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DECISION SUPPORT SYSTEM

Understand the decision support system

Appreciate the framework for DSS Development

Get a grip of various models

Evolve the individual and organizational models

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Decision support systems: Definitions

Decision support systems are a class ofcomputer-based information systemsincluding knowledge based systems thatsupport decision making activities.
http://en.wikipedia.org/wiki/Information_systemhttp://en.wikipedia.org/wiki/Knowledge_based_systemhttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Decision-makinghttp://en.wikipedia.org/wiki/Knowledge_based_systemhttp://en.wikipedia.org/wiki/Information_system

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Decision support systemsThere are many approaches to decision-making andbecause of the wide range of domains in whichdecisions are made, the concept of decision support

system (DSS) is very broad. A DSS can take manydifferent forms. DSS is a computerized system forhelping to make decisions. A decision is a choicebetween alternatives based on estimates of thevalues of those alternatives. Supporting a decision

means helping people working alone or in a groupgather intelligence, generate alternatives and makechoices.

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Decision MakingThere are often confusion betweenterms MIS and information system.

Information systems include systemsthat are not intended for decisionmaking. MIS is referred to, in a

restrictive sense, as informationtechnology management
http://en.wikipedia.org/wiki/Information_systemhttp://en.wikipedia.org/wiki/Information_technology_managementhttp://en.wikipedia.org/wiki/Information_technology_managementhttp://en.wikipedia.org/wiki/Information_technology_managementhttp://en.wikipedia.org/wiki/Information_technology_managementhttp://en.wikipedia.org/wiki/Information_system

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Framework for Developing Decision

Support SystemA DSS is a system that aids the processof decision making, but that cannot

bring out explicit decision suggestionsor solutions. DSS can bring out suchdecision suggestions or solutions.

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Support System

DSS allows the decision maker (or itsadvisor) to modify, complete, or refine

the decision suggestions provided bythe system, before sending them backto the system for validation. The system

again improves, completes, and refinesthe suggestions of the decision makerand sends them back to for validation.

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Support System

Amodel-driven DSS emphasizesaccess to and manipulation of a

statistical, financial, optimization, orsimulation model. Model-driven DSS usedata and parameters provided by users

to assist decision makers in analyzing asituation; they are not necessarily dataintensive

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Support System

A communication-driven DSSsupports more than one person working

on a shared task; examples includeintegrated tools like Microsoft's NetMeeting or Groove.

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Support System

A data-driven DSS or data-orientedDSS emphasizes access to and

manipulation of a time series of internalcompany data and, sometimes, externaldata.
http://en.wikipedia.org/wiki/Time_serieshttp://en.wikipedia.org/wiki/Time_serieshttp://en.wikipedia.org/wiki/Time_serieshttp://en.wikipedia.org/wiki/Time_series

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Support System

A document-driven DSS manages,retrieves and manipulates unstructured

information in a variety of electronicformats.

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Support System

A knowledge-driven DSS provides

specialized problem solving expertisestored as facts, rules, procedures, or insimilar structures.
http://en.wikipedia.org/wiki/Problem_solvinghttp://en.wikipedia.org/wiki/Problem_solvinghttp://en.wikipedia.org/wiki/Problem_solvinghttp://en.wikipedia.org/wiki/Problem_solving

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Decision Support SystemApplications As mentioned above, there are theoretical

possibilities of building such systems in any

knowledge domain.

Some of the examples is Clinical decision supportsystem for medicaldiagnosis. Other examplesinclude a bank loan officer verifying the credit of a

loan applicant or an engineering firm that has bids onseveral projects and wants to know if they can becompetitive with their costs.
http://en.wikipedia.org/wiki/Clinical_decision_support_systemhttp://en.wikipedia.org/wiki/Medicalhttp://en.wikipedia.org/wiki/Diagnosishttp://en.wikipedia.org/wiki/Diagnosishttp://en.wikipedia.org/wiki/Clinical_decision_support_systemhttp://en.wikipedia.org/wiki/Clinical_decision_support_systemhttp://en.wikipedia.org/wiki/Medicalhttp://en.wikipedia.org/wiki/Diagnosishttp://en.wikipedia.org/wiki/Diagnosishttp://en.wikipedia.org/wiki/Medicalhttp://en.wikipedia.org/wiki/Clinical_decision_support_systemhttp://en.wikipedia.org/wiki/Clinical_decision_support_system

