scholarly journals Application of computer agent modeling for optimization of the assembly process

Author(s):  
І.О. Ушакова

Computer modeling is a method for solving the problems of analysis or synthesis of a complex system based on the use of its computer model. Simulation, as a component of computer modeling, allows you to construct most of the possible states of the analyzed system. In this way it allows to correct the processes of assembling machines in a minimum time and with minimal costs, to foresee possible risks and to avoid unreasonable decisions regarding the organization of processes, to reduce material costs. Simulation gives the best results for modeling uncertain or probabilistic systems. Simulation, as a component of computer modeling, gives the best results for modeling systems with uncertainty or with a probabilistic nature. Mathematically calculating all possible variants of the system’s behavior is a laborious task, and using average values in the calculations gives inaccurate results. For assembly production systems, simulation modeling is used to select the optimal production organization parameters. The aim of this work is to build a computer simulation model that allows you to evaluate the impact of production factors (number of employees, operating parameters and type of assembly process) on the assembly process and substantiate the effectiveness of the model. The current assembly process of the machine was considered for modeling. The assembly process includes: two streams of verification, synchronization of request from these two streams, and a machine collection stream. The vacated line starts servicing the application that entered the system earlier than others. Such a discipline is called “earlier entered - earlier served” (FIFO - First In - First Out).s from flows, and a machine assembly flow. An optimization experiment was carried out after the construction and verification of the simulation model. The maximum value of profit was chosen as the objective function. Iterations were performed during an optimization experiment. The optimal number of employees was selected for two inspection flows and a machine assembly stream in the assembly shop. The first experimental result showed the effectiveness of the request flow synchronization method. The following optimization experiment showed the relationship between the number of workers in certain threads of the assembly process and profit. The results of using agent-based models for simulation can be used to optimize assembly processes.

2018 ◽  
Vol 12 (2) ◽  
pp. 129-133 ◽  
Author(s):  
Daniel Chalk ◽  
Neil Trent ◽  
Sarath Vennam ◽  
John McGrane ◽  
Mark Mantle

Objective: To develop a simulation model to identify key bottlenecks in the bladder cancer pathway at Royal Cornwall Hospital and predict the impact of potential changes to reduce these delays. Materials and methods: The diagnosis and treatment of muscle-invasive bladder cancer can suffer numerous delays, which can significantly affect patient outcomes. We developed a discrete event computer simulation model of the flow of patients through the bladder cancer pathway at the hospital, using anonymised patient records from 2014 and 2015. The changes tested in the model were for patients suspected to have muscle-invasive disease on flexible cystoscopy. Those patients were ‘fast-tracked’ to receive their transurethral resection of bladder tumour (TURBT) treatment using operating slots kept free for these patients. A staging computed tomography scan was booked in the haematuria clinic. Pathology requests were marked as 48 hour turnaround. The nurse specialist would then speak to the patient whilst they were on the ward following their TURBT to give information about their ongoing treatment and provide support. Results: The model predicted that if the changes were implemented, delays in the system could be reduced by around 5 weeks. The changes were implemented, and analysis of 3 months of the data post-implementation shows that the average time in the system was reduced by 5 weeks. The environment created by the changes in the pathway improved referral to treatment times in both muscle-invasive and non-muscle-invasive groups. Conclusion: The simulation model proved an invaluable tool for facilitating the implementation of changes. Simple changes to the pathway led to significant reductions in delays for bladder cancer patients at Royal Cornwall Hospital. Level of evidence: Not applicable for this cohort study.


Soil Research ◽  
1992 ◽  
Vol 30 (5) ◽  
pp. 757 ◽  
Author(s):  
M Littleboy ◽  
DM Silburn ◽  
DM Freebairn ◽  
DR Woodruff ◽  
GL Hammer ◽  
...  

