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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.
21

A Design of Mandarin Speech Recognition System for Addresses in Taiwan

Cheng, Chi-Feng 31 August 2005 (has links)
A Mandarin speech recognition system for addresses in Taiwan, based on end-point detection, MFCC and HMM, is proposed and implemented in this thesis. It includes both phrase and monosyllable recognition tasks. For the phrase recognition part, we select the initial candidates before the final recognition stage to tremendously reduce the computational time. On the other side, for the monosyllable recognition part, we further refine the recognition details to improve the correct rate under easily confused circumstances. The final system can achieve 85% correct identification rate, and the address recognition can be completed within 2 seconds in the laboratory environment for speaker-dependent case.
22

A System Design of Chinese Resume by Speech Construction

Chen, Yue-sheng 28 August 2006 (has links)
A system of Chinese resume by speech construction is developed by the use of a novel segmentation mechanism and the classical Hidden Markov Model. The recognition system is based on both mono-syllable HMM's and speech-text alignment schemes. Experimental results indicate that the amount of training materials used for feature extraction can be greatly reduced, and the text content of the recorded speech training data can be different from those of the recognition tasks as well. Each phrase in the resume can be identified within one second, that is approximately the same as the graduate did last year. Furthermore, the user interface of the resume system has been redesigned and polished by the GTK toolkit in order to enable event-driven X-window operations.
23

A Design of Speech Recognition System for Chinese Names of Historical Figures Around the World

Lin, Wei-Ci 07 September 2006 (has links)
A design of speech recognition system for Chinese names of historical figures around the world is proposed in this thesis. A speech database of approximately forty-six thousand Chinese names is collected and recorded twice for system evaluation. This system applies Mel-frequency cepstrum coefficients, monosyllable HMM¡¦s and speech-text alignment scheme to accomplish initial candidate selection. A Mandarin pitch identification mechanism is then followed to increase the correct rate and obtain the final answer. The experimental results indicate that a 90% correct identification rate can be achieved, under the condition that the first session recording material is used for training and the second one for testing. For the speaker dependent case, the correct name can be recognized within 1.5 seconds, using a PC with an Intel Celeron 2.4 GHz CPU and RedHat Linux 9.0 Operation System.
24

A Design of Recognition Rate Improving Strategy for Mandarin Speech Recognition System - A Case Study on Address Inputting System and Phrase Recognition System

Hsieh, Wen-kuang 24 August 2009 (has links)
This thesis investigates the recognition rate improvement strategies for a Mandarin speech recognition system. Both automatic tone recognition and consonant correction schemes are studied and applied to the Mandarin address inputting system and the Mandarin 2, 3, 4-word phrase recognition systems. For automatic tone recognition scheme, the acoustic properties of the four tones in the Mandarin training database are estimated statistically by 4 sets of parameters within 6 minutes. These automatically generated parameters can greatly increase the tone recognition accuracy, and at the same time reduce the amount of time spent in the manual tone parameter adjustment, that is about 8 hours in general. For consonant correction scheme, the sub-syllable models are developed to enhance the consonant recognition accuracy, and hence further improve the overall correct rate for the whole Mandarin phrases. Experimental results indicate that over 90% correct rate can be achieved for the Mandarin address inputting system with 180 thousand place names by applying the above two schemes. Furthermore, the recognition rates for the Mandarin 2, 3, 4-word phrase recognition systems with 116 thousand phrases in total can be improved from 77%, 94% and 97.5%, to 85%, 96% and 98% respectively.
25

