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In this paper we present control design methods that provide desirable levels of performance and simultaneously account for actuator and sensor reliability (or malfunction) for buildings under seismic excitations. Performance is defined in terms of the disturbance attenuation (i.e. L2 gain) from the disturbances to the controlled outputs of the system. The reliability of actuators and sensors refers to the deviation of actual control forces or actual sensor measurements from their ideal levels. Simulation results for a six‐storey building are used to demonstrate the effectiveness of the control analysis and design method presented. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
473.
Yixiong Wen Mónica Sánchez-Román Yalin Li Chengshan Wang Zhongpeng Han Laiming Zhang Yuan Gao 《Sedimentology》2020,67(6):3333-3354
In past decades, the formation of dolomite at low temperature has been widely studied in both natural systems and cultured experiments, yet the mechanism(s) involved in the nucleation and precipitation of dolomite remains unresolved. Late Eocene dolomitic deposits from core in the upper Niubao Formation (Lunpola Basin, central Tibetan Plateau, China) are selected as a case study to understand the dolomitization process(es) in the geological record. Dolomite formation in Lunpola Basin can be ascribed to a different mechanism forming the large quantities of replacive dolostones in the geological record; and provides a potential fossil analogue for primary dolomite precipitation at low temperature. This analogue consists of an alternation of laminated dolomitic beds, organic-rich and siliciclastic layers; formed in response to intense evaporation interpreted to take place in a continental shallow lake environment. Mineralogical, textural and stable isotopic evaluations suggest that the dolomite from those dense-clotted laminated beds is a primary precipitate. At the nanoscale, these dolomitic beds are composed of Ca–Mg carbonate globular nanocrystals (diameter 80 to 100 nm) embedded in an organic matrix and attached to clay flakes. Micro-infrared spectroscopy analyses have revealed the presence of aliphatic compounds in the organic matrix. Microscopic and elemental compositional studies suggest that clay surfaces may facilitate the nucleation of dolomite at low temperature in the same way as the organic matrix does. The dolomite laminae show values for δ18OVPDB from −3.2 to −1.76‰ and for δ13CVPDB from −2.62 to −3.78‰. Inferred δ18OSMOW values of the lake water reveal typical evaporitic hydrological conditions. These findings provide a potential link to primary dolomite formation in ancient and modern sedimentary environments; and shed new light on the palaeoenvironmental conditions in central Tibet during the Eocene. 相似文献
474.
This paper uses an associative memory approach to identify the properties of structural and mechanical systems. The methodology differs from standard identification methods in that it uses a set of parameter vectors simultaneously to generate the estimated parameter vector. The method develops a technique for sequentially generating genetically engineered relevant parameter vectors whose use results in accurate identification, while still using small data sets. This makes the approach promising for on-line, rapid, identification of structures and their health monitoring. © 1998 John Wiley & Sons, Ltd. 相似文献
475.
为了进一步开发煤系致密砂岩气,对影响致密砂岩气开采潜力的各种因素进行了综合研究,确立了临兴地区山西组致密砂岩气开采潜力评价的3个二级指标(富集、高渗及可采性)及10个三级指标。根据层序地层体系域发育程度,采用模糊决策两两矩阵和灰色关联分析相结合的方法建立了致密砂岩储层评价模型,利用层序地层单元对砂岩储层进行评价,实现了有利储层的精细划分。结果表明:两两矩阵方法与灰色关联分析方法相结合既提高了"高渗"类别6个三级指标数据之间的关联性,又减少了两两比较法的主观性对参数权重产生的误差;结合层序地层体系域中煤、砂体展布规律,使储层划分、评价更加准确。研究区西南部为山1段开采潜力富集区,东北部为山2段开采潜力富集区。 相似文献
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采用基于物方面元的最小二乘影像匹配方法匹配倾斜影像时,常出现深度不连续或高差较大区域影像连接点度数低或空三点过少问题。针对此问题,本文提出一种基于自适应初始物方面元的倾斜影像匹配算法。算法利用倾斜影像已有的初始内外方位元素及匹配过程中产生的物点信息,采用多片前方交会和物方差分的方法自适应计算物方面元的高程及法向量方向角初值,进而解决采用物方面元最小二乘影像匹配方法匹配地物高差较大区域的倾斜影像时,因初值不准导致在像方匹配同名点困难的问题。分别采用本文算法和物方面元初始状态为水平面元的最小二乘影像匹配方法对两组倾斜影像进行对比匹配验证。试验结果证明了本文算法的有效性。 相似文献
478.
Filtration and cross-flow ultrafiltration techniques were used to separate culture media of Prorocentrum donghaiense at the exponential growth,stationary and decline stages into <0.45 μm filtrate,100 kDa-0.45 μm,10-100 kDa and 1-10 kDa retentate and <1 kDa ultrafiltrate fractions.The fluorescence properties of different molecular weights of dissolved organic matter(DOM) were measured by excitation-emission matrix spectra.Protein-like and humic-like fluorophores were observed in the DOM produced by P.donghai... 相似文献
479.
一种公交换乘优化算法设计 总被引:4,自引:1,他引:3
目前,在智能交通系统应用中,公交查询亟待解决其算法效率和换乘两大问题。对此,本文首先在分析乘客出行因素和公交网络特性的基础上,提出了关键站点的公交网络通达矩阵,分析了直达矩阵的计算原理;其次,阐述了城市道路网络最短路径算法,引入直达矩阵和公交网络通达矩阵,设计了一种公交换乘优化算法。该算法的基本原理:利用公交网络通达矩阵来确定哪些临时标记节点是潜在的永久标记结点,并始终优先考虑直达节点作为最短路径上的节点,从而实现对经典最短路径算法--Dijkstra算法的改进;最后,通过一个案例对该算法进行验证。实验表明,该算法不仅能够获得优于Dijkstra算法的性能,而且换乘次数更加合理。该算法能够适用于一般公交网络,对于换乘代价较高的公交网络更有优势。 相似文献
480.