Lidé na fakultě
Dr. Ing. Jan Přikryl

2017, 2017 Smart Cities Symposium Prague (SCSP) - IEEE PROCEEDINGS, New York, IEEE Press), ISBN 978-1-5386-3825-5

Automated driving has become an important research trend in the field of cooperative intelligent transportation systems and their applications in smart cities. Automated driving both increases road capacity and eliminates human errors, one of the most common reason of traffic accidents. Both these aspects influence significantly the quality of life, which is a major goal of smart city initiatives. Management of automated vehicles by urban road infrastructure is a rather new subject and not so much practical development has been reported yet. Unfortunately, the available information is spread over fragments within other resources dealing with automated vehicles. In this paper, we provide an overview of major functionalities that have to be provided by both road infrastructure and an automated vehicle so that the vehicle can optimally navigate through an urban network with signalized intersections and we review the state-of-the-art publications providing approaches relevant to these core functionalities.

Stať ve sborníku z prestižní konf.

2017, Proceedings of Seminar Programs and Algorithms of Numerical Mathematics 18, Praha, Matematický ústav AV ČR, v. v. i.), p. 89-96), ISBN 978-80-85823-67-7

A key element of microscopic traffic flow simulation is the so-called car-following model, describing the way in which a typical driver interacts with other vehicles on the road. This model is typically continuous and traffic micro-simulator updates its vehicle positions by a numerical integration scheme. While increasing the order of the scheme should lead to more accurate results, most micro-simulators employ the simplest Euler rule. In our contribution, inspired by [1], we will provide some additional details that have to be addressed when implementing higher-order numerical integration schemes for CFMs and we will show that the theoretical gain of higher-order methods is unfortunately masked out by the stochastic nature of real-world traffic flow.

Stať ve sborníku z prestižní konf.

2015, Neural Network World, 25 (1), p. 35-52), ISSN 1210-0552

One of the key indicators of the quality of service for urban transportation control systems is the queue length. Even in unsaturated conditions, longer queues indicate longer travel delays and higher fuel consumption. With the exception of some expensive surveillance equipment, the queue length itself cannot be measured automatically, and manual measurement is both impractical and costly in a long term scenario. Hence, many mathematical models that express the queue length as a function of detector measurements are used in engineering practice, ranging from simple to elaborate ones. The method proposed in this paper makes use of detector time-occupancy, a complementary quantity to vehicle count, provided by most of the traffic detectors at no cost and disregarded by majority of existing approaches for various reasons. Our model is designed as a complement to existing methods. It is based on Gaussian-process model of the occupancy-queue relationship, it can handle data uncertainties, and it provides more information about the quality of the queue length prediction.

Článek v periodiku excerpovaném SCI Expanded

2015, Proccedings of the 18th IEEE International Conference on Intelligent Transportation Systems, Piscataway, IEEE), p. 894-899), ISBN 978-1-4673-6595-6

Distributed control mechanisms have been studied in past decades in different application areas. Currently, multiagent systems are a popular topic also in ITS systems, where numerous approaches to distribution of system intelligence are being tested. One of the main problems in distributed control, however, remains the guarantee of reaching the global optimum-while most of the applications perform sufficiently well, there is no way to tell that they cannot perform even better, or that they may fail under certain operating conditions. Luckily, for certain control paradigms such guarantees may be given. In this paper we study two approaches to distributed control, namely distributed LQ control and distributed non-lonear control using COBYLA algorithm, and apply them to urban traffic control scenario. We show that the convergence conditions are met and results achieved with distributed control converge to those of centralised control mechanisms.

Stať ve sborníku z prestižní konf.

2015, Smart Cities Symposium Prague 2015 Proceedings - Czech Technical University in Prague, Praha, České vysoké učení technické v Praze, Fakulta dopravní), p. 39-39), ISBN 978-80-01-05742-1

The paper presents urban traffic control method suitable and tested for a small urban areas enabling more fluent traffic and thus increasing the throughput of the controlled area. The model is implemented in the adaptive Traffic Dependent Control module for higher control of the area designed for the optimization of the intersection signal plans, providing the best improvements for intersections with irregular traffic.

