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Search Results: 1 - 10 of 78431 matches for " Zhixiang Chen "
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Investigation of supplier/buyer coordination performance in chinese companies
Zhixiang, Chen;
Gest?o & Produ??o , 2004, DOI: 10.1590/S0104-530X2004000300004
Abstract: this paper discusses the performance of supplier/buyer coordination in supply chain systems in china based on data from a survey of that country's business sector. the survey indicates that the rapidly expanding economy has raised the awareness of an increasing number of chinese firms to the importance of cooperating and coordinating with partners in supply chain management. however, although coordinated delivery, quality and responsiveness show an upward trend, such is not the case in information sharing and in cooperative efforts to reduce inventory and costs. hence, many companies have yet to form close cooperative relationships with partners. this study may be useful for both chinese and foreign companies, serving to underpin the development of new strategies for operating supply chains in the changing global economy.
Faster Deterministic Algorithms for Packing, Matching and $t$-Dominating Set Problems
Shenshi Chen,Zhixiang Chen
Computer Science , 2013,
Abstract: In this paper, we devise three deterministic algorithms for solving the $m$-set $k$-packing, $m$-dimensional $k$-matching, and $t$-dominating set problems in time $O^*(5.44^{mk})$, $O^*(5.44^{(m-1)k})$ and $O^*(5.44^{t})$, respectively. Although recently there has been remarkable progress on randomized solutions to those problems, our bounds make good improvements on the best known bounds for deterministic solutions to those problems.
Apply AcryditeTM Gel Separation to Solve Time-Table Problem
Zhixiang Yin,Min Chen
TELKOMNIKA : Indonesian Journal of Electrical Engineering , 2012, DOI: 10.11591/telkomnika.v10i5.1271
Abstract: Time-table problem is a classical NP-complete problem. Algorithm of DNA computing for time-table problem was obtained with introducing the technology of AcryditeTM gel separation. Each class period viewed as a graph vertex was mapped into DNA molecules chain. With the probe coding, the gel column was constructed to arrange the order of DNA chain through biological reaction. The problem was solved by gel column that performs the basic core processing and extraction that makes the result visible. The minimum number of cycles of arrangement was the minimum number of class hours. The simulation results show that the algorithm compared with others is very easy and feasible.
The Complexity of Testing Monomials in Multivariate Polynomials
Zhixiang Chen,Bin Fu
Computer Science , 2010,
Abstract: The work in this paper is to initiate a theory of testing monomials in multivariate polynomials. The central question is to ask whether a polynomial represented by certain economically compact structure has a multilinear monomial in its sum-product expansion. The complexity aspects of this problem and its variants are investigated with two folds of objectives. One is to understand how this problem relates to critical problems in complexity, and if so to what extent. The other is to exploit possibilities of applying algebraic properties of polynomials to the study of those problems. A series of results about $\Pi\Sigma\Pi$ and $\Pi\Sigma$ polynomials are obtained in this paper, laying a basis for further study along this line.
Approximating Multilinear Monomial Coefficients and Maximum Multilinear Monomials in Multivariate Polynomials
Zhixiang Chen,Bin Fu
Computer Science , 2010, DOI: 10.1007/978-3-642-17458-2_26
Abstract: This paper is our third step towards developing a theory of testing monomials in multivariate polynomials and concentrates on two problems: (1) How to compute the coefficients of multilinear monomials; and (2) how to find a maximum multilinear monomial when the input is a $\Pi\Sigma\Pi$ polynomial. We first prove that the first problem is \#P-hard and then devise a $O^*(3^ns(n))$ upper bound for this problem for any polynomial represented by an arithmetic circuit of size $s(n)$. Later, this upper bound is improved to $O^*(2^n)$ for $\Pi\Sigma\Pi$ polynomials. We then design fully polynomial-time randomized approximation schemes for this problem for $\Pi\Sigma$ polynomials. On the negative side, we prove that, even for $\Pi\Sigma\Pi$ polynomials with terms of degree $\le 2$, the first problem cannot be approximated at all for any approximation factor $\ge 1$, nor {\em "weakly approximated"} in a much relaxed setting, unless P=NP. For the second problem, we first give a polynomial time $\lambda$-approximation algorithm for $\Pi\Sigma\Pi$ polynomials with terms of degrees no more a constant $\lambda \ge 2$. On the inapproximability side, we give a $n^{(1-\epsilon)/2}$ lower bound, for any $\epsilon >0,$ on the approximation factor for $\Pi\Sigma\Pi$ polynomials. When terms in these polynomials are constrained to degrees $\le 2$, we prove a $1.0476$ lower bound, assuming $P\not=NP$; and a higher $1.0604$ lower bound, assuming the Unique Games Conjecture.
