Minmax regret combinatorial optimization problems: an Algorithmic Perspective

Candia-Vejar, A (reprint author), Univ Talca, Modeling & Ind Management Dept, Curico, Chile.Uncertainty in optimization is not a new ingredient. Diverse models considering uncertainty have been developed over the last 40 years. In our paper we essentially discuss a particular uncertainty model associated with combinatorial optimization problems, developed in the 90's and broadly studied in the past years. This approach named minmax regret (in particular our emphasis is on the robust deviation criteria) is different from the classical approach for handling uncertainty, stochastic approach, where uncertainty is modeled by assumed probability distributions over the space of all possible scenarios and the objective is to find a solution with good probabilistic performance. In the minmax regret (MMR) approach, the set of all possible scenarios is described deterministically, and the search is for a solution that performs reasonably well for all scenarios, i.e., that has the best worst-case performance. In this paper we discuss the computational complexity of some classic combinatorial optimization problems using MMR. approach, analyze the design of several algorithms for these problems, suggest the study of some specific research problems in this attractive area, and also discuss some applications using this model

Methodological principles to create a metadata extension to the Darwin Core standard for agrobiodiversity data.

Abstract. This paper aims to propose principles for creating a metadata extension to the Darwin Core standard that addresses the agrobiodiversity data, with a scope on ecological interactions. These principles have been compiled from the scientific literature, giving special attention to recommendations of the DCMI Abstract Model, which outlines the principles for creating metadata. The DCMI Abstract Model governs the creation of the Dublin Core metadata standard upon which Darwin Core is based. The requirements of ISO/IEC 11179-4/2004 standard for the definition of metadata were also taken into consideration. A prototype of a metadata record for the field of ecological interactions, which is the scope of this research within agrobiodiversity, was created to demonstrate the format that metadata will have when the extension is finished. This research an effort to propose more effective tools for agrobiodiversity data management, but it is necessary to mature and deepen the discussions around the conceptual aspects of the ecological interactions in agrobiodiversity and the relationship of the new metadata extension with the vocabulary of the Darwin Core, as well a robust methodology to create DwC extensions is still pending of being developed.Artigo e020015

Refinamento de relações em tesauros: reengenharia do Thesagro.

Apresenta resultados de pesquisa que teve como objetivo estudar um modelo de reengenharia de tesauros tradicionais para transformar a sua estrutura em um sistema de conceitos formado por relações semanticamente mais refinadas. Como fundamento teórico foram utilizados conteúdos sobre sistemas de organização do conhecimento (SOCs) e seus relacionamentos semânticos em tesauros, o conceito e a definição que o delimita, a teoria da Valência Verbal e dos papéis Qualia. A modelagem foi aplicada no tesauro brasileiro THESAGRO, do domínio da Agricultura, tendo como recorte temático a subárea da Intensificação Agropecuária. A metodologia foi aplicada a partir do modelo proposto em dois artigos: Soergel et al. (2004) e Lauser et al. (2006). O modelo é composto por três etapas e sua aplicação consistiu na explicitação formal das relações de equivalência e das relações conceituais na estrutura do THESAGRO. Na implantação do modelo foram utilizados dois softwares: (1) o E-Termos, que foi o sistema colaborativo utilizado na gestão terminológica, e (2) o Extrator de Termos, que permite a comparação automática da terminologia de diferentes tesauros. Os resultados demonstraram que o modelo aplicado permitiu o refinamento semântico da estrutura conceitual do THESAGRO, demonstrando a viabilidade de seu uso na conversão de um tesauro tradicional em uma estrutura mais formalizada. Concluiu-se que esse refinamento tem papel basilar na organização do conhecimento, podendo facilitar a sua utilização pelo utilizador final, assim como é um elemento importante para obter a interoperabilidade entre os distintos tesauros e entre diferentes sistemas de recuperação de informação (SRI).Enancib 2015. Refining Thesaurus relationships: reengineering of Thesagro

Production of subject-verb agreement, tense, mood, and negation in Italian agrammatic aphasia

Impaired (morpho)syntactic production is the hallmark of agrammatic aphasia. Several hypotheses have been proposed to account for agrammatic production, which often make different predictions. The Distributed Morphology Hypothesis (DMH) (Wang et al., 2014) posits that categories involving inflectional alternations are impaired in agrammatism. The Tense Underspecification Hypothesis (TUH) (Wenzlaff & Clahsen, 2004, 2005) states that what is impaired (\u201cunderspecified\u201d) is tense; subject-verb agreement and mood are well-preserved. The Interpretable Features\u2019 Impairment Hypothesis (IFIH) (Fyndanis et al., 2012) predicts categories involving integration processes (e.g., tense, mood, negation) to be more impaired than categories that do not involve integration processes (e.g., agreement). The Tree Pruning Hypothesis (TPH) (Friedmann & Grodzinsky, 1997) states that the syntactic tree is pruned at a specific node, usually tense, with all nodes/categories above the pruning site deleted/inaccessible and all nodes below intact. To reliably test these accounts, one should test agrammatic speakers on a wide range of (morpho)syntactic phenomena/categories. In this study, we investigate the ability of Italian-speaking agrammatic individuals to produce subject-verb agreement, tense, mood, and sentential negation. A sentence completion task (SCT) tapping agreement and tense, a SCT assessing mood, and a constituent ordering task tapping negation were administered to eight native speakers of Italian with chronic agrammatic aphasia and eight controls. Results are presented in Table 1. The control group performed better than the aphasic group on all four conditions. Both groups showed similar patterns of performance, with better performance on agreement and tense than on mood. Negation was better preserved than agreement, tense, and mood in the aphasic group, but in the control group negation was not different from any other category. At the individual level, five agrammatic participants exhibited the same pattern of performance (agreement/tense/negation>mood). At the group level, the results of the agrammatic participants are not consistent with any of the hypotheses discussed here. Contrary to the TUH, participants performed better on tense than on mood. The DMH cannot explain the observed, selective impairment of categories involving inflectional alternations (tense/agreement>mood). Results do not support the TPH, as the higher the category in the syntactic hierarchy (Neg>T(future/past)>M) (Cinque, 1999; Zanuttini, 2001), the better the performance of agrammatic participants. Lastly, results are at odds with the IFIH, because negation (+integration processes) is better preserved than agreement (-integration processes). Analogous results are observed at the individual level. None of the available hypotheses can account for the patterns of performance of all the agrammatic participants. Their results, together with the production results of other agrammatic speakers in the literature, show that all possible patterns can be observed in agrammatism, and that a unitary account of the disorder is unlikely to succeed. We suggest that subject-specific characteristics (e.g., site/type/volume of brain damage, type/severity of language impairment, education, age) and language-specific properties of functional categories (e.g., syntactic hierarchy, interpretability/involvement of integration processes, frequency) may interact in determining the way in which (morpho)syntactic impairments manifest themselves across agrammatic speakers and languages