Abstrakt ve sborníku z prestižní konf.

2015, 2015 Smart Cities Symposium Prague (SCSP), New York, IEEE Press), ISBN 978-1-4673-6727-1

The paper presents urban traffic control method suitable and tested for a small urban areas enabling more fluent traffic and thus increasing the throughput of the controlled area. The model is implemented in the adaptive Traffic Dependent Control module for higher control of the area designed for the optimization of the intersection signal plans, providing the best improvements for intersections with irregular traffic.

Stať ve sborníku z prestižní konf.

2014, Telematics - Support for Transport, Heidelberg, Springer), p. 166-173), ISBN 978-3-662-45316-2, ISSN 1865-0929

We made an analysis on the selected road in Prague road network, by help of research project SATEL, which aimed to automated detection of traffic excesses (AID) and estimating travel times on urban road net. For data collection were intended two types of traffic detectors – static data from loops, videodetection etc. and data from floating cars. The project introduces a new method for obtaining traffic data, which includes estimated travel times through data fusion from floating cars and traffic road detectors from on-line traffic and calibration by historical data. The proposed model uses the real data from traffic detectors with floating cars and it was proved its strength and application for estimation traffic excesses and travel times on the road network as well.

Stať ve sborníku z mezinár. konf.

2014, Telematics - Support for Transport, Heidelberg, Springer), p. 166-173), ISBN 978-3-662-45316-2, ISSN 1865-0929

We made an analysis on the selected road in Prague road network, by help of research project SATEL, which aimed to automated detection of traffic excesses (AID) and estimating travel times on urban road net. For data collection were intended two types of traffic detectors – static data from loops, videodetection etc. and data from floating cars. The project introduces a new method for obtaining traffic data, which includes estimated travel times through data fusion from floating cars and traffic road detectors from on-line traffic and calibration by historical data. The proposed model uses the real data from traffic detectors with floating cars and it was proved its strength and application for estimation traffic excesses and travel times on the road network as well.

Stať ve sborníku z prestižní konf.

2013, Proceedings of Seminar Programs and Algorithms of Numerical Mathematics 16, Praha, Academy of Sciences of the Czech Republic), p. 162-167), ISBN 978-80-85823-62-2

The current powerful graphics cards, providing stunning real-time visual effects for computer-based entertainment, have to accommodate powerful hardware components that are able to deliver the photo-realistic simulation to the end-user. Given the vast computing power of the graphics hardware, its producers very often offer a programming interface that makes it possible to use the computational resources of the graphics processors (GPU) to more general purposes. This step gave birth to the so-called GPGPU (general-purpose GPU) processors that – if programmed correctly – are able to achieve astonishing performance in floating point operations. In this paper we will briefly overview nVidia CUDA technology and we will demonstrate a process of developing a simple GPGPU application both in the native GPGPU style and in the add-ons for Matlab (Jacket and Parallel Toolbox).

Stať ve sborníku z prestižní konf.

2013, Proceedings of 16th International IEEE Conference on Intelligent Transportation Systems, Red Hook, NY, Curran Associates), p. 41-46), ISBN 978-1-4799-2914-6, ISSN 2153-0009

This paper introduces a new model of traffic flow between two signalized intersections. The model originated from our effort to improve older, macroscopic model based on the conservation law of vehicles. In order to keep the proposed model simple and numerically tractable, we make several simplifications: we do not take into account acceleration and deceleration of vehicles and different preferences of drivers and we classify the movements of vehicles into two classes: (i) a stopped vehicle, waiting in a queue, and (ii) a vehicle moving with a constant cruising speed. Under these assumptions the flow of vehicles between two intersections can be described by a piece-wise linear function as a combination of several “ramp” functions. We demonstrate the behavior of the proposed model on an simulated scenario of two signalized intersections.

Stať ve sborníku z prestižní konf.

