检索结果-南通市图书馆

Automatic context induction for tone model integration in mandarin speech recognition

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2012年第1期19卷 94-100页

作者： huANG hao LI Bing-hu Department of Information Science and Engineering Xinjiang University Urumqi 830046 China Laboratory of Multi-Lingual Information Technology Xinjiang University Urumqi 830046 China

Tone model （TM） integration is an important task for mandarin speech recognition. It has been proved to be effective to use discriminatively trained scaling factors when integrating TM scores into multi-pass speech recognition. Moreover, context-dependent （CD） scaling can be applied for better interpolation between the models. One limitation of this approach is a large number of parameters will be introduced, which makes the technique prone to overtraining. In this paper, we propose to induce context-dependent model weights by using automatically derived phonetic decision trees. Question at each tree node is chosen to minimize the expected recognition error on the training data. First order approximation of the minimum phone error （MPE） objective function is used for question pruning to make tree building efficient. Experimental results on continuous mandarin speech recognition show the method is capable of inducing the most crucial phonetic contexts and obtains significant error reduction with far fewer parameters, compared with that obtained by using manually designed context-dependent scaling parameters.

关键词： TM integration MPE decision tree mandarin speech recognition context-dependent

Liquid Crystalline Polymers

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2022年第2期40卷 121-123页

作者： Zhi-hao Shen qi-Feng Zhou Peking University

History of Liquid Crystalline PolymersThe liquid crystalline(LC)state was first observed by Austrian botanist and chemist *** more than a century ago,and it was then confirmed in 1888 by German physicist *** who named such a state of matter as"liquid crystal"in *** low molecular mass(LMM)liquid crystals were successfully used in LC displays(LCDs),the development of LC polymers(LCPs)followed an independent ***,LCPs are prepared with the incorporation of mesogenic groups that are responsible for the formation of LC mesophases,such as rod-like(calamitic)and discotic ones,into polymer *** on where the mesogens are attached,traditionally there are three major categories of ***-chain LCPs(MCLCPs)have mesogens in the polymer backbone,while mesogens of side-chain LCPs(SCLCPs)are incorporated as side groups in a polymer with a relatively flexible main *** main-chain/side-chain combined LCPs(MCSCLCPs),mesogens are in both the backbone and side *** classes of LCPs include mesogenjacketed LCPs(MJLCPs),dendronized LCPs,and LC networks(LCNs).

关键词： backbone chains Crystalline

Influence of substrate metals on the crystal growth of AlN films

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2010年第1期17卷 98-103页

作者： Juan Xiong hao-shuang Gu Kuan hu Ming-zhe hu School of Physics and Electronic Technology Hubei University Wuhan 430062 China

AlN films were deposited by reactive radio frequency （RF） sputtering on various bottom electrodes, such as Al, Ti, Mo, Au/Ti, and Pt/Ti. The effects of substrate metals on the orientation of AlN thin films were investigated. The results of X-ray diffraction, atomic force microscopy, and field emission scanning electron microscopy show that the orientation of AlN films depends on the kinds of substrate metals evidently. The differences of AlN films deposited on various metal electrodes are attributed to the differences in lattice mismatch and thermal expansion coefficient between the AlN material and substrate metals. The AlN film deposited on the Pt/Ti electrode reveals highly the c-axis orientation with well-textured columnar structure. The positive role of the Pt/Ti electrode in achieving the high-quality AlN films and high-performance film bulk acoustic resonator （FBAR） may be attributed to the smaller lattice mismatch as well as the similarity of thermal expansion coefficient between the deposited AlN material and the Pt/Ti electrode substrate.

关键词： AlN films substrate orientation crystallinity

A Ruin Model with Compound Poisson Income and Dependence Between Claim Sizes and Claim Intervals

在线全文

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2015年第2期31卷 445-452页

作者： Yuan-yuan hao hu YANG Department of Statistics and Actuarial Science Chongqing University College of Mathematics Chongqing Normal University

We consider a ruin model with random income and dependence between claim sizes and claim intervals. In this paper, we extend the determinate premium income into a compound Poisson process and assume that the distribution of the time between two claim occurrences depends on the previous claim *** the premium size is exponentially distributed, the（Gerber-Shiu） discounted penalty functions is ***, we consider a similar model.

关键词： discounted penalty function laplace transform ruin model dependence

Weakly magnetic field-assisted synthesis of magnetite nano-particles in oxidative co-precipitation

在线全文

学校读者我要写书评

暂无评论

Particuology 2009年第5期7卷 363-367页

作者： Dawei hu Yanmin Wang qi Song College of Materials Science and Engineering South China University of Technology 510640 Guangzhou China Key Laboratory of Special Functional Materials under Ministry of Education 510640 Guangzhou China

This paper presents experimental results on weakly magnetic field-assisted synthesis of magnetite （Fe3O4） nano-particles in an oxidative co-precipitation method, in comparison to the case without magnetic induction. The XRD results show that a weakly magnetic induction below 220 Gs could accelerate the phase transformation from goethite （α-FeOOH） to magnetite （Fe3O4）, and affect the crystal structure, the particle size/morphology and magnetic response of the magnetite nano-particles synthesized. In addition, a higher concentration of the FeCl2 solution in the synthesis reaction led to finer particles, both with and without magnetic induction.

