Systems analysis
The system analysis is a practically applicable method of system theory. The viewer of the system a model of an existing or planned system initially designed as a black box and refine this later on. In this case, the processor has to make a choice with respect to the relevant elements and relations of the system. The model created is - especially for complex systems - usually a limited, reduced, abstracted depiction of reality, by which statements about past and future trends and behaviors of the system are to be made in certain scenarios. The process is applicable to almost any system, including physics, biology, demography, economics, geography, technology and computer science.
Steps
Representation
Representation of the analysis results:
- Qualitative: concept map, flow chart, action diagrams
- Semiquantitatively: Arrow diagram ( each more relationships)
- Quantitatively: xy, xt - diagrams, among others, mathematical equations
Formal and graphical methods are used for the system analysis.
Keith Edwards makes do in his work with the following elements in order to represent various model systems:
- DFD (Data Flow Diagram): data flow diagram represents the processing and storage of data streams
- STD ( State Transition Diagram): state transition diagram shows temporal behavior.
- ERD ( Entity Relationship Diagram ): an object - relationship diagram represents, data links dar. each other
- ESTD (Entity State Diagram ): object state diagram, as a mixed form of STD and ERD. Displays status changes as a function of temporal events.
Furthermore, he is quick to identify the following theoretically possible combinations, but which are in practice only very limited useful:
- Mapping between data stream display and data storage ( for verification ).
- Temporal changes of data processing by control signals ( for function ).
The derivation of states ( " states" ) by events ( "Events" ) and vice versa is possible. A permanent limit to a reasonable level of detail for each item set is needed to arrive at a suitable, that is inscrutable and thus usable result. The presentation differs between control currents, streams, instantaneous events and physical flows of matter or energy.
Examples
Computer science
Subsystem analysis is understood in the design process of computer science in the first phase. The systems analyst describes the relevant question for his system elements and their relationships to each other (usually with an information model). Goal of systems analysis is to describe, for example, the environment without machine ( actual state) to plan a machine based on this actual model. The target model shows how the machine is to look like. Due to the differences between actual and target model is clearly what is to afford to be constructed machine. As part of the system analysis is not investigated how the machine is implemented. As a machine are to be understood as a unit in this connection hardware and software. The analysis system can also be used prior to the optimization, migration and conversion systems.
Application system development
When creating application systems in the business context or in the adaptation of standard software ( " customizing" ), it may be useful to the relevant business processes to model ( for example, event-driven process chains [ EPK ] ). These models not only serve as a basis for planning organizational measures ( process management ), but are also suitable for requirements gathering for application systems to support business processes without media disruption and efficient through IT.