scholarly journals Discrete-Event Simulation versus Constrained Graphic Modelling of Construction Processes

2014 ◽  
Vol 2 (1) ◽  
pp. 13
Author(s):  
Ian Flood ◽  
Valeh Nowrouzian
Keyword(s):  
Discrete Event Simulation ◽  
Critical Path ◽  
Discrete Event ◽  
Project Planning ◽  
Construction Simulation ◽  
Qualitative Comparison ◽  
Event Simulation ◽  
Advantages And Disadvantages ◽  
Planning And Control ◽  
Linear Scheduling

Effective construction project planning and control requires the development of a model of the project’s construction processes.  The Critical Path Method (CPM) is the most popular project modelling method in construction since it is relatively simple to use and reasonably versatile in terms of the range of processes it can represent.  Several other modelling techniques have been developed over the years, each with their own advantages and disadvantages.  Linear scheduling, for example, has been designed to provide highly insightful visual representations of a construction process, but unfortunately is largely incapable of representing non-repetitive construction work.  Discrete-event simulation is generally agreed to be the most versatile of all modelling methods, but it lacks the simplicity in use of CPM and so has not been widely adopted in construction.  A new graphical constraint-based method of modelling construction processes, Foresight, has been developed with the goal of offering the simplicity in use of CPM, the visual insight of linear scheduling, and the versatility of simulation.  Earlier work has demonstrated the modelling versatility of Foresight.  As part of a continuing study, this paper focuses on a comparison of the Foresight approach with discrete-event construction simulation methods, specifically Stroboscope (a derivative of CYCLONE). Foresight is shown to outperform Stroboscope in terms of the simplicity of the resultant models for a series of case studies involving a number of variants of an earthmoving operation and of a sewer tunnelling operation.  A qualitative comparison of the two approaches also highlights the superior visual insight provided by Foresight over conventional simulation, an attribute essential to both the effective verification and optimization of a model.

scholarly journals МОДИФІКАЦІЯ МЕТОДУ УРАХУВАННЯ РИЗИКІВ ПРОЕКТУ РОЗРОБКИ ТЕХНІЧНИХ СИСТЕМ

2019 ◽  
pp. 55-62
Author(s):  
Анастасія Дмитрівна Морікова ◽  
Ольга Костянтинівна Погудіна
Keyword(s):  
Discrete Event Simulation ◽  
Discrete Event ◽  
Aircraft Engine ◽  
Systems Development ◽  
Development Project ◽  
Project Planning ◽  
Data Matrix ◽  
Improved Method ◽  
Event Simulation ◽  
Technical Systems

Subject research paper is the development of technical systems. The aim is to improve the quality of planning the basic characteristics of technical systems development project. Objective is to analyze the works in the area of risk when planning projects, justified the choice of method of planning the main indicators of the project taking into account the uncertainties and risks, developed and tested method of accounting for risks of interference in the project of development of technical systems on the example of the development of an aircraft engine. Used theoretical methods are: the method of discrete-event simulation for obtaining histograms of cost and time of development of technical systems, the method of calculating the cumulative damage risk events, the model matrix representation as a mathematical device for the presentation and study of interference risks. We obtained the following results. Analysis of existing work and standards in the field of risk management, reviewed the existing information system of risk-based project simulation and variability of the project. On the basis of the detected restriction provides an improved method for the basic parameters of the project planning. The process of identification and the following categories of risk identified: the expectations, cost, appearance of additional work, return. Given the typology of interference risks formalized the concept of additivity, synergy and cannibalization (negative synergy). An information subsystem that preparesinput to project performance simulation taking into account the risks, where the use of the data matrix relationship likelihood of risks and interference effects manifestations of risk events. Developed information subsystem was tested on calculation Show cost and runtime stages of research works on the development of an aircraft engine. Scientific novelty of the results is as follows: improved method of discrete-event simulation account of technical systems development project risks by adding a formalization of interference risks.

scholarly journals Discrete-Event Simulation to Model the Thrombolysis Process for Acute Ischemic Stroke Patients at Urban and Rural Hospitals

2021 ◽  
Vol 12 ◽  
Author(s):  
Tessa Bulmer ◽  
David Volders ◽  
John Blake ◽  
Noreen Kamal
Keyword(s):  
Conceptual Framework ◽  
Discrete Event Simulation ◽  
Critical Path ◽  
Discrete Event ◽  
Rural Hospitals ◽  
Time Duration ◽  
Event Simulation ◽  
Maximum Reduction ◽  
The Impact ◽  
Test Scenarios

Background: Effective treatment with tissue plasminogen activator (tPA) critically relies on rapid treatment. Door-to-needle time (DNT) is a key measure of hospital efficiency linked to patient outcomes. Numerous changes can reduce DNT, but they are difficult to trial and implement. Discrete-event simulation (DES) provides a way to model and determine the impact of process improvements.Methods: A conceptual framework was developed to illustrate the thrombolysis process; allowing for treatment processes to be replicated using a DES model developed in ARENA. Activity time duration distributions from three sites (one urban and two rural) were used. Five scenarios, three process changes, and two reductions in activity durations, were simulated and tested. Scenarios were tested individually and in combinations. The primary outcome measure is median DNT. The study goal is to determine the largest improvement in DNT at each site.Results: Administration of tPA in the imaging area resulted in the largest median DNT reduction for Site 1 and Site 2 for individual test scenarios (12.6%, 95% CI 12.4–12.8%, and 8.2%, 95% CI 7.5–9.0%, respectively). Ensuring that patients arriving via emergency medical services (EMS) remain on the EMS stretcher to imaging resulted in the largest median DNT improvement for Site 3 (9.2%, 95% CI 7.9–10.5%). Reducing both the treatment decision time and tPA preparation time by 35% resulted in a 11.0% (95% CI 10.0–12.0%) maximum reduction in median DNT. The lowest median and 90th percentile DNTs were achieved by combining all test scenarios, with a maximum reduction of 26.7% (95% CI 24.5–28.9%) and 17.1% (95% CI 12.5–21.7%), respectively.Conclusions: The detailed conceptual framework clarifies the intra-hospital logistics of the thrombolysis process. The most significant median DNT improvement at rural hospitals resulted from ensuring patients arriving via EMS remain on the EMS stretcher to imaging, while urban sites benefit more from administering tPA in the imaging area. Reducing the durations of activities on the critical path will provide further DNT improvements. Significant DNT improvements are achievable in urban and rural settings by combining process changes with reducing activity durations.

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