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板料成形FE中网格节点重构参数曲面的方法研究 被引量:1
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作者 兰凤崇 陈吉清 《塑性工程学报》 EI CAS CSCD 北大核心 2006年第3期19-22,共4页
有限元模拟成形仿真的结果,可以帮助设计开发者正确选择冲压工艺参数和模具形状及材料特性等。在对模拟进行后处理过程中,往往必须了解由有限元节点构成的参数曲面的性质,为后续回弹分析及毛坯设计提供重要支持。如何应用变形后的节点... 有限元模拟成形仿真的结果,可以帮助设计开发者正确选择冲压工艺参数和模具形状及材料特性等。在对模拟进行后处理过程中,往往必须了解由有限元节点构成的参数曲面的性质,为后续回弹分析及毛坯设计提供重要支持。如何应用变形后的节点阵构成光顺的几何曲面是问题的关键。文章给出了由节点序列散点构成非均匀B样条光顺曲面的实际算法,并开发了应用程序。对散乱点数据构成曲面进行了系统的阐述,所开发的方法已经用于板料成形仿真中FE网格节点重构曲面。 展开更多
关键词 板料成形 有限元分析 节点阵 曲面拟合 逼近
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A Layered Zone Routing Algorithm in Ad Hoc Network Based on Matrix of Adjacency Connection
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作者 徐光伟 李峰 +1 位作者 石秀金 霍佳震 《Journal of Donghua University(English Edition)》 EI CAS 2007年第1期43-45,共3页
The hybrid routing protocol has received more attention recently than the proactive and the reactive, especially for large-scale and highly dynamic connection,in mobile ad hoc network. A crucial reason is that zone-la... The hybrid routing protocol has received more attention recently than the proactive and the reactive, especially for large-scale and highly dynamic connection,in mobile ad hoc network. A crucial reason is that zone-layered is being utilized in the complex systems.A hybrid routing algorithm which is layered zone based on adjacency connection(LZBAC) is put forward under the background of a few members in network with steady position and link. The algorithm modifies storage structure of nodes and improves routing mechanism. The theoretical analysis and simulation testing testify that the algorithm costs shorter time of route finding and less delay than others. 展开更多
关键词 Ad Hoc Network adjacency connection masternode routing protocol.
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Full Graph Methods of Switched Current Circuit Solution
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作者 Bohumil Brtnik 《Computer Technology and Application》 2011年第6期471-478,共8页
Circuits with switched current are described by an admittance matrix and seeking current transfers then means calculating the ratio of algebraic supplements of this matrix. As there are also graph methods of circuit a... Circuits with switched current are described by an admittance matrix and seeking current transfers then means calculating the ratio of algebraic supplements of this matrix. As there are also graph methods of circuit analysis in addition to algebraic methods, it is clearly possible in theory to carry out an analysis of the whole switched circuit in two-phase switching exclusively by the graph method as well. For this purpose it is possible to plot a Mason graph of a circuit, use transformation graphs to reduce Mason graphs for all the four phases of switching, and then plot a summary graph from the transformed graphs obtained this way. First the author draws nodes and possible branches, obtained by transformation graphs for transfers of EE (even-even) and OO (odd-odd) phases. In the next step, branches obtained by transformation graphs for EO and OE phase are drawn between these nodes, while their resulting transfer is 1 multiplied by z^1/2. This summary graph is extended by two branches from input node and to output node, the extended graph can then be interpreted by the Mason's relation to provide transparent current transfers. Therefore it is not necessary to compose a sum admittance matrix and to express this consequently in numbers, and so it is possible to reach the final result in a graphical way. 展开更多
关键词 Switched current circuits two phases transformation graph Mason's formula current transfer summary MC-graph
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Smart Home Based on Wireless Sensor-Actuator Networks 被引量:6
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作者 孙岩 陈强 罗红 《China Communications》 SCIE CSCD 2011年第1期102-109,共8页
Wireless sensor-actuator networks can bring flexibility to smart home.We design and develop a smart home prototype using wireless sensor-actuator network technology to realize environmental sensing and the control of ... Wireless sensor-actuator networks can bring flexibility to smart home.We design and develop a smart home prototype using wireless sensor-actuator network technology to realize environmental sensing and the control of electric appliances.The basic motivation of our solution is to utilize the collaboration among a mass of low-cost sensor nodes and actuator nodes to make life convenient.To achieve it,we design a novel system architecture with assembled component modules.In particular,we address some key technical challenges:1) Field-Programmable Gate Array (FPGA) Implementation of Adaptive Differential Pulse Code Modulation (ADPCM) for audio data;2) FPGA Implementation of Lempel Ziv Storer Szymanski (LZSS) for bulk data;3) combination of complex control logic.Finally,a set of experiments are presented to evaluate the performance of our solution. 展开更多
关键词 smart home sensor-actuator network FPGA
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DTMC-based Modeling and Analysis of Obstacle Ad hoc Networks
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作者 Tong Ning Wu Di Wang Xiukun 《China Communications》 SCIE CSCD 2010年第5期83-92,共10页
One of the main characteristics of Ad hoc networks is node mobility, which results in constantly changing in network topologies. Consequently, the ability to forecast the future status of mobility nodes plays a key ro... One of the main characteristics of Ad hoc networks is node mobility, which results in constantly changing in network topologies. Consequently, the ability to forecast the future status of mobility nodes plays a key role in QOS routing. We propose a random mobility model based on discretetime Markov chain, called ODM. ODM provides a mathematical framework for calculating some parameters to show the future status of mobility nodes, for instance, the state transition probability matrix of nodes, the probability that an edge is valid, the average number of valid-edges and the probability of a request packet found a valid route. Furthermore, ODM can account for obstacle environment. The state transition probability matrix of nodes can quantify the impact of obstacles. Several theorems are given and proved by using the ODM. Simulation results show that the calculated value can forecast the future status of mobility nodes. 展开更多
关键词 Ad hoc network discrete time markov chain mobility model OBSTACLE
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Study of the approximate approaches to the POD based spectral representation method 被引量:2
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作者 WU YongXin GAO YuFeng +2 位作者 LI DaYong XU ChangJie MAHFOUZ Ali Hasson 《Science China(Technological Sciences)》 SCIE EI CAS 2013年第4期970-979,共10页
The spectral representation method (SRM) is most widely used in simulating the stochastic field.The proper orthogonal decomposition (POD) based SRM is an important form.This paper investigates the approximate approach... The spectral representation method (SRM) is most widely used in simulating the stochastic field.The proper orthogonal decomposition (POD) based SRM is an important form.This paper investigates the approximate approaches to the POD-based SRM in simulating two typical problems,i.e.,the seismic ground motion and wind velocity fields simulations.Then,the accuracy resulting from the power spectral density matrix-based POD method (PSRM) is compared to that of the coherency matrix-based POD method (CPSRM).It is concluded that the CPSRM maintains a much higher accuracy than the PSRM.In the CPSRM,the linear interpolation of eigenvectors and third-order polynomial interpolation of eigenvalues can be accepted to attain high accuracy;the linearly distributed interpolation nodes are effective in the ground motions simulation;however,the exponentially distributed interpolation nodes are effective in the wind velocity simulation. 展开更多
关键词 stochastic field simulation coherency matrix based spectral representation method proper orthogonal decomposition APPROXIMATION
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