• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 4
  • 2
  • Tagged with
  • 7
  • 7
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

A Structural Equation Analysis of Florida Journey to Work Characteristics Using Aggregate Census 2000 Data

Challa, Srikalyan 09 April 2004 (has links)
The need for a better understanding of journey to work behavior has never before been so important. Many transportation corridors are functioning at unacceptable levels of service and many at times to their capacity. This phenomenon is more pronounced during peak period when majority of the population is making their work trip. This research builds on the recent developments in structural equations modeling technique for identifying the socio-demographic influences on the commute behavior of the population in Florida. Towards this purpose a series of five structural equations models are estimated using aggregate level data from Census 2000. Each of these models has a set of journey to work characteristics that are observed for their behavior against prevalent sociodemographic characteristics. The journey to work characteristics identified are exhaustively studied for various relationships to the socio-demographic characteristics. The model estimation led to the identification of relations between various journey to work characteristics and the socio-demographic characteristics at the Census Tract level. Some of the results obtained supported other studies performed earlier. It is hoped that the findings of this research would broaden the horizon in understanding journey to work behavior of the population of Florida.
2

Validation of the WAM-model over the Baltic Sea

Berg, Caroline January 2008 (has links)
<p>In order to understand how waves influence the exchange of momentum, latent heat and other parameters, between the ocean surface and the atmosphere, one can use models. A coupling between a wave model and an atmospheric regional climate model, for the Baltic Sea, will be performed at the Meteorology Institute in Uppsala University. The wave model is a state of the art, third generation wave model called WAM.</p><p>The new version of the WAM model (cycle 4) needs to be validated. The aim of this thesis is to perform this validation and also to investigate what meteorological forcing one should use to achieve best results. Two different types of forcing are analyzed, ERA40 reanalysis and the RCA climate model. In order to do this, observations from six different buoys in the Baltic Sea will be compared with the model output from WAM. The parameters that will be compared in this study are significant wave height, direction and peak period.</p><p>A consistent phenomenon for all the buoys is a slightly overestimation by the model of what the rate of this increases with increasing wave height. If one compares the model output when WAM are forced with the RCA climate model and when it is forced with ERA40 reanalysis, the differences between them are notable but not large. ERA40 is slightly better.</p><p>Significant wave height is quite good and gives a reasonably result. Some buoys and periods are better and some are worse. There are some differences for the significant wave height between the east coast and the west coast of Sweden, when forcing the model with RCA. It is slightly better on the west coast. On the contrary, the results from ERA40 are very coherent. The quality of the hindcast for the direction and the peak period, in contrast to the significant wave height, is not that good. The results are not bad, but it only gives a rough picture of the sea state.</p>
3

Estudo de agitação, correntes induzidas por ondas e balanço sedimentar da região do Porto de Tubarão e Praia de Camburi, Vitória/ES / Study of wave clima, wave induced currents and sedimentary balance in the region of the region of the Tubarão harbour, Vitória-ES

