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1.
In computer aided geometric design(CAGD) ,it is often needed to produce a convexity-preserving interpolating curve according to the given planar data points. However,most existing pertinent methods cannot generate convexity-preserving in-terpolating transcendental curves;even constructing convexity-preserving interpolating polynomial curves,it is required to solve a system of equations or recur to a complicated iterative process. The method developed in this paper overcomes the above draw-backs. The basic idea is:first to construct a kind of trigonometric polynomial curves with a shape parameter,and interpolating trigonometric polynomial parametric curves with C2(or G1) continuity can be automatically generated without having to solve any system of equations or do any iterative computation. Then,the convexity of the constructed curves can be guaranteed by the appropriate value of the shape parameter. Performing the method is easy and fast,and the curvature distribution of the resulting interpolating curves is always well-proportioned. Several numerical examples are shown to substantiate that our algorithm is not only correct but also usable.  相似文献   

2.
This paper presents the research on the laws of systematic-parameter dependent variation in the vibration amplitude of drum-brake limit cycle oscillations (LCO). We established a two-degree non-linear dynamic model to describe the low-frequency vibration of the drum brake, applied the centre manifold theory to simplify the system, and obtained the LCO amplitude by calculating the normal form of the simplified system at the Hopf bifurcation point. It is indicated that when the friction coefficient is smaller than the friction coefficient at the bifurcation point, the amplitude decreases; whereas with a friction coefficient larger than the friction coefficient of bifurcation point, LCO occurs. The results suggest that it is applicable to suppress the LCO amplitude by changing systematic parameters, and thus improve the safety and ride comfort when applying brake. These findings can be applied to guiding the design of drum brakes.  相似文献   

3.
For a repairable redundant system consisting of two same components with exponential lifetime and general repair time distribution,the probability densities of the system in some state at time t were determined by a group of ordinary and partial differential equations,called density evolution equations.It was proved that the time-dependent solution of the density evolution equations uniquely exists and strongly converges to its steady state density solution by a semi-group method.In this proof,it is not necessary to suppose that the repair rate function is bounded.The technique of the proof is valuable for many density evolution equatons.  相似文献   

4.
张素敏 《海外英语》2011,(14):280-282
Relational nature of language system is of vital importance in Saussure’s theory of linguistics.As philosopher Ernst Cassirer put that the crucial and revolutionary aspect of modern linguistics was Saussure’s affirmation of the primacy of relation and the system of relations.This paper is devoted to a clear elaboration of the relational nature of linguistic system in terms of three perspectives,namely the arbitrariness of sign,the nature of identity and the linguistic value.It is also suggested that profound understanding of this relational nature facilitate our understanding of its importance not only in linguistics but also beyond linguistics.  相似文献   

5.
Using φ-mapping method and topological current theory,the topological structure of disclination lines in 2-dimensional liquid crystals is studied.By introducing the strength density and the topological current of many disclination lines,it is pointed out that the disclination lines are determined by the singulaities of the director field,and topologically quantized by the Hopf indices and Brouwer degrees,Due to the equivalence in physics of the director fields n(x) and -n(x),the Hopf indices can be integers or half-integers,representing a generalization of our previous studies of integer Hopf indices.  相似文献   

6.
Rule Generation Based on Dominance Matrices and Functions   总被引:2,自引:0,他引:2  
Rough set theory has proved to be a useful tool for rule induction. But, the theory based on indiscemibility relation or similarity relation cannot induce rules from decision tables with criteria. Greco et al have proposed a new rough set approach based on dominance relation to handle the problems. In this paper, the concept of dominance matrix is put forward and the dominance function is constructed to compute the minimal decision rules that are more general and applicable than the ones induced by the classical rough set theory. In addition,the methodology of simplification is presented to eliminate the redundancy in the rule set.  相似文献   

7.
If A and B are two sets,A is said to be a subsetof B if and only if every element of A is also anelement of B.The subset relation is indicated by thesymbolismAB(or BA)which is read“A is a subset of B”or“A is includedin B”or“B includes A”.It is clear from the definition that every set A isa subset of itself.It is important to know that theempty setis the subset of any set A:A.(Wewill explain it in the logic part)Two sets A and B are said to be equal if and  相似文献   

8.
郭杰 《海外英语》2012,(11):144-145
A well-translated instruction manual not only provides complete information related to the products,but also creates aesthetic appealing to bring out purchasing and repurchasing actions.So how to render a qualified and successful instruction manual to the users or consumers is of great significance.Based upon the Skopos theory,this paper is dealing with the translation of instruction manuals in reality.Through analyzing the application of the Skopos rule,the coherence rule and the fidelity rule to translation,it is found that skopos theory are of great guidance to the instruction manual-translating.  相似文献   

