首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 93 毫秒
1.
The reliable fuzzy control with guaranteed cost for T-S fuzzy systems with actuator failure is proposed in this paper. The cost function is a quadratic function with failure input. When the initial state of such systems is known, a design method of the reliable fuzzy controller with reliable guaranteed cost is presented, and the formula of the guaranteed cost is established. When the initial state of such systems is unknown but belongs to a known bounded closed domain, a notion of the reliable domain guaranteed cost (RDGC) for such systems is proposed. For two classes of initial state domain, polygon domain and ellipsoid domain, some design methods for reliable fuzzy controllers with the RDGC are provided. The efficiency of our design methods is finally verified by numerical design and simulation on the Rossler chaotic system.  相似文献   

2.
By the subsuper solutions method, the explosive supersolutions and explosive subsol utions are obtained and the exsistence of explosive solutions is proved on a bounded domain for a class of nonlinear elliptic problems.Then, the exsitence of an entire large solution is proved by the perturbed method.  相似文献   

3.
To efficiently use the array aperture and avoid the complicated parameter pairing computation,this paper proposes a new cumulant-based algorithm for localizing near-field narrowband sources.Firstly,this algorithm proposes a symmetric uniform linear ar- ray (ULA),and constructs three cumulant matrices by using the fourth-order cumulants of some properly chosen sensor outputs;second- ly,unlike the conventional parallel factor (PARAFAC) analysis models in data or subspace domain,it forms a three-way array (TWA) in the fourth-order cumulant domain using the three matrices,and analyzes the uniqueness of its low-rank decomposition;thirdly,it jointly estimates the frequency,the direction-of-arrival (DOA),and the range of each near-field source from the matrices via the low-rank de- composition of the TWA.The simulation results are presented to validate the performance of our proposed method.  相似文献   

4.
The calculation of wave resistance for a ship moving at constant speed near a free surface is considered. This wave resistance is calculated with a linearized steady potential model. To deal with the unboundedness of the physical domain in the potential flow problem, we introduce one vertical side as an artificial upstream boundary and two vertical sides as the artificial downstream boundaries. On the artificial boundaries, a sequence of high-order global artificial boundary conditions are given. Then the potential flow problem is reduced to a problem defined on a finite computational domain, which is equivalent to a variational problem. The solution of the variational problem by the finite element method gives the numerical approximation of the potential flow around the ship, which was used to calculate the wave resistance. The numerical examples show the accuracy and efficiency of the proposed numerical scheme.  相似文献   

5.
In recent years, with the development of 3D data acquisition equipments, the study on reverse engineering has become more and more important. However, the existing methods for parameterization can hardly ensure that the parametric domain is rectangular, and the parametric curve grid is regular. In order to overcome these limitations, we present a novel method for parameterization of triangular meshes in this paper. The basic idea is twofold: first, because the isotherms in the steady temperature do not intersect with each other, and are distributed uniformly, no singularity (fold-over) exists in the parameterization; second, a 3D harmonic equation is solved by the finite element method to obtain the steady temperature field on a 2D triangular mesh surface with four boundaries. Therefore, our proposed method avoids the embarrassment that it is impossible to solve the 2D quasi-harmonic equation on the 2D triangular mesh without the parametric values at mesh vertices. Furthermore, the isotherms on the temperature field are taken as a set of iso-parametric curves on the triangular mesh surface. The other set of iso-parametric curves can be obtained by connecting the points with the same chord-length on the isotherms sequentially. The obtained parametric curve grid is regular, and distributed uniformly, and can map the triangular mesh surface to the unit square domain with boundaries of mesh surface to boundaries of parametric domain, which ensures that the triangular mesh surface or point cloud can be fitted with the NURBS surface.  相似文献   

