一种独立任务调度问题的相对量化模型

在分布式处理领域,独立任务调度问题是一个NP难题.现有各种调度模型普遍采用基于运行时间的任务量化方式,这使得异构系统调度问题较同构系统更为复杂,因为异构系统中同一任务在不同节点上的运行时间不等.该文提出了一种独立任务调度问题的相对量化模型,该模型采用一种相对量化方案来量化任务的载荷量和计算节点的负载能力及负载状况.基于该模型,可用LPT、AI之类的同构调度算法解决异构调度问题,从而使异构调度问题的复杂度降到与同构调度问题相当.理论分析与实验研究证明了新模型的有效性和良好的工程实用性.

基于小波变换和相对量化的图像数字水印算法

提出了一种基于分块小波变换和相对量化的图像数字水印算法。由于在算法中采用了量化嵌入策略,从而在提取水印时无需原始图像和原始水印。实验结果表明,该算法对嵌入的水印具有很好的透明性,对亮度和对比度调整攻击具有非常强的稳健性,对JPEG压缩、重采样、颜色抖动、平滑和加噪声等常见的图像处理攻击具有很强的稳健性,并且算法思想简单、步骤简便和容易实现。

关于A/D转换器量化误差与“量化相对误差”的讨论

A/D转换器在转换模拟信号为数字信号时 ,量化误差对大小模拟信号影响不同 ,对小信号转换精度造成的误差较大。为提高小信号的转换精度 ,本文提出量化相对误差问题 ,并给出一种误差平衡法 ,使A/D转换器转换小信号误差较大的问题得以改善。

基于量化相对约简格的关联规则发现

关联规则发现是KDD中的一个重要的问题,而量化相对约简格作为一种新的表示数据和知识的有效工具,对于概念格结构进行了更为有效的缩减,非常适于数据库中的知识发现.文章对基于量化相对约简格进行关联规则的快速发现进行了讨论,提出了基于频繁概念子格进行规则提取的方法,并进行了相应的理论研究.

汽车轻量化评价方法研究

汽车整车轻量化水平与油耗大小密切相关,目前还没有公认的评价措施。本文研究大量车型数据,得出3种轻量化评价方法:针对同类车型,以4门轿车和承载式SUV(运动型多用途轿车)为例,整车面密度(L0=Wk/A,Wk为整备质量,A为轮边距与轴距乘积所得投影面积)随A近似线性增加;为量化表征,推导出整车相对面密度ΔLm=L0–La=Wk/A–a·A–b;划分为7级轻量化评价等级;对不同种类乘用车,考虑乘客人数的概率,提出人均轻量化系数Lp的方法;提出零部件相对轻量化系数Lr的评价方法,以前横梁总成为例验证了评价方法的有效性。

蔬菜发酵过程中亚硝酸盐对细菌群落积累量的影响

高通量测序(HTS)技术极大地促进了对发酵食品中微生物群落结构变化的相关研究,但是对相对丰度的分析忽略了不同样本之间细菌群落积累量存在的现实差异。该研究设计自然发酵体系(S)与添加亚硝酸盐发酵体系(Y),利用16S rRNA高通量测序技术对发酵过程中微生物群落结构变化进行研究,同时通过将相对丰度与OD_(600 nm)值结合的方法对发酵过程中微生物群落积累量进行量化,只修正分析相对丰度带来的偏差,进而更好地分析蔬菜发酵过程中菌群结构的动态变化。研究结果表明,相对丰度的降低并不能代表其微生物积累量的减少;当相对丰度值没有明显波动时不能表示其菌微生物的积累量也没有波动;相对丰度上升或下降的比例也不能完全说明该菌的积累量也呈现相同比例的增加或减少。该研究中对相对丰度的量化方法还未见报道,对未来利用相对丰度对细菌群落结构研究的方法具有借鉴意义,同时进一步强调在利用高通量测序对微生物群落结构变化进行分析时,不能仅仅考虑微生物的相对丰度,应该同时考虑微生物的总量。

天津滨海新区生态系统服务评估及空间分级

采用提出的"功能当量"相对评估模型,并以RS和GIS为技术平台对2009年天津滨海新区生态系统服务功能进行评估,采用区域网格化空间表达,对研究区进行分级研究.结果表明,滨海新区生态系统单位面积服务功能当量大小依次为湿地、水体、林地、草地、耕地、裸地;2009年滨海新区生态系统服务功能当量总和为1068680.13,III级以上功能当量的单元格比例为71.22%,总体处于较高水平;通过与价值量法结果对比,得出利用"功能当量"相对评估模型对研究区的评估结果与价值量法的评估结果具有显著相关性,证明该评估模型的可行性和合理性.

