Introduction To Dss By Satyawan Dhankhar

DECISION SUPPORT SYSYTEM An Overview

Introduction Decision making can be regarded as an outcome of mental processes leading to the selection of a course of action among several alternatives. Every decision making process produces a final choice. Decision are made with two kind of information:Ø Internal Ø External

Level of Decision Making

Types of Decisions Structured decision:- are those for which a set of rules and procedure for the decision making process can be determined and utilized in subsequent decision situation. Unstructured Decision:- are those for which preplanned rules and regulation can’t be completely specified. Semi-structured:- it lies somewhere between structured and unstructured decision. Algorithm

Heuristic Decreasin g Unstructure d

Semistructured

Increasi ng

structured

History of DSS Ø The concept of decision support systems was first articulated by Scott Morton in February 1964. Ø T.P. Gerrity, Jr. focused on DSS design issues in his 1971article titled "The Design of Man-Machine Decision Systems

Ø Peter Keen and Michael Scott Morton argued in 1978, "A DSS is more a service than a product”.

Decision support system Keen (1980): DSS apply “to situations where a ‘final’ system can be developed only through an adaptive process of learning and evolution”

Central Issue in DSS Ø Support and improvement of decision making

Definition of DSS A DSS is an interactive, flexible, and adaptable CBIS, specially developed for supporting the solution of a non-structured management problem for improved decision making. It utilizes data, it provides easy user interface, and it allows for the decision maker’s own insights.

Characteristics and Capabilities of DSS ØProvide support in semi-structured and unstructured situations. ØSupport for various managerial levels. ØSupport all phases of the decisionmaking process. ØGoal is to improve the effectiveness of decision making. ØDecision makers can make better, more consistent decisions in a timely manner.

Traditional Systems Development Life Cycle (SDLC)

WHY DSS…… Ø The declining in the cost of computers hardware increase the use of hardware and software tools Ø It provides types of information that help the managers to take decisions. Ø Large increase in no. of packages software which can be used to directly to implement DSS application. Ø Graduates know how to use tools that DSS provide to make semi-structured and unstructured decision.

DSS SOFTWARE Ø DSS is a system that accomplish the work. Ø DSS generator can be adopted in different situations. Ø DSS tools are used to build both specific DSS and DSS generators. Ø Tools include programming language, data manipulation software, special graphic software.

DSS Technology Levels Specific DSS D S S G e n e ra to rs ( Spreadsheets , …) D S S To o ls ( L a n g u a g e s , …)

COMPONENTS OF DSS 

1. Data Base Management Subsystem

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2. Model Base Management Subsystem

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3. Dialogue generation and management system.

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Components of DSS

The Data Base Management Subsystem A data base management system (DBMS) is a computer program designed to manage a database and run operations on the data requested by numerous clients. Typical examples of DMS use include accounting, human resources and customer support systems

Ca p a b ilit ie s o f DBMS Ø Captures/extracts data for inclusion in a DSS database. Ø Interrelates data from different sources. Ø Performs complex data manipulation tasks based on user queries. Ø Handling temporary and ad hoc data base. Ø Interfacing with the model

Model Base Management system

MBMS is a computer program that includes financial, statistical, management science or other quantitative models that provide the system’s analytical capabilities and appropriate software management. Capabilities of MBMS are: Ø Allows user to manipulate the models so they can conduct experiments and sensitivity analyses ranging from ‘what-if” to goal seeking. Ø Catalogs and displays the directory of models for use by several individuals in the organization.

Dialog Generation and Management System The dialog subsystem provides DSS much of its power, Flexibility and usability characteristics. It’s Capabilities are; Ø Handling a variety of dialog styles according to user needs. Ø Shifting between dialogue styles are needed. Ø Accommodating a variety of users interface device and mechanisms. Ø Presenting results in a variety of formats and media.

DSS Types By Steven Alter File drawer systems Ø allow immediate access to data items Ø simplest DSS

Data analysis systems Ø allow

the manipulation of data by means of operators tailored to the task and settings or operators of a general nature

Analysis information systems Ø provide access to a series of databases and

small models

Continued… Representation models Ø estimate

the consequences of actions on the basis of models that are partially no definitional Ø reflect uncertainty, often in individual or collective human behavior, or represent the dynamic behavior of systems over time Ø widely used to forecast the future effect of a decision

Continued… Optimization systems Ø provide

guidelines for action by generating the optimal solution consistent with a set of constraints

Suggestion systems Ø perform mechanical work leading to a

specific suggested decision for a fairly structured task

Using DSS….. Using a decision support system involves an interactive analytical modeling process Ø Decision makers are not demanding pre-specified information Ø They are exploring possible alternatives What-If Analysis Ø Observing how changes to selected variables affect other variables Sensitivity Analysis Ø Observing how repeated changes to a single variable affect other variables Goal-seeking Analysis Ø Making repeated changes to selected variables until a chosen variable reaches a target value Optimization Analysis Ø Finding an optimum value for selected variables, given certain constraints

Examples …. Ø AIMS Ø EIS Ø GADS Ø GODDESS Ø GPLAN Ø PAMPS

Expert System An Expert System (ES) ØA knowledge-based information system ØContain knowledge about a specific, complex application area ØActs as an expert consultant to end users

Components of ES Knowledge Base Ø Facts about a specific subject area Ø Heuristics that express the reasoning procedures of an expert (rules of thumb) Software Resources Ø An inference engine processes the knowledge and recommends a course of action Ø User interface programs communicate with the end user Ø Explanation programs explain the reasoning process to the end user

Components of ES