Marquez, André Lanfer 03 February 2010 (has links)
Os ambientes costeiros podem ser caracterizados por sua grade dinâmica, onde existe o embate entre o continente e o mar. A dinâmica sedimentar da linha de costa constitui conhecimento básico em obras de engenharia e na compreensão do ambiente costeiro. Buscou-se compreender os mecanismos do funcionamento dinâmico da região em torno do Porto de Tubarão, Vitória-ES, através de análises de marés, de clima de ondas, agitação marítima, de correntes induzidas por ondas e transporte sedimentar. Os resultados permitiram algumas interpretações tanto de curtíssimo prazo como de longo prazo. As correntes de marés são particularmente importantes, sobretudo próximo as bocas dos canais de Vitória e da Passagem atingindo valores de até 0,.7m/s. As ondas atingem a área com alturas significativas variadas, dependendo do grau de exposição. Na praia de Camburi as ondas dificilmente ultrapassam 1 metro de altura significativa, enquanto na praia Mole ondas de 2.5m de altura significativa ocorrem com certa freqüência. A direção da corrente na praia Mole está diretamente relacionadas com as direções de incidência das ondas variando de NE até SW, enquanto sua intensidade está relacionada com as alturas e períodos, variando de 0 até 0.44 m/s. A praia de Camburi, por sua vez apresenta correntes rumo ENE independente da direção de propagação das ondas ao largo da Baia do Espírito Santo. As velocidades médias variam entre 0 e 0,3 m/s. O porto de tubarão serve de abrigo às ondas, influenciando na direção média do fluxo de energia nas praias adjacentes. A longo prazo a tendência da praia de Camburi é de sofrer uma rotação acentuando os processos erosivos na porção ocidental. / The coastal zones can be characterized by the huge dynamic battle, continent forces against the ocean forces. The sedimentary dynamic of the coast line is a basic knowledge necessary to carry out engineering features and to understand the natural coastal environment. This work tried to understand the mechanisms that control those dynamics in the region near to the Tubarão Harbour, Vitória- ES. The effects of the tides, wind generated wave clima, wave induced currents and sedimentary transport was analyzed in short and long terms. In short terms, tide currents are specially important near the estuaries mouth (Vitória and Passagem channels), with velocities reaching 0.7m/s. The waves reach the coast line with different significant wave heights, depending on the each site expositions to in coming waves. At Cambury beach the waves hardly gets significant wave height over 1meter, in other hand, at Mole beach, waves with 2,5m significant wave height are quite often. At Mole beach, wave induced currents directions are directly correlated with the wave direction in outside zones, oscillating between NE and SW directions. The current velocities, which depends on wave height and wave period, presents values between 0 and 0,44 m/s. At Cambury beach the currents always goes to ENE, independent of outside wave directions. The velocities varies between 0 and 0,3 m/s. The Tubarão harbour acts like a wall creating shadows for the incident waves in the beaches behind. In long terms, the Mole beach seems to be stable and Cambury Beach seems to rotate some degrees of it mean direction, with the intensifications of the erosional process in the oriental portion of the beach.
4

Validation of the WAM-model over the Baltic Sea

Berg, Caroline January 2008 (has links)
In order to understand how waves influence the exchange of momentum, latent heat and other parameters, between the ocean surface and the atmosphere, one can use models. A coupling between a wave model and an atmospheric regional climate model, for the Baltic Sea, will be performed at the Meteorology Institute in Uppsala University. The wave model is a state of the art, third generation wave model called WAM. The new version of the WAM model (cycle 4) needs to be validated. The aim of this thesis is to perform this validation and also to investigate what meteorological forcing one should use to achieve best results. Two different types of forcing are analyzed, ERA40 reanalysis and the RCA climate model. In order to do this, observations from six different buoys in the Baltic Sea will be compared with the model output from WAM. The parameters that will be compared in this study are significant wave height, direction and peak period. A consistent phenomenon for all the buoys is a slightly overestimation by the model of what the rate of this increases with increasing wave height. If one compares the model output when WAM are forced with the RCA climate model and when it is forced with ERA40 reanalysis, the differences between them are notable but not large. ERA40 is slightly better. Significant wave height is quite good and gives a reasonably result. Some buoys and periods are better and some are worse. There are some differences for the significant wave height between the east coast and the west coast of Sweden, when forcing the model with RCA. It is slightly better on the west coast. On the contrary, the results from ERA40 are very coherent. The quality of the hindcast for the direction and the peak period, in contrast to the significant wave height, is not that good. The results are not bad, but it only gives a rough picture of the sea state.
5

Estudo de agitação, correntes induzidas por ondas e balanço sedimentar da região do Porto de Tubarão e Praia de Camburi, Vitória/ES / Study of wave clima, wave induced currents and sedimentary balance in the region of the region of the Tubarão harbour, Vitória-ES

