Logical operators for ontological modeling

We show that logic has more to offer to ontologists than standard first order and modal operators. We first describe some operators of linear logic which we believe are particularly suitable for ontological modeling, and suggest how to interpret them within an ontological framework. After showing how they can coexist with those of classical logic, we analyze three notions of artifact from the literature to conclude that these linear operators allow for reducing the ontological commitment needed for their formalization, and even simplify their logical formulation

Spheres, cubes and simple

In 1929 Tarski showed how to construct points in a region-based first-order logic for space representation. The resulting system, called the geometry of solids, is a cornerstone for region-based geometry and for the comparison of point-based and region-based geometries. We expand this study of the construction of points in region-based systems using different primitives, namely hyper-cubes and regular simplexes, and show that these primitives lead to equivalent systems in dimension n ≥ 2. The result is achieved by adopting a single set of definitions that works for both these classes of figures. The analysis of our logics shows that Tarski’s choice to take sphere as the geometrical primitive might be intuitively justified but is not optimal from a technical viewpoint

Raising Household Leverage: Evidence from Co-Financed Mortgages

This article studies the impact on mortgage origination conditions and performance of a product that aims at raising household leverage: bank mortgages co-financed with a housing provident fund (HPF), a compulsory saving scheme for all private sector workers in Mexico. Relative to traditional bank mortgages, our estimates show that down payment of the co-financed declines substantially, by 7.6 percentage points, whereas purchased properties are not more expensive. Despite their higher leverage, co-financed bank mortgages do not exhibit higher default rates---their lower liquidity needs to cover upfront costs and monthly payments reduce credit risk. We also find distributional effects: The scheme alleviates borrowing constraints more at lower incomes, especially when banks are smaller. Larger banks, with a greater share of low-income borrowers, use co-financing to reduce the amount lent to those segments. Thus, when the HPF's lending conditions become relatively less generous at lower incomes, we find that larger banks neutralize the substitution between traditional and co-financed mortgages that is found on smaller banks' portfolios

Events and Activities: Is there an Ontology behind BPMN?

In the context of business process modelling, the Business Process Model and Notation (BPMN) is a de-facto standard with more than 70 commercial tools that currently support its use. Amongst its main modelling constructs, BPMN includes activities and events. However, the focus of the standard is on providing an intuitive graphical language, rather than formal semantics specifications. This results in semantic ambiguities regarding the interpretation of its modelling constructs. We investigate whether the main building blocks of BPMN commit to an ontological theory of the domain entities at hand, eventually clarifying this commitment by the approach of ontological analysis

Urban Artefacts and Their Social Roles: Towards an Ontology of Social Practices

Cities can be seen as systems of urban artefacts interacting with human activities. Since cities in this sense need to be organized and coordinated, convergences and divergences between the "planned" and the "lived" city have always been of paramount interest in urban planning. The increasing amount of geo big data and the growing impact of Internet of Things (IoT) in contemporary smart city is pushing toward a re-conceptualization of urban systems taking into consideration the complexity of human behaviors. This work contributes to this view by proposing an ontological analysis of urban artefacts and their roles, focusing in particular on the difference between social roles and functional roles through the prism of social practices

OCRA – An ontology for collaborative robotics and adaptation

Industrial collaborative robots will be used in unstructured scenarios and a large variety of tasks in the near future. These robots shall collaborate with humans, who will add uncertainty and safety constraints to the execution of industrial robotic tasks. Hence, trustworthy collaborative robots must be able to reason about their collaboration’s requirements (e.g., safety), as well as the adaptation of their plans due to unexpected situations. A common approach to reasoning is to represent the knowledge of interest using logic-based formalisms, such as ontologies. However, there is not an established ontology defining notions such as collaboration or adaptation yet. In this article, we propose an Ontology for Collaborative Robotics and Adaptation (OCRA), which is built around two main notions: collaboration, and plan adaptation. OCRA ensures a reliable human-robot collaboration, since robots can formalize, and reason about their plan adaptations and collaborations in unstructured collaborative robotic scenarios. Furthermore, our ontology enhances the reusability of the domain’s terminology, allowing robots to represent their knowledge about different collaborative and adaptive situations. We validate our formal model, first, by demonstrating that a robot may answer a set of competency questions using OCRA. Second, by studying the formalization’s performance in limit cases that include instances with incongruent and incomplete axioms. For both validations, the example use case consists in a human and a robot collaborating on the filling of a tray.Peer ReviewedPostprint (published version

Persistent high plasma levels of sCD163 and sCD14 in adult patients with measles virus infection

Background and aims: Measles is an infectious disease that represents a serious public health problem worldwide, being associated with increased susceptibility to secondary infections, especially in the respiratory and gastrointestinal tracts. The aim of this study was to evaluate sCD163 and sCD14 levels in measles virus (MV) infected patients, as markers of immune activation, in order to better understand their role in the pathogenesis of the disease. TNF-α plasma levels were also evaluated. Methods: sCD163, sCD14 and TNF-α were measured by ELISA in plasma samples of 27 MV infected patients and 27 healthy donors (HD) included as controls. Results: At the time of hospital admission, sCD163 and sCD14 levels were significantly higher in MV infected patients than in HD, while a decrease in TNF-α levels were found even if without statistical significance. sCD163 and sCD14 levels were significantly decreased after two months from acute infection compared to hospital admission although they remained significantly higher compared to HD. TNF-α levels increased significantly during the follow-up period. Considering clinical parameters, sCD163 levels positively correlated with aspartate aminotransferase, white blood cell count and neutrophils rate, while negatively correlated with the lymphocyte percentage. sCD14 levels positively correlated with the neutrophil and lymphocyte percentages. Conclusions. These results indicate that, despite the resolution of symptoms, an important macrophage/ monocyte activation persists in measles patients, even after two months from infection

FailRecOnt - An ontology-based framework for failure interpretation and recovery in planning and execution

Autonomous mobile robot manipulators have the potential to act as robot helpers at home to improve quality of life for various user populations, such as elderly or handicapped people, or to act as robot co-workers on factory floors, helping in assembly applications where collaborating with other operators may be required. However, robotic systems do not show robust performance when placed in environments that are not tightly controlled. An important cause of this is that failure handling often consists of scripted responses to foreseen complications, which leaves the robot vulnerable to new situations and ill-equipped to reason about failure and recovery strategies. Instead of libraries of hard-coded reactions that are expensive to develop and maintain, more sophisticated reasoning mechanisms are needed to handle failure. This requires an ontological characterization of what failure is, what concepts are useful to formulate causal explanations of failure, and integration with knowledge of available resources including the capabilities of the robot as well as those of other potential cooperative agents in the environment, e.g. a human user. We propose the FailRecOnt framework as a step in this direction. We have integrated an ontology for failure interpretation and recovery with a contingency-based task and motion planning framework such that a robot can deal with uncertainty, recover from failures, and deal with human-robot interactions. A motivating example has been introduced to justify this proposal. The proposal has been tested with a challenging scenarioPeer ReviewedPostprint (published version

Features and Components in Product Models

Product structures are represented in engineering models by depicting and linking components, features and assemblies. Their understanding requires knowledge of both design and manufacturing practices, and yet further contextual reasoning is needed to read them correctly. Since these representations are essen- tial to the engineering activities, the lack of a clear and explicit semantics of these models hampers the use of information systems for their assessment and exploita- tion. We study this problem by identifying different interpretations of structure rep- resentations, and then discuss the formal properties that a suitable language needs for representing components, features and combinations of these. We show that the representation of components and features require a non-standard mereology