ENGINEERING FACULTY
| Researcher : Chew WC |
| Project Title: | Computational Electromagnetics for Broadband Integrated Circuit and Package Applications |
| Investigator(s): | Chew WC |
| Department: | Engineering Faculty |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2009 |
| Abstract: |
| 1. We aim to improve and develop new analysis methods and tools to meet the cutting edge demand of the computer electronic industry. We will develop the next generation fast, efficient, and highly stable algorithm for such problems. We will achieve this with fast integral equation solvers for electromagnetic field by incorporating novel techniques and hierarchical approach using the equivalence principle algorithm (EPA). An accurate form of the EPA will be developed that is error-controllable.; 2. We will develop methods so that multi-scale computational electromagnetics solvers are stabilized. We will rectify the low-frequency break down of the fast algorithms in this regime as well as develop new acceleration techniques. The low-frequency breakdown of the fast algorithm will be overcome with mixed-form fast multipole algorithm or vector mixed-form fast multipole algorithm. The low frequency breakdown of the integral equation solvers will be rectified with loop-tree decomposition, mixed basis, and EPA.; 3. Iterative solvers do not work well, and we aim to develop preconditioners to improve their convergence. These preconditioners will be physics-based. Hence, we will develop successfully these preconditioners by using physical and mathematical understanding.; 4. We will apply the newly developed algorithms to real-world problems, and compare with experimental data collected by other groups around the world.; 5. We will disseminate the work with conference presentations, journal publications, and seminars, whenever opportunity arises. |
| Project Title: | Design of Broadband RFID Tag Antenna for Complex Environments |
| Investigator(s): | Chew WC, Chen Y, Huang J, Yang P |
| Department: | Engineering Faculty |
| Source(s) of Funding: | Innovation and Technology Support Programme (Tier 3) |
| Start Date: | 10/2009 |
| Abstract: |
| In many RFID systems, dipoles are often used as tag antennas. Dipole-type antennas have the merits of low-cost, easy to design but have the drawbacks of ambiance sensitivity and especially cannot be attached on metallic platform. Microstrip antenna is considered to be a more robust antenna which is immune to the back material. However, it is generally agreed that compact, low profile microstrip antenna has narrow band and low gain, which severely constrain its applications in RFID systems. One goal of the project is to design compact, broadband and globally versatile tag antennas that can be attached to various kinds of packages. Most commercial software is not capable of modeling the performance of antennas in complex environment, because the number of unknowns is so humongous that it exhausts the resource of CPU and memory rapidly. Another goal of the project is to propose novel algorithms to accelerate the overall computation and develop a simple efficient antenna design simulation tool which can simulate the antenna not only in free space but also in complex environment, such as packages in stacks or stored in a warehouse. |
| Project Title: | Fast Algorithm for Solving Augmented Electric Field Integral Equation for Multiscale Structures over a Broad Bandwidth |
| Investigator(s): | Chew WC |
| Department: | Engineering Faculty |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2010 |
| Abstract: |
| 1) We will use the vector addition theorem to develop a new vector mixed-form fast multipole algorithm (vector MF-FMA) for broadband acceleration of integral equations. This algorithm is estimated to reduce memory and CPU usage by a factor of two; 2) We will use the vector MF-FMA to accelerate a new form of the augmented electric field integral equation (AEFIE) to reduce memory and CPU usage so that larger than one million unknown problems can be routinely solved on a personal computer; 3) We will extend the development of the augmented electric field integral equation (AEFIE) to dielectric layered media. We will develop a highly stable integral equation for such problems. This will greatly enhance the usefulness of AEFIE for many real world applications where layered structures are commonly encountered, such as in computer chip design; 4) We will accelerate the layered-medium integral equation with fast algorithm, namely, the thin-stratified fast multipole algorithm (TS-FMA) for electromagnetic field, but extending it over a broad bandwidth. We will apply the equivalence of MF-FMA for layered media to achieve the broad bandwidth capability; 5) As is the case for new integral equations, we will develop preconditioners to improve the convergence of AEFIE. We will develop these preconditioners by using physical insight and mathematical understanding. These preconditioners will greatly reduce the iteration numbers needed to solve the integral equations iteratively; 6) We will apply the newly developed algorithms to real-world problems, and test the algorithms with real-world structures suggested by the industries, and compare with experiments whenever possible; 7) We will disseminate the work with conference presentations, journal publications, and seminars, whenever opportunity arises. |
| Project Title: | Design of Ambience Immune RFID Tag Antennas Inspired by Metamaterials |
| Investigator(s): | Chew WC, Jiang L, Yang P, Huang J |
| Department: | Engineering Faculty |
| Source(s) of Funding: | Innovation and Technology Support Programme (Tier 3) |
| Start Date: | 03/2010 |
| Abstract: |
