Parallel Supercomputer Simulations for Education

A summary of work for the the NSF project `Integration of Information Age Networking and Parallel Supercomputer Simulations into University General Science and K-12 Curricula' as of March 1997.

Introduction

The PSSE project is a MRA (metacenter regional alliance) between Cornell University and Syracuse University. The Syracuse the collaborators are the Department of Physics, the College of Engineering and Comnputer Science, and the Northeast Parallel Architectures Center (NPAC); the Cornell collaborators and the Department of Physics and the School of Civil and Environmental Engineering. Together, we are developing four educational modules incorporating advanced scientific simulations. Each module focuses on an area where simulations using high-performance computers are the driving force behind current research. We have selected Web technologies, and Java in particular, as a way of presenting our work.

Each module is being developed by a separate team, two at Syracuse and two at Cornell. We regularly meet to exchange ideas and discuss technology, issues of user interaction, and style common to all modules. The modules are: membranes; fluid dynamics; crack propagation in societal structures; and avalanches, hysteresis, and crackling noises. All four teams have research interests in the subject or their module. Further details of the projects aims are given in our project description. Below we illustrate the current work on each of the four modules and link to some demonstration and prototype examples.

Membrane fluctuations

The Syracuse Physics team, led by Prof. Ed Lipson and Prof. Simon Catterall, are developing material on the properties of two-dimensional interfaces and membranes. They are using text, images, Java applets and remote simulation.

Membranes may be split into two categories: crystalline and fluid. Crystalline membranes have a fixed connectivity like a set of springs connected together as a mesh, the spectrin network of a red blood cell, or a sheet of rubber. The properties are controlled by competition between elastic (stretching) terms and bending terms. Our first applet models a simple, and fairly abstract, segment of membrane represented by a small triangulation. The student will be able to see how the membrane is either flat or crumpled depending on its stiffness (strength of the bending term).
[ larger image | applet ]


[ larger image | applet ]		 Fluid membranes do not have a fixed connectivity, that is the components of the membrane are fluid within the membrane. Physical systems include amphiphilic bilayers such as detergents and cell membranes. It also turns out that these models may help us to understand theories of quantum gravity.

In addition to simulations of membranes we are developing applets that help illustrate the concepts underlying or models. Here we illustrate a simple spring as used to model the elastic properties of crystalline membranes. The applet plots the force and stored energy of a spring as the user changes the extension.
[ larger image | applet ]


[ larger image | applet ]		 Many of the concepts in membrane physics are quite hard to understand and we hope to tie the abstract simulations to `real examples' as much as possible. We focus on the human red blood cell as a particularly nice example. The applet illustrated here is simply an interactive picture of a red blood cell; the user can rotate the model to examine the shape.

Fluid dynamics

Led by Prof. Hiroshi Higuchi, members of the College of Engineering and Computer Science at Syracuse are developing the fluid dynamics module. Their focus is on the exploration and understanding of essential physical aspects of fluid flows in common applications and in nature.

The applet illustrated here allows the `experimenter' to investigate the flows created by the superposition of basic flow elements. This will be incorporated in a laboratory style part of the module where the user is asked to try particular configurations and then look at a discussion of the expected results.
[ larger image ]


[ larger image ]		 This applet not only shows the flows lines created by the superposition of basic flow elements, but also allows a set of markers to be injected and then flow in real time.

Hysteresis and avalanche behavior

The Cornell Physics team, led by Prof. Jim Sethna, are developing the hysteresis module. To date they have focused on developing a comprehensive applet to simulate hysteresis in 2-, 3- and 4-dimensional magnetic spin systems.

The hysteresis applet illustrated here can be configured in a multitude of ways to control the dimensionality of the spin system, it size, and simulation details. The applet plots the hysteresis loop as the simulation proceeds. It is worth noting that these `little models' (of order 100000 spins) push the limits of current Java implementations and browser systems.
[ larger image | applet]


[ larger image ]		 Individual avalanches can be drawn and colored to show propagation of the avalanche trough the sample.

Crack propagation

Led by Prof. Tony Igraffea, members of the Cornell Fracture Group are developing the crack propagation module. They are using Java to provide an effective front-end to a remote 2-dimensional crack propagation simulation code (FRANC2D). The module links such simulations to societal structures -- structures whose performance (including catastrophic failure) has a large impact on a significant population.

Photographs, diagrams and precomputed simulation results are used to illustrate the module and link to societal structures in particular
[ larger image ]


[ larger image ]		 Here we illustrate the first step in using the simulation interface: the user draws the shape to be simulated.

Part of the remote FRANC2D code automatically generates a simulation mesh which is then redisplayed by the applet. The user then adds forces, constraints and an embryonic crack (direction shown by green line).
[ larger image ]


[ larger image ]		 The completed specification is sent back to the server and scripts are used to run the FRANC2D simulation. When the simulation is complete, the results are displayed by the same applet used to enter the specification. Various display options are provided, along with zoom and pan functions.

How does the PSSE project fit in with other work at Syracuse?

The Physics Department has used the Web to deliver interactive simulations for some time; first with CGI scripts and now with Java. The innovative general science class PHY105/106 helped spawn two current projects: the PSSE MRA (this project) and the CCD project.

As we have illustrated with examples of current work above, the MRA is split into four modules, two at Syracuse and two at Cornell. While the MRA work has a much broader target than just undergraduates, we hope to use some of the material in the PHY105/106 course.
The CCD (NSF Course Curriculum Development) project is specifically targeted at developing material for use in undergraduate courses. As such, the CCD work is very closely related to the PHY105/106 course. Further details can be found on the CCD page

[ Up | Contacts | Department of Physics, Syracuse University ]

This page is maintained by Simeon Warner
Last updated 2 April 1997