Corners-based composite descriptor for shapes

In this paper, a composite descriptor for shape retrieval is proposed. The composite descriptor is obtained based upon corner-points and shape region. In an earlier paper, we proposed a composite descriptor based on shape region and shape contour, however, the descriptor was not effective for all perspective and geometric transformations. Hence, we modify the composite descriptor by replacing contour features with corner-points features. The proposed descriptor is obtained from Generic FourierDescriptors (GFD) of the shape region and the GFD ofthe corner-points. We study the performance of the proposed composite descriptor. The proposed method is evaluated using Item S8 within the MPEG-7 Still Images Content Set. Experimental results show that the proposed descriptor is effective.

Application of the strain localization CAFE model to investigate extrusion with various die shapes

Multi scale CAFE model for the prediction of initiation and propagation of the micro shear bands and shear bands in metallic materials subjected to plastic deformation is presented. The CAFE approach is the combination of the Cellular Automata (CA) and the Finite Element (FE) methods. The application of the developed CAFE model to analyze material flow during extrusion is the objective of the present work. The proposed CAFE approach is applied in this work to simulation of the extrusion with flat face and convex dies and to investigate differences in the material flow. The initial FE meshes with the set of the CA point are generated for the numerical tests and the results of the metal flow predicted by the CAFE method are presented in the paper.

Tax morale in Australia : what shapes it and has it changed over time?

Why taxpayers pay their taxes voluntarily is an important question for tax administrations worldwide. Some believe it is because taxpayers are deterred from tax evasion out of a fear of being caught or penalized. Others, in contrast, suggest that factors such as the level of tax morale one has (ie, the intrinsic motivation one has to pay their tax) affects compliance behaviour. While there have been numerous empirical studies published that have explored the role of deterrence on tax compliance behaviour, very few studies have explored the concept of tax morale in any detail. This article therefore attempts to rectify this gap in the literature. If tax morale is important in determining compliance behaviour, as several researchers have suggested, then it is also important to understand what might affect one’s level of tax morale. The specific aim of this article will be to identify factors that shape or have an impact on tax morale. Using data collected from the Australian waves of the 1981 and 1995 World Values Survey, this study will demonstrate that factors such as trust and moral beliefs plan an important role in shaping tax morale in Australia. Further, it will be shown that tax morale has increased significantly in Australia since the early 1980s, and that it has done so at a faster rate than many other OECD countries. Possible explanations for this increase will be discussed.

Visual narratives in the children's picture story book : an investigation of the extent to which the formal structuring of a visual narrative retrieves a pastiche of past experiences and images which in turn shapes and redirects the story

Throughout this research, the notion that illustrators of children's books embark on two types of activity has been reinforced at every turn. On one hand the artist acknowledges the external world by organising images of actions and events in the contexts of place and time. This process involves bringing ideas into a physical form and demands the structuring of characters, settings, and story development. Planning and decisions are informed by imperatives that recognise the need for conventions of articulation and communication to a particular target audience. These then become a mayor priority of bookmaking and are constantly impacted on by publishers1 demands and ethical constraints. The other perspective sees the illustrator as expresser where the core of visual narratives for children celebrates the potency of imagination. Here dreams, fantasies, memories and the unconscious become the conduits to shaping sequential images. The artist is engaged not simply in visually telling a story, but rather telling facets of his or her own story. This exegesis traces the evolution of my own picture story book Eddie's Fantastic Fortnight published by Five Mile Press Publishers in tandem with the insights and reflections of five of Australia's most prominent illustrators. It examines whether the structure invested in a visual narrative liberates expressive response, ascribing to the premise that bookmaking plays an informing role to imagination. Equally it adopts the alternative position which asserts that the essence of children's books is indeed fantasy, memory and dreams. This proposition views imagination and inspiration as the primary catalyst around which illustrators build their narrative. In the often lengthy processes of bookmaking, these considerations constantly shift. I have attempted to explore and reveal these mobile and ever changing priorities, not only in my own work, but also through leading exponents in the field.

An investigation of complex shapes during low pressure tube hydroforming

Hollow structures made of Advanced High Strength Steel (AHSS) are increasingly used in the automobile industry for crash and structural components. Generally high pressure hydroforming is used to form these tabular parts, which is a costly manufacturing process due to the high pressure equipment and large tonnage presses required. A new process termed low pressure hydroforming, where a pressurized tube is crushed between two dies, represents a more cost effective alternative due to the lower pressures and die closing forces required.

In this study the low pressure tube hydroforming of one simple and two different complex hollow shapes is investigated. The complexities of the pat1S compared to simple shapes are critically studied and the die filling conditions are investigated and discussed. FUl1hennore the thickness distributions over the circumference of the part during forming are analyzed.

