Project Abstracts
| Project Leader | Project Title | Project Abstract |
|---|---|---|
Improving Sensitivity of Early Detection of AD via Multidimensional Analysis of Longitudinal MR Scans We propose to use recent Computational Anatomy (CA) algorithms from our group to develop novel multidimensional longitudinal biomarker for early detection of neuroanatomical change due to AD vis--vis normal aging. The overarching hypotheses for our proposal are that a) multidimensional biomarkers containing combined neuroanatomical measures from several structures at single time-point (baseline) and b) longitudinal multidimensional biomarkers additionally combining rate of change in neuroanatomical measures over time (follow-up scan compared to baseline) will offer superior sensitivity for early detection of AD than using neuroanatomical measures of individual structures separately at baseline alone. | ||
Study of Automata and its Applications to Number Theory and Algebra Finite-state automata play a fundamental role in theoretical computer science, but in recent years many advances in number theory, geometry, and algebra have been made by adopting an automaton-theoretic viewpoint. Just a few of their many applications are to noncommutative algebra, where they can often be used to find Groebner bases for finitely presented algebras; and to number theory, where they can sometimes be used to determine whether power series satisfy certain differential equations.
This project involves graduate students and visitors to IRMACS, who will both do research on these areas and hold seminars. IRMACS facilities will be used to hold weekly seminars and for undertaking computations.
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Problems in the Design & Analysis of Computer Experiments
Rapid growth in computer power has made it possible to study complex physical phenomena that might otherwise be too time consuming or expensive to observe. Scientists are able to adjust inputs to computer simulators (or computer codes) in order to help understand their impact on a system. Many such computer simulators require the specification of a large number of input settings and are computationally demanding. This project involves the design and analysis of computer experiments, with emphasis on the study of physics based on engineering simulators. Initial project goals include model calibration and integration of field data with simulator output. | ||
Explorations in Computational Number Theory Number theory is one of the oldest, deepest and most vibrant branches of modern mathematics. It centrally incorporates some of the most sophisticated and profound mathematical ideas that have been developed (witness the recent proof of Fermat's Last Theorem) and yet remains broadly useful in many areas of pure and applied mathematics. It is remarkable how often number theory comes to bear both in other areas of mathematics and in applications. A notable recent example is internet security whose protocols are based on number theoretic problems.
Number theory has historically been motivated by the study of properties of integers and solutions to equations in integers, but now iincludes many other aspects, each with its own flavour and viewpoints. Broadly speaking, these can be divided into Analytic, Algebraic, Diophantine, and Geometric aspects of Number Theory. Research in Number theory today often involves knowledge and expertise from areas such as Algebra, Algebraic Geometry, Analysis, Combinatorics, Probability Theory, Representation Theory, Topology. Connections to appplicable fields include Coding Theory and Cryptography.
At Simon Fraser University, we have a strong group in Number Theory which covers the spectrum of Number Theory. Together with the groups at the University of British Columbia and the University of Washington at Seattle, we form one of the largest groups of Number Theory Researchers in North America.
We maintain two active research seminars with UBC and UW which keep abreast of current developments in Number Theory. These are the SFU - UBC Number Theory Seminar and Pacific Northwest Number Theory Seminar. We also run a regular SFU Number Theory Study Seminar.
Our members are also active participants in the programs and initiatives of the PIMS and MITACS. | ||
Peter Borwein & Vahid Dabbaghian MoCSSy Program Crime is a complex phenomenon in society. It is influenced by many societal factors and constraints. These include, but are not limited to, the social networks of offenders and potential offenders, the awareness spaces of offenders and victims, the design of road networks and other urban infrastructure, prevailing policy decisions, land usage and zoning and technology. These influences impact the spatial and temporal distribution of crime in urban centres. This group is beginning to incorporate these influences using agent-based modelling and cellular automata models to consider the complexity of crime patterns in urban centres. | ||
Institute for Canadian Urban Research Studies (ICURS) ICURS focuses on: crime reduction policy, crime analysis, and computational criminology.
ICURS blends expert knowledge in government departments with leading edge theory and research in universities. Its goal is to work thematically across the disciplines of criminology, computing science, geography, economics, and applied mathematics to make advances in understanding and modeling of the complex urban environment, and with these models better understand how to improve approaches to crime reduction and the use of informatics in criminological research. | ||
Sequence Analysis of Germline and Expressed Immunoglobin Genes
One of the responses of the body to infection is to produce antibodies to foreign antigens (mostly viruses and bacteria) have evolved to produce a very diverse antibody response to the huge diversity of pathogens to which we are exposed. The first step in the creation of antibody diversity is the recombination of various V, J, and D gene segments within the genome of a developing B cell to produce a functional antibody gene. The second step occurs when that B cell's antibody gene is further diversified by somatic mutation. In this manner, B cells producing the tightest-binding antibodies are selected by antigen, with the selection being based on both the gene segments that the B cell uses, and the somatic mutations that arise in that B cell clone.
More and more sequences of expressed antibody genes are being examined in patients with specific diseases. Based on these sequences, researchers have observed distinct patterns of V-gene usage and somatic mutation. For example, specific types of somatic mutations are characteristic of autoimmune diseases, whereas HIV-1 infection may be characterized by the use of certain families of V-Genes.
This more sophisticated and statistically sound understanding of the patterns of V-gene usage and somatic mutation is critical to both vaccine development and understanding autoimmune diseases. | ||
Bioinformatics for Health Research Bioinformatics research has become increasingly interdisciplinary as it draws further upon areas within computer science, software engineering, mathematics, statistics, physics, and a wide range of biological and other sub-disciplines. The Bioinformatics for Health Research program involves a collection of interdisciplinary research projects that promote student training in this area and facilitates interactions between researchers from different backgrounds in the computational, biological and other related sciences. This novel program is the first of its kind in Canada and was the highest ranked CIHR (Canadian Institutes for Health Research) grant in its category. It involves a combination of 4-8 month subprojects, longer graduate student thesis projects, and a series of meetings to facilitate interaction. All research is centered around developing novel bioinformatics approaches to improve human health. There is a focus on new algorithm development for analysis of genomic (all genes in an organism) and proteomic (all proteins in an organism) data from humans, model animals, and infectious disease microorganisms.
Students in this program come from diverse backgrounds in the applied and natural sciences and it is felt that only through frequent interaction with each other will these students truly be able to benefit from their interdisciplinary knowledge. However, currently the students in this funded program have no 'home'. There has therefore been a strong endorsement by the Director of this program, Steven Jones (BCGSC and adjunct of MBB), the SFU co-Director of this program, David Baillie (MBB), and members of the program committee, that these students be housed in the IRMACS facility as 'regular' members. It is hoped that a bioinformatics core centered around this program and located in IRMACS will benefit greatly from interaction with other researchers in this interdisciplinary facility. These students, with their own interdisciplinary background will also hopefully benefit other researchers in the facility, and may help stimulate further collaborations within different research groups at SFU. | ||
Ramsey Theory Working Group Ramsey Theory is a cohesive sub-discipline of combinatorics. The theme of Ramsey Theory is that "complete chaos is impossible." Or, one could say that Ramsey Theory is "the study of unavoidable regularities in large structures."
