Information Systems Reengineering

Shi-Ming Huang

ContentsContents Section 1

An Overview of Information Systems Reengineering

Section 2Year 2000 Storm

Section 3 Systematic Approach for Information Systems Reengineering

Section 4Artificial Intelligence Approach for Information Systems Reengineering

Section 1 Section 1 An Overview of Information Systems ReengAn Overview of Information Systems Reeng

ineeringineering References:1. P.H. Newcomb, “Web-Based Business Process Reengineeri

ng,” IEEE Software, Nov. 19952. J.J. Donovan, “Business Reengineering with Information Te

chnology”, Prentice Hall, 1994, ISBN 0-13-125907-5.3. J.M. Gallaugher and S.C. Ramanathan, “Choosing A Client/S

erver Architecture: A Comparsion of Two and Three Tier Systems,” Information Systems Management, Spring 1996.

4. T. Cheung, J. Fong, and B. Siu, “Database Reengineering and Interoperability”, Plenum, 1995, ISBN 0-306-45288-X

5. R.S. Arnold, “Software Reengineering”, IEEE Press 1993, ISBN 0-8186-3272-0

6. J. Fong and S. Huang, “Information Systems Reengineering”, Springer Verlag, 1997, ISBN 981-3083-15-8

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 ReWhat is Information System Reengineering?engineering?

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 ReWhat is Information System Reengineering?engineering?

With the advent of each new form of technology, there has been a need to redesign and re-implement 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.

What is Information System ReWhat is Information System Reengineering?engineering?

Business Reengineering Process Client Server Information System WWW Multimedia Database System Y2K Storm Expert Database System

The Challenge of Information SThe Challenge of Information Systems Reengineering for Year ystems Reengineering for Year 20002000

Business Reengineering ProcessBusiness 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

Reverseengineering

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 applications to new host systems

Adapt an existing business process to perform in new business functions

Forwardengineering

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

Datareengineering

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 ProcesBusiness Reengineering Processs

The most critical aspects of the BPR process:

1. understanding the roles existing systems play

2. identifying reusable components and

3. locating and adapting reusable components to support new business processes.

Business Reengineering ProcesBusiness Reengineering Processs

BPR Failure:1. 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.

2. lack of information-technology infrastructure are major impediments to BPR implementation.

Business Reengineering ProcesBusiness Reengineering Processs

BPR Successful:1. Successful BPR efforts usually involve caref

ully planned incremental change in reasonably sized chunks, rather than radical change done all at once.

2. A powerful technologies for software reverse engineering, reengineering, and reuse

3. based on the observation that the more automatic and accessible

4. the less complicated and more applicable

Client Server Information SysteClient Server Information Systemm

Two Tier Architecture1. Clent Tier: User Interface, Data Processing

2. Server Tier: Data Processing, Data Server

Three Tier Architecture1. Presentation tier

2. Functionality tier

3. Data tier

Protect existing IT Investments Ensure the firm’s ability to adopt new tech

nologies Provide integration of heterogeneous res

ources Accommodate emerging standards embra

ced by a board base of firms

Three Tier Client Server Architecture

The Future Business Design ThrThe Future Business Design Through Information Technologyough Information Technology

Rapid Application Development Migration to open systems and gradual do

wnsizing System Connectivity Evaluation to a Gateway Architecture Applications built from scratch

Moving current information technologMoving current information technology infrastructure to the client-server ary infrastructure to the client-server architecturechitecture

IImplement 3-tiered architecture mplement 3-tiered architecture which utilizes current systemswhich utilizes current systems

User Interface

NetMinder

NamingServer

FunctionalityServer

AsynchronousConnectivity

Server

Machine A

Machine B

Machine C

Current SystemsAdded Functionality & Connectivity

& Connectivity tools

FUNCTIONALITYPRESENTATION DATA

Complete new 3-tiered system, Complete new 3-tiered system, which eliminates most of old syswhich eliminates most of old system.tem.

User Interface

NetMinder

NamingServer

FunctionalityServer

AsynchronousConnectivity

Server

Machine A

Machine B

Machine C

Any Remaining SystemsExpanded tools & Connectivity Tools

(as needed)

FUNCTIONALITYPRESENTATION DATA

New Data

SecurityServer

SQL Database Server

Database machine accesses data Database machine accesses data through servers; data is then pasthrough servers; data is then passes through server to clientsses through server to clients

ExistingClients

NetMinderNamingServer

FunctionalityServer

AsynchronousConnectivity

Server

Machine A

Machine B

Machine C Existing Systems

FUNCTIONALITYPRESENTATION DATA

SecurityServer

DatabaseMachine

FunctionalityServer

SQL Database ServerHigh-Speed

Computer acting as "data gateway"

Multimedia Database SystemMultimedia Database System

The new applications require rich data types.

WWW (World Wide Web)WWW (World Wide Web)

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. Browser HTML/Hypertext Markup Language http (hypertext transport protocol) server

WWW (World Wide Web)WWW (World Wide Web)

Internet/Intranet HTML Java, ActiveX, and scripting langu

ages have proven to be a convenient way to distribute information internally

CGI (Common Gateway Interface) and API to integrate with Databases

Approaches to Reengineering- Approaches to Reengineering- Migration or ConversionMigration or Conversion Selecting a Database Model

File Structure Hierarchical Data Model Network Data Model Relational Data Model Object-Oriented Data Model

Approaches to Reengineering- Approaches to Reengineering- Migration or ConversionMigration or Conversion Database Conversion

Parallel Conversion Direct Cut-Over Phase-In

Approaches to Reengineering- Approaches to Reengineering- Migration or ConversionMigration or Conversion Schematic heterogeneity:

naming conflicts domain conflicts meta-data conflict structural conflicts

Approaches to Reengineering- Approaches to Reengineering- Migration or ConversionMigration or Conversion Operation heterogeneity

the granularity of the data to be handled difference,

the functionality difference, the association and sharing with other syste

ms difference.

Approaches to Reengineering- Approaches to Reengineering- Migration or ConversionMigration or Conversion Limited functionality and general informa

tion the ideal integrating system should support t

he 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.