Decision Suppport System

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DSS

Introduction

Decision Support Systems, conventionally called as DSS deal with the design and the useof cognitively compatible computerized systems for-

1. Assisting the managers in taking more effective decisions concerning semi-structured and unstructured tasks.

2. Supporting, rather than replacing, managerial intuition and judgement3. Improving the effectiveness of decision making rather than its efficiency. (K Keen

and Scott-Morton [1978]

Growths in computer and information technology and the realization of the inherentlimitations of individuals capability to take effective decisions in dynamic, unstructuredand semi-structured decision situations, have naturally led to the development and use of

various concepts and tools for using computer in making decisions.

Some Definition of DSS

A. Mann and Watson [1984] observed that DSS is an interactive system that providesthe user with easy access to decision models and data in order to support semi-

structured and unstructured decision making tasks.B.According to Young [1983], the distinction of DSS is that they seek to establish asymbiosis of human- mind and computer by allowing a high degree of human-computer interaction and by enabling the manager-user to maintain direct controlover the computers tasks and their outcomes. Three supports that DSS providesto manager are:

i. The assistance to the manager in problem exploration and definition,ii. Help in formulating alternate solutions, andiii. Help to select strategy or a plan.

C. Blanning [1986] states that an important purpose of the research being done inDSS is to develop a framework for information management that is asindependent as possible of the way in which the information is stored andprocessed.

D.Crescenzi and Gulden [1983] argues that DSS has emerged from the ashes ofMISs failure to support decision-making by management in businesses, whichfind themselves data-rich but information-poor.

E.According to Watson and Hill [1983] DSS supports the toughinformation requeststhat MIS has not been able to serve.


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F. Sprague and Carlson [1982] observe that unfortunately the intuitive validity of thewords in Decision Support Systemhas tempted many to define DSS as any systemthat supports a decision or that makes some contribution to decision making, thusbringing in its fold all but transaction processing.

Features of DSS

From the above definitions it is evident that there is no universal definition of DSS.However, a quick survey of existing literature will reveal that most authors eitherexplicitly or implicitly believe that a DSS should have the following nine basiccharacteristics.

i. DSS assists managers in their decision making specifically in semi-structured andunstructured fields.

ii. DSS supports and enhances, rather than replaces, managerial decisions.iii. DSS improves the effectiveness of the decision rather than its efficiency.iv. DSS combines the use of models and analytical techniques with conventional data

access and retrieval functions.v. DSS has features (including interactive features) which make its use by non-

computer people easier.vi. DSS has enough flexibility to accommodate changes in the environment, the

approach and the needs of the users.vii. DSS supports managers at all levels that take decisions.viii. DSS is user initiated and user controlled.

ix. DSS supports the personal decision making styles of individual managers. [16]

Three Technology Levels of DSS

The three levels of hardware/software which have been included in the label "DSS" are:

Specific DSS

The system, which actually accomplishes the work, might be called the specific DSS.

It is an information systems "application", but with characteristics that make itsignificantly different from a typical data processing application. An early example is theportfolio management system [Keen & Scott Morton (1978)] and the police beatallocation system used in the city of San Jose, California [Carlson & Sutton (1974)].


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DSS Generator

The second level of technology might be called a DSS generator. This is a "package" ofrelated hardware and software which provides a set of capabilities to quickly and easilybuild a Specific DSS. For example, the police beat system described above was built from

the Geo-data Analysis and Display System (GADS) at the IBM Research Laboratory inSan Jose [Carlson et al. (1974)]. Another example is the Executive Information System(EIS) marketed by the Boeing Computer Services.

DSS Tools

The third and the most fundamental level of technology is called DSS tools. These arehardware or software elements, which facilitate the development of a specific DSS or aDSS Generator. For example, the GADS system described above was written inFORTRAN using an experimental graphics subroutine package as the primary dialogue

handling software, a laboratory enhanced raster scan color monitor and a powerfulinteractive data extraction/database management system.

Components of DSS

A DSS consists of essentially three components or modules. They are:

i. Database Management Moduleii. Knowledge or model management Moduleiii. Dialog or User Interface Module

DSS also includes a complex software system to seamlessly integrate all thesecomponents. The software system should have interface with these three components.Generally the software system is comprised of three sets of capabilities: databasemanagement software (DBMS), model base management software (MBMS) and thesoftware for managing the interface between the user and the system, which might becalled the dialogue generation and management software (DGMS).

