Open Journal of Modelling and Simulation

Journal Information
ISSN / EISSN : 2327-4018 / 2327-4026
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 138
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Latest articles in this journal

Shiblu Sarker
Open Journal of Modelling and Simulation, Volume 10, pp 1-31; https://doi.org/10.4236/ojmsi.2022.101001

Abstract:
The term “hydraulics” is concerned with the conveyance of water that can consist of very simple processes to complex physical processes, such as flow in open rivers, flow in pipes, the flow of nutrients/sediments, the flow of groundwater to sea waves. The study of hydraulics is primarily a mixture of theory and experiments. Computational hydraulics is very helpful to quantify and predict flow nature and behavior. The mathematical model is the backbone of the computational hydraulics that consists of simple to complex mathematical equations with linear and/or non-linear terms and ordinary or partial differential equations. Analytical solution to these mathematical equations is not feasible in the majority of cases. In these consequences, mathematical models are solved using different numerical techniques and associated schemes. In this manuscript, we aim to review hydraulic principles along with their mathematical equations. Then we aim to learn some commonly used numerical techniques to solve different types of differential equations related to hydraulics. Among them, the Finite Difference Method (FDM), Finite Element Method (FEM) and Finite Volume Method (FVM) have been discussed along with their use in real-life applications in the context of water resources engineering.
Temitayo Emmanuel Olaosebikan, Friday Ogoigbe Egbon, Kehinde Samuel Olayemi
Open Journal of Modelling and Simulation, Volume 10, pp 283-291; https://doi.org/10.4236/ojmsi.2022.103015

Abstract:
Mathematics is a key factor in achieving the Sustainable Development Goals (SDGs), because of its applicability to real situations. To achieve the set goals in SDG, this paper suggests some mathematical methods that will be useful for solving real situations in relation to goals 2 and 12 of SDGs approved by UN when modeled mathematically. The Northwest Corner Method (NWCM), Least Cost Method (LCM), and Vogel Approximation Method (VAM), which are the initial solution methods were examined to ascertain the ideal route of transporting commodities from production facilities to requirement destination while the optimal solution methods involve Stepping Stone Method (SSM), and Modified Distribution Method (MDM), that give the feasible solution which will enhance minimum transportation cost were also thoroughly defined. Subsequent research shall focus on application of the methods in relation to SDGs problems in comparison with other existing methods.
Romana Bauer, Florian Schwarzmayr, Norbert Brunner, Manfred Kühleitner
Open Journal of Modelling and Simulation, Volume 10, pp 152-164; https://doi.org/10.4236/ojmsi.2022.102009

Abstract:
The organic food market has become an important part of food industry. We analyze sales data from Austria for 2014 to 2020 of 124 products from 25 product groups in six categories, each in conventional and organic form. We fitted their market shares by means of a modified Lotka-Volterra model with constant coefficients. When only organic and conventional products were compared, a significant increase in market shares was observed for 15 of 25 organic product groups, indicating a continuing growth of the organic food market. The typical Lotka-Volterra dynamics was a predator-prey dynamics with an organic product (group) predating on conventional products that were in symbiosis.
Leif Gustafsson, Erik Gustafsson, Magnus Gustafsson
Open Journal of Modelling and Simulation, Volume 10, pp 219-253; https://doi.org/10.4236/ojmsi.2022.102012

Abstract:
It is vital that a well-defined conceptual model can be realized by a macro-model (e.g., a Continuous System Simulation (CSS) model) or a micro-model (e.g., an Agent-Based model or Discrete Event Simulation model) and still produce mutually consistent results. The Full Potential CSS concept provides the rules so that the results from macro-modelling become fully consistent with those from micro-modelling. This paper focuses on the simulation language StochSD (Stochastic System Dynamics), which is an extension of classical Continuous System Simulation that implements the Full Potential CSS concept. Thus, in addition to modelling and simulating continuous flows between compartments represented by “real” numbers, it can also handle transitions of discrete entities by integer numbers, enabling combined models to be constructed in a straight-forward way. However, transition events of discrete entities (e.g., arrivals, accidents, deaths) usually happen irregularly over time, so stochasticity often plays a crucial role in their modelling. Therefore, StochSD contains powerful random functions to model uncertainties of different kinds, together with devices to collect statistics during a simulation or from multiple replications of the same stochastic model. Also, tools for sensitivity analysis, optimisation and statistical analysis are included. In particular, StochSD includes features for stochastic modelling, post-analysis of multiple simulations, and presentation of the results in statistical form. In addition to making StochSD a Full Potential CSS language, a second purpose is to provide an open-source package intended for small and middle-sized models in education, self-studies and research. To make StochSD and its philosophy easy to comprehend and use, it is based on the System Dynamics approach, where a system is described in terms of stocks and flows. StochSD is available for Windows, macOS and Linux. On the StochSD homepage, there is extensive material for a course in Modelling and Simulation in form of PowerPoint lectures and laboratory exercises.
Siaka Touré
Open Journal of Modelling and Simulation, Volume 10, pp 48-57; https://doi.org/10.4236/ojmsi.2022.101003

Abstract:
Several studies on PV solar cells are found in the literature which use static models. Those models are mainly one-diode, two-diode or three-diode models. In the dynamic modelling, a variable parallel capacitance is incorporated. Unlike the previous studies which do not clearly establish a relationship between the capacitance and the voltage, in the present paper, the link between the capacitance and the voltage is investigated and established. In dynamic modelling investigated in this paper, the dynamic resistance is introduced in the modelling of the solar cell. It is introduced in the current-voltage characteristic. The value of the dynamic resistance is evaluated at the maximum power point and its effect on the maximum power is investigated. The study shows for the first time, that the dynamic resistance must be introduced in the current-voltage characteristic, because it has an influence on the PV cell output.
Sahar Safarian, Runar Unnthorsson, Christiaan Richter
Open Journal of Modelling and Simulation, Volume 10, pp 71-87; https://doi.org/10.4236/ojmsi.2022.102005

