Fourier analysis of the traffic flow intensity

The relevance of this work is determined by the need to find modern ways to process the information about traffic flows for regulating and controlling the movement of transport and pedestrians, to reduce congestion, road accidents, etc. The object of study is a part of road with heavy two-way traffic, equipped with a software and hardware complex that allows to measure the characteristics of the transport flow. The subject of the study is the daily intensity of the cars flow during the week, from Monday to Sunday. The purpose of this study is to analyze the amplitudes, frequencies, and periods of harmonic functions obtained by decomposing the time series of road traffic intensities to identify the main patterns of traffic flow formation. As a theoretical and methodological approach, the decomposition of the function of the traffic flow intensity in the Fourier series with respect to harmonic functions is used. The approach developed by the authors using the fast Fourier transform procedure made it possible to determine the amplitude-frequency characteristics of the time series under consideration, which is a scientific novelty of the analysis. It is proposed to use the «period-amplitude» characteristics as physically more meaningful instead of the «frequency-amplitude» dependencies traditionally used for the analysis. The processing of data obtained from software and hardware complexes allowed us to determine dependences of the car flow intensity on the road of the Perm city at different averaging intervals, to describe the features of the motor transport movement on the road under consideration. As a result of the study, the amplitude-frequency characteristics of time series are obtained. It is shown that the individual harmonics of the Fourier series expansion of the traffic flow intensity, which exhibits the properties of a random function, duplicate the periodicity of the global, local, and intermediate extremes of the original function and have similar periods. The practical significance consists in the use of the decomposition of the function of the traffic flow intensity in the Fourier series of harmonic functions for predicting traffic flows, controlling the operation of traffic lights, monitoring the operation of equipment, as well as in the reconstruction, design and construction of roads and road objects. The study will continue in the direction of obtaining, processing and determining the «period-amplitude» characteristics for time series of traffic flow intensity for other road networks

Application of the wavelet analysis to research the traffic flow intensity

The relevance of the work is the specific properties of the wavelet analysis, which make it possible to identify not only the amplitude-scale (frequency) characteristics of the time series under consideration, but also the evolution of these characteristics during the observation time. As a result of the study, it is advisable to identify those indicators of the intensity of traffic flow that may turn out to be indicators of possible problematic situations (congestion, traffic accidents, etc.). It is advisable to use them in the future when regulating and controlling traffic on the basis of processing information about traffic flows that comes from stationary video recording complexes of traffic violations. The object of study is a road with intensive one-way traffic, equipped with a software and hardware complex that allows measuring the characteristics of the flow of motor transport. The subject of the study is the daily intensity of the flow of cars. The purpose of this study is to identify patterns in the indicators evolution obtained using wavelet analysis as a result of processing of the time series of the car traffic intensity on the road network. As a theoretical and methodological approach, the wavelet transforms using the MHat wavelet, and the Morlet wavelet is used. The approach used by the authors allowed us to establish the correspondence of some characteristics obtained during the wavelet analysis with the evolution of the traffic flow intensity function during the daily observation time, which is the scientific novelty of the study. The wavelet analysis of the data of the video surveillance software and hardware complexes obtained during the day allowed us to construct time dependences of amplitude-scale (frequency) indicators of the car traffic intensity on the road connecting the central and rear areas of the city of Perm. As a result of the study of time series, experimental three-dimensional distributions of wavelet images, scalograms, skeletons and scalegrams of the function of the daily intensity of the traffic flow were obtained. An explanation of the characteristic features of the obtained dependencies and their relationship with the initial function of the traffic flow intensity is proposed. The practical significance lies in obtaining amplitude-scale (frequency) characteristics as a result of wavelet analysis of the traffic intensity using MHat and Morlet wavelets, which is of practical interest from the point of view of predicting the movement of vehicles, controlling the operation of traffic lights, monitoring the operation of equipment, etc. The direction of further research is to obtain, process, analyze and generalize the results of performing amplitude-scale wavelet analysis for time series of traffic flow intensity on parts of the road network with different vehicle traffic intensity

Application of the Hurst index to research the traffic flow intensity

The relevance of the work is due to the predictive properties of the Hurst indicator (index), which make it possible to identify the presence/absence of a trend in the observed stochastic process, which it is advisable to use when regulating and controlling traffic to reduce congestion, traffic accidents based on processing information about traffic flows coming from stationary video recording complexes of traffic violations. The object of investigation is a section of road with intensive one-way traffic, equipped with a software and hardware complex that allows measuring the characteristics of the flow of motor transport. The subject of the study is the daily intensity of the cars flow during the week, from Monday to Sunday. The purpose of this study is to identify the patterns of evolution of the indicators included in the Hurst index, based on the processing of time series of the intensity of motor transport traffic on the road network. As a theoretical and methodological approach, the rescaled range analysis, or the definition of Hurst exponent, is used. The approach developed by the authors allowed us to establish the regularities of the evolution of mean values, standard deviations, accumulated and rescaled range, Hearst exponents, which is the scientific novelty of the performed analysis. Data processing of video surveillance software and hardware complexes made it possible to construct time-dependent indicators of the intensity of car traffic on a road with a consistently high flow of vehicles connecting the central and remote areas of the city of Perm, at various intervals of averaging by days of the week. As a result of the study of time series, dependences on the time of average values, standard deviations, accumulated and rescaled ranges, Hearst exponents were obtained. It is shown that the found characteristics of the traffic flow intensity on a road with a high traffic intensity differ significantly from similar characteristics obtained earlier for roads with a relatively low intensity. The practical significance lies in the use of predictive properties of the Hurst indicator in analyzing the intensity of the flow of vehicles for predicting the movement of vehicles, controlling the operation of traffic lights, monitoring the operation of equipment, etc. The direction of further research is to obtain, process and determine rescaled ranges and Hurst exponents for time series of traffic flow intensity on other sections of the road network

