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Event(s) on November 2008
- 4/11/2008
| 題目: |
A Tailored finite point method for a singular perturbation problem on an unbounded domain |
| 講員: |
Prof. HAN Houde, Department of Mathematics, Tsinghua University, China |
| 時間/地點: |
11:30 - 12:30
FSC1217, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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| 摘要: |
In this talk, we propose a tailored-finite-point method for a
kind of singular perturbation problems in unbounded domains.
First, we use the artificial boundary method to reduce the original
problem to a problem on bounded computational domain. Then we
propose a new approach to construct a discrete scheme for the
reduced problem, where our finite point method has been tailored
to some particular properties of solutions of the original problem.
From the numerical results, we find that our new methods can
achieve very high accuracy with very coarse mesh even for very
small parameter $e$. In the contrast, the traditional finite
element method
does not get satisfactory numerical results with the same mesh.
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- 5/11/2008
| 題目: |
Laplacian eigenvalues of graphs |
| 講員: |
Mr. Li Jianxi, Department of Mathematics, Hong Kong Baptist University, HKSAR, China |
| 時間/地點: |
10:30 - 11:30
FSC1217 Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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| 摘要: |
Let G = (V; E) be a simple connected graph. The matrix L(G) =
D(G) - A(G) is called the Laplacian matrix of G, where D(G) is
the diagonal matrix of vertex degrees and A(G) is the adjacency
matrix of G, respectively. The eigenvalues of L(G) are called
the Laplacian eigenvalues of G, which have numerous applications
in various fields. In this talk, we will describe the background
and state some problems as well as previous results on the Laplacian
spectral radius of graphs. Among these problems, we firstly improve
Shi's upper bounds for the Laplacian spectral radius of irregular
graphs, and obtain some new upper bounds for the Laplacian spectral
radius of graphs (in particular, for bipartite graphs, to some
extent, we have obtained better upper bounds). Secondly, we determine
graphs with maximum Laplacian spectral radius in some classes
of graphs. Lastly, we order some trees according to their Lapla-cian
spectral radii. Finally, we provide some directions in further
investigations of Laplacian eigenvalues of graphs.
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- 7/11/2008
| 題目: |
Planning for Disaster - Designing Robust Coverage Networks to Hedge against Worst-Case Facility Losses |
| 講員: |
Dr. Jesse Rush O`Hanley, Kent Business School, University of Kent, UK |
| 時間/地點: |
10:45 - 11:45
FSC1111, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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| 摘要: |
The potential for long-term facility loss has important implications
for the reliability of service/supply networks. In order to design
a coverage-type service network that is robust to the worst instances
of facility loss, we develop a location-interdiction covering
model that maximizes a combination of 1) initial coverage given
p facilities and 2) the minimum coverage level following the
loss of any subset of facilities r < p. The problem is formulated
both as a mixed integer program and as a bilevel mixed integer
program. To solve the bilevel program optimally, a decomposition
algorithm is presented, whereby the original bilevel program
is decoupled into an upper level master problem and a lower level
subproblem. After sequentially solving these problems, information
is fed back to the upper level master by appending supervalid
inequalities, which attempt to force the upper level master away
from clearly dominated solutions. Supervalid inequalities, unlike
standard valid inequalities used in cutting plane algorithms,
cut away parts of the feasible region but are guaranteed not
to remove all optimal solutions unless an optimal solution has
already been found. Computational results show that when solved
to optimality, bilevel decomposition is up to several orders
of magnitude faster than performing branch and bound on the mixed
integer program.
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- 10/11/2008
| 題目: |
A Hybrid Approach For Solving Sparse Linear Least Squares Problems |
| 講員: |
Dr. Esmond G. Ng , Lawrence Berkeley National Laboratory, USA |
| 時間/地點: |
11:30 - 12:30
FSC1217, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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| 摘要: |
We propose a hybrid method for solving large sparse linear least
squares problems. The method is iterative in nature, as it is
based on preconditioned LSQR. However, the preconditioner comes
from an orthogonal factorization of a submatrix of the original
matrix associated with the least squares problem; the construction
of the preconditioner is based on well-known techniques in sparse
direct methods. In this talk, we will discuss the quality of
the preconditioner and the choices of the submatrix.
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- 11/11/2008
| 題目: |
Quantum Transition State Theory |
| 講員: |
Dr. Shi Jing, Assistant Professor of Mathematics, Wayne State University, USA |
| 時間/地點: |
11:30 - 12:30
FSC1217, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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| 摘要: |
Quantum tunneling plays crucial roles in some physical and chemical
processes, ranging from quantum cosmology to enzymatic reactions.
The quantum nature of the motion often comes along with multidimensionality,
namely the coupled motion of many degrees of freedom. The high
dimensionality of the potential energy surface poses a great
challenge in both theoretical and numerical descriptions of tunneling.
Numerical simulation based on the Schrodinger equation is often
prohibitively expensive. In this talk we discuss an efficient
and accurate numerical method to calculate the tunneling transition,
based on the quantum t ransition state theory in Feynman path
space. It is free from any further ad hoc assumptions ('adiabatic'
or 'sudden') and does not require pre-defined reaction coordinates.
The application to hydrogen tunneling transfer in polyatomic
molecules will also be demonstrated.
