Abolhasan, M & Wright, A 2008, 'Survey of the potential of emerging wireless technologies to improve telecommunication services in remote Australian settlements', RANGELAND JOURNAL, vol. 30, no. 1, pp. 157-165.
View/Download from: Publisher's site
View description>>
Providing efficient yet cost effective telecommunication systems to Aboriginal people living in remote locations has proven to be a challenging task. This is primarily due to low population density and distance from major service centres. Extending high-capacity telecommunications infrastructure to these people would incur high costs of installation, maintenance and administration without significant financial returns. The cost of services such as cabled phone lines to all houses, satellite and wireless cellular networks are often unaffordable for people in remote settlements, and, as a result, the provision of telecommunication services is often subsidised by the government. New wireless standards and products are being developed which could provide broadband-type network connections to large areas at an affordable price. This paper describes these new standards and products and their potential applications in rural and remote regions. There is also a comparison of their transmission requirements, cost, performance and coverage with several currently available technologies.
Blumenstein, M 2008, 'Cursive Character Segmentation Using Neural Network Techniques', Studies in Computational Intelligence, vol. 90, pp. 259-275.
View/Download from: Publisher's site
View description>>
The segmentation of cursive and mixed scripts persists to be a difficult problem in the area of handwriting recognition. This research details advances for segmenting characters in off-line cursive script. Specifically, a heuristic algorithm and a neural network-based technique, which uses a structural feature vector representation, are proposed and combined for identifying incorrect segmentation points. Following the location of appropriate anchorage points, a character extraction technique, using segmentation paths, is employed to complete the segmentation process. Results are presented for neural-based heuristic segmentation, segmentation point validation, character recognition, segmentation path detection and overall segmentation accuracy. © 2008 Springer-Verlag Berlin Heidelberg.
Blumenstein, M, Green, S, Fogelman, S, Nguyen, A & Muthukkumarasarny, V 2008, 'Performance analysis of GAME: A generic automated marking environment', COMPUTERS & EDUCATION, vol. 50, no. 4, pp. 1203-1216.
View/Download from: Publisher's site
View description>>
This paper describes the Generic Automated Marking Environment (GAME) and provides a detailed analysis of its performance in assessing student programming projects and exercises. GAME has been designed to automatically assess programming assignments written in a variety of languages based on the "structure" of the source code and the correctness of the program's output. Currently, the system is able to mark programs written in Java, C++ and the C language. To use the system, instructors are required to provide a simple "marking schema" for each given assessment item, which includes pertinent information such as the location of files and the model solution. In this research, GAME has been tested on a number of student programming exercises and assignments and its performance has been compared against that of a human marker. An in-depth statistical analysis of the comparison is presented, providing encouraging results and directions for employing GAME as a tool for teaching and learning. © 2006 Elsevier Ltd. All rights reserved.
Cha, D, Blumenstein, M, Zhang, H & Jeng, D-S 2008, 'A Neural-Genetic Technique for Coastal Engineering: Determining Wave-induced Seabed Liquefaction Depth', Studies in Computational Intelligence, vol. 82, pp. 337-351.
View/Download from: Publisher's site
View description>>
In the past decade, computational intelligence (CI) techniques have been widely adopted in various fields such as business, science and engineering, as well as information technology. Specifically, hybrid techniques using artificial neural networks (ANNs) and genetic algorithms (GAs) are becoming an important alternative for solving problems in the field of engineering in comparison to traditional solutions, which ordinarily use complicated mathematical theories. The wave-induced seabed liquefaction problem is one of the most critical issues for analysing and designing marine structures such as caissons, oil platforms and harbours. In the past, various investigations into wave-induced seabed liquefaction have been carried out including numerical models, analytical solutions and some laboratory experiments. However, most previous numerical studies are based on solving complicated partial differential equations. In this study, the proposed neural-genetic model is applied to wave-induced liquefaction, which provides a better prediction of liquefaction potential. The neural-genetic simulation results illustrate the applicability of the hybrid technique for the accurate prediction of wave-induced liquefaction depth, which can also provide coastal engineers with alternative tools to analyse the stability of marine sediments. © 2008 Springer-Verlag Berlin Heidelberg.
Choudhury, D & Nimbalkar, SS 2008, 'Seismic Rotational Displacement of Gravity Walls by Pseudodynamic Method', International Journal of Geomechanics, vol. 8, no. 3, pp. 169-175.
View/Download from: Publisher's site
Choudhury, D, Bharti, RK, Chauhan, S & Indraratna, B 2008, 'Response of Multilayer Foundation System beneath Railway Track under Cyclic Loading', Journal of Geotechnical and Geoenvironmental Engineering, vol. 134, no. 10, pp. 1558-1563.
View/Download from: Publisher's site
Gao, W, Zhang, N, Ji, JC & Du, HP 2008, 'Dynamic analysis of vehicles with uncertainty', PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART D-JOURNAL OF AUTOMOBILE ENGINEERING, vol. 222, no. D5, pp. 657-664.
View/Download from: Publisher's site
View description>>
The probabilistic and interval dynamic analysis of cars with uncertain parameters under random road input excitations by using a two-degree-of-freedom car model are presented in this paper. In the probabilistic analytical model, the vehicle parameters, including the sprung mass, unsprung mass, suspension damping, suspension, and tyre stiffness, are considered as random variables. The mean value, standard deviation, and variation coefficient of the vehicle's natural frequencies and mode shapes are obtained by using the Monte Carlo simulation method. Then, the computational expressions for the numerical characteristics of the mean square value of the vehicle's random response in the frequency domain are developed by means of the random variable's functional moment method. Considering the vehicle parameters as interval variables, the lower bound, upper bound, and interval change ratio value of the vehicle's random responses are obtained by means of the interval operations. The influences of the uncertainty of the vehicle parameters on the vehicle's natural frequencies, mode shapes, and dynamic responses are investigated in detail using a practical example. The comparison of the vehicle's dynamic characteristics using the probabilistic and interval analysis are also demonstrated. © IMechE 2008.
Gens, A & Sheng, D 2008, 'Special issue on “Unsaturated soils: Models, algorithms and applications”', Computers and Geotechnics, vol. 35, no. 6, pp. 809-809.
View/Download from: Publisher's site
Ha, QP, Kwok, NM, Nguyen, MT, Li, J & Samali, B 2008, 'Mitigation of seismic responses on building structures using MR dampers with Lyapunov-based control', STRUCTURAL CONTROL & HEALTH MONITORING, vol. 15, no. 4, pp. 604-621.
View/Download from: Publisher's site
View description>>
As losses of human lives and damages to buildings frequently occur during earthquake periods, it is crucial to mitigate structural vibrations. This paper describes the development of a Lyapunov-based control approach for magnetorheological (MR) dampers integrated in building structures to suppress quake-induced vibrations. In this work, MR dampers are used as semi-active devices, taking the advantages of the fail-safe operation and low power consumption. The control of MR dampers is, however, hindered by their hysteretic force-velocity responses and usually leads to indirect strategies compromising controllability and performance. To enhance the system performance, a Lyapunov-based controller is proposed here for direct control of the supply currents to the dampers for a multi-storey building. The dampers are configured in a differential mode to counteract the force-offset problem from the use of a single damper. The effectiveness of the proposed technique is verified, in simulations, by using a building model subject to quake-like excitations. Copyright © 2007 John Wiley & Sons, Ltd.
Indraratna, B 2008, 'Recent advancements in the use of prefabricated vertical drains in soft soils', Australian Geomechanics Journal, vol. 43, no. 1, pp. 29-46.
