DoDAF terms and concepts, and issues with them
Abstract
For reasons
outlined below, I find the idea of people being mandated to conform to DM2
perturbing.
Contents
What
does it mean to use DoDAF?
Issues with DM2 terms and concepts
Notes
on relations between concepts
I have heard people say they are using DoDAF but go on to say they are using
· TOGAF for the architecture development process and/or
· UML or ArchiMate for the diagrams.
So in what sense
are they using DoDAF?
Surely it must mean that they are using the DoDAF Meta-Model - DM2?
DM2 provides a
vocabulary of architectural entity types.
It can be found in DoD Architecture Framework Version 2.02 <http://dodcio.defense.gov/Portals/0/Documents/DODAF/DoDAF_v2-02_web.pdf>
The DM2 meta model is based on a class hierarchy of generalisation relations.
Concepts in this meta model are defined as below.
|
DoDAF definition |
Closest equivalent in BCS
ESA ref. model |
|
Activity: Work, not specific to a
single organization, weapon system or individual that transforms inputs
(Resources) into outputs (Resources) or changes their state |
Process |
|
Agreement: A consent among parties
regarding the terms and conditions of activities that said parties
participate in |
SLA |
|
Architectural Description: Information describing an
architecture such as an OV-5b Operational Activity Model |
View |
|
Capability: The ability to achieve a
Desired Effect under specified (performance) standards and conditions through
combinations of ways and means (activities and resources) to perform a set of
activities. |
Component? |
|
Condition: The state of an
environment or situation in which a Performer performs. |
Precondition? |
|
Constraint: The range of permissible
states for an object. |
Rule |
|
Data: Representation of
information in a formalized manner suitable for communication,
interpretation, or processing by humans or by automatic means: Examples could
be whole models, packages, entities, attributes, classes, domain values,
enumeration values, records, tables, rows, columns, and fields. |
Data |
|
Desired Effect: The result, outcome, or
consequence of an action (activity) |
Aim |
|
Guidance: An authoritative
statement intended to lead or steer the execution of actions. |
Directive |
|
Information: The state of a something
of interest that is materialized -- in any medium or form -- and communicated
or received. |
Data
flow |
|
Location: A point or extent in
space that may be referred to physically or logically |
Location |
|
Materiel: Equipment, apparatus or
supplies that are of interest, without distinction as to its application for
administrative or combat purposes |
- |
|
Measure: The magnitude of some
attribute of an individual |
- |
|
Measure Type: A category of Measures |
- |
|
Organization: A specific real-world
assemblage of people and other resources organized for an on-going purpose |
Organisation
/ Unit |
|
Performer: Any entity - human,
automated, or any aggregation of human and/or automated - that performs an
activity and provides a capability |
Role
/ Actor |
|
Person Type: A category of persons
defined by the role or roles they share that are relevant to an architecture |
Role |
|
Project: A temporary endeavor undertaken to create Resources or Desired Effects
|
Programme
/ Project |
|
Resource: Data, Information,
Performers, Materiel, or Personnel Types that are produced or consumed |
- |
|
Rule: A principle or condition
that governs behavior; a prescribed guide for
conduct or action |
Directive |
|
Service: A mechanism to enable
access to a set of one or more capabilities, where the access is provided
using a prescribed interface and is exercised consistent with constraints and
policies as specified by the service description; the mechanism is a
Performer; the capabilities accessed are Resources -- Information, Data,
Materiel, Performers, and Geopolitical Extents |
System |
|
Skill: The ability, coming from
one's knowledge, practice, aptitude, etc, to do
something well |
- |
|
Standard: A formal agreement
documenting generally accepted specifications or criteria for products,
processes, procedures, policies, systems, and/or personnel |
Standard |
|
System: A functionally,
physically, and/or behaviorally related group of
regularly interacting or interdependent elements |
System |
|
Vision: An end that describes the
future state of the enterprise, without regard to how it is to be achieved; a
mental image of what the future will or could be like. |
Vision |
People who know
system modelling concepts already will read their previous understanding into
the DM2 text.
But I doubt the
DM2 text will explain the concepts to anybody who doesn't know the concepts
already through years of experience and training outside of DoDAF.
The DM2 meta model is based on a class hierarchy of generalisation relations, which looks like an academic
fantasy to me.
