共查询到20条相似文献，搜索用时 968 毫秒
1.
In the study on finding a group of inital values for solving operator equation x=G(x)by the two-sided iterative method,some stronger conditions forG(x)have been demandedand some new parameters have to be introduced since 1978,But,as it will be proved in this paper,Itis unnecessary to use any new parameters and other stronger conditions to get a group of initial val-ues of two-sided iterative, as those initial values can be obtained by means of an auxiliary iterativebeginning with operator G(x)itself. The numerical example in this paper illustraves that the methodproposed in this paper is a general method. 相似文献
2.
In order to improve the node localization precision of Range Free based DV Hop localization algorithm in wireless sensor networks (WSNs) with randomly distributed nodes and dynamic topology, the improved algorithm is proposed. After analyzing the DV Hop algorithm, considering the obvious errors of the estimated node coordinates calculated by Polygon based method in traditional DV Hop algorithm, the numerical iterative algorithm is constructed by employing Taylor series expansion, and simulation studies for the improved DV Hop algorithm are conducted. The selection criteria for the convergent threshold of iterative step is determined, the localization performance of the improved localization algorithm is analyzed by comparing with the traditional DV Hop algorithm under the same condition of selected convergent threshold and simulation parameters, while the calculation amount and convergence rate of the improved algorithm are also measured by the statistic iterations. The simulation results show that by selecting reasonable iterative threshold values and appropriately increasing calculation amount for node localization, the improved DV Hop localization algorithm greatly improves the localization precision and the error stability, which is feasible for node localization in WSNs with both randomly distributed nodes and dynamic topology. 相似文献
3.
Joint Detection technology is a hot point in the research of TD-SCDMA system. Because of a SNR degradation, JD can not reach the need of system performance when system loads is close to the spread factor. MSJD and iterative multi-user detection are put forth to overcome the problem. When iterative MUD is adopted, the research shows that system performance is close to single user performance after 3 iterations, but its computational complexity grows exponentially with the number of code channel. When MSJD is adopted, complexity is reduced compared with iterative MUD, but system performance of code channels numbered K is only close to system performance of code channels numbered K/2 as JD is used. Considering computational complexity and system performance, multi-step iterative multi-user detection technology is brought forth based on iterative MUD and MSJD. According to simulation, the result can be concluded that complexity is reduced compared with single iterative MUD and system performance is improved compared with single MSJD. 相似文献
4.
This paper proposes a novel BP network model based on nonlinear iterative partial least-squares algorithm which can fit nonlinear data. The novel BP network model can reduce iterative step number and advance learning effieieney. This paper pretreats data by nonlinear iterative partial least-squares algorithms. The weights initialization of input floor and output floor are set by applying the loading weights of dependent variable and cause variable, the member of hidden nodes are set by applying factor numbers of nonlinear iterative partial leastsquares algorithm, the connection co- efficient is set by applying the connection matrix B. Performances of the BP, PLS, and PLS-BP are analyzed and compared. The results show that the PLS-BP has better fitting and forecasting than BP and PLS. 相似文献
5.
The iterative Lanczos-reduce method for sensitivity analysis, the Guyan condensed method and the iterative synchronous vector methods in finite element modal are studied in order to solve the dynamic characteristic of complicated machine system. The primary reasons influenced on calculation precision are pointed out. The principia of master freedom for Guyan condensed method are put forward. The calculation precision of three methods is compared with the same standard finite element model. The iterative Lanczos-reduce method for sensitivity analysis is proved to be optimum analysis and the eigenvalue of arm in work device of hydraulic excavator in finite element model is solved with iterative Lanczos-reduce method for sensitivity analysis. The theory basis is provided for reasonable choose to solve the dynamic of complicated machine structure. 相似文献
6.
JIN Mao ming 《保鲜与加工》2003,(6):129-132
We established the generic principle in Banach spaces about unique existence of solutions and approximation of Ishikawa iterative procedures with errors for a class of variational inclusions with strongly accretive type mappings. It is also pointed out that this problem, widely researched approximation of Ishikawa iterative procedures for variational inclusions with strongly accretive type mappings, is only an especied example of Ishikawa iterative procedures with errors. The results are the popularization and deuelopment of the recent corresponding results. 相似文献
7.
