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decision support system

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decision support system

  1. 1. 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
  2. 2. Decision support systems: DefinitionsDecision support systems are a class ofcomputer-based information systemsincluding knowledge based systems thatsupport decision making activities.
  3. 3. Decision support systems There are many approaches to decision-making and because of the wide range of domains in which decisions are made, the concept of decision support system (DSS) is very broad. A DSS can take many different forms. DSS is a computerized system for helping to make decisions. A decision is a choice between alternatives based on estimates of the values of those alternatives. Supporting a decision means helping people working alone or in a group gather intelligence, generate alternatives and make choices.
  4. 4. Decision Making There are often confusion between terms MIS and information system. Information systems include systems that are not intended for decision making. MIS is referred to, in a restrictive sense, as information technology management
  5. 5. Framework for Developing DecisionSupport System A DSS is a system that aids the process of decision making, but that cannot bring out explicit decision suggestions or solutions. DSS can bring out such decision suggestions or solutions.
  6. 6. Framework for Developing DecisionSupport System DSS allows the decision maker (or its advisor) to modify, complete, or refine the decision suggestions provided by the system, before sending them back to the system for validation. The system again improves, completes, and refines the suggestions of the decision maker and sends them back to for validation.
  7. 7. Framework for Developing DecisionSupport System A model-driven DSS emphasizes access to and manipulation of a statistical, financial, optimization, or simulation model. Model-driven DSS use data and parameters provided by users to assist decision makers in analyzing a situation; they are not necessarily data intensive
  8. 8. Framework for Developing DecisionSupport System• A communication-driven DSS supports more than one person working on a shared task; examples include integrated tools like Microsofts Net Meeting or Groove.
  9. 9. Framework for Developing DecisionSupport System• A data-driven DSS or data-oriented DSS emphasizes access to and manipulation of a time series of internal company data and, sometimes, external data.
  10. 10. Framework for Developing Decision Support System• A document-driven DSS manages, retrieves and manipulates unstructured information in a variety of electronic formats.
  11. 11. Framework for Developing Decision Support System• A knowledge-driven DSS provides specialized problem solving expertise stored as facts, rules, procedures, or in similar structures.
  12. 12. 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 support system for medical diagnosis. Other examples include a bank loan officer verifying the credit of a loan applicant or an engineering firm that has bids on several projects and wants to know if they can be competitive with their costs.
  13. 13. Decision Support SystemDSS is extensively used in business andmanagement. Executive dashboard andother business performance software allowfaster decision making, identification ofnegative trends, and better allocation ofbusiness resources.
  14. 14. Decision Support System A growing area of DSS application, concepts, principles, and techniques is in agricultural production, marketing for sustainable development.
  15. 15. DSS characteristics and capabilities Support for decision makers in semi structured and unstructured 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
  16. 16. Process of Building DSS DSS is a computerized system for helping make decisions. A decision is a choice between alternatives based on estimates of the values of those alternatives. Supporting a decision means helping people working alone or in a group gather intelligence, generate alternatives and make choices. An interactive, flexible, and adaptable computer- based information system, especially developed for supporting the solution of a non-structured management problem for improved decision making
  17. 17. ClassificationThey are: Passive, active, and cooperative DSS. A passive DSS is a system that aids the process of decision making, but that cannot bring out explicit decision suggestions or solutions. An active DSS can bring out such decision suggestions or solutions
  18. 18. Classification A cooperative DSS allows the decision maker (or its advisor) to modify, complete, or refine the decision suggestions provided by the system, before sending them back to the system for validation. The system again improves, completes, and refines the suggestions of the decision maker and sends them back to her for validation
  19. 19. Classification DSSA model-driven DSS emphasizes access to and manipulation of a statistical, financial, optimization, or simulation model. Model-driven DSS use data and parameters provided by users to assist decision makers in analyzing a situation; they are not necessarily data intensive
  20. 20. Classification DSS• A communication-driven DSS supports more than one person working on a shared task; examples include integrated tools like Microsofts NetMeeting or Groove.
