Faculty of Engineering, Kragujevac

Permanent URI for this collectionhttps://dspace.unic.kg.ac.rs/handle/123456789/8210

Since 1976, the Faculty of Mechanical Engineering from Kragujevac is a member of the University "Svetozar Markovic" of Kragujevac, now the University of Kragujevac. Since the foundation to the present, the Faculty has been intensively developing and still is developing with significant spatial, personnel and material recuperation.

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Even this small part of the achieved results shows that the Faculty of mechanical Engineering from kragujevac is an institution rich in tradition and with impressive results, recognized in domestic and foreign circles.

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3D printing of hydrodynamic coupling for school education
(2022) Šušteršič, Vanja; Vukašinović, Vladimir; Gordić, Dušan; Josijevic, Mladen
The application of 3D printing technologies in the industry is growing as new possibilities for their application are discovered, which take advantage of their functionalities. Also, today more and more 3D technology is used for educational purposes. Incorporating of 3D printing in the form of production of three dimensional shapes into the teaching process improved the understanding of geometry. Hydrodynamic couplings works on the hydrodynamic principle, which takes place based of the indirect principle of operation. The pump wheel transfers the introduced mechanical energy into the kinetic energy through the fluid flow. The fluid of higher energy flows centrically from the pump wheel to the turbine wheel, where re-conversion to mechanical energy takes place. In this paper, the description and principles of operation of hydrodynamic couplings are presented, as well as their basic characteristics and advantages. Also, the calculation of one hydrodynamic coupling and its 3D model that would be used in the education system are given.
3D reconstruction and computational modeling of solid-fluid interaction in realistic heart model
(2021) Simic, Vladimir; Milosevic, Miljan; Saveljic, Igor; Milicevic, Bogdan; Filipovic, Nenad; Kojić M.
In this report we present basic steps in the 3D reconstruction process of DICOM images and application of our finite element (FE) numerical procedure for loose coupling solid-fluid interaction, to simulate a complete heartbeat cycle for a realistic model of the left heart side. Passive mechanical stresses are calculated using an orthotropic material model based on the experimental investigation of passive material properties of the myocardium, while active stresses are calculated using the Hunter material model. The basic equations for solid mechanics, fluid dynamics, and muscle activation are summarized and model applicability is illustrated on a complex realistic model which includes a left atrium, ventricle, mitral and aortic valves (which serve as fluid domain) coupled with solid wall with realistic fiber directions.
A 130-nm 76-81-GHz SiGe TDM MIMO radar transmitter array for automotive applications
(2021) Krcum D.; Glavonjić E.; Milosavljević, Ivan; Milovanović, Vladimir
A fully-integrated transmitter (TX) for multiple-input multiple-output (MIMO) 79GHz automotive radar applications is presented. The output power scaling and monitoring is implemented in order to enable flexibility and to support robust and reliable operation in complex traffic environments and scenes. The layout of the single channel can easily be replicated to obtain double and quadruple TX arrays. The transmitter delivers 15.12dBm of saturated output power with 11.93dBm output 1-dB compression point, while the peak power-added efficiency simultaneously reaches 15%. The power dissipation of a single TX chain is approximately 265mW from a single 3.3V supply, and scales linearly with the number of chains. Simulated channel gain is 25dB, and covers complete 76-81GHz automotive band of interest. The proposed dual channel transmitter occupies 1.57 mm2 of area, while the quad channel transmitter takes 2.44 mm2, both given as stand-alone chip solutions in the standard industrial SiGe: C HBT 130nm BiCMOS process technology.
A 3-D model of ligand transport in a deforming extracellular space
(2010) Kojić N.; Huang A.; Chung, Euiheon; Ivanović, Miloš; Filipovic, Nenad; Kojić M.; Tschumperlin D.
Cells communicate through shed or secreted ligands that traffic through the interstitium. Force-induced changes in interstitial geometry can initiate mechanotransduction responses through changes in local ligand concentrations. To gain insight into the temporal and spatial evolution of such mechanotransduction responses, we developed a 3-D computational model that couples geometric changes observed in the lateral intercellular space (LIS) of mechanically loaded airway epithelial cells to the diffusion-convection equations that govern ligand transport. By solving the 3-D fluid field under changing boundary geometries, and then coupling the fluid velocities to the ligand transport equations, we calculated the temporal changes in the 3-D ligand concentration field. Our results illustrate the steady-state heterogeneities in ligand distribution that arise from local variations in interstitial geometry, and demonstrate that highly localized changes in ligand concentration can be induced by mechanical loading, depending on both local deformations and ligand convection effects. The occurrence of inhomogeneities at steady state and in response to mechanical loading suggest that local variations in ligand concentration may have important effects on cell-to-cell variations in basal signaling state and localized mechanotransduction responses. © 2010 by the Biophysical Society.