Wang Zhijun Liu Nanke 《保鲜与加工》1998,(4):14-20
Based on the extensive study of various iterative methods, a simple but practical way of the iterative route search and acceleration is introduced into the normal displacement and arc-length methods to fit the nonlinear full-range analysis of concrete structures, by which the convergence of iteration is much improved. 相似文献
8.
TIAN You-xian 《保鲜与加工》2004,(12):120-123
Liu Qihou, in 2001 and in 2002, extended the results of Petryshgh and Williamson, Ghosh and Debnath respectively in 1973 and in 1977, proved some sufficient and necessary condition for Ishikawa iterative sequence and for Ishikawa iterative sequence with error member of asymptotically quasi-nonenpansive mappings to converge to fixed poind in Banach space and in uniform convex Banach space. In convex metric spaces,the Ishikawa iteration process with errors is defined for asymptotically quasi-nonexpansive mappings.Some sufficient and nevessary conditions proved for the iterative schene converges to the fixed point of the asymptotically quasi-nonexpansire mappings.These results qeneralize and unify many important known results in recent literature. 相似文献
9.
Marcello Donatelli Gianni Bellocchi Fioravante Fontana 《European Journal of Agronomy》2003,18(3-4):363-367
RadEst3.00 estimates and evaluates daily global solar radiation values at given latitudes. Radiation is calculated as the product of the atmospheric transmissivity of radiation times the radiation outside the earth atmosphere. Four models estimate the atmospheric transmissivity, based on the daily temperature range. Model parameters can be fitted over one or more years of data by iterative procedures. Graphical and statistical evaluations of the estimates are presented. Reports of the analysis can be exported in a variety of formats. Penman–Monteith or Priestley–Taylor reference evapotranspiration is estimated, using both measured and estimated radiation. Utilities are provided to process numerous files, or correct possible constant biases in the data. Samples of data for tropical and temperate sites are supplied with the software. 相似文献
10.
To associate the discrete wavelet transform with the continuous wavelet transform, an iterative convolution algorithm is given by analyzing the and scaling function using coefficients of wavelet filter. usually used methods of the computation The way of judging the convergence of improved algorithm on of the wavelet function iterative convolution is given. The advantages of improved algorithm is analyzed. The experimental result shows that the modified algorithm is effective. 相似文献
11.
On the Iteration of Fixed Points for Generalized Quasi-contractive Mapping in p-convex Metric Spaces
The purpose of this paper is to define an Ishikawa iterative scheme for generalized quasi-contractive mappings in p-convex metric spaces and to prove that this iterative scheme converges to the unique fixed point of generalized quasicontractive mappings in p-convex metric space. The results presented in the paper generalize and unify the corresponding results in given by Liu Qin-hou, Xu Hong-kun, Ding Xie-ping, H. E. Rhoades, et al. 相似文献
12.
Han Li Lan Shikui Jiang Kexun 《保鲜与加工》1995,(5):57-73
Solving methods of wind quantity in complex ventilation meshes which includ wind pressure source are researched. A general matrix model of ventilation meshes and new iterative formulas are proposed. Two computing examples are given and the results shows that each branch' s wind quantity can converge the stable value by several times of iteration for any iterative initial value. The proposed model is suitable for wind quantity computation with complex ventilation structure of electric machines. 相似文献
13.
