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Search Results: 1 - 10 of 28951 matches for " Xiaoyan Ma "
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An Approach to Dynamic Asymptotic Estimation for Hurst Index of Network Traffic  [PDF]
Xiaoyan MA, Hongguang LI
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2010, DOI: 10.4236/ijcns.2010.32023
Abstract: As an important parameter to describe the sudden nature of network traffic, Hurst index typically conducts behaviors of both self-similarity and long-range dependence. With the evolution of network traffic over time, more and more data are generated. Hurst index estimation value changes with it, which is strictly consistent with the asymptotic property of long-range dependence. This paper presents an approach towards dynamic asymptotic estimation for Hurst index. Based on the calculations in terms of the incremental part of time series, the algorithm enjoys a considerable reduction in computational complexity. Moreover, the local sudden nature of network traffic can be readily captured by a series of real-time Hurst index estimation values dynamically. The effectiveness and tractability of the proposed approach are demonstrated through the traffic data from OPNET simulations as well as real network, respectively.
The Skills of Teacher’s Questioning in English Classes
Xiaoyan Ma
International Education Studies , 2008, DOI: 10.5539/ies.v1n4p92
Abstract: English is a main subject in Chinese English classes, which requires plenty of practice, needs cooperation between the teacher and students in class to jointly fulfill the verbal communication and the teaching-learning procedure. Classroom questioning, the skill of the elicitation method of teaching that is student-oriented and advocated today, gives an incentive to communicative activities in English. Raising questions effectively is a major method of the teacher who guides his students to think actively, fostering students’ ability of analysis and creation. It is also an essential way for the teacher to output information and obtain feedback, and an important channel to exchange ideas between the teacher and students. Therefore, the teacher must pay great attention to the skill of asking questions in English class. Each question must be presented to accomplish the teaching objective and task. Only in this way may the English teachers ask question effectively and improve the skill of questioning so as to make contribution to our Chinese English education. To begin with some elemental definitions, this paper discusses some basic knowledge of questions, and then explores the skill of questioning in English class about the preparing, designing, controlling and evaluating of questioning. Finally the benefit of the skill is studied with abundant teaching cases. The paper analyzes tentative in English class by integrating theory with practice. Thus, the skills of questioning are further understood in English classes.
A Novel Parameter Tuning Algorithm for AQM-PI Controllers
Ma XiaoYan,Li HongGuangr
Research Journal of Applied Sciences, Engineering and Technology , 2012,
Abstract: AQM is recognized as an active queue management mechanism to solve network congestion. As an easily implemented algorithm, PI controllers can effectively control the queue length of router. Based on indepth analysis of classical design methodologies towards PI controllers, this paper explicitly introduces a novel PI parameter tuning algorithm, which takes advantage of the relationship between PI parameters and control systems’ damping ratios and employs recursive bisection searching approaches to achieve an optimum damping ratio in terms of both steady-state and accuracy; performances of controlled queue length, thereby obtaining the best parameters of PI controllers. An experimental study is carried out to demonstrate the effectiveness of the proposed algorithm.
Prediction of Coal Bed Methane Recovery Rate and Its Improvement Measures in Dafosi Mine Field  [PDF]
Dongmin Ma, Chenyang Zhang, Chuantao Wang, Xiaoyan Tang
Journal of Power and Energy Engineering (JPEE) , 2017, DOI: 10.4236/jpee.2017.511004
Abstract: The recovery rate of coalbed methane (CBM) can reflect the mining situation and the residual gas in coal reservoir. It plays an important role in the calculation of the recoverable resources. This paper mainly uses isothermal adsorption curve method and hydraulic model method to predict recovery rate of CBM. The isothermal adsorption curve method considering desorption lag problem in the prediction process, which is more in line with the actual situation. In the hydraulic model method, the recovery rate of “V” type well is the largest in the early stage. But with the time going on, the recovery rate of multilateral horizontal well is greater than vertical well, “U” type well and “V” type well finally. The factors affecting CBM recovery rate include geological characteristics, development conditions and economic factors. The geological characteristics of coal reservoir are the main factors affecting CBM recovery rate, and corresponding measures can be adopted to improve the recovery rate.
