VEU - Grup de Tractament de la Parla
http://hdl.handle.net/2117/3746
Sun, 19 Feb 2017 21:10:10 GMT2017-02-19T21:10:10ZPerformance evaluation of interference cancellation techniques using adaptive antennas
http://hdl.handle.net/2117/101104
Performance evaluation of interference cancellation techniques using adaptive antennas
Antón Haro, Carles; Rodríguez Fonollosa, José Adrián; Rodríguez Fonollosa, Javier
Two array-based algorithms, which jointly exploit or compensate for the spatial and temporal characteristics of the propagation channel, are proposed for intercell interference suppression in UMTS scenarios. The first one is the array extension of the Viterbi algorithm and is referred to as Vector Viterbi algorithm (VVA). The second algorithm, known as filtered training sequence multisensor receiver (FTS-MR), belongs to a class of algorithms in which a narrowband beamformer is placed prior to the MLSE detector. In order to assess performance of the proposed schemes, a set of link-level computer simulations adopting FRAMES' proposal for UMTS air-interface as well as realistic channel models for third generation communication systems is provided, Simulation results reveal gains, in terms of C/I, of 7-10 dB for the VVA with respect to the conventional VA and even higher for the FTS-MR.
Wed, 15 Feb 2017 15:05:51 GMThttp://hdl.handle.net/2117/1011042017-02-15T15:05:51ZAntón Haro, CarlesRodríguez Fonollosa, José AdriánRodríguez Fonollosa, JavierTwo array-based algorithms, which jointly exploit or compensate for the spatial and temporal characteristics of the propagation channel, are proposed for intercell interference suppression in UMTS scenarios. The first one is the array extension of the Viterbi algorithm and is referred to as Vector Viterbi algorithm (VVA). The second algorithm, known as filtered training sequence multisensor receiver (FTS-MR), belongs to a class of algorithms in which a narrowband beamformer is placed prior to the MLSE detector. In order to assess performance of the proposed schemes, a set of link-level computer simulations adopting FRAMES' proposal for UMTS air-interface as well as realistic channel models for third generation communication systems is provided, Simulation results reveal gains, in terms of C/I, of 7-10 dB for the VVA with respect to the conventional VA and even higher for the FTS-MR.Assessment of the effect of the financial crisis on agents’ expectations through symbolic regression
http://hdl.handle.net/2117/101084
Assessment of the effect of the financial crisis on agents’ expectations through symbolic regression
Claveria, Oscar; Monte Moreno, Enrique; Torra Porras, Salvador
Agents’ perceptions on the state of the economy can be affected during economic crises.
Tendency surveys are the main source of agents’ expectations. The main objective of this study
is to assess the impact of the 2008 financial crisis on agents’ expectations. With this aim, we
evaluate the capacity of survey-based expectations to anticipate economic growth in the United
States, Japan, Germany and the United Kingdom. We propose a symbolic regression (SR) via
genetic programming approach to derive mathematical functional forms that link survey-based
expectations to GDP growth. By combining the main SR-generated indicators, we generate
estimates of the evolution of GDP. Finally, we analyse the effect of the crisis on the formation
of expectations, and we find an improvement in the capacity of agents’ expectations to anticipate
economic growth after the crisis in all countries except Germany.
Wed, 15 Feb 2017 14:06:00 GMThttp://hdl.handle.net/2117/1010842017-02-15T14:06:00ZClaveria, OscarMonte Moreno, EnriqueTorra Porras, SalvadorAgents’ perceptions on the state of the economy can be affected during economic crises.
Tendency surveys are the main source of agents’ expectations. The main objective of this study
is to assess the impact of the 2008 financial crisis on agents’ expectations. With this aim, we
evaluate the capacity of survey-based expectations to anticipate economic growth in the United
States, Japan, Germany and the United Kingdom. We propose a symbolic regression (SR) via
genetic programming approach to derive mathematical functional forms that link survey-based
expectations to GDP growth. By combining the main SR-generated indicators, we generate
estimates of the evolution of GDP. Finally, we analyse the effect of the crisis on the formation
of expectations, and we find an improvement in the capacity of agents’ expectations to anticipate
economic growth after the crisis in all countries except Germany.A segmentation algorithm based on acoustical features using a self organizing neural network.
http://hdl.handle.net/2117/100998
A segmentation algorithm based on acoustical features using a self organizing neural network.
Monte Moreno, Enrique
In this paper we investigate the use of a self-organizing map in an acoustic segmentation task. The aim is to obtain a limited number of acoustic classes and to segment whenever a change in the class between two adjacent frames occurs. Energy in different frequency ranges is used as input in the map training process. A structure based on a Kohonen map connected to a neural network trained with the back-propagation algorithm is proposed.
