一种求解Ramsey数的DNA计算机算法

Ramsey理论是组合数学中一个庞大而又丰富的领域,在集合论、逻辑学、分析以及代数学上具有极重要的应用.Ramsey数的求解是非常困难的,迄今为止只求出9个Ramsey数的准确值.探讨了DNA生物分子超级计算在求解这一困难数学问题的可能性.将Adleman-Lipton模型生物操作与粘贴模型解空间相结合的DNA计算模型...     

一种融合多种定位精度改进策略的实时定位中间件

无论是普适计算还是物联网,实时定位均是其关键技术之一。在建筑物、洞室等复杂环境中,由于无线信号的不规则衰减、非视距传播,使得常用的一些定位算法(如接收信号强度、到达角度等)无法达到较高的定位精度。为了解决复杂环境中定位精度不足的问题,设计并实现了一个定位精度改进中间件。它集成了平滑、传感器融合、卡尔曼滤波、粒子滤波等多种精度改进策略,可以根据用户对定位精度的需求动态地选择相应的策略。通过实验分析了不同精度改进策略的性能,结果表明,该中间件能够较好地满足用户对不同精度的需求。     

基于小波神经网络的配电网故障定位研究

在分析小电流接地系统单相接地故障特征的基础上,利用小波分析对非平稳随机信号所具有的优越的时频局部特性和变焦能力来实现提取故障时暂态信息量的特征分量,然后构建出小波神经网络,根据神经网络良好的非线性拟合能力,建立起故障特征分量和故障点位置之间的映射,从而达到故障点精确定位.     

污水处理厂工程自动控制系统

根据唐山市玉田县当地污水水质情况,针对奥贝尔氧化沟污水处理工艺的特点及其处理过程对控制的要求,采用PLC以及其它控制元件,完成对污水处理装置中的粗处理装置、排污泵的启停,氧化沟及沉淀池的控制,以及回流污泥处理系统、除磷加药系统等过程的顺序控制.并对安全系统的紧急停车进行PLC控制处理,从而实现了安全、稳定、高效、低耗的目的.     

Entropy Optimization Filtering for Fault Isolation of Nonlinear Non-Gaussian Stochastic Systems

In this paper, the fault isolation (FI) problem is investigated for nonlinear non-Gaussian systems with multiple faults(or abrupt changes of system parameters) in the presence of noises. By constructing a filter to estimate the states, the FI problem can be reduced to an entropy optimization problem subjected to the non-Gaussian estimation error systems. The design objective for the FI purpose is that the entropy of the estimation error is maximized in the presence of diagnosed fault and is minimized in the presence of the nuisance faults or noises. It is shown that the error dynamics is represented by a nonlinear non-Gaussian stochastic system, for which new relationships are applied to formulate the probability density functions (PDFs) of the stochastic error in terms of the PDFs of the noises and the faults. The Renyi's entropy has been used to simplify the computations in the filtering for the recursive design algorithms. It is noted that the output can be supposed to be immeasurable (but with known stochastic distributions), which is different from the existing results where the output is always measurable for feedback. Finally, simulations are given to demonstrate the effectiveness of the proposed data-driven FI filtering algorithms.     

A new algorithm based on auxiliary virtual topology for sub-path protection in WDM optical networks

This paper proposes a new survivable algorithm named sub-path protection based on auxiliary virtual topology (SPAVT) to tolerate the single-link failure in WDM optical networks. First, according to the protection-switching time constraint, SPAVT searches multiple pairs of primary and backup paths for each node pair in the network by the off-line manner, and then map these paths to the virtual topology. When a connection request arrives, SPAVT only needs to run one time of the Dijkstra’s algorithm to search a virtual route in virtual topology, where the route may consist of multiple pairs of sub-paths, to meet the protection-switching time constraint. Then, according to the shared resources policy, SPAVT chooses an optimal pair of sub-paths. Simulation results show that SPAVT has smaller blocking probability and lower time complexity than conventional algorithms.     

Development of piezoelectric fans for flapping wing application

A piezoelectric fan (piezofan) which couples a piezoelectric unimorph to an attached flexible blade is able to produce a large deflection especially at resonance. The fundamental resonant frequencies (f_r) of the piezofan structures have been calculated by an analytical method and finite element modelling, and these were compared with experimental measurements. Good agreements have been obtained between them. The free tip deflection at quasi-static operation or/and the vibration amplitude at dynamic operation (A) of the piezofans have been experimentally measured. We introduce f_r × A as an optimization criterion for piezofans. Optimization according to this criterion has been carried out for some piezofan configurations, such as the length and the location of the piezo patch, as well as the thickness ratio between the elastic and piezoelectric layers among a few available variations. Results show this optimization approach to be promising when compared to previously defined piezofan performance parameters such as the energy transmission coefficient and electromechanical coupling coefficient.     

Design of a relaying electroosmosis pump driven by low-voltage DC

Electroosmosis pumps (EOPs) have been widely used for manipulating small amounts of reagents for chemical and biological analysis. Traditionally, a high-voltage DC has to be applied in order to achieve the required flow rate. One alternative is to use low AC voltage. Here we propose another solution, which, instead of using a high-voltage DC or low AC voltage, adds a low-voltage DC to an array of electrodes. This design of EOP is called a relaying EOP or cascade EOP. In this study, we intend to push the limit of the low-voltage further down to 2 V by patterning a dense electrode array in a straight microchannel. Two patterns of interdigitated electrodes, symmetric with equal size electrodes and asymmetric with unequal size electrodes, are proposed. Simulations are performed to optimize the distribution and geometrical parameters of the electrode array in order to achieve the maximum flow rate. The proposed low-voltage DC electroosmosis pump shows an advantage in integrating EOP into portable Lab-on-a-chip devices. In addition, the low-voltage DC EOP shows a good promise for in vivo biomedical applications such as drug delivery.