Brown, LD, Ray, AS & Thomas, PS 2004, 'Elemental analysis of Australian amorphous banded opals by laser-ablation ICP-MS', NEUES JAHRBUCH FUR MINERALOGIE-MONATSHEFTE, vol. 9, no. 9, pp. 411-424.
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Brown, LD, Ray, AS & Thomas, PS 2004, 'Elemental analysis of Australian amorphous banded opals by laser-ablation ICP-MS', Neues Jahrbuch fur Mineralogie, Monatshefte, no. 9, pp. 411-424.
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Several banded Australian opal-AG samples were analysed by laser ablation ICP-MS. The banded opals studied contained darker-coloured black or grey bands adjacent to lighter-coloured white or clear bands. The elemental distribution between bands indicated that darker-coloured bands contained significantly higher concentrations of transition elements (Ti, Co, V, Ni, Cu, Zn and Y) and rare-earth elements (La, Ce) than lighter-coloured bands. A solution depletion model, involving the charge-neutralisation of silica collóids by highly-charged transition metal cations, is proposed to explain these results. Irrespective of the origin of the opal, the distribution of trace elements for the white, translucent and play of colour opal bands was observed to be similar. This similarity was consistent with the proposed model. © 2004 E. Schweizerbart'sche Verlagsbuchhandlung, D-70176 Stuttgart.
Ding, G & Langston, C 2004, 'Multiple Criteria Sustainability Modelling: Case Study on School Buildings', International Journal of Construction Management, vol. 4, no. 2, pp. 13-26.
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Ha, QP & Rye, DC 2004, 'A control architecture for robotic excavation in construction', COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, vol. 19, no. 1, pp. 28-41.
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Ha, QP & Trinh, H 2004, 'Observer-based control of multi-agent systems under decentralized information', INTERNATIONAL JOURNAL OF SYSTEMS SCIENCE, vol. 35, no. 12, pp. 719-728.
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This paper addresses the problem of decentralized implementation of a global state feedback controller for multi-agent systems. The system is assumed to be under the constraint of a complete decentralized information structure. The decentralization of the control task is achieved through the construction of low-order decentralized functional observers with the purpose of generating the required corresponding control signal for each local control station. A design procedure is developed for obtaining an approximate solution to the design of the observers. Stability analysis is provided for the global system using the proposed observer-based approach. A numerical example is given to illustrate the design procedure and cases when the observers' order increases from the lowest value.
Ha, QP & Trinh, H 2004, 'State and input simultaneous estimation for a class of nonlinear systems', AUTOMATICA, vol. 40, no. 10, pp. 1779-1785.
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This paper addresses the problem of estimating simultaneously the state and input of a class of nonlinear systems. Here, the systems nonlinear part comprises a Lipschitz nonlinear function with respect to the state and input, and a state-dependent unknown function including additive disturbance as well as uncertain/nonlinear/time-varying terms. Upon satisfying some conditions, the observer design problem can be solved via a Riccati inequality or a LMI-based technique with asymptotic estimation guaranteed. A numerical example is included for illustration. © 2004 Elsevier Ltd. All rights reserved.
Indraratna, B, Bamunawita, C & Khabbaz, H 2004, 'Numerical modeling of vacuum preloading and field applications', CANADIAN GEOTECHNICAL JOURNAL, vol. 41, no. 6, pp. 1098-1110.
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This study describes the effect of unsaturation at a drain boundary on the behaviour of a single prefabricated vertical drain subjected to vacuum preloading based on a two-dimensional plane strain finite element model incorporating the modified Cam-Clay model. Unsaturation of soil adjacent to the drain can occur due to mandrel withdrawal or application of vacuum pressure through prefabricated vertical band drains (PVDs). Following initial laboratory simulation in a large-scale radial drainage consolidometer, the authors have attempted to explain the observed retardation of pore pressure dissipation through a series of models, which consider the effect of unsaturation at the drain-soil interface. The results indicate that the introduction of an unsaturated soil layer adjacent to a PVD improves the accuracy of numerical predictions. Lastly, a multidrain analysis is conducted to study the behaviour of an embankment stabilized with vertical drains subjected to vacuum preloading, and the field measurements are compared with a series of numerical model predictions.