Tue, 14 Feb 2017 15:02:20 GMThttp://hdl.handle.net/2117/1009982017-02-14T15:02:20ZMonte Moreno, EnriqueIn this paper we investigate the use of a self-organizing map in an acoustic segmentation task. The aim is to obtain a limited number of acoustic classes and to segment whenever a change in the class between two adjacent frames occurs. Energy in different frequency ranges is used as input in the map training process. A structure based on a Kohonen map connected to a neural network trained with the back-propagation algorithm is proposed.Vocoder Design based on HOS
http://hdl.handle.net/2117/100996
Vocoder Design based on HOS
Moreno Bilbao, M. Asunción; Rodríguez Fonollosa, José Adrián; Vidal Manzano, José
This paper deals with the application of Higher Order Statistics (HOS) in speech coding. A new model for speech production is implemented and the parameters of the vocal track are obtained from a linear combination of third order cumulants of the speech signal. Noisy signals have been used to test the system including colored Gaussian noise and sinusoidal interfering signals. Pitch and voicing decision are also obtained by HOS analysis of speech.
Tue, 14 Feb 2017 14:55:01 GMThttp://hdl.handle.net/2117/1009962017-02-14T14:55:01ZMoreno Bilbao, M. AsunciónRodríguez Fonollosa, José AdriánVidal Manzano, JoséThis paper deals with the application of Higher Order Statistics (HOS) in speech coding. A new model for speech production is implemented and the parameters of the vocal track are obtained from a linear combination of third order cumulants of the speech signal. Noisy signals have been used to test the system including colored Gaussian noise and sinusoidal interfering signals. Pitch and voicing decision are also obtained by HOS analysis of speech.Albayzin speech database: design of the phonetic corpus
http://hdl.handle.net/2117/100991
Albayzin speech database: design of the phonetic corpus
Moreno Bilbao, M. Asunción; Poig, D; Bonafonte Cávez, Antonio; Lleida, E; Llisterri, J; Mariño Acebal, José Bernardo; Nadeu Camprubí, Climent
This paper describes the phonetic content of Albayzin, a spoken database for Spanish designed for speech recognition purposes. A statistical study of a large sample of spontaneous speech is presented, and the phonetic and statistical criteria for the final constitution of the database are discussed. Finally, the contents of the phonetic database are analyzed
Tue, 14 Feb 2017 14:03:36 GMThttp://hdl.handle.net/2117/1009912017-02-14T14:03:36ZMoreno Bilbao, M. AsunciónPoig, DBonafonte Cávez, AntonioLleida, ELlisterri, JMariño Acebal, José BernardoNadeu Camprubí, ClimentThis paper describes the phonetic content of Albayzin, a spoken database for Spanish designed for speech recognition purposes. A statistical study of a large sample of spontaneous speech is presented, and the phonetic and statistical criteria for the final constitution of the database are discussed. Finally, the contents of the phonetic database are analyzedMultiple multilabelling applied to hmm-based noisy speech recognition
http://hdl.handle.net/2117/100931
Multiple multilabelling applied to hmm-based noisy speech recognition
Hernando Pericás, Francisco Javier; Mariño Acebal, José Bernardo; Moreno Bilbao, M. Asunción; Nadeu Camprubí, Climent
Mon, 13 Feb 2017 14:43:24 GMThttp://hdl.handle.net/2117/1009312017-02-13T14:43:24ZHernando Pericás, Francisco JavierMariño Acebal, José BernardoMoreno Bilbao, M. AsunciónNadeu Camprubí, ClimentAn efficient algorithm to find the best state sequence in hsmm
http://hdl.handle.net/2117/100929
An efficient algorithm to find the best state sequence in hsmm
Bonafonte Cávez, Antonio; Mariño Acebal, José Bernardo
Hidden Markov Modeling (HMM) techniques have been applied successfully to speech analysis. However, it has been claimed [1-7] that a major weakness of HMM is that the state duration probability density functions (SDPDF) are exponential, which is not appropriate for modelling speech events. In order to cope with this deficiency some authors have proposed to model explicitly the state duration. In these models the first order Markov hypothesis is broken in the loop transitions. Thus, the new models have been called Hidden Semi-Markov Models (HSMM). Different solutions have been proposed being the main common drawback the increase of the computational time by a factor D, being D the maximum time allowed in each state. In this paper a modified Viterbi algorithm which finds the best state sequence of HSMM is proposed. The proposed algorithm deals with log-convex parametric SDPDF. The log-convex property is fulfilled by the parametric functions usually applied. This method increases the computational burden with respect to conventional HMM by an empirical factor of just 3.2 without losing optimality and without increasing the storage with respect to other approaches. A more efficient algorithm is presented for the case that the duration of the states is modeled by bounded functions.
