83 resultados para shadow fading
Resumo:
In outdoor environments shadows are common. These typically strong visual features cause considerable change in the appearance of a place, and therefore confound vision-based localisation approaches. In this paper we describe how to convert a colour image of the scene to a greyscale invariant image where pixel values are a function of underlying material property not lighting. We summarise the theory of shadow invariant images and discuss the modelling and calibration issues which are important for non-ideal off-the-shelf colour cameras. We evaluate the technique with a commonly used robotic camera and an autonomous car operating in an outdoor environment, and show that it can outperform the use of ordinary greyscale images for the task of visual localisation.
Resumo:
Agent-based modelling (ABM), like other modelling techniques, is used to answer specific questions from real world systems that could otherwise be expensive or impractical. Its recent gain in popularity can be attributed to some degree to its capacity to use information at a fine level of detail of the system, both geographically and temporally, and generate information at a higher level, where emerging patterns can be observed. This technique is data-intensive, as explicit data at a fine level of detail is used and it is computer-intensive as many interactions between agents, which can learn and have a goal, are required. With the growing availability of data and the increase in computer power, these concerns are however fading. Nonetheless, being able to update or extend the model as more information becomes available can become problematic, because of the tight coupling of the agents and their dependence on the data, especially when modelling very large systems. One large system to which ABM is currently applied is the electricity distribution where thousands of agents representing the network and the consumers’ behaviours are interacting with one another. A framework that aims at answering a range of questions regarding the potential evolution of the grid has been developed and is presented here. It uses agent-based modelling to represent the engineering infrastructure of the distribution network and has been built with flexibility and extensibility in mind. What distinguishes the method presented here from the usual ABMs is that this ABM has been developed in a compositional manner. This encompasses not only the software tool, which core is named MODAM (MODular Agent-based Model) but the model itself. Using such approach enables the model to be extended as more information becomes available or modified as the electricity system evolves, leading to an adaptable model. Two well-known modularity principles in the software engineering domain are information hiding and separation of concerns. These principles were used to develop the agent-based model on top of OSGi and Eclipse plugins which have good support for modularity. Information regarding the model entities was separated into a) assets which describe the entities’ physical characteristics, and b) agents which describe their behaviour according to their goal and previous learning experiences. This approach diverges from the traditional approach where both aspects are often conflated. It has many advantages in terms of reusability of one or the other aspect for different purposes as well as composability when building simulations. For example, the way an asset is used on a network can greatly vary while its physical characteristics are the same – this is the case for two identical battery systems which usage will vary depending on the purpose of their installation. While any battery can be described by its physical properties (e.g. capacity, lifetime, and depth of discharge), its behaviour will vary depending on who is using it and what their aim is. The model is populated using data describing both aspects (physical characteristics and behaviour) and can be updated as required depending on what simulation is to be run. For example, data can be used to describe the environment to which the agents respond to – e.g. weather for solar panels, or to describe the assets and their relation to one another – e.g. the network assets. Finally, when running a simulation, MODAM calls on its module manager that coordinates the different plugins, automates the creation of the assets and agents using factories, and schedules their execution which can be done sequentially or in parallel for faster execution. Building agent-based models in this way has proven fast when adding new complex behaviours, as well as new types of assets. Simulations have been run to understand the potential impact of changes on the network in terms of assets (e.g. installation of decentralised generators) or behaviours (e.g. response to different management aims). While this platform has been developed within the context of a project focussing on the electricity domain, the core of the software, MODAM, can be extended to other domains such as transport which is part of future work with the addition of electric vehicles.
Resumo:
Australia's economic growth and national identity have been widely celebrated as being founded on the nation's natural resources. With the golden era of pastoralism fading into the distance, a renewed love affair with primary industries has been much lauded, particularly by purveyors of neoliberal ideology. The considerable wealth generated by resource extraction has, despite its environmental and social record, proved seductive to the university sector. The mining industry is one of a number of industries and sectors (alongside pharmaceutical, chemical and biotechnological) that is increasingly courting Australian universities. These new public-private alliances are often viewed as the much-needed cash cow to bridge the public funding shortfall in the tertiary sector. However, this trend also raises profound questions about the capacity of public good institutions, as universities were once assumed to be, to maintain institutional independence and academic freedoms.
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A simple but accurate method for measuring the Earth’s radius using a video camera is described. A video camera was used to capture a shadow rising up the wall of a tall building at sunset. A free program called ImageJ was used to measure the time it took the shadow to rise a known distance up the building. The time, distance and length of the sidereal day were used to calculate the radius of the Earth. The radius was measured as 6394.3 +/- 118 km, which is within 1.8% of the accepted average value of 6371 km and well within the experimental error. The experiment is suitable as a high school or university project and should produce a value for Earth’s radius within a few per cent at latitudes towards the equator, where at some times of the year the ecliptic is approximately normal to the horizon.