Research of Uncertainty Problem of Production Planning Information under Supply Chain Environment
SCM环境中生产计划信息不确定性问题研究

Chen ZhiXiang,
陈志祥

计算机系统应用 , 2005,
Abstract: 本文探讨在供应链环境下ERP生产计划信息不确定性产生的原因及对生产计划的影响;从数据模式转化机制与数据库集成机制两方面探讨了供应链环境下生产计划信息集成机制问题,并建立了基于数据传递、数据共享、应用集成三个层次的信息共享机制。
Differential Regulation of Transcription Factors by Location-Specific EGF Receptor Signaling via a Spatio-Temporal Interplay of ERK Activation
Peng Wu,Ping Wee,Jennifer Jiang,Xinmei Chen,Zhixiang Wang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0041354
Abstract: It is well established that EGFR signals from both the plasma membrane (PM) and endosome (EN). However, very little is known about whether and how the EGFR signals at the PM and EN to differentially regulate various signaling pathways and the physiological outcomes. In this communication, we established a system that allowed the specific activations of EGFR at different cell locations: PM and EN. PM activation of EGFR is achieved by activation of endocytosis-deficient mutant EGFR1010LL/AA stably expressed in CHO cells (CHO-LL/AA cell). EN activation of EGFR is achieved by activating the wild type EGFR stably expressed in CHO cells (CHO-EGFR cell) after its internalization into EN with a previously reported protocol. We showed that both EGFR activations at PM and EN activated ERK to a similar level, but differentially stimulated transcriptional factors c-jun and c-fos. We further showed that EGFR activations at PM and EN resulted in differential spatio-temporal dynamics of phosphorylated ERK which caused the differential activation of two downstream substrates ELK1 and RSK. Finally we showed that EGFR signaling from PM and EN led to different physiological outcomes. CHO-LL/AA cells that only generate PM EGFR signals have a larger cell size and slower proliferation rate than CHO-EGFR cells. We conclude that location-specific EGFR activation differentially regulates cell functions through a spatio-temporal interplay of ERK activation.