| In many RFID systems, dipoles are often used as tag antennas. Dipole-type antennas have the merits of low-cost, easy to design but have the drawbacks of ambiance sensitivity and cannot be attached on metallic platform. Microstrip antenna is considered to be a more robust antenna which is immune to the back material. However, it is generally large in size which prohibits its application in small objects, and the gain is low making long-range reading unrealizable. The objectives of this proposed project are to design some novel RFID tags Inspired by new mechanism which will considerable increase the read range. For small objects such as cans and bottles, compact tags which may be as small as a coin will be designed with acceptable read range. Most commercial software is not suitable for modeling antennas based on metamaterials because of elaborate structures. Another goal of the project is to use fast algorithms to accelerate the overall computation and develop a simple efficient simulation tool. |
| List of Research Outputs |
| Atkins P.R. and Chew W.C., Fast Computation of the Dyadic Green's Function for Layered Media Via Interpolation, In: G Lazzi, IEEE Antennas and Wireless Propagation Letters. 2010, 9: 493-496. |
| Atkins P.R. and Chew W.C., Tabulation and Interpolation of the Dyadic Green's Function for Layered Media, University of Illinois at Urbana-Champaign. University of Illinois at Urbana-Champai, 2009, CCEML 3-09. |
| Qian Z., Li M., Ma Z., Jiang L. and Chew W.C., Solving Multiscale Low Frequency Electromagnetic Problems, The 4th European Conference on Antennas and Propagation. 2010. |
| Sha W., Choy W.C.H. and Chew W.C., A Comprehensive Study for the Plasmonic Thin-Film Solar Cell with Periodic Structure, Optics Express. 2010, 18: 5993(15pp). |
| Sha W. and Chew W.C., High Frequency Scattering by An Impenetrable Sphere, Progress In Electromagnetics Research. 2009, 97: 291-325. |
| Xiong J.L., Tong M.S., Atkins P.R. and Chew W.C., Efficient Evaluation Of Casimir Force In Arbitrary Three-dimensional Geometries By Integral Equation Methods , In: V.M. Agranovich A.R. Bishop C.R. Doering A.P. Fordy P.R. Holland F. Porcelli R.Q. Wu , Physics Letters A. 2010, 374: 2512-2520. |
| Researcher : Chin FYL |
| Project Title: | MultiVision Fund |
| Investigator(s): | Chin FYL |
| Department: | Computer Science |
| Source(s) of Funding: | MultiVision Intelligent Surveillance (Hong Kong) Ltd. - General Award |
| Start Date: | 07/2003 |
| Abstract: |
| MultiVision Fund. |
| Project Title: | A new motif representation based on position specific patterns |
| Investigator(s): | Chin FYL |
| Department: | Computer Science |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 09/2006 |
| Completion Date: | 02/2010 |
| Abstract: |
| 1 We want to introduce a good model to represent motifs and describe them in a precise and complete fashion. 2 Based on our new motif representation model, we will redefine the motif discovering problem and design efficient algorithms or heuristics to solve the problem. 3 The goal of the new model is to enable the discovery of a higher percentage of known motifs and some unknown motifs. |
| Project Title: | Design and Analysis of Online Algorithms for Frequency/Code Assignment Problems in Cellular Networks |
| Investigator(s): | Chin FYL |
| Department: | Computer Science |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 09/2007 |
| Completion Date: | 02/2010 |
| Abstract: |
| (1) The first objective of this project is to develop novel techniques to solve the fundamental online frequency/code assignment problem, where all calls are assumed to request the same fixed data rate, and so frequencies/codes are labeled by integers. We consider the problem for a network with hexagonal cells or with a more general topology and with different reuse distances.(2) The second objective is to consider third-generation (3G) networks that use W-CDMA/OVSF technology which allows variable data rates to be requested by calls. This is a much harder problem which involves assignment, and possibly reassignment, of orthogonal codes to calls, using a code tree structure. |
| Project Title: | Finding Conserved Patterns in Biological Networks |
| Investigator(s): | Chin FYL |
| Department: | Computer Science |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 10/2008 |
| Abstract: |
| 1. Finding some restricted common patterns. Even though the problem of finding common patterns is usually NP-complete, we can study restricted common patterns giving rise to problems which can be solved in polynomial time, but without sacrificing the practicality of the solution. Usually the common patterns are of small size, so it is likely that we can design algorithms which can practically solve the problem without taking exponential time with respect to the size of the networks. Furthermore, some common patterns can be modeled by trees or cycles of repeated vertices. We expect that finding common patterns, when restricted to these topologies and when given the one-one correspondence of the vertices in the networks, can be solved in polynomial time. This achieved, our goal thereafter would be to study the finding of restricted common patterns when the vertex mapping might not be a one-one correspondence (but with each vertex mapped to a small constant number of vertices) and for multiple networks.; 2. Finding common patterns with missing edges. Because of the noisy data and incomplete experiments, some edges in the network might be missing (different from mismatches). The identification of a common path with one missing edge reduces to the problem of finding disjoint paths whose union matches well with the common path except by one edge. This problem can be extended to more missing edges, other subgraph topologies (other than paths) and for multiple networks.; 3. Verification by experiments on real data. The effectiveness and efficiency of our proposed algorithms will be implemented and tested on a number of databases available on biological networks. The accuracy of our algorithms will be determined by comparing our results with the known solutions. |
