G.T. Nguyen and D. Rieu. Multiple object representations. In Proc. 20th ACM Computer Science Conference, pages 197-204, Kansas City (Mo), March 1992. ACM Press.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....common in engineering and scienti c applications because of the ability of object oriented models to capture facets of domain knowledge in a concise and intuitively understandable way. However, there are areas which can not yet suciently be modelled with standard object models [AWSL92, SLL92, NR92] One of these areas is the growing variety of variants existing for many engineering artifacts. This variety can be observed within the plastics industry as multi criteria selection tables, as one of a kind products in mechanical and chemical engineering, or as the thick sales catalogues for ....

....transitions. Nevertheless transitional restrictions seem to be more appropriate for modeling the life cycles of objects. In our application, where the user may want to randomly switch between di erent alternatives, they would either restrict him or would result in a tightly interconnected graph. NR92, NRE92] reason that standard object oriented models are inappropriate for several scienti c applications. Their modeling language SHOOD contains meta classes, multiple instantiation, and automatic classi cation. Name con icts in multiple instantiation are solved by specifying the origin class of ....

G.T. Nguyen and D. Rieu. Multiple object representations. In Proc. 20th ACM Computer Science Conference, pages 197-204, Kansas City (Mo), March 1992. ACM Press.

....models to describe the structure with semantic relationships of system entities. The object paradigm is enough rich and thus could provide such facilities. It has been widely used for its numerous advantages [Gar 90] We suggest to use the objectoriented model implemented in SHOOD system [Ngu 92] Ngu 91] Rie 91] to design the PIS core. Indeed, this model includes a variety of semantic relationships. The model is presented in section 3. decision makers FMS I1 I2 Production Information System e o x o e o x x o x o e e=event x=attribute o=operation Figure 1: The ....

....meta attribute. Obviously, generic triggers are useful for consistency of the PIS core. 6. IMPLEMENTATION ISSUES SHOOD is a knowledge based system which supports the object oriented data model above, extended with the composition and dependency relationships. SHOOD is based on three principles [Ngu 92] Ngu 91] every thing is an object, every object is an instance of another object, and any information concerning an object is stored in its attributes. An attribute class is an instance of the special meta class Met Attribute or one of its sub classes, which provides the facility for ....

Nguyen G.T, Rieu D., Multiple object representations. Proc 20th ACM Computer Science Corporation. Kansas City (USA) March 1992.

.... object oriented databases lack several capabilities needed in engineering databases where the domain is characterized by the following points: A low object class quotient, incomplete and inconsistent information, object evolution and different views on the model by different domain specialists [AWSL92, SLL92, NR92]. This paper focuses particularly on the problems we found using object oriented modeling for conceptual abstractions of mathematical simulation models in chemical engineering. These abstractions model a chemical process on the level of individual chemical phases 1 and bridge the gap between ....

....Nevertheless transitional restrictions seem to be more appropriate for modeling the life cycles of objects. In our application, where the user may want to randomly switch between different alternatives, they would either restrict him or would result in a tightly interconnected graph. [NR92, NRE92] reason that standard object oriented models are inappropriate for several scientific applications. Their modeling language SHOOD contains meta classes, multiple instantiation, and automatic classification. Name conflicts in multiple instantiation are solved by specifying the origin class of the ....

G.T. Nguyen and D. Rieu. Multiple object representations. In Proc. 20th ACM Computer Science Conference, pages 197--204, Kansas City (Mo), March 1992. ACM Press.

....model. Using an odmg compliant database, an impedance mismatch appears since object types used in the application dioeer from the one used in the database. Hence the user would have to implement a mapping engine between the two representations. Another problem raises with systems like Shood [NR92, RNC 91] that allow multiple instantiation. Using an odmg database, a dioeerence between application s class tree and database one may occur. As a matter of fact, the database s class tree would include classes with no equivalent in the application one. These classes only justi cation is to ....