View description>>
A system of prefabricated vertical drains with surcharge load to accelerate consolidation by shortening the drainage path is one of the most popular methods of soft ground improvement. An analytical solution is proposed based on radial (lateral) soil permeability while considering variations in vacuum pressure. The predicted smear zone and effects of drain unsaturation are compared with laboratory data obtained from large-scale radial consolidation tests. When a higher load is required to meet the desired rate of settlement and the cost of raising a surcharge embankment is also significant, the application of vacuum pressure with a reduced surcharge load can be used. In this method, the vacuum creates a suction head that increases the effective stress. Analytical and numerical analyses were conducted for several case histories using the equivalent plane strain solution for Darcian and non-Darcian flows. The effectiveness of vertical drains on cyclic loading was also investigated based on a laboratory study. . This paper shows that vertical drains can dissipate the built up excess pore pressure under repeated loading and that short drains can be sufficient in certain cases rather than driving the drains to cover the entire depth of soft clay deposits. The research findings verify that the effects of soil disturbance and vacuum pressure can affect soil consolidation considerably, which means that these aspects need to be modelled correctly in any numerical approaches.
Indraratna, B, Aljorany, A & Rujikiatkamjorn, C 2008, 'Analytical and Numerical Modeling of Consolidation by Vertical Drain beneath a Circular Embankment', International Journal of Geomechanics, vol. 8, no. 3, pp. 199-206.
View/Download from: Publisher's site
Indraratna, B, Jayanathan, M & Brown, ET 2008, 'Shear strength model for overconsolidated clay-infilled idealised rock joints', Géotechnique, vol. 58, no. 1, pp. 55-65.
View/Download from: Publisher's site
View description>>
Saturated infilled joints can contribute to the instability of rock masses during undrained shearing. This paper reports an experimental investigation into the effect of the overconsolidation of infilled rough joints on undrained shear behaviour. A revised model is presented for predicting the shear strength of rough infilled joints on the basis of experimental tests carried out on idealised sawtoothed joints with natural silty clay as the infill material. Tests were conducted under consolidated undrained conditions in a high-pressure triaxial apparatus on joints having a dip angle of 60°. Pore pressure development in the infill materials was monitored. The results show that the effect of asperities on shear strength is significant up to a critical asperity height to infill thickness ratio (t/a), whereas the shear behaviour is controlled by the infill alone beyond this critical value. The proposed model for predicting the shear strength of rough infilled joints describes how the OCR influences the shear strength, pore water pressure development, and critical t/a ratio.
Indraratna, B, Muttuvel, T, Khabbaz, H & Armstrong, R 2008, 'Predicting the Erosion Rate of Chemically Treated Soil Using a Process Simulation Apparatus for Internal Crack Erosion', Journal of Geotechnical and Geoenvironmental Engineering, vol. 134, no. 6, pp. 837-844.
View/Download from: Publisher's site
View description>>
Chemical stabilization is an effective ground improvement technique for controlling erosion. Two stabilizers, lignosulfonate and cement, were used to study how effectively they could stabilize erodible silty sand collected from Wombeyan Caves, NSW, Australia. To conduct this research, four dosages of cement 0.5, 1, 1.5, and 2% and four dosages of lignosulfonate 0.1, 0.2, 0.4, and 0.6% by dry weight of soil were selected. All treated and untreated soil specimens were compacted to 90 and 95% of their maximum dry density to study the effect of compaction level on erodibility. The erosion characteristics of treated and untreated soil samples were investigated using a process simulation apparatus for internal crack erosion designed and built at the University of Wollongong. The findings of this study indicated that both chemical stabilizers increased the resistance to erosion because of their cementing properties. It was also found that the critical shear stress increased linearly with the amount of stabilizer, and the coefficient of soil erosion decreased as a power function of the critical shear stress.
Indraratna, B, Muttuvel, T, Khabbaz, H & Armstrong, R 2008, 'Predicting the erosion rate of chemically treated soil using a process simulation apparatus for internal crack erosion', JOURNAL OF GEOTECHNICAL AND GEOENVIRONMENTAL ENGINEERING, vol. 134, no. 6, pp. 837-844.
View/Download from: Publisher's site
View description>>
Chemical stabilization is an effective ground improvement technique for controlling erosion. Two stabilizers, lignosulfonate and cement, were used to study how effectively they could stabilize erodible silty sand collected from Wombeyan Caves, NSW, Australia. To conduct this research, four dosages of cement (0.5, 1, 1.5, and 2%) and four dosages of lignosulfonate (0.1, 0.2, 0.4, and 0.6%) by dry weight of soil were selected. All treated and untreated soil specimens were compacted to 90 and 95% of their maximum dry density to study the effect of compaction level on erodibility. The erosion characteristics of treated and untreated soil samples were investigated using a process simulation apparatus for internal crack erosion designed and built at the University of Wollongong. The findings of this study indicated that both chemical stabilizers increased the resistance to erosion because of their cementing properties. It was also found that the critical shear stress increased linearly with the amount of stabilizer, and the coefficient of soil erosion decreased as a power function of the critical shear stress. © 2008 ASCE.
Indraratna, B, Trani, LDO & Khabbaz, H 2008, 'A critical review on granular dam filter behaviour – from particle sizes to constriction-based design criteria', Geomechanics and Geoengineering, vol. 3, no. 4, pp. 279-290.
View/Download from: Publisher's site
View description>>
Over emphasis on tests results involving base soils with increasing coefficient of uniformity (Cu) makes the reliability of an empirical particle-based criterion for effective filters questionable. Extra measures such as regrading of base soil are then necessary in order to capture the effectiveness of filter constriction sizes in trapping eroding fines. Recent studies which focused on the role of the sizes of filter voids on overall filtration behaviour have deployed constriction size approaches that were shown to be equally acceptable methods for distinguishing between effective and ineffective filters. This paper examines the evolution of this approach, starting from past empirical and mathematical investigations and proceeding to the eventual development of geometric-probabilistic methods with special reference to embankment dams. Models based on dominant and controlling constriction sizes are introduced, and subsequently the constriction-based retention criteria for granular filters are presented. The proposed retention criteria were verified based on extensive experimental data taken from small- and large-scale filtration tests carried out by various authors. The integration of filter compaction, porosity and Cu, together with the incorporation of analytical principles, provides alternative and rigorous design approaches that remove most limitations of the conventional particle-based criteria, thus making the models essentially more comprehensive and quantifiable.
Ji, JC & Zhang, N 2008, 'Additive resonances of a controlled van der Pol-Duffing oscillator', JOURNAL OF SOUND AND VIBRATION, vol. 315, no. 1-2, pp. 22-33.
View/Download from: Publisher's site
View description>>
The trivial equilibrium of a controlled van der Pol-Duffing oscillator with nonlinear feedback control may lose its stability via a non-resonant interaction of two Hopf bifurcations when two critical time delays corresponding to two Hopf bifurcations have the same value. Such an interaction results in a non-resonant bifurcation of co-dimension two. In the vicinity of the non-resonant Hopf bifurcations, the presence of a periodic excitation in the controlled oscillator can induce three types of additive resonances in the forced response, when the frequency of the external excitation and the frequencies of the two Hopf bifurcations satisfy a certain relationship. With the aid of centre manifold theorem and the method of multiple scales, three types of additive resonance responses of the controlled system are investigated by studying the possible solutions and their stability of the four-dimensional ordinary differential equations on the centre manifold. The amplitudes of the free-oscillation terms are found to admit three solutions; two non-trivial solutions and the trivial solution. Of two non-trivial solutions, one is stable and the trivial solution is unstable. A stable non-trivial solution corresponds to a quasi-periodic motion of the original system. It is also found that the frequency-response curves for three cases of additive resonances are an isolated closed curve. It is shown that the forced response of the oscillator may exhibit quasi-periodic motions on a three-dimensional torus consisting of three frequencies; the frequencies of two bifurcating solutions and the frequency of the excitation. Illustrative examples are given to show the quasi-periodic motions. © 2008 Elsevier Ltd. All rights reserved.
