基于MPA的单向偏心结构性态评估方法

为研究水平单向偏心结构的性态评估问题,在对偏心结构模态分析的基础上,建立了等效二自由度(EDDOF)简化模型,并用其计算包含平扭耦联效应的单向非对称结构地震反应.通过弹性反应分析,验证了EDDOF模型的正确性.将MPA方法用于单向偏心结构,提出了基于MPA的单向偏心结构性态评估方法.通过一个偏心钢框架结构算例验证了方法的正确性.结果表明:简化模型结合MPA方法,可以精确地描述单向非对称结构的弹性地震反应,对非弹性反应的计算精度也很好,且计算效率较高.

基于屈服点谱法的偏心支撑钢框架抗震性态评估

屈服点谱(Yield Point Spectra,YPS)是一种新的等延性位移-加速度反应谱,可用于结构的抗震性态设计及评估。给出了基于YPS的结构抗震性态评估方法,选取了两个按我国现行规范设计的偏心支撑钢框架算例,将由YPS法得出的结构顶部峰值位移、层间位移角与弹塑性时程分析的结果进行了对比,对比结果评价了YPS法用于偏心支撑钢框架性态评估的可信性。

有速度脉冲的近场地震下偏心支撑钢框架抗震性态评估

屈服点谱是一种新的位移-加速度反应谱,可用于结构抗震性态设计和性态分析。结构在近场地震动作用下的反应与远场地震作用明显不同,这是由近场地震动高能量的速度脉冲特征决定的。根据多条近场地震波构造了屈服点谱,对两个偏心支撑钢框架进行了强震下的性态评估。非线性时程分析结果验证了屈服点谱法用于近场地震评估的可信性。

基于贝叶斯框架下大坝服役性态综合评估方法

大坝服役性态的综合评估对水利枢纽的安全运行有重大意义。现有的评估模型存在过于依赖专家经验,缺乏客观性,或仅限于数据挖掘,未融入专业知识的不足。以贝叶斯网络为主要框架,提出了一种结合专家主观经验和客观实测数据的大坝性态评估方法。该方法根据朴素贝叶斯分类和BIC评分优化的方式确定网络结构,有效地厘清了影响因素之间的关系。利用模糊综合评价理论和熵权法分别求解先验分布和条件分布,运用贝叶斯估计进行推理,得到兼顾主观经验和客观数据的失效概率。结合失效概率等级表,对大坝服役性态进行有效的评估和定级。以某混凝土坝14个影响因素的时间序列为例,建立了该坝贝叶斯框架下多指标服役性态评估模型,并对其服役性态进行安全评级。最后从主观与客观、整体与部分、静态与动态3方面分析评估结果,证明了该方法的有效性。

基于等位移原理的二维能力谱方法

由于无法考虑地震动的多维性和结构的空间耦合特性,现有的结构性态评估方法多数无法用于偏心结构性态评估.在建立等效二自由度模型(EDDOF)的基础上,提出了基于等位移原理的二维能力谱方法,用弹性峰值反应近似计算结构的目标位移,采用模态Pushover分析(MPA)方法求出体系能力谱,并应用于EDDOF模型,进而得到结构性态反应.通过一个偏心钢框架结构算例验证了二维能力谱方法的正确性.结果表明:基于等位移原理的二维能力谱方法用于偏心结构的性态反应评估,具有计算精度可靠、求解效率高的特点.

平面偏心结构的三维能力谱方法

基于单自由度模型的性态评估方法,无法考虑偏心结构平扭耦联效应且不便于考虑双向地震动输入,存在很大的局限性。本文在对水平偏心结构模态分析的基础上,利用OpenSees构建等效三自由度模型(ETDOF),将该模型用于双向地震动作用下偏心结构平扭耦联简化计算和性态评估。在对ETDOF模型进行振动特性分析的基础上,基于等位移原理,简化了计算过程,提出了偏心结构双向地震动作用下的三维能力谱方法。通过一个偏心钢框架结构算例验证了三维能力谱法的正确性。结果表明,本文方法对求解平面偏心结构的非弹性性态反应具有精度可靠、求解效率高的特点。

