Construction Of Simulation Model Research Articles

A Compositional Approach to the Simulation of Queuing Systems with Random Parameters

A general approach to modeling random service processes under conditions of disturbances and uncertainty of the initial data is substantiated. A compositional approach to constructing simulation models of queuing with parametric uncertainty based on phase-type distributions and phase functions is proposed. The calculation and comparison of the characteristics of the developed simulation models with analytical solutions were carried out to confirm their effectiveness and accuracy. The problems of uncertainty of the initial data and their impact on the modeling of service systems are highlighted. The importance of taking into account parametric uncertainty in simulation models is emphasized in order to increase their adequacy and applicability in practice. The study includes a description of a general approach to modeling random service processes with uncertainty, as well as methodological foundations for the application of phase distributions and functions in compositional modeling. Four classes of service models are considered, differing in the type of integral core and phase function, which makes it possible to implement a variety of random service processes, taking into account their characteristics and conditions of their occurrence. The analysis of a model with an exponential integral core and various types of phase functions is carried out, which demonstrates the flexibility and wide possibilities of the proposed compositional approach to the study and modeling of service systems. The results of simulation modeling are presented, confirming analytical studies and showing the applicability and effectiveness of the developed approach in the construction and analysis of models of service systems with random parameters. The practical significance of the compositional method for the design and modernization of information and computing systems at various stages of their development, taking into account the uncertainty of the initial data, is noted. The work is focused on the development of simulation methods for queuing systems and opens up new prospects for their research and optimization in conditions of uncertainty of initial parameters.

Development and analysis of a traffic model in the AnyLogic environment

The Federal Work Program on Informatics for the 11th grade (advanced level) indicates the need to consider the issues of constructing simulation models, provides the practical works on motion modeling and processing of experimental results. Development and analysis of simulation models related to road traffic management is interesting and understandable for schoolchildren. These models can be implemented in the AnyLogic environment, for which it is advisable to offer schoolchildren to create a model of an intersection they are familiar with and analyze at what traffic intensity there is no need to install a traffic light, when a traffic light is necessary, what time phases of the traffic light provide the highest capacity of the intersection. The article describes algorithms for creating models of unregulated and regulated intersections; presents tasks for analyzing the capacity of the intersection for different values of the number of cars in each direction of traffic per hour; describes tasks for optimizing the phases of the traffic light to increase the capacity of the intersection; provides examples of project topics for organizing independent work of students.

Investigation of Dynamic Characteristics of Holonomic Robot with Mecanum wheels Based on 3D Parametric Simulation Model

The paper analyzes dynamic characteristics of a four-wheeled mobile robot driven by omnidirectional mecanum wheels. To obtain information about dynamic characteristics of the robot, a computer model was developed in the MATLAB Simulink block modeling software environment. The constructed simulation model allowed to research the behavior of a holonomic mobile object with mecanum wheels in start-braking modes, based not only on its mathematical model, but also ta-king into account the weight and size parameters of the robot, introduced into the model through the integration of a three-dimensional digital prototype of the object. The investigation of the omnidirectional robot dynamics was considered within modeling the acceleration, uniform movement and deceleration of an object on a plane along a rectilinear trajectory. As a result, the dependences of kinematic, dynamic and mechanical characteristics were obtained, such as the dependence of angular velocity and torque of each wheel on time; the dependence of linear velocity of the robot's center of mass on time; the dependence of distance traveled by the robot on time; positioning errors while processing a given movement; spatial visualization of speed fluctuations. With the help of Mechanical Explorer tool, using a digital clone of the robot integrated into the model, an animation of the object’s movement along the trajectory was obtained. This approach, based on the integration of mathematical block and three-dimensional parametric models of the object with the possibility of visualization and animation of the results, allows to most fully investigate the dynamics and kinematics of nonlinear mechatronic systems. The obtained information of positioning errors and speed fluctuations in three coordinates allowed to conclude that there were random fluctuations during the robot’s movement, but their presence did not have a noticeable effect on the accuracy of the specified trajectory.

