International Journal of Simulation and Process Modelling (38 papers in press)
Lightweight design of semitrailer based on topology optimisation and response surface methodology
by Shuwen Zhou, Jichao Xu
Abstract: To improve the fuel economy and transportation efficiency of semitrailers, this paper conducts a lightweight study on a semitrailer frame. This paper mainly uses the finite element method and combines topology optimisation and response surface method to optimise the suspension and frame. After the optimisation analysis, the best installation size of the suspension is finally obtained, and the weight of the frame is reduced by 507.8 kg to meet the material strength, which achieves a good lightweight effect. The lightweight method of the semitrailer proposed in this paper can provide a feasible solution for the lightweight of road transport vehicles.
Keywords: semitrailer; finite element analysis; lightweight; topology optimisation; response surface methodology.
Thermal conductivity of bimetal Al-Cu: molecular dynamics simulation
by Junaidi Syarif, Khaled Badawy, Mohamed Hisham, Hussien Hussien
Abstract: In this study, the phonon thermal conductivity of bimetal Al-Cu was modelled using molecular dynamics. The conductivities of pure Cu and Al were calculated and discussed first to verify the adopted methodology. The behaviour of the heat current autocorrelation function was discussed for the two pure metals and the bimetal. The values of thermal conductivity at different temperatures for the pure metals were reported and the results were correlated to similar computational works. The thermal conductivity was found to drop as the temperature increased. The bimetal Al-Cu thermal conductivity and the variation with temperature were reported. It was found that the bimetal Al-Cu has a very low conductivity compared with the pure metals. It was found that the drop in thermal conductivity was due to an increase in lattice defects and distortions arising from the bimetal interface. The drop in thermal conductivity as the temperature increases still holds and follows a linear relation.
Keywords: Green Kubo relation; phonon; lattice distortion; interface.
Modelling of the balance between energy efficiency and economy and simulation analysis in electric gas production technology
by Jiajun Wang, Yahui Wang, Wenjie Qi
Abstract: The simulation optimisation analysis of electric gas production technology (P2G) was conducted by an exergy analysis method. The energy efficiency equation of electrolysis water and methanation in P2G was established. The net present value (NPV) method was used to analyse the economy of P2G, and the economy equation of P2G was established. The balance between economy and energy efficiency of the system was adjusted using the optimisation weight coefficient. The optimisation model of balance between energy efficiency and economy in P2G and its constraint equation were established, and the optimisation simulation analysis was carried out by combining Lagrange relaxation and branch-and-bound method. The analysis results have shown that the profit of the P2G is affected by the efficiency of electrolysis water and methanation as well as equipment investment. By optimising the P2G process and investing in the equipment reasonably, the maximum economic benefit of the P2G system can be obtained.
Keywords: electric gas production technology; exergy analysis; energy efficiency; simulation.
Relative domain modelling based on a ship's group situation in restricted waters
by Xiaoyuan Wang, Yifei Sun, Gang Wang, Quanzheng Wang, Guowen He
Abstract: A ship's domain is the area around the ship that shouldnt be entered by other ships. In existing research methods, complex environmental factors or ship factors were not fully considered, which lead to the result that the dynamic change of the whole navigation environment couldnt be effectively or comprehensively reflected. In this paper, based on analysis of the complexity of a ship's group situation in restricted waters, a relative domain model was established to adapt to the current navigation environment. the influence of interfering ships and quay walls on the target ship was considered, and navigation dynamics of the target ship and interfering ships were both analysed. The model was verified through the combination of real ship and simulation experiments, and the results show that the model can accurately reflect the degree of navigation hazard of a ship in restricted waters, and it can provide an effective reference basis for collision avoidance of unmanned ships.
Keywords: domain; modelling; simulation; ship's group situation; restricted waters; collision risk.
Performance evaluation of ODMAC protocol for WSNs powered by ambient energy
by Zohra Hmidi, Laid Kahloul, Saber Benharzallah, Nadia Hamani
Abstract: Designing a good MAC protocol remains a challenge. Such a protocol has to guarantee access to the medium while reducing energy consumption. With the appearance of Energy Harvesting-Wireless Sensor Networks (EH-WSNs), energy is no longer a problem but the challenge now is that each sensor remains in its energetically sustainable state as much as possible. This paper proposes a formal study of On Demand MAC (ODMAC) one of the well-known protocols proposed for EH-WSNs. An analysis through statistical model checking is made where properties that guarantee the protocol's correctness are verified and a performance evaluation of important aspects is achieved.
Keywords: energy harvesting wireless sensor networks; energy neutral operation state; ENO-Max state; on-demand medium access control protocol; duty cycle; performance evaluation; formal verification.
