OPTIMIZING PRODUCTIVITY RATE TO MINIMIZE OVERDRAFT INTEREST PAYMENT IN INFRASTRUCTURE CONSTRUCTION PROJECTS

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ahmed Abdelrady Okasha Mohamed Elnady ◽  
Parastoo Eivazi Ziaei ◽  
Ahmed Hammad
Keyword(s):  
Hybrid Model ◽  
Cash Flow ◽  
Construction Projects ◽  
Discrete Event ◽  
Road Construction ◽  
Good Opportunity ◽  
University Of Alberta ◽  
Event Simulation ◽  
Productivity Rate ◽  
The University

Winning a bid is a good opportunity for contractors that includes risks. After winning a project, contractors typically receive payments after two-three months of work completion that leads to negative cash flow (overdraft) throughout the duration of a project. Hence, contractors borrow from banks and pay monthly interests on the amount of overdraft they owe. To solve this problem, a hybrid model utilizing Discrete Event Simulation using SIMPHONY software, a special purpose simulation tool developed by the University of Alberta, accompanied by Markov Chain prediction technique. The developed hybrid model allows contractors to test different scenarios in search of the optimum productivity rate and payment arrangement to minimize negative cash flow. A case study utilizing a typical road construction project is used to test and validate the developed model and its ability to determine the optimum scenario. Results revealed that markup percentage and initial investment are two crucial factors to deliver the project successfully. In the harsh market, increasing the amount of cash to invest without a reasonable markup (at least 10%) will no longer make a profit. But, if the markup percentage could be increased by more than 15%, it will offer a chance to the contractor to make a profit and successfully deliver the project with initial investment reasonably low; and save a flexible productivity rate to finish the project within the schedule.

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 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.

scholarly journals The application of a hybrid simulation modelling framework as a decision-making tool for TPM improvement

2019 ◽  
Vol 25 (3) ◽  
pp. 476-498 ◽  
Author(s):  
Omogbai Oleghe ◽  
Konstantinos Salonitis
Keyword(s):  
Discrete Event Simulation ◽  
Hybrid Model ◽  
Discrete Event ◽  
Simulation Modelling ◽  
Hybrid Modelling ◽  
Content Type ◽  
Event Simulation ◽  
Modelling Framework ◽  
Field Notes

Purpose The purpose of this paper is to promote a system dynamics-discrete event simulation (SD-DES) hybrid modelling framework, one that is useful for investigating problems comprising multifaceted elements which interact and evolve over time, such as is found in TPM. Design/methodology/approach The hybrid modelling framework commences with system observation using field notes which culminate in model conceptualization to structure the problem. Thereafter, an SD-DEShybrid model is designed for the system, and simulated to proffer improvement programmes. The hybrid model emphasises the interactions between key constructs relating to the system, feedback structures and process flow concepts that are the hallmarks of many problems in production. The modelling framework is applied to the TPM operations of a bottling plant where sub-optimal TPM performance was affecting throughput performance. Findings Simulation results for the case study show that intangible human factors such as worker motivation do not significantly affect TPM performance. What is most critical is ensuring full compliance to routine and scheduled maintenance tasks and coordinating the latter to align with rate of machine defect creation. Research limitations/implications The framework was developed with completeness, generality and reuse in view. It remains to be applied to a wide variety of TPM and non-TPM-related problems. Practical implications The developed hybrid model is scalable and can fit into an existing discrete event simulation model of a production system. The case study findings indicate where TPM managers should focus their efforts. Originality/value The investigation of TPM using SD-DES hybrid modelling is a novelty.

scholarly journals Execution of VHDL Models Using Parallel Discrete Event Simulation Algorithms

VLSI Design ◽  
1994 ◽  
Vol 2 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Peter J. Ashenden ◽  
Henry Detmold ◽  
Wayne S. McKeen
Keyword(s):  
Discrete Event Simulation ◽  
Discrete Event ◽  
Register Transfer Level ◽  
Small Scale ◽  
Parallel Discrete Event Simulation ◽  
Event Simulation ◽  
Simulation Algorithms ◽  
Parallel Discrete Event ◽  
The University ◽  
Event Queue

In this paper, we discuss the use of parallel discrete event simulation (PDES) algorithms for execution of hardware models written in VHDL. We survey central event queue, conservative distributed and optimistic distributed PDES algorithms, and discuss aspects of the semantics of VHDL and VHDL-92 that affect the use of these algorithms in a VHDL simulator. Next, we describe an experiment performed as part of the Vsim Project at the University of Adelaide, in which a simulation kernel using the central event queue algorithm was developed. We present measurements taken from this kernel simulating some benchmark models. It appears that this technique, which is relatively simple to implement, is suitable for use on small scale multiprocessors (such as current desktop multiprocessor workstations), simulating behavioral and register transfer level models. However, the degree of useful parallelism achievable on gate level models with this technique appears to be limited.

