Abolhasan, M, Wysocki, T & Dutkiewicz, E 2004, 'A review of routing protocols for mobile ad hoc networks', Ad Hoc Networks, vol. 2, no. 1, pp. 1-22.
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The 1990s have seen a rapid growth of research interests in mobile ad hoc networking. The infrastructureless and the dynamic nature of these networks demands new set of networking strategies to be implemented in order to provide efficient end-to-end communication. This, along with the diverse application of these networks in many different scenarios such as battlefield and disaster recovery, have seen MANETs being researched by many different organisations and institutes. MANETs employ the traditional TCP/IP structure to provide end-to-end communication between nodes. However, due to their mobility and the limited resource in wireless networks, each layer in the TCP/IP model require redefinition or modifications to function efficiently in MANETs. One interesting research area in MANET is routing. Routing in the MANETs is a challenging task and has received a tremendous amount of attention from researches. This has led to development of many different routing protocols for MANETs, and each author of each proposed protocol argues that the strategy proposed provides an improvement over a number of different strategies considered in the literature for a given network scenario. Therefore, it is quite difficult to determine which protocols may perform best under a number of different network scenarios, such as increasing node density and traffic. In this paper, we provide an overview of a wide range of routing protocols proposed in the literature. We also provide a performance comparison of all routing protocols and suggest which protocols may perform best in large networks.
Glamore, W & Indraratna, B 2004, 'A two-stage decision support tool for restoring tidal flows to flood mitigation drains affected by acid sulfate soil: Case study of Broughton Creek floodplain, New South Wales, Australia', Australian Journal of Soil Research, vol. 42, no. 5-6, pp. 639-648.
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A 2-stage flood estimation and water quality decision support tool (DST) was developed, calibrated, and applied to a field site in south-eastern New South Wales (NSW) to simulate tidal restoration in a flood mitigation drain affected by acid sulfate soils leachate. The first stage of the DST employs a digital terrain map, geographic information tools, and measured water levels to calculate drain water overtopping due to tidal variations. Simulations using the GIS technique at the study site indicated that the primary drainage network can safely contain full tidal flushing (0.91 m AHD or a 58% increase), whereas at the same level the secondary drainage network overtops along relict drainage channels. The second stage of the DST simulates the change in drain water quality using an ion-specific program code written within the open interface PHREEQC program. The results from the water quality model were calibrated against laboratory titration tests. Drain water pH was shown to increase above 6.0, and soluble aluminium and iron concentrations decreased by 73% and 56%, respectively. The extent of water quality change is directly related to the ionic strength of the intruding water and the ion-specific reaction kinetics of aluminium, iron, and sulfate. Based on the DST simulations, floodgate modifications to restore tidal flushing were successfully undertaken at a study site near Berry, in south-eastern NSW. DST predictions accurately simulated field results (±10%) and slight variations between data were attributed to the prolonged drought at the field site, which increased the ionic strength of intruding waters, and the high concentration of sulfate in seawater. The DST can be easily adapted to other sites throughout Australia.
Huang, W, Sheng, D, Sloan, SW & Yu, HS 2004, 'Finite element analysis of cone penetration in cohesionless soil', Computers and Geotechnics, vol. 31, no. 7, pp. 517-528.
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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.
Jeng, D-S, Cha, DF & Blumenstein, M 2004, 'Neural network model for the prediction of wave-induced liquefaction potential', Ocean Engineering, vol. 31, no. 17-18, pp. 2073-2086.
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The prediction of wave-induced liquefaction has been recognised by coastal geotechnical engineers as an important factor when considering the design of marine structures. All existing models have been based on conventional approaches of engineering mechanics with limited laboratory work. In this study, we propose an alternative approach for the prediction of the maximum liquefaction depth, based on neural network (NN). Unlike previous engineering mechanics approaches, the proposed NN model is based on data learning knowledge, rather than on knowledge of mechanisms. Numerical examples demonstrate the capacity of the proposed NN model for the prediction of wave-induced liquefaction depth, which provides civil engineers with another effective tool. © 2004 Elsevier Ltd. All rights reserved.
