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1.
The concept of breakpoint graph, known from the theory of sorting by reversal, has been successfully applied in the theory of gene assembly in ciliates. We further investigate its usage for gene assembly, and show that the graph allows for an efficient characterization of the possible orders of loop recombination operations (one of the three types of molecular operations that accomplish gene assembly) for a given gene during gene assembly. The characterization is based on spanning trees within a graph built upon the connected components in the breakpoint graph. We work in the abstract and more general setting of so-called legal strings.  相似文献   

2.
This paper presents a stochastic algorithm with proper stopping rules for nonsmooth inequality-constrained minimization problems. The algorithm is based on an augmented Lagrangian dual problem transformed from a primal one, and it consists of two loops: an outer loop, which is the iteration for the approximate Lagrange multipliers, and an inner loop, which is a nonsmooth unconstrained minimization subroutine. Under mild assumptions, the algorithm is proved to be almost surely convergent.This work was partially supported by the Science Foundation of Ningbo University. The author is grateful to Professor D. Q. Mayne for his help with this work and to two referees for their helpful comments.  相似文献   

3.
A subroutine for automatic numerical integration is presented. The subroutine is developed by changing the basic rule used in an algorithm of P. van Dooren and L. de Ridder. Comparative test results are given.  相似文献   

4.
A new approach to large size network management based on a structured network representation is proposed. Definitions of arc-structured and vertex-structured networks are given and an extension of topological sorting and time computation algorithms is described. A generalization of the concept of vertex-structured networks is discussed.  相似文献   

5.
数控车床可靠性分配模型是一个层次结构,可靠性分配的关键技术是确定结构底层指标关于顶层目标的重要度排序,其前提条件是单准则排序已知.AHP通过构造"两两比较"的"1~9"比例标度判断矩阵A_n为单准则排序提供了合理的数据条件;但是基于A_n一致性检验的特征根排序法因临界值的确定缺乏必要理论基础而受到质疑.改进AHP的FAHP因为没有摆脱"一致性检验"的干扰所以改进并不成功.为了建立与"一致性"无关的单准则排序方法定义具有可加性的评分标度概念,通过标度转换将比例标度判断矩阵A_n转化为评分标度判断矩阵B_n,利用评分标度的可加性在准则C下对n个比较对象排序.因为B_n不是正矩阵所以不存在"一致性概念",因此基于评分标度判断矩阵的排序与"一致性"无关.  相似文献   

6.
7.
ON HOMOGENEOUS RIEMANN BOUNDARY VALUE PROBLEMS OF HIGHER DEGREE   总被引:3,自引:0,他引:3  
0IntroductionThesolutionforlinearmemannboundaryvalueproblemsiswellkn...[1'2].Fornonlinearsimilarproblems,onlythoseofveryparticularformwereconsideredinliterature,e.g.,[3,4,5].Here,thefollowinghomogeneousRiemannboundaryvalueproblemofdegreenwillbediscussed:whereLisasmoothclosedcontourinthecomplexplane,orientedcounter-clockwiselywithitsinterior(eXterior)regionS (S--),aj(t)EH(L)(H5ldercontinuousonL)and.(z)issectionallyholomorphicwithjumpcurveL.Weshallrestrictourselvestothenormalcase,i.e.,ac(t)…  相似文献   

8.
A scheme is presented for external subroutine calls which makes it possible to have microprogrammed subroutines and to allow subroutines written in different languages. The languages may be compiled to different Directly Executed Languages (DELs) with corresponding microprogrammed interpreters. The scheme makes it possible to intercept each external subroutine call so that such actions as parameter validation, microprogram simulation, and statistics collection can be done. The scheme is intended to be working in a Multics-type environment with late dynamic linking, virtual memory, and ring protection. The scheme is adapted to a model of microprogram development which is also presented.  相似文献   

9.
The new concept of cycled numbers is proposed, from which a new loop algebra is properly constructed. Taking account of applicable needs, a few subalgebras of the loop algebras is presented. By employing one of the subalgebras and Tu scheme, a new integrable hierarchy of soliton equations with multi-component potential functions is worked out, which possesses bi-Hamiltonian structures. The method proposed in this paper can be used generally.  相似文献   

