International Journal for Engineering Modelling
International Journal for Engineering Modelling is an open-access online journal that publishes original scientific papers, preliminary communications, subject reviews, and professional papers in all areas of biotechnology in biomedicine, interdisciplinary technical sciences, mechanical engineering, computing, civil engineering, electrical engineering, shipbuilding, and technical sciences. The topics covered in the Journal include computer-aided analysis, design, and research in the fields of computational mechanics, numerical methods, software development, and engineering modelling. The Journal is a double-blind peer-reviewed journal that does not charge either article processing charges (APCs) or article submission charges. Papers are published in English, with two issues per year. All content is immediately and freely available to anyone, anywhere. Users are allowed to read, download, copy, redistribute, print, search, and link to material, and alter, transform, or build upon the material, or use them for any other lawful purpose as long as they appropriately attribute the source according to the CC BY license Creative Commons Attribution 4.0 International License. Papers published in the International Journal for Engineering Modelling can be deposited and self-archived in institutional and thematic repositories, provided the link to the journal's web pages and HRČAK is included. The journal content is archived with a long-term preservation service of the National and University Library in Zagreb. This Journal is supported by the Ministry of Science and Education and Youth of the Republic of Croatia and the University of Split.
Faculty of Civil Engineering, Architecture and Geodesy ; Faculty of Electrical Engineering, Mechanical Engineering and Naval Architecture Matice hrvatske 15, 21000 Split (FGAG)
Analysis of Stress Intensity Factor in a Cracked Plate
The present paper aimed to study the effect of the hole on the stress distribution and stress intensity factor of the mode I fracture in a perforated plate with an edge crack. For this purpose, a plate with an edge crack and one or two holes near the crack tip is investigated. First, the cracked plate without a hole was analysed with Abaqus software, and the results were validated through Westergaard’s analytical method. Then, a plate with an edge crack and one or two holes near the crack tip was also analysed with Abaqus software. The effects of the distance between the hole and the crack tip, as well as the radii of the holes on the stress distribution σy and stress intensity factor KI were also investigated. The findings indicated that making a hole in the plate significantly reduces the amounts of the stress and stress intensity factor at the crack tip if the hole has an appropriate radius and position relative to the crack tip.
stress intensity factor; edge crack; finite element method; perforated plate; stress distribution
Copyright (c) 2026 https://creativecommons.org/licenses/by/4.0
Performance of Multiscale Hydrodynamic Step Bearing with Inhomogeneous Surfaces
In the hydrodynamic step bearing, when the lubricating film thickness is as low as the adsorbed layer thickness on the surface, the adsorbed layer effect on the bearing pressure should be evident. Different interactions can be formed between the fluid and the static surface in the bearing inlet and outlet zones, respectively. In this paper, the multiscale calculation was made for the pressures generated in this type of step bearing when the continuum film exists between the adsorbed layers. The calculation outcomes show that the hydrodynamic pressures and loads of the bearing for the S(strong)-M(medium)-S(strong) and S(strong)-W(weak)-S(strong) fluid-bearing surface interaction types exceed significantly those for the S(strong)-S(strong)-S(strong) fluid-bearing surface interaction type if the bearing clearance in the outlet zone is smaller than 100nm (and over 20nm). The results indicate that for higher hydrodynamic pressures in the bearing, the interaction between the fluid and the static surface in the outlet zone is stronger than that in the inlet zone.
