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Search Results: 1 - 10 of 127260 matches for " Weijun;Li "
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Global convergence of a regularized factorized quasi-Newton method for nonlinear least squares problems
Zhou, Weijun;Zhang, Li;
Computational & Applied Mathematics , 2010, DOI: 10.1590/S1807-03022010000200006
Abstract: in this paper, we propose a regularized factorized quasi-newton method with a new armijo-type line search and prove its global convergence for nonlinear least squares problems. this convergence result is extended to the regularized bfgs and dfp methods for solving strictly convex minimization problems. some numerical results are presented to show efficiency of the proposed method. mathematical subject classification: 90c53, 65k05.
Research on Barcode Image Binarization in Barcode Positioning System
Weijun Zhang,Dongli Li
International Journal of Computer Science Issues , 2012,
Abstract: Aiming at the disadvantages of the traditional positioning technology, barcode positioning system is introduced in this paper. Based on Otsu method, a novel barcode image binarization is put forward by comparing varieties of image binarization methods domestically and abroad. Moreover, we have a systematic research on histogram and binarization mechanism, and also give the calculation of histogram and derive a formula of Otsu method. Finally, the histogram and binarization of one-dimensional barcode image are realized with the specific examples. After experiments for scanned barcode image, the result has demonstrated effectiveness of the method.
Production of Volatile Compounds in Reconstituted Milk Reduced-Fat Cheese and the Physicochemical Properties as Affected by Exopolysaccharide-Producing Strain
Weijun Wang,Lanwei Zhang,Yanhua Li
Molecules , 2012, DOI: 10.3390/molecules171214393
Abstract: The application of the exopolysaccharide-producing strains for improving the texture and technical properties of reduced-fat cheese looks very promising. Streptococcus thermophilus TM11 was evaluated for production of reduced-fat cheese using reconstituted milk powder (CRMP). The physicochemical analysis of fresh and stored cheeses showed that this strain slightly increased moisture content resulting in cheese with higher yield and lower protein content compared to the direct acidified cheese. The volatiles of cheese were determined by SPME and GC equipped with a mass spectrometer. The results indicated that the major compounds included aldehydes, ketones and acids, whereas, alcohols and branched-chain aldehydes that contribute to exciting and harsh flavors were not found in CRMP. By the textural profile analysis, we found the cheese made with S. thermophilus TM11 had lower cohesiveness, resilience and higher adhesiveness than the direct acidified cheese, and had similar hardness. Further, S. thermophilus TM11 greatly changed the protein matrix with more opened cavities according to observation by scanning electron microscopy. Consequently, use of S. thermophilus TM11 could endow CRMP with the novel and suitable flavor properties and improved texture quality.
Formation of Aldehyde and Ketone Compounds during Production and Storage of Milk Powder
Yanhua Li,Lanwei Zhang,Weijun Wang
Molecules , 2012, DOI: 10.3390/molecules17089900
Abstract: Certain aldehyde and ketone compounds can be used as indicators, at a molecular level, of the oxidized flavor of milk powder instead of sensory evaluation. This study investigated the formation of aldehyde and ketone compounds as affected by the heat-related processing and storage of milk powder. The compounds were extracted by solid phase microextraction fiber and determined using gas chromatography-mass spectrometry. In the results, higher contents of hexanal, 2-heptanone, octanal and 3-octen-2-one were detected in concentrated milk and fresh milk powders than in raw milk and heated milk. The levels of these compounds increased with increasing time of storage of milk powder. Meanwhile, the DPPH radical scavenging activity decreased and peroxide value increased during the production and storage of milk powder. In addition, the pore volume distribution of milk powder particle was determined by nitrogen isotherm adsorption. The porosity of milk powder was significantly correlated to the changes of aldehyde and ketone compounds during storages periods of 3 months (r > 0.689, p < 0.05) and 6 months (r > 0.806, p < 0.01). Therefore attention should be paid to the detectable aldehyde and ketone molecules to control the oxidized flavor, which was influenced by pre-heating as well as concentration and drying during milk powder production.
Dependency based Technique for Identifying the Ripple Effect of Requirements Evolution
YuQing Yan,Shixian Li,Weijun Sun
Journal of Software , 2012, DOI: 10.4304/jsw.7.3.544-550
Abstract: Requirements evolve continuously and inevitably. In order to effectively manage requirements change, an understa- nding from a quantitative perspective is needed in determining the extent of the propagation of the requirements as they evolve. In this paper, we first look back at the impact analysis in the software life cycle and give an overview of requirements dependencies. We present a generic algorithm for identifying requirements dependencies and the definitions that are adopted for this study.Using matrix theory on the requirements dependencies, we present the formulas of the ripple effects of requirements evolution and their properties. A typical example in structured analysis of M.Jackson is described to show the effectiveness of the method presented here.
