lecture04 by dandanhuanghuang

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									Information Systems 2nd edition
A Business Approach


Business
Information
Systems
       Information Systems – A Business
       Approach, Steve Benson and Craig
                   Standing               1
Data, Information, Knowledge
and Wisdom

Level In                Data           Scope of tasks      Example
Organisation            Hierarchy
                        Position
Executive Level –       Wisdom         Being able to       Planning to abandon
highly                  (Why?)         apply knowledge     an unprofitable line
unstructured                                               and introduce a new
activities using                                           one.
highly abstract
information
Senior                  Knowledge      Understanding the   Analysing the trends
Management              (How?)         meaning of          shows that a
level – loosely                        information         particular line is no
structured tasks                                           longer profitable.
using condensed
information
Line management         Information    Data processed in   Summarised
level,                  (What?)        such a way as to    quarterly data
summarised data,                       reveal previously   expressed as in chart
fairly structured                      obscure trends.     form.
tasks
Operative level,        Data           Raw, unprocessed    e.g. daily cash
no summarised           (What?)        entries             entries in a
data, highly                                               spreadsheet relating
structured tasks                                           to sales lines.
                    Information Systems – A Business
                    Approach, Steve Benson and Craig
                                Standing                                           2
    What is a Transaction?

   A transaction is a group of instructions that
    is indivisible or ‘atomic’ in that it either
    executes completely or fails completely.
   In the event of partial execution,
    instructions must be ‘undone’.
   A transaction is not complete until it is
    ‘committed’ onto stable storage – this gives
    a tradeoff between high performance and
    high reliability – TPSs have to be reliable!

             Information Systems – A Business
             Approach, Steve Benson and Craig
                         Standing               3
    Transaction Processing Systems
   TPSs are the backbone of IS, well-
    established systems.
   TPSs come in two main flavours, batch
    and real time.
   Batch Systems store up transaction data
    for later processing, e.g. telephone bills.
   Real Time Systems perform transactions
    as they arrive, e.g. reservation systems.
   Why do we need to record transactions?


             Information Systems – A Business
             Approach, Steve Benson and Craig
                         Standing                 4
    Examples TPSs

   Point of Sale Systems (POS), e.g. a
    supermarket – usually purchased as a
    turnkey system.
   Order Entry Systems – has POS functionality
    plus billing and shipping addresses, different
    inputs (EDI, WWW) – greater potential for
    error than a POS.
   Reservation Systems, e.g. airline and hotel
   General Ledger – some contention about
    whether general ledger qualifies as TPS –
    most financial systems have the general
    ledger systems as their confluence.
              Information Systems – A Business
              Approach, Steve Benson and Craig
                          Standing               5
    Databases

   While TPSs provide the means of effecting
    transactions, transactions are usually
    recorded in a database.
   A database is a logically related collection
    of organised data.
   We make a distinction between data and
    metadata
   Database management systems (DBMS)
    carry out: Data storage and retrieval,
    Transaction/update atomicity, user
    authentication and security, elimination of
    redundant data – update once and once
    only
             Information Systems – A Business
             Approach, Steve Benson and Craig
                         Standing               6
Data Hierarchy

   Database
   Files may be integrated
    into databases.                           Increasing
   Records are grouped                       abstraction
    into files.
   Fields are grouped into
    records.
   Bytes are grouped into
    fields.
   Bits are grouped into
    bytes.

           Information Systems – A Business
           Approach, Steve Benson and Craig
                       Standing                             7
Database Organisation
   There are three main methods:
       Hierarchical – older but excellent for well-
        defined applications – not very flexible.
       Network – has a high degree of flexibility but
        can be very hard to manage for complex
        applications.
       Relational – more recent, good compromise,
        uses SQL, very adaptable, data are
        independent of software.
   Even though the relational model is
    ‘best’ there are many older databases
    still in use.
   Object-oriented databases are the next
    stage of database development.
               Information Systems – A Business
               Approach, Steve Benson and Craig
                           Standing                      8
Management Information
Systems (MIS)

   Five basic types
       Management Reporting Systems (MRS)

       Decision Support Systems (DSS)

       Expert Systems (ES)

       Executive Information Systems (EIS)

