1,767,980 research outputs found
Beach and cliff retreat induced by storm groups at Forte Novo,Algarve (Portugal)
No full textLittoral cell dynamics may change through time as a reaction to modifications of the coastal system. Along the Vilamoura-Quarteira coastline, the construction of a groin field limited the sediment supply to the already narrow Forte Novo beach, located downdrift, enhanced wave action on the cliff base and lead to long-term persistent cliff retreat. This research uses a set of surveys from November 2009 to March 2010 to determine short-term soft cliff erosion associated to storm groups at this sediment starved area. Following the initial LiDAR survey, three subsequent surveys were performed using a reflectorless total station for monitoring the cliff face, and RTK-DGPS to monitor the position of the cliff top, the cliff foot and the topography of the adjacent beach. Results indicate an important reduction in beach levels during successive storms (without significant beach recovery in between), allowing waves to further attack the cliff base and contributing to further enhance the structural and permanent cliff retreat. This work demonstrates how a combination of magnitude and frequency of extreme events coupled with development of the coastline, has led to increased cliff-beach recession and to the permanent dislocation of the cliff face
Microseismic monitoring of the controls on coastal rock cliff erosion
No full textThe aim of this thesis has been to improve understanding of the controls on coastal rock cliff erosion, utilising microseismic ground motion. Coastal cliff erosion has remained poorly understood, in part confounded by the challenges associated with monitoring changes to and controls upon steep slopes in the coastal zone. As a result the relative contribution of marine to subaerial and episodic to iterative forcing is based upon models with only limited field validation. For two years, from July 2008 to July 2010, cliff top microseismic ground motions were monitored using a broadband seismometer, installed on top of a 70 m high hard rock cliff of Jurassic mudstone, shale and sandstone, on the North York Moors National Park coast, UK. Concurrently cliff face erosion was monitored using high-resolution 3D terrestrial laser scanning. Regional-scale marine and weather data for the monitoring period and modelled nearshore wave conditions were used to establish the conditions under which cliff microseismic ground motions were generated. Distinct ground motion frequency bands were found to correlate with a range of marine and subaerial processes that transfer energy to the coastline and cliff. Fundamentally, microseismic sources were identified both at the cliff face from, for example, direct wave impact during cliff toe inundation, but also at more distal locations resulting from the transfer of energy from gravity and infragravity waves. Further analysis demonstrates statistically significant correlations between rockfall and cliff ground motion generated by wave impacts and wind at the cliff face, but also surprisingly waves across the nearshore and offshore, implying direct environmental controls on cliff erosion rate. The significance of longer period ground motion, representative of ocean gravity and infragravity waves also identifies an almost constant dynamic loading of the cliff rock mass, highlighting a potential for progressive deterioration of the cliff rock. The analysis demonstrates that cliff top microseismic ground motion provides a valuable proxy for marine and atmospheric forcing at coastal cliffs, overcoming the limitations in quantifying and testing controls on cliff erosion. The findings of this study are used to develop a new conceptual model of the environmental processes and failure mechanisms that control rock cliff erosion
Cliff Taylor
No full text"Sgt Cliff Taylor NX106025 19th Hvy A.A. Bty (A.I.F.) Fannie Bay Jan 1943 - Nov 1944".Sergeant Cliff Taylor NX106025 19th Heavy Anti Aircraft Battery (Australian Imperial Forces) Fannie Bay January 1943 - November 1944
Modelling failure mechanisms of soft cliff profiles
No full textA large proportion of the 11,000 km coastline of the United Kingdom is backed by soft cliffs. These cliffs are subject to frequent slumping and landslip events, particularly where sea and ground water percolates into the soil and rock. Many of these cliffs are formed from glaciogenic sediments, which experience severe erosion and rapid recession with long-term horizontal recession rates typically up to 2-3 m/year. A series of scaled physical model tests have been conducted using a large centrifuge facility with two-dimensional cliff models. These were tested in a wave flume container located on the centrifuge. Wave loading was created using a quasi-flap paddle system that was located at the opposite end of the centrifuge box. A number of tests were conducted using different cliff materials (i.e. combinations of sand and Portland cement). A parametric study was carried out to assess the influence of variations in cliff geometry and height, soil properties, wave amplitude and period. From these tests, it has been found that generally, failures occurred by progressive undercutting of the cliff toe, followed by global failure of the cliff mass
Neuroethology, Computational
