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Modeling Symbolic Representations

System modeling is all too often a flight for abstraction, when business analysts should instead look for the proper level of representation, ie the one with the best fit to business concerns.

Modeling is synchronic: contexts must be mapped to representations (Velazquez, “Las Meninas”).

Caminao’s blog (see Topics Guide) will try to set a path to Architecture Driven System Modelling. The guiding principle is to look at systems as sets of symbolic representations and identify the core archetypes defining how they must be coupled to their actual counterparts. That would provide for lean (need-to-know specs) and fit (architecture driven) models, architecture traceability, and built-in consistency checks.

This blog is meant to be a work in progress, with the basic concepts set open to suggestions or even refutation:

All examples are taken from ancient civilizations in order to put the focus on generic problems of symbolic architectures, disregarding technologies.

Symbolic representation: a primer

Original illustrations by Albert (http://www.albertdessinateur.com/) allow for concrete understanding of requirements, avoiding the biases associated with contrived textual descriptions.

Squared Outline: Actors


UML Actors (aka Roles) are meant to provide a twofold description of interactions between systems and their environment: organization and business process on one hand, system and applications on the other hand.

That can only be achieved by maintaining a conceptual distinction between actual agents, able to physically interact with systems, and actors (aka roles), which are their symbolic avatars as perceived by applications.

As far as the purpose is to describe interactions, actors should be primary characterized by the nature of language (symbolic or not), and identification coupling (biological or managed):

  1. Symbolic communication, no biological identification (systems)
  2. Analog communication, no biological identification (active devices or equipments)
  3. Symbolic communication, biological identification (people)
  4. Analog communication, biological identification (live organisms)

While there has been some confusion between actors (or roles) and agents, a clear-cut distinction is now a necessity due to the centrality of privacy issues, whether it is from business or regulatory perspective.

FURTHER READING

Squared Outline: States

States are used to describe relevant aspects in contexts and how the changes are to affect systems representations and behaviors.

On that account, events and states are complementary: the former are to notify relevant changes, the latter are to represent the partitions (²) that makes these changes relevant. Transitions are used to map the causes and effects of changes.

  1. State of physical objects.
  2. State of processes’ execution.
  3. State of actors’ expectations.
  4. State of symbolic representations.

Beside alignment with events, defining states consistently across objects, processes, and actors is to significantly enhance the traceability and transparency of architectures designs.

FURTHER READINGS

Squared Outline: Cases vs Stories

Use cases and users’ stories being the two major approaches to requirements, outlining their respective scope and purpose should put projects on a sound basis.

To that end requirements should be neatly classified with regard to scope (enterprise or system) and level (architectures or processes).

  • Users stories are set at enterprise level independently of the part played by supporting systems.
  • Use cases cut across users stories and consider only the part played by supporting systems.
  • Business stories put users stories (and therefore processes) into the broader perspective of business models.
  • Business cases put use cases (and therefore applications) into the broader perspective of systems capabilities.

Position on that simple grid should the be used to identify stakeholders and pick between an engineering model, agile or phased.

FURTHER READING

EA & The Pagoda Blueprint

“The little reed, bending to the force of the wind, soon stood upright again when the storm had passed over”

Aesop

Resilience and adaptability to changing environments (Masao Ido)

Preamble

The consequences of digital environments go well beyond a simple adjustment of business processes and call for an in-depth transformation of enterprise architectures. 

To begin with, the generalization of digital environments bears out the Symbolic System modeling paradigm: to stay competitive, enterprises have to manage a relevant, accurate, and up-to-date symbolic representation of their business context and concerns. 

With regard to architectures, it means a seamless integration of systems and knowledge architectures.

With regard to processes it means a built-in ability to learn from environments and act accordingly.

Such requirements for resilience and adaptability in unsettled environments are characteristic of the Pagoda architecture blueprint.

Pagoda Blueprint

As can be observed wherever high buildings are being erected on shaking grounds, Pagoda-like architectures set successive layers around a central pillar providing intrinsic strength and resilience to external upsets while allowing the floors to move with the whole or be modified independently. Applied to enterprise architectures in digital environments, that blueprint can be much more than metaphoric.

