4.35 Method Catgory "Simulation Models" (SIMU)


		4.35 Method Catgory "Simulation Models" (SIMU)

4.35 Methodenkategorie "Simulationsmodelle" (SIMU)

Contents
1 Identification/Definition of the Method
2 Brief Characteristic of the Method
3 Limits of the Methods Application
4 Specification of the Methods Allocation
5 Interfaces
6 Further Literature
7 Functional Tool Requirements

Contents		1 Identification/Definition of the Method 2 Brief Characteristic of the Method 3 Limits of the Methods Application 4 Specification of the Methods Allocation 5 Interfaces 6 Further Literature 7 Functional Tool Requirements

1 Identification/Definition of the Method

"Simulation Models" (SIMU) is a category of methods; the individual applicable simulation methods are described in more detail in SIMU - Simulation Models (in Annex 1) by listing the selection criteria. A special method is only defined within the scope of the operationalization. /Mattern, 1989/ can be used as an overview description.

2 Brief Characteristic of the Method

Objective and Purpose

The object of the simulation is to evaluate the feasibility of requirements by pointing out the effects on performance parameters and system behavior under dynamic aspects.

The dynamic effects are generated or estimated by integrating an operational scenario or a series of events into the model. The application of the simulation method is particularly useful when evaluating the following features:

meeting the quality requirements

response behavior for special input data

CPU utilization

memory utilization/capacity of storage

meeting the time limits on operation/application

man/machine interaction and response behavior

Operational Sequence

The principle of the simulation is that the system to be realized is analytically represented as a model while functions or respectively processes and main algorithms form the frame for the model. Apart from that, the scenario and the scenario data have to be developed. Feeding the simulation model with operational data will then result in the simulated performance profiles, e. g. as a time-dependent function. Different simulation runs with scenario versions and design alternatives result in the information about the performance behavior of the system. The results must be analyzed and evaluated, not only for the decision making but also for the design determining and the quality assurance.

Simulation models have to be developed according to the requirements, provided the suitable models are available.

In case a simulation model is developed, the following steps must usually be taken:

analysis of the simulation requirements
generation and specification of the simulation concept
assessment of the simulation concept
generation of test scenarios
development of the simulation model
testing the simulation model
making available the scenario test data and performing the simulation runs
analysis and evaluation of the simulation results
testing the simulation model
possible upgrade or modification of the simulation model

3 Limits of the Methods Application

Within the scope of the development method SIMU will be applied in the case where the reliability requirements are high and the environmental conditions are complex in a way that static investigations of feasibility and of resource demands are not sufficient.

Within the scope of QA method SIMU will be applied if the test cannot completely handle the performance and error proof since-among other things-special limitations, assumptions, and environmental conditions have to be taken into consideration.

4 Specification of the Methods Allocation

No.	Activity	Description
4.1	SD2.3 - Investigation of Feasibility	SIMU essentially covers dynamical aspects of feasibility checks. Therefore it is not possible to refer to a complete coverage of the subproduct System Architecture.Feasibility Studies.
4.2	SD5.2 - Analysis of Resources and Time Requirements	Method SIMU is applied for the specification of the time and resource demands on SW level. The simulations to be realized are based on the specified functional and communication structures of the corresponding SW Unit. By means of applying the methods it is only possible to specify the two mentioned characteristics. Therefore it is not possible to refer to a complete coverage of the subproducts SW Design (Module).Characteristic Quantities and SW Design (Database).Characteristic Quantities.
4.3	QA4.2 - Assessment of the Content of the Product	Method SIMU is applied to assess the following objects: User Requirements Technical Requirements SW Module SW Component Database SW Unit Segment System The assessment predominantly refers to dynamic characteristics and to the execution of functions under marginal conditions and full capacity use. Method SIMU only completely covers the assessment of the User Requirements and of the Technical Requirements only when used in combination with the methods REV - Review, STAT - Static Analysis, and T - Test. For the products SW module, SW Component, Database, SW Unit, Segment and System the assessment is only completely covered in combination with method T.