Acta Technica Jaurinensis

Acta Technica Jaurinensis

Basic info

  • Publisher: Szechenyi Istvan University
  • Country of publisher: hungary
  • Platform/Host/Aggregator: Open journal system ojs
  • Date added to EuroPub: 2019/Sep/29

Subject and more

  • LCC Subject Category: Engineering, Multidisciplinary
  • Publisher's keywords: Engineering, Multidisciplinary
  • Language of fulltext: english
  • Time from submission to publication: 14 weeks

Publication charges

  • Article Processing Charges (APCs): No
  • Submission charges: No
  • Waiver policy for charges? No

Open access & licensing

  • Type of License: CC BY-NC
  • License terms
  • Open Access Statement: Yes
  • Year open access content began: 2008
  • Does the author retain unrestricted copyright? True
  • Does the author retain publishing rights? True

Best practice polices

  • Permanent article identifier: DOI
  • Content digitally archived in: Electronic Periodicals Archive of the National Széchényi Library (Budapest, Hungary)
  • Deposit policy registered in: None

This journal has '91' articles

Comparative Evaluation of Sighted and Visually Impaired Subjects using a Mobile Application for Reducing Veering during Blindfolded Walking

Comparative Evaluation of Sighted and Visually Impaired Subjects using a Mobile Application for Reducing Veering during Blindfolded Walking

Authors: H. Nagy, G. Wersényi
Year: 2016, Volume: 9, Number: 2
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Abstract

Measurements were conducted using a navigational application on an Android Smartphone that provides auditory and haptic feedback based on electromagnetic sensor data (compass) in order to help users walk in a straight line. Blindfolded sighted subjects attempted to walk along a 40-meter path with and without navigational assistance. Results showed that optimal settings of accuracy, sensitivity and target direction on the device can significantly reduce veering. Further, it was shown that even a short training session consisting of four trials could lead to better subsequent performance without navigational assistance.

Keywords: mobile device, veering, blind user, acoustic feedback
Advanced Modelling of Virtualized Servers

Advanced Modelling of Virtualized Servers

Authors: Á. Kovács, G. Lencse
Year: 2016, Volume: 9, Number: 2
(0 downloads)
Abstract

In the recent years, server virtualization is one of the most important directions of IT infrastructure development. Simulating virtualized infrastructures are unavoidable for designing cloud systems that are customized perfectly for a company. In this paper, we used Opennebula, Haizea and some other tools under public licenses to experiment with. We executed several experiments to examine measurement and simulation capabilities of Haizea and we also tested some typical cluster compilations from the point of view of usability and power consumption. We also tested an open source high availability web server that used virtual machines as computing resource.

Keywords: simulation, Opennebula, Haizea, Cloud Computing, consumption
Earthquake Risk Assessment – Effect of a Seismic Event in a Moderate Seismic Area

Earthquake Risk Assessment – Effect of a Seismic Event in a Moderate Seismic Area

Authors: O. Kegyes-Brassai, R. Ray
Year: 2016, Volume: 9, Number: 1
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Abstract

This paper presents the process of earthquake risk analysis from the probabilistic determination of seismic hazard and local site effects, through the evaluation of building vulnerability to an event resulting in seismic risk maps. These results can then serve as useful tools for decision makers and insurance companies, and can be applied directly to overall risk management plans of cities. Finally a case study for seismic risk assessment performed in city of Győr is presented, taking into account local site effects based on response analysis with more than 6000 realizations and rapid visual screening of 5000 building to obtain the seismic risk.

