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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Přestavba křižovatky Pisárecká – Veslařská v Brně / Reconstruction of crossing Pisárecká - Veslařská, Brno

Tejkal, David January 2015 (has links)
The main reason of doing this master thesis is reconstruction crossroad Pisarecka – Veslarska in Brno with growing traffic intensity up every year. Obviously had to be observed the best safety draw around the walking and bicycle area. This crossroad is using like transfer place. The result of this work is to elaborate of the situation including charasteristic cut sections and longitudinal profile of main road. Part of this work is an estimate of the financial cost to realize this building.
92

Mikrosimulace dopravního proudu při liniovém řízení. / Traffic flow microsimulation in line management.

Mlčková, Ivana January 2016 (has links)
The main task of this thesis is to verify the line management of traffic. A microsimulation model of traffic was made in program for traffic simulation called Aimsun. The data from radar measuring have been processed and then put into the model. Some of parameters in model were adapted to meet the reality on the road. Finally, there have been suggested more suggestions in this model and the efficiency of the solutions was evaluated.
93

Optimización del Comportamiento Operacional de una Intersección Tipo Trébol aplicando Semaforización Inteligente con la Metodología Ramp Metering / Optimization of the Operational Behavior of a Cloverleaf Applying Smart Traffic Lights with the Ramp Metering Methodology

Cutipa Luque, John Peter, Lozano Laffore, Edson 10 December 2020 (has links)
Los tréboles son infraestructuras diseñadas para mejorar la circulación y seguridad vehicular en las intersecciones. El trébol analizado se define como una intersección vial a desnivel parcial de tres lazos y cuatro ramales directos; el cual, está comprendido por la vía expresa metropolitana Javier Prado y la vía expresa nacional Panamericana. Esta investigación se realizó mediante un análisis de riesgo donde se obtuvo un nivel de riesgo intolerable identificado en los conductores que invaden las vías adyacentes; los cuales, interrumpen el flujo vehicular y pueden ocasionar colisiones. Además, se identificó problemas en su comportamiento operacional, especialmente en los lazos que confluyen con las vías principales. Esto debido al ingreso desordenado de vehículos, inadecuada dosificación vehicular y maniobras peligrosas realizadas por los conductores que tratan de ingresar a la via principal. La presente investigación propone un sistema de semaforización inteligente con la metodología Ramp metering en base al algoritmo ALINEA. El cual, ordena, mediante una dosificación vehicular en tiempo real, el ingreso de los vehículos hacía las vías principales. Además, disminuye la probabilidad de colisiones ya que aplica un control de ingreso adaptativo. La propuesta logra que la velocidad promedio se incremente en 15,8% y que los tiempos de viaje se reduzcan en un máximo de 19.1%. Adicionalmente, existe un leve incremento de 30 Veh/h en el aforo vehicular del trébol. A partir de lo observado, se demuestra que la optimización de parámetros individuales genera una sinergia que influye positivamente en el comportamiento operacional del trébol. / Clovers are infrastructures designed to improve traffic and vehicular safety at intersections. The analyzed cloverleaf is a partially uneven road intersection with three loops and four direct branches located in the Javier Prado highway and the Panamericana highway in the city of Lima. The research will base on a risk analysis with an intolerable level of risk identified in drivers who invaded adjacent roads. Interrupt the flow of vehicles and can cause chain collisions. Also, it was possible to identify problems in their operational behavior, especially in the loops that converge with the main roads. Due to the disorderly entry of vehicles, inadequate vehicle dosing, the formation of lines in cloverleaf loops, increased probability of collisions and dangerous maneuvers carried out by drivers trying to enter the main road. The present research proposes an intelligent traffic light system with the Ramp metering methodology based on the ALINEA algorithm. Which, through real-time vehicle dosing, orders the entry of vehicles onto the main roads. Besides, it reduces the probability of collisions since it applies adaptive entry control. The research achieves an increased by 15.8% in the average speed, and a maximum of 19.1% reduces that travel times. Additionally, there is a slight increase of 30 Veh / h in clover's vehicle capacity. Furthermore, it shows that the optimization of individual parameters generates a synergy that positively influences the operational behavior of the clover. / Tesis
94

