Spatial navigation model based on chaotic attractor networks

We present a model of spatial navigation based on the non-convergent dynamics of brain activity. The system includes a hippocampal module that processes global spatial information and a cortical module that deals with local sensory information. We test the model using several spatial navigation paradigms: goal finding, shortcutting and detouring. Computer simulations show that the performance of the agent qualitatively matches that of animals and related models. This new approach provides a novel interpretation of how the brain accomplishes spatial navigation.     

Fabrication and characterization of magnetic cotton yarns for textile applications

Cotton yarns covered with hard (barium hexaferrite – BaFe), and soft (Black Toner 6745 CP-313) magnetic particles are investigated for their application in the field of functional textile. Our results reveal a rather consistent dependence of the magnetic yarn properties on the fabrication parameters (nature of the magnetic powder, composition of the coating solution, etc.). The magnetic properties (residual magnetism and coercive field intensity) of the yarns are increasing with the magnetic powder content in the coating solution. However, this is at some point leading to the degradation of some yarn properties, e.g. elasticity. Bending tests revealed that several factors improve the bending behavior of the yarns and reduce cracks. For example, a higher number of cracks were exhibited by the hard magnetic yarns compared to the soft ones. The presence of polyurethane in the coating solution leads to no cracks on the surface of hard magnetic yarns or a small number in case of soft magnetic yarns. The tensile properties of the magnetic yarns are increasing with increasing magnetic powder content. Over a certain mass percentage (45% for BaFe and 30% for CP-313), the magnetic yarns tensile strength and elongation become lower than those of the support yarn.     

An Implicit Runge–Kutta Method for Integration of Differential Algebraic Equations of Multibody Dynamics

When performing dynamic analysis of a constrained mechanical system, aset of index 3 Differential Algebraic Equations (DAE) describes the timeevolution of the model. This paper presents a state space DAE solutionframework that can embed an arbitrary implicit Ordinary DifferentialEquations (ODE) code for numerical integration of a reduced set of statespace ordinary differential equations. This solution framework isconstructed with the goal of leveraging with minimal effort establishedoff the shelf implicit ODE integrators for efficiently solving the DAEof multibody dynamics. This concept is demonstrated by embedding awell-known public domain singly diagonal implicit Runge–Kutta code inthe framework provided. The resulting L-stable, stiffly accurateimplicit algorithm is shown to be two orders of magnitude faster than astate of the art explicit algorithm when used to simulate a stiffvehicle model.     

A Rewriting Calculus for Cyclic Higher-order Term Graphs

Introduced at the end of the nineties, the Rewriting Calculus (ρ-calculus, for short) is a simple calculus that fully integrates term-rewriting and λ-calculus. The rewrite rules, acting as elaborated abstractions, their application and the obtained structured results are first class objects of the calculus. The evaluation mechanism, generalizing beta-reduction, strongly relies on term matching in various theories.In this paper we propose an extension of the ρ-calculus, handling graph like structures rather than simple terms. The transformations are performed by explicit application of rewrite rules as first class entities. The possibility of expressing sharing and cycles allows one to represent and compute over regular infinite entities.The calculus over terms is naturally generalized by using unification constraints in addition to the standard ρ-calculus matching constraints. This therefore provides us with the basics for a natural extension of an explicit substitution calculus to term graphs. Several examples illustrating the introduced concepts are given.     

SO2 and NOx removal by electron beam and electrical discharge induced non-thermal plasmas

An installation containing a DC negative corona discharge reactor, a pulse corona discharge reactor and a combined electron beam and microwave induced plasma reactor is presented. SO₂ is removed up to 42% through spontaneous reaction with ammonia without electron beam or microwave irradiation at the temperature below 70 °C. For the same removal efficiency of 98% for SO₂ and 80% for NO_x at separate EB irradiation of 40 kGy, the required absorbed dose is about two times smaller for simultaneous electron beam and microwave irradiation. The SO₂ removal efficiency of simultaneous DC or positive discharge and microwave discharge is higher than separate DC, pulse and MW discharge. Also, the applied voltage level at which the removal efficiency reaches the maximum value is less than for the separate application of DC or pulse discharge. The NO_x removal efficiency of DC or pulse discharge suffers little change by additional use of the microwave energy.     

From Functional Programs to Interaction Nets via the Rewriting Calculus

We use the ρ-calculus as an intermediate language to compile functional languages with pattern-matching features, and give an interaction net encoding of the ρ-terms arising from the compilation. This encoding gives rise to new strategies of evaluation, where pattern-matching and 'traditional' β-reduction can proceed in parallel without overheads.     

Anti-patterns for rule-based languages

Negation is intrinsic to human thinking and most of the time when searching for something, we base our patterns on both positive and negative conditions. This should be naturally reflected in software that provide pattern-based searches. We would like for example to specify that we search for white cars that are not station wagons, or that we search for a list of objects that does not contain two identical elements.     

Translating Combinatory Reduction Systems into the Rewriting Calculus

The last few years have seen the development of the rewriting calculus (or rho-calculus, ρCal) that extends first order term rewriting and λ-calculus. The integration of these two latter formalisms has been already handled either by enriching first-order rewriting with higher-order capabilities, like in the Combinatory Reduction Systems, or by adding to λ-calculus algebraic features. The different higher-order rewriting systems and the rewriting calculus share similar concepts and have similar applications, and thus, it seems natural to compare these formalisms. We analyze in this paper the relationship between the Rewriting Calculus and the Combinatory Reduction Systems and we present a translation of CRS-terms and rewrite rules into rho-terms and we show that for any CRS-reduction we have a corresponding rho-reduction.     

Expressing combinatory reduction systems derivations in the rewriting calculus

The last few years have seen the development of the rewriting calculus (also called rho-calculus or ρ-calculus) that uniformly integrates first-order term rewriting and the λ-calculus. The combination of these two latter formalisms has been already handled either by enriching first-order rewriting with higher-order capabilities, like in the Combinatory Reduction Systems (CRS), or by adding to the λ-calculus algebraic features. The various higher-order rewriting systems and the rewriting calculus share similar concepts and have similar applications, and thus, it is important to compare these formalisms to better understand their respective strengths and differences. We show in this paper that we can express Combinatory Reduction Systems derivations in terms of rewriting calculus derivations. The approach we present is based on a translation of each possible CRS-reduction into a corresponding ρ-reduction. Since for this purpose we need to make precise the matching used when evaluating CRS, the second contribution of the paper is to present an original matching algorithm for CRS terms that uses a simple term translation and the classical matching of lambda terms.