Assessment of Ecotoxicity of Topsoils from a Wood Treatment Site

A series of 9 soil samples were taken at a timber treatment site in SW France where Cu sulphate and chromated copper arsenate （CCA） have been used as wood preservatives （Sites P1 to P9） and one soil sample was collected at an adjacent site on the same soil type （Site P10）. Copper was a major contaminant in all topsoils, varying from 65 （Soil P5） to 2600 mg Cu kg^-1 （Soil P7）, exceeding background values for French sandy soils. As and Cr did not accumulate in soil, except at Site P8 （52 mg As kg^-1 and 87 mg Cr kg^-1） where CCA-treated posts were stacked. Soil ecotoxicity was assessed with bioassays using radish, lettuce, slug Arion rufus L., and earthworm Dendrobaena octaedra （Savigny）. There were significantly differences in lettuce germination rate, lettuce leaf yield, radish root and leaf yields, slug herbivory, and earthworm avoidance. An additional bioassay showed higher negative impacts on bean shoot and root yields, Rhizobium nodule counts on Bean roots, and guaiacol peroxidase activity in primary Bean leaves for soil from Site PT, with and without fertilisation, than for soil from Site P10, despite both soils having a similar value for computed free ion Cu2＋ activity in the soil solution （pCu^2＋）. Beans grown in soil from Site P7 that had been fertilised showed elevated foliar Cu content and phytotoxic symptoms. Soils from Sites P7 （treatment plant） and P6 （storage of treated utility poles） had the highest ecotoxicity, whereas soil from Site P10 （high organic matter content and cation exchange capacity） had the lowest. Except at Site P10, the soil factor pCu^2＋ computed with soil pH and total soil Cu could be used to predict soil ecotoxicity.

POSTERIOR CRAMR-RAO BOUNDS ANALYSIS FOR PASSIVE TARGET TRACKING

For the problem of deterministic parameter estimate, the theoretical lower bound of esti- mate error is the Cramér-Rao bound; while for random parameter, the lower bound of estimate error is generally termed by Posterior Cramér-Rao Bound (PCRB). Under the background of passive tracking where the target's state can be seen as a time-varying random parameter, PCRB of the state estimate error is analyzed in this paper, and the relation between PCRB and varied condition is also fully in- vestigated using different simulation examples. The presented analytical method provides a theoretical base for performance assessment of all kinds of suboptimal estimate algorithms used in practice.

TP53 Arg72Pro polymorphism is associated with esophageal cancer risk:A meta-analysis

AIM:To investigate the association between TP53 Arg72Pro polymorphism and esophageal cancer(EC)risk using meta-analysis. METHODS:All eligible studies published before March 1,2010 were selected by searching PubMed using keywords"p53"or"TP53","polymorphism"or"variation", "esophageal"and"cancer"or"carcinoma".Crude odds ratios(ORs)with 95%confidence intervals(CIs)were assessed for EC risk associated with TP53 Arg72Pro polymorphism using fixed-and random-effects models. RESULTS:Nine case-control studies involving 5545 subjects were included in this meta-analysis.Significantly reduced risk of EC was associated with TP53genotypes for Arg/Arg+Arg/Pro vs Pro/Pro(OR= 0.73,95%CI:0.57-0.94,P=0.014).Subgroup analyses according to the source of controls and the specimens used for determining TP53 Arg72Pro genotypes or sample size showed that significantly reduced risk was observed only in studies which have populationbased controls(Arg/Arg vs Pro/Pro:OR=0.56,95% CI:0.47-0.66,P<0.001),and use white blood cells or normal tissue to assess TP53 genotypes of cases (Arg/Arg vs Pro/Pro:OR=0.56,95%CI:0.47-0.65,P <0.001)or include at least 200 subjects(Arg/Arg vs Pro/Pro:OR=0.56,95%CI:0.47-0.65,P<0.001). Analysis restricted to well-designed studies also supported the significantly decreased risk of EC(Arg/Arg vs Pro/Pro:OR=0.54,95%CI:0.46-0.64,P<0.001). CONCLUSION:TP53 Arg72 carriers are significantly associated with decreased EC risk.Nevertheless,more welldesigned studies are needed to confirm our findings.

