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Search Results: 1 - 10 of 13751 matches for " Du Huan "
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The Price Forecasting of Military Aircraft Based on SVR  [PDF]
Jifeng Tong, Jiaxing Du, Ping Chen, Jianguang Yuan, Zhan Huan
Journal of Computer and Communications (JCC) , 2015, DOI: 10.4236/jcc.2015.35030
Abstract:

The difficulty of the prediction of military aircraft purchase price lies in the small sample data, and the sample data have the complicated non-linear characteristics. By analyzing the influence of parameters of aircraft purchase price, SVR is proposed to predict the aircraft purchasing price model, and uses the model to predict the aircraft purchase price. The calculation results show that the prediction of the purchase price to establish military aircraft model has higher prediction accuracy.

Robots Learn Writing
Huan Tan,Qian Du,Na Wu
Journal of Robotics , 2012, DOI: 10.1155/2012/505191
Abstract: This paper proposes a general method for robots to learn motions and corresponding semantic knowledge simultaneously. A modified ISOMAP algorithm is used to convert the sampled 6D vectors of joint angles into 2D trajectories, and the required movements for writing numbers are learned from this modified ISOMAP-based model. Using this algorithm, the knowledge models are established. Learned motion and knowledge models are stored in a 2D latent space. Gaussian Process (GP) method is used to model and represent these models. Practical experiments are carried out on a humanoid robot, named ISAC, to learn the semantic representations of numbers and the movements of writing numbers through imitation and to verify the effectiveness of this framework. This framework is applied into training a humanoid robot, named ISAC. At the learning stage, ISAC not only learns the dynamics of the movement required to write the numbers, but also learns the semantic meaning of the numbers which are related to the writing movements from the same data set. Given speech commands, ISAC recognizes the words and generated corresponding motion trajectories to write the numbers. This imitation learning method is implemented on a cognitive architecture to provide robust cognitive information processing. 1. Introduction Robots are expected to generate human-like behaviors in dynamic environments [1, 2]. However, it is very difficult for robots to develop skills or behaviors totally from scratch without any initial knowledge. As stated in Sloman’s paper, robots should learn both altricial and precocial behaviors after their “birth” [3]. Therefore, it is reasonable that robots have some basic and simple initial knowledge with motion primitives [4], or some basic and simple initial skills to explore the world to develop new knowledge and skills to survive or complete tasks. Upon these initial knowledge and skills, humans can teach robots more complex behaviors or skills to complete much more complex tasks. Imitation learning (also called learning from demonstration, programming by demonstration) is now considered as a powerful tool for transferring skills between robots (especially humanoid robots) [5]. Unlike the traditional teaching-executing mode, where robots simply record the trajectory programmed by human operators and move the angles and end effector along the trajectory, since 1970s, the researchers had tried to train robots to learn simple motion patterns [6]. In 1980s, Atkeson trained a robot to learn how to balance an inverted pendulum in an upright position through practice [7].
Power Distribution Strategy Considering Active Power Loss for DFIGs Wind Farm  [PDF]
Xiao Du, Yigong Zhang, Zhiqiang Dai, Huan Liu, Siming Wei, Jin Liu
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.24030
Abstract: With the development of concentrated wind power areas, new energy’s dispatching problems are more prominent with its fast expansion. However, we can maximize the utilization of wind power under power curtailment conditions by optimal wind power dispatching. The paper studies on the basic theories of wind power turbines, and analyses the power’s control and output characteristics of wind turbine, which analyses the double-fed inductor generator’s excellent decoupling control of power and its excellent reactive power output capability. By studying the characteristics of wind power output, this paper provides a strategy for optimal dispatch in wind power generation. The calculation results show that the total active and reactive power output of the wind farm match the request of dispatch center. And the total active loss and total reactive loss is the least in the meantime.
Effects of Long-Term Fertilization on Organic Carbon and Nitrogen Dynamics in a Vertisol in Eastern China  [PDF]
Wei Li, Huan Chen, Chengfu Cao, Zhu Zhao, Yuqiang Qiao, Shizhou Du
Open Journal of Soil Science (OJSS) , 2018, DOI: 10.4236/ojss.2018.83008
Abstract: Mineral fertilizers and organic amendment can affect the various soil organic matter (SOM) pools and the distribution of organic carbon (OC) and nitrogen (N) in these pools. It is unknown how OC and N are distributed in different SOM pools under different long-term fertilization regimes. Therefore, this study aimed to examine the effects on OC and N concentrations in various SOM pools after 33 years of application of chemical fertilizer and organic amendment in Anhui Province in the Huang-Huai-Hai Plain, eastern China. This long-term experiment consisted of five fertilization treatments measuring changes in the OC and N concentrations in the soils and different SOM fractions of each experiment plot. Organic amendment increased the OC and N concentrations in the mineral-associated fraction, the coarse mineral-associated fraction and the aggregates compared with the values obtained without fertilizer application. Mineral fertilizer application alone increased the abovementioned indexes, but this increase was small. There was a small but significant increase in the OC and N concentrations in the free particulate fraction, and the change in magnitude had no obvious effect on the total OC (TOC) and total N (TN) concentrations in soils. More than 80% of the water-stable aggregate-associated C was stored in macroaggregates >2 mm in size. More than 60% of the TOC and TN accumulated within mineral associations in the soil, and organic amendment increased this proportion to 80%. These results suggest that the OC in Vertisols is dominated by mineral-associated OC and that the effect of organic amendment on mineral-associated OC is obvious.
Analysis of a Large Grounding System and Subsequent Field Test Validation Using the Fall of Potential Method  [PDF]
Huan Huang, Hualin Liu, Hong Luo, Hao Du, Yi Xing, Yexu Li, Farid P. Dawalibi, Haijun Zhou, Longhai Fu
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B240
Abstract:

