230,126 research outputs found
The Space Object Ontology
Achieving space domain awareness requires the
identification, characterization, and tracking of space objects.
Storing and leveraging associated space object data for purposes
such as hostile threat assessment, object identification, and
collision prediction and avoidance present further challenges.
Space objects are characterized according to a variety of
parameters including their identifiers, design specifications,
components, subsystems, capabilities, vulnerabilities, origins,
missions, orbital elements, patterns of life, processes, operational
statuses, and associated persons, organizations, or nations. The
Space Object Ontology provides a consensus-based realist
framework for formulating such characterizations in a
computable fashion. Space object data are aligned with classes
and relations in the Space Object Ontology and stored in a
dynamically updated Resource Description Framework triple
store, which can be queried to support space domain awareness
and the needs of spacecraft operators. This paper presents the
core of the Space Object Ontology, discusses its advantages over
other approaches to space object classification, and demonstrates
its ability to combine diverse sets of data from multiple sources
within an expandable framework. Finally, we show how the
ontology provides benefits for enhancing and maintaining longterm
space domain awareness
An Object-Oriented Approach to Knowledge Representation in a Biomedical Domain
An object-oriented approach has been applied to the different stages involved in developing a knowledge base about insulin metabolism. At an early stage the separation of terminological and assertional knowledge was made. The terminological component was developed by medical experts and represented in CORE. An object-oriented knowledge acquisition process was applied to the assertional knowledge. A frame description is proposed which includes features like states and events, inheritance and collaboration. States and events are formalized with qualitative calculus. The terminological knowledge was very useful in the development of the assertional component. It assisteed in understanding the problem domain, and in the implementation stage, it assisted in building good inheritance hierarchies
Boolean Coverings of Quantum Observable Structure: A Setting for an Abstract Differential Geometric Mechanism
We develop the idea of employing localization systems of Boolean coverings,
associated with measurement situations, in order to comprehend structures of
Quantum Observables. In this manner, Boolean domain observables constitute
structure sheaves of coordinatization coefficients in the attempt to probe the
Quantum world. Interpretational aspects of the proposed scheme are discussed
with respect to a functorial formulation of information exchange, as well as,
quantum logical considerations. Finally, the sheaf theoretical construction
suggests an opearationally intuitive method to develop differential geometric
concepts in the quantum regime.Comment: 25 pages, Late
Embedding object-oriented design in system engineering
The Unified Modeling Language (UML) is a collection of techniques intended to document design decisions about software. This contrasts with systems engineering approaches such as for exampleStatemate and the Yourdon Systems Method (YSM), in which the design of an entire system consisting of software and hardware can be documented. The difference between the system- and the software level is reflected in differences between execution semantics as well as in methodology. In this paper, I show how the UML can be used as a system-level design technique. I give a conceptual framework for engineering design that accommodates the system- as well as the software level and show how techniques from the UML and YSM can be classified within this framework, and how this allows a coherent use of these techniques in a system engineering approach. These ideas are illustrated by a case study in which software for a compact dynamic bus station is designed. Finally, I discuss the consequences of this approach for a semantics of UML constructs that would be appropriate for system-level design
Requirements analysis of the VoD application using the tools in TRADE
This report contains a specification of requirements for a video-on-demand (VoD) application developed at Belgacom, used as a trial application in the 2RARE project. The specification contains three parts: an informal specification in natural language; a semiformal specification consisting of a number of diagrams intended to illustrate the informal specification; and a formal specification that makes the requiremants on the desired software system precise. The informal specification is structured in such a way that it resembles official specification documents conforming to standards such as that of IEEE or ESA. The semiformal specification uses some of the tools in from a requirements engineering toolkit called TRADE (Toolkit for Requirements And Design Engineering). The purpose of TRADE is to combine the best ideas in current structured and object-oriented analysis and design methods within a traditional systems engineering framework. In the case of the VoD system, the systems engineering framework is useful because it provides techniques for allocation and flowdown of system functions to components. TRADE consists of semiformal techniques taken from structured and object-oriented analysis as well as a formal specification langyage, which provides constructs that correspond to the semiformal constructs. The formal specification used in TRADE is LCM (Language for Conceptual Modeling), which is a syntactically sugared version of order-sorted dynamic logic with equality. The purpose of this report is to illustrate and validate the TRADE/LCM approach in the specification of distributed, communication-intensive systems
Reference fiction, and omission
In this paper, I argue that sentences that contain āomissionā tokens that appear to function as singular terms are meaningful while maintaining the view that omissions are nothing at all or mere absences. I take omissions to be fictional entities and claim that the way in which sentences about fictional characters are true parallels the way in which sentences about omissions are true. I develop a pragmatic account of fictional reference and argue that my fictionalist account of omissions implies a plausible account of the metaphysics of omissions
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