Indraratna, B, Salim, W & Rujikiatkamjorn, C 2011, Advanced Rail Geotechnology - Ballasted Track, CRC Press.
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Ballast plays a vital role in transmitting and distributing train wheel loads to the underlying sub-ballast and subgrade. Bearing capacity of track, train speed, riding quality and passenger comfort all depend on the stability of ballast through mechanical interlocking of particles. Ballast attrition and breakage occur progressively under heavy cyclic loading, causing track deterioration and rail misalignment-affecting safety and demanding frequent and costly track maintenance. In the absence of realistic constitutive models, the track substructure is traditionally designed using empirical approaches. In Advanced Rail Geotechnology: Ballasted Track, the authors present detailed information on the strength, deformation and degradation, and aspects of fresh and recycled ballast under monotonic, cyclic, and impact loading using innovative geotechnical testing devices. The book presents a new stress-strain constitutive model for ballast incorporating particle breakage and validates mathematical formulations and numerical models using experimental evidence and field trials. The text also elucidates the effectiveness of various commercially available geosynthetics for enhancing track drainage and stability. It presents revised ballast gradations for modern high-speed trains capturing particle breakage and describes the use of geosynthetics in track design. It also provides insight into track design, capturing particle degradation, fouling, and drainage. This book is ideal for final year civil engineering students and postgraduates and is a solid reference for practicing railway engineers and researchers with the task of modernizing existing track designs for heavier and faster trains.
H.R. Pourghasemi, A..Goli Jirandeh 2011, 'Landslide hazard assessment using remote sensing data, GIS and weights-of-evidence model (South of Golestan Province, Iran)' in Advances in Biomedical Engineering, APEST 2012, pp. 30-36.
Lee, J, Guan, H, Blumenstein, M & Loo, YC 2011, 'Improving the reliability of a bridge deterioration model for a decision support system using artificial intelligence' in Chan, T & thambiratnam, DP (eds), Structural Health Monitoring in Australia, Nova Science Publishers, USA, pp. 201-223.
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Bridge Management Systems (BMSs) have been developed since the early 1990s, as a decision support system (DSS) for effective Maintenance, Repair and Rehabilitation (MR&R) activities in a large bridge network. Historical condition ratings obtained from biennial bridge inspections are major resources for predicting future bridge deteriorations through BMSs. However, available historical condition ratings are very limited in all bridge agencies. This constitutes the major barrier for achieving reliable future structural performances. To alleviate this problem, a Backward Prediction Model (BPM) technique has been developed to help generate missing historical condition ratings. Its reliability has been verified using existing condition ratings obtained from the Maryland Department of Transportation, USA. This is achieved through establishing the correlation between known condition ratings and related non-bridge factors such as climate and environmental conditions, traffic volumes and population growth. Such correlations can then be used to determine the bridge condition ratings of the missing years. With the help of these generated datasets, the currently available bridge deterioration model can be utilized to more reliably forecast future bridge conditions. In this chapter, the prediction accuracy based on four and nine BPM-generated historical condition ratings as input data are also compared, using traditional bridge deterioration modeling techniques, i.e., deterministic and stochastic methods. The condition ratings are available. This implies that the BPM can be utilized to generate unavailable historical data, which is crucial for bridge deterioration models to achieve more accurate prediction results. Nevertheless, there are considerable limitations in the existing bridge deterioration models. Thus, further research is essential to improve the prediction accuracy of bridge deterioration models. ©2011 Nova Science Publishers, Inc. All rights reserved.
Pradha, B, Mansor, S & Pirasteh, S 2011, 'Landslide Susceptibility Mapping: an Assessment of the Use of an Advanced Neural Network Model with Five Different Training Strategies' in Artificial Neural Networks-Application, InTech.
Pradhan, B 2011, 'GIScience Tools for Climate Change Related Natural Hazards and Modelling' in Geoinformatics for Climate Change Studies, The Energy and Resources Institute New Delhi, India.
Ruzínoor, CM, Shariff, ARM, Mahmud, AR & Pradhan, B 2011, '3D Terrain Visualisation for GIS: A Comparison of Different Techniques' in Lecture Notes in Geoinformation and Cartography, Springer Berlin Heidelberg, pp. 265-277.
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Wang, Y & Rajapakse, JC 2011, 'DISCRIMINATIVE FRAMEWORK OF NEURAL ACTIVATION ANALYSIS WITH fMRI' in Advanced Topics in Biometrics, WORLD SCIENTIFIC, pp. 483-500.
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(Fred) Cha, D, Zhang, H & Blumenstein, M 2011, 'Prediction of maximum wave-induced liquefaction in porous seabed using multi-artificial neural network model', Ocean Engineering, vol. 38, no. 7, pp. 878-887.
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Al Fugura, A, Billa, L & Pradhan, B 2011, 'Semi-automated procedures for shoreline extraction using single RADARSAT-1 SAR image', Estuarine, Coastal and Shelf Science, vol. 95, no. 4, pp. 395-400.
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AlFugura, A, Billa, L, Pradhan, B, Mohamed, TA & Rawashdeh, S 2011, 'Coupling of hydrodynamic model and aerial photogrammetry-derived digital surface model for flood simulation scenarios using GIS: Kuala Lumpur flood, Malaysia', Malaysia, Disaster Advances, vol. 4, no. 4.
Anbazhagan, P, Buddhima, I & Amarajeevi, G 2011, 'Characterization of Clean and Fouled Rail Track Ballast Subsurface Using Seismic Surface Survey Method: Model and Field Studies', Journal of Testing and Evaluation, vol. 39, no. 5, pp. 831-841.
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Abstract The efficiency of track foundation material gradually decreases due to insufficient lateral confinement, ballast fouling, and loss of shear strength of the subsurface soil under cyclic loading. This paper presents characterization of rail track subsurface to identify ballast fouling and subsurface layers shear wave velocity using seismic survey. Seismic surface wave method of multi-channel analysis of surface wave (MASW) has been carried out in the model track and field track for finding out shear wave velocity of the clean and fouled ballast and track subsurface. The shear wave velocity (SWV) of fouled ballast increases with increase in fouling percentage, and reaches a maximum value and then decreases. This character is similar to typical compaction curve of soil, which is used to define optimum and critical fouling percentage (OFP and CFP). Critical fouling percentage of 15 % is noticed for Coal fouled ballast and 25 % is noticed for clayey sand fouled ballast. Coal fouled ballast reaches the OFP and CFP before clayey sand fouled ballast. Fouling of ballast reduces voids in ballast and there by decreases the drainage. Combined plot of permeability and SWV with percentage of fouling shows that after critical fouling point drainage condition of fouled ballast goes below acceptable limit. Shear wave velocities are measured in the selected location in the Wollongong field track by carrying out similar seismic survey. In-situ samples were collected and degrees of fouling were measured. Field SWV values are more than that of the model track SWV values for the same degree of fouling, which might be due to sleeper’s confinement. This article also highlights the ballast gradation widely followed in different countries and presents the comparison of Indian ballast gradation with international gradation standards. Indian ballast contains a coarser particle size when compared to other countries. The upper ...
Anbazhagan, P, Lijun, S, Buddhima, I & Cholachat, R 2011, 'Model track studies on fouled ballast using ground penetrating radar and multichannel analysis of surface wave', Journal of Applied Geophysics, vol. 74, no. 4, pp. 175-184.
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Ansari, Y, Merifield, R, Yamamoto, H & Sheng, D 2011, 'Numerical analysis of soilbags under compression and cyclic shear', Computers and Geotechnics, vol. 38, no. 5, pp. 659-668.
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Barua, B, Abolhasan, M & Safaei, F 2011, 'On the Symbol Error Probability of Multihop Parallel Relay Networks', IEEE COMMUNICATIONS LETTERS, vol. 15, no. 7, pp. 719-721.
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In this paper we analyze the symbol error probability (SEP) of a cooperative multihop parallel relay network in Rayleigh fading channels for M-ary Phase-shift keying (M-PSK) modulation. The general closed form expression of the SEP is derived. We present numerical results on the performance of the network.
Barua, B, Abolhasan, M, Safaei, F & Franklin, DR 2011, 'On the Error Exponent of Amplify and Forward Relay Networks', IEEE COMMUNICATIONS LETTERS, vol. 15, no. 10, pp. 1047-1049.
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In this letter we derive the exact random coding error exponent of a dual hop amplify and forward (AF) relay network with channel state information (CSI) assisted ideal relay gain. Numerical results have been presented, which provide insight about the performance tradeoff between the error exponent and the data rate of the network. Finally we present the capacity analysis of this relay network.
Bolch, T, Peters, J, Yegorov, A, Pradhan, B, Buchroithner, M & Blagoveshchensky, V 2011, 'Identification of potentially dangerous glacial lakes in the northern Tien Shan', Natural Hazards, vol. 59, no. 3, pp. 1691-1714.
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Cheng, S, Ji, JC & Zhou, J 2011, 'Infinite-time and finite-time synchronization of coupled harmonic oscillators', PHYSICA SCRIPTA, vol. 84, no. 3, pp. 1-8.
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This paper studies the infinite-time and finite-time synchronization of coupled harmonic oscillators with distributed protocol in the scenarios with and without a leader. In the absence of a leader, the convergence conditions and the final trajectories that each harmonic oscillator follows are developed. In the presence of a leader, it is shown that all harmonic oscillators can achieve the trajectory of the leader in finite time. Numerical simulations of six coupled harmonic oscillators are given to show the effects of the interaction function parameter, algebraic connectivity and initial conditions on the convergence time. © 2011 The Royal Swedish Academy of Sciences.
Farrokhnia, A, Pirasteh, S, Pradhan, B, Pourkermani, M & Arian, M 2011, 'A recent scenario of mass wasting and its impact on the transportation in Alborz Mountains, Iran using geo-information technology', Arabian Journal of Geosciences, vol. 4, no. 7-8, pp. 1337-1349.
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Fatahi, B, Engelbert, D, Mujic, S & Khabbaz, H 2011, 'Effects of preloading on soft clay improvement using Deep Soil Mixing', Australian Geomechanics Journal, vol. 46, no. 3, pp. 63-71.
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Poor performing soils, particularly soft clays, are more prevalent around lakes and coastal environments, where demand for construction is generally higher. It is therefore critical that suitable ground improvement techniques be developed and refined to ensure these sites perform satisfactorily under applied structural loads. There is a clear trend in geotechnical construction to further develop technologies such as Deep Soil Mixing (DSM), using cement, lime, fly ash or bottom ash, with an aim to improve the mechanical properties of problematic soils. In this study, the influence of surcharge (10 kPa to 120 kPa) applied during curing on soil-cement columns is investigated using two different clay types, namely kaolinite and bentonite. Preload provides confinement and pre-compression during curing, which in turn increases the bearing capacity of the treated ground. The results of unconfined compressive strength tests are analysed to illustrate how the mechanical properties of the clays composed of differing cement content are influenced under varying surcharges applied instantly after mixing. The results indicate that mechanical properties of cement treated soft clays, including strength and stiffness can be enhanced through the application of surcharge immediately after construction, during the curing phase. This could potentially provide a cost effective and environmentally friendly alternative by reducing the required cement content being added to soil to achieve a given strength.
Fatahi, B, Khabbaz, H & Ho, HL 2011, 'Effects of geotextiles on drainage performance of ballasted rail tracks', Australian Geomechanics Journal, vol. 46, no. 4, pp. 91-102.