Ji, JC 2004, 'Dynamics of a piecewise linear system subjected to a saturation constraint', JOURNAL OF SOUND AND VIBRATION, vol. 271, no. 3-5, pp. 905-920.
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The dynamics of a periodically forced single-degree-of-freedom linear system with a proportional feedback control subjected to a saturation constraint is investigated in detail. Emphasis is placed on the determination of a double-entering saturation region per cycle periodic motion. Symmetric period-one solutions are derived analytically and their stability characteristics are determined. Other kinds of solutions such as asymmetric, subharmonic and chaotic solutions as well as multiple-crossing saturation region per cycle periodic solutions, found through numerical simulations, are also presented.
Ji, JC & Hansen, CH 2004, 'Analytical approximation of the primary resonance response of a periodically excited piecewise non-linear-linear oscillator', JOURNAL OF SOUND AND VIBRATION, vol. 278, no. 1-2, pp. 327-342.
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An analytical approximate solution is constructed for the primary resonance response of a periodically excited non-linear oscillator, which is characterized by a combination of a weakly non-linear and a linear differential equation. Without eliminating the secular terms, a valid asymptotic expansion solution for the weakly non-linear equation is analytically determined for the case of primary resonances. Then, a symmetric periodic solution for the overall system is obtained by imposing continuity and matching conditions. The stability characteristic of the symmetric periodic solution is investigated by examining the asymptotic behaviour of perturbations to the steady state solution. The validity of the developed analysis is highlighted by comparing the first order approximate solutions with the results of numerical integration of the original equations.
Ji, JC & Hansen, CH 2004, 'Approximate solutions and chaotic motions of a piecewise nonlinear-linear oscillator', CHAOS SOLITONS & FRACTALS, vol. 20, no. 5, pp. 1121-1133.
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A global symmetric period-1 approximate solution is analytically constructed for the non-resonant periodic response of a periodically excited piecewise nonlinear-linear oscillator. The approximate solutions are found to be in good agreement with the exact solutions that are obtained from the numerical integration of the original equations. In addition, the dynamic behaviour of the oscillator is numerically investigated with the help of bifurcation diagrams, Lyapunov exponents, Poincare maps, phase portraits and basins of attraction. The existence of subharmonic and chaotic motions and the coexistence of four attractors are observed for some combinations of the system parameters. © 2003 Elsevier Ltd. All rights reserved.
Ji, JC & Leung, AYT 2004, 'Periodic and chaotic motions of a harmonically forced piecewise linear system', INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES, vol. 46, no. 12, pp. 1807-1825.
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Ji, JC & Leung, AYT 2004, 'Periodic and chaotic motions of a harmonically forced piecewise linear system', International Journal of Mechanical Sciences, vol. 46, no. 12, pp. 1807-1825.
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The dynamics of a harmonically excited single degree-of-freedom linear system with a feedback control, in which the actuator is subjected to dead zone and saturation constraints, is investigated in detail. The controlled system is mathematically modeled by a set of three piecewise linear equations. It is found that the system may exhibit nine types of symmetric and asymmetric period-one motions, which are characterized by a different number of crossing dead zone and saturation region per cycle. A solution for the symmetric period-one motion with a doubly crossing dead zone and saturation region is analytically constructed and its stability characteristics is examined. Other types of dynamic response such as sub-harmonic periodic motions and chaotic motions, found through numerical simulations, are also presented.
Leung, AYT, Ji, JC & Chen, GR 2004, 'Resonance control for a forced single-degree-of-freedom nonlinear system', INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS, vol. 14, no. 4, pp. 1423-1429.
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The main characteristic of a forced single-degree-of-freedom weakly nonlinear system is determined by its primary, super- and sub-harmonic resonances. A nonlinear parametric feedback control is proposed to modify the steady-state resonance responses, thus to reduce the amplitude of the response and to eliminate the saddle-node bifurcations that take place in the resonance responses. The nonlinear gain of the feedback control is determined by analyzing the bifurcation diagrams associated with the corresponding frequency-response equation, from the singularity theory approach. It is shown by illustrative examples that the proposed nonlinear feedback is effective for controlling three kinds of resonance responses.
