International Journal of Simulation and Process Modelling (12 papers in press)

Regular Issues

• Prediction of environmental factors in seafood cold chain transportation based on IAGA-ELM algorithm  
  by Yang Wang, Yujia Jin, Yinong Chen, Shenghui Zhao, Xu E 
  Abstract: Cold chain transportation is often used to ensure the quality of seafood. In order to reduce the impact of environmental factors on product quality during cold chain transportation, an environmental factor prediction method based on improved adaptive genetic algorithm (IAGA) and extreme learning machine (ELM) is developed to predict the environmental factors generated in cold chain transportation. The environmental factor data composed of the gases released in the decay mechanism of cold fresh seafood is collected for training ELM with fast training speed and strong generalisation ability. Furthermore, the prediction model of environmental factors in the process of seafood cold chain transportation is established. Because initial connection weights and threshold values of traditional ELM have the characteristics of randomness, IAGA is used to address this issue. Compared with the existing ELM, GA-ELM, AGA-ELM and other models, our experimental results show that the proposed model obtains higher prediction accuracy and lower error rate.
  Keywords: IAGA; ELM; cold chain transportation; environmental factors; prediction.
  
  
• Research on end-edge-cloud collaborative model of smart home system  
  by Shun-kai Lu, Bao-chuan Fu 
  Abstract: By introducing edge computing technology, an end-to-end cloud collaborative task scheduling model is built to provide computing power support for smart home systems. With the purpose of increasing the use rate of edge nodes and sharing the cloud computing pressure as well as meeting the demand of users for time delay as the constraint condition, tasks generated by users are analysed and unloaded to each edge node and cloud according to greedy algorithm. The edge nodes are pre-graded to reduce the global neglect of greedy algorithm when it comes to local optimal solution. The optimisation of setting edge node pair to reduce cloud platform pressure and edge node hierarchical unloading compared with traditional computing mode is verified by simulation.
  Keywords: edge computing; time delay; smart home; cloud computing.
  
  
• Presenting an efficient scenario to deal with the prevalence of COVID-19 in Iran using a system dynamics approach  
  by Vahideh Bafandegan Emroozi, Azam Modares, Pardis Roozkhosh 
  Abstract: The COVID-19 disease has adversely affected all countries in the world, due to its impact on public health and the lack of a basic solution. In this study, a model of the disease status in Iran is presented using system dynamics (SD). Even though static models that leverage mathematical programming and analytical models have been widely studied, simulation methods in the anticipation policies to deal with infectious diseases are scarce despite their potential. To this end, SD modeling is suitable to account for the dynamic and complexity of systems and supporting strategic decision-making. In this study, the SD method is used to model the behavior of variables such as the number of patients, population of deaths, recovered population, susceptible population, social distance, observance of health issues, and so on. Finally, to prevent comprehensive outbreak, three different scenarios are proposed and, the effect of the scenarios on the problem variables in dealing with this disease are investigated.
  Keywords: COVID-19; epidemic; health system; simulation; system dynamics; comprehensive outbreak; vaccination.
  
  
• Model for improving emergency room performance using a coloured Petri net  
  by Alvaro Caicedo Rolon, Gustavo Guerrero Gómez, Faustino Moreno Gamboa 
  Abstract: Emergency rooms are one of the most complex and vital areas of healthcare institutions, which have presented overcrowding, affecting the timeliness and quality of service. We designed a detailed patient flow model in the emergency room using the hierarchical timed coloured Petri nets. Then, we simulated the model to evaluate improvement scenarios considering physician staff planning, adjusting work schedules and increasing observation beds. The best scenario would reduce the average waiting times for triage II patients by 17.30% and 47.57%, and triage III by 33.49% and 43.49% for medical consultation in the office or the minor surgery room, respectively. In addition, the waiting time in observation and the rate of patients left without being seen by a physician would reduce by 92.45% and 74.67%, respectively. Finally, this model is a tool to support emergency room managers in making short, medium, and long-term decisions.
  Keywords: healthcare system; discrete event simulation; DES; decision-making; healthcare management; hospital logistics; emergency department.
  DOI: 10.1504/IJSPM.2022.10053527
   
