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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.
671

Acquisition of Hebrew Noun Plurals in Early Immersion and Bilingual Education

Yunger, Robyn Rebecca 01 January 2011 (has links)
This study examined the acquisition of Hebrew noun plurals in early immersion and bilingual education by focusing on performance, as well as morpho-syntactic and semantic errors in inflecting nouns. A total of 196 students from Senior Kindergarten (n = 86) and grades 1 (n = 58) and 2 (n = 53) were administered measures of inflectional morphology in Hebrew. Results indicated that children applied high frequency, salient, simple to apply inflectional patterns involving male-female nouns, as well as the basic way of noting plurality. Two major obstacles in the pluralisation of Hebrew nouns were suffix regularity and stem transparency. Error analysis revealed three categories of responses: rule-based, analogy-based and non-strategic errors. The principal conclusion was that errors notwithstanding, young children learning Hebrew as a foreign language are moving toward an understanding of plural formation. The development of morpho-syntactic structures gradually develops over time and with exposure to Hebrew instruction.
672

Estimating Wind Forecast Errors and Quantifying Its Impact on System Operations Subject to Optimal Dispatch

Li, Xiaoguang 14 December 2011 (has links)
Wind power is being added to the supply mix of numerous jurisdictions, and an increasing level of uncertainties will be the new reality for many system operators. Accurately estimating these uncertainties and properly analyzing their effects will be very important to the reliable operation of the grid. A method is proposed to use historical wind speed, power, and forecast data to estimate the potential future forecast errors. The method uses the weather conditions and ramp events to improve the accuracy of the estimation. A bilevel programming technique is proposed to quantify the effects of the estimated uncertainties. It improves upon existing methods by modeling the transmission network and the re-dispatch of the generators by operators. The technique is tested with multiple systems to illustrate the feasibility of using this technique to alert system operators to potential problems during operation.
673

Energy-based Error Control Strategies Suitable for Long MD Simulations

Easley, Kante 31 December 2010 (has links)
When evaluating integration schemes used in molecular dynamics (MD) simulations, energy conservation is often cited as the primary criterion by which the integrators should be com- pared. As a result variable stepsize Runge-Kutta methods are often ruled out of consideration due to their characteristic energy drift. We have shown that by appropriately modifying the stepsize selection strategy in a variable stepsize RK method it is possible for the MD practitioner to obtain substantial control over the energy drift during the course of a simulation. This ability has been previously unreported in the literature, and we present numerical examples to illustrate that it can be achieved without sacrificing computational efficiency under currently obtainable timescales.
674

Acquisition of Hebrew Noun Plurals in Early Immersion and Bilingual Education

Yunger, Robyn Rebecca 01 January 2011 (has links)
This study examined the acquisition of Hebrew noun plurals in early immersion and bilingual education by focusing on performance, as well as morpho-syntactic and semantic errors in inflecting nouns. A total of 196 students from Senior Kindergarten (n = 86) and grades 1 (n = 58) and 2 (n = 53) were administered measures of inflectional morphology in Hebrew. Results indicated that children applied high frequency, salient, simple to apply inflectional patterns involving male-female nouns, as well as the basic way of noting plurality. Two major obstacles in the pluralisation of Hebrew nouns were suffix regularity and stem transparency. Error analysis revealed three categories of responses: rule-based, analogy-based and non-strategic errors. The principal conclusion was that errors notwithstanding, young children learning Hebrew as a foreign language are moving toward an understanding of plural formation. The development of morpho-syntactic structures gradually develops over time and with exposure to Hebrew instruction.
675

Estimating Wind Forecast Errors and Quantifying Its Impact on System Operations Subject to Optimal Dispatch

Li, Xiaoguang 14 December 2011 (has links)
Wind power is being added to the supply mix of numerous jurisdictions, and an increasing level of uncertainties will be the new reality for many system operators. Accurately estimating these uncertainties and properly analyzing their effects will be very important to the reliable operation of the grid. A method is proposed to use historical wind speed, power, and forecast data to estimate the potential future forecast errors. The method uses the weather conditions and ramp events to improve the accuracy of the estimation. A bilevel programming technique is proposed to quantify the effects of the estimated uncertainties. It improves upon existing methods by modeling the transmission network and the re-dispatch of the generators by operators. The technique is tested with multiple systems to illustrate the feasibility of using this technique to alert system operators to potential problems during operation.
676

Hardware implementation of daubechies wavelet transforms using folded AIQ mapping

Islam, Md Ashraful 22 September 2010
The Discrete Wavelet Transform (DWT) is a popular tool in the field of image and video compression applications. Because of its multi-resolution representation capability, the DWT has been used effectively in applications such as transient signal analysis, computer vision, texture analysis, cell detection, and image compression. Daubechies wavelets are one of the popular transforms in the wavelet family. Daubechies filters provide excellent spatial and spectral locality-properties which make them useful in image compression.<p> In this thesis, we present an efficient implementation of a shared hardware core to compute two 8-point Daubechies wavelet transforms. The architecture is based on a new two-level folded mapping technique, an improved version of the Algebraic Integer Quantization (AIQ). The scheme is developed on the factorization and decomposition of the transform coefficients that exploits the symmetrical and wrapping structure of the matrices. The proposed architecture is parallel, pipelined, and multiplexed. Compared to existing designs, the proposed scheme reduces significantly the hardware cost, critical path delay and power consumption with a higher throughput rate.<p> Later, we have briefly presented a new mapping scheme to error-freely compute the Daubechies-8 tap wavelet transform, which is the next transform of Daubechies-6 in the Daubechies wavelet series. The multidimensional technique maps the irrational transformation basis coefficients with integers and results in considerable reduction in hardware and power consumption, and significant improvement in image reconstruction quality.
677