adsorbed layer; hydrodynamic pressure; hydrodynamic bearing; inhomogeneous surface; load-carrying capacity; multiscale
Vibratory Conveying by Normal Oscillations with Piecewise Constant Acceleration and Longitudinal Harmonic Oscillations
Vibratory conveying of a material point by harmonic longitudinal oscillations and normal oscillations with a piecewise constant acceleration of an inclined conveying surface is considered. The dependence of dimensionless conveying velocity (a ratio of velocity to the product of frequency and amplitude of longitudinal oscillations) on several dimensionless parameters is investigated in the moving modes without hopping. Maximal conveying velocity is achieved at a certain value of phase difference angle between the longitudinal and normal oscillations, which is called optimal. The equations for determining the optimal phase difference angle are obtained. The values of dimensionless conveying velocity and optimal phase difference angles depend on dimensionless parameters: the inclination angle parameter, the intense vibration parameter, and the index of asymmetry of normal oscillations – the ratio of the maximal acceleration to the gravitational acceleration. Comparison of vibratory conveying by normal oscillations with piecewise constant acceleration to conveying by normal polyharmonic oscillations shows an increase in conveying velocity with the index of asymmetry, equal to the number of harmonics, especially at large inclination angles of a conveying track. For further research, it is proposed to verify the obtained theoretical results through experimental studies.
vibratory conveying velocity; two-component vibration
This paper provides an overview of the functionality of Arc Hydro, one of the components within ArcGIS. The purpose of using GIS, specifically the Arc Hydro component, is to prepare geospatial data (e.g., preprocessing digital terrain models, identifying river networks and watershed areas, etc.) during the pre-modeling phase within HEC-HMS. Arc Hydro provides a set of standardized attributes and a toolset for implementing the data model. The Arc Hydro tools generate several datasets that collectively describe the drainage pattern of a catchment. These tools are installed as an Arc Hydro toolbar, which includes the Terrain Preprocessing menu. This menu provides functions dealing with DEM processing and is mostly used once to prepare spatial information for later use. Arc Hydro is not a hydrologic modelling software but an excellent free tool to facilitate hydrologic modelling of watersheds. It is a unique GIS program that maintains the connectivity of hydrologic features. Using the example of the Bioštica River Basin, this paper will demonstrate the pre-modeling steps utilizing Arc Hydro. Additionally, the results obtained during the pre-modeling phase serve as the foundation for the watershed delineation method, using the Point Delineation option (which allows interactive delineation of a watershed upstream of a user-specified point). In this way, the study defines the watershed area for the Hydrological Station HS Bioštica, Bioštica River. Compared to the manual subwatershed and stream network delineation approach, the Arc Hydro toolbar offers significant time savings.
ArcGIS; Arc Hydro; Bioštica River Basin; Point Delineation; HS Bioštica; river Bioštica
High Impedance Arc Fault Modelling in Offshore Oil Platform Power Grid
In offshore oil platform power grid, high impedance arc fault occurs frequently. The fault characteristics of high- impedance arc information are weak and difficult to detect, which may not cause the protection method to activate. Therefore, it is important to detect and clear the high impedance fault. In the high impedance case, usually, the arc fault occurs. In the research, the arc model was established using the typical Cassie model, and the high impedance arc fault characteristics in offshore oil platform power grids were analysed. An improved arc fault detection method using the phase angle difference between zero sequence voltage and zero sequence current was proposed to extract fault characteristics. This method requires limited detection information and high accuracy to solve the problem of small current and voltage changes in high-resistance arc faults. The offshore oil platform power grid and the arc were modelled using electromagnetic transients software PSCAD/EMTDC. The simulation results show that the arc model and fault detection method work well.
offshore power grid; high impedance fault; Cassie model; PSCAD/EMTDC
Stochastic Approach in Performance Modelling of a Repairable Industrial System
This paper aims to present a quantitative investigation of a case study based on a live industrial refrigeration system exhibiting complex and dynamic behaviour such as randomness, concurrency, and time dependency. The study employs a state-space stochastic Markovian process to model the interactions among the key functional elements of the system. Furthermore, the scientific approach pursued in this study would help improve the availability of the considered plant by establishing a trade-off between investment, economy, and quality. Based on the analysis of results, a framework for Decision Support Priorities (DSP) is proposed, emphasizing the criticality of various functional units. This framework could also help set and prioritize maintenance, spare parts, and human resource requirements accordingly.
