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Characterization of Model Uncertainty Features Relevant to Model Predictive Control of Lateral Vehicle Dynamics

Gabor Rodonyi Dániel Pup Ádám Kisari Zsombor Vigh Alexandros Soumelidis József Bokor

Publication Name: 2020 23rd IEEE International Symposium on Measurement and Control in Robotics Ismcr 2020

Publication Date: 2020-10-15

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

The information about a system's dynamics represented by measurement data sets are often confined to regions of restricted operations where the system is not sufficiently excited for model identification purposes. Experiments performed in closed-loop with safety constraints allow only for reduced order modeling. In the paper, a set of low order models are identified from real experimental data of the lateral dynamics of an electric passenger car. Low order models are advantageous for on-line computation in model-based control, though uncertainty due to neglected dynamics may deteriorate control performance and constraint satisfaction. The effect of uncertainty is analyzed by controller cross-validation where a controller designed based on one model is evaluated on other models playing the role of the true system. This method allows us to qualify not only model-controller pairs, but to determine the properties of input data and model uncertainty, which lead to more useful data sets, more robust and better performing controllers than the others.

Open Access: Yes

DOI: 10.1109/ISMCR51255.2020.9263745

Comparison of High-Precision GNSS systems for development of an autonomous localization system

Huba Somogyi Alexandros Soumelidis

Publication Name: 2020 23rd IEEE International Symposium on Measurement and Control in Robotics Ismcr 2020

Publication Date: 2020-10-15

Volume: Unknown

Issue: Unknown

Page Range: Unknown

Description:

In the near future, the vehicles offering advanced driver assistance or fully autonomous operation. It will require increasingly accurate position information, available in all driving conditions and with 100 percent availability. In generally, a single sensor cannot meet these requirements alone and so it is necessary to use a combined sensor suite solution incorporating different kinds of sensors working together. As the only source of absolute position, velocity and time, Global Navigation Satellite systems (GNSS) play a critical role in next generation positioning systems. In this paper, we are dealing with modern GNSS solutions and presents the results of the comparison of two high-precision GNSS systems in different driving conditions and presents conclusion for the develop of autonomous localization system.

Open Access: Yes

DOI: 10.1109/ISMCR51255.2020.9263762

Experimental analysis and numerical modelling of contact damping

Balázs Pere B. Magyar R. Wohlfart R. Zana G. Stépán G. Csernák

Publication Name: Journal of Sound and Vibration

Publication Date: 2020-10-13

Volume: 484

Issue: Unknown

Page Range: Unknown

Description:

The energy dissipation in assembled metal structures is mainly related to various physical phenomena – usually modelled as dry friction – on the contact surfaces. However, the reliable numerical modelling of assemblies is a challenging task due to the complexity of the contact mechanisms. To fit the models to experimental results, it is beneficial if the material damping can be separated from the contact damping. The paper presents measurement results aiming to distinguish material damping from the damping related to the contact between the conforming surfaces of assembled machine parts. To evaluate the role of contact in damping and to find a connection between the contact-related increase of modal damping and the mode shapes, the modal damping ratios of a monolithic body and a shrink-fitted assembly are compared. It is demonstrated that the contact damping is linear in the examined case. Based on the experiments, a finite element (FE) model was developed that does not apply computationally expensive contact algorithms. The FE model was able to reproduce the measured modal damping values of the assembled structure at all the natural frequencies that fell in the frequency range of the measurement. This result is achieved by fitting only a single damping parameter. The research work is motivated by metal cutting, where the damping of the machine-tool-workpiece loop plays a key role in the stability of the process, particularly in case of high speed machining.

