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991.
Artificial neural networks modeling have recently acquired enormous importance in microwave community especially in analyzing and synthesizing of microstrip antennas (MSAs) due to their generalization and adaptability features. A trained neural model estimates response very fast, which is nearly equal to its measured and/or simulated counterpart. Thus, it completely bypasses the repetitive use of conventional models as these models need rediscretization for every minor changes in the geometry, which itself is a time‐consuming exercise. The purpose of this article is to review this emerging area comprehensively for both analyzing and synthesizing of the MSAs. During reviewing process, some untouched cases are also observed, which are essentially required to be resolved for antenna designers. Unique and efficient neural networks‐based solutions are suggested for these cases. The proposed neural approaches are validated by fabricating and characterizing of the prototypes too. © 2015 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:747–757, 2015. 相似文献
992.
Fractional Order Modeling of Human Operator Behavior with Second Order Controlled Plant and Experiment Research 下载免费PDF全文
Jiacai Huang YangQuan Chen Haibin Li Xinxin Shi 《IEEE/CAA Journal of Automatica Sinica》2016,3(3):271-280
Modeling human operator's dynamics plays a very important role in the manual closed-loop control system, and it is an active research area for several decades. Based on the characteristics of human brain and behavior, a new kind of fractional order mathematical model for human operator in single-input single-output (SISO) systems is proposed. Compared with the traditional models based on the commonly used quasilinear transfer function method or the optimal control theory method, the proposed fractional order model has simpler structure with only few parameters, and each parameter has explicit physical meanings. The actual data and experiment results with the second-order controlled plant illustrate the effectiveness of the proposed method. 相似文献
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994.
为了更加全面地了解和掌握水轮机调速系统的组成结构和不同工况下的特性,在大量研究理想条件下水轮机调节系统建模与仿真结果的基础上,对水轮机调节系统进行线性和非线性建模,并运用matlab/simulink对水轮机调节系统的线性和非线性动态特性进行仿真研究,从而得到了线性条件下空载频率波动和功率扰动波动响应曲线以及非线性环节的系统响应,并对这2种条件下的转速和接力器行程曲线进行了对比分析。分析结果表明,在小波动情况下适合运用线性模型,在大波动情况下适合运用非线性模型,而且这2种情况下得到的结果相差无几,均能反映同一系统的动态过程。该结论将有助于水轮机调节系统在不同工况下的控制。 相似文献
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《Advanced Engineering Informatics》2015,29(4):1013-1027
In recent years, there have been significant advances in modeling technology for object-oriented building products. However, the building models are still lacking of providing construction-specific spatial information required for construction planning. Consequently, construction planners visually analyze building product models and derive geometric characteristics such as bounded spaces and exterior perimeter to develop detailed construction plans. Such a process presents fragmented information flows, from building product information to construction planning, that rely on subjective decisions of construction planners. In order to overcome these drawbacks, this research proposes a geometric reasoning system that analyzes geometric information in building designs, derives the construction-specific spatial information, and uses the information to assist in construction planning. The scope of presented work includes detecting work packages formed by faces during construction, such as large work faces and bounded spaces, and using information in the work packages directly to support planning of selected indoor construction activities. The main features of the proposed system named Construction Spatial Information Reasoner (CSIR) include a set of relationship acquisition algorithms, building component relationship data structure, and interpretation of the relationship to support detailed construction activity planning. The relationship acquisition algorithms identify adjacency between building components that is stored in the relational data structure. Then, acquired adjacency relationships are transformed into a set of graphs that represent work packages. To implement the proposed approach, CSIR utilized a commercially-available Building Information Modeling (BIM) platform and the algorithms were imbedded to the BIM platform. For validation, CSIR was tested on a real commercial building. For interior ceiling grid installation activities, CSIR successfully detected existing work packages and analyzed the spatial characteristics impacting construction productivity. The major contribution of the presented research would be to enable a realistic analysis of building geometric condition that is not possible in current BIM and a seamless information flow from building product information to construction process plans. These can potentially reduce current manual and error-prone construction planning processes. Limitations and future research suggestions are also presented. 相似文献
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根据飞行视景仿真和某飞行器模型的特点,利用Multigen Creator对导入的三维机械模型进行重新建模和优化。从如何修改模型数据库结构和减少模型复杂度和尺寸等方面入手,对飞行器的视景三维仿真模型的建立和优化方法进行了研究,解决了模型的逼真度和视景仿真的实时渲染速度之间的矛盾,最后对优化前后的模型通过在飞行视景仿真实验中的调用得到对比参数,表明了这种优化策略对提高复杂模型驱动速度、仿真效果和节省计算机资源开销有着很大必要性。 相似文献
1000.