There are applications of Ramsey Theory to number theory, geometry, topology, set theory, logic, ergodic theory, information theory, and theoretical computer science. (A recent survey article on applications of Ramsey Theory has a bibliography of 252 items.)
Two of the largest branches of Ramsey Theory start with either "Ramsey's Theorem" on the one hand, or "van der Waerden's Theorem on Arithmetic Progressions" on the other. These two branches sometimes overlap, but a great number of results can be placed on one branch or the other.
We are working on problems that grow out of van der Waerden's Theorem, the simplest form of which is the following statement: For every positive integer k there exists a smallest positive integer w = w(k) such that if {1, 2, ?, w} is partitioned into two parts, in any way whatsoever, then at least one of the parts contains a k-term arithmetic progression, that is, a subset of the form {a, a+d, a+2d, ?, a+(k-1)d}.
The only known values of w(k) are w(1)=1, w(2)=3, w(3)=9, w(4)=35, w(5)=178.
In 1999, Ron Graham gave Timothy Gowers a "reward" of 1000 USD for showing that w(k) < 2^2^2^2^2^(k+9). (The notation here is x^y = x y, and x^y^z = x^(y^z), so Gowers's bound is an exponential tower with 6 levels.) This bound, which may seem large, is tiny compared to the previous best known bounds. Gowers received a Fields Medal in 1998.
The true rate of growth of the function w(k) is one of the holy grails of Ramsey Theory, and Ron Graham now offers 1000 USD for a proof that w(k) < 2^(k^2).
We are interested in variations on van der Waerden's theorem in which one restricts the type of partitions allowed (a weakening of van der Waerden's theorem), or one restricts the allowable set of ?d?s? in the sets {a, a+d, a+2d, ?, a+(k-1)d} (a strengthening of van der Waerden's theorem), or combinations of these and other variations. Here one is interested in establishing the existence of some function w?(k) analogous to the function w(k) above, and/or upper and lower bounds on the function w?(k). One may also replace the set of arithmetic progressions by a smaller or larger or completely different set. Of course, one may also partition the underlying possibly infinite set into more than 2 sets, and even into infinitely many sets. | ||
Combinatorial Models of Synteny Conservation in Genomes Genomic rearrangements - reversals, transpositions, deletions, insertions, duplications, translocations, among others - are large-scale evolutionary events that disrupt gene order along chromosomes. The computational analysis of gene orders, their structure and their evolution relies on combinatorial models and algorithms designed in terms of sequences of signed. The last 15 years have seen a wealth of research in this field, which provided widely used computational tools as well as new insights on the evolution and structure of several sets of genomes. The proposed program is centered on detection of con served gene clusters, the assignment of evolutionary relations in the presence of multigenes families and the computation of evolution hypothesis. Gene clusters, like operons in prokaryotic genomes, are fundamental functional genomic elements, that are characterized, among others, by conserved gene content and order, up to local rearrangements sometimes. Detecting some clusters is a difficult problem with applications in very applied domains, like pathogenomics. This part of the project aims at designing methods to detect such clusters that will (1) detect highly rearranged clusters, (2) discriminate between conserved clusters due to evolutive pressure and conserved clusters due to phylogenetic proximity and (3) be computationally efficient in order to process large datasets. Most algorithms aimed at analyzing genome rearrangements have been designed for signed permutations, which correspond to genomes with with trivial gene families. A recent approach to overcome this limitation assigns evolutionary relations between members of multigenes families, using a genes matching strategy in a parsimony framework. Our goal in this project is to develop a gene matching strategy that is not based on an evolutionary model but on the conservation of local synteny and also consider sequence alignments results used to define gene families and a statistical model of synteny conservation significance. The third main part of the proposed project deals with the analysis of gene order datasets produced using the methods developed in the two previous sub-projects for phylogenomic analysis, including computing gene order phylogenies, ancestral gene orders and statistics on genome rearrangements. Finally some attention will be given to the problem of generating "gene order" datasets for eukaryotic genomes, where genes only do not cover enough genome to be reliable markers. We will investigate two classical approaches, whole genome alignments and comparitive mapping technique, and a new method, based on virtual hybridation. Our approach for most of the above problems will rely on sound and well understand combinatorial models for the analysis of signed permutations and sequences, like, but not limited to, common intervals and max-gap clusters. An important focus will be on designing and implementing efficient algorithms based on these models. | ||
My Own Bits (MOB) "My Own Bits" (MOB) is an incubation project that bridges between Cryptography, Distributed Storage technology and highly-scalable operational databases. The objective of this project is to produce a platform that empowers individuals with full control over the flow of sensitive information on the internet. | ||
Human Evolutionary Studies Programme Over the last 150 years biology has been transformed by the adoption of Darwinian evolutionary theory to such an extent that, as the well-known geneticist Theodosius Dobzhansky once put it, "nothing in biology makes sense except in the light of evolution". The extension of Darwin's insights to humans has been halting and controversial. This is particularly the case for human cognition and behaviour. However, we have now reached a point where the utility of such research can no longer be denied. It is now clear that Darwinian theory can be productively applied to many of the puzzles that scholars in the humanities and social sciences have long sought to explain, such as perception, thought and culture. Likewise, it has become increasingly apparent that Darwinian theory can shed new light on important social and health issues, including prejudice, interpersonal violence and schizophrenia. The purpose of the Human Evolutionary Studies Program (HESP) is to create an internationally- recognized research and training 'hub' that will simultaneously advance the integrated understanding of the body, mind, behaviour and social institutions of Homo sapiens within the framework of evolutionary theory, and maximize the contribution of SFU researchers to this important, dynamic and publicly visible field of research. HESP will accomplish these goals by fostering collaborative relationships among diverse SFU faculty, postdoctoral fellows and graduate students, and between these individuals and researchers in other institutions; by supporting novel, highly interdisciplinary research projects; by providing undergraduates, graduate students and postdoctoral fellows with world-class training that transcends traditional disciplinary boundaries; and by disseminating the results of its research to academics in other fields, policymakers and the general public both directly and through the media.
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Advanced Computation, Collaboration & Visualization Lab (HPC/CV)
The HPC@SFU and WestGrid mandates are to provide computational, visualization and collaboration capabilities to scientists at the host university (SFU) and in WestGrid's case at its partner organizations (UBC, TRIUMF, UoA, UoC, UoLethbridge and Banff). Our goal in creating this lab is to provide a space for users from a wide range of disciplines to be able to explore the use of computation, collaboration, visualization technologies in their research projects. The lab will provide access to both technological resources (HPC, collaboration and visualization technologies) as well as expertise in these areas in order to help develop the use of these technologies.