Plasma and cavitation dynamics during pulsed laser microsurgery in vivo
M. Shane Hutson,Xiaoyan Ma
Physics , 2007, DOI: 10.1103/PhysRevLett.99.158104
Abstract: We compare the plasma and cavitation dynamics underlying pulsed laser microsurgery in water and in fruit fly embryos (in vivo) - specifically for nanosecond pulses at 355 and 532 nm. We find two key differences. First, the plasma-formation thresholds are lower in vivo - especially at 355 nm - due to the presence of endogenous chromophores that serve as additional sources for plasma seed electrons. Second, the biological matrix constrains the growth of laser-induced cavitation bubbles. Both effects reduce the disrupted region in vivo when compared to extrapolations from measurements in water.
Construction and primary analysis of human keratinocyte model expressing anti-sense protein kinase Cζ
Xiaoyan Zhang,Huitu Liu,Shengqing Ma
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02883448
Abstract: Protein kinase C (PKC), which has a wide variety of functions, comprises at least twelve isoenzymes that have distinct roles respectively. Research in recent years indicates that PKCζ plays a pivotal role in the regulation of cell proliferation. In order to investigate its role in the regulation of keratinocyte proliferation, eukaryotic expression plasmid of anti-sense PKCζ is constructed and transfected into human keratinocyte line, Colo16. The human keratinocyte model expressing anti-sense PKCζ is established successfully, the growth properties of the cell model is analyzed by the detection of cell growth curve and cell cycle phase. The mechanism of the relationship between PKCζ and CyclinD1 is also investigated by the western blotting analysis of CyclinDl protein.
Obesity does not aggravate vitrification injury in mouse embryos: a prospective study
Ma Wenhong,Yang Xing,Liang Xiaoyan
Reproductive Biology and Endocrinology , 2012, DOI: 10.1186/1477-7827-10-68
Abstract: Background Obesity is associated with poor reproductive outcomes, but few reports have examined thawed embryo transfer in obese women. Many studies have shown that increased lipid accumulation aggravates vitrification injury in porcine and bovine embryos, but oocytes of these species have high lipid contents (63 ng and 161 ng, respectively). Almost nothing is known about lipids in human oocytes except that these cells are anecdotally known to be relatively lipid poor. In this regard, human oocytes are considered to be similar to those of the mouse, which contain approximately 4 ng total lipids/oocyte. To date, no available data show the impact of obesity on vitrification in mouse embryos. The aim of this study was to establish a murine model of maternal diet-induced obesity and to characterize the effect of obesity on vitrification by investigating the survival rate and embryo developmental competence after thawing. Methods Prospective comparisons were performed between six–eight-cell embryos from obese and normal-weight mice and between fresh and vitrified embryos. Female C57BL/6 mice were fed standard rodent chow (normal-weight group) or a high-fat diet (obese group) for 6 weeks. The mice were mated, zygotes were collected from oviducts and cultured for 3 days, and six–eight-cell embryos were then selected to assess lipid content in fresh embryos and to evaluate differences in apoptosis, survival, and development rates in response to vitrification. Results In fresh embryos from obese mice, the lipid content (0.044 vs 0.030, P<0.01) and apoptosis rate (15.1% vs.9.3%, P<0.05)were significantly higher, the survival rate (83.1% vs. 93.1%, P<0.01) on day 5 was significantly lower, and embryo development was notably delayed on days 3–5 compared with the normal-weight group. After vitrification, no significant difference was found between thawed embryos from obese and normal-weight mice in apoptosis, survival, and development rates on days 4 and 5. In both groups, pre- and post-vitrification embryo apoptosis, survival, and development rates were similar. Conclusions This study demonstrated that differences in survival and developmental rates between embryos from obese and normal-weight mice were eliminated after vitrification. Thus, maternal obesity does not aggravate vitrification injury, but obesity alone greatly impairs pre-implantation embryo survival and development.
Research and Application of Contingency Plan Based on Hospital Network and Information System Security
Xiaoyan Ma,Hao Zou,Yujuan Li
Computer and Information Science , 2011, DOI: 10.5539/cis.v4n6p105
Abstract: Network and information system play irreplaceable roles in hospital daily administration. The system is so huge that any fault during its operation will cause serious consequences to hospital administration and bring immeasurable loss to the hospital; therefore, to set up corresponding contingency plans becomes increasingly important. From the perspective of management, the article puts forward contingency plans in terms of following three aspects: hospital network system, office automation and hospital information system.