  21. 21. Classification DSS A data-driven DSS or data-oriented DSS emphasizes access to and manipulation of a time series of internal company data and, sometimes, external data
  22. 22. Classification DSS A document-driven DSS manages, retrieves and manipulates unstructured information in a variety of electronic formats. A knowledge-driven DSS provides specialized problem solving expertise stored as facts, rules, procedures, or in similar structures.
  23. 23. Decision Support System Computer system at management level of the organisation that combines data, sophisticated analytical models and user friendly software to support semi structured and unstructured decision making
  24. 24. DSS Components DSS database – a collection of current or historical data from a no: of applications or groups organised for easy access by a range of applications DSS model base – a collection of mathematical and analytical models that can easily be made accessible to DSS user
  25. 25. DSS Components DSS software permits easy interaction between the user and database and the model base
  26. 26. Characteristics of DSS Support semi structured and unstructured problem analysis Incorporate the data of TPS/MIS and the models of OR Used at many levels of the organisation
  27. 27. Core DSS Capabilities Representation Operation Memory Aids Control Aids
  28. 28. 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 analyze useful information that was previously buried in large databases
  29. 29. DSS Classes Customer decision support system  System to support the decision making process of an existing or potential customer
  30. 30. Group DSS An interactive computer based system to facilitate the solution to a problem by a set of decision makers working together as a group Components  Hardware  Software  People
  31. 31. Group DSS Hardware  Conference facility, display boards, audio visual aids, computer, networking equipment etc Software  Electronic brainstorming tools, questionnaires, idea organizers, tools for voting and setting priorities, stakeholder identification and analysis, group dictionaries
  32. 32. Group DSS People  Participants, facilitators etc
  33. 33. GDSS – Advantages Guaranteeing contributors anonymity Attendees can evaluate their own ideas Attendees can contribute without fear Structured methods for organizing and evaluating ideas Easy documentation Increase the no: of ideas, thus the quality of decisions
  34. 34. DATABASE MANAGEMENT SYSTEM Understand the importance of Data Base in an organization. Examine the functions of DBMS. Analyze the presence of Data Structure Link various data types. Classify the DBMS types. Understand the functioning of System Analysis and Design. Use of DFD
  35. 35. DATABASE MANAGEMENT SYSTEM A database management system (DBMS) is computer software designed for the purpose of managing databases. Typical examples of DBMSs include Oracle, DB2, Microsoft Access , Microsoft SQL Server. A DBMS is a complex set of software programs that controls the organization, storage, management, and retrieval of data in a database.
  36. 36. DATABASE MANAGEMENT SYSTEMA DBMS includes: A modeling language to define the schema of each database hosted in the DBMS, according to the DBMS data model. The four most common types of organizations are the hierarchical, network, relational and object models. Inverted lists and other methods are also used. A given database management system may provide one or more of the four models.
  37. 37. DATABASE MANAGEMENT SYSTEM The dominant model in use today is the ad hoc one embedded in SQL, despite the objections of purists who believe this model is a corruption of the relational model, since it violates several of its fundamental principles for the sake of practicality and performance.
  38. 38. DATABASE MANAGEMENT SYSTEM Data structures (fields, records, files and objects) optimized to deal with very large amounts of data stored on a permanent data storage device. A database query language and report writer to allow users to interactively interrogate the database, analyze its data and update it according to the users privileges on data. A transaction mechanism.
  39. 39. Features and Abilities of DBMS One can characterize a DBMS as an "attribute management system" where attributes are small chunks of information that describe something. DBMS roll together frequently-needed services or features of attribute management. This allows one to get powerful functionality "out of the box" rather than program each from scratch or add and integrate them incrementally
  40. 40. Advantages of Data Base ManagementSystem A database query language and report writer to allow users to interactively interrogate the database, analyze its data and update it according to the users privileges on data. It also controls the security of the database. Data security prevents unauthorized users from viewing or updating the database Using passwords, users are allowed access to the entire database or subsets of it called sub schemas
  41. 41. Advantages of Data BaseManagement SystemBackup and replication Copies of attributes need to be made regularly in case primary disks or other equipment fails. A periodic copy of attributes may also be created for a distant organization that cannot readily access the original.