The following section deals with the details of individual components of DSS.

The Data Subsystem

The typical advantages of the database approach and the powerful functions ofthe DBMS are important to the development and use of a DSS.

The key characteristics of the data subsystem is shown in the figure 2.2

A partial set of capabilities required in the database area is:


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the ability to combine a variety of data sources through a data capture andextraction process;

the ability to add and delete data sources quickly and easily; the ability to portray logical data structures in user terms so the user

understands what is available and can specify needed additions and

deletions; the ability to handle personal and unofficial data so the user can experiment

with alternatives based on personal judgement; and the ability to manage this wide variety of data with a full range of data

management functions

The Model Subsystem

A very promising aspect of a DSS is its ability to integrate data access and decisionmodels. It does so by imbedding the decision models in an information system,

which uses the database as the integration and communication mechanismbetween models. This characteristic unifies the strength of data retrieval andreporting from the EDP field and the significant developments in managementscience in a way the manager can trust. This area was studied by Sprague &

Watson (1980, 81) and Will & Hart (1975). The key capabilities for a DSS in themodel subsystems include:

ability to create new models quickly and easily the ability to catalog and maintain a wide range of models, supporting all

levels of management;

the ability to inter-relate these models with appropriate linkages throughdatabases;

the ability to access and integrate model "building blocks" and the ability to manage the model base with management functions analogous

to database management.

The User-Interface

Much of the power, flexibility and usability characteristics of a DSS are derivedfrom capabilities in the user system interface. Bennet (1977) identifies the user,

terminal and software system as the components of the interface system.

1. The action languagewhat the user can do in communicating with thesystem. It includes options like keyboard, touch panels, joy sticks etc.

2. The display or presentation languagewhat the user sees. It includes options likeline printer, display screen etc.


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3. The knowledge basewhat the user must know. This consists of what theuser needs to bring to the session with the system in order to effectively useit.

The desirable capabilities for a DSS to support the user system interface includes:

ability to handle a variety of dialogue styles; the ability to accommodate user actions in a variety of media; the ability to present data in a variety of formats and media the ability to provide flexible support for the users knowledge base.

Current Trends in DSS Components

Current improvements in information technology have led to addition of newdimensions in DSS components. This section discusses few of them.

Present databases used for DSS are found to support the following features:

i. Various Levels of Details: Different institutions require varying level of detailof data to support the system. Present databases are made flexible to meetthis requirement.

ii. Varying Amounts of Data: Ad hoc DSS maintain only those data that areactually used for the decision making system, whereas institutional systemsmaintain a large amount of potentially relevant data.

iii. Varying Degree of Accuracy: Absolute accuracy of data is not important insmall level DSS whereas they are important in some critical DSS.

iv. Support for memories:Sprague and Carlson [1982] suggest four kinds ofmemory aids that a DSS database should typically support: workspaces,libraries, links and triggers.

v. Support for Relationships and Views:These are essential to allow the managersto test alternate scenarios quickly and with relative ease.

vi. Random Access:This facility is generally available in all commercial database.vii. Security and Private database:Gains importance when data is shared across an

organization, with different levels of restrictions applied on it.

Present model management systems or software take a different viewpointregarding model bases. Some of the current trends are:

i. Relational view of models:Just like relational view of data, it is assumed thatmodel is a file created by running the model for all possible values of its


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inputs and recording the inputs and resulting outputs as records in a file, inwhich inputs are key attributes and outputs are content attributes.Languages similar to database query languages have been developed, likeMQL [Model Query Language], TQL [Table Query Language] etc.

ii. Expert Modelbase Systems:Expert Modelbase Systems involve applicationartificial intelligence in efficiently manipulating models. This area consistsof three sub-areas: (1) Application of AI to model construction, (2) theapplication of AI to model base integration and (3) the application of AI tothe interpretation of model outputs.

iii. Graph based approach to Model Management:Application of graph theory inmodel management systems.

