190 research outputs found

    Методика прогноза дождевых паводков в бассейне Верхнего Амура (на примере р. Онон)

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    Актуальность работы. Бассейн Амура относится к паводкоопасному региону. Дождевые наводнения в бассейне верхнего Амура, носящие катастрофический характер, наблюдались за последнее столетие 8 раз. Они охватывали одновременно огромные территории, сопровождались человеческими жертвами, разрушением жилых и производственных зданий, инженерных коммуникаций. Эффективным способом борьбы с наводнениями является регулирование речного стока путем создания водохранилищ. Существующих водохранилищ в речной системе Амура не хватает, чтобы эффективно регулировать сток воды. Их строительство предусмотрено в планах дальнейшего освоения региона. Прогнозы притока паводковых вод являются одной из ключевых задач, позволяющих минимизировать ущерб от паводков и определить наиболее рациональный режим эксплуатации существующих и вновь создаваемых водохранилищ. Цель работы: на примере реки Онон исследовать процессы формирования наводнений и разработать методику их краткосрочного прогноза в бассейне верхнего Амура. Методы исследования: методы водного баланса, географо-гидрологические, статистические, математическое моделирование процессов формирования стока. Результаты. Для реализации прогноза ежедневных расходов (уровней) воды дождевых паводков адаптирована концептуальная модель Д.А. Буракова, используемая в сибирских подразделениях Росгидромета. В качестве ландшафтно-гидрологической основы построения модели принято деление бассейна на районы и высотные зоны. Исходной территориальной единицей осреднения гидрометеорологических характеристик в бассейнах горных рек является высотная зона. В пределах высотной зоны территориальная неравномерность распределения запасов снега и емкостного поглощения воды учитывается с помощью распределений вероятности. Отрезки времени, в течение которых суточное поступление воды на поверхность бассейна превышает суточное испарение и просачивание, образуют последовательные паводкообразующие периоды. Для каждых суток паводкообразующего периода рассчитывается водоотдача высотных зон на основе инфильтрационно-емкостной модели Е.Г. Попова, гравитационный запас воды на склонах и приток в русловую сеть. В основу модели расчета добегания притока воды по русловой сети положен интеграл свёртки (генетическая формула паводка). В результате выполненных исследований разработана методика прогноза ежедневных уровней воды в русловой системе р. Онон. Испытания методики в оперативном режиме в Читинском гидрометеорологическом центре показали ее эффективность.Relevance. The Amur basin is situated in a flood-inclined region. Over the course of the past century the disastrous pluvial flooding have occurred in the basin eight times. They covered huge territories, took peopleґs lives and caused considerable damage to residential and industrial buildings, engineering systems. One of the efficient methods to struggle the floods is to regulate the river run-off developing flood-control reservoirs. The number of existing reservoirs on the Amur river system is insignificant to control efficiently the river run-off. Their building is tied with further region development. The forecast of flood water inflow allows minimizing damage and identifying the most rational reservoir release rules for the existing and expected reservoirs. Aim of the research is to investigate the floods formation by the example of the Onon river and to develop the methods for short-term forecast of floods in the upper Amur basin. Research methods: water balance method, geographical and hydrological methods, statistical method, mathematical modeling of run-off formation. Results. The Burakovґs conceptual model is adapted to forecast daily rain floods water flows. This model is used by the Siberian department of the Federal Service for Hydrometeorology and Environmental Monitoring of Russia. The landscape and hydrological basis for this model is the basin division into areas and altitudinal zones. The altitudinal zone is an initial territorial unit of averaging the hydrological characteristics of mountain rivers. Within the altitudinal zone, territorial irregularity of snow cover distribution and capacitive water absorption are taken into account by probability distribution. The periods, when the diurnal water entry to the surface of the basin exceeds the diurnal evaporation and infiltration, compose successive flood-forming periods. For each day of a flood-forming period, the water yield is estimated using the Popovґs infiltration capacitive model. Besides, the gravitational water storage on the slopes and the inflow in the channel network are calculated. The method, describing water lag along the river channels, is based on applying the convolution integral (the genetic flood formula). As a result of the research, the author has developed the method of forecasting daily water levels in the Onon riverbed system. The method was applied by the Chita department of the Federal Service for Hydrometeorology and Environmental Monitoring of Russia and proved its efficiency

