• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 31
  • 7
  • 5
  • 3
  • 1
  • Tagged with
  • 69
  • 25
  • 21
  • 19
  • 14
  • 10
  • 9
  • 9
  • 9
  • 8
  • 8
  • 8
  • 7
  • 7
  • 6
  • 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.
11

Measurement of Freeway Traffic Flow Quality Using GPS-Equipped Vehicles

Ko, Joonho 07 July 2006 (has links)
The evaluation of freeway service quality is crucial work, and thus, transportation professionals have developed numerous measures including traffic volume, speed, and density. However, recent research efforts have indicated that such traditional measures may not fully reflect the quality of roadway service from the perspective of individual drivers, necessitating the development of alternative approaches that complement or replace the current service quality measures. As an alternative approach, the speed variation of a vehicle has been suggested as a promising indicator of traffic flow quality perceived by individual drivers. In particular, acceleration noise, defined by the standard deviation of the acceleration of a vehicle, has been often studied as a measure of the degree of speed variation. However, previous studies have been limited to the experimental level due to the difficulty in collecting high-resolution vehicle speed profiles for computing acceleration noise. In this dissertation, the characteristics of speed variation, measured by acceleration noise, are investigated using the rich set of GPS data collected from the instrumented vehicles driven by the participants of the Commute Atlanta research program. The employment of the real-world vehicle activity data, composed of every second of vehicle operation, renders this research effort unique and provides an opportunity to investigate the various aspects of acceleration noise in the real-world context. The investigation is performed by relating acceleration noise to its three influential factors: traffic conditions, roadway, and driver/vehicles. In addition, a fuzzy inference system-based methodology, combining vehicle speed and acceleration noise from instrumented vehicles, is proposed as an approach to evaluating traffic flow quality.
12

The Performance Evaluation of Freeway Toll Stations

Cheng, Ming-hui 02 September 2005 (has links)
none
13

An application of artificial neural networks in freeway incident detection

Weerasuriya, Sujeeva A. 01 January 1998 (has links)
Non-recurring congestion caused by incidents is a major source of traffic delay in freeway systems. With the objective of reducing these traffic delays, traffic operation managers are focusing on detecting incident conditions and dispatching emergency management teams to the scene quickly. During the past few decades, a few number of conventional algorithms and artificial neural network models were proposed to automate the process of detecting incident conditions on freeways. These algorithms and models, known as automatic incident detection methods (AIDM), have experienced a varying degree of detection capability. Of these AIDMs, artificial neural network-based approaches have illustrated better detection performance than the conventional approaches such as filtering techniques, decision tree method, and catastrophe theory. So far, a few neural network model structures have been tested to detect freeway incidents. Since the freeway incidents directly affect the freeway traffic flow, majority of these models have used only traffic flow variables as model inputs. However, changes in traffic flow may also be stimulated by the other features (e.g., freeway geometry) to a greater extent. Many AIDMs have also used a conventional detection rate as a performance measure to assess the detection capability. Yet the principle function of incident detection model, which is to identify whether an incident condition exists for a given traffic pattern, is not measured in its entirety by this conventional measure. In this study, new input feature sets, including freeway geometry information, were proposed for freeway incident detection. Sixteen different artificial neural network (ANN) models based on feed forward and recurrent architectures with a variety of input feature sets were developed. ANN models with single and double hidden layers were investigated for incident detection performance. A modified form of a conventional detection rate was introduced to capture full capability of AIDMs in detecting incident patterns in the freeway traffic flow. Results of this study suggest that double hidden layer networks are better than single hidden layer networks. The study has demonstrated the potential of ANNs to improve the reliability using double layer networks when freeway geometric information is included in the model.
14

Avaliação do espaço funcional livre em pacientes com alterações funcionais do sistema estomatognatico tratados com aparelhos de superficie oclusal plana

Santos, Sidney Saint'Clair 08 August 2004 (has links)
Orientador: Wilkens Aurelio Buarque e Silva / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-08-04T00:58:55Z (GMT). No. of bitstreams: 1 Santos_SidneySaint'Clair_D.pdf: 775564 bytes, checksum: 3773083a765391d32e47600112182852 (MD5) Previous issue date: 2004 / Resumo: O objetivo deste trabalho foi avaliar o espaço funcional livre e as modificações na posição da mandíbula, no plano sagital (ântero-posterior) e no plano frontal látero-lateral), utilizando a eletrognatografia computadorizada (K6-I Diagnostic System, Myotronics Co, U.S.A.), em pacientes portadores de alterações funcionais do sistema estomatognático, tratados com aparelhos de superfície oclusal plana modificados (com guias em incisivos e caninos). A amostra aleatória foi composta por 15 pacientes submetidos aos exames previstos na ficha clínica do CETASE (Centro de Estudos e Tratamento das Alterações do Sistema Estomatognático) para a confirmação das variáveis para inclusão e para exclusão na amostra, dentre elas os portadores de alterações degenerativas. As avaliações foram realizadas antes da instalação dos aparelhos, com 30, 60, 90 e 120 dias após a instalação dos mesmos. Os resultados mostraram que o espaço funcional livre teve aumento significativo em função do tempo de tratamento / Abstract: The aim of this research was to evaluate changes in the mandible position, in sagittal plane (anteroposterior) and in frontal plane, using computerized electrognathography (K6-I Diagnostic System, Myotronics Co, U.S.A.) in patients who suffer from functional changes in the stomatognathic system, treated with modified flat occlusal surface appliances (guidances on incisors and canines). The random sample was composed of 15 patients submitted to examinations foreseen on the CETASE (Center of Studies and Treatment of stomatognathic System Alterations) history chart, to confirm variables for inclusion and for exclusion on the sample, including patients suffering from degenerative changes. The evaluations were taken before the appliances were set and within 30,60,90 and 120 days after. The results showed that the free-way space had an statistically significant difference higher on behalf of time treatment / Doutorado / Protese Dental / Doutor em Clínica Odontológica
15

