InfoSys 3810
Week Three
2013
Systems Analysis
Dr. Vicki Sauter and Friends
Professor, Information Systems
University of Missouri Saint Louis
Last Week
Systems Analysis and Design
Five fundamental, separable, yet interrelated
elements
 Planning … including requirements elicitation
 Analysis
 Design (including logical design and physical design (
or preliminary design and detailed design)
 Implementation … which includes coding, test, and
deployment
 And
 Maintenance
Last Week
Systems Analysis and Design
The waterfall model … a sequential process
where one phase is completed before the
next is started …
There is significant formalism to this model
There is little actual use of this model in
today’s Information Systems world
The Waterfall model is just one systems
development methodology
Last Week
Systems Analysis … A Definition
Systems Analysis is an explicit formal inquiry carried
out to help someone identify a better course of action
and make a better decision than he might otherwise
have made.
identification and re-identification) of objectives,
constraints, and alternative courses of action
of the probable consequences of the
alternatives in terms of costs, benefits, and risks
presentation of the results in a comparative
framework so that the decision maker can make
an informed choice from among the alternatives
©
Principia Cybernetica Web
Last Week
Systems and Systems Analysis
Definition of a System
A system is composed of interacting parts that
operate together to achieve some objective or
purpose. a system is intended to "absorb"
inputs, process them in some way and
produce outputs (where outputs are defined by
goals, objectives or common purposes)
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Different perspectives
… for different needs
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Last Week
Zachman Framework, Cont
VA Enterprise
Architecture
DATA
What
FUNCTION
How
NETWORK
Where
PEOPLE
Who
TIME
When
MOTIVATION
Why
SCOPE
(CONTEXTUAL)
Things Im portant
to the Business
Processes
Performed
Business
locations
Important
Organiz ations
Ev ents Signific ant
to the Business
Business Goals
and Strategy
Planner
Entity = Class of
Business Thing
Function = Class of
Business Process
Node = Major
Business Locations
People = Major
Organiz ations
Time = Major
Business Event
Ends/Means =
Major Business Goals
ENTERPRISE
MODEL
(CONCEPTUAL)
Semantic Model
Business Process
Model
Business Logistic s
System
Work Flow Model
Master Schedule
Business Plan
Owner
Ent = Business Entity
Proc = Business Process Node = Business Location People = Organization Unit Time = Business Event
Rel = Business Relationship I/O = Business Resources Link = Business Linkage
Work = Work Product
Cycle = Business Cycle
End = Business Objectiv e
Means = Business Strategy
SYSTEM MODEL
(LOGICAL)
Logical Data
Model
Application
Architecture
Processing
Structure
Business Rule
Model
Designer
Ent = Data Entity
Rel = Data Relationship
Proc = Application Function Node = IS Function
People = Role
I/O = User Views
Link = Line Characteristic s Work = Deliv erable
Time = System Event
Cycle = Processing Cycle
End = Structural Assertion
Means = Action Assertion
TECHNOLOGY
MODEL
(PHYSICAL)
Physical Data
Model
System
Design
Control
Structure
Rule
Design
Builder
Ent = Segment/Table
Rel = Pointer/Key
Proc = Computer Function Node = Hardware/Softw are People = User
I/O = Data Elements /Sets Link = Line Specifications Work = Screen Format
Time = Ex ecute
End = Condition
Cycle = Component Cycle Means = Action
Program
Security
Architecture
Timing
Definition
Rule
Design
Data
DETAILED
REPRESENTATIONS Definition
(OUT-OF-CONTEXT)
Distributed System
Architecture
Technology
Architecture
Netw ork
Architecture
Human Interface
Architecture
Presentation
Architecture
Sub-Contractor
Ent = Field
Rel = Address
Proc = Language Statement Node = Addresses
I/O = Control Block
Link = Protocols
People = Identity
Work = Job
Time = Interrupt
Cycle = Machine Cycle
End = Sub-Condition
Means = Step
FUNCTIONING
ENTERPRISE
Data
Function
Netw ork
Organiz ation
Schedule
Strategy
Ent =
Rel =
Proc =
I/O =
Node =
Link =
People =
Work =
Time =
Cycle =
End =
Means =
DATA
What
FUNCTION
How
NETWORK
Where
© R.A. Navarro
PEOPLE
Who
TIME
When
MOTIVATION
Why
Based on work by
John A. Zachman
SCOPE
(CONTEXTUAL)
Planner
ENTERPRISE
MODEL
(CONCEPTUAL)
Owner
SYSTEM MODEL
(LOGICAL)
Designer
TECHNOLOGY
MODEL
(PHYSICAL)
Builder
DETAILED
REPRESENTATIONS
(OUT-OF-CONTEXT)
Sub-Contractor
FUNCTIONING
ENTERPRISE
Last Week
Business Rules
A business rule is a rule of a business, company, or
corporation. It is a rule that defines or constrains
some aspect of business and always resolves to
either true or false. Business rules are intended to
assert business structure or to control or influence
the behavior of the business. Business rules
describe the operations, definitions and constraints
that apply to an organization. Business rules can
apply to people, processes, corporate behavior and
computing systems in an organization, and are put in
place to help the organization achieve its goals.
