Transcript Information Systems Reengineering

Information Systems
Reengineering
Shi-Ming Huang
Contents
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Section 1
An Overview of Information Systems
Reengineering
Section 2
Year 2000 Storm
Section 3
Systematic Approach for Information Systems
Reengineering
Section 4
Artificial Intelligence Approach for Information
Systems Reengineering
Section 1
An Overview of Information Systems Reengineering
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References:
P.H. Newcomb, “Web-Based Business Process
Reengineering,” IEEE Software, Nov. 1995
J.J. Donovan, “Business Reengineering with Information
Technology”, Prentice Hall, 1994, ISBN 0-13-125907-5.
J.M. Gallaugher and S.C. Ramanathan, “Choosing A
Client/Server Architecture: A Comparsion of Two and Three
Tier Systems,” Information Systems Management, Spring
1996.
T. Cheung, J. Fong, and B. Siu, “Database Reengineering
and Interoperability”, Plenum, 1995, ISBN 0-306-45288-X
R.S. Arnold, “Software Reengineering”, IEEE Press 1993,
ISBN 0-8186-3272-0
J. Fong and S. Huang, “Information Systems
Reengineering”, Springer Verlag, 1997, ISBN 981-3083-15-8
What is Information System
Reengineering?
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To extract the contents, structure, and flow of
data and process contained within exiting
system software in a form amenable to inquiry,
analysis and documentation.
The process of modifying the internal
mechanisms of a system or problem or the data
structures of a system or program without
changing its functionality
The examination and alteration of a subject
system to reconstitute it in a new form and sub
subsequent implementation of that form
What is Information System
Reengineering?
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Software Reengineering: improves one’s
understanding of software, or prepares or improves
the software itself, usually for increased
maintainability, reusability, or evolvability.
Your business must constantly adapt to a
dynamically changing environment. Therefore you
must choose an adaptive, dynamic information
architecture that has the flexibility to support both
changes in the business environment and changes
in technology.
The Information System Reengineering approach is
to modernize your information technology
infrastructure in order to sustain a competitive
advantage in today’s dynamic environment.
What is Information System
Reengineering?
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With the advent of each new form of technology,
there has been a need to redesign and reimplement existing Information Systems.
Reengineering involves the redesign of the
existing Information Systems, while using as
much of the existing system as possible. That is,
the approach taken is to transform the existing
Information System into the format needed for
the new technology, rather than to throw away
the old system. Such an approach has obvious
benefits, particularly if it can be automated
and/or supported by methods and tools.
The Challenge of Information
Systems Reengineering for Year 2000
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Business Reengineering Process
Client Server Information System
WWW
Multimedia Database System
Y2K Storm
Expert Database System
Business Reengineering Process
Activity
Software Reengineering
Business process Reengineering
Restructuring
Reorganize source code to perform
some basic functions more
efficiently
Reorganize people, systems, and
infrastructure to perform some basic
functions in potentially more
efficient ways
Reverse
engineering
Examine design of existing software
system by deriving design from
existing source code
Examine design of existing business
process by extracting design from
existing implementation
Retargeting
Transport existing source code and
Adapt an existing business process to
applications to new host systems
perform in new business functions
Forward
engineering
Develop new system design based
on integration of new system
requirements into existing
system design
Establish new business-process design
based on integration of new business
requirements into existing business
processes
Data
reengineering
Restructure the organization and/or
format of stored information for
use by software applications
Restructure the organization or format of
information for use by either more
manual or
automated processing activities
Business Reengineering Process
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The most critical aspects of the BPR
process:
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understanding the roles existing systems
play
identifying reusable components and
locating and adapting reusable components
to support new business processes.
Business Reengineering Process
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BPR Failure:
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One explanation for BPR failure is that
business managers frequently
misunderstand the crucial roles that existing
information systems will continue to play
after the new business process is
implemented.
lack of information-technology infrastructure
are major impediments to BPR
implementation.
Business Reengineering Process
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BPR Successful:
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Successful BPR efforts usually involve
carefully planned incremental change in
reasonably sized chunks, rather than radical
change done all at once.
A powerful technologies for software reverse
engineering, reengineering, and reuse
based on the observation that the more
automatic and accessible
the less complicated and more applicable
Client Server Information System
Two Tier Architecture
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Clent Tier: User Interface, Data Processing
Server Tier: Data Processing, Data Server
Three Tier Architecture
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3.
Presentation tier
Functionality tier
Data tier
The Future Business Design Through
Information Technology
Protect existing IT Investments
 Ensure the firm’s ability to adopt new
technologies
 Provide integration of heterogeneous
resources
 Accommodate emerging standards
embraced by a board base of firms
 Three Tier Client Server Architecture
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Moving current information technology
infrastructure to the client-server architecture
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Rapid Application Development
Migration to open systems and gradual
downsizing
System Connectivity
Evaluation to a Gateway Architecture
Applications built from scratch
Implement
3-tiered architecture which
utilizes current systems
PRESENTATION
FUNCTIONALITY
DATA
NetMinder
Naming
Server
Machine A
Functionality
Server
User Interface
Machine B
Asynchronous
Connectivity
Server
Machine C
Current Systems
Added Functionality & Connectivity
& Connectivity tools
Complete new 3-tiered system, which
eliminates most of old system.
PRESENTATION
FUNCTIONALITY
DATA
NetMinder
Naming
Server
Security
Server
Machine A
Functionality
Server
New Data
Machine B
User Interface
Asynchronous
Connectivity
Server
SQL Database
Server
Machine C
Any Remaining Systems
Expanded tools & Connectivity Tools
(as needed)
Database machine accesses data
through servers; data is then passes
through server to clients
PRESENTATION
FUNCTIONALITY
NetMinder
Security
Server
DATA
Naming
Server
Machine A
Functionality
Server
Machine B
Database
Machine
Existing
Clients
High-Speed
Computer acting as
"data gateway"
Functionality
Server
Asynchronous
Connectivity
Server
SQL Database
Server
Machine C
Existing Systems
Multimedia Database System
The new applications require rich data types.
WWW (World Wide Web)
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Fast Growth: In January 1993 there were
about 50 WWW Servers in the world. In
mid-1996, there were over 100,000
external WWW Servers.
There are three main parts of the Web.
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Browser
HTML/Hypertext Markup Language
http (hypertext transport protocol) server
WWW (World Wide Web)
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Internet/Intranet
HTML Java, ActiveX, and scripting
languages have proven to be a
convenient way to distribute information
internally
CGI (Common Gateway Interface) and
API to integrate with Databases
Approaches to ReengineeringMigration or Conversion
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Selecting a Database Model
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File Structure
Hierarchical Data Model
Network Data Model
Relational Data Model
Object-Oriented Data Model
Approaches to ReengineeringMigration or Conversion
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Database Conversion
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Parallel Conversion
Direct Cut-Over
Phase-In
Approaches to ReengineeringMigration or Conversion
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Schematic heterogeneity:
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naming conflicts
domain conflicts
meta-data conflict
structural conflicts
Approaches to ReengineeringMigration or Conversion
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Operation heterogeneity
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the granularity of the data to be handled
difference,
the functionality difference,
the association and sharing with other
systems difference.
Approaches to ReengineeringMigration or Conversion
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Limited functionality and general
information
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the ideal integrating system should support
the full functionality of both systems plus
some additional functionality arising from
the integration,
the general resource information, (i.e. the
data dictionary), is very poor.