Genetic instability is a major cause for abnormal cell
replication and carcinogenesis. But the mutant cells that replicate abnormally are also weaker and die at a more rapid rate. Hence, genetic instability is a two-edge sword in inducing cancer. The determination of the best time varying cell mutation rate for the fastest time to cancer can be formulated as a nonlinear optimal control problem. As generally the case for nonlinear optimal control problems, there is no general sure fire method for the solution of our problem. The talk will show how the unique solution of the problem can be obtained by ad hoc elementary analyses of the relevant boundary value problem for a systems of nonlinear differential equations. The
method of solution illustrates how important problems in application can be solved by elementary use of classical analysis.
We consider the the problem of approximating a given object x (say, a function) by a sequence (x_n), whose terms belong to the prescribed family of sets (A_n)$ (for instance, A_n may be
the space of polynomials of degree less than n). For each n, compute the distance E_n from x to A_n. How does the sequence (E_n) behave? What are the connections between its rate of
decrease and the properties of x? Can we discern any patterns in the sequence (E_n)? We attempt to answer these questions for different families (A_n).
Nonlinear Diffusions exhibit a variety of interesting and
sometimes unexpected behaviors. I shall
give a brief overview of this broad research area and emphasize some
applications.
Nonlinear Diffusions exhibit a variety of interesting and
sometimes unexpected behaviors. I shall
give a brief overview of this broad research area and emphasize some
applications.
In the numerical simulation of many practical problems in physics and
engineering, it is always an active research topic to efficiently and effectively
solve a set of partial differential equations (PDEs), which represents the
mathematical model of practical problems concerned. This talk is on the study of
advanced numerical methods for partial differential equations that arise from
scientific and engineering applications. The theme of research is on the
development, application and analysis of multilevel adaptive finite element methods.
I will discuss a basic result on the theory of chemical
reaction networks developed by Feinberg and others, which provides some
insight on the possible behaviors e.g. of protein networks inside a
cell. Then I will discuss an application of this theory to the study
of stochastic chemical reactions