Information Technology Reference
In-Depth Information
<Quotation, Evaluate>
<Item, Receive>
DM
DM
DM
<Specs, Enquiry>
<Purchase-order, Issue>
<Payment, Authorize>
Fig. 10 The user process model
<System, Deliver>
DM
<Quotation, Generate>
<Info, Verify>
<Software, Test>
DC
DM
DM
DM
DC
<Additional-Info, Explore>
<System-Detail, Check>
DC
DM
<Software, Install>
DC
<System, Assemble >
DM
<Missing-Parts, Order>
Fig. 11 A system supplier
Fig. 12 The supplier process
<Parts, Deliver>
DC
<Parts-Quotation, Quote>
Necessity and Urgency. Necessity identifies whether enactment of a successor
node is mandatory after the current node has been enacted or it is optional.
Urgency associates a temporal property with the edge and specifies whether the
enactment of the successor node is immediately done after the current node is
enacted or whether it can be deferred. We have shown in [ 23] that the deferred
necessity is a high level abstraction of the notion of a long running process. It can
be used in subsequent development stages to specify a deadline before which the
node must be enacted. Combining the two properties, we get four possible prop-
erties of an edge as shown in Table 1. These four properties represent a variety of
process situations [ 23] , sequence, choice, parallelism etc.
The process model of the user organization asks for quotation enquiries for items
meeting specifications, evaluates the received quotations, issues purchase orders to
selected vendors, takes delivery of items and finally, makes payment. Each successor
node in the figure is necessarily to be enacted but it does not need to be enacted
Ta b l e 1 The four edge
properties
Abbreviation
Urgency
Necessity
IM
Immediate
Must
IC
Immediate
Can
DM
Deferred
Must
DC
Deferred
Can
 
 
 
 
 
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