2012, Archives of Transport System Telematics, 5 (4), p. 26-30), ISSN 1899-8208

As the urban traffic volumes reach their daily peak values, the surface traffic in modern cities suffers from frequent breakdowns and traffic jams. One of possibilities that could mitigate the problem is the deployment of smarter automatic systems of urban traffic control. Our paper demonstrates a development version of such a system. The system is based on adaptive feedback control approach. It makes use of filtering techniques to account for measurement imperfections and implements the rolling horizon method for optimal signal control. We compare the performance of the proposed system with two typical control approaches - pre-timed (or fixed) control, and traffic actuated (or dynamic) control. Different scenarios will be compared, including rapid changes in traffic volumes and reactions to incidents. The comparison is carried out using our demonstrator tool, based on TSS Aimsun micro-simulator. In order to keep the calibrated simulation as close to reality as possible, in the comparison runs we use real dense input volume measurements and simulate also the behavior of intersection controllers.

Článek v odborném recenzovaném periodiku

2012, Transport Systems Telematics 12th International Conference, Silesian University of Technology), p. 76-76), ISBN 978-83-927504-1-3

As the urban traffic volumes reach their daily peak values, the surface traffic in modern cities suffers from frequent breakdowns and traffic jams. One of possibilities that could mitigate the problem is the deployment of smarter automatic systems of urban traffic control. Our paper demonstrates a development version of such a system. The system is based on adaptive feedback control approach. It makes use of filtering techniques to account for measurement imperfections and implements the rolling horizon method for optimal signal control. We compare the performance of the proposed system with two typical control approaches - pre-timed (or fixed) control, and traffic actuated (or dynamic) control. Different scenarios will be compared, including rapid changes in traffic volumes and reactions to incidents. The comparison is carried out using our demonstrator tool, based on TSS Aimsun micro-simulator. In order to keep the calibrated simulation as close to reality as possible, in the comparison runs we use real dense input volume measurements and simulate also the behavior of intersection controllers.

Abstrakt ve sborníku z mezinár. konf.

2012, Transactions on Transport Sciences, 5 (2), p. 55-62), ISSN 1802-971X

Mathematical modeling is an inevitable part of system analysis and design in science and engineering. When a parametric mathematical description is used, the issue of the parameter estimation accuracy arises. Models with uncertain parameter values can be evaluated using various methods and computer simulation is among the most popular in the engineering community. Nevertheless, an exhaustive numerical analysis of models with numerous uncertain parameters requires a substantial computational effort. The purpose of this paper is to show how the computation can be accelerated using a parallel configuration of graphics processing units (GPU). The assessment of the computational speedup is illustrated with a case study. The case study is a simulation of Highway Capacity Manual 2000 Queue Model with selected uncertain parameters. The computational results show that the parallel computation solution is efficient for larger amount of samples when the initial and communication overhead of parallel computation becomes a sufficiently small part of the whole process.

Článek v periodiku z pozitivního seznamu RVVI cizojazyčně

2011, IDAACS'2011 - Proceedings of the 6th IEEE International Cnonference on Intelligent Data Acquisition and Advanced Computing Systems, Prague, IEEE, THEY, CTU), p. 672-677), ISBN 978-1-4577-1423-8

In the 1960s E. Fama developed the efficient market hypothesis (EMH) which asserts that the financial market is efficient if its prices are formed on the basis of all publicly available information. That means technical analysis cannot be used to predict and beat the market. Since then, it was widely examined and was mostly accepted by mathematicians and financial engineers. However, the predictability of financial-market returns remains an open problem and is discussed in many publications. Usually, it is concluded that a model able to predict financial returns should adapt to market changes quickly and catch local dependencies in price movements. The Bayesian vector autoregression (BVAR) models, support vector machines (SVM) and some other were already applied to financial data quite succesfully. Gaussian process (GP) models are emerging non-parametric Bayesian models and in this paper we test their applicability to financial data. GP model is fitted to daily data from U.S. commodity markets. For a comparison BVAR model and benchmark model that is commonly used in todays financial mathematics are chosen. The results indicate that GP models are applicable to financial data as well as BVAR models.

Stať ve sborníku z prestižní konf.