Ji, JC, Hansen, CH & Zander, AC 2008, 'Nonlinear Dynamics of Magnetic Bearing Systems', JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND STRUCTURES, vol. 19, no. 12, pp. 1471-1491.
View/Download from: Publisher's site
View description>>
Magnetic bearings use magnetic forces to support various machine components. Because of the non-contact nature of this type of suspension, magnetic bearing technology offers a number of significant advantages over conventional bearings, such as rolling element and fluid film bearings. An active magnetic bearing basically consists of an electromagnetic actuator, position sensors, power amplifiers, and a feedback controller. All of these components are characterized by nonlinear behavior and therefore the entire system is inherently nonlinear. However, in simulations of the dynamic behavior of magnetic bearing systems, the nonlinearities are usually neglected to simplify the analysis and only linear models are used. Moreover, many control techniques currently used in magnetic bearing systems are generally designed by ignoring nonlinear effects. The main reason for simplification is the intractability of the complexity of the actual model. In fact, the inherent nonlinear properties of magnetic bearing systems can lead to dynamic behavior of a magnetically suspended rotor that is distinctly different from that predicted using a simple linearized model. Therefore, the nonlinearities should be taken into account. This literature review is focused on the nonlinear dynamics of magnetic bearing systems and it provides background information on analytical methods, nonlinear vibrations resulting from a rotor contacting auxiliary bearings, and other active topics of research involving the nonlinear properties of magnetic bearing systems, such as nonlinear self-sensing magnetic bearings and nonlinear control of magnetic bearings. The review concludes with a brief discussion on current and possible future directions for research on the nonlinear dynamics of magnetic bearing systems. © 2008 SAGE Publications.
Lee, J, Sanmugarasa, K, Blumenstein, M & Loo, Y-C 2008, 'Improving the reliability of a Bridge Management System (BMS) using an ANN-based Backward Prediction Model (BPM)', Automation in Construction, vol. 17, no. 6, pp. 758-772.
View/Download from: Publisher's site
View description>>
The slow adoption of Bridge Management Systems (BMSs) and its impractical future prediction of the condition rating of bridges are attributed to the inconsistency between BMS inputs and bridge agencies' existing data for a BMS in terms of compatibility and the enormous number of bridge datasets that include historical structural information. Among these, historical bridge element condition ratings are some of the key pieces of information required for bridge asset prioritisation but in most cases only limited data is available. This study addresses the abovementioned difficulties faced by bridge management agencies by using limited historical bridge inspection records to model time-series element-level data. This paper presents an Artificial Neural Network (ANN) based prediction model, called the Backward Prediction Model (BPM), for generating historical bridge condition ratings using limited bridge inspection records. The BPM employs historical non-bridge datasets such as traffic volumes, populations and climates, to establish correlations with existing bridge condition ratings from very limited bridge inspection records. The resulting model predicts the missing historical condition ratings of individual bridge elements. The outcome of this study can contribute to reducing the uncertainty in predicting future bridge condition ratings and so improve the reliability of various BMS analysis outcomes. © 2008 Elsevier B.V. All rights reserved.
Lee, S 2008, 'Utilization of optical remote sensing data and geographic information system tools for regional landslide hazard analysis by using binomial logistic regression model', Journal of Applied Remote Sensing, vol. 2, no. 1, pp. 023542-023542.
View/Download from: Publisher's site
Li, X, Duan, Q, Han, X & Sheng, DC 2008, 'Adaptive coupled arbitrary Lagrangian–Eulerian finite element and meshfree method for injection molding process', International Journal for Numerical Methods in Engineering, vol. 73, no. 8, pp. 1153-1180.
View/Download from: Publisher's site
View description>>
AbstractThis paper presents an adaptive method that couples the finite element (FE) method and the meshfree (MF) method in the arbitrary Lagrangian–Eulerian (ALE) description for numerical simulation of injection molding processes. The ALE feature is used to accurately capture moving free surfaces of flow problems and, meanwhile, to alleviate mesh distortion and its influence on the accuracy and robustness of numerical solutions. Based on the continuous blending method, originally presented for properly imposing the essential boundaryconditions in MF methods, the coupled ALE FE and MF method is developed, to exploit the respective advantages of both FE and MF methods, but to avoid their respective weak points. The method features self‐adaptivity in view of the fact that moving free surfaces in an injection molding process are continuously advanced. The Pressure‐stabilized Fractional Step Algorithm, in which the modified version of the finite increment calculus process is extended to the coupled ALE FE and MF method, is used to solve incompressible Navier–Stokes equations governing the injected polymer flow, so that equal low‐orderu−p interpolations that violate the LBB condition can be effectively used. Numerical experiments demonstrate the significance and ability of the proposed method for numerical simulation of injection molding processes. Copyright © 2007 John Wiley & Sons, Ltd.
Nazem, M, Sheng, D, Carter, JP & Sloan, SW 2008, 'Arbitrary Lagrangian–Eulerian method for large‐strain consolidation problems', International Journal for Numerical and Analytical Methods in Geomechanics, vol. 32, no. 9, pp. 1023-1050.
View/Download from: Publisher's site
View description>>
AbstractIn this paper, an arbitrary Lagrangian–Eulerian (ALE) method is generalized to solve consolidation problems involving large deformation. Special issues such as pore‐water pressure convection, permeability and void ratio updates due to rotation and convection, mesh refinement and equilibrium checks are discussed. A simple and effective mesh refinement scheme is presented for the ALE method. The ALE method as well as an updated‐Lagrangian method is then used to solve some classical consolidation problems involving large deformations with different constitutive laws. The results clearly show the advantage and efficiency of the ALE method for these examples. Copyright © 2007 John Wiley & Sons, Ltd.
NIMBALKAR, SS & CHOUDHURY, D 2008, 'EFFECTS OF BODY WAVES AND SOIL AMPLIFICATION ON SEISMIC EARTH PRESSURES', Journal of Earthquake and Tsunami, vol. 02, no. 01, pp. 33-52.
View/Download from: Publisher's site
View description>>
To design a retaining wall, conventional Mononobe–Okabe method, which is based on the pseudo-static approach and gives the linear distribution of seismic earth pressures in an approximate way, is used to compute the seismic earth pressures. In this paper, pseudo-dynamic approach is used to compute the seismic earth pressures on a rigid retaining wall by considering the effects of time, phase difference in shear and primary waves and soil amplification along with the horizontal and vertical seismic accelerations and other soil properties. Design value of the seismic active earth pressure coefficient is found to increase with increase in the seismic accelerations, phase difference in body waves and soil amplification, whereas the reverse trend is observed for the passive case. Influence of various soil parameters on seismic passive earth pressure is more significant than that for the active case under harmonic seismic loading. Results are provided in the combined tabular and graphical non-dimensional form for both the seismic active and passive earth pressures. Present results are compared with the available results in literature to validate the proposed non-linearity of seismic earth pressure distribution.
Pedroso, DM, Sheng, D & Sloan, SW 2008, 'Stress update algorithm for elastoplastic models with nonconvex yield surfaces', International Journal for Numerical Methods in Engineering, vol. 76, no. 13, pp. 2029-2062.
View/Download from: Publisher's site
View description>>
AbstractA stress update algorithm for elastoplastic models with nonconvex yield surfaces is presented. An explicit algorithm based on the Runge–Kutta embedded method of second‐order accuracy is developed. The crossing of the yield surface is properly taken into account by means of a robust intersection‐finding algorithm. This algorithm is based on a simple multiple‐root‐finding technique, which requires the yield function, evaluated along a given secant stress path, to be continuously differentiable to the second order. The accuracy of the intersection‐finding algorithm is illustrated through examples using simple yield functions similar to the ones adopted in models for unsaturated soils and the modified Cam clay model yield surface with a nonconvex Argyris et al. failure criterion. Isoerror surfaces and finite element simulations are used to investigate the accuracy and efficiency of the stress update algorithm. It is observed that although the algorithm for nonconvex surfaces is slower than its equivalent for convex surfaces, the accuracy can be controlled locally by means of specified tolerances. Copyright © 2008 John Wiley & Sons, Ltd.
