Description:
In deep braced excavations, struts and walers play an essential role in the whole supporting system. For multi-level strut systems, accidental strut failure is possible. Once a single strut fails, it is possible for the loads carried from the previous failed strut to be transferred to the adjacent struts and therefore cause one or more struts to fail. Consequently, progressive collapse may occur and cause the whole excavation system to fail. One of the reasons for the Nicoll Highway Collapse was attributed to the failure of the struts and walers. Consequently, for the design of braced excavation systems in Singapore, one of the requirements by the building authorities is to perform one-strut failure analyses, in order to ensure that there is no progressive collapse when one strut was damaged due to a construction accident. Therefore, plane strain 2D and three-dimensional (3D) finite element analyses of one-strut failure of the braced excavation system were carried out in this study to investigate the effects of one-strut failure on the adjacent struts.
Description:
The dynamic stress and electric displacement intensity factors of impermeable cracks in homogeneous piezoelectric materials and interface cracks in piezoelectric bimaterials are evaluated by extending the scaled boundary finite element method (SBFEM). In this method, a piezoelectric plate is divided into polygons. Each polygon is treated as a scaled boundary finite element subdomain. Only the boundaries of the subdomains need to be discretized with line elements. The dynamic properties of a subdomain are represented by the high order stiffness and mass matrices obtained from a continued fraction solution, which is able to represent the high frequency response with only 3-4 terms per wavelength. The semi-analytical solutions model singular stress and electric displacement fields in the vicinity of crack tips accurately and efficiently. The dynamic stress and electric displacement intensity factors are evaluated directly from the scaled boundary finite element solutions. No asymptotic solution, local mesh refinement or other special treatments around a crack tip are required. Numerical examples are presented to verify the proposed technique with the analytical solutions and the results from the literature. The present results highlight the accuracy, simplicity and efficiency of the proposed technique.
Description:
Reachability queries on large directed graphs have attracted much attention recently. The existing work either uses spanning structures, such as chains or trees, to compress the complete transitive closure, or utilizes the 2-hop strategy to describe the reachability. Almost all of these approaches work well for very sparse graphs. However, the challenging problem is that as the ratio of the number of edges to the number of vertices increases, the size of the compressed transitive closure grows very large. In this paper, we propose a new 3-hop indexing scheme for directed graphs with higher density. The basic idea of 3-hop indexing is to use chain structures in combination with hops to minimize the number of structures that must be indexed. Technically, our goal is to find a 3-hop scheme over dense DAGs (directed acyclic graphs) with minimum index size. We develop an efficient algorithm to discover a transitive closure contour, which yields near optimal index size. Empirical studies show that our 3-hop scheme has much smaller index size than state-of-the-art reachability query schemes such as 2-hop and path-tree when DAGs are not very sparse, while our query time is close to path-tree, which is considered to be one of the best reachability query schemes.
Description:
Strengthening reinforced concrete (RC) columns with external confining devices such as FRP wraps or steel tube is widely used in construction. By using external confining devices, both the strength and ductility of RC columns are significantly improved. However, numerical modeling to predict the capacity of strengthened RC columns is limited and often oversimplified. One of the biggest challenges in numerical modeling is to deal with unequal dilation between the concrete inner core (enclosed by both transverse steel and FRP wraps) and the concrete outer core (between the transverse steel and FRP wraps). Inaccurate modeling on the concrete dilatant behavior can lead to incorrect strength prediction. Sophisticated constitutive models which are able to model concrete dilation and robust modeling techniques are required. In this paper, three-dimensional non-linear finite element analysis (3D-NLFEA) of circular RC columns confined with conventional steel stirrups and FRP wraps is presented. In the FEA, the initial stiffness method with Process Modification (acceleration technique) is used to solve the equilibrium forces in the global solution. The constitutive model is based on the plasticity formulation proposed by the authors, which can capture the effective lateral modulus (EL) of the confining devices. This lateral modulus is obtained by observing the principal incremental stresses and strains at each element gauss point. It was found that, the lateral modulus is greatly affected by the boundary condition, dilatant behavior of the constitutive model and the Poisson's ratio of the external confining device. To validate the performance of the proposed model, several comparisons of the proposed model, using 3D-NLFEA, with experimental results is presented. The comparisons show that the predicted response using 3D-NLFEA and the experimental results of RC columns confined with FRP are in a good agreement.
