-how’. Applying this framework to assessment at three Australian law schools, this paper highlights how assessment practices are rationalised, programmed, and implemented, and points out how this government shapes students’ legal personae. In particular, this analysis focuses on the governmental effects of pedagogical discourses that are dominant within the design and scholarship of legal education. It demonstrates that the development of pedagogically-sound regimes of assessment has contributed to a reformulation of the terrain of government, by providing the conditions under which forms of legal personae may be more effectively shaped, and extending the power relations that achieve this. This analysis provides legal educators with an original way of reflecting on the power effects of teaching the law, and new opportunities for thinking about what is possible in legal education.

Governing depression in law students and the shaping of legal personae

Since a recent Australian study found that university law students experience higher rates of depression than medical students and legal professionals (Kelk et al. 2009), the mental health of law students has increasingly become a target of government. To date, however, there has been no attempt to analyse these practices as an activity of government in advanced liberal societies. This paper addresses this imbalance by providing an initial analytics of the government of depression in law schools. It demonstrates how students are responsibilised to manage the risks and uncertainties of legal education by constructing resilient forms of personal and professional personae. It highlights that, in order to avoid depression, students are encouraged to shape not just their minds and bodies according to psychological and biomedical discourses, but are also to govern their ethical dispositions and become virtuous persons. This paper also argues that these forms of government are tied to advanced liberal forms of rule, as they position the law student as the locus of responsibility for depression, imply that depression is caused by an individual failing, and entrench students within responsibilising and entrepreneurial forms of subjectivity.

A further step in the modelling of the mechanical behaviour of bagasse

A better understanding of the behaviour of prepared cane and bagasse during the crushing process is believed to be an essential prerequisite for further improvements to the crushing process. Improvements could be made, for example, in throughput, sugar extraction, and bagasse moisture. The ability to model the mechanical behaviour of bagasse as it is squeezed in a milling unit to extract juice would help identify how to improve the current process to reduce final bagasse moisture. However an adequate mechanical model for bagasse is currently not available. Previous investigations have proven with certainty that juice flow through bagasse obeys Darcy’s permeability law, that the grip of the rough surface of the grooves on the bagasse can be represented by the Mohr- Coulomb failure criterion for soils, and that the internal mechanical behaviour of the bagasse is critical state behaviour similar to that for sand and clay. Current Finite Element Models (FEM) available in commercial software have adequate permeability models. However, the same commercial software do not contain an adequate mechanical model for bagasse. Progress has been made in the last ten years towards implementing a mechanical model for bagasse in finite element software code. This paper builds on that progress and carries out a further step towards obtaining an adequate material model.

Remediation strategies of shaft and common mode voltages in adjustable speed drive systems