Simplification and simulation of evaluation process for low efficiency constructed wetlands based on principal component analysis and machine learning

The existing performance evaluation process of constructed wetlands (CWs) is complex, with shortcomings in both simplification of method and construction of simulation model, especially for low-efficiency CWs (LECWs, with an average close-degree calculated by the entropy weight method being <0.6). This study presents a case study of LECWs in the Ningxia region (comprising 13 subsurface flow constructed wetlands (SSF CWs) and 7 surface flow constructed wetlands (SF CWs)), employs the entropy weight method (EWM) to construct an evaluation of CW operational efficiency, simplifies evaluation indicators through principal component analysis (PCA), develops two random forest (RF) models to validate the rationality of the simplified indicators, and establishes simulation models by logistic regression (LR). The results demonstrate that the evaluation indicators of CWs can be simplified to chemical oxygen demand (COD) and total nitrogen (TN), with no significant difference observed between the evaluation results and the original model (P < 0.05), thereby indicating reliability. Moreover, the simulation model performs well with R2 values for fitting SSF CWs and SF CWs exceeding 0.8. According to the simulated results of the model, the operational efficiency of LECWs is more significantly affected by the COD removal rates compared to the TN removal rates. In comparison to influent with 0 < COD/TN < 3 and 5 < COD/TN < 8, the operational efficiency of SSF CWs and SF CWs is optimal when COD/TN is between 3 and 5. These research findings may provide valuable support for streamlining evaluation processes and daily management for LECWs.

Research on the characteristics of a pneumatic proportional valve

Abstract The execution of autonomous driving in heavy-duty trucks necessitates stringent regulation of their braking torque output. Hydraulic retarder serves as a widely auxiliary braking system in heavy-duty vehicles, with the pneumatic proportional valve functioning as the core component of its control system, regulating the output response and control precision of the braking torque of the hydraulic retarder. To improve the accuracy of brake torque control for hydraulic retarders, it is critical to conduct thorough research on the control system, especially the pneumatic proportional valve. Therefore, A detailed analysis of the working mechanism of pneumatic proportional valves was conducted, encompassing the construction of mathematical and simulation models. The efficacy of the simulation model was confirmed via experimental validation. When the control pressure increases, the simulation results are close to the experimental results, with a maximum discrepancy of 18%; when the control pressure decreases, the simulation results show a similar trend to the experimental results. The research can aid in formulating control methodologies for pneumatic proportional valves and offer theoretical guidelines for future exploration into boosting the precision of hydraulic retarder braking torque control.

Intelligent Technology for Construction of Dynamic Integrated Expert Systems: Specificities of Construction of Simulation Models of the External Environment

Intelligent Technology for Construction of Dynamic Integrated Expert Systems: Specificities of Construction of Simulation Models of the External Environment

Construction and Characteristic Analysis of Dynamic Stress Coupling Simulation Models for the Attitude-Adjustable Chassis of a Combine Harvester

Construction and Characteristic Analysis of Dynamic Stress Coupling Simulation Models for the Attitude-Adjustable Chassis of a Combine Harvester

Study on the Erosion Resistance of Different TiN Crystal Planes by Molecular Dynamics.

In this study, we innovatively combined the Fe-Ti-N potential function file to construct simulation models of different crystal facets of TiN/Fe ((001), (110), and (111)), which had not been previously explored. Employing molecular dynamics (MD) simulations, the research investigates the microscale differences in erosion resistance and surface properties of various TiN crystal planes under continuous impacts at varying velocities and angles. The results indicate that both surface wear and internal defects of the model increase with the impact velocity. Both TiN(110) and TiN(111) exhibit damage on their surfaces and interiors, with a larger wear range. In contrast, TiN(001), due to its superior elastic recovery capability, maintains a better surface condition, showing significantly less wear compared to TiN(110) and TiN(111). This disparity in performance among different crystal planes is attributed to variations in molecular gaps between planes, bonding points within the lattice, types of forces, and modes of action. Further research revealed that the wear volume increased with the rise in impact angle, reaching its peak at 90°. Regardless of the impact angle, TiN(001) consistently outperformed TiN(110) and TiN(111). The aim of the research is to compare the surface and internal defects of different crystal facets at the microscopic level, thereby selecting superior crystal facets and providing theoretical reference for the application of TiN materials in practical fracturing environments.