Pradhan, B 2008, 'Lee S (2008a) Utilization of optical remote sensing data and GIS tools for regional landslide hazard analysis by using an artificial neural network model at Selangor', Malaysia Earth Sci Front, vol. 14, no. 6, pp. 143-152.
Pradhan, B, Lee, S, Mansor, S, Buchroithner, MF, Jallaluddin, N & Khujaimah, Z 2008, 'Utilization of optical remote sensing data and geographic information system tools for regional landslide hazard analysis by using binomial logistic regression model', J Appl Remote Sens, vol. 2, no. 1, pp. 1-11.
Rajapakse, JC, Yang Wang, Xuebin Zheng & Juan Zhou 2008, 'Probabilistic Framework for Brain Connectivity From Functional MR Images', IEEE Transactions on Medical Imaging, vol. 27, no. 6, pp. 825-833.
View/Download from: Publisher's site
Rankine, BR, Indraratna, B, Sivakugan, N, Wijeyakulasuriya, V & Rujikiatkamjorn, C 2008, 'Foundation behaviour below an embankment on soft soils', Proceedings of the Institution of Civil Engineers - Geotechnical Engineering, vol. 161, no. 5, pp. 259-267.
View/Download from: Publisher's site
View description>>
The Sunshine Motorway is one of the major traffic corridors that service the South East region of Queensland, Australia. Initial investigations for the construction of pavements in area 2, stage 2 of the motorway began in late 1990. Large areas of soft, highly compressible organic clays were found to exist over the length of the upgrade. Also, because the topography of the proposed alignment was mostly low lying, earthworks were required over a large portion of the route. Prior to any earthworks for the stage being undertaken, a trial embankment was constructed in the area to provide an understanding of the foundation behaviour and to also ensure the overall success of the project. The finite difference code FLAC was employed to investigate the performance of the full-scale trial embankment, and the underlying soft clay. Predictions of the excess pore pressure and both vertical and lateral displacements are made and compared with field observations.
Raut, AK & Indraratna, B 2008, 'Further Advancement in Filtration Criteria through Constriction-Based Techniques', Journal of Geotechnical and Geoenvironmental Engineering, vol. 134, no. 6, pp. 883-887.
View/Download from: Publisher's site
Rujikiatkamjorn, C, Indraratna, B & Chu, J 2008, '2D and 3D Numerical Modeling of Combined Surcharge and Vacuum Preloading with Vertical Drains', International Journal of Geomechanics, vol. 8, no. 2, pp. 144-156.
View/Download from: Publisher's site
Samali, B, Dowling, DM & Li, J 2008, 'Dynamic Testing and Analysis of Adobe-Mudbrick Structures', Australian Journal of Structural Engineering, vol. 8, no. 1, pp. 63-75.
View/Download from: Publisher's site
View description>>
Traditional, unreinforced adobe-mudbrick houses are highly susceptible to damage and destruction during seismic events. Research at the University of Technology Sydney has included shake table testing of 10 scale model (1:2) u-shaped adobe wall units to assess the performance of different reinforcement systems and evaluate the response to out-of-plane seismic forces. This paper describes the qualitative and quantitative performance of one unreinforced and two reinforced adobe structures. Results confirm the importance of using appropriately time-scaled input spectra to ensure dynamic similitude and induce damaging near-resonance conditions. The testing and analysis revealed both internally and externally reinforced structures to be effective at impeding initial cracking, as well as delaying major structural damage and ultimate collapse. The system incorporating external vertical reinforcement performed significantly better and has the clear advantage of being simpler to construct, as well as being a viable option for the retrofit-strengthening of existing dwellings. © Institution of Engineers Australia, 2008.
Samali, B, Dowling, DM & Li, J 2008, 'Static and Dynamic Testing of Adobe-Mudbrick Structures', Australian Journal of Structural Engineering, vol. 8, no. 2, pp. 159-170.
View/Download from: Publisher's site
Sathananthan, I, Indraratna, B & Rujikiatkamjorn, C 2008, 'Evaluation of Smear Zone Extent Surrounding Mandrel Driven Vertical Drains Using the Cavity Expansion Theory', International Journal of Geomechanics, vol. 8, no. 6, pp. 355-365.
View/Download from: Publisher's site
Sheng, D, Fredlund, DG & Gens, A 2008, 'A new modelling approach for unsaturated soils using independent stress variables', Canadian Geotechnical Journal, vol. 45, no. 4, pp. 511-534.
View/Download from: Publisher's site
View description>>
Although a number of constitutive models for unsaturated soils exist in the literature, some fundamental questions have not been fully answered. There are questions related to (i) the change of the yield stress with soil suction, (ii) modelling slurry soils, and (iii) the smooth transition between saturated and unsaturated soil states. This paper addresses these questions by proposing an alternative modelling approach. The paper first presents a volumetric model for unsaturated soils. This volumetric model is then used to derive the yield surface in the suction – mean stress space. Hysteresis associated with soil-water characteristic curves is then formulated in the same framework of elastoplasticity. It is shown that volume collapse during wetting and plastic shrinkage during initial drying are both direct results of a suction-dependent hardening law. The proposed model seems to be more flexible in modelling different types of unsaturated soils than most models in the literature. The model can be applied to soils that are dried or loaded from initially slurry conditions, for soils that have low to high air-entry values, and for compacted soils as well.
Sheng, D, Fredlund, DG & Gens, A 2008, 'Reply to the discussion by Zhang and Lytton on “A new modelling approach for unsaturated soils using independent stress variables”Appears in Canadian Geotechnical Journal,45(12): 1784–1787.', Canadian Geotechnical Journal, vol. 45, no. 12, pp. 1788-1794.
View/Download from: Publisher's site
Sheng, D, Gens, A, Fredlund, DG & Sloan, SW 2008, 'Unsaturated soils: From constitutive modelling to numerical algorithms', Computers and Geotechnics, vol. 35, no. 6, pp. 810-824.
View/Download from: Publisher's site
Sheng, D, Pedroso, DM & Abbo, AJ 2008, 'Non-convexity and stress-path dependency of unsaturated soil models', Computational Mechanics, vol. 42, no. 5, pp. 685-694.
View/Download from: Publisher's site
Sheng, D, Pedroso, DM & Abbo, AJ 2008, 'Non-convexity and stress-path dependency of unsaturated soil models', Computational Mechanics, vol. 42, no. 5, pp. 695-695.
View/Download from: Publisher's site
Sheng, D, Yamamoto, H & Wriggers, P 2008, 'Finite Element Analysis of Enlarged End Piles Using Frictional Contact', Soils and Foundations, vol. 48, no. 1, pp. 1-14.
View/Download from: Publisher's site
Sheng, D, Yao, Y & Carter, JP 2008, 'A volume–stress model for sands under isotropic and critical stress states', Canadian Geotechnical Journal, vol. 45, no. 11, pp. 1639-1645.
View/Download from: Publisher's site
View description>>
A simple volume–stress model for granular soils under isotropic and critical stress states is presented. The model is formulated in the double logarithmic space of void ratio versus mean stress. It has the same number of parameters as used in the Cam Clay models to describe isotropic compression, with one additional parameter to define the critical state curve. The model can qualitatively describe a number of unique features of sand behaviour. Comparison with experimental data indicates that the model is able to predict well the volume change of a range of different sands subjected to isotropic and triaxial compression.
Sun, D, Sheng, D, Xiang, L & Sloan, SW 2008, 'Elastoplastic prediction of hydro-mechanical behaviour of unsaturated soils under undrained conditions', Computers and Geotechnics, vol. 35, no. 6, pp. 845-852.