Westgrid is deploying a set of large scale and desktop visualization technologies in the lab, including a large screen plasma display with a SmartBoard overlay, a high resolution (9 mega-pixels) display, and a number of desktop auto-stereoscopic displays. These display devices will be driven by high end commodity graphics computers (provided by WestGrid) as well as the WestGrid visualization supercomputer that is located at SFU. This lab complements (but does not duplicate) the capabilities of the IRMACS Presentation Studio. The lab will also be AccessGrid enabled, allowing for rich collaborative interaction from remote sites. The lab space would be used as a collaborative visualization lab, with space for the collaboration and visualization technologies described above as well as work space for research group members. The lab will provide access to the expertise in HPC, collaboration, and visualization that WestGrid and HPC@SFU provide to SFU researchers. The goal for this lab is for it to become a focal point for computation, collaboration and visualization research at SFU.
The lab will be linked to other similar research labs across the campus (the GRUVI lab in CS, the CoLab in mathematics, and the interaction lab at SFU Surrey) as well as other related labs across the country (the Mutual Media Lab at NRC in Ottawa, the NRC lab in Moncton, Jon Borwein's D-Drive lab at Dalhousie University in Halifax and the other WestGrid labs at UBC, Banff, UoA, UoC and Lethbridge). The HPC/CV lab will support research projects in a wide range of disciplines including physics, mathematics, chemistry, computer science, education, and the performing arts. | ||
Stereoscopic Cinematography State of the art cinematography has recently evolved to include stereoscopic display as an important medium. This project takes advantage of the cinematography expertise and the stereographic technologies available at the IRMACS Centre to explore this new cinematographic medium. The Stereoscopic Cinematography (SC) project is exploring the cinematographic (framing techniques, focal issues, camera movement, editing methods), the technical (convergence, inter-axial distance, and their interaction), and display aspects (screen size/distance, active vs passive, stereo disparity) of stereoscopic cinematography. | ||
New Paths to Treatment of Psychiatric Disorders and Cancer through Evolutionary Medicine Evolutionary medicine is a rapidly-emerging field that applies tools from evolutionary biology to explore the genetic basis of human disease. The project will include a community of evolutionary biologists that will comprise the first research team dedicated to applying theories of evolutionary biology to the massive amounts of genomic data being generated on human disease genes. The purpose will be to discover innovative ways of treatment and prevention. This project will concentrate on two highly-heritable sets of diseases: (1) mental disorders and (2) cancer. Next generation sequencing technology is generating vast amounts of genome-wide data that will be analyzed from the viewpoint of evolutionary biology in two ways. First, existing, publicly available data sets will be used to determine the degree to which disease-associated polymorphisms occur in genomic regions that exhibit evolutionary signatures of natural selection. Second, these data sets will be used to develop a new database of positively selected chromosomal regions within disease-related genes, because such regions can be inferred to be functional on the basis of evidence of natural selection. Both of these approaches will use the power of evolutionary biology to discover new candidates for disease-associated genes | ||
Visual Analytics Research: VARLab & SCIENCE Lab Whether the cause is an epidemic, natural disaster or an act of terrorism, accurate prediction of risks, timing, and consequences of destructive events will prevent loss of life and damage to property and natural resources. We are part of a multinational effort to develop visual analytics (VA), information and communication technology designed to aid skilled human decision-makers to recognize potential threats, make strategic and operational decisions, and to communicate with field workers and policy makers to coordinate response to potential and evolving threat situations. Our interaction science approach begins by understanding the user's perceptual, cognitive and enactive abilities. We then design and test VA environments to optimize the quality of decisions by supporting the perceptual, cognitive and enactive processes that give rise to them. We propose to integrate the work of Canadian industry and academic researchers with our existing multinational collaboration on VA.
In collaboration with partners in Canada and abroad, we will address decisions made by analysts, communication with field workers and coordination with government policy makers to insure that accurate and timely decisions are made throughout the chain of command.
For students this will provide fundingto participate in this cross-border collaboration on VA and interaction science, to work with their counterparts in the US and internationally.
For our Canadian industry partners this will provide transfer of knowledge from our interaction science and visual analytics research, opportunities to hire highly qualified students, international collaboration on the development of the next generation of VA applications from the best labs across the globe, and valuable contacts with potential clients for Canadian technology and consulting services brokered through our US and international government and industry partners. | ||
Conservation Connections: Using Evolution to Guide Conservation Priorities Over 500 species of Canadian wildlife are officially at risk of extinction. The limited resources that society has to apply to conservation efforts demands efficiencies and prioritization techniques. The Conservation Connections project will support Canada's leading role in conservation biology by developing new data management and modeling techniques to help identify, organize, and track species of greatest concern in Canada. We have chosen to develop our prototype tools using the world's sharks and rays: N. Dulvy is the International Union of Conservation Networks (IUCN) co-chair for this group of charismatic megafauna. Though phylogenetic data are critical both for setting conservation priorities and for predicting species vulnerability, no current conservation database explicitly incorporates such data. Our project will harness existing taxonomic databases (ubio.org) to National Centre for Biotechnology Information (NCBI) genomic data and graft these outputs to 'known' backbone trees by adapting new methodologies, e.g., from medical genomics and supertree approaches . This dynamic phylogenetic framework will form the core of a world-wide, freely accessible conservation scientific gateway for sharks and rays. This project will allow the creation, curation, visualization and manipulation of complex and data-rich taxonomic, systematic, threat driver, map (working with the Map of Life Team) and relevant ecological data for all 1095 species of chondricthyan fishes (sharks, rays, and skates), and link these to a novel dynamic phylogenetic structure (a prototype scientific gateway is available via the IRMACS website). This approach will change the way phylogenies are integrated with ecological, morphological, genomic and conservation data, and to our knowledge is a unique application of phylogenetic information in a dynamic environment, extensible to all endangered Canadian species. | ||
Multifractals, Scale Invariance and Financial Risk Management The primary objective of this research program is to obtain a deeper understanding of the underlying multifractal nature of financial time series and develop scale invariant models of financial markets. A scale invariant environment is a precursor in our understanding of financial markets and proper management of financial risks. The proposed research program will be carried out through the study of the underlying stochastic underpinnings of high frequency financial time series with a particular emphasis on its multifractal properties and the principle of scale invariance. The findings of this research program will contribute towards the identification, modelling and testing techniques in the understanding of the underlying dynamics of financial markets. | ||
Software Technology Lab Abstract:
Software technology builds on math, science and engineering. Systems design is a creative activity calling for abstract models that facilitate reasoning about the key system attributes (desired requirements and resulting properties) so as to ensure that these attributes are properly established prior to actually building a system. Such abstractions are best understood in terms of discrete mathematics and computational logic. Mathematical precision is essential for systematically analyzing blueprints of a system design to uncover and eliminate design flaws and weaknesses that often go unnoticed otherwise.