Research on engine dynamic torque modeling for torsional vibration analysis of vehicle powertrain

In order to improve the accuracy of dynamic torque model of engine, a simulation model of quasi-transient engine dynamic torque under all operating conditions was established considering the influence of throttle opening. Firstly, the calculation model of engine output torque and cylinder pressure is established according to the kinematic relation of crank linkage mechanism. Secondly, BP neural network is used to establish the mapping relationship model of throttle opening, rotational speed, and cylinder pressure ratio data. In order to solve the contradiction between calculation accuracy and efficiency of engine cylinder pressure interpolation, a quadratic interpolation method is proposed, which refines data to improve interpolation accuracy, and improves calculation efficiency by online adjacent interpolation, and completes the construction of dynamic torque simulation model of engine in all working conditions. Finally, the experimental data of dynamic torque characteristics of the engine at different speeds are used to verify the accuracy of the model calculation. By using the verified engine model, the dynamic operating characteristics of variable valve opening and variable speed are simulated and analyzed. The results show that the model established in this paper can effectively reflect the dynamic characteristics of the engine, and the model is suitable for the simulation of the torsional vibration of the vehicle powertrain under steady and unsteady conditions.

Optimal Cooling System Layout Identification for EV Components

As the automotive sector transitions to electrification, it presents a significant technological challenge in meeting consumers' demands for reduced energy use while maintaining vehicle performance. In the early stages of developing concepts and system performance in a specific operating environment, it is critical to construct simulation models to accelerate the development process while keeping costs to a minimum. In this study, a novel framework is proposed to enable an automated optimal cooling system layout. The methodology starts with a set of components, design rules, and system requirements to automatically generate all the admissible cooling system layouts. System layouts are generated by a concept based on a yoke chain tree. The generated layouts are coupled to a set of design rules based on the hydraulic and thermal requirements of the cooling system. Each layout is iteratively simulated based on rules in the available solution space to explore the Optimal ones. The case of the Powertrain Circuit in the electric vehicle cooling system was taken as the reference for this study. The best candidates are identified by a two-criteria optimization problem based on maximizing efficiency and minimizing the power consumption of the system. Results indicate that the difference in energy consumption between the best-performing layout and the worst one is 169%. Keywords: EV, Cooling System, Modelling, Simulations, Optimization, Cooling System Layouts

Selecting a priority criterion when forming optimal management of a production enterprise using digitalization tools

Relevance. At the present stage, economic and mathematical methods cannot be fully implemented without the use of digitalization tools. The center of many modern theoretical studies, both by foreign and Russian authors, is a simulation model that allows the most complete reflection of both the theoretical message under consideration and its nuances, to which a software package or modeling tools can be fully adapted. The activities of various production and technology companies may be influenced by external factors, which must be resolved not only strategically, but also operationally. Methodological problems lie in the choice of a priority criterion for the formation of optimal management of a manufacturing enterprise using digitalization tools.The purpose is to select a priority criterion for the formation of optimal management of a manufacturing enterprise using digitalization tools.Objectives. objective prerequisites for the construction of simulation models based on an optimization approach are given; the initial formulation of the convex programming problem is justified, an analysis of the priority of weight coefficients is given; the accuracy of calculation and the type of utility function is justified when the analysis of the prevailing normalized prices is assumed. In such initial conditions, the solution of the convex programming problem can be reduced to finding the optimum in the production planning problem.Methodology. The study was carried out using methods of logical and comparative analysis of existing simulation models of operational management of the company, as well as methods of mathematical modeling.Results. The paper proposes an algorithm for the phased implementation of the optimization task, taking into account three relevant responses of the system to the use of resource-saving technologies, determined by the use of a specific type of technological production.Conclusions. The priority of choosing a criterion in the formation of optimal management of a manufacturing enterprise using digitalization tools creates favorable conditions for the system's response to technology changes, depending on three possible states of production technology: ultra-efficient technology, extremely backward technology, medium or normal technology.

Passive Super-Twisting Second-Order Sliding Mode Control Strategy for Input Stage of MMC-PET

When the operating state of the power system changes, a modular multilevel converter power electronic transformer (MMC-PET) based on modular multilevel converters cannot perform efficient energy transfer and power conversion under conventional control strategies. To address the above problems, this paper proposes a passive, second-order super-helical sliding mode control strategy for MMC-PET by combining passive control and second-order super-helical sliding mode control with a stronger anti-interference capability. First, a Euler–Lagrange model based on positive and negative sequence separation is established according to the mathematical model of the MMC; second, the model of the system is passively analyzed, and a passive controller is designed according to its passivity, and the passive controller is further optimized by using the super-helical second-order sliding mode control, which improves the overall robustness and interference immunity; finally, the effectiveness and superiority of the super-twisting second-order sliding mode passive control strategy is demonstrated by verifying it through the construction of the MMC-PET simulation model and testing it under various non-ideal working conditions.