AC motors are largely used in a wide range of modern systems, from household appliances to automated industry applications such as: ventilations systems, fans, pumps, conveyors and machine tool drives. Inverters are widely used in industrial and commercial applications due to the growing need for speed control in ASD systems. Fast switching transients and the common mode voltage, in interaction with parasitic capacitive couplings, may cause many unwanted problems in the ASD applications. These include shaft voltage and leakage currents. One of the inherent characteristics of Pulse Width Modulation (PWM) techniques is the generation of the common mode voltage, which is defined as the voltage between the electrical neutral of the inverter output and the ground. Shaft voltage can cause bearing currents when it exceeds the amount of breakdown voltage level of the thin lubricant film between the inner and outer rings of the bearing. This phenomenon is the main reason for early bearing failures. A rapid development in power switches technology has lead to a drastic decrement of switching rise and fall times. Because there is considerable capacitance between the stator windings and the frame, there can be a significant capacitive current (ground current escaping to earth through stray capacitors inside a motor) if the common mode voltage has high frequency components. This current leads to noises and Electromagnetic Interferences (EMI) issues in motor drive systems. These problems have been dealt with using a variety of methods which have been reported in the literature. However, cost and maintenance issues have prevented these methods from being widely accepted. Extra cost or rating of the inverter switches is usually the price to pay for such approaches. Thus, the determination of cost-effective techniques for shaft and common mode voltage reduction in ASD systems, with the focus on the first step of the design process, is the targeted scope of this thesis. An introduction to this research – including a description of the research problem, the literature review and an account of the research progress linking the research papers – is presented in Chapter 1. Electrical power generation from renewable energy sources, such as wind energy systems, has become a crucial issue because of environmental problems and a predicted future shortage of traditional energy sources. Thus, Chapter 2 focuses on the shaft voltage analysis of stator-fed induction generators (IG) and Doubly Fed Induction Generators DFIGs in wind turbine applications. This shaft voltage analysis includes: topologies, high frequency modelling, calculation and mitigation techniques. A back-to-back AC-DC-AC converter is investigated in terms of shaft voltage generation in a DFIG. Different topologies of LC filter placement are analysed in an effort to eliminate the shaft voltage. Different capacitive couplings exist in the motor/generator structure and any change in design parameters affects the capacitive couplings. Thus, an appropriate design for AC motors should lead to the smallest possible shaft voltage. Calculation of the shaft voltage based on different capacitive couplings, and an investigation of the effects of different design parameters are discussed in Chapter 3. This is achieved through 2-D and 3-D finite element simulation and experimental analysis. End-winding parameters of the motor are also effective factors in the calculation of the shaft voltage and have not been taken into account in previous reported studies. Calculation of the end-winding capacitances is rather complex because of the diversity of end winding shapes and the complexity of their geometry. A comprehensive analysis of these capacitances has been carried out with 3-D finite element simulations and experimental studies to determine their effective design parameters. These are documented in Chapter 4. Results of this analysis show that, by choosing appropriate design parameters, it is possible to decrease the shaft voltage and resultant bearing current in the primary stage of generator/motor design without using any additional active and passive filter-based techniques. The common mode voltage is defined by a switching pattern and, by using the appropriate pattern; the common mode voltage level can be controlled. Therefore, any PWM pattern which eliminates or minimizes the common mode voltage will be an effective shaft voltage reduction technique. Thus, common mode voltage reduction of a three-phase AC motor supplied with a single-phase diode rectifier is the focus of Chapter 5. The proposed strategy is mainly based on proper utilization of the zero vectors. Multilevel inverters are also used in ASD systems which have more voltage levels and switching states, and can provide more possibilities to reduce common mode voltage. A description of common mode voltage of multilevel inverters is investigated in Chapter 6. Chapter 7 investigates the elimination techniques of the shaft voltage in a DFIG based on the methods presented in the literature by the use of simulation results. However, it could be shown that every solution to reduce the shaft voltage in DFIG systems has its own characteristics, and these have to be taken into account in determining the most effective strategy. Calculation of the capacitive coupling and electric fields between the outer and inner races and the balls at different motor speeds in symmetrical and asymmetrical shaft and balls positions is discussed in Chapter 8. The analysis is carried out using finite element simulations to determine the conditions which will increase the probability of high rates of bearing failure due to current discharges through the balls and races.

The Spartan-3E Tutorial 1 : Introduction to FPGA Programming, Version 1.0

This tutorial is designed to help new users become familiar with using the Spartan-3E board. The tutorial steps through the following: writing a small program in VHDL which carries out simple combinational logic; connecting the program inputs and outputs to the switches, buttons and LEDs on the Spartan-3E board; and downloading the program to the Spartan-3E board using the Project Navigator software.

Patterns

In recent years there has been widespread interest in patterns, perhaps provoked by a realisation that they constitute a fundamental brain activity and underpin many artificial intelligence systems. Theorised concepts of spatial patterns including scale, proportion, and symmetry, as well as social and psychological understandings are being revived through digital/parametric means of visualisation and production. The effect of pattern as an ornamental device has also changed from applied styling to mediated dynamic effect. The interior has also seen patterned motifs applied to wall coverings, linen, furniture and artefacts with the effect of enhancing aesthetic appreciation, or in some cases causing psychological and/or perceptual distress (Rodemann 1999). ----- ----- While much of this work concerns a repeating array of surface treatment, Philip Ball’s The Self- Made Tapestry: Pattern Formation in Nature (1999) suggests a number of ways that patterns are present at the macro and micro level, both in their formation and disposition. Unlike the conventional notion of a pattern being the regular repetition of a motif (geometrical or pictorial) he suggests that in nature they are not necessarily restricted to a repeating array of identical units, but also include those that are similar rather than identical (Ball 1999, 9). From his observations Ball argues that they need not necessarily all be the same size, but do share similar features that we recognise as typical. Examples include self-organized patterns on a grand scale such as sand dunes, or fractal networks caused by rivers on hills and mountains, through to patterns of flow observed in both scientific experiments and the drawings of Leonardo da Vinci.