The main aim of the thesis is to assess the origin of surge phenomena, primarily surge waves at the weir pool Střekov, using the selected methodology. The paper is divided into several parts. There is a brief introduction to the problematics and research of possible solution methods, followed by a verification of these methods on a physical model and finally an application of a numerical method for an assessment of the chosen locality.

For vehicles equipped with electric motors there exist a possibility to recuperate energy during deceleration. This master’s thesis presents a driver support function, a Predictive Deceleration Control (PDC), that warns the driver when to release the accelerator pedal. If the driver follows the instructions from the function the vehicle will decelerate to an appropriate speed at the upcoming road feature, such as a roundabout. The function should both improve energy consumption and enhance driver comfort. This master’s thesis focused on how such a function can be implemented and a proof of concept was designed in a Matlab/Simulink environment. Within the scope of the proof of concept the function should warn the driver to release the accelerator pedal ahead of roundabouts, intersections, speed limit signs and stop signs. With the help of map information and the vehicle most probable path, the distance to the road features could be determined and the predicted braking distance to these road features could be calculated by the function. A feedforward controller was used to control the deceleration phase and was based on a longitudinal vehicle model. The PDC was tested both in a Lynk & Co 01 and CEVT’s dynamic simulator and the results proved that the function can be implemented in for example a Lynk & Co 01 without any additional hardware needed. However, it requires software that can provide the function with map information. During the tests performed during the master’s thesis, map information was acquired with a frequency of 1 Hz, but for the function to become more robust a higher update frequency is required. / För fordon utrustade med elektriska motorer finns det möjlighet till att återvinna energi under inbromsning. Det här examensarbetet presenterar ett förarhjälpmedel som varnar förare när denna ska släppa accelerationspedalen. Om föraren följer uppmaningen kommer bilen att minska hastigheten till en lämplig ingångshastighet för kommande vägobjekt, till exempel en cirkulationsplats. Funktionen ska både förbättra energiförbrukningen och öka förarstödet. Det här examensarbetet fokuserade på hur en sådan funktion kan implementeras och ett exempel på koncept utvecklades i en Matlab/Simulink miljö. Under utvecklingen av funktionen skulle den prediktiva retardationsregle- ringen varna förare att släppa accelerationspedalen innan cirkulationsplatser, korsningar, hastighetsskyltar och stoppskyltar. Men hjälp av kartdata och fordonets mest troliga väg kunde distansen till nästa vägobjekt bestämmas och den förväntade retardationsdistansen beräknas. Dessa värden användes sedan för att bestämma när föraren ska varnas. Framkopplingsreglering användes för att reglera retardationsförloppet och baserades på en longitudinell fordonsmodell. Den utvecklade funktionen testades både i en Lynk & Co 01 och CEVT:s dynamiska simulator och resultaten visade att funktionen kan implementeras i till exempel en Lynk & Co 01 utan någon extra hårdvara. Dock kräver en implementation av funktionen mjukvara som kan bistå funktionen med kartdata och mest trolig väg för fordonet. Under de utförda testerna i bil samlades kartdata och bilens position in med en frekvens av 1 Hz, men för att funktionens tillförlitlighet ska öka krävs en högre uppdateringsfrekvens.

Collision avoidance systems (CASs) are being developed and fielded to reduce the number and severity of rear-end crashes. Kinematic algorithms within CASs evaluate sensor input and apply assumptions describing human-response timing and deceleration to determine when an alert should be presented. This dissertation presents an analytic assessment of dynamic function and performance CASs and associated driver performance for preventing automotive rear-end crashes. A method for using naturalistic data in the evaluation of CAS algorithms is described and applied to three algorithms. Time-series parametric data collected during 13 rear-end crashes and 70 near-crashes are input into models of collision avoidance algorithms to determine when the alerts would have occurred. Algorithm performance is measured by estimating how much of the driving population would be able to respond in the time available between when an alert would occur and when braking was needed. A sensitivity analysis was performed to consider the effect of alternative inputs into the assessment method. The algorithms were found to warn in sufficient time to permit 50–70% of the population to avoid collision in similar scenarios. However, the accuracy of this estimate was limited because the tested algorithms were found to alert too frequently to be feasible. The response of the assessment method was most sensitive to differences in assumed response-time distributions and assumed driver braking levels. Low-speed crashes were not addressed by two of the algorithms. Analysis of the events revealed that the necessary avoidance deceleration based on kinematics was generally less than 2 s in duration. At the time of driver response, the time remaining to avoid collision using a 0.5g average deceleration ranged from â 1.1 s to 2.1 s. In 10 of 13 crashes, no driver response deceleration was present. Mean deceleration for the 70 near-crashes was 0.37g and maximum was 0.72g. A set of the events was developed to measure driver response time. The mean driver response time was 0.7 s to begin braking and 1.1 s to reach maximum deceleration. Implications for collision countermeasures are considered, response-time results are compared to previous distributions and future work is discussed. / Ph. D.