Description:
With the rapid development of computer hardware and software, the application of computer graphics has also got rapid development in all walks of life. Development of graphics has gone through a few decades, and now the computer has already entered a three-dimensional era. The three-dimensional graphics can be seen everywhere in real life. Scientific visualization, computer animation and virtual reality technology have become hot topics in recent years. Researches in the field of computer graphics hierarchy deepen gradually and grow fast. This article describes three common systems of graphics rendering engine, as well as discusses how to use the engine to create a three-dimensional graphics system, and introduces the binding and application of 3D graphics rendering and stage design.
Description:
The large size of raw 3D optical coherence tomography (OCT) volumes poses challenges for deep learning methods as it cannot be accommodated on a single GPU in its original resolution. The direct analysis of these volumes however, provides advantages such as circumventing the need for the segmentation of retinal structures. Previously, a deep learning (DL) approach was proposed for the detection of glaucoma directly from 3D OCT volumes, where the volumes were significantly downsampled first. In this paper, we propose an end-to-end DL model for the detection of glaucoma that doubles the number of input voxels of the previously proposed method, and also boasts an improved AUC = 0.973 over the results obtained using the previously proposed approach of AUC = 0.946. Furthermore, this paper also includes a quantitative analysis of the regions of the volume highlighted by grad-CAM visualization. Occlusion of these highlighted regions resulted in a drop in performance by 40%, indicating that the regions highlighted by gradient-weighted class activation maps (grad-CAM) are indeed crucial to the performance of the model.
Description:
View of the house and garden at 58 Narracan Avenue, Yallourn, which was the residence of the General Superintendent of the State Electricity Commission.
Description:
Copyright: Centre for Gippsland Studies, Federation University Australia.
Description:
View of the house and garden at 58 Narracan Avenue, Yallourn, which was the residence of the General Superintendent of the State Electricity Commission.
Description:
Copyright: Centre for Gippsland Studies, Federation University Australia.
Description:
View of the house and garden at 58 Narracan Avenue, Yallourn, which was the residence of the General Superintendent of the State Electricity Commission.
Description:
Copyright: Centre for Gippsland Studies, Federation University Australia.
Description:
View of the house and garden at 58 Narracan Avenue, Yallourn, which was the residence of the General Superintendent of the State Electricity Commission.
Description:
Copyright: Centre for Gippsland Studies, Federation University Australia.
Description:
View of the house and garden at 58 Narracan Avenue which was the residence of the General Superintendent of the State Electricity Commission.
Description:
Copyright: Centre for Gippsland Studies, Federation University Australia.
Description:
View of the house and garden at 58 Narracan Avenue which was the residence of the General Superintendent of the State Electricity Commission.
Description:
Copyright: Centre for Gippsland Studies, Federation University Australia.
Description:
Women who have a cognitive impairment (CI) (including mental illness, dementia, intellectual disability and acquired brain injury) are particularly vulnerable to sexual assault, yet very few assaults are reported to police. Once reported very few cases find their way through the justice system. The discourse of stereotyping and its impact on access to justice for victim/survivors is central to this research project which examines the uptake and exit stages of reports of sexual assault by persons with a cognitive impairment to police in Victoria, Australia. Data collection involves focus group interviews, analysis of police records of reports of sexual assault by persons with a cognitive impairment across a finite period of time (2002-2004) and one in-depth case study of a victim of rape with a cognitive impairment who successfully accessed the legal system to a completed trial. This paper discusses the results of preliminary analysis of data collected from focus group discussions held across Victoria including rural, regional and metropolitan locations with police, sexual assault counsellors and advocates for sexual assault victims with a CI. Data have been analysed using a modified Grounded Theory framework and ‘interpretative repertoire’ analysis. These methods of analysis have been used to identify commonly held perceptions of sexual assault victims who have cognitive impairments. Early findings indicate that police and advocates alike, draw on commonly held stereotypes about victims with cognitive impairments. These include whether their word can be believed and assumptions that ‘they cannot stand up to the rigors of the justice system’. Potentially these views have a significant effect on the depth and quality of service the victims receive from their advocate as well as the continued pathway of the report through the justice system.
Description:
The Australian Assistance Plan (AAP) was an innovative programme of social welfare reform. Foreshadowed in the late 1960s, launched in 1973, and abolished in 1977, it was the subject of substantial commentary during and immediately after its brief existence. Attracting more brickbats than bouquets, the AAP was variously described as ‘a feasible and indeed exciting approach’, ‘the most random of random experiments’, ‘welfare on the cheap’, ‘a confusing program’ and ‘good news’.2 In contrast to other major initiatives of the Whitlam Labor government, it has attracted almost no scholarly analysis since the 1970s.