IMS1805 Systems Analysis Topic 1: Recap: The elements of analysis

2 Agenda Aim: To return to 10,000 ft and review where we have come in developing an understanding of systems analysis

The ubiquity of systems (it means they’re everywhere) Water supply systems Food supply systems A chocolate bar An orange A supermarket system A university department management system Health systems etc

4 Some characteristics of systems Purpose/area of interest Size Scope Elements: People/organisations/procedures/rules/ machines/etc Inter-connectedness

5 Fundamental purposes of ALL systems To establish and maintain control over the actions/events which the system supports Within this, many possible sub-objectives: To improve speed To reduce cost To reduce risk of failure To increase reliability To improve availability/access To make easier to use etc

6 Information in systems All systems involving people include the exchange of information as an element of the system Effective system functioning is usually dependent on how well the information component of the system is managed Therefore most human systems have specialist systems for managing their information elements

7 Information Systems The importance of information in systems led to the study of the information components of a system as a field in its own right – Information Systems Many aspects to information and therefore the diversity of the IS field Nature of information Use (and abuse) of information Classification and categorisation of information Technology for handling information etc

Analysis A fundamental human activity aimed at giving meaning to the events going on around us Formal vs informal analysis

9 The ubiquity of analysis Current events Weather Politics Crime Law Sport – cricket/football/racing/basketball/etc The arts – film/theatre/literature/art/dance/etc Fashion Technology Popular culture Etc, etc

10 The elements of analysis Observation Perception Interpretation/Comprehension/Explanation Representation

11 Analysis of systems System purpose/effects Objectives Outcomes Responses etc Systems components People Procedures Rules Machines/technology etc Component interactions Organisation/structure of components Control/influences between components Movement between components etc

12 Deciding how to do systems analysis What is the purpose of my analysis? What aspects of the system should I observe? What aspects of the system can I perceive? What forms of explanation can I develop? How can I represent the system?

13 Systems analysis for an information system The intangible nature of information and its processes/events/relationships The (unusual) characteristics of information and its importance to people involved in systems The subjectivity of data and information as system elements The variability of usage for information elements in an information system

Modelling and representation of systems We have looked at several different forms of modelling, each oriented around a different view of a real world Information System: Process modelling – functional decomposition or DFD Data modelling Soft systems modelling Object-oriented modelling Each offers a particular way of viewing an IS and explaining some aspect of how it operates

15 Abstraction/selection Models as simplifications of the real world Choosing what aspects of the real world need to be included in a model Choosing what aspects of the real world can be omitted from a model

16 Level of detail The limits of human comprehension – being unable to see the wood for the trees Choosing what level of detail is needed to convey a satisfactory understanding of the system Choosing how to simplify system elements to reduce the level of detail

17 Partitioning Dividing a system model into pieces: For manageability of detail For separation of uses Partitioning horizontally Partitioning vertically

18 Representation Deciding how to express/describe the system elements and their relationships Limits of available means for representing/describing things Problems with representing intangible things – information/information processes/relationships/etc

19 Purpose The purpose behind a model drives the form of model we choose Some possible purposes: Understanding (personal) Explanation (to others) Specification Documentation

20 Summary Learning to analyse = learning to think Need for practice Need for introspection and reflection Need for learning from others Applicable wherever you go and whatever you do