View Year
See also the PSU Calendars
Log in to request a room reservation that will appear here for special events. Click on a day to view the room schedule for available times.
Weekly RSS Feed
A live feed of seminars and special events in the upcoming week.
- May 3rd, 2013 (03:35pm - 04:25pm)
- Seminar: Computational and Applied Mathematics Colloquium
Title: One-dimensional pressureless Euler/Euler-Poisson systems with or without viscosity
Speaker: Truyen Va Nguyen, Akron
Location: MB106We study the initial value problem for one-dimensional pressureless Euler/Euler-Poisson systems with or without viscosity. A general global existence result is established by employing the ``sticky particles'' model and letting the number of particles go to infinity. We first construct entropy solutions for some appropriate scalar conservation laws, then we show that these solutions encode all the information necessary to obtain solutions for the pressureless systems. Furthermore, an explicit rate of convergence of the sticky particle solutions to the solution for the continuous model is obtained via a contraction principle in the Wasserstein metric. Using this Wasserstein distance, we also study the vanishing viscosity limit for the systems. This is a joint work with Adrian Tudorascu.
- May 6th, 2013 (10:00am - 12:00pm)
- Seminar: Ph.D. Oral Comprehensive Examination
Title: "Poisson limit theorem for Gibbs-Markov systems"
Speaker: Xuan Zhang, Adviser: Manfred Denker, Penn State
Location: MB106Sinai studied Poisson limit distribution behaviour for eigenvalues in the quantum kicked-rotator model. Inspired by Sinai's work, Pitskel in- vestigated the Poisson limit distribution for return times of dynamical systems. He proved results for Markov chains with nite states and for hyperbolic toral automorphisms. Independently Hirata proved his result for subshifts of nite types with Gibbs measures and for Axiom A sys- tems. Many results have been proved for di enrent kinds of systems in recent years. In this talk, we will try to explain that Poisson limit dis- tribution also exists for Gibbs-Markov systems. Certain Markov chains with countable states will be special cases. We basically follow Hirata's method with a few revisions.
- May 8th, 2013 (03:35pm - 04:35pm)
- Seminar: Center for Dynamics and Geometry Seminar
Title: Singularly beautiful algebraic curves
Speaker: Joel Langer, Case Western Reserve University
Location: MB114The theorems of Gauss on constructible n-gons and Abel on uniform subdivision of the Bernoulli lemniscate place the circle and lemniscate among only a handful of algebraic curves known to possess such nice subdivision properties. For these curves, unit speed parameterization (or its norm) extends to meromorphic (elementary or elliptic) functions on the complex plane. Such parameterizations are already rare, as may be seen from the polyhedral geometry on a (complex) curve C; this is de ned via the quadratic di erential on C induced by dx^2 +dy^2. The required behavior of this quadratic di erential forces rather special singularities of C and it follows, e.g., that Bernoulli lemniscates are the only curves of degree at most four with compact polyhedral geometry. In this talk, such results and related examples will be illustrated via a graphical technique for visualizing the (real) foci and polyhedral geometry of an algebraic curve.
- May 13th, 2013 (10:00am - 12:00pm)
- Seminar: Ph.D. Thesis Defense
Title: "An Analytical Approach for Sustainable Transportation Network Design"
Speaker: Ke han, Adviser: Alberto Bressan, Penn State
Location: MB106
Abstract: http://This dissertation work emphasizes the modeling and formulation of multi-agent, dynamic, interdependent, complex and competitive transportation systems, by invoking mathematically canonical and tractable forms. The design and management of a transportation network include not only problems of adding/removing capacity by changing nodes and arc sets, but also the determination of piecewise smooth decision variables like prices, tolls, traffic signals, information accessibility, and other control variables associated with Stackelberg mechanisms and so-called second-best strategies. The primary modeling paradigm employed by this dissertation is differential Nash-like game among travelers that captures several key aspects of modern traffic networks, including travel choices, travel modes, economic, social and environmental impacts. The well-known concept of dynamic network user equilibrium developed in the early 1990s has been extended in this dissertation to incorporate elastic travel demands and bounded rationality. Several network traffic flow models, including the Lighthill-Whitham-Richards hydrodynamic model featuring vehicle spillback, have been analyzed along with their qualitative properties and numerical results presented. As applications of the aforementioned theoretical work, several network design problems, such as congestion pricing and dynamic signal control, are presented. These problems explicitly address environmental sustainability in a mathematically tractable way. The results reveal various types of complexity inherent in the transportation networks, and provide insights into the management of such systems.