Khatri, RP, Sirivivatnanon, V & Heeley, P 2004, 'Critical polarization resistance in service life determination', CEMENT AND CONCRETE RESEARCH, vol. 34, no. 5, pp. 829-837.
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Lee, HK, Hewitson, S & Wang, J 2004, 'Web-based resources on GPS/INS integration', GPS Solutions, vol. 8, no. 3, pp. 189-191.
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The integrated GPS/INS system has become an indispensable tool for providing precise and continuous position, velocity and attitude information for many positioning and navigation applications, from surveying and mapping to vehicle navigation, guidance and control. There is an extensive variety of websites that are directly or indirectly related to the technologies and applications of GPS/INS integration. This column presents a selection of the publicly available web-based resources on research-based activities for GPS/INS integration. The selection encompasses those international universities and companies that provide electronic versions of their publications.
Li, J, Samali, B & Crews, K 2004, 'Determining individual member stiffness of bridge structures using a simple dynamic procedure', Acoustics Australia, vol. 32, no. 1, pp. 9-12.
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A reliable determination of the structural condition of timber bridges presently requires costly load testing. A new dynamic based testing method was developed by authors to reduce the cost and shorten the testing time. The method has been successfully used to undertake field-testing of more than 40 timber bridges across NSW. The dynamic testing procedure involves the attachment of accelerometers underneath the bridge girders. The bridge girders are then excited by a modal hammer. The method requires tests with and without extra mass, so that the overall flexural stiffness of the bridge can be obtained. However, in order to accurately estimate the load carrying capacity of the bridge, it is necessary to obtain the stiffness values of individual members from test results without complicating the current testing procedure. In this paper, the authors review the dynamic testing procedure and propose a method to determine individual member stiffness for a bridge structure based on the field dynamic testing data. The outcomes of this work not only enable more accurate prediction of the load carrying capacity of the bridge but will also identify defective members of the bridge structure.
Liu, B, Thomas, PS, Klimesch, DS & Ray, A 2004, 'Fourier transform infrared evaluation of autoclaved cellulose fibre pulps used in cement-based building materials', ADVANCES IN CEMENT RESEARCH, vol. 16, no. 4, pp. 131-136.
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Liu, B, Thomas, PS, Klimesch, DS & Ray, A 2004, 'Fourier transform infrared evaluation of autoclaved cellulose fibre pulps used in cement-based building materials', Advances in Cement Research, vol. 16, no. 4, pp. 131-136.
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Liu, B, Thomas, PS, Ray, AS & Williams, RP 2004, 'The effect of sampling conditions on the thermal decomposition of electrolytic manganese dioxide', JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, vol. 76, no. 1, pp. 115-122.
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The effect of sampling conditions on the decomposition of electrolytic manganese dioxide using thermal methods is reported. Significant differences were observed in the mechanism of the decomposition by simply changing the reaction environment from a closed pan to an open pan configuration. The purge gas atmosphere was also observed to influence the decomposition mechanism. As a product of the decomposition is oxygen, the change in the mechanism observed between the experimental conditions may be explained in terms of the ease of removal of oxygen from the reaction site.
Nejadi, S & Gilbert, I 2004, 'Shrinkage cracking and crack control in restrained reinforced concrete members', ACI STRUCTURAL JOURNAL, vol. 101, no. 6, pp. 840-845.
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Cracking caused by shrinkage in restrained reinforced concrete members is considered both experimentally and analytically. Eight longitudinally restrained slab specimens with different reinforcement layouts were monitored for up to 150 days to measure the effects of shrinkage on the time-dependent development of direct tension cracking. Strains in both the reinforcement and the concrete were monitored throughout the tests. The age of the concrete when each crack developed, the crack locations, and the gradual change in crack widths with time were also recorded. An analytical model developed previously to study the problem by Gilbert is modified and recalibrated and the experimental results and analytical predictions are compared. The effects of varying the quantity of reinforcing steel, the bar diameter, and the bar spacing are studied to gain a clearer understanding of the mechanism of direct tension cracking caused by restrained shrinkage and the factors affecting it.
