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This subset is known as theelaboration language core which contains the basic elements needed for almost anylogical language. The core is extended by a number of IDEF3-specific constructsdesigned to express precise information about the processes and transitions represented inthe IDEF3 schematic languages. However, for this to be done effectively, it is essential tohave a clear semantics for the language. The intuitive semantics for IDEF3 schematicsare based upon situation theory, a recently developed theory of information [(Barwise &Perry, 1983); see Section A.4 of Appendix A for an informal overview of the theory].
Inthe elaboration language, basic concepts of IDEF3 such as UOB, process, and the like areidentified with certain basic semantic categories of situation theory. The constructs addedto the elaboration language core correspond to these categories.To illustrate the use of the elaboration language in conjunction with a processschematic, consider the process in the schematic in Figure 3-84. Call this process“PQD”.PaintPart1XPaintPartDry PartsQueue PartX432Figure 3-84Paint/Queue/Dry Process89In addition to constraints indicated in the schematic, there could be a wide variety ofadditional constraints on the process that cannot be expressed in the graphical language,for instance:In an activation of PQD, exactly one part is painted in any given occurrence of PaintPart.This constraint is expressed as follows:(forall(?coe : (activation-of ?coe PQD))(forall (?sit : (and (occurs-in ?sit ?coe) (occurrence-of ?sit Paint-part)))(exists!-1 ?x (supports ?sit (painted ?x +)))))In this constraint, the variable “?coe” ranges over courses-of-events, i.e., activations,or instantiations, of general processes like PQD.
The variable is further restricted by theexpression to the right of the colon—(activation-of ?coe PQD)—to those courses ofevents that are activations of the process PQD. Then for any such course of events c, theremaining two lines then say that, for any situation s that is an occurrence of the UOB, orsituation type, Paint Part in c, there is exactly one object (the meaning of “exists!-1”) xsuch that x is being painted in s—i.e., in the language of situation theory, such that ssupports the information that x is being painted.Note that this constraint, as expressed, applies to the entire PQD scenario depicted inthe diagram.
However, it may be more natural to add the constraint directly to thecharacterization of Paint Part, where it is intended to apply to each occurrence of PaintPart in a given activation of PQD. The general universally-quantified conditions at thebeginning of the constraint can thus be dropped and the constraint can be expressed muchmore simply and directly as follows:(exists!-1 ?x (supports ?sit (painted ?x +))).Note that, as a constraint on Paint Part, the situation variable “?sit” is not thought ofas implicitly universally-quantified but rather as a parameter playing the role of a givenoccurrence of Paint Part in a given activation; similarly for the object variable “?x”.A second example presupposes that a number of auxiliary notions have been defined,viz., the relation in-queue — which holds between an object, a queue, and an interval justin case the object is in the queue during the interval — and a function start-of that takes asituation to the point (a variety of interval) in time at which it starts.
The elaborationlanguage provides powerful facilities for creating such definitions. Consider, then, thefollowing constraint on PQD.In an activation of PQD, no instance of Paint Part begins at any time if there are fiveobjects in the queue at that time.90(forall(?coe : (activation-of ?coe PQD))(forall (?sit : (and (occurs-in ?sit ?coe) (occurrence-of ?sit Paint-part)))(not (exists-5 ?x (and (instance-of ?x Part)(supports ?sit (in-queue ?x Q (start-of ?sit) +)))))).That is, for any activation of PQD there is in that activation no occurrence s of Paintpart such that there are five (or more) objects in the queue at the start of s.
Again, thisconstraint is expressed generally about PQD, but if it is added directly to thecharacterization of Paint Part where it is intended to apply to the occurrences of PaintPart within a given activation, it can be expressed directly as follows:(not (exists-5 ?x (and (instance-of ?x Part) (in ?x Q (start-of (interval-of ?sit)))))).To illustrate the use of the elaboration language with object schematics, consider theenhanced transition schematic in Figure 3-83. As noted above, in such schematics thereis some semantic indeterminacy as to the scope of the surrounding contextualinformation.