Research and development at SFU's Software Technology Lab aim at bridging the gap between formal and empirical approaches by improving the practicability of applying formal methods and computational tools to challenging problems in high level design of distributed, embedded and mobile systems in a variety of application contexts. Beyond classical systems design, we also engage in interdisciplinary and cross-disciplinary research in computational criminology, distributed information fusion, public safety and security, and social networks. | ||
Statistical Methods for Association Studies of Complex Genetic Disorders A single gene can be solely responsible for certain genetic disorders. For example, only people who carry two defective copies of the CFTR gene develop cystic fibrosis. By contrast, complex genetic disorders such as diabetes and cancer likely involve a number of genes that increase susceptibility, and act in conjunction with lifestyle and environmental exposures to increase risk for developing disease. To tackle complex disorders, researchers have turned from studies of families to studies of populations. Population association studies are increasingly reliant on genetic markers known as single nucleotide polymorphisms (SNPs) for mapping of susceptibility loci in candidate regions. While analysis of trait associations with alleles of single SNPs is useful, it ignores the potential for extra information from joint consideration of multiple linked SNPs on a haplotype. Simulation studies have shown that SNP haplotypes can provide more information than alleles of single SNPs for identifying and locating genes influencing complex traits. Indeed, SNP haplotypes have already proven useful in locating susceptibility genes for complex diseases such as Crohn's disease. However, current cost-effective genotyping technologies are only capable of identifying the two alleles present at a locus for a given individual, without specifying which of the two chromosomes each allele is derived from. Thus, when an individual is heterozygous at two or more SNPs and no family information is available, haplotypes cannot be determined unambiguously and haplotype phase is said to be unknown.
Investigators often use statistical methods to infer haplotypes of unknown phase and treat the resulting reconstructions as known in subsequent association analyses. This two-stage strategy ignores uncertainty in haplotype reconstructions and can therefore lead to biased estimates of associations, overly optimistic assessments of precision, and potential errors in interpretation. The proposed research develops improved biostatistical methods that account for haplotype uncertainty in analyzing these disease associations. The new techniques will reduce inaccuracies associated with previous methods and will be applied to data from ongoing studies with collaborators. The analytic tools that are being developed should enable researchers to better evaluate genetic and environmental risks for conditions such as diabetes, cancer and asthma, and find the underlying genes. The knowledge gained can help with devising more effective treatment and prevention strategies for these conditions. | ||
Population Genomics of Sea Stars We study the evolution of sex in the ocean. We use sea stars as a model system for analyzing population genetic variation and how that variation is shaped over evolutionary time by differences among species in mate selection and gene flow. New methods in this work use high-throughput sequencing methods to discover new genes expressed on sea star sperm and egg surfaces, and to analyze the pattern of molecular evolution of those genes compared to other parts of the genome. We use IRMACS computational and bioinformatics resources in those analyses. | ||
Low Field Magnetic Resonance Imaging We are interested in novel techniques of magnetic resonance imaging (MRI), in particular low field imaging using Helium-3 gas which may provide a powerful new tool for the study of lung physiology and disease. Our research involves in-vivo MRI studies as well as inquiry into the basic physics of nuclear magnetic resonance (NMR). We also dedicate significant effort to the design and construction of specialized hardware needed to perform low field MRI and NMR. We collaborate with researchers in radiology, physics, and engineering from Canada and abroad. | ||
Magnetic Nanostructures As the Director of the Surface Physics Laboratory (SPL), which is part of the Pacific Center for Advanced Materials and Microstructures (PCAMM), I have been involved in the study of magnetic nanostructured materials. The study of ultrathin metallic nanostructures has resulted in a wide range of new phenomena that are attractive to scientists working in basic aspects of low dimensional systems and to materials. A new approach in electronics has emerged that is based on the spin orientation of high density electron carriers in metals. This discipline is coined "spintronics".
Progress in understanding the properties of magnetic nanostructures and spintronics requires a thorough analysis of the structural and magnetic properties and spin dependent electron transport at metal/metal, metal/oxide, metal/semiconductor interfaces. In our effort we have tried to employ high quality crystalline epitaxial systems where one can compare experimental results with theoretical models allowing one to reach a better understanding of the underlying physical principles.
Research interest has shifted increasingly from the static to the dynamic properties of magnetic multilayers. This is motivated by the fact that the switching time of magnetic hybrid multilayers. This is motivated by the fact that the switching time of magnetic hybrid multilayers used in mass data storage devices and magnetic random access memories (MRAM) is a real technological issue. It is currently of considerable interest to acquire a thorough understanding of the spin dynamics in the nano-second time regime. My group is involved in spin dynamics of magnetic nanostructures.
1. Spin current studies: The precessing magnetization acts as a peristaltic spin pump which transports the spin momentum away from the ferro magnet (FM). It is important to realize that one can create the transport of spin momentum without using electrical current. In magnetic bi-layers the second FM absorbs the spin current acting as a spin sink, and that allows one to transport spin information with the net electric charge. This represents a new approach to spintronics. Currently, we are working on detection of spin currents using magneto-optics.
2. Two magnon scattering by spin density waves: We are able to enhance the relaxation rates significantly by employment of a self assembled network of crystalline defects. This work is carried out on crystalline magnetic multilayers using Molecular Beam Epitaxy system. A self-assembled network of crystalline defects is achieved by using crystalline lattice mismatch between the films and variable chemical stochiometery. This materials modifications are attractive to memory elements employed in spintronics applications.