10.
面向具有输入约束的非线性不确定系统,根据输入输出有限增益$L_2$稳定的概念,提出了一种新的鲁棒控制Lyapunov函数.根据此概念,在前期研究的广义逐点最小范数控制的基础上,提出了一种对参数不确定性及外部干扰均具有抑制作用的鲁棒广义逐点最小范数控制器设计方法,并研究了其解析形式的求解方法.通过引入``引导函数",新的算法能够在保证鲁棒稳定性的同时更加灵活的考虑各种控制性能指标.最后,通过将新方法与状态相关Riccati方程非线性控制方法相结合验证该方法可用于提高原有控制器的闭环性能,并通过仿真实验验证了方法的可行性及有效性.  相似文献   

11.
The spiral winding conditions for strands and tape are considered for some common geometries. It is shown that in the case of tape three conditions — two equilibrium conditions and a deformation condition — are necessary and sufficient.  相似文献   

12.
In the present study, two new simulation-based frameworks are proposed for multi-objective reliability-based design optimization (MORBDO). The first is based on hybrid non-dominated sorting weighted simulation method (NSWSM) in conjunction with iterative local searches that is efficient for continuous MORBDO problems. According to NSWSM, uniform samples are generated within the design space and, then, the set of feasible samples are separated. Thereafter, the non-dominated sorting operator is employed to extract the approximated Pareto front. The iterative local sample generation is then performed in order to enhance the accuracy, diversity, and increase the extent of non-dominated solutions. In the second framework, a pseudo-double loop algorithm is presented based on hybrid weighted simulation method (WSM) and the Non-dominated Sorting Genetic Algorithm II (NSGA-II) that is efficient for problems including both discrete and continuous variables. According to hybrid WSM-NSGA-II, proper non-dominated solutions are produced in each generation of NSGA-II and, subsequently, WSM evaluates the reliability level of each candidate solution until the algorithm converges to the true Pareto solutions. The valuable characteristic of presented approaches is that only one simulation run is required for WSM during entire optimization process, even if solutions for different levels of reliability be desired. Illustrative examples indicate that NSWSM with the proposed local search strategy is more efficient for small dimension continuous problems. However, WSM-NSGA-II outperforms NSWSM in terms of solutions quality and computational efficiency, specifically for discrete MORBDOs. Employing global optimizer in WSM-NSGA-II provided more accurate results with lower samples than NSWSM.  相似文献   

13.
Methods are described and APL-codes are supplied to find vertices, edges, other faces and facets of polytopes given by point sets. The basic subroutine is a simplicial decomposition version of least distance, i.e. quadratic, programming. Computational experience indicates high efficiency.  相似文献   

14.
Infinite time Turing machines with only one tape are in many respects fully as powerful as their multi‐tape cousins. In particular, the two models of machine give rise to the same class of decidable sets, the same degree structure and, at least for partial functions f : ℝ → ℕ, the same class of computable functions. Nevertheless, there are infinite time computable functions f : ℝ → ℝ that are not one‐tape computable, and so the two models of infinitary computation are not equivalent. Surprisingly, the class of one‐tape computable functions is not closed under composition; but closing it under composition yields the full class of all infinite time computable functions. Finally, every ordinal that is clockable by an infinite time Turing machine is clockable by a one‐tape machine, except certain isolated ordinals that end gaps in the clockable ordinals.  相似文献   

15.
A variable frequency clock (VFC) is an example of a common electronic feedback control system that defies rigorous analysis yet is readily studied by time domain simulation. Composed of several nonlinear as well as linear blocks, continuous and discrete elements, feedback and feedforward paths, such systems are also subject to input and parameter variations of stochastic nature. They are typically conceived by inventive engineers without the benefit of much analysis.Simulating such circuits by representing each component is possible but often unwieldy and of little help to the designer at inception. But, with the help of IBM's Dynamic Simulation Language (DSL/VS), a higher level model is easily coded, rapidly computed and conveniently evaluated by inspection of graphs. This permits accurate performance prediction as well as design optimization with or without man in the loop.A specific clocking scheme, employed in several IBM tape drives, is used as an example of modeling and simulating a hybrid circuit. Block and timing diagrams, complete application program code, and some graphs are given for this sample problem.  相似文献   