A Brief Overview of Enabling Technologies for Digital Medicine and Smart Healthcare
(2021) Devedzic, Goran; Koceski, Saso; Petrovic Savic S.
Recognizing the ubiquitous dimension of digital and information and communication technologies (ICT) today, healthcare systems accept the advances and possibilities they offer. Two emerging concepts are increasingly gaining the attention of both researchers and entrepreneurs, as well as a wider circle of potential users - these being digital medicine and smart healthcare. Aimed at bridging the gap between traditional healthcare practices and a permanent high increase in population, these two concepts make up for the shortcomings of medical services that are not approachable or affordable to everyone in the changing circumstances. Both are heavily reliant on novel hardware and software technologies that empower patients and healthcare institutions, as well as on wearable, implantable and ingestible medical devices (WIIMD) and digital clinical assets that use internet of things (IoT) network to communicate signals of the patients' physiological traits. This paper overviews in short the current state in the field.
A business intelligence approach for choosing a optimal quality solution
(2016) Djordjevic, Aleksandar; Cvetic T.
The diversity of business processes is very large, and in addition to this diversity between processes there are a number of tools, methods and techniques, especially from the perspective of business intelligence with prominent aspects of their development, the aspect of measurement and analysis of process performance. The purpose of this paper is that for a certain class of problems for which business process are designed to choose certain process model. Through the systematization of the existing models of business processes and methods, techniques and tools for their modeling, the analysis of one class of problems and correspondent business processes has been conducted. In that manner, basis for the new business intelligence optimization model for optimal choice of business processes model is created. To achieve this objective, numerous optimization methods were used from the fields of information engineering, modeling of processes and systems, and decision support systems. In this paper optimization model based on the application of Genetic Algorithm optimization method has been developed.
A Chisel Generator of Parameterizable and Runtime Reconfigurable Linear Insertion Streaming Sorters
(2021) Petrovic M.; Milovanović, Vladimir
Fully streaming linear sorters with their rather simple and low-cost hardware architecture are widely used as the fundamental building blocks in many digital signal processing applications that require sorting operations and continuous data streaming interfaces. Therefore, a parameterizable and runtime reconfigurable generator of fully streaming sorters based on an insertion sort algorithm are captured inside Chisel hardware design language in order to enable fast and efficient agile design space exploration. A broad range of parameter settings are supported with the proposed generator, such as sorting data type and data width in number of bits, discarding element position inside the sorting array, compile and runtime reconfigurable sorter depth, sorting direction, control and status register access bus, etc. Various generator instances have been mapped onto a commercially available FPGA platform, tested and mutually compared. It is proven that such a generator can yield resource and performance competitive sorter designs.
A cloud-based platform for the non-invasive management of coronary artery disease
(2020) Sakellarios, Antonis; Correia J.; Kyriakidis S.; Georga E.; Tachos N.; Siogkas, Panagiotis; Sans F.; Stofella P.; Massimiliano V.; Clemente, Alberto; Rocchiccioli S.; Pelosi, Gualtiero; Filipovic, Nenad; Fotiadis D.
© 2020 Informa UK Limited, trading as Taylor & Francis Group. We present the architecture and the usability testing of a novel cloud-based platform, which integrates cyber-physical systems and interoperability standards enabling a clinical decision support system for risk stratification, diagnosis, prognosis and treatment of CAD. In this work multi-disciplinary human data were used for the development of machine learning and computational biomechanics based predictive models. Two Lab-on-Chip devices have been integrated into the cloud platform. A targeted RNA-panel provides the mRNA gene expression values for the stratification algorithm. The results of the usability testing demonstrate that the platform is efficient, accurate and performs all developed tasks quickly.
A cloud-based with microcontroller platforms system designed to educate students within digitalization and the industry 4.0 paradigm
(2021) Mijailović Ð.; Ðorđdević A.; Stefanovic, Miladin; Vidojević D.; Gazizulina, Albina; Projovic D.
