The performance of the Mel-Frequency Cepstrum Coefficients (MFCC) may be affected by (1) the number of filters, (2) the shape of filters, (3) the way in which filters are spaced, and (4) the way in which the power spe...The performance of the Mel-Frequency Cepstrum Coefficients (MFCC) may be affected by (1) the number of filters, (2) the shape of filters, (3) the way in which filters are spaced, and (4) the way in which the power spectrum is warped. In this paper, several compar- ison experiments are done to find a best implementation. The traditional MFCC calculation excludes the 0th coefficient for the reason that it is regarded as somewhat unreliable. According to the analysis and experiments, the authors find that it can be regarded as the generalized frequency band energy (FBE) and is hence useful, which results in the FBE-MFCC. The au- thors also propose a better analysis, namely the auto-regressive analysis, on the frame energy, which outperforms its 1st and/or 2nd order differential derivatives. Experiments with the '863' Speech Database show that, compared with the traditional MFCC with its corresponding auto- regressive analysis coefficients, the FBE-MFCC and the frame energy with their corresponding auto-regressive analysis coefficients form the best combination, reducing the Chinese syllable er- ror rate (CSER) by about 10%, while the FBE-MFCC with the corresponding auto-regressive analysis coefficients reduces CSER by 2.5%. Comparison experiments are also done with a quite casual Chinese speech database, named Chinese Annotated Spontaneous Speech (CASS) corpus. The FBE-MFCC can reduce the error rate by about 2.9% on an average.展开更多
The effect of the rare earth（RE） element Y on the microstructure of AZ91 Mg alloy is investigated.A detailed description of the procedure of identifying the intermetallic phases containing Y in the AZ91 Mg alloy wit...The effect of the rare earth（RE） element Y on the microstructure of AZ91 Mg alloy is investigated.A detailed description of the procedure of identifying the intermetallic phases containing Y in the AZ91 Mg alloy with 0.9 wt%Y addition is presented.The results shows that there are two different kinds of RE phases in scanning electron microscopy（SEM） images.Energy dispersive spectrum（EDS） analysis shows that one is rich in Y element and the other is rich in Mn element.According to the element mapping of electron probe microanalysis（EPMA）.the element Al can be found not only in the β-Mg17Al12phase but also in these two RE phases.X-ray diffraction（XRD） and transmission electron microscopy（TEM） results further confirm one of the two RE phases is AI2Y;the phase of Al10Mn2Y has just been determined by transmission electron microscopy（TEM） instead of XRD probably because it is scarce.The shapes of these two RE intermetallic phases are pretty similar.The 3D digital microscopy is employed to observe in-situ the effect of the(5 phase and the above two RE intermetallic phases on the corrosion initiation of the alloys.The results show that the corrosion attack of AZ91 Mg alloy without Y addition starts around the eutectic phase β-Mg17Al12.With the addition of 0.9 wt%Y,the two kinds of Y-rich intermetallic phases act as cathodic effect and a phase in the adjacent of them was activated and cathodic effect of the β-Mg17Al12phase was inhibited.展开更多
Terminal iterative learning control(TILC) is developed to reduce the error between system output and a fixed desired point at the terminal end of operation interval over iterations under strictly identical initial con...Terminal iterative learning control(TILC) is developed to reduce the error between system output and a fixed desired point at the terminal end of operation interval over iterations under strictly identical initial conditions. In this work, the initial states are not required to be identical further but can be varying from iteration to iteration. In addition, the desired terminal point is not fixed any more but is allowed to change run-to-run. Consequently, a new adaptive TILC is proposed with a neural network initial state learning mechanism to achieve the learning objective over iterations. The neural network is used to approximate the effect of iteration-varying initial states on the terminal output and the neural network weights are identified iteratively along the iteration axis.A dead-zone scheme is developed such that both learning and adaptation are performed only if the terminal tracking error is outside a designated error bound. It is shown that the proposed approach is able to track run-varying terminal desired points fast with a specified tracking accuracy beyond the initial state variance.展开更多
Ini Local Government Area (ILGA) is the home of biodiversity, rich in many species of fauna and flora. However, anthropogenic activities carried out by the inhabitants of this area have been a threat to the ecosystem,...Ini Local Government Area (ILGA) is the home of biodiversity, rich in many species of fauna and flora. However, anthropogenic activities carried out by the inhabitants of this area have been a threat to the ecosystem, thereby exterminating the wildlife resources. The data for this study were collected from in-depth interviews with hunters, bushmeat markets, bushmeat sellers, indirect and direct wildlife survey methods, and a semi-structured questionnaire was employed for the household survey. A multiple sampling technique was adopted. A stratified random sampling technique was utilized to stratify the study area into six strata (clans). A proportional sampling technique was used to select 11 villages. In contrast, 60 household heads were randomly selected for questionnaire administration. The study revealed seventeen (17) species of mammal, which accounted for four orders, with Rodentia being the highest (47%). Most species (94%) had the conservation status of Least Concern (LC) based on the IUCN Red List of Threatened Species. Furthermore, illegal hunting and deforestation for agriculture and infrastructural development in the area have led to the loss of wildlife habitats. Thus, a great need for conservation and management practices to protect these vulnerable mammals and their habitats is needed. Hunting laws, afforestation, and reforestation programs should be implemented.展开更多
To mitigate global warming, the call for using clean energy, developing low-carbon economy and ini- tiating green environmental protection has never been louder. One of the hot topics, which has received widespread at...To mitigate global warming, the call for using clean energy, developing low-carbon economy and ini- tiating green environmental protection has never been louder. One of the hot topics, which has received widespread attentions in the world, is the development and utilization of wind energy. At the same time, some of the climate change studies focus on the changes in global wind speeds and strong winds which are related to wind energy utilization. The issues, which are the subjects of these studies, can be summarized in the following.展开更多
文摘The performance of the Mel-Frequency Cepstrum Coefficients (MFCC) may be affected by (1) the number of filters, (2) the shape of filters, (3) the way in which filters are spaced, and (4) the way in which the power spectrum is warped. In this paper, several compar- ison experiments are done to find a best implementation. The traditional MFCC calculation excludes the 0th coefficient for the reason that it is regarded as somewhat unreliable. According to the analysis and experiments, the authors find that it can be regarded as the generalized frequency band energy (FBE) and is hence useful, which results in the FBE-MFCC. The au- thors also propose a better analysis, namely the auto-regressive analysis, on the frame energy, which outperforms its 1st and/or 2nd order differential derivatives. Experiments with the '863' Speech Database show that, compared with the traditional MFCC with its corresponding auto- regressive analysis coefficients, the FBE-MFCC and the frame energy with their corresponding auto-regressive analysis coefficients form the best combination, reducing the Chinese syllable er- ror rate (CSER) by about 10%, while the FBE-MFCC with the corresponding auto-regressive analysis coefficients reduces CSER by 2.5%. Comparison experiments are also done with a quite casual Chinese speech database, named Chinese Annotated Spontaneous Speech (CASS) corpus. The FBE-MFCC can reduce the error rate by about 2.9% on an average.
