Audio Signal Processing Using Time-Frequency Approaches: Coding, Classification, Fingerprinting, and Watermarking

Audio signals are information rich nonstationary signals that play an important role in our day-to-day communication, perception of environment, and entertainment. Due to its non-stationary nature, time- or frequency-only approaches are inadequate in analyzing these signals. A joint time-frequency (TF) approach would be a better choice to efficiently process these signals. In this digital era, compression, intelligent indexing for content-based retrieval, classification, and protection of digital audio content are few of the areas that encapsulate a majority of the audio signal processing applications. In this paper, we present a comprehensive array of TF methodologies that successfully address applications in all of the above mentioned areas. A TF-based audio coding scheme with novel psychoacoustics model, music classification, audio classification of environmental sounds, audio fingerprinting, and audio watermarking will be presented to demonstrate the advantages of using time-frequency approaches in analyzing and extracting information from audio signals.</p

Efficient material characterization by means of the Doppler effect in microwaves

Subject of this thesis is the efficient material characterization and defects detection by means of the Doppler effect with microwaves. The first main goal of the work is to develop a prototype of a microwave Doppler system for Non-Destructive Testing (NDT) purposes. Therefore it is necessary that the Doppler system satisfies the following requirements: non-expensive, easily integrated into industrial process, allows fast measurements. The Doppler system needs to include software for hardware control, measurements, and fast signal processing. The second main goal of the thesis is to establish and experimentally confirm possible practical applications of the Doppler system. The Doppler system consists of the following parts. The hardware part is designed in a way to ensure fast measurement and easy adjustment to the different radar types. The software part of the system contains tools for: hardware control, data acquisition, signal processing and representing data to the user. In this work firstly a new type of 2D Doppler amplitude imaging was developed and formalized. Such a technique is used to derive information about the measured object from several angles of view. In the thesis special attention was paid to the frequency analysis of the mea- sured signals as a means to improve spatial resolution of the radar. In the context of frequency analysis we present 2D Doppler frequency imaging and compare it with amplitude imaging. In the thesis the spatial resolution ability of CW radars is examined and im- proved. We show that the joint frequency and the amplitude signal processing allows to significantly increase the spatial resolution of the radar.Das Thema dieser Dissertation ist die effiziente Materialcharakterisierung und Fehlerdetektion durch Nutzung des Dopplereffektes mittels Mikrowellen. Das erste Hauptziel der Arbeit ist die Entwicklung eines Prototyps eines Mikrowellen-Doppler-Systems im Bereich der zerstörungsfreien Prüfung. Das Doppler-System muss folgenden Voraussetzungen erfüllen: es sollte preisgünstig sein, leicht in industrielle Prozesse integrierbar sein und schnelle Messungen erlauben. Das Doppler-System muss die Software für die Hardware-Kontrolle, den Messablauf und die schnelle Signalverarbeitung beinhalten. Das zweite Hauptziel der Dissertation ist es, mögliche praktische Anwendungsfelder des Doppler-Systems zu identifizieren und experimentell zu bearbeiten. Das Doppler-System besteht aus zwei Teilen. Der Hardware-Teil ist so konstruiert, dass er schnelle Messungen und leichte Anpassungen an verschiedene Sensor- und Radartypen zulässt. Der Software-Teil des Systems beinhaltet Werkzeuge für: Hardware-Kontrolle, Datenerfassung, Signalverarbeitung und Programme, um die Daten für den Benutzer zu präsentieren. In dieser Arbeit wurde zuerst ein neuer Typ der 2D-Doppler-Amplitudenbildgebung entwickelt und formalisiert. Dieser Technik wird dafür benutzt, Informationen über die gemessenen Objekte von verschiedenen Blickpunkten aus zu erhalten. In dieser Doktorarbeit wird der Frequenzanalyse der gemessenen Signale besondere Aufmerksamkeit geschenkt, um die Ortsauflösung des Radars zu verbessern. Im Kontext der Frequenzanalyse wird die 2D-Doppler-Frequenzbildgebung präsentiert und mit der Amplitudenbildgebung vergleichen. In dieser Dissertation werden die räumliche Auflösungsmöglichkeiten von CW-Radaren untersucht und verbessert. Es wird gezeigt, dass es die Frequenz- und Amplitudensignalverarbeitung erlaubt, die Ortsauflösung des Radars erheblich zu erhöhen

