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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.
1

Generalized Maximally Selected Statistics

Hothorn, Torsten, Zeileis, Achim January 2007 (has links) (PDF)
Maximally selected statistics for the estimation of simple cutpoint models are embedded into a generalized conceptual framework based on conditional inference procedures. This powerful framework contains most of the published procedures in this area as special cases, such as maximally selected chi-squared and rank statistics, but also allows for direct construction of new test procedures for less standard test problems. As an application, a novel maximally selected rank statistic is derived from this framework for a censored response partitioned with respect to two ordered categorical covariates and potential interactions. This new test is employed to search for a high-risk group of rectal cancer patients treated with a neo-adjuvant chemoradiotherapy. Moreover, a new efficient algorithm for the evaluation of the asymptotic distribution for a large class of maximally selected statistics is given enabling the fast evaluation of a large number of cutpoints. / Series: Research Report Series / Department of Statistics and Mathematics
2

Permutation Tests for Structural Change

Zeileis, Achim, Hothorn, Torsten January 2006 (has links) (PDF)
The supLM test for structural change is embedded into a permutation test framework for a simple location model. The resulting conditional permutation distribution is compared to the usual (unconditional) asymptotic distribution, showing that the power of the test can be clearly improved in small samples. Furthermore, generalizations are discussed for binary and multivariate dependent variables as well as model-based permutation testing for structural change. The procedures suggested are illustrated using both artificial and real-world data (number of youth homicides, employment discrimination data, structural-change publications, and stock returns). / Series: Research Report Series / Department of Statistics and Mathematics
3

Perfect Reconstruction Filter Bank Structure Based On Interpolated FIR Filters

Cadena Pico, Jorge Eduardo 07 July 2016 (has links)
State of the art filter bank structures achieve practically perfect reconstruction with very high computational efficiency. However, the increase in computational requirements due to the need to process increasingly wider band signals is paramount. New filter bank structures that provide extra information about a signal while achieving the same level of required efficiency, and perfect reconstruction properties, need to be developed. In this work a new filter bank structure, the interpolated FIR (IFIR) filter bank is developed. Such a structure combines the concepts of filter banks, and interpolated FIR filters. The filter design procedures for the IFIR filter bank are developed and explained. The resulting structure was compared with the non-maximally-decimated filter bank (NMDFB), achieving the same performance in terms of the number of multiplications required per sample and the overall distortion introduced by the system, when operating with Nyquist prototype filters. In addition, the IFIR filter is tested in both simulated and real communication environments. Performance, in terms of bit-error-rate, was found to not be degraded significantly when using the IFIR filter bank system for transmission and reception of QPSK symbols. / Master of Science
4

VOCAL FUNCTION EXERCISES FOR NORMAL VOICE: THE EFFECTS OF MAXIMALLY SUSTAINED PHONATION

Morton, Mariah Elaine 01 January 2019 (has links)
Vocal Function Exercises (VFEs) is a well-known treatment program that consists of four exercises, in which the first and fourth tasks require maximally sustained phonation. However, the active ingredients responsible for treatment efficacy are still unknown. The primary purpose of this investigation was the explore the effects of maximally sustained phonation on the VFE outcome measure of maximum phonation time (MPT) in individuals between the ages of 18-40 with normal voice. Participants were randomized into three experimental groups that completed VFEs for six weeks. The baseline group sustained tasks one and four for as long as was achieved at the baseline session; The three-week group sustained the exercises for as long as possible the first three weeks, then to their three-week MPT average for the remaining three weeks of the program; The standard group maximally sustained phonation for all six weeks. Results indicated significant improvement in percent to MPT goal attainment in the standard group and three-week group. The baseline group did not result in significant change. Including maximally sustained phonation throughout the course of VFEs is essential to producing substantial improvements in voice production, in terms of percent to MPT goal.
5

Asymptotika v maximálně neasociativních kvazigrupách / Asymptotics in maximally nonassociative quasigroups