基金supported by the National Natural Science Foundation of China(No.51101082)the Natural Science Foundation of Inner Mongolia(No.2010BS0801)+1 种基金the Science and Technology Research Project of Colleges and Universities of Inner Mongolia(No.NJ10071)the Open-ends Foundation of State Key Laboratory for Corrosion Protection(No.SKLCP2012KF09)
文摘The effect of the rare earth（RE） element Y on the microstructure of AZ91 Mg alloy is investigated.A detailed description of the procedure of identifying the intermetallic phases containing Y in the AZ91 Mg alloy with 0.9 wt%Y addition is presented.The results shows that there are two different kinds of RE phases in scanning electron microscopy（SEM） images.Energy dispersive spectrum（EDS） analysis shows that one is rich in Y element and the other is rich in Mn element.According to the element mapping of electron probe microanalysis（EPMA）.the element Al can be found not only in the β-Mg17Al12phase but also in these two RE phases.X-ray diffraction（XRD） and transmission electron microscopy（TEM） results further confirm one of the two RE phases is AI2Y;the phase of Al10Mn2Y has just been determined by transmission electron microscopy（TEM） instead of XRD probably because it is scarce.The shapes of these two RE intermetallic phases are pretty similar.The 3D digital microscopy is employed to observe in-situ the effect of the(5 phase and the above two RE intermetallic phases on the corrosion initiation of the alloys.The results show that the corrosion attack of AZ91 Mg alloy without Y addition starts around the eutectic phase β-Mg17Al12.With the addition of 0.9 wt%Y,the two kinds of Y-rich intermetallic phases act as cathodic effect and a phase in the adjacent of them was activated and cathodic effect of the β-Mg17Al12phase was inhibited.
基金supported by National Natural Science Foundation of China(Nos.61374102,61433002 and 61120106009)High Education Science&Technology Fund Planning Project of Shandong Province of China(No.J14LN30)
文摘Terminal iterative learning control(TILC) is developed to reduce the error between system output and a fixed desired point at the terminal end of operation interval over iterations under strictly identical initial conditions. In this work, the initial states are not required to be identical further but can be varying from iteration to iteration. In addition, the desired terminal point is not fixed any more but is allowed to change run-to-run. Consequently, a new adaptive TILC is proposed with a neural network initial state learning mechanism to achieve the learning objective over iterations. The neural network is used to approximate the effect of iteration-varying initial states on the terminal output and the neural network weights are identified iteratively along the iteration axis.A dead-zone scheme is developed such that both learning and adaptation are performed only if the terminal tracking error is outside a designated error bound. It is shown that the proposed approach is able to track run-varying terminal desired points fast with a specified tracking accuracy beyond the initial state variance.
文摘Ini Local Government Area (ILGA) is the home of biodiversity, rich in many species of fauna and flora. However, anthropogenic activities carried out by the inhabitants of this area have been a threat to the ecosystem, thereby exterminating the wildlife resources. The data for this study were collected from in-depth interviews with hunters, bushmeat markets, bushmeat sellers, indirect and direct wildlife survey methods, and a semi-structured questionnaire was employed for the household survey. A multiple sampling technique was adopted. A stratified random sampling technique was utilized to stratify the study area into six strata (clans). A proportional sampling technique was used to select 11 villages. In contrast, 60 household heads were randomly selected for questionnaire administration. The study revealed seventeen (17) species of mammal, which accounted for four orders, with Rodentia being the highest (47%). Most species (94%) had the conservation status of Least Concern (LC) based on the IUCN Red List of Threatened Species. Furthermore, illegal hunting and deforestation for agriculture and infrastructural development in the area have led to the loss of wildlife habitats. Thus, a great need for conservation and management practices to protect these vulnerable mammals and their habitats is needed. Hunting laws, afforestation, and reforestation programs should be implemented.
文摘To mitigate global warming, the call for using clean energy, developing low-carbon economy and ini- tiating green environmental protection has never been louder. One of the hot topics, which has received widespread attentions in the world, is the development and utilization of wind energy. At the same time, some of the climate change studies focus on the changes in global wind speeds and strong winds which are related to wind energy utilization. The issues, which are the subjects of these studies, can be summarized in the following.