Wikipedia.net
The Requirements Phase of Process
Development
Definition ( Wikipedia)
A requirement is a documented need of what a
particular system should be or do.
A requirement can be a description of
what a system must do. This type of
requirement specifies something that
the delivered system must be able to
do.
Other types of requirements specify
something about the system itself, and
how well it performs its functions.
© R.A. Navarro
11/42
Formal Requirements
Business Processes Design And
Development Must Be Based On Formal
Requirements
Functional requirements
Non-functional requirements
Pseudo requirements
© R.A. Navarro
12/42
Formal Requirements
Methodologies for Requirements Elicitation
 Archival document analysis
 Document review
 Inspiration / Imagineering
 Interviews
 Surveys or Questionnaires
 Delphi Method
 Direct Observation
 Contextual Inquiry
 Concept Elicitation
 Focus Groups
 RAD / JAD
 Prototyping
© R.A. Navarro
Individualoriented
methods
Grouporiented
methods
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Creativity
The Calf Path
One day thru the primeval wood
A calf walked home, as good calves should,
But made a trail all bent askew,
A crooked trail, as all calves do.
Since then three hundred years have fled,
And I infer, the calf is dead;
But still behind he left his trail,
And thereon hangs my mortal tale.
The trail was taken up next day
By a lone dog that passed that way,
And then a wise bell-weather sheep
Sliding into a rut now deep,
Pursued that trail over hill and glade
Thru those old woods a path was made.
The Calf Path
And many men wound in and out,
And dodged and turned and bent about,
and uttered words of righteous wrath
Because “twas such a crooked path”
But still they follow-do not laughThe first migrations of that calf.
The forest became a lane
That bent and turned and turned again;
This crooked lane became a road
where many a poor horse with his load
Toiled on beneath the burning sun,
And traveled some three miles in one.
The Calf Path
The years passed on in swiftness fleet,
The village road became a street,
And this, before the men were aware,
A city’s crowded thoroughfare.
And soon a central street was this
In a renowned metropolis;
And men two centuries and a half
Followed the wanderings of this calf.
Each day a hundred thousand strong
Followed this zigzag calf along;
And over his crooked journey went
The traffic of a continent.
The Calf Path
A hundred thousand men were led
By one poor calf, three centuries dead.
For just such reverence is lent
To well established precedent.
A moral lesson this might teach
Were I ordained and called to preach.
For men are prone to go it blind
Along the calf paths of the mind;
And work away from sun to sun
To do what other men have done.
Sam Walter Foss
Class Discussion
Class Exercise
Re: The UMSL Library System
 You have all researched the UMSL
Library Business Rules
 You all understand the function of a library
from a student’s point of view
 Develop an Improved set of business
rules
Be Creative
Notes
Networking Expectations are defined on the
class website
There is a networking opportunity tomorrow
morning …
Breakfast and Business
7:30 am in the MSC
Featuring Juli Niemann … “What
Recovery”
Systems analysis
There are two fundamentally different ways
of approaching systems analysis
Process View
Data View
Systems Analysis … Processes vs Data
Points of View
Systems Analysis … The Process View
A Process is defined as
A sequence of related tasks which combine to
accomplish a function
A transformation
Systems Analysis … The Process View
A system may be “modeled” using a process
documentation formalism
A language
A representation Schema
Typical among such schema
Visio
IBM Flow-Charting Templates
IDEF
Systems Analysis … Data View
Data are values of qualitative or quantitative
variables
Data in are typically represented in a
structure, often tabular, a tree, or a graph
structure.
Data are typically the results of
measurements
Data as an abstract concept can be viewed as
the lowest level of abstraction from which
information and then knowledge are derived
Systems Analysis … Data View
Wisdom
Knowledge
Information
Data
Systems Analysis … Data View
Systems Analysis … Data View
DFD’s show
Input to and output from the system across
the system boundary
Inputs and outputs to and from system
elements
Flow among systems elements
Storages
DFD’s do NOT show timing, control etc.
Class Exercise
Working in groups:
Define the data necessary to support a
system developed to meet YOUR new
library business rules