• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 80
  • 52
  • 25
  • 15
  • 15
  • 8
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • Tagged with
  • 246
  • 50
  • 30
  • 30
  • 29
  • 22
  • 22
  • 20
  • 20
  • 18
  • 18
  • 15
  • 14
  • 14
  • 14
  • 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.
91

Spectro-Temporal Features For Robust Automatic Speech Recognition

Suryanarayana, Venkata K 01 1900 (has links)
The speech signal is inherently characterized by its variations in time, which get reflected as variations in frequency. The specto temporal changes are due to changes in vocaltract, intonation, co-articulation and successive articulation of different phonetic sounds. In this thesis we are looking for improving the speech recognition performance through better feature parameters using a non-stationary model of speech. One effective means of modeling a general non-stationary signal is using the AM-FM model. AM-FM model can be extended to speech through a sub-band analysis, which can be mimic the auditory analysis. In this thesis, we explore new methods for estimating AM and FM parameters based on the non-uniform samples of the signal. The non-uniform sample approach along with adaptive window estimation provides for important advantage because of multi-resolution analysis. We develop several new methods based on ZC intervals, local extrema intervals and signal derivative at ZC’s as different sample measures of the signal and explore their effectiveness for instantaneous frequency (IF) and instantaneous envelope (IE) estimation. To deal with speech signal for automatic speech recognition, we explore the use of auditory motivated spectro temporal information through the use of an auditory filter bank and signal parameters (or features) are derived from the instantaneous energy in each band using the non-linear energy operator over a larger window length. The temporal correlation present in the signal is exploited by using DCT and keeping the lower few coefficients of DCT to keep the trend in the energy in each band. The DCT coefficients from different frequency bands are concatenated together, and a further spectral decorrelation is achieved through KLT (Karhunen-Loeve Transform) of the concatenated feature vector. The changes in the vocaltract are well captured by the change in the formant structure and to emphasize these details for ASR we have defined a temporal formant by using the AM-FM decomposition of sub-band speech. A uniform wideband non-overlaping filters are used for sub-band decomposition. The temporal formant is defined using the AM-FM parameters of each subband signal. The temporal evolution of a formant is represented by the lower order DCT coefficients of the temporal formant in each band and its use for ASR is explored. To address the robustness of ASR performance to environmental noisy conditions, we have used a hybrid approach of enhancing the speech signal using statistical models of the speech and noise. Use of GMM for statistical speech enhancement has been shown to be effective. It is found that the spectro-temporal features derived from enhanced speech provide further improvement to ASR performance.
92

Radio crosses divides through sport : the role of radio in a post-apartheid South Africa, 1994-2002 : a case study on Ukhozi FM and Umhlobo Wenene FM.

Dladla, Mzwandile Mzokhona. January 2003 (has links)
This study will examine the role sport plays in a new democratic South Africa between the periods 1994-2002. Its objective is to look at how sport can be used, through the medium of radio, as a unifying activity in the diversified South African society. The study will specifically compare the broadcast of soccer and rugby on the two radio stations (Ukhozi FM and Umhlobo Wenene FM). The main aim is to explain the relevance of the inclusion of sport into the programmes of the two radio stations mentioned above, in the period 1994-2002. This comparative approach will also explain the extent to which the listeners of these stations understand the sporting codes mentioned (soccer and rugby) now compared to how they did before 1994. This study was undertaken because there is little of its kind (if any) that looks at the power of sport broadcasting on radio in changing people's mindsets, attitudes and misconceptions regarding soccer and rugby in a new South African context. There is also little literature available that looks specifically at how Ukhozi FM and Umhlobo FM listeners relate to the broadcast of these popular but diverse codes after the end of apartheid regime. The conclusions drawn up in this study show that radio is still powerful in changing people's behaviour and attitudes not only about different sporting codes aired on radio but also in the effort to promote unity among South Africans regardless of cultural, ethnic racial and genderdifferences. In this regard, radio does cross divides created by issues of colour, culture, gender, age and racial differences. / Thesis (M.A.)-University of Natal, Durban, 2003.
93

IT-system: Försvarsanställdas främsta frustration : Vad kan göras för att öka användarnas uppskattning av IT-systemen? / IT systems: The number one reason for frustration among service members in the Swedish Armed Forces : What can raise the appreciation of the IT systems among the users?