Resumo:
This paper describes the design and implementation of a wireless neural telemetry system that enables new experimental paradigms, such as neural recordings during rodent navigation in large outdoor environments. RoSco, short for Rodent Scope, is a small lightweight user-configurable module suitable for digital wireless recording from freely behaving small animals. Due to the digital transmission technology, RoSco has advantages over most other wireless modules of noise immunity and online user-configurable settings. RoSco digitally transmits entire neural waveforms for 14 of 16 channels at 20 kHz with 8-bit encoding which are streamed to the PC as standard USB audio packets. Up to 31 RoSco wireless modules can coexist in the same environment on non-overlapping independent channels. The design has spatial diversity reception via two antennas, which makes wireless communication resilient to fading and obstacles. In comparison with most existing wireless systems, this system has online user-selectable independent gain control of each channel in 8 factors from 500 to 32,000 times, two selectable ground references from a subset of channels, selectable channel grounding to disable noisy electrodes, and selectable bandwidth suitable for action potentials (300 Hz–3 kHz) and low frequency field potentials (4 Hz–3 kHz). Indoor and outdoor recordings taken from freely behaving rodents are shown to be comparable to a commercial wired system in sorting for neural populations. The module has low input referred noise, battery life of 1.5 hours and transmission losses of 0.1% up to a range of 10 m.
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The most widely used introduction to the Australian media, fully updated to reflect the increasing prominence of the internet in the communication and entertainment industries. Description Traditional media are being reshaped by digital technologies. The funding model for quality journalism has been undermined by the drift of advertising online, demarcations between different forms of media are rapidly fading, and audiences have fragmented. We can catch up with our favourite TV show on a tablet, social media can be more important than mainstream radio in a crisis, and organisations large and small have become publishers in their own right on apps. Nevertheless mainstream media remain powerful. The Media and Communications in Australia offers a systematic introduction to this dynamic field. Fully updated and revised to take account of recent developments, this fourth edition outlines the key media industries and explains how communications technologies are impacting on them. It provides a thorough overview of the main approaches taken in studying the media, and includes an expanded 'issues' section with new chapters on social media, gaming, apps, the environment, media regulation, ethics and privacy. With contributions from some of Australia's best researchers and teachers in the field, The Media and Communications in Australia remains the most comprehensive and reliable introduction to media and communications available. It is an ideal student text, and a reference for teachers of media and anyone interested in this influential industry.
Resumo:
A salient but rarely explicitly studied characteristic of interfirm relationships is that they can intentionally be formed for finite periods of time. What determines firms' intertemporal choices between different alliance time horizons? Shadow of the future theorists suggest that when an alliance has an explicitly set short-term time frame, there is an increased risk that partners may behave opportunistically. This does not readily explain the high incidence of time-bound alliances being formed. Reconciling insights from the shadow of the future perspective with nascent research on the flexibility of temporary organizations, and shifting the focus from the level of individual transactions to that of strategic alliance portfolios, we argue that firms may be willing to accept a higher risk of opportunism when there are offsetting gains in strategic flexibility in managing their strategic alliance portfolio. Consequently, we hypothesize that environmental factors that increase the need for strategic flexibility—namely, dynamism and complexity in the environment—are likely to increase the relative share of time-bound alliances in strategic alliance portfolios. Our analysis of longitudinal data on the intertemporal alliance choices of a large sample of small and medium-sized enterprises provides support for this argument. Our findings fill an important gap in theory about time horizons in interfirm relationships and temporary organizations and show the importance of separating planned terminations from duration-based performance measures.
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The finite-signal-to-noise ratio (SNR) diversity-multiplexing trade-off (DMT) of cooperative diversity protocols are investigated in vehicular networks based on cascaded Rayleigh fading. Lower bounds of DMT at finite SNR for orthogonal and non-orthogonal protocols are derived. The results showcase the first look into the achievable DMT trade-off of cooperative diversity in volatile vehicular environments. It is shown that the diversity gains are significantly suboptimal at realistic SNRs.
Resumo:
This study elucidated the shadow price of greenhouse gas (GHG) emissions for 1,024 international companies worldwide that were surveyed from 15 industries in 37 major countries. Our results indicate that the shadow price of GHG at the firm level is much higher than indicated in previous studies. The higher shadow price was found in this study as a result of the use of Scope 3 GHG emissions data. The results of this research indicate that a firm would carry a high cost of GHG emissions if Scope 3 GHG emissions were the focus of the discussion of corporate social responsibility. In addition, such shadow prices were determined to differ substantially among countries, among sectors, and within sectors. Although a number of studies have calculated the shadow price of GHG emissions, these studies have employed country-level or industry-level data or a small sample of firm-level data in one country. This new data from a worldwide firm analysis of the shadow price of GHG emissions can play an important role in developing climate policy and promoting sustainable development.