This paper examines various aspects of the design process and subsequent field test measurements of a large and complex substation grounding system. The study and measurements show that soil layering and lead interference can have a significant impact on the appropriate test location that yields the exact substation ground impedance. Applying a specific percentage rule such as the 61.8% rule for uniform soils to obtain the true ground impedance may lead to unacceptable errors for large grounding systems. This poses significant problems when attempting to validate a design based on raw test data that are interpreted using approximate methods to evaluate substation ground impedance, and determine ground potential rise (GPR), touch and step voltages. Advanced measurement methodologies and modern software packages were used to obtain and effectively analyze fall of potential test data, compute fault current distribution, and evaluate touch and step voltages for this large substation. Fault current distribution between the grounding system and other metallic paths were computed to determine the portion of fault current discharged in the grounding system. The performance of the grounding system, including its GPR and touch and step voltages, has been accurately computed and measured, taking into account the impedance of the steel material used of the ground conductors and circulating currents within the substation grounding system.

The Complete Mitochondrial Genome of the Pink Stem Borer, Sesamia inferens, in Comparison with Four Other Noctuid?Moths
Huan-Na Chai,Yu-Zhou Du
International Journal of Molecular Sciences , 2012, DOI: 10.3390/ijms130810236
Abstract: The complete 15,413-bp mitochondrial genome (mitogenome) of Sesamia inferens (Walker) (Lepidoptera: Noctuidae) was sequenced and compared with those of four other noctuid moths. All of the mitogenomes analyzed displayed similar characteristics with respect to gene content, genome organization, nucleotide comparison, and codon usages. Twelve-one protein-coding genes (PCGs) utilized the standard ATN, but the cox1 gene used CGA as the initiation codon; cox1, cox2, and nad4 genes had the truncated termination codon T in the S. inferens mitogenome. All of the tRNA genes had typical cloverleaf secondary structures except for trnS1(AGN), in which the dihydrouridine (DHU) arm did not form a stable stem-loop structure. Both the secondary structures of rrnL and rrnS genes inferred from the S. inferens mitogenome closely resembled those of other noctuid moths. In the A+T-rich region, the conserved motif “ATAGA” followed by a long T-stretch was observed in all noctuid moths, but other specific tandem-repeat elements were more variable. Additionally, the S. inferens mitogenome contained a potential stem-loop structure, a duplicated 17-bp repeat element, a decuplicated segment, and a microsatellite “(AT) 7”, without a poly-A element upstream of the trnM in the A+T-rich region. Finally, the phylogenetic relationships were reconstructed based on amino acid sequences of mitochondrial 13 PCGs, which support the traditional morphologically based view of relationships within the Noctuidae.
Electrosynthesis of poly(o-phenylenediamine) in ionic liquid and its properties
YanFang Du,Huan Wang,AiJian Zhang,JiaXing Lu
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0331-9
