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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.
161

Evaluation of the Performance of Three Satellite Precipitation Products over Africa

Serrat-Capdevila, Aleix, Merino, Manuel, Valdes, Juan, Durcik, Matej 13 October 2016 (has links)
We present an evaluation of daily estimates from three near real-time quasi-global Satellite Precipitation Products-Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA), Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), and Climate Prediction Center (CPC) Morphing Technique (CMORPH)-over the African continent, using the Global Precipitation Climatology Project one Degree Day (GPCP-1dd) as a reference dataset for years 2001 to 2013. Different types of errors are characterized for each season as a function of spatial classifications (latitudinal bands, climatic zones and topography) and in relationship with the main rain-producing mechanisms in the continent: the Intertropical Convergence Zone (ITCZ) and the East African Monsoon. A bias correction of the satellite estimates is applied using a probability density function (pdf) matching approach, with a bias analysis as a function of rain intensity, season and latitude. The effects of bias correction on different error terms are analyzed, showing an almost elimination of the mean and variance terms in most of the cases. While raw estimates of TMPA show higher efficiency, all products have similar efficiencies after bias correction. PERSIANN consistently shows the smallest median errors when it correctly detects precipitation events. The areas with smallest relative errors and other performance measures follow the position of the ITCZ oscillating seasonally over the equator, illustrating the close relationship between satellite estimates and rainfall regime.
162

Analysis of bounded distance decoding for Reed Solomon codes

Babalola, Oluwaseyi Paul January 2017 (has links)
Masters Report A report submitted in ful llment of the requirements for the degree of Master of Science (50/50) in the Centre for Telecommunication Access and Services (CeTAS) School of Electrical and Information Engineering Faculty of Engineering and the Built Environment February 2017 / Bounded distance decoding of Reed Solomon (RS) codes involves nding a unique codeword if there is at least one codeword within the given distance. A corrupted message having errors that is less than or equal to half the minimum distance cor- responds to a unique codeword, and therefore will decode errors correctly using the minimum distance decoder. However, increasing the decoding radius to be slightly higher than half of the minimum distance may result in multiple codewords within the Hamming sphere. The list decoding and syndrome extension methods provide a maximum error correcting capability whereby the radius of the Hamming ball can be extended for low rate RS codes. In this research, we study the probability of having unique codewords for (7; k) RS codes when the decoding radius is increased from the error correcting capability t to t + 1. Simulation results show a signi cant e ect of the code rates on the probability of having unique codewords. It also shows that the probability of having unique codeword for low rate codes is close to one. / MT2017
163

A theory of human error caussation in structural design: error predition & control via the soft system approach

Adegoke, Israel Oludotun January 2016 (has links)
No description available.
164

Decodificação do português (L2) falado por estrangeiros ingleses e americanos / Decodification of Portuguese (L2) spoken by English and American foreigners

Gallego, Maria do Rosário Montes 10 March 2009 (has links)
Nesta tese, avaliam-se as dificuldades de uso das nomonalizações em português segunda língua (L2) expressas por estrangeiros falantes do inglês (L1) e suas devidas implicações nas áreas de Morfologia, Sintaxe e Semântica. Nela apresentase a teoria da análise contrastiva (AC) e cria-se uma tabela de correspondências entre a interlíngua (I) e a língua portuguesa (L2), considerando os errors e mistakes devidos aos fenômenos da transferência e interferência através do método indutivo. Para tanto, tomaram-se por apoio os conceitos teóricos de transferência, interferência, erro e norma, entre outros. O trabalho apresenta-se dividido em duas partes: uma teórica, a análise contrastiva a priori, em que se estabelecem semelhanças e diferenças entre o inglês e o português: outra prática, a análise contrastiva a posteriori, em que se estudam as formas correspondentes da interlíngua (I) e da L2 detectando as razões das falhas e suas possíveis causas Comprovados os problemas das nominalizações, acrescentam-se, ao final da tese, algumas sugestões pedagógicas, com vistas ao ensino-aprendizagem de português para estrangeiros. / In this thesis, the difficulties related to the use of Portuguese nominalizations, expressed by English-speaking foreigners, are evalued considering the respective areas of Morphology, Syntax and Semantics. First a Contrastive Analysis (CA) theory is presented and afterwards a table of correspondences between Interlanguage (I) and Portuguese (L2 ) is created, taking into account the presence of mistakes and errors due to the transference and interference phenomena by means of an inductive process. Consequently it was based on the theoretical concepts of transference, interference and norm, among others. The work is divided into two parts: a theoretical one which is established by a contrastive analysis a priori discussing the similarities and main differences between English and Portuguese. Then, comes other part a practical one where the corresponding forms of the Interlanguage and L2) are studied and followed by the inferences of failures and probable reasons underlying them. After confirming the nominalization problems, some pedagogical suggestions were added to facilitate the Learning of Portuguese as a second language.
165