Pricing the passages related to traffic restriction by using novel genetic algorithms
by Farzaneh Darroudi, Ali Ala, Mahdi Yousefi Nejad Attari
Abstract: Nowadays, a lot of transport-related data for traffic modelling are available. Many measures have been taken, which can be referred to as pricing related to traffic restrictions. According to Economic Standards in Pricing Traffic Limitation Routes, consumers who cross high-traffic routes must pay a fee proportional. The sum between the final social fee and the typical fee should optimise social network income. Therefore, in this article, we have tried to use the genetic algorithm as one of the meta-heuristic algorithms and admit more agents and classification on users, vehicles, and the combination of techniques applied in earlier investigations, an effective measure in to reduce and control traffic in busy thoroughfares. Also, using the genetic algorithm and the Frank-Wolfe algorithm adapted to the studied problem, the optimal price of the roads in the traffic constraint has been modelled. An example is used at the end of the article to implement the model.
Keywords: road pricing; Frank-Wolfe algorithm; two-level programming; traffic plan passages; genetic algorithm.
Software connector as software process
by Ahcene Menasria, Mourad Oussalah, Abdelkrim AMIRAT, Halima BAHI
Abstract: In component-based architectures, interest has often been focused on the components.
Recent applications are becoming more and more communicative, often reaching equivalent proportions between the interaction and functional parts. This study is interested in explicit connectors by proposing a rich semantic connector to model and implement complex communications in heterogeneous environments. We present a new structure of the connector and model its behaviour through a software process. We no longer consider it as a software product or artefact but rather as a communication process. The connector is treated as a first-class entity with the same degree of citizenship as a component. This research concentrated on the motivations and benefits of first-class connectors and some connector-centric works to arrive at
the proposed solution through a Meta-model illustrated by a case study using SPEM profile.
Keywords: software architecture; software process; software connector; meta-modelling; SPEM profile.
Research on inlet structure optimisation and numerical simulation of a three-phase separator
by Guorong Liu
Abstract: Three-phase separators are increasingly used in fields such as the pretreatment of oilfield produced fluids and the treatment of oily sewage in the chemical production process. As the core component of the three-phase separator, the inlet structure can make the relatively stable flow field obtained by the separator provide strong guarantee performance for subsequent separation. A better inlet structure can improve the separation effect of the separator to a certain extent. In this paper, the fluent software is used to numerically simulate the entrance structure of the three-phase separator. Through the analysis of different types of entrance structures, the general rules are summarised and the entrance structure of the three-phase separator is designed. Finally, combined with related research results, a bottom cylindrical inlet structure was developed and designed to improve the rectification performance of the inlet structure and effectively prevent the blocking of the distribution cylinder from occurring.
Keywords: inlet structure; three-phase separator; gravity sedimentation; numerical simulation.
Modelling of aerosol trajectories in a mechanically ventilated study room using computational fluid dynamics in light of the COVID-19 pandemic
by R. M. P. S. Bandara, W. C. D. K. Fernando, R.A. Attalage
Abstract: Millions of people have been infected globally owing to the COVID-19 pandemic and spread of the disease indoors has become a challenging issue. In this context, this study focused on modelling the trajectories of virus-laden aerosols in a study room by the computational fluid dynamics approach under four mechanically driven ventilation strategies: cavity flow, displacement flow and two cases of mixing flow. Modelling was conducted by coupling discrete phase model with the continuous phase during simulations. Mixing flow case 1 proved to be the safest strategy as the virus-laden aerosols leave the room in a single-pass without exposing the occupants. In displacement flow and mixing flow case 2 ventilation, aerosols get entrapped in the supply air stream, causing heavy circulation while exposing many occupants. The study opens up new avenues for an extensive analysis on establishing an optimal ventilation solution in order to mitigate the spread of COVID-19 indoors.
Keywords: COVID-19; aerosols; infection; trajectories; modelling; mechanically driven; ventilation strategies; computational fluid dynamics.
Design, simulation and fabrication of silicone rubber colonoscope tip for medical application
by Puneet Kumar Singh, Pankaj Kumar Shrivastav, Chimata Murali Krishna
Abstract: Colonoscopy is major tool to detect colon abnormality and colon cancer in initial stages. The colonoscope tip designed in this research work is made of silicone rubber, which is hyperelastic in nature in order to achieve distal end flexibility and comfort for patients. ABAQUS 2020 software is used for designing the colonoscope tip. After inputting the necessary data, the developed colonoscope tip is simulated by applying pneumatic pressure in three holes provided at 120 apart. A central hole is also provided for camera, biopsy tools etc. Thereafter, the designed colonoscope tip is manufactured and experiments are conducted using an experimental setup. The pneumatic air from a compressor is applied to the fabricated silicone colonoscope tip via hoses with a pressure regulator and a pressure sensor mounted on them, and displacement of the tip is measured. The experimental results obtained are quite close to the simulated results and thus the simulated results are validated.