G. T. Nguyen and D. Rieu. Multiple object representations. ACM Computer Science Conference, 1992.

....to simplify complexity and, on the other one, semantic relationships permit expression of generic triggers and hence efficient consistency control among information objects. Indeed, the SHOOD concepts applied here for data knowledge structuring have already been used to CAD CAM systems design [10, 11]; and Petri net has been employed to describe an interaction scenario among MRP (Manufacturing Requirement Planning) CAM and CAD packages [4] 2 System Architecture and Global Modelling Methodology Petri nets are powerful tools for modelling, simulation, validation and control of discrete event ....

....is executed on is composed of need is assembled according to is composed of is manufactured according to is manufactured according to is elaborated on is composed of require a level of property of provisioned according to Fig. 1. PIS elements The latter presents SHOOD, a Knowledge Based System [10, 11, 12] which supports an Object oriented Data Model extended with the composition and dependency relationships. It eliminates the shortcomings while retaining the advantages of the existing systems which seem more limited models [8] For all these reasons, we shall use SHOOD concepts to specify the ....

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Nguyen G.T, Rieu D., Multiple object representations. Proc 20th ACM Computer Science Corporation. Kansas City (USA) March 1992.

....etc. It also overcomes their most stringent assumptions. For example, object instances may belong simultaneously to several classes, providing a straightforward implementation of multiple points of view (Nguyen, 1990) Objects instances may also be partially incomplete and inconsistent (Nguyen, 1992). Hence, an instance may not necessarily be an exact representative of a specific class. These last two features depart from fundamental assumptions in existing object oriented models. They are indeed necessary in design applications because the definition of an adequate object structure, even ....

....on existing notions e.g specialization, aggregates and multiple instantiation. There is no need for specific operators to define and manipulate the representations. This greatly simplifies the concepts and mechanisms involved in the implementation of the data model. This approach is used for SHOOD (Nguyen, 1992; Rieu, 1992). It uses the notion of multiple instantiation, by which an instance is allowed to belong simultaneously to several classes. They are not necessarily related by a specialization relationship. An instance can therefore belong simultaneously to the Aircraft class and to the Museum collection class ....

Nguyen G.T, Rieu D. 1992. Multiple object representations. Proc. 20th ACM Computer Science Conference. Kansas City (Mo).

....inheritance, etc. It also overcomes their most stringent assumptions. For example, object instances may belong simultaneously to several classes, providing a straightforward implementation of multiple points of view [21] Objects instances may also be partially incomplete and inconsistent [23]. Therefore, instances are not necessarily precise representatives of specific classes. These last two features depart from fundamental assumptions in existing object oriented models. They are necessary in design applications because the definition of an adequate object structure, even prior to ....

....existing notions, e.g. specialization, aggregates and multiple instantiation. There is no need for specific operators to define and manipulate the representations. This greatly simplifies the concepts and mechanisms involved in the implementation of the data model. This approach is used for SHOOD [23, 28]. It uses the notion of multiple instantiation, by which an instance is allowed to belong simultaneously to several classes. They are not necessarily related by a specialization relationship. An instance can therefore belong simultaneously to the Aircraft class and to the Museum collection class ....

Nguyen G.T, Rieu D. Multiple object representations. Proc. 20th ACM Computer Science Conference. Kansas City (Mo). 1992.

....The project SHOOD is developed at INRIA, Rh ne Alpes Research Unit, in Grenoble (France) The goal is to provide tools and methods for the integration of engineering design systems. This is developed in three work packages: the definition of a generic product model, based on the object paradigm [NGU92a], the formal specification of a reactive design model, which is the main scope of this paper, the development of an integration platform, that supports concurrent engineering of the design products (Figure 1) Figure 2. SHOOD s user interface. June 15, 1995 4 Nguyen G.T The generic product ....

....The automaton monitors in real time the impact of the designers modifications on the objects. The concurrent engineering platform is therefore a true reactive system, which tracks closely the design process of complex objects. The objects are modeled in SHOOD by their different representations [NGU92a]. They are also characterized by their current state (public, private or transient) and their various components. The representations include specific constraints, called intra representation constraints, that model design knowledge, particular to the various skills required in the projects. They ....

NGUYEN G.T, et al. Multiple object representations. Proc. 20th ACM Computer Science Conference. May 1992. Kansas City (USA).

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