LIGHTING STRATEGIES FOR NIGHTTIME CONSTRUCTION AND MAINTENANCE ACTIVITIES ON ROADWAYS

Franklin Vargas Davila (12466701) 27 April 2022 (has links)
<p>Over the last two decades, an increasing number of highway construction and maintenance projects in the United States have been completed at night to avoid or mitigate traffic congestion delays. Working at night entails several advantages, including lower traffic volumes at night, reduced impact on local businesses, more freedom for lane closures, longer possible work hours, lower pollution, cooler temperatures for equipment and material, and fewer overall crashes due to lower traffic volumes at night. Although nighttime roadway operations may minimize traffic disruptions, there are several safety concerns for motorists passing by and for workers in the nighttime work zone. For instance, just in 2019, there were 842 work zone fatalities reported in the United States, with 48% of these being associated with fatalities on night shifts. Additionally, 70% of these fatalities involved drivers/occupants under the age of 50. Moreover, improper lighting arrangements or excessive lighting levels produced by temporary lighting systems installed at the job site could cause harmful levels of glare for the traveling public and workers leading to an increase level of hazards and crashes in the vicinity of the work zone. </p> <p>To address the issue of glare, very few studies have been conducted to evaluate and quantify glare at work zones. Most of these studies were limited to the determination of disability glare levels of lighting systems (balloon lights and light towers) with a metal-halide type light source by using the veiling luminance ratio (<em>VL ratio</em>) as a criterion for limiting disability glare. However, deeper evaluation of the effects of driver’s age on the veiling luminance ratio, and the use of energy-efficient lighting systems which employ light-emitting diode (LED) type light sources were not performed.</p> <p>This thesis focuses on determining and evaluating disability glare on nighttime work zones as a step towards developing appropriate lighting strategies for improving the safety of workers and motorists during nighttime highway construction and maintenance projects. Disability glare is the glare that impairs our vision of objects without necessarily causing discomfort and it can be evaluated using the veiling luminance ratio (<em>VL ratio</em>). In this study, disability glare values were determined by using lighting data (vertical illuminance and pavement luminance measurements) from testing 49 lighting arrangements. Two LED balloon lights, a metal-halide light tower, and an LED light tower were utilized for the field lighting experiments. The disability glare level evaluation examines the effects of mounting height, power output, rotation angle, and aiming angle of luminaires on the veiling luminance ratio values (which is a criterion for limiting disability glare). </p> <p>The analysis of the disability glare values revealed four major findings regarding the roles played by the mounting height, power output, lighting system orientation, aiming angles of luminaries, and driver’s age on disability glare levels as follows: (i) an increase in mounting heights of both balloon lights and light towers resulted in lower veiling luminance ratio values (or disability glare); (ii) compared to the "perpendicular" and "away" orientations, orienting the light towers in a "towards" direction (45 degrees) significantly increases the disability glare levels of the lighting arrangement; (iii) increasing the tilt angles of luminaires of the portable light towers resulted in an increase in veiling luminance ratio values; (iv) for balloon lights, at observers ages over 50, <em>VL ratio</em> values were found to be greater than the maximum recommended; (v) for LED light towers oriented towards the traffic, at driver’s ages over 40, <em>VL ratio</em> values exceed the Illuminating Engineering Society (IES) recommended value; and (vi) for metal-halide light towers oriented towards the traffic, at driver’s ages over 50, <em>VL ratio</em> values exceed the IES recommended value. The results from this research study can provide State Transportation Agencies (STAs) and roadway contractors with a means to improve glare control strategies for nighttime work.</p>
95

Propuesta de diseño de una intersección doble diamante modificada multimodal en el cruce de las Avenidas Salaverry-Cádiz y Jirón Huiracocha, Lima / Proposal design of a modified multimodal Diverging Diamond Interchange (DDI) in the crossing of Salaverry-Cadiz Avenue and Huiracocha Street