Wang, J 2004, 'Pseudolite Augmentation for GPS Aided Aerial Photogrammetry: An Analysis of Systematic Errors.', Geomatics Research Australasia, vol. 81, pp. 30-44.
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GPS has been widely used as a geo-referencing tool in aerial surveying. However, the accuracy and availability of GPS positioning cannot meet the stringent requirements of large-scale photogrammetry. Ground-based pseudolites can strengthen measurement geometry for GPS based airborne geo-referencing systems. As a result, positioning accuracy and reliability can be improved, especially in the vertical component. However, as pseudolites are comparatively close to receivers, some challenging issues in systematic error analyses and modeling need to be further investigated. In this paper, the major systematic errors related to pseudolites, such as tropospheric delay, multipath and pseudolite location errors are analysed, and their impacts on the performance of an integrated GPS/Pseudolite airborne geo- reference system are presented.
Wu, C, Hao, H, Lu, Y & Sun, S 2004, 'Numerical simulation of structural responses on a sand layer to blast induced ground excitations', Computers & Structures, vol. 82, no. 9-10, pp. 799-814.
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Wu, C, Lu, Y & Hao, H 2004, 'Numerical prediction of blast‐induced stress wave from large‐scale underground explosion', International Journal for Numerical and Analytical Methods in Geomechanics, vol. 28, no. 1, pp. 93-109.
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AbstractThis paper presents a numerical model for predicting the dynamic response of rock mass subjected to large‐scale underground explosion. The model is calibrated against data obtained from large‐scale field tests. The Hugoniot equation of state for rock mass is adopted to calculate the pressure as a function of mass density. A piecewise linear Drucker–Prager strength criterion including the strain rate effect is employed to model the rock mass behaviour subjected to blast loading. A double scalar damage model accounting for both the compression and tension damage is introduced to simulate the damage zone around the charge chamber caused by blast loading. The model is incorporated into Autodyn3D through its user subroutines. The numerical model is then used to predict the dynamic response of rock mass, in terms of the peak particle velocity (PPV) and peak particle acceleration (PPA) attenuation laws, the damage zone, the particle velocity time histories and their frequency contents for large‐scale underground explosion tests. The computed results are found in good agreement with the field measured data; hence, the proposed model is proven to be adequate for simulating the dynamic response of rock mass subjected to large‐scale underground explosion. Extended numerical analyses indicate that, apart from the charge loading density, the stress wave intensity is also affected, but to a lesser extent, by the charge weight and the charge chamber geometry for large‐scale underground explosions. Copyright © 2004 John Wiley & Sons, Ltd.
Zhao, LC, Wu, CQ & Wang, Q 2004, 'Berry–Esseen Bound for a Sample Sum from a Finite Set of Independent Random Variables', Journal of Theoretical Probability, vol. 17, no. 3, pp. 557-572.
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Let {X 1,...,X N} be a set of N independent random variables, and let S n be a sum of n random variables chosen without replacement from the set {X 1,...,X N} with equal probabilities. In this paper we give an estimate of the remainder term for the normal approximation of S n under mild conditions.
Brennan, J, Martin, EA & Kim, M 1970, 'Developing an ontology of Spatial Relations', Visual and Spatial Reasoning in Design III, Visual and Spatial Reasoning in Design, Key Centre of Design Computing and Cognition, MIT,Cambridge, USA, pp. 163-182.
Chua, B & Brennan, J 1970, 'Enhancing Collaborative Knowledge Management Systems Designs', Proceedings 5th European Conference on Knowledge Management, European Conference on Knowledge Management, Academic Conferences International, Paris, France, pp. 171-179.
Crews, KI, Samali, B, Bakoss, SL & Champion, C 1970, 'Overview of Assessing Load Carrying Capacity of Timber Bridges Using Dynamic Methods', Proceedings of the Austroads 2004 Bridge Conference, Austroads Bridge Conference, Austroads Incorporated, Hobart, Australia, pp. 1-12.