Markov chains; Petri nets; Performance modelling; RAM
Development of Laser Heat Treatment Process for Assisted Forming of Aluminum Alloys
This study presents information regarding the development of a localized laser-induced heat treatment for aluminum alloys. Such a process is intended to improve the forming behavior of aluminum parts in challenging metal-forming conditions. This study details information on material, heat treatment parameters as well as results for strength, hardness, and elongation properties. It was concluded that it is possible to locally modify yield strength and hardness using laser control parameters and process duration suitable for industrial applications.
aluminum alloy; metal forming; heat treatment; laser processing
Modelling of Elastohydrodynamic Step Bearing Considering Adsorbed Layer and Surface Roughness
The operation of the elastohydrodynamic lubricated step bearing is analytically investigated when operating with low clearance and surface roughness. In this bearing, there is a sandwich film containing two adsorbed layers and an intermediate fluid film. Using Zhang’s multiscale flow model, the calculations were performed numerically to determine the film pressure and lubricating film thickness distributions. The results show that the elastic deformations of the coupled surfaces greatly affect the performance of the bearing, especially when the adsorption of the adhering layer is stronger or/and the surface is rougher; For a given load, it significantly reduces the magnitude of the highest pressure and modifies the pressure distribution, and it also reduces the minimum clearance and modifies the surface separation profil.
adhering layer; elastic deformation; hydrodynamic; mixed lubrication; step bearing
Multi-objective Optimization in EDM Process Using Backpropagation Neural Network-Genetic Algorithm (BPNN-GA)
Surface roughness (SR) and material removal rate (MRR) are performance evaluations of the electrical discharge machine (EDM) Sinking process. They depend on the process variables inputted in the EDM Sinking. In this study, an attempt was made to improve the sinking EDM process to increase MRR and decrease SR in AISI P20 materials with process variables such as electrode type, pulse on time (Ton), pulse off time (Toff), and gap voltage (GV). The Taguchi method’s L18 orthogonal array is employed in the experiment. Analysis of variance (ANOVA) was performed to determine the influence of the process parameters on the response parameters. The experiment was completed with 18 triels with two replicates. The proposed method for modelling and optimization is the Backpropagation Neural Network (BPNN) combined with Genetic Algorithm (GA). The BPNN is developed based on the process variables and the responses measured during the experiments. The developed BPNN model is fed into the GA algorithm. Based on the modelling and optimization results of both methods, an error of less than 5% is obtained, which proves that the hybrid BPNN-GA methods are acceptable.
Electrical Discharge Machine (EDM) Sinking; Surface Roughness (SR); Material Removal Rate (MRR); Backpropagation Neural Network (BPNN); Optimization; Genetic Algorithm (GA); Analysis of Variance (ANOVA)
Multi-Objective Optimisation-Oriented Model of an Air-Conditioned Environment
A dynamic modelling of a workplace in an area with high temperature and low humidity in the summer is described. The aim is to subsequently use the model to apply multi-objective predictive supervision of the environment climate. Two main variables are modelled: thermal comfort and energy consumption. First, a model of the different temperatures, humidity levels and the behaviour of the air-conditioning system is created. These variables respond to two control actions: the setpoint of the air-conditioning system and the speed of an airflow that may come from outside, and to a disturbance, the external temperature. The overall model is disintegrated into sub-models that precisely describe the internal influences between the variables. This model provides new insights on the subject in that it correctly describes the dynamic behaviour of the system by using simple Linear Parameter Varying descriptions to model the non-linear relationships, incorporates humidity into the thermal comfort model, includes forced ventilation of outside air as a strategy to reduce electricity consumption, defines a relative power unit that simplifies the measurement of electrical consumption, and its methodology is easy to apply to other environments. Different experiments demonstrate that the model accurately depicts the actual variables.