View/Download from: Publisher's site
Abolhasan, M, Hagelstein, B, Wang, JC-P, Franklin, DR, Safaei, F & Wysocki, T 1970, 'Development and Performance Evaluation of a Flexible, Low Cost MANET', ICSPCS: 2ND INTERNATIONAL CONFERENCE ON SIGNAL PROCESSING AND COMMUNICATION SYSTEMS, PROCEEDINGS, 2nd International Conference on Signal Processing and Communication Systems, IEEE, Gold Coast, AUSTRALIA, pp. 107-112.
Abolhasan, M, Hagelstein, B, Wang, JC-P, Franklin, DR, Safaei, F & Wysocki, T 1970, 'Development and performance evaluation of a flexible, low cost MANET', 2008 2nd International Conference on Signal Processing and Communication Systems, 2008 2nd International Conference on Signal Processing and Communication Systems (ICSPCS 2008), IEEE, Gold coast, Australia, pp. 1-6.
View/Download from: Publisher's site
View description>>
Performance evaluations of multi-hop ad hoc network routing protocols have been primarily conducted through analytic and simulation-based studies, which frequently fail to accurately predict real-world performance and behaviour. One reason for this is the challenge in developing low cost, representative test beds with the degree of flexibility and mobility required. We have developed a portable wireless ad hoc node (PWAN) device which establishes multi-hop routes using the OLSR routing protocol. The PWAN's performance has been investigated using two test bed configurations to evaluate its capacity under conditions of high node density in a short-range, multi-hop environment. Our results illustrate that such networks are capable of providing high quality connections when traffic density is low. However, the network link quality deteriorates dramatically as the traffic level increases, and the network topology becomes unstable until the traffic level is reduced.
Aboura, K, Samali, B, Crews, K & Li, J 1970, 'Stochastic Deterioration Processes for Bridge Lifetime Assessment', 2008 Third International Conference on Broadband Communications, Information Technology & Biomedical Applications, 2008 Third International Conference on Broadband Communications, Information Technology & Biomedical Applications, IEEE, Pretoria, South Africa, pp. 437-442.
View/Download from: Publisher's site
View description>>
The Markov chain model can be found in the maintenance and repair problems since the early 60's, is introduced to the maintenance of road infrastructure in the 1980's, and is made to drive the current bridge maintenance optimization systems. While this model results into solvable programming problems and provides a solution, there are a number of criticisms associated with it. In this article, we highlight the shortfalls of the Markov model for bridge infrastructure lifetime assessment and promote the use of stochastic processes. We use examples from a study for the modeling of the condition of bridges that considers more than 15 years of data. We argue for the applicability of the gamma process and other stochastic processes. © 2008 IEEE.
Aboura, K, Samali, B, Crews, K & Li, J 1970, 'Stochastic processes for modelling bridge deterioration', Futures in Mechanics of Structures and Materials - Proceedings of the 20th Australasian Conference on the Mechanics of Structures and Materials, ACMSM20, Australasian Conference on the Mechanics of Structures and Materials, Taylor and Francis Group, Toowoomba, pp. 533-538.
View description>>
Traditionally, bridge management systems were designed using Markov chain models. Recently, researchers applied the gamma process successfully to structural deterioration problems. The stochastic process captures the temporal variability of degradation, and has been applied to a range of problems in structures. We report on a study for the modelling of the condition of bridges in the state of NSW. The study encompasses large amounts of data spanning more than 15 years. We argue for the applicability of the gamma process and other stochastic processes. While the gamma process has been adopted in the past decade on grounds of mathematical tractability and physical motivation, we also observe another distribution for the deterioration at different times. The finding promotes the stochastic process modelling direction taken in the past decade and brings forth new models for the time-dependent reliability analysis of bridges. © 2009 Taylor & Francis Group, London.
Aoki, Y, Sri Ravindrarajah, R & Khabbaz, H 1970, 'Environmentally friendly sustainable pervious concrete', Futures in Mechanics of Structures and Materials - Proceedings of the 20th Australasian Conference on the Mechanics of Structures and Materials, ACMSM20, Australasian Conference on the Mechanics of Structures and Materials, Taylor & Francis Group, Toowoomba, Queensland, Australia, pp. 567-570.
View description>>
Portland cement is considered as one of the environmentally unfriendly materials due to its contribution to the increased liberation of carbon dioxide to the environment during production. In addition to its impervious nature, when it is used for pavement application, it contributes to increased stormwater runoff to drainage systems, over-burdening the infrastructure and causing excessive flooding in built-up areas. This paper presents the results of an experimental investigation associated with quantifying the properties of pervious concrete containing fly ash, up to 50% as partial replacement for cement. The main goal of this research is to promote the utilisation of fly ash for developing durable and sustainable pervious concrete, which creates less negative environmental impacts. © 2009 Taylor & Francis Group, London.
Choi, F, Li, J, Samali, B & Crews, KI 1970, 'Non Destructive Testing of a Timber Beam using Vibration-Based Approach', The 9th International Conference on Motion and Vibration Control, Technique Universaetet, Munich.
Choi, F, Li, J, Samali, B & Crews, KI 1970, 'Overview of Dynamic Based Damage Detection for Timber Bridges', On-Site Assessment of Concrete, Masonry and Timber Structures - Volume 2, On Site Assessment of Concrete, Masonry and Timber Structures, RILEM Publications, Varena, Italy, pp. 1125-1135.
View description>>
Asset management of bridges throughout the world faces increasing challenges as a result of aging infrastructure and inadequate funding. Replacement of an old bridge is neither viable nor sustainable in many circumstances. As a consequence, there is an urgent need to develop and utilise state-of-the-art techniques to assess and evaluate the 'health state' of existing bridges and to be able to understand and quantify the effects ofdegradation in regard to public safety. This paper presents an overview of experimental work for a project in developing and implementing several dynamic methods for evaluation of damage in timber bridges. The technique of detecting damage involved the use of modal strain energy commonly referred to in the literature as damage index methods. The project started with simple beams subjected to single and multiple damage and then was extended to a scale timber bridge constructed under laboratory conditions. It was found that after modification on the damage index method, it was well suited to detect single and multiple damage scenarios for a one-dimensional beam. For the laboratory bridge, the damage index method developed for plate-like structures was successful in detecting single and multiple damage with an acceptable degree of accuracy.
Dackermann, U, Li, J & Samali, B 1970, 'Structural damage identification utilising PCA-compressed frequency response functions and neural network ensembles', Futures in Mechanics of Structures and Materials - Proceedings of the 20th Australasian Conference on the Mechanics of Structures and Materials, ACMSM20, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Taylor & Francis Group, Toowoomba, pp. 803-809.
View description>>
This paper presents a damage detection method that utilises FRF data to identify damage in beam structures. The proposed method uses artificial neural networks (ANNs) to map changes in FRFs to damage characteristics. To obtain suitable patterns for ANN inputs, the size of the FRFs is reduced adopting Principal Component Analysis (PCA) techniques. A hierarchy of neural network ensembles is created to take advantage of individual differences from sensor signals. To simulate field applications, the time history data are polluted with white Gaussian noise. The method involves finite element modelling of undamaged and damaged steel beams. By performing transient analysis with the numerical beams, the time histories are obtained and subsequently polluted with different levels of white Gaussian noise. FRFs are determined and compressed utilising PCA techniques. The PCA-reduced FRFs are then used as input patterns for training and testing of neural network ensembles giving the characteristics of the damage. © 2009 Taylor & Francis Group, London.
Fatahi, B, Indraratna, B & Khabbaz, H 1970, 'Numerical and Experimental Study of Tree Influence on the Ground', GeoCongress 2008, GeoCongress 2008, American Society of Civil Engineers, New Orleans, USA, pp. 694-701.
