Generating Labour Cost Budget for a Construction-Oriented Fabrication Facility: Simulation-based Resource Scheduling Approach

2021 ◽  
Author(s):  
Leila Zahedi ◽  
Ming Lu
Keyword(s):  
Discrete Event ◽  
Highway Bridges ◽  
Labour Cost ◽  
Steel Girder ◽  
Event Simulation ◽  
Simulation Based ◽  
The Cost ◽  
The Impact ◽  
Productive Time

A novel labour-hour budgeting methodology is proposed by integrating productivity concepts in project scheduling and budgeting to enhance the accuracy of labour cost budgeting for planning labour-intensive projects. The proposed methodology applies discrete event simulation approach to represent crew formation, labour resource utilization and labour resource flowing between consecutive activities, which allows for quantitatively characterizing the impact of labour semi-productive time on labour cost budgeting as a time-dependent variable. Simulation-based assessment of variations in crew sizes and labour allocations is conducive to reducing semi-productive time and thus enhancing the cost performance of the whole project. The proposed methodology is then applied in a real-world case study for planning steel girder fabrication projects in construction of highway bridges. Not limited to budgeting for labour resources in construction-oriented fabrication facility, the research contributions are also significant to other construction planning settings where limited resources are shared and utilized among different activities.

Abstract 2524: Increasing the Proportion of Patients Treated with Stroke Thrombolysis: Reducing In-hospital Delays has Substantially More Impact than Extension of the Time Window

Stroke ◽  
2012 ◽  
Vol 43 (suppl_1) ◽  
Author(s):  
Martin A James ◽  
Thomas Monks ◽  
Ken Stein ◽  
Martin Pitt
Keyword(s):  
Time Window ◽  
Discrete Event ◽  
Fold Increase ◽  
Service Improvement ◽  
Disability Benefit ◽  
Prospective Data ◽  
Stroke Service ◽  
Event Simulation ◽  
Simulation Based ◽  
The Impact

Background Pooled analyses show the benefit of IV alteplase for ischemic stroke up to 4·5 hours after onset, and expert guidelines have been updated to reflect this. However, the benefit from thrombolysis is critically time-dependent, and the additional benefit from extending the time window may be jeopardised by in-hospital delays. Methods We developed a discrete-event simulation based on prospective data from 1142 acute stroke patients arriving at our large district hospital over a two-year period to April 2011, modelling the time spent in the ED for triage and assessment, brain imaging and, if applicable, thrombolysis. Outputs from the model included arrival to treatment times (ATT), percentage of strokes thrombolysed, and the number of thrombolysed patients with a 90 day modified Rankin Scale (mRS) of 0-1. We sought to model the current stroke pathway (treatment <3 hours of onset), and compare it with developmental scenarios exploring the impact of extending treatment from 3 to 4.5 hours, of ED staff alerting the stroke service at triage, of ambulance pre-alert to the stroke service, and combinations of these measures. Results The model illustrates that extending the treatment window modestly increases the percentage of acute strokes thrombolysed, from 5% to 6% (95% CI 5.8-6.1%), and increases the number of thrombolysed patients with mRS 0-1 by 7 per year (95% CI 5.9-8.0). Both the triage alert and ambulance pre-alert scenarios increase thrombolysis rates to 15% (95% CI 14.9% to 15.7%); but the ambulance pre-alert reduces ATT by a mean of 27 mins (95% CI 26.3-28.4) compared to the triage alert scenario. The ambulance pre-alert scenario increases the number of thrombolysed patients with mRS 0-1 by 35/year (95% CI 32.9-37.7) compared to 22 (95% CI 20.4-23.5) in the triage alert scenario. Combining the treatment extension with either alerting measure does not increase the thrombolysis rate further (15%, 95% CI 14.7-15.1%). Sensitivity analysis illustrates that the pre-alert system is the least vulnerable to a drop in compliance rates. Conclusions Our simulation model shows that the greatest disability benefit accrues from measures to substantially reduce in-hospital delays to alteplase treatment - a potential three-fold increase in the proportion of patients treated. Compared to extending the time window for alteplase from 3 to 4.5 hours, eradicating in-hospital delays to treatment offers a five-fold greater disability benefit, and this should be the pre-eminent focus of service improvement for all emergency receiving hospitals.