Gillsparr, Torbjörn January 2018 (has links)
Studien tar sin utgångspunkt i att Försvarsmaktens personal återkommande har angett en låg uppskattning till myndighetens IT-system i den årliga medarbetarundersökningen FM VIND. Detta arbete har undersökt bakomliggande orsaker till resultatet genom att studera förhållanden vid de tre taktiska staberna; ATS, MTS och FTS. Med ett antal bakomliggande faktorer identifierade, och med stöd av teoretiska modeller, ges förslag på åtgärder som kan bistå till att IT-systemen får en högre uppskattning hos användarna. Studien redovisar bland annat att FM AP är det mest uppskattade IT-systemet, och att SWECCIS är det minst uppskattade IT-systemet i urvalsgruppen. / The study is based on the fact that the service members of the Swedish Armed Forces have repeatedly stated a low estimate of the IT systems in the annual employee survey FM VIND.  This work has investigated underlying causes of the outcome, by studying the conditions of the three Component Commands; LCC, MCC and ACC. With a number of underlying factors identified, and with the support from theoretical models, suggestions are made for measures that can help the IT systems gain a higher appreciation among users. The study reports, among other things, that FM AP is the most appreciated IT system, and that SWECCIS is the least valued IT system in the selection group.
94

Citometria de fase sólida aplicada ao teste de esterilidade do produto Cloreto de Sódio 0,9% Solução Injetável / Solid-Phase Cytometry applied to sterility test for Sodium chloride 0.9% Injectable Solution Product

Silva, Gisele Badauy Lauria 22 June 2015 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2017-05-05T18:49:22Z No. of bitstreams: 2 Dissertação - Gisele Badauy Lauria Silva - 2015.pdf: 2934917 bytes, checksum: 7660d0a89305d09f8d7a2fe77bda401e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-05-10T13:35:58Z (GMT) No. of bitstreams: 2 Dissertação - Gisele Badauy Lauria Silva - 2015.pdf: 2934917 bytes, checksum: 7660d0a89305d09f8d7a2fe77bda401e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-05-10T13:35:59Z (GMT). No. of bitstreams: 2 Dissertação - Gisele Badauy Lauria Silva - 2015.pdf: 2934917 bytes, checksum: 7660d0a89305d09f8d7a2fe77bda401e (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-06-22 / The sterility test is a test that certificate the absence of viable microorganisms in pharmaceutical raw materials, drugs and medical device. The Solid Phase Cytometry method (SFC) is based on the detection of viable cells through the use of viability markers reagents, that permeate the cell membrane and are cleaved by nonspecific esterase enzymes, forming the fluorochromes that are detected by ChemScan RDI® equipment. It is a fast and innovative method for the sterile injecting drugs area. The objective of the study was to evaluate and validate this technology applied to the sterility test, of the product Sodium Chloride (NaCl) 0.9% Injectable Solution, using the ChemScan RDI® equipment (CS RDI®). Eight microorganisms were evaluated, being six compendial (Clostridium sporogenes NCTC 12935 (ATCC 11437), Pseudomonas aeruginosa NCTC 12924 (ATCC 9027), Staphylococcus aureus NCTC 10788 (ATCC 6538), Bacillus subtilis NCTC 10400 (ATCC 6633), Aspergillus brasiliensis NCPF 2275 (ATCC 16404) and Candida albicans NCPF 3179 (ATCC 10231)) and two "in house” microorganisms, obtained from bioburden monitoring of pre sterilization (Micrococcus luteus and Staphylococcus epidermidis). The Solid Phase Cytometry methodology through logistic regression statistical analysis and Chi-square test, showed to be more rapid than the sterility test by membrane filtration (MF) for all tested microorganisms, reducing the analysis time from 14 days to about 3 hours. The method was validated by the use of qualitative parameters: specificity, limit of detection and robustness. / O teste de esterilidade é um ensaio que certifica a ausência de micro-organismos viáveis em insumos farmacêuticos, medicamentos e produtos para saúde. A Citometria de Fase Sólida (CFS) é um método rápido e inovador para a área de medicamentos estéreis injetáveis e é fundamentado na detecção de células viáveis através da utilização de reagentes marcadores de viabilidade, que permeiam a membrana celular e são clivados por enzimas esterases não específicas, formando o fluorocromo, que são detectados pelo equipamento ChemScan RDI®. O objetivo do estudo foi avaliar e validar esta tecnologia aplicada para o teste de esterilidade, no produto Cloreto de Sódio (NaCl) 0,9% Solução Injetável, utilizando o equipamento ChemScan RDI® (CS RDI®). Os micro-organismos padrões utilizados para os testes foram Clostridium sporogenes NCTC 12935 (ATCC 11437), Pseudomonas aeruginosa NCTC 12924 (ATCC 9027), Staphylococcus aureus NCTC 10788 (ATCC 6538), Bacillus subtilis NCTC 10400 (ATCC 6633), Aspergillus brasiliensis NCPF 2275 (ATCC 16404) e Candida albicans NCPF 3179 (ATCC 10231), e dois micro-organismos “in house” obtidos do monitoramento da biocarga pré esterilização, o Micrococcus luteus e Staphylococcus epidermidis. O método de Citometria de Fase Sólida mostrou-se significativamente mais rápido em relação ao teste de esterilidade por filtração em membrana (FM) para todos os micro-organismos testados, reduzindo o tempo de análise de 14 dias para aproximadamente 3 horas. O método foi validado por meio da utilização dos parâmetros qualitativos: especificidade, limite de detecção e robustez.
95