View/Download from: Publisher's site
View description>>
A mathematical model for the rate of root water uptake has been developed considering ground conditions, type of vegetation and climatic parameters. The three independent features in the root water uptake model incorporated in detail are soil suction, root distribution, and potential transpiration. A two dimensional finite element approach has been employed to solve the transient coupled flow and deformation equations in vicinity of a tree. To validate the model, an array of field measurements and the data have been compared with the numerical predictions. The predicted results acquired from the numerical analysis have been compared favourably with the field and the associated laboratory measurements, justifying the assumptions upon which the model has been developed. Copyright ASCE 2008.
Fatahi, B, Khabbaz, H & Indraratna, B 1970, 'Analysis of Matric Suction Effects Induced by Tree Roots on Rail Track Subgrade', Conference Proceedings: CORE2008 Conference on Railway Engineering, Conference on Railway Engineering, RTSA, Perth, WA, Australia, pp. 599-610.
View description>>
This study investigates the eflects of vegetation on soil matric suction and ground deformation. This paper highlights the inter-related parameters contributing to the development of a conceptual evapo-transpiration and root water uptake equilibrium model that is then incorporated in a comprehensive numerical model. The developed numerical model based on the finite element analysis (ABAQUS) considers fully coupled flowdeformation behaviour of soil. The model formulation is based on the effective stress approach developed for unsaturated soils. Based on the proposed model, the distribution of the matric suction proflle adjacent to the tree has been numerically anaiysed. To validate the model, an array of field measurements conducted at Miram site in Victoria, Australia have been compared with the numerical predictions. Then behaviour of a single tree on improving soil behaviour underneath rail tracks has been described. II is found that root water uptake and associated matric suction stabilise the soft soil beneath railway lines and a pattern of trees grown systematically along rail corridors may olter a cost eltective and environmentally attractive solution for the soft ground improvement in the long-term.
Gens, A, Do Guimarães, LN, Śanchez, M & Sheng, D 1970, 'Developments in modelling the generalised behaviour of unsaturated soils', Unsaturated Soils: Advances in Geo-Engineering - Proceedings of the 1st European Conference on Unsaturated Soils, E-UNSAT 2008, 1st European Conference on Unsaturated Soils, CRC PRESS-TAYLOR & FRANCIS GROUP, Durham, ENGLAND, pp. 53-61.
View description>>
A number of developments for the description of the generalised behaviour of unsaturated soils are presented. They can be considered as extensions of the conventional elastoplastic models developed in recent years to simulate the stress-strain behaviour of this type of soils. The following topics are addressed: the consideration of coupled hydraulic models in a thermodynamical framework, the introduction of structural components in the modelling of expansive soil behaviour and the incorporation of temperature and chemical effects. © 2008 Taylor & Francis Group, London.
Getian Ye, Yang Wang, Jie Xu, Gunawan Herman & Bang Zhang 1970, 'A practical approach to multiple super-resolution sprite generation', 2008 IEEE 10th Workshop on Multimedia Signal Processing, 2008 IEEE 10th Workshop on Multimedia Signal Processing (MMSP), IEEE, pp. 70-75.
View/Download from: Publisher's site
View description>>
The MPEG-4 video coding standard introduces a novel concept of sprite or mosaic that is a large image composed of pixels belonging to a video object visible throughout a video segment. The sprite captures spatio-temporal information in a very compact way and makes it possible for efficient object-based video compression. In this paper, we propose a practical approach to generating multiple super-resolution sprites for sprite coding. In order to construct super-resolution sprites and reduce coding cost, we firstly partition a video sequence into multiple independent sprites and group the images covering a similar scene into the same sprite. We then propose efficient and practical algorithms for cumulative global motion estimation and super-resolution sprite construction. Experiments with real video sequences show that the proposed approach outperforms the previous single sprite and multiple sprite techniques. © 2008 IEEE.
Indraratna, B & Khabbaz, H 1970, 'Geotechnical aspects of ballasted rail tracks and stabilising underlying soft soil formation', ADVANCES IN TRANSPORTATION GEOTECHNICS, 1st International Conference on Transportation Geotechnics, CRC PRESS-TAYLOR & FRANCIS GROUP, Nottingham, ENGLAND, pp. 593-599.
Indraratna, B & Rujikiatkamjorn, C 1970, 'Effects of Partially Penetrating Prefabricated Vertical Drains and Loading Patterns on Vacuum Consolidation', GeoCongress 2008, GeoCongress 2008, American Society of Civil Engineers, pp. 596-603.
View/Download from: Publisher's site
View description>>
In this study, numerical modeling of a multi-drain system is employed to determine the optimum penetration depth of prefabricated vertical drains (PVDs) and the vacuum pressure that provides the maximum consolidation settlement and less lateral displacements. The plane strain analysis using an equivalent permeability with transformed unit cell geometry was considered for varying drain length and vacuum load. The effects of the vertical drain length and vacuum pressure on soft clay consolidation were examined through time for 90% degree of consolidation, associated settlement and lateral displacement. Copyright ASCE 2008.
Indraratna, B, Khabbaz, H & Fatahi, B 1970, 'Conceptual development and numerical modelling of vegetation induced suction and implications on rail track stabilisation', 12th International Conference on Computer Methods and Advances in Geomechanics 2008, International Conference of International Association for Computer Methods and Advances in Geomechanics, Indian Institute of Technology, Bombay, Goa, India, pp. 4335-4344.
View description>>
The effects of tree roots on soil suction and ground settlement are investigated. This paper highlights the inter-related parameters contributing to the development of a conceptual evapo-transpiration and root water uptake equilibrium model that is then incorporated in a comprehensive numerical model. The developed numerical model based on the finite element analysis (ABAQUS) considers fully coupled flow-deformation behaviour of soil. Field measurements obtained by the authors from a field site in western Victoria and from past literature are used to validate the model. The predicted results show acceptable agreement with the field data in spite of the assumptions made for simplifying the effects of soil heterogeneity and anisotropy. The numerical analysis proves that the proposed root water uptake model can reliably predict the region of maximum matric suction away from the tree axis. The paper also compares the natural favourable effect of tree roots with the stabilising mechanisms of geosynthetic vertical drains subjected to vacuum pressure. Although this analogy is only justified for shallow vertical drains, the comparison still emphasises the obvious economical advantages of native vegetation.
Indraratna, B, Muttuvel, T & Khabbaz, H 1970, 'Investigating Erosional Behaviour of Chemically Stabilised Erodible Soils', GeoCongress 2008, GeoCongress 2008, American Society of Civil Engineers, New Orleans, Louisiana, USA, pp. 670-677.
View/Download from: Publisher's site
View description>>
Chemical stabilisation is a popular technique to improve the erosion resistance of soils. In this study, two chemical stabilisers, namely lignosulfonate and general purpose Portland cement were tested on two different soils, a silty sand and dispersive clay. A series of erosion tests were performed to study the effectiveness of the stabilisation on increasing the erosion resistance. Results showed that an increase in the critical shear stress of the silty sand with only 0.6% lignosulfonate treatment was equivalent to that with around 2.5% cement treatment. However, the stabilisation of the dispersive clay with 0.6% cement was more effective than 0.6% lignosulfonate. The findings of this research also indicated that the coefficient of soil erosion decreased as a power function of the critical shear stress. Copyright ASCE 2008.
Indraratna, B, Oliveira, D & Mylvaganam, J 1970, 'Revised Shear Strength Model for Soil-Infilled Rock Joints Considering Over-Consolidation Effect', Proceedings of the First Southern Hemisphere International Rock Mechanics Symposium, First Southern Hemisphere International Rock Mechanics Symposium, Australian Centre for Geomechanics, Perth.
