scholarly journals An Application of Discrete-Event Simulation in Estimating Emissions from Equipment Operations in Flexible Pavement Construction Projects

2017 ◽  
Vol 21 (7) ◽  
pp. 197-211 ◽  
Author(s):  
Charinee Limsawasd ◽  
Nathee Athigakunagorn
Keyword(s):  
Discrete Event Simulation ◽  
Construction Projects ◽  
Discrete Event ◽  
Flexible Pavement ◽  
Event Simulation ◽  
Pavement Construction

scholarly journals SAT modulo discrete event simulation applied to railway design capacity analysis

2021 ◽  
Author(s):  
Bjørnar Luteberget ◽  
Koen Claessen ◽  
Christian Johansen ◽  
Martin Steffen
Keyword(s):  
Discrete Event Simulation ◽  
Construction Projects ◽  
Software Verification ◽  
Ad Hoc ◽  
Discrete Event ◽  
Capacity Analysis ◽  
Railway Network ◽  
Event Simulation ◽  
Design Engineers ◽  
Railway Capacity

AbstractThis paper proposes a new method of combining SAT with discrete event simulation. This new integration proved useful for designing a solver for capacity analysis in early phase railway construction design. Railway capacity is complex to define and analyze, and existing tools and methods used in practice require comprehensive models of the railway network and its timetables. Design engineers working within the limited scope of construction projects report that only ad-hoc, experience-based methods of capacity analysis are available to them. Designs often have subtle capacity pitfalls which are discovered too late, only when network-wide timetables are made—there is a mismatch between the scope of construction projects and the scope of capacity analysis, as currently practiced. We suggest a language for capacity specifications suited for construction projects, expressing properties such as running time, train frequency, overtaking and crossing. Such specifications can be used as contracts in the interface between construction projects and network-wide capacity analysis. We show how these properties can be verified fully automatically by building a special-purpose solver which splits the problem into two: an abstracted SAT-based dispatch planning, and a continuous-domain dynamics with timing constraints evaluated using discrete event simulation. The two components communicate in a CEGAR loop (counterexample-guided abstraction refinement). This architecture is beneficial because it clearly distinguishes the combinatorial choices on the one hand from continuous calculations on the other, so that the simulation can be extended by relevant details as needed. We describe how loops in the infrastructure can be handled to eliminate repeating dispatch plans, and use case studies based on data from existing infrastructure and ongoing construction projects to show that our method is fast enough at relevant scales to provide agile verification in a design setting. Similar SAT modulo discrete event simulation combinations could also be useful elsewhere where one or both of these methods are already applicable such as in bioinformatics or hardware/software verification.

Improving materials logistics plan in road construction projects using discrete event simulation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Amin Alvanchi ◽  
Farshid Baniassadi ◽  
Mahdi Shahsavari ◽  
Hamed Kashani
Keyword(s):  
Discrete Event Simulation ◽  
Construction Projects ◽  
Construction Material ◽  
Discrete Event ◽  
Road Construction ◽  
Combinatorial Problem ◽  
The Body ◽  
Content Type ◽  
Event Simulation ◽  
Material Sources

PurposeMotivated by the high cost of material movements in road construction projects, past studies have used analytical methods to optimize materials logistics plans. A key shortcoming of these methods is their inability to capture the uncertain, dynamic and complex characteristics of the road construction material logistics. Failure to incorporate these characteristics can lead to sub-optimal results. The purpose of this study is to propose the use of discrete event simulation (DES) to address the existing shortfall.Design/methodology/approachDespite the powerful capabilities of DES models in capturing the operational complexities of construction projects, they have not been previously utilized to optimize the material logistics of road construction projects. The proposed DES-based method in this research captures the operational details of material logistics and uses a heuristic approach to overcome the combinatorial problem of numerous choices. The method was applied to a 63.5 km real-world road construction project case to demonstrate its capabilities.FindingsSix different material types from 28 material sources were used in the case. Approximately 1.5% of the material logistics costs were saved by following the proposed method and choosing appropriate material sources.Originality/valueThis research contributes to the body of knowledge by leveraging the capabilities of DES and presenting a novel method for improving the materials logistics plan of road construction projects. The proposed method provides practitioners with the basis for capturing the key operational details that were overlooked in the past. The proposed method can be adopted in road construction projects to reduce the overall material procurement cost.

scholarly journals Economic Evaluation of Bariatric Surgery in Mexico Using Discrete Event Simulation

2012 ◽  
Vol 1 (2) ◽  
pp. 172-179 ◽  
Author(s):  
Olivo Omar Zanela ◽  
Hermilo Arturo Cabra ◽  
Guillermo Meléndez ◽  
Pablo Anaya ◽  
Frederic Rupprecht
Keyword(s):  
Bariatric Surgery ◽  
Economic Evaluation ◽  
Discrete Event Simulation ◽  
Discrete Event ◽  
Event Simulation
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