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Search Results: 1 - 10 of 32912 matches for " Haichao Guo "
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Frequency Measurement of Transient Oscillatory on LABVIEW  [PDF]
Haichao Guo
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.24090
Abstract: Due to the sensitivity of the frequency measurement of power system transient oscillatory signal with respect to noise signal, a new measurement method based on Wavelet Transform and Windowed Fourier Transform is proposed. An analysis using LabVIEW on oscillatory signal containing various noise components is carried on and it is shown that the proposed method can detect the oscillatory frequency more accurately and quickly.
Identification of transcription factors potential related to brown planthopper resistance in rice via microarray expression profiling
Wang Yubing,Guo Huimin,Li Haichao,Zhang Hao
BMC Genomics , 2012, DOI: 10.1186/1471-2164-13-687
Abstract: Background Brown planthopper (BPH), Nilaparvata lugens St l, is one of the most destructive insect pests of rice. The molecular responses of plants to sucking insects resemble responses to pathogen infection. However, the molecular mechanism of BPH-resistance in rice remains unclear. Transcription factors (TF) are up-stream regulators of various genes that bind to specific DNA sequences, thereby controlling the transcription from DNA to mRNA. They are key regulators for transcriptional expression in biological processes, and are probably involved in the BPH-induced pathways in resistant rice varieties. Results We conducted a microarray experiment to analyze TF genes related to BPH resistance in a Sri Lankan rice cultivar, Rathu Heenati (RHT). We compared the expression profiles of TF genes in RHT with those of the susceptible rice cultivar Taichun Native 1 (TN1). We detected 2038 TF genes showing differential expression signals between the two rice varieties. Of these, 442 TF genes were probably related to BPH-induced resistance in RHT and TN1, and 229 may be related to constitutive resistance only in RHT. These genes showed a fold change (FC) of more than 2.0 (P<0.05). Among the 442 TF genes related to BPH-induced resistance, most of them were readily induced in TN1 than in RHT by BPH feeding, for instance, 154 TF genes were up-regulated in TN1, but only 31 TF genes were up-regulated in RHT at 24 hours after BPH infestation; 2–4 times more TF genes were induced in TN1 than in RHT by BPH. At an FC threshold of >10, there were 37 induced TF genes and 26 constitutive resistance TF genes. Of these, 13 were probably involved in BPH-induced resistance, and 8 in constitutive resistance to BPH in RHT. Conclusions We explored the molecular mechanism of resistance to BPH in rice by comparing expressions of TF genes between RHT and TN1. We speculate that the level of gene repression, especially for early TF genes, plays an important role in the defense response. The fundamental point of the resistance strategy is that plants protect themselves by reducing their metabolic level to inhibit feeding by BPH and prevent damage from water and nutrient loss. We have selected 21 TF genes related to BPH resistance for further analyses to understand the molecular responses to BPH feeding in rice.
Accurate detection of moving targets via random sensor arrays and Kerdock codes
Thomas Strohmer,Haichao Wang
Mathematics , 2013, DOI: 10.1088/0266-5611/29/8/085001
Abstract: The detection and parameter estimation of moving targets is one of the most important tasks in radar. Arrays of randomly distributed antennas have been popular for this purpose for about half a century. Yet, surprisingly little rigorous mathematical theory exists for random arrays that addresses fundamental question such as how many targets can be recovered, at what resolution, at which noise level, and with which algorithm. In a different line of research in radar, mathematicians and engineers have invested significant effort into the design of radar transmission waveforms which satisfy various desirable properties. In this paper we bring these two seemingly unrelated areas together. Using tools from compressive sensing we derive a theoretical framework for the recovery of targets in the azimuth-range-Doppler domain via random antennas arrays. In one manifestation of our theory we use Kerdock codes as transmission waveforms and exploit some of their peculiar properties in our analysis. Our paper provides two main contributions: (i) We derive the first rigorous mathematical theory for the detection of moving targets using random sensor arrays. (ii) The transmitted waveforms satisfy a variety of properties that are very desirable and important from a practical viewpoint. Thus our approach does not just lead to useful theoretical insights, but is also of practical importance. Various extensions of our results are derived and numerical simulations confirming our theory are presented.
Uncertainty Principles in Finitely generated Shift-Invariant Spaces with additional invariance
Romain Tessera,Haichao Wang
Mathematics , 2011,
Abstract: We consider finitely generated shift-invariant spaces (SIS) with additional invariance in $L^2(\R^d)$. We prove that if the generators and their translates form a frame, then they must satisfy some stringent restrictions on their behavior at infinity. Part of this work (non-trivially) generalizes recent results obtained in the special case of a principal shift-invariant spaces in $L^2(\R)$ whose generator and its translates form a Riesz basis.
Revisiting Bayesian Blind Deconvolution
David Wipf,Haichao Zhang
Computer Science , 2013,
Abstract: Blind deconvolution involves the estimation of a sharp signal or image given only a blurry observation. Because this problem is fundamentally ill-posed, strong priors on both the sharp image and blur kernel are required to regularize the solution space. While this naturally leads to a standard MAP estimation framework, performance is compromised by unknown trade-off parameter settings, optimization heuristics, and convergence issues stemming from non-convexity and/or poor prior selections. To mitigate some of these problems, a number of authors have recently proposed substituting a variational Bayesian (VB) strategy that marginalizes over the high-dimensional image space leading to better estimates of the blur kernel. However, the underlying cost function now involves both integrals with no closed-form solution and complex, function-valued arguments, thus losing the transparency of MAP. Beyond standard Bayesian-inspired intuitions, it thus remains unclear by exactly what mechanism these methods are able to operate, rendering understanding, improvements and extensions more difficult. To elucidate these issues, we demonstrate that the VB methodology can be recast as an unconventional MAP problem with a very particular penalty/prior that couples the image, blur kernel, and noise level in a principled way. This unique penalty has a number of useful characteristics pertaining to relative concavity, local minima avoidance, and scale-invariance that allow us to rigorously explain the success of VB including its existing implementational heuristics and approximations. It also provides strict criteria for choosing the optimal image prior that, perhaps counter-intuitively, need not reflect the statistics of natural scenes. In so doing we challenge the prevailing notion of why VB is successful for blind deconvolution while providing a transparent platform for introducing enhancements.
Non-Uniform Blind Deblurring with a Spatially-Adaptive Sparse Prior
Haichao Zhang,David Wipf
Computer Science , 2013,
Abstract: Typical blur from camera shake often deviates from the standard uniform convolutional script, in part because of problematic rotations which create greater blurring away from some unknown center point. Consequently, successful blind deconvolution requires the estimation of a spatially-varying or non-uniform blur operator. Using ideas from Bayesian inference and convex analysis, this paper derives a non-uniform blind deblurring algorithm with several desirable, yet previously-unexplored attributes. The underlying objective function includes a spatially adaptive penalty which couples the latent sharp image, non-uniform blur operator, and noise level together. This coupling allows the penalty to automatically adjust its shape based on the estimated degree of local blur and image structure such that regions with large blur or few prominent edges are discounted. Remaining regions with modest blur and revealing edges therefore dominate the overall estimation process without explicitly incorporating structure-selection heuristics. The algorithm can be implemented using a majorization-minimization strategy that is virtually parameter free. Detailed theoretical analysis and empirical validation on real images serve to validate the proposed method.