基于威胁分析的信息系统风险评估方法

对信息系统风险评估的方法有多种,该文提出了基于威胁分析的量化风险评估方法。包括其评估的步骤、量化的不同实现方式——绝对量化方式和相对量化方式、两种量化方式的优缺点分析以及两种量化方式评估的举例说明。

基于实时电价预测的智能家居器具优化调度

针对家庭器具优化调度中电价预测误差高和用户舒适度衡量偏差大的问题,提出了一种基于小波、微粒子群和自适应神经网络模糊推理系统(Wavelet-PSO-ANFIS,WPA)电价预测的家庭器具优化调度算法。并在该算法中针对器具运行时长不同的问题,提出了一种新颖的相对量化舒适度的方法。仿真结果表明,此电价预测方法在不牺牲计算复杂度的基础上提高了预测精度,不仅可以权衡用户的用户支付和不满意度,还可以降低系统的峰均比。

基于Hilbert变换的结构非线性判断方法

研究了运用Hilbert变换判断系统非线性状态的方法在地震工程中的应用。介绍了运用Hilbert变换判断系统非线性状态的基本理论和非线性程度相对量化指标,在考虑测量噪声影响的情况下,对一个具有Bouc-Wen模型的单自由度非线性结构进行了数值仿真分析。结果表明,随着地震波峰值的增大,结构频率响应函数幅值曲线与相应的Hilbert变换幅值曲线的差异在增大,结构的非线性程度相对量化指标也在增大,说明运用Hilbert变换和非线性程度相对量化指标可以有效地判断结构的非线性状态,为结构的振动控制和健康监测提供一定的参考价值。

Effects of Relative Soil Water Content on Antioxidant Enzyme System in Malus sieversii(Lebed.) Roem

By pot experiment under artificially simulated water stress conditions, soluble protein content, MDA content and SOD, POD, CAT and APX activities in Malus sieversfi leaves were determined to reveal the response mechanism of M. sieversii to changes of relative soil water content. According to the results, with the decrease of relative soil water content, MDA content in M. sieversii leaves increased by mem- brane lipid peroxidation. Cells resist water stress-induced membrane lipid peroxidation and clear the increased reactive oxygen species by improving soluble protein content and SOD, POD, CAT and APX activities. However, various enzymes were involved in the response to water stress under different moisture conditions. In addition, the results indicated that M. sieversii had a good adaptability to higher relative soil water contents.

Energies and Transition Rates of Low-Lying Excited States for Beryllium

Low lying excited states of beryllium are calculated with multiconfiguration interaction method. The relativisitic corrections and mass polarization are included. The oscillator strength and radiation rates are also calculated. Our results are in good agreement with other theoretical data.

Evolution of distribution and content of water in cement paste by low field nuclear magnetic resonance

The low field nuclear magnetic resonance (NMR), as a nondestructive and noninvasive technique, was employed to investigate the water distribution and content in cement paste with different water-to-cement ratio (w/c ratio) during early and later hydration stages. From the water distribution spectrum deduced from relaxation time distribution in paste, it is suggested that the water fills in the capillary pores at initial period, and then diffuses to the mesopores and gel pores in hydration products with the hydration proceeding. The decrease of peak area in water distribution spectrum reflects the transformation from physically bound water to chemically bound water. In addition, based on the connection between relaxation time and pore size, the relative content changes of water in various states and constrained in different types of pores were also measured. The results demonstrate that it is influenced by the formation of pore system and the original water-to-cement ratio in the paste. Consequently, the relative content of capillary water is dropped to less than 2% in the paste with low w/c ratio of 0.3 when being hydrated for 1 d, while the contents are still 16% and 36% in the pastes with w/c ratios of 0.4 and 0.5, respectively.

Effect of the Interference Instant of Zeolite HY Catalyst on the Pyrolysis of Pubescens

A laboratory reactor was designed to test the effect of the interference instant of HY on the pyrolysis of pubescens.The time instant for intermediate species from pyrolysis to contact HY was controlled by varying the position of the catalyst bed relative to the pyrolytic cell.It was found that the effect of the interference instant was significant on the variation of different intermediate species,and the yield and quality of the products.The results also showed that,with the increase in the distance between the pyrolytic cell and the catalyst bed,the yield of liquid and relative content of the organics such as aldehyde,phenols,etc.,decreased,while the yield of residue and relative content of acetic acid increased.The deoxygenation of the intermediate species was favored when the catalyst exerted its performance on them immediately after their formation.