Bioquímica quântica das estatinas, aspirina e anti-hipertensivos

Costa, Roner Ferreira da January 2011 (has links)
COSTA, Roner Ferreira da. Bioquímica quântica das estatinas, aspirina e anti-hipertensivos. 2011. 185 f. Tese (Doutorado em Física) - Programa de Pós-Graduação em Física, Departamento de Física, Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2011. / Submitted by Edvander Pires (edvanderpires@gmail.com) on 2015-05-29T22:17:20Z No. of bitstreams: 1 2011_tese_rfcosta.pdf: 5384677 bytes, checksum: b7096c8a3fe046f09eec5640166b7cba (MD5) / Approved for entry into archive by Edvander Pires(edvanderpires@gmail.com) on 2015-05-29T22:18:27Z (GMT) No. of bitstreams: 1 2011_tese_rfcosta.pdf: 5384677 bytes, checksum: b7096c8a3fe046f09eec5640166b7cba (MD5) / Made available in DSpace on 2015-05-29T22:18:27Z (GMT). No. of bitstreams: 1 2011_tese_rfcosta.pdf: 5384677 bytes, checksum: b7096c8a3fe046f09eec5640166b7cba (MD5) Previous issue date: 2011 / As doenças cardiovasculares (CVDs) compreendem um amplo espectro de doenças do coração e vasos sanguíneos (artérias e veias), entre as quais se incluem a doença das artérias coronárias, o ataque cardíaco, a angina, a síndrome coronariana aguda, o aneurisma da aorta, arritmias cardíacas, a doença cardíaca congênita, a insuficiência cardíaca e a doença cardíaca reumática. Entre os principias fármacos que tratam as doenças cardiovasculares estão: (i) as estatinas, que atuam inibindo a 3-hidroxi-3-metilgluratil coenzima A (HMG-CoA) redutase no processo de conversão da HMG-CoA em mevalonato, numa das etapas da biossíntese do colesterol. Observa-se em ensaios clínicos que a ação das estatinas pode diminuir os níveis de colesterol de baixa densidade (LDL) entre 20\% e 60\%, reduzindo os eventos coronarianos em até 1/3 no período de cinco anos; (ii) a aspirina, com a qual há mais de 400 preparações nos EUA e se produz cerca de 20 mil toneladas anualmente. Após mais de um século de prática clínica, a aspirina continua sendo a droga antitrombótica, antitérmica, analgésica e antiproliferativa mais amplamente recomendada. Ela age bloqueando a biossíntese de hormônios inflamatórios prostanóides através da inibição das enzimas ciclooxigenase COX-1 e COX-2; (iii) os anti-hipertensivos, para os quais a Enzima Conversora de Angiotensina (ECA) é o principal alvo (inibidores da ECA estão no mercado a mais de 20 anos) visando o combate das pressões arteriais elevadas, que provocam alterações nos vasos sanguíneos e na musculatura do coração, e levam a hipertrofia do ventrículo esquerdo do coração, acidente vascular cerebral, infarto do miocárdio, morte súbita, insuficiências renal e cardíaca, etc. A hipertensão arterial (HTA) ou hipertensão arterial sistêmica (HAS), conhecida popularmente como pressão alta, é uma das doenças com maior prevalência no mundo moderno. A ECA atua na regulação da pressão sanguínea via conversão do decapeptídeo angiotensina I no potente vasopressor angiotensina II e também pela inativação da bradicinina, sendo componente central do Sistema Renina-Angiotensina-Aldeosterona (SRAA), que controla a pressão sanguínea e tem forte influência nas funções relacionadas ao coração e os rins, bem como na contração dos vasos sanguíneos. Nesta tese realiza-se um estudo da bioquímica quântica de estatinas (atorvastina, rosuvastatina, cerivastatina, mevastatina, sinvastatina e fluvastatina), da aspirina/bromoaspirina e de anti-hipertensivos (captopril, enalapril, lisinopril, ramipril, trandolapril e perindopril) levando-se em conta dados cristalográficos dos seus sítios de ligação nas proteínas HMGR, COX-1 (o da aspirina foi simulado partindo-se dos dados da bromoaspirina) e ECA, respectivamente. As simulações computacionais foram realizadas considerando-se a Teoria do Funcional de Densidade (DFT) na aproximação da densidade local (LDA) e funcional de troca e correlação PWC, com energia de interação entre os resíduos das proteínas circunscritos ao sítio de ligação de raio r e os fármacos calculada através do método de fracionamento molecular com capas conjugadas (MFCC). Os resultados obtidos para as estatinas sugerem que: (i) as mais (menos) eficazes são a atorvastatina e a rosuvastatina (sinvastatina e fluvastatina), o que está de acordo com a clínica e valores dos seus índices de concentrações inibitórias IC50; (ii) sítios de ligação com raios de pelo menos 12 Å (além do raio de 9,5 Å sugerido pela análise estrita de dados cristalográficos) devem ser considerados para que resíduos importantes como E665, D767, e R702 sejam considerados para que as eficiências das estatinas sejam corretamente explicadas. Para a aspirina/bromoaspirina utilizou-se um refinamento quântico de segunda ordem dos dados cristalográficos para se demonstrar que a energia de ligação de ambos com a COX-1 são aproximadamente a mesma, o que explica resultados experimentais de IC50 similares. A existência de resíduos atrativos e resulsivos é destacada, mostrando-se que Arg120 é o resíduo que mais atrai o ácido salicílico após acetilação da Ser530, seguido de Ala527, Leu531, Leu359 e Ser353; por outro lado, Glu524 é o resíduo repulsivo mais efetivo (intensidade comparável ao Arg120), nunca tendo sido antes considerado como resíduo importante no sítio de ligação da aspirina/bromoaspirina na COX-1. Finalmente, no caso dos anti-hipertensivos, obtém-se que é necessário se considerar raios do sítio de ligação de 16 Å para se obter que o lisinopropil e o ramipril (trandolapril e perindopril) apresentam as maiores (menores) energias de ligação, o que explica a maior (menor) constante de inibição dos mesmos entre os anti-hipertensivos estudados para a ACE da Drosophila melanogaster.
26