The flame ceiling jet is easily formed while the on fire train stops in the tunnel. The iterative formula is derived to calculate the average temperature of the flame ceiling jet when the fire source is set on the center of the train by establishing a one dimensional model of the unit control volume, and the heat exchange is considered among the flame smoke and the wall of the tunnel and the train. Undetermined coefficients in the iterative formula are determined by small scale model experiments with the scale factor of 1:8 and numerical simulation. The calculated values of temperature by the iterative formula are consistent well with the measured values, and the maximum error of calculation is no more than 7%, which indicates that the iterative formula is reliable. The results show that the distributions of the average temperature of flame ceiling jet are in the exponential form, but there are some differences between that above the train and that in the tunnel. Two prediction formulas for the flame ceiling jet average temperature changing along the longitudinal tunnel are obtained by the sub fitting method. The results can provide reference for the alarm parameter selection, device settings in tunnel, safety evacuation of the passenger, as well as the analysis of the destructive effects on the tunnel lining structure caused by tunnel fire. 相似文献
14.
This paper deals with a kind of iterations,which need to solve the symmetric positive definite systems of linear equations whose matrices of coefficients have varying positive semi-definite tri-diagonal martrix increments. The positive semi-definite tri-diagonal martrix increment is especially divided, an iterative algorithm is presented. It to use the algorithm in the iterative process of repeatedly solving above mentioned system. Wu Zhuzhu has presented an algorithm for diagonal elements with positive increments. The algorithm of this paper which takes martrix increments into account, is the generalization of the algorithm presented by Wu Zhuzhu. 相似文献
15.
不同保鲜模式对生鲜农产品供应链系统利润的影响分析 总被引：2，自引：0，他引：2
针对消费者对生鲜农产品保鲜要求高但企业保鲜意识不足的问题,研究了不同保鲜模式对生鲜农产品供应链系统利润的影响。采用迭代关系表示生鲜农产品新鲜度,依据成员是否保鲜将保鲜模式分为8类,构建不同保鲜模式下的生鲜农产品供应链系统利润模型,并求解不同保鲜模式下生鲜农产品供应链系统的最优决策参数和利润,分析影响供应链系统利润的因素,最后通过数值算例验证模型结论。研究表明,供应链系统三者(生产商、分销商、零售商)均保鲜时利润最大,降低成本或者降低运输时间均可使供应链系统的订货量和利润上升。 相似文献
16.
Li Xianliang Zhou Shouchang Yao Degui 《保鲜与加工》1997,(5):12-15
The inverse problem of circular low frequence electric current field is calculated using simulated and actually measured data by modified iterative equipotential line algorithm. 相似文献
17.
He Yaosan Lin Jingdong Tang Zhuoyao Tong Mingru 《保鲜与加工》1995,(5):7-12
In this paper, the excitation principle and operating characteristics ofasynchronized turbogenerators are analyzed,and adaptive tracing iterative control strategy based on state identification is proposed. In order to apply this control scheme to practice engineering, some primary elements are analyzed and presented for constituting dual-channel automatic excitation control system of asynchronized turbogenerators. Finally, the paper presents the principle structure charts about excitation control system of asynchroized turbogenerators. 相似文献
18.
Huang Wenzhen 《保鲜与加工》1993,(1):25-31
The distribution of tre bearing loads of the domestic 200MW turbine generator set, which depends on their relative positions,have been studied under different supporting conditions. An iterative method has been developed to calculate all of the bearing loads, which takes the structural static indetermination and nonlinearities of the oil film forces into consideration. Variations of the bearing relative positions and their influence on the stability of the rotor-bearing system, have also been discussed. 相似文献
19.
Zhao Yunbin Duan Yurong 《保鲜与加工》1993,(5):125-130
A new globally convergent algorithm was presented for a continuous differen-tiable nonlinear programming by defining a measure function deviating from the Kuhn-Tucker point. With this algorithm which can be used to get the optimum solution of the problem,the optimal lagrangian multiplier corresponding the optimal solution of the problem was also obtained. A new iterative algorithm for quadratic programming is obtained when applying the general algorithm to quadratic programming. Finally,a numerical example was given. 相似文献
20.
The general nonlinear programming with linear constraints was investigated. In the algorithm, the method of contributing set was used. Comparing with the general contributing set method, the descending dimension method was used to solve the sub-problem with equality constraints in iterative procedure and the problem with inequality constraints. The algorithm is effective by the numerical test. Finally, it was proved that the iteration points are descending, when the objective functions are convex. 相似文献