Open Access: Yes

DOI: 10.1016/j.jsv.2020.115544

Multiple-solution heat exchanger network synthesis for enabling the best industrial implementation

Ákos Orosz Ferenc Friedler

Publication Name: Energy

Publication Date: 2020-10-01

Volume: 208

Issue: Unknown

Page Range: Unknown

Description:

The synthesis of heat recovery networks traditionally results in an optimal or suboptimal solution for the supplied set of streams and simplifying assumptions. In the current work, the assumption of a single optimal solution is replaced by the goal of generating an ordered set of optimal or quasi-optimal networks. This enables industrial engineers to further select the solution most suitable for detailed design and practical implementation. The problem is formulated for and solved by an extension of the P-graph framework for combinatorial process network optimization. The presented method for HEN synthesis generates a list of solutions ranked by the Total Annualized Cost. In addition to the feasibility, all list elements also feature a degree of heat recovery ranging from the thermodynamic maximum, down to a specified margin allowing accounting for the energy-capital trade-off. The current method is illustrated with three case studies. The obtained results demonstrate optimal solutions that cannot be generated by the Pinch-based methods or the stage-wise superstructure approaches. The proposed parameters, an upper limit on the number of heat exchangers per process stream and a maximum relaxation of utility demand compared to the Pinch targets, allow performing parametric evaluations of the resulting solutions.

Open Access: Yes

DOI: 10.1016/j.energy.2020.118330

Lifestyle changes during Covid-19 period in Hungary–feedback of university students

Gyöngyvér Lacza Miklós Bánhidi

Publication Name: World Leisure Journal

Publication Date: 2020-10-01

Volume: 62

Issue: 4

Page Range: 325-330

Description:

Our study aimed to investigate the immediate impact of coronavirus on lifestyle changes among Hungarian students from leisure studies living in western part of Hungary. The study comprised an analysis of written reports by the trials focusing on the main lifestyle elements, such as biological needs, social duties and leisure. The respondents stated that the biggest change with them was to take hygienic requirements more seriously (47%), or paying more attention to have organized meals (25.5%). Despite our expectations, for 75.2% of the trials, it was important to study more, but also every third student (31.4%) had to do more physical work to earn money for their studies. Students wrote about suffering from the lack of entertainment businesses due to the lockdown. Instead of going out, they found it very important to do more sports (mainly workout 67.2%) and use virtual entertainment such as watching videos (47.4%) and reading books (44.5%).

Open Access: Yes

DOI: 10.1080/16078055.2020.1825251

The regional and geographical aspects of food security: A spatial analysis in the case of Azerbaijan, Hungary, Austria, Singapore and Georgia

Laszlo Vasa Lóránt Dávid Imre Varga Ragif Huseynov

Publication Name: Geographia Technica

Publication Date: 2020-10-01

Volume: 15

Issue: 2

Page Range: 161-170

Description:

Achieving food security is crucial, and a primary development goal world-wide. However, there is a difficulty in finding reliable data on the topic, which raised a problem for policymakers and researchers as well. Therefore, the present study aimed to fill in this gap by examining the dynamics of regional food security. The main research objective was to identify the determinants of food security in Azerbaijan, Singapore, Austria, Georgia and Hungary. Furthermore, a specific objective was to investigate the short- and long-term impacts of both endogenous and exogenous shocks on the food security of the selected countries. The study collected large scale panel dataset between 1992 and 2019. The empirical model suggested that food import, foreign direct investment, inflation, annual per capita income and Human Development Index had a positive, while the flow of food export had an adverse impact on the food security status of the selected countries. The study recommended to the governments of selected countries and to developmental organisations to achieve national food security through indigenous agricultural interventions along with supporting domestic growers by investing in agricultural education, skill development and infrastructure programs.