Roles of Arabidopsis WRKY3 and WRKY4 Transcription Factors in Plant Responses to Pathogens
Zhibing Lai, KM Vinod, Zuyu Zheng, Baofang Fan, Zhixiang Chen
BMC Plant Biology , 2008, DOI: 10.1186/1471-2229-8-68
Abstract: Both WRKY3 and WRKY4 are nuclear-localized and specifically recognize the TTGACC W-box sequences in vitro. Expression of WRKY3 and WRKY4 was induced rapidly by stress conditions generated by liquid infiltration or spraying. Stress-induced expression of WRKY4 was further elevated by pathogen infection and SA treatment. To determine directly their role in plant disease resistance, we have isolated T-DNA insertion mutants and generated transgenic overexpression lines for WRKY3 and WRKY4. Both the loss-of-function mutants and transgenic overexpression lines were examined for responses to the biotrophic bacterial pathogen Pseudomonas syringae and the necrotrophic fungal pathogen Botrytis cinerea. The wrky3 and wrky4 single and double mutants exhibited more severe disease symptoms and support higher fungal growth than wild-type plants after Botrytis infection. Although disruption of WRKY3 and WRKY4 did not have a major effect on plant response to P. syringae, overexpression of WRKY4 greatly enhanced plant susceptibility to the bacterial pathogen and suppressed pathogen-induced PR1 gene expression.The nuclear localization and sequence-specific DNA-binding activity support that WRKY3 and WRKY4 function as transcription factors. Functional analysis based on T-DNA insertion mutants and transgenic overexpression lines indicates that WRKY3 and WRKY4 have a positive role in plant resistance to necrotrophic pathogens and WRKY4 has a negative effect on plant resistance to biotrophic pathogens.Upon pathogen infection, pathogen-associated molecular patterns (PAMPs) such as bacterial flagellin and lipopolysaccharides are recognized by plant receptors to activate PAMP-triggered immunity through a mitogen-activated protein kinase signaling cascade [1]. Gram-negative bacterial pathogens such as Pseudomonas syringae can deliver effector proteins to plant cells to interfere PAMP-triggered resistance to promote pathogen virulence. As a result, the remaining basal defense is usually insuffi
Quantitative genetic analysis station for the genetic analysis of complex traits
GuoBo Chen,ZhiXiang Zhu,FuTao Zhang,Jun Zhu
Chinese Science Bulletin , 2012, DOI: 10.1007/s11434-012-5108-0
Abstract: The Quantitative Genetic Analysis Station (QGAStation) is a software package that has been developed to perform statistical analysis for complex traits. It consists of five domains for handling data from diallel crosses, regional trials, core germplasm collections, QTL mapping, and microarray experiments. The first domain contains genetic models for diallel cross analysis, in which genetic variance components and genetic-by-environment interactions can be estimated, and genetic effects can be predicted. The second domain evaluates the performance of varieties in regional trials by implementing a general statistical method that outperforms ANOVA in tackling unbalanced data that arises frequently in trials across multiple locations and over a number of years. The third domain, using predicted genotypic values as proxy, constructs core germplasm collections covering sufficient genetic diversity with lower redundancy. The fourth domain manages genotypic and phenotypic data for QTL mapping. Linkage maps can be constructed and genetic distances can be estimated; the statistical methods that have been implemented apply to both chiasmatic and achiasmatic organisms. Another part of this domain can filter systematic noises in phenotypic data. The fifth domain focuses on the cDNA expression data that is generated by microarray experiments. A two-step strategy has been implemented to detect differentially expressed genes and to estimate their effects. Except in the fourth domain, the major statistical methods that have been used are mixed linear model approaches that have been implemented in the C language. Computational efficiency is further boosted for computers that are equipped with graphics processing units (GPUs). A user friendly graphic interface is provided for Microsoft Windows and Apple Mac operating systems. QGAStation is available at http://ibi.zju.edu.cn/software/qga/.
Performance and mechanism study for low:temperature SCR of NO with propylene in excess oxygen over Pt/TiO2 catalyst

Zhixiang Zhang,Mingxia Chen,Zhi Jiang,Wenfeng Shangguan,

环境科学学报(英文版) , 2010,
Abstract: A 0.5 wt.% Pt/TiO2 catalyst was prepared and used for the low-temperature selective catalytic reduction (SCR) of NO with C3H6 in the presence of excess oxygen. The e ects of Pt loading and O2 concentration on Pt/TiO2 catalytic performance for low-temperature SCR were investigated. It was found that optimal Pt loading was 0.5 wt.% and excess O2 favored low-temperature SCR of NOx. The mechanism of low-temperature SCR of NO with C3H6 was investigated with respect to the behavior of adsorbed species over Pt/TiO2 at 150°C using in situ DRIFTS. The results indicated that surface nitrosyl species (Pt +-NO and Ti3+-NO) and Pt2+-CO are main reaction intermediates during the interactions of NO, C3H6 and O2. A simplified NO decomposition mechanism for the low-temperature SCR of NO with C3H6 was proposed.
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