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Decision Support System

DSS is extensively used in business andmanagement. Executive dashboard andother business performance software allowfaster decision making, identification ofnegative trends, and better allocation of

business resources.
http://en.wikipedia.org/wiki/Executive_dashboardhttp://en.wikipedia.org/wiki/Executive_dashboard

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A growing area of DSS application,concepts, principles, and techniques is

in agricultural production, marketing forsustainable development.

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DSS characteristics and capabilities

Support for decision makers in semi structured andunstructured problems.

Support managers at all levels.

Support individuals and groups. Support for interdependent or sequential decisions. Support intelligence, design, choice, and

implementation. Support variety of decision processes and styles. DSS should be adaptable and flexible. DSS should be interactive and provide ease of use. Effectiveness balanced with efficiency (benefit must

exceed cost

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Process of Building DSS

DSS is a computerized system for helping makedecisions. A decision is a choice between alternativesbased on estimates of the values of those

alternatives. Supporting a decision means helpingpeople working alone or in a group gatherintelligence, generate alternatives and make choices.An interactive, flexible, and adaptable computer-based information system, especially developed for

supporting the solution of a non-structuredmanagement problem for improved decision making
http://en.wikipedia.org/wiki/Information_systemhttp://en.wikipedia.org/wiki/Managementhttp://en.wikipedia.org/wiki/Decision_makinghttp://en.wikipedia.org/wiki/Decision_makinghttp://en.wikipedia.org/wiki/Managementhttp://en.wikipedia.org/wiki/Information_system

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Classification

They are: Passive, active, and cooperative DSS.

A passive DSS is a system that aids theprocess of decision making, but that cannotbring out explicit decision suggestions orsolutions.

An active DSS can bring out such decisionsuggestions or solutions

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Classification

A cooperative DSS allows the decisionmaker (or its advisor) to modify,

complete, or refine the decisionsuggestions provided by the system,before sending them back to thesystem for validation. The system again

improves, completes, and refines thesuggestions of the decision maker andsends them back to her for validation

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Classification DSS

Amodel-driven DSS emphasizes accessto and manipulation of a statistical,

financial, optimization, or simulationmodel. Model-driven DSS use data andparameters provided by users to assist

decision makers in analyzing asituation; they are not necessarily dataintensive

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Classification DSS

Acommunication-driven DSSsupports more than one person working

on a shared task; examples includeintegrated tools like Microsoft'sNetMeeting or Groove.

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Classification DSS

Adata-driven DSS or data-orientedDSS emphasizes access to and

manipulation of a time series of internalcompany data and, sometimes, externaldata
http://en.wikipedia.org/wiki/Time_serieshttp://en.wikipedia.org/wiki/Time_series

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Classification DSS

Adocument-driven DSS manages,retrieves and manipulates unstructured

information in a variety of electronicformats.

Aknowledge-driven DSS provides

specialized problem solving expertisestored as facts, rules, procedures, or insimilar structures.
http://en.wikipedia.org/wiki/Problem_solvinghttp://en.wikipedia.org/wiki/Problem_solving

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Computer system at management levelof the organisation that combines data,

sophisticated analytical models and userfriendly software to support semistructured and unstructured decision

making

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DSS Components

DSS database a collection of currentor historical data from a no: of

applications or groups organised foreasy access by a range of applications

DSS model base a collection of

mathematical and analytical models thatcan easily be made accessible to DSSuser

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DSS Components

DSS software permits easy interactionbetween the user and database and the

model base

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Characteristics of DSS

Support semi structured andunstructured problem analysis

Incorporate the data of TPS/MIS andthe models of OR

Used at many levels of the organisation

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Core DSS Capabilities

Representation

Operation

Memory Aids

Control Aids

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DSS Classes

Model driven DSS

Primarily stand alone system that uses

some type of model to perform analysis Data driven DSS

A system that supports decision making by

allowing users to extract and analyzeuseful information that was previouslyburied in large databases

