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匹配条件: “Dou Yangyang” ,找到相关结果约1359条。
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Effect of Variable Sulfur Supply on Thiol Compounds and Arsenic Accumulation in Kandelia Obovata (S., L.) Yong Seedlings  [PDF]
Dou Yangyang, Wu Guirong
Open Access Library PrePrints (OALib PrePrints) , 2014, DOI: 10.4236/oalib.preprints.1200091
Abstract: In the present study, Kandelia obovata (S., L.) Yong seedlings were exposed to As V(0, 30, 60 and 150 mg kg-1) under different levels of sulfur (0, 0.1, 0.2 and 0.4% (w: w)) supply. A highly significant negative correlation between arsenic concentration in leaves with sulfur treatment (r=-0.554, P<0.01) is established. Concentration of arsenic in roots proves much higher than that in leaves. The GSH concentrations in K. obovata seedlings show significantly increases (rleave=0.648, rroot=0.602; P<0.01) with increasing sulfur supply in the growth media. Arsenic induced GSH formation in leaves of K. obovata seedlings, and clearly restrained GSH formation in roots. Arsenic exposure significantly increased the synthesis of non-protein thiols (NPT). Supply of sulfur at 0.1% and 0.2% promoted the content of NPT (P<0.05), but at 0.4% sulfur there was little effect on the NPT content (P>0.05). In conclusion, an increase in sulfur supply to plants may improve their accumulation capacity for arsenic through enhanced tolerance caused by a positive effect on the thiol metabolism of the plants.
Higher Order Iteration Schemes for Unconstrained Optimization  [PDF]
Yangyang Shi, Pingqi Pan
American Journal of Operations Research (AJOR) , 2011, DOI: 10.4236/ajor.2011.13011
Abstract: Using a predictor-corrector tactic, this paper derives new iteration schemes for unconstrained optimization. It yields a point (predictor) by some line search from the current point; then with the two points it constructs a quadratic interpolation curve to approximate some ODE trajectory; it finally determines a new point (corrector) by searching along the quadratic curve. In particular, this paper gives a global convergence analysis for schemes associated with the quasi-Newton updates. In our computational experiments, the new schemes using DFP and BFGS updates outperformed their conventional counterparts on a set of standard test problems.
Discursive Metaphors Analysis: The Love Metaphor of Plant in Chinese Love Poetry
Yangyang ZHANG
Cross-Cultural Communication , 2012, DOI: 10.3968/j.ccc.1923670020120805.2022
Abstract: A conceptual metaphor may have various meanings in different languages, and usually contains cultural background. Based on cognitive approach, this paper aims to study Chinese metaphor through analyzing four conceptual metaphors of four typical plants in traditional Chinese poetry. This article also discusses why these ancient metaphors can still be used commonly in modern Chinese language. At the same time, through analyzing these metaphors, relevant implicating Chinese cultural aspects are described. Key words: Discursive metaphor; Ancient Chinese poetry; Love; Plant
Alternating proximal gradient method for sparse nonnegative Tucker decomposition
Yangyang Xu
Mathematics , 2013,
Abstract: Multi-way data arises in many applications such as electroencephalography (EEG) classification, face recognition, text mining and hyperspectral data analysis. Tensor decomposition has been commonly used to find the hidden factors and elicit the intrinsic structures of the multi-way data. This paper considers sparse nonnegative Tucker decomposition (NTD), which is to decompose a given tensor into the product of a core tensor and several factor matrices with sparsity and nonnegativity constraints. An alternating proximal gradient method (APG) is applied to solve the problem. The algorithm is then modified to sparse NTD with missing values. Per-iteration cost of the algorithm is estimated scalable about the data size, and global convergence is established under fairly loose conditions. Numerical experiments on both synthetic and real world data demonstrate its superiority over a few state-of-the-art methods for (sparse) NTD from partial and/or full observations. The MATLAB code along with demos are accessible from the author's homepage.
Alternating proximal gradient method for nonnegative matrix factorization
Yangyang Xu
Mathematics , 2011,
Abstract: Nonnegative matrix factorization has been widely applied in face recognition, text mining, as well as spectral analysis. This paper proposes an alternating proximal gradient method for solving this problem. With a uniformly positive lower bound assumption on the iterates, any limit point can be proved to satisfy the first-order optimality conditions. A Nesterov-type extrapolation technique is then applied to accelerate the algorithm. Though this technique is at first used for convex program, it turns out to work very well for the non-convex nonnegative matrix factorization problem. Extensive numerical experiments illustrate the efficiency of the alternating proximal gradient method and the accleration technique. Especially for real data tests, the accelerated method reveals high superiority to state-of-the-art algorithms in speed with comparable solution qualities.