Positive Solutions for the Initial Value Problems of Fractional Evolution Equation
Yue Liang,Yu Ma,Xiaoyan Gao
Journal of Function Spaces , 2013, DOI: 10.1155/2013/781404
Abstract: This paper discusses the existence of positive solutions for the initial value problem of fractional evolution equation with noncompact semigroup , ; in a Banach space , where denotes the Caputo fractional derivative of order , is a closed linear operator, generates an equicontinuous semigroup, and is continuous. In the case where satisfies a weaker measure of noncompactness condition and a weaker boundedness condition, the existence results of positive and saturated mild solutions are obtained. Particularly, an existence result without using measure of noncompactness condition is presented in ordered and weakly sequentially complete Banach spaces. These results are very convenient for application. As an example, we study the partial differential equation of parabolic type of fractional order. 1. Introduction The theory of fractional differential equations is a new and important branch of differential equation theory, which has an extensive physical background and realistic mathematical model; see [1–6]. Correspondingly, the existence of solutions to fractional evolution equations in Banach space has also been studied by several authors; see [7–17]. In [7, 8], El-Borai first constructed the type of mild solutions to fractional evolution equations in terms of a probability density. And then they investigated the existence, uniqueness, and regularity of solutions to fractional integrodifferential equations in [9, 10]. Recently, this theory was developed by Zhou et al. [11–14]. In [15–17], the authors studied the existence of mild solutions to fractional impulsive evolutions equations. But as far as we know, there are seldom results on the existence of positive solutions to the fractional evolution equations; see [18–20]. In this paper, we use the Sadovskii’s fixed point theorem and monotone iterative technique to discuss the existence of positive and saturated mild solutions for the initial value problem (IVP) of fractional evolution equations: in Banach space , where denotes the Caputo fractional derivative of order , is a closed linear operator, generates a -semigroup ( ) in , and is continuous and will be specified later, . In some existing articles, the fractional evolution equations were treated under the hypothesis that (I) generates a compact semigroup or (II) the nonlinearity is Lipschitz continuous in on a bounded set. For the case (I), the continuity of nonlinearity can guarantee the local existence of solutions. Hence it is convenient to apply to partial differential equations with compact resolvent. But for the case of noncompact semigroup,
Four SNPs in the CHRNA3/5 Alpha-Neuronal Nicotinic Acetylcholine Receptor Subunit Locus Are Associated with COPD Risk Based on Meta-Analyses
Kai Cui, Xiaoyan Ge, Honglin Ma
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0102324
Abstract: Background Several single nucleotide polymorphisms (SNPs) in an α-neuronal nicotinic acetylcholine receptor subunit (CHRNA3/5) were identified to be associated with chronic obstructive pulmonary disease (COPD) in a study based on a Norwegian population. However, results from subsequent studies have been controversial, particularly in studies recruiting Asians. In the present study, we conducted a comprehensive search and meta-analyses to identify susceptibility SNPs for COPD in the CHRNA3/5 locus. Methods A comprehensive literature search was conducted to find studies that have reported an association between SNPs in the CHRNA3/5 locus and COPD risk. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) for each SNP were calculated with the major allele or genotype as the reference group. The influence of individual studies on pooled measures was assessed, in addition to publication bias. Results A total of 12 articles with 14 eligible studies were included in this analysis. Association between 4 SNPs in the CHRNA3/5 locus and COPD was evaluated and included rs1051730, rs8034191, rs6495309, and rs16969968. Significant associations between the 4 SNPs and COPD were identified under allele (rs1051730: OR = 1.14, 95%CI = 1.10–1.18; rs8034191: OR = 1.29, 95%CI = 1.18–1.41; rs6495309: OR = 1.26, 95%CI = 1.09–1.45; rs16969968: OR = 1.27, 95%CI = 1.17–1.39) and genotype models. Subgroup analysis conducted for rs1051730 showed a significant association between this SNP and COPD risk in non-Asians (OR = 1.14, 95%CI = 1.10–1.18), but not Asians (OR = 1.23, 95%CI = 0.91–1.67). Rs1051730 and rs6495309 were also significantly associated with COPD after adjusting for multiple variables, including age and smoking status. Conclusion Our results indicate that 4 SNPs in the CHRNA3/5 locus are associated with COPD risk. Rs1051730 was particularly associated with COPD in non-Asians, but its role in Asians still needs to be verified. Additional studies will be necessary to assess the effect of rs6495309 on COPD. Although rs1051730 and rs6495309 were shown to be independent risk factors for COPD, validation studies should be performed.
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