Abstract: Ionic liquid 1-ethyl-3-methylimidazolium bromide ([EMIM]Br) and N-methylimidazolium tetrafluoroborate ([HMIM]BF4) have been used as solvent and electrolyte for the electropolymerization of o-phenylenediamine at glassy carbon electrode by cyclic voltammetry. It was found that monomer was more easily oxidized in ionic liquid than acidic aqueous solution, and oxidative potential was reduced by 0.725 and 0.455 V, respectively. Electrode modified with poly(o-phenylenediamine) (PPD) has obvious electrochemical activity in acid solution (pH 1–4). The apparent diffusion coefficient (D app) of PPD film is measured by chronocoulometry and chronoamperometry. The polymer structure is measured by UV and IR. IR spectrometry reveals that poly(o-phenylenediamine) has phenazine ring structure. The heat stability of polymer is observed from thermogravimetry.
NONLINEAR THEORY OF PHOTOACOUSTIC EFFECT OF RESTRICTED BEAM
非线性有限束光声效应理论

DU GONG-HUAN,
杜功焕

物理学报 , 1988,
Abstract: When a chopped light impinges on a solid sample in an photoacoustic cell, an acoustic signal is produced not only with the fundamental but also with the second harmonic component because of the nonlinear photoacoustic effect. An equation of nonlinear thermal wave beam is presented with nonlinear boundary conditions and solved by using the perturbation approach method under the case that the light source has a Gaussian profile. The Hankel transformation is utilized to attain the first and second order approximation solutions of the equation.The analytic results show that the thermal wave beam of second harmonic still maintains the Gaussian profile with a smaller Gaussian radius than that of the fundamental component and also the amplitude of the second harmonic relates with not only the linear but also the nonlinear thermal parameters which might be expected to provide more information from the sample than the linear one.Basing on these vesults, a new nonlinear paotoacoustic technique would be expected to develop.
NONLINEAR THEORY OF DISTORTION OF BOUNDED ULTRA- SONIC BEAM IN RELAXATING MEDIA
弛豫媒质中有限束超声波的非线性传播畸变理论

DU GONG-HUAN,
杜功焕

物理学报 , 1989,
Abstract: In this article, a nonlinear wave equation of bounded acoustic beam in relaxating media is presented and a general solution of higher harmonics resulting from the nonlinear distortion of propagation is found by using the pertubation approach. Investigation shows that for the Gaussian ultrasonic field, the solution of higher harmonics can be given analytically, moreover their corresponding radical distributions of amplitude always maintain the Gaussian profiles. Although the dispersion may affect the amplitude of various harmonics, the variation of phase velocity of those keep the same law as the small amplitude waves of corresponding frequencies do.We also show that by means of Blackstock' operator the obtained results can be applied te the case of media with arbitrary dissipation and dispersion, including some biomedia in which the relationship between the absorption and frequency may be obtained only empirically.
An analytical model for the surface electrical field distribution of LDMOSFETs with shield rings
具有屏蔽环结构的LDMOS漂移区表面电场分布模型

Chen Lei,Du Huan,
陈蕾
,杜寰

半导体学报 , 2011,
Abstract: An analytical model of an LDMOSFET with a shield ring is established according to the 2D Poisson equation. Surface electrical field distribution along the drift region is obtained from this model and the influence of shield length and oxide thickness on the electrical field distribution is studied. The robustness of this model is verified using ISE TCAD simulation tools. The breakdown voltage of a specific device is also calculated and the result is in good agreement with experimental data.
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