Best HCM deterministic model calibrated for capacity analysis of basic segments of freeways in Lima

Cubas Gonzales, Tania Lizeth, Rondon Alcedo, Rousbel Ricardo, Tarquino Torres, Fernando Mauricio 30 September 2020 (has links)
El texto completo de este trabajo no está disponible en el Repositorio Académico UPC por restricciones de la casa editorial donde ha sido publicado. / In traffic engineering, the assessment of capacity in basic segment of freeway is a critical factor for planning, design and operational analysis of the freeway facilities. Thereby, the Highway Capacity Manual - HCM is the main guide used in many countries of the world including Perú that contain the methodology to estimate freeway capacity in traffic studies. Nevertheless, the information of vehicular traffic used for the construction of the models proposed by the HCM, reflect the characteristics of North American features. Therefore, its application in other traffic conditions, must be backed by studies of the local conditions and calibrations of the models proposed, hereby, adjusting to each city. The objetive of this research, is calibrate and compare of the HCM 2010 and HCM 2016 models, starting off the traffic engineering study in Panamericana Sur freeway located in Lima, Perú. The report will recommended the application of a calibrated model that best represents the local Peruvian conditions. The results of this study suggest that the model of calibrated capacity HCM2016, is the best representation, with a reliability of 97%, the local behavior of the basic freeway segments in function of the speed and the flow intensity. After applying the calibrated model into basic freeway segments concessioned by Rutas de Lima SAC, it was reflected that the use of the HCM2000, employed by this Company, show flow intensities within a level of service - LOS D, while, the calibrated HCM2016 shows us that those values are found, in reality, within a level of service - LOS E.
16

Traffic characteristics on the Jeddah-Makkah freeway, Saudi Arabia

Osra, Khalid A. January 2002 (has links)
No description available.
17

Development of a simulation model for freeway weaving sections /

Zarean, Mohsen January 1987 (has links)
No description available.
18

An Analysis of Traffic Behavior at Freeway Diverge Sections using Traffic Microsimulation Software

Kehoe, Nicholas Paul 12 July 2011 (has links)
Microscopic simulation traffic models are widely used by transportation researchers and practitioners to evaluate and plan for transportation facilities. The intent of these models is to estimate the second-by-second vehicle movements and interactions on such facilities. Due to constraints related to time, budget, and availability of data, these models are typically designed in such a way where the microscopic output is viewed on the macroscopic level. Inherently, this can leave uncertainty to how the model estimates the individual interactions between vehicles on the microscopic level. This thesis utilizes three microsimulation models, INTEGRATION, VISSIM, and CORSIM, to investigate the lane changing behavior as vehicles approach a freeway diverge area. The count of lane changes, lane use distribution, and visual inspection of the simulated lane changing behavior was compared to video data collected at two freeway diverge areas on U.S. 460 in the vicinity of Blacksburg, Virginia during both off-peak and peak periods. It was observed that all three models generally overestimated the number of lane changes near the diverge areas compared to field observations. By modifying the models' lane changing logic, the models were able to closely match field observations in one of the four scenarios. It was found that microsimulation models accurately estimated the lane use distribution. In addition, the INTEGRATION lane use distribution results were found to be more consistent when compared to observed lane use distribution than either VISSIM or CORSIM. / Master of Science
19

Transportation policies and quality of life an analysis of the socioeconomic effects of implementing Ramp Metering, High Occupancy Vehicle (HOV) Lanes and High Occupancy (HOT) Lanes within an urban transportation network /

Jefferson, Katherine D. January 2008 (has links)
Thesis (Ph.D.)--George Mason University, 2008. / Vita: p. 199. Thesis director: Roger Stough. Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Public Policy. Title from PDF t.p. (viewed Mar. 16. 2009). Includes bibliographical references (p. 182-198). Also issued in print.
20

An assessment of the South African government's Gauteng Freeway Improvement Project (GFIP) toll road strategy

Gabriel, Cassandra C 20 August 2012 (has links)
The South African government has decided to introduce an extensive toll road system in the Gauteng Province, to fund the road upgrades in the Gauteng Freeway Improvement Project (GFIP). This research report assesses the effectiveness of this funding strategy by analysing the social, economic and environmental impact of the GFIP toll road. The user pay principle is also interrogated to assess the fairness of the toll tariffs to be levied on different user groups. This study has found that the GFIP investment was an unstrategic investment in transport infrastructure. It is proposed that an integrated multi-modal transport strategy is developed, that prioritises the development of the railway system for freight cargo and public transport. As freight vehicles cause more than 99% of roads damage, it is proposed that toll tariffs are only applied to freight vehicles, to lessen the negative social impact of tolling. It is proposed that an independent transport regulator and a consumer council are established, to protect consumer interests, to ensure the independent review of toll tariffs, and to review future public-funded transport investments.

Page generated in 0.0137 seconds