12,776 research outputs found
Phase behaviour of a symmetrical binary fluid mixture
We have investigated the phase behaviour of a symmetrical binary fluid
mixture for the situation where the chemical potentials and of
the two species differ. Attention is focused on the set of interparticle
interaction strengths for which, when , the phase diagram exhibits
both a liquid-vapor critical point and a tricritical point. The corresponding
phase behaviour for the case is investigated via
integral-equation theory calculations within the mean spherical approximation
(MSA), and grand canonical Monte Carlo (GCMC) simulations. We find that two
possible subtypes of phase behaviour can occur, these being distinguished by
the relationship between the critical lines in the full phase diagram in the
space of temperature, density, and concentration. We present the detailed form
of the phase diagram for both subtypes and compare with the results from GCMC
simulations, finding good overall agreement. The scenario via which one subtype
evolves into the other, is also studied, revealing interesting features.Comment: 22 pages, 13 figure
Toward Isomorphism of Intersection and Union types
This paper investigates type isomorphism in a lambda-calculus with
intersection and union types. It is known that in lambda-calculus, the
isomorphism between two types is realised by a pair of terms inverse one each
other. Notably, invertible terms are linear terms of a particular shape, called
finite hereditary permutators. Typing properties of finite hereditary
permutators are then studied in a relevant type inference system with
intersection and union types for linear terms. In particular, an isomorphism
preserving reduction between types is defined. Type reduction is confluent and
terminating, and induces a notion of normal form of types. The properties of
normal types are a crucial step toward the complete characterisation of type
isomorphism. The main results of this paper are, on one hand, the fact that two
types with the same normal form are isomorphic, on the other hand, the
characterisation of the isomorphism between types in normal form, modulo
isomorphism of arrow types.Comment: In Proceedings ITRS 2012, arXiv:1307.784
Using Inhabitation in Bounded Combinatory Logic with Intersection Types for Composition Synthesis
We describe ongoing work on a framework for automatic composition synthesis
from a repository of software components. This work is based on combinatory
logic with intersection types. The idea is that components are modeled as typed
combinators, and an algorithm for inhabitation {\textemdash} is there a
combinatory term e with type tau relative to an environment Gamma?
{\textemdash} can be used to synthesize compositions. Here, Gamma represents
the repository in the form of typed combinators, tau specifies the synthesis
goal, and e is the synthesized program. We illustrate our approach by examples,
including an application to synthesis from GUI-components.Comment: In Proceedings ITRS 2012, arXiv:1307.784
Design of an air traffic computer simulation system to support investigation of civil tiltrotor aircraft operations
This research project addresses the need to provide an efficient and safe mechanism to investigate the effects and requirements of the tiltrotor aircraft's commercial operations on air transportation infrastructures, particularly air traffic control. The mechanism of choice is computer simulation. Unfortunately, the fundamental paradigms of the current air traffic control simulation models do not directly support the broad range of operational options and environments necessary to study tiltrotor operations. Modification of current air traffic simulation models to meet these requirements does not appear viable given the range and complexity of issues needing resolution. As a result, the investigation of systemic, infrastructure issues surrounding the effects of tiltrotor commercial operations requires new approaches to simulation modeling. These models should be based on perspectives and ideas closer to those associated with tiltrotor air traffic operations
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