1,721,496 research outputs found
A Helicopter named Dolly : behavioural cloning for autonomous helicopter control
No full textThis paper considers the pros and cons of using Behavioural cloning for the development of low-level helicopter automation modules. Over the course of this project several Behavioural cloning approaches have been investigated. The results of the most effective Behavioural cloning approach are then compared to PID modules designed for the same aircraft. The comparison takes into consideration development time, reliability, and control performance. It has been found that Behavioural cloning techniques employing local approximators and a wide state-space coverage during training can produce stabilising control modules in less time than tuning PID controllers. However, performance and reliabity deficits have been found to exist with the Behavioural Cloning, attributable largely to the time variant nature of the dynamics due to the operating environment, and the pilot actions being poor for teaching. The final conclusion drawn here is that tuning PID modules remains superior to behavioural cloning for low-level helicopter automation
Improved joint control using a genetic algorithm for a humanoid robot
No full textThis paper describes experiments conducted in order\ud
to simultaneously tune 15 joints of a humanoid robot. Two Genetic Algorithm (GA) based tuning methods were developed and compared against a hand-tuned solution. The system was tuned in order to minimise tracking error while at the same time achieve smooth joint motion. Joint smoothness is crucial for the accurate calculation of online ZMP estimation, a prerequisite for a closedloop dynamically stable humanoid walking gait. Results in both simulation and on a real robot are presented, demonstrating the superior smoothness performance of the GA based methods
Helicopter automation using a low-cost sensing system
No full textThis paper details the design of an autonomous helicopter control system using a low cost sensor suite. Control is maintained using simple nested PID loops. Aircraft attitude, velocity, and height is estimated using an in-house designed IMU and vision system. Information is combined using complimentary filtering. The aircraft is shown to be stabilised and responding to high level demands on all axes, including heading, height, lateral velocity and longitudinal velocity
Localization and place recognition using an ultra-wide band (UWB) radar
No full textThis paper presents an approach to mobile robot localization, place recognition and loop closure using a monostatic ultra-wide band (UWB) radar system. The UWB radar is a time-of-flight based range measurement sensor that transmits short pulses and receives reflected waves from objects in the environment. The main idea of the poposed localization method is to treat the received waveform as a signature of place. The resulting echo waveform is very complex and highly depends on the position of the sensor with respect to surrounding objects. On the other hand, the sensor receives similar waveforms from the same positions.Moreover, the directional characteristics of dipole antenna is almost omnidirectional. Therefore, we can localize the sensor position to find similar waveform from waveform database. This paper proposes a place recognitionmethod based on waveform matching, presents a number of experiments that illustrate the high positon estimation accuracy of our UWB radar-based localization system, and shows the resulting loop detection performance in a typical indoor office environment and a forest
Optimal analysis of fragmented irrigation projects
No full textA new approach to the appraisal of 'fragmented' agricultural development projects in the poorer so-called 'Less Developed Countries' is developed from a critical examination of contemporary social cost benefit analysis procedures for project appraisal in such countries.In what are here termed 'fragmented' projects, fragmentation, although essentially physical, most importantly applies to decision making. This is predominantly decentralized since by virtue of the circumstances being considered land and labour are in the hands of numerous subsistence smallholders. Central control is limited to development inputs which typically might include infrastructural improvements, improved and more equitable availability of credit, the introduction of new technology (such as irrigation) and allied to all of these, the provision of extension. That the history of such projects has been characterized by a marked lack of success is seen to be' largely attributable to the current lack of techniques for dealing with the conceptually unique problems that inherently arise in the appraisal and the optimal *formulation and planning of this type of development. ixCentral to the methodology proposed for the analysis of fragmented projects is an analytical model that integrates the physical and socio-economic circumstances of the individual farmer in order to predict his response to development stimulae. By simulating the on-going inter temporal response of a representative group of farmers to their resultant individual and common circumstances the boundaries of a viable project can be investigated and subject to constraints and development objectives the optimal project identified. The central model was developed and is tested using data from a fragmented project in which the author was involved.</p
A Coordination Model for Exploratory Multi-View Visualization
