ZeePedia buy college essays online


Information Systems

<<< Previous Symbols used for flow charts: Good Practices, Data Flow Diagram Next >>>
 
img
VU
Information System (CS507)
LESSON 24
Symbols used for flow charts
24.1 Symbols
The symbols have already been briefly stated in the previous Lesson. Following would explain these
symbols in detail.
Arrow
The symbol indicates the flow of the
procedure being explained. The
usual direction of the flow of a
procedure or system is from left to
right or top to bottom.
Terminator
·This is the symbol used to indicate
the start and finish of the process.
·Only one flow line is used in
conjunction with terminator symbol.
100
img
VU
Information System (CS507)
Process
· This symbol is used to indicate a
activity undertaken or action done.
· For instance
Make sub-totals
Create file
· Only one flow line should come
out from a process symbol.
Decision
·The symbol is used when a choice can
be made between the options available.
·Such options are mutually exclusive.
·Only one flow line should enter a
decision symbol, but two or three flow
lines, one for each possible answer,
should leave the decision symbol.
<0
<0
=0
>0
<0
101
img
VU
Information System (CS507)
Connectors
·If the flowchart becomes complex,
it is better to use connector symbols
to reduce the number of flow lines.
·Avoid the intersection of flow lines
if you want to make it more effective
and better way of communication.
Predefined Process
·Where two or more steps are
repeated in a standard sequence,
they collectively are presented
through this symbol.
·This represents a named process
consisting of more than a couple of
operations or steps which must
have been identified separately.
102
img
VU
Information System (CS507)
Single Document
Refers to a hard copy being created
as a result of a process.
Off-Page Connector
Use to connect remote flowchart
portions on different pages. Only one
flow line enters or exits.
Input / Output Operation
· The symbol is used whenever the system
receives an input or generates an output..
E.g.
Display message
"How many
Read Hours
hours did you
work?"
Output Operation
Input Operation
· A single flow line enters and a single line
exits.
24.2 Good Practices
Recommended practices for flow charts:
·
Ensure that the flowchart has a logical start and finish.
103
img
VU
Information System (CS507)
·
In drawing a proper flowchart, all necessary steps that are a part of process should be listed out
in logical order.
·
The flowchart should be clear, neat and easy to follow. There should not be any room for
ambiguity in understanding the flowchart.
·
It is useful to test the validity of the flowchart.
Following can be seen as a comprehensive example of how the symbols of flow charts as defined above are
used.
As shown in the above diagram, the bidding process starts with issuing prequalification document. The
purpose is to seek preliminary information so as to decide whether the bidder qualifies for submitting a
bid. Where the information does not support the criteria, the bidder is not further allowed to proceed.
Other wise, the Request for Proposal is issued to the bidder.
Since the process cannot be summarized in one page, it is continued to the next page by using an off page
connector.
104
img
VU
Information System (CS507)
P#1
Off-Page Connector
RFP Document
Document
Used for Input / Output
Receive RFP
Evaluate on following basis
Process
1. Technical
2. Financial
Decision
Process
Intimate
Are the
N
unsuccessful
Terminator
End
criteria met
bidders
Y
Award
Process
Contract
End
Start/End of a process known as Terminator
On the next page, another off page connector is used to give reference of the page from which it is being
continued. The process continues with issuance of RFP document and receiving the filled RFP
document. An evaluation is made of the bidders on technical and financial bases. In case the criteria are
not met, the unsuccessful bidders are intimated and process for this class ends. Where the criteria are
met, contract is awarded. The process termination is shown by using the terminator symbol.
Advantages
·
The benefits of flowcharts are as follows:
·
Communication ­ Flowcharts are better way of communicating the logic of a system to all
concerned. Flowcharts are more focused on decision making and activities relating thereto taken in
a set of relevant processes.
·
Proper documentation ­ Program flowcharts serve as a good program documentation, which is
needed for various purposes.
Advantages
·
Efficient Coding: The flowcharts act as a guide or blueprint during the systems analysis and
program development phase.
·
Proper Debugging: The flowchart helps in locating and correcting errors (Also called
debugging).
·
Efficient Program Maintenance: The maintenance of operating program becomes easy with
the help of flowchart.
24.3 Data Flow Diagram
"A data flow diagram (DFD) is a graphical representation of the "flow" of data through an
105
img
VU
Information System (CS507)
information system."
The purpose of data flow diagrams is to provide a linking bridge between users and systems developers.
The data flow diagrams are:
·