This thesis describes the development of a new experimental technique for studying tunable-collision-energy, quantum state-selected, low-temperature ion-molecule reactions. This has been achieved through the combination of a Stark decelerator for neutral dipolar molecules, and a linear Paul ion trap. The Stark deceleration process for ND₃ was examined in detail, through the analysis of experimental data in combination with newly written molecular dynamics simulation programs. In order to prepare a sample of molecules appropriate for collision studies, additional beamline components were introduced after the decelerator. These components were: two hexapoles, to provide transverse focussing, maximising the molecular density; a molecular buncher, providing increased longitudinal velocity resolution; and a fast-opening shutter, to separate decelerated molecules from undecelerated molecules. The sympathetic-cooling of Xe⁺ ions and ND⁺₃ ions by laser-cooled, Coulomb crystallised ⁴⁰Ca⁺ ions with the ion trap was also studied. In particular, the stable trapping of Xe⁺ was demonstrated for the first time, and the experimental developments that led to this are discussed. The work in this thesis represents significant progress towards studying the reaction of tunable-energy ND₃ in the |j,mk> = |1,−1> quantum state with cold Xe⁺ ions. Ion-molecule reactions utilising ND₃ molecules electrostatically guided through the Stark decelerator were performed. It was observed that the main source of error in these experiments was in the calculation of the initial number of Xe⁺ ions that had been sympathetically cooled into the Coulomb crystal. The sensitivity of the crystal morphology to the number of Xe⁺ ions was evaluated using molecular dynamics simulations. Strategies have been developed to reduce this uncertainty in future studies. In addition to experimental work, the theory of low temperature ion-molecule reactions has been developed further. The temperature at which classical and quantum mechanical calculations diverge due to purely statistical effects has been investigated using different model intermolecular potentials, for closed-shell and open-shell species, and in the ground and rotationally excited states. From the results of these calculations, several promising candidate reactions have been suggested that might exhibit statistical quantum behaviour at experimentally achievable temperatures.

Šiame darbe yra analizuojama kelių eismo saugumo situacija ir avaringumo veiksniai remiantis statistika ir užsienio šalių mokslininkų tyrimais. Tiriamajame darbe taip pat pateikiami taikomos avaringumo nustatymo metodikos trūkumai ir pasiūlymai. Darbe yra keletas tyrimo objektų. Atliktas vizualinis Vilniaus miesto eismo reguliavimo ir organizavimo sistemos tyrimas nustatant pagrindines problemas ir „juodųjų dėmių“ analizė nustatant pagrindinius didesnio avaringumo faktorius. Siekiant nustatyti kelio nuolydžio įtaką eismo saugumui buvo atliktas stabdymo automobiliu tyrimas įvertinant lėtėjimo pagreičio kitimą priklausomai nuo vertikalių kelio nelygumų. Darbą sudaro įvadas ir 5 aiškinamojo rašto skyriai, pabaigoje pateikiamos išvados ir pasiūlymai. / This research analyses the situation of road traffic safety and factors in traffic accidents based on statistic and studies of foreign scientists. Research also represents weaknesses of actual accident methodology and proposals. There are few objects of investigation. Visual research is made by assessing the main problems of traffic regulation and organization system in Vilnius city and “black spots” analysis identifying factors of increased accident rate. Car braking investigation was performed by pursuing to estimate the alternation of deceleration in roads with vertical gradient influence to traffic safety. Research consists of introduction, 5 descriptive parts, summarized giving conclusions and proposals.

No description available.

Diploma thesis Selected measurements of the motion of bicycles – braking and ridein the curve analyses problematic manoeuvres of bicycle riders according to the most typical accidents including bikes. There will be given statistics of bikers´ participation on accident amount that happened within last few years. The measurements of bicycles moving around bands of specific radiuses as a situation of most bicycle accidents will be described in the next part of this thesis. There will be also specified the values of average bicycle speeds when driving in curves with various radiuses according to types of bicycles, sex and experiences of the riders and will be an output of this thesis. Further on there will be measurements of braking in the direct line on various surfaces with different types of bikes and different brakes used.