Dynamic model; air-conditioning; thermal comfort; energy consumption; multi-objective predictive supervision
Design and Numerical Analysis of E-D Nozzle with Throat Radius Investigation in Supersonic Flows: A Comparison Study with Tic Nozzle
The design of supersonic E-D nozzles is crucial for enhancing the performance of jet engines in supersonic aircraft by increasing thrust and improving overall efficiency. The aim of this study is to develop an E-D nozzle design and to investigate the influence of the central body radius on the flow characteristics and efficiency of the nozzle. The results show that increasing the radius of the central body leads to a reduction in nozzle length, wall surface area, and thrust. The ANSYS-Fluent software was used to compare an E-D nozzle and a TIC nozzle with the same surface area ratio. The results of the study show that the E-D nozzle is smaller in size than the TIC nozzle with the same cross-sectional area ratio. For over-expanded flow conditions, the flow adheres to the walls of the E-D nozzle, while it detaches from the walls of the TIC nozzle. In addition, the E-D nozzle delivers a significantly higher thrust than the TIC nozzle, with an estimated increase rate of 12.97 %.
E-D (expansion-deflection) nozzle; TIC nozzle; ANSYS-Fluent; FORTRAN; Prandtl–Meyer expansion
Modelling a Contention-Based Wireless MAC Protocol with EDCA Countdown and Constrained Priority Freezing
Analytical modelling is an important part of distributed wireless MAC protocol research and analysis. Most of the protocols proposed in the literature are based on a countdown and use one of two different countdown types: DCF or EDCA type, both defined in the IEEE 802.11 group of standards. The difference between the two countdowns is seemingly negligible, but it can lead to remarkable differences in network performance. In this paper, a new model of a simple protocol is developed that uses an EDCA type of countdown and employs a constrained priority freezing mechanism. It is based on a three-dimensional Markov chain that represents the operation of a single observed station. The model is validated by comparing the numerical results with the simulation results and shows a very high degree of accuracy. Therefore, the proposed model should serve as a basis for the development of more complex models of protocols using EDCA countdown with constrained priority freezing.
MAC modelling; EDCA countdown; constrained priority freezing; saturation throughput
Thermoelastic Effect in a Large Lubricated Thrust Bearing
The numerical simulation results are presented for the performance of a large lubricated thrust bearing, considering surface elasticity and surface thermal distortion under large loads and high sliding speeds. The bearing shaft and bush are respectively made of steel and bronze. The results show that the film thickness and film pressure profiles were largely changed by the surface thermal distortion. Due to the surface thermoelastic effect, a large load results in a minimum lubricating film thickness that is far smaller than that predicted by conventional hydrodynamic lubrication theory calculation, and the minimum film thickness is much more sensitive to load variation than predicted by conventional hydrodynamic lubrication theory description. The minimum film thickness does not vary with an increase of the sliding speed when the sliding speed is sufficiently high. The effect of the adsorbed layer considerably increases the minimum film thickness, which is below 100 nm, particularly in the case of strong fluid-bearing interaction.
adsorbed molecule; film pressure; film thickness; thermoelastic deformation; thrust bearing
Modal Evaluation of Reinforced Cement Concrete Tall Buildings Using ETABS
The planning and construction of tall buildings are regulated by lateral forces such as seismic and wind loads. It is imperative to perform a modal analysis of the framework before performing the dynamic evaluation of the building when subjected to lateral forces. Consequently, building professionals focus on calculating the inherent frequency and associated natural period in tall structures to assess the vibrational behaviour of the building's frame. The current research aims to investigate and evaluate the performance of various tall building frameworks with differing shear wall configurations under free vibration, as the arrangement of shear walls significantly influences the stability of the structure against lateral forces. This investigation employs the eigenvalue estimation method for examining rectangular buildings with various shear wall configurations using the FEM program ETABS. The outcomes of this research include predictions of the natural frequency and mode shape for numerous tall rectangular building simulations with numerous configurations of shear wall components by modal simulation. The natural frequency range, time period, mode shapes, and mass participation factors were extracted from the data. As the model’s stiffness increases due to the incorporation of shear wall, the natural time period diminishes across each configuration It is imperative to perform. The model incorporating centrally positioned shear walls in a core configuration demonstrated a 35% reduction in the fundamental time period compared to rectangular structures without shear walls. The investigation is restricted to the modal evaluation of tall rectangular building frameworks and does not include uncertainty quantification (UQ).