3. Spin dynamics at large precessional angles: The non-local damping depends on the angle of magnetization precession. The non-local spin transport is going to be used at SPL using a high power microwave system with a dielectric "puck cavity" and coplanar wavequides using intense magnetic pulses. Collaborations in this area include: Profs. J. Stohr, H. Siegmann, Stanford U and scientists from Stanford U., Lawrence Berkeley National Lab, Seagate and IBM. 30 GeV electronic pulses of 2-10 ps duration and 5um in diameter created by the Stanford Linear Accelator Center (SLAC) provide high intensity (several T) magnetic pulses for magnetization reversal studies of a new generation of ultrahigh density (>100 Gbits/in2) magnetic memory media. | ||
Graphs & Algorithms We investigate the boundary between computationally hard and easy graph theoretic problems, in the framework of constraint satisfaction problems and homomorphisms, as well as matchings and their generalizations. The role of special structure in the input graphs is highlighted, focusing on cases where the structure allows for certifying algorithms. | ||
Robert Hogg & Krisztina Vasarhelyi IMPACT - HIV: Interdisciplinary Modelling for the Prevention, Care and Treatment of HIV and Related Infections In collaboration with the BC-CfE, the CSMG is currently modelling issues critical to the HIV epidemic in Canada and elsewhere through its formation of the group entitled the Interdisciplinary Modelling for the Prevention, Care and Treatment of HIV (IMPACT-HIV). Because the HIV epidemic presents complex problems that require increasingly comprehensive and powerful methods, the IMPACT-HIV group relies on the broad range of expertise of its members in mathematical modelling and other analytical techniques as well as in the biological, clinical, epidemiological, social and operational aspects of the HIV epidemic to address these issues through a multidisciplinary approach. Currently, IMPACT-HIV focuses on three main research areas:
Mathematical modelling of the spread and control of HIV among injection drug users
Estimating HIV incidence and the proportion of undiagnosed HIV infections
Estimating the impact of expanding access to highly active antiretroviral therapy (HAART) on the utilization and costs of acute care services provided to individuals infected with HIV in British Columbia
Multiple methods are implemented in the modelling process in each area, including analytical methods, ordinary and delay differential equation models, network models, queuing networks and operational research approaches. | ||
Optical Tomographic Technology for Noninvasive Imaging of Human Hand and Foot Recent advances in miniature devices, as well as mobile communication, and ubiquitous computing, have fostered interest in wearable technology. Radio telemetry of human and animal vital functions, first introduced in the 1950’s, has today evolved into microelectronics for remote sensing of patients’ motion and location, heart (ECG) and brain (EEG) electrical activity, arterial pulse, blood pressure, and oxygen saturation, intestinal motility and acidity, internal tissue chemistry and gas pressures, as well as orthopedic and dental measurements.
Wearable systems (sometimes incorporated into garments, shoes, costume jewellery, or "bandaids") facilitate noninvasive and unobtrusive monitoring of individuals over extended periods of time. Such systems generally rely on wireless, miniature transmitters with adequate memory capacity to temporarily store data from sensors, than upload/transmit that data to a database server via a secure high reliability receiver link (radio, optical, induction) often through a LAN or Internet connection.
New techniques for short range radio communication unencumbered by regulatory restrictions (viz, wideband spread spectrum) enable wireless monitoring of ambulatory subjects both in home care and hospital that is relatively immune to interference. The following specific aims are addressed in this research:
1. Development and study of new generation, generically applicable biosensors. Reliable biosensor design, test, and packaging, emphasizing motion tolerance, stability control of a sensed monitoring signal, modular system architecture for easy modification/expandability, and user-friendly packaging.
2. Research methods for the integration of low-power digital radio. Wearable digital radio communication integrated with wearable monitors based on these biosensors. Ultra low-power and fault tolerant solutions will be proposed.
3. Investigate new algorithms optimized for rapid yet robust biosignal processing. The overarching goal of this project is to create solutions that will optimize lifetime wellness of a person, thereby enhancing quality of life, permit independent living as long as possible, provide real-time support and advice as an electronic "health companion", and (eventually) reduce the overall life cycle cost of health and medical care.
This interdisciplinary project involves bioengineering at the interface between human physiology, sensors, telemedicine, wireless communication, biocompatible materials and packaging, microsystem design focused on low-power and fault-tolerance, combined with computer science research in ubiquitous computing, clinical research and psychosocial study. | ||
Petr Lisonek & Jonathan Jedwab Computational Study of Discrete Mathematics Problems Arising in Digital Communication This project is an exploratory computational study of various discrete mathematics problems arising in digital communication. Solutions to problems such as these have for many years played a powerful enabling role in areas of application such as data storage and transmission, position determination, synchronization, data compression, optical time domain reflectometry, and signal transmission from deep space. The project lies on the boundary between discrete mathematics, computing science, and communications engineering.
Current Projects:
1. The structure of q-ary linear codes of minimum distance 4 and 5.
These are the smallest cases for which the problem of finding optimal codes remains unsolved (except when q=2 and d=4). These codes admit a simple geometric characterization in terms of point sets in finite projective spaces and their study provides an interesting link between algebra, combinatorics and geometry. One possible approach to finding good codes is to refine the minimum distance condition to a more detailed measure, such as studying the size and structure of the set of words of minimum weight. These codes are applied in digital communication (detecting and correcting errors ccurring during data storage/transmission) and in the design of statistical experiments.
2. The determination of the asymptotic maximum merit factor of binary sequences.
This is one of the fundamental problems of digital communication, studied since the 1950s. In equivalent guise it is an old unsolved problem in complex analysis. Extensive computational exploration has recently shed new light on this problem.
3. The structure of Golay complementary sequences.
These sequences have a long history of application to digital communication, most recently as a means of controlling power in wireless multicarrier transmission. The recent discovery of a connection between these sequences and Reed-Muller codes produces practical coding schemes for wireless transmission having powerful algebraic error-correction and tight power control. | ||
Bio-inspired Robotics This project concerns the design of robotic systems inspired by natural principles. It is intrinsically interdisciplinary interdisciplinary as it involves (1) the study of biological systems and the analysis of their physiological, chemical, biomechanical and neurological properties, and (2) the desgn of robotic systems including the development their mechanical, electrical, electronic and control subsystems. The final objective is the development of high performing robotic prototypes based on the physical principles found in natural organisms.
Description:
The success of biological organisms in solving problems encountered in their environments is attributed to the process of natural selection, the rigors of this process ensuring the efficacy of the results. Biological systems represent the fruits of optimization through trial-and-error that has been in progress over billions of years, and the 1.7 million species that have been catalogued so far can be seen as a vast resource for inspiration of scientists and engineers. Biomimetics tries to extract concepts from biological systems that will allow the design of better, novel solutions, not merely imitating organisms' characteristics but distilling aspects that can be applied effectively from complex integrated systems. Problems that biological systems face are often similar to those faced by engineers. Given the effectiveness with which some of these have been overcome, biologically inspired concepts should be considered seriously when designing new solutions. Although humans have been being inspired by nature for a long time, this process has been on an ad hoc basis. With the continuing emergency of biomimetics as a distinct scientific discipline, the systematic search for biomimetic solutions to particular problems is an increasingly important focus. Adaptability, autonomy, miniaturization, holistic design, reliability, robustness, self-repair, self-replication are the main traits that can be found in many biological organisms that are of particular interest in space systems design, with its particular requirements and constraints. In this project the basis for a biomimetic design process that is generally applicable, comprehensive and systematic in the search for solutions is investigated.