The diploma thesis Cyclists speed analysis at the age bracket of 4 to 10 deals with history and origin of bicycle, description and types of the contruction of bicycles for children at the age bracket mentioned above. The thesis includes the statistics of accidents involving cyclists and regulations providing for the ride on a bicycle on a carriageway. The practical part includes measuring cyclists speed when passing a measured section and the analysis of these data. The analysis of data is processed in terms of gear systems as the equipment. Complementary measuring was made in a slight rising. In the second part of the practical part is measured braking of cyclists at a particular age bracket and the evaluation of their deceleration. The conclusion includes comparison with measuring of other authors made so far.

Title: Solar Wind Modification in the Earth Foreshock Author: Jaroslav Urbář Department: Department of Surface and Plasma Science Supervisor: Prof. Zdeněk Němeček, Department of Surface and Plasma Science Abstract: The thesis presents statistical studies of the solar wind deceleration and deflection in the foreshock and its potential causes. The multi-point observa- tions from the THEMIS mission in the foreshock are compared with a Wind solar wind monitor with motivation to estimate different factors influencing evolution of solar wind speed and its deflection. We have found a systematic deceleration of the solar wind mainly due to its proton component with a decreasing distance to the bow shock that is controlled by the compressibility and the level of magnetic field fluctuations in the ULF wave range associated with the flux of reflected and accelerated particles. We can conclude that the reflected particles excite waves of large amplitudes that decelerate the solar wind protons throughout the foreshock as well as in front of the Moon. Keywords: Earth foreshock; reflected protons; solar wind proton velocity recon- struction; deceleration; ULF waves 1

[pt] A experiência fundamental da sociedade moderna é a de uma intensa aceleração do fluxo de experiência de cada indivíduo (ROSA, 2019a). Os reflexos deste fenômeno são observados em larga escala, coexistindo com um discurso cultural que relaciona a velocidade a limitações sociais, ambientais e individuais. Frente a isso, nota-se o surgimento de movimentos contestatórios à lógica temporal moderna, utilizados como válvulas de escape em relação à aceleração (BAUER et al, 2015; HUSEMANN e ECKHARDT, 2019; LEVINE, 2015; ROSA, 2019a), dentre os quais o Slow Movement (HONORE, 2019; PARKINS, 2004). Neste contexto, este estudo propõe compreender o processo de desaceleração do consumidor no ambiente estrutural contemporâneo, por meio do consumo sob o rótulo Slow. Como a noção de temporalidade está relacionada ao desdobramento de significados que emergem das práticas de vida, utiliza-se a Sociossemiótica (LANDOWSKI, 2014a) como aporte teórico-metodológico para entender a criação de sentido e os significados da desaceleração em torno do consumo Slow. Com base em entrevistas em profundidade com consumidores do Movimento Slow, foi possível concluir que este tipo de consumo pode equivaler a uma experiência extraordinária de lentificação, revelando-se como oásis de desaceleração (ROSA, 2019a) em meio ao contexto contemporâneo acelerado. Este extraordinário possui a estesia como elemento central, emergindo a partir da busca dos consumidores por sentido no que e em como consomem, da combinação de elementos estruturais e antiestruturais e do emprego de estratégias de desaceleração específicas. / [en] A critical experience of modern society involves an intense acceleration of experience flux of each individual (ROSA, 2019a). The consequences of this phenomenon are observed in a large scale, coexisting with a cultural discourse that relates speed to social, environmental and individual limitations. In view of this, movements have emerged contesting the modern temporal logic, used as escape valves from acceleration (BAUER et al., 2015; HUSEMANN and ECKHARDT, 2019; LEVINE, 2015; ROSA, 2019a), including the Slow Movement (HONORE, 2019; PARKINS, 2004). This study seeks to understand the process of consumer deceleration in the contemporary structural environment, assessing Slow Movement consumption. As the notion of temporality is related to the development of meanings that emerge from life practices, Sociosemiotics (LANDOWSKI, 2014a) is used as a theoretical-methodological approach to understand the creation of sense and meanings from deceleration via slow consumption. Based on in-depth interviews conducted with Slow Movement consumers it was possible to conclude that such type of consumption can ensure an extraordinary experience of deceleration, acting as an oasis of deceleration (ROSA, 2019a) in the fast-paced contemporary context. This extraordinary experience has esthesia as its central element, emerging from the search of consumers for meaning in what and how they consume, the combination of structural and anti-structural elements, and the use of specific deceleration strategies.