OALib Journal期刊

ISSN: 2333-9721




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匹配条件: “Jun ZHANG” ,找到相关结果约124961条。
Remodeling of living human nasal cavity under the assistance of acoustic rhinometry technique  [PDF]
Jun Zhang
Journal of Biosciences and Medicines (JBM) , 2013, DOI: 10.4236/jbm.2013.12007

Acoustic rhinometry could numerically describe up- per airway condition of air draft by drawing a graph plotting the distance from the nostril vs. the cross-sectional area. Some decreases on the graph correspond to the typical anatomic structures of human nasal cavity. The 3-dimensional, computing fluid dynamic model of the same person was developed based on computed tomography scans. The veracity of the CFD model was valued by contrasting the relevant areas of stenosis site between the model and the AR graph. The aim in this study is to make clear how to use an AR to help improve and enrich the CFD model with the information of graph acquired from the measurement. The combination of AR and CT can be used to establish a living human nasal cavity model with higher significant information content.

Characteristic size research of human nasal cavity and the respiratory airflow CFD analysis  [PDF]
Jun Zhang
Journal of Biosciences and Medicines (JBM) , 2013, DOI: 10.4236/jbm.2013.12006

To study the airflow distribution in human nasal cavity during respiration and the characteristic parameters for nasal structure, thirty three-dimensional, anatomically accurate representations of adult nasal cavity models were reconstructed based on processed tomography images collected from normal people. The airflow fields in nasal cavities were simulated using the fluid dynamics with the finite element software ANSYS. The results showed that the difference of human nasal cavity structure led to varying airflow distribution in the nasal cavities and the main airflow passed through the common nasal meatus. The nasal resistance in the regions of nasal valve and nasal vestibule accounted for more than a half of overall resistance. The characteristic model of nasal cavity was extracted based on the characteristic points and dimensions deducted from the original models. It showed that either the geometric structure or the air-flow field of the two kinds of model was similar. The characteristic dimensions were the characteristic parameters of nasal cavity that properly represented the original model in research for nasal cavity.

Animal bone growth experiment of rapid-growing rats in different stress environment and its mathematical model  [PDF]
Jun Zhang, Wenzhi Zhao
Journal of Biosciences and Medicines (JBM) , 2013, DOI: 10.4236/jbm.2013.12005

The aim of this study is to explore a way that quantify the qualitative equation of bone growth and remodeling which was based on the animal Experiment of rapid-growing Rats in Different Stress Environment. These results were proved to be of good stability and identification precision with the numerical method of inversion. It suggested that the growing coefficient and the threshold in function were variables changing with time and space. The idea and method used in the research of bone growth and remodeling adaptation in this paper also provided clue and reference to establish other models for living system.