Oddfellow's Orphanage by E.W. Martin

2012 ◽  
Vol 2 (2) ◽  
Author(s):  
Nicole Dalmer
Keyword(s):  
New York ◽  
Fairy Tales ◽  
Public Libraries ◽  
Discrete Event ◽  
Read Aloud ◽  
University Of Alberta ◽  
School Year ◽  
New Family ◽  
The Right ◽  
The University

Martin, Emily Winfield. Oddfellow's Orphanage. New York: Random House Children’s Books, 2012. Print. Emily Winfield Martin crafts a whimsical, imaginative read in her debut novel, Oddfellow’s Orphanage, that is sure to delight readers of all ages. As Delia, the newest member of the Oddfellow’s Orphanage quickly discovers, the members living at the orphanage are anything but ordinary. Under the guidance of Headmaster Oddfellow Bluebeard, her new family includes an onion-headed boy, a blue tattooed girl, a child-sized hedgehog, and a family of three dancing bears. While Delia is unable to speak and must instead write to communicate, she is immediately accepted into her new family. The oddities and peculiarities of each of the children residing at the orphanage are matched in the school classes they take, including Professor Flockheart’s F. T. Studies (fairy tales and folktales) and Professor Silas’ cryptozoology class. In this rather unorthodox orphanage, the school year passes with one quirky adventure after another. Each bizarre yet entertaining escapade allows the author to develop each character’s personality as well as friendships between the children, endearing the reader to each of the orphans. With Haircut Day, a grand picnic, a fieldtrip to see the Great Comet and an expedition to locate lake M.O.N.S.T.E.R.S. (Mysterious or Nonexistent Subjects Thoroughly Examined Really Scientifically), nothing is ever ordinary at Oddfellow’s Orphanage. While comical and curious, the story, at times, appears to unfold in isolated vignettes, with each chapter a discrete event, making for less-than-smooth plot continuity. Quite impressively, the author manages to pepper the story with an appropriate amount of bizarre and peculiar elements, never once does the plot appear to be overly outlandish. While the writing itself is sweet and simple with perfectly proportioned chapters, lending itself to a fantastic first reader or a read-aloud story, it is Martin’s illustrations that accentuate the writing and highlight the whimsy found within the pages. The soft, sepia-coloured pencil drawings that appear on nearly every page give off a vintage aesthetic and confer just the right amount of detail to the story, allowing the reader to invent and imagine the rest. With overarching themes of acceptance and perseverance, both girls and boys will fall in love with the charming and unique characters and the impressive illustrations. Highly recommended for elementary school libraries as well as public libraries. Highly recommended: 4 out of 4 starsReviewer: Nicole Dalmer Nicole Dalmer is a Public Services Librarian at H.T. Coutts Education & Physical Education Library at the University of Alberta. She is interested in health literacy, pinball, and finding the perfect cup of coffee to accompany a good read.

Dynamics of workforce skill evolution in construction projects1This paper is one of a selection of papers in this Special Issue on Construction Engineering and Management.

2012 ◽  
Vol 39 (9) ◽  
pp. 1005-1017 ◽  
Author(s):  
Amin Alvanchi ◽  
SangHyun Lee ◽  
Simaan M. AbouRizk
Keyword(s):  
Construction Projects ◽  
Discrete Event ◽  
Special Issue ◽  
Construction Engineering ◽  
Event Simulation ◽  
Hr Management ◽  
Simulation Based ◽  
Development And Validation ◽  
Selection Of ◽  
Sd Model

Construction projects are usually labour intensive, and human resource (HR) issues contribute significantly to a project’s final costs. From this perspective, a tool that can help construction managers reduce their HR costs can potentially generate improvement in the project cost. In this paper we propose a simulation-based approach that sheds light on the dynamics of workforce skill evolution as the project progresses, thereby assisting construction managers in adjusting their HR policies. The proposed approach uses a system dynamics (SD) simulation model that dynamically tracks the effects of alternative HR policies. After the development and validation of the SD model, the SD model is extended to capture operational details and their interaction with workforce skill evolution, adopting a hybrid SD and discrete event simulation (DES). The hybrid model has been applied to an experimental case of structural steel fabrication projects, in which we demonstrate that there is a considerable room for cost-saving in HR. The hybrid modeling approach introduced in this paper can be employed by construction managers for possible improvements in HR management, as well as researchers for an in-depth understanding of the dynamics in workforce skill evolution.

scholarly journals A study on Efficient Modelling in Higher Education Academic Workforce Using Simulation