high-rise building; Finite Element Method; ETABS simulations; free vibration; eigenvalue
Modelling of Elastohydrodynamic Journal Bearing with Ultra-Small Clearances
This paper presents the numerical calculation for the elastohydrodynamic journal bearing with ultra-small clearances (with the eccentricity ratios approaching unity), where in a local small area only the physically adsorbed layer is present, while in the other areas the sandwich film is present. It is shown that both the adsorbed layer and the elastic deformation of the surface strongly influence the performance of the bearing. For a given operating condition, the surface elastic deformation causes significant reductions in both the maximum hydrodynamic pressure and the load of the bearing, while it significantly increases the minimum clearance (for a given eccentricity ratio) and the friction coefficient. The surface elastic deformation also increases film stiffness. These effects are strongly dependent on the fluid-surface interaction; the stronger the fluid-surface interaction, the more significant the effect of the surface elastic deformation. The present study shows the considerable benefit of the adsorbed layer formed by the strong fluid-surface interaction in increasing the bearing minimum clearance (for a given load or a given eccentricity ratio) and reducing the friction coefficient of the bearing when the surface elastic deformation is involved.
adsorbed layer; elastic deformation; friction coefficient; hydrodynamics; journal bearing; load; pressure
Numerical Analysis of Two Models of Air Deflectors to Improve the Aerodynamics of a Heavy Truck
Fuel consumption and pollutant gas emissions are major issues that affect the heavy-duty truck industry. The installation of air deflectors on the roof of truck cabins is a widely adopted strategy to reduce drag and improve aerodynamics. The latter is directly related to fuel consumption and pollutant gas emissions. This study aims to identify the optimal air deflector design to improve aerodynamic performance. Seven vehicle body configurations were modelled using SolidWorks 3D design software: a basic model (truck without a deflector) and six models equipped with deflectors. Computational fluid dynamics (CFD) analyses were conducted for each configuration to determine the most aerodynamically efficient structure. The results reveal that models with air deflectors achieved reductions in static pressure (ranging from 0.17% to 1.73%) and velocity (ranging from 1.2% to 5%) compared to the basic model. These findings confirm the critical role of air deflectors in enhancing aerodynamic performance and reducing drag force. Among the different models, the first deflector (case 1) stands out for its best performance, with an estimated drag coefficient reduction of 19.80% and a corresponding decrease in fuel consumption of 19.79%. In conclusion, these results show that drag reduction directly impacts fuel economy.
air deflector; drag coefficient; fuel saving; velocity; truck
Maxwell’s and Wave Equations in Media Containing Electromagnetic Field Sources
This paper presents a new system of Maxwell’s equations and corresponding wave equations for conducting media containing electromagnetic field sources. The theoretical approach begins with a consistent generalisation of Maxwell’s differential equations in a slowly moving conducting medium. From this generalised form, both differential and integral forms of Maxwell’s equations are derived for slowly moving and stationary conducting media. The well-known Maxwell’s equations for a perfect dielectric containing sources appear as a special case of the equations for a conducting medium containing sources. Notably, Maxwell’s third differential equation is derived from the first, resulting in a new form of the third equation specific to conducting media. This revised equation differs from the traditional form valid in perfect dielectrics – namely, Gauss’s law for the electric field – which holds in a conducting medium only when the medium is linear, isotropic, homogeneous and source-free. A key contribution of this work is the introduction of the volume density of the source leakage electric current in conducting media as a novel physical quantity, analogous to the volume charge density in perfect dielectrics. The volume density of the leakage electric current injected by the source into the surrounding medium is reduced to the volume density of the displacement electric current in the case of a dielectric, where the conducting component is absent. Finally, wave equations for electromagnetic fields and electromagnetic potentials are derived from the generalised Maxwell’s differential equations.