Bioqu?mica qu?ntica na diferencia??o dos n?veis de ativa??o de receptores AMPA por agonistas parciais Wilardina

Lima Neto, Jos? Xavier de 26 February 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-22T23:19:51Z No. of bitstreams: 1 JoseXavierDeLimaNeto_DISSERT.pdf: 20857554 bytes, checksum: 04aea5694e5da65425668c7f81185381 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-26T00:31:29Z (GMT) No. of bitstreams: 1 JoseXavierDeLimaNeto_DISSERT.pdf: 20857554 bytes, checksum: 04aea5694e5da65425668c7f81185381 (MD5) / Made available in DSpace on 2016-02-26T00:31:29Z (GMT). No. of bitstreams: 1 JoseXavierDeLimaNeto_DISSERT.pdf: 20857554 bytes, checksum: 04aea5694e5da65425668c7f81185381 (MD5) Previous issue date: 2015-02-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / No sistema nervoso central de mam?feros, a transmiss?o sin?ptica r?pida entre c?lulas nervosa ? realizada primariamente pelo receptor ?-amino-3-hidroxi-5-metil-4- isoxazolpropi?nico (AMPA), um Receptor Ionotr?pico de Glutamato, que est? relacionado com a aprendizagem, mem?ria e homeostase do sistema nervoso. Defici?ncias em seu funcionamento s?o correlacionadas com o desenvolvimento de muitas desordens cerebrais, tais como epilepsia, esquizofrenia, autismo, Parkinson e Alzheimer. O uso dos an?logos de wilardina tem se mostrado uma poderosa ferramenta para o entendimento dos mecanismos de ativa??o e dessensibiliza??o deste receptor, pois a modifica??o em um ?nico ?tomo deste ligante permite a observa??o de variados n?veis de efic?cia. Neste trabalho, tirando vantagem das estruturas de Fl?or Wilardina (1.35?), Hidrog?nio Wilardina (1.65?), Bromo Wilardina (1.8?) e Iodo Wilardina (2.15?), co-cristalizadas com o receptor GluA2 com os c?digos 1MQI, 1MQJ, 1MQH e 1MQG, respectivamente, buscou-se diferenciar energeticamente a efic?cia dos quatro ligantes. Os complexos foram submetidos a c?lculos energ?ticos baseados na teoria do funcional da densidade (DFT), sob a ?ptica do m?todo do fracionamento molecular com caps conjugados (MFCC). Os resultados obtidos mostram uma rela??o entre os valores energ?ticos e a ordem de efic?cia de cada wilardina (FW > HW > BrW > IW), ainda evidenciam a import?ncia de E705, R485, Y450, S654, T655, T480 e P478 como os amino?cidos que contribuem mais fortemente com a intera??o dos quatro agonistas parciais wilardina. Juntamente com isto, delineamos o comportamento de M708, sendo atra?do pelos ligantes FW e HW, e repelido por BrW e IW. Com os dados relatados neste trabalho, faz-se poss?vel um melhor entendimento do receptor AMPA, o que pode servir como auxilio no desenvolvimento de novos f?rmacos para este sistema. / In the central nervous system (CNS) of mammalian, fast synaptic transmission between nerve cells is performed primarily by ?-amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid (AMPA) receptors, an ionotropic glutamate receptor that is related with learning, memory and homeostasis of the nervous system. Impairments in their functions are correlated with development of many brain desorders, such as epilepsy, schizophrenia, autism, Parkinson and Alzheimer. The use of willardiine analogs has been shown a powerful tool to understanding of activation and desensitization mechanisms of this receptors, because the modification of a single ligand atom allows the observation of varying levels of efficacy. In this work, taking advantage of Fluorine Willardiine (1.35?), Hydrogen Willardiine (1.65?), Bromine Willardiine (1.8?) and Iodine Willardiine (2.15?) structures co-crystalized with GluA2 with codes 1MQI, 1MQJ, 1MQH and 1MQG, we attempted to energetically differentiate the four ligands efficacy. The complexes were submitted to energetic calculations based on density functional theory (DFT), under the optics of molecular fractionation with conjugate caps (MFCC) method. Obtained results show a relationship between the energetic values and willardiines efficacy order (FW> HW > BrW > IW), also show the importance of E705, R485, Y450, S654, T655, T480 e P478 as the amino acids that contribute most strongly with the interaction of four partial agonists. Furthermore, we outlined the M708 behaviour, attracted by FW and HW ligands, and repels by BrW and IW. With the datas reported on this work, it is possible for a better understanding of the AMPA receptor, which can serve as an aid in the development of new drugs for this system.
27