Simulation model of tumor-treating fields

Tumor-treating fields (TTFields) is a novel treatment modality for malignant solid tumors, often employing electric field simulations to analyze the distribution of electric fields on the tumor under different parameters of TTFields. Due to the present difficulties and high costs associated with reproducing or implementing the simulation model construction techniques, this study used readily available open-source software tools to construct a highly accurate, easily implementable finite element simulation model for TTFields. The accuracy of the model is at a level of 1 mm 3. Using this simulation model, the study carried out analyses of different factors, such as tissue electrical parameters and electrode configurations. The results show that factors influncing the distribution of the internal electric field of the tumor include changes in scalp and skull conductivity (with a maximum variation of 21.0% in the treatment field of the tumor), changes in tumor conductivity (with a maximum variation of 157.8% in the treatment field of the tumor), and different electrode positions and combinations (with a maximum variation of 74.2% in the treatment field of the tumor). In summary, the results of this study validate the feasibility and effectiveness of the proposed modeling method, which can provide an important reference for future simulation analyses of TTFields and clinical applications.

Adaptive coordinated control strategy for improving shift quality under different operating conditions

In order to improve the shift quality of vehicles under different operating conditions (such as road resistance coefficient and throttle opening), this paper proposes an adaptive coordinated control strategy. This strategy utilizes a Forgetting Factor Recursive Least Squares (FFRLS) to achieve online identification of the road resistance coefficient. Based on the changes in throttle pedal opening and road resistance coefficient during the vehicle’s shifting process, the strategy adaptively adjusts the coordinated control parameter (fuel cut-off time) to achieve optimal control of vehicle shifting under different operating conditions. To evaluate the shift quality, shift jerk, friction work, torque peak, and shift time are used as performance indicators. Based on a constructed simulation model of the powertrain system, the influence of different operating conditions on the performance indicators is analyzed, and the effect of coordinated control parameters on improving shift quality under different operating conditions is compared. Corresponding fuzzy rules are then established to achieve adaptive adjustment of the coordinated control parameters through fuzzy control, ensuring effective improvement of shift quality for vehicles under different operating conditions.

Simulation Model Construction of Plant Height and Leaf Area Index Based on the Overground Weight of Greenhouse Tomato: Device Development and Application

Plant height and leaf area index (LAI) are crucial growth indicators that reflect the growth status of tomatoes in greenhouses, enabling accurate determinations to effectively estimate crop transpiration and formulate irrigation strategies for reducing agricultural water waste. There is a need for the increased application of related models to simulate tomato growth indices in the traditional greenhouse production in China. This study proposes a nondestructive, real-time monitoring and simulation device for measuring tomato plant height and leaf area index. The weight of aboveground tomatoes was obtained by suspending tomato plants on dynamometers, while the total weight of stem and leaf organs was determined using a distribution coefficient simulation model. The R2 value between the measurements from the electronic scale and those from the aboveground fresh weight device for tomatoes was 0.937, with an RMSE value of 0.05 kg. The monitoring device did not affect the average tomato growth during operation. The device will not affect the growth of tomatoes during monitoring. A multiple linear regression was used to compare the measured and simulated values of the plant height and leaf area index of various types of greenhouse tomatoes cultivated in different greenhouse types. The average R2 value for simulating plant height was 0.817 with an RMSE of 10.81 cm. The average R2 value for the leaf area index was 0.854, with an RMSE of 0.55 m2·m−2. The simulated values for plant height and leaf area index closely matched the measured values, indicating that the model has high accuracy and applicability in traditional Chinese greenhouses (solar greenhouses and insulated plastic greenhouses). However, further optimization is required for commercially produced, continuous plastic greenhouses equipped with greenhouse environmental control equipment.

