Download System Def Comments Bocast 2010-10-03

DoDAF 2.0 DM2: System1
• Thing : Type : IndividualType : Resource : Performer : System
• System — A functionally, physically, and/or behaviorally related group of regularly interacting or interdependent elements.
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System — A functionally, physically, and/or behaviorally related group of regularly interacting or interdependent elements.
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1. Semantic insufficiency. The word “group” signifies an observational construct. A group is a concept that an observer imposes upon the world to make sense
of what is observed. A group does not have its own ontic significance: a group is merely an abbreviated way to refer to some set of things without
enumerating and naming those things. In other words, groupness is in the eyes of the beholder; epistemologically, we can never be certain that what is
counted in my group is counted in your group.
2. [retracted]
3. Semantics: pesky disjunction. Read as combinatorial conjunction: the ways in which things may be related include functional, physical, and behavioral
ways.
4. Grammar. The phrase “functionally … related” modifies the word “group”, but “group” is given in the singular. The adjective “related” asserts a relationship
between this group and something else, but that something else is here unspecified. If the asserted relationship is to be with another group, then “group”
must be given in the plural. However, the authors may have intended the phrase “functionally … related” to characterize “elements”; if so, the phrase is on
the wrong side of “group”.
5. Semantics: pesky disjunction. Read as nonexclusive conjunction of permitted possibilities: these elements may be interacting and they may be
interdependent. Definitionally, this leaves us at a loss because definition requires certainty. If these elements may be not-interacting and may also be notinterdependent, then these elements may be neither. What is wanted here is a higher-level abstraction to absorb this indeterminacy.
6. Definitional epistemology. How are we to determine the dividing line between regularly and not-regularly? What yardstick are we to use to measure
regularness?
7. Grammar: unexpected distribution. Grammatically, the word “regularly” distributes across the disjunction: of regularly interacting or regularly
interdependent elements. The resulting phrase—regularly interdependent—is problematic.
8. Semantic insufficiency. An element is generally taken to be something tangible and observable. The use of this term implies that system is here intended to
be something that may be observed only as a static snapshot of physical things. In some communities, the notion of system may encompass processes that
play out dynamically, that is, a system is something that does rather than something that is. What is needed is definition of “element” in this context:
should this term signify physical entity or should this term signify process as well as artifact?
element — an artifact that is one of the individual parts of which a composite entity is made up; especially a part that can be separated from or attached to a
system [WordNet; 2010-04-23]; a fundamental, essential, or irreducible constituent of a composite entity [AHD; 2010-04-23]; a separate identifiable part of
something, or a distinct group within a larger group [Encarta; 2010-04-23]; a constituent part [M-W; 2010-04-23]
group — any number of entities (members) considered as a unit [WordNet; 2010-04-23]
DoDAF 2.0 DM2: System2
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System — A functionally, physically, and/or behaviorally related group of regularly interacting or interdependent elements.
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Domain knowledge. On what grounds are these sorts of relations—functional, physical, behavioral—asserted as the defining relations among groups or
among elements of a system? Lacking definitions for these terms, we can only kinda sorta guess at the authors’ intent.
by deconstruction & reconstruction
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system ≈ a group of things related in functional, physical, and behavioral ways.
A. Semantics: Diogenistic poultry. By this statement, a gaggle of geese is a system, a brick retaining wall is a system, and a stage production of Our Town is a
system.
B. Semantics: conceptual asymmetry. The problem becomes apparent when we try to avoid the vagueness of the word “ways”. We want to say something
like: related by function, behavior, and … What are we now to do with “physical ways”? The wording “related by function, behavior, and physics” would be
quite odd.
C. Semantics. The nature of system continues to bedevil erstwhile definers. The fundamental difficulty for architects is that system is an analytical construct
rather than a real, tangible, observable thing. We can point to pieces that are physical and we can point to parts that are behaviors, but system is a
boundary we draw around these things to simplify (make manageable) our discourse. Looking at DoD notions of system, historically, this boundary keeps
shifting and expanding as previous notions of system prove insufficient and inadequate.
From a nominalist perspective, a DoD system is just a way to aggregate related expenditures. Whether these are necessary or sufficient expenditures we
don’t care: we have a name that serves to drag these expenditures through our conversation. In nominalist modeling, a system is merely a name (e.g.,
UML class) to which we attach a variety of things (e.g., associations to other classes).
From an ontological perspective, well, it is difficult to argue that systems actually exist. To do so, we must identify the where and when of a system;
unfortunately, because system is a construct of observation (a conversational convenience rather than a specification) we can never be sure that what I see
as system is what you see as system. When you are in the middle of the Atlantic Ocean, it may be conversationally clear and unremarkable that you are in
the Atlantic Ocean. However, it is really one water mass that encircles the globe: the divisions between Atlantic Ocean, Arctic Ocean, Pacific Ocean,
Southern Ocean, and Indian Ocean are at best arbitrary. We have no sound or trustworthy epistemological basis for asserting that any particular drop of
water is in any particularly named ocean at any particular time; we have only a conversational convention.
behavior — the action or reaction of something (as a machine or substance) under specified circumstances [WordNet; 2010-04-23]
behaviorally — the way in which something functions or operates [M-W; 2010-04-23]
behavioral — of or relating to behavior [WordNet; 2010-04-23]
function — what something is used for [WordNet; 2010-04-23]
functionally — with respect to function [WordNet; 2010-04-23]
physically — in accord with physical laws [WordNet; 2010-04-23]
system — see following slide…
DoDAF 2.0 DM2: System3
From WordNet [2010-04-24]:
(n) system (instrumentality that combines interrelated interacting artifacts designed to work as a coherent entity) "he bought a new stereo system"; "the
system consists of a motor and a small computer"
(n) system, scheme (a group of independent but interrelated elements comprising a unified whole) "a vast system of production and distribution and
consumption keep the country going"
(n) system ((physical chemistry) a sample of matter in which substances in different phases are in equilibrium) "in a static system oil cannot be replaced by
water on a surface"; "a system generating hydrogen peroxide"
(n) system, system of rules (a complex of methods or rules governing behavior) "they have to operate under a system they oppose"; "that language has a
complex system for indicating gender"
(n) arrangement, organization, organisation, system (an organized structure for arranging or classifying) "he changed the arrangement of the topics"; "the
facts were familiar but it was in the organization of them that he was original"; "he tried to understand their system of classification"
(n) system (a group of physiologically or anatomically related organs or parts) "the body has a system of organs for digestion"
(n) system (a procedure or process for obtaining an objective) "they had to devise a system that did not depend on cooperation"
(n) system (the living body considered as made up of interdependent components forming a unified whole) "exercise helped him get the alcohol out of his
system"
(n) organization, organisation, system (an ordered manner; orderliness by virtue of being methodical and well organized) "his compulsive organization was not
an endearing quality"; "we can't do it unless we establish some system around here"