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Naturally soft soils are mostly found around coastal regions, where the construction of ballasted rail tracks is required to have a more thorough consideration regarding filtration. Any poor filter design on weak ground inevitably leads to a critical change in ballast characteristics. It is noticeable that such a change results in several issues including significant migration of finer particles about the subballast-subgrade interface and the deficiency of subballast filtration. These problems eventually reduce the drainage ability of the rail sub-system and may cause severe damage which can only be remedied by frequent and costly track maintenance. It is therefore important that geosynthetics such as geotextiles are introduced to the rail track system as an additional filter layer, which is able to retain the desirable filtering characteristics. This paper investigates the impact of non-woven geotextiles on filtration behaviour of subballast in the laboratory, while adopting different granular filter (subballast) thicknesses varying from 0 mm to 50 mm. The research findings demonstrate a notable difference in the cumulative fine loss per unit volume within a given period of time between two distinctive tests - with and without geotextiles, thus emphasising the beneficial application of this geosynthetic material. Empirical estimation of permeability and properties of subballast, including grading curves after testing, are carefully carried out and the results are presented in this paper. The results indicate that the thickness of granular subballast can be significantly reduced by including geotextiles. This paper, in turn, evaluates the potential combination of the track substructure and geotextiles to achieve the optimum filter design and more importantly, alleviate the cost of track maintenance.
Fatahi, B, Khabbaz, SH & Basack, S 2011, 'Effects of salinity and sand content on liquid limit and hydraulic conductivity', Australian Geomechanics Journal, vol. 46, no. 1, pp. 67-76.
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Soil conditions of construction sites have become worse than ever due to the overpopulation in the metropolitan areas throughout the world. Likewise, the prevention of environmental risks due to individual activities is one of the most important subjects in the geo-environmental problems. Saline soils may induce several problems in geotechnical engineering projects such as infrastructure embankments, road construction and clay liners. Effect of the various concentrations of sodium chloride (NaCl) on several different soils including bentonite, kaolinite and fine sand mixtures has been evaluated. In addition, influence of salinity and the period of submergence on the hydraulic conductivity of soil samples collected from a certain area of east coast of India was investigated. The results show that the liquid limit of the mixtures generally decreases with an increase in the salt concentration. Liquid limit decreased significantly with an increase in NaCl concentration up to a certain level. However, a further increase in the concentration does not induce any significant decrease in liquid limit. Furthermore, the soil hydraulic conductivity increase with the salt concentration and with increase in the period of submergence, the hydraulic conductivity of the soil increases asymptotically.
Fredlund, DG, Sheng, D & Zhao, J 2011, 'Estimation of soil suction from the soil-water characteristic curve', Canadian Geotechnical Journal, vol. 48, no. 2, pp. 186-198.
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Soil-water characteristic curves (SWCCs) are routinely used for the estimation of unsaturated soil property functions (e.g., permeability functions, water storage functions, shear strength functions, and thermal property functions). This paper examines the possibility of using the SWCC for the estimation of in situ soil suction. The paper focuses on the limitations of estimating soil suctions from the SWCC and also suggests a context under which soil suction estimations should be used. The potential range of estimated suction values is known to be large because of hysteresis between drying and wetting SWCCs. For this, and other reasons, the estimation of in situ suctions from the SWCC has been discouraged. However, a framework is suggested in this paper for estimating the median value for in situ soil suction along with a likely range of soil suction values (i.e., maximum and minimum values). The percentage error in the estimation of soil suction from the SWCC is shown to be lowest for sand soils and highest for clay soils.
Fugura, AA, Billa, L, Pradhan, B, Mohamed, TA & Rawashdeh, S 2011, 'Coupling of hydrodynamic modeling and aerial photogrammetry-derived digital surface model for flood simulation scenarios using GIS: Kuala Lumpur flood, Malaysia', Disaster Advances, vol. 4, no. 4, pp. 20-28.
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Hydrological simulations are useful methods of assessing and testing different scenarios of the impact of a hydrological event on a hydrological environment. Their effect and efficiency are however limited without the support of spatial planning tools such as GIS. GIS provides the platform for simulations to be integrated with supporting basin and floodplain data to be projected spatially and visualized spatially in support of decision making. Kuala Lumpur, Malaysia is experiencing frequent floods due to the rapid expansion of the city and increasing intensity of monsoon rainfall. In this study hydrodynamic simulation is coupled with a well developed digital surface and terrain model (DEM) to map flood extent in Kuala Lumpur. Techniques and methods discuss the integration of hydrological processes, remote sensing and GIS processing in 3D hydrological GIS modeling to represent different flooding scenarios.
Geng, X, Indraratna, B & Rujikiatkamjorn, C 2011, 'Effectiveness of partially penetrating vertical drains under a combined surcharge and vacuum preloading', Canadian Geotechnical Journal, vol. 48, no. 6, pp. 970-983.
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This paper considers the consolidation of a layer of clay in which partially penetrating prefabricated vertical drains (PVDs) are used in conjunction with a combined surcharge and vacuum preloading. Analytical solutions for partially penetrating PVDs are derived by considering vacuum pressure (suction), time-dependent embankment surcharge, well resistance, and smear zone. Three-dimensional seepage with a virtual vertical drain is assumed to reflect real seepage into the soil beneath the tip of a PVD. Analytical solutions were then used to examine the length of the vertical drain and vacuum pressure on soft clay to determine the consolidation time and degree of consolidation, associated settlement, and distribution of suction along the drain. The proposed solutions are then employed to analyse a case history. Finally, an appropriate PVD length in relation to clay thickness and drain spacing is recommended for various loading patterns.
Ghobadi, Y, Pirasteh, S, Pradhan, B, Ahmad, NB, Shafri, HZBM, Sayyad, GA & Kabiri, K 2011, 'Determine of correlation coefficient between EPM and MPSIAC models and generation of erosion maps by GIS techniques in Baghmalek watershed, Khuzestan, Iran', 5thSASTech, Khavaran Highereducation Institute, Mashhad, Iran.
Guruprasad, B, Indraratna, B, Nghiem, LD & Regmi, G 2011, 'A neural network approach to predict the performance of recycled concrete used in permeable reactive barriers for the treatment of acidic groundwater', Quarterly Journal of Engineering Geology and Hydrogeology, vol. 44, no. 2, pp. 199-209.
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Hokmabadi, AS, Fakher, A & Fatahi, B 2011, 'Seismic Strain Wedge Model for analysis of single piles under lateral seismic loading', Australian Geomechanics Journal, vol. 46, no. 1, pp. 31-41.
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One of the most effective methods of analysing a single pile and pile groups under lateral loading is Strain Wedge Model (SWM). SWM has a number of advantages in comparison with traditional p-y curves, but this model could traditionally only be used to analyse piles under monotonie loads. In the present paper, SWM has been modified to consider dynamic lateral loading. Based on this new method, called Seismic Strain Wedge Model (SSWM), a computer code has been developed for lateral analysis of piles. Using this computer code, some case studies have been analysed and the results show good agreement with test data. This paper introduces SSWM as a simple and powerful solution to analyse piles under lateral seismic loading.
Huang, M, Liu, Y & Sheng, D 2011, 'Simulation of yielding and stress–stain behavior of shanghai soft clay', Computers and Geotechnics, vol. 38, no. 3, pp. 341-353.
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Indraratna, B, Ngo, NT & Rujikiatkamjorn, C 2011, 'Behavior of geogrid-reinforced ballast under various levels of fouling', Geotextiles and Geomembranes, vol. 29, no. 3, pp. 313-322.
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This paper presents a study of how the interface between ballast and geogrid copes with fouling by coal fines. The stress-displacement behavior of fresh and fouled ballast, and geogrid reinforced ballast was investigated through a series of large-scale direct shear tests where the levels of fouling ranged from 0% to 95% Void Contamination Index (VCI), at relatively low normal stresses varying from 15 kPa to 75 kPa. The results indicated that geogrid increases the shear strength and apparent angle of shearing resistance, while only slightly reducing the vertical displacement of the composite geogrid-ballast system. However, when ballast was fouled by coal fines, the benefits of geogrid reinforcement decreased in proportion to the increasing level of fouling. A conceptual normalized shear strength model was proposed to predict this decrease in peak shear stress and peak angle of shearing resistance caused by coal fines at a given normal stress. © 2011.
Indraratna, B, Nguyen, VT & Rujikiatkamjorn, C 2011, 'Assessing the Potential of Internal Erosion and Suffusion of Granular Soils', Journal of Geotechnical and Geoenvironmental Engineering, vol. 137, no. 5, pp. 550-554.
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Indraratna, B, Rujikiatkamjorn, C, Ameratunga, J & Boyle, P 2011, 'Performance and Prediction of Vacuum Combined Surcharge Consolidation at Port of Brisbane', Journal of Geotechnical and Geoenvironmental Engineering, vol. 137, no. 11, pp. 1009-1018.
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Indraratna, B, Rujikiatkamjorn, C, Geng, X-Y, McIntosh, G & Kelly, R 2011, 'Soft Soils Improved by Prefabricated Vertical Drains: Performance and Prediction', Soils and Rocks, vol. 34, no. 4, pp. 379-388.
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The use of prefabricated vertical drains with vacuum preloading and surcharge preloading is now common practice and is proving to be one of the most effective ground improvement techniques known. The factors affecting its performance, such as the smear zone, the drain influence zone, and drain unsaturation, are discussed in this paper. In order to evaluate these effects a large scale consolidation test was conducted and it was found that the proposed Cavity Expansion Moreover, the procedure for converting an equivalent 2-D plane strain multi-drain analysis that considers the smear zone and vacuum pressure are also described. The conversion procedure was incorporated into finite element codes using a modified Cam-clay theory. Numerical analysis was conducted to predict excess pore pressure and lateral and vertical displacement. Three case histories are analyzed and discussed, including the sites of Muar clay (Malaysia), the Second Bangkok International Airport (Thailand), and the Sandgate railway line (Australia). The predictions were then compared with the available field data, which include settlement, excess pore pressure, and lateral displacement. Further findings verified that smear, drain unsaturation, and vacuum distribution can significantly influence consolidation so they must be modeled appropriately in any numerical analysis to obtain reliable predictions.
Indraratna, B, Su, L-J & Rujikiatkamjorn, C 2011, 'A new parameter for classification and evaluation of railway ballast fouling', Canadian Geotechnical Journal, vol. 48, no. 2, pp. 322-326.
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The physical condition of railway ballast should be regularly inspected and accordingly, ballast cleaning should be carried out to maintain the safe operation of a track. This paper reviews current methods commonly used for evaluating the degree of ballast fouling, and due to their limitations, a new parameter — “relative ballast fouling ratio”— is proposed. Categories of fouling based on the proposed method are derived from the particle gradation curves taken from past literature. Comparisons between these methods demonstrate that the newly proposed relative ballast fouling ratio would best represent the influence of the type and gradation of fouling material.
Jadda, M, Shafri, HZM & Mansor, SB 2011, 'PFR model and GiT for landslide susceptibility mapping: a case study from Central Alborz, Iran', Natural Hazards.
Ji, JC & Zhang, N 2011, 'Suppression of super-harmonic resonance response using a linear vibration absorber', MECHANICS RESEARCH COMMUNICATIONS, vol. 38, no. 6, pp. 411-416.