Morales Gálvez, Jose Carlos, Tantalean Altamirano, Kevin Stephen 08 November 2021 (has links)
La intersección de las avenidas Salaverry, Cádiz y Jirón Huiracocha, en el límite de los distritos de San Isidro y Jesús María en Lima, se le considera de gran demanda vehicular, como peatonal, en donde la ausencia de pasos peatonales y ciclovías protegidas, y congestión vehicular generan sensación de inseguridad e ineficiencia en el sistema de tránsito urbano. Debido a esto, se realizó el estudio de tráfico y se planteó una Intersección Diamante Divergente (DDI, por sus siglas en inglés) como solución a esta perspectiva. El diseño geométrico, calibración y validación se realizaron con el programa Vissim 9 en búsqueda de la más eficiente alternativa en cuanto operatividad en una DDI. Para ello se obtuvieron los datos topográficos, toma de datos y extrapolación de los flujos vehiculares existentes. La propuesta elegida no satisfizo las expectativas planteadas al inicio de la investigación, por ello se modificó la operatividad existente con la finalidad de crear un entorno urbanístico cotidiano. Una intersección con una coordinación semafórica entre ambos cruces (Avenida Cádiz y Jirón Huiracocha) genera eficiencia y seguridad a los usuarios. La primera modificación fue realizar una apertura en la Avenida Salaverry con dirección al Jirón Huiracocha, el diseño de un ciclo semafórico y la exclusividad de cruce peatonal y ciclista. Por último, en cuanto la intersección con la Avenida Cádiz, se optimizó la seguridad de las ciclovías existentes al evitar el cruce directo con las arterias viales. Con estas modificaciones, se logró mejorar el sistema en un 7% para operatividad vehicular y un 70% en cuanto a los flujos peatonales. De esto se concluye que los tiempos de viaje, demoras y longitudes de cola vehicular se reducen frente a la situación actual. Además, el flujo de todos los usuarios se desarrolla en armonía, sin elevados tiempos de espera o elevada demanda vial en ciertos tramos del caso de estudio. / The intersection of Salaverry - Cadiz Avenues and Huiracocha street, in the limits of San Isidro and Jesús María districts in Lima, is known by its vehicular and pedestrian massive demand, where the absence of protected pedestrian crossings, bicycle path and traffic congestion generate insecurity and inefficiency in the local transit system. Due to this, the traffic study was carried out by a Diverging Diamond Intersection (DDI) as an alternative to enhance these shortcomings. The geometric design, calibration and validation were developed with Vissim 9 modeling program in search of the most efficient alternative in terms of operability in a DDI, according to its traffic light cycle and geometric design. As inputs parameters were necessary topographic data, data collection and extrapolation of existing vehicle flows. The chosen proposal did not reach the expectations at the beginning of the research; therefore, the existing traffic operability was modified in order to create a daily urban environment. An intersection with coordinated traffic lights between both intersections (Cádiz-Salaverry Avenue and Huiracocha Street) generates efficiency and safety for users. The first modification was to make an opening on Salaverry Avenue in the direction of Huiracocha street, the design of a traffic light cycle and the exclusivity path of pedestrian and bicycle. Finally, regarding the intersection at Cadiz-Salaverry Avenues, the safety of the existing bicycle roads was optimized by avoiding direct crossing on these road arteries. / Tesis
96

Vyhodnocení doplňkové výbavy karoserií vozidel z pohledu legislativy / Evaluation of Complementary Car Body Equipment from the Point of View of Legislation

Knebl, Vladimír January 2012 (has links)
This thesis discusses the possibilities of additional equipment on vehicle body. The content of the theoretical and practical part. The theoretical part is focused on clarifying the fundamental concepts, including the issue of legislative regulations and laws. The practical part deals with specific examples of changes in the body, which are then examined in terms of legislation and clarify their possible assembly and conditions of use.
97