Crop production and global food security in relation to climate variation: an empirical analysis

The challenge of meeting increasing global food demand is amplified by climate change. Crop yield is vulnerable to extreme conditions, including heatwaves, droughts and downpours, leading to widespread concern about negative effects of climate change on food security. This thesis describes a novel empirical analysis of total production, yields and harvested area data for three major crops (wheat, maize and soybean), using a unique, global, gridded agricultural time-series data set. Trend analysis is applied to changes in production, yield and harvested area of these three crops. Machine learning is used to quantify their responses to climate. A new methodology is introduced to identify “shocks”. Results show a more complex dynamics of agricultural production than is suggested by current liter- ature. Large changes in regional production, driven by harvested area rather than yield, have been driven by policy shifts. A large “killing degree-day” sum depresses yields for some regions and crops, but enhances them in others. Heat deficits can be as deleterious as heatwaves. Shocks can be negative or positive. Production variability has increased, but major negative shocks have been few, and have not become more frequent. Production shocks have been caused as often by changes in harvested area as in yield. These findings do not support a universal negative effect of climate change on crop production. More- over, stable global food supplies will not be assured by maximizing yields. It is equally important that farmers in different countries and environments grow a variety of crops. Climate-related risk is currently concentrated in the most productive baskets, exposing the global food supply to avoidably high risk. Increasing frequencies of climate extremes in the main producing areas only make such shocks more likely. Various measures that are not directly related to climate would help to make global food supplies more resilient.Open Acces

Probabilistic and artificial intelligence modelling of drought and agricultural crop yield in Pakistan

Pakistan is a drought-prone, agricultural nation with hydro-meteorological imbalances that increase the scarcity of water resources, thus, constraining water availability and leading major risks to the agricultural productivity sector and food security. Rainfall and drought are imperative matters of consideration, both for hydrological and agricultural applications. The aim of this doctoral thesis is to advance new knowledge in designing hybridized probabilistic and artificial intelligence forecasts models for rainfall, drought and crop yield within the agricultural hubs in Pakistan. The choice of these study regions is a strategic decision, to focus on precision agriculture given the importance of rainfall and drought events on agricultural crops in socioeconomic activities of Pakistan. The outcomes of this PhD contribute to efficient modelling of seasonal rainfall, drought and crop yield to assist farmers and other stakeholders to promote more strategic decisions for better management of climate risk for agriculturalreliant nations

An AI Approach to Tasking and Control of an Industrial Laser System

Effective use of lasers for materials processing applications requires a thorough knowledge of the fundamental mechanisms governing the interaction of radiation with matter. A discussion of the highly non-linear laser-material interaction is thus presented. The research then focusses on alternative approaches to the non-linear analysis of laser material processing through the application of genetic algorithms and chaos theory. A genetic algorithm is developed which predicts the laser cutting rate with good accuracy. The theory of deterministic chaos was exploited to investigate laser cutting of stainless steel; a new fundamental understanding of the interaction via the energy phase portrait was established. The construction of the phase portrait is illustrated. The work then focusses on the actual design and implementation of a hybrid intelligent system for the tasking and control of a gas laser for materials processing. Existing artificial intelligence (AI) methodologies are reviewed. A new AI topological technique is developed to facilitate the design of a Proportional-Integral- Differential Knowledge Based Management System (PID-KBMS). The final intelligent system comprises of the PID-KBMS and a Cone Decision Support System (CDSS). The CDSS provides on-line image acquisition and analysis of the laser cutting process. The architecture of the hybrid intelligent system is illustrated. The intelligent system source code was implemented in a Microsoft Windows and UNIX XWindows environment using Borland C. The intelligent system is hosted by a Viglen 486 PC and a SUN-SPARC 4. A virtual graphical user interface is presented on the Viglen 486 via the network. A final evaluation of the investigations into: the non-linear characteristics of laser-material interactions and prediction schemes, the AI topological technique for the design of AI control engines, the design and implementation of the PID-KBMS and CDSS are presented in the concluding chapter. The algorithms and methods applied herein have general applicability to any non-linear control problem. Finally, recommendations for future research are given

Graduate Catalog/Supplement 1995-1998

Contains course descriptions, University college calendar, and college administration.https://digitalcommons.usu.edu/universitycatalogs/1040/thumbnail.jp