Structure and Anti-influenza A(H1N1) Virus Activity of Three Polysaccharides from Eucheuma denticulatum

Three polysaccharides （EW, EH and EA） were prepared from a red alga Eucheuma denticulatum by sequential extraction with cold water, hot water and sodium hydroxide water solution. Their monosaccharide compositions, relative molecular mass and structural characterization were determined by gas chromatography, high performance liquid chromatography, fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy methods. EW was hybrid l/k/v-carrageenan （701/17k/13v-car- rabiose）, EH was mainly t-carrageenan, and EA was mainly α-1,4-Glucan （88%） but mixed with small amount of t-carrageenan （12%）. The relative molecular mass ofEW, EH and EA was 480, 580 and 510kDa, respectively. The anti-influenza A （H1N1） virus activity of these three polysaccharides was evaluated using the Madin-Darby canine kidney cells model. EW showed good anti-H1N1 virus activity, its ICso was 276.5 μg mL-1, and the inhibition rate to H1N1 virus was 52% when its concentration was 250 μgmL-1. The ICs0 of t-carrageenan EH was 366.4 μgmL1, whereas EA showed lower anti-H1N1 virus activity （IC50〉430μgmL-1）. Available data obtained give positive evidence that the hybrid carrageenan EW from Eueheuma denticulatum can be used as potential anti-H1N1 virus inhibitor in future.

Catalytic synthesis of perfluorolyethers

Perfluorolyether is characterized by highly chemical inertness, oxidative stability, anticorrosion as well as radiation resistance. It can be used as lubricant especially in harsh environmental conditions. In this work, hexafluoropylene oxide was catalytically polymerized at low temperature using the methods of anionic polymerization, and perfluorolyethers were obtained with number-average degree of polymerization more than 15. CsF and RbF were used as catalysts and their catalytic activities were investigated. Experimental results show that perfluorolyethers with number-average molar masses up to 3 000 g/mol could be obtained using the two kinds of catalysts, respectively. As compared to CsF, the number-average degree of polymerization is higher and the relative molecular mass distribution interval is narrower when RbF is used as catalyst. The effect of factors such as impurities＇ content, reaction temperature and reaction time on the number-average degree of polymerization was also investigated. It is found that low impurities＇ content and low temperature are beneficial to the generation of high number-average degree of perfluorolyethers. The optimization reaction time is 24 h, and fiarther increase of reaction time does not significantly affect the average relative molecular mass. The product was characterized by IR, 19F NMR and GC-MS, and the catalytic mechanism was analyzed finally.

Relativistic Center-of-Mass Vector and Electric Polarizability of a Charged PionMeson

Comparing the relativistic and nonrelativistic frame works, we study the effect of the relativistic center-of-mass vector on the electric polarizability of a compound system.

Correction of Relativistic Center-of-Mass Vector on Electric Polarizability of Pion Meson

We estimate the correction of relativistic center-of-mass vector on electric polarizability of an equal-mass quark-antiquark system numerically. Effect on the system confined by different interactive potentials is analysed. A great improvement for the electric polarizability of pion meson is obtained.

Physiological and Biochemical Changes Induced by PRD Irrigation in Four Olive Varieties

The present study was conducted to evaluate the effects of partial root-zone drying （PRD） irrigation technique on stomatal conductance （gs）, leaf water potential （qJpd）, leaf relative water content （RWC）, vegetative growth, fruit quality and enzymatic antioxidants of young plants of four Olea europaea L. varieties （Picholine Marocaine, Haouzia, Picholine Languedoc and Manzanilla） grown under arid conditions in Southern Morocco. In this irrigation strategy, a split-root technique was used to divide the root system of the plants in two parts. Two water regimes were used： （1） control, with both root compartments well watered; （2） PRD, with one compartment irrigated （50% of the control）, the other compartment was kept dry switching every 10 days. For all olive varieties studied, gs and the shoot length of the plants subjected to PRD decreased, whereas, Woo and RWC remained higher. The effect of PRD was similar among the four olive varieties, with their stomata closing in response to the water deficit before any significant changes in leaf water status were detectable. At the agronomic level, the benefits of PRD on olive were expressed by an earlier maturity and by higher values of olive fruit weight and dimensions, especially, in Manzanilla, which produced a fruit reaching 7.1 g and 2.6 cm, respectively. The enzymatic activities of soluble peroxidases （POX）, insoluble peroxidases （POXins）, polyphenoloxidase （PPO） and superoxide dismutase （SOD） were up-regulated under PRD. Picholine Marocaine and Haouzia showed higher enzymatic activities revealing that in these two varieties, PRD had possibly induced oxidative stress, which resulted in an up-regulation of the antioxidant activities of POXins, POX, PPO and SOD under water deficit.

Solubility of red palm oil in supercritical carbon dioxide： Measurement and modelling

The solubility of red palm oil （RPO） in supercritical carbon dioxide （scCO2） was determined using a dynamic method at 8.5-25 MPa and, 313.15-333.15 K and at a fixed scCO2 flow rate of 2.9 g. mn -1 using a full factorial design. The solubility was determined under low pressures and temperatures as a preliminary study for RPO par- ticle formation using scCO2. The solubility of RPO was 0.5-11.3 mg. （g CO2） -1 and was significantly affected by the pressure and temperature. RPO solubility increased with pressure and decreased with temperature. The Adachi-Lu model showed the best-fit for RPO solubility data with an average relative deviation of 14% with a high coefficient of determination, R2 of 0.9667, whereas the Peng-Robinson equation of state thermodynamic model recorded deviations of 17%-30%.