scholarly journals Decidable Reasoning in Terminological Knowledge Representation Systems

1993 ◽  
Vol 1 ◽  
pp. 109-138 ◽  
Author(s):  
M. Buchheit ◽  
F. M. Donini ◽  
A. Schaerf
Keyword(s):  
Knowledge Representation ◽  
Knowledge Bases ◽  
Point Of View ◽  
Theoretical Point ◽  
General Technique ◽  
Practical Applications ◽  
Constraint Systems ◽  
Representation Systems ◽  
Concept Languages ◽  
Knowledge Representation Systems

Terminological knowledge representation systems (TKRSs) are tools for designing and using knowledge bases that make use of terminological languages (or concept languages). We analyze from a theoretical point of view a TKRS whose capabilities go beyond the ones of presently available TKRSs. The new features studied, often required in practical applications, can be summarized in three main points. First, we consider a highly expressive terminological language, called ALCNR, including general complements of concepts, number restrictions and role conjunction. Second, we allow to express inclusion statements between general concepts, and terminological cycles as a particular case. Third, we prove the decidability of a number of desirable TKRS-deduction services (like satisfiability, subsumption and instance checking) through a sound, complete and terminating calculus for reasoning in ALCNR-knowledge bases. Our calculus extends the general technique of constraint systems. As a byproduct of the proof, we get also the result that inclusion statements in ALCNR can be simulated by terminological cycles, if descriptive semantics is adopted.

Knowledge Extraction from Domain-Specific Documents

2017 ◽  
pp. 106-123
Author(s):  
Ram Kumar ◽  
Shailesh Jaloree ◽  
R. S. Thakur
Keyword(s):  
Knowledge Representation ◽  
Knowledge Base ◽  
Knowledge Bases ◽  
Domain Ontology ◽  
Knowledge Based Systems ◽  
Domain Specific ◽  
Knowledge Based ◽  
Representation Systems ◽  
Terminological Confusion ◽  
Knowledge Representation Systems

Knowledge-based systems have become widespread in modern years. Knowledge-base developers need to be able to share and reuse knowledge bases that they build. As a result, interoperability among different knowledge-representation systems is essential. Domain ontology seeks to reduce conceptual and terminological confusion among users who need to share various kind of information. This paper shows how these structures make it possible to bridge the gap between standard objects and Knowledge-based Systems.

Study of the properties of materials under complicated conditions of low cycle deformation

2021 ◽  
Vol 87 (7) ◽  
pp. 49-58
Author(s):  
N. A. Makhutov ◽  
М. M. Gadenin ◽  
О. F. Cherniavsky ◽  
A. О. Cherniavsky
Keyword(s):  
Initial Data ◽  
Equations Of State ◽  
Complex Loading ◽  
Time Factors ◽  
Point Of View ◽  
Theoretical Point ◽  
Operational Parameters ◽  
Practical Applications ◽  
Wide Range ◽  
Deformation Diagrams

Operational integrity of structures under complex combined modes of a loading depends on a significant number of combinations of operational parameters of thermomechanical impacts in part of loads, temperatures, duration, number of cycles, and deformation rates. The main laws governing the deformation of structural materials under complex loading are determined in conditions of combined standard, unified and special tests in laboratories. Using representative substantiations of physical and mechanical models for deformation diagrams in a wide range of loading conditions, taking into account the different scales of models, the structure of materials and the responsibility of structures, a stepwise consideration of the corresponding types of deformation is proposed: elastic, sign-variable flow, progressing accumulation of strains and their combination. At the same time, calculations of the structures can be carried out in the form of a hierarchical system in which each next level specifies the boundaries of permissible impacts towards expansion of the range of acting loadings, temperatures, rates and modes of deformation, which entails an increase in the bulk of the required initial data and complicates the calculations. The proposed methods of schematization of the physicomechanical properties and types of the equations of state for description of the deformation curves take into account the requirements of compactness of the initial data and the need of using both standard and unified methods for determining the characteristics of cyclic inelastic deformation and special methods as well. To describe the kinetics of deformation diagrams under aforementioned conditions both from the theoretical point of view and from the point of view of practical applications, power equations appeared most suitable; to reflect the role of the temperature factor exponential dependences should be used; whereas power dependences are useful to take into account time factors, strain rate, and conditions of two-frequency loading. The refined calculations at the higher and more complicated steps of the considered hierarchy providing the maximum possible use of the deformation and strength reserves of the materials and structures are to be based on the kinetic laws describing processes of low cycle deformation under complex modes of loading.

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