Analyzing the Return on Investment Associated With Prognostics and Health Management of Electronic Products

2008 ◽  
Author(s):  
Kiri Feldman ◽  
Peter Sandborn
Keyword(s):  
Health Management ◽  
Discrete Event ◽  
Prognostics And Health Management ◽  
Potential Cost ◽  
Product Usage ◽  
Cost Avoidance ◽  
Event Simulation ◽  
Business Cases ◽  
The Cost

Prognostics and Health Management (PHM) provides an opportunity for lowering sustainment costs, improving maintenance decision-making and providing product usage feedback into the product design and validation process. The adoption of PHM approaches requires consideration and planning for integration into new and existing systems, operations, and processes. However, PHM must provide a significant advantage in order to add value for the maintenance process and commitments to implement and support PHM approaches cannot be made without the development of supporting business cases. The realization of PHM requires implementation at different levels of scale and complexity. The maturity, robustness, and applicability of the underlying predictive algorithms impact the overall efficacy of PHM within an enterprise. The utility of PHM to inform decision-makers within tight scheduling constraints and under different operational profiles likewise affects the cost avoidance that can be realized. This paper presents a case study conducted using a stochastic discrete event simulation model to determine the benefits and potential cost avoidance offered by electronics PHM (e-PHM). The case study of a multifunctional display in a Boing 737 compared the life cycle costs of a system employing unscheduled maintenance approaches to the same system using a precursor to failure PHM approach.

A Simulation-Based Ergonomic and Operational Analysis for the Improvement of a Fish Processing Factory Ship

2013 ◽  
Vol 9 (3) ◽  
pp. 279-295
Author(s):  
Nadia Rego Monteil ◽  
Diego Crespo Pereira ◽  
David del Rio Vilas ◽  
Rosa Rios Prado
Keyword(s):  
Discrete Event ◽  
Process Efficiency ◽  
Fish Processing ◽  
Event Simulation ◽  
Organizational Effects ◽  
Simulation Based ◽  
Operational Improvement ◽  
Combined Simulation ◽  
Board Process

AbstractThis article presents a case study of general ergonomic and operational improvement of the on board process in factory ships. The process includes several lines with automatic and manual operations for processing caught fish as different products. It is a complex system with a great variety of operation possibilities. An exploratory simulation model of the plant and the human tasks is developed as a way to identify improvement opportunities. A combined simulation approach has been adopted for the characterization and improvement of the process comprising (i) a Discrete Event Simulation (DES) to develop the analysis of the production system and experiment with operational rules and (ii) a DHM-based study to analyse the present ergonomic conditions on the manual operations and to propose alternative workstation designs that could lead to effective and ergonomic improvement. As a result, we could characterize the process efficiency in different production scenarios, the organizational effects in the packing workstation and the ergonomic and operational assessment of the packing operations.

scholarly journals Optimizing two-dimensional renewable warranty policies for sensor embedded remanufactured products

2017 ◽  
Vol 10 (2) ◽  
pp. 145 ◽  
Author(s):  
Ammar Alqahtani ◽  
Surendra M. Gupta
Keyword(s):  
Preventive Maintenance ◽  
Discrete Event ◽  
Two Dimensional ◽  
Experimental Conditions ◽  
Specific Product ◽  
Event Simulation ◽  
Recovery System ◽  
The Cost ◽  
Warranty Policies ◽  
The Impact

Purpose: Remanufactured products, in addition to being environment friendly, are popular with consumers because they can offer the latest technology with lower prices in comparison to brand new products. However, some consumers are hesitant to buy remanufactured products because they are skeptical about the quality of the remanufactured product and thus are unsure of the extent to which the product will render services when compared to a new product. A strategy that remanufacturers may employ to entice customers is to offer warranties on remanufactured products. To that end, this paper studies and scrutinizes the impact of offering renewing warranties on remanufactured products. Specifically, the paper suggests a methodology which simultaneously minimizes the cost incurred by the remanufacturers and maximizes the confidence of the consumers towards buying remanufacturing products.Design/methodology/approach: This study uses discrete-event simulation to optimize the implementation of a two-dimensional renewing warranty policy for remanufactured products. The implementation is illustrated using a specific product recovery system called the Advanced Remanufacturing-To-Order (ARTO) system. The experiments used in the study were designed using Taguchi’s Orthogonal Arrays to represent the entire domain of the recovery system so as to observe the system behavior under various experimental conditions. In order to determine the optimum strategy offered by the remanufacturer, various warranty and preventive maintenance scenarios were analyzed using pairwise t-tests along with one-way analysis of variance (ANOVA) and Tukey pairwise comparisons tests for every scenario.Findings: The proposed methodology is able to simultaneously minimize the cost incurred by the remanufacturer, optimize the warranty price and period, and optimize the preventive maintenance strategy resulting in increased consumer confidence.Originality/value: This is the first study that evaluates in a quantitative and comprehensive manner the potential benefits of offering warranties with preventive maintenance on remanufactured products.