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Super-harmonic resonances may appear in the forced response of a weakly nonlinear oscillator having cubic nonlinearity, when the forcing frequency is approximately equal to one-third of the linearized natural frequency. Under super-harmonic resonance conditions, the frequency-response curve of the amplitude of the free-oscillation terms may exhibit saddle-node bifurcations, jump and hysteresis phenomena. A linear vibration absorber is used to suppress the super-harmonic resonance response of a cubically nonlinear oscillator with external excitation. The absorber can be considered as a small mass-spring-damper oscillator and thus does not adversely affect the dynamic performance of the nonlinear primary oscillator. It is shown that such a vibration absorber is effective in suppressing the super-harmonic resonance response and eliminating saddle-node bifurcations and jump phenomena of the nonlinear oscillator. Numerical examples are given to illustrate the effectiveness of the absorber in attenuating the super-harmonic resonance response. © 2011 Elsevier Ltd. All rights reserved.
Lee, JH, Guan, H, Loo, YC, Blumenstein, M & Wang, XP 2011, 'Modelling Long-Term Bridge Deterioration at Structural Member Level Using Artificial Intelligence Techniques', Applied Mechanics and Materials, vol. 99-100, pp. 444-453.
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Efficient use of public funds for structural integrity of bridge networks requires an effective bridge asset management technology. To achieve this, a reliable deterioration model is essential in any Bridge Management System (BMS). The deterioration rate is calculated based on historical condition ratings obtained from the structural element-level bridge inspections. Although most bridge authorities have previously conducted inspection and maintenance tasks, these past inspection records are incompatible with what are required by a typical BMS as input. Such incompatibility is a major cause for the deficiency of the current BMS outcomes. Artificial Intelligence (AI)-based bridge deterioration model has recently been developed to minimise uncertainties in predicting deterioration of structural bridge members (e.g. beams, piers etc). This model contains two components: (1) using Neural Network-based Backward Prediction Model (BPM) to generate unavailable historical condition ratings; and (2) using Time Delay Neural Network (TDNN) to perform long-term performance prediction of bridge structural members. However new problems have emerged in the process of TDNN prediction. This is because the BPM-generated condition ratings are used together with the actual condition ratings. The incompatibility between the two sets of data produces unreliable prediction outcomes during the TDNN process. This research is thus to develop a new process based on the existing method, thereby overcoming the abovementioned problems. To achieve this, the actual overall condition ratings are replaced by the BPM forward predicted condition ratings. Consequently, the outcome of this study can improve accuracy of long-term bridge deterioration prediction.
Li, J, Dackermann, U, Xu, Y-L & Samali, B 2011, 'Damage identification in civil engineering structures utilizing PCA-compressed residual frequency response functions and neural network ensembles', STRUCTURAL CONTROL & HEALTH MONITORING, vol. 18, no. 2, pp. 207-226.
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This paper presents a non-destructive, global, vibration-based damage identification method that utilizes damage pattern changes in frequency response functions (FRFs) and artificial neural networks (ANNs) to identify defects. To extract damage features and to obtain suitable input parameters for ANNs, principal component analysis (PCA) techniques are applied. Residual FRFs, which are the differences in the FRF data from the intact and the damaged structure, are compressed to a few principal components and fed to ANNs to estimate the locations and severities of structural damage. A hierarchy of neural network ensembles is created to take advantage of individual information from sensor signals. To simulate fieldtesting conditions, white Gaussian noise is added to the numerical data and a noise sensitivity study is conducted to investigate the robustness of the developed damage detection technique to noise. Both numerical and experimental results of simply supported steel beam structures have been used to demonstrate effectiveness and reliability of the proposed method.
Liu, MD & Indraratna, BN 2011, 'General Strength Criterion for Geomaterials Including Anisotropic Effect', International Journal of Geomechanics, vol. 11, no. 3, pp. 251-262.
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Mahmoud, A, Elbialy, S, Pradhan, B & Buchroithner, M 2011, 'Field-based landcover classification using TerraSAR-X texture analysis', Advances in Space Research, vol. 48, no. 5, pp. 799-805.
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Mat, RC, Shariff, ARM, Pradhan, B & Mahmud, AR 2011, 'Online 3D terrain visualization of GIS data: A comparison between three different web servers', Pertanika Journal of Science and Technology, vol. 19, no. SPEC. ISSUE, pp. 31-39.
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Geographical Information Systems (GIS) and three dimensional (3D) World Wide Web (WWW) applications usage are on the rise. The demand for online 3D terrain visualization for GIS data has increased. Current users demand for more complex data which have higher accuracy and realism. This is aided by the emergence of geo-browsers in the market which provide free service and also cater for the commercialized market. Other new technology driving the market is the use of software such as CityGML, Virtual Reality Markup Language (VRML)/ Entensive 3D (X3D), geoVRML, and Keyhole Markup Language (KML). These technologies also play an important role for this new era of online 3D terrain visualization. The aim of this paper is to implement the online 3D terrain visualization for GIS data by using VRML technology and launching the system into three different web servers. The data used for this system are contour data and high resolution satellite image (QUICKBIRD) for Universiti Putra Malaysia (UPM) area. Testing was done only for satellite image overlaid to 3D terrain data. The web servers used in this experiment were the Spatial Research Group Server in UPM, Universiti Utara Malaysia (UUM) web server, and ruzinoor.my web server. The comparison was based on the performance of web servers in terms of accessibility, uploading time, CPU usage, frame rate per second (fps), and number of users. The results from this experiment will be of help and guidance to the developers in finding the right web servers for the best performance on implementing online 3D terrain visualization for GIS data. © Universiti Putra Malaysia Press.
Motlaq, KS, Pirasteh, S, Norozi, OA, Pradhan, B & Mahmoodzadeh, A 2011, 'Sinkholes mapping using gis: vulnarebility and risk assessment emphasis on development areas', International Geoinformatics Research and Development Journal, vol. 2, no. 2, pp. 49-61.
Mousavi, SR, Pirasteh, S, Pradhan, B, Mansor, S & Mahmud, AR 2011, 'The ASTER DEM generation for geomorphometric analysis of the Central Alborz mountains, Iran', Pertanika Journal of Science and Technology, vol. 19, no. SPEC. ISSUE, pp. 115-124.
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This research focuses on the ASTER DEM generation for visual and mathematical analysis of topography, landscapes and landforms, as well as modeling of surface processes of Central Alborz, Iran. ASTER DEM 15 m generated using tie points over the Central Alborz and Damavand volcano with 5671 m height from ASTER (Advanced Space borne Thermal Emission and Reflection Radiometer) satellite data using PCI Geomatica 9.1. Geomorphic parameters are useful to identify and describe geomorphologic forms and processes, which were extracted from ASTER DEM in GIS environment such as elevation, aspect, slope angle, vertical curvature, and tangential curvature. Although the elevation values are slightly low in altitudes above 5500 m asl., the ASTER DEM is useful in interpretation of the macro- and meso-relief, and provides the opportunity for mapping especially at medium scales (1:100,000 and 1:50,000). ASTER DEM has potential to be a best tool to study 3D model for to geomorphologic mapping and processes of glacial and per glacial forms above 4300 m asl. © Universiti Putra Malaysia Press.
Movassaghi, S, Abolhasan, M & Lipman, J 2011, 'Addressing Schemes for Body Area Networks', IEEE COMMUNICATIONS LETTERS, vol. 15, no. 12, pp. 1310-1313.
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This letter explores address allocation in Body Area Networks (BANs) and proposes two novel schemes - Optimized Prophet Address Allocation (OPAA) and Hierarchical Collision-free Address Protocol (HCAP). The aim of the schemes is to use fewer bits in the address space, solve address wastage problems, reduce collisions and improve power efficiency. The usability and efficiency of the proposed schemes is shown through simulation and analysis. © 2006 IEEE.
Oberst, S & Lai, JCS 2011, 'Chaos in brake squeal noise', Journal of Sound and Vibration, vol. 330, no. 5, pp. 955-975.
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Oberst, S & Lai, JCS 2011, 'Statistical analysis of brake squeal noise', Journal of Sound and Vibration, vol. 330, no. 12, pp. 2978-2994.
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Oh, H-J & Pradhan, B 2011, 'Application of a neuro-fuzzy model to landslide-susceptibility mapping for shallow landslides in a tropical hilly area', Computers & Geosciences, vol. 37, no. 9, pp. 1264-1276.
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Pirasteh, S, Pradhan, B & Rizvi, SM 2011, 'Tectonic process analysis in Zagros Mountain with the aid of drainage networks and topography maps dated 1950–2001 in GIS', Arabian Journal of Geosciences, vol. 4, no. 1-2, pp. 171-180.
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Pirasteh, S, Pradhan, B & Rizvi, SM 2011, 'تحليل الحركات الزلزالية و العمليات التكتونيه لجبال زاجروس في جنوب إيران بأستحدام و تحليل خرائط متعددة زمنيا لاتجاهات ومسارات المجاري المائية الطبيعية والأنهار منذ العام-2001 في بيئيه نظم المعلومات الجغرافية', Arabian Journal of Geosciences, vol. 4, no. 1, p. 171.
Pradhan, B 2011, 'An Assessment of the Use of an Advanced Neural Network Model with Five Different Training Strategies for the Preparation of Landslide Susceptibility Maps', Journal of Data Science, vol. 9, no. 1, pp. 65-81.
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Pradhan, B 2011, 'Hydro-Chemical Analysis of the Ground Water of the Basaltic Catchments: Upper Bhatsai Region, Maharastra', The Open Hydrology Journal, vol. 4, no. 1, pp. 51-57.
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Pradhan, B 2011, 'Manifestation of an advanced fuzzy logic model coupled with Geo-information techniques to landslide susceptibility mapping and their comparison with logistic regression modelling', Environmental and Ecological Statistics, vol. 18, no. 3, pp. 471-493.
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Pradhan, B 2011, 'Use of GIS-based fuzzy logic relations and its cross application to produce landslide susceptibility maps in three test areas in Malaysia', Environmental Earth Sciences, vol. 63, no. 2, pp. 329-349.
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Pradhan, B & Youssef, AM 2011, 'A 100-year maximum flood susceptibility mapping using integrated hydrological and hydrodynamic models: Kelantan River Corridor, Malaysia', Journal of Flood Risk Management, vol. 4, no. 3, pp. 189-202.
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Pradhan, B, Mansor, S, Pirasteh, S & Buchroithner, MF 2011, 'Landslide hazard and risk analyses at a landslide prone catchment area using statistical based geospatial model', International Journal of Remote Sensing, vol. 32, no. 14, pp. 4075-4087.
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Rajab, JM, Jafri, MZM, Lim, HS & Abdullah, K 2011, 'Monthly Distribution Map of Carbon Monoxide (CO) from AIRS over Peninsular Malaysia, Sabah and Sarawak for the year 2003', PERTANIKA JOURNAL OF SCIENCE AND TECHNOLOGY, vol. 19, pp. 89-96.
Regmi, G, Indraratna, B, Nghiem, LD & Banasiak, L 2011, 'Evaluating waste concrete for the treatment of acid sulphate soil groundwater from coastal floodplains', Desalination and Water Treatment, vol. 32, no. 1-3, pp. 126-132.
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Regmi, G, Indraratna, B, Nghiem, LD, Golab, A & Prasad, BG 2011, 'Treatment of Acidic Groundwater in Acid Sulfate Soil Terrain Using Recycled Concrete: Column Experiments', Journal of Environmental Engineering, vol. 137, no. 6, pp. 433-443.
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Ruzinoor, CM, Shariff, ARM, Mahmud, AR & Pradhan, B 2011, 'Online 3D Terrain Visualization: Implementation and Testing', Journal of Applied Sciences, vol. 11, no. 18, pp. 3247-3257.
