A program checker verifies that a particular program execution is correct. We give simple and efficient program checkers for some basic geometric tasks. We report about our experiences with program checking in the context of the LEDA system. We discuss program checking for data structures that have to rely on user-provided functions.

Using well-defined selection criteria applied to the LEDA galaxy catalogue we have constructed a sample of elliptical galaxies that can be taken to lie in the field. Such criteria can easily be applied to theoretical simulations for direct comparison with observations. The variation of the number of ‘isolated’ ellipticals with selection criteria is also investigated. A preliminary study of the ...

OFFIS and Politecnico di Milano. This document may be copied freely for use in the public domain. Sections of it may be copied provided that acknowledgement is given of this original work. No responsibility is assumed by the REQUEST Project or its members for application or design, nor for any infringements of patents or rights of others which may result from the use of this document. Preface—T...

This paper critically examines Jerry Fodor’s latest attacks on evolutionary psychology. Contra Leda Cosmides and John Tooby, Fodor argues (i) there is no reason to think that human cognition is a Darwinian adaptation in the first place, and (ii) there is no valid inference from adaptationism about the mind to massive modularity. However, Fodor maintains (iii) that there is a valid inference in ...

The orders-of-magnitude higher luminosities required by future electron–ion collider concepts require a dissipative force to counteract the numerous factors acting to gradually increase the phase space volume of relativistic ion beams. High-energy electron cooling systems could provide the necessary dissipation via dynamical friction, but will have to be designed for new parameter regimes. It i...

A new dynamic friction model for modeling of elliptical vibration assisted turning (EVAT) was developed in this research. The periodic change of the friction force direction is known to be one of the most important causes of this phenomenon. In modeling of machining processes (including the EVAT process), static Coulomb friction model was employed by most of the researchers. Because of the peri...

Adhesion level for the proper running of rail wheelset on track has remained a significant problem for researchers in detecting slippage to avoid accidents. In this paper, the slippage of rail wheels has been observed applying forward and lateral motions to slip velocity and torsion motion. The longitudinal and lateral forces behavior is watched with respect to traction force to note correlatio...

nowadays the surface texturing has been widely recognized as a usable capability to improve the tribological systems. in this paper, ultrasonic assisted turning (uat) isperformed to create the micro textures on the flat faces. micro surface texturing ismade on the al7075-t6 by the uat in the face turning process. then, the influences of cutting speed feed, vibration direction and vibration ampl...