idef3_kbsi_report (1013870), страница 36
Текст из файла (страница 36)
It ishelpful to partition the schematic into understandable pieces. Although there is no “right”or “wrong” way of partitioning a schematic, a partitioning procedure based on thestructure of the schematic is often helpful. This approach will be illustrated using anexample Process Schematic. Following this example, an illustration of the same conceptsapplied to an Object Schematic is presented.The example IDEF3 Process Schematic shown in Figure 6-1 can be partitioned alongstructural lines as indicated in Figure 6-2.180&&J2J3OOJ1J4Figure 6-1Example IDEF3 Process SchematicBb4b1b2A&&J2J3Db3OOCJ1J4Figure 6-2Example Partitioning of Figure 6-1In Figure 6-2, the schematic has been partitioned into four major groupings: A, B, C,and D.
These groupings represent four process paths. An examination of these groupingsreveals that B can be further partitioned into subgroupings b1, b2, b3, and b4. Once thedesired groupings and subgroupings have been established, analysis of the individualstructures can begin.Numbering the groupings 1 through 8 (see Figure 6-3) and starting with grouping 1 onthe far left of the description, readers typically proceed from left to right and perform thefollowing activities:1811.Read the UOBs and their elaborations.2.Examine links and note the information found in the linkelaborations.3.Consider all referents and notes within the bounds of the selectedgrouping.65231&&J2J384OO7J4J1Figure 6-3Analyzing the GroupingsAfter understanding grouping 1, the reader will study either grouping 6 or grouping 7.Note that junction J1 is not immediately considered at this stage.
Starting with grouping6, each of the subgroupings 2 and 5 (themselves groupings) will be analyzed. Theanalysis of grouping 2 means that one UOB and its elaboration must be studied.Grouping 5 is a complex grouping which will be first subdivided into groupings 3 and 4.After completing the study of groupings 3 and 4, grouping 6 is analyzed in its entirety.This process involves understanding the logic of the grouping that includes the J2 fan-outjunction from grouping 2 to groupings 3 and 4. To understand junction J2, readersexamine the two paths leading from it and note the conditions of flow to these paths. Ingeneral, the logic of a junction is analyzed by following all of the paths leading in or outof it, and noting the conditions under which each path will be selected. The study ofgrouping 5 is completed by analyzing the logic of the fan-in junction J3.The reader would then attempt to understand grouping 7.
After completing theanalysis of grouping 7, reading of the description will continue with the analysis of fanout junction J1. The reader would perform a mental walkthrough of the process startingfrom grouping 1, noting the conditions under which the flow would branch at the junction182and the conditions governing each fan-out path.
In this case, the reader would notice thepresence of a constrained precedence link, indicating a need to closely examine theassociated precedence link elaboration form.The next descriptive element of the diagram to be analyzed is the fan-in junction J4that enables merging of the process paths emerging from groupings 6 and 7. Readerswould do a mental walkthrough that involved analyzing the logic of junction J4, notingthe conditions under which the two process paths converge.Finally, grouping 8 is analyzed by reading UOB 8 and its elaboration, and consideringany referent that may be attached to it.
After this, readers may want to do a completemental walkthrough of the entire diagram. This will involve starting again at the left endof the schematic and continuing through to grouping 8, considering all the junctions.The mental walkthrough process for Object Schematics is very similar to that ofProcess Schematics. The example IDEF3 Object Schematic shown in Figure 6-4 can bepartitioned as in Figure 6-5.XFigure 6-4Example IDEF3 Object State Transition Schematic183ADBb1CEa1XFigure 6-5Example Partitioning of Figure 6-4First, the schematic is partitioned into five major groupings: A, B, C, D, and E.
Forthe most part, these groupings center around the four transition links (one of which is adisjunctive junction having two paths). Grouping D centers around a single object staterather than a transition link, treating the state and its attached referent as a single logicalunit. Groupings A and B in this example have been further partitioned to includesubgroupings a1 and b1.These groupings can then be numbered as items 1 through 7 (see Figure 6-6).
Startingwith grouping 1 on the far left of the schematic, readers will typically proceed from left toright while performing the following activities:1.Read the object states and their elaborations, paying particularattention to state and exit conditions.2.Examine the transition links and their elaborations, paying particularattention to transition and exit conditions.3.Consider all context-setting objects, non-transition relations, andnotes within the bounds of the selected grouping.1842643571XFigure 6-6Analyzing the GroupingsThe process of reading the schematic then proceeds using almost the same pattern asthat used for reading the Process Schematic, with a few slight differences. Unlike thepartitioning process typically used for the Process Schematic—where groupings andsubgroupings tend to form in a strictly hierarchical fashion—Object Schematic groupingstend to overlap with other groupings and to exhibit hierarchical structure.
Whereas thecontext for reading and understanding Process Schematic groupings is established bytheir place in the hierarchy, the context for understanding an Object Schematic groupingis established by the left-most object state(s) in the grouping. Hence, while proceedingleft to right in a schematic, readers will, to some extent, repeat their study of overlappingobject states.
