In this work, a novel voice activity detection （VAD） algorithm that uses speech absence probability （SAP） based on Teager energy （TE） was proposed for speech enhancement. The proposed method employs local SAP （...In this work, a novel voice activity detection （VAD） algorithm that uses speech absence probability （SAP） based on Teager energy （TE） was proposed for speech enhancement. The proposed method employs local SAP （LSAP） based on the TE of noisy speech as a feature parameter for voice activity detection （VAD） in each frequency subband, rather than conventional LSAP. Results show that the TE operator can enhance the abiTity to discriminate speech and noise and further suppress noise components. Therefore, TE-based LSAP provides a better representation of LSAP, resulting in improved VAD for estimating noise power in a speech enhancement algorithm. In addition, the presented method utilizes TE-based global SAP （GSAP） derived in each frame as the weighting parameter for modifying the adopted TE operator and improving its performance. The proposed algorithm was evaluated by objective and subjective quality tests under various environments, and was shown to produce better results than the conventional method.展开更多
A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the ...A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current frame.The weight vector of the adaptive filter is updated by the probability of the speech absence.The performance measure of acoustic feedback cancellation is evaluated using normalized misalignment.Experimental results demonstrate that the proposed approach has better performance than the normalized least mean square(NLMS) and the constant step-size affine projection algorithms.展开更多
An improved speech absence probability estimation was proposed using environmental noise classification for speech enhancement.A relevant noise estimation approach,known as the speech presence uncertainty tracking met...An improved speech absence probability estimation was proposed using environmental noise classification for speech enhancement.A relevant noise estimation approach,known as the speech presence uncertainty tracking method,requires seeking the "a priori" probability of speech absence that is derived by applying microphone input signal and the noise signal based on the estimated value of the "a posteriori" signal-to-noise ratio(SNR).To overcome this problem,first,the optimal values in terms of the perceived speech quality of a variety of noise types are derived.Second,the estimated optimal values are assigned according to the determined noise type which is classified by a real-time noise classification algorithm based on the Gaussian mixture model(GMM).The proposed algorithm estimates the speech absence probability using a noise classification algorithm which is based on GMM to apply the optimal parameter of each noise type,unlike the conventional approach which uses a fixed threshold and smoothing parameter.The performance of the proposed method was evaluated by objective tests,such as the perceptual evaluation of speech quality(PESQ) and composite measure.Performance was then evaluated by a subjective test,namely,mean opinion scores(MOS) under various noise environments.The proposed method show better results than existing methods.展开更多
With the rapid global proliferation of the Internet and telecommunication networks, online education, one form of distance education is currently becoming the fastest growing trend of domestic and international educat...With the rapid global proliferation of the Internet and telecommunication networks, online education, one form of distance education is currently becoming the fastest growing trend of domestic and international education. A major challenge to designing online learning is the development of appropriate means to facilitate the social environment that is critical for higher order learning in many disciplines. In many online learning designs, the majority of resources are channeled to web interface design and technology, while little or no resources are devoted to facilitating the teaching and learning process, the negotiation of meaning and the validation of knowledge among peers and instructors that depends on a conducive socio-cultural environment and adequate learner support.展开更多
OBJECTIVE To examine whether17 AAG and STA9090 have anticonvulsant activity in absence epilepsy.METHODS For the acute seizure study,each group of mice received VPA(dissolved in saline) 100 mg·kg-1,17 AAG(dissolve...OBJECTIVE To examine whether17 AAG and STA9090 have anticonvulsant activity in absence epilepsy.METHODS For the acute seizure study,each group of mice received VPA(dissolved in saline) 100 mg·kg-1,17 AAG(dissolved in 50 μL DMSO) 25 mg·kg-1 or STA9090(dissolved in 20 μL DMSO) 50 mg·kg-1 by oral gavage respectively.The control group received DMSO alone.Thirty minutes after oral gavage,PTZ 80 mg·kg-1 was intraperitoneal injected to induce acute seizures.The number of seizures refers to the total number of epileptic mice after PTZ application.Seizure latency was defined by the time elapsed from PTZ injection to the occurrence of the first seizure.The levels of Hsp90β,GLT-1,GFAP and 20 S proteasome β1 in the cortex and hippocampus were detected by Western blotting.RESULTS The mortality were60% for 17 AAG and 43% for STA9090,and the mortality of valproate group dropped to 20%which decreased by 33.3% compared to model group.Seizure latency of valproate group obviously prolonged compared to model group(P<0.05).But the results demonstrated that 17 AAG and STA9090 had no significant differences in seizure latency.The result of Western blotting has shown that inhibition of Hsp90β significantly reduced expressions of both membrane and cytosolic Hsp90β in the hippocampus and cortex of each group of mice.However,the expressions of GLT-1 and GFAP did not show the significant difference in the cortex and hippocampus.The expression of 20 S proteasome β1 had not been obviously changed in the cortex and hippocampus among the groups.CONCLUSION 17 AAG and STA9090 did not have anticonvulsant activity and did not increase the stability of GLT-1 by disrupting proteasome-dependent GLT-1 degradation in PTZ induced mice of absence epilepsy.展开更多
基金Project supported by Inha University Research GrantProject(10031764) supported by the Strategic Technology Development Program of Ministry of Knowledge Economy, Korea
文摘In this work, a novel voice activity detection （VAD） algorithm that uses speech absence probability （SAP） based on Teager energy （TE） was proposed for speech enhancement. The proposed method employs local SAP （LSAP） based on the TE of noisy speech as a feature parameter for voice activity detection （VAD） in each frequency subband, rather than conventional LSAP. Results show that the TE operator can enhance the abiTity to discriminate speech and noise and further suppress noise components. Therefore, TE-based LSAP provides a better representation of LSAP, resulting in improved VAD for estimating noise power in a speech enhancement algorithm. In addition, the presented method utilizes TE-based global SAP （GSAP） derived in each frame as the weighting parameter for modifying the adopted TE operator and improving its performance. The proposed algorithm was evaluated by objective and subjective quality tests under various environments, and was shown to produce better results than the conventional method.
