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SSD19 - Simulating Timing Behavior  

  LSE19 - Zeitverhalten simulieren

Contents  
  • 1 Allocation to V-Model and Methods Allocation
  • 2 Brief Characteristics
  • 3 Requirements
  •       3.1 Requirements for Interfaces
  •       3.2 Requirements for the Methods Support
  •       3.3 Requirements for Functions
  •       3.4 Other Requirements
  • 1 Allocation to V-Model and Methods Allocation

    V-Model

    SD2.3 - Investigation of Feasibility

  • System Architecture.Feasibility Studies
  • SD5.2 - Analysis of Resources and Time Requirements

  • SW Design (Module).Characteristic Quantities
  • SW Design (Database).Characteristic Quantities
  • Method

    SIMU - Simulation Models

    2 Brief Characteristics

    This service unit defines the requirements for tools used to simulate processes on a computer system that cannot be actually realized based on time, cost, and other reasons. This not only includes the simulation of airplane control but also the simulation of software during planning phases the way it is expressed in

    The simulation of software requires that actual data are available about:

    The following must be known with regard to the simulated computer system:

    When simulating real-time software systems it is also required to take into consideration the peripheral devices and their corresponding reaction times as well as the input and reaction time for user input.

    3 Requirements

    3.1 Requirements for Interfaces

    SSD19.I.1 Granularity The exchange of control parameters with SWFM01 - Workflow Management is possible for individual closed function packages of the tool by means of a disclosed, documented interface.
    SSD19.I.2 Input interface to SSD02 - Supporting Specification of User Interfaces It is possible to integrate interface specifications generated with SSD02 without further transformation directly from the object management in order to simulate the time behavior.
    SSD19.I.3 Input interface to SSD04 - Supporting Process Modeling It is possible to integrate process models generated with SSD04 without further transformation directly from the object management in order to simulate the time behavior.
    SSD19.I.4 Input interface to SSD11 - Supporting Database Specification It is possible to integrate logical schema specifications for databases and data structures generated with SSD11 without further transformation directly from the object management in order to simulate the time behavior.