Bioqu?mica qu?ntica da capreomicina e da estreptomicina em complexo com o ribossomo bacteriano

Vianna, J?ssica de F?tima 16 February 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-03T22:31:54Z No. of bitstreams: 1 JessicaDeFatimaVianna_DISSERT.pdf: 3724208 bytes, checksum: f7d62fbcd54bf6b212f2003b461810c5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-11T18:14:29Z (GMT) No. of bitstreams: 1 JessicaDeFatimaVianna_DISSERT.pdf: 3724208 bytes, checksum: f7d62fbcd54bf6b212f2003b461810c5 (MD5) / Made available in DSpace on 2017-04-11T18:14:29Z (GMT). No. of bitstreams: 1 JessicaDeFatimaVianna_DISSERT.pdf: 3724208 bytes, checksum: f7d62fbcd54bf6b212f2003b461810c5 (MD5) Previous issue date: 2017-02-16 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / A tuberculose ? uma doen?a bacteriana provocada pelo Mycobacterium tuberculosis, e de acordo com a Organiza??o Mundial de Sa?de, apenas em 2015 foram 10,4 milh?es de novos casos relatados e 1,4 milh?o de mortes. Cresce o n?mero de casos de pacientes infectados com cepas resistentes aos antimicrobianos mais comumente utilizados, fazendo-se necess?rio uso de drogas de segunda-linha. A capreomicina e a estreptomicina encaixam-se nesse grupo, e s?o antibi?ticos que possuem como mecanismo de atua??o a inibi??o da s?ntese proteica. Entretanto, seus mecanismos de liga??o em seus s?tios s?o distintos: a capreomicina ? capaz de se ligar a ambas subunidades ribossomais (30S e 50S), enquanto que a estreptomicina liga-se ? subunidade ribossomal menor (30S), e interage com alguns pontos da prote?na S12. Atrav?s de dados cristalogr?ficos e simula??es computacionais, foi calculada a energia de intera??o da capreomicina e da estreptomicina com cada um dos res?duos constituintes de seus s?tios utilizando a Teoria Funcional da Densidade (DFT) e do M?todo de Fracionamento Molecular com Capas Conjugadas (MFCC). Os resultados revelaram valores energ?ticos de cada nucleot?deo pertencente ao s?tio de liga??o desses dois medicamentos, como tamb?m dos amino?cidos da prote?na S12 com os quais a estreptomicina interage. Assim, para a capreomicina na subunidade 30S, foram avaliados res?duos presentes em um raio de at? 14 ? distantes do f?rmaco, totalizando 44 res?duos; e na subunidade 50S, 30 nucleot?deos foram analisados, e estavam distribu?dos at? o raio de 30 ? de dist?ncia. Com a estreptomicina foram levados em considera??o 60 nucleot?deos distribu?dos at? 12,5 ? de dist?ncia da droga na subunidade 30S, e 25 amino?cidos da prote?na S12 com at? 15 ? de dist?ncia. Identificamos tamb?m as contribui??es das liga??es de hidrog?nio e das intera??es hidrof?bicas nas intera??es f?rmaco-receptor; as regi?es dos f?rmacos que mais contribu?ram para as fixa??es desses em seus s?tios de liga??o; como tamb?m a identifica??o dos res?duos que s?o mais associados ?s muta??es e consequente resist?ncia. / Tuberculosis is a disease caused by Mycobacterium tuberculosis, and according to the World Health Organization, only in 2015 occurred 10.4 million new cases reported and 1.4 million deaths. The number of cases of patients infected with antimicrobial resistant strains most used is increasing, requiring the use of second-line drugs. Capreomycin and streptomycin are part of the group, and are antibiotics whose mechanism of action is the inhibition of protein synthesis. However, its binding mechanisms in their sites are distinct: capreomycin is able to bind to both ribosomal (30S and 50S) subunits, whereas streptomycin binds to the smaller ribosomal subunit (30S), and interacts with some points of S12 protein. Through crystallographic data and computational simulations, we calculated the interaction energy of capreomycin and streptomycin with each of the residues component of their sites using the Density Functional Theory (DFT) and Molecular Fractionation with Conjugated Caps (MFCC). The results showed energy values of each nucleotide belonging to binding site of these two drugs, as well as the amino acids of the S12 protein with which streptomycin interacts. Thus, for capreomycin in the 30S subunit, residues present in a radius of up to 14 ? distant from the drug, totaling 44 residues; and in the 50S subunit, 30 nucleotides were analyzed, and were distributed up to the 30? radius distance. Regarding streptomycin, 60 nucleotides distributed up to 12.5 ? away from the drug in the 30S subunit, and 25 amino acids of the S12 protein with up to 15 ? were taken into account. We also identify the contributions of hydrogen bonds and hydrophobic interactions in drug-receptor interactions; the regions of the drugs that most contributed to the anchorages of these in their binding sites; as well as the identification of residues that are most associated with mutations and consequent resistance.
28

