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Unit 1. What Is A System?
11
verb
noun
adjective
reliable
accomplish
dependable
sustainable
survive
GRAMMAR FOCUS
Before reading the text, revise the grammar material (§1 THE PASSIVE
VOICE, p.132) and do the exercises.
11. Underline the correct form of the verb and translate the sentences
into Russian.
1. Our next discussions shift to understanding how systems and their op-
erating environments are/was organized and structured.
2. The component parts of a system can best be/are understood in the context
of relationships with each other and with other systems, rather than in isolation.
3. Complex wholes are/has been made up of smaller subsystems.
4. Significant development to the concept of a system was/will be done by
Norbert Wiener and Ross Ashby who pioneered the use of mathematics to study
systems.
5. Man-made systems are/be made with purposes that are achieved by the
delivery of outputs.
6. There are many types of systems that can be/were analyzed both quan-
titatively and qualitatively.
7. Important distinctions have been/had been made between hard and soft
systems.
8. The economic system is/have been composed of people, institutions and
their relationships to resources, such as the convention of property.
9. In engineering and physics, a physical system is the portion of the uni-
verse that is being/has been studied (of which a thermodynamic system is one
major example).
10. In the 1940s and 1950s the systems view was/is based on several fun-
damental ideas.
11. All phenomena can be/was viewed as a web of relationships among el-
ements, or a system.
System analyses and control
12
12. The terms "systems theory" and "cybernetics" have been/has been
widely used as synonyms.
13. In recent years, systems thinking has been/was developed to provide
techniques for studying systems.
14. Systems engineering is an interdisciplinary field of engineering that fo-
cuses on how complex engineering projects should be/were designed and managed.
15. A cultural system may has been/be defined as the interaction of different
elements of culture.
12. Rewrite these sentences in the Passive Voice.
1. They understand dynamic systems as open, complex systems, with the
capacity to evolve over time.
2. They coined the term complex adaptive systems at the interdisciplinary
Santa Fe Institute (SFI).
3. In this more recent tradition, some consider systems theory in organiza-
tional studies as a humanistic extension of the natural sciences.
4. Scientists has also developed Systems theory within sociology.
5. Representatives from a number of US corporations and organizations
founded a professional society for systems engineering, the National Council on
Systems Engineering (NCOSE) in 1990.
6. They use such systems to model processes in computer science, biology,
economics, physics, and many other fields.
7. They study a variety of abstract theoretical complex systems as a field
of mathematics.
13. Scan the text and write out sentences with verbs in the passive
voice. Translate them.
SPECIALIST READING
TEXT A
WHAT IS A SYSTEM?
14. Scan the text and write out definitions for these words:
system –
environment –
boundary –
Unit 1. What Is A System?
13
15. Read the text and put the points of the plan in the right order
according to the main content of the text:
system definition rationale
symbolic representation of a system
types of systems
definition of a system
The term “system” originates from the Greek term systЇema, which means
to “place together.” This text defines a system as an integrated set of interopera-
ble elements, each with explicitly specified and bounded capabilities, working
synergistically to perform value-added processing to enable a User to satisfy mission-oriented operational needs in a prescribed operating environment with a
specified outcome and probability of success. The definition above captures a
number of key discussion points about systems. To help you understand the rationale for this definition, let us examine each part in detail.
By “an integrated set,” we mean that a system, is composed of hierarchical
levels of physical elements, entities, or components.
By “interoperable elements,” we mean that elements within the system’s
structure must be compatible with each other in form, fit, and function. System
elements include equipment, maintenance, supplies, spares, training, resources,
procedural data, external systems, and anything else that supports mission accomplishment.
By each element having “explicitly specified and bounded capabilities,” we
mean that every element should work to accomplish some higher level goal. System element contributions to the overall system performance must be explicitly
specified. This requires that operational and functional performance capabilities for
each system element be identified and bounded to a level of specificity that allows
the element to be analyzed, designed, developed, tested, verified, and validated.
By “working in synergistically,” we mean that the purpose of integrating
the set of elements is to leverage the capabilities of individual element capabilities to accomplish a higher level capability that cannot be achieved as stand-alone
elements.
By “value-added processing,” we mean that factors such operational cost,
utility, suitability, availability, and efficiency demand that each system operation
and task add value to its inputs availability and produce outputs that contribute to
achievement of the overall system mission outcome and performance objectives.
System analyses and control
14
By “enable a user to predictably satisfy mission-oriented operational
needs,” we mean that every system has a purpose (i.e., a reason for existence)
and a value to the user(s). Its value may be a return on investment (ROI) relative
to satisfying operational needs or to satisfy system missions and objectives.
By “in a prescribed operating environment,” we mean that for economic,
outcome, and survival reasons, every system must have a prescribed – that is,
bounded – operating environment.
