mathematical formulation
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Electronics ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 275
Author(s):  
Ljiljana Šerić ◽  
Antonia Ivanda ◽  
Marin Bugarić ◽  
Maja Braović

This paper presents a semantic conceptual framework and definition of environmental monitoring and surveillance and demonstrates an ontology implementation of the framework. This framework is defined in a mathematical formulation and is built upon and focused on the notation of observation systems. This formulation is utilized in the analysis of the observation system. Three taxonomies are presented, namely, the taxonomy of (1) the sampling method, (2) the value format and (3) the functionality. The definition of concepts and their relationships in the conceptual framework clarifies the task of querying for information related to the state of the environment or conditions related to specific events. This framework aims to make the observation system more queryable and therefore more interactive for users or other systems. Using the proposed semantic conceptual framework, we derive definitions of the distinguished tasks of monitoring and surveillance. Monitoring is focused on the continuous assessment of an environment state and surveillance is focused on the collection of all data relevant for specific events. The proposed mathematical formulation is implemented in the format of the computer readable ontology. The presented ontology provides a general framework for the semantic retrieval of relevant environmental information. For the implementation of the proposed framework, we present a description of the Intelligent Forest Fire Video Monitoring and Surveillance system in Croatia. We present the implementation of the tasks of monitoring and surveillance in the application domain of forest fire management.


Author(s):  
Simone König ◽  
Maximilian Reihn ◽  
Felipe Gelinski Abujamra ◽  
Alexander Novy ◽  
Birgit Vogel-Heuser

AbstractThe car of the future will be driven by software and offer a variety of customisation options. Enabling these customisation options forces modern automotive manufacturers to update their standardised scheduling concepts for testing and commissioning cars. A flexible scheduling concept means that every chosen customer configuration code must have its own testing procedure. This concept is essential to provide individual testing workflows where the time and resources are optimised for every car. Manual scheduling is complicated due to constraints on time, predecessor-successor relationships, mutual exclusion criteria, resources and status conditions on the car engineering and assembly line. Applied methods to handle the mathematical formulation for the corresponding industrial optimisation problem and its implementation are not yet available. This paper presents a procedure for automated and non-preemptive scheduling in the testing and commissioning of cars, which is built on a Boolean satisfiability problem on parallel and identical machines with temporal and resource constraints. The presented method is successfully implemented and evaluated on a variant assembly line of an automotive Original Equipment Manufacturer. This paper is the starting point for an automated workflow planning and scheduling process in automotive manufacturing.


Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 170
Author(s):  
Panayiotis Vafeas ◽  
Eleftherios Protopapas ◽  
Maria Hadjinicolaou

Modern engineering technology often involves the physical application of heat and mass transfer. These processes are associated with the creeping motion of a relatively homogeneous swarm of small particles, where the spheroidal geometry represents the shape of the embedded particles within such aggregates. Here, the steady Stokes flow of an incompressible, viscous fluid through an assemblage of particles, at low Reynolds numbers, is studied by employing a particle-in-cell model. The mathematical formulation adopts the Kuwabara-type assumption, according to which each spheroidal particle is stationary and it is surrounded by a confocal spheroid that creates a fluid envelope, in which the Newtonian fluid moves with a constant velocity of arbitrary orientation. The boundary value problem in the fluid envelope is solved by imposing non-slip conditions on the surface of the spheroid, which is also considered as non-penetrable, while zero vorticity is assumed on the fictitious spheroidal boundary along with a uniform approaching velocity. The three-dimensional flow fields are calculated analytically for the first time, in the spheroidal geometry, by virtue of the Papkovich–Neuber representation. Through this, the velocity and the total pressure fields are provided in terms of a vector and the scalar spheroidal harmonic potentials, which enables the thorough study of the relevant physical characteristics of the flow fields. The newly obtained analytical expressions generalize to any direction with the existing results holding for the asymmetrical case, which were obtained with the aid of a stream function. These can be employed for the calculation of quantities of physical or engineering interest. Numerical implementation reveals the flow behavior within the fluid envelope for different geometrical cell characteristics and for the arbitrarily-assumed velocity field, thus reflecting the different flow/porous media situations. Sample calculations show the excellent agreement of the obtained results with those available for special geometrical cases. All of these findings demonstrate the usefulness of the proposed method and the powerfulness of the obtained analytical expansions.


Author(s):  
Muhammad Yasir ◽  
Awais Ahmed ◽  
Masood Khan ◽  
Zahoor Iqbal ◽  
Muhammad Azam

The most important and significant research topic in mechanical and industrial engineering is the fluid flow with heat transport by a stretched surface because of the numerous applications. The impact of heat transport on product quality can be noticed in the field of chemical engineering, polymer processing, glass fiber production, hot rolling, metal extrusion, production of paper, and drawing of plastic films and wires. In light of such foregoing applications, an attempt is made to model the thermal and solutal diffusion phenomena in Oldroyd-B nanofluid flow over a stretching cylinder by using Buongiorno's model and Cattaneo-Cristov theory. To explore the heat flow mechanism in the flow, the effects of heat source/sink with ohmic heating are also considered. Additionally, the influence of chemical reactions is used to investigate the solutal transport process in nanofluid flow. The mathematical formulation section of the manuscript depicts the mathematical modeling of momentum, heat, and mass diffusion equations. The effect of dimensionless physical constraints on the flow, temperature, and concentration distributions of Oldroyd-B nanofluid flow are investigated using the homotopy analysis method (HAM) in Wolfram Mathematica. In the results and discussion section, graphical findings are displayed and physically justified. A section of concluding remarks is added at the end of the text to emphasize the study's major findings.


Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 505
Author(s):  
Oleksandr Ivchenko ◽  
Vitalii Ivanov ◽  
Justyna Trojanowska ◽  
Dmytro Zhyhylii ◽  
Olaf Ciszak ◽  
...  

The paper presents a constructing methodology for a modern approach to tools selection and solving the problem of assigning optimal cutting parameters for specific production conditions. The mathematical formulation determining the extreme values of the technological process optimality criteria is obtained. A system of technical and economic quality indicators for cutting tools is proposed. This system allows principles’ implementation of decentralization and interoperability “Industry 4.0” via finite element modeling of the cutting process based on solving the problem of orthogonal free cutting modeling. The proposed methodology further usage is possible by creating a standardized database on the parameters of the tool: the adhesive component of the friction cutting coefficient for processing of a specific pair of cutting and tool materials (or tool coating material) and the impacts of the cutting-edge radius on cutting efficiency of a particular material.


Author(s):  
Wassim Lafi ◽  
Fathi Gharbi ◽  
Ali Akrout ◽  
Mohamed Haddar

The presence of a differential mechanism is fundamental in most automotive applications. Its importance stems from allowing a vehicle to take a curve. The differential should be well-lubricated to ensure its smooth operation and mitigate its vibration level. With lubrication conditions deteriorating over time, the sliding friction coefficient becomes difficult to predict its accurate value. Thus, scrutinizing the dynamic performance of the mechanism with deterministic sliding friction can be misleading. This paper aims to investigate the dynamic performance of the automotive differential with the presence of interval sliding friction. To this end, a 3D dimensional model of automotive differential with time-varying mesh stiffness (TVMS) and bearing flexibility is proposed. The influence of sliding friction on TVMS for straight bevel gear is revealed. The Newton-Euler formulation is used to derive the dynamic equations governing the motions of the automotive differential with friction. The Chebyshev inclusion function and the least square method are used to deal with the interval mathematical formulation of the model. The scanning method is used as a reference method in this paper. There are quite similarities between the results derived by the scanning method and that of the interval process method. The reliability analysis of the differential is conducted. The outcome of this research shows that any variation of the sliding friction can alter the dynamic performance of the differential significantly. The differential is more sensitive to the friction coefficient between the ring gear and the drive pinion and between the left-side gear and two planets. The findings should make an important contribution to the analysis of the differential mechanism.


2022 ◽  
Vol 14 (1) ◽  
pp. 512
Author(s):  
Mir Waqas Alam ◽  
Syed Ghazanfar Hussain ◽  
Basma Souayeh ◽  
Muhammad Shuaib Khan ◽  
Mohd Farhan

This write-up presents a closure to the comments of Awad, M.M. (2021) on the paper “Numerical Simulation of Homogeneous–Heterogeneous Reactions through a Hybrid Nanofluid Flowing over a Rotating Disc for Solar Heating Applications” (Alam et al., 2021). The authors have addressed each of the comments in detail to uphold the correctness of the mathematical formulation together with the pertinent results presented in our published article.


2022 ◽  
Vol 14 (1) ◽  
pp. 491
Author(s):  
Chunxiao Zhao ◽  
Junhua Chen ◽  
Xingchen Zhang ◽  
Zanyang Cui

This paper presents a novel mathematical formulation in crew scheduling, considering real challenges most railway companies face such as roundtrip policy for crew members joining from different crew depots and stricter working time standards under a sustainable development strategy. In China, the crew scheduling is manually compiled by railway companies respectively, and the plan quality varies from person to person. An improved genetic algorithm is proposed to solve this large-scale combinatorial optimization problem. It repairs the infeasible gene fragments to optimize the search scope of the solution space and enhance the efficiency of GA. To investigate the algorithm’s efficiency, a real case study was employed. Results show that the proposed model and algorithm lead to considerable improvement compared to the original planning: (i) Compared with the classical metaheuristic algorithms (GA, PSO, TS), the improved genetic algorithm can reduce the objective value by 4.47%; and (ii) the optimized crew scheduling plan reduces three crew units and increases the average utilization of crew unit working time by 6.20% compared with the original plan.


2022 ◽  
Vol 2150 (1) ◽  
pp. 012013
Author(s):  
K M Moiseeva ◽  
A Yu Krainov

Abstract The paper presents a mathematical model and the results of a numerical study of the flame propagation of a methane-air mixture. The physical and mathematical formulation of the problem takes into account the thermal expansion of the gas and its subsequent movement. The problem was solved numerically using the Van Leer method to determine the fluxes at the boundaries of the computational cells. A study of flame propagation in a methane-air mixture with a methane content less than or equal to stoichiometric has been carried out. The conditions for focal ignition of a reactive mixture are determined. The influence of the channel walls on the features of flame propagation is shown. The necessity of taking into account the non-isobaricity of the combustion process at the initial stage is demonstrated.


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