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It is well known that the soil-structure interaction (SSI) changes the dynamic response of a structure supported on flexible soil. The analysis of optimally controlled SSI systems has certain difficulties due to the nature of the SSI and the optimal control problem. In this paper, a two-step iteration-based numerical algorithm is proposed to handle optimally controlled SSI systems under earthquakes. First, the optimal control forces are obtained by using a fixed-base system. Then, the optimal control forces are converted to the frequency domain by the Fourier transform technique to be used in the equations of the SSI system. The lateral displacement and the rocking of the foundation are obtained from the equations of the SSI system containing the optimal control forces in the frequency domain. The lateral displacement and rocking of the foundation are then converted to the time domain by the inverse Fourier transform technique, and the lateral accelerations and the rocking accelerations of the foundation are obtained by the forward finite difference method. During the second step, the optimal control forces are calculated again by using the lateral acceleration and the rocking acceleration of the foundation along with the earthquake ground motion. Using the method explained above, the optimal control forces obtained in the time domain are used in the equations of the soil-structure system from which the behavior of foundation and structure is obtained. In the final section of the paper, a numerical study is conducted for a controlled structure supported on flexible soil. 相似文献
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Walid Jumblatt Abdullah 《Australian Journal of International Affairs》2016,70(5):525-540
This article attempts to answer the puzzle of why, amongst undemocratic states, some regimes are more authoritarian than others. The author contends that differing party structures result in different authoritarian outcomes. A ruling, competitive authoritarian regime that has a party structure akin to a cadre party, or where there is little or no intra-party democracy, is more likely to be more authoritarian than a party which has intra-party democracy. The lack or absence of intra-party democracy ensures that elites remain cohesive and that there are lesser opportunities for the opposition to take advantage of divisions in the party, whereas in a party with intra-party democracy, there is a greater possibility of elite disunity, which could be capitalised on by the opposition, and there is also a greater likelihood of a different ideology being propagated by defectors from the party. The cases of the People's Action Party in Singapore and the United Malays National Organization in Malaysia are used to illustrate the author's case. 相似文献
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Richard Jennings Ash Parton Huw S. Groucutt Laine Clark‐Balzan Paul Breeze Nick A. Drake Abdullah Alsharekh Michael D. Petraglia 《Arabian Archaeology and Epigraphy》2014,25(1):1-21
Many parts of the Arabian Peninsula contain rock art that has received minimal archaeological attention or has not yet been thoroughly surveyed. In 2001 an extensive rock‐art complex called Shuwaymis, Ha'il Province, Saudi Arabia was brought to the attention of the Saudi General Commission for Tourism and Antiquities. This paper sets out the results of the first high‐resolution geospatial mapping and recording of rock art at this remote site. The research saw the innovative use of a differential GPS to record rock‐art panels to within 5 mm of accuracy at the site of Shuwaymis‐2, the first time that such technology has been used to record rock art in the Arabian Peninsula. With such technology it was possible to show which of eighty‐three late prehistoric rock‐art panels surveyed were in their original position and which had fallen, and to demonstrate that there was spatial homogeneity of rock‐art styles and composition across the site. The mapping recorded multiple panels of cattle, ibex, equid, large cat and other animals. The depictions of lions and cattle in particular indicate that the rock art must have been engraved no later than the early Holocene humid phase (c.10–6 ka BP). 相似文献
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Emma Baysal Adnan Baysal Ali Umut Türkcan Adam Nazaroff 《Oxford Journal of Archaeology》2015,34(3):235-257
An assemblage of marble bracelets, at various stages of manufacture, recovered during surface survey of the site of Kanl?ta? in Turkey, indicates that there was specialized production activity at the site during the Chalcolithic period. In this article we present the assemblage, evidence about material procurement, technology and manufacturing processes. We discuss the significance of the assemblage in relation to other sites in the area and as an example of production intended for inter‐site trade or exchange. We also address the wider issues of both the production of stone bracelets as a widespread practice in Anatolia from the Neolithic onwards, and the phenomenon of early specialized production. 相似文献
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