Crews, KI, Samali, B, Bakoss, SL & Champion, C 1970, 'Testing and Assessment Procedures to Facilitate the Management of Timber Bridges Assets', The 3rd Civil Engineering Conference in the Asian Region Proceedings, The 3rd Civil Engineering Conference in the Asia Region, Asian Civil Engineering Coordination Council, Seoul, Korea, pp. 229-234.
Ding, GK 1970, 'The development of a multi-criteria approach for the measurement of sustainable performance of housing projects', Sustainability of the Housing Projects, XXXII IAHS World Congress, Sustainability of the Housing Projects, Univeristy of Trento, Trento, Italy, pp. 1-10.
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It has long been recognised that environmental matters are important to the survival of the construction industry. Yet, in general, the construction industry continues to degrade the environment, exploiting resources and generating waste, and is reluctant to change its conventional practices to incorporate environmental matters as part of the decisionmaking process. Building development involves complex decisions and the increased significance of external effects has further complicated the situation. Cost benefit analysis (CBA) is one of the conventional tools used widely by public and private sectors when appraising projects. It sets out to measure and compare the total costs and benefits of different projects that are competing for scarce resources in monetary terms. However, there are growing concerns that the values of environmental goods and services are often ignored or underestimated in the CBA approach which has led to the overuse and depletion of environmental assets. Consequently, CBA's usefulness and relevance in this respect is increasingly controversial. Project development is not just concerned with financial return, but is also conscious of the long-term impacts on living standards for both present and future generations. Sustainable development is an important issue in project decision-making and environmental effects need to be incorporated into the evaluation process.
Dowling, DM, Samali, B & Li, J 1970, 'Shake Table Testing of Unreinforced and Highly Reinforced U-shape Adobe-Mudbrick Wall Units', Australian Earthquake Engineering in the New Millenium, Australian Earthquake Engineering Society 2004 Conference, Australian Earthquake Engineering Society, Mt Gambier, Australia, pp. 1-6.
Friolo, KH, Ray, AS, Stuart, BH & Thomas, P 1970, 'Degradation of historic sandstone buildings of Sydney', Proceedings of the 7th Australasian Masonry Conference, University of Newcastle, Newcastle, pp. 420-427.
Friolo, KH, Ray, AS, Stuart, BH & Thomas, P 1970, 'Thermal analysis of yellow block sandstones in Sydney's heritage buildings', 13th International Congress on Thermal Analysis and Calorimetry Book of Abstracts, 13th International Congress on Thermal Analysis and Calorimetry, Sardinia.
Ha, QP, Nguyen, A & Trinh, HM 1970, 'Simultaneous State and Input Estimation with Application to a Two-Link Robotic System', Proceedings of the 5th Asian Control Conference, Asian Control Conference, IEEE, Melbourne, Australia, pp. 947-953.
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Scott, 1) Physical page no same as for other publication 'A Low-Order Linear......' ! 2) 2 X H Trinh at Deakin
Ha, QP, Nguyen, AD & Trinh, H 1970, 'Simultaneous state and input estimation with application to a two-link robotic system', 2004 5th Asian Control Conference, pp. 323-329.
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This paper addresses the problem of estimating simultaneously the state and input of a nonlinear system with application to a two link robotic manipulator - the Pendubot. The system nonlinearity comprises a Lipschitz function with respect to the state, and a nonlinear term which is a function of both the state and input. It is shown that under some conditions, an observer can be designed to estimate simultaneously the system's state and input. Simulation and experimental results, obtained around the inverted equilibrium position, are presented to demonstrate the validity of the approach.
Ha, QP, Tran, T & Trinh, HM 1970, 'Observer-Based Output Feedback Variable Structure Control with Application to a Two-Link Manipulator', Preprints of the 3rd IFAC Symposium on Mechatronics Systems, IFAC Symposium on Mechatronic Systems, Casual Productions, Glenelg North, SA, Australia, Sydney, Australia, pp. 133-138.
Ha, QP, Tran, TH & Trinh, H 1970, 'Observer-Based Output Feedback Variable Structure Control with Application to a Two-Link Manipulator', IFAC Proceedings Volumes, Elsevier BV, pp. 127-132.