For example, are grommets generally considered indirect materials or arethey so considered only in more restricted contexts like the depicted process? Suchinformation can be added explicitly in the elaboration language. Thus, the followingconstraint might be added explicitly to the elaboration document for the schematic,expressed as indicated.Grommets are considered Indirect Materials in all situations.(forall(?sit ?x : (supports ?sit (grommet ?x +)))(supports ?sit (indirect_material ?x)))That is, any situation at all (relative to the given enterprise) that supports theinformation that x is a grommet also supports the information that it is indirect material.As noted previously, an object symbol in a transition schematic indicates, in additionto the state in question, the type of situation in which an object is in that state.
Hence,enhanced transition schematics are a bit ambiguous with regard to the meaning of objectsymbols. For example, in Figure 3-83, in the context of the embedded transitionschematic, the Widget symbol indicates the type of situation in which there is a widget,whereas, in the context of that symbol being linked to the Direct Material symbol,widgets are indicated as a kind of direct material. To sort out this ambiguity in theelaboration language, we will use the term “Widget*” to signify the type of situation inwhich there is a widget.Given this, it is now possible to illustrate how one would use the elaboration languageto express the following constraint.91The widget and the grommet in an instance of WGF are in the oven at 500 degrees fora period of 5 minutes before they are assembled into a frammitz.(forall(?coe : (activation-of ?coe WGF))(forall (?sit ?sit1 ?sit2:(occurs-in ?sit ?coe)(occurs-in ?sit1 ?coe)(occurs-in ?sit2 ?coe)(occurrence-of ?sit Frammitz*)(occurrence-of ?sit1 Widget*)(occurrence-of ?sit1 Grommet*))(forall (?x ?y) : (supports ?sit1 (Widget ?x))(supports ?sit2 (Grommet ?y)))(exists (?sit3 ?oven: (during ?sit1 ?sit3)(during ?sit2 ?sit3)(precedes ?sit3 ?sit)(supports ?sit3 (Oven ?oven)(supports ?sit3 (= (temp-of ?oven) 500)))(and (supports ?sit3 (in ?x ?oven))(supports ?sit3 (in ?y ?oven))(supports ?sit3 (= (in-oven-during ?x 5)))))))That is, in any occurrence c of WGF, if ?sit, ?sit1, and ?sit2 are occurrences ofFrammitz*, Widget*, and Grommet*, respectively, in c, then if ?x and ?y are the Widgetand the Grommet in Widget* and Grommet*, respectively, then there is an object ?ovenand a situation ?sit3 such that (1) ?sit1 and ?sit2 occur during ?sit3, (2) ?sit3 precedes?sit, and (3) ?oven is an Oven whose temperature is 500 degrees in ?sit3, and such that ?xand ?y are in the oven in ?sit3.NotesA note box may be attached to a UOB, junction, object, link, or referent.
Notes allowthe IDEF3 analyst to perform the following.1.Emphasize the participation of particular objects or relationsassociated with the attached UOB or junction.2.Tie in specific examples of referenced data or objects (e.g., screenlayouts).3.Highlight special constraint sets associated with a given junctionelaboration. Notes can be used to call attention to, or list the92contents of, a junction elaboration (e.g., additional facts, constraints,or decision logic which describe how that junction works).Notes may be used to provide additional information about a particular IDEF3 modelelement or to attach illustrations, text, screen layouts, comments, etc. to the description.New IDEF3 users will often find that notes provide an easy way to express ideas orconcepts in lieu of junction types, dashed arrows, or constraint language statements.The example in Figure 3-85 illustrates how a note can be used to highlight theassociation of special constraint sets with junctions.
This description states that, forcertain conditions, it will be required to loop back to UOB Perform Mission AreaAnalysis. In this case, the note on Junction J1 is used to display the conditions underwhich the referent UOB/Perform Mission Area Analysis would be activated.TS/Statement ofNeed (SON)GO-TO/Perform MissionArea Analysis1Perform Mission AreaAnalysis11/1Prioritize NeedsExplore ConceptsGO-TO/XORO23J4/2.1J1Define Concepts4J1/N1UOB/Perform AlternativeTrade-offs9.1.15/9.1When data is weak,Mission Area Analysismust be performedagain.Figure 3-85Note Associated with a JunctionThe note box is divided into two sections. The band across the top of the note is usedfor note identification.
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