| Project Title: | Flexible Framework for GPGPU-based Video Decoding and Post-processing. |
| Investigator(s): | Chin FYL, Chow KP |
| Department: | Computer Science |
| Source(s) of Funding: | Innovation and Technology Support Programme (Tier 3) |
| Start Date: | 09/2009 |
| Abstract: |
| The objective of this project is to develop a flexible framework and toolset for utilizing the General Purpose Graphics Processing Unit (GPGPU) in high-definition video decoding and pos t-processing. Although there are software packages which make use of the GPGPU for high-definition video decoding and post-processing, these software packages, however, are usually proprietary and not flexible enough to allow further applications to be built upon them. Besides, from technical perspective most of the existing solutions focused on employing GPGPU to perform one single video stream decoding, without noting that there might be cases where multiple video streams, for instance in video surveillance, have to be decoded simultaneously. In this project, we will have a deeper exploration on how to utilize GPGPU in a more flexible way, and to define a framework and to develop a toolset so that multiple high-definition video streams decoding and post-processing can be properly offloaded to the GPGPU. With this toolset, potential applications including high-definition video editing, transcoding, etc. can be realized, but it can be ascertained that video surveillance industry in Hong Kong can be directly benefited by the toolset developed in this project as it addresses the fundamental problems in decoding multiple high-definition video streams on a typical workstation. |
| Project Title: | Combinatorial Phenotype Testing |
| Investigator(s): | Chin FYL |
| Department: | Computer Science |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2010 |
| Abstract: |
| 1) Finding sequential and non-adaptive algorithms for the phenotype testing problem with mixed AND/OR-phenotypes using fewer tests. |
| Project Title: | The 14th International Conference on Research in Computational Molecular Biology (RECOMB 2010) IDBA - A Practical Iterative de Bruijn Graph De Novo Assembler |
| Investigator(s): | Chin FYL |
| Department: | Computer Science |
| Source(s) of Funding: | URC/CRCG - Conference Grants for Teaching Staff |
| Start Date: | 04/2010 |
| Completion Date: | 04/2010 |
| Abstract: |
| N/A |
| List of Research Outputs |
| Chin F.Y.L., Ting H.F., Tsin Y.H. and Zhang Y., Online uniformly inserting points on grid, The 6th International Conference on Algorithmic Aspect in Information and Management (AAIM). 2010, 282-292. |
| Researcher : Lee PKK |
| Project Title: | International conference on slope engineering |
| Investigator(s): | Lee PKK |
| Department: | Civil Engineering |
| Source(s) of Funding: | Croucher Foundation - Conference / Seminars |
| Start Date: | 12/2003 |
| Abstract: |
| International conference on slope engineering |
| List of Research Outputs |
| Yeung A.T., Ng T.S.T., Tham L.G. and Lee P.K.K., HKU's double professional civil engineering and law programme, Proceedings of the Institution of Civil Engineers - Management, Procurement and Law. 2010, 163(MP2): 77-85. |
| Researcher : Li VOK |
| Project Title: | Information technology for a 21st Century Hong Kong: an IT society with a strong value-added economy |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Matching Fund for Area of Excellence (AoE) |
| Start Date: | 01/2000 |
| Abstract: |
| To assist the transformation of Hong Kong into an IT society, and as a strong value-added economy within Asia, through active high-impact IT research and development, relevant technology transfer, and quality education for competitiveness. |
| Project Title: | Information Technology |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Seed Funding for Strategic Research Theme |
| Start Date: | 06/2008 |
| Completion Date: | 05/2011 |
| Abstract: |
| n/a |
| Project Title: | Heterogeneous Peer-to-Peer Networks |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | CAS - Croucher Funding Scheme for Joint Laboratories |
| Start Date: | 10/2008 |
| Abstract: |
| To identify the desirable characteristics of a novel Internet Protocol suited to a heterogeneous network an to P2P applications; to design and analyze such a novel Internet protocol; to design and analyze an algorithm for content distribution in heterogeneous P2P networks; to design and analyze an algorithm for sensor nodes in heterogeneous P2P networks. |
| Project Title: | Chemical-Reaction-Inspired Metaheuristic for Optimization |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Seed Funding Programme for Basic Research |
| Start Date: | 05/2009 |
| Completion Date: | 04/2010 |
| Abstract: |
| We encounter optimization problems in our daily lives and in research in various fields. Some of them are so hard that we can, at best, approximate the best solutions with (meta-)heuristic methods. However, the huge number of optimization problems and the small number of generally acknowledged methods mean that more metaheuristics are needed to fill the gap. We propose a new metaheuristic, called Chemical Reaction Optimization (CRO), to solve these hard problems. It mimics the interactions of molecules in a chemical reaction to reach a low energy stable state. The key is to develop a framework to map the physical characteristics of chemical reactions to a generic optimization problem. Then we need to develop a practical CRO Algorithm, and to demonstrate its effectiveness on solving real problems. |