Chinese Tone and Vowel Processing Exhibits Distinctive Temporal Characteristics: An Electrophysiological Perspective from Classical Chinese Poem Processing
Weijun Li, Lin Wang, Yufang Yang
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0085683
Abstract: Classical Chinese poems have strict regulations on the acoustic pattern of each syllable and are semantically meaningless. Using such poems, this study characterized the temporal order of tone and vowel processing using event-related potentials (ERPs). The target syllable of the poem was either correct or deviated from the correct syllable at tone, vowel or both levels. Vowel violation elicited a negative effect between 300 and 500 ms regardless of the tone correctness, while tone violation elicited a positive effect between 600 and 1000 ms. The results suggest that the vowel information was available earlier than the tone information. Moreover, there was an interaction between the effect of vowel and tone violations between 600 and 1000 ms, showing that the vowel violation produced a positive effect only when the tone was correct. This indicates that vowel and tone processing interacts in the later processing stage, which involves both error detection and reanalysis of the spoken input. Implications of the present results for models of speech perception are discussed.
Computationally Efficient Estimation of Factor Multivariate Stochastic Volatility Models
Weijun Xu,Li Yang,Robert Kohn
Statistics , 2010,
Abstract: An MCMC simulation method based on a two stage delayed rejection Metropolis-Hastings algorithm is proposed to estimate a factor multivariate stochastic volatility model. The first stage uses kstep iteration towards the mode, with k small, and the second stage uses an adaptive random walk proposal density. The marginal likelihood approach of Chib (1995) is used to choose the number of factors, with the posterior density ordinates approximated by Gaussian copula. Simulation and real data applications suggest that the proposed simulation method is computationally much more efficient than the approach of Chib. Nardari and Shephard (2006}. This increase in computational efficiency is particularly important in calculating marginal likelihoods because it is necessary to carry out the simulation a number of times to estimate the posterior ordinates for a given marginal likelihood. In addition to the MCMC method, the paper also proposes a fast approximate EM method to estimate the factor multivariate stochastic volatility model. The estimates from the approximate EM method are of interest in their own right, but are especially useful as initial inputs to MCMC methods, making them more efficient computationally. The methodology is illustrated using simulated and real examples.
SNPs and TFBS Associated with High Altitude Sickness*  [PDF]
Norman E. Buroker, Xuehan Ning, Zhaonian Zhou, Kui Li, Weijun Cen, Xiufeng Wu, Weizhong Zhu, C. Ronald Scott, Shihan Chen
Open Journal of Blood Diseases (OJBD) , 2013, DOI: 10.4236/ojbd.2013.33018
Abstract: The rSNPs for the genes AKT3 (rs4590656), EGLN1 (rs480902), eNOS3 (rs1007311), and VEGFA (rs699947, rs13207311, rs1570360, rs2010963) have been significantly associated with the physiological parameters in high altitude sickness Han or Tibetan Chinese patients at the Qinghai-Tibetan plateau. The alleles of each rSNP have been found to create unique transcriptional factor binding sites for transcription factors that affect the process of hypoxia gene expression in this high altitude hypoxia environment.
Relative Widths of Some Sets of lmp  [PDF]
Weiwei Xiao, Weijun Luan
Advances in Pure Mathematics (APM) , 2011, DOI: 10.4236/apm.2011.12008
Abstract: n this paper, the relative widths of some sets in are studied. Relative widths is the further development of Kolmogorov widths and it is a new problem in approximation theory which aroused some mathematics workers great interest recently. We present some basic propositions of relative widths and investigate relative widths of some sets (ball or ellipsoid) of
Present Assessment of Public Traffic System Based on GIS in Kitakyushu  [PDF]
Kazuyuki Watari, Weijun Gao
Open Journal of Civil Engineering (OJCE) , 2014, DOI: 10.4236/ojce.2014.44034
Abstract: With increasing of serious environment problems and the coming of the aging society, new traffic systems should be urgently rebuilt. It is necessary to evaluate the traffic service level by utilizing new technique and tool. This paper takes Kitakyushu city as case study to carry out an evaluation of urban traffic system. The concept of accessibility and mobility is used to evaluate the present condition of existing public traffic system based on GIS technology, and then establishment of new route is discussed according to the evaluation results. Additionally, this paper established GIS database and illustrated the relationship between the public traffic and population density. The regions without enough existing traffic were identified. Moreover, the essential terms and considerations were put forward to simulate a new route of public traffic line.
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