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``Real-World'' Problems in Search of Solutions / Problèmes
mathématiques
provenant du monde industriel
(Org: André Dabrowski)
- LIANG CHEN, Department of Physics, University of Ottawa, Ottawa,
Ontario K1N 6N5
Polarization mode dispersion and polarization dependent
loss in single mode fiber communication systems
[PDF] -
Single mode fibers in fiber optic communication networks in fact
supports two degenerate polarization modes. This degeneracy, however,
could be lifted by either environmental perturbations or by
manufacturing imperfections during fabrication. As a result, light
group velocity can become polarization dependent, this is the so-called
polarization mode dispersion (PMD). Furthermore the light intensity
attenuation can also become polarization dependent, this is the
so-called polarization dependent loss (PDL). PMD will broaden an
optical pulsewidth, while PDL will result in optical power
fluctuation. PMD and PDL will thus induce extra bit-error for a high
rate digital optic communications fiber network. Because fibers
installed in the field are subjected to dynamic environments such as
wind and temperature, the PMD and PDL interactions are therefore
intrinsically statistical. We will review the challenges of calculating
precisely what the impact of combined PMD and PDL on high speed
communication systems.
- GENERAL DISCUSSION
[PDF] -
- GENERAL DISCUSSION
[PDF] -
- ERIC DUBOIS, Faculty of Engineering, University of Ottawa, Ottawa,
Ontario K1N 6N5
Representation of 3D environments based on images
[PDF] -
Virtual reality systems are generally based on computer graphics models
of scenes and objects. With a complete model, it is possible to
navigate in a virtual environment by generating the images as needed on
a virtual camera. This is widely used in video games. However, if we
want to remotely navigate in a real, existing physical environment, it
is very costly and time-consuming, if not impossible, to generate an
accurate graphics model of the entire environment. It is more realistic
to accomplish this based on actual images taken of the environment.
This field, called image-based rendering, is quite new and there
remain many unsolved questions: Which images should be captured-how
many and from what viewpoints? How should this potentially enormous
dataset be represented and stored? How can arbitrary views be rendered
quickly for real-time navigation, with high quality? How can the system
be designed for remote navigation, say over the internet? These issues
will be surveyed in this talk.
- MARY HEFFORD, Centre for Biologics Research, Biologics and Genetic Therapies
Directorate, Health Canada, Ottawa, Ontario K1A 0L2
Calculating protein-protein interactions in proteomes in both
health and disease
[PDF] -
Many, if not most, diseases alter the number, the kind or the
properties of the proteins expressed in cells-the cellular proteome.
Using a combination of database searching, predictive algorithms and
the traditional tools of protein chemistry, scientists are beginning to
systematically unravel the human proteome into discrete, functional
components of interacting proteins. Through the identification of
protein-protein interactions that are altered in diseased states we
gain new insights into the mechanisms of pathology and new hopes for
effective treatments.
- ANDRÉ LONGTIN, Department of Physics, University of Ottawa,
Ottawa, Ontario K1N 6N5
Stochastic dynamics of biological information
[PDF] -
This talk focusses on new mathematical challenges that arise in the
context of biological problems. The first concerns the motion of eyes
during reading. We have recently proposed a model for such eye
movements which assumes that information is gathered from words in
parallel in the word stream. The model has an intrinsic memory that
expands with time. This expanding memory of the incoming words, as
well as the ``forcing'' of the ``reading system'' by sequences of words
of differing difficulties and with serial correlations pose great
mathematical challenges. Another context in which information is
gathered from an environment occus in swarm intelligence problems. For
example, ant colonies communicate with each other directly as well as
through environment signals (such as the magnitude of food resources).
In many colonies, there is non-hierarchical control in which ants
perform different different tasks, and switch tasks as well. We will
discuss the deterministic/stochastic dynamics of such task allocation
in terms of birth-death processes, and discuss the challenges involved
in incorporating the spatial domain in such problems.
- REJEAN MUNGER, University of Ottawa Eye Institute, Ottawa Health Research Institute,
Ottawa Hospital, Ottawa, Ontario
Modeling the optics of the human eye: An interesting mathematical
enigma
[PDF] -
Our visual perception of the world is the result of many factors, some
physiological, some neural and some optical. The first step in this
process is the formation of an image of the world in the back of the
eye, the retina, where the photoreceptors, the light detectors, are
located. As an optical instrument the eye is relatively simple in
construction having only 2 refractive elements and one limiting
aperture. Yet we have yet to build a model of the optics of a normal
human eye that can be useful in clinical applications. We will discuss
the mathematical issues that arise when (A) collecting data for
deriving the model and (B) in solving for the optical system.
- MICHAEL RUDNICKI, Department of Cellular and Molecular Medicine, University
of Ottawa, Ottawa, Ontario K1N 6N5
The stem cell genomics project
[PDF] -
The molecular mechanisms that regulate the formation, self-renewal, and
differentiation of stem cells remain at best poorly understood. The
full exploitation of the potential of stem cells will require a
complete understanding of the genetic factors that specify stem cell
identity, and that regulate the commitment towards specific
differentiated cell lineages. Therefore, we propose to define the
spectrum of genes that define the identity and regulate the plasticity
of embryonic and adult stem cells. This is the overarching goal of the
Stem Cell Genomics Project. We will work primarily with human and
mouse embryonic, neural, muscle, and marrow stem cells, and utilize
high-throughput genomic analyses towards achieving this objective. A
variety of stem cells will be isolated using a range of methodologies
from both embryos and from a variety of adult tissues. We will employ
emerging technologies to conduct expression microarray analysis on as
few as 1-10 cells. Cluster analysis of multiple stem cell isolates and
their immediate downstream differentiated derivatives will identify
genes that are enriched or specifically expressed within the stem cell
compartment. This data will then be used as a baseline to investigate
the changes in gene expression that occur early during stem cell
commitment and differentiation. To facilitate gene discovery and to
complement the microarray analysis, we will employ serial analysis of
gene expression (SAGE). A proteomics approach will be employed to
monitor protein expression profiles from both immature stem cells and
differentiated cells. Full exploitation of the stem cell expression
data will be facilitated by the mounting of a web site for the
dissemination and analysis of data (StemBase). This approach will
facilitate large-scale reiterative analysis to elucidate hierarchical
molecular regulatory mechanisms during stem cell commitment as well as
stratification of subtle differences in stem cell states or
identities.
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