Two Decades of Maude

This paper is a tribute to José Meseguer, from the rest of us in the Maude team, reviewing the past, the present, and the future of the language and system with which we have been working for around two decades under his leadership. After reviewing the origins and the language's main features, we present the latest additions to the language and some features currently under development. This paper is not an introduction to Maude, and some familiarity with it and with rewriting logic are indeed assumed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Variant-Based Satisfiability

Although different satisfiability decision procedures can be combined by algorithms such as those of Nelson-Oppen or Shostak, current tools typically can only support a finite number of theories to use in such combinations. To make SMT solving more widely applicable, generic satisfiability algorithms that can allow a potentially infinite number of decidable theories to be user-definable, instead of needing to be built in by the implementers, are highly desirable. This work studies how folding variant narrowing, a generic unification algorithm that offers good extensibility in unification theory, can be extended to a generic variant-based satisfiability algorithm for the initial algebras of its user-specified input theories when such theories satisfy Comon-Delaune's finite variant property (FVP) and some extra conditions. Several, increasingly larger infinite classes of theories whose initial algebras enjoy decidable variant-based satisfiability are identified, and a method based on descent maps to bring other theories into these classes and to improve the generic algorithm's efficiency is proposed and illustrated with examples.Partially supported by NSF Grant CNS 13-19109.Ope

The impacts of personal stress upon critical project decision making in construction

The range of responsibilities for construction managers has become increasingly complex due to additional legal requirements and more widespread stakeholder involvements. These additional pressures potentially impact on the integrity of managers’ decisions when advancing building projects safely and efficiently. The aim of the study is to develop a greater understanding of the direct and indirect effects of work stress upon the critical decision making practice of those charged with significant responsibility in construction projects. Fifty-five questionnaires and a further five interviews were completed by construction project development managers to test and ascertain the hypothesis: “What are the effects of accumulated personal stress buildup upon important project decision making and how can this be managed by construction managers?” The results of the survey indicated that stress is highly subjective and not readily assigned to specific decision making impacts for all managers. However, in terms of the mitigation of stress upon decisions, the results of this study revealed that decision confidence in relation to managerial support had the greatest overall influence upon decision clarity and outcome

Inspecting Maude Variants with GLINTS

[EN] This paper introduces GLINTS, a graphical tool for exploring variant narrowing computations in Maude. The most recent version of Maude, version 2.7.1, provides quite sophisticated unification features, including order-sorted equational unification for convergent theories modulo axioms such as associativity, commutativity, and identity. This novel equational unification relies on built-in generation of the set of variants of a term t, i.e., the canonical form of t sigma for a computed substitution sigma. Variant generation relies on a novel narrowing strategy called folding variant narrowing that opens up new applications in formal reasoning, theorem proving, testing, protocol analysis, and model checking, especially when the theory satisfies the finite variant property, i.e., there is a finite number of most general variants for every term in the theory. However, variant narrowing computations can be extremely involved and are simply presented in text format by Maude, often being too heavy to be debugged or even understood. The GLINTS system provides support for (i) determining whether a given theory satisfies the finite variant property, (ii) thoroughly exploring variant narrowing computations, (iii) automatic checking of node embedding and closedness modulo axioms, and (iv) querying and inspecting selected parts of the variant trees.This work has been partially supported by EU (FEDER) and Spanish MINECO grant TIN 2015-69175-C4-1-R and by Generalitat Valenciana PROMETEO-II/2015/013. Angel Cuenca-Ortega is supported by SENESCYT, Ecuador (scholarship program 2013), and Julia Sapina by FPI-UPV grant SP2013-0083. Santiago Escobar is supported by the Air Force Office of Scientific Research under award number FA9550-17-1-0286.Alpuente Frasnedo, M.; Cuenca-Ortega, A.; Escobar Román, S.; Sapiña-Sanchis, J. (2017). Inspecting Maude Variants with GLINTS. Theory and Practice of Logic Programming. 17(5-6):689-707. https://doi.org/10.1017/S147106841700031XS689707175-

Design, crime and the built environment

Crime Prevention through Environmental Design (CPTED) is a method of reducing crime through the design and manipulation of the built environment. Based upon the Opportunity Theories of crime, CPTED focuses upon blocking opportunities for criminal behaviour through subtle techniques to maximise informal surveillance, guardianship and maintenance, to minimise through movement and to set standards of physical security that are proportionate to crime risk. This chapter will discuss the principles of CPTED and the theories from which it evolved. It will explore the effectiveness of these principles, both individually and combined, in reducing crime, before exploring how CPTED is applied in practice

In-Plane Spectral Weight Shift of Charge Carriers in YBa2Cu3O6.9YBa_2Cu_3O_{6.9}

The temperature dependent redistribution of the spectral weight of the $CuO_2$ plane derived conduction band of the $YBa_2Cu_3O_{6.9}$ high temperature superconductor (T_c = 92.7 K) was studied with wide-band (from 0.01 to 5.6 eV) spectroscopic ellipsometry. A superconductivity - induced transfer of the spectral weight involving a high energy scale in excess of 1 eV was observed. Correspondingly, the charge carrier spectral weight was shown to decrease in the superconducting state. The ellipsometric data also provide detailed information about the evolution of the optical self-energy in the normal and superconducting states

Distributions of inherent structure energies during aging

We perform extensive simulations of a binary mixture Lennard-Jones system subjected to a temperature jump in order to study the time evolution of fluctuations during aging. Analyzing data from 1500 different aging realizations, we calculate distributions of inherent structure energies for different aging times and contrast them with equilibrium. We find that the distributions initially become narrower and then widen as the system equilibrates. For deep quenches, fluctuations in the glassy system differ significantly from those observed in equilibrium. Simulation results are partially captured by theoretical predictions only when the final temperature is higher than the mode coupling temperature.Comment: 5 pages, 4 figure

Income Disparity and Economic Growth: Evidence from China

This paper carries out a pilot empirical study on how income inequality affects growth and the macro economy by means of incorporating panel data information into a macro-econometric model. China is used as the pilot field. Provincial urban and rural household data are used to construct inequality measures, which are then used to augment household consumption equations in the ADB China model. Model simulations are performed to study the effect of inequality on GDP growth and its sectoral components. Results show that inequality is a robust explanatory variable of consumption and that the way inequality develops over time carries certain negative consequences on GDP and sectoral growth.Income inequality, Growth, Econometric model, China