Why Do We Believe in the Second Law?

Claims of exceptions to the second law of thermodynamics are generally met with extreme skepticism that is quite reasonable given the great confidence placed in the second law. But what specifically is the basis for that confidence? The perspective from which we approach experimental or theoretical results that call into question the absolute status of the second law depends greatly on our understanding of why it must be true. For example, a belief that there are solid theoretical arguments demonstrating that the second law must be true leads to a very different perspective than a belief that the law is simply a generalization of empirical observations. This paper will briefly survey and examine some of the basic arguments on which our confidence in the second law might be based, to help provide a well-informed perspective for evaluating the various claims presented at this conference.Comment: 6 pages, to appear in Proc. of "First International Conference on Quantum Limits to the Second Law," July 2002, editor D.P. Sheeha

Dynamic Multilevel Graph Visualization

We adapt multilevel, force-directed graph layout techniques to visualizing dynamic graphs in which vertices and edges are added and removed in an online fashion (i.e., unpredictably). We maintain multiple levels of coarseness using a dynamic, randomized coarsening algorithm. To ensure the vertices follow smooth trajectories, we employ dynamics simulation techniques, treating the vertices as point particles. We simulate fine and coarse levels of the graph simultaneously, coupling the dynamics of adjacent levels. Projection from coarser to finer levels is adaptive, with the projection determined by an affine transformation that evolves alongside the graph layouts. The result is a dynamic graph visualizer that quickly and smoothly adapts to changes in a graph.Comment: 21 page

C++ Templates as Partial Evaluation

This paper explores the relationship between C++ templates and partial evaluation. Templates were designed to support generic programming, but unintentionally provided the ability to perform compile-time computations and code generation. These features are completely accidental, and as a result their syntax is awkward. By recasting these features in terms of partial evaluation, a much simpler syntax can be achieved. C++ may be regarded as a two-level language in which types are first-class values. Template instantiation resembles an offline partial evaluator. This paper describes preliminary work toward a single mechanism based on Partial Evaluation which unifies generic programming, compile-time computation and code generation. The language Catat is introduced to illustrate these ideas.Comment: 13 page