| Project Title: | Low-cost Versatile Tracking Device and Technology for Logistic Applications |
| Investigator(s): | Li VOK, Yang G, Wong EC, Lai MCW |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Platform Research Projects - General Award |
| Start Date: | 10/2009 |
| Abstract: |
| The objective of this project is to develop a low-cost tracking device and positioning technology for logistics applications. The core technology to be developed in this project represents innovations in the four categories: 1. Positioning technologies 2. Communications technologies 3. Device technologies 4. Services technologies Based on the core technology, a versatile tracking device system that works seamlessly from outdoor to indoor will be developed; Logistics tracking applications for pilot implementation will be developed to verify the design and implementation of the tracking devices. Different communication and positioning technologies will be integrated to enable seamless tracking of logistics objects in the pilot implementations. The following pilot projects will be conducted with 3PL and LBS navigation vendor: 1. Multi-modal Cooperative Cargo Tracking on expensive consumer electronic products 2. Fleet Management in City Canyons for high-valued goods delivery |
| Project Title: | IEEE Globecom 2009 A Joint Design of Opportunistic Forwarding and Energy-Efficient MAC Protocol in Wireless Sensor Networks |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | URC/CRCG - Conference Grants for Teaching Staff |
| Start Date: | 11/2009 |
| Completion Date: | 12/2009 |
| Abstract: |
| N/A |
| Project Title: | Outstanding Research Student Supervisor Award 2008-2009 |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Outstanding Research Student Supervisor Award |
| Start Date: | 12/2009 |
| Abstract: |
| For recognizing, rewarding and encouraging exceptioal research achievements; and for strengthening the research culture of the University. |
| Project Title: | Low-cost Versatile Tracking Device and Technology for Logistic Applications |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Innovation and Technology Fund Internship Programme (LSCM) |
| Start Date: | 02/2010 |
| Abstract: |
| The objective of this project is to develop a low-cost tracking device and positioning technology for logistics applications. The core technology to be developed in this project represents innovations in the four categories: 1. Positioning technologies 2. Communications technologies 3. Device technologies 4. Services technologies Based on the core technology, a versatile tracking device system that works seamlessly from outdoor to indoor will be developed; Logistics tracking applications for pilot implementation will be developed to verify the design and implementation of the tracking devices. Different communication and positioning technologies will be integrated to enable seamless tracking of logistics objects in the pilot implementations. The following pilot projects will be conducted with 3PL and LBS navigation vendor: 1. Multi-modal Cooperative Cargo Tracking on expensive consumer electronic products 2. Fleet Management in City Canyons for high-valued goods delivery |
| Project Title: | Smart Grid Telecommunication Infrastructure |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Seed Funding Programme for Basic Research |
| Start Date: | 05/2010 |
| Abstract: |
| The existing power grid infrastructures in many countries are primarily based on technologies that have been developed many decades ago under the producer-consumer model that power will be generated at major power plants and distributed to consumers. Such infrastructures are ageing and in many cases have reached their full capacities. In addition, with the increasing popularity of renewable energy sources such as solar and wind power, demand response, and smart electrical appliances, the producer-consumer model may no longer hold, and the supply and demand for electricity become more dynamic. Recently, many countries have announced research programs to re-vitalize such infrastructures using modern technologies such as communication, sensor network, power electronics, and control technologies so that the power grid can be managed more effectively, and to cope with such complexities as fluctuating energy sources and consumers. In this proposal, we focus on the telecommunication infrastructure. In particular, we propose to develop the technologies for a secure and efficient information infrastructure to ensure the safety and reliability of the smart grid. This project has two key objectives: 1. Integration of information technologies and electric energy delivery technologies to design innovative methodologies to manage and control the electric delivery network. 2. Development of a reliable communication infrastructure which is capable of secure and timely delivery of data to ensure real-time monitoring and control of the smart grid. |
| Project Title: | Low-cost Versatile Tracking Device and Technology for Logistic Applications |
| Investigator(s): | Li VOK |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Innovation and Technology Fund Internship Programme (LSCM) |
| Start Date: | 06/2010 |
| Abstract: |