Mon, 13 Feb 2017 14:39:28 GMThttp://hdl.handle.net/2117/1009292017-02-13T14:39:28ZBonafonte Cávez, AntonioMariño Acebal, José BernardoHidden Markov Modeling (HMM) techniques have been applied successfully to speech analysis. However, it has been claimed [1-7] that a major weakness of HMM is that the state duration probability density functions (SDPDF) are exponential, which is not appropriate for modelling speech events. In order to cope with this deficiency some authors have proposed to model explicitly the state duration. In these models the first order Markov hypothesis is broken in the loop transitions. Thus, the new models have been called Hidden Semi-Markov Models (HSMM). Different solutions have been proposed being the main common drawback the increase of the computational time by a factor D, being D the maximum time allowed in each state. In this paper a modified Viterbi algorithm which finds the best state sequence of HSMM is proposed. The proposed algorithm deals with log-convex parametric SDPDF. The log-convex property is fulfilled by the parametric functions usually applied. This method increases the computational burden with respect to conventional HMM by an empirical factor of just 3.2 without losing optimality and without increasing the storage with respect to other approaches. A more efficient algorithm is presented for the case that the duration of the states is modeled by bounded functions.Pitch determination of noisy speech using higher order statistics
http://hdl.handle.net/2117/100789
Pitch determination of noisy speech using higher order statistics
Moreno Bilbao, M. Asunción; Rodríguez Fonollosa, José Adrián
The use of third-order statistics to determine the pitch of a speech signal and how they can eliminate the effect of a wide range of noises, including those generated by periodic sources, are shown. The proposed algorithm is based on the property that higher-order statistics can extract useful information about the statistics of voiced frames, and they can separate speech from noise. Third-order statistics are quite insensitive to most noises (Gaussian, sinusoidal, car noise, etc.) because these noises have a symmetric probability density function, and therefore their third-order cumulants are zero. The algorithm has been tested in noise-corrupted speech, at different levels of signal to noise ratio, and with different kinds of noise. The results show that this new algorithm gives in all the cases a much better estimation of the pitch than the conventional autocorrelation method.
Thu, 09 Feb 2017 17:23:02 GMThttp://hdl.handle.net/2117/1007892017-02-09T17:23:02ZMoreno Bilbao, M. AsunciónRodríguez Fonollosa, José AdriánThe use of third-order statistics to determine the pitch of a speech signal and how they can eliminate the effect of a wide range of noises, including those generated by periodic sources, are shown. The proposed algorithm is based on the property that higher-order statistics can extract useful information about the statistics of voiced frames, and they can separate speech from noise. Third-order statistics are quite insensitive to most noises (Gaussian, sinusoidal, car noise, etc.) because these noises have a symmetric probability density function, and therefore their third-order cumulants are zero. The algorithm has been tested in noise-corrupted speech, at different levels of signal to noise ratio, and with different kinds of noise. The results show that this new algorithm gives in all the cases a much better estimation of the pitch than the conventional autocorrelation method.Analytic performance evaluation of cumulant-based fir system identification methods
http://hdl.handle.net/2117/100715
Analytic performance evaluation of cumulant-based fir system identification methods
Rodríguez Fonollosa, José Adrián; Mendel, J M
The covariances of the third- and fourth-order sample cumulants of stationary processes are derived. The resulting expressions are used to obtain the analytical performance of such methods as a function of the coefficients and statistics of the input sequence. The lower bound in the variance is compared for different sets of sample statistics to provide insight about the information carried by each sample statistic. The effect of the presence of noise on the accuracy of the estimates is studied analytically. The results are illustrated graphically with plots of the variance of the estimates as a function of the parameters or the signal-to-noise ratio. Monte Carlo simulations are included for comparison with the predicted analytical performance.
Wed, 08 Feb 2017 16:47:33 GMThttp://hdl.handle.net/2117/1007152017-02-08T16:47:33ZRodríguez Fonollosa, José AdriánMendel, J MThe covariances of the third- and fourth-order sample cumulants of stationary processes are derived. The resulting expressions are used to obtain the analytical performance of such methods as a function of the coefficients and statistics of the input sequence. The lower bound in the variance is compared for different sets of sample statistics to provide insight about the information carried by each sample statistic. The effect of the presence of noise on the accuracy of the estimates is studied analytically. The results are illustrated graphically with plots of the variance of the estimates as a function of the parameters or the signal-to-noise ratio. Monte Carlo simulations are included for comparison with the predicted analytical performance.Tecnicas de modelado AR robusto de la señal de voz para reconocimiento del habla en ambientes ruidosos
http://hdl.handle.net/2117/100714
Tecnicas de modelado AR robusto de la señal de voz para reconocimiento del habla en ambientes ruidosos
Hernando Pericás, Francisco Javier; Riu, D.; Nadeu Camprubí, Climent
Wed, 08 Feb 2017 16:29:44 GMThttp://hdl.handle.net/2117/1007142017-02-08T16:29:44ZHernando Pericás, Francisco JavierRiu, D.Nadeu Camprubí, Climent