A new perspective of storm bite on sandy beaches using unmanned aerial vehicles

Aerial imagery collected before and after major storm events is ideal for the assessment of coastal landscape change driven by individual high-magnitude events. Using traditional satellite sensors and manned aerial systems can be challenging due to issues related to cloud cover, mobilization expenses and resolution. Rapid advances in unmanned aerial vehicle (UAV) technology allow for the cost-effective collection of aerial imagery and topography at centimetre resolution suitable for assessing change in coastal ecosystems. In this study we demonstrate the utility of UAV-based photogrammetry to quantify storm-driven sediment dynamics on a sandy beach on the open-coast shoreline of Victoria, Australia. UAV-based aerial photography was collected before and after a major storm event. High-resolution (< 5 cm) aerial imagery and digital surface models were acquired and change-detection techniques were applied to quantify changes in the beachface. An average beach erosion of 12.24 m3/m with a maximum of 28.05 m3/m was observed, and the volume of sand cut from the beachface and retreat of the foredune are clearly illustrated. Following the storm event, erosion was estimated at 7259.94 ± 503.69 m3 along 550 m of beach. By combining the aerial imagery and derived topographic datasets we demonstrate the advantage of UAV-based photogrammetry techniques for rapid high-resolution data collection in semi-remote locations. Its utility in setting unlimited virtual vantage points is also illustrated and the valuable perspective it provides for tracking landscape change discussed.

Pup production and population trends of the Australian fur seal (Arctocephalus pusillus doriferus)

We estimated the number of live Australian fur seal pups using capture-markresights, direct ground counts, or aerial photography at all breeding sites following the pupping season of November-December 2002. Pups were recorded at 17 locations; nine previously known colony sites, one newly recognized colony and seven haul-out sites where pups are occasionally born. In order of size, the colonies were Lady Julia Percy Island (5,899 pups), Seal Rocks (4,882), The Skerries (2,486), Judgment Rocks (2,427), Kanowna Island (2,301), Moriarty Rocks (1,007), Reid Rocks (384), West Moncoeur Island (257), and Tenth Island (124). The newly recognized site was Rag Island, in the Cliffy Group, where we recorded 30 pups. We also recorded pups at the following haul-out sites: Cape Bridge-water (7 pups), Bull Rock (7), Wright Rock (5), Twin Islet (1), The Friars (1), He des Phoques (1), and Montague Island (1). In total, we estimate there were 19,819 (SE = 163) live pups at the time of the counts. We discuss trends in pup numbers and derive current population estimates for the Australian fur seal.

Duplicating road patterns in South African informal settlements using procedural techniques

The formation of informal settlements in and around urban complexes has largely been ignored in the context of procedural city modeling. However, many cities in South Africa and globally can attest to the presence of such settlements. This paper analyses the phenomenon of informal settlements from a procedural modeling perspective. Aerial photography from two South African urban complexes, namely Johannesburg and Cape Town is used as a basis for the extraction of various features that distinguish different types of settlements. In particular, the road patterns which have formed within such settlements are analysed, and various procedural techniques proposed (including Voronoi diagrams, subdivision and L-systems) to replicate the identified features. A qualitative assessment of the procedural techniques is provided, and the most suitable combination of techniques identified for unstructured and structured settlements. In particular it is found that a combination of Voronoi diagrams and subdivision provides the closest match to unstructured informal settlements. A combination of L-systems, Voronoi diagrams and subdivision is found to produce the closest pattern to a structured informal settlement.