| The objective of this project is to develop a low-cost tracking device and positioning technology for logistics applications. The core technology to be developed in this project represents innovations in the four categories: 1. Positioning technologies 2. Communications technologies 3. Device technologies 4. Services technologies Based on the core technology, a versatile tracking device system that works seamlessly from outdoor to indoor will be developed; Logistics tracking applications for pilot implementation will be developed to verify the design and implementation of the tracking devices. Different communication and positioning technologies will be integrated to enable seamless tracking of logistics objects in the pilot implementations. The following pilot projects will be conducted with 3PL and LBS navigation vendor: 1. Multi-modal Cooperative Cargo Tracking on expensive consumer electronic products 2. Fleet Management in City Canyons for high-valued goods delivery |
| Project Title: | Energy Management System for Smart Homes and Smart Buildings |
| Investigator(s): | Li VOK, Yang G, Yu J |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Seed Funding Programme for Applied Research |
| Start Date: | 06/2010 |
| Abstract: |
| An energy management system (EMS) is a system to monitor, control and optimize the performance of energy generation, transmission, distribution, and consumption. EMS plays a key role in enhancing energy reliability, stability and sustainability, and decreasing the power consumption and greenhouse gas emissions. In this project, we will focus on the energy consumption side and develop an EMS for smart homes and smart buildings. The major challenge of such systems is how to handle the problems of heterogeneity, distribution, and dynamicity. We shall propose and develop a low-power and low-cost heterogeneous wireless sensor network to address the problems of heterogeneity and distribution; and develop novel context-aware intelligence to handle the dynamicity. The proposed system shall offer economic benefits to the end users and utilities. Meanwhile, it shall also generate substantial social benefits. |
| List of Research Outputs |
| Li G. and Li V.O.K., A Queue with Multiple Stable Regions, 25th UK Performance Engineering Workshop (UKPEW 2009), Leeds, U.K., 2009.. 2009. |
| Xu J., Yang G. and Li V.O.K., A Population Dynamics Model for Data Streaming over P2P Networks, The Fifteenth International Conference on Parallel and Distributed Systems (ICPADS'09), Shenzhen, China, Dec. 81, 2009.. 2009. |
| Researcher : Tan ST |
| Project Title: | Heterogeneous solid modeling using materially defined geometric entities |
| Investigator(s): | Tan ST |
| Department: | Mechanical Engg |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 04/2005 |
| Abstract: |
| To extend and enchance the traditional homogeneous solid modeling methods by incorporating material information in the 1D, 2D and 3D geometric entities. Such a representation guarantees a more flexible material variation to be defined throughout the 3D space and the user's design intent can be intuitively captured. Moreover, a range of heterogeneous objects which are difficult or unable to be defined with existing methods can be represented. Unlike existing heterogeneous modeling schemes, this proposal defines the 1D and 2D heterogeneous geometric entities first and then hierarchically builds complex 3D solids from the lower level heterogeneous entities. To represent heterogeneous solids uniformly and generically, a Heterogeneous Feature Tree (HFT) is introduced and a material evaluation algorithm is proposed to dynamically determine or define the material information at a point. |
| Project Title: | Computer aided modeling of porous objects |
| Investigator(s): | Tan ST |
| Department: | Mechanical Engg |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2007 |
| Completion Date: | 12/2009 |
| Abstract: |
| This proposal aims to investigate the problems of porous objects modelling with a view to applying the models to some useful applications. For example, in Bio-CAD like bone implants where the bio-compability of the implants with human tissues is of huge concern. In drug delivery problems where the path and boundaries of the injected fluids are greatly influenced by the distribution of the pores. In the design of filters where the sizes and shapes of the pores are of paramount importance. |
| Project Title: | Voice enabled CAD modeling |
| Investigator(s): | Tan ST |
| Department: | Mechanical Engg |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2009 |
| Abstract: |
| 1. To effect a faster and efficient CAD modeling process through voice commands. A very useful capability to have would be: "Chamfer Edge A of Part B" instead of conventionally and tediously driving the mouse to do this simple process on individual edges. 2. To investigate voice based approaches to boost the modeling efficiency as well as the overall productivities; 3. To investigate voice based approaches to improve the ease of use and user satisfactions; 4. To develop and implement a novel generation of voice enabled CAD system. |
| Project Title: | Adaptive mesh generation for the finite element analysis of heterogeneous objects |
| Investigator(s): | Tan ST |
| Department: | Mechanical Engg |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2010 |
| Abstract: |
| 1) To investigate the influences of the mesh qualities on the solution accuracies and computational overheads in FEA of heterogeneous objects; 2) To provide a new adaptive meshing strategy which enables the material heterogeneity to be taken into account in the finite element analysis; 3) To introduce a new concept called “Material Curvature” (MC) to reflect and characterize the local material heterogeneities, the material curvature will be used to mimic and extend the classic local curvatures based adaptive meshing scheme; 4) To propose a new mathematical model in which the node spacing function [26] is modelled as the function of both the geometries as well as the material distributions; 5) To provide a set of algorithms to perform adaptive meshing of heterogeneous objects. Such algorithms should require minimum human supervision or manual intervention; 6) To test the feasibility and efficacy of using the generated mesh in contemporary FEA packages. |