Propuesta de semaforización actuada con detección de presencia peatonal, en la intersección de la Av. Huandoy con la carretera Panamericana Norte, para reducir el tiempo de cruce peatonal y la longitud de cola vehicular / Proposal for fully actuated signal control with pedestrian presence detection, at the intersection of the Panamerican highway with Huandoy avenue, to reduce the time pedestrian crossing and the length of the vehicle queue

Jauregui Obando, Christian André, Torres Domínguez, María Donata 26 July 2021 (has links)
Un problema considerable en Lima es el congestionamiento vehicular, debido al crecimiento demográfico continuo, el centralismo, la escasa planificación urbanística y el crecimiento sostenido del parque automotor. La presente tesis se centra en la intersección de la carretera Panamericana Norte con la avenida Huandoy distrito de Los Olivos. La realidad problemática presente en la intersección es la gran variabilidad del flujo peatonal y vehicular bajo un sistema de semáforo de tiempo fijo. Por ende, la consecuencia de este tipo de semáforos aumenta los tiempos de cruce peatonal, es decir el tiempo que demoran los peatones en cruzar la vía y las longitudes de colas vehiculares. La investigación propone el diseño de un ciclo semafórico completamente actuado cuyo objetivo es captar la densidad de peatones en las islas de refugio y dar prioridad de paso de acuerdo con las necesidades del entorno. Para ello, se realizó un estudio de identificación de los volúmenes, tanto de peatones como de vehículos y en los que al realizar los flujogramas para un intervalo de 15 minutos se demostró la alta variabilidad de volúmenes presentes en una hora. El modelo de control de prioridad óptimo se simula y valida. Así mismo, se hace uso del módulo VisVAP del programa Vissim, para asignar la condicional de cruce. Finalmente. los resultados demuestran que, se redujo el tiempo de cruce peatonal en el sentido oeste a este en 6.38% y en 20.84% la longitud de cola vehicular. Además, se mejoró la geometría vial, esto permitió mayor área para la isla de refugio. / A major problem in Lima is vehicle congestion, due to continued population growth, centralism, poor urban planning and the growth of the automotive fleet. This thesis focuses on the intersection of the Panamerican highway with Huandoy avenue in the Los Olivos district. The problematic reality present at the intersection is the traffic light at fixed time as a traffic regulator. Owing to this, the system is inefficient for the great variability of pedestrian and vehicular volumes in the study area. And the consequence of this type directly prejudice pedestrian crossing times and vehicle queue lengths. The research proposes the design of a fully actuated signal control whose objective is to detect the density of pedestrian on the refuge islands and prioritize the passage according to needs of the environment. To do this, a study was carried out to identify the volumes, both of pedestrians and vehicles, and when performing the flow charts for a n interval of 15 minutes, the high variability of volumes present in one hour was demonstrated. The optimal priority control model is simulated and validated. Likewise, the VisVap module of the Vissim9 program is used to assign the crossing condition. Finally, the results show that the pedestrian crossing time was reduced by 6.38% and the length of vehicle queues by 20.84 %. In addition, the road geometry was improved, this allowed more area for the refuge island. / Tesis
98

Akcelerace výpočtu stínů a osvětlení / Shadowing and Lighting Acceleration

Milet, Tomáš January 2021 (has links)
Cílem této práce je prezentovat metody pro akceleraci výpočtů stínů a osvětlení.  Práce se zabývá akcelerací na vzorek přesných stínů pomocí stínových těles na různých platformách. Obsahem práce je také zvýšení přesnosti stínových map a zvýšení přesnosti osvětlování scény s mnoha světly.
99

The effect of using variable curing light types and intensities on the parameters of a mathematical model that predicts the depth of cure of light- activated dental composites