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Copyright © IFAC Mechatronic Systems, Sydney, Australia, 2004. This paper proposes an approach to design dynamic output feedback sliding mode controllers for mismatched uncertain systems that are subject to perturbations in the output measurements. An asymptotic observer is first developed for the estimation of both the system state and unknown input. These estimates are then used to implement the equivalent control and the robust control for the system's desired sliding dynamics. Simulation and experimental results obtained for the Pendubot, a two-link manipulator, are presented to demonstrate the validity of the approach.
Ha, QP, Trinh, HM & Dissanayake, G 1970, 'A Low-Order Linear Functional Observer for Time Delay Systems', Proceedings of the 5th Asian Control Conference, Asian Control Conference, IEEE, Melbourne, Australia, pp. 947-955.
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Scott, 1)there are two Names H Trinh as stapled to front yellow page. & 2) the page numbers are the same as physically on the print off of Ha's other Public in this Conf 'Simultaneous State... ' !!
Ha, QP, Wu, Y, Samali, B & Li, J 1970, 'Earthquake Response of a Building Model with Base-Isolated Active Control', Preprints of the 3rd IFAC Symposium on Mechatronics Systems, IFAC Symposium on Mechatronic Systems, Casual Productions, Glenelg North, SA, Sydney, Australia, pp. 687-692.
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Place published ?- CD ROM
Ha, QP, Wu, YM, Samali, B & Li, J 1970, 'Earthquake Response of a Building Model with Base-Isolated Active Control', IFAC Proceedings Volumes, Elsevier BV, pp. 641-646.
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Copyright © IFAC Mechatronic Systems, Sydney, Australia, 2004. Base-isolated active control is employed in this paper for the protection of tall buildings against strong earthquakes with application to a five-storey benchmark building model. The control system consists of a base isolation system (laminated rubber bearings) connected to an active control system (a tuned mass damper and an actuator). Linear functional observers are used to reconstruct the control signal for systems with a limited number of sensors. The effectiveness of the proposed control system is tested with different ground motions: El-Centro 1940. Hachinohe 1968, Kobe 1995, and Northridge 1994 earthquakes. Numerical results show that the rubber bearing system alone can perform well against Hachinohe, Kobe, and Northridge ground motions, but not well enough to protect the model against El-Centro ground motion. With an active control system implemented to the rubber-isolated model, significant improvements in earthquake resistance against these four earthquakes arc obtained, especially against the El-Centro.
Indraratna, B, Khabbaz, H & Salim, W 1970, 'A laboratory study on improvement of railway ballast using geosynthetics', GEOTECHNICAL ENGINEERING FOR TRANSPORTATION PROJECTS, VOL 1, GeoTrans 2004 - Geotechnical Engineering for Transportation Projects, ASCE, Los Angeles, California, USA, pp. 617-626.
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The classical railway track basically consists of a flat framework made up of rails and sleepers, which are supported on ballasted track formation. Ballast particles breakdown and deteriorate progressively under heavy cyclic rail loading. Moreover, excessive consolidation settlement and progressive shear failure may occur in soft track formation under repetitive stresses. In order to rectify these problems, frequent maintenance operations are generally required in ballasted track. In order to minimize the deterioration of track substructure and also to reduce maintenance cost, the use of various types of geosynthetics including recycling of waste ballast have been studied in the laboratory. The prospective use of three types of geosynthetics (i.e. geogrids, geotextiles and geocomposites) in enhancing the performance of fresh and recycled ballast has been examined. The aspects of deformation and degradation of ballast under cyclic loading have been studied using a large-scale prismoidal triaxial rig. The research findings reveal that recycled ballast stabilized with geosynthetic reinforcement has a good potential for resilient track construction and for reducing the cost of track maintenance. The experimental findings may be beneficial to the railway engineers and encourage them to upgrade current tracks based on these innovative techniques.
Ip, K, Ray, AS, Stuart, BH & Thomas, P 1970, 'Degradation of historic sandstone buildings of Sydney', Proceedings of the 7th Australasian Masonry Conference, Australian Masonary Conference, University of Newcastle, Australia, pp. 420-427.