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.
Salim, W & Indraratna, B 2004, 'A new elastoplastic constitutive model for coarse granular aggregates incorporating particle breakage', Canadian Geotechnical Journal, vol. 41, no. 4, pp. 657-671.
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A new elastoplastic stressstrain constitutive model is developed for granular coarse aggregates incorporating the degradation of particles during triaxial shearing. Coarse granular aggregates are subjected to breakage during excessive stress changes. Most of the available constitutive models do not consider the degradation of particles during shearing. In the current model, a plastic flow rule has been developed incorporating the energy consumption due to particle breakage during shear deformation. A non-associated flow and a kinematic type yield locus have been adopted in the model. A general formulation for the rate of particle breakage during shearing has been developed and incorporated in the plastic flow rule. The effects of particle breakage on the plastic distortional and volumetric deformations are incorporated in the current model. The stressstrain formulations are developed within the general critical state framework. The model can accurately predict the stressstrain and volume change behaviour of coarse granular aggregates. The plastic dilation and contraction features of coarse aggregates at various confining pressures are well captured, and the strain-hardening and post-peak strain-softening behaviour of coarse granular media is adequately represented. A particular feature of the model is its capability to predict the degree of particle breakage at any stage of shear deformation.Key words: constitutive modelling, coarse granular aggregates, particle breakage, dilatancy, non-associated flow, plasticity.
Sheng, D, Sloan, SW & Gens, A 2004, 'A constitutive model for unsaturated soils: thermomechanical and computational aspects', Computational Mechanics, vol. 33, no. 6, pp. 453-465.
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Verma, B, Blumenstein, M & Ghosh, M 2004, 'A novel approach for structural feature extraction: Contour vs. direction', Pattern Recognition Letters, vol. 25, no. 9, pp. 975-988.
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The paper presents a novel approach for extracting structural features from segmented cursive handwriting. The proposed approach is based on the contour code and stroke direction. The contour code feature utilises the rate of change of slope along the contour profile in addition to other properties such as the ascender and descender count, start point and end point. The direction feature identifies individual line segments or strokes from the character's outer boundary or thinned representation and highlights each character's pertinent direction information. Each feature is investigated employing a benchmark database and the experimental results using the proposed contour code based structural feature are very promising. A comparative evaluation with the directional feature and existing transition feature is included. © 2004 Elsevier B.V. All rights reserved.
Abolhasan, M, Lipman, J, Chicharo, J & ieee 1970, 'A routing strategy for heterogeneous Mobile Ad Hoc Networks', PROCEEDINGS OF THE IEEE 6TH CIRCUITS AND SYSTEMS SYMPOSIUM ON EMERGING TECHNOLOGIES: FRONTIERS OF MOBILE AND WIRELESS COMMUNICATION, VOLS 1 AND 2, Emerging Technologies: Frontiers of Mobile and Wireless Communication, 2004., In the 5th IEEE International Conference on Wireless Communications, Networking and Mobile Computing, Shanghai, Shanghai, China, pp. 13-16.
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This paper presents a new routing strategy for heterogeneous Mobile Ad Hoc Networks. We refer to this strategy as On-demand Utility-Based Routing Protocol (OUBRP). This protocol introduces a Utility-Based route discovery strategy, which aims to minimise the number of control packets disseminated into the network during route discovery by efficiently using available resources at each node. Furthermore, we propose a new strategy to eliminate uni-directional links during the route discovery phase. We refer to this strategy as Uni-directional Link Elimination (ULE). We performed a simulation study to compare the performance of OUBRP with a number of different routing protocols proposed for MANETs. Our results show that OUBRP compared to other routing strategies produces significantly fewer control packets and achieves higher levels of successful packet delivery with increasing number of nodes. Furthermore, we propose a number of alternative Uni-directional Link Elimination strategies.
Blumenstein, M 1970, 'Experience in teaching object-oriented concepts to first year students with diverse backgrounds', International Conference on Information Technology: Coding and Computing, 2004. Proceedings. ITCC 2004., International Conference on Information Technology: Coding and Computing, 2004. Proceedings. ITCC 2004., IEEE, pp. 704-708.