No full textOver the past decade, a number of neural network researchers have used the term computational neuroethology to describe a specific approach to neuroethology. Neuroethology is the study of the neural mechanisms underlying the generation of behavior in animals, and hence it lies at the intersection of neuroscience (the study of nervous systems) and ethology (the study of animal behavior); for an introduction to neuroethology, see Simmons and Young (1999). The definition of computational neuroethology is very similar, but is not quite so dependent on studying animals: animals just happen to be biological autonomous agents. But there are also non-biological autonomous agents such as some types of robots, and some types of simulated embodied agents operating in virtual worlds. In this context, autonomous agents are self-governing entities capable of operating (i.e., coordinating perception and action) for extended periods of time in environments that are complex, uncertain, and dynamic. Thus, computational neuroethology can be characterised as the attempt to analyze the computational principles underlying the generation of behavior in animals and in artificial autonomous agents
Portrait of William Dargie, of Melbourne, Victoria, 1953 [picture] /
No full textCondition: Good, but has two punch holes and is glued to card.; Title from caption on reverse.; Part of a collection of three photographs of William Dargie, two of which show him painting.; "L.30134, William Alexander Dargie, Australian artist. William Alexander Dargie, of Melbourne, Victoria, one of Australia's leading artists ... Australian official photograph by Cliff Bottomley." --Printed on label on reverse
Portrait of William Dargie, Australian artist, 1953 [picture] /
No full textCondition: Good, but has two punch holes and is glued to card.; Title from caption on reverse.; Part of a collection of three photographs of William Dargie, two of which show him painting.; "L.30133, William Alexander Dargie, Australian artist. William Alexander Dargie, of Melbourne, Victoria, one of Australia's leading artists ... Australian official photograph by Cliff Bottomley." --Printed on label on reverse
Portrait of William Dargie, noted Australian artist, putting the finishing touches to a large mural, 1954 [picture] /
No full textCondition: Good, but has two punch holes and is glued to card.; Title from caption on reverse.; Part of a collection of three photographs of William Dargie, two of which show him painting.; "William Alexander Dargie, noted Australian artist, putting the finsihing touches to a large mural that decorates the interior of a modern agricultural implement factory in Dandenong Road, Dandenong, Victoria. Australian official photograph by Cliff Bottomley, L30452." --Printed on label on reverse
Cliff Peterson
No full text"Gnr Cliff Peterson SX 30621 Fenton 1081 A.A."Index to the location of names on the quilt ; H-J2Gunner Cliff Peterson. SX 30621 Fenton 1081 Anti Aircraft.These patches were signed by people who visited the Northern Territory during the Year of Commemoration of the Bombing of Darwin, 1992, or who wrote from interstate or overseas during that year. The quilt measures almost five metres by three, and is designed to resemble a typical porcellanite stone wall as can still be seen on some old Darwin buildings. In addition to the names on the Quilt there are nurse's colourpatch, the emblem of the Civil Construction Corps and twenty pictures of sites which would have been familiar to people of Darwin at the time. Some of the buildings can still be seen today, whereas others have disappeared as a result of enemy action, Cyclone Tracy or the indomitable march of progress. The illustrations on the Quilt were based on photographs taken during the war years and now held in the collections of the Northern Territory Library. The Quilt was made by Jenny Armour, and took about 18 months of weekends and other free time to complete, using techniques of patchwork, applique, and machine embroidery and was quilted using 100% Australian wool batting
ZIP60: Further Explorations in the Evolutionary Design of Trader Agents and Online Auction-Market Mechanisms
No full textThe “ZIP” adaptive automated trading algorithm has been demonstrated to outperform human traders in experimental studies of continuous double auction (CDA) markets populated by mixtures of human and “software robot” traders. Previous papers have shown that values of the eight parameters governing behavior of ZIP traders can be automatically optimized using a genetic algorithm (GA), and that markets populated by GA-optimized traders perform better than those populated by ZIP traders with manually-set parameter values. This paper introduces a more sophisticated version of the ZIP algorithm, called “ZIP60”, which requires the values of 60 parameters to be set correctly. ZIP60 is shown here to produce significantly better results in comparison to the original ZIP algorithm (called “ZIP8” hereafter) when a GA is used to search the 60-dimensional parameter space. It is also demonstrated here that this works best when the GA itself has control over the dimensionality of the search-space, allowing evolution to guide the expansion of the search-space up from 8 parameters to 60 via intermediate steps. Principal component analysis of the best evolved ZIP60 parameter-sets establishes that no ZIP8 solutions are embedded in the 60-dimensional space. Moreover, some of the results and analysis presented here cast doubt on previously-published ZIP8 results concerning the evolution of new ‘hybrid’ auction mechanisms that appeared to be improvements on the CDA: it now seems likely that those results were actually consequences of the relative lack of sophistication in the original ZIP8 algorithm, because “hybrid” mechanisms occur much less frequently when ZIP60s are used
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