Introduction determining the model’s credibility: its advantages and disadvantages,

IntroductionThe following essay will examinethe effectiveness of Discrete Event Simulation (DES) and Monte Carlo Simulation(MCS) in two case studies.

It will pay close attention to the applicability andversatility of both techniques in each case study.  The case studies presented were chosen basedon the writer’s interests. First Case StudyIn the first case study selectedfor this essay the authors developed a model to investigate the financialstructure of a Public- Private Partnership (PPP) young-graduate housing projectin Hangzhou and its associated uncertainties (Xu et al., 2015).

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The researchersdeveloped their research methodology after the careful examination ofprevailing PPP models in top tier academic journals dealing with construction,management and engineering. Developing the research methodology was a longstrenuous process for the authors due to the complexities related to theproject. They found only a handful approaches had been created that identifiedthe exact financial structure of PPP based apartment construction (Xu et al., 2015).As a result the researchers opted to take a very conservative approach duringthe models construction phase. Ultimately, they chose to utilize a Monte CarloSimulation (MCS) that stresses the risk factors of young-graduate PPP housingproject over the construction and operations stages of the venture.

                The MCSmodel was evaluated through the interview of several experts from the private,government, and academic sectors. The interview process permitted the authorsto test the overall logic and applicability of the model in reality. Theexperts were given two criteria when determining the model’s credibility: itsadvantages and disadvantages, predictability, and reliability. The expertsfound the model was well-made and clearly understood the purpose of its applicability(Xu et al., 2015). Furthermore, they affirmed the model’s logical flowand reliability over other prevailing PPP models.                 The authors’selection of the MCS method can be further validated through the examination ofrelevant scholarly articles. The MCS is primarily utilized in the field financebut provides a method for answering any problem where analytical solutions arenot currently available.

 According toBerk and Podhraski (2017), the MCS is a reliable technique for determiningPPP projects “with uneven growth rates of demand and thus cash flow. Determiningthe demand for Chinese PPP housing projects is notoriously difficult given the publics’reluctance to accept public housing owned by the private sector. Consequently,PPP projects based in China are prime candidates for MCS since forecasting thedemand is problematic, further validating the authors’ method selection (Xu etal., 2015).

Although the selection of the MCSmethod was confirmed through a rigorous validation process the researcherscould have feasibly chosen another technique. For example, the Spanishconstruction firm Dragnados has been successfully utilizing discrete eventsimulations (DES) on multiple construction projects for several years.According to Martinez (2010), problems that are appropriate for DES techniquemeet the following criteria:1.      Involves a great deal of uncertainty due to thetime constraints placed on the project or the amount of materials utilized andprocessed. 2.      Logistically complex project with an integrateset of established rules and decisions. 3.

      The project has a series of interconnected partscontingent on overly complex start-up conditions in which resources with uniqueproperties work in concert to a set of dynamic rules Given the complex uncertainties associated with the PPPproject and the fact it meets all of the above criteria makes it a goodcandidate for the DES technique. Second Case Study The second paper selected forthis essay applies a simulation based method for the modelling of temporarystorage facilities that house resources at construction sites. The study analysesthe effects of storage facility size on construction projects and attempts tocreate a model that addresses storage space limitations (RazaviAlavi andAbouRizk, 2015).  The paper’sauthors embraced a hybrid simulation approach that combines a continuous simulation(CS) and discrete event simulation (DES) to correctly model the material flowand managerial activity. The approach incorporates all of the constraints a typicalconstruction project would face such as site layout, logistical issues, andmaterial management.

The hybrid approach that incorporates DES was taken due tothe uncertainties a vast majority of construction projects face.                 To testthe accuracy of the hybrid model they applied it to the layout process of a proposedtunnel project. Traditionally, tunnelling projects involve the flow of two materials:segments (concrete liners) and soil (RazaviAlavi and AbouRizk, 2015). The soil portioninvolves the excavation, storage, and removal of soil material from the projectsite. On other hand, the segment portion involves the storage, delivery, andinstallation of the segments on site. Since the soil and segment flows are occurringsimultaneously this creates a great deal of uncertainty for the project.

Forinstance trying to incorporate segment and soil flow rates, TBM penetrationrate, and resource implementation make it difficult to model the project. The DEStechnique was applied to the tunnelling duty at the operating level to determinethe tunnel production rate.                 Due tothe complex nature of the tunnelling project and hybrid approach utilized bythe researchers another simulation method could have feasibly been employed.  Given the complexity of the tunnelling projectthe MCS could have to been used as a substitute for one of other techniques.For instance, Isakkson and Stille (2005) constructed a MCS model to estimatethe construction times and cost outcomes of tunnelling projects. In order totest the robustness of the model it was applied to the Grauholz Tunnel projectin Switzerland. The time and cost estimations produced by the model werecompared with the actual estimation results obtained from the planning stagesof the tunnelling project.

The estimations produced from the MCS model were similarto the actual project results. This indicates that an MCS can successfullyemployed on a tunnelling project especially when a great degree of uncertainty ispresent. Conclusion This essay has successfully shown the applicability and versatilityof both techniques in the field of construction.  The techniques are useful tools whenattempting to simulate complex projects.