Keywords: colonoscope; finite element method; ABAQUS; simulation; experimental setup.
Integrated lean manufacturing tools and discrete event simulation to examine the improvement in air conditioner split units production lines
by Abdulaziz Alkabaa
Abstract: In this article, lean tools of value stream mapping, line balancing, and root cause analysis are implemented in the production line of an air conditioner manufacturing plant aiming to improve and enhance productivity. The National Institute for Occupational Safety and Health (NIOSH) lifting guidelines and activity charts are applied to assess and improve material handling processes. The lean system tools are represented using discrete event simulation. Existing and improved systems are compared using performance criteria such as idle time, production capacity, machine utilisation, and average completion time. The lean tools show significant improvements in the assembly line by increasing the system utilisation from 71% to 87%. The proposed efficient material handling reduces the processing time by 20%. The activity chart reduces the processing time by 15.6%. Compared with the existing production processes, the proposed lean tools save 35% of the used resources and significantly improve the production capacity by 33%, and reduce the idle time by 65% and the average completion time by 38%. The proposed lean tools can be used and applied to increase the productivity and profitability of such industries.
Keywords: air conditioner split unit; lean system; simulation assembly line; NIOSH; productivity improvement; SIMIO; ergonomic risk assessment; discrete event simulation.
Modelling and simulation of the urban rail transit operation system based on system dynamics
by Liang Xue, Shengchuan Zhao, Jingyao Li
Abstract: Based on theories of systems engineering, the present study analyses the correlations between the variables in the urban rail transit operation system, and constructs a system dynamics model for the system. With the historical data of the urban rail transit system in Chengdu City, Sichuan Province in China as the basis, this study adjusts the variables of the four subsystems in the urban rail transit network and simulates three urban rail transit policy scenarios on the proposed model to estimate the dynamic changes in the major indicators for the operation of the urban rail transit network. The simulation result reveals that adopting different policies according to the development stages of the urban rail transit network can improve the contribution of urban rail transit services to improvement of urban transportation, enhance the performance and maximise social benefits of urban rail transit operators.
Keywords: urban rail transit; operation system; system dynamics; modelling.
Modelling and simulation of vaccine distribution: a COVID-19 situation
by M.S. Narassima, S.P. Anbuudayasankar, K.S. Balaji, B. Ramasubramanian
Abstract: Ever since the onset of COVID-19, the healthcare fraternity and supply chains have faced severe disruptions like never before. The higher transmission rate of the virus has spread it worldwide. Vaccination is an inevitable phase to curtail the spread of the pandemic. The present study aims to develop an agent-based model to explain the distribution network of the vaccine. Grey relational analysis has been carried out to rank different states of India based on the critical variables that govern the transmission of the virus. This would help the policymakers rationally to distribute the vaccines across different places. Further, sensitivity analysis has been performed with ten scenarios to compare the effects of positive and negative events, word of mouth, and the number of sessions on the distribution of vaccines. Increasing the sessions conducted per day from 163.33 by 40 and 80 increased the proportion vaccinated by 38.32% and 73.89%, respectively.
Keywords: COVID-19; agent-based modelling; vaccine distribution; grey relational analysis; cold chain management.
Using discrete event simulation to optimise cementing resources: a case study analysis using a call-out strategy for onshore rigs
by Mohammed K. Watfa, Maclean Dsouza
Abstract: While drilling oil and gas wells, multiple rigs are moved from one location to another for drilling and finalising new wells along the way. A standard resource configuration is to assign one cementing package for each rig. However, owing to the economic crisis experienced in the oil and gas industry in 2008, 2015 and recently due to the COVID-19 pandemic in 2020, companies are pushed to decrease costs efficiently. A simulation method is studied and developed in this paper to close the gap between the operations research and the implementation of a call-out strategy, which is reflected in the optimisation and resource capacity planning of the capital intensive, high pressure cement units. The objectives of this study are to study the economic implications of the call-out strategy and develop a discrete-event simulation model for the evaluation of call-out strategies alternatives to improve operational efficiency while minimising non-productive time.
Keywords: call-out strategy; cementing unit resources; operations research; drilling rigs; arena; optimisation; discrete event simulation.
Dynamic optimisation of elevators using biometric identification systems
by Eugeniu Cozac, Dmitry Gura, Alexey Bityutskiy, Sergei Kiselev, Anastasia Repeva
Abstract: The research focused on developing a real-time monitoring algorithm for elevators in residential towers. The study employed methods, models, and software tools to build intelligent real-time decision-making systems. A model for the elevator setting process was implemented through a Markov decision-making process. The theory of mass service was applied to describe the model of elevator operations. Passenger waiting time patterns at some levels of the towers have been established. A mathematical model for managing passenger flows through the elevators of a high-rise building in real-time using facial recognition identification technology has been developed. In test mode, a face-recognition elevator control system has been installed in 4 elevators. Results from experiments and theoretical calculations were statistically processed in Statistica and MS Excel software. The proposed solution allows optimizing numerous elevator systems with a constantly evolving control algorithm tailored to the customer's preferences.