Температурный режим системы выпуска автомобиля при пониженных температурах

Currently operation of cars in large cities in winter is the most unfavorable from the point of view of the risk of blocking the exhaust system by condensate accumulated in it. Frequent starts during relatively short period of time, or the cycle of start-up – short run – and subsequent long-term parking at low temperatures are dangerous because the exhaust system does not have time to warm up and remove the accumulated condensate. Daily operation in such modes contributes to rapid accumulation of condensate, and subsequent long-term parking at ambient temperatures below 0˚C are equally dangerous because, depending on the design features of the exhaust system elements, condensation may occur and freeze in the exhaust system, icing can occur inside it or at its exit, causing inability to start the engine. Given that most of the territory of Russia is located in the areas of moderate and cold climate, the relevance of studies, aimed at identifying the patterns of condensate formation and accumulation in the exhaust system, at adjusting on this basis the frequency of condensate removal from the exhaust system, as well as at optimizing the design parameters of the exhaust systems, is quite evident. The objectives of this study were: to identify the features of changes in temperature of the elements of the exhaust system when the automobile engine warms up at low ambient temperature, the effect of various modes of the heater operation on the temperature of the elements of the exhaust system, as well as the features of the temperature change of individual elements of the exhaust system depending on time for various ambient temperatures. To achieve those objectives a series of experiments has been conducted to study the process of starting the «cold» engine, and of its warming up in idle mode. The found dependencies can be used to develop methodology to adjust the recommended periodicity of warming up of the exhaust system, as well as a model of a device that will ensure the absence of condensate in exhaust systems during the operation of cars in large cities during winter period.В настоящее время наиболее неблагоприятной, с точки зрения риска блокировки системы выпуска накопившимся в ней конденсатом, является эксплуатация автомобилей в крупных городах в зимний период. Частые пуски в относительно короткий промежуток времени, либо пуск – короткий пробег – и последующая длительная стоянка при низких температурах опасны тем, что система выпуска отработавших газов не успевает прогреться иудалить накопившийся конденсат. Ежедневная эксплуатация в таких режимах способствует быстрому скоплению конденсата, а последующая длительная стоянка при температуре воздуха ниже 0˚C опасна тем, что в зависимости от конструктивных особенностей элементов выпускной системы возможны замораживание конденсата в системе выпуска отработавших газов, образование ледяной пробки внутри либо на её выходе и, как следствие, невозможность запуска двигателя. Учитывая то, что большая часть территории России находится в зонах умеренного и холодного климата, исследования, направленные на выявление закономерностей формирования уровня накапливания конденсата в системе выпуска отработавших газов, корректирование на этой основе периодичности удаления конденсата из системы выпуска, а также оптимизацию конструктивных параметров систем выпуска отработавших газов, более чем актуальны. Цели данного исследования предусматривали изучение особенностей изменения температуры элементов системы выпуска отработавших газов при прогреве автомобильного двигателя в условиях пониженной окружающей температуры, а также влияния различных режимов работы обогревателя салона на температуру элементов системы выпуска отработавших газов, особенностей изменения температуры отдельных элементов системы выпуска отработавших газов в зависимости от времени для различных температур окружающего воздуха. Для этого проводились экспериментальные исследования по запуску «холодного» двигателя и его прогреву в режиме холостого хода. Установленные закономерности могут лечь в основу разрабатываемой методики корректирования периодичности прогрева системы выпуска отработавших газов, а также модели устройства, которое будет обеспечивать отсутствие конденсата в системе выпуска при эксплуатации автомобилей в крупных городах в зимний период

Patterns of traffic congestion indicator at some intersections of the road network

The average speed and density of road transport are used as indicators of the congestion situation, but do not allow tracking the evolution (stages of formatting, progressing, and vanishing) of traffic congestion. The authors proposed and justified a quantitative indicator of traffic congestion, which allows in an automated mode to identify the congestion situation on the urban road network using hardware and software video recording systems. The purpose of this study is due to the need to study the quantitative characteristics of the proposed indicator at characteristic intersections of urban roads, which will allow us to develop scientifically based recommendations for predicting congestion situations, substantiating, and making optimal decisions on measures to promptly eliminate traffic congestion. The object of study is the traffic flow at three types of intersections of the Perm city road network, equipped with a photo and video recording software and hardware complex. The subject of the study is the regularities of the evolution of the listed deterministic indicators of traffic flows, which can be used for operational forecasting of the formation, development, and elimination of traffic congestion. The theoretical and methodological approach is based on the methods of mathematical statistics used to process the results of observations of traffic flows at different types of intersections using a «sliding window», calculating the average daily value and standard deviation. The initial data were obtained with the help of hardware and software complexes for fixing violations of traffic rules installed on the street and road network of the Perm city. As a result of the study, the rational parameters of the «sliding window» were determined, ensuring the structuring of the traffic congestion indicator; the facts of the congestion situations formation were revealed; the features of the congestion evolution and the presence of problematic traffic directions for which it is advisable to change the traffic light regulation mode were determined. The theoretical and practical significance of the work consists in checking the operability of the proposed indicator and criterion of traffic congestion, which is of practical interest from the point of view of predicting anomalies in the movement of vehicles on the road network, adjusting the operating modes of traffic lights, etc. It is also possible to use the proposed traffic congestion indicator to assess the effectiveness of traffic light regulation on the Perm city road network. The direction of further research is to study the patterns of traffic congestion at intersections of the urban road network, of various types that are not included in this study