Information Systems Engineering

Information Systems Engineering

INFORMATION SYSTEM ENGINEERING 2

Lecture Outline

• Information Systems Architecture• Information System Architecture components• Information Engineering• Phases of Information Engineering• Features of Information Engineering


Information Systems(IS) Planning

Introduction :

• Sometimes called “enterprise-wide computing” or “Information Architecture”

• Scope of (IS Planning) is now the entire organization

• There is a problem: isolated groups in an organization start their own databases

and it becomes impossible to find out who has what information, where there are

overlaps, and to assess the accuracy of the information

• To support enterprise-wide computing, there must be enterprise-wide information

planning

• One framework for thinking about and planning for enterprise-wide computing is

an Information Systems Architecture or ISA

• Most organizations do NOT have such an architecture


Information Systems Architecture (ISA)

• An ISA is a “conceptual blueprint or plan that expresses the desired future structure for information systems in an organization”

• It provides a “context within which managers throughout the organization can make consistent decisions concerning their information systems”


Benefits of ISA

– Provides a basis for strategic planning of IS

– Provides a basis for communicating with top management and a

context for budget decisions concerning IS

– Provides a unifying concept for the various stakeholders in information

systems.

– Communicates the overall direction for information technology and a

context for decisions in this area

– Helps achieve information integration when systems are distributed

– Provides a basis for evaluating technology options (for example,

downsizing and distributed processing)


Zachman ISA Framework components

– Data• The “What” of the information system

– Process• The “How” of the information system

– Network• The “Where” of the information system

– People• Who performs processes and are the source and

receiver of data and information.– Events and Points in time• When processes are performed

– Reasons• Why: For events and rules that govern processing


Roles of Data, Process and Network

• Six perspectives of the Data, Process and Network components

– Business scope (Owner)

– Business model (Architect)

– Information systems model (Designer)

– Technology model (Builder)

– Technology definition (Contractor)

– Information system (User)


Explanation of the components

Data Process Network

1. Enterprise Scope(Owner)

List of entitiesimportant tothe business

List of processesor functions thatthe businessperforms

List of locations inwhich the businessoperates


Explanation of the components (contd….)


2. Enterprise Model(Architect)

Business entities andtheir relationships

Function and processdecomposition Communications links

between business locations




3. Information System Model(Designer)

Model of the businessdata and their relationships (ERD in Database design)

Flows between application processes

Distribution Network




4. Technology Constrained Model(Builder)

Database Design (logical) Process specifications Database Design




5. Technology Definition/Detailed Representations

(Contractor)

Database Schema and subschema definition

Program Code andcontrol blocks

Configurationdefinition/ NetworkArchitecture




6. Functioning Enterprise(User)

ImplementedDatabase and information

CurrentSystemConfiguration

ImplementedApplicationPrograms


Information Engineering• Information Engineering:

“an interlocking set of formal techniques in which enterprise models, data models and process models are built... and are used to create and maintain Information Systems”

James Martin (1986)


• Object-oriented concepts• Database technology (Relational, Hierarchical, Network )

• Data oriented methodology• Data analysis and data management• Full lifecycle coverage• Focus on data and activities• The use of tools such as CASE(Computer Aided

Software Engineering) • Note: CASE tools are a class of software that automate many of

the activities involved in various life cycle phases

Information Engineering (contd….)

http://en.wikipedia.org/wiki/Software

http://en.wikipedia.org/wiki/Product_lifecycle_(engineering)


• Strategic data models• Alignment of information systems planning

with strategic business planning• Process modeling techniques• top-down analysis and development of

organization's applications

Information Engineering (contd….)


1. Information strategy planningto build an information and technology architecture to support business strategy and objectives

2. Business area analysisto identify data and function requirements of each business area

3. Individual systems planning4. Individual Systems design

to complete logical specifications for a system and convert these into physical design specifications

5. Constructionto generate code, test, and install the system

6. Cutover

Major Phases of Information Engineering


Phase 1 - information strategy planning:

• business mission, objectives, CSFs, performance measurements, organization structure, current situation

• construct corporate data model• determine major business area/functions• determine:– information architecture (global entities and business area/functions )– technical architecture (technology: HW/SW/Comm.)– information strategy plan (priorities)


Phase 2 - Business Area AnalysisThe Business Area Analysis must help in the following:• identify and model in detail the fundamental data and activities required

to support a business area• ensure that requirements enable business area’s goals and CSFs to be

supported• ensure that requirements are independent of :

– technology– current systems and procedures– current organizational structure

• a high-level executive sponsor is necessary


Business area analysis: steps• extract the relevant entity relationship model and business-

function decomposition models• identify relevant departments, locations, business goals, CSFs• create a preliminary data model: identify events, entity life

cycles, initial attributes• create a preliminary process model: decompose the functions

into processes• model data and processes of existing systems for comparison• involve all affected end-users in iteratively building:

a detailed data model, a detailed process model, entity / process matrices

• identify and priorities system development projects


Business area analysis: techniques

• data modelentity relationship modelingattribute collectionnormalizationcanonical synthesis

• process modelprocess decomposition modelsprocess dependency diagrams

• data and activity interactionentity lifecyclesprocess / entity matrix


Information engineering: phases 3 and 4• Phase 3 - individual systems planning

Although it is individual but we have to use JRP (Joint Requirement Planning) for individual systems planning

• Phase 4 - individual system design• concerned with how selected processes in the business are

implemented in procedures and how these procedures work• direct end-user involvement is essential• identify reusable procedures• use prototyping• use JAD (Joint Application Design)


System design techniques1. prototyping2. detailed process models: procedure design using access

path and volumes analysis, dialogue flows and menu structures,

3. physical database design, file design, 4. screen displays5. menu flows6. report layouts7. batch procedures and software8. design verification and testing


• Phase 5 - construction: technical design, create physical databasescreate modules and programs, unit testingsystem testing, documentation

• Phase 6 - cutover:conversionfinal testingconduct traininginstall the system, review implementation

Information engineering: phases 5 and 6


Information Engineering Features

• organization-wide perspective aligned with strategic business

planning

• Comprehensive (complete, full)

• emphasis on user involvement e.g. JAD, JRP

• evolves by incorporating new techniques, concepts,

technologies e.g. object-oriented concepts

• emphasis on automation e.g. 4GLs, I-CASE, prototypes


• primarily for database transaction processing systems• flexible paths through the methodology e.g. reverse

engineering and re-engineering

Information Engineering Features (Contd….)


References

• Avison, D.E. & Fitzgerald, G. (2003). Information Systems Development: Methodologies, Techniques and Tools. (3rd ed), McGraw-Hill, London. Chapters 20.1, 20.3

• www.courses.ischool.berkeley.edu

• www.slideserve.com/.../information-systems-planning-

• www.ou.edu/class/aschwarz/Database/

http://www.courses.ischool.berkeley.edu/

http://www.slideserve.com/.../information-systems-planning-






http://www.ou.edu/class/aschwarz/Database/



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Information Systems Engineering