The biomimetic process, which is developed in the framework of this project, is applied in the design of different robotic systems of scientific and industrial interests. For instance, a strong interdisciplinary research program dedicated to providing scientific and engineering leadership in the development of robust and energy efficient bio-inspired climbing robotic systems will be developed. Applications may be categorized under four key areas: 1) Servicing (e.g., maintenance of skyscrapers, ships' hulls, nuclear plants, etc.); 2) Rescue (e.g., during fire, earthquakes, landslide, etc.); 3) security (e.g., surveillance, inspection and military operations in premises and natural harsh environments, etc.); 4) Space (e.g., planetary exploration, Intra-Vehicular Activities, Extra-Vehicular Activities, etc.). Evolutionary examples will be used to design and develop engineered systems based on the principles of climbing in nature. So far the research performed in this field has demonstrated the value of the biomimetic approach, but current bio-inspired climbing prototypes lack both robustness and agaility. The research will focus on the synthesis of a robust and energy efficient climbing mechanism, which relies on the use of biomimetic attaching systems (e.g., gecko adhesive) previously investigated by the author. The current goal is to design a mechanism that enables the development of robotic systems capable of moving on both horizontal and inclined surfaces, as well as transferring between surfaces with differing gradients. During the scope of this project, the interaction between the mechanism and the adhering surface will be investigated. In order to maximize contact surface area, the research will focus on the design of an underactuated system capable of complying with both surface roughness and geometry. The kinematics, stiffness and dynamics of the synthesized mechanism will be investigated in order to optimize its design. Reliability is the paramount concern for climbing systems, as falls generally cause unacceptable damage. Therefore, the robotic system will be designed to prevent adhesion failure. Miniaturized tactile and acceleration sensors will be considered for monitoring and controlling the interaction of the mechanism with the surface. | ||
Computational Graph Theory Graph Theory is a topic in mathematics which is of central importance to Combinatorics and Theoretical Computer Science. The interaction between graph theory and computation has been developing steadily in the past 25 years. This interaction goes two ways: graphs are applied to computation, and computation is applied to graph theory. This project involves both aspects. Algorithms will be developed for solving some graph theoretical problems which commonly arise in diverse disciplines. Conversely, we shall use computational resources to attack several outstanding problems in graph theory. | ||
Helping Entangle the Web of Life with Directed Graphs All life is related, and a family tree of species is its ultimate representation. Events on the tree can even be dated using molecular data, and so we can tell not only who is related to whom, but by how much. There are interesting problems associated with both building and using trees of species. For one, it seems many species are mosaics of genes derived from different ancestors, much like a child having several mothers. We will help analyse this pattern of evolution based on the theory of directed graphs, with input from collaborators in New Zealand and Germany. Another interesting problem is comparing the true tree of life with what we might expect it to look like under different models of evolution, both with respect to its shape (akin to variation in family sizes) and with respect to the timing of events (when families grow and shrink). This latter comparison assumes that the true tree is properly dated, which is an interesting technical problem in itself. Finally, every time we threaten a species with extinction we threaten a bit of the tree, which will be lopped off forever. The pattern of extinction in nature affects the pattern by which the tree shrinks, and we are interested in modeling this form of evolutionary topiary. | ||
IRMACS Working Group in Fluid Dynamics & Applied Analysis
Fluid dynamics, the study of the motion of liquids and gases, is one of the classical branches of applied mathematics. With the rise of modern computing, many of the most intense areas of fluid research now involve interdisciplinary efforts. Sciences, such as aerodynamics and meteorology, draw heavily on the mathematics of fluid mechanics for their quantitative underpinnings and for the advancement of large-scale computational models. Many projects currently investigated at SFU lie at the confluence of numerical computing, nonlinear dynamics and analysis of partial differential equations.
This IRMACS working group serves as the focal point for several independent research efforts at SFU with common theme of the mathematics of fluids and continuum materials. The participants, comprising both research efforts at SFU with common theme of the mathematics of fluids and continuum materials. The participants, comprising both established researchers and students, will be enriched by the proximity to the broader SFU research community who all profit from the rising technologies of visualization, high-performance computing and computer graphics.
Current Projects
1. Flow dynamics of the midlatitude atmosphere. Active projects involve collaborations with computational scientists at Texas A&M, and meteorologists at NCAR Boulder and the University of Washington.
2. Heat transport in turbulent convection. Active projects involve collaborations with applied mathematicians at the University of Michigan.
3. Variational analysis of microphase separation of diblock copolymers. Active projects involve collaborations with mathematicians at New York University and the Universitat Bonn. | ||
Mathematical models and simulation strategies: from nanodevices to bone grafts | ||
Bipolar Affective Disorder and Older Adults (BADAS) Study It is estimated that there are today 75,000 Canadians 50+ years of age with bipolar disorder (BD); moreover, the number of older Canadians with BD will triple over the next 10 years. Despite these growing numbers, psychosocial research focussing on older adults with BD is virtually nonexistent. This proposed 5-year study will include intensive periods of data collection; these
2-week periods will each separated by 8-months. Participants will be prompted at 2-times per day (12 hour window) to report current mood, medication adherence and recent life events. We envision use of a GPS located electronically connected to an iPad or similar tablet-type device. The GPS information (recorded every 20 seconds) will allow us to determine if periods of mania are heralded by expanding geographic range, rapid movement between points or, novelty seeking; conversely, contraction of movements may be a precursor to major depression episodes. Two-hundred and five participants will be recruited from both urban and rural communities with a 10+ year BD diagnosis; medical information will be obtained during regular psychiatric assessments. We will use a range of contemporary research methods with emphasis on BD in later life (e.g., retirement, bereavement, concurrent physical illness). This study will provide a wealth of information to increase our understanding of BD in older adults where little information currently exists. | ||
Development of High Sensitivity Fluorescent Detection System We are going to develop a novel flourescence detection system based on con-focal scanning device with high sensitivity to microarray readout. The probe molecules are placed with special pattern, so that the flourescence emission image pattern has this specific geometry. The Image processing method such as matched filtering will be applied to aprove the SNR of flourescence signal. Numerical analysis of optical flied is also performed to optimize the optical design of the system. | ||
Actuarial Models The aim of this project is to develop and study actuarial models. Actuaries have to assess the insurance and financial risks of long-term insurance contracts offered by insurers. Understanding those risks is important for pricing, risk management, capital requirements and solvency. Sophisticated mathematical, statistical and computational methods are needed to study these models. | ||
Tele-Manipulation Over the Internet The ability to manipulate and interact with the remote environment has attracted system engineering in the robotics field for many years. The introduction of the internet as a means of communication has even extended the potential application of robotic tele-manipulation systems. Currently it is possible to interact with any remote area by means of Internet communication line. For example, a series of mobile robots can be deployed to explore hostile territories and be able to manipulate their environment through user control devices having Internet connection. | ||
Randall Peterman & Sean Cox & Andrew Cooper Modelling Interdisciplinary Problems in Fisheries Management Fisheries science seeks robust solutions to complex ecological, economic, and social problems. Integrating these areas requires quantitative research methods that draw on computer science, mathematics, statistics, engineering, and systems theory. The Quantitative Modeling in Fisheries Research Group (QMFRG) involves interdisciplinary projects that promote training of highly qualified personnel in these areas, and facilitates interactions between researchers, fisheries managers, and resource users, including First Nations and the fishing industry. | ||
Vancouver Institute for Visual Analytics VIVA will grow and support visual analytics research currently being conducted in Canada, primarily in the Vancouver area at the University of British Columbia (UBC) and Simon Fraser University (SFU). The context for this VA research involves the study of real world problems encountered by industry and governmental organizations.