By “with a specified outcome,” we mean that system stakeholders ex-
pect systems to produce results. The observed behavior, products, byproducts,
or services, for example, must be outcome-oriented, quantifiable, measurable,
and verifiable.
By “and probability of success,” we mean that accomplishment of a spe-
cific outcome involves a degree of uncertainty or risk. Thus, the degree of success is determined by various performance factors such as reliability, dependability, availability, maintainability, sustainability, lethality, and survivability.
Systems occur in a number of forms and vary in composition, hierarchical
structure, and behavior. Consider the next high-level examples: Economic, Educational, Financial, Transportation, Communications, Entertainment, Environmental, Medical, Cultural, Psychological, Food distribution.
If we analyze these systems, we find that they produce combinations of
products, by-products, or services. Further analysis reveals most of these fall into
one or more classes such as individual versus organizational; formal versus informal; ground-based, sea-based, air-based, space-based, or hybrid; human-inthe-loop (HITL) systems, open loop versus closed loop; and fixed, mobile, and
transportable systems.
As an abstraction we symbolically represent a system as a simple entity
by using a rectangular box as shown in Figure 1. In general, inputs such as stimuli and cues are fed into a system that processes the inputs and produces an output. Outputs are defined by goals, objectives or common purposes.
In order to understand the relationship between inputs, outputs and processes, you need to understand the environment in which all of this occurs.
The environment represents everything that is important to understanding
the functioning of the system, but is not part of the system. The environment it
is that part of the world that can be ignored in the analysis except for its interaction with the system.
Unit 1. What Is A System?
15
Figure 1.
The boundary defines the difference between the environment and the sys-
tem; the correct boundary is a function of the problem under consideration [1].
VOCABULARY IN USE
16. Match to make word combinations.
1. satisfy
2. accomplish
3. add
4. produce
5. represent
6. process
7. have
8. leverage
9. support
1. a goal
2. capabilities
3. value
4. needs
5. outputs
6. a purpose
7. inputs
8. accomplishment
9. a system
17. Replace the italicized words with the equivalents from the box.
elements, environment, capabilities, satisfy, bounded
1. The boundary defines the difference between the surroundings and the
system.
System analyses and control
16
2. Constituent parts within the system’s structure must be compatible with
each other in form, fit, and function.
3. Every element should work to accomplish some higher level goal.
4. Every system must have a prescribed operating environment.
5. The purpose of integrating the set of elements is to leverage the poten-
tial of an individual element.
COMPREHENSION CHECK
18. Answer the questions.
1. What do system elements include?
2. What does every element should work for?
3. What is the purpose of integrating the set of elements?
4. What do system stakeholders expect systems to produce?
5. What is the degree of success determined by?
6. What do systems produce?
7. What are some examples of types of systems?
19. Decide whether the following statements are true or false (T/F) by
referring to the information in the text. Then make the necessary changes
so that the false statements become true.
1. Elements within the system’s structure must be compatible with each
other in form, fit, and function.
2. Every system has a purpose and a value to the user(s).
3. A system is composed of hierarchical levels of physical elements.
4. Every system must have a prescribed operating environment.
5. The boundary defines the difference between system elements.
6. The system processes the outputs and produces an input.
7. The environment is a part of the system.
WEB QUEST
National and international standards organizations as well as different authors have their own definitions of a system. If you analyze these, you will find
a diversity of viewpoints, all tempered by their personal knowledge and experiences. Moreover, achievement of a “one size fits all” convergence and consensus
by standards organizations often results in wording that is so diluted that many
Unit 1. What Is A System?
17
believe it to be insufficient and inadequate. You are encouraged to broaden your
knowledge and explore different definitions.
20. Visit sites given below and complete the chat.
Compare and contrast these definitions and determine which one best fits
your beliefs and experiences?
Web adress
Name of the or-
ganization, au-
thor or dictionary
Definition
http://www.freetutes.com/ systemanalysis/SA001_1.htm
Charles S.
Wasson
The term “system” originates from the Greek
term systЇema, which
means to “place together.” This text defines
a system as an integrated
set of interoperable elements, each with explicitly specified and
bounded capabilities,
working synergistically
to perform value-added
processing to enable a
User to satisfy missionoriented operational
needs in a prescribed operating environment with
a specified outcome and
probability of success.