Maxwell’s equations; wave equations; electromagnetic field sources; conducting media; perfect dielectrics; volume density of the source leakage electric current
Heat Field Characteristics of Solid Domain of Nozzle Flowmeter with Different Weld Structures
In this paper, four weld structures with a total of 10 distinct welds were produced and the effect of weld structures on the heat flow field within the solid wall of the nozzle flowmeter is thoroughly investigated by numerical calculations. The results show that, on the path from upstream to downstream, the distance between the weld and nozzle, the width below the weld, the taper angle and the opening have less influence on the heat flow distribution. On the path from the inner to the outer wall, the taper angle and the opening have a greater effect on the peak and the maximum magnitude of the total heat flow, and the peak and the maximum magnitude of the total heat flow for big taper angle and opening welds are much bigger than those under small taper angle and opening welds. The distance between the weld and nozzle, the width below the weld, the taper angle and the opening significantly affect the heat flow distribution of the path section near 0.2 times the length of the monitoring path. However, the heat flow distribution inside the nozzle flowmeter is minimally affected by the distance between the weld and nozzle, the width below the weld, the taper angle and the opening.
nozzle flowmeter; weld structure; heat flow analysis; numerical calculation
Early Detection and Classification of Cancer Histology Images Using Artificial Intelligence Techniques: A Review
Cancer is one of the most serious diseases that humans face nowadays, and, until now, no permanent remedy has been developed for it, especially in the case of advanced stages. Cancer is characterised by uncontrolled multiplication and abnormal growth of cells until tumour formation and organ destruction. Early detection and diagnosis are imperative to reduce the number of mortalities, which has progressively declined in recent years thanks to more advanced computer-aided diagnosis systems (CADS). Artificial intelligence and machine learning have been successfully applied to detect and treat various dangerous diseases. It is more accurate to use histopathological imaging to detect cancers such as breast, lung, and brain cancer in the early stage based on more important features. In this paper, we review previous work on various types of cancer using microscopic and histopathological imaging as datasets on different deep learning and artificial intelligence models for classifying abnormalities. The aim is to provide a comprehensive view of the existing techniques and datasets for detecting and classifying histopathological images.
cancer detection; histopathological imaging; artificial intelligence; medical image analysis
Modelling and Analysis of Three-Dimensional Maxwell-Nanofluid Flow over a Bi-Directional Stretching Surface in the Presence of a Magnetic Field
This work models a three-dimensional, steady, incompressible, viscous, non-Newtonian Maxwell fluid flow over a bidirectional stretching surface, both computationally and numerically. Under Brownian motion, thermophoresis, thermal, and mass Biot numbers, the effects of Soret and Dufour on three-dimensional upper-convected Maxwell-Nanofluid flow across a bidirectional stretching surface are examined in the current study. The latest information on the unique and innovative properties of nanofluids is also provided. The energy equation includes a nonlinear radiative heat flow, according to the Rosseland approximation. By adding applicable dimensionless variables and parameters, the governing equations are converted to dimensionless form and solved via a finite element system. The study provides a thorough examination of the ways different variables and other relevant parameters affect the flow variables. These findings are made visually clear and offer valuable insight into the flow scenario using graphical representations. The results indicate that the plan is appropriate for solving the current issue. This new research has implications for energy systems, biomedical engineering, and aeronautics, as well as significant implications for the food industry. This investigation's numerical findings are felt and validated.