VIVA will develop a visual analytics research network infrastructure that will establish Vancouver as the locus of visual analytics research, expertise and educational programming for all of Canada.
VIVA is building a capacity to train visual analytics human resources from all areas, e.g., university students and company employees, and at all levels, e.g., novice and experienced trainees, in a learning environment that includes access to real data, to a wide range of VA tools, and to the best practices and researchers in the field.
How VIVA can help Academic Researchers
Help prepare VA research proposals and bring together potential research teams, including researchers, students, subject matter experts and tool experts.
Provide access to real world problems, datasets and VA tools and laboratories.
Supply the means to evaluate and distribute tools and methods that have been developed by VA researchers.
Help find and make available support for students working on VA projects.
See what VIVA can do for Researchers.
How VIVA can help Companies and Organizations
Bring together researchers, including students, interns, subject matter experts, and VA tool experts to solve analytical problems associated with a company’s or organization’s large datasets.
Offer a series of VA technical courses and workshops for training and upgrading the VA capabilities of personnel.
Provide access to VA tools and laboratories and conduct VA tool evaluation sessions.
Provide access to analysts, VA tool specialists, and graduating students trained in VA methods and tool use. | ||
Hydrodynamic Modeling for Fjords and Lakes in Rivers and Smith Inlet Watersheds The project will involve the building of hydrodynamic models of fjord systems on the British Columbia Central Cost. These are important habitat for once-valuable sockeye salmon (Oncorhynchus nerka) populations. The primary model will be for Rivers Inlet, a 30 X 30 km inlet with a large glacier-fed river at its head and a sill constricting deep ocean water entry near its mouth. This research also requires collecting field observations and depends on a mix of interdisciplinary expertise in mathematical modeling, statistical analyses, and physical and biological oceanography/limnology. | ||
Complex Systems Modelling Group The IRMACS Complex Systems Modelling Group (CSMG) models complex systems central to social welfare issues, with particular emphasis on modelling in healthcare and criminology. The group approaches modelling with the guiding principle that a good model is one that is both mathematically sound and applicable to real situations. The CSMG is unique in the academic diversity of its members and the breadth of its interests. Critical to the group's success is its partnership with the IRMACS Centre, which hosts and facilitates the CSMG's research through its state-of-the-art collaborative and computational resources as well as its professional management support team. The CSMG's models unite sophisticated mathematical theory with real-world applications. The group's models have played a role in crafting public policy through its collaborations with British Columbia's Ministries and other policymakers, including the Ministry of Health Services, the Ministry of Public Safety and Solicitor General, the Ministry of Attorney General and the British Columbia Centre for Excellence in HIV/AIDS. A current focus of the CSMG is modeling the complex relationships between the police, the Crown Attorney's office, the court and the corrections systems of British Columbia's criminal justice system. The CSMG is also currently modelling the expansion of highly active antiretroviral treatment (HAART) in combating the HIV epidemic in Vancouver's Downtown Eastside. The CSMG's strength is its ability to join the theoretical with the practical in unique and innovative ways. | ||
Bioinformatics Algorithims for Infectious Diseases
Infectious diseases are a leading cause of productivity loss and are responsible for roughly a third of annual deaths worldwide; sepsis and mortality caused by infectious diseases are also on the rise in the developed world. Antimicrobial resistance is increasing rapidly and newly emerging diseases are causing considerable concern: a new global pandemic could have a significant economic impact.
With the advent of microbial whole-genome sequencing, there has been some renewed optimism that genomic knowledge will speed the development of new antimicrobials, vaccines and diagnostics. Some success stories have been reported to date, however these have been extensive/costly endeavors involving significant laboratory requirements. This is largely due to the fact that the existing computational screens for identifying potential drug targets and vaccine components are not accurate enough.
Our recently funded CTEF project on combating infectious diseases aims to improve the effectiveness of genomic approaches for anti infective drug discovery through a technology driven, interdisciplinary methodology. The project aims to develop more accurate and faster bioinformatics algorithms and tools for identifying anti-infective drug targets, candidate drugs and potential vaccines. Our interdisciplinary team, composed of PIs Cenk Sahinalp and Fiona Brinkman and 8 other investigators, will capitalize on SFU|’s unique strengths in computational, physical, chemical and biological sciences to discover potential new therapeutic targets and test them first in silico and then in the laboratory. Our program will provide an environment for trainees from the basic and applied sciences to learn career skills relevant to performing interesting interdisciplinary, team-based, internationally competitive research. With the ability to analyze many infectious disease-causing microbes in parallel, the computational methods we will develop could potentially have a wide impact on efforts to control multiple infectious diseases.
This application for IRMACS membership is for supporting the tightly interdisciplinary nature of the project, requesting facilities for research meetings. The specific needs we have include larger meeting rooms that can accommodate all investigators (~10 per year) and smaller rooms for sub-project meetings involving at most 5 investigators (~25 per year). We also may need to use the presentation facility for talks by invited speakers. | ||
Estimating Herring Migration Estimation of herring movement patterns from capture, recapture, etc. MITACS Internship with Pacific Biological Station, Dept. of Fisheries & Oceans, Nanaimo. | ||
Bridging Genomics, Social Sciences, and Humanities to Reduce HIV Transmission in Saskatchewan The Bridging Genomics, Social Sciences, and Humanities to Reduce HIV Transmission in Saskatchewan, is uniquely poised to translate expertise in modelling complex social networks and pathogen transmission dynamics to the HIV epidemic in Saskatchewan (SK). This epidemic is driven by one of the highest rates of infection in the western world (~19 new HIV infections per 100,000 population per year) , and it is estimated that this epidemic directly costs $40M/year and another $100M in indirect costs. Unique to SK, HIV spread is mainly via injection-drug users (IDUs), with a disproportionate burden among First Nations and Metis peoples and young women (18-29 years). Also unique is the relatively low genetic complexity of circulating HIVs. Also of concern is the unusually rapid progression to AIDS; reasons for this are likely multifactorial including social determinants of health (e.g., poverty, addiction and homelessness, and lack of access to health care system), and biological factors (e.g., viral fitness and immune response to HIV and HIV/HCV co-infection).
