Outline of a Calculus of Type Subsumption

This paper is a brief analysis of the notion of syntactic representation of types followed by a proposal of a formal calculus of type subsumption. The idea which is developed centers on the concept of indexed term, an extension of the definition of algebraic terms relaxing the fixed arity and fixed indexing constraints, and which allows term symbols to have some pre-order structure. It is shown that the structure on the set of symbols can be homomorphically extended to indexed terms to what is defined to be a subsumption ordering. Furthermore, when symbols have a lattice structure, this structure extends to a lattice of indexed terms. The notions of unification and generalization are also shown to fit the extension, and constitute the meet and join operations

Optimization of Band Gap and Thickness for the Development of Efficient n-i-p+ Solar Cell

By using an electrical-optical AMPS-1D program (One Dimensional Analysis of Microelectronic and Photonic structures), a n-i-p type solar cell, based on hydrogenated amorphous silicon (a-Si : H) and hydrogenated nanocrystalline silicon oxide (nc-SiOx : H) has been investigated and simulated. The numerical analysis describes the modeling of the external cell performances, like, the short-circuit current (JSC), the open circuit voltage (VOC), the fill factor (FF) and efficiency (Eff) with the oxygen content in the p-ncSiOx : H window layer by varying its mobility band gap (Eg) associated simultaneously to the effect of the absorber layer (i-a-Si : H) thickness. Also, the i-a-Si : H absorber layer band gap was optimized. The simulation result shows that the VOC depend strongly on the band offset (ΔEV) in valence band of p-side. But, VOC does not depend on the thickness of the intrinsic layer. However, VOC increases when the energy band gap of the intrinsic layer is higher. It is demonstrated that the highest efficiency of 10.44 % (JSC = 11.67 mA/cm2; FF = 0.829; VOC = 1070 mV) has been obtained when values of p-nc-SiOx : H window layer band gap, i-a-Si : H absorber layer band gap and i-a-Si : H absorber layer thickness are 2.10 eV, 1.86 eV, and 550 nm, respectively

Optimization of Band Gap and Thickness for the Development of Efficient n-i-p+ Solar Cell

By using an electrical-optical AMPS-1D program (One Dimensional Analysis of Microelectronic and Photonic structures), a n-i-p type solar cell, based on hydrogenated amorphous silicon (a-Si : H) and hydrogenated nanocrystalline silicon oxide (nc-SiOx : H) has been investigated and simulated. The numerical analysis describes the modeling of the external cell performances, like, the short-circuit current (JSC), the open circuit voltage (VOC), the fill factor (FF) and efficiency (Eff) with the oxygen content in the p-ncSiOx : H window layer by varying its mobility band gap (Eg) associated simultaneously to the effect of the absorber layer (i-a-Si : H) thickness. Also, the i-a-Si : H absorber layer band gap was optimized. The simulation result shows that the VOC depend strongly on the band offset (ΔEV) in valence band of p-side. But, VOC does not depend on the thickness of the intrinsic layer. However, VOC increases when the energy band gap of the intrinsic layer is higher. It is demonstrated that the highest efficiency of 10.44 % (JSC = 11.67 mA/cm2; FF = 0.829; VOC = 1070 mV) has been obtained when values of p-nc-SiOx : H window layer band gap, i-a-Si : H absorber layer band gap and i-a-Si : H absorber layer thickness are 2.10 eV, 1.86 eV, and 550 nm, respectively

Electrical properties of short period InAs/GaSb superlattice

International audienc

An ACG View on G-TAG and Its g-Derivation

International audienceG-TAG is a Tree Adjoining Grammar (TAG) based formalism which was specifically designed for the task of text generation. Contrary to TAG, the derivation structure becomes primary, as pivot between the conceptual representation and the surface form. This is a shared feature with the encoding of TAG into Abstract Categorial Grammars. This paper propose to study G-TAG from an ACG perspective. We rely on the reversibility property of ACG that makes both parsing and generation fall within a common morphism inversion process. Doing so, we show how to overcome some limitations of G-TAG regarding predicative adjunction and how to propose alternative approaches to some phenomena

A Modular Order-sorted Equational Generalization Algorithm

Generalization, also called anti-unification, is the dual of unification. Given terms t and t , a generalizer is a term t of which t and t are substitution instances. The dual of a most general unifier (mgu) is that of least general generalizer (lgg). In this work, we extend the known untyped generalization algorithm to, first, an order-sorted typed setting with sorts, subsorts, and subtype polymorphism; second, we extend it to work modulo equational theories, where function symbols can obey any combination of associativity, commutativity, and identity axioms (including the empty set of such axioms); and third, to the combination of both, which results in a modular, order-sorted equational generalization algorithm. Unlike the untyped case, there is in general no single lgg in our framework, due to order-sortedness or to the equational axioms. Instead, there is a finite, minimal and complete set of lggs, so that any other generalizer has at least one of them as an instance. Our generalization algorithms are expressed by means of inference systems for which we give proofs of correctness. This opens up new applications to partial evaluation, program synthesis, and theorem proving for typed equational reasoning systems and typed rulebased languages such as ASF+SDF, Elan, OBJ, Cafe-OBJ, and Maude. © 2014 Elsevier Inc. All rights reserved. 1.M. Alpuente, S. Escobar, and J. Espert have been partially supported by the EU (FEDER) and the Spanish MEC/MICINN under grant TIN 2010-21062-C02-02, and by Generalitat Valenciana PROMETEO2011/052. J. Meseguer has been supported by NSF Grants CNS 09-04749, and CCF 09-05584.Alpuente Frasnedo, M.; Escobar Román, S.; Espert Real, J.; Meseguer, J. (2014). A Modular Order-sorted Equational Generalization Algorithm. Information and Computation. 235:98-136. https://doi.org/10.1016/j.ic.2014.01.006S9813623

Observational equivalences for linear logic CC languages

Linear logic Concurrent Constraint programming (LCC) is an extension of concurrent constraint programming (CC) where the constraint system is based on Girard's linear logic instead of the classical logic. In this paper we address the problem of program equivalence for this programming framework. For this purpose, we present a structural operational semantics for LCC based on a label transition system and investigate different notions of observational equivalences inspired by the state of art of process algebras. Then, we demonstrate that the asynchronous \pi-calculus can be viewed as simple syntactical restrictions of LCC. Finally we show LCC observational equivalences can be transposed straightforwardly to classical Concurrent Constraint languages and Constraint Handling Rules, and investigate the resulting equivalences.Comment: 17 page