Information Systems Reengineering Shi-Ming Huang

Contents 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 References: 1. P.H. Newcomb, “Web-Based Business Process Reengineering,” IEEE Software, Nov J.J. Donovan, “Business Reengineering with Information Technology”, Prentice Hall, 1994, ISBN J.M. Gallaugher and S.C. Ramanathan, “Choosing A Client/Server Architecture: A Comparsion of Two and Three Tier Systems,” Information Systems Management, Spring T. Cheung, J. Fong, and B. Siu, “Database Reengineering and Interoperability”, Plenum, 1995, ISBN X 5. R.S. Arnold, “Software Reengineering”, IEEE Press 1993, ISBN J. Fong and S. Huang, “Information Systems Reengineering”, Springer Verlag, 1997, ISBN

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?

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?

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 Reengineering?

Business Reengineering Process Client Server Information System WWW Multimedia Database System Y2K Storm Expert Database System The Challenge of Information Systems Reengineering for Year 2000

Business Reengineering Process ActivitySoftware ReengineeringBusiness process Reengineering RestructuringReorganize 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 RetargetingTransport existing source code and applications to new host systems Adapt an existing business process to 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 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 Process 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 Process BPR Successful: 1.Successful BPR efforts usually involve carefully 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 System Two Tier Architecture 1. Clent Tier: User Interface, Data Processing 2. Server Tier: Data Processing, Data Server Three Tier Architecture 1. Presentation tier 2. Functionality tier 3. Data tier

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 The Future Business Design Through Information Technology

Rapid Application Development Migration to open systems and gradual downsizing System Connectivity Evaluation to a Gateway Architecture Applications built from scratch Moving current information technology infrastructure to the client-server architecture

I mplement 3-tiered architecture which utilizes current systems

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

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

Multimedia Database System The new applications require rich data types.

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) 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 Reengineering- Migration or Conversion Selecting a Database Model  File Structure  Hierarchical Data Model  Network Data Model  Relational Data Model  Object-Oriented Data Model

Approaches to Reengineering- Migration or Conversion Database Conversion  Parallel Conversion  Direct Cut-Over  Phase-In

Approaches to Reengineering- Migration or Conversion Schematic heterogeneity:  naming conflicts  domain conflicts  meta-data conflict  structural conflicts

Approaches to Reengineering- Migration or Conversion Operation heterogeneity  the granularity of the data to be handled difference,  the functionality difference,  the association and sharing with other systems difference.

Approaches to Reengineering- Migration or Conversion Limited functionality and general information  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.