    3.2 Requirements for the Methods Support

    SSD19.M.1 SIMU - Simulation Models
    SSD19.M.1.1 Resources
    SSD19.M.1.1.1 Restricted availability It is possible to restrict the availability of resources.
    Resources are CPU, bus, memory, controller, hard disks, peripherals; in a multitasking operating system, an individual program can only have parts of the total capacity at disposal.
    SSD19.M.1.1.2 Exclusive availability It is possible to make resources available exclusively to a single process.
    SSD19.M.1.1.3 Simultaneous utilization It is possible to make resources available to different processes for simultaneous use.
    SSD19.M.1.1.4 Utilization rules It is possible to regulate the utilization of resources by a special procedure.
    There are rules for the access to a computer bus.
    SSD19.M.1.1.5 Mapping Without restrictions, it is possible to map resources.
    SSD19.M.1.1.6 Availability limitations It is possible to model all availability limitations.
    SSD19.M.1.2 Waiting queues
    SSD19.M.1.2.1 Mapping It is possible to map waiting queues.
    SSD19.M.1.2.2 Limitations It is possible to limit the capacity of waiting queues.
    The instruction code storage of a computer can be limited.
    SSD19.M.1.2.3 Priority rules It is possible to specify priority rules for waiting queues.
    SSD19.M.1.2.4 Changing the priority It is possible that the priorities in a waiting queue will change during the time or because of external influences.
    SSD19.M.1.2.5 Status request It is possible to request the status of a waiting queue at any time.
    SSD19.M.1.3 Activities
    SSD19.M.1.3.1 Preset time It is possible to preset the time demand for an activity.
    SSD19.M.1.3.2 Calculation of preset time It is possible to calculate the time demand for an activity with arbitrary formulas.
    SSD19.M.1.3.3 Time demand depending on activities It is possible that the time demand of an activity depend on its characteristics.
    SSD19.M.1.3.4 External influences It is possible that the time demand of an activity is determined by external influences.
    SSD19.M.1.3.5 Stochastic distribution It is possible that the time demand to execute an activity is stochastically distributed.
    SSD19.M.1.3.6 Optional combinations It is possible to optionally combine the above listed influence factors for activities.
    SSD19.M.1.4 Logical operations
    SSD19.M.1.4.1 AND/OR It is possible to specify at least the logical operations "AND" and "OR".
    SSD19.M.1.4.2 Impact on resources It is possible that logical operations reduce the availability of resources.
    SSD19.M.1.4.3 Impact on processing sequence It is possible that logical operations determine the processing sequence.
    SSD19.M.1.5 Events
    SSD19.M.1.5.1 External interventions It is possible to simulate external interventions by means of events.
    External interventions are user input, hardware interrupts, software interrupts.
    SSD19.M.1.5.2 Changing the system state It is possible that events change system states.
    Global and also continuous variables may change.
    SSD19.M.1.5.3 Impact on availability of resources It is possible that events have an impact on the availability of resources.
    The failure of system parts can thus be simulated.
    SSD19.M.1.5.4 Initialization of processes It is possible that events initialize processes.
    SSD19.M.1.5.5 Initialization by a process It is possible that events are initialized by processes.
    A process may cause a switching operation.
    SSD19.M.1.5.6 Initialization by status changes It is possible that events are initialized by status changes.
    When crossing a threshold value of a continuous status item, an event might be initialized.
    SSD19.M.1.6 Status changes
    SSD19.M.1.6.1 Continuous It is possible that system states change continuously.
    SSD19.M.1.6.2 Linear equations It is possible to describe status changes by linear equations.
    SSD19.M.1.6.3 Differential equations It is possible to describe status changes by differential equations.
    SSD19.M.1.6.4 Supply with solution procedures Solution procedures for equations are made available.
    SSD19.M.1.6.5 Impact of events It is possible to influence system states by events.
    SSD19.M.1.6.6 Impact of global variables It is possible to influence system states by global variables.
    Loading factors of resources may have an impact on the system behavior.
    SSD19.M.1.6.7 Impact of local variables It is possible to influence system states by local variables.
    Local variables are attributes of processes.
    SSD19.M.1.6.8 Impact on activity duration It is possible that a duration of activities is influenced by system states.
    SSD19.M.1.6.9 Independent development It is possible that system states develop independently of the modeled interconnections.
    Thus it is possible to describe external influences with regard to measuring and control technology systems.
    SSD19.M.1.7 Interrupts
    SSD19.M.1.7.1 Interrupt at any time The simulation is interruptible at any time.
    SSD19.M.1.7.2 Manual It is possible to cause interrupts manually.
    SSD19.M.1.7.3 Predefined It is possible to predefine interrupts.
    SSD19.M.1.7.4 Time-oriented It is possible that interrupts are oriented on the simulation time.
    SSD19.M.1.7.5 Status-oriented It is possible that interrupts are oriented on system states.
    SSD19.M.1.7.6 Event-oriented It is possible that interrupts are linked with events.
    The simulation can be interrupted after a certain event has occurred.
    SSD19.M.1.7.7 Status representation During an interrupt, it is possible to represent all states.
    Variables can be queried.
    SSD19.M.1.7.8 Status changes It is possible to change system states manually.
    Variables or parameters can be changed.
    SSD19.M.1.7.9 Sequence changes It is possible to intervene in the simulation process.
    Processes can be interrupted or re-initialized.
    SSD19.M.1.7.10 Step-by-step continuation It is possible to continue the simulation on a step-by-step basis after an interruption.
    SSD19.M.1.7.11 Unlimited continuation Without restrictions it is possible to continue the simulation after an interruption.
    SSD19.M.1.8 Status backup
    SSD19.M.1.8.1 Storing It is possible to store simulation states.
    SSD19.M.1.8.2 Reloading It is possible to reload simulation states.
    SSD19.M.1.9 Logging It is possible to generate a sequence list containing all processes, activities and events happened.

    3.3 Requirements for Functions

    SSD19.F.1 Animation It is possible to visualize the simulation by an animation.

    3.4 Other Requirements

    SSD19.O.1 Macro language It is possible to control the simulation process by means of a macro language.
    SSD19.O.2 Upward compatibility It must be possible to process objects generated with an older release of the tool with the later release of that tool, without loss of information and functionality.
    SSD19.O.3 Procedural command language The tool has a procedural command language that can be applied by the user to generate and run macros or procedures.
    SSD19.O.4 Complexity There is no limitation of the complexity caused by the tool itself.

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