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1.
The PPSV (Proportional Pulse in the System Variable) algorithm is a convenient method for the stabilization of the chaotic time series. It does not require any previous knowledge of the system. The PPSV method also has a shortcoming, that is, the determination off. is a procedure by trial and error, since it lacks of optimization. In order to overcome the blindness, GA (Genetic Algorithm), a search algorithm based on the mechanics of natural selection and natural genetics, is used to optimize the λi The new method is named as GAPPSV algorithm. The simulation results show that GAPPSV algorithm is very efficient because the control process is short and the steady-state error is small.  相似文献   

2.
This paper presents a novel intrusion detection model based on fuzzy cluster and immune principle. The original rival penalized competitive learning (RPCI.) algorithm is modified in order to address the problem of different variability of variables and correlation between variables, the sensitivity to initial number of clusters is also solved. Especially, we use the extended RPCL algorithm to determine the initial number of clusters in the fuzzy cluster algorithm. The genetic algorithm is used to optimize the radius deviation for the determination of characteristic function of abnormal subspace.  相似文献   

3.
For a fixed graph F,a graph G is F-saturated if it has no F as a subgraph,but does contain F after the addition of any new edge.The saturation number,sat(n,F),is the minimum number of edges of a graph in the set of all F-saturated graphs with order n.In this paper,we determine the saturation number sat(n,2 P_3∪tP_2)and characterize the extremal graphs for n≥6 t+8.  相似文献   

4.
A new interlacer is used in this paper to investigate the effect of processing conditions on the properties of interlaced yarn. The experimental results show that number of tangles of interlaced yarn changes little with air pressure from 0.2 MPa to 0.5 MPa, and the number of tangles has a maximum value with yarn speed changing. For two yarn directions of entering and leaving yarn guide of interalcer, the yarn speed for the maximum number of tangles is 400 m/rain and 600 m/rain, respectively. The number of tangles changes with air pressure and yarn speed for two yarn directions is compared.  相似文献   

5.
The copy number of 5S rDNA and centromeric sequence RCS2 was determined by extended DNA fiber based fluorescence in situ hybridization (Fiber-FISH) in rice (Oryza sativa ssp. indica cv. Guangluai No. 4) genome. In order to determine the copy number, it is necessary to know the basepair number that a given length DNA fiber contains under a microscope. Therefore, the length of two DNA fragments, in which the basepair number had been already known, was measured. The insert sequence of the tested BAC 38D17 was 136 kb and its extended DNA was 56.4 μm long, 2.41 kb/μm on average, while that of the tested BAC 44B4 was 144.5 kb in total and 55.7 μm long, 2.60 kb/μm on average under the microscope. They were very close to the theoretical value of B-DNA in the Watson-Crick DNA model, which is 2.97 kb/μm. According to the average value of basepair number per μm of the two samples mentioned above, that is, 2.51 kb/μm, it could be estimated that the copy number was about 686 for 5S rDNA and 286-1121 for the centromere sequence RCS2.  相似文献   

6.
Monkey language models are defined for Chinese Phrase Networks, and scale-free features of Chinese Phrase Networks are uncovered. It is pointed out that the ratio of average degree to the total number of nodes (K/N) is close to a constant. Simulation for the evolution of phrase networks indicates that one of the important reasons for power law distributions is the word selection frequency,which, when tuned aptly, can make the monkey language present similar statistic traits as that of natural languages.Power law tails emerge at large k, and the exponent is about 6. Comparison between monkey model and natural language shows that humans are able to use Chinese words resourcesin more effective and compact ways to express their intentions. All the results demonstrate an important fact that the least effort principle is the basis of Chinese Phrase Networks.  相似文献   

7.
Let K 6 be a real cyclic sextic number fields, and K 2, K 3 be its quadratic and cubic subfields. Let h(L) denote the ideal class number of field L. Seven congruences for h -=h(K 6)/h(K 2)h(K 3) are obtained. In particular, when conductor f\-6 of K 6 is prime p, then Ch -≡B p-16B 5(p-1)6 (mod p), where C is an explicitly given constant, and B n is the Bernoulli number. These results for real cyclic sextic fields are an extension of results for quadratic and cyclic quartic fields obtained by Ankeny_Artin_Chowla, Kiselev, Carlitz, Lu Hongwen, Zhang Xianke from 1948 to 1988.  相似文献   