Abstract:
This study presents a reliable model using Aspen Plus process simulator capable of performing a sensitivity analysis of the downdraft gasification linked to hydrogen production unit. Effects of key factors, including gasification temperature and steam to biomass ratio (SBR) on the syngas composition, calorific value of syngas and hydrogen production are discussed and then the optimal conditions for maximum hydrogen production are extracted. The model is validated by experimental and other modeling data and found to be in great agreement. The sensitivity analysis results obtained by only using air as gasification agent indicate that higher temperatures are favorable for a product gas with higher hydrogen content and calorific value. Moreover, steam consumption as gasifying agent leads to increasing the hydrogen content and heating value of the syngas compared to the use of air as gasification agent. Finally, the results show that the optimal conditions to have the highest value of hydrogen output from sawdust downdraft gasification are 800˚C as gasifier temperature and 0.6 for SBR.
Shiblu Sarker
Open Journal of Modelling and Simulation, Volume 10, pp 88-117; https://doi.org/10.4236/ojmsi.2022.102006

Abstract:
Understanding, quantifying, and forecasting water flow and its behavior in environment is made possible by the use of computational hydraulics in conjunction with numerical models, which is one of the most powerful tools currently available. It is made up of simple to complex mathematical equations having linear and/or nonlinear elements, as well as ordinary and partial differential equations, and it is used to solve problems in many areas. In the vast majority of cases, it is not useful to reach analytical solutions to these mathematical equations using conventional methods. In these settings, mathematical models are solved by employing a variety of numerical algorithms and associated schemes. As a result, in this manuscript, we will cover the most fundamental numerical approach, the Finite Difference Method (FDM), in order to reformulate the governing equations for water and sediment flow from a system of partial differential equations to a system of linear equations. As part of our analysis into the inner workings of a computer program known as MIKE 21C, we will attempt to gain a better understanding of the hydrodynamic processes that take place in major rivers in Bangladesh. In addition to that, we will go over some of the most commonly used morphological studies that have been conducted on Bangladesh’s major rivers, including morphological solutions that have been developed in response to water supply concerns.
Xin Chen, Xiaofei Zhang, Weijiang Qiu, Xin Tu
Open Journal of Modelling and Simulation, Volume 10, pp 139-151; https://doi.org/10.4236/ojmsi.2022.102008

Abstract:
The directional angle of the exterior trajectory measurement equipment in the transponder antenna coordinate system is an important basis for interpreting the transponder antenna gain, analyzing the uplink and downlink power of the transponder, and evaluating the measurement and tracking ability of the equipment. The mathematical model established in this paper deduces the direction angle of the exterior trajectory measurement equipment in the transponder antenna coordinate system according to the track information of the flight target, and then obtains the transponder power received by the exterior trajectory measurement equipment combined with the installation position of the transponder, the antenna pattern and the secondary radar formula. It can effectively evaluate the tracking ability of the equipment in measuring segment and adjust the working state of the equipment according to the actual situation. At the same time, it provides a theoretical basis for the ground measurement equipment to receive the transponder power is too low, resulting in the measurement data accuracy is not up to standard, or even lost.
Irina Trifonova, Stefan Z. Stefanov
Open Journal of Modelling and Simulation, Volume 10, pp 58-69; https://doi.org/10.4236/ojmsi.2022.101004

Abstract:
The paper reassesses a survival at tumor recurrence in soft matter. First, the stability of structural motifs under shear in clusters of dipolar spheres is characterized. Next, there are introduced transitions between polymer knots and rhythms of these transitions are obtained. The sensor is built for these rhythms. Treatment, with a tensile force protocol, is modeled, when the tumor in soft matter is observed by the above sensor. Survival probability, at tumor recurrence in soft matter, is defined for the treatment with a tensile force protocol. It is stated that the survival probability at a tensile force protocol treatment in soft matter confirms or specifies the prognostic survival of 32 patients with breast cancer.
Zaki Mrzog Alaofi, Talaat Sayed El-Danaf, Adel Hadhoud, Silvestru Sever Dragomir
Open Journal of Modelling and Simulation, Volume 10, pp 267-282; https://doi.org/10.4236/ojmsi.2022.103014

Abstract:
Over the last few years, there has been a significant increase in attention paid to fractional differential equations, given their wide array of applications in the fields of physics and engineering. The recent development of using fractional telegraph equations as models in some fields (e.g., the thermal diffusion in fractal media) has heightened the importance of examining the method of solutions for such equations (both approximate and analytic). The present work is designed to serve as a valuable contribution to work in this field. The key objective of this work is to propose a general framework that can be used to guide quadratic spline functions in order to create a numerical method for obtaining an approximation solution using the linear space-fractional telegraph equation. Additionally, the Von Neumann method was employed to measure the stability of the analytical scheme, which showed that the proposed method is conditionally stable. What’s more, the proposal contains a numerical example that illustrates how the proposed method can be implemented practically, whilst the error estimates and numerical stability results are discussed in depth. The findings indicate that the proposed model is highly effective, convenient and accurate for solving the relevant problems and is suitable for use with approximate solutions acquired through the two-dimensional differential transform method that has been developed for linear partial differential equations with space- and time-fractional derivatives.
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