A computer simulation model to analyse risks of soil erosion to long-term crop production is described. The model, called PERFECT, simulates interactions between soil type, climate, fallow management strategy and crop sequence. It contains six main modules; data input, water balance, crop growth, crop residue, erosion and model output. Modules are arranged in a framework that allows alternative modules to be used as required for the potential range of applications. The model contains dynamic crop growth models for wheat, sorghum and sunflower. Validation of PERFECT against small catchment and contour bay data collected throughout Queensland showed that PERFECT explained up to 84% of the variation in total available soil water, 89% of the variation in daily runoff, and up to 75% of the variation in grain yield. Average annual soil erosion was accurately predicted but daily erosion totals were less accurate due to the exclusion of rainfall intensity in erosion prediction. Variability in climate dominates agricultural production in the subtropical region of Australia. The validated model can be coupled with long-term climate and soils databases to simulate probabilities of production and erosion risks due to climatic variability. It provides a method to determine the impact of soil erosion on long-term productivity.


2014 ◽  
Vol 609-610 ◽  
pp. 1343-1348
Author(s):  
He Zhang ◽  
Xiao Wei Liu ◽  
Li Tian ◽  
Xiao Wei Han

In this paper, we focused the mixed results of the micromixer with the same quantity of electrodes but different placement. We imposed time dependent electric potential on different electrodes under the low Reynolds number condition, and then evaluated the impact of electrode position to the mixed results and summarized some rules which were conducive to achieving mixed. According to the simulation results and combined with the assembly process, we obtained the optimal number and placement of microelectrodes.


2014 ◽  
Vol 643 ◽  
pp. 42-47 ◽  
Author(s):  
Yan Xiao Fu ◽  
Liang Yi Cui ◽  
Xiang Yang Xu ◽  
Peng Dong

Basing on the fact that requirements for shift quality in automatic transmissions have been increasing rapidly necessitates the establishment of a suitable shifting control strategy in order to facilitate smoothness of different processes, this paper introduces a simulation model of an 8-speed automatic transmission for front-drive vehicles with respect to detailed shifting strategies and relative parameters. The transmitted torque of the oncoming shift elements before synchronization point can be reduced by an impact function in order to damp the impact and thus make the gear shifting process more smooth. This paper makes a systematic introduction of the structure of 8AT, theoretical basis of control strategy, the establishment of the simulation model and the comparison between test results and simulation results. The conclusion shows that with an accurate dynamic model, simulation results and test results are neighborhood data, the simulation model can be used to help realizing the ultimate goal of better shift quality with higher efficiency, lower shift loads and improved shifting comfort.


BMJ Open ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. e045577
Author(s):  
Katherine Robertson ◽  
Ian Hardingham ◽  
Rhiannon D'Arcy ◽  
Aparna Reddy ◽  
Joe Clacey

ObjectivesDelay in the induction of labour (IOL) process is associated with poor patient experience and adverse perinatal outcome. Our objective was to identify factors associated with delay in the IOL process and develop interventions to reduce delay.Design and settingsWe performed a retrospective cohort study of maternity unit workload in a large UK district general hospital. Electronic hospital records were used to quantify delay in the IOL process and linear regression analysis was performed to assess significant associations between delay and potential causative factors. A novel computer maternity unit simulation model, MUMSIM (Maternity Unit Management SIMulation), was developed using real-world data and interventions were tested to identify those associated with a reduction in delay.ParticipantsAll women giving birth at Stoke Mandeville Hospital, Buckinghamshire National Health Service (NHS) Trust in 2018 (n=4932).Primary outcome measureDelay in the IOL process of more than 12 hours.ResultsThe retrospective analysis of real-world maternity unit workload showed 30% of women had IOL and of these, 33% were delayed >12 hours with 20% delayed >24 hours, 10% delayed >48 hours and 1.3% delayed >72 hours. Delay was significantly associated with the total number of labouring women (p=0.008) and the number of booked IOL (p=0.009) but not emergency IOL, spontaneously labouring women or staffing shortfall. The MUMSIM computer simulation predicted that changing from slow release 24-hour prostaglandin to 6-hour prostaglandin for primiparous women would reduce delay by 4% (p<0.0001) and that additional staffing interventions could significantly reduce delay up to 17.9% (p<0.0001).ConclusionsPlanned obstetric workload of booked IOL is associated with delay rather than the unpredictable workload of women in spontaneous labour or emergency IOL. We present a novel maternity unit computer simulation model, MUMSIM, which allows prediction of the impact of interventions to reduce delay.