2010, MELECON 2010, 15th IEEE Mediterranian Electromechanical Conference, Valletta, Malta, Malta (Valletta), IEEE Malta Section, Region 8), p. 172-177), ISBN 978-1-4244-5794-6

Soft sensors are a valuable alternative to the traditional hardware sensors, which are indispensable in configuration of modern systems. They are often used in process industry, but other applications are possible. This paper describes a possible application of soft sensor for faulty measurement detection and reconstruction in urban traffic. One of the key indicators of traffic control quality in urban traffic control (UTC) systems is the queue length. With the exception of some expensive surveillance equipment, the queue length itself cannot be measured directly. Many methods that estimate the queue length from detector measurements are used in engineering practice, ranging from simple to elaborate ones. The proposed method is a soft sensor based on Gaussian process (GP) model of the traffic queue length in a traffic cross-section. The resultant soft sensor detects single measurement outliers as well as longer lasting faults and replaces the faulty measurements with model prediction.

Stať ve sborníku z mezinár. konf.

2009, 12th IFAC Symposium on Control in Transportation Systems Control in Transportation Systems, Long Beach, IFAC), p. 456-461), ISBN 978-3-902661-50-0

One of the key indicators of traffic control quality in urban traffic control (UTC) systems is the queue length. Even in unsaturated conditions, longer queues indicate longer travel delays and higher fuel consumption. With the exception of some expensive surveillance equipment, the queue length itself cannot be measured directly. Many methods that estimate the queue length from detector measurements are used in engineering practice, ranging from simple to elaborate ones. The proposed method is based on Gaussian process (GP) model of the occupancy-queue relationship. It can handle data uncertainties and provides more information about the quality of the queue length prediction.

Stať ve sborníku z mezinár. konf.

2006, Proceedings of the 32nd Annual Conference of the IEEE Industrial Electronics Society, ???, IEEE Industrial Electronic Society), p. 4695-4700), ISBN 1-4244-0136-4, ISSN 1553-572X

Bayesian approach to decision-making is successfully applied in control theory for design of control strategy. The approach is based on the assumption that only one decision-maker is an active part of the system. This assumption was recently relaxed yielding distributed Bayesian decision-making theory. This extension is useful for large distributed systems which intrinsically contains a lot of uncertainty. In this paper, we apply the theory to distributed control of one example of such a system, the surface traffic network in dense urban areas.

Stať ve sborníku z mezinár. konf.

2006, Proceedings of 7th International PhD Workshop Young Generation Viewpoint, Praha, ÚTIA AV ČR), p. 177-182), ISBN 80-903834-1-6

The traditional way of controlling urban traffic is using centralised control approaches: There is a single control centre where decisions are made about the traffic control in the whole urban area. Currently, this paradigm is shifting towards more decentralised hierarchical approaches with smaller control centres serving sub-regions of the intersection network in a city. The paper reviews possible directions of future development in this area, which are the use of distributed or multi-agent systems in the form of peer-to-peer networks of decision-makers.

Stať ve sborníku z mezinár. konf. cizojazyčně

2006, ISBN 80-903834-1-6

Sborník z mezinár. konf. cizojazyčně

2005, Self-Orgranization and Autonomic Informatics (I), Amsterdam, IOS Press), p. 62-76), ISBN 1-58603-577-0

Bayesian approach to decision making is successfully applied in control theory for design of control strategy. However, it is based on on the assumption that a decision-maker is the only active part of the system. Relaxation of this assumption would allow us to build a framework for design of control strategy in multi-agent systems. In Bayesian framework, all information is represented by probability density functions. Therefore, communication and negotiation of Bayesian agents also needs to be facilitated by probabilities. Recent advances in Bayesian theory make formalization these tasks possible. In this paper, we bring the existing theoretic results together and show their relevance for multi-agent systems. The proposed approach is illustrated on the problem of feedback control of an urban traffic network.