Resumo:
Clipped was a solo developed from a showing of Stage One Creative Development: Experience Has No Shadow at the Judith Wright Centre for Contemporary Arts in 2010. The solo was choreographed for EDC dancer Elise May as part of EDC Solo Festival 2011. The solo showcased the twisting movement of the dancer, feminine and awkward, sensual and fragile, carving abstract images through the space. In the Courier Mail dance critic Olivia Stewart commented, “Artistic director Natalie Weir and Vanessa Mafe retrospectively gave EDC’s Riannon McLean and Elise May movement that harnessed their power and prowess” (2011, 54) In the The Australian dance critic Shaaron Boughen comments, “May's own performance in Vanessa Mafe's Clipped was mature and sophisticated, showing the breadth of skills that this young artist has developed” (2011, 19)
Resumo:
In this paper conditional hidden Markov model (HMM) filters and conditional Kalman filters (KF) are coupled together to improve demodulation of differential encoded signals in noisy fading channels. We present an indicator matrix representation for differential encoded signals and the optimal HMM filter for demodulation. The filter requires O(N3) calculations per time iteration, where N is the number of message symbols. Decision feedback equalisation is investigated via coupling the optimal HMM filter for estimating the message, conditioned on estimates of the channel parameters, and a KF for estimating the channel states, conditioned on soft information message estimates. The particular differential encoding scheme examined in this paper is differential phase shift keying. However, the techniques developed can be extended to other forms of differential modulation. The channel model we use allows for multiplicative channel distortions and additive white Gaussian noise. Simulation studies are also presented.
Resumo:
[Conclusion] We have explored two dimensions of the Australian OHS statutes which enable statutory OHS duties to reach more than one employer or self-employed person within a corporate group or network. First, most of the OHS statutes contain provisions extending the reach of employer’s duty beyond the employer’s employees. One legislative technique is to deem contractors and their employees to be employees of the principal contractor. Another imposes duties on employers and self-employed persons to persons who are not employees, so that employers and self-employed persons can be responsible for the OHS of firms, and those they engage, lower in the contractual chain. These duties are non-delegable, meaning that the principal contractor cannot seek to delegate OHS duties to firms lower in the contractual chain. Second, new Victorian ‘shadow officer’ provisions can be applied to remove difficulties and doubt as to the liability of partners in a partnership, officers of unincorporated associations, joint venturers, and holding and subsidiary companies within corporate groups. While the provisions can be argued simply to confirm that a partner who fails to take reasonable care in relation to OHS will be guilty of an offence, we demonstrate that there are very real benefits to having ‘shadow officer’ provisions which remove uncertainties about the liability of unincorporated associations, joint ventures and corporate groups. Perhaps most significantly, the Victorian corporate officer provisions have the potential to extend liability to individuals and other entities within organisational structures, where those individuals and entities make or participate in making decisions that affect the whole or a substantial part of the organisation’s business, and are responsible for an OHS offence having been committed, due to their failure to take reasonable care. We suggest that similar provisions should be included in all OHS statutes, to overcome at least some of the barriers limiting group responsibility for OHS statutory duties.
Resumo:
This article examines the new model for corporate officer liability under section 144 of the Occupational Health and Safety Act 2004 (Vic), and explores the extent to which this might effectively extend responsibility for OHS offences to members of corporate groups, such as holding companies. In doing so, the authors canvass the failure of corporate law to impose such obligations on corporate officers in general, and on holding companies as shadow officers. It is argued that provisions such as section 144 of the Victorian Act should be included in all OHS legislation.
Resumo:
An opportunistic relay selection scheme improving cooperative diversity is devised using the concept of a virtual SIMO-MISO antenna array. By incorporating multiple users as a virtual distributed antenna, not only helps combat fading but also provides significant advantage in terms of energy consumption. The proposed efficient multiple relay selection uses the concept of the distributed Alamouti scheme in a time varying environment to realize cooperative networking in wireless relay networks and provides the platform for outage, Diversiy-Multiplexing Tradeoff (DMT) and Bit-Error-Rate (BER) analysis to conclude that it is capable of achieving promising diversity gains by operating at much lower SNR when compared with conventional relay selection methods. It also has the added advantage of conserving energy for the relays that are reachable but not selected for the cooperative communication.
Resumo:
As each day passes, and as new and better devices and services are developed, more and more government and private services are being moved to an online format. This movement makes access to the internet an essential for 21st Century life. The internet has become so integrated in our lives that many of us cannot imagine how we could operate without it. This omnipresent ‘being’ affects all forms of ‘normal’ social and economic activity and does so in ways that we do not realize. Those with access are able to engage with government, business, and family and friends more easily, which can lead to an improved standard of living. For the disadvantaged, however – those with the desire but without the capacity – a lack of access can be socially isolating. "Between the idea And the reality Between the motion And the act Falls the Shadow – T. S. Elliott. “The Hollow Men” Engagement in the internet economy requires both physical access and the individual to have the necessary finances and skills to make and sustain their use. If governments and the international community want a fully functioning internet economy this requires that all individuals must be operating in it. That not all individuals do so means, very simply, that the internet economy is not fully functioning. The text contextualizes for policy makers and legislatures why it is essential to ensure that individuals have appropriate access to the internet and what can be done to achieve it. The interrelationship/overlap between why access is essential, how it can be achieved and the central role of the individual to the internet economy is explored and translated into the concept of connectedness. From this, solutions for ensuring connectedness for all individuals are developed. It is Dr Cradduck’s hope that in the not too distant future readers will puzzle over why texts such as this needed to be written.