Oddly, there is
no multiple inheritance, though things in the real worlds can be instances of
many types (see other Avancier papers).
One longs for a
proper meta model, with more usefully annotated
association relations (see last section).
Some association
relations are deducible from the definitions above, some are one-to-one
associations.
DM2 seems badly
written.
E.g. two consecutive sentences:
· "Services are activities done by a Service provider (Performer) to achieve desired results for a Service consumer (other Performer)."
· "A Service is a type of Performer which means that it executes an activity and provides a capability."
So is a service is an activity, or a performer of activities, or both?
Is it both a transient behavioural process and a persistent
structural component?
Here are three DoDAF definitions:
·
Capability:
The ability to achieve a Desired Effect … through…activities and resources… to
perform a set of activities.
·
Desired
Effect: The result, outcome, or consequence of an activity.
·
Activity:
Work… that transforms inputs (Resources) into outputs (Resources) or changes
their state.
If 1 Capability
is the ability to achieve 1 Desired Effect, and 1 Desired Effect is the outcome
of 1 Activity.
Then does 1 Capability correspond to 1 Activity?
Another
definition:
· Resource: Data, Information, Performers, Materiel, or Personnel Types that are produced or consumed.
In what sense is human Performer produced or consumed?
Aren’t many
resources maintained, rather than being produced or consumed?
Another
definition:
·
Performer: Any entity
… that performs an activity and provides a capability.
Is this an
Individual or a Type?
AIMS
Visions are realized by Desired Effects (e.g., objectives).
A Project has Desired Effects (e.g., goals).
A Project consists of several or many Activities (e.g., Tasks).
Desired Effects (e.g., goals) guide/drive Activities
CAPABILITIES
A Capability entails performance of Activities (Tasks), as so stated in the CJCSI 3170.
A Capability is realized by one or more Performers (including configurations of Performer)
Capabilities have Desired Effects, as so stated in the CJCSI 3170.
INTERFACE
A Service provides access to Performers.
COMPONENTS
Performers perform Activities. (This distinguishes Performers from their superclass, Resources.)
Performers perform at Locations.
A Person Type can be part of a System, (e.g., a radar operator or, more generally, in a cybernetic sense).
Person Types have Skills.
PROCESSES
Activities are performed in accordance with Rules (e.g., Controls in IDEF0).
A Rule applies to an Activity under certain Conditions, (e.g., Rules of Engagement may vary dependent on threat Conditions).
The consumption or production of Resources by Activities is subject to Rules, (e.g., the Information Assurance Rules that are part of the OV-3).
The performance of Activities by Performers is subject to Rules.
Even though Rules constrain Activities, there may be tailoring for the performance of those Activities by specific Performers.
An Activity is performable under certain Conditions, (e.g., the Conditions applicable to Tasks in the UJTL).
An Activity is performed by a Performer under certain Conditions.
The performance of Activities as part of a Capability is done under certain Conditions, as so stated in the CJCSI 3170.
Activities result in effects on Effect Objects (Resources), i.e., a cause-effect chain.
An Activity consumes or produces Resources. Those Resources can be Materiel, Information, Data, Geo-Political, or other Performers.
When the production and consumption is of Information or Data, the DoDAF V1.5 OV-3, OV-5, SV-4, SV-6, and others are partially represented.
PASSIVE OBJECTS
Information describes a thing.
Information Pedigree is a type of Information that describes the production of Information (resources) by Activities, their Performers, and the Rules, Conditions, and Measures that apply to that information production.
Materiel can be part of a System, the parts and equipment that are part of a System.
THINGS THAT ARE MEASURABLE
A Condition
A Resource (e.g., mass, size).
A Project (e.g., time, cost).
Desired Effects
An Activity (e.g., how long it takes.).
The effect on Effect Objects by Activities.
The Skills of a Person Type (e.g., Skill level of a Person Type.
The performance of Activities by Performers (Additional to Activities’ Measures).
The performance of Activities under certain Conditions (e.g., the Measure Types applicable to Tasks [Activities] in the UJTL).
The performance of Activities as part of a Capability (metrics) for their performance, as so stated in the CJCSI 3170.
The consumption and production of Resources by Activities (e.g., the Timeliness and Size measures that are part of the OV-3).
Measurements are done in accordance with Rules, (e.g., Rules that specify how test measurement equipment must be calibrated before a test).
Measures can be categorized into Measure Types.