Error control for scalable image and video coding

Kuang, Tianbo 24 November 2003
Scalable image and video has been proposed to transmit image and video signals over lossy networks, such as the Internet and wireless networks. However, scalability alone is not a complete solution since there is a conflict between the unequal importance of the scalable bit stream and the agnostic nature of packet losses in the network. This thesis investigates three methods to combat the detrimental effects of random packet losses to scalable images and video, namely the error resilient method, the error concealment method, and the unequal error protection method within the joint source-channel coding framework. For the error resilient method, an optimal bit allocation algorithm is proposed without considering the distortion caused by packet losses. The allocation algorithm is then extended to accommodate packet losses. For the error concealment method, a simple temporal error concealment mechanism is designed to work for video signals. For the unequal error protection method, the optimal protection allocation problem is formulated and solved. These methods are tested on the wavelet-based Set Partitioning in Hierarchical Trees(SPIHT) scalable image coder. Performance gains and losses in lossy and lossless environments are studied for both the original coder and the error-controlled coders. The results show performance advantages of all three methods over the original SPIHT coder. Particularly, the unequal error protection method and error concealment method are promising for future Internet/wireless image and video transmission, because the former has very good performance even at heavy packet loss (a PSNR of 22.00 dB has been seen at nearly 60% packet loss) and the latter does not introduce any extra overhead.
678

Micro-Simulation of the Roundabout at Idrottsparken Using Aimsun : A Case Study of Idrottsparken Roundabout in Norrköping, Sweden

Septarina, Septarina January 2012 (has links)
Microscopic traffic simulation is useful tool in analysing traffic and estimating the capacity and level of service of road networks. In this thesis, the four legged Idrottsparken roundabout in the city of Norrkoping in Sweden is analysed by using the microscopic traffic simulation package AIMSUN. For this purpose, data regarding traffic flow counts, travel times and queue lengths were collected for three consecutive weekdays during both the morning and afternoon peak periods. The data were then used in model building for simulation of traffic of the roundabout. The Root Mean Square Error (RMSE) method is used to get the optimal parameter value between queue length and travel time data and validation of travel time data are carried out to obtain the basic model which represents the existing condition of the system. Afterward, the results of the new models were evaluated and compared to the results of a SUMO model for the same scenario model. Based on calibrated and validated model, three alternative scenarios were simulated and analysed to improve efficiency of traffic network in the roundabout. The three scenarios includes: (1) add one free right turn in the north and east sections; (2) add one free right turn in the east and south sections; and (3) addition of one lane in roundabout. The analysis of these scenarios shows that the first and second scenario are only able to reduce the queue length and travel time in two or three legs, while the third scenario is not able to improve the performance of the roundabout. In this research, it can be concluded that the first scenario is considered as the best scenario compared to the second scenario and the third scenario. The comparison between AIMSUN and SUMO for the same scenario shows that the results have no significance differences. In calibration process, to get the optimal parameter values between the model measurements and the field measurements, both of AIMSUN and SUMO uses two significantly influencing parametersfor queue and travel time. AIMSUN package uses parameter of driver reaction time and the maximum acceleration, while SUMO package uses parameter of driver imperfection and also the driver rection time.
679

Error control for scalable image and video coding

Kuang, Tianbo 24 November 2003 (has links)
Scalable image and video has been proposed to transmit image and video signals over lossy networks, such as the Internet and wireless networks. However, scalability alone is not a complete solution since there is a conflict between the unequal importance of the scalable bit stream and the agnostic nature of packet losses in the network. This thesis investigates three methods to combat the detrimental effects of random packet losses to scalable images and video, namely the error resilient method, the error concealment method, and the unequal error protection method within the joint source-channel coding framework. For the error resilient method, an optimal bit allocation algorithm is proposed without considering the distortion caused by packet losses. The allocation algorithm is then extended to accommodate packet losses. For the error concealment method, a simple temporal error concealment mechanism is designed to work for video signals. For the unequal error protection method, the optimal protection allocation problem is formulated and solved. These methods are tested on the wavelet-based Set Partitioning in Hierarchical Trees(SPIHT) scalable image coder. Performance gains and losses in lossy and lossless environments are studied for both the original coder and the error-controlled coders. The results show performance advantages of all three methods over the original SPIHT coder. Particularly, the unequal error protection method and error concealment method are promising for future Internet/wireless image and video transmission, because the former has very good performance even at heavy packet loss (a PSNR of 22.00 dB has been seen at nearly 60% packet loss) and the latter does not introduce any extra overhead.
680

Examining Performance Monitoring in Attention Deficit Hyperactivity Disorder

Payne, Shalaine 11 December 2009 (has links)
Behavioural symptoms, cognitive deficits, and findings from electrophysiological, neuroimaging and genetic studies all suggest atypical performance monitoring in ADHD. Performance monitoring involves error detection and post-error behavioural adjustment and is crucial to behavioural self-regulation and reinforcement learning, both of which are dysfunctional in ADHD. Therefore, post-error slowing was examined in children with ADHD and controls using a modified flanker task both with, and without, error detection provided. There was a significant main effect of group on post-error slowing across conditions and when error-detection was provided, significant post-error slowing deficits were found in children with ADHD. These findings suggest that the performance monitoring deficit in ADHD is specific to post-error behavioural adjustment and supports the inclusion of this deficit in the neurocognitive profile of ADHD. Findings are discussed in terms of current neurocognitive reinforcement learning models of ADHD.

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