Nguyen, A, Ha, QP, Huang, S & Trinh, HM 1970, 'Observer-Based Decentralized Approach to Robotic Formation Control', Conference Proceedings, Australasian Conference on Robotics and Automation (ACRA 2004), Australasian Conference on Robotics and Automation, ARAA Australian Robotics & Automation Association, Canberra, Australia, pp. 1-8.
Nguyen, TVM, Nguyen, HT, Ha, QP & IEEE 1970, 'Sliding mode neural controller for nonlinear systems with higher-order and uncertainties', 2004 IEEE CONFERENCE ON ROBOTICS, AUTOMATION AND MECHATRONICS, VOLS 1 AND 2, IEEE Conference on Robotics, Automation and Mechatronics, IEEE, Singapore, pp. 1026-1031.
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In this paper, we propose a new neural controller architecture which is derived from adaptive sliding mode control framework for SISO nonlinear system with higher-order and uncertainties. This neural controller can overcome some disadvantages inherent in sliding mode controllers such as chattering problem, complex calculation of the equivalent control term and unavailable knowledge of the upper bounds of system uncertainties. Experimental results for a Coupled Drives CE8 system show that a real-time neural controller has been implemented successfully.
Sri Ravindrarajah, R, Farrokhzadi, F & to be deleted, A 1970, 'Properties of flowing concrete and self-compacting concrete with high-performance superplacticiser', Proceedings of the 3rd International RILEM Symposium, 3rd International Symposium on self-compacting concrete, RILEM Publications, Reykjavik, Iceland.
Sri Ravindrarajah, R, Siladyi, D & Adamopoulous, B 1970, 'The development of high strength self-compacting concrete with reduced segregation potential', Proceedings of the 3rd International RILEM Symposium, 3rd International Conference on Self-Compacting Concrete, RILEM Publications, Reykjavik, Iceland, pp. 1048-1050.
Tran, T, Ha, QP, Grover, R & Scheding, S 1970, 'Modelling of an Autonomous Amphibious Vehicle', Conference Proceedings, Australasian Conference on Robotics and Automation (ACRA 2004), Australasian Conference on Robotics and Automation, ARAA Australian Robotics & Automation Association, Canberra, Australia, pp. 1-7.
Tran, TH, Ha, QP & Dissanayake, G 1970, 'New wavelet-based,pitch detection method for human-robot voice interface', 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (IEEE Cat. No.04CH37566), 2004 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS) (IEEE Cat. No.04CH37566), IEEE, Sendai, Japan, pp. 527-532.
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Speech activated interface between human and autonomous/semi-autonomous systems requires accurate voice detection and recognition. In this area pitch and end-point detection is of vital importance. This paper presents a new method for pitch detection based on the phase of the continuous wavelet transform. The advantage of the proposed technique is that it can serve not only as an accurate pitch detector, but also can offer an efficient solution to the end-point detection problem. Experimental results are provided for the detection of pitch periods and end points in a neural-network based voice enabled wheelchair system.
White, R, Phillips, MR, Thomas, P, Wuhrer, R & Dredge, P 1970, 'Interactions Between Pigments in 19th and Early 20th Century Oil Paintings - In Situ Studies Using the Environmental Scanning Electron Microscope', Microscopy and Microanalysis, Microscopy and Microanalysis, Oxford University Press (OUP), Savannah, USA, pp. 132-133.
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Extended abstract of a paper presented at Microscopy and Microanalysis 2004 in Savannah, Georgia, USA, August 1–5, 2004.
Wu, CQ, Hao, H & Lu, Y 1970, 'Numerical simulation of damage of masonry and masonry infilled RC frame structures to blast ground motions', PROCEEDINGS OF THE EIGHTH INTERNATIONAL SYMPOSIUM ON STRUCTURAL ENGINEERING FOR YOUNG EXPERTS, VOLS 1 AND 2, 8th International Symposium on Structural Engineering for Young Experts, SCIENCE PRESS BEIJING, Xian, PEOPLES R CHINA, pp. 523-529.