The primary purpose of this paper is to present a system intended for student education based on a microcontroller platform and a cloud system where data will be stored. Obtained research results will be based on the application of The NodeMcu platform for data collection with sensor systems. MatLab, ThingSpeak cloud system, and the Virtuino platform will be used for data presentation. Quantitative data are applied to determine conditions for agriculture system performance management. By analyzing the literature and the current situation in monitoring and managing in the agriculture and ecology field, it can be concluded that there are no special education courses regarding these issues. This knowledge was a good starting point for the research presented in this paper. Accordingly, the findings include developing a monitoring and management system intended for student education in mentioned fields. In addition, the practical implications of this research includes the acquisition of information related to student satisfaction with this method of education in the courses of engineering, agriculture, and ecology. The presented system may enable benchmarking, simulation, and verification of different scenarios to improve students’ knowledge regarding sensors’ application in natural conditions. The originality of the research lies in the presented software solution that can be made available to educational institutions and other scientific institutions to serve as a basis in the overall monitoring and management of agricultural and ecology parameters.
A comparison of classifiers in biomedical signal processing as a decision support system in disc hernia diagnosis
(2020) Sustersic, Tijana; Milovanović, Vladimir; Rankovic, Vesna; Filipovic, Nenad
© 2020 Elsevier Ltd The aim of this research was to investigate the best methodology for disc hernia diagnosis using foot force measurements from the designed platform. Based on the subjective neurological examination that examines muscle weakness on the nerve endings of the skin area on feet and concludes about origins of nerve roots between spine discs, a platform for objective recordings of the aforementioned muscle weakness has been designed. The dataset included 33 patients with pre-diagnosed L4/L5 and L5/S1 disc hernia on the left or the right side, confirmed with the MRI scanning and neurological exam. We have implemented 5 different classifiers that were found to be the most suitable for smaller dataset and investigated the accuracy of classification depending on the normalization method, linearity/non-linearity of the algorithm, and dataset splitting variation (32–1, 31–2, 30–3, 29-4 patients for training and testing, respectively). The classifier is able to distinguish between four different diagnoses L4/L5 on the left side, L4/L5 on the right side, L5/S1 on the left side and L5/S1 on the right side, as well as to recognize healthy subjects (without disc herniation). The results show that non-linear algorithms achieved better accuracy in comparison to tested linear classifiers, suggesting the expected non-linear connection between the foot force values and the level of disc herniation. Two algorithms with highest accuracy turned out to be Decision Tree and Naïve Bayes, depending on the normalization method. The system is also able to record and recognize improvements in muscle weakness after surgical operation and physical therapy.
A Comparison Study of Fatigue Behavior of S355J2+N, S690QL and X37CrMoV5-1 Steel
(2022) Milovanović, Vladimir; Arsić, Dušan; Milutinović, Milan; Zivkovic, Miroslav; Topalović, Marko
Steel of the mild-strength S355J2+N steel grade is the most often used steel for manufacturing carrying sections of constructions exposed to fatigue loads. The use of high-strength steels, such as S690QL, allows for the creation of structures that are light and simple to construct. However, increasing the yield strength of high-strength steels does not result in a corresponding increase in fatigue resistance. As a result, using high-strength steels for constructions subjected to fatigue loading can be a major design concern, raising the question of whether high-strength steels should be used at all. Most of the experimental investigations regarding the hot work tool steel X37CrMoV5-1 found in the literature are focused on its machining and wear resistance, with insufficient attention paid to the cyclic loads. This article evaluates the fatigue properties of mild-strength S355J2+N, high-strength S690QL, and X37CrMoV5-1 steel grades. A SHIMADZU servo-hydraulic testing machine is used to perform uniaxial tensile tests under uniaxial fatigue stress-controlled, fully reversed conditions (tensile–compression testing with R = −1 stress ratio) in accordance with EN ISO and ASTM standards. The aim of this paper is to highlight the fatigue characteristics of these three steels that are among the most used in their respective groups. Steel S355J2+N belongs to the group of hot-rolled normalized steels, S690QL belongs to the group of improved (quenched + tempered) steels with increased strength, and X37CrMoV5-1 belongs to the group of high-alloyed tool steels for hot work. This choice was made as the tested steels can be considered typical representatives of their groups. Based on the test results of these three steels, which are organized in S–N curves, the fatigue behavior of the entire mentioned groups of steels can be foreseen.