Maxwell-nanofluid; finite element method; magnetic field; three-dimensional; thermal Biot number; mass Biot number
Importance of the Johnson-Cook Material Model Parameters in Simulation Studies of the Cutting Process
Computer simulations of various manufacturing processes have become increasingly common in recent years. In machining, their primary goal is to rationalize the planning of experimental studies and to observe phenomena occurring in the cutting zone that cannot be observed otherwise. Another significant aspect is the ability to numerically verify many different process variants before conducting an experiment. Simulations are run based on an appropriate material model describing the tribomechanical behaviour of the material. Typically, this is the Johnson-Cook model, represented by five numerical parameters. However, to properly select the J-C model for calculations, one must understand how individual parameters affect the final simulation outcome. This study shows that it is possible to select many different sets of J-C model parameters that meet the equation conditions but yield different simulation results. Therefore, this paper shows the influence of individual numerical parameters of the J-C model on the simulation results, such as cutting forces, temperature distribution, chip morphology, etc. The tests and analyses presented in this paper were performed for AISI 321 austenitic steel.
machining; numerical simulations; material model; J-C model parameters
3D Digital Image Virtual Scene Reconstruction Algorithm Based on Machine Learning
3D modeling has been widely used in industrial, medical, military and other fields. Trying to solve the issue that the traditional 3D reconstruction model is ineffective in processing digital image feature extraction in virtual scenes, this study adopts a multi-view stereo vision algorithm and neural network to optimize it based on the traditional 3D reconstruction algorithm. Then, the spatial attention mechanism and the channel attention mechanism were combined to generate a Convolutional Block Attention Module (CBAM) model, and the CBAM was used in a multi-view stereo vision algorithm model. The model's performance is tested, and it is found that the convergence speed is faster in training, the loss function value is lower, and the overall model's performance is better. In the test, compared with the other three models, the accuracy of the proposed model is improved by 17%, 9% and 3% on average. The integrity of MVSNet-CBAM was enhanced by 28%, 14% and 9%, respectively. The experiment verifies the validity, which aims to provide a reference for 3D digital image virtual scene reconstruction.
neural network; three-dimensional model; reconstruction algorithm; attention mechanism; multi-view stereo vision algorithm
Copyright (c) 2025 https://creativecommons.org/licenses/by/4.0
Optimal Rebate Policy in a Green Product Design and Development System with Price-Sensitivity Demand
Green product design and development should be an eco-design tool for waste management throughout the design and disposal stage. Return and recycling policy plays a crucial role in a recycling system through government subsidies. To reduce raw material waste and improve energy efficiency within recycling systems, the rebate policy is proving to be a valuable tool for companies striving to achieve ambitious targets in returning used bikes on the streets. This paper contributes to investigating the role of rebate policy on a two-stage integrating optimizing model with multiple components and imperfect processes based on price-sensitivity demand. The paper aims to deepen our understanding of the role of the return policy in a profit-maximizing remanufacturing system. An algorithm analyzes optimal solutions for production and usage rebate policies to maximize the total profit per unit time. Despite inherent limitations, data from the Taiwan bike company are used to illustrate the proposed model and algorithm. Additionally, sensitivity analysis is conducted to derive valuable managerial insights.
rebate policy; recycling system; green product design and development; bike industry; economic production quantity
An Electric Oven Identification Using Step Response Based on the Prony Approach
Ovens are devices commonly used to in laboratories and industry provide temperature conditions for drying, cooking and chemical processes. Developing an accurate mathematical model is an important step before designing a controller for this system. In this study, an electric oven was tested with pulse and step inputs. The Prony curve fitting method was used to fit the step response of the oven to that of a typical nth order Linear Time-Invariant (LTI) system. The decision to use the step response for identification was based on two reasons. First, the oven is a high-order dynamic system with input constraints that make it practically impossible to obtain the impulse response. Secondly, the step input ensures the persistence of excitation and is easy to apply. Adapting Prony's method, which usually uses the impulse response, to work with pulse and step responses required some theoretical modifications. Finally, different model orders were evaluated using the Akaike information function, and it was found that a 17th order LTI system best describes the behaviour of the oven system. The discrete and continuous Transfer Functions (TFs) for this well-fitted model were determined.
system identification; electric oven; Prony approach; step response; Akaike information criterion