Full text linkIn this paper, we present a coordination model for exploratory multi-view visualization. We base our work on current research in exploratory visualization and other disciplines. Our model is based on sharing abstract objects such as the visualization parameters of the dataflow model to achieve coordinated exploratory tasks in multiple views. This model describes how current coordinations in exploratory visualization work and allows novel coordinations to be constructed
Third International Conference on Coordinated and Multiple Views in Exploratory Visualization (CMV 2005)
No full textCMV 2005 is the third conference on Coordinated and Multiple Views in Exploratory Visualization. The aim of this conference is to bring together top researchers in the area, to stimulate discussion and debate ideas and future opportunities. This conference focuses on all aspects of multiple-view techniques including: multiform views, tight coupling, linked dynamic interaction, multiple views for interactive steering, and spreadsheet based visualisation techniques. The emphasis is on generating and manipulating multiple views and coordinating information between them. It is clear why users wish to explore, interact and interrogate their data. They are often faced with unknown data of huge proportions, with many variables and multiple dimensions. As such they are faced with an insurmountable comprehension task. Multiple views that are coordinated together can enhance and aid the user in this process. The first CMV conference was held in 2003. Over the last few years this field has developed and grown. In fact, many of the papers presented this year detail how multiple linked views can be used to solve a particular problem in a particular application domain. This is certainly an exciting time as we see CMV techniques and principles applied to solve real problems. But, there is still much work to be done. Not only discovering how to appropriately apply these ideas to new application domains, but to discover more effective CMV techniques and designs. One aspect of this research is the study and use of 'sharing things' for exploratory visualisation. Taking this simplistic view, we may learn from concepts such as sharing hardware devices in a computer system or managing, delegating roles in a human organization or collaborative support. During last year's conference we had an open discussion about the status of the area; it was generally agreed that we were reasonable at some aspects, such as manipulation (zoom, brush, etc.) and simultaneous exploration, but needed more effort into challenges such as: validation and evaluation of the effectiveness and appropriateness of the technique (e.g., whether two or more views are best, when one technique should be used over another), measuring quantities (especially measuring and comparing quantities over multiple windows), managing the whole visualization exploration, and integrating temporal data. It is encouraging that some of these challenges are being addressed in the papers of this volume. Indeed, this volume presents the current state of the art in CMV and allows the reader to discover more about this exciting and developing area
Philanthropy, market creation, and enterprise development
No full textThe institutions of philanthropic giving and the commercial market are traditionally perceived as distinct. But philanthropic resources are increasingly flowing into both for-profit and non-profit market-based organisations, and there is a new focus upon philanthropy's role in creating or repairing markets in order to achieve social and economic impact. This chapter describes this market support role of philanthropy and analyses in detail two distinct modes of action: a market creation function, modelled on the mainstream capitalist market, that seeks to enable the development of innovative market structures and products that can resolve social problems at scale; and a ‘community enterprise’ function, whereby philanthropic funding develops the commercial capacity of locally based social enterprises and businesses. The chapter recognises normative criticisms of philanthropy's role in market development, but argues that there is an important social policy function for philanthropy in repairing specific absences and failures of both market and state
The social justice approach in philanthropy
No full textSocial justice philanthropy is a collection of diverse discourses and approaches that, in its strongest form, demands radical reform of societal structures according to critical understandings of power and equity. This chapter introduces an innovative conceptual framework that isolates the essential characteristics of social justice philanthropy and enables identification and comparison of the various actors in this field – from philanthropic institutions emerging within marginalised communities to elite foundations redirecting their activities towards some idea of social justice. It describes the activities of these actors across social policy fields, highlighting the use of philanthropic resources to support social activism; it considers how social justice approaches challenge the mechanisms and power dynamics of mainstream philanthropy itself. The chapter concludes by identifying substantive implications for social policy: the centrality of government and policy as a field of philanthropic action; the resourcing of alternative public spheres of discourse and protest; holding state and market to account; and challenges to constructions of effectiveness and evidence within social policy
Natural dark matter within the minimal supersymmetric standard model
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