scholarly journals Quantifying the Impact of Inspection Processes on Production Lines through Stochastic Discrete-Event Simulation Modeling

Modelling ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 406-424
Author(s):  
Pablo Martinez ◽  
Rafiq Ahmad
Keyword(s):  
Discrete Event Simulation ◽  
Lean Manufacturing ◽  
Manufacturing Industry ◽  
Discrete Event ◽  
Production Lines ◽  
Event Simulation ◽  
Inspection Systems ◽  
The Cost ◽  
Multistage Production ◽  
The Impact

Inspection processes are becoming more and more popular beyond the manufacturing industry to ensure product quality. Implementing inspection systems in multistage production lines brings many benefits in productivity, quality, and customer satisfaction. However, quantifying the changes necessary to adapt the production to these systems is analytically complicated, and the tools available lack the flexibility to visualize all the inspection strategies available. This paper proposed a discrete-event simulation model that relies on probabilistic defect propagation to quantify the impact on productivity, quality, and material supply at the introduction of inspection processes in a multistage production line. The quantification follows lean manufacturing principles, providing from quite basic quantity and time elements to more comprehensive key performance indicators. The flexibility of discrete-event simulation allows for customized manufacturing and inspection topologies and variability in the tasks and inspection systems used. The model is validated in two common manufacturing scenarios, and the method to analyze the cost-effectiveness of implementing inspection processes is discussed.

Quantitative Analysis of the Impact of Inter-Line Conveyor Capacity for Throughput of Manufacturing Systems

2021 ◽  
Vol 11 (1) ◽  
pp. 1-17
Author(s):  
Priyanka Raosaheb Dhurpate ◽  
Herman Tang
Keyword(s):  
Quantitative Analysis ◽  
Manufacturing Systems ◽  
Discrete Event ◽  
New Approach ◽  
Event Simulation ◽  
System A ◽  
Automotive Assembly ◽  
Random Failure ◽  
The Impact

The objective of this study is to identify the impact of an inter-line conveyor on the throughput performance of manufacturing systems and determine the capacity of an inter-line conveyor to improvise productivity. First, manufacturing system for an automotive assembly line is modeled by adopting the methodology of two lines with an inter-line conveyor system. A quantitative analysis of an inter-line conveyor capacity is carried out under different conditions and capacities using discrete event simulation (DES). The initial results are obtained to justify the purpose of an inter-line conveyor followed by introducing a random failure of a station for the duration of 10 minutes, 30 minutes, and catastrophic breakdown of two hours at upstream and downstream line separately. The case study outcomes show that, 20 unit is an optimum capacity resulting in improved productivity. The findings of the different stoppage and catastrophic breakdown study show the buffering of an inter-line conveyor may serve as a new approach and guideline to the buffer stack design and scheduling maintenance.

scholarly journals Enhanced coverage by integrating site interdependencies in capacitated EMS location models

2021 ◽  
Author(s):  
Matthias Grot ◽  
Tristan Becker ◽  
Pia Mareike Steenweg ◽  
Brigitte Werners
Keyword(s):  
Discrete Event ◽  
Mathematical Formulation ◽  
Optimization Approach ◽  
Solution Quality ◽  
Similar System ◽  
Event Simulation ◽  
Simulation Based ◽  
Average System ◽  
Simplifying Assumptions ◽  
A Site

AbstractIn order to allocate limited resources in emergency medical services (EMS) networks, mathematical models are used to select sites and their capacities. Many existing standard models are based on simplifying assumptions, including site independency and a similar system-wide busyness of ambulances. In practice, when a site is busy, a call is forwarded to another site. Thus, the busyness of each site depends not only on the rate of calls in the surrounding area, but also on interactions with other facilities. If the demand varies across the urban area, assuming an average system-wide server busy fraction may lead to an overestimation of the actual coverage. We show that site interdependencies can be integrated into the well-known Maximum Expected Covering Location Problem (MEXCLP) by introducing an upper bound for the busyness of each site. We apply our new mathematical formulation to the case of a local EMS provider. To evaluate the solution quality, we use a discrete event simulation based on anonymized real-world call data. Results of our simulation-optimization approach indicate that the coverage can be improved in most cases by taking site interdependencies into account, leading to an improved ambulance allocation and a faster emergency care.

Sign in / Sign up

Export Citation Format

Share Document