Action

Definition of Action

Definition Last Updated 17-Dec-2015 12:51

An action is a unit of activity for which no internal description is provided, i.e. it is an event (potentially of extended duration), characterised entirely by a specified change in state. Defined thus, in terms of changes of state, an action may be seen as the occurrence of an exercise of a capability; actions may be performed by a performer – but they might also simply be reactions, i.e. an effect arising from a particular cause.

It may be possible, and indeed it usually is, to divide an action into smaller actions; whilst this may appear to convert an action into an activity (given that the description of a thing should be fixed unless it is acted upon), activity is the fundamental concept: an activity may be described as an action only for the actor who is unable to interrupt it.

Scope

Action is a defined term of Enterprise Architecture. Action is a defined term of Business Analysis.

Discussion

Article Last Updated 17-Dec-2015 12:51

The characterisation of action applies equally to what is done intentionally, such as picking up a pen, and what just happens, such as two raindrops coalescing on the window on a rainy November day in England.

As far as picking up my pen is concerned, the action is reaching out and grasping (considered as a whole); in the case of the raindrops, the action is touching, which then causes them to coalesce.

Whilst it might be thought that an action should have a single, primary actor who does something that causes something else to happen, it is easy to construct counterexamples.

Consider two atoms of hydrogen (H) of constant velocities that collide to form a molecule (H2). If either were stationary, it might be natural to call the other the primary actor since it does the “colliding”. However, (inertial) motion being relative, there is no reason to prefer either as the actor, so there is none in this case.

Contrariwise, when there is a genuine asymmetry there may be case for identifying some actor as the primary actor; in general, however, an action need not have a primary actor.

An action is minimally specified as a transformation by its initial and final states; whilst every transformation is an effect of something, and therefore has a cause, the primary actor may not be identifiable.

Activity

Definition of Activity

Definition Last Updated 17-Dec-2015 12:51

Activity is continuous change in one or more observables during a specified period of time, which, if the activity is current, is open-ended to the future and may be open-ended in the past; an entity engaged in activity has that activity as a behaviour is an performer.

An activity is recognised pattern of change, i.e. a mapping from particular initial states to particular outcomes, which may or may not be goals.

Scope

Activity is a defined term of Enterprise Architecture. Activity is a defined term of Business Analysis.

Discussion

Article Last Updated 17-Dec-2015 12:51

Activity vs. Behaviour

Section Last Updated 17-Dec-2015 12:51

All behaviour is activity, but not all activities are behaviours: behaviour requires the identification of an entity to which the activity can be attributed; activity does not.

Examples:

  • “The lioness is creeping through the long grass.” describes a behaviour: the lioness is attributed the activity
  • “Some of the long grass is waving.” describes an activity: some grass is not an entity to which the activity can be attributed
  • “There is movement in the long grass.” is ambiguous: “in” suggests that only part of the long grass is moving, but it is not well-identified enough to be an entity; but, if the emphasis were on “the long grass”, suggesting a defined border separating long grass from shorter grass, the long grass might be in fact be an entity in its own right1If this type of ambiguity (not some actual threatening movement in long grass somewhere) turns out to be a significant problem for anybody I would a) be surprised b) like to know about it. .

An Activity

Note that the performer engaged in an activity need not be aware of or even capable of recognising the initial states or outcomes that define an activity: activity may just happen.

Is Waiting an Activity – or the Absence of Activity?

Waiting is an activity because waiting for something entails continuous observation in order to determine when that something (the state of interest) occurs. Even if an observer only observes intermittently, it must still monitor the passage of time in order to determine when to make an observation. Waiting for something also implies an expectation or belief – whether that justified or not – that that that something will occur.

According to the definition given here, when a performer does not engage in a particular activity, or perform a particular action until caused to do so by some external event, the performer is simply not doing a particular thing, the performer is not necessarily inactive: the performer may be doing something else.

When, for example, a piece of hardware or software is said to be waiting for input it may be:

  • Polling (repeatedly observing) the input channel as fast as possible (e.g. in a tight causal loop) or it may be
  • Polling a timer prior to checking the input channel at particular intervals
  • Inactive until triggered into activity by a specific signal such as an interrupt

Notes   [ + ]

1.If this type of ambiguity (not some actual threatening movement in long grass somewhere) turns out to be a significant problem for anybody I would a) be surprised b) like to know about it.

Activity vs Behaviour Snippet

Activity vs. Behaviour

Section Last Updated 17-Dec-2015 12:51

All behaviour is activity, but not all activities are behaviours: behaviour requires the identification of an entity to which the activity can be attributed; activity does not.

Examples:

  • “The lioness is creeping through the long grass.” describes a behaviour: the lioness is attributed the activity
  • “Some of the long grass is waving.” describes an activity: some grass is not an entity to which the activity can be attributed
  • “There is movement in the long grass.” is ambiguous: “in” suggests that only part of the long grass is moving, but it is not well-identified enough to be an entity; but, if the emphasis were on “the long grass”, suggesting a defined border separating long grass from shorter grass, the long grass might be in fact be an entity in its own right1If this type of ambiguity (not some actual threatening movement in long grass somewhere) turns out to be a significant problem for anybody I would a) be surprised b) like to know about it. .

Notes   [ + ]

1.If this type of ambiguity (not some actual threatening movement in long grass somewhere) turns out to be a significant problem for anybody I would a) be surprised b) like to know about it.

Agreement

Definition of Agreement

Definition Last Updated 17-Dec-2015 12:51

Agreement is the mutual commitment of two or more parties (individual or organisational entities including political states) to adopt specific policies (normative specifications), typically subject to the provisions of implicit or explicit higher-level policies, such as may govern failures to meet the commitments made.

An agreement is a specific policy.

Examples

Contract, treaty, memorandum of understanding.

Note that a law is not an agreement: it is a policy of a state (or supra-national) organisation whose norms apply to its members (citizens or subjects) irrespective of explicit commitment to them.

Scope

Agreement is a defined term of Enterprise Architecture. Agreement is a defined term of Business Analysis

Discussion

Article Last Updated 17-Dec-2015 12:51

Types of Agreement

Recognised types of agreement include

  • Agreement, e.g. Non-Disclosure Agreement (NDA), Service Level Agreement (SLA)
  • Contract, e.g. Contract of Employment, Contract of Sale, etc. where the policies typically include the provision of something and financial remuneration for it, and IT Service Contracts where the agreement may be simply that provided certain conditions are met a certain capability will be exercised on behalf of the service requester
  • Memorandum of Understanding, may be, but typically is not legally binding1For further insight into MoUs see Wikipedia 

Treaty, sometimes legally binding

Notes   [ + ]

1.For further insight into MoUs see Wikipedia

Architecture Model

Definition of Architecture Model

Definition Last Updated 17-Dec-2015 12:51

An Architecture Model is a description of one or more entities in terms of other entities (contained components and components of the environment) and their attributes, specifically including innate properties and behaviours as well as the relationships between entities.

A formal architecture model is such a description codified in accordance with an (architecture) standard (which may reference subsidiary standards), such as an architectural Framework or Metamodel.

A formal model should identify the specific standard (by reference to dates and times, version numbers, standard document status, etc. as necessary) so that the compatibility of two or more models is determinable.

Scope

Architecture Model is a defined term of Enterprise Architecture.

Discussion

Article Last Updated 17-Dec-2015 12:51

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