Tycho Brahe's Portrait

The Tycho User Interface System

Tycho is the next-generation user-interface system we are building for the Ptolemy project. It is a complete [incr Tcl] application structured as an extensible class library. Our goal is to make it easy to extend this basic application with functionality and a user interface for specialized applications such as electronic design and simulation. The Tycho library includes a selection of general-...

Portrait

Born in 1944, I grew up in a world in which polio was both a gripping fear and real threat. Then in a matter of a few years-polio was eradicated by a vaccine developed by Jonas Salk. Later I learned that Salk's efforts were built on pioneering work of many others, including John Enders, Thomas Weller and Frederick Robbins (Nobelists, 1954), and David Bodian, who pioneered studies of polio patho...

Elementary Gates for Quantum Computation Tycho Sleator

We show that a set of gates that consists of all one-bit quantum gates (U(2)) and the two-bit exclusive-or gate (that maps Boolean values (x; y) to (x; xy)) is universal in the sense that all unitary operations on arbitrarily many bits n (U(2 n)) can be expressed as compositions of these gates. We investigate the number of the above gates required to implement other gates, such as generalized D...

Google Portrait

Comparing Tycho–2 Astrometry with Ucac1

The Tycho–2 Catalogue, released in February 2000, is based on the ESA Hipparcos space mission data and various ground–based catalogs for proper motions. An external comparison of the Tycho–2 astrometry is presented here using the first U.S. Naval Observatory CCD As-trograph Catalog (UCAC1). The UCAC1 data were obtained from observations performed at CTIO between February 1998 and November 1999,...