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Sabbagh, AA, Braun, R & Abolhasan, M 2011, 'A comprehensive survey on rat selection algorithms for heterogeneous networks', World Academy of Science, Engineering and Technology, vol. 73, pp. 141-145.
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Due to the coexistence of different Radio Access Technologies (RATs), Next Generation Wireless Networks (NGWN) are predicted to be heterogeneous in nature. The coexistence of different RATs requires a need for Common Radio Resource Management (CRRM) to support the provision of Quality of Service (QoS) and the efficient utilization of radio resources. RAT selection algorithms are part of the CRRM algorithms. Simply, their role is to verify if an incoming call will be suitable to fit into a heterogeneous wireless network, and to decide which of the available RATs is most suitable to fit the need of the incoming call and admit it. Guaranteeing the requirements of QoS for all accepted calls and at the same time being able to provide the most efficient utilization of the available radio resources is the goal of RAT selection algorithm. The normal call admission control algorithms are designed for homogeneous wireless networks and they do not provide a solution to fit a heterogeneous wireless network which represents the NGWN. Therefore, there is a need to develop RAT selection algorithm for heterogeneous wireless network. In this paper, we propose an approach for RAT selection which includes receiving different criteria, assessing and making decisions, then selecting the most suitable RAT for incoming calls. A comprehensive survey of different RAT selection algorithms for a heterogeneous wireless network is studied.
Sezer, EA, Pradhan, B & Gokceoglu, C 2011, 'Manifestation of an adaptive neuro-fuzzy model on landslide susceptibility mapping: Klang valley, Malaysia', Expert Systems with Applications, vol. 38, no. 7, pp. 8208-8219.
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Shao, W, Bouzerdoum, A, Phung, SL, Su, L, Indraratna, B & Rujikiatkamjorn, C 2011, 'Automatic Classification of Ground-Penetrating-Radar Signals for Railway-Ballast Assessment', IEEE Transactions on Geoscience and Remote Sensing, vol. 49, no. 10, pp. 3961-3972.
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Sheng, D 2011, 'Review of fundamental principles in modelling unsaturated soil behaviour', Computers and Geotechnics, vol. 38, no. 6, pp. 757-776.
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Sheng, D & Zhou, A-N 2011, 'Coupling hydraulic with mechanical models for unsaturated soils', Canadian Geotechnical Journal, vol. 48, no. 5, pp. 826-840.
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This paper presents an alternative method to couple the hydraulic component with the mechanical component in a constitutive model for unsaturated soils. Some pioneering work on hydromechanical coupling is reviewed. Generalized constitutive relations on coupled hydromechanical behaviour are introduced. These generalized constitutive relations are then incorporated into existing mechanical and hydraulic models for unsaturated soils. A new coupling mechanism is proposed based on the fact that soil-water characteristic equations are usually obtained for constant stress, not constant volume. The proposed coupling mechanism also satisfies the intrinsic relationship between the degree of saturation and the volumetric strain for undrained compression. Numerical examples are presented to show the performance of the proposed model in predicting soil behaviour along drying and loading paths. Finally, the model is validated against experimental data for different soils.
Sheng, D, Augarde, CE & Abbo, AJ 2011, 'A fast algorithm for finding the first intersection with a non-convex yield surface', Computers and Geotechnics, vol. 38, no. 4, pp. 465-471.
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Sheng, D, Zhou, A & Fredlund, DG 2011, 'Shear Strength Criteria for Unsaturated Soils', Geotechnical and Geological Engineering, vol. 29, no. 2, pp. 145-159.
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Shear strength is one of the fundamental properties of unsaturated soils. It has been found to change with matric suction. Various shear strength equations have been proposed for predicting the shear strength versus suction relationship for unsaturated soils. Some of these equations are based on regression analysis of experimental data, while some are embodied in more complex stress-strain constitutive models. In this paper, a variety of shear strength equations are examined and compared with respect to their fit of experimental data. Data for specimens prepared from initially slurry conditions as well as data for initially compacted soil specimens are analysed. The advantages and limitations associated with various proposed shear strength equations are discussed in this paper. © 2009 Springer Science+Business Media B.V.
Yancheng, LI, Jianchun, LI & SAMALI, B 2011, 'Dynamic Performance of a Novel Magnetorheological Pin Joint', Journal of System Design and Dynamics, vol. 5, no. 5, pp. 706-715.
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Magnetorheological fluid (MRF) has received significant attention lately and MRF based devices have been proposed for structural control applications in recent years. The unique characteristics of MR fluid lies in its abilities to reversibly, repeatedly and instantly change from a free flowing liquid to a semi-solid state when exposed to a magnetic field. The electric power required to drive the MR devices can be easily provided by a battery. Possessing such unique properties, MR fluid based devices, such as MR damper, have become promising candidates in the semi-active control for civil structure applications. However, most of the published research has focused on application of MR dampers instead of exploring other type of MR devices. In addition, MR based devices exhibit complex nonlinear hysteresis behaviour and thus making their modelling a challenging task.
In this paper, a novel MR fluid based device, namely MR pin joint, is proposed as a smart structural member in development of an intelligent civil structure that can suppress unwanted vibrations to ensure safety and serviceability of the structure. After design and fabrication, experiments have been conducted to characterise dynamic behaviours of the new device under different harmonic excitations with various input currents. Response time of the MR pin joint is compared when the MR pin joint is driven under different applied currents and moving speeds. Test data shows that the MR pin joint possesses a unique behaviour in the moment-angular velocity plot. A hyperbolic hysteresis model is proposed to model such unique behaviour. The investigation presented in the paper explores dynamic performance of MR pin joint. Finally, a parametric model is developed following the investigation on the correlation of coefficients in the proposed model with the loading conditions and applied currents.
Yang, L, Ji, J, Hu, J & Ning, L 2011, 'Prediction of Process Parameters on Stress and Strain Fields in Hot Rolling Process using Finite Element Method', Information Technology Journal, vol. 10, no. 12, pp. 2406-2412.
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To predict the distribution of stress and strain fields in hot rolling process, the computer models are built using rigid-plastic finite element method and are calculated using up-dated Lagrange method. The workpiece and the work-roll are defined as the deformation body and the rigid body with heat transfer, respectively. All kinds of heat boundary conditions, initial boundary and heat generation are introduced in the model. The analysis is capable of considering the effects of various parameters such as rolling speed, reduction ratio and tension rolling on effective strain, effective stress, contact normal stress and friction stress. In addition, the distributions of stress and strain and strain history are also calculated along contact arc length and thickness direction in the hot rolling process. To assess the reliability of the numerical analysis, a comparison is made between the prediction results and published literature and a reasonable agreement is obtained in this study. © 2011 Asian Network for Scientific Information.
Yang, L, Ji, J, Hu, J & Romagos, A 2011, 'Effect of process parameters on mechanical behavior in hot-slab rolling', MECHANIKA, vol. 17, no. 5, pp. 474-479.
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This paper studies hot rolling process of typical low carbon steel by using rigid-plastic finite element method. Numerical simulations are carried out to examine the effects of the percentage of reduction rate, work-roll radius, frictional coefficient, rolling speed, tension, initial rolling temperature and initial slab thickness on rolling force and deformation behavior of the slab. It is found that rolling force increases with the increases of reduction rate, rolling speed, frictional coefficient and radius. The initial rolling temperature, initial slab thickness and tension have also important effects on rolling force, and it will decreases remarkably by increasing the parameters. Moreover, it is also found that rolling force remains unchanged when ini-tial slab temperature reaches certain value. The friction and effective stress distribution in the slab are obtained for the steady-state rolling process. The positive friction in back-ward slip zone is found to be greater than the negative fric-tion in forward slip zone along rolling direction, indicating that friction acts as the driving force in the rolling process.
Youssef, AM, Pradhan, B & Hassan, AM 2011, 'Flash flood risk estimation along the St. Katherine road, southern Sinai, Egypt using GIS based morphometry and satellite imagery', Environmental Earth Sciences, vol. 62, no. 3, pp. 611-623.
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Youssef, AM, Pradhan, B & Tarabees, E 2011, 'Integrated evaluation of urban development suitability based on remote sensing and GIS techniques: contribution from the analytic hierarchy process', Arabian Journal of Geosciences, vol. 4, no. 3-4, pp. 463-473.
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Zainol, R, Abu Bakar, Z & Ali, SJS 2011, 'Integrated Partial Match Query in Geographic Information Retrieval', PERTANIKA JOURNAL OF SCIENCE AND TECHNOLOGY, vol. 19, pp. 41-49.
Al Sabbagh, A, Braun, RM & Abolhasan, M 1970, 'A Comprehensive Survey on RAT Selection Algorithms for Beyond 3G Networks', International Conference on Communications, Networking and Mobile Computing (ICCNMC 2011), International Conference on Computer Networks and Mobile Computing, World Academy of Science, Engineering and Technology - WASET, Dubai, pp. 834-838.
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Due to the coexistence of different Radio Access Technologies (RATs), Next Generation Wireless Networks (NGWN) are predicted to be heterogeneous in nature. The coexistence of different RATs requires a need for Common Radio Resource Management (CRRM) to support the provision of Quality of Service (QoS) and the efficient utilization of radio resources. RAT selection algorithms are part of the CRRM algorithms. Simply, their role is to verify if an incoming call will be suitable to fit into a heterogeneous wireless network, and to decide which of the available RATs is most suitable to fit the need of the incoming call and admit it. Guaranteeing the requirements of QoS for all accepted calls and at the same time being able to provide the most efficient utilization of the available radio resources is the goal of RAT selection algorithm. The normal call admission control algorithms are designed for homogeneous wireless networks and they do not provide a solution to fit a heterogeneous wireless network which represents the NGWN. Therefore, there is a need to develop RAT selection algorithm for heterogeneous wireless network. In this paper, we propose an approach for RAT selection which includes receiving different criteria, assessing and making decisions, then selecting the most suitable RAT for incoming calls. A comprehensive survey of different RAT selection algorithms for a heterogeneous wireless network is studied.
Ansari, YHH, Merifield, RS & Sheng, DC 1970, 'A numerical study on the applicability of the piezocone interpretation methods for hydraulic conductivity of clays', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 442-448.
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During the last three decades, attempts have been made to obtain genuine interpretation methods for estimating the fl ow characteristics of fi ne grained soils through piezocone dissipation tests. Interpretation of these dissipation tests is however often based on various simplifying assumptions and has not been extensively calibrated against experimental or numerical results. In this research, piezocone penetration and dissipation tests are modelled numerically using large deformation fi nite element analysis with contact formulation. The effectiveness of the two widely used interpretation methods of Teh & Houlsby (1991) and Sully & Campanella (1994) is studied. It is found that the reliability of these methods is signifi cantly affected by the assumptions adopted. In addition, irrespective of their accuracy, the interpretation methods in the literature are found to be only applicable to normally consolidated to lightly overconsolidated soils.
Askari, M, Li, J & Samali, B 1970, 'Semi-Active LQG Control of Seismically Excited Nonlinear Buildings using Optimal Takagi-Sugeno Inverse Model of MR Dampers', Procedia Engineering, East Asia-Pacific Conference on Structural Engineering and Construction, Elsevier BV, Hong Kong, pp. 2765-2772.