关键词： Magnetic field Oxidative co-precipitation Nano-particle Magnetite Morphology

Finite element model simulation and back propagation neural network modeling of void closure for an extra-thick plate during gradient temperature rolling

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2024年第9期31卷 2236-2247页

作者： Shun-hu Zhang Wen-hao Tian Li-zhi Che Wei-jian Chen Yan Li Liang-wei Wan Zi-qi Yin Shagang School of Iron and Steel Soochow UniversitySuzhou215021JiangsuChina

The void closure behavior in a central extra-thick plate during the gradient temperature rolling was simulated and a back propagation(BP)neural network model was *** thermal–mechanical finite element model of the gradient temperature rolling process was first developed and *** prediction error of the model for the rolling force is less than 2.51%,which has provided the feasibility of imbedding a defect in *** on the relevant data obtained from the simulation,the BP neural network was used to establish a prediction model for the compression degree of a void *** statistical analysis,80%of the data had a hit rate higher than 95%,and the hit rate of all data was higher than 90%,which indicates that the BP neural network can accurately predict the compression ***,the comparisons between the results with the gradient temperature rolling and uniform temperature rolling,and between the results with the single-pass rolling and multi-pass rolling were discussed,which provides a theoretical reference for developing process parameters in actual production.

关键词： BP neural network Finite element model Gradient temperature rolling Void defect Extra-thick plate

Isometric Embeddings of Subsets of Boundaries of Teichmüller Spaces of Compact Hyperbolic Riemann Surfaces

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2020年第5期36卷 605-619页

作者： Guang Ming hu Yi qi College of Science Jinling Institute of TechnologyNanjing 211169P.R.China LMIB and School of Mathematics and Systems Science Beihang UniversityBeijing 100191P.R.China

It is known that every finitely unbranched holomorphic covering π:S→S of a compact Riemann surface S with genus g≥2 induces an isometric embedding Φπ:Teich(S)→Teich(S).By the mutual relations between Strebel rays in Teich(S)and their embeddings in Teich(S),we show that the 1 st-strata space of the augmented Teichmüller space Teich(S)can be embedded in the augmented Teichmüller space Teich(S)***,we show that Φπ induces an isometric embedding from the set Teich(S)B(∞)consisting of Busemann points in the horofunction boundary of Teich(S)into Teich(S)B(∞)with the detour metric.

关键词： Teichmüller space augmented Teichmüller space Strebel ray Busemann points

Microstructure and Thermoelectric Properties of Bi- and Cu-Substituted Ca_3Co_4O_9 Oxides

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2009年第1期25卷 105-108页

作者： haoshan hao Limin Zhao Xing hu Department of Mathematical and Physical Sciences Henan Institute of Engineering Zhengzhou 451191 China School of Physical Engineering and Material Physics Laboratory Zhengzhou University Zhengzhou 450052 China

Bi- and Cu-substituted Ca3Co4O9 samples were prepared by conventional solid-state reaction method and the effect of element substitution on the microstructures and thermoelectric properties was investigated. Partial substitution of Cu for Co leads to an increase in electrical conductivity and a decrease in Seebeck coefficient due to the rise of hole concentration. The microstructure of Cu-substituted sample is almost unchanged compared with undoped Ca3Co4O9. On the other hand, partial substitution of Bi for Ca gives rise to a significant increase in the grain size, and c-axis-oriented structure can be formed in Ca2.7Bi0.3Co4O9, resulting in an obvious increase in electrical conductivity. Cu and Bi co-substitution further increases the grain growth and the electrical conductivity of Ca2.7Bi0.3Co3.7Cu0.3O9. Thus, Cu and Bi co-substitution samples possess the optimal thermoelectric performance at high temperature and the highest value of power factor can reach 3.1×10^-4 Wm^-1.K^-2 at 1000 K.

关键词： Ca3Co4O9 Element substitution Microstructure Thermoelectric properties

Classification using wavelet packet decomposition and support vector machine for digital modulations

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Engineering and Electronics 2008年第5期19卷 914-918页

作者： Zhao Fucai hu Yihua hao Shiqi Hefei Inst. of Electronic Engineering Hefei 230037 P. R. China

To make the modulation classification system more suitable for signals in a wide range of signal to noise rate （SNR）, a feature extraction method based on signal wavelet packet transform modulus maxima matrix （WPTMMM） and a novel support vector machine fuzzy network （SVMFN） classifier is presented. The WPTMMM feature extraction method has less computational complexity, more stability, and has the preferable advantage of robust with the time parallel moving and white noise. Further, the SVMFN uses a new definition of fuzzy density that incorporates accuracy and uncertainty of the classifiers to improve recognition reliability to classify nine digital modulation types （i.e. 2ASK, 2FSK, 2PSK, 4ASK, 4FSK, 4PSK, 16QAM, MSK, and OQPSK）. Computer simulation shows that the proposed scheme has the advantages of high accuracy and reliability （success rates are over 98% when SNR is not lower than 0dB）, and it adapts to engineering applications.

关键词： modulation classification wavelet packet transform modulus maxima matrix support vector machine,fuzzy density.