Yaringa and French Island Marine National Park habitat mapping

Deakin University and the Department of Primary Industries were commissioned by ParksVictoria (PV) to create two updated habitat maps for Yaringa and French Island MarineNational Parks. The team obtained a ground-truth data set using in situ video and still photographs. This dataset was used to develop and assess predictive models of benthic marine habitat distributions incorporating data from World-View-2 imagery atmospherically corrected by CSIRO and LiDAR (Light Detection and Ranging) bathymetry. In addition, the team applied an unsupervised classification approach to an aerial photograph to assess the differences between the two remote sensors. This report describes the results of the mapping as well as the methodology used to produce these habitat maps.This study has provided mapping of intertidal and subtidal habitats of Yaringa and FrenchIsland MNPs at a 2 m resolution with fair to good accuracies (Kappa 0.40-0.75). These were combined with mangrove and saltmarsh habitats recently mapped by Boon et al. (2011) to provide compete-coverage habitat maps of Yaringa and French Island MNPs.The mapping showed that Yaringa MNP was dominated by mangroves, wet saltmarsh and dense Zostereaceae, covering 33%, 29% and 19%, respectively. Similarly, intertidalvegetation and subtidal vegetation (dominated by Zosteraceae) covered 26% and 25% ofFrench Island MNP. However, as a result of turbidity and missing satellite imagery 27% ofFrench Island MNP remains unmapped.The coupling of WV-2 and LiDAR reduced potential artefacts (e.g. sun glint causing whiteand black pixels known as the “salt and pepper effect”). The satellite classification appeared to provide better results than the aerial photography classification. However, since there is a two-year difference between the capture of the aerial photography and the collection of the ground-truth data this comparison is potentially temporally confounded. It must also be noted that there are differences in costs of the data,the spatial resolution between the two datasets (i.e. WV-2 = 2 m and the Aerial = 0.5 m) and the amount spectral information contained in the data (i.e. WV-2 = 8 bands and the aerial = 4 bands), which may ultimately determine its utility for a particular project.The spatial assessment using FRAGSTATs of habitat patches within Yaringa MNP provides a viable and cost effect way to assess habitat condition (i.e. shape, size and arrangement).This spatial assessment determined that dense Zosteraceae and NVSG habitat classeswere generally larger in patch size and continuity than the medium/sparse Zosteraceaehabitat. The application spatial techniques to time-series mapping may provide a way toremotely monitor the change in the spatial characteristics of marine habitats.This work was successful in providing new baseline habitat maps using a repeatable method meaning that any future changes in intertidal and shallow water marine habitats may be assessed in a consistent way with quantitative error assessments. In wider use, these maps should also allow improved conservation planning, fisheries and catchment management, and contribute toward infrastructure planning to limit impacts on Western Port.

An obligate beach bird selects sub-, inter- and supra-tidal habitat elements

Few habitat models are available for widespread, obligate, high-energy sandy shore vertebrates, such as the Eastern Hooded Plover Thinornis cucullatus cucullatus. We examined habitat attributes which determined the difference between sites where plovers breed and randomly-selected absence sites (determined from long-term systematic monitoring). A variety of habitat variables were derived from aerial photography and bathymetric and terrestrial Light Detection And Ranging (LiDAR) data. Logistic regression against eight candidate variables, in a model selection framework, revealed considerable support for four variables with respect to explaining the presence of breeding territories. In particular, the amount of unvegetated dune and foredune which was unvegetated, and the amount of intertidal and sub-tidal reef were positively associated with the presence of breeding territories. Thus, plovers apparently select certain habitat in which to breed, involving sub-tidal, intertidal and supra-tidal habitat elements. The model also helps explain the virtual absence of breeding plovers from long sections of superficially suitable habitat, such as the fourth longest continuous beach in the world.

Photography and christian mission: George Brown`s images of the New Britain mission 1875-80

In 1875, Methodist George Brown arrived in the Bismarck Archipelago to establish the New Britain Mission. Based in the Duke of York Islands, Brown's territory covered New Ireland and the Gazelle Peninsula of New Britain. The mission was one of the first to be photographed from its inception. The Australian Museum holds 96 plates from the first five years of the mission. Brown's photographs are a visual record of conditions and peoples of the time. Analysed in relation to Brown's writings they are indicative of the relationships and bonds established through photography both in the mission field and across wider scientific and church audiences. The methodology employed here also challenges the kinds of interpretations of photographs that can arise from visual analyses relying solely on the caption and the posing of the subject.

The rough sets feature selection for trees recognition in color aerial images using genetic algorithms

Selecting a set of features which is optimal for a given task is the problem which plays an important role in a wide variety of contexts including pattern recognition, images understanding and machine learning. The concept of reduction of the decision table based on the rough set is very useful for feature selection. In this paper, a genetic algorithm based approach is presented to search the relative reduct decision table of the rough set. This approach has the ability to accommodate multiple criteria such as accuracy and cost of classification into the feature selection process and finds the effective feature subset for texture classification . On the basis of the effective feature subset selected, this paper presents a method to extract the objects which are higher than their surroundings, such as trees or forest, in the color aerial images. The experiments results show that the feature subset selected and the method of the object extraction presented in this paper are practical and effective.