2021 ◽  
Vol 2 (6) ◽  
pp. 7-14
Author(s):  
Nethal K. Jajo ◽  
Shelton Peiris
Keyword(s):  
Higher Education ◽  
Operations Research ◽  
Discrete Event ◽  
Workforce Planning ◽  
Policy Changes ◽  
Event Simulation ◽  
Education Academic ◽  
Academic Workforce ◽  
The University

This paper shows how the Operations Research (OR) tools (in modelling and simulation) can be modified, applied in planning and their understanding of any long-term impacts due to sudden policy changes. The proposed approach is particularly useful to investigate the movements of the university academics and their impacts on changes in research, research funding, teaching and services as they are the integral parts of the career at any level. We argue that the Discrete Event Simulation (DES) approach can be used to model such dynamics in Higher Education Academic Workforce Model (HEAWM) and show that it can provide a comprehensive projection of future requirements within the context of career progression. Consequently, this HEAWM allows universities to interrogate factors influencing the academic workforce planning as this process often requires the new attributes to be tracked in the model which is difficult with other OR models. It is shown that this approach is easy to apply via DES and creation of the corresponding HEAWM provides better understanding of the factors that will influence the future workforce than the existing results.

Implementing lean six sigma and discrete-event simulation for tutoring operations in higher education institutions

2019 ◽  
Vol 10 (4) ◽  
pp. 909-927 ◽  
Author(s):  
Sandra L. Furterer ◽  
Kellie Schneider ◽  
Michael B. Key ◽  
Daniel Zalewski ◽  
Michael Laudenberger
Keyword(s):  
Discrete Event Simulation ◽  
Six Sigma ◽  
Discrete Event ◽  
Wait Time ◽  
Lean Six Sigma ◽  
Content Type ◽  
Event Simulation ◽  
The University ◽  
The Impact ◽  
University Of Dayton

Purpose The purpose of this study is to improve the utilization of walk-in tutors at the University of Dayton. Design/methodology/approach This paper discusses the application of mixed methods participatory action research with the use of the lean six sigma (LSS) define-measure-analyze-improve-control (DMAIC) methodology combined with discrete event simulation to improve the tutoring processes at the University of Dayton. Findings The impact of these improvements provided a great balance between tutor utilization and student wait time, and as a result, an increase in pay was negotiated for tutors. Additionally, two schools within the University, Engineering and Business, have seen the value of the tutoring for their students and have provided additional financial support for tutoring services. Specifically, these schools now have dedicated by-appointment tutors for their students. Originality/value Incorporating simulation within the LSS methodology provides a “prototype” simulation of the potential solutions prior to changing the process in the real world. This approach can minimize the risk of implementing solutions that are costly or ineffective. The improvement of increased tutor pay helped to demonstrate the university’s commitment to tutors and tutoring. Through continuous improvement efforts, the tutoring department has tripled the number of courses that they support through these enhanced relationships, improved utilization and the overall culture and work environment. The LSS methodology and tools combined with discrete event simulation can be used as a guide for improving other repetitive processes within the university.

EVALUATION OF SIMULATION TECHNIQUES FOR MODELING PROGRESSION OF CONSTRUCTION CLAIMS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Mohammad Barakat ◽  
Hiam Khoury ◽  
Mohamed-Asem Abdul-Malak
Keyword(s):  
Construction Projects ◽  
Discrete Event ◽  
Hybrid Approach ◽  
Simulation Models ◽  
Complex Problem ◽  
Weak Links ◽  
Agent Based ◽  
Event Simulation ◽  
Simulation Techniques ◽  
Potential Applicability

The unstructured and dynamic nature of construction projects and the on-site work complexities have been inevitably leading to claims. These evolve according to a staged mechanism set forth in the adopted conditions of contracts. More specifically, claims might progress expeditiously or drag depending on the nature of the applied mechanism and the behavior and interaction among contractual parties. As such, this complex problem of claim progression, which entails a lot of parameters and variables, is addressed in detail in this paper by resorting to three simulation techniques namely: (1) Discrete-Event Simulation (DES), (2) Agent-Based Modeling (ABM), and (3) System Dynamics (SD). The purpose behind this study is two-fold: (1) capturing and visualizing, through three different simulation models, the dynamic and interaction among the different entities as claims are progressing and defining the weak links hindering the efficiency improvement of such a process, and (2) comparing DES, ABM, and SD simulation approaches, using choose-by-advantage technique, and evaluating the advantages and drawbacks of each when studying the progression of claims. Results of all approaches are presented and analyzed followed by a discussion of the effectiveness of each simulation technique and the potential applicability of a hybrid approach in modeling the progression of claims.

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