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1.
Taking aecount of shear action between the piston truss the bottom plate, this paper assumes the bottom plate to be a part-ring and supposes that the shear distribution follows the power series law, making the problem to be a problem of mixed boundary condition of part plate. In the paper, the solution of this elastic plane problem is derived. The general expressions of radial displacement of bottom plate are given. The compatible conditions both at the nodes of the lower chord of the truss and at the central cylindrical shell are analyzed.  相似文献   

2.
Based on the selaxaticn t echnique, a new approach to solving quadratic programming is presented in this paper. The idea of parametric programming is introduced in the process of solving the problem,and the optimal solution can be obtained through a finite numfer of search iterations. The features of the proposed method are few regurements for the initial values and little computation. It can also be used to solve the parametric quadratic programming. As an example of application, it is applied to solve a real power secure economic dispatch problem in electric power systems,and its calculation results are given.  相似文献   

3.
Focusing on the problem that affine transformation will exist among the contour images due to variation of the viewpoints, a new approach to extract affine invariant features and matching strategy is proposed for shape recognition. First, the centroid distance and azimuth angle of each boundary point are computed. Then, with a prior defined angle interval, all the points in the neighbor region of the sample point are considered to calculate the average distance for eliminating noise. After that, the centroid distance ratios(CDRs) of any two contour points with angle difference of 180° are achieved as the representation of the shape, which would be invariant to affine transformation. Since the angles of contour points changed non linearly among affine related images, the CDRs should be resampled to build corresponding relationship. It could be regarded as an optimization problem of path planning. In our method, a PSO based path planning model is presented to address this problem. The experimental results demonstrate the efficiency of the proposed method in shape recognition with translation, scaling, rotation, distortion and noise interference.  相似文献   

4.
摘要:“柠檬”问题的存在会导致了农产品市场调节机制的失灵。为促进农产品市场均衡从低效率状态转化为高效率状态,必须解决农产品市场中普遍存在的“柠檬”问题。本文围绕农产品市场“柠檬”问题的解决,对国内外相关的研究文献进行了系统地梳理,并展望了该领域的研究前景。  相似文献   

5.
Aiming at the problem of machining quenched internal helical gears, a method and its equipment are discussed and designed, which is used for machining quenched internal helical gears by EDM. Its characteristic and principle are proposed. The modifying design of the electrode gear and the calculating method of its modification coefficients is presented. Analyzing for the error of the machining equipment is done. The results show that this problem can be solved by EDM, the electrode gear is the modification gear of machined gear and the machining accuracy can be improved by controlling errors.  相似文献   

6.
The conservation of historic buildings and their environment is an unavoidable problem in urban construction. In this paper, the authors give a few new thoughts about the problem. First, the historic buildings are important part of the core power in city competition.Second,the conservation work should be combined with their development. Third, a classified and multilevel system of protection and reuse of old buildings should be set up.  相似文献   

7.
Boundary element method is a numerical method for solving partial differential equations. There are several formulations of boundary element method (BEM) applied to solve a parabolic differential equation.The approach,which employs time- dependent fundamental solution,allows longer time steps in time integration than other approaches,and this can cut down on time for computer implementation with high precision.Domain decomposition method,which decompose the domain that a given problem is to be solved into subdomains,has the advantages of reducing the large problem into smaller ones and reducing the complex problem into simpler ones,and allows parallel computing.An overlapping domain decomposition method is applied combining a boundary element formulation with time-dependent fundamental solution to solve a diffusion equation. Firstly, by domain decomposition, the problem divided into two problems on subdomains, and then the initial-Boundary problems are solved by boundry element method on each subdomain.Some numerical examples are presented to illustrate feasibility and efficiency of the method. The numerical experiments show that the convergence rate of the method is dependent with the overlapping degree of the subdomains.  相似文献   

8.
This paper shows that the problem finding is one of the important phases in management process. The author points out that the managers should pay great attention to problem finding. In order to identify the problems, managers should sense the changes of environment and obtain the instant feedback of the emerging problem in the organization. The partners within the organization should be encouraged to find out the problem and the top managers should be selected to identify the management problems and be equipped with creative and exploitative spirituality.  相似文献   

9.
Solid waste is one of the major pollution sources of environment.Currently,countries all over the world widely make use of market and public administration to solve the problem.Theories of environmental economics and legal science are fully applied to analyze the effects of these two measures,and conclusions can be made according to their respective traits: market has particular effect and function when dealing with problem of solid waste,but its imperfectness makes it necessary to introduce public administration.However, although it plays an important role in making up imperfectness of market,public administration still has inherent shortcomings and must be limited properly.  相似文献   

10.
A new congestion management model based on high low settlement is proposed for the electricity market. The model combines the transaction mechanism and congestion management to eliminate congestion in branches with the minimum equivalent increase in the system regulating fee. The equality constrains are the branch overloads, the generator sensitivities, and the corresponding adjustments, respectively. By introducing the Lagrange multiplier and a relaxation factor, the nonlinear programming problem with constraints can be translated into an unconstrained nonlinear programming problem. The regulating values of the generators thus can be obtained. The proposed algorithm is verified by a 6 bus system.  相似文献   

11.
The transformation of even dimension to non even dimension usually need the special solution of a certain problem. This paper discusses method to find special solution of elastic plane problem is worth for practical purpose. The methods of finding special solution of displacement and stress for elastic plane problem are given for non even limens ion displacement method and stress function method respectively, and the problem are transformed into even dimension. Several concrete special solutions and applications are included.  相似文献   