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A novel semi-active control method for a seismically excited nonlinear benchmark building equipped with magnetorheological (MR) dampers is presented and evaluated in this paper. While Linear Quadratic Gaussian (LQG) controller is designed to estimate the optimal control force of a MR damper, the required voltage input for the damper to produce such control force is achieved by a proposed optimal Takagi- Sogeno(T-S) fuzzy inverse model. The proposed T-S fuzzy inverse model of dampers is derived using subtractive clustering, non-dominated sorting genetic algorithm II (NSGAII) and adaptive neuro-fuzzy inference systems (ANFIS). The effectiveness of this strategy is illustrated and verified using simulated response of a 20-storey full-scale nonlinear benchmark building excited by several historical earthquake records. The designed semi-active system is compared with the performances of active control as well as clipped optimal control (COC) systems, which are based on the same nominal controller as is used in this study. The results are discussed based on the evaluation criteria suggested for the benchmark problem by International Association for Structural Control and Monitoring (IASCM) for comparison with other algorithms and demonstrate the superiority of this scheme over other strategies.
Azari, B, Fatahi, B & Khabbaz, H 1970, 'Application of Creep Ratio Concept for Estimating Post-Constriction Settlement of Deep Soft Clay Deposits', ICAGE 2011 - Proceedings of the International Conference on Advances in Geotechnical Engineering, International Conference on Advances in Geotechnical Engineering, Curtin University, Perth, Australia, pp. 127-133.
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Two main different approaches have been previously proposed to predict time dependent behaviour of soft soils. (I) end of primary consolidation is unique although creep starts simultaneously with primary consolidation (Hypothesis A); (II) As creep and primary consolidation commence at the same time and creep is a time dependant phenomenon, then end of primary consolidation cannot be unique (Hypothesis B). In Hypothesis A, soil settlement is divided into two parts: primary consolidation and secondary compression which follows by primary consolidation. In Hypothesis B, soil settlement is estimated based on elasto-viscoplastic constitutive model simulating soil creep and consolidation settlement simultaneously. In this study, details of first approach based on creep ratio ( ) concept is discussed with a worked example to be used by practicing geotechnical engineers.
Cai, C, Wang, Y & Geers, G 1970, 'Quantifying the exact impact of state estimation error on traffic signal control', Proceedings of the 4th ACM SIGSPATIAL International Workshop on Computational Transportation Science, GIS '11: 19th SIGSPATIAL International Conference on Advances in Geographic Information Systems, ACM, pp. 39-44.
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This paper presents a study on quantifying the exact impact of state estimation error on adaptive traffic signal control. The exact impact of state estimation error can be derived using the vertical queuing model and dynamic programming. The vertical queuing model, albeit a simplistic assumption, can be defined unambiguously, and when used to describe the system dynamics in the dynamic programming formulation, enables an exact global optimum to be computed. We further present a model to estimate the impact of state estimation error on multiple cycles of traffic signal operation, which will then be validated by the results obtained from the dynamic programming process based on the vertical queuing model. © 2011 ACM.
Far, H, Fatahi, B & Samali, B 1970, 'Effects of Dynamic Soil-Structure Interaction on Performance Level of Moment Resisting Buildings Resting on Different Types of Soil', Proceedings of the 2011 Pacific Conference on Earthquake Engineering (PCEE), Pacific Conference on Earthquake Engineering (PCEE) - 'Building an Earthquake Resilient Society', New Zealand Society for Earthquake Engineering Inc., New Zealand, pp. 1-8.
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In this study, two structural models comprising five and fifteen storey moment resisting building frames are selected in conjunction with three different soil deposits with shear wave velocity less than 600m/s. The design sections are defined after applying dynamic nonlinear time history analysis based on inelastic design procedure using elastic-perfectly plastic behaviour of structural elements. These frames are modelled and analysed employing Finite Difference approach using FLAC 2D software under two different boundary conditions namely fixed-base (no soil-structure interaction), and considering soil-structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted and the results of inelastic behaviour of the structural models are compared. The results indicate that the inter-storey drifts of the structural models resting on soil types De and Ee (according to the Australian standard) substantially increase when soil-structure interaction is considered for the above mentioned soil types. Performance levels of the structures change from life safe to near collapse when dynamic soil-structure interaction is incorporated. Therefore, the conventional inelastic design procedure excluding SSI is no longer adequate to guarantee the structural safety for the building frames resting on soft soil deposits.
Fatahi, B & Khabbaz, H 1970, 'Enhancement of Ballasted Rail Track Performance Using Geosynthetics', Advances in Pile Foundations, Geosynthetics, Geoinvestigations, and Foundation Failure Analysis and Repairs, GeoHunan International Conference 2011, American Society of Civil Engineers, Hunan, China, pp. 222-230.
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The requirement of keeping a competitive edge against other means of transportation has increased the pressure on the railway industry to improve its efficiency and decrease the maintenance costs. In this paper, several solutions are presented to improve rail track foundations including optimum particle ballast grading and confining pressure as well as stabilising tracks overlying soft soils employing different techniques. This study specifically assesses the influence of shoulder ballast and its combination with geosynthetics to reduce the track settlement due to train load. Two dimensional plane strain finite element model is adopted to simulate the track deformation. Furthermore, the potential use of geosynthetics combined with recycled and blended ballast for reduction of rail displacement is addressed. The different location of geosynthetics in rail track substructure is examined. Rail track performance can be improved by including wider shoulder ballast with geosynthetic layer, and recycled and blended ballast reinforced with geosynthetics can be used during maintenance operation to curtail future track deformation. © 2011 ASCE.
Fatahi, B, Tabatabaiefar, HR & Samali, B 1970, 'Performance Based Assessment of Dynamic Soil-Structure Interaction Effects on Seismic Response of Building Frames', GeoRisk 2011, Georisk 2011, American Society of Civil Engineers, Atlanta, Georgia, USA, pp. 344-351.
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Soil-Structure Interaction (SSI) has progressed rapidly in the second half of 20th century stimulated mainly by requirements of the nuclear power and offshore industries to improve the seismic safety. In this study, a fifteen storey moment resisting building frame is selected in conjunction with three different soil deposits with shear wave velocity less than 600m/s. The design sections are defined after applying dynamic nonlinear time history analysis based on inelastic design procedure using elastic-perfectly plastic behaviour of structural elements. These frames are modelled and analysed employing Finite Difference approach using FLAC 2D software under two different boundary conditions, namely fixed-base (no soil-structure interaction), and considering soil-structure interaction. Fully nonlinear dynamic analyses under the influence of different earthquake records are conducted and the results of inelastic behaviour of the structural model are compared. Variations of the shear modulus ratio with the shear strain are included in the nonlinear dynamic analysis. The results indicate that the inter-storey drifts of the structural model resting on soil types De and Ee (according to the Australian standard) substantially increase when soil-structure interaction is considered for the above mentioned soil types. Performance levels of the structures change from life safe to near collapse when dynamic soil-structure interaction is incorporated. Therefore, the conventional inelastic design procedure excluding SSI is no longer adequate to guarantee the structural safety for the building frames resting on soft soil deposits. Design engineers need to address the effects of dynamic SSI precisely in their design especially for construction projects on soft soils.
Geng, XY, Indraratna, B & Rujikiatkamjorn, C 1970, 'Consolidation of Ground with Partially Penetrated PVDs Combined with Vacuum Preloading', Geo-Frontiers 2011, Geo-Frontiers Congress 2011, American Society of Civil Engineers, pp. 567-575.
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Partially penetrating prefabricated vertical drain (PVDs) with a combined surcharge and vacuum preloading are considered in this paper. The analysis results can be used in cases where the soft soil clay is too deep and not economical to be penetrated to full depth, or the surcharge preloading is too small to justify full penetration of soft clay layer or the vacuum pressure can be lost, which is caused by the permeability of the bottom of the clay for the fully penetrated drain etc. In this model, a virtual vertical drain is assumed to reflect the real three-dimensional seepage in the soil beneath the tip of PVD instead of using the traditional one-dimensional consolidation theory, and at the same time, the well-resistance and the smear zone can be also considered. The vacuum pressure distribution is assumed to be no loss along the drain, whereas a zero pore pressure boundary condition is assumed at the interface between the bottom clay layer and the lower drainage layer. The proposed solutions are then employed to analyze a case history. © ASCE 2011.
Hadi, SJ, Althwaynee, OF, Shafri, HZM & Pradhan, B 1970, 'The use of GPS in mitigating and managing landslides', Proceedings of 10th International Symposium & Exhibition on Geoinformation (ISG 2011) & ISPRS Commission II/5 & II/7 Conference, Malaysia.
Indraratna, B & Nimbalkar, S 1970, 'Implications of ballast breakage on ballasted railway track based on numerical modeling', Computer Methods for Geomechanics: Frontiers and New Applications, International Conference of the International Association for Computer Methods and Advances in Geomechanics, Melbourne, Australia, pp. 1085-1092.
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Large and frequent cyclic train loading from heavy haul and passenger trains often leads to progressive track deterioration. The excessive deformation and degradation of ballast and unacceptable differential settlement of track and/or pumping of underlying soft subgrade soils necessitate frequent and costly track maintenance. A proper understanding of load transfer mechanisms and subsequent deformations in track layers is the key element for safe and economical track design and optimum maintenance procedures. Many simplifi ed analytical and empirical design methods have been used to estimate the settlement and stress-transfer between the track layers. However, these design methods are based on the linear elastic approach, and often only give crude estimates. Given the complexities of the behaviour of the composite track system consisting of rail, sleeper, ballast, sub-ballast and subgrade subject to repeated traffi c loads in a real track environment, the current track design techniques are overly simplifi ed. The track design should also account for the deterioration of ballast due to breakage and subsequent implications on the track deformations. Considering this, an elasto-plastic constitutive model of a composite multi-layer track system is proposed. Constitutive models and material parameters adopted in this numerical model are discussed. A hardening soil model with a non-associative fl ow rule is introduced to accurately simulate the strain-hardening behaviour of ballast. The breakage of ballast observed in large scale triaxial tests is also simulated based on this model. In conjunction, numerical simulations are also performed using a two-dimensional plane-strain fi nite element analysis (PLAXIS) capturing the effects of ballast breakage and track confi ning pressure. The paper also demonstrates the advantages of the proposed elasto-plastic fi nite element simulations when compared to conventional analytical methods used by practitioners that are...
Indraratna, B, Regmi, G, Nghiem, LD & Golab, A 1970, 'Geo-Environmental Approaches for the Remediation of Acid Sulphate Soil in Low-Lying Floodplains', Geo-Frontiers 2011, Geo-Frontiers Congress 2011, American Society of Civil Engineers, pp. 856-865.
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Acidity generated from the oxidation of pyrite and other sulphidic compounds that exist at shallow depths in acid sulphate soils (ASS) presents a challenging environmental problem in coastal Australia. The generated acidic groundwater can adversely impact coastal ecosystems, aquaculture and agriculture. Groundwater manipulation using weirs and modified floodgates in creeks and flood mitigation drains in ASS-affected farmland, which has been practiced for over a decade for preventing pyrite oxidation, is not effective in low-lying floodplains due to the high risk of flooding. In this paper, the authors present an overview of their experience in coastal Australia, a critical evaluation of currently practiced geo-environmental remediation methods as well as a demonstration of a pilot permeable reactive barrier (PRB) to control acidic groundwater pollution. The selection of recycled concrete, a commonly available alkaline waste material, and the systematic investigation of its longevity are highlighted through a series of batch and column experiments. In addition, the improvement of the groundwater quality by a pilot PRB using recycled concrete in ASS terrain within the Shoalhaven region of NSW, Australia will be elucidated based on field data collected over the last 3.5 years. © ASCE 2011.