Kapitola v vědecké knize

2005, Proceedings of the 8th COST 276 Wokshop, Trondheim, Norwegian Society on Signal Processing), p. 83-86), ISBN 82-997105-0-2

With the growing popularity of automotive cameras, their price drops. Within several years we can expect that a middle-class automobile will use several cameras to observe its surroundings and all video signal paths will be digital. As the bandwidth needed for uncompressed digital video transmission is still rather high, it is possible that these digital links will have to use some kind of video compression. In this paper we attempt to evaluate the performance of our road sign detector on a series of lossy-compressed image sequences with degrading visual quality.

Stať ve sborníku z mezinár. konf.

2004, Proceedinds of the 6th COST 276 Workshop on Information and Knowledge Management for Integrated Media Communication, Thessaloniki, Informatics and Telematics Institute Centre for Research and Technology, Hellas,), p. 72-76), ISBN 960-88136-0-3

Automatic identification of vehicles has turned out to be an important research issue. This paper presents a license plate recognition system designed especially designed for road traffic survey applications. The system consists of autonomous cameras transmitting captured video signal over a short-range wireless link to central computer that runs image-based license plate recognition software. The output of the system is a database of encoded license plate numbers together with corresponding time stamps.

Stať ve sborníku z mezinár. konf.

2003, Computers & Graphics, 27 (4), p. 569-580), ISSN 0097-8493

We present a new method for computing visibility from a polygonal region in the plane considering a set of line segments as occluders. The proposed method provides a comprehensive description of visibility from the given region. We represent sets of occluded rays using a hierarchical partitioning of dual space (line space). The line space partitioning is maintained by a BSP tree that provides efficient operations on the sets of lines. The implementation shows that the method is suitable for computing potentially visible sets in large scenes with various visibility characteristics.

Článek v periodiku excerpovaném SCI Expanded

2003, WSCG 2003 - Posters, Pilsen, University of West Bohemia), p. 37-40), ISBN 80-903100-2-8

This paper presents experimental system for simulation and visualisation of the light interactions in outdoor scenes. The simulation is obtained by the hierarchical Monte Carlo radiosity method that was extended to handle parallel light sources, specular reflections, skylight etc.

Stať ve sborníku z mezinár. konf. cizojazyčně

2003, ISBN 80-01-02840-2

Sborník z mezinár. konf. cizojazyčně

1999

Sborník z mezinár. konf.

1996, Multimedia '96, Wien, Springer), p. 68-78), ISBN 3-211-82876-1

Three-Dimensional Information System on the World Wide Web

Stať ve sborníku z mezinár. konf.

1995, The Third International Conference in Central Europe on Computer Graphics and Visualization 95 - Conference Proceedings. Volume II, Plzeň, Západočeská universita), p. 283-288), ISBN 80-7082-186-8

Data compression in general is not a new problem... this paper we will deal with image data compression. We will discuss various approaches to the image compression and we will present a new method which does not suffer from some disadvantages of methods widely used.

Stať ve sborníku z mezinár. konf. cizojazyčně

1995, Proceedings of the Third International Conference in Central Europe on Computer Graphics and Visualisation 95, Plzeň, Západočeská universita), p. 439-447), ISBN 80-7082-187-6

Stať ve sborníku z mezinár. konf. cizojazyčně

1995, Workshop 95, Praha, České vysoké učení technické v Praze), p. 167-168)

Stať ve sborníku Workshop ČVUT

1995, Poster 1995, Praha, České vysoké učení technické v Praze, Fakulta elektrotechnická), p. 135-135)

Stať ve sborníku z lokální konf. cizojazyčně

1994, CTU Seminar 94, Praha, České vysoké učení technické v Praze), p. 93-94)

Stať ve sborníku Workshop ČVUT

1994, Proceedings of First European PVM Users Group Meeting, Roma, University of Roma), p. 1-10)

Stať ve sborníku z mezinár. konf.

1994, Proceedings of Winter School of Computer Graphics and CAD Systems 94, Plzeň, Západočeská universita), p. 113-117)

Stať ve sborníku z lokální konf. cizojazyčně

1994, Proceedings of Spring School on Computer Graphics, Bratislava, Univerzita Komenského), p. 108-116), ISBN 80-223-0801-3

Stať ve sborníku z mezinár. konf.