Apply GPCA to Motion Segmentation  [PDF]
Hongchuan Yu, Jian Jun Zhang
Journal of Intelligent Learning Systems and Applications (JILSA) , 2011, DOI: 10.4236/jilsa.2011.31006
Abstract: In this paper, we present a motion segmentation approach based on the subspace segmentation technique, the genera-lized PCA. By incorporating the cues from the neighborhood of intensity edges of images, motion segmentation is solved under an algebra framework. Our main contribution is to propose a post-processing procedure, which can detect the boundaries of motion layers and further determine the layer ordering. Test results on real imagery have confirmed the validity of our method.
Ancestral Informative Marker Selection and Population Structure Visualization Using Sparse Laplacian Eigenfunctions
Jun Zhang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0013734
Abstract: Identification of a small panel of population structure informative markers can reduce genotyping cost and is useful in various applications, such as ancestry inference in association mapping, forensics and evolutionary theory in population genetics. Traditional methods to ascertain ancestral informative markers usually require the prior knowledge of individual ancestry and have difficulty for admixed populations. Recently Principal Components Analysis (PCA) has been employed with success to select SNPs which are highly correlated with top significant principal components (PCs) without use of individual ancestral information. The approach is also applicable to admixed populations. Here we propose a novel approach based on our recent result on summarizing population structure by graph Laplacian eigenfunctions, which differs from PCA in that it is geometric and robust to outliers. Our approach also takes advantage of the priori sparseness of informative markers in the genome. Through simulation of a ring population and the real global population sample HGDP of 650K SNPs genotyped in 940 unrelated individuals, we validate the proposed algorithm at selecting most informative markers, a small fraction of which can recover the similar underlying population structure efficiently. Employing a standard Support Vector Machine (SVM) to predict individuals' continental memberships on HGDP dataset of seven continents, we demonstrate that the selected SNPs by our method are more informative but less redundant than those selected by PCA. Our algorithm is a promising tool in genome-wide association studies and population genetics, facilitating the selection of structure informative markers, efficient detection of population substructure and ancestral inference.
Geometric method in quantum control
Jun Zhang
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5186-z
Abstract: In this paper we survey the geometric method in quantum control. By presenting a geometric representation of nonlocal two-qubit quantum operation, we show that the control of two-qubit quantum operations can be reduced to a steering problem in a tetrahedron. Two physical examples are given to illustrate this method. We also provide analytic approaches to construct universal quantum circuit from any arbitrary quantum gate.
Global Service Network and the Choices of China
Jun zhang
International Business Research , 2010, DOI: 10.5539/ibr.v3n4p139
Abstract: Global production network has become the main competitive force on the micro level in the process of globalization, which is monopolized by transnational corporations. After the transfer of manufactures from developed countries to developing countries, global transfer turns to service industry, especially the transfer of knowledge intensive services such as financial services, professional services, information services, research and development and technology. The paper constructs global service network as the framework to analyze how knowledge intensive service industry develops in China by involving in the network. It draws the conclusion that by involving in global service network, which incorporates knowledge transfer mechanism, the developing countries can acquire later-comer advantage and develop their industry in some period, but the lock-in trap would be damage to their further development.
Improvement of a Forward-Secure Multi-Proxy Signature Scheme
Jun Zhang
Journal of Networks , 2011, DOI: 10.4304/jnw.6.9.1272-1279
Abstract: This paper shows some insecurities in Xu’s forward secure multi-proxy signature scheme. There are two kinds of attacks on this scheme: (1) anyone can forge some certain messages which to be sign and cannot detect by the signature verifier. (2) This scheme can’t resist the dishonest signer forgery attack by forging its own public key. After that, the paper proposed two new forward-secure multi-proxy signature schemes based on discrete logarithm problem and quadratic residues. With verifying all the signers’ public keys, the improved schemes can resist lots of outsider attack and insider attack as above mentioned. The validity of the new scheme can be verified, and they are secure multi-signature schemes.
An Improved Proxy Multi-Signature, Multi-Proxy Signature and Multi-Proxy Multi-Signature Scheme
Jun Zhang
Journal of Networks , 2011, DOI: 10.4304/jnw.6.8.1238-1245
Abstract: Zhou’s proxy multi-signature scheme was a safe and effective scheme, but this scheme was not safety enough. In this work, security analysis was given to the scheme and results showed that the scheme was very easy aggressed by the forgery attack. The paper proposed that any attacker can sign some certain unauthorized messages after the attacker knows a valid signature, and any original signer ally with his proxy signer can forge any unauthorized messages. Then, the paper gave two kinds of inside attacks and outside attacks to the scheme correspondingly. Finally this paper proposed a new improved proxy multi-signature, multi-proxy signature and multi-proxy multi-signature schemes which based on the difficulty of the discrete logarithm problem (DLP). With verifying all the signers’ public keys, the improved schemes can resist lots of outsider attack and insider attack. The validity of the new scheme can be verified, and they are secure signature schemes.
Nonparametric Information Geometry: From Divergence Function to Referential-Representational Biduality on Statistical Manifolds
Jun Zhang
Entropy , 2013, DOI: 10.3390/e15125384
Abstract: Divergence functions are the non-symmetric “distance” on the manifold, Μθ, of parametric probability density functions over a measure space, ( Χ,μ). Classical information geometry prescribes, on Μθ: (i) a Riemannian metric given by the Fisher information; (ii) a pair of dual connections (giving rise to the family of α-connections) that preserve the metric under parallel transport by their joint actions; and (iii) a family of divergence functions ( α-divergence) defined on Μθ x? Μθ, which induce the metric and the dual connections. Here, we construct an extension of this differential geometric structure from Μθ (that of parametric probability density functions) to the manifold, Μ, of non-parametric functions on X, removing the positivity and normalization constraints. The generalized Fisher information and α-connections on M are induced by an α-parameterized family of divergence functions, reflecting the fundamental convex inequality associated with any smooth and strictly convex function. The infinite-dimensional manifold, M, has zero curvature for all these α-connections; hence, the generally non-zero curvature of M can be interpreted as arising from an embedding of Μθ into Μ. Furthermore, when a parametric model (after a monotonic scaling) forms an affine submanifold, its natural and expectation parameters form biorthogonal coordinates, and such a submanifold is dually flat for α?= ± 1, generalizing the results of Amari’s α-embedding. The present analysis illuminates two different types of duality in information geometry, one concerning the referential status of a point (measurable function) expressed in the divergence function (“referential duality”) and the other concerning its representation under an arbitrary monotone scaling (“representational duality”).

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