  
• Numerical modelling of different types of Nanofluid used to enhance the thermal performance of automotive radiators  
  by Karaar Al-Araji, M.A. Aloussawi, Dhafer Hachim, Kareem Alwaan 
  Abstract: Nanofluids are used to reduce the amount of heat and to increase the thermal performance of the automotive engine. In this work, the effect of nanofluids on the thermal performance of automotive radiators has been studied numerically using the Comsol Multiphysics software V.5.4 on three types of nanofluid (Al2O3, CuO and MWCNT) at different volume concentrations of 0.5, 1.0, and 2%, and at different flow rates (4, 6, 8) L/min with inlet temperatures of (60, 70 and 80) oC. Results were compared with previous studies with high sobriety to verify the numerical analysis results. The results found an excellent convergence of 6.2% for experimental research and 7.6% for numerical studies. The results also showed that the best thermal performance is obtained by using MWCNT nanofluid. The highest percentages of improvement obtained in the Nusselt number were 25.83%, 42.37%, and 59.7% at volume concentrations of 0.5, 1.0, and 2%, respectively.
  Keywords: nanofluid; Comsol Multiphysics; heat transfer; MWCNT.
  
  
• Performance optimisation of the feed water system of a thermal power plant using stochastic Petri nets with comparative analysis using PSO  
  by Sudhir Kumar, P.C. Tewari 
  Abstract: This study applies the stochastic Petri nets method for the performance evaluation of the feed water system of a thermal power plant. The availability analysis of subsystems has been used to determine the maintenance priorities. Further, the particle swarm optimisation (PSO) technique has been applied for the comparative analysis and optimised results. A licensed software package is used to examine the effects of different failure and repair rates, as well as the availability of repair facilities, on the performance behaviour and availability of the system. An algorithm has been applied in MATLAB software for optimisation using PSO. On the basis of the availability matrices obtained by Petri nets a decision support system for maintenance order priority is proposed, which will help the maintenance personnel to identify the criticality among various subsystems and to plan the maintenance policies and schedule.
  Keywords: Petri nets; performance modelling; availability assessment; decision support system; feed water system.
  DOI: 10.1504/IJSPM.2023.10054083
   
  
• Process mining analysis to enhance systematic workflow of an IT company  
  by Parham Porouhan 
  Abstract: This study explores the application of Fluxicon Disco, a process mining tool, on an event log collected from an IT company. The analysis conducted using Fluxicon Disco provides insights into the following issues: identification of slow and time-consuming activities, abnormal activity behaviours, loops, repeated and redundant activities, abnormal clusters/variants, cases handled inefficiently, specific paths and relationships, congestions and bottlenecked areas, time intervals/gaps for cases with 'high priority', in addition to relationships and connections between task groups. The results of the analysis indicate that the software can identify inefficiencies and areas for improvement in the company's processes, providing valuable insights for process optimisation. The study concludes that the application of process mining tools such as Fluxicon Disco can significantly contribute to the identification and resolution of process-related issues in organizations. Eventually, the paper provides useful insights for researchers and practitioners interested in analysing business processes, process discovery and process optimisation.
  Keywords: process mining; data-driven analysis; systematic workflow; IT company; event log; slow activities; abnormal behaviour; redundancy; inefficiencies; process optimisation; task groups; process-related issues; business processes; process discovery.
  
  
• Comparing the performance of different geometric solutions for erosion problem of standard elbows in air-solid flow using CFD-DEM  
  by Davood Beyralvand, Farzad Banazadeh, Rasoul Moghaddas 
  Abstract: In many industrial applications, sand erosion wear is the main cause of equipment failure, particularly in the transferring pipeline fittings. In order to reduce the adverse consequences of erosion in bends, this work investigates the erosion of an elbow pipe due to the gas-solids turbulent pipe flow using computational fluid dynamics. The studied geometries included double T-plug, elbows with different curvature radius, elbows with different angles, T-plug and vortex chamber elbow. Results of the sensitivity analyses used to study the effects of the changes in the particle size/velocity, mass loading, erosion model and turbulence model on erosion rate revealed that long-radius elbow and double T-plug are good choices.
  Keywords: standard elbows; erosion; gas-solid flow; CFD-DEM; particle tracking.
  