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DSS Classes

Customer decision support system

System to support the decision making

process of an existing or potentialcustomer

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Group DSS

An interactive computer based systemto facilitate the solution to a problem by

a set of decision makers workingtogether as a group

Components

Hardware Software

People

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Group DSS

Hardware Conference facility, display boards, audio

visual aids, computer, networkingequipment etc

Software Electronic brainstorming tools,

questionnaires, idea organizers, tools forvoting and setting priorities, stakeholderidentification and analysis, groupdictionaries

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Group DSS

People

Participants, facilitators etc

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GDSS Advantages

Guaranteeing contributors anonymity

Attendees can evaluate their own ideas

Attendees can contribute without fear

Structured methods for organizing andevaluating ideas

Easy documentation

Increase the no: of ideas, thus thequality of decisions

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DATABASE MANAGEMENT SYSTEM

Understand the importance of Data Base inan organization.

Examine the functions of DBMS. Analyze the presence of Data Structure

Link various data types.

Classify the DBMS types.

Understand the functioning of SystemAnalysis and Design.

Use of DFD

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A database management system (DBMS) iscomputer software designed for the purpose

of managing databases. Typical examples ofDBMSs include Oracle, DB2, MicrosoftAccess, Microsoft SQL Server. A DBMS is acomplex set of software programs that

controls the organization, storage,management, and retrieval of data in adatabase.
http://en.wikipedia.org/wiki/Computer_softwarehttp://en.wikipedia.org/wiki/Databasehttp://en.wikipedia.org/wiki/Oracle_databasehttp://en.wikipedia.org/wiki/IBM_DB2http://en.wikipedia.org/wiki/Microsoft_Accesshttp://en.wikipedia.org/wiki/Microsoft_Accesshttp://en.wikipedia.org/wiki/Microsoft_SQL_Serverhttp://en.wikipedia.org/wiki/Sethttp://en.wikipedia.org/wiki/Software_programhttp://en.wikipedia.org/wiki/Organizationhttp://en.wikipedia.org/wiki/Computer_storagehttp://en.wikipedia.org/wiki/Information_retrievalhttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Databasehttp://en.wikipedia.org/wiki/Databasehttp://en.wikipedia.org/wiki/Datahttp://en.wikipedia.org/wiki/Information_retrievalhttp://en.wikipedia.org/wiki/Computer_storagehttp://en.wikipedia.org/wiki/Organizationhttp://en.wikipedia.org/wiki/Software_programhttp://en.wikipedia.org/wiki/Sethttp://en.wikipedia.org/wiki/Microsoft_SQL_Serverhttp://en.wikipedia.org/wiki/Microsoft_Accesshttp://en.wikipedia.org/wiki/Microsoft_Accesshttp://en.wikipedia.org/wiki/IBM_DB2http://en.wikipedia.org/wiki/Oracle_databasehttp://en.wikipedia.org/wiki/Databasehttp://en.wikipedia.org/wiki/Computer_software

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A DBMS includes:

Amodelinglanguage to define the schema

of each database hosted in the DBMS,according to the DBMS data model.

The four most common types of organizationsare the hierarchical, network, relational and

object models. Inverted lists and othermethods are also used. A given databasemanagement system may provide one ormore of the four models.
http://en.wikipedia.org/wiki/Data_modelinghttp://en.wikipedia.org/wiki/Formal_languagehttp://en.wikipedia.org/wiki/Logical_schemahttp://en.wikipedia.org/wiki/Databasehttp://en.wikipedia.org/wiki/Data_modelhttp://en.wikipedia.org/wiki/Hierarchical_modelhttp://en.wikipedia.org/wiki/Network_modelhttp://en.wikipedia.org/wiki/Relational_modelhttp://en.wikipedia.org/wiki/Hierarchical_modelhttp://en.wikipedia.org/wiki/Network_modelhttp://en.wikipedia.org/wiki/Relational_modelhttp://en.wikipedia.org/wiki/Object_modelhttp://en.wikipedia.org/wiki/Object_modelhttp://en.wikipedia.org/wiki/Relational_modelhttp://en.wikipedia.org/wiki/Network_modelhttp://en.wikipedia.org/wiki/Hierarchical_modelhttp://en.wikipedia.org/wiki/Data_modelhttp://en.wikipedia.org/wiki/Databasehttp://en.wikipedia.org/wiki/Logical_schemahttp://en.wikipedia.org/wiki/Formal_languagehttp://en.wikipedia.org/wiki/Data_modeling