6.
The phytochrome gene from Microcystis aeruginosa FACHB-912,isolated from algal blooms in Taihu Lake in China,was sequenced and found to code for a wavelength transition light receptor protein.The gene was composed of five distinct domains:a PAS fold domain,a GAF domain,a phytochrome domain,a His Kinase A(phosphoacceptor) domain,and a histidine kinase domain.Red-absorbing phytochrome,far-red-absorbing phytochrome,and photoconversion kinetics were monitored via the spectral characteristics of the protein.To detect positive selection,homologous sequences from cyanobacterium phytochrome genes were obtained from GenBank.Potential selective pressure was identified by phylogenetic analysis with maximum likelihood analyses.The frequency of the phytochrome gene being subjected to selective constraints suggests that positive selection is a potentially important mechanism that promotes the evolution of the cyanobacteria phytochrome gene.The sites identified in this study provide targets for further research on the structural-functional role of these residues,and on the correlation with the mechanism of algal blooms.  相似文献   

7.
The Busemann function plays a very important role in studying topology and geometry of a complete Riemannian manifold. In this paper, the Busemann functions on the real classical domain of the first type and the Cartan domain of the fourth type in the explicit formulas are obtained.  相似文献   

8.
Based on wavelet transform of time-scale domain, a new strain estimation method is presented to position the regular scatterers, calculate the local scatterer spacing and its change, and estimate the internal strain distribution of tissue mimicking phantom. Simulation and experiment results for uniform and nonuniform phantoms show the internal strain of regularly spaced structures can be estimated accurately using this method and the influence of global boundary condition on the estimated strain distribution can be eliminated by reconstructing the real elasticity distribution. This approach has the potentials to become a valuable tool for the regularly spaced structures.  相似文献   

9.
In this paper, we propose a semi-fragile watermarking technology for copyright protection and image authentication. We transform the image into wavelet domain and group the four adjacent wavelet coefficients. Utilizing the characteristics of tile human visual system, we embed a digital signal into the average of the four adjacent wavelet coefficients since the mean has better ,stability than single wavelet coefficient. This method needn‘t original image when extracts the watermark. Experimental results show the effectiveness of this method which is robust to common image process and fragile to malicious attack.  相似文献   

10.
AtCRE1 is known to be a cytokinin receptor inArabidopsis. The AtCRE1 protein contains CHASE domain at the N-terminal part, followed by a transmitter (histidine kinase) domain and two receiver domains. The N-terminal CHASE domain of AtCRE1 contains putative recognition sites for cytokinin. Five CHASE domains containing proteins were found in rice, OsCRLla, OsCRLlb, OsCRL2, OsCRL3, and OsCRL4. OsCRL1a, OsCRL1b, OsCRL2 and OsCRL3 contain the four domains existing in CRE1, whereas OsCRL4 only contains the CHASE domain and a putative Ser/Thr protein kinase domain The authors cloned the encoding gene OsCRL4 and found that it represents a new member of the cytokinin receptor protein in rice.  相似文献   

11.
给出了一种基于RUP(Rational Unified Process)思想的领域本体建模方法论.首先简单介绍了领域本体概念、当前本体建模的方法论及存在的问题,然后通过比较本体建立过程与软件开发过程,提出基于RUP软件开发过程的领域本体构建方法论,并以此方法论为指导,给出一个实例.  相似文献   

12.
基于角色的多级访问控制模型   总被引:12,自引:0,他引:12  
在基于角色的访问控制(role-based access control,RBAC)模型的基础上提出了一种基于角色的多级访问控制模型RBMHAC(role-based multi-hierarchy access control),该模型引入了“域”的概念来根据现实世界中的等级管理体制,通过对“域”用户的安全管理来有效地实现多级安全管理,RBHMAC模型能提供更加完善的访问控制策略,对角色的管理也更加方便高效。  相似文献   

13.
基于膳食平衡指数和营养曲线的个体膳食评价方法   总被引:1,自引:1,他引:0  
针对我国居民膳食营养失衡情况普遍和个体膳食评价方法难被普通人理解的实际应用问题,提出一种基于膳食平衡指数(DBI)和营养曲线的可计算、可理解的个体膳食综合评价方法. 该方法结合基于膳食平衡指数(DBI)的膳食结构评分和基于营养曲线的能量评分方法引入能量权值系数构建个体膳食评价模型. 实验表明,该模型对个体膳食评价准确率为90%,能够为个体膳食提供有效指导;能量和膳食结构评分结果可与慢性疾病高危人群预警模型形成闭环,为疾病的早发现、早干预、健康促进提供有效的膳食干预方法.   相似文献   

