Transcript Public Management Information Systems System Analysis & Design Ph.D.

Public Management Information Systems
System Analysis & Design
Friday, May 20, 2016
Hun Myoung Park, Ph.D.
Public Management & Policy Analysis Program
Graduate School of International Relations
System Development Life Cycle
1.
2.
3.
4.
5.
6.
Investigation (planning)
Systems analysis
Systems design
System development
Systems implementation
System maintenance
2
Why SDLC?
•
•
•
Systematic approach to give guidelines for
improving efficiency and effectiveness
To avoid system failures: lack of
communication (acceptance); politics (sunk
costs) and leaderships; technical
incompetence; education & training
Considered as conceptual model and
depending on institutional settings.
3
Caution in SDLC
•
•
•
•
Programming is a part of system development
Phases (steps) may not always be distinct and
thus may overlap
Phases are interrelated and interdependence
Detecting errors in an early phase will save the
cost
4
Prototyping
• Iterative approach to revise prototypes.
• “During each iteration, requirements and
alternative solutions to the problem are identified
and analyze, new solutions are designed, …” (p.
507)
• “[A]n iterative process involving analysts and
users whereby a rudimentary version of an
information system is built and rebuilt according
to user feedback.” (p.195)
5
6
Other Approaches
•
•
•
•
Rapid application development (RAD)
Agile (usage-centered) development
Extreme programming (XP)
Adaptive software development, lean
software development, rational unified
process, feature-driven development
• Customization, fast cycles, error-correction
7
Step 1. Investigation
•
•
•
•
•
Determine organization’s objectives
Business process reengineering (BPR)
Feasibility analysis (economic, legal,
operational, schedule feasibility)
Describing (tangible and intangible) costs
and benefits of each solutions
Propose alternative solutions (keep or
revise old system, or get a new system)
8
Step 2. System Analysis 1
•
•
•
Data collection to gather data for
information needs, resources, and
capabilities
Data analysis for data modeling and
activity modeling
Requirement analysis is to “determine
user, stakeholder, and organizational
needs” (p526).
9
Step 2. System Analysis 2
•
•
Determine the nature and scope of the
project.
Sources of data
– Observations of users (conversations)
– Written documents
– Computer-based information
10
Step 2. System Analysis 3
•
Traditional Data Collection
–
–
–
–
Interviews (individuals and groups)
Observing users
Questionnaires
Reviewing documents
11
Step 2. System Analysis 4
•
•
•
Joint application development (JAD)
A highly organized intensive workshop to
bring together system owners
(managers), users, and technicians (e.g.,
analysts, programmers, engineers) to
jointly define and design systems
“[A]nalysts control the sequence of
questions answered by users” (p.192)
12
Step 2. System Analysis 5
•
•
•
•
•
Computer-aided software engineering
(CASE) tools
Data flow diagram (DFD),
System flowcharts (flow diagram)
Connectivity diagrams, grid charts,
decision tables,
Object-oriented analysis
13
Step 2. System Analysis 6
•
•
•
Business process reengineering (BPR)
“[L]ooking for new ways to perform
current tasks” rather than “automating
existing processes” (p.197).
“[N]ot just to improve each business
process, but, … to reorganize the
complete flow of data … to eliminate
unnecessary steps, achieve synergies
among … separate steps…” (p.197).
14
Step 2. System Analysis 7
•
•
•
Key business processes are “structured
set of measurable activities designed to
produce a specific output for a particular
customer or market” (p.198).
Is an activity dysfunctional? Important?
Feasible?
Employ disruptive technologies that
“enable the breaking of long-held
business rules that inhibit …” (p.199).
15
Data Flow Diagram 1
• A picture of the movement of data
between external entities and the
processes and data stores within a system
• Data flow (arrow)
• Process (work or actions)
• Data store in rectangular
• Source/sink
16
Data Flow Diagram 2
• Context diagram or level-0 diagram
• Overview of an organizational system that
shows the system boundaries, external
entities that interact with the system, and
the major information flows between the
entities and the system
• Level-n diagram is a data flow diagram
that is n nested decompositions from a
process on a level-0
17
Data Flow Diagram 3
• Data flow allows only one direction
• Data flow from and to data store means
retrieving and updating information
• Process (verb) has to have input and
output
• Data store must be moved by a process
• Source/sink
18
Context DFD
19
20
Level 1 DFD
21
Context DFD
22
Level 0 DFD
23
Flowchart
Start
Read x
sum = 0
i=1
sum = sum + i
Yes
i= i+1
If i <= x
No
Print sum
End
24
Step 3. System Design 1
•
•
•
•
•
Logical and functional designs
Defines input/output requirements (forms
and reports)
Design user interfaces and dialogues
Design database/storage (data
dictionary)
Specifies H/W, S/W, and networking
(telecommunication)
25
Step 3. System Design 2
•
•
•
System controls (I/O, process, database,
telecommunication personnel control)
Rules and procedure (security, privacy,
data integrity, and backups--recovery).
Described in request for proposal (RFP)
specifying required resources (H/W, S/W)
26
27
Highlights
• Iteration, but not a one-shot game
• Not a technicians’ job but all stakeholders’
jobs to improve their performances
• User centered approach; keep analyzing
users needs all the time
• Emphasis on reliability, security, privacy
especially for contracting out projects
• Importance of documentation in all stages.
28