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Optimizing timing for emergency vehicle approaching warnings
Get PDFEmergency driving is a demanding task. The ITS service Emergency Vehicle Approaching provides drivers with an in-car warning that an emergency vehicle is approaching. To ensure that the warning is efficient and reliable it must have a suitable timing. The EVA warning must be presented early enough to allow the driver to make a safe move-over maneuver. However, the distribution of EVA warnings is based on the most probable path of the emergency vehicle. If an EVA warning is distributed too early, it increases the risk of false alarms. In addition, if a warning is given too early the driver might deem it as irrelevant.Previous studies have distributed EVA warnings based on the distance between the emergency vehicle and surrounding cars. However, if the speed of the vehicle is not accounted for there is a risk of insufficient time for the driver to prepare for the emergency vehicle interaction. To explore suitable EVA timing, post-survey data from five driving simulator studies where drivers were exposed to EVA warnings were analyzed. The results suggest that 15–20 seconds could be an appropriate EVA timing. However, the required time for a move-over maneuver depends on the complexity of the current traffic situation
Nanomechanical properties of neutron-irradiated concrete
Get PDFConcrete exposed to irradiation from nuclear reactor undergoes atomic-level degradation due to the influence of neutrons, secondary gamma rays, and associated gamma heating. The radiationinduced damage decreases the mechanical properties of the concrete and affects its performance as a construction material. The concrete samples analysed in this work were prepared from blended Portland cement CEM II 32.5R mixed with siliceous aggregates with a size of 0–2.5 mm. The material underwent irradiation in the LVR-15 research reactor in Research Centre Rež to the target neutron fluence of 1.6–1.8 · 1019 n cm−2 (E>0.1MeV) and received the gamma dose of ⁓ 500 MGy. The temperatures during irradiation were kept within a range of 50–60 °C. The mechanical properties of the individual phases in the cementitious matrix after neutron irradiation were assessed by the nanoindentation. To track the evolution of the nanomechanical properties of individual components under radiation, a comparison was made between the mechanical properties of neutron-irradiated material and pristine concrete
Experimental of verification of alternative hydraulic binders flexural and compressive strength
Get PDFThe paper deals with the investigation of alternative binders, namely the two available samples N6 and N7 with comparison from the reference sample CEM I 42.5R. Both testing binders are provided by company Destro. It is a product that contains different ratios of fly ash and slag. By examining the properties, the mix was compared in different proportions and subsequently tested for flexural strength and compressive strength. The results showed the effect of curing time and cement to binder ratio after 28 and 84 days
An examination of driving speed: the role of perceivable road characteristics in towns
Get PDFUnderstanding the subjective perspectives of drivers is paramount in evaluating the factors affecting driving speed in built-up areas. Building on our previous work, where a wide set of infrastructure attributes was analysed, this paper delves deeper into the realm of driver perception. It seeks to answer how drivers’ observations and awareness of their surroundings influence their speed choices.We reconduct our previous analysis, emphasizing the driver’s subjective viewpoint, contemplating the visible and perceivable elements of the road infrastructure rather than their objective presence.This research aims to garner insights into how these subjective elements impact speed choices. This research has uncovered a number of interesting factors that have not been previously used in the calculation of road vehicle speeds. This more nuanced understanding is expected to lead to enhanced safety and efficiency in road traffic management, ensuring the road design aligns seamlessly with driver perception and behaviour
Assessing time and financial costs of bus delays in the Ústí nad Labem Region, Czech Republic
Get PDFThis publication focuses on the development of a regional system for monitoring and evaluating public bus delays in the Ústí nad Labem Region in the Czech Republic.The case study, through a questionnaire survey, addresses the issue of the value of time loss caused by delays in regional public bus transport in the Ústí nad Labem Region from both a societal and individual passenger perspective. The survey includes, in addition to opportunity costs, the necessity to use earlier buses due to uncertainty and the potential real financial loss of passengers, for instance, due to late arrival to work and p otential employer sanctions. Routes for the questionnaire survey were selected based on an analysis of the movement of the bus fleet to represent typical situations applicable to the entire bus transport network.The result is a financial evaluation of the losses caused by bus delays in relation to the number of passengers, the purpose of their journeys, and the value of their time. The findings reveal relatively high costs of time losses, which, when applying a co st benefit approach, allow for the return on larger infrastructure investments aimed at reducing these delays. The research results will contribute to the development of issues evaluating the economic efficiency of investments in transport infrastructure
so(3) ⊂ su(3) revisited