Keywords: earthquake hazard, local site effect, vulnerability, risk assessment
A Method for the Numerical Modelling of Embedded Rails and Determining Parameters to be Optimized

A Method for the Numerical Modelling of Embedded Rails and Determining Parameters to be Optimized

Authors: Z. Major
Year: 2016, Volume: 9, Number: 1
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Abstract

To carry out FEM modelling two model parameters are needed the elastic (Young) modulus (E) and the Poisson-coefficient (μ). Unfortunately, they are not available in every case, and even if so, they need to be corrected. The author’s earlier examinations have shown that FEM models are extremely sensitive to the value of the Poisson-coefficient. A very small change in them causes a significant difference in determining the elastic coefficient of the rail support. Literature deals with the factors determining the elastic characteristics of embedded rails. In practice the details for the spring constant on a given geometry test specimen (D) and Shore-A hardness (ShA) are available. These details can’t be directly used to create the model but they are suitable to determine parameters that are close to the real values.

Keywords: embedded rail, material properties of pouring material, optimalisation of ERS
Special Thermal Insulation Methods of Building Constructions with Nanomaterials

Special Thermal Insulation Methods of Building Constructions with Nanomaterials

Authors: D. Bozsaky
Year: 2016, Volume: 9, Number: 1
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Abstract

Nanotechnology-based materials have previously been used by space research, pharmaceuticals and electronics, but in the last decade several nanotechnology-based thermal insulation materials have appeared in the building industry. Nowadays they only feature in a narrow range of practice, but they offer many potential applications. These options are unknown for the most architects, who may simply be afraid of these materials owing to the incomplete and often contradictory special literature. Therefore, they are distrustful and prefer to apply the usual and conventional technologies. This article is intended to provide basic information about nanotechnology-based thermal insulation materials for designers. It describes their most important material properties, functional principles, applications and potential usage options in building construction.

Keywords: nanotechnology, thermal insulation, building construction
Determination of Load for Quasi-static Calculations of Railway Track Stress-strain State

Determination of Load for Quasi-static Calculations of Railway Track Stress-strain State

Authors: D. Kurhan
Year: 2016, Volume: 9, Number: 1
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Abstract

When calculating the railway track stress-strain state one usually assumes that total strains are brought immediately from applied load and the process dynamics is taken into account by the respective levels of design force. The dynamic component of the design force depends on various factors that are not always taken into account to the full. The analytical analysis of the calculation methods and the experiment testing data resulted in the following recommendations: for freight trains, especially in the conditions of soft rail support, it is advisable to take into account the effect of adjacent wheels; for modern passenger cars there is no significant load dependence on speed, and the main factor of dynamic component is the track fluctuations.

Keywords: railway, permanent way, dynamic load, track stress-strain state
Measuring the Efficiency of Parallel Discrete Event Simulation in Heterogeneous Execution Environments

Measuring the Efficiency of Parallel Discrete Event Simulation in Heterogeneous Execution Environments

Authors: G. Lencse, I. Derka
Year: 2016, Volume: 9, Number: 1
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Abstract

This paper deals with the experimental testing and verification of the earlier proposed load balancing and coupling factor criteria for the conservative parallel discrete event simulation in heterogeneous execution environments whether they can ensure a good speedup. The definition of the relative speedup is extended to the heterogeneous systems in a natural way. This definition is used to measure the efficiency of the parallel simulation executed by heterogeneous systems. A closed queueing network is used as the simulation model. It is demonstrated on the example of a heterogeneous system containing 134 CPU cores of 6 different types of computers that a good speedup can be achieved using the load balancing and coupling factor criteria. It is shown that the extension of the definition of the relative speedup to the heterogeneous systems made it easy to judge the speedup of parallel discrete event simulation in heterogeneous execution environments.

Keywords: parallel discrete event simulation, heterogeneous execution environment, conservative synchronisation method, load balancing criterion, coupling factor criterion
Spectral Reconstruction with Genetic Optimization in Case of Different Sample Sets

Spectral Reconstruction with Genetic Optimization in Case of Different Sample Sets

Authors: Zs. Sávoli, A. Horváth, B. Kránicz
Year: 2016, Volume: 9, Number: 1
(0 downloads)
Abstract

Finding the spectral features of color sample sets is a main issue of colorimetry. It is widespread to apply Principal Component Analysis in these researches. Several studies were written about the reconstruction of samples with known spectra using principal components, and some works dealt with approximate reconstruction from tristimulus values. Our study examines how spectral reconstruction done with genetic optimization works in case of different sample sets. We have taken only the tristimulus values of the color samples given.

