Search results for "Mathematical"

The directed profitable rural postman problem with incompatibility constraints

2017

[EN] In this paper, we study a variant of the directed rural postman problem (RPP) where profits are asso- ciated with arcs to be served, and incompatibility constraints may exist between nodes and profitable arcs leaving them. If convenient, some of the incompatibilities can be removed provided that penalties are paid. The problem looks for a tour starting and ending at the depot that maximizes the difference between collected profits and total cost as sum of traveling costs and paid penalties, while satisfying remaining incompatibilities. The problem finds application in the domain of road transportation service, and in particular in the context of horizontal collaboration among carriers …

The periodic rural postman problem with irregular services on mixed graphs

2019

Abstract In this paper, we deal with an extension of the rural postman problem in which some links of a mixed graph must be traversed a given number of times over a time horizon. These links represent entities that must be serviced a specified number of times in some subsets of days (or periods) of the time horizon. The aim is to design a set of minimum-cost tours, one for each day/period of the time horizon, that satisfy the service requirements. We refer to this problem as the periodic rural postman problem with irregular services (PRPP–IS). Some practical applications of the problem can be found in road maintenance operations and road network surveillance, for example. In order to solve …

Mark Baker (2015),Case: Its principles and parameters

2018

Semi-automated annotation of page-based documents within the Genre and Multimodality framework

2016

This paper describes ongoing work on a tool developed for annotating document images for their multimodal features and compiling this information into a corpus. The tool leverages open source computer vision and natural language processing libraries to describe the content and structure of multimodal documents and to generate multiple layers of XML annotation. The paper introduces the annotation schema, describes the document processing pipeline and concludes with a brief description of future work.

Use of contrastive syllabic information in L1-L2map for Spanish pronunciation teaching

2018

En la adquisición del sistema fónico de una segunda lengua (L2) al aprendiz no le basta con familiarizarse con los nuevos sonidos nuevos de la L2, sino que debe interiorizar las pautas distribucionales de los segmentos y las restricciones silábicas propias de la L2. El objetivo de este trabajo es, por un lado, reflexionar sobre los factores lingüísticos y contrastivos que pueden influir en la adquisición de las restricciones silábicas del español como lengua extranjera y, por otro lado, presentar las nuevas funciones de la base de datos multilingüe L1-L2map que permiten, precisamente, realizar análisis contrastivos de la estructura silábica de una lengua nativa (L1) y una L2. A lo largo del…

Formulating 'principles of procedure' for the foreign language classroom: A framework for process model language curricula

2015

This article aims to apply Stenhouse's process model of curriculum to foreign language (FL) education, a model which is characterized by enacting principles of procedure which are specific to the discipline which the school subject belongs to. Rather than to replace or dissolve current approaches to FL teaching and curriculum development, this article seeks to improve and enrich communicative and task-based orientations with an additional criterion for assessing the educational worth of the tasks through which these orientations are developed. Unlike the objectives and competences models, principles of procedure provide an intrinsic justification of school curriculum by enacting the epistem…

Talis pater, talis filius: the role of discursive strategies, thematic narratives and ideology in Cosa Nostra

2018

The discursive analysis of criminal organizations’ family dynamics and ideological devices may provide important insights into the inner functioning of these groups. In this article, we describe and analyze a specific set of discursive strategies and the thematic narratives emerging from a TV interview with Giuseppe Riina, a member of Cosa Nostra and the son of one of the most important mafia bosses. Our analyses demonstrate the existence of recurring ideological devices such as reductionism, amoralism, familism, verticalism, normalism, victimism and religious relativism. The results are discussed in light of previous research that examines how discursive strategies and narratives may repre…

The usefulness of a mathematical model of exposure for environmental risk assessment

2011

We respond to the Comment of Lang et al . [[1][1]] regarding our mathematical model [[2][2]] of exposure of non-target Lepidoptera to Bt -maize pollen expressing Cry1Ab within Europe. Lang et al . remark on the degree to which the model was subject to uncertainty. Perry et al . [[2][2]] did indeed

A mathematical model of exposure of nontarget Lepidoptera to Bt-maize pollen expressing Cry1Ab within Europe

2010

Genetically modified (GM) maize MON810 expresses a Cry1Ab insecticidal protein, derived from Bacillus thuringiensis ( Bt ), toxic to lepidopteran target pests such as Ostrinia nubilalis . An environmental risk to non-target Lepidoptera from this GM crop is exposure to harmful amounts of Bt -containing pollen deposited on host plants in or near MON810 fields. An 11-parameter mathematical model analysed exposure of larvae of three non-target species: the butterflies Inachis io (L.), Vanessa atalanta (L.) and moth Plutella xylostella (L.), in 11 representative maize cultivation regions in four European countries. A mortality–dose relationship was integrated with a dose–distance relationship t…

Theoretical conditions for the coexistence of viral strains with differences in phenotypic traits : A bifurcation analysis

2019

We investigate the dynamics of a wild-type viral strain which generates mutant strains differing in phenotypic properties for infectivity, virulence and mutation rates. We study, by means of a mathematical model and bifurcation analysis, conditions under which the wild-type and mutant viruses, which compete for the same host cells, can coexist. The coexistence conditions are formulated in terms of the basic reproductive numbers of the strains, a maximum value of the mutation rate and the virulence of the pathogens. The analysis reveals that parameter space can be divided into five regions, each with distinct dynamics, that are organized around degenerate Bogdanov–Takens and zero-Hopf bifurc…