Species Diversity and Population Status of Threatened Plants in Different Landscape Elements of the Rohtang Pass,Western Himalaya

This paper highlights the quantitative estimates of plant species diversity and ecosystems of the Rohtang Pass,which is one of the most preferred visiting spots by tourists in Himachal Pradesh (H.P.),India. In spite of high pressure of anthropogenic activities,the Rohtang Pass still harbours a variety of flowering plants with economic value,including various medicinal herbs. In order to observe species diversity in different landscape elements (LSEs),ground surveys were conducted in nine unique LSEs within the elevation range between 3624 m and 4332 m. Plant community structure in each LSE was studied using stratified random sampling where a total 56 quadrats of 1 m2 in size for herbs and 7 quadrats of 25 m2 for shrubs were made. Of the total 50 plant species belonging to 15 families recorded in different random quadrats,24 species were found of medicinal value. Maximum species richness (18) and value of Shannon diversity (H'=2.2648) were observed on northeast-facing slope in Picrorhiza kurrooa dominated LSE in moist area,followed by Rheum emodi LSE (species richness = 17 and H' = 2.4141) distributed on south-facing slope. Maximum values of species richness and Shannon diversity in Rheum emodi LSE were observed between 8 ～ 12 and 1.4797 ～ 2.1911,respectively. Rhododendron anthopogon dominated LSE on northwest-facing slope was found least diverse in terms of species richness where the Simpson index of dominance (D) was 0.4205. The species were equal in abundance in P. kurrooa LSE on east-facing slope and Pleurospermum candollii LSE on north-facing slope,showing the maximum similarity in terms of species distribution between the two LSEs. Low turnover of species across common LSEs gives an idea regarding their limited distribution. Five species of threatened category according to the IUCN criteria were observed in seven LSEs. The largest population of threatened medicinal plants was recorded on northeast and northwest-facing slopes where population density of Bergenia stracheyi (29.25 individuals/m2),Picrorhiza kurrooa (19.83 individuals/m2) and Rhododendron anthopogon (26.23 individuals/25m2) was highest. Aconitum heterophyllum was recorded for the lowest density (1 individual/m2). It was observed that the distribution of medicinal plants was very habitat-specific. Lower soil pH in most of the LSEs reflected its acidic nature. A significant positive correlation of Shannon diversity was found with soil organic matter,carbon content available and total nitrogen. Considering the continuous pressure of anthropogenic activities,this paper suggests effective ecotourism planning and plant conservation mechanisms to protect valuable plant bioresource at the Rohtang Pass.

Pseudo-Dynamic Testing for Seismic Performance Assessment of Buildings with Seismic Isolation System Using Scrap Tire Rubber Pad Isolators

Investigation of seismic performance of buildings with STRP （scrap tire rubber pad） seismic isolators by means of pseudo-dynamic tests and numerical simulation is presented. The isolated building is numerically modeled, while the base isolation layer is considered as the experimental substructure in the pseudo-dynamic tests. The test result verifies that the STRP isolator shows acceptable shear deformation performance predicted by the design methods, and demonstrated that seismic isolation using STRP works as a protective measure to provide enhanced seismic performance of the building indicated by the reduction of top floor absolute acceleration, drift and base shear as designated.