9.
A novel posture alignment system for aircraft wing assembly   总被引:2,自引:0,他引:2  
A novel 6-degree of freedom (DOF) posture alignment system, based on 3-DOF positioners, is presented for the assembly of aircraft wings. Each positioner is connected with the wing through a rotational and adsorptive half-ball shaped end-effector, and the positioners together with the wing are considered as a 3-PPPS (P denotes a prismatic joint and S denotes a spherical joint) redundantly actuated parallel mechanism. The kinematic model of this system is established and a trajectory planning method is introduced. A complete analysis of inverse dynamics is carried out with the Newton-Euler algorithm, which is used to find the desired actuating torque in the design and path planning phase. Simulation analysis of the displacement and actuating torque of each joint of the positioners based on inverse kinematics and dynamics is conducted, and the results show that the system is feasible for the posture alignment of aircraft wings.  相似文献   

10.
Study on the Fuzzy COntrol Strategy of Automobile with CVT   总被引:3,自引:0,他引:3  
In order to study the dynamic characteristics of automobile with a CVT system, a bond graph analysis model of continuously variable transmission is established.On the base of the simulation state space equations that are established with bond graph theory,a fuzzy control strategy with an expert system of starting process has been introduced.Considering uncertain system parameters and exterior resistance disturbing,the effect of the profile of membership function and the defuzzification algorthm on the capacity of the fuzzy controller has been studied.The result of simulation proves that the proposed fuzzy controller is effective and feasible,Such controller has been employed in the actual control and has proved practicable.The study lays a foundation for design of the fuzzy controller for automobile with a CVT system.  相似文献   

11.
利用范畴论中范畴与函子的概念,定义了动力系统范畴T到包络半群范畴E的共变函子F1及范畴丁到范畴E*的反变函子F2,并分别讨论了范畴丁中乘积系统的包络半群与范畴E中包络半群直积的一致性及范畴T中逆极限系统的包络半群与范畴E中包络半群逆极限的一致性.  相似文献   

12.
半群S称为E-反演半群,如果对于S中的每-个元素α,存在α∈S,使得ax是S的幂等元。半群S称为E-稠密半群,如果S是E-反演半群并且幂等元相乘可交换。利用E-稠密半群局部化的结论,给出了E-稠密半群上的最小群同余的-个表示及若干等价刻画。在对强仃-逆半群和逆半群上-些结果进行推广的同时,也获得了强仃-逆半群和逆半群上最小群同余的-些新的结论。  相似文献   

13.
研究D-半群的结构性质.借助于Rees序,建立了D-半群范畴和序半群范畴之间的函子,并证明了幂等可换半群范畴ICSGr是D-半群范畴DSGr的余反射子范畴,同时,也研究了D-半群S上的右理想拓扑τS,证明了(S,τS)是T0-空间当且仅当S是幂等可换的半群,并且d=idS.  相似文献   

14.
研究一类IC拟适当半群,即所谓的超拟适当半群。得到了这类半群的若干特征,特别地,建立了超拟适当半群类似于纯正半群的Hall—Yamada结构一种构造方式。最后,考虑了一种特殊情况。  相似文献   

15.
主要介绍正则半群、单半群、逆半群上的偏序关系,对它们的性质作了一些简单的讨论并得到两个关于偏序关系的结论:一个关于周期单半群与完全单半群的关系,另一个是逆半群上定义的序关系与同余关系之间的关系.  相似文献   

16.
S-正则半群     
本文定义了S-正则半群,给出了一个正则半群是S-正则半群的充要条件,讨论了S-正则半群的性质,证明了有S-集的正则半群强半格是S-正则半群的强S-半格.  相似文献   

17.
主要研究局部致密的有界环与左(右)弱均匀半群的关系,且通过改变文献[1]中定理1的条件得到另一个结果。  相似文献   

18.
研究了一类半群,利用半群代数理论及初等数论的方法,给出了一类半群的性质和结构,结合学习内容给出了此类半群的一个实例.  相似文献   

19.
正则半群在半群代数理论中是研究得比较成熟的一类半群,而lpp半群则是较正则半群更广泛的一类半群,它的结构和正则半群有较大的不同.半直积是研究半群结构的一个重要的工具.利用半直积刻画lpp半群的结构,结合lpp半群相关的一些结论,得到了关于lpp半群的半直积及其圈积的结构定理.  相似文献   

20.
设S是半群,A是S-系.首先给出了A的子系是极大子系的充分必要条件;其次利用所定义的L关系,证明了A的非空子集L是A的极大子系的充分必要条件是A\L是A的(极大)L-类;最后,定义了C-子系的概念,讨论了其性质,并利用C-子系刻画了一类S-系.证明了S-系不包含极大子系当且仅当每一个循环子系是C-子系.从而Imrich Fabrici关于半群不包含极大(左)理想的主要结论就是本文的推论.  相似文献   

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