14.
陈雷  孟维晓 《应用科技》2011,38(5):22-26
GPS信号捕获是GPS接收机的关键技术,针对常用的GPS接收机中采用的串行滑动相关捕获技术速度慢的缺点,设计了基于FPGA的频域快速捕获算法.与传统的时域相关捕获算法相比,采用FFT技术的频域捕获算法可以快速捕获到多普勒频移及C/A码相位延时.同时使用了系统级建模工具System Generator设计快速捕获算法的FPGA硬件方案,并采用时分复用的方式使每次相关运算共用一个FFT核,节省了大量的硬件资源.  相似文献   

15.
多专业领域是指由多个专业构成的学科领域,如高速铁路领域由工务工程、牵引供电、动车组、运营管理等专业领域构成.对于多专业领域本体的构建,可以先构建各个专业领域本体,然后根据专业领域之间的关系进行本体集成.面向多专业领域,在本体模型的基础上提出了多专业领域本体模型,并给出了多专业领域本体概念语义相似度计算模型,此模型可作为...  相似文献   

16.
为解决传统的基于UDD I注册中心的集中式web服务发现结构存在的可扩展性问题,基于领域本体语义信息,提出一种能自适应地调整领域划分、分配系统资源的分布式web服务发现体系结构.分析了该结构的可扩展性、自组织性和自适应性;描述了基于该结构的语义web服务注册与发现过程;将基于该结构的语义web服务发现算法划分为语义注册中心定位和基于输入输出的服务匹配2个阶段,并具体设计了第1阶段服务发现的3个步骤.通过该两阶段的发现算法可以快速地在分布式环境内定位注册中心,避免消息泛洪导致的网络拥塞.仿真实验结果表明,该服务注册与发现机制在服务规模扩展情况下需要的转发次数较少,且能够保证较高的服务发现效率.  相似文献   

17.
为提高网络域名系统(domain name system, DNS)服务器日志分析能力,综合多种技术提出了构建面向域名解析系统的知识图谱。首先,应用域名解析、权威域名服务器、别名解析、自治系统等基本原理设计了基于aiohttp和dig技术相结合的数据采集方案,构建了相应的领域知识库;其次基于该知识库设计和构建了面向域名解析系统的知识图谱,其节点规模达近500万;然后应用该知识图谱解决web日志中异常访问行为识别效果差的实际问题。以某国家网络信息安全科研机构的网络服务器日志为研究对象,对比是否采用知识图谱进行实验:在爬虫行为、域名暴力解析行为、DNS重复解析行为的识别实验中,F1值分别提高了14.88%、47.23%和91.63%。结果表明,该知识图谱能够有效提高web日志中异常行为识别率。  相似文献   

18.
为了进行汽车平顺性建模和仿真,给出了路面不平度频域模型的标准和改进两种形式。对应路面不平度频域模型改进形式,总结了基于滤波白噪声的路面不平度激励的时域模型。由前后轮路面不平度激励的相关性和一阶Pade算法,建立了前后轮路面不平度激励的时域模型。基于平面系统假设,建立了汽车平顺性四自由度平面系统模型。提出了基于滤波白噪声的汽车平顺性四自由度平面系统仿真算法。在B级路面和常用车速60 km/h下,对某轿车平顺性进行了时域仿真,获得了前轮和后轮路面不平度激励和振动响应量的时间历程。研究结果表明,基于滤波白噪声构造路面不平度激励和对汽车平顺性进行时域建模和仿真是可行和有效的。  相似文献   

19.
文章利用区域分解的迭代方法来解决奇异摄动拟线性对流扩散问题。文中算法是基于有限区域分解方法的,是非常适合并行计算的,且给出了算法的有关收敛特性。  相似文献   

20.
The characteristics of design process, design object and domain knowledge of complex product are analyzed. A kind of knowledge representation schema based o n integrated generalized rule is stated. An AND-OR tree based model of concept f or domain knowledge is set up. The strategy of multilevel domain knowledge acqui sition based on the model is presented. The intelligent multilevel knowledge acq uisition system (IMKAS) for product design is developed, and it is applied in th e intelligent decision support system of concept design of complex product.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号