The Architecture of Systems

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13 Δεκ 2013 (πριν από 3 χρόνια και 5 μήνες)

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The Architecture of Systems

System Architecture

Every human
-
made and natural system is
characterized by a
structure and framework
that supports and/or enables the
integrated
elements
of the system to
provide the
system’s capabilities
and perform missions.
This integrated framework is referred to as
the system’s architecture.

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Architecture via a Construct

Let us introduce the concept of the
system element

architecture via a construct
consisting of two key

entities:

1)
the SYSTEM OF INTEREST (SOI)

2)
its OPERATING ENVIRONMENT.

The SOI is composed of one or more MISSION

SYSTEM(s) (role) and a SUPPORT SYSTEM (role).


The OPERATING ENVIRONMENT consists of:


1)
HIGHER ORDER SYSTEMS domain

2)
A PHYSICAL ENVIRONMENT domain.

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THE SYSTEM ARCHITECTURE
CONSTRUCT

All natural and human
-
made systems exist within an

abstraction we refer to as the system’s OPERATING

ENVIRONMENT.


Survival, for many systems within the OPERATING

ENVIRONMENT, ultimately depends on system

capabilities

physical properties, characteristics,

strategies, tactics, security, timing, and luck.


The systems exhibit a common construct

template


that describes a system’s relationship to their

OPERATING ENVIRONMENT.

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Top Level System Architecture Construct


When you analyze interactions of a SYSTEM OF INTEREST (SOI)
with its OPERATING ENVIRONMENT, two fundamental types of
behavior emerge:

1. Hierarchical
interactions (i.e., vertical interactions under the
command and control of higher order systems)
.

2. Peer level interactions.

System Elements

Important for three reasons:


First, the system elements enable us
to organize,

classify, and bound system entity abstractions and their

interactions. That is, it is a way to differentiate
what is

and what is not included in the system.


Second, the System Element Architecture
establishes a

common framework for developing the
logical and physical

system architectures

of each entity within the system

hierarchy.


Third, the system elements serve as an initial starting

point for allocations of multi
-
level performance

specification requirements.

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Identification of system element classes
by domain


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Top Level System Environment Construct

When a MISSION SYSTEM interacts with its OPERATING
ENVIRONMENT, it:

1. Performs mission task assignments established by higher level,
chain
-
of
-
command, decision authorities.

2. Interacts with
external systems (i.e., human
-
made systems, natural
environment, and its
induced operating environment during mission
execution environment).

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THE SYSTEM ARCHITECTURE
CONSTRUCT

When systems interact with their OPERATING

ENVIRONMENT, two types of behavior patterns emerge:

1. Systems interact with or respond to the dynamics
in their OPERATING ENVIRONMENT.

These interactions reflect peer
-
to
-
peer role
-
based

behavioral patterns such as
aggressor, predator, and

defender or combinations of these.

2. System Responses

behavior, products, by
-
products, or
services

and internal failures sometime result in
adverse
or catastrophic effects to the system

creating instability,


damage, degraded performance, for example

that may
place the system’s mission or survival at risk.

Challenge in analyzing

The challenge in analyzing and solving system development

and engineering problems is being able to
identify,

organize, define, and articulate the relevant elements of a

problem (objectives,
initial conditions, assumptions, etc.) in

an easy
-
to
-
understand, intelligible manner that enables us

to
conceptualize and formulate the solution strategy.


Establishing a standard analytical framework
enables us to

apply “plug and chug” mathematical and scientific

principles, the core strength of engineering training, to the

architecture of the system.

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UNDERSTANDING SYSTEM ELEMENT

ENTITY RELATIONSHIPS


System element
interactions can be characterized by

two types of relationships:


Logical

physical


Perhaps the best way to think of logical and physical

relationships is to focus on one topic
at a time and

then integrate the two concepts.

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Identifying Logical Entity
Relationships

The
first step in identifying logical entity relationships is to

simply recognize and acknowledge that

some form of

association exists through deductive reasoning.


Graphically, we depict these relationships as simply a line

between the two entities.


The
second step is to characterize the logical relationship

in terms of logical functions


that is,
what interaction

occurs between them

must be provided to enable the two

entities to
associate with one another as
logical

architecture.

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Logical Association Example:
Light Source

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Physical Entity Relationships



The physical implementation of system element interfaces

requires more in
-
depth analysis and decision making.

Why?


Typically, cost, schedule, technology, support, and risk

become key drivers that
must be “in balance” for the actual

implementation.


Graphically, the
physical
Implementation as a
physical

representation.


As we select components (copper wire, light switches,

lighting fixtures, etc.), we configure them into a system block

diagram (SBD) and electrical schematics that depict the

physical relationships.


These diagrams become the basis for the
Physical System

Architecture.

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Physical Representation

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