INTRODUCTION TO INFORMATION SYSTEMS
The term “system” originates from the
Greek term systema, which means to “place together.” Multiple business and
engineering domains have definitions of a system. This text defines a system
as: System
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 mission-oriented operational needs in a prescribed
operating environment with a specified outcome and probability of success.
1.1 SYSTEM DEFINITION RATIONALE
The definition above captures a
number of key discussion points about systems.
·
By
“an integrated set,” means that a
system, by definition, 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,
·
By
each element having “explicitly specified
and bounded capabilities,” means that every element should work to
accomplish some higher level goal or purposeful mission. 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 explicitly bounded to a level of specificity
that allows the element to be analyzed, designed, developed, tested, verified,
and validated—either on a stand-alone basis or as part of the integrated
system.
·
By
“working in synergistically,” means
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,” means 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.
·
By
“enable a user to predictably satisfy
mission-oriented operational needs,” means 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,” means
that for economic, outcome, and survival reasons, every system must have a
prescribed—that is, bounded—operating environment.
·
By
“with a specified outcome,” means
that system stakeholders (Users, shareholders, owners, etc.) expect 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,” means
that accomplishment of a specific 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.
1.2 SYSTEM REDEFINED
A system is an ordered grouping of independent components linked
together according to specifications so as to achieve defined objectives of a
business organization.
A system in its broadest
form is a group of components that interact to achieve a purpose. Comprises
elements namely people, resources, concepts and procedures intended to perform
a function towards a goal
The study of systems concepts has the following
implications:-
·
A
system is designed to achieve a predetermined objective
·
Interrelationships
and interdependences exist among the components
·
Objectives
of an org. have higher priority than objectives of its sub-systems
A system can assume one of the forms
Schematic
system – a two dimensional representation
Flow
system – an abstraction of real world e.g. PERT chart
Static
system – exhibits one relationship e.g. GANNT charts
Dynamic
system – model that approximates the business organization
1.3 SYSTEMS AND
ORGARNIZATION
·
Organizations
are complex systems that consist of inter-related and interlocking subsystems
such that changes in one subsystem has anticipated consequences in other parts
of the systems.
·
Systems
analysis concerns the application of the system approach to the study and
finding solution of problems using computer-based systems.
·
System
analysis provides a framework for visualizing the organizational and
environment factors that operate on system.
·
Computerizing
operations of an org improves performance, efficiency, effectiveness,
satisfaction, quality information processing and results.
However automating operation has negative impact such as
·
Possible
threat to employment due to redundancy
·
Decreased
morale of personnel who were not consulted about the installation
·
Feeling
of intimidation by users who have limited training in Computer skills
1.3.1 SYSTEMS THEORY
·
The
systems theory is concerned with tendency towards the fragmentation of
knowledge and the increasing complexity of the organizations
·
Systems
concepts relate to the organizations by viewing an ongoing system / operations
as a processor of information for making decisions, in which information and
communication provide connecting links for unifying various components
·
Generally,
systems theory is concerned with developing a systematic, theoretical framework
upon which to make decisions by considering all activities of the org. and its
external environment
1.3.2 COMPONENTS OF A
SYSTEM
A system has distinct components namely
- Inputs –elements that enter the system
e.g. data entered into comp. raw materials to a plant,
- Processes – operations necessary to
convert / transform inputs to outputs. Computer processing involves activating
commands, execution, computations and storage
- Control – elements that guide the system in decision making by monitoring
pattern of activities that govern
input, processing and output e.g. OS, management etc
- Outputs – Describes finished products /
services as consequences of inputs being in the system
- Communication - Also feed-forward and feedback which are Connections / flow of info
and materials among sub-systems. Reports on Operations & performance
of systems for decision – making modification of inputs/process
- Boundary – Physical/non-physical confinement
that separates a system from its environment
- Environment – Comprises elements outside a
system that can impact on a system’s performance e.g. Business environ
includes competitors, suppliers, customers, regulation agencies,
demographic, social & economic conditions
1.3.3 CHARACTERISTICS
OF A SYSTEM
- Organization – implies structure and order of arrangement of the
components that help to achieve the objectives. A business system has a
defined authority structure, specifies the formal flow of communication
and formalizes the chain of command; whose info. Is processed by an IS
- Interaction – concerns the functions of systems’ components set to
realize efficient and effective performance
- Interdependence – parts of org. or computer system depend on one
another but are linked together and coordinated to a plan, whereby the
output of one sub system may be an input of another, all aimed at proper
functioning
- Integration – concerned with how parts of a system work together
within the system even though each part performs a unique function
- Common objective – users to know the main objective of a computer
application during analysis for a successful design and conversion
1.4 SYSTEM FEATURES
A big system may be seen as a set of
interacting smaller systems known as subsystems or functional units each of
which have its defined tasks. All these work in coordination to achieve the
overall objective of the system. System engineering requires development of a
strong foundation in understanding how to characterize a system, product, or
service in terms of its attributes, properties, and performance. As discussed
above, a system is a set of components working together to achieve some goal. Systems also exhibit certain features and characteristics,
some of which are:
1.4.1 OBJECTIVES
Every system has a predefined goal or
objective towards which it works. A system cannot exist without a defined
objective. For example an organization would have an objective of earning
maximum possible revenues, for which each department and each individual has to
work in coordination.
1.4.2 STANDARDS
It is the acceptable level of
performance for any system. Systems should be designed to meet standards.
Standards can be business specific or organization specific. For example take a
sorting problem. There are various sorting algorithms. But each has its own complexity
so that such algorithm should be used that gives most optimum efficiency. So
there should be a standard or rule to use a particular algorithm. It should be
seen whether that algorithm is implemented in the system.
1.4.3 ENVIRONMENT
Every system whether it is natural or
manmade co-exists with an environment. It is very important for a system to
adapt itself to its environment. Also, for a system to exist it should change
according to the changing environment.
1.4.4 FEED BACK
Feedback is an important element of
systems. The output of a system needs to be observed and feedback from the
output taken so as to improve the system and make it achieve the laid
standards. A system takes input. It then transforms it into output. Also some
feedback can come from customer (regarding quality) or it can be some
intermediate data (the output of one process and input for the other) that is
required to produce final output.
1.4.5 BOUNDARIES AND
INTERFACES
Every system has defined boundaries
within which it operates. Beyond these limits the system has to interact with
the other systems. For instance, Personnel system in an organization has its
work domain with defined procedures. If the financial details of an employee
are required, the system has to interact with the Accounting system to get the
required details. Interfaces are another important element through which the
system interacts with the outside world. System interacts with other systems
through its interfaces. Users of the systems also interact with it through
interfaces. Therefore, these should be customized to the user needs. These
should be as user friendly as possible.
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