Error propagation analysis for remotely sensed aboveground biomass

Alboabidallah, Ahmed Hussein Hamdullah January 2018 (has links)
Above-Ground Biomass (AGB) assessment using remote sensing has been an active area of research since the 1970s. However, improvements in the reported accuracy of wide scale studies remain relatively small. Therefore, there is a need to improve error analysis to answer the question: Why is AGB assessment accuracy still under doubt? This project aimed to develop and implement a systematic quantitative methodology to analyse the uncertainty of remotely sensed AGB, including all perceptible error types and reducing the associated costs and computational effort required in comparison to conventional methods. An accuracy prediction tool was designed based on previous study inputs and their outcome accuracy. The methodology used included training a neural network tool to emulate human decision making for the optimal trade-off between cost and accuracy for forest biomass surveys. The training samples were based on outputs from a number of previous biomass surveys, including 64 optical data based studies, 62 Lidar data based studies, 100 Radar data based studies, and 50 combined data studies. The tool showed promising convergent results of medium production ability. However, it might take many years until enough studies will be published to provide sufficient samples for accurate predictions. To provide field data for the next steps, 38 plots within six sites were scanned with a Leica ScanStation P20 terrestrial laser scanner. The Terrestrial Laser Scanning (TLS) data analysis used existing techniques such as 3D voxels and applied allometric equations, alongside exploring new features such as non-plane voxel layers, parent-child relationships between layers and skeletonising tree branches to speed up the overall processing time. The results were two maps for each plot, a tree trunk map and branch map. An error analysis tool was designed to work on three stages. Stage 1 uses a Taylor method to propagate errors from remote sensing data for the products that were used as direct inputs to the biomass assessment process. Stage 2 applies a Monte Carlo method to propagate errors from the direct remote sensing and field inputs to the mathematical model. Stage 3 includes generating an error estimation model that is trained based on the error behaviour of the training samples. The tool was applied to four biomass assessment scenarios, and the results show that the relative error of AGB represented by the RMSE of the model fitting was high (20-35% of the AGB) in spite of the relatively high correlation coefficients. About 65% of the RMSE is due to the remote sensing and field data errors, with the remaining 35% due to the ill-defined relationship between the remote sensing data and AGB. The error component that has the largest influence was the remote sensing error (50-60% of the propagated error), with both the spatial and spectral error components having a clear influence on the total error. The influence of field data errors was close to the remote sensing data errors (40-50% of the propagated error) and its spatial and non-spatial Overall, the study successfully traced the errors and applied certainty-scenarios using the software tool designed for this purpose. The applied novel approach allowed for a relatively fast solution when mapping errors outside the fieldwork areas.
166

Castability Control in Metal Casting via Fluidity Measures: Application of Error Analysis to Variations in Fluidity Testing

Dewhirst, Brian A 16 December 2008 (has links)
"Tautologically, castability is a critical requirement in any casting process. The two most important factors impacting castability are the susceptibility of a metal to hot tearing and the degree of casting fluidity a material possesses. This work concerns itself with fluidity of molten metal. Since experimental investigations into casting fluidity began, researchers have sought to maximize fluidity through superheat, mold temperature, alloy chemistry, melt cleanliness, and mold design. Researchers who have examined the published results in the field have remarked on the difficulty of making quantitative comparisons and drawing conclusions from the data. Ragone developed a horizontal vacuum fluidity apparatus and an analytical expression for fluid length to help resolve these issues. This was expanded on by Flemings et al. Still, the comparison of results is complicated by experimental uncertainties and a plurality of experimental procedures. This work seeks to resolve these issues through an analysis of experimental uncertainties present in existing fluidity tests and the development of an improved test and procedure which is very precise, accurate, and reliable. Certain existing tests and software packages have been shown to be unsuitable for quantitative fluidity measurement. Expressions for experimental uncertainty in fluidity testing have been derived. The capability to predict variations in fluidity as a function of alloy chemistry and other variables whose range of values are intrinsic to the economics of the process will help to more accurately determine the superheat needed for successful castings and will in turn lead to a decrease in scrap rates. This will enable metal casters to more reliably cast thin sections, and to reduce cycle time or scrap rate to achieve productivity goals. Superheat was shown to remain the dominant factor in fluidity, but the test allowed investigation of alloy modifications within an alloy specification in this alloy system. Factors known to have negative effects on structural properties were found often to have neutral or positive impacts on fluidity. A deep understanding of variations in fluidity measurements is the next necessary step in a century-long quest to understand how best to make metal castings through the use of fluidity experiments."
167