| List of Research Outputs |
| Kou X. and Tan S.T., An XML implementation for data exchange of heterogeneous object models, In: Xun Xu and Andrew Y. C. Nee, Springer Series in Advanced Manufacturing, Advanced Design and Manufacturing based on STEP. London, Springer, 2009, 419-438. |
| Researcher : Tham LG |
| Project Title: | Instrumentation of Rock-socketed Steel H-piles |
| Investigator(s): | Tham LG |
| Department: | Civil Engineering |
| Source(s) of Funding: | Architectural Services Department - General Award |
| Start Date: | 03/2007 |
| Abstract: |
| To Investigate the load transfer mechanism of rock socketed H piles; to determine the bond strength between the H-piles and the grout; to determine the temperature in the grout body by thermo-couples. |
| Project Title: | Large Direct Shear Tests of Soil Blocks with Roots |
| Investigator(s): | Tham LG, Kwong AKL, Lee PKK |
| Department: | Civil Engineering |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2008 |
| Completion Date: | 12/2009 |
| Abstract: |
| (1) Be able to quantify the relative contribution of shearing resistance from the roots and from the soil so that parameters can be used in the practical design. (2) Be able to measure the tensile strength of the roots and the change in moisture content in a vertical profile of the combined root and soil system. (3) Be able to accurately measure the depth and lateral extent of the roots to assess whether the roots of the Vetiver grass can penetrate and anchor below the potential sliding surface.(4) Be able to evaluate the reduction of surface erosion due to planting of the vegetation. |
| Project Title: | Full-scale Field Testing of Massive Landslide in Liquefiable Loess to Investigate the Change in Pore Water Pressure and Collapse Mechanisms Triggered by Water Infiltration |
| Investigator(s): | Tham LG, Kwong AKL, Lee PKK |
| Department: | Civil Engineering |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 10/2008 |
| Abstract: |
| 1. To enhance our understanding of the failure mechanisms of landslides involving liquefiable soil, the debris of which travels in a very long run out distance. 2. To measure the migration of the wetting band and the change in positive or negative pore water pressure within different parts of the soil mass when subjected to artificially induced rainfall. 3. To capture the surface and internal movement of the soil mass when it is subjected to a change in positive or negative pore water pressure within different parts of the soil mass. 4. To compare the stress path measured in the field with that from the laboratory. 5. To numerically model the movement of the soil mass when the positive or negative pore water pressure within different parts of the soil mass are captured in the field. |
| Project Title: | Unified modelling of movement of saturated and unsaturated slopes |
| Investigator(s): | Tham LG, Cheuk JCY |
| Department: | Civil Engineering |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 01/2009 |
| Abstract: |
| 1. To investigate fundamental material behaviour, including yielding, dilatancy and water retention capability, of unsaturated decomposed soils during wetting, drying and shearing 2. To develop a unified constitutive model for both saturated and unsaturated decomposed soils 3. To implement the unified constitutive model in a numerical code for solving boundary value problems 4. To identify soil response and deformation mechanisms using the unified constitutive model |
| Project Title: | 17th International Conference on Soil Mechanics and Geotechnical Engineering Effect of surface and sub-surface infiltration on the behaviour of loose fill slopes |
| Investigator(s): | Tham LG |
| Department: | Civil Engineering |
| Source(s) of Funding: | URC/CRCG - Conference Grants for Teaching Staff |
| Start Date: | 10/2009 |
| Completion Date: | 10/2009 |
| Abstract: |
| N/A |
| Project Title: | Green Slope Engineering for Hong Kong |
| Investigator(s): | Tham LG, Hau CH, Yan RWM |
| Department: | Civil Engineering |
| Source(s) of Funding: | Collaborative Research Fund (CRF) - Group Research Project |
| Start Date: | 06/2010 |
| Abstract: |
| To investigate and understand the ecological role of vegetation cover and tree root systems including live poles in the stability and rehabilitation of slopes; To test and measure the tensile and shear strength of selected live poles; To carry out centrifuge model tests to investigate stability and failure mechanisms of live pole reinforced soil slopes under various rainfall and ground water conditions; To evaluate the reliability of bioengineered slopes based on observed performance and formulate plans for quality assurance of vegetated slopes; To explore the possibility of using the “integrated bioengineered live slope cover” developed to replace existing shotcrete cover; To develop innovative and reliability-based preliminary design guidelines for integrated, environmentally friendly bioengineered slopes in Hong Kong. |
| List of Research Outputs |
| Yeung A.T., So T.C., Kwong A.K.L., Tham L.G. and Zhao W.B., Field-scale constructability evaluation of underwater vacuum preloading, Geomechanics and Geoengineering: An International Journal. 2009, 4(3): 245-252. |
| Zhou Y., Cheuk J.C.Y. and Tham L.G., An embedded bond-slip model for finite element modelling of soil-nail interaction, Computers and Geotechnics. Elsevier, 2009, 36: 1090-1097. |
