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961.
T. Clemson T.S. Evans 《Physica A》2012,391(4):1434-1444
We study a networked version of the minority game in which agents can choose to follow the choices made by a neighbouring agent in a social network. We show that for a wide variety of networks a leadership structure always emerges, with most agents following the choice made by a few agents. We find a suitable parameterisation which highlights the universal aspects of the behaviour and which also indicates where results depend on the type of social network. 相似文献
962.
Oesook Lee 《Statistics & probability letters》2012,82(4):812-817
A continuous time asymmetric power GARCH(1,1) model is presented and the V-uniform ergodicity and β-mixing property of the process with exponential decay rate are proved. The V-uniform ergodicity of the COGARCH(1,1) model is obtained as a special case. 相似文献
963.
The aim of this study is to develop new linguistic aggregation operators based on the power-average (PA) operator, such as the linguistic power average (LPA) operator, the linguistic weighted PA operator, and the LPOWA operator. We studied some desired properties of the developed operators, such as idempotency and commutativity. Moreover, we developed two approaches to deal with group decision-making problems under linguistic environments. If the weighting vector of the decision makers was known, we developed an approach based on the linguistic weighted PA operator. On the other hand, if the weighting vector of the decision maker was unknown, we developed a different approach based on the LPOWA operator. We also developed new uncertain linguistic operators under uncertain linguistic environments, such as the ULPA operator, the uncertain linguistic weighted PA operator, and the ULPOWA operator. We extended these approaches, which are based on ULWPA and ULPOWA operators, respectively, to solve group decision-making problems under an uncertain linguistic environment. Finally, a practical example is provided to illustrate the multiple-attribute group decision-making process. 相似文献
964.
This paper presents the design scheme of the indirect adaptive fuzzy observer and controller based on the interval type-2 (IT2) T-S fuzzy model. The nonlinear systems can be well approximated by IT2 T-S fuzzy model, in which the fuzzy rules’ antecedents are interval type-2 fuzzy sets and consequents are linear state equations. The proposed IT2 T-S fuzzy model is a combination of IT2 fuzzy system and T-S fuzzy model, and also inherits the benefits of type-2 fuzzy logic systems, which is able to directly handle uncertainties and can minimize the effects of uncertainties in rule-based fuzzy system. These characteristics can improve the accuracy of the system modeling and reduce the number of system rules. The proposed method using feedback control, adaptive laws, and on-line object parameters are adjusted to ensure observation error bounded. In addition, using Lyapunov synthesis approach and Lipschitz condition, the stability analysis is conducted. The simulation results show that the proposed method can handle unpredicted disturbance and data uncertainties very well in advantage of the effectiveness of observation and control. 相似文献
965.
V.V. Joshi L.B. Xie J.J. Park L.S. Shieh Y.H. Chen K. Grigoriadis J.S.H. Tsai 《Applied Mathematical Modelling》2012
Distributed power grid (DPG) control systems are so highly interconnected that the effects of local disturbances as well as transmission time delays can be amplified as they propagate through a complex network of transmission lines. These effects deteriorate control performance and could possibly destabilize the overall system. In this paper, a new approximated discretization method and digital design for DPG control systems with multiple state, input and output delays as well as a generalized bilinear transformation method are presented. Based on a procedure for the generation of impulse response data, the multiple fractional/integer time-delayed continuous-time system is transformed to a discrete-time model with multiple integer time delays. To implement the digital modeling, the singular value decomposition (SVD) of a Hankel matrix together with an energy loss level is employed to obtain an extended discrete-time state space model. Then, the extended discrete-time state space model of the DPG control system is reformulated as an integer time-delayed discrete-time system by computing its observable canonical form. The proposed method can closely approximate the step response of the original continuous time-delayed DPG control system by choosing various energy loss levels. For completeness, an optimal digital controller design for the DPG control system and a generalized bilinear transformation method with a tunable parameter are also provided, which can re-transform the integer time-delayed discrete-time model to its continuous-time model. Illustrative examples are given to demonstrate the effectiveness of the developed method. 相似文献
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电厂烟气脱硝催化剂VO-WO/TiO失活机理研究 《燃料化学学报》2012,40(11):1359-1365
分别以某电厂失活和新鲜的烟气选择性催化还原(SCR)脱硝催化剂为研究对象,模拟测试催化剂的脱硝效率,并采用扫描电子显微镜-能量色散X射线光谱(SEM-EDX)、X荧光光谱(XRF)、X光电子能谱(XPS)、氮气吸脱附、傅里叶红外光谱(FT-IR)、X射线衍射(XRD)和热重分析(TG)等手段对催化剂的微观结构和表面形态进行表征,探讨了SCR催化剂的失活机制。结果表明,380℃下失活催化剂的脱硝效率(35.0%)和比表面积(1.05 m2/g)明显低于新鲜催化剂(88.2%,72.50 m2/g)。与新鲜催化剂相比,失活催化剂中V5+的比例由17.4%升高到32.2%,并且表面出现了大量的Al2(SO4)3。另外,SEM和XRD结果表明,失活催化剂出现了烧结。催化剂表面V价态的改变、高温烧结和表面Al2(SO4)3相的大量生成是催化剂失活的主要原因。 相似文献
970.
《Liquid crystals》2012,39(12):1763-1768
ABSTRACTWe report the synthesis of 7,7?-disubstituted 2,2?-methylenedioxy-1,1?-binaphthyls and demonstrate their application as chiral dopants in the nematic mixture MLC-6260 to produce highly twisted cholesteric phases. Especially mesogenic and/or polarizable groups in the 7,7?-positions of the bridged binaphthyls generate unusually high helical twisting powers. 相似文献