Simulation Kit

Through powerful and easy-to-use tools Simulation Kit serves the need for Numerical Analysis, Mechanical Engineering, Electrical Engineering, Thermodynamics, Chemical Engineering and Control Systems.

Simulation Kit was a collection of objects specifically developed for continuous system modeling and simulation on NEXTSTEP computers. Used in conjunction with the NEXTSTEP development environment, the Simulation Kit provided the ideal conditions for developing and analyzing object-oriented simulations.

The object-oriented nature of the Simulation Kit allowed simulation elements to be independently validated. In addition, structuring, sequencing, and execution of the simulation was performed by the core objects without direct user intervention. This meant that more time could be spent validating the simulation rather than debugging it.

What maked SimulationKit best:

1. The Simulation Kit was the only continuous simulation product available under NEXTSTEP.
2. The Simulation Kit provided a truly object-oriented modeling and simulation environment.
3. The Simulation Kit allowed sequential or parallel execution of processes as well as multiple clocks at different rates for advanced applications.
4. The Simulation Kit was flexible, reliable, reusable, and user-extensible.
5. The Simulation Kit included source code and documentation for nineteen example objects and simulations.

Both academic and professional users have found the Simulation Kit to be a powerful yet easy-to-use tool for modeling, analyzing, and teaching linear and non-linear continuous systems, numerical integration, and the numerical solution of differential equations. Typical application areas included: numerical analysis, mechanical engineering, electrical engineering, thermodynamics, chemical engineering, and control systems.

• Multiple clocks allow simulations to contain "fast" and "slow" subsystems.
• Process prioritization permits fine control over the execution of the simulation for techniques such as cascaded integration.
• Process class—generates output values based on its input and parameter values. Examples are gains, summers, and multipliers.
• Active Process class—generates output values in a similar manner to Process but maintains an internal state and uses one or more Clocks as a time base. Examples are integrators and sample-and-holds.
• Clock class—causes the evaluation of Active Processes at specified times. Examples are fixed-increment clocks and one-shot timers.
• Signal class—permits the output of a process to drive inputs of other processes.
• Composite class—allows several processes (connected by Signals) to be grouped together and treated as a single process in a higher context.
• Simulation class—manages the execution sequences of processes to allow the model to be simulated in the desired manner.
• Expression class—provides a mechanism for process parameters to be specified in terms of higher-context parameters.

Q: Was the Simulation Kit a NEXTSTEP app?
A: The Simulation Kit was not an application; it is acollection of nongraphical Objective-C objects, much in the same manner as the Indexing Kit from NeXT.

Q: Does the Simulation Kit include source code?
A: The Simulation Kit includes source code for nineteen example objects (e.g. summers, gains, and integrators) and simulations; source code is not provided for the seven abstract core classes which make up the foundation of the Kit.

Q: Does any documentation come with the Simulation Kit?
A: Each of the Simulation Kit objects (the fifteen example objects and the seven core objects) and the four example simulations are fully documented on-line and indexed for use with Digital Librarian. An introduction describes the mothodology for modeling and simulation systems using the Simulation Kit.

Q: Can the Simulation Kit be used to model discrete processes?
A: The Simulation Kit is currently unable to model and simulation discrete (i.e. event-driven) systems; only continuous systems can presently be modeled and simulated with the Simulation Kit.

Q: How are systems modeled and simulated using the Simulation Kit?
A: The Simulation Kit uses a block diagram abstraction to model continuous systems; thus, a simulation is constructed of process objects (such as summers, gains, and integrators) which are connected by signal objects. Clock objects are used to control the timing of the simulation (such as the integration step time), and the simulation object manages the execution of the processes in the proper order.

Q: How are new processes created using the Simulation Kit?
A: New processes may be created by directly coding the function in Objective-C as a subclass of the process object or by combining existing process objects into a composite process object.

Q: How do I obtain useful output from a simulation?
A: The output from a simulation is generated as the simulation executes, and may be output to a file, to an application in which the simulation is embedded, to an external application, or any other manner that the programmer desires. Examples are provided for importing and viewing the output graphically through Mathematica as well as several other packages.

Requires NEXTSTEP Release 3.1 or higher.
Shipped in Multi-Architecture Binary (MAB) format.

©1993 Alembic Systems International. Simulation Kit was a trademark of Doberman Systems.
SimulationKit was a registered trademark of Doberman Systems. All Rights Reserved.

Alembic Systems International