Single-valuedness of tree transducers is decidable in polynomial time

AbstractA bottom-up finite-state tree transducer (FST) A is called single-valued iff for every input tree there is at most one output tree.We give a polynomial-time algorithm which decides whether or not a given FST is single-valued. The algorithm is based on:•the freedom of the submonoid of trees which contain at least one occurrence of one variable ∗;•the succinct representation of trees by graphs;•a sequence of normalizing transformations of the given transducer; and•a polynomially decidable characterization of pairs of equivalent output functions.We apply these methods to show that finite-valuedness is decidable in polynomial time as well

Visibly Pushdown Transducers with Well-nested Outputs

Visibly pushdown transducers (VPTs) are visibly pushdown automata extended with outputs. They have been introduced to model transformations of nested words, i.e. words with a call/return structure. When outputs are also structured and well nested words, VPTs are a natural formalism to express tree transformations evaluated in streaming. We prove the class of VPTs with well-nested outputs to be decidable in PTIME. Moreover, we show that this class is closed under composition and that its type-checking against visibly pushdown languages is decidable

Tree Transducers and Formal Methods (Dagstuhl Seminar 13192)

The aim of this Dagstuhl Seminar was to bring together researchers from various research areas related to the theory and application of tree transducers. Recently, interest in tree transducers has been revived due to surprising new applications in areas such as XML databases, security verification, programming language theory, and linguistics. This seminar therefore aimed to inspire the exchange of theoretical results and information regarding the practical requirements related to tree transducers

Subtree replacement systems

Theory and computer applications of subtree replacement system

Foundations of Software Science and Computation Structures

This open access book constitutes the proceedings of the 22nd International Conference on Foundations of Software Science and Computational Structures, FOSSACS 2019, which took place in Prague, Czech Republic, in April 2019, held as part of the European Joint Conference on Theory and Practice of Software, ETAPS 2019. The 29 papers presented in this volume were carefully reviewed and selected from 85 submissions. They deal with foundational research with a clear significance for software science

Tree Automata Techniques and Applications

International audienc

Masonry nonlinear response: modeling and analysis of the effects of damaging mechanisms

Over the last decades, many efforts were devoted to develop efficient and accurate numerical procedures for the assessment of the structural capacity of masonry constructions. The main difficulties in modeling this type of material are due to its heterogeneous nature. Indeed, masonry is composed by blocks, stones or bricks, connected with or without mortar, whose geometry, mechanical properties and arrangement strongly affect the overall response. Among the available modeling strategies, finite element models appear to be suitable tools to describe the evolution of the nonlinear mechanisms developing in the material under typical loading conditions. Within this framework, macromechanical models, which consider masonry as an equivalent homogeneous, isotropic or anisotropic medium, are a fair compromise between accuracy and computational burden. Stemming on the above considerations, this work focuses on the development of constitutive laws involving damage and plasticity inner variables, tailored to the macromechanical analysis of 2D masonry structures. Herein, a new isotropic damage-plastic model, which is an enhanced version of that presented by Addessi et al. (2002), is proposed. This model is able to capture the degrading mechanisms due to propagation of microcracks and accumulation of irreversible strains, as well as the stiffness recovery related to cracks re-closure. Moreover, to account for the variation of the mechanical properties in the different material directions, a novel orthotropic damage model is developed to deal with regular masonry textures. The proposed models are implemented in finite element procedures, where the mesh-dependency problem is efficiently overcome by adopting nonlocal integral formulations. Numerical applications are performed to assess the models capacity of describing the material inelastic behavior and comparisons of numerically and experimentally evaluated responses are also provided for some masonry panels. Finally, the effects of degrading mechanisms on masonry dynamic behavior are investigated. For this purpose a systematic approach is adopted, based on the evaluation of the frequency response curves of masonry walls. The obtained curves show peculiar characteristics due to the irreversible effect of damage, which leads to degradation of the structural mechanical properties and the related variation of the natural frequencies, which in turn significantly influence the dynamic amplification of the response. The numerical results are also confirmed by shaking table tests performed on tuff masonry walls loaded out-of-plane

Collected Papers in Structural Mechanics Honoring Dr. James H. Starnes, Jr.

This special publication contains a collection of structural mechanics papers honoring Dr. James H. Starnes, Jr. presented at the 46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference held in Austin, Texas, April 18-21, 2005. Contributors to this publication represent a small number of those influenced by Dr. Starnes' technical leadership, his technical prowess and diversity, and his technical breath and depth in engineering mechanics. These papers cover some of the research areas Dr. Starnes investigated, which included buckling, postbuckling, and collapse of structures; composite structural mechanics, residual strength and damage tolerance of metallic and composite structures; and aircraft structural design, certification and verification. He actively pursued technical understanding and clarity, championed technical excellence, and modeled humility and perseverance