Characterising material and process variation effects on springback robustness for a semi-cylindrical sheet metal forming process

Variation in the incoming sheet material and fluctuations in the press setup is unavoidable in many stamping plants. The effect of these variations can have a large influence on the quality of the final stamping, in particular, unpredictable springback of the sheet when the tooling is removed. While stochastic simulation techniques have been developed to simulate this problem, there has been little research that connects the influence of the noise sources to springback. This paper characterises the effect of material and process variation on the robustness of springback for a semi-cylindrical channel forming operation, which shares a similar cross-section profile as many automotive structural components. The study was conducted using the specialised sheet metal forming package AutoForm^TM Sigma, for which a series of stochastic simulations were performed with each of the noise sources incrementally introduced. The effective stress and effective strain scatter in a critical location of the part was examined and a response window, which indicates the respective process robustness, was defined. The incremental introduction of the noise sources allows the change in size of the stressstrain response window to be tracked. The results showed that changes to process variation parameters, such as BHP and friction coefficient, directly affect the strain component of the stressstrain response window by altering the magnitude of external work applied to forming system. Material variation, on the other hand, directly affected the stress component of the response window. A relationship between the effective stressstrain response window and the variation in springback was also established.

Analytical solutions and finite element modelling of deep drawing process for cylindrical metal cups

Analytical modelling of deep drawing process is of value in preliminary process design to illustrate the influence of major variables including friction and strain hardening on punch loads, cup dimensions and process limits. In this study, analytical models including theoretical solution and a series of finite element models are developed to account for the influences of process parameters including friction coefficient, tooling geometry and material properties on deep drawing of metal cups. The accuracy of both the theoretical and finite element solutions is satisfactory compared with those from experimental work.

Swan foraging shapes spatial distribution of two submerged plants, favouring the preferred prey species

Compared to terrestrial environments, grazing intensity on belowground plant parts may be particularly strong in aquatic environments, which may have great effects on plant-community structure. We observed that the submerged macrophyte, Potamogeton pectinatus, which mainly reproduces with tubers, often grows at intermediate water depth and that P. perfoliatus, which mainly reproduces with rhizomes and turions, grows in either shallow or deep water. One mechanism behind this distributional pattern may be that swans prefer to feed on P. pectinatus tubers at intermediate water depths. We hypothesised that when swans feed on tubers in the sediment, P. perfoliatus rhizomes and turions may be damaged by the uprooting, whereas the small round tubers of P. pectinatus that escaped herbivory may be more tolerant to this bioturbation. In spring 2000, we transplanted P. perfoliatus rhizomes into a P. pectinatus stand and followed growth in plots protected and unprotected, respectively, from bird foraging. Although swan foraging reduced tuber biomass in unprotected plots, leading to lower P. pectinatus density in spring 2001, this species grew well both in protected and unprotected plots later that summer. In contrast, swan grazing had a dramatic negative effect on P. perfoliatus that persisted throughout the summer of 2001, with close to no plants in the unprotected plots and high densities in the protected plots. Our results demonstrate that herbivorous waterbirds may play a crucial role in the distribution and prevalence of specific plant species. Furthermore, since their grazing benefitted their preferred food source, the interaction between swans and P. pectinatus may be classified as ecologically mutualistic.

Soft matter : from shapes to forces on the nanoscale

Soft matter deforms in response to imposed external forces. Here we demonstrate how dynamic surface forces are linked to far-field deformations. This offers a new paradigm for determining forces between soft particles in colloidal systems. The particular example we use to illustrate this concept is that of a fluid drop interacting with a solid wall through hydrodynamic drainage flow coupled with repulsive or attractive dissimilar electrical double layer interactions. The force can be deduced from a simple analysis of the drop surface geometry outside the interaction zone.

Amazing shapes : chirality

The use of songs to help learning of content is consistent with multi-sensory models of learning. Here, a song to the tune of “Amazing Grace” can be used in the classroom to enhance the learning of chirality and the Cahn-Ingold-Prelog priority rules.

Direct synthesis, growth mechanism, and optical properties of 3D AlN nanostructures with urchin shapes

Aluminum nitride (AƖN) nanostructures have shown novel physical and chemical properties that are essential for technological applications. We report a vapor-solid growth of novel three-dimensional (3D) A1N urchin-like nanostmcture in DC arc plasma via the direct reaction between Al vapor and N₂ gas without any catalyst or template. The as-prepared 3D A1N nanostructures which have urchin-like shapes consist of numerous microdaggers with sharp tips and lengths of up to several micrometers and widths of 0.5-2 µm. A growth mechanism of A1N nanostructures with urchin shapes was suggested and explained in detail. The optical properties of the AƖN nanostructures with urchin shapes were also studied with photoluminescence spectrum, which reveals a broad emission, suggesting potential applications in electronic and optoelectronic nanodevices.

Sex-dependent selection differentially shapes genetic variation on and off the guppy Y chromosome

Because selection is often sex-dependent, alleles can have positive effects on fitness in one sex and negative effects in the other, resulting in intralocus sexual conflict. Evolutionary theory predicts that intralocus sexual conflict can drive the evolution of sex limitation, sex-linkage, and sex chromosome differentiation. However, evidence that sex-dependent selection results in sex-linkage is limited. Here, we formally partition the contribution of Y-linked and non-Y-linked quantitative genetic variation in coloration, tail, and body size of male guppies (Poecilia reticulata)—traits previously implicated as sexually antagonistic. We show that these traits are strongly genetically correlated, both on and off the Y chromosome, but that these correlations differ in sign and magnitude between both parts of the genome. As predicted, variation in attractiveness was found to be associated with the Y-linked, rather than with the non-Y-linked component of genetic variation in male ornamentation. These findings show how the evolution of Y-linkage may be able to resolve sexual conflict. More generally, they provide unique insight into how sex-specific selection has the potential to differentially shape the genetic architecture of fitness traits across different parts of the genome.