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This paper describes the experiences in coordinating a first year programming course at Griffith University since Semester 1, 2000. In this time, the course structure and content have evolved to implement and evaluate an "objects-as-needed" approach to first year programming with the recent return to an "objects-early" approach. A variety of assessment strategies have also been employed in order to maximize student-learning outcomes. The success of the revised course has continuously been measured by evaluating student feedback and performance. Finally, a focus group-based strategy of evaluation was adopted to determine students' attitudes to the most recently implemented changes.
Blumenstein, M, Green, S, Nguyen, A & Muthukkumarasamy, V 1970, 'An experimental analysis of GAME', ACM SIGCSE Bulletin, Association for Computing Machinery (ACM), pp. 67-71.
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This paper describes the Generic Automated Marking Environment (GAME) and provides a detailed analysis of its performance in assessing student programming projects and exercises. GAME has been designed to automatically assess programming assignments written in a variety of languages based on the 'structure' of the source code and the correctness of the program's output. Currently, the system is able to mark programs written in Java, C++ and the C language. To use the system, instructors are required to provide a simple 'marking schema' for any given assessment item, which includes pertinent information such as the location of files and the model solution. In this research, GAME has been tested on a number of student programming exercises and assignments. The results obtained, have been analysed and compared against a human marker providing encouraging results.
Blumenstein, M, Green, S, Nguyen, A & Muthukkumarasamy, V 1970, 'An experimental analysis of GAME', Proceedings of the 9th annual SIGCSE conference on Innovation and technology in computer science education, ITiCSE04: Innovation and Technology in Computer Science Education, ACM, pp. 67-71.
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This paper describes the Generic Automated Marking Environment (GAME) and provides a detailed analysis of its performance in assessing student programming projects and exercises. GAME has been designed to automatically assess programming assignments written in a variety of languages based on the "structure" of the source code and the correctness of the program's output. Currently, the system is able to mark programs written in Java, C++ and the C language. To use the system, instructors are required to provide a simple "marking schema" for any given assessment item, which includes pertinent information such as the location of files and the model solution. In this research, GAME has been tested on a number of student programming exercises and assignments. The results obtained, have been analysed and compared against a human marker providing encouraging results.
Blumenstein, M, Green, S, Nguyen, A & Muthukkumarasamy, V 1970, 'GAME: A Generic Automated Marking environment for programming assessment', ITCC 2004: INTERNATIONAL CONFERENCE ON INFORMATION TECHNOLOGY: CODING AND COMPUTING, VOL 1, PROCEEDINGS, pp. 212-216.
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In this paper, a Generic Automated Marking Environment (GAME) is proposed for assessing student programming projects and exercises with an aim to facilitate student-centred learning. GAME has been designed to automatically assess programming assignments written in a variety of languages. The system has been implemented in Java and contains marker modules that are tailored to each specific language. A framework has been set in place to enable easy addition of new marker modules to extend the system's functionality. Currently, the system is able to mark programs written in Java and the C language. To use the system, instructors are required to provide a simple "marking schema" for any given assessment item, which includes pertinent information such as the location affiles and the model solution. GAME has been tested on a number of student programming exercises and assignments providing encouraging results.
Blumenstein, M, Liu, XY & Verma, B 1970, 'A modified direction feature for cursive character recognition', 2004 IEEE International Joint Conference on Neural Networks (IEEE Cat. No.04CH37541), 2004 IEEE International Joint Conference on Neural Networks, IEEE, pp. 2983-2987.
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This paper describes a neural network-based technique for cursive character recognition applicable to segmentation-based word recognition systems. The proposed research builds on a novel feature extraction technique that extracts direction information from the structure of character contours. This principal is extended so that the direction information is integrated with a technique for detecting transitions between background and foreground pixels in the character image. The proposed technique is compared with the standard direction feature extraction technique, providing promising results using segmented characters from the CEDAR benchmark database.
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.
Glamore, W & Indraratna, B 1970, 'A two-stage decision support tool for restoring tidal flows to flood mitigation drains affected by acid sulfate soil: case study of Broughton Creek floodplain, New South Wales, Australia', Soil Research, 5th International Acid Sulfate Soil Conference, CSIRO Publishing, Tweed Heads, AUSTRALIA, pp. 639-639.