Metodika zpracování dat pro vizualizaci FM objektů v GIS / Data processing procedure applicable for visualisation of FM objects in GIS environment

Hájek, Filip January 2011 (has links)
This diploma thesis deals with the use of geographic information systems in issue of facility management. Its purpose is to show the advantages of this connection, mostly the visualization and analytical capabilities of GIS. The general issues of facility management are described in the first part of the thesis - what it is about, what it brings, the most important definitions and standards are provided there. Then it continues with theory about connection with GIS and answers the question, why this cooperation is beneficial. It continues with description of importance of GIS during whole life circle of real estate. The chapter is concluded by definition of another powerful tool in FM - CAD/BIM. The fourth chapter discusses one of the important tasks of FM - passportization and its meaning. The last chapter before conclusion focuses on the practical part of thesis dealing with campus of the Czech Post in Malešice. Keywords: Facility management, GIS, passportization, visualization
96

Utveckling och mätning av följdetekteringsalgoritm för V2V med hänsyn till tidsfördröjning / Development and measurement of a followdetection algorithm for V2V with regards to time delay

Rahme, Daniel January 2017 (has links)
Trafikolyckor är ett problem i dagens samhälle och nya lösningar inom intelligenta transportsystem (ITS) efterfrågas. En lösning är fordon-till-fordon kommunikation (V2V), där säkrare trafik kan uppnås genom att fordon sänder relevant trafikdata till omgivande trafik. I denna rapport undersöktes och utvecklades metoder för en följdetekteringsalgoritm inom V2V kommunikation. Uppdraget var att hitta en lösning för följdetektering med GPS och radiokommunikation med FM-RDS, där hänsyn togs till tidsfördröjning. Algoritmer utvecklades i en simuleringsmiljö, för att sedan implementeras i en egenkonstruerad prototyp för mätning i trafik. För effektivt utnyttjande av FM-RDS-paket komprimerades den sända positionen, för att sedan rekonstrueras vid mottagarsidan.Resultaten av simuleringarna och trafikmätningarna visade att det var möjligt att detektera om ett fordon följde efter ett annat i trafiken, med hjälp av GPS-positionering och kommunikation genom FM-RDS med tidsfördröjning av mottagna paket. Vid högre tidsfördröjningar så presterade algoritmen sämre, dock finns det potential till förbättring. Förslag på förbättring av rekonstruktionsfunktionen samt algoritmen behandlas i denna rapport. / Traffic accidents are a problem in today’s society and new solutions regarding intelligent transportation systems (ITS) are being requested. One solution to such is vehicle-to-vehicle communication (V2V), where safer traffic can be achieved by vehicles transmitting relevant traffic information to surrounding vehicles. In this report, we researched and developed methods for a follow-detection algorithm for V2V communication. The task was to find a solution for follow-detection by using GPS and FM-RDS, with regards to time delay. An algorithm was developed in a simulated environment, to then be implemented in a prototype for measuring traffic. For efficient usage of FM-RDS packets, the transmitted position was compressed and then decompressed at the receiving side. The results of the simulations and traffic tests indicated that it was possible to detect if a vehicle followed another in traffic, by using GPS positioning and FM-RDS with time delay. The accuracy of the algorithm degraded at higher time delays, however there is potential for improvements. Suggestions for improvements of the reconstruction function and the algorithm are discussed in this report.
97