Keywords: spectral reconstruction, tristimulus values, principal component analysis, genetic optimization, different samle sets
Preprocessing Endoscopic Images of Colorectal Polyps

Preprocessing Endoscopic Images of Colorectal Polyps

Authors: A. Horváth, S. Spindler, M. Szalay, I. Rácz
Year: 2016, Volume: 9, Number: 1
(0 downloads)
Abstract

Classification of polyps in the human colorectum is a hot topic of gastroenterology. The current advancements in devices of endoscopy made it possible to product high resolution images of polyps with different light filters, e.g. with narrow band imaging (NBI) system. There exists several human classification methods that helps the doctor to decide whether a specific polyp is risky (i.e. it can be turn into cancer) or not. To overcome the limits of human classification skill, a digital image processing method was developed by the authors of this paper. This paper summarizes the preprocessing method of this software, which is not a trivial task, because during the inspection of a patient, the diagnostician has limited control of light and geometry. Therefore the surface of the polyp is not uniformly illuminated, and prominent flares could appear on the images quite often. These circumstances makes it hard to detect the surface patterns precisely. In this paper a lot of variants for this preprocessing task is presented. The best of them appears to reproduce the geometrical parameters of the patterns in 1--5\% relative error which is enough for the classification method. The proposed method can be applied to another problems, where the precise measurement of patterns in highly variable illuminating conditions is needed.

Keywords: image processing, thresholding, illumination
Dynamic Analysis of a One-cylinder Engine Crankshaft

Dynamic Analysis of a One-cylinder Engine Crankshaft

Authors: P. Horváth, J. Égert
Year: 2015, Volume: 8, Number: 4
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Abstract

The article deals with the vibration analysis of a one-cylinder engine crankshaft. For the analysis, a sequential torsional multi-mass vibration model was created of the crank-mechanism. The natural frequencies and natural modes of the crankshaft were determined from this model. The results of the torsional model were verified with a 3D finite element model, which consists of not only the torsional, but every other natural frequency and mode of the crankshaft. From the torsional natural frequencies and the harmonic expansion of the excitation forces, the critical speeds were determined, where resonance phenomena can occur. The relative angular deflection of the two ends of the crankshaft was also determined which characterizes the torsional stiffness of the crankshaft. From the angular velocity function of the clutch, the measure of speed irregularity of the clutch was defined.

Keywords: crankshaft, multi-mass model, vibration, natural frequency, natural mode
FEM Modeling and Weight Reduction of a Solar Energy Driven Racing Car Chassis

FEM Modeling and Weight Reduction of a Solar Energy Driven Racing Car Chassis

Authors: L. Fehér, J. Égert
Year: 2015, Volume: 8, Number: 4
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Abstract

The paper demonstrates the strength analysis of a solar energy driven racing car chassis with two different mechanical modeling, beam-bar and shell modeling. Weight reduction is also a key point in the stages of car design. Reducing the weight of the car results in higher fuel efficiency and usually better dynamical properties. The weight reduction was performed with three different materials, steel, aluminium-alloy and laminated fibre reinforced composites. The paper shows the complete mechanical modeling process from construction of the mechanical model to the analysis of the laminated composite chassis structure and the results of the weight reduction.

