On designing safe and flexible embedded DSLs with Java 5

Although embedded DSLs are widely used in both functional and dynamic languages they are yet to be widely accepted in the Java community. The best available examples are projects like jMock and Hibernate Criteria Query. In this paper we introduce the design of three novel practical embedded DSLs that we designed to showcase the power of Java language and specifically the changes introduced in Java 5. One of those DSLs is fully implemented as an open source project and is gathering momentum in the community. We proceed to discuss the approaches that allow designing safe and flexible DSLs by extracting generic patterns where possible and describing more specific idioms where necessary. It is our goal that this paper would serve as a starting point for someone designing an embedded DSL that takes full advantage of the Java 5 features.     

Constructive semantics for instantaneous reactions

This paper presents some results towards a game-theoretic account of the constructive semantics of step responses for synchronous languages, providing a coherent semantic framework encompassing both non-deterministic Statecharts (as per Pnueli & Shalev) and deterministic esterel. In particular, it is shown that esterel arises from a finiteness condition on strategies whereas Statecharts permits infinite games. Beyond giving a novel and unifying account of these concrete languages the paper sketches a general theory for obtaining different notions of constructive responses in terms of winning conditions for finite and infinite games and their characterisation as maximal post-fixed points of functions in directed complete lattices of intensional truth-values.     

Discrete retardance second harmonic generation ellipsometry

A new instrument was constructed to perform discrete retardance nonlinear optical ellipsometry (DR-NOE). The focus of the design was to perform second harmonic generation NOE while maximizing sample and application flexibility and minimizing data acquisition time. The discrete retardance configuration results in relatively simple computational algorithms for performing nonlinear optical ellipsometric analysis. NOE analysis of a disperse red 19 monolayer yielded results that were consistent with previously reported values for the same surface system, but with significantly reduced acquisition times.     

A simple Hebbian/anti-Hebbian network learns the sparse, independent components of natural images

Slightly modified versions of an early Hebbian/anti-Hebbian neural network are shown to be capable of extracting the sparse, independent linear components of a prefiltered natural image set. An explanation for this capability in terms of a coupling between two hypothetical networks is presented. The simple networks presented here provide alternative, biologically plausible mechanisms for sparse, factorial coding in early primate vision.     

Polynomial eigenfunctions of the exchange operator on the Fermi sphere

A complete set of eigenfunctions of the exchange operator for the (quasiparticle) scattering on the Fermi sphere is developed. The functions are simultaneously bipolynomials in the Landau variables (q/p _F )² and cos _L and in the Abrikosov-Khalatnikov variables cos and cos of the same degree. A parametrization of the quasiparticle scattering amplitude with the aid of these functions includes thes, sp, and effective potential approximations as special cases but is completely general.     

Resistivity anomaly in thin Bi wires: Possibility of a one-dimensional quantum size effect

Thin Bi single-crystal wires down to ~0.2 m in diameter were prepared by pressing liquid Bi into fine Pyrex capillaries. Electron microphotographs were taken to determine the diameter of the wires. Anisotropic magnetoresistance together with Shubnikov-de Haas oscillations were observed at helium temperatures. An anomalous drop in resistivity (T) was found at T < 50 K. Possible explanations are considered, including one based on the quantum size effect.Work performed under the auspices of the U.S. Department of Energy.