Precast concrete (PC) can potentially improve construction industry projects when used as a primary process in the precast concrete supply chain (PCSC). Successful inventory reduction and on-time delivery are essential in the PCSC because of critical scheduling and cost factors. To solve these challenges, this study applied Just-In-Time (JIT) strategies in the PCSC using the Discrete-Event Simulation (DES) model to help manufacturers identify the optimal decision. The factors considered were offsite inventory levels (based on days buffered) and batch delivery decisions that reduced supply penalties and improved construction performance. The model was validated based on a precast project experiment in Vietnam; the model provided a saving of 52% in manufacturer penalties and reduced construction idle work by 77%. An optimal combined decision was provided for the manufacturer, such as a 1day-4batch decision with maximum benefit and a 2day-2batch decision for safety using an uncertainty risk consideration in the PC wall panel study case. This research contributes a tool to help manufacturers in decision making and promotes the use of JIT applications/strategies in the PCSC process.

Concepts for aggregate modeling and simulation are presented and applied for the setting of the parameters of a CONWIP flow control system within the steel products cell at Grand Rapids Chair, a high-mix, low-volume manufacturing environment. Aggregation was accomplished by combining the over 100 types of products into one. This resulted in a single arrival process, routing modeled as random movement through workstations, and a single operation time distribution for each production operation. Aggregation reduced the effort required for model development, data analysis, validation, and simulation. The CONWIP control was shown to be effective in managing the work-in-process. A CONWIP parameter of 50 resulted in an equivalent throughput to that achieved with no limit on work-in-process. Lead time can be reduced by approximately 20% by increasing the CONWIP parameter to 58.

Emergency department (ED) overcrowding is a common issue in emergency medicine of Canada. Previous studies indicate that adding a physician in triage (PIT) can increase accuracy and efficiency in the initial process of patient evaluations. However, the PIT concept should be thoroughly researched before its widespread implementation can be recommended. This paper introduces the evaluation of impact of PIT on ED patient wait times and length of stay (LOS) using simulation modeling. A discrete-event simulation model of ED is built to simulate and predict the effect of PIT intervention. The model performance is validated using current-state ED flow metrics to quantitatively test multiple alternatives for ED improvements. Results show that the PIT implementation can reduce the ED patient LOS by an average of 34% and Waiting to be Seen time by 49% across all scenarios studied. The proposed method can be applied to improve the operation efficiency of healthcare systems in the current pandemic, COVID -19.