Thomas K. Keyser

Intelligent simulation: Integration of SIMIO and MATLAB to deploy decision support systems to simulation environment

Abstract Discrete-event simulation is a decision support tool which enables practitioners to model and analyze their own system behavior. Although simulation packages are capable of mimicking most tasks in a real-world system, there are some decision-making activities, which are beyond the reach of simulation packages. The Application Programmers Interface (API) of SIMIO provides a wide range of opportunities for researchers to develop their own logic and apply it during the simulation run. This paper illustrates how to deploy MATLAB, as a computational tool coupled with SIMIO, as a simulation package by using a new user-defined step instance named “CallMATLAB”. A manufacturing system case study is introduced where the CallMATLAB step instance is used to create an Iterative Optimization-based Simulation (IOS) model. This model is created to evaluate the performance of different optimizers. The benefits of this hybridization for other industries, including healthcare systems, supply chain management systems, and project management problems are discussed.

Tradeoffs between objective measures and execution speed in iterative optimization-based simulation (IOS)

In this paper an Iterative Optimization-based Simulation (IOS) framework is designed, developed and examined. This framework includes a threefold contribution of Simulation, Optimization and Database Manager. In this IOS model, optimization takes place repeatedly at the models operational level to optimize the combination of systems state variables during the simulation run. Predefined trigger events momentarily pause the simulation and activate optimization in order to optimize the systems configuration. This cycle replicates until the simulation reaches its timespan. By deploying this promising IOS model, practitioners can take advantage of a long-term simulation run of their system, while it optimizing several times according to the occurrence of predefined incidents. The main concern here is the trade-off between simulation and optimization which is examined in this study. The results prove a positive impact of the IOS approach on the systems performance measures, although it takes longer to execute compared to the Non-IOS approaches.

A novel Iterative Optimization-based Simulation (IOS) framework: An effective tool to optimize system’s performance

Abstract In this paper, a unique Iterative Optimization-based Simulation (IOS) framework is presented, which includes a threefold integration of simulation, optimization and database managers. With this IOS model, optimization occurs frequently at the operational level in order to optimize system variables during the simulation run. In other words, a trigger event momentarily pauses the simulation and signals the optimization manager to optimize the status of the system. Meanwhile, a snapshot of the system, which includes the system status parameters, is transferred to a database. The optimization manager uses this data as an input to the analytical modeling and solves the problem optimally by considering the pre-defined objectives, constraints and updated state of the system. The framework automatically re-formulates the mathematical model using updated parameters, and then, the optimization manager finds a solution in a reasonable amount of time. The database manager is then updated based on the current optimal solution and simulation continues from this point in time. This cycle is repeated for each trigger event in the system and lasts until simulation reaches its timespan. Deploying this promising IOS model enables practitioners to take advantage of long-term simulation runs of their system, while it has been optimized multiple times according to the occurrence of any predefined incidents. The performance of the proposed IOS framework is evaluated using a manufacturing case study, and its results are compared with Simulation-Based Optimization (SBO).

Iterative optimization-based simulation (IOS) with deterministic and stochastic trigger events in simulated time

A novel simulation-optimization model called Trigger-based Iterative Optimization-based Simulation (TIOS) framework is designed, developed and examined. This framework includes a threefold contribution of simulation, optimization and database manager. These system managers operate in harmony to achieve the goal of selecting the best system configurations (e.g. scheduling, resource allocation, etc.) for different states of the system. Considering the major activates that cause changes systems status, this frameworks is designed in such a way that updates the system configuration whenever needed. The proposed IOS approach is used to simulate a two-stage non-deterministic flow shop problem. The results prove a positive impact of the TIOS approach on the systems performance measures, although it takes longer to execute compared to the heuristic dispatching rules approaches.

A multidisciplinary design experience that addresses several ABET outcomes also provides a framework for international student collaboration

The faculty at Western New England College in the industrial engineering and biomedical engineering departments have developed a multidisciplinary laboratory design experience that integrates several ABET outcomes and serves to prepare students for the capstone senior design project. The ABET Outcomes addressed include c, d, e, f, g, and h, however others could be incorporated depending on the project. In addition, this experience serves to reinforce design concepts learned in previous courses and requires the students to develop real-world prototypes for implementation. The specific projects focus on designing and developing assistive technologies for disabled individuals employed at not-for-profit agencies. The devices provide the individuals with increased accessibility to employment opportunities. The students employ a variety of design tools including Manhattan, a web-based forum for sharing designs and communication. Recent projects in the area of manual work have included box folding, screw packaging, tape cutting, and folder assembly. The projects are successful in several ways. The students gain valuable interdisciplinary design experience, the not-for-profit agency gains needed assistance in their production, and the individuals with disabilities become more productive employees. This design experience provides a framework for emulating a modern product development environment with participating team members located at different universities around the world.