journal article
LitStream Collection
Home
doi: 10.1177/003754979306000603pmid: N/A
In the simulation world view, there are three methods of constructing a simulation in common use: event scheduling, process orientation, and activity scanning (or three- phase approach). Because the three-phase approach has advantages of both modeling flexibility and modularity, we propose a simulation modeling tool, EPNSim, extended from the ordinary Petri Nets (PNs) to generate a language-independent pseudo code for the three-phase discrete simulation. Using the proposed method, the modeling processes of the three-phase discrete simulation can be concisely represented. In addition, it preserves the relative analytic properties of the original Petri net models (e.g. boundedness, liveliness, etc.), which are important for designing a system.
Harrington, Brian E.; Fishwick, Paul A.
doi: 10.1177/003754979306000604pmid: N/A
Modern Simulation Program Generators (SPGs) must address four key issues: portability, user interface, consistency and extensibility. Portable SPGs allow the user to edit the model outside of the SPG giving the user the flexibility to add features not supported by the SPG. An SPG's user interface should mimic the user's perception of the system to be modelled. Often the user visualizes the model as a network diagram. The user interface and the SPG's consistency deter mine ease-of-use. SPGs should be developed under a standard environment to provide consistency between programs. They should be modular, to allow the code generator to be modified as new simulation tools are developed. Xsimcode addresses each of these issues. It is a portable SPG, providing flexibitity for experienced modelers. It uses a graphical, direct manipulation interface to represent the simulation model. A noun-verb dialogue limits the user's choices once an object is selected. As an X-Windows program, Xsimcode's interface is consistent with many other X-Windows programs. Xsimcode's user interface module and code generation module are separated by a data structure, allowing Xsimcode to be extended to support other simulation languages or ported to other windowing environments.
doi: 10.1177/003754979306000605pmid: N/A
This research presents an improved lumped- parameter model that combines favorably its simplicity and precision to represent appropriately an automotive valve-gear system, by means of the inclusion of a fluidic pressure element within the modeling of the hydraulic lifter, and by considering the hysteretic behavior of the pushrod under cyclic loading. Realistic values have been chosen for the parameters of this cam-follower mechanical system, and the checking of this modified mathematical model has been accomplished by means of a qualitative comparison with other models previously conceived, and with previous experimental results obtained from an automobile engine. The digital computer simulation allows the determination of the cam speed for which the valve toss occurs, whose value is of fundamental importance in evaluating the design of automotive cam mechanisms.
Ozdemirel, Nur E.; Mackulak, Gerald T.
doi: 10.1177/003754979306000607pmid: N/A
Simulation experts know very well that there are similarities between the models they build for different manufacturing system. This article describes a module based generic model generator for discrete manufacturing systems. The module based generator was developed from a group technology (GT) classification scheme. The GT scheme uses common model features as a basis for creating generic model components. Specific user models are constructed by modifying and configuring the generic models rather than building them from scratch, thus reducing the effort and skill expected of the user in the process of model abstraction, construction, and validation/ verification.
Showing 1 to 8 of 8 Articles