A comprehensive study into the boltless connections of racking systems
(2020) Vujanac, Rodoljub; Miloradović, Nenad; Vulovic, Snezana; Pavlović A.
© 2020 by the authors. Licensee MDPI, Basel, Switzerland. In practice, structures of pallet racks are characterized by very wide options of beam-to-column connections. The up to date part of the standard Eurocode 3 considers details for the design of connections. However, experimental determination of the joint properties in steel pallet racks is the most reliable process, since it takes into account an inability to develop a general analytical model for the design of these connections. In this paper, a test procedure for the behavior of beam-to-column connections is presented and the results are analyzed according to the procedure defined in the relevant design codes. With aim to avoid expensive experiments to determine structural properties of different types of connections, a polynomial model and a corresponding numerical model were developed to be used for simulating the experiment. After verification, the developed analytical and numerical model can be applied for investigation of various combinations of beam-to-column connections.
A computational study of trajectories of micro- and nano-particles with different shapes in flow through small channels
(2014) Isailovic V.; Kojić M.; Milosevic M.; Filipovic, Nenad; Kojić N.; Ziemys, Arturas; Ferrari M.
Transport of small particles, of micrometer and sub-micrometer size, by fluid occurs in many technological and biological systems. The channels through which the fluid flows are often with cross-sectional dimensions on the order of several to tens of micrometers. The aim of this study was to investigate effects of shape of micro- and nano-particles on particle trajectories when particles are transported within small channels as blood vessels. Efficiency of therapeutics by particles as the drug carriers is significantly dependent on particle trajectories. It is desirable to have particle trajectories approaching the vessel walls in order to increase therapeutic efficacy. We studied motion of particles in channels (pipes) for two physical conditions: Poiseuille flow, which is characteristic in pipe flow, and shear flow. Shear flow conditions are analyzed since the character of fluid flow near the wall in these systems can be approximated as shear, with a linear change of velocity with the distance from the wall. We here investigated trajectories of particles of different shapes in 2D flow using the finite element (FE) method, with a strong coupling approach for solid-fluid interaction and a remeshing procedure. The results give insight into the characteristics of the particle motion, e.g. trajectories and rotations, under various flow conditions in micron size channels, including flow in the presence of moving deformable discs. We demonstrate that the particle trajectories are essentially parallel to the wall for various conditions and that particle size and shape do not considerably alter the parallel nature of the trajectories.
A contribution to research of degradation of characteristics of vibration parameters on vibration aspect of vehicle comfort
(2012) Demić, Miroslav; Diligenski D.
Dynamic simulation, based on modeling, has a significant role in vehicle development, especially in the early stages of design process, when relevant parameters are being defined. In praxis it is usually assumed that vibration parameters are unchangeable, what is basically wrong. All researches indicate that vibration parameters degrade in time of vehicle service, consequently leading to a variation of its dynamic characteristics. This paper, based on preliminary research results, attempts to point out the necessity of taking into consideration this variation in the earliest phases of vehicle design by its implementation in the vehicle simulation model.
A contribution to research of the influence of degradation of vehicle vibration parameters on thermal load of shock absorbers
(2013) Demić, Miroslav; Diligenski D.; Milovanovic, Milan
Dynamic simulation, based on modelling, has a significant role during to the process of vehicle development. It is especially important in the first stages of vehicle design, when relevant parameters are to be defined. In practice, it is commonly assumed that vehicle vibration parameters are invariable, what is basically not true. Many investigations have shown that vibration parameters degrade in service conditions, what consquently leads to the variation of dynamic characteristics of a vehicle. This paper attempts to indicate, on the basis of the preliminary results, a need to introduce these variations, caused by the thermal impact, in the early stages of vehicle design through the adequate vehicle modelling.
A contribution to research of the influence of steering trapeze on bus steered wheels shimmy
(2013) Demić, Miroslav; Diligenski D.
Steered wheels shimmy is a harmful phenomenon in the steering system ofthe vehicle. It causes driver's fatigue and fatigue of the elements of steering system, increased tire wear etc. In practice, efforts are being made to reduce or eliminate the occurrence of this effect, and the buses are sometimes equipped with shock absorbers in the steering trapeze. In this paper an attempt is made to analyze the influence of shock absorber in the steering trapeze on the steered wheels shimmy of a bus. Analysis showed that shock absorbers significantly affect the reduction of steered wheels shimmy.
