Belief merging in Dynamic Logic of Propositional Assignments

International audienceWe study syntactical merging operations that are defined semantically by means of the Hamming distance between valuations; more precisely, we investigate the Σ-semantics, Gmax-semantics and max-semantics. We work with a logical language containing merging operators as connectives, as opposed to the metalanguage operations of the literature. We capture these merging operators as programs of Dynamic Logic of Propositional Assignments DL-PA. This provides a syntactical characterisation of the three semantically defined merging operators, and a proof system for DL-PA therefore also provides a proof system for these merging operators. We explain how PSPACE membership of the model checking and satisfiability problem of star-free DL-PA can be extended to the variant of DL-PA where symbolic disjunctions that are parametrised by sets (that are not defined as abbreviations, but are proper connectives) are built into the language. As our merging operators can be polynomially embedded into this variant of DL-PA, we obtain that both the model checking and the satisfiability problem of a formula containing possibly nested merging operators is in PSPACE

Dalal's Revision without Hamming Distance

International audienceA well known strategy for belief revision is the use of an operator which takes as input a belief base and formula and outputs a new consistent revised belief base. Many operators require additional information such as epistemic entrenchment relations, system of spheres, faithful orderings, subformulae relation, etc. However, in many applications this extra information does not exist and all beliefs have to be equally considered. Other operators that can do without background information are dependent on the syntax. Among the few operators that possess both kinds of independence: of extra information and of the syntax, Dalal’s operator is the most outstanding. Dalal’s revision moves from the models of the base to the models of the input formula which are closest in terms of Hamming distance. A drawback of Dalal’s approach is that it fails when faced with inconsistent belief bases. This paper proposes a new method for computing Dalal’s revision that avoids the computation of belief bases models. We propose a new distance between formulae based on distances between terms of formulae in DNF and a revision operator based on these distances. The proposed operator produces Dalal’s equivalent results when the belief base and new input are both consistent. Moreover, this new operator is able to handle inconsistent belief bases. We also analyze several properties of the new operator. While the input belief base and formula need a compilation to DNF, the operator meets desirable properties making the approach suitable for implementation

An application of belief merging for the diagnosis of oral cancer

Machine learning employs a variety of statistical, probabilistic, fuzzy and optimization techniques that allow computers to “learn” from examples and to detect hard-to-discern patterns from large, noisy or complex datasets. This capability is well-suited to medical applications, and machine learning techniques have been frequently used in cancer diagnosis and prognosis. In general, machine learning techniques usually work in two phases: training and testing. Some parameters, with regards to the underlying machine learning technique, must be tuned in the training phase in order to best “learn” from the dataset. On the other hand, belief merging operators integrate inconsistent information, which may come from different sources, into a unique consistent belief set (base). Implementations of merging operators do not require tuning any parameters apart from the number of sources and the number of topics to be merged. This research introduces a new manner to “learn” from past examples using a non parametrised technique: belief merging. The proposed method has been used for oral cancer diagnosis using a real-world medical dataset. The results allow us to affirm the possibility of training (merging) a dataset without having to tune the parameters. The best results give an accuracy of greater than 75%

On the development of a logic calculator: a novel tool to perform logical operations

Abstract. In this paper we propose a Logic Calculator with three operation modes: evaluation of logical formulae; logical entailment and conversion of a formula to Disjunctive Normal Form (DNF) and Conjunctive Normal Form (CNF). It is worth noting there are no existing automated tools for these three computations integrated into one tool providing a graphical calculator format. Logic Calculator is available at https://sourceforge.net/p/logiccalculator

Diseño de software para validación dietética de menús nutritivos

Introduction: There is a number of software tools aimed at the validation of healthy menus, but their underlying model remains unknown and they are not very flexible to be modified. The goal of this project is to show a basis model, described in standard computer languages, flexible to be modified and also a related software tool for menu planning and validation. The software tool validates the Laws of Correct Nutrition, criteria described in most of the food guides are included in this model, yet allows to create constraint formulation without having knowledge in programming.Materials and methods: After the definition of the requirements via food guides analysis, we consult nutrition scientists from Universidad Juárez Autónoma de Tabasco. Then we design the software and implemented it. We capture the values included in the Mexican food tables. We finally validate and verify the model and some menus.Results: We develop an embedded system in which we perform the validation of 7 menus of people with different characteristics: 4 women and 3 men, ages ranging from 18 to 43 years, heights from 153 to 178 cm, weights from 48 to 78 kg, and budget from $60 to$200 Mexican pesos. These menus were validated by nutrition scientists.Conclusion: Menu planning for a nutritional-diet point of view is essential, as this is a heavy-resources-consuming process. To offer an adaptable software tool which performs menu validation automatically targets the solution of health problems related to feeding.Introducción: Aunque existe software que apoya la validación de menús nutritivos, el modelo que subyace es desconocido y poco flexible a modificaciones. El objetivo de este trabajo es mostrar un modelo base, descrito en lenguajes estándar, flexible a modificaciones para validar menús nutritivos, así como una herramienta que automatiza el proceso de generación de software a partir de modelos. Aunque el software generado valida las Leyes de la Correcta Alimentación, criterios descritos en la mayoría de las guías alimentarias son incluidos en este modelo, donde la formulación de restricciones puede ser modificada sin necesidad de tener conocimientos en programación.Material y método: Después definir los requerimientos al analizar varias guías alimentarias y consultar a nutriólogas de la Universidad Juárez Autónoma de Tabasco, se llevó a cabo el diseño del software e implementación, capturando los valores de las tablas de valor nutritivo de los alimentos de mayor consumo en México que sirvieron como base de datos. Al finalizar, se validaron y verificaron los menús.Resultados: Se generó un sistema embedido con el que se validaron 7 menús de personas con características variadas, 4 mujeres y 3 hombres, edades entre 18 y 43 años, tallas entre 153 y 178 cm, pesos entre 49 y 78 kg, y presupuestos entre $60 y$200 pesos. Todos los menús fueron también validados por nutriólogas y aceptados como adecuados.Conclusión: La elaboración de menús nutritivos para la intervención dietético-nutricional es esencial, este proceso consume demasiados recursos, así al ofrecer herramientas tecnológicas adaptables que automatizan la validación de esta tarea, se apoya en la solución de los problemas de salud directamente relacionados con la alimentación

Two-Swim Operators in the Modified Bacterial Foraging Algorithm for the Optimal Synthesis of Four-Bar Mechanisms

This paper presents two-swim operators to be added to the chemotaxis process of the modified bacterial foraging optimization algorithm to solve three instances of the synthesis of four-bar planar mechanisms. One swim favors exploration while the second one promotes fine movements in the neighborhood of each bacterium. The combined effect of the new operators looks to increase the production of better solutions during the search. As a consequence, the ability of the algorithm to escape from local optimum solutions is enhanced. The algorithm is tested through four experiments and its results are compared against two BFOA-based algorithms and also against a differential evolution algorithm designed for mechanical design problems. The overall results indicate that the proposed algorithm outperforms other BFOA-based approaches and finds highly competitive mechanisms, with a single set of parameter values and with less evaluations in the first synthesis problem, with respect to those mechanisms obtained by the differential evolution algorithm, which needed a parameter fine-tuning process for each optimization problem

The Chisholm paradox and the situation calculus

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