User interfaces are becoming more and more sophisticated with increasingadvancement in computer graphics and powerful visual tools. An emerging area inbusiness graphics is interactive visual decision-making (IVDM). IVDM allows a

manager to visually create or modify a model of complex decision situation. Themanager can experiment with various decision alternatives, and see on thecomputer screen, the effect of different alternatives, in a graphical, even dynamicform on systems measures of performance. AI techniques are also incorporatedinto IVDM, providing it with extended capabilities like dynamic optimization,specialized output etc.

Developing and Using DSS

A number of activities are required before a DSS is available to support decision-making.The organization must plan and organize both computers and human resources. As withmost organizational endeavors, thoughtful planning and organizing is an important key tosuccess. Once the planning and organizing for DSS has been accomplished, thedevelopment of specific DSS can begin. After it has been created, it can be put into use.

This is when the payoff from the DSS is received. It should support all phases ofdecision making process and enhance the decision maker(s) effectiveness.

Management becomes involved with a DSS in a variety of ways: as approver and

administrator, as developer, as operator and as user of output. A brief description ofissues relevant to managements involvement follows.

i. As Approver and Administrator:Here the manager is functioning in a way quiteconsistent with other planning activities. Some expert remarks regarding this are:o DSS planning should be incorporated into corporate planning processes-

Sprague and Carlson [1982].


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o In planning for implementation of the DSS into organization, the politicalimpact on power should be examined - Ahn and Grudnitski [1985].

o Financial evaluation of DSS is difficult and infrequent- Alter [1975], Keen[1980], McCosh and Scott Morton [1978].

o DSS evaluation should be based upon both value addition and costreduction. - Meador and Keen [1984].

o Aportfolio approach should be utilized which considers risk and reward-Germillion and Pyburn [1985].

ii. As Developer:Given that th function of the DSS is to support the managersdecision making responsibilities, and given that decision making is a difficult taskto specify or structure, it should not seem illogical that the manager would need toplay a substantial role in the DSS development process. Experts have madefollowing remarks regarding this:o Management involvement should be heavy throughout the development.-

Alter [1978], Bahl and Hunt [1985], Ginzberg [1978], McCosh and Scott

Morton [1978], Sprague [1980].o Management should provide leadership in DSS development. - Keen and

Scott Morton [1978], Keen and Wagner [1979].o DSS development should include a fostering of cooperation and

coordination between user/managers and technical designers. - Ahn andGrudnitski [1985].

o User led development approaches often lead to improved DSSperformance. - Kasper [1985].

o The DSS should be developed to include the personal decision-makingstyle of the manager. - Keen [1980], McCosh and Scott Morton [1978].

o The nominal level of available DSS technology has a significant impact onthe extent of user and manager involvement. - Mann and Watson [1984].

iii. As Operator:The actual operation of the DSS requires skills perhaps mostdissimilar to those typically required to managers. There are different levelsoftechnical sophistication in DSS, which require different amounts of ability for use.It is expected that some amount of operational ability and actual operation of theDSS may be desired by managers. Following are observations of experts:o Managers prefer to turn operation of DSS over to their stuffWagner

[1980].o There are a significant number of upper managers sitting at the terminals

Keen and Wagner [1979].iv. User of Output:Last, but probably the most important part is the utilization of

output by management. Experts note that:o The DSS should be used in support of managerial decision making at all

levels of the organization - Keen and Scott Morton [1978], McCosh andScott Morton [1978], Sprague [1980].


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o The DSS should support both individual and group (sequentialinterdependent and pooled interdependent) decision making- Keen andScott Morton [1978], Sanders and Courtney [1985], Sprague [1980].

o The DSS should be able to assist the manager with all phases of decision-making process- Keen and Scott Morton [1978], Sprague [1980].

The evolving DSS Domain: Group Decision SupportSystem

2.7.1 GDSS: An Overview

Decision Support Systems were a revolutionary concept in computer support fordecision making when they first appeared in the 1970s. Nowthey are used in alarge number of organizations. DSS is not a stagnant field, and it continues toevolve.

Group Decision Support Systems (GDSS) are used to improve the efficiency andeffectiveness of groups of people working together. Because of the amount ofitem people spend in group activities, GDSS has tremendous potential value. AGDSS can broadly defined as an interactive computer-based system, whichfacilitates solution of unstructured problems by a set of decision-makers working

together as a group. Components of a GDSS include hardware, software, peopleand procedures. These components are arranged to support a group of people,usually in the context of a decision related meeting.