http://www.umsl.edu/~sauterv/analysis/bees/index.html
http://www.umsl.edu/~sauterv/analysis/intro/system.htm
http://www.businessdictionary.com/definition/system.html
http://www.its.bldrdoc.gov/fs1037/dir-036/_5255.htm
http://en.wikipedia.org/wiki/System
System analyses and control
18
Web adress
Name of the or-
ganization, au-
thor or dictionary
Definition
http://pespmc1.vub.ac.be/ASC/SYSTEM.html
http://en.wikipedia.org/wiki/System_engineering
ANSI/EIA-6321999
IEEE Std 12201998
ISO/IEC
15288:2008
NASA
INCOSE Systems Engineering
Handbook
INCOSE
http://en.wikipedia.org/wiki/Portal:Systems_science
TEXT B
TYPES OF SYSTEMS
21. Read the text, make up a plan of the main content and write out
key words for every point of your plan.
points
key words
In the context of the physical world, a system is a set of physically related
items that we set apart in our mind from the environment surrounding them. A
system can be something as innocuous as an ice cube floating in a glass of water,
or as complex as the Earth, and all that resides on it, floating through space. What
the system of interest is, and how its boundaries are defined, depends upon the
particular circumstances driving the consideration. For instance, going back to
the ice cube floating in the glass of water, if we are interested in just the properties of the ice cube, then it is the system. The glass of water and surrounding air
are its environment. If we are interested in whether or not we have a cool glass
Unit 1. What Is A System?
19
of water to drink, then the glass of water, including the ice cube, becomes the
system; and, the surrounding air, and whatever is holding the glass, become its
environment.
There are various types of system. To have a good understanding of
these systems, these can be categorized in many ways. Some of the categories
are open closed or isolated, physical or abstract and natural or man-made information systems.
Open, Closed or Isolated Systems
Systems interact with their environment to achieve their targets. Things
that are not part of the system are environmental elements for the system. Depending upon the interaction with the environment, systems can be classified as
open, closed or isolated. Open systems allow energy and matter to pass across
the system boundary. Practically most of the systems are open systems. An open
system has many interfaces with its environment. It can also adapt to changing
environmental conditions. It can receive inputs from, and delivers output to the
outside of system. An information system is an example of this category. The ice
cube floating in the glass of water is an open system both energy and matter can
flow freely between the ice cube and the surrounding water, which enables the
ice cube to melt.
In a closed system, only energy can flow freely between the system and
its environment. The Earth is often viewed as a closed system. Energy from the
sun reaches the Earth's surface, and the Earth radiates much of its heat into space.
But, the atmosphere and material on the Earth's surface is held in place by the
Earth's gravity. It does not flow freely into space.
The contents of a pressure cooker on a stove with its lid tightly closed and
the whistle in position, is a closed system as no mass can enter or leave the pressure cooker, but heat can be transferred to it. When the whistle of the pressure
cooker blows, then it becomes an open system as steam leaves the cooker. A
perfectly insulated, rigid and closed vessel is an example of an isolated system
as neither mass nor energy can enter or leave the system. The universe is an isolated system.
In an isolated system, neither energy nor matter flow freely between the
system and its environment. Perfectly isolated systems do not really exist in nature, but we frequently depend upon devices that approximate isolated systems.
For instance, we rely on coolers to keep our picnic drinks cold (hopefully there
System analyses and control
20
is minimal transfer of energy and matter between the environment and the
cooler – at least until we decide to open it).
Systems and surroundings have many practical applications in our own
day-to-day lives. Without even knowing, we interact with thousands of closed
and open systems every day. For example, when packing lunch, food is normally
placed in some sort of closed container (so that things don't enter or leave the
container). Anything can be defined as a system, and everything else would then
be the surroundings.
In reality, the type of system one is dealing with has many implications.
Furthermore, based on systems and surroundings, scientists have come up with
a couple of laws known as laws of thermodynamics. The first and second law of
thermodynamics briefly stated are:
1) The internal energy of an isolated system stays constant.
2) The entropy of an isolated system tends to increase.
The first law is based upon the definition of an isolated system. An isolated system by definition, is a system that does not allow energy transfer. Thus,
it makes sense to say that the internal energy of an isolated system stays constant
because it does not change at all.
The second law of thermodynamics, increasing entropy of an isolated system, asks for basic understanding of entropy. Entropy is the disorder within a
system. For example, a solid has no disorder (atoms are packed into a cube and
cannot move) whereas a gas has more disorder (atoms bouncing all over the
place). Thus, this law states that the entropy of an isolated system tends to increase (i.e. a chemical reaction taking place in an isolated system will never have
a liquid becoming a solid because that is a decrease in entropy) [1].
22. Answer these questions. Explain your answers.
1) Which type of thermodynamic system is an ocean? an aquarium? a
pizza delivery bag? a greenhouse?
2) A closed system contains 2g of ice. 2 more g of ice are added to the
system. What is the final mass of the system?
3) An isolated system has an initial temperature of 30°C. It is then placed
on top of a Bunsen burner for an hour. What is the final temperature?
4) What do the first and second laws of thermodynamics have to do with
systems?
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