SIMULATION MODELING OF MULTIPLE PREEMPTIONS OF BARGES AND CRANES UNLOADING FILL FOR LAND RECLAMATION

In construction simulation modeling, preemption is the interruption of activities in progress and the reallocation of their resources to other activities when triggering events occur, such as when geologic conditions change, or equipment fails. Modeling activity preemption correctly, however, is not trivial and requires specialized modeling elements such as those added to the STROBOSCOPE simulation system. These new preemption STROBOSCOPE functions and statements are first described and then applied to an example project where barges bring fill material for land reclamation to a harbor that has two berths and two cranes. When two barges are at the berths, each barge is unloaded by one crane. When only one barge is available, it is unloaded by both cranes working together and the remainder of its unloading time is halved. When a new barge arrives at the empty berth, the two cranes switch back to unloading one barge each, and the remaining unloading time for the first barge is doubled. The unloading of each barge can switch between using one and two cranes multiple times, with its remaining time to finish unloading either cut in half or doubled each time. The multiple activity preemptions caused by the changes in the number of cranes unloading each barge and the required adjustments in the barge’s remaining time to unload illustrate the challenging nature of activity preemption and the new STROBOSCOPE modeling capabilities.

HEAVY CONSTRUCTION EARTHMOVING SIMULATION USING ENGINEERING CALCULATIONS

Earthmoving for major civil engineering heavy construction works, such as dams, levees, or highways, has been a typical application area for construction simulation models. Missing from these models are the engineering calculations typically performed by heavy construction contractors based on the length, grade, and rolling resistance of the haul and return roads and the actual mechanical characteristics of the trucks that will haul the material. Detailed STROBOSCOPE simulations illustrate how to model the performance of heavy construction equipment by using engineering calculations as is usually performed in practice. Earthmoving for the construction of a dam illustrates how to model the loading and hauling of material based on the characteristics of the haul and return roads and the mechanical properties of actual models of loaders and trucks, such as bucket size, engine power, transmission efficiency, retarding power, etc. Sensitivity analysis investigates the total cost of truck combinations while considering the traffic effects of one or two bridges needed to cross a river along the haul route. This example can serve as a simulation model template to facilitate the wider acceptance of simulation in heavy construction practice.

An Assortment–Quantity Optimization Problem in Printing Industry Using Simulation Modelling

This paper presents a method for assortment–quantity production scheduling in a printing company. The company uses specialized machinery to make prints on clothing. The method is based on a study of the company’s practical operations and the production technologies used. It involves the construction of simulation and optimization models of the process. The simulation models reflect the technical aspects of the production process and the business requirements. Optimization models provide solutions that balance product sales revenue with appropriate production schedules. On this basis, managers can make resource-balanced decisions on the implementation of selected production plans, taking into account the current economic conditions of the company. The experiments used the FlexSim simulation program (by FlexSim Software Products, Inc., Orem, UT 84097 USA; v. 20.1.3.1) and the OptQuest optimization package (embedded in FlexSim), resulting in a cost-effective solution in a short time. The proposed method, thanks to the optimization of the production program, provides savings in the use of materials for production, as well as water and energy savings in the production process. Thanks to the possibility of analyzing the process without interfering with it, provided by simulation modelling, the method practically eliminates the costs and time needed to prepare the execution of new production orders. This contributes to the sustainable development of the company and provides an opportunity to assess the impact of potential business decisions in the company prior to their implementation. The method has been directly applied in a company to improve its performance. The method is scalable and can be applied to problems of varying complexity and production systems of different types and sizes. This is especially true for small- and medium-sized companies that use discrete manufacturing in the textile, metal, and furniture industries.

Retracted: Construction and Research of Guqin Sound Synthesis and Plucking Big Data Simulation Model Based on Computer Synthesis Technology

Retracted: Construction and Research of Guqin Sound Synthesis and Plucking Big Data Simulation Model Based on Computer Synthesis Technology

Simulation Modeling of QS with Hyper-Erlang and Erlang Distributions

The article is devoted to the construction of simulation models of customer delay in the queue in the form of a queuing system (QS) described by both ordinary and right-shifted hyper-Erlang and second-order Erlang distributions. This article is a logical continuation of previous works devoted to the construction of numerical-analytical QS models with shifted distribution laws. In the article, the Erlang distribution is considered as a special case of the more general Gamma distribution law, in contrast to the normalized Erlang distribution. These two forms of the Erlang distribution differ in numerical characteristics, except for the coefficient of variation. To solve the problem, the system of discrete-event modeling GPSS WORLD was used.