| Zhou Y., Cheuk J.C.Y. and Tham L.G., Deformation and crack development of a nailed loose fill slope subjected to water infiltration, Landslides. Springer, 2009, 6. |
| Zhou Y., Cheuk J.C.Y., Xu K. and Tham L.G., Effect of surface and sub-surface infiltration on the behaviour of loose fill slopes, the 17th International Conference on Soil Mechanics and Geotechnical Engineering. Millpress Science Publishers, 2009. |
| Researcher : Wu EX |
| Project Title: | Magnetic resonance imaging for biomedical research |
| Investigator(s): | Wu EX |
| Department: | Engineering Faculty |
| Source(s) of Funding: | Seed Funding for New Staff |
| Start Date: | 02/2004 |
| Abstract: |
| To develop and acquire the basic and necessary software and hardware required for the MRI research at HKU. |
| Project Title: | Magnetic Resonance Measurement of Heart and Liver Iron |
| Investigator(s): | Wu EX |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | The National Institute of Diabetes and Digestive and Kidney Diseases |
| Start Date: | 11/2006 |
| Abstract: |
| 1. Implementation and optimization of projection-reconstruction, gradient- and spin-echo imaging sequences to map T2 and T2* in test phantoms. The work initially will be performed at 7 Tesla for testing and then implemented for clinical imaging at 3 Tesla. This component of the research work will also include development of necessary software toolkits for image data analysis. 2.Optimization of clinical protocols at 3 Tesla for T2 and T2* measurements using projection-reconstruction, gradient- and spin-echo sequences in the anterior pituitary, pancreas and gonads. 3. Estimates of iron deposition in the anterior pituitary, pancreas and gonads using the optimized MRI protocols will be compared with the results of clinical evaluation of endocrine function in a group of thalassaemia patients with a wide range of body iron burdens. |
| Project Title: | Cell labeling for In Vivo MRI Monitoring after Transplantation in Cell Based Therapies |
| Investigator(s): | Wu EX |
| Department: | Engineering Faculty |
| Source(s) of Funding: | Small Project Funding |
| Start Date: | 01/2007 |
| Abstract: |
| In vivo monitoring of stem cells after grafting is essential for a better understanding of their migrational dynamics and differentiation processes and of their therapeutic potential. High-field magnetic resonance imaging (MRI) is potentially capable of tracking transplanted stem cells, and characterizing resulting anatomical, physiological and functional recovery in vivo, intact, and with high spatial resolution. We propose to develop such cellular imaging methodology on a 7 Tesla MRI scanner by (i) designing various techniques to label cells in vitro and quantitatively monitoring their in vivo distribution and activity after transplantation in stem cell therapy in rat stroke model; (ii) characterizing the therapeutic outcome in terms of anatomical structures and physiological functions using various MRI methods. |
| Project Title: | International Bioiron Society (IBIS) 2007 Meeting MRI CHARACTERIZATION OF FERRITIN-LIKE AND HEMOSIDERIN-LIKE IRON |
| Investigator(s): | Wu EX |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | URC/CRCG - Conference Grants for Teaching Staff |
| Start Date: | 04/2007 |
| Abstract: |
| N/A |
| Project Title: | Thalassaemia Major: A new MRI method for monitoring heart and liver iron deposition |
| Investigator(s): | Wu EX, Au WY, Ha SY |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Children's Thalassaemia Foundation - General Awards |
| Start Date: | 09/2007 |
| Abstract: |
| To develop a new magnetic resonance imaging (MRI) method for detection and monitoring of heart iron deposition in patients with thalassaemia major and other forms of iron overload. |
| Project Title: | Thalassaemia major: a new MRI method for detection and monitoring of heart and liver iron deposition |
| Investigator(s): | Wu EX, Ha SY, Khong PL, Tse HF |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 09/2007 |
| Abstract: |
| To develop and optimize new MRI pulse sequences to separately measure ferritin and hemosiderin iron by their distinctive effects on CPMG signal decay in phantoms containing water soluble nanometer-sized (ferritin-like) iron particles and water insoluble micron-sized (hemosiderin-like) iron particles and validate the MRI method by studies ex vivo of heart and liver samples from patients with iron overload in which ferritin and hemosiderin iron concentrations will be determined by biochemical measurement; to assess the new MRI determinations of tissue ferritin and hemosiderin iron in cross-sectional and prospective longitudinal studies of cardiac and hepatic function in thalassaemia patients with iron overload. |
| Project Title: | MR Study of High-order Water Molecule Diffusion in Biological Systems |
| Investigator(s): | Wu EX |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Small Project Funding |
| Start Date: | 12/2007 |
| Abstract: |
| Diffusion tensor magnetic resonance imaging (DTI) has great potential to provide detailed information regarding central nervous system (CNS) tissue morphology and pathology. Often, the results of DTI studies are presented using summary parameters such as apparent diffusion coefficient (ADC) or fractional anisotropy (RA) that allow a simplified expression of water diffusion characteristics. While these summary parameters are convenient and are often highly correlated with disease progression, they fail to capture the specific, directional information inherent in the full DTI experiment. This project aims to develop, evaluate and validate a new in vivo and non-invasive MR diffusion kurtosis imaging (DKI) technique to charaterize CNS tissue. The specific objectives are: 1. Develop and implement MR data acquisition sequences. 2. Comprehensive analysis of the 2nd-order (conventional DTI approach) and 4th-order diffusion tensors. 3. Correlation of MRI DTI and DKI images with histology. 4. Monte Carlo simulation of diffusion kurtosis characteristics. |
