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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 1. 2. 3. 4. 5. 6. 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? 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 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 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 The most critical aspects of the BPR process: 1. 2. 3. understanding the roles existing systems play identifying reusable components and locating and adapting reusable components to support new business processes. Business Reengineering Process BPR Failure: 1. 2. 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 BPR Successful: 1. 2. 3. 4. 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 1. 2. Clent Tier: User Interface, Data Processing Server Tier: Data Processing, Data Server Three Tier Architecture 1. 2. 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 Moving current information technology infrastructure to the client-server architecture 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) 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 ReengineeringMigration or Conversion Selecting a Database Model File Structure Hierarchical Data Model Network Data Model Relational Data Model Object-Oriented Data Model Approaches to ReengineeringMigration or Conversion Database Conversion Parallel Conversion Direct Cut-Over Phase-In Approaches to ReengineeringMigration or Conversion Schematic heterogeneity: naming conflicts domain conflicts meta-data conflict structural conflicts Approaches to ReengineeringMigration 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 ReengineeringMigration 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.