  42. 42. Advantages of Data BaseManagement SystemRule enforcement Often one wants to apply rules to attributes so that the attributes are clean and reliable
  43. 43. Advantages of Data BaseManagement SystemSecurity Often it is desirable to limit who can see or change which attributes or groups of attributes. This may be managed directly by individual, or by the assignment of individuals and privileges to groups.
  44. 44. Advantages of Data BaseManagement SystemComputation There are common computations requested on attributes such as counting, summing, averaging, sorting, grouping, cross-referencing, etc.
  45. 45. Advantages of Data BaseManagement SystemChange and access logging Often one wants to know who accessed what attributes, what was changed, and when it was changed. Logging services allow this by keeping a record of access occurrences and changes.
  46. 46. Advantages of Data BaseManagement SystemPhysical view of Data Physical Views is a pattern that shows how to encapsulate a physical database so that it can be easily accessed and optimized without affecting upper layers of software.
  47. 47. Data Flow DiagramA data flow diagram (DFD) is a graphical representation of the "flow" of data through an information system. A data flow diagram can also be used for the visualization of data processing.Data flow diagrams (DFDs) are one of the three essential perspectives of Structured Systems Analysis
  48. 48. Data Flow DiagramDataflow diagrams can be used toprovide the end user with a physicalidea of where the data they inputultimately has an effect upon thestructure of the whole system fromorder to dispatch to restock how anysystem is developed can be determinedthrough a dataflow diagram.
  49. 49. Developing a DFD: Top-DownApproach The system designer makes a context level DFD, which shows the interaction (data flows) between the system (represented by one process) and the system environment (represented by terminators).
  50. 50. Developing a DFD: Top-DownApproach The system is decomposed in lower level DFD (Zero) into a set of processes, data stores, and the data flows between these processes and data stores. Each process is then decomposed into an even lower level diagram containing its subprocesses. This approach then continues on the subsequent subprocesses, until a necessary and sufficient level of detail is reached which is called the primitive process.
  51. 51. Event Partitioning Approach toDFDConstruct 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 via datastores, so that it has enough information to respond to a given event.  The reaction of each process to a given event is modeled by an outgoing data flow.
  52. 52. Data StructureA collection of data with the best procedural representation is called data structure. The choice of the data structure often begins from the choice of an abstract data type. A well- designed data structure allows a variety of critical operations to be performed, using as few resources, both execution time and memory space, as possible. Data structures are implemented using the data types, references and operations on them provided by a programming language.
  53. 53. Common data structures Array Stacks Queues Linked lists Trees Graphs
  54. 54. ARRAYIn most programming languages each element has the same data type and the array occupies a contiguous area of storage. Most programming languages have a built-in array data type.Multi-dimensional arrays are accessed using more than one index: one for each dimension
  55. 55. STACKA stack is a temporary abstract data type and data 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, a modern PC uses stacks at the architecture level, which are used in the basic design of an operating system for interrupt handling and operating system function calls.
  56. 56. STACKA stack-based computer system is one that stores temporary information primarily in stacks, rather than hardware CPU registers (a register- based computer system).
  57. 57. QUEUEA queue is a particular kind of collectionin which the entities in the collectionare kept in order and the principal (oronly) operations on the collection arethe addition of entities to the rearterminal position and removal of entitiesfrom the front terminal position.
  58. 58. QUEUEQueues provide services in computer science, transport and operations research where various entities such as data, objects, persons, or events are stored and held to be processed later.
  59. 59. LINKED LISTA linked list is one of the fundamentaldata structures, and can be used toimplement other data structures. Itconsists of a sequence of nodes, eachcontaining arbitrary data fields and oneor two references (“links”) pointing tothe next and/or previous nodes.
  60. 60. LINKED LISTThe principal benefit of a linked list overa conventional array is that the order ofthe linked items may be different fromthe order that the data items are storedin memory or on disk, allowing the listof items to be traversed in a differentorder
  61. 61. TREETree is a widely-used data structure that emulates a tree structure with a set of linked nodes. A node may contain a value or a condition or represents a separate data structure or a tree of its own.