Comparison and Effects of Different Climate-Vegetation Models in Areas of Complex Terrain under Climate Change

Identifying the impacts of climate change is important for conservation of ecosystems under climate change, particularly in mountain regions. Holdridge life zone system and Koppen classification provide two effective methods to assess impacts of climate change on ecosystems, as typical climate-vegetation models. Meanwhile, these previous studies are insufficient to assess the complex terrain as well as there are some uncertainties in results while using the given methods. Analysis of the impacts of the prevailing climate conditions in an area on shifts of ecosystems may reduce uncertainties in projecting climate change. In this study, we used different models to depict changes in ecosystems at 1 km × 1 km resolution in Sichuan Province, China during 1961-2010. The results indicate that changes in climate data during the past 50 years were sufficient to cause shifts in the spatial distribution of ecosystems. The trend of shift was from low temperature ecosystems to high temperature ecosystems. Compared with K？ppen classification, the Holdridge system has better adaptation to assess the impacts of climate change on ecosystems in low elevation（0-1000 m）. Moreover, we found that changed areas in ecosystems were easily affected by climate change than unchanged areas by calculating current climate condition.

A Universal Fairness Evaluation Framework for Resource Allocation in Cloud Computing

In cloud computing,fairness is one of the most significant indicators to evaluate resource allocation algorithms,which reveals whether each user is allocated as much as that of all other users having the same bottleneck.However,how fair an allocation algorithm is remains an urgent issue.In this paper,we propose Dynamic Evaluation Framework for Fairness(DEFF),a framework to evaluate the fairness of an resource allocation algorithm.In our framework,two sub-models,Dynamic Demand Model(DDM) and Dynamic Node Model(DNM),are proposed to describe the dynamic characteristics of resource demand and the computing node number under cloud computing environment.Combining Fairness on Dominant Shares and the two sub-models above,we finally obtain DEFF.In our experiment,we adopt several typical resource allocation algorithms to prove the effectiveness on fairness evaluation by using the DEFF framework.

Rolling bearing performance degradation evaluation by VMD and embedding selection-based NPE

In order to improve the incipient fault sensitivity and stability of degradation index in the rolling bearing performance degradation evaluation process,an embedding selection-based neighborhood preserving embedding(ESNPE)method is proposed.Firstly,the acquired vibration signals are decomposed by variational mode decomposition(VMD),and the singular value and relative energy of each intrinsic mode function(IMF)are extracted to form a high-dimensional feature set.Then,the NPE manifold learning method is used to extract the embedded features in the feature space.Considering the problem that useful embedding information is easily suppressed in NPE,an embedding selection strategy is built based on the Spearman correlation coefficient.The effectiveness of embeddings is measured by the coefficient absolute value,and useful embeddings are preserved in the early stage of bearing degradation by using the first-order difference method.Finally,the degradation index is established using the support vector data description(SVDD)model and bearing performance degradation evaluation is achieved.The proposed method was tested with the whole life experiment data of a rolling bearing,and the result was compared with the feature extraction methods of traditional principal component analysis(PCA)and NPE.The results show that the proposed method is superior in improving the incipient fault sensitivity and stability of the degradation index.

Zooplankton community structure in relation to environmental factors and ecological assessment of water quality in the Harbin Section of the Songhua River

To study the relationship between zooplankton community structure and environmental factors and water quality in the Harbin Section of the Songhua River,investigations were carried out in June,August,and October 2011.Canonical correspondence analysis(CCA) and saprobic indices were used to process and analyze the data.Seasonal variability was identified as a significant source of variation,which explains the fluctuation in zooplankton density.In autumn,the dry season,water residence time increased and zooplankton biomass and abundance accumulated in the slow flowing waters.Zooplankton abundance increased when food conditions improved.Therefore,the total zooplankton abundance in autumn is much higher than that in spring and summer.According to the saprobic indices,all the sample sites had mesosaprobic water and water quality was worse in autumn.CCA revealed that temperature accounted for most of the spatial variation in the zooplankton community.Moreover,pH,dissolved oxygen saturation,and turbidity were important factors affecting zooplankton community distribution.