The first reading of an overlapping object state focuses primarily on thetransition and entry conditions associated with the transition link leading to the objectstate. The second reading focuses primarily on its state and entry conditions. Byconducting both readings—where the first reading considers the object state as the rightmost element in the grouping and the second reading considers the object state as the leftmost element in the neighboring grouping—reviewers gain a clear picture of an object’sstate transition behavior. As with the Process Schematic, another complete review of theschematic serves to solidify understanding of the description.185BIBLIOGRAPHYAllen, J.
F. (1984). Towards a general theory of action and time. Artificial Intelligence, 23,123-154.Allen, J., & Hayes, P. (1987, December). Moments and points in an interval-based temporallogic. Technical Report (TR 180), Departments of Computer Science and Philosophy,University of Rochester.Balci, O., & Nance, R. E., (1987).
Simulation model development environments: A researchprototype. Journal of the Operational Research Society, 38(8), 753-763.Barwise, J., & Perry, J. (1983). Situations and attitudes. Cambridge, MA: MIT Press.Brachman, R. J. (1985). On the epistemological status of semantic networks. In Brachman, R.J., & Levesque, H. J. (Eds.), Readings in Knowledge Represenation. Los Altos, CA:Morgan Kaufmann Publishers, Inc. 191-215.Coleman, D. S.
(1989). A framework for characterizing the methods and tools of an integratedsystem engineering methodology (ISEM) (draft 2, rev. 0). Santa Monica, CA: PacificInformation Management, Inc.Cross, S. (1983). Qualitative reasoning in an expert system framework. Technical Report(T-124). Urbana, IL: University of Illinois Coordinated Science Lab.Cullinane, T., McCollom, N., Duran, P., & Thornhill, D.
(1990). The human elements of IDEF.Unpublished manuscript.D. Appleton Co., Inc. (1985). Integrated Computer-Aided Manufacturing (ICAM): InformationModeling Manual, IDEF 1— Extended (IDEF1X) (F33615-80-C-5155), Albany, New York:General Electric Company.De Kleer, J., & Brown, J. S. (1984).
A qualitative physics based on confluences. ArtificialIntelligence, 24, 7-83.De Kleer, J. (1979). Causal and teleological reasoning in circuit recognition (TR-529).Cambridge, MA: MIT AI Lab.Devlin, K. (1991). Logic and information, volume I: situation theory. Cambridge, MA:Cambridge University Press.Enderton, H.
(1972). A mathematical introduction to logic. New York, Academic Press.Forbus, K., (1984). Qualitative process theory. Artificial Intelligence, 24, 85-168.186General Electric. (1985). Integrated information support system (IISS), volume 5: common datamodel subsystem; part 4: information modeling manual (DTIC-A181952). GeneralElectric.Genesereth, M. R., & Fikes, R. E. (1992). Knowledge interchange format version 3.0 reference manual. report logic-92-1. Logic Group, Stanford University, CA.Gödel, K. (1931). Über Formal Unentscheidbare Sätze der Principia Mathematica undVerwandter Systeme, I. Monatshefte Für Mathematik und Physik 38, 173-198.IDEF Users Group.
(1990). IDEF: framework, draft report (IDEF-U.S.-0001). Dayton, OH:IDEF Users Group.International Standards Organization. (1987, July). Information processing systems: conceptsand terminology for the conceptual schema and the information base (ISO/TR 9007).International Standards Organization.Knowledge Based Systems, Inc. (1991).
Formal foundations for an ontology descriptionmethod, (KBSI-SBONT-91-TR-01-1291-02). College Station, TX: Knowledge BasedSystems, Inc. (1991).Knowledge Based Systems, Inc. (1991). Knowledge based information model integration. FinalTechnical Report, NSF SBIR, No. ISI-9060808. College Station, TX: Knowledge BasedSystems, Inc.Knowledge Based Systems, Inc. (1991). The nature of ontological knowledge: Amanufacturing systems perspective (KBSI-SBONT-91-TR-01-1291-01). College Station,TX: Knowledge Based Systems, Inc.Knowledge Based Systems, Inc. (1991). Ontology acquisition method requirements document(KBSI-SBONT-91-TR-01-1291-03). College Station, TX: Knowledge Based Systems, Inc.Knowledge Based Systems, Inc. (1991).
Ontology capture tool requirements document (KBSISBONT-91-TR-01-1291-04). College Station, TX: Knowledge Based Systems Inc.Knowledge Based Systems, Inc. (1991). Reliable object based architecture for intelligentcontrollers. DARPA SBIR 91-050. Contract No. DAAH01-91-C-R235.College Station,TX: Knowledge Based Systems, Inc.Knowledge Based Systems, Inc. (1992). IDEF4 method report. College Station, TX:Knowledge Based Systems, Inc.Knowledge Based Systems, Inc. (1992). Ontology capture tool: object-oriented designdocument (KBSI-SBONT-91-TR-0292-01). College Station, TX: Knowledge BasedSystems, Inc.187Knowledge Based Systems, Inc.
![](https://s.studizba.com/z.php?f=/templates/si/i/noavatar.png&w=100&h=100&t=1"){kind=avatar}
