Business & Service

This report presents an integrated simulation-based approach to study the on-site production of concrete frameworks by considering the multiple effects of weather on work task productivity and concrete curing process. The ExtendSim model created reports simulated construction time, cost, and CO₂ emissions for a specific construction setup to facilitate planning and decisions related to resource allocation strategies, construction schedules, different concrete types (including climate-improved concrete), and curing measures for different types of expected weather conditions.

This paper validates effects of online self-assessment tests as a formative assessment strategy for first year undergraduate courses. Achieved students' results such as test scores and pass rates are compared for three different generations for the same course while also being ranked against exam results of other courses taught in the same semester. The analysis points out that there is a statistically significant difference between the groups for half-semester tests and exam pass rates after online self-assessment tests were introduced. Positive effects on students' success are approximated for the overall institution using a simulation model. Results point out that a small increase in pass rates could significantly impact the overall success i.e. decrease of dropout rates.

Using ExtendSim, the author developed a model which allows extrapolation of the impact on key performance indicators (i.e. drop-out rate and study completion time) for the whole institution enabling analysis of potential opportunities. Simulated results were compared with the actual data from the information system to verify the correctness of the model.

In this paper, the effect that routing rules have on agent learning is researched. A nonlinear optimization framework for two kinds of expertise objectives are developed: one that seeks equal distribution of experience across the workforce (effectively cross-training) and one that aims to develop specialized expertise by prioritizing the routing of specific customer inquiries to specific agents. Analytical models of call center operations are inadequate to handle this task, so instead we turn to discrete-event simulation, and evaluate the effect of routing policies on agent expertise with a custom simulator developed in the ExtendSim modeling environment. Simulation results describe an efficient frontier in routing policies that depends on the underlying expertise objective function.

A Parisian high-rise office building used ExtendSim to simulate the flow of workers utilizing the building's elevators to determine if the elevator distribution was efficient.

In the mid 90s, the Deloitte & Touche Consulting Group built a Management Flight Simulator in ExtendSim to experiment with different management strategies for internal training sessions. The model focuses on the relationship between the economic factors of staffing levels, sales effort, competition, employee training, and market research. Control panels were set up within the model for trainees to vary input parameters in business factors such as staffing levels. Using this interface, class participants were able to use a sophisticated model with minimal knowledge of simulation.

Packages that accurately emulate the hybrid processes that characterize food and beverage manufacturing are making simulation more than just a snazzy presentation tool for upper management. Virtual Engineering's New Frontier describes users roughing out their production and packaging lines on screen to gain insight into the dynamics of their lines and where and why bottlenecks occur.

Pilot experience in the adoption of performance simulation approach to design, redesign, and acquisition of bottling lines for the Zarate plant of Cervecería y Maltería Quilmes S.A. This paper discusses the management of the huge bottling resources of the company: more than 36 lines in 12 factories, in 6 countries, with an aggregated investment value of $ 200 million, occupying more than a thousand people and producing 250 million cases a year of 300 different SKUs.

Any activity that receives inputs and convert them to outputs can be considered a process. So, essentially, similar equations are used in the theory of chemical, biochemical, nuclear, mechanical, and other types of process engineering modeling. This particular research group set out identify the processes, network of processes, process variables and process equations in food logistics. This paper introduces how process building, simulation run, and optimization can be carried out in a Food Distribution Centre with a message-based discrete event simulation software - ExtendSim. Simulation usage as a decision supporting tool in the hand of company management is introduced as well as the affect of wrong decisions on the extent of air pollution coming out from cooling vehicle.

Simulation modeling is a valuable complement to, rather than a replacement for, the traditional lean manufacturing analysis tools. For example, value stream mapping is a key tool; it is a good beginning. But it is static and typically only done for high-volume products or classes of products. Simulation allows the value stream map to become dynamic, and to model the range of probable val- ues—not just averages. It also allows linkages to other tools such as projected capacity utilization in a consistent manner.

Many service providers offer customers the choice of either waiting in a line, or going offine and returning at a dynamically determined future time. The best known example is the FASTPASS® system at Disneyland. To operate such a system, the service provider must first make an upfront decision on how to allocate service capacity between the two lines. Then, during system operation, he must dynamically provide estimates of the waiting times at both lines to each arriving customer. The estimation of offine waiting times is complicated by the fact that some offine customers do not return for service at their appointed time.

The paper Managing Service Systems with an Offine Waiting Option and Customer Abandonment shows that when demand is large and service is fast, for any fixed capacity allocation decision, the two-dimensional process tracking the number of customers waiting inline and offine collapses to one dimension, and characterize the one-dimensional limit process as a reflected diffusion with linear drift.

The analytic tractability of this one-dimensional limit process allows to solve for the capacity allocation that minimizes average cost, when there are costs associated with customer abandonments and queueing. It is further shown that in this limit regime, a simple scheme based on Little's law to dynamically estimate inline and offline wait times is effective.

Note: This paper was made possible with the help of an ExtendSim Research Grant for the final project of Vasiliki Kostami in obtaining his PhD in Operations Management from the University of Southern California.