       Groupware



               Information Systems – A Business
               Approach, Steve Benson and Craig
                           Standing               9
Types of MRS Report
Report Type      Management Level       Report Content
Summary          Medium/High levels     Usually statistical, time series
                                        information - giving an analysis of the
                                        underlying data. Generally speaking
                                        the higher the management level the
                                        more summarised the data.
                                        Transactional analysis would be quite
                                        common.
Exception        All levels             Only data/information that falls
Reports                                 outside the expected range is
                                        presented in the report.e.g. An
                                        excessive number of orders placed by
                                        a customer who has not paid a bill
                                        recently, an unacceptably high failure
                                        rate in manufacture etc.
Detail Reports   Usually Lower          These tend to be used at the
                 levels - sometimes     operational level, the period the report
                 higher management      covers might be, hourly, daily or
                 when summary           weekly depending on the nature of the
                 reports are too        business. We might wish to review the
                 coarse grained to      efficiency of sales staff in a
                 provide them with      department store, or be able to link
                 the information that   manufacturing problems to the
                 they need to solve a   replacement of tools from a certain
                 problem.               supplier etc.
                 Information Systems – A Business
                 Approach, Steve Benson and Craig
                             Standing                                          10
Decision Support Systems

   Use data from the past, from internal such
    as databases, data warehouses and
    datamarts or external sources to model
    possible futures.
   E.g. to assess the impact in cases where
    an employee is dismissed.
   When using a data warehouse, data-
    mining and OLAP tools are needed – e.g.
    to establish most valuable customers.

            Information Systems – A Business
            Approach, Steve Benson and Craig
                        Standing               11
Expert Systems
   These are intended to mimic human
    expertise in a specialised area. Many
    domain experts may contribute to such
    systems.
   ESs run 24 hrs per day and do not get
    tired.
   They consist of: knowledge base,
    inference engine and user interface.
   They tend to be used to augment rather
    than replace the human element.
   Example systems include, aircraft docking,
    shipping systems, subway navigation
             Information Systems – A Business

    systems.
             Approach, Steve Benson and Craig
                         Standing             12
Executive Information Systems
   Executive Information Systems (EIS) tend
    to have an enterprise wide focus and make
    extensive use of external data. They
    resemble DSSs, but emphasise data
    synthesis, display; trend and cause
    analysis rather than modelling which is the
    focus of most DSSs. EISs make use of hard
    and soft data, and allow human browsing
    without making queries.
   Most EISs are slow in operation because
    they use relational databases for complex
    queries, some may need to carry out
    environmental sensing.
   EISs frequently use groupware.
            Information Systems – A Business
            Approach, Steve Benson and Craig
                        Standing               13
Groupware




   Groupware has four main functional
    areas in relation to information

           Information Systems – A Business
           Approach, Steve Benson and Craig
                       Standing               14
Groupware

   Communications may be:
      Synchronous (real time – voice, video,
       etc.)
      Asynchronous (via a bulletin board)
      1:1, 1:N or M:N
   Groupware is more of an environment than
    a product. It is the enabling technology for
    Group DSS and knowledge management.
   When combined with technologies such as
    intelligent agents it can simplify project
    and other management.
   Potentially very high return on investment.
            Information Systems – A Business
            Approach, Steve Benson and Craig
                        Standing               15
Groupware Problems

   Information overload
   Inappropriate sharing of information
   Time wasting – since it easy to arrange
    meetings, staff tend to do so.
   State tracking – if staff do not update
    their electronic diary, meetings are
    arranged and they cannot attend.
   Poor implementation strategies.


           Information Systems – A Business
           Approach, Steve Benson and Craig
                       Standing               16
    Summary

   All ISs can be categorised according to the
    level at which they operate.
   Low-level applications are well defined and
    structured and easy to automate (the
    systems replace people).
   High-level applications tend to be
    unstructured and are difficult to automate
    (the systems tend to complement people).
   It is usually more cost effective to let
    people provide the intelligence and
    computers provide the efficiency.

             Information Systems – A Business
             Approach, Steve Benson and Craig
                         Standing               17
Information Systems – A Business
Approach, Steve Benson and Craig
            Standing               18

								
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