A contribution to research of vibrational loads of the vehicle steering system's tie-rod in characteristic exploitation conditions
(2012) Demić, Miroslav; Miloradović, Danijela; Glišović, Jasna
The paper presents and reviews the results of the analysis of vibrational loads of the steering system's tie-rod for passenger car in characteristic exploitation conditions. Experimental data are acquired using the left tie-rod's relative deformation sensor, vertical acceleration sensors at the centres of all four wheels, vertical acceleration sensor at the connecting point between the left front shock absorber and the vehicle body, longitudinal vehicle speed sensor, steering wheel angular displacement sensor and steering wheel torque sensor. Tests are performed during straight line drive and vehicle cornering, with constant and variable vehicle speed and on different types of the roads. On the basis of acquired experimental data, the influences of the inputs from the road roughness (type of the road), the steering wheel torque, the steering wheel angular displacements and vehicle speed on vibrational loads of the steering system's tie-rod loads are analyzed.
A critical review of biofuels as an alternative fuel to diesel in gulf regional corporation (gcc) region: Current market trends and future opportunitie
(2022) Mahroogi F.; narayan, s; Kaisan, Muhammad Usman; Aliyu A.; Yahuza I.; Grujic I.; Stojanovic, Nadica
Bio Fuels are considered as good alternatives for conventional fossil fuels. By the year 2020, in the GCC region these fuels are able to meet around 0.5 - 1 % of total transportation fuel demand. This industry grew at rate of 3.4 % over the period of 2015-2020 with a strong projected growth in the Kingdom of Saudi Arabia (KSA). Bio fuels are used to operate automotive for mining and construction industries. Critical barriers in foreign investments pose a major challenge for growth of this sector in the GCC region. The presented work discusses situation and growth predictions of Bio-Fuel industry in the GCC region. It also discusses about current growth, trends, opportunities and challenges being faced by major companies operating in the GCC region.
A Customizable DDR3 SDRAM Controller Tailored for FPGA-Based Data Buffering Inside Real-Time Range-Doppler Radar Signal Processing Back Ends
(2019) Milovanović, Vladimir; Tasovac D.
© 2019 IEEE. High resolution commercial radars which feature arrays of transmit and receive antennas and that rely on unambiguous range-Doppler signal processing with hard real-time constraints require fast memories to store intermediate results. Typical radar data matrices can occupy up to a gigabyte of space. A custom DRAM controller tailored for digital radar back ends and software-defined radars is presented. It is implemented on an FPGA and supports data buffering between the two FFT stages inside a two-dimensional spectral analysis system. In parallel, it allows the remaining part of the SDRAM to be used as a virtual FIFO buffer for the output results. Experimental tests have shown that when both pairs of the proposed memory controller's ports are accessed simultaneously, their joint data throughput is within 10% of the gross theoretical limit for the utilized DDR3 module.
A Deep Learning Model for Automatic Detection and Classification of Disc Herniation in Magnetic Resonance Images
(2022) Sustersic, Tijana; Rankovic, Vesna; Milovanović, Vladimir; Kovacevic, Vojin; Rasulić L.; Filipovic, Nenad
Localization of lumbar discs in magnetic resonance imaging (MRI) is a challenging task, due to a vast range of shape, size, number, and appearance of discs and vertebrae. Based on a review of the cutting-edge methods, the majority of applied techniques are either semi-automatic, extremely sensitive to change in parameters, or involve further modification of the results. All of the above represents a motivation for implementing deep learning-based approaches for automatic segmentation and classification of disc herniation in MR images. This paper proposes a complete automated process based on deep learning to diagnose disc herniation. The methodology includes several steps starting from segmentation of region of interest (ROI), in this case disc area, bounding box cropping and enhancement of ROI, after which the image is classified based on convolutional neural network (CNN) into adequate classes (healthy, bulge, central, right or left herniation for axial view and healthy, L4/L5, L5/S1 level of herniation in sagittal view). The results show high accuracy of segmentation for both axial view (dice = 0.961, IOU = 0.925) and sagittal view (dice = 0.897, IOU = 0.813) images. After cropping and enhancing the region of interest, accuracy of classification was 0.87 for axial view images and 0.91 for sagittal view images. Comparison with the literature shows that proposed methodology outperforms state-of-the-art results when it comes to multiclassification problems. A fully automated decision support system for disc hernia diagnosis can assist in generating diagnostic findings in a timely manner, while human mistakes caused by cognitive overload and procedure-related errors can be reduced.

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