• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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

Applying SQ3R Reading Guidance Mechanism for Improving English Reading Comprehension

Hsieh, Zong-Han 28 July 2011 (has links)
Mobile devices are more and more popular in recent years. As a result, many educational applications were developed to support learning activities on mobile devices. The portability of e-book readers allows learners to read anytime and anywhere they like to read. Because of these features, an e-book reader can be an ideal reading environment for supporting learners¡¦ reading activities. However, there is still a lack of proper instructional designs for making an e-book reader such a reading environment. In this study, we integrated the reading strategy of SQ3R into the reading environment of e-book readers to support learners¡¦ reading processes. Earlier studies showed that SQ3R is an effective strategy to improve learners¡¦ reading comprehension. But we have to consider whether learners are able to follow the steps of SQ3R when they are new to this strategy. If learners were not aware of the reading strategy when reading, the effect of applying SQ3R would be limited. Therefore, we proposed a SQ3R guiding mechanism to support every stage of SQ3R and embedded it into the reading environment of e-book readers. Learners could follow the guidance of SQ3R to read effectively and improve reading comprehension. A quasi-experiment and survey were conducted to evaluate the effect of the SQ3R guiding mechanism. The results showed that, given no guidance, there was no significant difference in learners¡¦ reading comprehension scores whether they read with SQ3R or not. However, if the SQ3R reading strategy was implemented together with the guiding mechanism, this combination of guidance and strategy positively and significantly contributed to learners¡¦ reading comprehension. Relevant issues and future research to improve this study was then suggested.
2

On Derailment-Worthiness in Rail Vehicle Design : Analysis of vehicle features influencing derailment processes and consequences

Brabie, Dan January 2007 (has links)
This thesis aims at systematically studying the possibilities of minimizing devastating consequences of high-speed rail vehicle derailments by appropriate measures and features in the train design including the running gear. Firstly, an empirical database is established containing as much relevant information as possible of past incidents and accidents that have occurred at substantial running speeds due to mechanical failure close to the interface between the running gear and the track. Other causes that ultimately brought the train in a derailed condition are also covered. Although various accidental circumstances make each derailment a unique event, certain patterns appear to emerge which lead to several critical vehicle parameters capable of influencing the outcome of a derailment or preventing a derailment to occur. Secondly, the possibility of preventing wheel climbing derailments after an axle journal failure is studied by implementing mechanical restrictions between wheelsets and bogie frame. In this respect, a multi body system (MBS) computer model is developed to account for such an axle failure condition, which is successfully validated on the basis of two authentic passenger car events. In order to study the overall post-derailment vehicle behaviour, in particular the wheelsets’ vertical motion and lateral deviation on sleepers, a comprehensive MBS post-derailment module is developed and implemented in the commercially available software GENSYS. The model detects wheel-sleeper impact conditions and applies valid force resultants calculated through linear interpolation based on a pre-defined look-up table. The table was constructed through exhaustive finite element (FE) wheel to concrete sleeper impact simulations utilising the commercially available software LS-DYNA. The MBS post-derailment module has been validated successfully in several stages, including a correct prediction of the derailing wheelset’s trajectory over ten consecutive sleepers in comparison with an authentic passenger vehicle derailment event. An extensive simulation analysis on the feasibility of utilizing alternative substitute guidance mechanisms attached to the running gear on rail vehicles is presented, as means of minimizing the lateral deviation. Three low-reaching guidance mechanisms attached onto the running gear (bogie frame, brake disc and axle journal box) are analysed in terms of geometrical parameters for a successful engagement with the rail in order to prevent large lateral deviations after twelve different derailment scenarios. Three conventional coupled passenger trailing cars are investigated in terms of lateral deviation and vehicle overturning tendency after derailments on tangent and curved track. This is performed as a function of various vehicle design features and parameters such as: maximum centre coupler yaw angle, carbody height of centre of gravity, coupler height and additional running gear features. In a similar manner, the articulated train concept is investigated in terms of the post-derailment vehicle behaviour as a function of different inter-carbody damper characteristics and running gear features. / QC 20100701

Page generated in 0.0469 seconds