8.
We report some applications of QCD light cone sum rules (LCSR) to B meson weak decays. Special emphasis is on estimates of the form factors for B decays into a pseudoscalar (P)/vector (V) meson, with a certain chiral current correlator. The main new ingredient, as compared with the case of the standard correlators, is that in the operator product expansion calculations, the contributions due to the twist-3 distribution amplitudes of the related light mesons, which are less known and would bring a larger uncertainty to the calculations with the standard correlators, cancel out fully in the B →P case and do out partially in the B → V one. An important observa- tion, which is similar to that in soft collinear effective theory, is made in twist-3 approximation: whereas only one independent form factor is needed for parameterizing the hadronic matrix elements for a B →P transition induced by all the relevant heavy-light quark currents, there exist two independent form factors under the condition of neglecting the terms suppressed by a factor of m^2, for the B → V transition. Therefore, the improved LCSR approach could be of stronger predictive power for the weak form factors. Also, this approach is employed to understand the B →D transitions by introducing a leading twist-2 DA for an energetic D meson, combined with some of other QCD- based approaches. A detailed QCD next-to-leading order calculation of the B →π form factors is presented for an illustrative purpose, and the sum rule results are used to extract the Cabibbo-Kobayashi-Maskawa matrix element IVubl from the latest BaBar data.  相似文献   

9.
10.
At present, the myopia illness of the students (including the students of university, middle schools andprimary schools) is a serious problem. For preventing and curing it, we must search for the developing lowsof myopia illness to provide the theory foundation for researches on and preventions from myopia illness.We provide the mathematial model on describing the poor eyesight of the students after analysing thedeveloping lows of the poor eyesight of the students as follows:where p(r,t) is the student's myopia falling ill rate function at time t and age r, u(r) denotes the initial stagemyopia falling ill rate function and v(t), the baby myopia falling ill rate function. It is a first order quasi-  相似文献   

11.
The edge-based level set model gives no satisfactory results for images with weak edge,and the region-based model performs poorly for intensity inhomogeneity images.In this paper,we propose an improved region-based level set model that integrates both the gradient information and the region information.The proposed model defines a novel external energy term,which consists of gradient information and signed pressure forces function.In order to eliminate the re-initialization procedure of traditional level set model,an internal energy term is also introduced for the level set function to maintain signed distance function.Compared with traditional models,our model is more robust against images with weak edge and intensity inhomogeneity.Experiments on liver segmentation from abdominal CT images demonstrate the effectiveness and accuracy of the proposed method.  相似文献   

12.
Logic Reasoning     
A teacher was giving her pu- pils a lesson on logic(逻辑).“Here is the situation(情景),”she said,“a man is stand- ing up in a boat in the middle of a river,fishing.He loses his bal- ance(平衡),falls in,and begins splashing(泼水)and yelling(叫喊)for help.His wife hears the commotion(喧闹),knows that he can’t swim,and runs down to the bank (河岸).Why did she run to the bank?” A girl raised her hand and asked,“To draw out(提取)all of his savings(存款).”  相似文献   

13.
The main results are as follows: ( i ) For the number of chord diagrams of order n, an exact formula is given. ( ii ) For the number of spine diagrams of order n, the upper and lower bounds are obtained. These bounds show that the estimation is asymptotically the best. As a byproduct, an upper bound is obtained, for the dimension of Vassiliev knot invariants of order n, that is, 1/2 ( n -1)! for any n≥3, and 1/2( n - 1)! - 1/2( n - 2)! for bigger n . Our upper bound is based on the work of Chmutov and Duzhin and is an improvement of their bound ( n - 1)! . For n = 3, and 4,1/2( n - 1)! is already the best.  相似文献   

14.
Sediment incipient velocity(SIV) is a vital parameter for sediment research and river dynamics. This paper describes a novel method of estimating SIV based on the known flow velocity in the movable-bed model experiment. In this method, we use B-mode ultrasound imaging technique to get video images of moving particles and topography under water. By statistical analysis of video images, the relationship between the average number of imaging particles and flow velocity is obtained. The relationship between the change rate of average number and flow velocity is analyzed in sediment incipient process. These relationships are used to estimate the SIV. Lastly, the changed topography verifies the estimated velocity. The results show there is a sudden change in these relationships which can be used to estimate the SIV with high resolution by using a B-mode ultrasound device. The estimated SIV of plastic sands(particle size is about 0.25 mm) is 3.64 cm · s–1 and the estimated SIV of natural sands(particle size is about 0.25 mm) is 5.47 cm · s–1 in the same condition.  相似文献   

15.
A star forest is a forest whose components are stars. The star arboricity of a graph G,denoted by sa( G),is the minimum number of star forests needed to decompose G. Let k be a positive integer. A k-star forest is a forest whose components are stars of order at most k + 1. The k-star arboricity of a graph G,denoted by sak( G),is the minimum number of k-star forests needed to decompose G. In this paper,it is proved that if any two vertices of degree 3 are nonadjacent in a subcubic graph G then sa2( G) ≤2.For general subcubic graphs G, a polynomial-time algorithm is described to decompose G into three 2-star forests. For a tree T and[Δ k, T)/k]t≤ sak( T) ≤[Δ( T)- 1/K]+1,where Δ( T) is the maximum degree of T.kMoreover,a linear-time algorithm is designed to determine whether sak( T) ≤m for any tree T and any positive integers m and k.  相似文献   