16.
A multi-attribute assignment goal-programming model is developed in this paper for the selection and assignment of transfer personnel. Attributes and incentives are used to select the correct type of people from surplus personnel and assign them to vacant positions. The model is illustrated in a simple, exemplary case problem, and the results are interpreted. The model is solved by using a sequential linear goal-programming algorithm and a mixed-integer programming subroutine.  相似文献   

17.
会计数据的网络流分析   总被引:1,自引:0,他引:1  
学者已证明一个会计主体如一家企业、其复式簿记中一级账户记录的数据组成一个矩阵;继而提出了会计回路概念,并认识到会计回路符合网络的某些规律.提出复式簿记系统的矩阵对应于1个网络,该网络存在着网络流.图论中的最大流最小割定理在该网络中同样有效,可以对之求解最大流最小割.最小割的集合是网络中的"瓶颈",直接影响着总的通过流量.计算出最小割的值,找出它由哪些会计分录组成、关联到哪些会计科目、流量是多少,这正是该会计主体运营中的薄弱环节.这是会计史上第一种整体地、定量地分析会计主体运营状况的数学方法.  相似文献   

18.
The purpose of this work is to analyze size effects in the deformation occurring during nanoindentation-tests of thin metallic films on ceramic substrates. It is well known that classical phenomenological theories of plasticity are hardly applicable in cases of very small dimensions of a body [1]. Thus, the dependency of the mechanical behavior of thin films on the thickness can not be studied in the framework of classical theories. In order to simulate numerically the deformation, a specific material model has been chosen which is able to account for size effects. It bases on the theory of ”Mechanism Strain Gradient” (MSG) plasticity [2] in conjunction with the deformation theory of plasticity. The material model has been implemented via the user defined element subroutine (UEL) in the commercial FE code ABAQUS/Standard as a ten-node tetrahedron-element. With the developed subroutine the deformation of thin copper films on Si substrates during nanoindentation-tests has been simulated. Different material models of the indentor (rigid and elastic) as well as different friction conditions between the film and the pyramidal indentor were tested. Furthermore, the influence of an additional oxide layer on the films surface has been analysed. In order to verify the numerical investigations, results from nanoindentation experiments have been used for comparison [4]. The FE simulations for different thicknesses in the range of 100-600nm showed a very good agreement with the experiments. In particular, the size dependency of the force-displacement curves, calculated by using the developed subroutine, is in rather good agreement with experiments. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

19.
This paper introduces a new paradigm in the design of sorting algorithms, viz., fault tolerance. Fault tolerance is an important concept in modern day computing and design workflows must accommodate this need. In general, there are a number of avenues for faults to occur and techniques to address the same; this paper focusses on only one source of faulty behavior, viz., process termination. Process termination, as a cause of faulty behavior, is important from the perspective of various applications in real-time scheduling. In order to measure the effectiveness of a fault tolerant protocol, it is necessary to define a suitable metric and analyze the performance of the protocol with respect to that metric. We measure the “unsortedness” of an array, as characterized by the number of inversion pairs that remain when the sorting algorithm (process) terminates. This paper proposes a new algorithm for sorting called the Randomized QuickMergesort (RQMS) algorithm. RQMS has a higher degree of fault tolerance than either Randomized Quicksort (RQS) or Mergesort (MS), in that fewer inversion pairs remain when it terminates. Likewise, RQMS has a lower comparison overhead than RQS and is more space-efficient than MS. Our empirical analysis, which was conducted over a wide variety of distributions, conclusively establishes that RQMS is the algorithm of choice, when fault tolerance is paramount in the application. This research was supported in part by the Air Force Office of Scientific Research under Contract FA9550-06-1-0050.  相似文献   

20.
Generalizing the concept of difference sets in groups conditions are given for a loop (P, +) (with equality of left and right inverses) and a subset D of P such that (i) the left translates of D and the right translates of -D (the set of inverses for elements of D) resp. are the lines of two projective planes with point set P, forming a double plane (i.e. the lines of one plane are ovals of the other), (ii) the loop operation has a certain geometric interpretation in the double plane.

Walter Benz zum 60. Geburtstag  相似文献   

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