Ridha, Hashem January 2009 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / The purpose of this study is to further investigate the effect of using six different light source types with different light output intensities on the parameters of a mathematical model that predicts the DOC in VLDC’s. In this equation: D = Dp In(E0/Ec), D is the depth of cure in millimeters, E is the curing energy in J/cm2, Ec is the critical curing energy for the composite to reach a gel layer, and Dp is a characteristic coefficient. Three LED and three halogen dental curing units with different light output intensities were used to cure three shades (B1, A3, D3) of a hybrid resin composite. The exposure duration was at the intervals of 10, 20, 30, and 40 seconds for each sample setting. ISO scraping technique was performed to measure the depth of cure of each sample. Regression analysis was used to assess the fit of the proposed mathematical model D = Dp In(E0/Ec) to the experimental data obtained in this study. 72 For all the shade-light combinations; A3, B1, and D3 had significantly different regression lines (P < 0.05) with significantly higher Dp and Ec for B1 than A3 and D3. The only exceptions were for the Ec values between B1 and D3 in Allegro, Astralis 5, and Visilux 2 groups; and the Ec between A3 and B1 in Allegro group. The Dp and Ec parameters didn’t show significant differences between A3 and D3 shades in all the groups. Also, most of the significant differences for Dp values occurred in the B1 shade-light combinations; however, none of the D3 shade-light combinations showed significant differences for Dp. Several factors play combined influential effects on the kinetics of polymerization and depth of cure in VLDC’s. The shade has a more dominant effect on both parameters Dp and Ec than the curing light type or source output intensity. As we cure lighter shades “B1,” the effect of using different lights with different output intensities on the two parameters Dp and Ec will be greater and more significant than for darker shades “A3 or D3.” The clinical significance drawn from this study is that clinicians should recognize that using curing lights w/ increased output intensities doesn’t absolutely increase the DOC of VLDC’s especially with the darker shades.
100

A comparison of algorithms used in traffic control systems / En jämförelse av algoritmer i trafiksystem

Björck, Erik, Omstedt, Fredrik January 2018 (has links)
A challenge in today's society is to handle a large amount of vehicles traversing an intersection. Traffic lights are often used to control the traffic flow in these intersections. However, there are inefficiencies since the algorithms used to control the traffic lights do not perfectly adapt to the traffic situation. The purpose of this paper is to compare three different types of algorithms used in traffic control systems to find out how to minimize vehicle waiting times. A pretimed, a deterministic and a reinforcement learning algorithm were compared with each other. Test were conducted on a four-way intersection with various traffic demands using the program Simulation of Urban MObility (SUMO). The results showed that the deterministic algorithm performed best for all demands tested. The reinforcement learning algorithm performed better than the pretimed for low demands, but worse for varied and higher demands. The reasons behind these results are the deterministic algorithm's knowledge about vehicular movement and the negative effects the curse of dimensionality has on the training of the reinforcement learning algorithm. However, more research must be conducted to ensure that the results obtained are trustworthy in similar and different traffic situations. / En utmaning i dagens samhälle är att hantera en stor mängd fordon som kör igenom en korsning. Trafikljus används ofta för att kontrollera trafikflödena genom dessa korsningar. Det finns däremot ineffektiviteter eftersom algoritmerna som används för att kontrollera trafikljusen inte är perfekt anpassade till trafiksituationen. Syftet med denna rapport är att jämföra tre typer av algoritmer som används i trafiksystem för att undersöka hur väntetid för fordon kan minimeras. En tidsbaserad, en deterministisk och en förstärkande inlärning-algoritm jämfördes med varandra. Testerna utfördes på en fyrvägskorsning med olika trafikintensiteter med hjälp av programmet Simulation of Urban MObility (SUMO). Resultaten visade att den deterministiska algoritmen presterade bäst för alla olika trafikintensiteter. Inlärningsalgoritmen presterade bättre än den tidsbaserade på låga intensiteter, men sämre på varierande och högre intensiteter. Anledningarna bakom resultaten är att den deterministiska algoritmen har kunskap om hur fordon rör sig samt att dimensionalitetsproblem påverkar träningen av inlärningsalgoritmen negativt. Det krävs däremot mer forskning för att säkerställa att resultaten är pålitliga i liknande och annorlunda trafiksituationer.

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