Open Access: Yes

DOI: 10.21163/GT_2020.152.16

Extended Solution of a Trimmed Vehicle Finite Element Model in the Mid-Frequency Range

Dániel Feszty Jonathan Jacqmot Antoine Guellec Markus Brandstetter David Sipos

Publication Name: SAE Technical Papers

Publication Date: 2020-09-30

Volume: Unknown

Issue: 2020

Page Range: Unknown

Description:

The acoustic trim components play an essential role in Noise, Vibration and Harshness (NVH) behavior by reducing both the structure borne and airborne noise transmission while participating to the absorption inside the car and the damping of the structure. Over the past years, the interest for numerical solutions to predict the noise including trim effects in mid-frequency range has grown, leading to the development of dedicated CAE tools. Finite Element (FE) models are an established method to analyze NVH problems. FE analysis is a robust and versatile approach that can be used for a large number of applications, like noise prediction inside and outside the vehicle due to different sources or pass-by noise simulation. Typically, results feature high quality correlations. However, future challenges, such as electric motorized vehicles, with changes of the motor noise spectrum, will require an extension of the existing approaches. In this paper, the vibro-acoustic frequency response of an existing MSC Nastran FE model is extended using the Actran Statistical Energy Analysis (SEA) approach, Virtual SEA. In Virtual SEA, the necessary information required to build the SEA system is extracted from the FE models. The fluid-structure Coupling Loss Factors (CLF) are computed through the Statistical modal Energy distribution Analysis (SmEdA) method. This method is a suitable candidate to account for acoustic trim effects based on analytical approach. The case studied consists of a trimmed body car model transfer function calculation. The result of the case study is an extensive correlation study containing measured and simulated transfer functions in low and mid-frequency range. Simulation results are derived from two approaches, FE method and Virtual SEA method.

Open Access: Yes

DOI: 10.4271/2020-01-1549

Measuring colour afterimage perception

Lorinc Garai András Horváth

Publication Name: 11th IEEE International Conference on Cognitive Infocommunications Coginfocom 2020 Proceedings

Publication Date: 2020-09-23

Volume: Unknown

Issue: Unknown

Page Range: 191-196

Description:

Afterimages are common and frequent perceptual phenomena of everyday life. When looking into a high-intensity light source and suddenly turning away from it, a temporary 'ghost' of the light source remains in perception, for a while. A highly saturated, coloured incident light has a different effect on the three types of cone cells. Therefore, the fast change in the colour of incident light triggers different intensity afterimage on the different types of cones, and the observer perceives a colour afterimage disappearing in a between 10- and 100-second timescale. By choosing incident light colours, colour afterimages can be applied in visual design, like in modern, dynamic advertising. Our previous work describes simulation of colour afterimages triggered by given colour combinations. For the validation of simulation, preliminary tests were performed with 20 subjects. Test results suggested the possibility of age dependence of intensity and duration of colour afterimages. In this work, we present the experimental results of 28 observers with different ages and gender. The disappearing time and perceived initial 'intensity' of the colour afterimages were measured in nine fast colour transition cases.

Open Access: Yes

DOI: 10.1109/CogInfoCom50765.2020.9237851

In the footsteps of Artificial Intelligence : EExamining logical relationships between employee turnover and behavior patterns

Bernadett Domokos Zoltán Baracskai

Publication Name: 11th IEEE International Conference on Cognitive Infocommunications Coginfocom 2020 Proceedings

Publication Date: 2020-09-23

Volume: Unknown

Issue: Unknown

Page Range: 569-572

Description:

In this study, the initial problem is the capacity of the human mind to set up a conceptual model. The novelty of this article is that we show that defined concepts created by the human mind can be passed on to an artificial intelligence-based expert system. The expert system helps the human mind to settle the logical connections between the defined terms and the conceptual model thus the created model will be better than what man could have set up without an expert system. These articles have examined the impact of employee turnover in countless aspects as one of potential index of a corporation. As a starting point for our research, we systematically reviewed the literature on employee turnover and selected six concepts that are bilaterally related to our phenomenon. Based on the terms and the correlation of it, we created a conceptual model that was examined with the help of an artificial intelligence-based system. Based on our experience in observing, consulting, and working with decision-makers, we examined the aspects of employee turnover phenomenon in the analysis. This was performed using a rule-based system, which used logical rules and found classical 'if-then' connections in the employee behavior cases. According to our examination, our outcomes can provide credible results for further research activities as well as for practitioners.

Open Access: Yes

DOI: 10.1109/CogInfoCom50765.2020.9237862