Keywords: car chassis, steel, aluminium-alloy, fibre reinforced composite, strength analysis, FEM, weight reduction
Finite Element Analysis of Glass Vacuum Windows of the “COMPASS” Tokamak in Prague

Finite Element Analysis of Glass Vacuum Windows of the “COMPASS” Tokamak in Prague

Authors: Z. Molnár, J. Égert, M. Berta
Year: 2015, Volume: 8, Number: 4
(0 downloads)
Abstract

In this paper is described the mechanical stress analysis of glass vacuum windows of the "COMPASS"  tokamak using Finite Element Method. As a reference test problem the problem of uniformly loaded glass vacuum window with circular shape has been chosen, which problem can be solved also analytically.  In the case of Finite Element analysis we used two different mechanical models: 3-dimensional (3D) approach and shell modelling. For 3D approach an optimal finite element type - quadratic tetrahedron element with appropriate size - was chosen, and for shell modelling a thin axisymmetric shell element type - shell 209 - was applied. The analytic and both numerical results have been compared and summarized.

Keywords: stress analysis, Finite Element Method (FEM), glass vacuum windows, the “COMPASS” tokamak, shell element, deformation, equivalent (von Mises) stress
Upgrading Multilevel Full Cost Allocation: Case Transport

Upgrading Multilevel Full Cost Allocation: Case Transport

Authors: Z. Bokor, B. Horvath
Year: 2015, Volume: 8, Number: 4
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Abstract

Multilevel full cost allocation is an effective alternative of traditional, accounting oriented costing regimes and is applied in the transport sector as well. Nevertheless, its basic algorithm may fail when the cost calculation model contains so called performance feedbacks. This is often the case in transport management practice, especially in complex operational systems. Hence effective solutions are to be found to cope with this methodological problem. This paper aims at contributing to the improvement of multilevel full cost allocation method when performance feedbacks hinder the exact calculation. The application of estimated cost ratios or specific costs is proposed and tested on a theoretical transport costing example. If some methodological requirements can be met both parameter estimations may be employed effectively in calculation tasks with performance feedbacks.

Keywords: multilevel full cost allocation, performance feedbacks, transport costing
Measurement and Analysis of Deformation Shapes on Corrugated Cardboard Logistical Boxes Under Static and Dynamic Compression

Measurement and Analysis of Deformation Shapes on Corrugated Cardboard Logistical Boxes Under Static and Dynamic Compression

Authors: P. Böröcz
Year: 2015, Volume: 8, Number: 4
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Abstract

On the field of compression strength of packaging the researchers, studies and standards mainly focus on the short-time measurements. The derived results from these accelerated tests can be used with a large tolerance in reality. These measurements do not give response that how long the packaging is able to tolerate the given calculated or measured stress during a long-term storage in the supply chain without damages in the aspect of product or packaging. The tests in this paper were done to analyse the possible deformation shapes, which could be a first step into the process of final damage. The samples were tested under both static and dynamic compression. The deformations were observed by TRITOP system in order to prove the different deformation processes between the static and dynamic compression. This paper is a first phase of a research program, which deals with the effect of real compression and physical environment of logistics boxes on long time storage and stacking.

Keywords: packaging, compression test, TRITOP
Overview of the Finite Element Method

Overview of the Finite Element Method

Authors: M. Kuczmann
Year: 2015, Volume: 8, Number: 4
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Abstract

By using scalar and vector potentials, Maxwell's equations can be transformed intopartial differential equations. Generally, the partial differential equations can be solved by numerical methods. One of these numerical methods is the finite element method, which is based on the weak formulation of the partial differential equations. The basis of numerical techniques is to reduce the partial differential equations to algebraic ones whosesolution gives an approximation of the unknown potentials and electromagnetic field quantities. This reduction can be done by discretizing the partial differential equations in time if necessary and in space. The potential functions, the approximation method and the generated mesh distinguish the numerical field solvers. This paper summarize the finite element method as a CAD technique in electrical engineering to obtain the electromagnetic field quantities in the case of static magnetic field and eddy current field problems. Here, we show how to discretize the analyzed domain with finite elements, how to approximate potential functions with nodal and vector shape functions and how to build up the system of equations, which solution obtain the unknown potentials.

Keywords: Maxwell’s equations, weak formulation, finite element method

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