| Project Title: | 16th Scientific Meeting of International Society for Magnetic Resonance in Medicine (ISMRM) Relation of myocardial fiber structure with cardiac wall motion using DTI and MR tagging Myocardium structural remodeling with relation of infarct location and size in porcine model using DTI MR study of postnatal development of left ventricular myocardium structure and function in rats |
| Investigator(s): | Wu EX |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | URC/CRCG - Conference Grants for Teaching Staff |
| Start Date: | 05/2008 |
| Abstract: |
| N/A |
| Project Title: | 30th Annual International Conference of the IEEE Engineering in Medicine and Biology Society Magnetic Resonance Imaging of Migrating Neuronal Precursors in Normal and Hypoxic-ischemic Neonatal Rat Brains by Intraventricular MPIO Labeling Preliminary In Vitro Study of Ultrasound Sonoporation Cell Labeling with Superparamagnetic Iron Oxide Particles for MRI Cell Tracking |
| Investigator(s): | Wu EX |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | URC/CRCG - Conference Grants for Teaching Staff |
| Start Date: | 08/2008 |
| Abstract: |
| N/A |
| Project Title: | Manganese-enhanced MRI for In Vivo Detection of Neurodegeneration in Neonatal Hypoxic-ischemic Brain Injury |
| Investigator(s): | Wu EX, Khong PL |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 09/2008 |
| Abstract: |
| (1) Quantitative and longitudinal characterization of MEMRI, Mn-SOD and GS levels and Mn concentrations in two established neonatal rat H-I brain injury models (severe and mild H-I models): The purpose is to establish the spatiotemporal correlations between MEMRI measurements, enzyme levels and Mn levels; and (ii) assess the effect of Mn injection time and gradual clearance of Mn-SOD, GS and Mn in vivo; (2) Evaluation of MnDPDP for MEMRI in mild H-I model: The purpose is to experimentally evaluate MnDPDP, a clinically approved chelated Mn2+ contrast agent for liver MRI, for detection of Mn-SOD or/and GS activities in noncystic PVL model and assessment of any apparent toxicity. |
| Project Title: | Neuroimaging of Spontaneous Brain Activities in Anaesthetized Rodents |
| Investigator(s): | Wu EX |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Small Project Funding |
| Start Date: | 11/2008 |
| Abstract: |
| In this study, electrophysiologicalrecordings and resting-state fMRI measurements will be conducted in anesthetized rats upon different isoflurane gas concentrations at various ages. The blood oxygenation level-dependent signal fluctuations will be correlated with the EEG power variations of delta, theta, alpha, beta, and gamma rhythms to investigate the relationship between hemodynamic and electrical oscillations. |
| Project Title: | Diffusion Kurtosis Imaging For Improved Neural Tissue Characterization By Magnetic Resonance |
| Investigator(s): | Wu EX, Khong PL, Wu W |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | General Research Fund (GRF) |
| Start Date: | 09/2009 |
| Abstract: |
| 1) Implement and optimize our DKI method on a 7T rodent MRI scanner with a twice-refocused spin-echo sequence to minimize eddy current distortions, and to compute a complete set of DKI index maps using our directional kurtosis analysis protocol; 2) Evaluate our DKI method and analysis protocol by monitoring postnatal rodent brain development between postnatal day 0 and 360. Voxel-wise and ROI analysis will be performed to determine regional DKI index changes with time and to compare DKI with conventional DTI in detecting subtle microstructural alterations; 3) Evaluate our DKI method and analysis protocol by monitoring rodent brain aging longitudinally from postnatal year 1 to 2.5 with similar procedures and objectives. |
| Project Title: | 31st Annual International Conference of the IEEE Engineering in Medicine and Biology Society Gas-filled Microbubbles – A Novel Susceptibility Contrast Agent for Brain and Liver MRI |
| Investigator(s): | Wu EX |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | URC/CRCG - Conference Grants for Teaching Staff |
| Start Date: | 09/2009 |
| Abstract: |
| N/A |
| Project Title: | In Vivo MRI of Endogenous Stem/Progenitor Cell Migration in Developing Brains |
| Investigator(s): | Wu EX |
| Department: | Electrical & Electronic Engg |
| Source(s) of Funding: | Small Project Funding |
| Start Date: | 11/2009 |
| Abstract: |
| The general objective of the present study is to employ the in situ cell labeling approach to characterize the migration of the endogenous NSPs from the SVZ in the postnatal developing rat brains in normal and HI-injured developing conditions. We further hypothesize that the NSP migrating patterns in normal and HI-injured developing brains will differ and can be detected by serial high-resolution in vivo MRI in addition to postmortem immunohistochemical analysis. Such in vivo MRI analysis can improve our understanding of NSP behavior in the developing mammalian brains and its alterations during injuries. The specific aims are: 1. MRI Determination of Migrating NSPs, Migration Patterns and Histological Colocalization in the Normal Developing Brains; 2. MRI Determination of Migrating NSPs, Migrating Patterns and Histological Colocalization in the HI-Injured Developing Brains; 3. Evaluation of Alteration of Migrating Pathways in HI-Injured Brains in Response to Injury. |