Search results for "Upper"
showing 10 items of 987 documents
Ontology Views for Ontology Change Management
2014
International audience; In the literature, ontology change management systems (OCMS) are direct implementation of the concept of “change management” stated by reference (Klein, 2004). Ontology change management combines ontol- ogy evolution and versioning features to manage ontol- ogy changes and their impacts. Since 2007, many works have combined ontology evolution and versioning into ontology change management systems (OCMS). The evolution subject has been massively studied in these works. They especially addressed the consistence issue for the application of changes on the ontology. These proposals constituted a consequent background for ontology change management but they did not take i…
Modeling Changes for SHOIN(D) Ontologies: An Exhaustive Structural Model
2013
Ontology development starts with a rigorous ontological analysis that provides a conceptualization of the domain to model agreed by the community. An ontology, specified in a formal language, approximates the intended models of this conceptualization. It needs then to be revised and refined until an ontological commitment is found. Also ulterior updates, responding to changes in the domain and/or the conceptualization, are expected to occur throughout the ontology life cycle. To handle a consistent application of changes, a couple of ontology evolution methodologies have been proposed. Maintaining the structural consistency is one of the ontology evolution criteria. It implies modeling chan…
Model Driven Specification of Ontology Translations
2008
The alignment of different ontologies requires the specification, representation and execution of translation rules. The rules need to integrate translations at the lexical, the syntactic and the semantic layer requiring semantic reasoning as well as low-level specification of ad-hoc conversions of data. Existing formalisms for representing translation rules cannot cover the representation needs of these three layers in one model. We propose a metamodel-based representation of ontology alignments that integrate semantic translations using description logics and lower level translation specifications into one model of representation for ontology alignments.
Data Mining of Specific-Domain Ontology Components
2008
This paper describes an approach for eliciting ontology components by using knowledge maps. The knowledge contained in a particular domain, any kind of text digital archive, is portrayed by assembling and displaying its ontology components.
Semi-automatic Derivation of Specific-Domain Ontologies for the Semantic Web
2006
This paper describes an approach for helping in the semi-automatic construction of specific-domain ontology components contained in a digital archive. This proposal for extracting knowledge from digital sources allows users to have a view of this knowledge and visualize specific-domain ontology components that with further processing can be shared with software agents by embedding it into digital archives themselves in the context of the Semantic Web. In particular, we deal with the issue of not constructing the ontology from scratch, our approach helps us to speed up the ontology creation process.
Computational methods for optimal shakedown design of FE structures
1998
The paper concerns the optimal shakedown design of structures discretized by elastic perfectly plastic finite elements. The design problem is formulated in four alternative versions, i.e. as the search for the minimum volume design whose shakedown limit load multiplier is assigned or as the search for the maximum shakedown limit load multiplier design whose volume is assigned; both problems are approached on the grounds of the shakedown lower bound and upper bound theorems. Correspondingly four computational methods, one for each original problem, are presented. These methods consist in solving iteratively new problems which are simpler than the original ones, but expressed in such a way th…
Optimal shakedown design of beam structures
1994
The optimal design of plane beam structures made of elastic perfectly plastic material is studied according to the shakedown criterion. The design problem is formulated by means of a statical approach on the grounds of the shakedown lower bound theorem, and by means of a kinematical approach on the grounds of the shakedown upper bound theorem. In both cases two different types of design problems are formulated: one searches for the minimum volume design whose shakedown limit load is assigned; the other searches for the design of the assigned volume whose shakedown limit load is maximum. The optimality conditions of the four problems above are found by the use of a variational approach; such…
Shakedown optimal design of reinforced concrete structures by evolution strategies
2000
Approaches the shakedown optimal design of reinforced concrete (RC) structures, subjected to variable and repeated external quasi‐static actions which may generate the well‐known shakedown or adaptation phenomenon, when constraints are imposed on deflection and/or deformation parameters, in order to simulate the limited flexural ductility of the material, in the presence of combined axial stress and bending. Within this context, the classical shakedown optimal design problem is revisited, using a weak upper bound theorem on the effective plastic deformations. For this problem a new computational algorithm, termed evolution strategy, is herein presented. This algorithm, derived from analogy …
On the Post-Elastic Behavior of LRPH Connections
2019
The paper concerns the study of the post-elastic behavior of a recently proposed innovative device, named Limited Resistance Rigid Perfectly Plastic Hinge (LRPH). In particular, LRPH is a steel device of finite length realizing a moment connection between beam elements of a steel frame; it is designed in order to possess two main and independent requirements: its bending moment resistance must be suitably lower than the one of the connected beam element and its overall bending stiffness must be equal to that of the connected beam element characterized by the same length. In order to make the proposed device reliable, LRPH must be capable of realizing a full plastic hinge for the assigned be…
Optimal Bounds on Plastic Deformations for Bodies Constituted of Temperature-Dependent Elastic Hardening Material
1997
Bounds are investigated on the plastic deformations in a continuous solid body produced during the transient phase by cyclic loading not exceeding the shakedown limit. The constitutive model employs internal variables to describe temperature-dependent elastic-plastic material response with hardening. A deformation bounding theorem is proved. Bounds turn out to depend on some fictitious self-stresses and mechanical internal variables evaluated in the whole structure. An optimization problem, aimed to make the bound most stringent, is formulated. The Euler-Lagrange equations related to this last problem are deduced and they show that the relevant optimal bound has a local character, i.e., it …