Time management issues in COTS distributed simulation: A case study

Commercial off-the-shelf (COTS) simulation packages are widely used in industry. Several international groups are currently investigating techniques to integrate distributed simulation facilities in these packages. Through the use of a case study developed with the Ford Motor Company, this paper investigates time management issues in COTS simulation packages. Time management is classified on the basis of the ordering of events that are externally produced to a federate and the ordering of these with events that occur within a COTS simulation package federate. Several approaches to the latter are discussed and one approach is presented as the most effective. Finally the paper presents a bounded buffer problem and proposes the classification of information sharing with respect to the certification of solution

Simulation modeling of tool delivery system in a machining line

This paper describes an industrial project aiming to enhance the existing simulation modeling suites used at a car engine factory in the UK. The company continues to enhance its simulation modeling capabilities towards so called the `total plant modeling' which not only covers the production facilities but also key ancillary facilities. Tool delivery is one such ancillary process. The existing modeling practices at the company are limited to modeling tool changes and assume that tools meet their expected life and the replacement is always available. In reality, the tools are not always reaching the expected life, the facilities in the tool crib are a limiting resource and the tool inventory has to be minimized. The tool delivery system developed in this project has specific features that model how the tool crib operates, how tools are supplied to the machining lines and various operating strategie

Investigating distributed simulation at the Ford motor company

Engine production is a complex process that requires the manufacturing and assembly of a wide variety of components to create a varied product mix. Simulation plays a key role in the planning process of a new production line to determine if it can meet expected demand. However, these simulations can be very time consuming and can often take up to a day to execute a single run. This paper investigates how distributed simulation based on the IEEE 1516 High Level Architecture and the emerging standard COTS Simulation Package Interoperability Product Development Group (CSPI-PDG) Type I Interoperability Reference Model could be used to reduce the time taken for a single simulation run. CSP interoperability and the problem of integrating CSPs with HLA software (the runtime infrastructure) are presented. New prototype benchmarking software, the COTS Simulation Package Emulator (CSPE), which is being developed to investigate distributed simulation problems, is discussed. The paper then develops a case study of how this was used to investigate the feasibility of using distributed simulation at Ford. The paper discusses results obtained from this case study and suggests that distributed simulation could indeed be beneficial to Ford

Grid-enabling FIRST: Speeding up simulation applications using WinGrid

The vision of grid computing is to make computational power, storage capacity, data and applications available to users as readily as electricity and other utilities. Grid infrastructures and applications have traditionally been geared towards dedicated, centralized, high performance clusters running on UNIX flavour operating systems (commonly referred to as cluster-based grid computing). This can be contrasted with desktop-based grid computing which refers to the aggregation of non-dedicated, de-centralized, commodity PCs connected through a network and running (mostly) the Microsoft Windowstrade operating system. Large scale adoption of such Windowstrade-based grid infrastructure may be facilitated via grid-enabling existing Windows applications. This paper presents the WinGridtrade approach to grid enabling existing Windowstrade based commercial-off-the-shelf (COTS) simulation packages (CSPs). Through the use of a case study developed in conjunction with Ford Motor Company, the paper demonstrates how experimentation with the CSP Witnesstrade and FIRST can achieve a linear speedup when WinGridtrade is used to harness idle PC computing resources. This, combined with the lessons learned from the case study, has encouraged us to develop the Web service extensions to WinGridtrade. It is hoped that this would facilitate wider acceptance of WinGridtrade among enterprises having stringent security policies in place

Using empirical evidence of variations in worker performance to extend the capabilities of discrete event simulations in manufacturing

Discrete event simulation of manufacturing systems has become widely accepted as an important tool to aid the design of such systems. Often, however, it is applied by practitioners in a manner which largely ignores an important element of industry; namely, the workforce. Workers are usually represented as simple resources, often with deterministic performance values. This approach ignores the potentially large effect that human performance variation can have on a system. A long-term data collection exercise is described with the aim of quantifying the performance variation of workers in a typical automotive assembly plant. The data are presented in a histogram form which is immediately usable in simulations to improve the accuracy of design assessment. The results show levels of skewness and range which are far larger than anticipated by current researchers and practitioners in the field

Simulation study for investment decisions on the EcoBoost camshaft machining line

Design/redesign of manufacturing systems is a complex, risky, and expensive task. Ford Motor Company’s Valencia Engine Plant faces this challenge as it plans to upgrade its machining and assembly lines to introduce the new EcoBoost engines. The research project described in this paper aimed to support the transition process particularly at the camshaft machining line by using simulation modelling techniques. A series of experiments was carried out using the simulation model developed, and recommendations were proposed based on the results of these experiments to support the decision as to where to invest on the line. The outcomes from the research project indicated that investment is required in terms of increasing the capacity of two bottleneck operations through retooling and improving the conveyor routing logic in one key area. Keywords: simulation modelling, closed-loop network, automotive production system

The SISO CSPI PDG standard for commercial off-the-shelf simulation package interoperability reference models

For many years discrete-event simulation has been used to analyze production and logistics problems in manufactur-ing and defense. Commercial-off-the-shelf Simulation Packages (CSPs), visual interactive modelling environ-ments such as Arena, Anylogic, Flexsim, Simul8, Witness, etc., support the development, experimentation and visua-lization of simulation models. There have been various attempts to create distributed simulations with these CSPs and their tools, some with the High Level Architecture (HLA). These are complex and it is quite difficult to assess how a set of models/CSP are actually interoperating. As the first in a series of standards aimed at standardizing how the HLA is used to support CSP distributed simula-tions, the Simulation Interoperability Standards Organiza-tion’s (SISO) CSP Interoperability Product Development Group (CSPI PDG) has developed and standardized a set of Interoperability Reference Models (IRM) that are in-tended to clearly identify the interoperability capabilities of CSP distributed simulations

An Investigation into the Use of Net-Conferencing Groupware in Simulation Modelling

Simulation modellers are major users of software tools. Advances in computing such as collaborative working tools and distributed technologies have created new possibilities for innovation in simulation modelling. Collectively, we address these as Collaborative Support for Simulation Modelling (CSSM). To contribute to CSSM, we consider the problem of whether or not it is possible to support human-to-human collaboration in simulation modelling through the use of commonly available groupware technology. The paper reviews aspects of human-to-human collaboration in the simulation modelling process and introduces an example of commonly available groupware technology, the net-conferencing groupware tool NetMeeting^R. Results of a survey into the perceived use of NetMeeting^R in simulation and some resulting applications of the net-conferencing tool that have emerged are presented

Using a simulation model for knowledge elicitation and knowledge management

The work reported in this paper is part of a project simulating maintenance operations in an automotive engine production facility. The decisions made by the people in charge of these operations form a crucial element of this simulation. Eliciting this knowledge is problematic. One approach is to use the simulation model as part of the knowledge elicitation process. This paper reports on the experience so far with using a simulation model to support knowledge management in this way. Issues are discussed regarding the data available, the use of the model, and the elicitation process itself. © 2004 Elsevier B.V. All rights reserved