Indraratna, B, Rujikiatkamjorn, C & Jing, N 1970, 'Cyclic Behaviour of Soft Soil Subgrade Improved by Prefabricated Vertical Drains', DEFORMATION CHARACTERISTICS OF GEOMATERIALS, PTS 1 AND 2, 5th International Symposium on Deformation Characteristics of Geomaterials (IS), IOS PRESS, SOUTH KOREA, Seoul, pp. 559-564.
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Indraratna, B, Rujikiatkamjorn, C, Vinod, JS & Nimbalkar, S 1970, 'PHYSICAL AND CHEMICAL GROUND IMPROVEMENT FOR SUSTAINABLE TRANSPORTATION INFRASTRUCTURE UNDER CYCLIC LOADS', Geotechnical Engineering for Disaster Mitigation and Rehabilitation and Highway Engineering 2011, Proceedings of the 3rd and 5th International Conference, WORLD SCIENTIFIC, Semarang, INDONESIA, pp. 140-156.
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iti Nur Afiqah Aman, ZAL 1970, 'Landslide hazard assessment using LiDAR and spatially related conditioning factors', Proceedings of 10th International Symposium & Exhibition on Geoinformation 2011 (ISG 2011), 27-19 September 2011. Shah Alam, Malaysia.
Lane, C, Gal, Y, Browne, M, Short, A, Strauss, D, Tomlinson, R, Jackson, K, Tan, C & Blumenstein, M 1970, 'A new technique for measuring breaking wave dynamics, heights and periods', 20th Australasian Coastal and Ocean Engineering Conference 2011 and the 13th Australasian Port and Harbour Conference 2011, COASTS and PORTS 2011, pp. 277-280.
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A new system for measuring breakzone dynamics, breaking wave heights and wave periods across the surfzone from a digital video sequence is presented. The WavePack system was tested using a set of 39 video files covering a range of wave heights and conditions on different days. The relatively low percentage of rejected wave counts supports the flexibility of the wave height processing algorithm to perform in the highly variable wave conditions. The processed wave heights correlated highly with the independent sources of wave height available having a correlation of 0.86 to manual counts and 0.85 with NOAA WW3 significant wave height. It was found that the WavePack system can provide a low cost, robust, reliable and accurate system for measuring continuous wave height from a low elevation video camera aimed at the target beach under a wide range of wave conditions.
Le, T, Fatahi, B & Khabbaz, H 1970, 'Soil Creep Mechanisms and Inducing Factors', ICAGE 2011 - Proceedings of the International Conference on Advances in Geotechnical Engineering, International Conference on Advances in Geotechnical Engineering, Curtin University, Perth, Australia, pp. 241-246.
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Soft soils have been utilised intensively for urbanisation and civil infrastructural development due to the scarcity of proper soils for construction. Soft soils themselves exhibit many engineering problems, such as large settlement which occurs in long time after construction. There are a large number of studies carried out to analyze that time dependent behaviour of soft soils, resulting in the variety of theories and models. The mechanism of creep deformation is the background to propose a model for predicting the long term settlement. However, there has been no unique explanation for the behavior of soils, leading to different theories of settlement analysis and prediction. There exist two main hypotheses for settlement calculation, Hypotheses A and B, distinguished based on different elucidation about creep mechanisms. From the existing research studies, this paper aims to discuss five mechanisms of creep including (i) the breakdown of interparticle bonds, (ii) the jumping of bonds of molecules, (iii) sliding movement among particles, (iv) the water drainage in double pore system, and (v) the structural viscosity. In this study, according to the explanation of creep mechanisms, the difference of the two hypotheses will be provided. This paper also suggests a creep mechanism based on the combinations of the explained mechanisms.
Li, Y, Li, J & Samali, B 1970, 'Design of new generation magnetorheological pins', Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press/Balkema, Melbourne, Australia, pp. 807-812.
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Recently, research and development of smart materials and structures for civil engineering applications have attracted increasing attentions from researchers around theworld. Smart devices can be incorporated into civil structures as smart structural members with intelligent and controllable capacities for optimally detecting and reacting to the internal and external changes.Within the smart devices, magnetorheological (MR) based devices are one of the most promising smart devices to be considered for civil structures. This paper presents a novel design of a new-generation MR pin joint with high-torque capacity. An innovative design and analysis of MR pin with radial slots at the surface of the rotary plate is proposed. Theoretical modelling is undertaken based on the material, mechanical and magnetic analyses. Parametric analysis is conducted to optimise the shape, width and depth of the slots to best accommodate the design objectives. © 2011 Taylor & Francis Group, London.
Li, Z, Xu, J, Wang, Y, Geers, G & Yang, J 1970, 'Saliency detection based on proto-objects and topic model', 2011 IEEE Workshop on Applications of Computer Vision (WACV), 2011 IEEE Workshop on Applications of Computer Vision (WACV), IEEE, pp. 125-131.
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This paper proposes a novel computational framework for saliency detection, which integrates the saliency map computation and proto-objects detection. The proto-objects are detected based on the saliency map using latent topic model. The detected proto-objects are then utilized to improve the saliency map computation. Extensive experiments are performed on two publicly available datasets. The experimental results show that the proposed framework outperforms the state-of-art methods. © 2010 IEEE.
Liwicki, M, Malik, MI, Heuvel, CEVD, Chen, X, Berger, C, Stoel, R, Blumenstein, M & Found, B 1970, 'Signature Verification Competition for Online and Offline Skilled Forgeries (SigComp2011)', 2011 International Conference on Document Analysis and Recognition, 2011 International Conference on Document Analysis and Recognition (ICDAR), IEEE, Beijing, China, pp. 1480-1484.
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The Netherlands Forensic Institute and the Institute for Forensic Science in Shanghai are in search of a signature verification system that can be implemented in forensic casework and research to objectify results. We want to bridge the gap between recent technological developments and forensic casework. In collaboration with the German Research Center for Artificial Intelligence we have organized a signature verification competition on datasets with two scripts (Dutch and Chinese) in which we asked to compare questioned signatures against a set of reference signatures. We have received 12 systems from 5 institutes and performed experiments on online and offline Dutch and Chinese signatures. For evaluation, we applied methods used by Forensic Handwriting Examiners (FHEs) to assess the value of the evidence, i.e., we took the likelihood ratios more into account than in previous competitions. The data set was quite challenging and the results are very interesting. © 2011 IEEE.
Movassaghi, S, Abolhasan, M & Lipman, J 1970, 'Hierarchical Collision-free Addressing Protocol(HCAP) for Body Area Networks', 2011 IEEE Conference on Computer Communications Workshops (INFOCOM WKSHPS), IEEE INFOCOM 2011 - IEEE Conference on Computer Communications Workshops, IEEE, Shanghai, China, pp. 543-548.
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In Body Area Networks (BANs) the addressing scheme used to address nodes is fundamental to the effective operation of a BAN. This paper proposes a novel BAN addressing scheme called Hierarchical Collision-free Addressing Protocol (HCAP). Proposed scheme is collision free, reduces power consumption and tackles the address wastage problem. Two important scenarios (random location and fixed location) are defined and studied. Through a series of simulation results we show the efficiency and usability of the proposed scheme in Body Area Networks. © 2011 IEEE.
Movassaghi, S, Abolhasan, M, Lipman, J & IEEE 1970, 'Optimized Prophet Address Allocation (OPAA) for Body Area Networks', 2011 7TH INTERNATIONAL WIRELESS COMMUNICATIONS AND MOBILE COMPUTING CONFERENCE (IWCMC), ACM International Wireless Communications and Mobile Computing Conference, IEEE, Istanbul, Turkey, pp. 2098-2102.
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Each node in a Body Area Network (BAN) needs to be assigned with a free IP address before it may participate in any sort of communication. This paper evaluates the performance of an IP address allocation scheme, namely Prophet allocation to be used for BANs. This allocation scheme is a fully decentralized addressing scheme which is applicable to BANs as it provides low latency, low communication overhead and low complexity. Relative theoretical analysis and simulation experiments have also been conducted to demonstrate its benefits which also represent the reason for the choice of this allocation scheme. It also solves the issues related to network partition and merger efficiently. © 2011 IEEE.
Nazem, M, Kardani, M, Carter, JP & Sheng, D 1970, 'Application of h-adaptive fe method for dynamic analysis of geotechnical problems', Computational Geomechanics, COMGEO II - Proceedings of the 2nd International Symposium on Computational Geomechanics, pp. 490-495.
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h-adaptive finite element procedures automatically change and optimise the density of a finite element mesh in a region to obtain a more accurate solution or to avoid mesh distortion in large deformation problems. These goals are usually achieved by generating a new finite element mesh over the integration domain based upon an error estimation or a distortion criterion. In this study an h-adaptive finite element method is suggested to solve dynamic problems of geomechanics involving large deformations. This hadaptive technique is based upon an implicit Updated-Lagrangian method, in which mesh distortion and entanglement of elements are intrinsic pitfalls. A summary of the h-adaptive technique is presented by introducing its important aspects such as error estimation, remapping of time-dependent state variables, and dynamic equilibrium checks. The efficiency and robustness of the method is demonstrated by considering numerical examples characterised by inertia forces and large deformations.
Nguyen, V, Blumenstein, M & IEEE 1970, 'An Application of the 2D Gaussian Filter for Enhancing Feature Extraction in Off-line Signature Verification', 11TH INTERNATIONAL CONFERENCE ON DOCUMENT ANALYSIS AND RECOGNITION (ICDAR 2011), International Conference on Document Analysis and Recognition (ICDAR), IEEE, Beijing, China, pp. 339-343.
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Similar to many other pattern recognition problems, feature extraction contributes significantly to the overall performance of an off-line signature verification system. To be successful, a feature extraction technique must be tolerant to different types of variation whilst preserving essential information of input patterns. In this paper, we describe a grid-based feature extraction technique that utilises directional information extracted from the signature contour, i.e. the chain code histogram. Our experimental results for signature verification indicated that, by applying a suitable 2D Gaussian filter on the matrices containing the chain code histograms, an average error rate (AER) of 13.90% can be obtained whilst maintaining the false acceptance rate (FAR) for random forgeries as low as 0.02%. These figures are comparable or better than those reported by other state of the art feature extraction techniques such as the Modified Direction Feature (MDF) and the Gradient feature. © 2011 IEEE.
Oberst, S & Lai, JCS 1970, 'Nonlinear friction coupling in disc brake squeal', 18th International Congress on Sound and Vibration 2011, ICSV 2011, International Congress on Sound and Vibration, International Institute of Acoustics & Vibration, Rio de Janeiro, Brazil, pp. 1748-1755.
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Friction-induced noise, such as disc brake squeal as a research area of practical importance to the automotive industry, has been investigated for many years. In recent years research focus was on dynamic instabilities such as mode coupling as the most prominent squeal mechanism, rather than on physical or geometric instabilities as trigger mechanisms. However, many trigger mechanisms such as contact and friction nonlinearity are still poorly understood. In brake squeal analysis, pad-dynamics is poorly understood and in-plane radial and out-of-plane pad vibrations are often neglected as most research has been directed towards understanding the dynamics of the rotor as the main structure radiating sound. However, recent research has shown that transient radial in-plane vibrations of the pad might be a novel squeal mechanism. In this study, the transient nature of these radial in-plane vibrations and their influence on the overall vibration and dynamic behaviour is investigated. For this purpose a sinusoidally driven in-plane sliding of a friction-coupled 2-dof oscillator (in the form of a slider over a moving belt) is formulated based on the most stable configuration of a 1-dof dry friction oscillator with continuous/ locking contact using a friction law with constant/static-kinetic/velocitydependent friction coefficient. It is found that due to nonlinear friction-coupling, steady-state in-plane radial vibrations induce a broadband spectrum in the overall dynamics of the friction oscillator with slightly fractal POINCARE section for a small belt's angle. The results indicate the importance of in-plane pad-vibrations as a possible trigger squeal mechanism. Copyright © (2011) by the International Institute of Acoustics & Vibration.