Keywords: lifting facility; Markov process; mathematical model; traffic fluctuations; biometric data.
Service level analysis for an automotive prototype manufacturing company through the application of discrete event modelling and simulation.
by Karen García-Orozco, Ariana Gazcon-Rivera, Anna De León, Jenaro Nosedal-Sanchez
Abstract: This study addresses modelling and simulation as a tool for the analysis and evaluation of the design and manufacturing process of automotive prototypes. The application of these tools allows to visualise the process from a broader perspective and identify the downtimes that induce high variability to the process. Through the implemented simulation, the process cycle time is estimated given a certain level of service for each family of sequences identified in the sample. These results provide a quantitative reference of the response time according to the desired level of service for the process in general. In addition, an improvement scenario is provided through the implementation of a control monitor (KPI) in the critical activities that induce high variability to the process, which allows a 39% reduction in the magnitude of the lead times.
Keywords: supply chain; business analytics; discrete event simulation; Petri networks; CPN tool.
Spatial-temporal monitoring risk analysis and decision-making of Covid-19 distribution by region
by Leandro Pereira, Jorge Correia, José Sequeiros, José Santos, Carlos Jeronimo
Abstract: The purpose of this study is to model, map and identify why these areas present a completely different dispersion pattern, as well as creating a risk model, composed by variables such as probability, susceptibility, danger, vulnerability and potential damage, that characterise each of the defined regions. The model is based on a risk conceptual model proposed by Bachmann and Allg
Keywords: Covid-19; spatial temporal; risk analysis; chaos theory; gravity model.
Energy efficiency optimisation modelling for security robots by edge computing
by Muchun Zhou, Baochuan Fu, Baoping Jiang
Abstract: Mobile robots with rich sensors accomplish many computation-intensive tasks which account for a large proportion of the total energy consumption, thus affecting the service life of their batteries. In the case of analysing real-time video data and a large amount of sensor data, offloading a numerous intensive computing tasks to edge servers has become an extensive solution. This paper proposes a system model containing multi-robot terminals and multi-edge servers which uses a simulated annealing algorithm based on exchanging two different edge servers. This algorithm realises energy efficiency optimisation for security robots under minimum latency and power limitation by offloading partial computation-intensive tasks to edge servers. The feasibility of the proposed algorithm is also verified by the simulation results.
Keywords: edge computing; security robot; computation offloading; energy efficiency optimisation.
Experimental research and simulation verification of recycling process of heat transfer oil
by Guorong Liu
Abstract: Heat transfer oil will inevitably deteriorate after long time use, leading to insoluble acetone in hot medium oil gradually accumulating and seriously exceeding the standard. Therefore, extending the service life of heat transfer oil is an important means to improve economic benefits. In this experiment, a solvent extraction settlement method was used to remove insoluble acetone. By designing a set of extractive settlers, sedimentation experiments were carried out with different solvents; moreover, the insoluble acetone content, kinematic viscosity and neutralisation value of the extracted heat transfer oil were determined, using the computational fluid dynamics method to verify the effect of the asphalt settlement separation tank by numerical simulation. The experiments were validated by measuring the extraction effects of different solvents. The results have important implications for industrial production.
Keywords: heat transfer oil; insoluble acetone; extraction sedimentation; orthogonal test; numerical simulation.
Special Issue on: ISM 2019 New Challenges and Solutions for Industry 4.0 and Smart Manufacturing
Blockchain-based solutions for agri-food supply chains: a survey
by Giovanni Mirabelli, Vittorio Solina
Abstract: In recent years, interest in blockchain technology has grown considerably, owing to its multiple properties, such as transparency, immutability, traceability, and security. Considering the significant number of recently published contributions about the use of blockchain-based solutions in the agri-food sector, in this paper we aim to collect and catalogue them. The main purpose is the identification of research trends and possible barriers to the large-scale spreading of this disruptive technology. Through a well-structured four-step research methodology, we systematically review 48 papers. The main result is that blockchain can be used not only to ensure complete food traceability, but also to protect workers' rights, limit the power of supply chain intermediaries, protect market prices, and enable reward mechanisms for the development of sustainable initiatives. However, there are still some open issues that limit its large-scale diffusion: lack of shared standards, limited number of real case studies, resistance by stakeholders, and restricted scalability.
Keywords: blockchain; agri-food supply chain; food traceability; internet of things; smart contract.