On the convergence of higher-order orthogonality iteration
Yangyang Xu
Mathematics , 2015,
Abstract: The higher-order orthogonality iteration (HOOI) has been popularly used for finding a best low-multilinear-rank approximation of a tensor. However, its iterate sequence convergence is still an open question. In this paper, we first analyze a greedy HOOI, which updates each factor matrix by selecting from the best candidates one that is closest to the current iterate. Assuming the existence of a block-nondegenerate limit point, we establish its global convergence through the so-called Kurdyka-Lojasiewicz (KL) property. In addition, we show that if the starting point is sufficiently close to any block-nondegenerate globally optimal solution, the greedy HOOI produces a sequence convergent to a globally optimal solution. Relating the iterate sequence by the original HOOI to that by the greedy HOOI, we then show that the same convergence results hold for the original HOOI and thus positively address the open question.
On Higher-order Singular Value Decomposition from Incomplete Data
Yangyang Xu
Computer Science , 2014,
Abstract: Higher-order singular value decomposition (HOSVD) is an efficient way for data reduction and also eliciting intrinsic structure of multi-dimensional array data. It has been used in many applications, and some of them involve incomplete data. To obtain HOSVD of the data with missing values, one can first impute the missing entries through a certain tensor completion method and then perform HOSVD to the reconstructed data. However, the two-step procedure can be inefficient and does not make reliable decomposition. In this paper, we formulate an incomplete HOSVD problem and combine the two steps into solving a single optimization problem, which simultaneously achieves imputation of missing values and also tensor decomposition. We also present two algorithms for solving the problem based on block coordinate update. Global convergence of both algorithms is shown under mild assumptions. The convergence of the second algorithm implies that of the popular higher-order orthogonality iteration (HOOI) method, and thus we, for the first time, give global convergence of HOOI. In addition, we compare the proposed methods to state-of-the-art ones for solving incomplete HOSVD and also low-rank tensor completion problems and demonstrate the superior performance of our methods over other compared ones. Furthermore, we apply them to face recognition and MRI image reconstruction to show their practical performance.
The Problems and Reform of Art and Design Education in Colleges and Universities in China  [PDF]
Xiangdong Dou
Creative Education (CE) , 2015, DOI: 10.4236/ce.2015.620227
Abstract: The modern art education was originated from Germany Faculty of Bauhaus, dating back more than 100 years, while our art and design education is still at primary stage, only with a history of 50 years. But we are enjoying a good development trend in art and design education and it develops fast. In such a fast developmental course, it is inevitable to produce various problems. This paper mainly analyzed the problems in art and design education in our colleges and universities and put forward some feasible reform programs.
A QoE Assessment System in Distance Education  [PDF]
Dengyin Zhang, Yangyang Xu, Chunling Cheng
Engineering (ENG) , 2011, DOI: 10.4236/eng.2011.31011
Abstract: It is a challenging task to improve the real-time property and objectivity of the effect assessment for the distance education. This paper presents a QoE (Quality of Experience) assessment system based on the attention of online user. The system captures the video frames from two cameras periodically and synchronously, using the adaptive image binarization based on the linear average threshold for the pretreatment, then processing with edge detection and filtering in the cross-directions at the same time. System gets the position of computer screen and user eyeball. Analyzing the detection results comprehensively obtains the attention of online user by some judging conditions, and finally acquires the quality of user experience. Experimental results demonstrate the feasibility and efficiency.
Research on the Market Access of Cold Chain Logistics Service Quality Safety for Agricultural Products  [PDF]
Xin’gang Weng, Jiuyi An, Yangyang Hu
Journal of Service Science and Management (JSSM) , 2015, DOI: 10.4236/jssm.2015.86080
Abstract: The cold chain logistics service quality safety of agricultural means that cold chain logistics services must meet requirements relating to human health, safety and quality. It needs to be regulated by law, compulsory supervision and security, which mainly refers to the quality of service safety. From the connotation of the cold-chain logistics service quality safety of agricultural products market access analysis, this article cards the agricultural cold chain logistics service quality safety market access system components and puts forward the system frame of quality safety of agricultural products cold chain logistics service market access policy.
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