Pal, S, Alireza, A, Pal, U & Blumenstein, M 1970, 'Off-line Signature Identification Using Background and Foreground Information', 2011 International Conference on Digital Image Computing: Techniques and Applications, 2011 International Conference on Digital Image Computing: Techniques and Applications (DICTA), IEEE, Noosa, QLD, Australia, pp. 672-677.
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Biometric systems play an important role in the field of information security as they are extremely required for user authentication. Automatic signature recognition and verification is one of the biometric techniques, which is currently receiving renewed interest and is only one of several techniques used to verify the identities of individuals. Signatures provide a secure means for confirmation and authorization in legal documents. So nowadays, signature identification and verification becomes an essential component in automating the rapid processing of documents containing embedded signatures. In this paper, a technique for a bi-script off-line signature identification system is proposed. In the proposed signature identification system, the signatures of English and Bengali (Bangla) are considered for the identification process. Different features such as under sampled bitmaps, modified chain-code direction features and gradient features computed from both background and foreground components are employed for this purpose. Support Vector Machines (SVMs) and Nearest Neighbour (NN) techniques are considered as classifiers for signature identification in the proposed system. A database of 1554 English signatures and 1092 Bengali signatures are used to generate the experimental results. Various results based on different features are calculated and analysed. The highest accuracies of 99.41%, 98.45%; and 97.75% are obtained based on the modified chain-code direction, under-sampled bitmaps and gradient features respectively using 1800 (1100 English+700 Bengali) samples for training and 846 (454 English+392 Bengali) samples for testing. © 2011 IEEE.
Pal, S, Blumenstein, M & Pal, U 1970, 'Non-english and non-latin signature verification systems: A survey', CEUR Workshop Proceedings, International Workshop on Automated Forensic Handwriting Analysis, CEUR, Beijing, China, pp. 1-5.
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Signatures continue to be an important biometric because they remain widely used as a means of personal verification and therefore an automatic verification system is needed. Manual signature-based authentication of a large number of documents is a difficult and time consuming task. Consequently for many years, in the field of protected communication and financial applications, we have observed an explosive growth in biometric personal authentication systems that are closely connected with measurable unique physical characteristics (e.g. hand geometry, iris scan, finger prints or DNA) or behavioural features. Substantial research has been undertaken in the field of signature verification involving English signatures, but to the best of our knowledge, very few works have considered non-English signatures such as Chinese, Japanese, Arabic etc. In order to convey the state-of-the-art in the field to researchers, in this paper we present a survey of non-English and non-Latin signature verification systems.
Pal, S, Blumenstein, M & Pal, U 1970, 'Off-line signature verification systems', Proceedings of the International Conference & Workshop on Emerging Trends in Technology - ICWET '11, the International Conference & Workshop, ACM Press, Mumbai, Maharashtra, India, pp. 652-657.
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Signatures are extensively used as a means of personal verification. Manual signature-based authentication of a large number of documents is a very difficult and time consuming task. Consequently for many years, in the field of protected communication and financial applications, we have observed an explosive growth in biometric personal authentication systems that are closely connected with measurable physical unique characteristics (hand geometry, iris scan, finger prints or DNA) or behavioural features. Human signatures provide secure means for confirmation and authorization in legal documents. So nowadays, automatic signature verification becomes an essential component. In order to convey the state-of-the-art in the field to researchers, in this paper we present a survey of off-line signature verification systems. Copyright © 2011 ACM.
Parsa Pajouh, A, Fatahi, B & Khabbaz, H 1970, 'Numerical Back Analysis of Smear Zone Properties for Vertical Drain Assisted Preloading in Soft Soils', ICAGE 2011 - Proceedings of the International Conference on Advances in Geotechnical Engineering, International Conference on Advances in Geotechnical Engineering, Curtin University, Perth, Australia, pp. 561-566.
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Installation of prefabricated vertical drains (PVDs) using a mandrel causes disturbance of the clay surrounding the drain, resulting in a smear zone of reduced permeability, which adversely affects consolidation process. There are two important parameters to characterize the smear effects, namely, the smear zone diameter and the permeability ratio. In this study, FLAC finites difference software has been employed to investigate the effects of smear zone characteristics on required time for preloading. The results of a fully instrumented trial embankment in Sunshine Motorway, Queensland, have been used to verify the model, and parametric studies have been conducted on the predicted ground settlement and pore water pressure. According to the results, changes in smear zone parameters can significantly affect the consolidation period. It is observed that the characteristics of smear zone namely size and permeability have a substantial impact on the preloading design to achieve a certain soil strength and stiffness satisfying both bearing capacity and settlement design criteria.
Pradhan, B 1970, 'Ethics in writing research articles in Research Universities (RU) in Malaysia', Global Conference on Ethics in Science & Technology, The University of Santo Tomas, Manila, Philippines.
Pradhan, B 1970, 'The role of Geoinformation technology for Geohazards Management: Examples from South East Asia', 5th SASTECH: 5th Symposium on Advances in Science & Technology, Khavaran Higher Education Institute Fallahi Ghasem.
Pradhan, B 1970, 'Trends in Advanced Spatial Modelling Techniques for Geohazard Management', 10th International Symposium & Exhibition on Geoinformation 2011 (ISG 2011), ISG 2011.
Pradhan, B 1970, 'Use of Remote Sensing & GIS for Natural Hazard Detection, Modelling & Mitigation', The International Conference on Natural Sciences, Alexander Von Humboldt Foundation, Germany and Ma, pp. Invited-Speaker.
Rafiei, A, Abolhasan, M, Franklin, D & Safaei, F 1970, 'Boundary Node Selection Algorithms in WSNs', 2011 IEEE 36TH CONFERENCE ON LOCAL COMPUTER NETWORKS (LCN), IEEE Conference on Local Computer Networks, IEEE, Bonn, Germany, pp. 251-254.
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Physical damage and/or node power exhaustion may lead to coverage holes in WSNs. Coverage holes can be directly detected by certain proximate nodes known as boundary nodes (B-nodes). Due to the sensor nodes' redundant deployment and autonomous fault detection, holes are surrounded by a margin of B-nodes (MB-nodes). If all B-nodes in the margin take part in the hole recovery processes, either by increasing their transmission power or by relocating towards region of interest (ROI), the probability of collision, interference, disconnection, and isolation may increase affecting the rest of the network's performance and QoS. Thus, distributed boundary node selection algorithms (BNS-Algorithms) are proposed to address these issues. BNS-algorithms allow B-nodes to self-select based on available 1-hop information extracted from nodes' simple geometrical and statistical features. Our results show that the performance of the proposed distributed BNS-algorithms approaches that of their centralized counterparts. © 2011 IEEE.
Rujikiatkamjorn, C, Indraratna, B & Aljorany, A 1970, 'Consolidation by vertical drain beneath a circular embankment using analytical and numerical modelling', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 1000-1005.
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When prefabricated vertical drains (PVDs) are installed beneath circular embankment (i.e. circular oil tanks or silos), the system of vertical drains can be replaced by axisymmetric concentric rings with equivalent drain walls. A value for the equivalent coeffi cient of soil permeability must be obtained to provide the same degree of consolidation. A rigorous solution for PVDs installed under circular embankment is proposed and verifi ed by comparing its results with conventional unit cell model. The model is then validated via the consolidation process by vertical drains at the Ska-Edeby circular test embankment (Area II). The calculated values of settlement, lateral displacement and excess pore water pressure provide good agreement with the fi eld measurements.
Saleh, A, Li, J & Lucas, J 1970, 'Internet-hosted assessment system for effective teaching and enhanced learning for engineering subjects', Proceedings of the 22nd Annual Conference for the Australasian Association for Engineering Education (AAEE2011) - Developing Engineers for Social Justice: Community Involvement, Ethics & Sustainability, AAEE - Annual Conference of Australasian Association for Engineering Education, Engineers Australia, Fremantle, WA, pp. 505-509.
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Despite of their popularity, online Learning Management Systems suffer serious limitations as a reliable and effective assessment tool in their implementation for engineering education, partly due to their demand for equation manipulation and multiple stage problem solving. An innovative spreadsheet based assessment tool (e-Task) which is designed to overcome such shortcoming and provides effective teaching and enhanced learning for engineering subjects has been proposed by the authors. The tool was developed for both formative and summative assessments with a capability to automatically collect not only results but also feedback from students on their perceived learning. Building on the previous work, this paper presents a further development by introducing a new deployment concept of the e-Task through internet-hosting of the system in order to enable effective teaching and enhanced learning of engineering subjects. The proposed internet-hosted assessment system (e-Task) integrates state-of-the-art cloud computing technology by incorporating a spreadsheet-like environment that can accommodate a wider range of users and course developers as well as enables easier expansion of the system in the future. It greatly enhances the fundamental concepts proposed in the original e-Taks by offering better accessibility, flexibility and controllability. It obviates any need of a specific software or hardware for the operational platform and requires only Internet access for its operation. Features of the Internet hosted e-Task include: the ability to access it by various Internet browsers, embedding learning and diagnostic feedback, individualised data sets for each students and automated marking & feedback.
Samali, B, Fatahi, B & Tabatabaiefar, HR 1970, 'Seismic behaviour of concrete moment resisting buildings on soft soil considering soil-structure interaction', Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press/Balkema, Melbourne, Australia, pp. 407-412.
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In this study, the effects of soil-structure interaction (SSI) on the seismic behaviour of reinforced concrete moment resisting building frames are studied using finite difference method. Two types of mid-rise structures, consisting of 5 and 15 stories on soft soil, are selected and analysed. The above mentioned frames are analysed under two different boundary conditions: (i) fixed-base (no soil-structure interaction), and (ii) considering soil-structure interaction. To model soil-structure interaction, the soil medium considering soil's non-linear damping and plasticity with interface elements between soil and structure is included. The results of the analyses in terms of structural forces and lateral displacements for the above mentioned boundary conditions for different earthquakes are compared. It is observed that lateral deflections and drifts of the structures increase when SSI is included. © 2011 Taylor & Francis Group, London.
Samali, B, Li, J, Crews, K & Choi, FC 1970, 'Damage evaluation of a repaired timber beam using modal-based method', Incorporating Sustainable Practice in Mechanics of Structures and Materials - Proceedings of the 21st Australian Conference on the Mechanics of Structures and Materials, Australasian Conference on the Mechanics of Structures and Materials, CRC Press/Balkema, Melbourne, Australia, pp. 751-755.
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For bridge structures, global damage evaluation and structural health monitoring using modal based damage identification methods have dominated recent worldwide research. However, to date there are few works reported on the effectiveness of the methods to evaluate the new conditions after the damaged structures have been repaired. In this paper, a modal based damage identification method for localisation of damage in a timber beam, utilising modal data from before and after damage as well as after repair, is presented based on experimental results. The method employs modal parameters that monitor changes in modal strain energy of damaged and repaired beams with respect to the undamaged one. Experimental modal analysis is used in the experimental work to acquire the modal parameters required by the method. The study aims to investigate the capability and limitations of the proposed method for identifying locations of damage in damaged and repaired timber structures. © 2011 Taylor & Francis Group, London.
Sheng, D 1970, 'Constitutive modelling of unsaturated soils: Discussion of fundamental principles', Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils, pp. 91-112.