  62. 62. GRAPHA 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.
  63. 63. Database Management (DBM) The Database Management Layer allows script programmers to store information as a pair of strings; a key, which is used to find the associated value. Essentially, a DBM adds more functionality and better sorting during storage to the binary flat-files that it uses.
  64. 64. Relational The relational databases such as SQL, Microsoft SQL Server and Oracle, have a much more logical structure in the way that it stores data. Tables can be used to represent real world objects, with each field acting like an attribute.
  65. 65. Type of Database Databases have been in use since the earliest days of electronic computing. Unlike modern systems which can be applied to widely different databases and needs, the vast majority of older systems were tightly linked to the custom databases in order to gain speed at the expense of flexibility.
  66. 66. Introduction to System Analysisand Design Systems are created to solve problems. The subject System Analysis and Design, mainly deals with the software development activities.
  67. 67. 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 system designing
  68. 68. Defining A SystemA collection of components that work together to realize some objective forms a system. Basically there are three major components in every system, namely input, processing and output.
  69. 69. Defining A SystemInput  Processing  Output
  70. 70. SYSTEM LIFE CYCLE System life cycle is an organizational process of developing and maintaining systems. It helps in establishing a system project plan, because it gives overall list of processes and sub- processes required developing a system.
  71. 71. Phases of software developmentcycle System study Feasibility study System analysis System design Coding Testing Implementation Maintenance
  72. 72. Phases of software developmentcycle
  73. 73. PHASES OF SYSTEM DEVELOPMENTLIFE CYCLESystem Study System study is the first stage of system development life cycle. This gives a clear picture of physical system. In practice, the system study is done in two phases. In the first phase, the preliminary survey of the system is done which helps in identifying the scope of the system. The second phase of the system study is more detailed and in- depth study in which the identification of user’s requirement and the limitations and problems of the present system are studied.
  74. 74. To describe the system study phase moreanalytically….. Problem identification and project initiation Background analysis Inference or findings
  75. 75. Feasibility StudyOn the basis of result of the initial study, feasibility study takes place. The feasibility study is basically the test of the proposed system in the light of its workability, meeting user’s requirements, effective use of resources.
  76. 76. Feasibility Study The main goal of feasibility study is not to solve the problem but to achieve the scope. In the process of feasibility study, the cost and benefits are estimated with greater accuracy.
  77. 77. System Analysis Assuming that a new system is to be developed, the next phase is system analysis. Analysis involved a detailed study of the current system, leading to specifications of a new system..
  78. 78. System Analysis Analysis is a detailed study of various operations performed by a system and their relationships within and outside the system. During analysis, data are collected on the available files, decision points and transactions handled by the present system
  79. 79. System Design Based on the user requirements and the detailed analysis of a new system, the new system must be designed. This is the phase of system designing.The design proceeds in two stages : preliminary or general design structure or detailed design
  80. 80. Tools and techniques used for designing Flowchart Data flow diagram (DFDs) Data dictionary Structured English Decision table Decision tree
  81. 81. Structured Systems Analysis and Design Method (SSADM)SSADM is one particular implementationand builds on the work of differentschools of development methods, someof the key members of which included.
  82. 82. Logical data design Also known as the logical system specification stage. In this stage, technically feasible options are chosen. The development/implementation environments are specified based on this choice.
  83. 83. Logical data design Define BSOs (Business Systems Options). Its purpose is to identify and define the possible approaches to the physical implementation to meet the function definitions. It also validates the service level requirements for the proposed system in the light of the technical environment. Select BSO. This step is concerned with the presentation of the BSOs to users and the selection of the preferred option.
  84. 84. Logical process design Define user dialogue. This step defines the structure of each dialogue required to support the on-line functions and identifies the navigation requirements, both within the dialogue and between dialogues. Define update processes. This is to complete the specification of the database updating required for each event and to define the error handling for each event. Define enquiry processes. This is to complete the specification of the database enquiry processing and to define the error handling for each enquiry
  85. 85. Physical designThe 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

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