2014 ◽  
Vol 32 (30_suppl) ◽  
pp. 132-132
Author(s):  
Ranganath K. Iyer ◽  
Joseph Rodgers Steele ◽  
Habib Tannir ◽  
Steve Venable

132 Background: Patients scheduled to undergo computed tomography (CT) should be treated expeditiously and not delayed owing to a lack of either CT scanner capacity or available staff. Delayed scanning affects both patients and staff in several ways. First, patients are unhappy that they have to wait. Also, delayed scanning makes patient late for their next appointments or other events, which affects the downstream departments’ capability to operate effectively and efficiently. In addition, radiologists and their staff have to commit additional time and resources to processing patients on time. Finally, variability in the placement of patients reduces the scanner’s operating efficiency. The aim of this initiative is to optimize the appointment template using simulation software to reduce the rate of delayed CT procedures by 25% or more by the end of 2014. Methods: To further understand the CT queuing process, we hired 2 graduate students to create a simulation model using the data collected from the operations study. The simulation study modeled patients’ experience from their arrival to discharge and the steps were: (a) performed elemental analysis for each process; (b) cceated value stream map; (c) created high-level simulation model and “mini model” using operational data. The simulation models were presented to department leaders, who approved them. The models clearly showed that the time patients spent on the CT scanner was the bottleneck. Results: Changes in the CT area that have impacted on-time starts and average wait time include: (a) new fast-track for no interview patients and (b) changes in staffing hours. Progress and improvement include (a.) On-time delays decreased by 18% and (b.) a verage wait decreased by 8 minutes (19%). Conclusions: Discrete event simulation accounts for the probabilities and uncertainties associated with the processes and helps create a visual model of the work area. This adds confidence to decision makers’ ability to make decisions that have high impact. Also, the models can be used to test changes in the processes and study the impact on other processes without making true operational changes that could potentially waste resources and time.


1977 ◽  
Vol 34 (12) ◽  
pp. 2295-2307 ◽  
Author(s):  
Nicholas C. Sonntag ◽  
Wulf Greve

A computer simulation model of a phytoplankton–zooplankton–salmon system is used to investigate possible causes of different Pseudocalanus minutus s.l. population dynamics in three enclosed water columns. Mercury at 1 and 5 μg/ℓ was added to two enclosures, with the third serving as a control. Represented in the model are diatoms, flagellates, P. minutus, and fingerling chum salmon (Oncorhynchus keta). Population dynamics are represented in terms of age structure, with age-dependent feeding and survival. Real world data are used to represent the phytoplankton densities. The model results support a hypothesis that the observed Pseudocalanus populations after day 25 could have been a direct consequence of different flagellate populations in the enclosures rather than lethal effects of mercury on molting and reproduction success of the copepod. Key words: modeling, simulation, controlled ecosystems, mercury, zooplankton dynamics


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Lukas Jud ◽  
Lazaros Vlachopoulos ◽  
Thomas V. Häller ◽  
Sandro F. Fucentese ◽  
Stefan Rahm ◽  
...  

2019 ◽  
Vol 132 ◽  
pp. 01012
Author(s):  
Maciej Kuboń ◽  
Ireneusz Kaczmar ◽  
Pavol Findura

The paper focuses on computer modeling of the reliability of technical systems using FlexSim simulation software. It presents the theoretical foundations of machine reliability and principles of describing this phenomenon. The discussion demonstrates how to estimate the main parameters of reliability analysis - MTBF and MTTR. The end result was designing a simulation model and assessing the impact of machine failure on the productivity and performance of a technical system.


Author(s):  
Q. John Zhang ◽  
Jerry Rescigno

Abstract This paper studied the transient response of a single reduction gear train under a pulsating torque. A 4-DOF model has been used to estimate the impact load on the gear teeth. The system equations are solved under different gear backlash, inertia, stiffness and gear ratio conditions. The sensitivities of impact load versus these parameters have been summarized. The nonlinear behavior of the impact force changing from period to random due to the torque drop is investigated. Angular velocity test verified the power input curve. Angular acceleration and lock-rotor tests show the agreement between the model simulation and experimental result.


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