Text-Dependent Speaker Verification Implemented in Matlab Using MFCC and DTW

Tolunay, Atahan January 2010 (has links)
Even though speaker verification is a broad subject, the commercial and personal use implementations are rare. There are several problems that need to be solved before speaker verification can become more useful. The amount of pattern matching and feature extraction techniques is large and the decision on which ones to use is debatable. One of the main problems of speaker verification in general is the impact of noise. The very popular feature extraction technique MFCC is inherently sensitive to mismatch between training and verification conditions. MFCC is used in many speech recognition applications and is not only useful in text-dependent speaker verification. However the most reliable verification techniques are text-dependent. One of the most popular pattern matching techniques in text-dependent speaker verification is DTW. Although having limitations outside the text-dependent applications it is a reliable way of matching templates even with limited amount of training material. The signal processing techniques, MFCC and DTW are explained and discussed in detail along with a Matlab program where these techniques have been implemented. The choices made in signal processing, feature extraction and pattern matching  are determined by discussions of available studies on these topics. The results indicate that it is possible to program text-dependent speaker verification systems that are functional in clean conditions with tools like Matlab.
29

Odhad formantových kmitočtů pomocí strojového učení / Estimation of formant frequencies using machine learning

Káčerová, Erika January 2019 (has links)
This Master's thesis deals with the issue of formant extraction. A system of scripts in Matlab interface is created to generate values of the first three formant frequencies from speech recordings with the use of Praat and Snack(WaveSurfer). Mel Frequency Cepstral Coefficients and Linear Predictive Coefficients are extracted from the audio files in order to be added to the database. This database is then used to train a neural network. Finally, the designed neural network is tested.
30

Dekodér pro systém detekce klíčových slov / Decoder for key word detection system

Krotký, Jan January 2009 (has links)
The essay presents the basic characteristics of human speech recognition, describes systems for the detection of key words and further deals with the proposal of each decoder blocks divided into three chapters. The first one describes the operations that are performed before the signal distribution of the framework and the segmentation. The second chapter describes the calculation of short-term energy, the number of zero passes and self-correlative, prediction and Mel-frequency cepstral coefficients. The third chapter, which describes the design of the block decoder, describes the method of dynamic time destruction and the method based on hidden Markov model. The final part of the essay describes decoders working with a speech and a proposal for a simple decoder working with isolated words, which was based issued and tested based on the preceding chapters.

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