Construction logistics: a simulation case study to improve performance process
by Kamal Jaafar
Abstract: Logistics in construction in general is an old topic, which has been researched and studies by many scientists, engineers, and researchers. However, little attention was given to logistics management in the precast industry and was relatively ignored, especially in the United Arab Emirates (UAE), compared with the conventional construction industry (cast in-situ). This paper will talk in details about the forgotten part in construction logistics, which is the precast construction logistics management: specifically, the management of the precast stockyard layout in the precast concrete products industry. Designing an effective precast stockyard with effective storage and structural precast element retrieval is a very complex process. The complexity is because of the massive heavy precast elements products, unique lifting and tilting requirements, and the large number of panels produced and stocked. Thus, the paper will discuss how to ensure efficient storage and dispatch of precast elements, ease of rotation of precast elements within the precast stockyard, and a smooth precast element retrieval process from any stockyard. In addition, the paper will show how an effective stockyard layout can reduce the dispatch time, loading time, and queuing time of the precast elements within the stockyard. Finally, the paper will include simulation modelling using ARENA software to optimise, design, and test the new stockyard layout that we established and compare it with the current status of the precast stockyard. A 'what if' analysis will be implemented from the simulation model in order to cover various stockyard conditions, such as increased product production in the future.
Keywords: logistics; process optimisation; ARENA; stockyard management; construction.
Special Issue on: I3M2020/ISM2020 Smart Interaction for the 4.0 Domains Modelling and Simulating the Content of the Future
A simulation study on how to optimally storage products in a warehouse of a fashion supply chain selling through an e-commerce channel
by Eleonora Bottani, Letizia Tebaldi, Mariachiara Rossi, Giorgia Casella
Abstract: Where is it the most convenient to allocate a determined product? This paper, by means of a simulation tool, makes an attempt to answer this question, for the specific case of an e-commerce warehouse in which fashion items are stored. According to the typical steps of the Deming cycle, after having studied the current situation (AS IS scenario) of items allocation, a simulated one (TO BE scenario) was developed for studying a new allocation strategy, and for its assessment four key performance indicators (KPIs) were considered: the storage and picking productivity (both expressed in terms of processed units per hour), the percentage of FIFO batch for multi-customer orders and the time spent for batching (measured in hours). Results from the implementation show an improvement of the KPIs under investigation, as well as the observation of the specific targets set, and consequently an optimisation of picking activities
Keywords: warehouse optimisation; picking optimisation; PDCA; product allocation optimisation; logistics; e-commerce; fashion supply chain; simulation; case study.
An information-based model to assess human cognitive capacity and information processing speed of operators in Industry 4.0
by Daniela Cavallo, Salvatore Digiesi, Francesco Facchini, Giovanni Mummolo
Abstract: The fourth industrial revolution introduced a new paradigm in manufacturing systems. In the new production environments, operators are supported by new digital technologies, and the physical context is strictly related to the cyber one. In the digital society, recent studies show that individuals have to perform tasks based on the information gathered by a huge amount of data and the operators are employed in more cognitive than physical tasks. Therefore, the purpose of this paper consists in developing an information-based analytical framework to assess the human cognitive capacity occupancy and the human processing time of correct information when the quality performance is known. The model has been tested on case studies. The results show its effectiveness in evaluating the human mental workload imposed by the task performed and the processing speed of correct information with varying quality performance.
Keywords: cognitive task; mental workload; human information processing speed; smart operator; information theory model.
A numerical assessment of the influence of Industry 4.0 technologies on the cognitive complexity of procedure-guided tasks
by Francesco Facchini, Andrea Lucchese, Giorgio Mossa, Giovanni Mummolo, Francesco Paolo Sisto
Abstract: In the Industry 4.0 (I4.0) context, procedure-guided tasks are characterised by a greater complexity owing to the higher cognitive nature. On one side, increasing information processing demand and more articulated decision-making processes are required in new factories. On the other side, different I4.0 technologies are available to support workers in work environments. In this regard, the entropy measures were adopted to evaluate how the cognitive complexity required by general procedure-guided tasks changes when the I4.0 technologies are implemented. Results show that the implementation of I4.0 technologies decreases the information processing demand of the task (estimated in bit/s), reducing the cognitive effort of operators. Furthermore, the numerical simulation shows that adopting I4.0 technologies, an operator is able to perform a task 20% more complex (estimated in bit). Consequently, the study conducted allowed to predict how the information processing demand of procedure-guided tasks can be affected by implementing I4.0 technologies.
Keywords: cognitive complexity; task complexity; procedure-guided tasks; I4.0 technologies; Industry 4.0; entropy measure; task structure.