  
• Prediction of electrical energy consumption of CONARC  
  by Parul Kota, Albin Rozario Samiraj, Sujoy S. Hazra 
  Abstract: Due to the complex nature and vast number of variables involved in the CONARC
  Keywords: CONARC®; Steel making; Electrical energy; Statistical Modelling; Machine learning.
  
  
• Reliability analysis of rice milling station via Gumbel Hougaard Family Copula  
  by Nafisatu Muhammad Usman, Ibrahim Yusuf 
  Abstract: This paper presents the availability modelling and performance analysis of a linear consecutive k-out-of-n systems of the milling section of a rice mill plant consisting of four subsystems, namely cleaning and destoning section, husking and paddy separation section, rice grading and polishing section and lastly sorting and bagging section. During operation, the system undergoes two possible states of operation namely, full capacity and failed state. Using Gumbel-Hougaard Family Copula, the state probabilities for the proposed schemes are obtained and system availability, reliability and MTTF are calculated. Numerical examples are presented to illustrate the results obtained and to analyse the effect of different system parameters. The finding of this paper will boost the efficiency of the system and will be useful for timely maintenance progress, decision-making, preparation and optimisation. Through Laplace transforms using regenerative point techniques, the first-order system of differential equations were formulated from the transition diagram and solved. Maple 18 software was used to perform the numerical computations. The performance of the system was assessed through the numerical results obtained.
  Keywords: availability; reliability; MTTF; probability; rice mill.
  
  
• Patient waiting time analysis in a multispecialty ophthalmic outpatient clinic using data analysis and discrete event simulation  
  by Shanmugam Prasanna Venkatesan, Lalwani Saurabh, Naveen Thomas, Sumanta Roy 
  Abstract: The demand for outpatient services is rapidly growing, resulting in multifaceted challenges due to capacity limitations. This research aims to analyse the patient waiting time in a multi-specialty ophthalmic outpatient clinic using data analysis and discrete event simulation (DES). The patient arrivals, the duration for pre-consultation and post-consultation services are highly uncertain. At first, a linear regression analysis is performed using electronic health record (EHR) log data, and the significant factors that affect patient waiting time are found. Further, a discrete event simulation model of the outpatient clinic is built using FlexSim Healthcare software (5.3) and validated. Improvement scenarios, namely: 1) adding resources; 2) introducing fixed interval appointment scheduling; 3) combining scenarios 1 and 2, are proposed for reducing the patient waiting time and evaluated. From the simulation results, it is inferred that scenario 3 reduces the average waiting time of the patients to 12.45 minutes from 38.37 minutes.
  Keywords: healthcare simulation; outpatient clinic; ophthalmology; data analysis; regression; waiting time.
  DOI: 10.1504/IJSPM.2023.10056150
   
  
• Study of vehicle dynamics response to collision in windrows of mine access roads through computer simulation  
  by Elyton Naves, João Lucas Diniz Oliveira, André Rebello Horta Novais 
  Abstract: The study presents an ore transport vehicle in simulated collision against the protection windrow (berm), located on the side of the roads, in order to prevent the vehicle from escaping in transit on the road. The work presents a study developed through computer simulation to validate the safety of access roads to mines owned by MRN. The objective is to dimension a windrow that it guarantees the safety of employees who travel with heavy-duty vehicles within the mine's operating fields. The computational simulations were carried out using the software EDEM and Motion View to simulate granular particles through the DEM methodology (Discrete Element Method) and the theory of vehicle dynamics, respectively. The information for the elaboration of the works were provided by MRN and complemented through scientific studies developed by the Naves Engenharia team. The results presented satisfactory data to the conditions required initially.
  Keywords: simulation; computer aided engineering; discrete element method; vehicular collision simulation.