On asymptotic analysis and error bounds in optimization. / CUHK electronic theses & dissertations collection

January 2001 (has links)
He Yiran. / Includes index. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (p. 74-80) and index.. / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Mode of access: World Wide Web. / Abstracts in English and Chinese.
168

Development of a computer program to simulate a noncoherent FSK system in the presence of multipath fading

Bareiss, Loren D January 2010 (has links)
Photocopy of typescript. / Digitized by Kansas Correctional Industries
169

Decodificação do português (L2) falado por estrangeiros ingleses e americanos / Decodification of Portuguese (L2) spoken by English and American foreigners

Maria do Rosário Montes Gallego 10 March 2009 (has links)
Nesta tese, avaliam-se as dificuldades de uso das nomonalizações em português segunda língua (L2) expressas por estrangeiros falantes do inglês (L1) e suas devidas implicações nas áreas de Morfologia, Sintaxe e Semântica. Nela apresentase a teoria da análise contrastiva (AC) e cria-se uma tabela de correspondências entre a interlíngua (I) e a língua portuguesa (L2), considerando os errors e mistakes devidos aos fenômenos da transferência e interferência através do método indutivo. Para tanto, tomaram-se por apoio os conceitos teóricos de transferência, interferência, erro e norma, entre outros. O trabalho apresenta-se dividido em duas partes: uma teórica, a análise contrastiva a priori, em que se estabelecem semelhanças e diferenças entre o inglês e o português: outra prática, a análise contrastiva a posteriori, em que se estudam as formas correspondentes da interlíngua (I) e da L2 detectando as razões das falhas e suas possíveis causas Comprovados os problemas das nominalizações, acrescentam-se, ao final da tese, algumas sugestões pedagógicas, com vistas ao ensino-aprendizagem de português para estrangeiros. / In this thesis, the difficulties related to the use of Portuguese nominalizations, expressed by English-speaking foreigners, are evalued considering the respective areas of Morphology, Syntax and Semantics. First a Contrastive Analysis (CA) theory is presented and afterwards a table of correspondences between Interlanguage (I) and Portuguese (L2 ) is created, taking into account the presence of mistakes and errors due to the transference and interference phenomena by means of an inductive process. Consequently it was based on the theoretical concepts of transference, interference and norm, among others. The work is divided into two parts: a theoretical one which is established by a contrastive analysis a priori discussing the similarities and main differences between English and Portuguese. Then, comes other part a practical one where the corresponding forms of the Interlanguage and L2) are studied and followed by the inferences of failures and probable reasons underlying them. After confirming the nominalization problems, some pedagogical suggestions were added to facilitate the Learning of Portuguese as a second language.
170

Utility of an Error Analysis and Performance Deficit Assessment for Selecting Brief Interventions to Increase Math Fluency

Denison, Aaron John 01 May 2013 (has links)
The purpose of this study was to examine the utility of a brief assessment for the selection of an effective instruction to increase fluency performance on computation math problems. Participants were four general education third-grade students who performed below the median score on a classwide administered multiple math skills probe. Students first participated in a brief assessment within a mini-withdrawal design to compare the relative effects of a contingent reward (CR) condition to a baseline condition on math fluency performance using a multiple skills probe. All four students increased performance when given an opportunity to earn an incentive for meeting a performance goal. Increased performance indicated a performance deficit to explain low math performance and that the students would positively respond to a contingent reward intervention on single math skills. To validate this hypothesis, the effects of baseline, CR, and instruction plus CR on fluency performance over time was assessed using a multiple baseline design across three single target skills for each student. Of the 12 skills assessed, results from the extended analysis demonstrated that the CR was effective on one skill, instruction plus CR was effective on five skills, and performance improved during baseline on six skills. Post results showed improved performance on the multiple probe for all students but performance was retained over 2 to 4 weeks on 5 of the 12 skills mastered during the study. Discussion focuses on considerations of the utility of a brief assessment approach in the application decision making and for future research

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