Digital clones and digital immunity: adversarial training handles both
by Vladyslav Branytskyi, Mariia Golovianko, Svitlana Gryshko, Diana Malyk, Vagan Terziyan, Tuure Tuunanen
Abstract: Smart manufacturing requires digital clones of physical objects (digital twins) and human decision-makers (cognitive clones). The latter requires use of machine learning to capture hidden personalised decision models from humans. Machine learning nowadays is a subject of various adversarial attacks (poisoning, evasion, etc.) on the training and testing data. Responsible use of machine learning requires some kind of 'digital immunity' (the capability of smart systems to operate robustly in adversarial conditions). Both problems (clones and immunity training) require the same backbone solution, which is adversarial training (learning on the basis of automatically generated adversarial samples). In this study, we designed and experimentally tested special algorithms for adversarial samples generation to fit simultaneously both purposes: to better personalise the decision models for digital clones and to train digital immunity to ensure robustness of the autonomous decision models. We demonstrated that our algorithms essentially facilitate the training process towards the desired robustness for both problems.
Keywords: digital cloning; digital immunity; Industry 4.0; adversarial machine learning; adversarial example generation; machine learning; generative adversarial networks; process modelling.
Special Issue on: I3M2020/ISM2020 Simulation and Process Modelling in Industry and Logistics New Advances in Theory, Methods and Applications
Systems of distributed artificial intelligence for analysis of oil product transportation processes: evidence from Russia
by Elena Serova, Daniil Shklyaev
Abstract: At present, the use of Artificial Intelligence (AI) methods and tools is an essential component of management information systems for a company to succeed in a rapidly changing environment. Agent-based modelling systems as systems of distributed AI must be considered nowadays as an obligatory stage of decision-making in Russian oil and gas companies, which use modern information technologies actively. The paper is focused on the description and comparative analysis of system dynamics and agent-based modelling, used for intelligent decision support systems development in transport logistics. The main goal of this research is evaluation of the multi-agent system's role for decision-making processes and management information systems development and creating the model of logistics processes (the processes of oil and oil products transportation, loading, and unloading). The work is based on a generalisation of theoretical researches in this area along with international practices and domestic experience.
Keywords: artificial intelligence; distributed artificial intelligence systems; simulation; agent-based modelling; transport logistics; processes of oil and oil products transportation.
Simulation-based cost optimisation of a risk mitigation strategy in an assembly job manufacturing process: a case study from the offshore wind industry
by Adolfo Lamas-Rodríguez, Javier Pernas-Álvarez, Inés Taracido-López, Santiago-José Tutor-Roca
Abstract: Despite holding very high expectations regarding installed capacity and planned investments, offshore wind energy is currently facing important challenges to align itself with the levelised cost of other renewable energies, such as solar power and onshore wind. In this context, we aim at putting DES optimisation at offshore winds disposal and leveraging its advantages proved in other areas. To accomplish this, we have performed a DES-based optimisation of the routing strategy and the net income of an offshore wind foundations manufacturing project affected by very important delays due to Covid-19 impact and material supply issues. The problem applies to a constraint-based multi-level assembly job shop where we use dispatching rules to model the routing decision. Overall, we have provided the company with an optimised schedule, due dates, expected penalties, expected net income and a detailed ongoing DES model to be used in further stages of the project.
Keywords: discrete-event simulation; simulation-based optimisation; offshore wind; Industry 4.0; dispatching rules; assembly job-shop; constraint-based simulation.
A fuzzy cognitive map based approach to prioritise environmental objectives in the environmental management systems of ports
by Maria Drakaki, Panagiotis Tzionas
Abstract: Increased attention is being paid to the environmental and social impacts of ports, adding pressure to the port authorities towards sustainable port management and development. Environmental priorities of European ports have changed over the years, however environmental aspects such as energy consumption, carbon footprint and waste are being monitored increasingly. A certified environmental management system (EMS) and definition of objectives and targets for monitoring environmental aspects are being used to assess the environmental management performance of ports. This paper proposes a modelling methodology based on Fuzzy Cognitive Maps (FCM) to prioritise environmental objectives and targets as part of an EMS for a port, and shows a case study for the port of Thessaloniki. The case study builds on the results of a previous study that employed the Ecological Footprint (EF) methodology to assess the CO2 emissions-related EF of the port of Thessaloniki for the time period 2008-2009.
Keywords: ports; fuzzy cognitive map; modelling; simulation scenarios; ecological footprint; environmental management systems; environmental objectives.