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The dominant model in use today is thead hoc one embedded in SQL, despite

the objections of purists who believethis model is a corruption of therelational model, since it violates

several of its fundamental principles forthe sake of practicality andperformance.
http://en.wikipedia.org/wiki/SQLhttp://en.wikipedia.org/wiki/SQL

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Data structures (fields, records, files andobjects) optimized to deal with very largeamounts of data stored on a permanentdata

storage device. Adatabase query language and report

writer to allow users to interactivelyinterrogate the database, analyze its data andupdate it according to the users privileges ondata.

Atransaction mechanism.
http://en.wikipedia.org/wiki/Data_structurehttp://en.wikipedia.org/wiki/Digital_permanencehttp://en.wikipedia.org/wiki/Data_storage_devicehttp://en.wikipedia.org/wiki/Digital_permanencehttp://en.wikipedia.org/wiki/Data_storage_devicehttp://en.wikipedia.org/wiki/Data_storage_devicehttp://en.wikipedia.org/wiki/Database_query_languagehttp://en.wikipedia.org/wiki/Privilege_(Computing)http://en.wikipedia.org/wiki/Database_transactionhttp://en.wikipedia.org/wiki/Database_transactionhttp://en.wikipedia.org/wiki/Privilege_(Computing)http://en.wikipedia.org/wiki/Database_query_languagehttp://en.wikipedia.org/wiki/Data_storage_devicehttp://en.wikipedia.org/wiki/Data_storage_devicehttp://en.wikipedia.org/wiki/Digital_permanencehttp://en.wikipedia.org/wiki/Data_structure

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Features and Abilities of DBMS

One can characterize a DBMS as an "attributemanagement system" where attributes aresmall chunks of information that describesomething.DBMS roll together frequently-neededservices or features of attribute management.This allows one to get powerful functionality"out of the box" rather than program eachfrom scratch or add and integrate themincrementally

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Advantages of Data Base ManagementSystem

A database query language and report writerto allow users to interactively interrogate thedatabase, analyze its data and update itaccording to the users privileges on data.

It also controls the security of the database.Data security prevents unauthorized usersfrom viewing or updating the database

Using passwords, users are allowed accessto the entire database or subsets of it calledsub schemas

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Advantages of Data BaseManagement System

Backup and replication

Copies of attributes need to be made

regularly in case primary disks or otherequipment fails. A periodic copy of attributesmay also be created for a distant organization

that cannot readily access the original.

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Rule enforcement

Often one wants to apply rules to

attributes so that the attributes areclean and reliable

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Security

Often it is desirable to limit who can see

or change which attributes or groups ofattributes. This may be manageddirectly by individual, or by the

assignment of individuals and privilegesto groups.

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Computation

There are common computations

requested on attributes such ascounting, summing, averaging, sorting,grouping, cross-referencing, etc.

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Change and access logging

Often one wants to know who accessed

what attributes, what was changed, andwhen it was changed. Logging servicesallow this by keeping a record of access

occurrences and changes.

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Physical view of Data

Physical Views is a pattern that shows

how to encapsulate a physical databaseso that it can be easily accessed andoptimized without affecting upper layers

of software.

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Data Flow Diagram

Adata flow diagram (DFD) is a

graphical representation of the "flow" of

data through an information system. Adata flow diagram can also be used forthe visualization ofdata processing.