André Lanfer Marquez 03 February 2010 (has links)
Os ambientes costeiros podem ser caracterizados por sua grade dinâmica, onde existe o embate entre o continente e o mar. A dinâmica sedimentar da linha de costa constitui conhecimento básico em obras de engenharia e na compreensão do ambiente costeiro. Buscou-se compreender os mecanismos do funcionamento dinâmico da região em torno do Porto de Tubarão, Vitória-ES, através de análises de marés, de clima de ondas, agitação marítima, de correntes induzidas por ondas e transporte sedimentar. Os resultados permitiram algumas interpretações tanto de curtíssimo prazo como de longo prazo. As correntes de marés são particularmente importantes, sobretudo próximo as bocas dos canais de Vitória e da Passagem atingindo valores de até 0,.7m/s. As ondas atingem a área com alturas significativas variadas, dependendo do grau de exposição. Na praia de Camburi as ondas dificilmente ultrapassam 1 metro de altura significativa, enquanto na praia Mole ondas de 2.5m de altura significativa ocorrem com certa freqüência. A direção da corrente na praia Mole está diretamente relacionadas com as direções de incidência das ondas variando de NE até SW, enquanto sua intensidade está relacionada com as alturas e períodos, variando de 0 até 0.44 m/s. A praia de Camburi, por sua vez apresenta correntes rumo ENE independente da direção de propagação das ondas ao largo da Baia do Espírito Santo. As velocidades médias variam entre 0 e 0,3 m/s. O porto de tubarão serve de abrigo às ondas, influenciando na direção média do fluxo de energia nas praias adjacentes. A longo prazo a tendência da praia de Camburi é de sofrer uma rotação acentuando os processos erosivos na porção ocidental. / The coastal zones can be characterized by the huge dynamic battle, continent forces against the ocean forces. The sedimentary dynamic of the coast line is a basic knowledge necessary to carry out engineering features and to understand the natural coastal environment. This work tried to understand the mechanisms that control those dynamics in the region near to the Tubarão Harbour, Vitória- ES. The effects of the tides, wind generated wave clima, wave induced currents and sedimentary transport was analyzed in short and long terms. In short terms, tide currents are specially important near the estuaries mouth (Vitória and Passagem channels), with velocities reaching 0.7m/s. The waves reach the coast line with different significant wave heights, depending on the each site expositions to in coming waves. At Cambury beach the waves hardly gets significant wave height over 1meter, in other hand, at Mole beach, waves with 2,5m significant wave height are quite often. At Mole beach, wave induced currents directions are directly correlated with the wave direction in outside zones, oscillating between NE and SW directions. The current velocities, which depends on wave height and wave period, presents values between 0 and 0,44 m/s. At Cambury beach the currents always goes to ENE, independent of outside wave directions. The velocities varies between 0 and 0,3 m/s. The Tubarão harbour acts like a wall creating shadows for the incident waves in the beaches behind. In long terms, the Mole beach seems to be stable and Cambury Beach seems to rotate some degrees of it mean direction, with the intensifications of the erosional process in the oriental portion of the beach.
6

Positional differences of physical peak intense periods in Swedish elite football : A pilot study of under 19 and first team players / Positionsskillnader vid den mest fysiskt intensiva perioden i svensk elitfotboll : En pilotstudie av ungdomsspelare och seniorspelare