The actual relevancy of the pagoda blueprint is best understood when the main of data, information, and knowledge is set across platforms, systems, and organization layers:


Pagoda Architecture Blueprint

That blueprint puts a new light on model based approaches to systems engineering (MBSE):

  • Conceptual models, targeting enterprises organization and business independently of supporting systems.
  • Logical models, targeting the symbolic objects managed by supporting systems as surrogates of business objects and activities.
  • Physical models, targeting the actual implementation of symbolic surrogates as binary objects.

Weaving together enterprises and knowledge architectures would greatly enhance the traceability of transformations induced by the immersion of enterprises in digital environments.

Systems & Knowledge Architectures

If digitized business flows are to pervade enterprise systems and feed decision-making processes, systems and knowledge architectures are to be merged into a single nervous system as materialized by the Pagoda central pillar:

Enterprise Nervous System
  • Ubiquitous, massive, and unrelenting digitized business flows cannot be dealt with lest a clear distinction is maintained between raw data acquired across platforms, and the information (previously data) models which ensure the continuity and consistency of systems.  .  
  • Once structured and refined, business data flows must be blended with information models sustaining systems functionalities.
  • A comprehensive and business driven integration of organization and knowledge could then support strategic and operational decision-making at enterprise level.

Rounding off this nervous system with a brain, ontologies would provide the conceptual frame for models representing enterprises and their environments.

Agile Architectures & Homeostasis

Homeostasis is the ability of a viable organism to learn from their environment and adapt their behavior and structures according to changes.
As such homeostasis can be understood as the eextension of enterprise agility set in digital environments, ensuring:

  • Integrated decision-making processes across concerns (business, systems, platforms), and time-frames (tactical, operational, strategic, … ).
  • Integrated information processing, from data-mining to knowledge management.

To that end, changes should be differentiated with regard to source (business or technology environment, organization, systems) and flows (data, information, knowledge); that would be achieved with a pagoda blueprint.

Resilience and adaptability to changes

Threads of operational and strategic decision-making processes could then be weaved together, combining OODA loops at process level and economic intelligence at enterprise level.

Further Reading

Squared Outline: Layers

The immersion of enterprises into digital environments is blurring the traditional distinctions between architecture layers. Hence the need of clarifying the basic notions.


Pagoda Architecture Blueprint

Beyond the differences in terminologies (layers, levels, tiers, etc), four basic taxonomies can be applied:

  1. Enterprise architecture: business processes and organization, systems, platforms (Pagoda blueprint).
  2. Functional architecture: interfaces, control, persistency, services (Model/View/Controller).
  3. Representation: physical, logical, conceptual (Pagoda blueprint).
  4. Economic intelligence: data, information, knowledge

While some alignments are intrinsic, making explicit use of taxonomies is useful because they serve specific purposes.

Further Reading

Squared Outline: Activity

As far as modeling is concerned a distinction has to be maintained between the symbolic description of activities and the processes describing their actual execution.

Given that distinction, the objective is to align action semantics with the constraints of their execution:

  1. Action on symbolic representations without coupling with the context (no change).
  2. Action on symbolic representations with coupling with context (change in expectations).
  3. Interaction with actual context without direct coupling (change in process status).
  4. Interaction with actual context with direct coupling  (change in objects).

That taxonomy can then be applied to map use cases semantics to architecture capabilities.

Squared Outline: Time-frames

Time-frames are defined by root events and therefore best defined along the same guideline, namely their scope and the nature of coupling. 

Along that understanding, time-frames can be defined with regard to context (symbolic or actual) and coupling (asynchronous or synchronous):

  1. Symbolic, no coupling: time-frames set by internal events, involving a single actor.
  2. Symbolic, coupling: time-frames set by external events, involving a single actor.
  3. Actual, asynchronous: time-frames set by external events, involving different actors without real-time constraint.
  4. Actual, synchronous: time-frames set by external events, involving different actors with real-time constraint.

That taxonomy could be used to align time-frames with processes‘ execution mode.