Data flow diagrams (DFDs) are one of thethree essential perspectives ofStructured Systems Analysis
http://en.wikipedia.org/wiki/Information_systemhttp://en.wikipedia.org/wiki/Visualizationhttp://en.wikipedia.org/wiki/Data_processinghttp://en.wikipedia.org/wiki/Data_processinghttp://en.wikipedia.org/wiki/Visualizationhttp://en.wikipedia.org/wiki/Information_system

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Data Flow Diagram

Dataflow diagrams can be used toprovide the end user with a physical

idea of where the data they inputultimately has an effect upon thestructure of the whole system from

order to dispatch to restock how anysystem is developed can be determinedthrough a dataflow diagram.

Developing a DFD: Top-Down

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e e op g a : op oApproach

The system designer makes a contextlevel DFD, which shows the interaction

(data flows) between the system(represented by one process) and thesystem environment (represented by

terminators).

Developing a DFD: Top-Down

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p g pApproach

The system is decomposed in lower levelDFD (Zero) into a set of processes, datastores, and the data flows between these

processes and data stores. Each process is then decomposed into an

even lower level diagram containing itssubprocesses.

This approach then continues on thesubsequent subprocesses, until a necessaryand sufficient level of detail is reachedwhich is called the primitive process.

E t P titi i A h t

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Event Partitioning Approach toDFD

Construct detailed DFD.

The list of all events is made.

For each event a process is constructed. Each process is linked (with incoming data

flows) directly with other processes or viadatastores, so that it has enough information torespond to a given event.

The reaction of each process to a given event ismodeled by an outgoing data flow.

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Data Structure

A collection of data with the best proceduralrepresentation is called data structure. Thechoice of the data structure often begins from

the choice of an abstract data type. A well-designed data structure allows a variety ofcritical operations to be performed, using asfew resources, both execution time andmemory space, as possible. Data structures

are implemented using the data types,references and operations on them providedby a programming language.

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Common data structures

Array

Stacks

Queues

Linked lists

Trees

Graphs

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ARRAY

In most programming languages eachelement has the same data type and

the array occupies a contiguous area ofstorage. Most programming languageshave a built-in array data type.

Multi-dimensional arrays are accessedusing more than one index: one foreach dimension

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STACK

A stack is a temporary abstract data type anddata structure based on the principle of Last

In First Out (LIFO,).Stacks are used extensively at every level of a

modern computer system. For example, amodern PC uses stacks at the architecture

level, which are used in the basic design ofan operating system for interrupt handlingand operating system function calls.

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STACK

A stack-based computer system is onethat stores temporary information

primarily in stacks, rather thanhardware CPU registers (a register-based computer system).

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QUEUE

A queue is a particular kind of collectionin which the entities in the collection

are kept in order and the principal (oronly) operations on the collection arethe addition of entities to the rear

terminal position and removal of entitiesfrom the front terminal position.

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QUEUE

Queues provide services in computerscience, transport and operations

research where various entities such asdata, objects, persons, or events arestored and held to be processed later.

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LINKED LIST

A linked list is one of the fundamentaldata structures, and can be used to

implement other data structures. Itconsists of a sequence of nodes, eachcontaining arbitrary data fields and one

or two references (links) pointing tothe next and/or previous nodes.

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LINKED LIST

The principal benefit of a linked list overa conventional array is that the order of

the linked items may be different fromthe order that the data items are storedin memory or on disk, allowing the list

of items to be traversed in a differentorder

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TREE

Tree is a widely-used data structure thatemulates a tree structure with a set of

linked nodes. A node may contain avalue or a condition or represents aseparate data structure or a tree of its

own.

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GRAPH

A graph is a kind of data structure,specifically an abstract data type (ADT),

that consists of a set of nodes and a setof edges that establish relationships(connections) between the nodes.

D t b M t (DBM)

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Database Management (DBM)

The Database Management Layer allowsscript programmers to store information

as a pair of strings; a key, which is usedto find the associated value. Essentially,a DBM adds more functionality and

better sorting during storage to thebinary flat-files that it uses.

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Relational

The relational databases such as SQL,Microsoft SQL Server and Oracle, have

a much more logical structure in theway that it stores data. Tables can beused to represent real world objects,

with each field acting like an attribute.