View/Download from: Publisher's site
Lee, J, Guan, H, Blumenstein, M & Loo, Y-C 1970, 'An ANN-Based Backward Prediction Model for Reliable Bridge Management System Implementations Using Limited Inspection Records – Case Studies', IABSE Congress, Chicago 2008: Creating and Renewing Urban Structures – Tall Buildings, Bridges and Infrastructure, IABSE Congress, Chicago 2008: Creating and Renewing Urban Structures – Tall Buildings, Bridges and Infrastructure, International Association for Bridge and Structural Engineering (IABSE).
View/Download from: Publisher's site
View description>>
<p>Computer-aided Bridge Management Systems (BMSs) as Decision Support Systems (DSSs) for an effective bridge asset management are used to establish the feasible bridge maintenance, repair and rehabilitation (MR&R) strategies which ensure an adequate level of safety at the lowest possible bridge life-cycle cost. To achieve this goal, keeping up-to-date bridge condition ratings are crucial for a BMS software package. Although most bridge agencies in the past have conducted inspections and maintenance, the form of such bridge inspection records is dissimilar to those required by BMSs. These data inconsistencies inevitably slow down the BMS implementations. This paper presents an Artificial Neural Network (ANN) based prediction model, called the Backward Prediction Model (BPM), for generating unavailable years of historical bridge condition ratings using very limited existing inspection records. The BPM employed historical non-bridge datasets such as traffic volumes, populations and climates, to establish correlations with the existing bridge condition ratings from the very limited bridge inspection records. Such correlations can help fill the condition rating gaps required for an effective and accurate BMS implementation. This paper covers a brief description of the BPM methodology and presents nine case studies. The outcome of this study can help establish a comprehensive condition rating database, which will in turn assist to predict reliable future bridge depreciations.</p>
Lee, J, Loo, Y-C, Guan, H & Blumenstein, M 1970, 'Effective Implementation of a Bridge Management System Using Limited Historical Inspection Records', IABSE Conference, Helsinki 2008: Information and Communication Technology (ICT) for Bridges, Buildings and Construction Practice, IABSE Conference, Helsinki 2008: Information and Communication Technology (ICT) for Bridges, Buildings and Construction Practice, International Association for Bridge and Structural Engineering (IABSE).
View/Download from: Publisher's site
Li, J, Ma, G & Yu, M 1970, 'Penetration analysis for geo-material based on unified strength criterion', International Journal of Impact Engineering, Elsevier BV, pp. 1154-1163.
View/Download from: Publisher's site
Li, J, Samali, B & Xu, YL 1970, 'A new modal based damage detection approach utilising added mass', Futures in Mechanics of Structures and Materials - Proceedings of the 20th Australasian Conference on the Mechanics of Structures and Materials, ACMSM20, Australasian Conference on the Mechanics of Structures and Materials, CRC Press Taylor and Francis Group, Toowoomba, Australia, pp. 789-793.
View description>>
To reliably detect structural damage and estimate damage severity at its early stage poses a great challenge to engineering community. Despite a great deal of research and development in the areas of damage detection and health monitoring, there are very few successful applications in real life damage detection in engineering practices. One of the main obstacles for successful application of damage detection algorithms to real life civil infrastructure is the complex nature of structures and the uncertainties associated with modelling and measurement. This paper presents a new modal based damage detection approach aiming to provide an effective means to improve reliability and accuracy of damage detection. The proposed approach requires measurement data from two states of the structure, i.e. data from the structure 'as-is' and data from the structure after adding a known mass. By means of experimental modal analysis (EMA), the modal parameters of the structure with and without added mass can be obtained. With modal parameters of the said two states and the known added mass, the proposed method will be able to produce the 'in-service' system stiffness matrix. With the element connectivity being known a priori (or assumed reasonably), the 'in-service' element stiffness can be obtained. Location of damage as well as damage severity of the structure will therefore be known. Experimental verification of the proposed method was carried out using a three storey shear building model. The experimental results show that the proposed damage detection method is superior in both damage localisation and damage severity estimation. © 2009 Taylor & Francis Group, London.
Li, Y, Li, J, Samali, B & Wang, J 1970, 'Theoretical and experimental studies on semi-active smart pin joint', Futures in Mechanics of Structures and Materials - Proceedings of the 20th Australasian Conference on the Mechanics of Structures and Materials, ACMSM20, Australasian Conference on the Mechanics of Structures and Materials, Taylor & Francis Group, Toowoomba, Queensland, Australia, pp. 723-728.
View description>>
An intelligent structural system equipped with smart structural members that are controllable in real-time is one effective solution to prevent structural damage and failure during hostile dynamic loadings, thereby leading to effective protection of structures and their occupants. The primary purpose of this study is to design, fabricate and characterise a prototype smart member, namely a semi-active magnetorheological (MR) pin joint, through theoretical modelling and experimental investigation. Design of prototype smart pin joints includes theoretical analysis relating to the rotary plate radius, the property of MR fluids and the gap between the rotary plate and the casing based on the requirements of the dynamics of MR pin joints. It is verified that an MR pin joint with a diameter of 180 mm can produce a torque of up to 30 Nm, which is deemed adequate for realisation of the semi-active control for multi-storey building models in the next stage of research. © 2009 Taylor & Francis Group, London.
Nimbalkar, SS & Choudhury, D 1970, 'Computation of point of application of seismic passive resistance by pseudo-dynamic method', 12th International Conference on Computer Methods and Advances in Geomechanics 2008, pp. 2636-2643.
View description>>
Computation of seismic passive resistance and its point of application is an important aspect of seismic design of retaining wall. Several researchers in the past had obtained seismic passive earth pressures by using the conventional pseudo-static method. In this pseudo-static method, peak ground acceleration is assumed as constant and seismic passive pressure thus obtained shows the linear variation along the height of the retaining wall. There is hardly any scope to find out the point of application of seismic passive resistance by pseudo-static approach but to assume it to act at one-third height from the base of the wall. Rectifying these errors, in recently developed pseudo-dynamic method of analysis, all these factors are considered to compute seismic passive earth pressures. In this paper, an attempt has been made to compute the point of application of seismic passive resistance using limit equilibrium method of analysis with pseudo-dynamic approach. Effects of variation of parameters like wall friction angle, time period of earthquake ground motion, seismic shear and primary wave velocities of backfill soil, soil amplification and seismic peak horizontal and vertical ground accelerations on the seismic passive earth pressure are studied.
Oberst, S & Lai, JCS 1970, 'New approaches for understanding the mechanisms of brake squeal', Annual Conference of the Australian Acoustical Society, AAS'08, pp. 265-272.
View description>>
Brake squeal has become an increasing concern for the automotive industry because of associated warranty costs and the requirement for the continued reduction of interior vehicle noise. Low and high frequency noises in car brakes, often referred to as brake squeal, are known to be a result of nonlinearity, unstable behaviour and bifurcations leading to limit cycle behaviour. By using the data from a separate experimental study designed to determine the influence of the geometric parameters of brake pads (such as the number and location of slots) on brake squeal noise, we examine two new approaches for providing improved understanding of the brake squeal phenomenon: statistical and nonlinear dynamics analyses. Results of the statistical analysis indicate that the performances of certain pad designs correlate with their levels of nonlinearity. The nonlinear time series analysis reveals that, in the experimental data, not only are limit cycle behaviours present but also a route to chaotic solutions can be observed.
Pradhan, B 1970, 'Flood susceptible analysis at Kelantan river basin using remote sensing and logistic regression model', 37th COSPAR Scientific Assembly, p. 2496.
Pradhan, B, Lee, S & Shattri, M 1970, 'Application of a Data Mining Model and It's Cross Application for Landslide Hazard Analysis: a Case Study in Malaysia', 37th COSPAR Scientific Assembly, p. 2495.
Pradhan, B, Mansor, SHATTRI, Lee, S & Buchroithner, MANFREDF 1970, 'Application of data mining model for landslide hazard mapping', Proceedings of ISPRS, pp. 187-196.