    How do drivers overtake pedestrians? Evidence from field test and naturalistic driving data

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    For pedestrians, the risk of dying in a traffic accident is highest on rural roads, which are often characterized by a lack of sidewalks and high traffic speed. In fact, hitting the pedestrian during an overtaking attempt is a common crash scenario. To develop active safety systems that avoid such crashes, it is necessary to understand and model driver behavior during the overtaking maneuvers, so that system interventions are acceptable because they happen outside drivers’ comfort zone. Previous modeling of driver behavior in interactions with pedestrians primarily focused on road crossing scenarios. The aim of this study was, instead, to address pedestrian-overtaking maneuvers on rural roads. We focused our analysis on how drivers adjust their behavior with respect to three safety metrics (in order of importance): 1) minimum lateral clearance when passing the pedestrian, 2) overtaking speed at that moment, and 3) the time-to-collision at the moment of steering away to start the overtaking maneuver.The influence of three factors on the safety metrics was investigated: 1) walking direction (same as the overtaking vehicle or opposite), 2) walking position (on the edge of the vehicle lane or 0.5 m away from the edge on the paved shoulder), and 3) oncoming traffic (absent or present). Seventy-seven overtaking maneuvers in France from the naturalistic driving study UDRIVE and 297 maneuvers in Sweden from field tests were analyzed. Bayesian regression was used to model how minimum lateral clearance and overtaking speed depended on the three factors. Results showed that drivers maintained smaller minimum lateral clearance and lower overtaking speed when the pedestrian was walking in the opposite direction, on the lane edge, or when oncoming traffic was present. Minimum lateral clearance and time-to-collision were only weakly correlated with overtaking speed. The regression models predicted distributions similar to those actually observed in the data. The time-to-collision at the moment of steering away was comparable in value to the time-to-collision used by Euro NCAP for testing active safety systems in car-to-pedestrian longitudinal scenarios since 2018.This study is the first to analyze driver behavior when overtaking pedestrians, based on field test and naturalistic driving data. Results suggest that pedestrian safety is particularly endangered in situations when the pedestrian is walking opposite to traffic, close to the lane, and when oncoming traffic is present. The Bayesian regression models from this study can be used in active safety systems to model drivers’ comfort in overtaking maneuvers

    Complex pricing and consumer-side attention

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    This paper analyzes a market in which two horizontally differentiated firms compete by setting menus of two-part tariffs, and in which some consumers are not informed about the linear per-unit price component. We consider two regulatory interventions that limit firms’ ability to price discriminate: (i) diminishing the range of contracts via a reduction in the number of two-part tariffs offered (which prohibits inter-group price discrimination), and (ii) a reduction in tariff complexity via the abolishment of linear fees (which prohibits inter- and intra-group price discrimination). We characterize the effects of these interventions on firm profits and (informed and uninformed) consumer welfare, and identify conditions for the optimal policy. Our results provide insights for the evaluation of recent policy interventions (e.g., the regulation of roaming charges in the EU market)

    How do oncoming traffic and cyclist lane position influence cyclist overtaking by drivers?

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    Overtaking cyclists is challenging for drivers because it requires a well-timed, safe interaction between the driver, the cyclist, and the oncoming traffic. Previous research has investigated this manoeuvre in different experimental environments, including naturalistic driving, naturalistic cycling, and simulator studies. These studies highlight the significance of oncoming traffic—but did not extensively examine the influence of the cyclist’s position within the lane. In this study, we performed a test-track experiment to investigate how oncoming traffic and position of the cyclist within the lane influence overtaking. Participants overtook a robot cyclist, which was controlled to ride in two different lateral positions within the lane. At the same time, an oncoming robot vehicle was controlled to meet the participant’s vehicle with either 6 or 9 s time-to-collision. The order of scenarios was randomized over participants. We analysed safety metrics for the four different overtaking phases, reflecting drivers’ safety margins to rear-end, head-on, and side-swipe collisions, in order to investigate the two binary factors: 1) time gap between ego vehicle and oncoming vehicle, and 2) cyclist lateral position. Finally, the effects of these two factors on the safety metrics and the overtaking strategy (either flying or accelerative depending on whether the overtaking happened before or after the oncoming vehicle had passed) were analysed. The results showed that, both when the cyclist rode closer to the centre of the lane and when the time gap to the oncoming vehicle was shorter, safety margins for all potential collisions decreased. Under these conditions, drivers—particularly female drivers—preferred accelerative over flying manoeuvres. Bayesian statistics modelled these results to inform the development of active safety systems that can support drivers in safely overtaking cyclists