12.
The conjugate direction method for solving the unconstrained optimization problem is extended to solving the constrained optimization problem by method of differential geomtry.By inducing a new class of affine connections on a constrained sub-manifold, the primary constrched optilnhation problem is converted to a unconstrained local quadratic programming problem.Based on the definition and construction of a new class of generalized conjugate directions, it isproved that optimum value of the primary constrained optimization problem must be located on thegeodesic line which is formed by the conjugate directions mentioned above and can be reached withinfinite searching step. Therefore a new curve search algorithm with generalized conjugate directions isput forward.  相似文献   

13.
This paper compares the empirical relationship between industrial diversity and economic stability across different geographical scales, including counties, states, Economic Areas, and Metropolitan Statistical Areas, in the contiguous U.S. between 2000 and 2014. It is found that this relationship varies greatly when it is analyzed across these four geographical scales. Meanwhile, several scale‐related problems, such as the modifiable areal unit problem and the small population problem, are introduced to economic diversity literature and further discussed with this variability of the diversity–stability relationship. This paper concludes that the spatial scale problem as well as the optimal unit can be study dependent. Thus, when choosing analytical units to quantify regional economic structure for a specific study, future research should pay attention to scale‐related problems.  相似文献   

14.
Zoltán Barabás 《Euphytica》1993,70(1-2):75-76
Summary Chemically induced male sterility cannot be widely used in practice, primarily of the impractibility of regulating the dosage of gametocides under field conditions. A suboptimal dose can result in incomplete male sterility, and consequently self-seeds of the parental genotypes can contaminate the hybrid. The use of too high doses can cause not only male, but also female sterility.This problem can be eliminated through the use of recessive biochemical deficiency mutants (syn. auxotrophs). If the female plant is auxotrophic, all self-or sib-seedlings are eliminated, whereas all hybrid grains are vital.In this way, in the event of incomplete male sterility induced by gametocides, a high-value F1 hybrid seed can be obtained by using auxotrophic mutants. This problem can also be solved in principle in the case of biparental auxotrophy, which has further advantages (blending of parents, etc.).  相似文献   

15.
Analysis of the Range of Effective Bargain   总被引:1,自引:0,他引:1  
This paper should analyses the problem of bargain from the view of the price range. The factors which influences the whole profit in many periods and how to make a successful bargain with a opponent are proposed. But it should be pointed out that the actual factors are different when different people decide. On the other hand, acquiring the information need cost, so this conclusion should be consider carefully.  相似文献   

16.
In this paper, the vortex electric field is computed. It is caused by magnetic field subject to two dimensional change. This problem can't be solved in general physics. Two examples are listed.  相似文献   

17.
水田土壤剖面磷素吸附-解吸特征   总被引:1,自引:0,他引:1  
磷素在土壤剖面中的移动与地下水体环境关系密切,但目前对于磷素在土壤中垂直迁移的机理问题还不清楚,研究从土壤剖面对磷素吸附-解吸的角度对该问题进行了初步的探讨。以水田土壤剖面为研究对象,对剖面不同层次土壤对磷素的吸附-解吸特征进行研究,结果表明:供试土壤剖面不同层次土壤对磷素吸附均可以与简单的Langmuir方程相拟合,表现出相似的吸附机制;吸附态磷均有随深度增加解吸率上升的特点,这种情况可能有利于磷素在土壤剖面中垂直向下移动。  相似文献   

18.
随着经济的发展和消费者需求的增加,养殖业从传统的养殖模式逐步过渡到现代的规模养殖。养殖业技术不断进步,养殖规模不断壮大,这给养殖业的投资者带来了发展的机遇,但是同样也带来了一定的风险,怎么使得养殖企业的风险最小是当今研究的一个重点。文章首先对养殖业的风险类型以及产生的原因进行研究,然后提出规模养殖的贝叶斯决策模型,阐述模型的建立和运用过程,利用贝叶斯理论对于规模养殖存在的风险进行定性和定量的分析,进而运用一个决策案例来阐述贝叶斯模型决策的过程。案例的结果表明贝叶斯决策模型可以很好地解决决策风险问题,对于是否需要获取补充信息也做出了明确的判断,同时对于预测情形下的各种方案也做出了风险计算,从而直观地反映决策方案是否符合风险最小,收益最大原则。文中案例是规模养殖业决策风险中的一个问题,类似风险决策问题可以根据决策模型来解决。文章最后对各种风险问题提出决策建议,以期为养殖业的风险决策提供一个有效的方法。  相似文献   

19.
There are a lot of influencing factors of land price. Method of t-test of regression analysis model can be used to conduct the analysis of significance of influencing factor of land price. In the case of small sample or indefinite error distribution, there is a problem of unlikelihood of statistical referrer. So that, introduce Bootstrap method in the model to increase precision of estimated variance of parameters and reliability of statistical referrer of significance of influencing factor. Take an empirical analysis based on the data of land deal of Chongqing. The result indicates that it is very efficient to solve such problem by Bootstrap method.  相似文献   

20.
Two teeth diffenence cyclodal gears are the key parts in cyclodal reducer. The plate abrasive wheel method which is widely used at home has very low precision and productivity. So it' s the common problem to be immediately solved. The profile grinding technology discussed in this paper has been proved by practical production to be an efficient and economical cycodal gear manufacturing method.  相似文献   

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