Huang Chun,Zhang Haichao,Wen Jinhui,Guo Bing,Lai Tianshu,Lin Weizhu,

光子学报 , 1999,
Abstract: Ultrafast heavy hole relaxation in Si doped GaAs is studied using femtosecond absorption saturation measurements with an exciting photon energy of 1.52eV to produce electron states in the vicinity of the doped electron Fermi edge at room temperature.A heavy hole thermalization time of about 300fs is measured and is attributed to the heavy hole optical phonon scattering.An optical deformation potential of d 0(31eV) is estimated,which may reflects the influences of dopants on the HH nonpolar optical phonon interaction.

LIN Haichao,

腐蚀科学与防护技术 , 1997,
Abstract: The results of research on inhibitors and their action mechanisms in recent years were reviewed. The following aspects were mainly discussed: the inhibitive action mechanism of inhibitors for SCC, the inhibitive action of thiourea and its derivatives, cinnamyl aldehyde in acidic medium as well as inhibition behaviors of inhibitors for amorphous alloys. Finally the application of inhibitors in chemical power source and rust resistant technology and the results of investigation on corrosion inhibition by using SERS and STM were outlined, and also the testing and evaluation technology were summarized.

YAN Chuanwei,LI Ying,SONG Guangling,CAO Chu'nan,LIN Haichao,GUO Liping,LIN Xiangqin,

腐蚀科学与防护技术 , 1999,
Abstract: Vapor deposited (TPP)H 2 film on iron was investigated by means of XPS, SEM, STM and potentiodynamic measurement. It was found that a well distributed deposited film as base layer was formed at initial stage, then growth of the film on the base layer in particle form. The film is composed of a physically adsorbed outer layer and chemically bonded inner layer of (TPP)H 2. The outer layer can be easily removed by DMF solvent. However, Iron porphyrin could not be found on the treated sample surfaces. A model about the structure and composition of the(TPP)H 2 deposited film is put forward.
Research Electricity Production Costs and External Compensation Mechanism  [PDF]
Dunnan Liu, Xinming Liu, Liaoyi Ning, Haichao Wang, Yu Hu, Yujie Xu
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.24015
Abstract: China's power enterprises are mainly dominated by thermal power, thermal power is the key industry of coal consumption, so the thermal power enterprises have a fundamental influence on the environment, and how to not affect the vital interests of power enterprises under the condition of power plant to increase the strength of governance is to solve the current problem of letter. On the basis of various types of power generation enterprise environmental cost of thermal power, hydropower, wind power and nuclear power pollutant treatment cost were described, through the analysis of emission control scheme and the cost compensation of pollutants, environmental governance cost model, using a actual plant data, calculation of various pollutants compensation cost of thermal power plant, and according to the thermal power and wind power for quantitative comparison before and after compensation.
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