16.
The structural synthesis of mechanisms is a prerequisite of mechanical design. Thereby, it is necessary to address special attention to the structural synthesis of mechanisms,especially for the structural synthesis of hybrid kinematic mechanisms( HKMs). This paper presents a very simple yet very effective method of structural synthesis for HKM based on the set theory. The basic concept and mathematical operation of Generalized Function Set( G_F set) are firstly introduced. Based on G_F set,a type synthesis principle for serial mechanisms,parallel mechanisms and HKMs is presented,respectively. Especially,a detailed algorithm of type synthesis for HKM is proposed as well. It is shown that type synthesis of HKM can be developed by the combination of elements of G_F setand rotation axis transfer theorem. In order to demonstrate the applicability of the type synthesis principle presented in the paper,structure synthesis of 2T3 R HKMs are accomplished,where T and R denote translational and rotational degree-of-freedom( DoF),respectively. And further research shows that the structures of 2T3 R HKMs can be categorized into two types,i. e.,G(_F~Ⅰ) and G(_F~Ⅱ).  相似文献   

17.
The instability of the shear layer separated from a circular cylinder is studied with the Reynolds number (Re) of 3000~104 by numerically solving the two-dimensional Navier-Stokes equations. In the wake of the cylinder, primary vortex shedding with natural frequency fs occurs, and the instability of the shear layer with frequency ft develops, which leads to mixing layer eddies and interacts with the primary shedding vortices. However, there remains some uncertainties regarding to the variation of the shear layer characteristic frequency with the Reynolds number. Based on the previous experimental work, several relationships of ft/fs with Re has been proposed including ft/fs~Re0.5 by Bloor, ft/fs~Re0.87 by Wei and Smith and ft/fs~Re0.67 by Prasad and Williamson. The objective of this study is to predict reasonably the relation of the shear layer instability frequency with the Reynolds number based on the present accurate calculation with the high-order schemes and high-resolution spectrum analysis. According to our calculated results, a variation for the normalized shear-layer frequency of the form ft/fs~Re0.69 is predicted numerically, which is in good agreement with a recent experimental measurement of Re0.67 and physical prediction of Re0.7.  相似文献   

18.
This paper analyzes the process of long-run co-movements and stock market globalization on the basis of cointegration tests and vector error correction (VEC) models. The cointegration tests used here allow for structural breaks to be explicitly modeled and breakpoints to be computed on a relative-time basis. The data used in our empirical analysis were drawn from Datastream and comprise the natural logarithms of relative stock market indexes since 1973 for the G7 countries. The main results point to the conclusion that significant causal cointegration effects occur in this context and that there is a long-run relationship that governs the worldwide process of market integration. Globalization, however, is a complex adjustment process and in many cases there is only evidence of weak market integration which means that non-proportional price transmission occurs in the market along with proportional changes. The worldwide markets, as expected, appear to be driven in general by the US stock market.  相似文献   

19.
In order to solve the problem of low signal-to-noise ratio(about 15 d B) in magnetic signal acquisition of banknotes, a new method of magnetic signal acquisition and processing is proposed taking RMB as an example. In this method, weak signa detection is performed to reduce the noise accompanied with the signal. Seven orders of Chebyshev(Ⅰ) filter and the anti-jamming technology are used in the PCB layout, and grounding modes are introduced to reduce the noise of the amplitude waveform. The proposed method reduce the final output noise by 2/3 and the sig nal-to-noise ratio is increased to 24 d B. The experimental results show that the magnetic signal of RMB banknotes are acquired by the circuit stability, which provides an important guarantee for the improvements of the anti-counterfeit and discrimination for banknotes performance.  相似文献   

20.
With technology scaling into nanometer regime, rampant process variations impact visible influences on leakage power estimation of very large scale integrations (VLSIs). In order to deal with the case of large inter- and intra-die variations, we induce a novel theory prototype of the statistical leakage power analysis (SLPA) for function blocks. Because inter-die variations can be pinned down into a small range but the number of gates in function blocks is large(>1000), we continue to simplify the prototype. At last, we induce the efficient methodology of SLPA. The method can save much running time for SLPA in the low power design since it is of the local-updating advantage. A large number of experimental data show that the method only takes feasible running time (0.32 s) to obtain accurate results (3 σ-error <0.5% on maximum) as function block circuits simultaneous suffer from 7.5%(3 σ/mean) inter-die and 7.5% intra-die length variations, which demonstrates that our method is suitable for statistical leakage power analysis of VLSIs under rampant process variations.  相似文献   

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