Discrete event simulation for the investment analysis of offshore wind manufacturing processes
by Adolfo Lamas-Rodríguez, Inés Taracido-López, Javier Pernas-Álvarez, Santiago-José Tutor-Roca
Abstract: Spreadsheets are by far the most widely employed tool to perform investment analysis. However, in operations research, their rigidness ignores the variability inherent in stochastic systems and neglects important factors that may affect the feasibility of the investment. Hence, we present here an innovative use of discrete event simulation for investment analysis by means of two case studies taken from the offshore wind industry. To do so, we implemented an algorithm on top of a 3D DES model, which performs the investment analysis in parallel with it. Results are shown by means of net present value and internal rate of return. In this way, we consider at once process variability and variable economic factors, such as discount rate, thus achieving more reliable results. Finally, we set investment parameters as target variables in the optimiser to obtain the best scenario regarding both productivity and profitability.
Keywords: investment analysis; discrete event simulation; optimisation; offshore wind; Industry 4.0; net present value; internal rate of return.
Discrete-event modelling of the capacity of the toll collection exit point and the formation of congestion
by Alexander Talavirya, Michael Laskin
Abstract: The study addresses the issue of assessing toll plaza (TP) throughput capacity and traffic congestion during toll road operations. To demonstrate a methodology for transport micro-modelling, the Western High Speed Diameter (WHSD) toll road TP in St. Petersburg, Russia, was used as a case study. The discrete-event simulation model of the TP at the toll road exit was developed using AnyLogic software. We accounted for the specifics of traffic composition and user behaviour in the selected urban district. The operation of the TP at low and high traffic flow rates was analysed using the developed simulation model. The empirical data parameters for service time distribution were obtained for each situation. When a TP operates above the threshold throughput capacity, a mathematical method for determining the parameters of the traffic congestion (queue length and time, number of vehicles in the queue) was proposed.
Keywords: discrete-event simulation; toll road; toll plaza; toll collection system; traffic congestion.
Robotic process automation and re-engineering Using Bizagi and UiPath: a case study on a mortgage request process
by Nouf Aljuhani, Fatimah Alshahrani, Amani Alharbi, Nuha Aldini, Hawazin Albalawi, Salma Elhag
Abstract: Recently, Robotic Process Automation (RPA) has become increasingly adopted by different institutions in an endeavour to improve business performance. However, banking and financial institutions are still considered a slow-developing sector lacking sufficient experience with different aspects of process automation. Therefore, the main aim of this work is to examine how RPA adoption can affect the performance of banking processes by conducting a case study on the mortgage loan application process of a bank located in Saudi Arabia. A well-established methodology inspired by the Business Process Management (BPM) lifecycle has been followed. We use the Bizagi (BPM) suite to model and analyse AS-IS and TO-BE scenarios of the process. UiPath software has been used to build and configure the RPA bot. The simulation results revealed that the adoption of the RPA within the mortgage loan application process has reduced the overall cycle time of the process by approximately 14 days.
Keywords: business process re-engineering; robotic process automation; banking processes; performance measures; simulation; RPA bot; mortgage loan process.
Society 5.0: a simulation optimisation study of dynamic scheduling for a grocery store
by Konstantinos Mykoniatis, Anastasia Angelopoulou, Samira Shirzaei
Abstract: Society 5.0 refers to a technology-based human-centred society that integrates cyber-physical systems and uses advanced technology to improve everyday life. Queuing systems, such as grocery stores, will transition to Society 5.0. Waiting time in the queue of such systems makes it difficult to determine the necessary number of resources to operate cost-effectively and keep customers satisfied. This work studies a grocery store with two types of resource: cashier-staffed billing counters and self-checkout machines. The objective of the study is to dynamically schedule the required number of resources such that the arriving customers experience reduced waiting times in the queue, while the store maintains low operational costs. The work uses the Simio simulation software and the OptQuest simulation optimisation engine to determine the staffing levels and achieve the aforementioned objectives. The optimisation experiment results showed that using dynamic resource scheduling can assist in maintaining satisfactory customer waiting times and operational costs.
Keywords: Society 5.0; discrete event simulation; queuing system; dynamic scheduling; optimization.
Human factors and entropy evaluation in collaborative workplace environment
by Sotirios Panagou, Fabio Fruggiero, Alfredo Lambiase
Abstract: The integration of advanced technologies, that the Industry 4.0 framework introduced, in the workplace environment requires from the human workforce to adapt to the workplace changes. A rising concern is the role of older workers and how smoothly can they integrate in workplace environments with automation and cobotics. To this extent, we introduce a statistical model based on entropy and human factor sustainability concept. The aim of the proposed model is to calculate the level of uncertainty inside a collaborative workplace, by computing the probability of error of human workforce, with the aid of the parameters and variables that governs the interactions between human operators and robotics cyber systems. This computational model was tested in a complex workplace framework by usage of advanced ICT technologies and tasks of increased complexity. Results show that the age factor play a role in the uncertainty inside the workplace.
Keywords: ageing; sustainability; human factors; entropy; workforce; capabilities; statistical; Industry 4.0; simulation; collaborative; workplace.