A Critical Analysis of Methodologies Evaluating Biodiversity in Offset Banking

The assessment of ecological impacts represents a key element of biodiversity offsetting success. After briefly introducing the main controversies arisen on biodiversity monetization and defining biodiversity banking schemes, discussions will be focused on evaluation methods mobilized in the context ofbiodiversity offset banking. Although there is currently no fixed framework assessing environment due resolutely to the specific nature of biodiversity, evaluation methods are analyzed through a review of the academic and empirical literature. This step allows to select few methods justifying these choices and presenting their pros and cons by keeping the aim to contribute to the debates. Thus, ecological assessments （service-to-service and resource-to-resource） and economic valuations （value-to-value and value-to-cost） carried out in biodiversity banking schemes will be distinguished. Finally, this paper will emphasize the inherent differences of the two evaluating forms and their specificities on the one hand, and highlight their opportunities and risks from methodological perspective on the other hand.

Urban ecological sustainability assessment of the human-made system and natural system based on emergy and GIS approach

Due to the complexity of sustainable urban research,the environmental sustainability was assessed.Taking the sponge city as an example,the case study was conducted based on the integrated geographic information system(GIS)and emergy methods.The results demonstrate that the emergy of agricultural crops,major industrial products,comprehensive energy products,imports and exports,waste products and increased natural system emergy are the decisive factors for the sustainability assessment.Agricultural crops are the primary contributor,which accounts for 48.9%of the total emergy amount.Urban solid waste has a self-evident superiority in the waste products emergy proportion.Surface water and vegetal biomass emergy possess the pivotal consequences,far higher than soil organic matter.The sewage treatment stations(0.11%)play a small role in the sustainability assessment of the sponge city.The emergy sustainability index is 0.02181,which indicates poor environmental sustainability.According to the study results,increasing renewable energy input proportion and adopting the vegetal biomass of high unit emergy values(UEVs)can improve the sustainability level.

Impact Assessment of Diesel Oil on the Zhe Oyster （Crassostrea plicatula） Using RAPD Analysis

The lethal and sublethal effects of oils on aquatic organisms have been widely investigated, but the potential molecular impacts of oils on aquatic organisms are remaining unclear now. In order to realize the effects of diesel oil on the Zhe oyster, the RAPD （random amplified polymorphic DNA） technique was used. RAPD is a useful assay procedure for the detection of genotoxin-induced DNA damage and mutations. In the present study, the Zhe oysters were exposed to diesel oil at different concentrations and for different exposure periods. The results showed that the DNA band change in RAPD profiles of oysters following diesel oil treatment included loss of normal DNA bands, the appearance of new DNA bands and variations in DNA intensity compared to oysters not exposed to diesel oil. The effects of changes to GTS （genome template stability） were time- and concentration-dependent, the GTS of 10 mg/L was 82.46%, 80.70% and 63.15% in the 8, 16 and 32 days, the GTS of 20 mg/L was 75.44%, 71.93% and 56.14% in the 8, 16 and 32 days, the GTS of 40 mg/L was 73.68%, 70.18% and 56.14% in the 8, 16 and 32 days, respectively. The DNA polymorphisms detected by RAPD analysis could be used as a useful biomarker assay for the detection of genotoxic effects in diesel oil pollution on the oysters, and may be useful for environmental contamination risk assessment.

Bridging the Achievement Gap for Students： A Blueprint for Success

The purpose of this research is to identify and examine the achievement gaps between students. Over the past thirty years, emphasis has been placed on achievement levels of students in this country. State test results, SAT Scores, ACT scores and other assessment instruments have been used to determine performance standards and test results for students. Data analyzed for White students compared to African American and Hispanic students have provided critical information in identifying academic progress and skill deficits for all students. This article will highlight some of the achievement gaps which exit among White, African American and Hispanic Students. Recommendations will also be emphasized to help improve student achievement levels in an effort to close the achievement gap.

On multistage flexible comprehensive evaluation of complicated system

The paper analyzed characters of complicated system and discussed the reason of comprehensive evaluation, realization of flexible comprehensive evaluation was researched from prospect of dynamic measure selection of evaluation, balance of functionality and harmony, uncertainty factor. In the end, multistage flexible comprehensive evaluation of complicated system was applied to performance evaluation of firm.