Rujikiatkamjorn, C, Ghandeharioon, A & Indraratna, B 1970, 'Finite element simulation of mandrel penetration in a normally consolidated soil', GEOTECHNICS OF SOFT SOILS, 2nd International Workshop on Geotechnics of Soft Soils, Taylor & Francis, Glasgow, SCOTLAND, pp. 287-292.
View/Download from: Publisher's site
Rujikiatkamjorn, C, Ghandeharioon, A & Indraratna, B 1970, 'Modelling of soft ground consolidation via combined surcharge and vacuum preloading', GEOTECHNICS OF SOFT SOILS, 2nd International Workshop on Geotechnics of Soft Soils, Taylor & Francis, Glasgow, SCOTLAND, pp. 43-53.
View/Download from: Publisher's site
Ruzinoor, CM, Rashid, MSA, Rodzi, MA & Biswajeet, P 1970, 'Development of 3D web based terrain visualizer', International Symposium and Exhibition on Geoinformation.
Samali, B, Li, J & Aboura, K 1970, 'Monitoring Bridge Deterioration Using Sensors', 2008 Third International Conference on Broadband Communications, Information Technology & Biomedical Applications, 2008 Third International Conference on Broadband Communications, Information Technology & Biomedical Applications, IEEE, Pretoria, South Africa, pp. 64-69.
View/Download from: Publisher's site
View description>>
Structural health monitoring is a vital part in the management of bridges, particulary as the structures begin to age. Detecting structural faults through the use of sensors is an emerging field that has seen considerable efforts this past decade. Similarly, the use of sensors in bridge management systems provides valuable data on the condition of bridges and external factors affecting the deterioration of bridges such as the traffic load endured by the structures. We review both cases of visual and vibration based monitoring of bridges and showcase an on-line monitoring system for the collection of traffic information. © 2008 IEEE.
Sheng, D & Fredlund, DG 1970, 'Elasto-plastic modelling of unsaturated soils : An overview', 12th International Conference on Computer Methods and Advances in Geomechanics 2008, pp. 2084-2105.
View description>>
This paper presents an overview of elasto-plastic modelling of unsaturated soils. Alternative stress and strain variables that have been used in constitutive models for unsaturated soils are discussed. The use of an effective stress equation may simplify constitutive relations, but often result in a stress space that depends on the material state. In this case, the constitutive behaviour is embodied both in the stress definition and in the constitutive relation. Alternative volumetric models in the literature are then discussed. The focus is placed on the comparison of a new model with other existing models. This new model is formulated in terms of independent stress variables and features a smooth transition between saturated and unsaturated states. The implications of the volumetric model for yield stress and shear strength functions are discussed. The paper also shows how hysteresis in soil-water characteristic curves can be incorporated into the elasto-plastic framework, leading to a coupled hydro-mechanical model. Finally, the paper demonstrates the derivation of the incremental stress-strain relations for unsaturated soils and discusses briefly the implementation of these relations into the finite element method.
Sheng, DC, Pedroso, D & Abbo, AJ 1970, 'Stress path dependency and non-convexity of unsaturated soil models', Unsaturated Soils: Advances in Geo-Engineering - Proceedings of the 1st European Conference on Unsaturated Soils, E-UNSAT 2008, 1st European Conference on Unsaturated Soils, CRC PRESS-TAYLOR & FRANCIS GROUP, Durham, ENGLAND, pp. 705-711.
View description>>
Yield surfaces for unsaturated soils are inevitably non-convex if the size of the yield surface has to increase with increasing suction. An expanding yield surface with increasing suction is crucial for modelling the volume collapse due to wetting. The non-convexity always exists at the transition between saturated and unsaturated states, irrespective of the stress variables used in the model. Some recent models for unsaturated soils also possess a stress path dependent hardening law. The non-convexity and stress-path dependency of the constitutive model make the implementation into finite element codes very challenging. This paper discusses aspects of stress integration schemes for non-convex and stress-path dependent models for unsaturated soils. © 2008 Taylor & Francis Group, London.
Thornton, J, Faichney, J, Blumenstein, M & Hine, T 1970, 'Character Recognition Using Hierarchical Vector Quantization and Temporal Pooling', Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), Springer Berlin Heidelberg, pp. 562-572.
View/Download from: Publisher's site
View description>>
In recent years, there has been a cross-fertilization of ideas between computational neuroscience models of the operation of the neocortex and artificial intelligence models of machine learning. Much of this work has focussed on the mammalian visual cortex, treating it as a hierarchically- structured pattern recognition machine that exploits statistical regularities in retinal input. It has further been proposed that the neocortex represents sensory information probabilistically, using some form of Bayesian inference to disambiguate noisy data. In the current paper, we focus on a particular model of the neocortex developed by Hawkins, known as hierarchical temporal memory (HTM). Our aim is to evaluate an important and recently implemented aspect of this model, namely its ability to represent temporal sequences of input within a hierarchically structured vector quantization algorithm. We test this temporal pooling feature of HTM on a benchmark of cursive handwriting recognition problems and compare it to a current state-of-the-art support vector machine implementation. We also examine whether two pre-processing techniques can enhance the temporal pooling algorithm's performance. Our results show that a relatively simple temporal pooling approach can produce recognition rates that approach the current state-of-the-art without the need for extensive tuning of parameters. We also show that temporal pooling performance is surprisingly unaffected by the use of preprocessing techniques. © 2008 Springer Berlin Heidelberg.
Wang, JC-P, Franklin, DR, Abolhasan, M, Safaei, F & IEEE 1970, 'Characterising the Interactions Between Unicast and Broadcast in IEEE 802.11 Ad Hoc Networks', ATNAC: 2008 AUSTRALASIAN TELECOMMUNICATION NETWOKS AND APPLICATIONS CONFERENCE, ATNAC 2008, In Australasian Telecommunications Networking and Application Conference (ATNAC), Adelaide, SA, pp. 180-185.
View/Download from: Publisher's site
View description>>
This paper investigates the relative performance of unicast and broadcast traffic traversing a one-hop ad hoc network utilising the 802.11 DCF. An extended Markov model has been developed and validated through computer simulation, which successfully predicts the respective performance of unicast and broadcast in a variety of mixed traffic scenarios. Under heavy network traffic conditions, a significant divergence is seen to develop between the performance of the two traffic classes - in particular, when network becomes saturated, unicast traffic is effectively given higher precedence over broadcast. As a result, the network becomes dominated by unicast frames, leading to poor rates of broadcast frame delivery.
Wang, Y & Ye, G 1970, 'Joint Random Fields for Moving Vehicle Detection', Procedings of the British Machine Vision Conference 2008, British Machine Vision Conference 2008, British Machine Vision Association.
View/Download from: Publisher's site
Wang, Y, Li, J, Samali, B & Choi, EC 1970, 'A new non-destructive damage detection method for reinforced concrete beams based on modal strain energy', Futures in Mechanics of Structures and Materials - Proceedings of the 20th Australasian Conference on the Mechanics of Structures and Materials, ACMSM20, Australasian Conference on the Mechanics of Structures and Materials, CRC Press, Toowoomba, pp. 773-779.
View description>>
This paper presents a new non-destructive damage detection algorithm to predict locations and severities of damage in concrete beams based on modal strain energy. The new method only relies on the measured mode shapes from damaged and undamaged states. Furthermore, theoretical development of the new method requires only a simple assumption, that is, structural mass invariability before and after damage. After brief introduction of the new method, Finite Element (FE) models of RC beam are constructed. Structural vibration response time histories of RC beam models are obtained from transient analysis under impact loading. To simulate real life applications, various levels of noise are added to the response time histories. The results from both numerical work and experimental work show that the new method is not only sensitive to damage, but also simple and robust in locating and estimating the severity of damage. © 2009 Taylor & Francis Group, London.