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A 2-stage flood estimation and water quality decision support tool (DST) was developed, calibrated, and applied to a field site in south-eastern New South Wales (NSW) to simulate tidal restoration in a flood mitigation drain affected by acid sulfate soils leachate. The first stage of the DST employs a digital terrain map, geographic information tools, and measured water levels to calculate drain water overtopping due to tidal variations. Simulations using the GIS technique at the study site indicated that the primary drainage network can safely contain full tidal flushing (0.91 m AHD or a 58% increase), whereas at the same level the secondary drainage network overtops along relict drainage channels. The second stage of the DST simulates the change in drain water quality using an ion-specific program code written within the open interface PHREEQC program. The results from the water quality model were calibrated against laboratory titration tests. Drain water pH was shown to increase above 6.0, and soluble aluminium and iron concentrations decreased by 73% and 56%, respectively. The extent of water quality change is directly related to the ionic strength of the intruding water and the ion-specific reaction kinetics of aluminium, iron, and sulfate.
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
Halkon, B & Rothberg, S 1970, 'Automatic post-processing of laser vibrometry data for rotor vibration measurements', IMechE Event Publications, 8th International Conference on Vibrations in Rotating Machinery, PROFESSIONAL ENGINEERING PUBLISHING LTD, Univ Wales Swansea, Swansea, WALES, pp. 215-230.
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The Laser Vibrometer constitutes a potentially powerful vibration transducer for measurements directly from rotating components. Radial, axial, pitch/yaw and torsional vibrations can all be measured using either single beam or parallel beam Laser Vibrometers. Successful application, however, requires a clear appreciation of the effects of laser speckle and of how radial and pitch/yaw vibration measurements from rotors contain significant cross-sensitivities to motion perpendicular to the intended measurement. Making use of two orthogonal vibration measurements and an independent speed measurement it is possible to eliminate cross-sensitivity from measured data at all non-synchronous frequencies but a convenient, practical means to undertake the necessary data processing has not been available until now. A Lab VIEW based real-time version of this essential resolution technique will be presented for the first time in this paper. This paper describes a number of example measurements. Radial and pitch/yaw vibration measurements will demonstrate the use of the resolution technique to show effects such as the excitation of the first bending mode of the crankshaft. A torsional vibration measurement on a crankshaft pulley will show the influence of speckle noise and alignment issues will be discussed to limit the pitch/yaw vibration sensitivity. Differential torsional measurements on rotating components can be used to examine, for example, the twisting across a flexible coupling and the stretching of a drive belt; speckle effects are again important. © IMechE 2004.
Halkon, BJ & Rothberg, SJ 1970, 'Synchronized-scanning laser vibrometry', SPIE Proceedings, Sixth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications, SPIE, Ancona, ITALY, pp. 260-271.
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The use of Laser Vibrometers incorporating some form of manipulation of the laser beam orientation, typically using two orthogonally aligned mirrors, has become increasingly popular in recent years with considerable attention being given to the operation of such scanning Laser Vibrometers in continuous scanning mode. Here the laser beam orientation is a continuous function of time, making it possible, for example, to track a single point on a moving target such as a rotating bladed disc. A recently derived comprehensive velocity sensitivity model has been developed to incorporate time-dependent beam orientation enabling confident and detailed analysis of data obtained in such measurements. The model predicts the measured velocity for arbitrary mirror scan angles and arbitrary target motion and is shown to be especially valuable in revealing the sources of additional components that occur in continuous scanning and tracking measurements on rotors. The development of the comprehensive velocity sensitivity model and of sophisticated measurement hardware and software has resulted in proposal of the exciting new Synchronised-Scanning Laser Vibrometry technique. Introduced for the first time in this paper, the measurement involves the probe laser beam tracking the rotating structure and simultaneously scanning the region of interest to provide modal data under operating conditions, i.e. during rotation. Such a measurement is inconceivable by any other means and the system that has been created has the potential to provide data of fundamental importance in the design and development of a wide range of devices from hard disk drives to gas turbines.
