Talk:Shlaer–Mellor method

message: This is promotional and commercial material.  —The preceding unsigned comment was added by 65.83.52.198 (talk • contribs) .
:How exactly is this page promotional or commercial?  What is it promoting, Shlaer-Mellor?  GeorgeBills 06:02, 15 June 2006 (UTC)
thread_title:  Discussion 2006 

message: It looks as if the link to Stephen Mellor goes to the American actor of that name, not the English methodologist. --Jhebley 16:44, 18 January 2007 (UTC)
thread_title:  Wrong Steve Mellor 

message: Taken as written, the following sentence says that 'describing [a certain thing] becomes a design'.  This is clearly not what the writer intended to say. 'Describing' in functional analysis isn't analogous to 'a design' in semantic analysis.
"That is to say, describing the control of a passenger train as load passengers, close doors, start train, stop train, open doors, unload passengers becomes a design focused on the behavior of doors, brakes, and engines, and how those "domains" (doors, brakes, etc.) are related and interact.
I think that the writer's intent was to convey the difference in how a system is decomposed in *functional* and *semantic* decomposition, respectively.
A first try to reword it:
"Functional decomposition means that the system under study is broken down into a series of functions--that is, actions or operations performed by the system.  In the case of a system to control a passenger train, one might describe it as 'load passengers, close doors, start train, stop train, open doors, unload passengers.'  In functional decomposition, each element starts with an action verb; the common noun--the class of thing being acted upon--is secondary.
"In contrast, semantic decomposition first breaks down a system into a set of classes of things (ie., a set of common nouns).  The passenger train analysis becomes 'train, passenger, doors'.  The class described by the common noun "door" has two behaviours: "open" and "close".  Thus, functional analysis's "open doors" and "close doors" (appearing at different places in the specification!) become the (closely grouped) facts that "doors [can] open" and "doors [can] close".  Since semantic analysis at first gives only the  possible behaviors of various kinds of people, places, and things, of course one has not specified a system that meets functional requirements until one has done a second "process modeling" step.
"The advantage claimed is that semantic analysis collects all the currently relevant knowledge about "doors" in one place, whereas in functional analysis (and thus, in the resulting designs and implementations), it is spread out all over.  If it becomes necessary to improve the knowledge about doors in the analysis, either because (a) a bug was found in the first system, or (b) because the analysis is later being re-used in a different system or (c) the original system is being functionally extended, then the change can be done more quickly, or more reliably, or with less time and resource.
Comments?
Mark.camp (talk) 21:10, 1 August 2009 (UTC)
thread_title: Fractured sentence

message: I believe the author's intention with the sentence "The analysis domain is considered to be dependent upon the design domain." was in fact the reverse of what is written, as in "The design domain is considered to be dependent upon the analysis domain."
Duncan George  —Preceding unsigned comment added by 99.247.135.102 (talk) 15:32, 6 October 2009 (UTC)
thread_title:  Design dependence