Memory, photography, and the politics of abuse : the ambiguous nature of photography

Critical commentary on Australian artist Bill Henson’s work including the series Untitled 1994-1995 which represented Australia at the Venice Biennale is frequently framed within the discourse of the ‘white cube’. Its contextualisation in predominantly art historical and formalist perspectives tends to operate as a mechanism that denies affective and embodied dimensions of meaning making. Much the same could be said of the work of Marian Drew who uses road kill in her photographic still life works. However, the ‘distancing’ in these works is also achieved through historical allusion, which at the same time reactivates the fl ow of emotional empathy and desire. In this paper, I ask the question: “What distinguishes the work of these two artists with media images of torture?”

My attempt to address this question will involve a narrative re-reading of selected works of Henson and Drew incorporating notions of affect, identification, memory and desire as processes which operate non-discursively, but which are inseparable from memory and lived experiences. This will permit a double exposure of the work of these artists. Within a psychoanalytical context, my re-reading will be used to extend an understanding of the now familiar press and Internet images of the torture of Iraqi prisoners.

As a metaphor for desire and ideology, photography operates within manifest and latent registers. I will argue that certain forms of photographic practice may be understood in terms of a politics of abuse — instantiating an uneven differentiation of power between actants, the winning (forcefully or otherwise) of consent or complicity, the silencing of refusal of resistance and/or the incriminating of the ‘victim’ — whilst at the same time upholding the claim of verisimilitude and aesthetic or ethical intent. Critical engagement with such practices is crucial to an understanding of the relationship between institutional discourses, trauma and abuse in contemporary society.

Neck muscle activation and head postures in common high performance aerial combat maneuvers

Introduction: Neck injuries are common in high performance combat pilots and have been attributed to high gravitational forces and the non-neutral head postures adopted during aerial combat maneuvers. There is still little known about the pathomechanics of these injuries.

Methods: Six Royal Australian Air Force Hawk pilots flew a sortie that included combinations of three +Gz levels (1, 3, and 5) and four head postures (Neutral, Turn, Extension, and Check-6). Surface electromyography from neck and shoulder muscles was recorded in flight. Three-dimensional measures of head postures adopted in flight were estimated postflight with respect to end-range of the cervical spine using an electromagnetic tracking device.

Results: Mean muscle activation increased significantly with both increasing +Gz and non-neutral head postures. Check-6 at +5 Gz (mean activation of all muscles = 51% MVIC) elicited significantly greater muscle activation in most muscles when compared with Neutral, Extension, and Turn head postures. High levels of muscle co-contraction were evident in high acceleration and non-neutral head postures. Head kinematics showed Check-6 was closest to end-range in any movement plane (86% ROM in rotation) and produced the greatest magnitude of rotation in other planes. Turn and Extension showed a large magnitude of rotation with reference to end-range in the primary plane of motion but displayed smaller rotations in other planes.

Discussion: High levels of neck muscle activation and co-contraction due to high +Gz and head postures close to end range were evident in this study, suggesting the major influence of these factors on the pathomechanics of neck injuries in high performance combat pilots.

Neck exercises compared to muscle activation during aerial combat maneuvers

Introduction: Performing specific neck strengthening exercises has been proposed to decrease the incidence of neck injury and pain in high performance combat pilots. However, there is little known about these exercises in comparison to the demands on the neck musculature in flight.

Methods: Eight male non-pilots performed specific neck exercises using two different modalities (elastic band and resistance machine) at six different intensities in flexion, extension, and lateral bending. Six Royal Australian Air Force Hawk pilots flew a sortie that included combinations of three +Gz levels and four head positions. Surface electromyography (EMG) from selected neck and shoulder muscles was recorded in both activities.

Results: Muscle activation levels recorded during the three elastic band exercises were similar to in-flight EMG collected at +1 Gz (15% MVIC). EMG levels elicited during the 50% resistance machine exercises were between the +3 Gz (9-40% MVIC) and +5 Gz (16-53% MVIC) ranges of muscle activations in most muscles. EMG recorded during 70% and 90% resistance machine exercises were generally higher than in-flight EMG at +5 Gz.

Discussion: Elastic band exercises could possibly be useful to pilots who fly low +Gz missions while 50% resistance machine mimicked neck loads experienced by combat pilots flying high +Gz ACM. The 70% and 90% resistance machine intensities are known to optimize maximal strength but should be administered with care because of the unknown spinal loads and diminished muscle force generating capacity after exercise.

Changing preferences : conventional photography to digital imaging in communicating architecture

Architectural photography is merging into a new form of image capture and output which is a mix of conventional photography and digital imagery. As this transition takes place it is anticipated that the credibility of the image may also change. the aim of the project is to research the perception of the quality, content and authenticity of both conventional photography and digitally produced images used within the architectural profession.