Basic Feature of GDSS

< Text and data file creation. Modification and storage for group members.

< Word processing for text editing and formatting.

< Learning facilities for nave GDSS users.

< On-line help facilities.


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< Worksheets, spreadsheets, decision trees and other means of graphicallydisplaying numbers and text.


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Web Based Decision Support System

Overview

The world-wide-web is where the action is in developing enterprise-wide decisionsupport systems. Web-based DSS refers to a computerized system which deliversdecision support information or decision support tools to a manager or business analystusing a thin-clientweb-browser like Netscape Navigator or Internet Explorer. Thecomputer server that is hosting the DSS application is linked to users computer by anetwork with the TCP/IP protocol. In many companies, a web-based DSS issynonymous with an enterprise-wide DSS that is supporting large groups of managers ina networked client-server environment with a specialized data warehouse as part of the

DSS.

Advantages over conventional DSS

Web-based DSS have reduced technological barriers and made it easier and less costly tomake decision relevant information available to managers and staff users ingeographically distributed locations. Because of the World-Wide-Web infrastructure,enterprise wide DSS can now be implemented in physically dispersed companies and togeographically dispersed stakeholders including suppliers and customers at a relativelylow cost. Using web-based DSS, organizations can provide DSS capability to managers

over an intranet, to customers and suppliers over an extranet or to any stakeholder overthe global internet. The web should increase the use of a well-designed DSS in acompnay. Using a web infrastructure for building DSS improves the rapid disseminationof best-practice analysis and decision-making frameworks. It should also promote moreconsistent decision making on repetitive decision tasks across an organization.The webalso provides a way to manage a companys knowledge repository and to bringknowledge resources into the decision making process. The web can also reduce some ofthe problems associated with competingthick-cliententerprise-wide DSS design wherespecial software needs to be installed on a managers computer. Web-based DSS shouldreduce IT management and support costa and end-user training costs. With many web-

based DSS and OLAP products, managers with a browser and access to a web-basedDSS have the same type of ad-hoc reporting and interactive data analysis capabilities asthat provided bythick-clientOLAP tools. Web technology is and will continue to changethe way organizations deliver all types of document and data.


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Potential Problems

There are some potential problems with web-based DSS. Users expectations may beunrealistic, especially in terms of how much information they want to be able to access.

There will be technical implementation problems especially in terms of peak

demand/load problems. Training decision-support content providers and providing themwith tools and technical assistance may be costly. The continuing browser war betweenMicrosoft and Netscape are also potential problem for developers with respect to portingissues. Also using the web may result in accumulation of obsolete data.

Web Technologies Commonly Used

Structure of a web-based DSS is different than that of conventional DSS, though thebasic parts remains the same.

The database and modelbase of web-based DSS are typically stored in a dedicatedenterprise web-server. A high-power web-server, capable of handling multiple databasequeries from distributed clients, is a prerequisite. User interface is any browser capable ofdisplaying complex web architecture involving javascript, style-sheets and applets. Theseinterfaces are generally HTML forms, which invoke predefined stored procedures in theserver computer. These procedures, commonly known as CGI programs, are the threadsbetween the client and the server. CGI programs, after running the required query, returnthe result in the form of web-page to the clients. These kind of procedures/programs areoften calledMiddlewares, if they are commercial software.

Listed below are commonly used software for web-based Decision Support Systems:

a. Database:Any commercial database can be used depending on what is supportedby the CGI programs. These databases are accessed by programs through DLLs(in Windows) or some other database drivers. Microsoft techniques likeODBC/DSN are popular choice.

b. Modelbase:Models can written in high-level programming languages like C, C++or Java. Often these models doubles as CGI programs, otherwise they are run bysome other programs.

c. CGI Programs:Popular choices are C, C++, Perl or ASP. This languages arecapable accessing database through either ODBC connectivities or through ownlibrary header functions.

d. User Interface:User-interface are HTML web-page in case of web-based DSS.Recent advancement in web-technologies have opened up many new techniques forbuiding database driven web applications. The low overhaed costs, overall advantage andeasy accessibility may soon replace convetional DSS software with web-based DecisionSupport Systems.

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Decision Suppport System