This project will follow an interdisciplinary strategy for addressing the biological and social factors behind transmission of HIV and progression to AIDS. This project will use in-depth genomic sequencing of HIV and HCV circulating in SK (most HIV+ cases in SK involve co-infection with hepatitis C virus, HCV), in order to test the hypothesis that the phylogeography of HCV, particularly of early infections, will inform where new HIV infections will arise. | ||
Sustaining Quality of Life for the Rapidly Increasing Aging Population By 2031, more than nine million Canadians (25%) will be aged over 65, and as many as 45% of them will report some form of disability through physical or cognitive impairment, chronic disease or frailty . There is therefore a crucial need for innovative and economically sustainable approaches to meet the future social and health care needs of older people and provide services that promote independent living and positively enhance their quality of life. This project's interdisciplinary research team is uniquely qualified to address these challenges and integrates social and health sciences, engineering, computing science and applied maths, communications, policy studies, economics and business. | ||
Boolean Function Generation for Complex Systems Summary:
We study algorithms for generating the minimal operating and failure modes of a complex system controlled by many boolean (true-false) variables. This is a fundamental algorithmic question that has unexpected theoretical properties and is poorly understood computationally. However, these "boolean functions" arise naturally in models of complex systems, notably in computational biology.
Description:
Complex systems are often controlled by many boolean (binary) variables, whose values are either "true" or "false". We would like to characterize how these variables affect a particular behaviour of the system, which itself is boolean. Suppose the behaviour is monotone in the sense that, given a setting of the variables that permits the behaviour, if additional variables are set to "true" the behaviour is still permitted. Then this behaviour is a monotone boolean function of the variables. Such a function is characterized uniquely by both the minimal sets of variables permitting the behaviour and the minimal sets of variables inhibiting the behaviour.
This situation is common in complex systems, such as those that comprise computational biology. As an example, a metabolic network can be characterized in its metabolites and reactions. In a steady state many of these reactions operate simultaneously. When some of these reactions are knocked out, various behaviours of the system will be blocked. We then have a boolean function which can be described either through elementary modes, i.e. minimal sets of reactions supporting the behaviour, or minimal cut sets blocking the behaviour.
Our goal is to develop efficient algorithms to enumerate these minimal sets, and to understand them both theoretically and computationally. We proceed from an oracle that evaluates the function. In the metabolic networks example mentioned above, this can be implemented as a simple linear program based on the stoichiometric matrix that records the number of metabolites produced and consumed by each reaction.
We are motivated in part by the novel algorithm of Fredman and Khachiyan which generates these forms with a surprisingly good worst-case complexity, but is not well understood in practice. These ideas also have an interesting connection to fundamental questions in computational geometry on describing polyhedra. | ||
Modelling and Simulation of Fluid Flows with Industrial Applications This project centres around the application of mathematical and computational methods to the study of complex fluid flows, motivated largely by industrial applications. The complexity arises from the presence of nonlinear coupling between a flow and some other physical process, such as when a fluid interacts with a deformable elastic interface, or when capillary forces drive the flow through a porous medium, or when social or behavioural forces influence an individual's motion in a pedestrian flow. These "multi-physics" phenomena lead to very challenging mathematical problems and also typically require specialized algorithms for their numerical solution. | ||
Studies in Sampling and Experimental Design
This project supports collaborative and individual research in sampling and related experimental design issues. Current problems in the social, health and biological sciences create the need for new design methodologies in spatial, temporal, and network settings. The research effort of this project includes adaptive and link-tracing designs, designs which the sampling units are in motion, and designs for experiments interventions in real populations. | ||
High Performance Networks: Modeling, Simulation & Analysis The proposed research program deals with simulation and analysis of traffic, protocols, and control algorithms in high-performance packet networks.
The research problems are interdisciplinary and require expertise in packet data networks (engineering and technology), statistical tools and analysis (applied mathematics), and data mining and visualization of large data sets (computing science).
Current Projects
1. Analysis of traffic traces and billing records from deployed wireless networks (E-Comm and Telus Mobility);
2. Use of analytical tools for traffic characterization and estimation of network performance;
3. Analysis and simulation of network protocols with active queue management schemes;
4. Application of control theory to modeling and analysis of network dynamics. | ||
Stochastic Modelling and Simulation in the Natural and Cognitive Sciences My research concerns the modeling of various phenomena in the natural sciences and in linguistics and psychology, as well as the subsequent analysis and simulation of those models. I focus on problems where I can use my knowledge and experience with dynamical systems and stochastic processes, especially stochastic differential equations.
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Investigation of 11-dimensional Supergravity in Light Cone Gauge The project involves theoretical studies of the properties of 11-d supergravity in the light-cone (L.C.) guage. 1-d supergravity is the low energy limit of the so called M-theory which is conjectured to be the generalization of the Superstring theory. Superstring theories are the only known quantum theory of all fundamental interactions including gravity that seems to be viable. In our project we plan to study formulating 11-d supergravity in L.C. gauge using superfield formalism. We want to study 4-gravitation scattering amplitudes which arise from terms container 4 Riemann tensors (R4 terms) in the action. These terms are not contained in the standard Einstein action. Since we plan to use superfield formulation, these calculations will yield other amplitudes i.e., those that involve supersymmetric partners of the graviton, the spin 3/2 fermion and the three index antisymmetric spin 1 field. In collaboration with my longtime coworkers, Professors R. Parthasarathy and Radoslav Rashkov, I have started writing a monograph for researchers on 11-d supergravity. I hope to be able to finish this project in the next year. | ||
Transcendental numbers and recursive structures in Feynman Diagrams This project seeks to further the understanding of quantum field theory with a graphs first approach and a focus on combinatorial tools. In particular, the project seeks to better understand the recursive structure of Feynman diagrams and how this impacts the growth of Green functions, and to better understand the transcendental content of individual Feynman integrals by looking at spanning forest polynomials of the graph and related constructions. This project is international and combines expertise and researchers in mathematics and physics. IRMACS can provide a local home for the project; housing visitors and students, and providing a centre for collaboration and discussion.
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Modelling Climate-Carbon Cycle Interactions With the development of coupled climate-carbon cycle or "Earth System" models new insights are emerging about the response of the climate system to anthropogenic carbon emissions. Particularly, it has been shown that feedbacks between climate and the carbon cycle have the potential to significantly amplify the climate changes resulting from anthropogenic carbon dioxide (CO2) emissions, and that these feedbacks render CO2-induced climate change largely irreversible on timescales of centuries to millennia. The goal of this project is to use and further develop the University of Victoria Earth system climate model to better constrain future climate-carbon cycle feedbacks, to explore the reversibility of anthropogenic climate change, and to investigate the role of climate-carbon cycle feedbacks for the attainability of climate stabilization targets.
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Artificial Models of Biomolecular Motors This Project is the basis of a close collaboration with the experimental group of Professor Heiner Linke of the Department of Physics University of Oregon. We plan an integrated approach of experiment and theory to construct artificial molecular motors in order to understand the generic features common to biological molecular motors and, eventually, to examine the possibility of industrial applications. |
