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1.
The problem of predicting the short-term future behavior of a sequence, after observing it as long as we please, so as to achieve a specified reliability against all possible sequences is considered. For a particular problem, namely, predicting when in a sequence of 0's and 1's the pair (1, 0) in that order is not coming next, a reliability of 3/4 can be approximated as closely as we please, but not achieved. This article appeared as a Research Memorandum of the Rand Corporation, RM-1570, 12 October 1955.  相似文献   

2.
The Choquet integral w.r.t. a capacity can be seen in the finite case as a parsimonious linear interpolator between vertices of n[0,1]. We take this basic fact as a starting point to define the Choquet integral in a very general way, using the geometric realization of lattices and their natural triangulation, as in the work of Koshevoy.A second aim of the paper is to define a general mechanism for the bipolarization of ordered structures. Bisets (or signed sets), as well as bisubmodular functions, bicapacities, bicooperative games, as well as the Choquet integral defined for them can be seen as particular instances of this scheme.Lastly, an application to multicriteria aggregation with multiple reference levels illustrates all the results presented in the paper.  相似文献   

3.
This study explored sixth grade students’ concept images of geometric translations and the possible sources of their conceptions in a non-technological environment. The data were gathered through a written instrument, student and teacher interviews and document analyses. Analyses of student responses revealed two major concept images of geometric translations: (a) translation as translational motion, and (b) translation as both translational and rotational motion. Students who held these conceptions showed various levels of understanding, such as conceiving translations as undefined motion, partially-defined motion, and defined-motion of a single geometric figure on the plane. The findings of the study suggested, in general, consistencies between students’ concept images and their concept definitions. However, most of the students’ concept definitions were inconsistent with the formal concept definition of geometric translations.Data analyses also revealed five interpretations of a translation vector: (a) vector as a reference line, (b) vector as a symmetry line, (c) vector as a direction indicator, (d) vector as a parameter, and (e) vector as an abstract tool. Furthermore, classroom instruction, mathematics and science textbooks, real-life examples and everyday language were the major sources of students’ concept images of geometric translations.  相似文献   

4.
In this paper, we model a shelf-management problem in which individual products are categorized as part of a product family. It is well known that a product’s shelf location has a significant impact on sales for many retail items. We develop a continuous as well as a discrete model with postprocessing to optimize product placement with consideration given to maintaining the grouping of product families. Computational results are reported on test problems as well as real-world beverage placement problems.  相似文献   

5.
Itay Shani 《Acta Analytica》2010,25(4):413-434
There is a famous passage in chapter six of James’ Principles of Psychology whose import, many believe, deals a devastating blow to the explanatory aspirations of panpsychism. In the present paper I take a close look at James’ argument, as well as at the claim that it underlies a powerful critique of panpsychism. Apart from the fact that the argument was never aimed at panpsychism as such, I show that it rests on highly problematic assumptions which, if followed to their logical consequences, are just as inedible to contemporary critics of panpsychism as they are to its present-day supporters. Hence, a naïve employment of the argument, as a critique leveled by physicalists against panpsychism, is counterproductive and even self-defeating. After examining the metaphysical shortcomings undermining James’ position (as well as the hasty “refutations” of panpsychism based on it), I conclude with some reflections on what needs to be done in order to obtain a better perspective regarding the explanatory prospects of panpsychism as an alternative approach to mainstream physicalism in the study of conscious phenomena.  相似文献   

6.
Vibrations of a beam can be described as an Euler-Bernoulli beam,or as a Rayleigh beam or as a Timoshenko beam. In this paper, we establish the existence of periodic solutions in time for a damped Rayleigh beam model with time delay, which is treated as a bifurcation parameter. The main proof is based on a Lyapunov-Schmidt reduction together with the classical implicit function theorem. Moreover, we give a sufficient condition for a direction of bifurcation.  相似文献   

7.
There has been a growing acceptance of the view that OR can be more appropriately understood as a technology rather than as a science. This view has, however, not been fully developed. This paper seeks to extend this area of investigation by addressing three issues: first, to consider why it is inappropriate to see OR as a science; second, if OR is to be seen as a technology, to ask what model of a technology, the classical or the modern, should be adopted; finally, to explore what implications for understanding OR are held by the most appropriate model of OR as technology. This paper shows that valuable insights might be gained for understanding and guiding the development of OR by seeing it as a technology.  相似文献   

8.
The classical gambler's ruin problem, i.e., a random walk along a line may be viewed graph theoretically as a random walk along a path with the endpoints as absorbing states. This paper is an investigation of the natural generalization of this problem to that of a particle walking randomly on a tree with the endpoints as absorbing barriers. Expressions in terms of the graph structure are obtained from the probability of absorption at an endpoint e in a walk originating from a vertex v, as well as for the expected length of the walk.  相似文献   

9.
We consider a multi-period revenue maximization and pricing optimization problem in the presence of reference prices. We formulate the problem as a mixed integer nonlinear program and develop a generalized Benders’ decomposition algorithm to solve it. In addition, we propose a myopic heuristic and discuss the conditions under which it produces efficient solutions. We provide analytical results as well as numerical computations to illustrate the efficiency of the solution approaches as well as some managerial pricing insights.  相似文献   

10.
民间信仰活动是一种复杂的社会现象,其信众群体是一个独特的社会关系网络。本文在国内首次运用社会网络分析的思维和方法,在对冀南地区民间信仰抽样调查的基础上,建立网络模型,通过对民间信仰主体和客体各结点的中心性、凝聚性等进行量化分析,进而探究民间信仰网络的社会结构及其属性,得出信众群体特征、信仰动因、活动特点、社会心态等有益结论,为民间信仰活动的社会治理和政府管理提供科学依据.  相似文献   