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- 12/11/2008
| 題目: |
Symbolic Computations in Mathematics by Maple |
| 講員: |
Prof. Wen-Xiu Ma, Department of Mathematics and Statistics, University of South Florida, USA |
| 時間/地點: |
14:00 - 15:00
FSC1217, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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| 摘要: |
This is an introductory talk about a course on symbolic computations
in mathematics by Maple. The course aims to teach students
to use symbolic programming systems to solve mathematics problems.
Upon completing the course, s tudents will be able to employ
computer algebra systems to perform various symbolic computations
in mathematics, particularly in linear algebra, number theory
and calculus. I will focus on what audience the course is targeted
at and what it is about, etc.
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- 12/11/2008
| 題目: |
ICM Distinguished Computational Mathematics Lecture: Sublinear Algebra for Multidimensional Tensor Problems |
| 講員: |
Prof. Eugene Tyrtyshnikov , Institute of Numerical Mathematics, Russian Academy of Sciences, Russia |
| 時間/地點: |
15:30 - 16:30
RRS905, Sir Run Run Shaw Building, Ho Sin Hang Campus, Hong Kong Baptist University
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| 摘要: |
By a tensor problem in general, we mean one where all data on
input and output are given exactly or approximately in tensor
formats defined by a small number of parameters compared to the
total amount of data. For such problems we propose to seek for
algorithms that work with data exclusively in tensor formats,
the price we pay is a contamination of data through some approximation
(recompression) at each operation.
We show that a certain intentional corruption of data, under
pretty mild assumptions, still preserves the convergence rate
of superlinear iterations. Then, we discuss which tensor formats
are best suitable and advocate to deal with the Tucker format
for all operands.
As an application, we present new approximate matrix inversion
algorithms with linear and even sublinear complexity in the matrix
size and recent suggestions for construction of eigenvalue solvers.
Also, we discuss the gains of combination of tensor and typical
Toeplitzlike structures. In particular, doubly Toeplitz (block
Toeplitz with Toeplitz blocks) matrices of a wide class can be
approximately inverted with the complexity of order of square
root of the matrix size.
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- 17/11/2008
| 題目: |
NAG Seminar: Introduction to the Numerical Algorithms Group (NAG) |
| 講員: |
Prof. John Holden and Dr. Yuhe, Vice President Business Develpment, The Numerical Algorithms Group Limited, UK |
| 時間/地點: |
11:00 - 12:30
FSC1217, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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| 摘要: |
This seminar will be valuable for anyone wanting to write mathematical
and statistical code or applications and individuals wanting
to learn more about using NAG's numerical libraries. The NAG
Libraries contain more than 1,500 routines making them the largest
available collection of mathematical and statistical algorithms.
The libraries coverage is extensive including:
* Optimization,
* Ordinary and Partial Differential Equations
* Numerical integration and integral equations
* Linear Algebra
* Special functions
* Curve and surface fitting and interpolation
* Statistical functions
* And much more...
The presenters will also explain how NAG software can be used
within other software packages such as Maple, LabView, R, S-Plus
and C# / .NET, and demonstrate NAG's new Compiler for Windows,
Fortran Builder.
In the last part of the seminar we will give a few specific
examples for
financial mathematics / engineering.
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- 17/11/2008
| 題目: |
On Neural Network Conditional Autoregressive Value at Risk |
| 講員: |
Dr. Eric Fung, Department of Mathematics, Hong Kong Baptist University, Hong Kong |
| 時間/地點: |
14:30 - 15:30
FSC1217, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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- 18/11/2008
| 題目: |
Gamma Frailty Transformation Models for Multivariate Failure Times |
| 講員: |
Prof. Donglin Zeng, Department of Biostatistics School of Public Health, University of North Carolina, Chapel Hill, USA |
| 時間/地點: |
11:30 - 12:30
FSC1111, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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| 摘要: |
We propose a class of transformation models for multivariate failure
times. The class of transformation models generalize the usual
gamma-frailty model and yields a marginally linear transformation
model for each failure time. Nonparametric maximum likelihood
estimation is used for inference. The maximum likelihood estimators
for the regression coefficients are shown to be consistent and
asymptotically normal, and their asymptotic variances attain
the semiparametric efficiency bound. Simulation studies show
that the proposed estimation procedure provides asymptotically
efficient estimates and yields good inferential properties for
small sample sizes. The method is illustrated using real data
from a cardiovascular study.
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- 25/11/2008
| 題目: |
DLS: Some Solved and Unsolved Problems in High Accuracy Finite Elements |
| 講員: |
Prof. Lin Qun, Chinese Academy of Sciences, China |
| 時間/地點: |
11:00 - 12:30
ACC109, Jockey Club Academic Community Centre, Baptist University Road Campus, HKBU
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| 摘要: |
The simplest problem is the so-called “2p-conjecture”: people
guess a p-order finite element solution does has a 2p order accuracy
at nodes. This is true for ODEs and has been proved in 1970's
for Poisson equation for p<=3. There is no essential advance
before 2000. Recently, people work for p=4. Problem for p>4 is
still unsolved. There are more unsolved problems which will be
talked in this lecture.
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- 26/11/2008
| 題目: |
Graph Cut Algorithms |
| 講員: |
Dr. Andy C. Yau, Division of Mathematical Science, Nanyang Technological University, Singapore |
| 時間/地點: |
15:30 - 17:00
FSC 1217, Fong Shu Chuen Library, HSH Campus, Hong Kong Baptist University
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