No, not really a photograph of me - say, you guessed that didn't
you! I like Yoda, that's all. Mind you, I'm not sure what he is
staring at...
So, what is Systems Architectonics? It describes a subject
which barely seems to exist - the study of systems architecture. It
seems that we presently lack the ability to examine a situation and
then prescribe a systems architecture best suited to that situation.
The problem is presented in the following picture, which shows the
so-called Missing Science, and suggests sources that might contribute
to it:-
Architectural archetypes
A mathematics of architecture
Architectural metaphors, and...
Learning from past and present architectures
That's the plan - but can we do it without falling into traps such
as:-
reinventing the wheel
making false deductions because the environment that spawned
some old architecture is no longer relevant
misreading metaphors
etc.
Aspiring Architecture
At left is Salisbury Cathedral, centre is the Seattle Expo tower
and right is the Forte Grand, Abu Dhabi
The buildings nations produce exhibit features consistent with
their national development and contemporary psyche, indicating
confidence, severity, retrenchment, exuberance...
Young, confident societies/civilizations create monuments to
their future, reaching to the sky. Buildings tend to massive, but
with purity and severity of line, e.g. pyramids, cathedral spires,
Eiffel tower...
Wealth creates architectural variety. Impoverishment results
in architectural monotony
Poor/demoralized societies do not build monuments to a future
in which they have no confidence. Nor do they invest in
infrastructure to connect and bind their societies together.
through the ages, and today, architecture is a barometer of
societal psyche
Animal Architectures
The figure shows several different animal architectures - see
Cambridge Encyclopedia of Life Sciences. As the architecture becomes
more complex, both advantages and problems arise:-
animals become better able to accommodate different
environments, process different resources, remain viable between
meals, etc.
energy distribution and waste collection, instead of simply
occuring through a cell wall, require canals, arteries, etc.
heat generated in the centre is less well able to escape
etc.
It soon becomes evident that, as architectures become more
complex, waste disposal becomes a significant issue.
Scaling of architectures becomes problematical, too. While the
surface are of exoskeletons increases with the square of their
radius, the volume (and weight) contained increases as the cube of
the radius. Result? Beyond a certain weight limit, exoskeletons are
ineffective.
Humans have developed a composite skeleton. While most of our
skeleton is internal (endoskeletal), our brains are protected by our
skulls, effectively an exoskelton. Similarly, our rib cage protects
our lungs and softer organs within. Here, the rib cage is an
incomplete exoskeleton to reduce weight and increase flexibility.
With a little thought, it can be seen that these "rules" through
which animal architectures have evolved can be more generally
applied:-
Architecture expresses purpose in man-made systems -
architecture is the structural framework giving form and substance
to a system, but architecture is more - by its very form it
expresses viewpoints, contains information, affords adaptability
to new purpose, marks territory...
Examining the architecture of evolved buildings suggests a set
of attributes which could be expected of successful architecture
for any kind of modern system
Using Interpretive Structural Modelling, these various
objectives can be formed into an objectives "tree" or Attribute
Enhancement Structure
Kinds of Architecture
Appears in many forms, with decoration sometimes concealing
much underlying structure
Structure offers two main archetypes:-
Layered architectures, enabling or resisting passage
through a structure comprised of successive layers, perhaps
undergoing transformations, and finally exiting. This is the
basis of process oriented architectures used in manufacturing,
communications, defence and security, trees and plants, the
Sun, alimentry canal...
Clustered architectures, where architectural components
form into groups, perhaps with a view to reducing energy of, or
time taken for, interaction between the components. This is the
basis for architectures used in human organization, circuit
board and microcircuit design, some evolved biological
ÒdesignsÓ, topics in textbooks, parts stored a warehouses,
ethnic restaurants, books in a library...
In many systems, layers form as a result of clustering
Method used since pre-history is the layered defence:-
Instead of a single, eggs-in-one-basket, barrier, several
barriers in succession
Each layer need not be perfect
No single barrier responsible for all ÒneutralizationÓ
Attackers/intruders faced with time-consuming series of
hurdles
intruders exposed to detection/attack for longer, presenting
greater threat of detection
intruders must carry variety of tools/weapons/etc., to tackle
each (different?) layer of defence
Bona fide entrants less inconvenienced
in multi-layered system, each layer need not be so demanding
The figure shows a typical high security area, with fences,
sanitized zones, automatic cameras, even weapons (unusual in most
countries, but not unknown worldwide.)
There are some ten layers - note that a sanitized zone is a
layer, as well as a fence.
Layered Architecture and Mathematics
The simple equation adresses the probability of passing through a
series of N layers one after the other, each having the same
probability of neutralizing, i.e. of preventing further passage.
The equation produces the following graph:-
Looking at the graph, it soon becomes clear that the lines for
succesive layers are getting closer together. Evidently, there is
some law of diminishing returns at work.
If you have one layer, then a second gives a great benefit.
If you have 6 layers, then an extra layer confers much less
additional benefit.
The cost, in terms of effort, in adding each additional layer, may
soon prove prohibitive. Consider Maiden Castle:-
Counting earth ramparts, Maiden Castle had 5 layers of defence
Counting ditches between ramparts too, there were 11/12
Note at left and right ends, the additional earthworks
guarding the entrances - always a weak point
To a first approximation, the circumference of each ring goes up
as the square of its radius, so each successive ring going outwards
from the centre mus take significantly longer and cost more.
Add to that the diminishing return for each new ring, and it soon
becomes evident that there was a strong pressure to have the "right"
number of rings, where right means that the rings provided effective
defence at an affordable cost.
Systems architecture can be thought of as the organization and
grouping of things for some purpose. Architecture, then, is
servant to some higher purpose
Systems engineering architecture tends to afford the
foundations of performance, rather than aesthetics
Often, inter-change of substance or information between parts
within a system easier/uses less energy/faster, if distance
between parts is shorter.
Moving two parts closer to each other to improve inter-change
extends other links - hence some optimum arrangement improves
overall performance
That is systems architecture design - finding the
optimum for whole system, not just some parts
In going from the upper to lower diagrams, a degree of order
has been introduced - or, if you prefer, entropy (the measure of
disorder) has been reduced.
The entropy reduction is real. In the two figures, the sum of
all the link-lengths joining the entities is greatly reduced in
going from first to second figure. This shortening equates to
untangling, hence to real entropy reduction.
For clustering, consider:-
The value derived from clustering depends on the nature of the
system whose parts are clustered.
Where there is advantage to the overall system from reduced
time or energy utilization in the interchanges between internal
parts through internal infrastructure, then advantage may accrue
from reduced overall link-length. This condition pertains for many
systems but not for all
Advantage may also accrue from proximity between some parts of
one system and interacting parts of another system. In such cases
there may be a trade-off between internal advantage and overall
advantage
e.g. Analysis of aircraft under ground control shows that
control reliability would improve if aircraft and controller were
co-located. This is impractical. Hence an alternative strategy
emerges&endash;the provision of high-integrity, redundant
communication channels between aircraft and controller
From the N2 chart, note the following:-
There are two functionally bound blocks, one for airspace
control and one for ground movement control
There are three connected control centres.
The approach and takeoff control is at the centre of a "cross"
of interfaces, showing it to be a vital node - if it were not
there, the system would separate into pieces
All parts are connected, but only via one of the three
controls