Get PDFThis paper reproduces the result of Elliot, namely that the irreducible finite dimensional representation of the Lie algebra su(3) of highest weight (m, n) is decomposed according to the embedding so(3) ⊂ su(3). First, a realisation (a representation in terms of vector fields) of the Lie algebra su(3) is constructed on a space of polynomials of three variables. The special polynomial basis of the representation space is given. In this basis, we find the highest weight vectors of the representation of the Lie subalgebra so(3) and in this way the representation space is decomposed to the direct sum of invariant subspaces. The process is illustrated by the example of the decomposition of the representation of highest weight (2, 2). As an additional result, the generating function of the decomposition is given
The load-transfer method as a tool for determining the load-displacement curve of piles
Get PDFThe paper presents two applications (software packages) in which the load-transfer method is used for axially loaded Kelly drilled bored piles and displacement ductile iron piles. In the first, the ultimate friction is related to the effective stress via the so-called β method. The β method is refined into three stages to cover the variety of soils typical of Central Europe. For the driven piles, a different approach is presented in which the ultimate shaft friction is related to the reference hammering time. The recorded hammering time profile is fed directly into the software based on the load-transfer method. Analyses of five loading tests are presented proving that the load transfer method in combination with the β method or the recorded hammering time profile is able to compute the load-displacement curve of both replacement and displacement piles with a reasonable accuracy in various geological conditions
Numerical solution for stochastic Volterra-Fredholm integral equations with delay arguments
Get PDFWe present a method for computing the stochastic operational matrix of integration to advance the study of stochastic Volterra-Fredholm integral equations (SVFIEs) based on delay arguments. First, the method evaluates the combined effects of the delay and its parameters on the accuracy improvement of the convergence rate. Our results can be applied to SVFIEs, with the operational delay matrices of the block pulse function simplified to algebraic ones. Numerical calculations were performed on a PC using Python 3 programs. Results also demonstrate the accuracy of approximate solutions; arithmetic operations are carried out without the need for derivation or integration
Regional development between theory and practice 2023
No full textBefore European society could cope with the effects of the Covid-19 pandemic, new problems were arose caused by Russian aggression in Ukraine. This has brought not only new security threats and a new wave of migrants, but also new and hitherto unexpected problems in terms of energy prices and availability. All these problems must be tackled not only by Europe as a whole, by individual states, but also by every region, city, or municipality. The aim of the conference is to create a platform for the transfer of new scientific knowledge and experience, how to analyse and solve the problems that have arisen, i.e., to propose ways, tools, and innovations for dealing with their consequences.
The conference key topics were following:
Impacts of Climate Change on Cities and Regions.
Participatory Democracy in Sustainable Regional Development.
New Security Aspects of Regional Development.
Sustainable Urban and Regional Mobility.
Impacts of Antipandemic Measures on the Management of Cities and Regions.
Tourism in the Post-Covid Time.
Circular Economy of Cities and Regions.
New Energy Challenges in the Management of Cities and Regions.
Date: June 1, 2023Venue: Prague, Czech RepublicURL: https://www.muvs.cvut.cz/rozvoj-veda-a-vyzkum/konference/
Organized by:Masaryk Institute of Advanced Studies, Czech Technical University in Prague
Guest editor:Vladimíra Šilhánková
Scientific committee:Lulzim Beqiri, Faculty of Architecture and Spatial Planning, University of Economics and Technology PristinaAnna Karwińska, Faculty of Political Science, Sociology and Philosophy, University of Economics KrakowJan Koutný, Professor Emeritus, Faculty of Architecture, Brno University of TechnologyBohumil Kováč, Faculty of Architecture, Slovak University of Technology in BratislavaZita Kučerová, Centre for Investment, Development and Innovation Hradec KrálovéEleonóra Marišová, Faculty of European Studies and Regional Development, Slovak University of Life Sciences NitraMartin Maštálka, Masaryk Institute of Advanced Studies, CTU in PragueMichael Pondělíček, Masaryk Institute of Advanced Studies, CTU in PragueAntonio Roldán-Ponce, University of Applied Sciences, DresdenEgon Smeral, MODUL University, ViennaVladimíra Šilhánková, Masaryk Institute of Advanced Studies, CTU in Prague
Local organizing committee:Vladimíra ŠilhánkováMichael PondělíčekMartin MaštálkaEva BobkováIveta Šilhánková
Guarantor of the peer review process: Eva Bobková
Guarantor of language editing: Eva Bobkov
Cementitious material development for additive fabrication
Get PDFFor the 3D STAR project and 3D printing purposes, a special fine-grained cement mixture from locally available raw materials was developed. The reason for the development of the custom mixture was the possibility of arbitrary optimization of the developed mixture at any stage of the project and for any type of application. Mix design, printing head and the entire system from mixing to extrusion was the subject of research and development for this project. It was therefore necessary to address both issues in parallel and to respond in both sectors to the realities arising from the partial results of the different groups involved in the development