基金Project(2010-0020163)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education
文摘A novel approach is proposed for improving adaptive feedback cancellation using a variable step-size affine projection algorithm(VSS-APA) based on global speech absence probability(GSAP).The variable step-size of the proposed VSS-APA is adjusted according to the GSAP of the current frame.The weight vector of the adaptive filter is updated by the probability of the speech absence.The performance measure of acoustic feedback cancellation is evaluated using normalized misalignment.Experimental results demonstrate that the proposed approach has better performance than the normalized least mean square(NLMS) and the constant step-size affine projection algorithms.
基金Project supported by an Inha University Research GrantProject(10031764) supported by the Strategic Technology Development Program of Ministry of Knowledge Economy,Korea
文摘An improved speech absence probability estimation was proposed using environmental noise classification for speech enhancement.A relevant noise estimation approach,known as the speech presence uncertainty tracking method,requires seeking the "a priori" probability of speech absence that is derived by applying microphone input signal and the noise signal based on the estimated value of the "a posteriori" signal-to-noise ratio(SNR).To overcome this problem,first,the optimal values in terms of the perceived speech quality of a variety of noise types are derived.Second,the estimated optimal values are assigned according to the determined noise type which is classified by a real-time noise classification algorithm based on the Gaussian mixture model(GMM).The proposed algorithm estimates the speech absence probability using a noise classification algorithm which is based on GMM to apply the optimal parameter of each noise type,unlike the conventional approach which uses a fixed threshold and smoothing parameter.The performance of the proposed method was evaluated by objective tests,such as the perceptual evaluation of speech quality(PESQ) and composite measure.Performance was then evaluated by a subjective test,namely,mean opinion scores(MOS) under various noise environments.The proposed method show better results than existing methods.
文摘With the rapid global proliferation of the Internet and telecommunication networks, online education, one form of distance education is currently becoming the fastest growing trend of domestic and international education. A major challenge to designing online learning is the development of appropriate means to facilitate the social environment that is critical for higher order learning in many disciplines. In many online learning designs, the majority of resources are channeled to web interface design and technology, while little or no resources are devoted to facilitating the teaching and learning process, the negotiation of meaning and the validation of knowledge among peers and instructors that depends on a conducive socio-cultural environment and adequate learner support.
基金CAMS Innovation Fund for Medical Sciences(2017-I2M-2-004).
文摘OBJECTIVE To examine whether17 AAG and STA9090 have anticonvulsant activity in absence epilepsy.METHODS For the acute seizure study,each group of mice received VPA(dissolved in saline) 100 mg·kg-1,17 AAG(dissolved in 50 μL DMSO) 25 mg·kg-1 or STA9090(dissolved in 20 μL DMSO) 50 mg·kg-1 by oral gavage respectively.The control group received DMSO alone.Thirty minutes after oral gavage,PTZ 80 mg·kg-1 was intraperitoneal injected to induce acute seizures.The number of seizures refers to the total number of epileptic mice after PTZ application.Seizure latency was defined by the time elapsed from PTZ injection to the occurrence of the first seizure.The levels of Hsp90β,GLT-1,GFAP and 20 S proteasome β1 in the cortex and hippocampus were detected by Western blotting.RESULTS The mortality were60% for 17 AAG and 43% for STA9090,and the mortality of valproate group dropped to 20%which decreased by 33.3% compared to model group.Seizure latency of valproate group obviously prolonged compared to model group(P<0.05).But the results demonstrated that 17 AAG and STA9090 had no significant differences in seizure latency.The result of Western blotting has shown that inhibition of Hsp90β significantly reduced expressions of both membrane and cytosolic Hsp90β in the hippocampus and cortex of each group of mice.However,the expressions of GLT-1 and GFAP did not show the significant difference in the cortex and hippocampus.The expression of 20 S proteasome β1 had not been obviously changed in the cortex and hippocampus among the groups.CONCLUSION 17 AAG and STA9090 did not have anticonvulsant activity and did not increase the stability of GLT-1 by disrupting proteasome-dependent GLT-1 degradation in PTZ induced mice of absence epilepsy.