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.
Indraratna, B, Raut, A & Locke, M 1970, 'Granular Filters in Embankment Dams: A Conceptual Overview and Experimental Investigation', Geo Jordan 2004, Geo Jordan Conference 2004, American Society of Civil Engineers, pp. 15-34.
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In contrast to empirical design, rigorous analytical modeling and numerical simulations provide useful predictions on time-dependent changes in filters, and the potential rate of base soil erosion from the dame core under various geo-hydraulic constraints. Moreover, simulation of filtration phenomenon by numerical schemes provides a good idea of the minimum filter thickness, based on its retention capacity. In this Keynote paper, governing equations are developed considering the principles of mass and momentum conservation combined with appropriate seepage criteria and the equations are solved by finite difference procedure to simulate the time-dependent changes in filters. The important contribution of various void models and seepage conditions assumed by various researchers are discussed and compared, identifying their scope and limitations within the framework of practical dam engineering. The theoretical developments are verified through large-scale laboratory testing for both cohesive and non-cohesive base soils.
Liu, XY & Blumenstein, M 1970, 'Experimental Analysis of the Modified Direction Feature for Cursive Character Recognition', Ninth International Workshop on Frontiers in Handwriting Recognition, Ninth International Workshop on Frontiers in Handwriting Recognition, IEEE, pp. 353-358.
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This paper describes and analyzes the performance of a structural feature extraction technique for the recognition of segmented/cursive characters that may be used in the context of a segmentation-based, handwritten word recognition system. The Modified Direction Feature (MDF) extraction technique builds upon a previous technique proposed by the authors that extracts direction information from the structure of character contours. This principle is extended so that the direction information is integrated with a technique for detecting transitions between background and foreground pixels in the character image. The MDF technique used in conjunction with neural network classifiers provide recognition rates of up to 90.24%, which are amongst the highest in the literature. This paper also presents a detailed analysis of the characters that were the source of misclassification in the character recognition process. The characters used for experimentation were obtained from the CEDAR benchmark database. © 2004 IEEE.
Nazem, M & Sheng, D 1970, 'Alternative solution methods for large deformations in geomechanics', Numerical Models in Geomechanics - 9th Proceedings of the International Symposium on Numerical Models in Geomechanics, NUMOG 2004, pp. 265-272.
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Three different methods for handling large-deformation problems are discussed and compared in this study. These methods include theTotal-Lagrangian (TL), the Updated-Lagrangian (UL) and the Arbitrary- Lagrangian-Eulerian (ALE) methods. Due to different formulations of the local stress–strain relation, the UL method is further complicated with three different implementations. The ALE method presented in this paper is based on operator-split technique where the analysis is carried out in two steps; an UL step followed by an Eulerian step. In the first step, one of the UL procedures is performed to achieve the equilibrium. In the second step, the mesh is redefined and all kinematic and static variables are transferred to the new mesh using the convective velocity. This paper also introduces a new method for mesh refinement in the ALE method. Using the known displacements at domain boundaries and material interfaces as prescribed displacements, the problem is re-analysed by assuming linear elasticity and the deformed mesh resulting from such a analysis is then used the new mesh in the second step of the ALE method. It is shown that this repeated elastic analysis is actually more efficient than mesh generation and it can be used for general cases regardless of problem dimension and problem topology. Their relative performance of the TL, UL and ALE methods is investigated through the analyses of some classic geotechnical problems.
Rothberg, SJ & Halkon, BJ 1970, 'Laser vibrometry meets laser speckle', SPIE Proceedings, Sixth International Conference on Vibration Measurements by Laser Techniques: Advances and Applications, SPIE, Ancona, ITALY, pp. 280-291.
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This paper begins with a review of the fundamental mechanism by which speckle noise is generated in Laser Vibrometry before describing a new numerical simulation of speckle behaviour for prediction of noise level in a real measurement. The simulation data provides real insight into the phase and amplitude modulation of the Doppler signal as a result of speckle changes. The paper also includes experimental data looking at the influence of speckle noise in measurements on rotors with a selection of surface treatments and in scanning and tracking configurations.