Graphical, eliminating thousands of words;
·
Hierarchical, showing systems at any level of detail; and
They have less jargon, allowing user understanding and reviewing.
Data flow diagrams facilitate users to understand how the system operate. DFD's also help developers to
better understand the system which helps in avoiding delays in proper designing, development, etc. of
projects.
Following are the symbols of used in the making of flow charts.
Entity
represents sources of data received
by the system or destinations of the
data produced by the system.
E.g.
Customers, suppliers, purchase
department
If the entity is repeated in the DFD, the
same symbol with the addition of a bar in
the left hand corner is used and looks like.
106
img
VU
Information System (CS507)
Process
represents an activity that
transforms or manipulates the data
(combines, reorders, converts, etc.)
E.G
Calculate
Calculate Tax
Gross Salary
Deductions
Data Flow
represents movement of data
Data Store
Represents the permanent or temporary
data storage site. E.g.
Employee Master File
If this storage site is repeated in the DFD,
the same symbol with the addition of a bar
in the left hand corner is used and looks
like.
Employee Master File
107
Table of Contents:
  1. Need for information, Sources of Information: Primary, Secondary, Tertiary Sources
  2. Data vs. Information, Information Quality Checklist
  3. Size of the Organization and Information Requirements
  4. Hierarchical organization, Organizational Structure, Culture of the Organization
  5. Elements of Environment: Legal, Economic, Social, Technological, Corporate social responsibility, Ethics
  6. Manual Vs Computerised Information Systems, Emerging Digital Firms
  7. Open-Loop System, Closed Loop System, Open Systems, Closed Systems, Level of Planning
  8. Components of a system, Types of Systems, Attributes of an IS/CBIS
  9. Infrastructure: Transaction Processing System, Management Information System
  10. Support Systems: Office Automation Systems, Decision Support Systems, Types of DSS
  11. Data Mart: Online Analytical Processing (OLAP), Types of Models Used in DSS
  12. Organizational Information Systems, Marketing Information Systems, Key CRM Tasks
  13. Manufacturing Information System, Inventory Sub System, Production Sub System, Quality Sub system
  14. Accounting & Financial Information Systems, Human Resource Information Systems
  15. Decision Making: Types of Problems, Type of Decisions
  16. Phases of decision-making: Intelligence Phase, Design Phase, Choice Phase, Implementation Phase
  17. Planning for System Development: Models Used for and Types of System Development Life-Cycle
  18. Project lifecycle vs. SDLC, Costs of Proposed System, Classic lifecycle Model
  19. Entity Relationship Diagram (ERD), Design of the information flow, data base, User Interface
  20. Incremental Model: Evaluation, Incremental vs. Iterative
  21. Spiral Model: Determine Objectives, Alternatives and Constraints, Prototyping
  22. System Analysis: Systems Analyst, System Design, Designing user interface
  23. System Analysis & Design Methods, Structured Analysis and Design, Flow Chart
  24. Symbols used for flow charts: Good Practices, Data Flow Diagram
  25. Rules for DFD’s: Entity Relationship Diagram
  26. Symbols: Object-Orientation, Object Oriented Analysis
  27. Object Oriented Analysis and Design: Object, Classes, Inheritance, Encapsulation, Polymorphism
  28. Critical Success Factors (CSF): CSF vs. Key Performance Indicator, Centralized vs. Distributed Processing
  29. Security of Information System: Security Issues, Objective, Scope, Policy, Program
  30. Threat Identification: Types of Threats, Control Analysis, Impact analysis, Occurrence of threat
  31. Control Adjustment: cost effective Security, Roles & Responsibility, Report Preparation
  32. Physical vs. Logical access, Viruses, Sources of Transmissions, Technical controls
  33. Antivirus software: Scanners, Active monitors, Behavior blockers, Logical intrusion, Best Password practices, Firewall
  34. Types of Controls: Access Controls, Cryptography, Biometrics
  35. Audit trails and logs: Audit trails and types of errors, IS audit, Parameters of IS audit
  36. Risk Management: Phases, focal Point, System Characterization, Vulnerability Assessment
  37. Control Analysis: Likelihood Determination, Impact Analysis, Risk Determination, Results Documentation
  38. Risk Management: Business Continuity Planning, Components, Phases of BCP, Business Impact Analysis (BIA)
  39. Web Security: Passive attacks, Active Attacks, Methods to avoid internet attacks
  40. Internet Security Controls, Firewall Security SystemsIntrusion Detection Systems, Components of IDS, Digital Certificates
  41. Commerce vs. E-Business, Business to Consumer (B2C), Electronic Data Interchange (EDI), E-Government
  42. Supply Chain Management: Integrating systems, Methods, Using SCM Software
  43. Using ERP Software, Evolution of ERP, Business Objectives and IT
  44. ERP & E-commerce, ERP & CRM, ERP– Ownership and sponsor ship
  45. Ethics in IS: Threats to Privacy, Electronic Surveillance, Data Profiling, TRIPS, Workplace Monitoring