    Finite-Element Discretization of Static Hamilton-Jacobi Equations Based on a Local Variational Principle

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    We propose a linear finite-element discretization of Dirichlet problems for static Hamilton-Jacobi equations on unstructured triangulations. The discretization is based on simplified localized Dirichlet problems that are solved by a local variational principle. It generalizes several approaches known in the literature and allows for a simple and transparent convergence theory. In this paper the resulting system of nonlinear equations is solved by an adaptive Gauss-Seidel iteration that is easily implemented and quite effective as a couple of numerical experiments show.Comment: 19 page

    Электрооборудование агрегата перекачки топлива

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    Объектом исследования является частотно-регулируемый электропривод переменного тока электронасосного агрегата. Целью выпускной квалификационной работы является проектирование электрооборудования и асинхронного электропривода насосного агрегата. В результате исследования была разработана системы регулирования насосного агрегата и защит. Выпускная квалификационная работа выполнена с помощью программ MATLAB, Mathcad 14, в текстовом редакторе MS Word и представлена на компакт - диске (в конверте на обороте обложки).Probe plant is the frequent-regulated electric drive of alternate current of the electropump aggregate. The purpose of final qualification operation is projection of electric equipment and the asynchronous electric drive of the pumping aggregate. As a result of probe has been developed regulating systems of the pumping aggregate and guards. Final qualification operation is executed by means of programs MATLAB, Mathcad 14, in text editor MS Word and is presented on a compact set - a disk (in an envelope on the back of a cover)

    Entwicklung und Erprobung eines Beratungskonzeptes zur nachhaltigen Entwicklung landwirtschaftlicher Betriebe

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    In der landwirtschaftlichen Beratung – auch bei Ökobetrieben – werden in der Regel produktionstechnische oder betriebswirtschaftliche Fragestellungen bearbeitet. Eine Beratung, die alle Nachhaltigkeitsdimensionen umfasst und dem Betriebsleiter ein Instrument an die Hand gibt, in dem der Gesamtbetrieb widergespiegelt wird, fehlt bislang. Ziel des noch laufenden Projektes ist die Entwicklung eines Beratungsangebots, mit dem landwirtschaftliche Betriebe wirksam bei einer nachhaltigen Entwicklung unterstützt werden können. Wichtiges Novum ist der Weg der freiwilligen, selbstbestimmten Betriebsentwicklung zu mehr Nachhaltigkeit in Abgrenzung zu von außen kommenden Richtlinien

    Statistical Epistasis and Functional Brain Imaging Support a Role of Voltage-Gated Potassium Channels in Human Memory

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    Despite the current progress in high-throughput, dense genome scans, a major portion of complex traits' heritability still remains unexplained, a phenomenon commonly termed “missing heritability.” The negligence of analytical approaches accounting for gene-gene interaction effects, such as statistical epistasis, is probably central to this phenomenon. Here we performed a comprehensive two-way SNP interaction analysis of human episodic memory, which is a heritable complex trait, and focused on 120 genes known to show differential, memory-related expression patterns in rat hippocampus. Functional magnetic resonance imaging was also used to capture genotype-dependent differences in memory-related brain activity. A significant, episodic memory-related interaction between two markers located in potassium channel genes (KCNB2 and KCNH5) was observed (Pnominal combined = 0.000001). The epistatic interaction was robust, as it was significant in a screening (Pnominal = 0.0000012) and in a replication sample (Pnominal = 0.01). Finally, we found genotype-dependent activity differences in the parahippocampal gyrus (Pnominal = 0.001) supporting the behavioral genetics finding. Our results demonstrate the importance of analytical approaches that go beyond single marker statistics of complex traits
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