Modelling the behaviour of engine assembly workers

Presents a prototype modelling methodology that provides a generic approach to the creation of quantitative models of the relationships between a working environment, the direct workers and their subsequent performance. Once created for an organisation, such models can provide a prediction of how the behaviour of their workers will alter in response to changes in their working environment. The goal of this work is to improve the decision processes used in the design of the working environment. Through improving such processes, companies will gain better performance from their direct workers, and so improve business competitiveness. This paper first presents the need to model the behaviour of direct workers in manufacturing environments. To begin to address this need, a simplistic modelling framework is developed, and then this is expanded to provide a detailed modelling methodology. There then follows a description of an industrial evaluation of this methodology at Ford Motor Company. This modelling methodology has been assessed in this case study and has been found to be valid in this case. There are many challenges that this theme of research needs to address. The work described in this paper has made an important first step in this area, having gone some way to establishing a generic methodology and illustrating its potential value. Our future work will build on this foundation

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

Optimisation of compressed air system’s energy usage through discrete event simulation: Compressor performance

Compressed air systems (CAS) utilised in manufacturing processes require significant energy input for operation. The estimated cost of producing compressed air is considered high with little transparency available when assessing its value in manufacturing. There is currently poor awareness of the performance of CAS in relation to its equipment utilisation and energy optimisation. This paper presents a modified approach to the Energy Blocks methodology for representation and simplification of compressed airflow profiles in discrete event simulations (DES). The presented AirBlocks methodology significantly reduces the aggregate data required to represent the dynamic and interdependent nature of CAS. Combining the AirBlocks approach with manufacturing throughout productivity simulations allows a productivity oriented compressed air demand profile to be developed. This offers the capacity to estimate periods of sustained peak, average and minimum air demand, incidents of production stoppages due to air demand, incidents of production due to air starvation and, identify waste and saving potential in the system. This paper includes an industrial case study where the AirBlocks approach was used in evaluating the performance of an existing CAS. Through simulation - poor compressor utilisation and regular incidents of air starvation were identified as symptoms of insufficient CAS volumetric capacity and an oversized compressor system in an automotive engine manufacturing plant

Knowledge-based improvement: simulation and artificial intelligence for identifying and improving human decision-making in an operations system

The performance of most operations systems is significantly affected by the interaction of human decision-makers. A methodology, based on the use of visual interactive simulation (VIS) and artificial intelligence (AI), is described that aims to identify and improve human decision-making in operations systems. The methodology, known as 'knowledge-based improvement' (KBI), elicits knowledge from a decision-maker via a VIS and then uses AI methods to represent decision-making. By linking the VIS and AI representation, it is possible to predict the performance of the operations system under different decision-making strategies and to search for improved strategies. The KBI methodology is applied to the decision-making surrounding unplanned maintenance operations at a Ford Motor Company engine assembly plant

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

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

Humans:the missing link in manufacturing simulation?

Computer based discrete event simulation (DES) is one of the most commonly used aids for the design of automotive manufacturing systems. However, DES tools represent machines in extensive detail, while only representing workers as simple resources. This presents a problem when modelling systems with a highly manual work content, such as an assembly line. This paper describes research at Cranfield University, in collaboration with the Ford Motor Company, founded on the assumption that human variation is the cause of a large percentage of the disparity between simulation predictions and real world performance. The research aims to improve the accuracy and reliability of simulation prediction by including models of human factors

Improving the design process for factories:modelling human performance variation

Theprocess of manufacturing system design frequently includes modeling, and usually, this means applying a technique such as discrete event simulation (DES). However, the computer tools currently available to apply this technique enable only a superficial representation of the people that operate within the systems. This is a serious limitation because the performance of people remains central to the competitiveness of many manufacturing enterprises. Therefore, this paper explores the use of probability density functions to represent the variation of worker activity times within DES models

A simple energy usage toolkit from manufacturing simulation data

A fundamental problem in energy management is the inability to clearly predict any possible energy saving opportunities. The cost of both under or overestimating potential returns on investment can be prohibitive to a decision maker. In recent years the simulation of energy usage using existing manufacturing simulation tools has increased in popularity among researchers, but it is energy managers who need to see the benefits of this discipline. This paper proposes an interactive manufacturing energy management tool which makes use of existing productivity simulation models for the prediction of energy usage. An interactive Microsoft® Excel® based tool is developed to control Lanner’s WITNESS® discrete-event simulation software using Microsoft® Visual Basic® for Applications. The tool has the ability to predict potential areas where energy saving opportunities can be made within a complex manufacturing line, and is accessible from management presentations and proposals. The interactivity of the tool provides an environment which facilitates efficient hypothesis testing. The paper includes an industrial case study where the approach was used to quantify theoretical savings from certain energy usage reduction scenarios within a complex automotive engine manufacturing line

Investigation Into ERP-Based Symbiotic Simulation Project Implentation On Ford Engine Production Line: Challenges, Opportunities and Prospects

The paradigm of Symbiotic Simulation describes a close relationship between a simulation system and the physical system. This relationship is usually mutually beneficial, wh ereby the simulation system benefits from a steady supply of real -time data from the physical system, while the physical system benefits from the optimised decisions arrived at through what -if experiments executed by the simulation system. In furtherance o f existing work towards developing symbiotic simulation systems anchored on integration with corporate information systems, this paper presents research into an industrial application of symbiotic simulation to improve the simulation project life -cycles at a major automotive engine production line controlled by a shop floor information system. We discuss inexorable issues associated with the implementation of the relatively novel concept of symbiotic simulation, highlight the challenges to successful implementation in a corporate change -averse culture, suggest solutions for surmounting them and discuss the impact and prospects for symbiotic simulation with ERP integration