Type of Database

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Type of Database

Databases have been in use since theearliest days of electronic computing.

Unlike modern systems which can beapplied to widely different databasesand needs, the vast majority of older

systems were tightly linked to thecustom databases in order to gainspeed at the expense of flexibility.

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Introduction to System Analysis

and DesignSystems are created to solve problems.

The subject System Analysis and Design,mainly deals with the softwaredevelopment activities.

I t d ti t S t A l i

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Introduction to System Analysisand Design

understand a system

understand the different phases of

system developments life cycle know the components of system

analysis

know the components of systemdesigning

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Defining A System

A collection of components that worktogether to realize some objective

forms a system. Basically there arethree major components in everysystem, namely input, processing andoutput.

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Defining A System

Input Processing Output

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SYSTEM LIFE CYCLE

System life cycle is an organizationalprocess of developing and maintaining

systems. It helps in establishing asystem project plan, because it givesoverall list of processes and sub-

processes required developing asystem.

Phases of software development

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Phases of software development

cycle

System study

Feasibility study

System analysis System design

Coding

Testing Implementation

Maintenance

Ph f f d l

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Phases of software developmentcycle

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PHASES OF SYSTEM DEVELOPMENTLIFE CYCLE

System Study

System study is the first stage of systemdevelopment life cycle. This gives a clear picture of

physical system. In practice, the system study isdone in two phases. In the first phase, thepreliminary survey of the system is done which helpsin identifying the scope of the system. The secondphase of the system study is more detailed and in-

depth study in which the identification of usersrequirement and the limitations and problems of thepresent system are studied.

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To describe the system study phase moreanalytically..

Problem identification and projectinitiation

Background analysis

Inference or findings

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Feasibility Study

On the basis of result of the initial study,feasibility study takes place. The

feasibility study is basically the test ofthe proposed system in the light of itsworkability, meeting users

requirements, effective use ofresources.

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Feasibility Study

The main goal of feasibility study is notto solve the problem but to achieve the

scope. In the process of feasibilitystudy, the cost and benefits areestimated with greater accuracy.

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System Analysis

Assuming that a new system is to bedeveloped, the next phase is system

analysis. Analysis involved a detailedstudy of the current system, leading tospecifications of a new system..

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System Analysis

Analysis is a detailed study of variousoperations performed by a system and

their relationships within and outsidethe system. During analysis, data arecollected on the available files, decision

points and transactions handled by thepresent system

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System Design

Based on the user requirements and thedetailed analysis of a new system, the

new system must be designed. This isthe phase of system designing.

The design proceeds in two stages :

preliminary or general design structure or detailed design

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Tools and techniques used for designing

Flowchart

Data flow diagram (DFDs)

Data dictionary

Structured English

Decision table

Decision tree

St t d S t A l i d

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Structured Systems Analysis andDesign Method (SSADM)

SSADM is one particular implementationand builds on the work of different

schools of development methods, someof the key members of which included.

Logical data design

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Logical data design

Also known as the logical systemspecification stage. In this stage,

technically feasible options are chosen.The development/implementationenvironments are specified based on

this choice.

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Logical data design

Define BSOs (Business Systems Options). Itspurpose is to identify and define the possibleapproaches to the physical implementation to

meet the function definitions. It also validatesthe service level requirements for theproposed system in the light of the technicalenvironment.

Select BSO. This step is concerned with thepresentation of the BSOs to users and theselection of the preferred option.

Logical process design

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Logical process design

Define user dialogue. This step defines the structureof each dialogue required to support the on-linefunctions and identifies the navigation requirements,both within the dialogue and between dialogues.

Define update processes. This is to complete thespecification of the database updating required foreach event and to define the error handling for eachevent.

Define enquiry processes. This is to complete thespecification of the database enquiry processing andto define the error handling for each enquiry

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Physical design

The following activities are part of this stage: Prepare for physical design Learn the rules of the implementation

environment Review the precise requirements for logical to

physical mapping Plan the approach Complete the specification of functions Incrementally and repeatedly develop the

data and process designs

MIS 2 & 3

Documents

Transcript of MIS 2 & 3