Discrete Event Simulation

Abstract: We develop a simulation tool to support policy-decisions about healthcare for chronic diseases in defined populations. Incident disease-cases are generated in-silico from an age-sex characterised general population using standard epidemiological approaches. A novel disease-treatment model then simulates continuous life courses for each patient using discrete event simulation. Ideally, the discrete event simulation model would be inferred from complete longitudinal healthcare data via a likelihood or Bayesian approach. Such data is ...

Recently there has been a great deal of interest in performance evalution of parallel simulation. Most work is devoted to the time complexity and assumes that the amount of memory available for parallel simulation is unlimited. This paper studies the space complexity of parallel simulation. Our goal is to design an efficient memory management protocol which guarantees that the memory consumption of parallel simulation is of the same order as sequential simulation. (Such an algorithm is referred to as a optimal .) First, we derive the relationships among the space complexities of sequential simulation, Chandy-Misra simulation [2], and Time Warp simulation [7]. We show that Chandy-Misra may consume more storage than sequential simulation, or vice versa. Then we show that Time Warp never consumes less memory than sequential simulation. Then we describe cancelback , an optimal Time Warp memory management protocol proposed by Jefferson. Although cancelback is considered to be complete so...

Agility, speed and flexibility in production networks are required in today's global competition in the flat world. The accuracy of order date delivery promises is a key element in customer satisfaction. Agile production needs a management and evaluation tool for production changes. Discrete event simulation, DES, has mainly been used as a production system analysis tool, to evaluate new production system concepts, layout and control logic. DES can be used for operational planning as well, as shown in the paper. The simulation analysis gives a forecast of the future with given input values, thus production managers have time to react to potential problems and evaluate alternatives. A balance between multiple parallel customer orders and finite resources can be found. The authors are developing a system design evaluation method and also a decision support system for production managers. Two case studies with different approaches are described in the paper.

A freight terminal is a key node in a transportation network and the transit time of containers through this terminal represents one of the most relevant bottlenecks in logistic chains. The system performance reduction and the corresponding increase of transit time are often due to the increase of the freight flow without a corresponding increase of stacking and handling capacity. For this purpose it was decided to approach the problem by a discrete event simulation model, in order to reproduce the activities carried out inside an intermodal terminal, to calculate the total transit time and to identify the bottlenecks. The transit time of a cargo unit in a terminal is the summation of times required for the development of each phase of the process (waiting time + operational time). Therefore, the first step was the identification of the main activities and the analysis of waiting and operational phases, in order to quantify the times of each phase. For modelling the software Planima...

This paper describes efforts directed at the simulation and control of autonomous vehicles and pedestrians for use in driving simulators scenarios. It describes the use of artificial intelligence interactive systems, and the concepts of short time orders and long time goals to create the virtual traffic environment.

Discrete-event simulation (DES) and lean are approaches that have a similar motivation: improvement of processes and service delivery. Both are being used to help improve the delivery of healthcare, but rarely are they used together. This paper explores from a theoretical and an empirical perspective the potential complementary roles of DES and lean in healthcare. The aim is to increase the impact of both approaches in the improvement of healthcare systems. Out of this exploration, the ‘SimLean’ approach is developed in which three roles for DES with lean are identified: education, facilitation and evaluation. These roles are demonstrated through three examples of DES in action with lean. The work demonstrates how the fusion of DES with lean can improve both stakeholder engagement with DES and the impact of lean.► We identify theoretically and empirically the complementary roles of simulation and lean. ► The ‘SimLean’ framework provides three roles for simulation with lean in healthcare. ► We demonstrate the roles of simulation with lean through three example applications. ► The fusion of simulation with lean improves stakeholder engagement with simulation. ► The fusion of simulation with lean improves the impact of lean.

Semiconductor fabrication facilities (fabs) continue to expand in both complexity and volume. As a result, integrated models are required to determine even high level impacts to key success indicators. In order to gain insight into how the components of a factory impact performance metrics, Intel uses an integrated discrete-event simulation modeling approach. Two models, one fab capacity and one automation model, are used. This paper discusses the methodology for building and integrating both models, and the results from using this method.Both the fab capacity and automation models have a variety of input parameters that are required to drive the simulation. In addition, each model produces output parameters, some of which are used as inputs to the other model. An iterative feedback technique eventually results in a convergence on the appropriate data to feed the fab capacity model, which enables Intel to determine the impact of automation on 300mm wafer semiconductor manufacturing,...