Eriksson, Adam January 2024 (has links)
Syfte: Syftet med denna studie är att med hjälp av multivariata parametrar undersöka skillnader i fysisk extern belastning under den mest intensiva perioden (MIP) av match för spelare på ungdomselit och seniornivå samt att identifiera eventuella skillnader mellan positioner och halvlekar.Metod: En kvantitativ retrospektiv studie tillämpades, där spelare från ett seniorlag (SEN)spelandes i högsta divisionen i Sverige samt fotbollsspelare från ett ungdomselitlag (U19)från samma klubb spelades i näst högsta divisionen för åldersgruppen deltog i studien. Fysisk extern belastning mättes med hjälp av Global Positioning System (GPS). MIP analyserades utifrån spelares taktiska utgångsposition och med hjälp av multivariata parametrar. Rullande medelvärden användes för analys av 1-min MIP.Resultat: SEN täckte signifikant längre distans under den mest intensiva 1-mintusperioden av match jämfört med U19 (SEN 140 ± 22,3 m; U19 120 ± 24,1 m, p &lt; 0.001). Vid jämförelse mellan positioner täcker SEN-Lateral längre distanser än U19-Lateral under mest intensiva 1-mintusperioden av MIP-kinematik (135 ± 23.5 m vs 104 ± 40.3 m, p = 0.015).Slutsats: Sammanfattningsvis konfirmerar denna studie en skillnad av den mest intensiva 1-minuters perioden för senior- och ungdomsspelare för MIPk. Studien visar att seniorspelare positionerade lateral på planen täcker längre distanser under MIPk jämfört med U19 på samma position. Praktiker bör beakta dessa skillnader i sina träningsupplägg för att kunna förbereda ungdomsspelare för de fysiska krav som ses i seniormiljön / Aim: The present study aimed to investigate differences in physical external load during the most intense period (MIP) of match play for youth and senior player and to indentify possible differences between positions and halves, with multivariate parameters. Method: A quantitative retrospective study was applied, players from a senior team playing in the highest division in Sweden participated in the study as well as football players from a youth elite team from the same club playing in the second highest division for the age group. Physical external load was measured using Global Positioning System (GPS). MIP was analyzed based on players' initial tactical position and using multivariate parameters. Rolling averages were used to analyze 1-min MIP.Results: SEN covered significantly longer distances during the most intense 1-min period of the match compared to U19 (SEN 140 ± 22,3 m; U19 120 ± 24,1 m, p &lt; 0.001). When comparing between positions, SEN-Lateral covers longer distances than U19-Lateral during the most intense 1-minute period of the MIPk (135 ± 23.5 m vs 104 ± 40.3 m, p = 0.015).Conclusions: In conclusion, this study confirms a difference in the most intense 1-minute period for senior and youth players for MIPk. The study shows that senior players positioned laterally on the pitch cover longer distances during MIPk compared to U19-Lateral. Practitioners should consider these differences in their training programmes in order to prepare youth players for the physical demands seen in the senior environment.
7

Ocean Waves Estimation : An Artificial Intelligence Approach

Ramberg, Andreas January 2017 (has links)
This thesis aims to solve the mathematical inverse problem of characterizing sea waves based on the responses obtained from a marine vessel sailing under certain sea conditions. By researching this problem the thesis contributes to the marine industry by improving products that are using ocean behavior for controlling ship's dynamics. Knowledge about the current state of the sea, such as the wave frequency and height, is important for navigation, control, and for the safety of a vessel. This information can be retrieved from specialized weather reports. However, such information is not at all time possible to obtain during a voyage, and if so usually comes with a certain delay. Therefore this thesis seeks solutions that can estimate on-line the waves' state using methods in the field of Artificial Intelligence. The specific investigation methods are Transfer Functions augmented with Genetic Algorithm, Artificial Neural Networks and Case-Based Reasoning. These methods have been configured and validated using the n-fold cross validation method. All the methods have been tested with an actual implementation. The algorithms have been trained with data acquired from a marine simulation program developed in Simulink. The methods have also been trained and tested using monitored data acquired from an actual ship sailing on the Baltic Sea as well as wave data obtained from a buoy located nearby the vessel's route. The proposed methods have been compared with state-of-the art reports in order evaluate the novelty of the research and its potential applications in industry. The results in this thesis show that the proposed methods can in fact be used for solving the inverse problem. It was also found that among the investigated methods it is the Transfer Function augmented with Genetic Algorithm which yields best results. This Master Thesis is conducted under the Master of Engineering Program in Robotics at Mälardalens högskola in Västerås, Sweden. The thesis was proposed by Q-TAGG R&amp;D AB in Västerås, Sweden, a company which specializes in marine vessel dynamics research.

Page generated in 0.0623 seconds