Bajtoš, Marek January 2021 (has links)
This thesis follows up the results of article A. Drápal a I. M. Wanless, On the number of quadratic orthomorphisms that produce maximally nonassociative quasigroups. This paper dealt with the density of maximally non-associative quasigroups of a certain cons- truction. However, certain cases had to be neglected in the calculations due to restrictive conditions. The examination of these cases is the subject of this work. It turned out that the asymptotic behavior in the general case as in the article differs from the beha- vior in cases examined in our work. In addition to the calculations themselves, the work contains a theoretical introduction with an explanation of the constructions used in the previous article, as well as our own theory necessary for our calculations. In addition, we experimentally verified our results. 1
6

Photometric Methods for Autonomous Tree Species Classification and NIR Quality Inspection

Valieva, Inna January 2015 (has links)
In this paper the brief overview of methods available for individual tree stems quality evaluation and tree species classification has been performed. The use of Near Infrared photometry based on conifer’s canopy reflectance measurement in near infrared range of spectrum has been evaluated for the use in autonomous forest harvesting. Photometric method based on the image processing of the bark pattern has been proposed to perform classification between main construction timber tree species in Scandinavia: Norway spruce (Picea abies) and Scots Pine (Pinus sylvestris). Several feature extraction algorithms have been evaluated, resulting two methods selected: Statistical Analysis using gray level co-occurrence matrix and maximally stable extremal regions feature detector. Feedforward Neural Network with Backpropagation training algorithm and Support Vector Machine classifiers have been implemented and compared. The verification of the proposed algorithm has been performed by real-time testing.
7

多語言的場景文字偵測 / Multilingual Scene Text Detection

梁苡萱, Liang, Yi Hsuan Unknown Date (has links)
影像中的文字訊息,通常包含著與場景內容相關的重要資訊,如地點、名稱、指示、警告等,因此如何有效地在影像中擷取文字區塊,進而解讀其意義,成為近來電腦視覺領域中相當受矚目的議題。然而在眾多的場景文字偵測方法裡,絕大多數是以英文為偵測目標語言,中文方面的研究相當稀少,而且辨識率遠不及英文。因此,本論文提出以中文和英文為偵測目標語言的方法,分成以下四個主要程序:一、前處理,利用雙邊濾波器(Bilateral filter)使文字區域更加穩定;二、候選文字資訊擷取,考慮文字特徵,選用Canny 邊緣偵測和最大穩定極值區域(Maximally Stable Extremal Region),分別提取文字邊緣和區域特徵,並結合兩者來優化擷取的資訊;三、文字連結,依中文字結構和直式、橫式兩種書寫方向,設置幾何條件連結候選文字字串;四、候選字串分類,以SVM加入影像中文字的特徵,分類文字字串和非文字字串。使得此方法可以偵測中文和英文兩種語言,並且達到不錯的辨識效果。 / Text messages in an image usually contain useful information related to the scene, such as location, name, direction and warning. As such, robust and efficient scene text detection has gained increasing attention in the area of computer vision recently. However, most existing scene text detection methods are devised to process Latin-based languages. For the few researches that reported the investigation of Chinese text, the detection rate was inferior to the result for English. In this thesis, we propose a multilingual scene text detection algorithm for both Chinese and English. The method comprises of four stages: 1. Preprocessing by bilateral filter to make the text region more stable. 2. Extracting candidate text edge and region using Canny edge detector and Maximally Stable Extremal Region (MSER) respectively. Then combine these two features to achieve more robust results. 3. Linking candidate characters: considering both horizontal and vertical direction, character candidates are clustered into text candidates by using geometrical constraints. 4. Classifying candidate texts using support vector machine (SVM), the text and non-text areas are separated. Experimental results show that the proposed method detects both Chinese and English texts, and achieve satisfactory performance compared to those approaches designed only for English detection.

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