11.
The goal of this article is to inform professional understanding regarding preservice science teachers’ knowledge of engineering and the engineering design process. Originating as a conceptual study of the appropriateness of “knowledge as design” as a framework for conducting science teacher education to support learning related to engineering design, the findings are informed by an ongoing research project. Perkins’s theory encapsulates knowledge as design within four complementary components of the nature of design. When using the structure of Perkins’s theory as a framework for analysis of data gathered from preservice teachers conducting engineering activities within an instructional methods course for secondary science, a concurrence between teacher knowledge development and the theory emerged. Initially, the individuals, who were participants in the research, were unfamiliar with engineering as a component of science teaching and expressed a lack of knowledge of engineering. The emergence of connections between Perkins’s theory of knowledge as design and knowledge development for teaching were found when examining preservice teachers’ development of creative and systematic thinking skills within the context of engineering design activities as well as examination of their knowledge of the application of science to problem‐solving situations.  相似文献   

12.
We develop a multi-stage stochastic programming approach to optimize the bidding strategy of a virtual power plant (VPP) operating on the Spanish spot market for electricity. The VPP markets electricity produced in the wind parks it manages on the day-ahead market and on six staggered auction-based intraday markets. Uncertainty enters the problem via stochastic electricity prices as well as uncertain wind energy production. We set up the problem of bidding for one day of operation as a Markov decision process (MDP) that is solved using a variant of the stochastic dual dynamic programming algorithm. We conduct an extensive out-of-sample comparison demonstrating that the optimal policy obtained by the stochastic program clearly outperforms deterministic planning, a pure day-ahead strategy, a benchmark that only uses the day-ahead market and the first intraday market, as well as a proprietary stochastic programming approach developed in the industry. Furthermore, we study the effect of risk aversion as modeled by the nested Conditional Value-at-Risk as well as the impact of changes in various problem parameters.  相似文献   

13.
We study non-Kähler manifolds with trivial logarithmic tangent bundle. We show that each such manifold arises as a fibre bundle with a compact complex parallelizable manifold as basis and a compactficiation of a semi-torus as fibre.  相似文献   

14.
We define and study an extended hyperbolic space which contains the hyperbolic space and de Sitter space as subspaces and which is obtained as an analytic continuation of the hyperbolic space. The construction of the extended space gives rise to a complex valued geometry consistent with both the hyperbolic and de Sitter space. Such a construction inspires a new concrete insight for the study of the hyperbolic geometry and Lorentzian geometry as a unified object. We also discuss the advantages of this new geometric model as well as some of its applications.  相似文献   

15.
In this article, we first review previous exact approaches as well as theoretical contributions for the problem of reducing the bandwidth of a matrix. This problem consists of finding a permutation of the rows and columns of a given matrix which keeps the non-zero elements in a band that is as close as possible to the main diagonal. This NP-complete problem can also be formulated as a labeling of vertices on a graph, where edges are the non-zero elements of the corresponding symmetrical matrix. We propose a new branch and bound algorithm and new expressions for known lower bounds for this problem. Empirical results with a collection of previously reported instances indicate that the proposed algorithm compares favourably to previous methods.  相似文献   

16.
研究R上不连续函数可作为Sigma-Pi神经网络激励函数的条件,给出了R一局部黎曼可积函数可作为Sigma-Pi神经网络激励函数的特征条件,本文的结果表明:局部黎曼可积函数作为Sigma-Pi神经网络激励函数的特征条件与连续函数时的情形是一致的。  相似文献   

17.
This article presents a study of the connectivities of a graph as a function of other graph parameters such as the number of vertices, the maximum degree, and the diameter. As a result, lower-bounds on the connectivities of a graph as a function of these parameters are computed. These bounds could serve as sufficient conditions for a graph to be h-edge-connected or k-connected. Consequently, the connectivity characteristics of many of the densest known graphs are determined.  相似文献   

18.
We consider a model of a pay-as-bid electricity market based on a multi-leader-common-follower approach where the producers as leaders are at the upper level and the regulator as a common follower is at the lower level. We fully characterize Nash equilibria for this model by describing necessary and sufficient conditions for their existence as well as providing explicit formulas of such equilibria in the market.  相似文献   

19.
Optimal payout policy in presence of downside risk   总被引:1,自引:0,他引:1  
We analyze the determination of a value maximizing dividend payout policy for a broad class of cash reserve processes modeled as spectrally negative jump diffusions. We extend previous results based on continuous diffusion models and characterize the value of the optimal dividend distribution strategy explicitly. We also characterize explicitly the values as well as the optimal dividend thresholds for a class of associated optimal liquidation and sequential lump sum dividend control problems. Our results indicate that both the value as well as the marginal value of the optimal policies are increasing functions of policy flexibility in the discontinuous setting as well.   相似文献   

20.
Justin Chen 《代数通讯》2017,45(5):1907-1913
We show that if a graded submodule of a Noetherian module cannot be written as a proper intersection of graded submodules, then it cannot be written as a proper intersection of submodules at all. More generally, we show that a natural extension of the index of reducibility to the graded setting coincides with the ordinary index of reducibility. We also investigate the question of uniqueness of the components in a graded-irreducible decomposition, as well as the relation between the index of reducibility of a non-graded ideal and that of its largest graded subideal.  相似文献   

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