Dynamic characteristics and fatigue life analysis of key parts of ring die pellet mill
by Xin Li, Risu Na
Abstract: This paper establishes a drive system dynamic model of a ring die pellet mill, according to the working principle of the transmission system of the mill, Jeffcott rotor dynamics and mass concentration method. Modal analysis and numerical computation verified the accuracy of the dynamic model and key factors of the ring die pellet mill. In this study, random vibration analysis was performed based on the modal superposition by comparing the statistical tables of the failure data of the ring die pellet mill due to the short service life and severe wear of the ring die. In addition, combined with the material performance datebook, the Gaussian distribution and Miners linear damage accumulation law were used to predict the ring dies fatigue damage and fatigue life.
Keywords: ring die pellet mill; Jeffcott rotor dynamics; modal analysis; random vibration analysis.
Special Issue on: ISSPM2020 Advances in Simulation and Process Modelling
A methodology to characterise simulation models for discovery and composition: a system theory based approach to model curation for integration and reuse
by Bernard Zeigler
Abstract: We make a strong assumption that we can extract the necessary and sufficient information needed to decide whether a simulation model is suitable for an analyst's problem and that it contains information on how to be configured, integrated, and executed. This assumption allows us review an approach that is founded on the theory of modelling and simulation and employs tools to develop, simulate, and apply models expressed in the Discrete Event System Specification (DEVS) formalism, a sound systems theory-based computational methodology for system-of-systems model development and deployment. This foundation allows us to discuss how to apply the well-developed theory to curate simulation models so that they can more easily be discovered from a model repository given analytical objectives. After outlining the methodology, we place it in a broader context in which web- and cloud-based technologies are employed for integration and to enable modelling and simulation as a service. Significant technical challenges are described that require continued research and development.
Keywords: DEVS; theory of modelling and simulation; model curation; reusability; composability.
Simulation of pork supply chain based on system dynamics model
by Qianqian Shao, Xiaojing Zhang, Chong Li, Yang Liu
Abstract: In most of the advanced researches of pork supply chain (PSC) analysis, the systematic behaviour is only studied locally, and does not focus on the influence of different consumer demand changes on the system behaviour. In order to make the simulated PSC more authentic, different combinations of three demand types (random demand, sudden demand and cyclical demand) are considered in this model. Within the PSC, there is a causal relationship between the actions of enterprises. System dynamics (SD) can build complex system models to solve complex dynamic problems. Therefore, we analyse the PSC and integrate the system flow diagram and variable equations into a SD flowchart to study the internal behaviour. Taking Shenyang (China) PSC in 2020 as an example, the system behaviour was observed. In addition, the influence of price delay and transportation delay on pork price is further discussed.
Keywords: pork supply chain; system dynamic; pork price; flow diagram.
Simulation optimisation of displaced left-turn intersection layout with multi-objectives
by Qianqian Shao, Yingcheng Zheng, Yang Liu, Yan Xing
Abstract: The displaced left-turn (DLT) intersection, which effectively solve the conflict between left-turn and opposing-through traffic, is currently the most efficient innovative intersection design. However, the special layout of DLT will inevitably cause high difficulty in channelisation design. For full use of the potential traffic capacity of the DLT intersection, a multi-objective optimisation model for intersection with DLT layout (MOOM-DLTL) is built based on the integrated simulation and mathematical programming (ISMP) framework. In this model, the signal scheme is regarded as the accompanying strategy of DLT layout optimisation to describe the interaction between layout and signal control. In addition, the multi-objective particle swarm optimisation based on shift-based density estimation (MOPSO+SDE) algorithm is developed to obtain the Pareto front of the proposed model. A series of experimental results show that the proposed optimisation method is successful in improving the traffic efficiency of DLT intersection.
Keywords: displaced left-turn; multi-objective optimisation; layout design; MOPSO.
Effect of cap gap and welded seam strength on concrete-filled steel tube arch bridge ribs
by Zhengran Lu, Chao Guo
Abstract: In this paper, the quantitative analysis is investigated for the concrete-filled steel tube rib strength that contained defects. The friction Coulomb model was used to investigate the interaction between the steel tube and the concrete core. Based on the non-destructive testing data, the finite element analysis is simulated with ABAQUS to obtain the strength of serviced concrete-filled steel tube ribs containing cap gaps and reduced spiral-welded seam strength which are exposed to weak eccentric axial compression. The results show that spiral-welded seam defects have weaker influence on the bearing capacity of CFST than that on empty steel tube. However, it has a significant influence on CFST local yield failure mode. The cap gap defects have effect on the shape of N-? relationships. For CFSTs with composite defects, welded seam defects weakened local steel tube restrain capacity to concrete, resulting in CFST bending failure.
Keywords: composite defect; finite element method; concrete-filled steel tube; spiral welded seam; cap gap.