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An unsaturated soil is not a special type of soil, rather a state of the soil. All soils can be partially saturated with water. Therefore, constitutive models for soils should ideally represent the soil behaviour over entire ranges of possible pore pressure and stress values and allow arbitrary stress and hydraulic paths within these ranges. This paper attempts to present an overview of constitutive modelling for unsaturated soils. In particular, it focuses on the fundamental principles that govern the volume change, shear strength, yield surfaces, water retention and hydro-mechanical coupling. Alternative forms of these principles are critically examined in terms of their advantages and disadvantages. The paper also presents a short summary of implementing constitutive models into the finite element method. © 2011 Taylor & Francis Group, London.
Sheng, D & Zhou, AN 1970, 'Hydro-mechanical coupling for unsaturated soils', Unsaturated Soils - Proceedings of the 5th International Conference on Unsaturated Soils, pp. 957-963.
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This paper presents an alternative method to couple the hydraulic component with the mechanical component in a constitutive model for unsaturated soils. Some pioneering work on hydromechanical coupling is first reviewed. Generalised constitutive relations on coupled hydro-mechanical behaviour are then introduced. These generalised constitutive relations are incorporated into an existing model, the SFG model, to predict the effects of specific volume on the saturation-suction relationship. The coupled model is validated against experimental data for different soils. © 2011 Taylor & Francis Group, London.
Sheng, D, Augarde, CE & Abbo, AJ 1970, 'A fast algorithm for finding the first intersection with a non-convex yield surface', Computational Geomechanics, COMGEO II - Proceedings of the 2nd International Symposium on Computational Geomechanics, pp. 496-507.
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A major task in the numerical modeling of soils using complex elasto-plastic models is stress updating. This paper proposes a fast and robust numerical algorithm for locating the first intersection between a non-convex yield surface and an elastic trial stress path. The intersection problem is cast into a problem of finding the smallest positive root of a nonlinear function. Such a function may have multiple roots within the interval of interest. The method is based on the Modified Steffensen method, with important modifications to address the issues arising from the non-convexity. Numerical examples demonstrate that the proposed M2 Steffensen method is indeed computationally efficient and robust.
Shrestha, B, Khabbaz, H & Fatahi, B 1970, 'PERFORMANCE ANALYSIS OF REINFORCED SOIL FOUNDATION STRUCTURES WITH VERTICAL REINFORCEMENT', GEOTECHNICAL ENGINEERING FOR DISASTER MITIGATION AND REHABILITATION 2011/GEOTECHNICAL AND HIGHWAY ENGINEERING - PRACTICAL APPLICATIONS, CHALLENGES AND OPPORTUNITIES, 3rd Int Conf on Geotechnical Engn for Disaster Mitigation and Rehabilitation/5th Int Conf on Geotechnical and Highway Engn - Practical Applications, Challenges and Opportunities, WORLD SCIENTIFIC PUBL CO PTE LTD, Semarang, INDONESIA, pp. 443-448.
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This study examines the performance of geosynthetic reinforced wall inserting vertical elements in conjunction with conventional horizontal reinforcements. In this system, similar to normal reinforcement, the selected granular material is compacted over the horizontal reinforcement up to the designed height and then another layer of horizontal reinforcement is laid down. Numerical investigations have been carried out using finite element software, PLAXIS. Geosynthetic reinforced soil foundation performance and its characteristics have been simulated with and without vertical reinforcement under static and dynamic loads. Numerical results show that the total settlement decreases by inserting inclined reinforcement in both static and dynamic loading in general, and particularly under seismic loading. A new bearing capacity formula incorporating the contribution of both vertical and horizontal reinforcements is also introduced based on the previously published studies and the outputs of this numerical simulation.
Shrestha, B, Khabbaz, H & Fatahi, B 1970, 'Performance Comparison of Vertical-Horizontal with Conventional Reinforced Soil Walls Using Numerical Modelling', PROCEEDINGS OF THE 15TH AFRICAN REGIONAL CONFERENCE ON SOIL MECHANICS AND GEOTECHNICAL ENGINEERING: RESOURCE AND INFRASTRUCTURE GEOTECHNICS IN AFRICA: PUTTING THEORY INTO PRACTICE, 15th African Regional Conference on Soil Mechanics and Geotechnical Engineering (ARCSMGE), IOS PRESS, Maputo, MOZAMBIQUE, pp. 237-242.
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Conventional reinforced soil walls have demonstrated acceptable performance during earthquake occurrences. Nevertheless, there is still some potential for enhancing the performance of these walls without increasing the cost significantly. This paper presents an overview on the application of vertical components to the reinforced soil in addition to the horizontal reinforcement. The performance of conventional and the modified reinforced soil walls are evaluated and compared to each other. In this study, a series of 2D models is carried out using PLAXTS, finite element software, to investigate behaviour of these walls. The performance of reinforced walls is evaluated under the seismic loads of Kobe earthquake. The results indicate that the proposed wall with vertical reinforcement has superior performance compared with the conventional method and can reduce the risk of failure during earthquakes.
Sloan, SW, Abbo, AJ & Sheng, DC 1970, 'Accelerated convergence of Newton-Raphson method using a least squares approximation to the consistent tangent matrix', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 15-20.
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Consistent tangent formulations have the highly desirable property of providing quadratic convergence when Newton-Raphson iteration is used to solve the global stiffness equations. The implementation of these formulations, however, is not straightforward as they require the use of an implicit stress integration scheme in order to form the consistent stiffness matrix. These integration schemes are not well suited to adaptive sub-stepping (which is extremely effective for handling the complex constitutive relations that are typical for geomaterials) and are prone to non-convergence unless very small load steps are used. This paper presents a new technique for accelerating the convergence of Newton-Raphson iteration that is based on the consistent tangent approach with a least squares approximation to the plastic multiplier. The signifi cance of the method is that it allows a quasi-consistent tangent formulation to be used in conjunction with explicit stress integration schemes. Although the procedure does not provide quadratic convergence, it does accelerate the Newton-Raphson iteration process dramatically and is very robust.
Su, LJ, Indraratna, B & Rujikiatkamjorn, C 1970, 'Non-destructive assessment of rail track condition using ground penetrating radar', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 478-482.
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Ground penetrating radar (GPR) can be used to locate interfaces and underground utilities, and evaluate ballast fouling conditions, moisture content and subgrade conditions depending on frequencies of antenna and data processing techniques. In Australia, trial testing on railway sections has been conducted by the railway industry. However, in these trials, testing is only conducted on actual tracks where the relationship between track conditions and the GPR response has not yet been established. In this paper, a full scale model rail track designed and constructed at the University of Wollongong is used to investigate factors that infl uence the GPR data quality, such as the GPR antenna frequency, the degree and moisture content of ballast fouling and sampling frequency. GPR testing was conducted using ground coupled antennas with different frequencies. Comparisons are made to identify the suitable frequency applicable for the assessment of track condition which will be used subsequently to improve the accuracy of site investigations.
Thakur, PK, Vinod, JS & Indraratna, B 1970, 'The role of particle breakage on the shear behaviour of coarse granular materials: A micromechanical investigation', Geomechanics and Geotechnics: From Micro to Macro - Proceedings of the International Symposium on Geomechanics and Geotechnics: From Micro to Macro, IS-Shanghai 2010, International Symposium on Geomechanics and Geotechnics - From Micro to Macro, CRC PRESS-TAYLOR & FRANCIS GROUP, Shanghai, PEOPLES R CHINA, pp. 585-589.
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In this investigation, a DEM based computer program Particle Flow Code in Two Dimension (PFC 2D) has been used to study the cyclic behavior of ballast particles. Angular ballast particles were modeled as clusters of bonded circular particles and degradation of the bonds within a cluster was considered to represent particle breakage. The results of DEM simulations captured the ballast behaviour under cyclic loading in accordance with the experimental observations. Furthermore, a relationship has been proposed between, micromechanical parameter, particle displacement vectors and number of bond breakage. © 2011 Taylor & Francis Group.
Xu, J, Wang, Y, Wang, W, Yang, J & Li, Z 1970, 'Unsupervised Moving Object Detection with On-line Generalized Hough Transform', COMPUTER VISION - ACCV 2010, PT III, 10th Asian Conference on Computer Vision, Springer Berlin Heidelberg, Queenstown, NEW ZEALAND, pp. 145-156.
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Xu, J, Ye, G, Wang, Y, Wang, W & Yang, J 1970, 'Online Learning for PLSA-Based Visual Recognition', COMPUTER VISION - ACCV 2010, PT II, 10th Asian Conference on Computer Vision (ACCV), Springer Berlin Heidelberg, Queenstown, NEW ZEALAND, pp. 95-108.
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Yang, C, Sheng, DC & Carter, JP 1970, 'Numerical modelling of hydraulic hysteresis in unsaturated soil covers', Computer Methods for Geomechanics: Frontiers and New Applications, pp. 741-746.
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This paper aims to study the effect of hydraulic hysteresis on seepage in unsaturated soils. A hysteretic water retention model is incorporated into the Richards equation to describe water fl ow in unsaturated soils. A linear scanning curve is used to describe the hydraulic behaviour within the main hysteretic loop of the water retention curves. The proposed approach is implemented into a fi nite difference code, and is then used to analyse seepage in soil covers on wastes. An infi ltration test on a two-layered soil column is simulated with the proposed hysteretic model. Results show that hydraulic hysteresis plays a crucial role in the seepage analysis of unsaturated soils subjected to cyclic drying and wetting. The hysteretic model is suggested for use in the design and evaluation of the hydraulic performance of soil covers.
Yang, J, Wang, Y, Sowmya, A, Li, Z, Zhang, B & Xu, J 1970, 'Feature fusion for vehicle detection and tracking with low-angle cameras', 2011 IEEE Workshop on Applications of Computer Vision (WACV), 2011 IEEE Workshop on Applications of Computer Vision (WACV), IEEE, pp. 382-388.
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In this paper, we address the problem of vehicle detection and tracking with low-angle cameras by combining windshield detection and feature points clustering, effectively fusing several primitive image features such as color, edge and interest point. By exploring various heterogenous features and multiple vehicle models, we achieve at least two improvements over the existing methods: higher detection accuracy and the ability to distinguish different vehicle types. Our experiments on real-world traffic video sequences demonstrate the benefits of feature fusion and the improved performance. © 2010 IEEE.
Yang, J, Wang, Y, Sowmya, A, Xu, J, Li, Z & Zhang, B 1970, 'Spatial-Temporal Affinity Propagation for Feature Clustering with Application to Traffic Video Analysis', COMPUTER VISION - ACCV 2010, PT II, 10th Asian Conference on Computer Vision (ACCV), Springer Berlin Heidelberg, Queenstown, NEW ZEALAND, pp. 606-618.
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Yasser Ghobadi, Saeid.Pirasteh 1970, 'Wetland change detection using multi-temporal Landsat imagery: Hor-Al- Azim wetland, Iran', 39th COSPAR Scientific Assembly, COSPAR Scientific Assembly.
Joshi, PK & Singh, TP 2011, 'Geoinformatics for climate change studies', The Energy and Resources Institute (TERI).
Mat, RC, Shariff, ARM, Mahmud, AR, Pradhan, B & Rahim, MSM 2011, 'A New Four Tier Framework for Online Application of 3D Visualization'.
Pradhan, B 2011, 'Geoinformation techniques in disaster management Advances in geoinformation based methods and modeling approaches for geohazards management', LAP LAMBERT Academic Publishing GmbH & Co. KG, Saarbrücken, Germany.