Predictive encoding of pure tones and FM-sweeps in the human auditory cortex

Stein, Jasmin, Kriegstein, Katharina von, Tabas, Alejandro 08 April 2024 (has links)
Expectations substantially influence perception, but the neural mechanisms underlying this influence are not fully understood. A prominent view is that sensory neurons encode prediction error with respect to expectations on upcoming sensory input. Although the encoding of prediction error has been previously demonstrated in the human auditory cortex (AC), previous studies often induced expectations using stimulus repetition, potentially confounding prediction error with neural habituation. These studies also measured AC as a single population, failing to consider possible predictive specializations of different AC fields. Moreover, the few studies that considered prediction error to stimuli other than pure tones yielded conflicting results. Here, we used functional magnetic resonance imaging (fMRI) to systematically investigate prediction error to subjective expectations in auditory cortical fields Te1.0, Te1.1, Te1.2, and Te3, and two types of stimuli: pure tones and frequency modulated (FM) sweeps. Our results show that prediction error is elicited with respect to the participants’ expectations independently of stimulus repetition and similarly expressed across auditory fields. Moreover, despite the radically different strategies underlying the decoding of pure tones and FM-sweeps, both stimulus modalities were encoded as prediction error in most fields of AC. Altogether, our results provide unequivocal evidence that predictive coding is the general encoding mechanism in AC.
98

Hydrodynamic Modelling of Water Temperature Distribution in Lake Erken, Sweden

Mazinga, Kondwani January 2024 (has links)
Understanding water temperature dynamics in lakes is essential for ecological and environmental management. This study focuses on Lake Erken, Sweden, aiming to develop and validate a three-dimensional (3D) hydrodynamic model using the MIKE 3 FM modelling system to simulate the lake's water temperature distribution. The model performance was evaluated by comparing simulated water temperature profiles with observed data at various depths, distinguishing between the upper layer and deeper layers. Results showed satisfactory performance, with the model capturing seasonal and spatial variations in the lake’s thermal structure. The root-mean-square error (RMSE) for water temperature simulation ranged between 0.7-1.8°C, and the Nash-Sutcliffe efficiency (NSE) was between 0.86-0.99 across different depths. However, the model has limitations in accurately capturing stratification in deeper layers, especially during the summer months. This research underscores the importance of accurate temperature modelling for understanding lake ecosystems and provides insights for future improvements in hydrodynamic simulations.
99

HOW WELL DOES A BLIND, ADAPTIVE CMA EQUALIZER WORK IN A SIMULATED TELEMETRY MULTIPATH ENVIRONMENT

Law, Eugene 10 1900 (has links)
International Telemetering Conference Proceedings / October 18-21, 2004 / Town & Country Resort, San Diego, California / This paper will present the results of experiments to characterize the performance of a blind, adaptive constant modulus algorithm (CMA) equalizer in simulated telemetry multipath environments. The variables included modulation method, bit rate, received signal-to-noise ratio, delay of the indirect path relative to the direct path, amplitude of the indirect path relative to the direct path, and fade rate. The main measured parameter was bit error probability (BEP). The tests showed that the equalizer usually improved the data quality in the presence of multipath.
100

EXPERIMENTAL RESULTS FOR PCM/FM, TIER 1 SOQPSK, AND TIER II MULTI-H CPM WITH TURBO PRODUCT CODES

Geoghegan, Mark 10 1900 (has links)
International Telemetering Conference Proceedings / October 20-23, 2003 / Riviera Hotel and Convention Center, Las Vegas, Nevada / Improving the spectral-efficiency of aeronautical telemetry has been a principal area of research over the last several years due to the increasing demand for more data and the limitation of available spectrum. These efforts have lead to the development of the ARTM Tier 1 SOQPSK and Tier II Multi-h CPM waveforms which improve the spectral efficiency by two and three times, as compared to legacy PCM/FM, while maintaining similar detection efficiency. Now that more spectrally efficient waveform options are becoming available, another challenge is to further increase the detection performance. Better detection efficiency translates into additional link margin that can be used to extend the operating range, support higher data throughput, or significantly improve the quality of the received data. It is well known that Forward Error Correction (FEC) is one means of achieving this objective at the cost of additional overhead and increased receiver complexity. However, as mentioned above, spectral efficiency is also vitally important meaning that the FEC must also have a low amount of overhead. Unfortunately, low overhead and high coding gain are generally conflicting trades, although recent work has shown that Turbo Product Codes (TPC) are a particularly attractive candidate. Computer simulations predict that very impressive gains in detection performance are possible for a relatively small increase in bandwidth. The main drawbacks are the additional complexity of the decoding circuitry and an increase in receive side latency. This paper presents the latest simulation and hardware performance results of PCM/FM, SOQPSK, and Multi-h CPM with TPC.

Page generated in 0.0416 seconds