Designing modular products can result in many benefits to both manufacturers and consumers. The development of modular products requires the identification of highly interactive groups of elements and arranging (i.e.,...
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Designing modular products can result in many benefits to both manufacturers and consumers. The development of modular products requires the identification of highly interactive groups of elements and arranging (i.e., clustering) them into modules. However, no rigorous clustering technique can be found in engineering design literature. This paper uses the design structure matrix (DSM) to visualize the product architecture and to develop the basic building blocks required for the identification of product modules. The DSM architectural representation and building blocks are then used for the development of a new clustering method based on the minimum description length (MDL) principle and a simple genetic algorithm (GA). The new method is capable of partitioning the product architecture into a set of modules where interactions within modules are maximized and interactions outside modules are minimized. We demonstrate the proposed clustering method using several examples of real complex products and compare our results to clustering arrangements proposed by human experts. The proposed method is capable of mimicking the clustering preference of human experts and yields competitive clustering arrangements.
作者：
Tang, HuixuanWei, HuiFudan Univ
Dept Comp Sci Intelligent Informat ProcLab Lab Algorithm Cognit Model Shanghai 200433 Peoples R China
Matching techniques are part-and-parcel of shape recognition. A coarse-to-fine method is presented which finds point correspondence between open or closed curves and is invariant to various image deformations, includi...
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ISBN:
(纸本)9783540709336
Matching techniques are part-and-parcel of shape recognition. A coarse-to-fine method is presented which finds point correspondence between open or closed curves and is invariant to various image deformations, including affine transformation, perspective distortion, non-rigid motion and so forth. The method is inspired by the idea to use point correspondences established at one level to generate a priori information, which is either topological or geometric, to match features at finer levels. This has all been achieved through an analysis of the curve topology and a synthesis of the B-spline interpolation techniques. This is in contrast to existing multi-scale methods for curve matching that use pure feature correlation or 3D structure recovery at a fixed scale. The presented method proves to be robust and accurate and can serve as a powerful aid to measure similarity of shape, as demonstrated in various experiments on real images.
Let M(x) be the summatory function of the Mobius function and R(x) be the remainder term for the number of squarefree integers up to x. In this paper, we prove the explicit bounds |M(x)| = 2160535$ and |R(x)| = 438653...
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Let M(x) be the summatory function of the Mobius function and R(x) be the remainder term for the number of squarefree integers up to x. In this paper, we prove the explicit bounds |M(x)| < x/4345 for x >= 2160535$ and |R(x)| <= 0.02767 root x for x >= 438653. These bounds are considerably better than preceding bounds of the same type and can be used to improve Schoenfeld type estimates.
We analyze generalization and learning in XCS with gradient descent. At first, we show that the addition of gradient in XCS may, slow down learning because it indirectly decreases the learning rate. However, in contra...
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ISBN:
(纸本)9781595936974
We analyze generalization and learning in XCS with gradient descent. At first, we show that the addition of gradient in XCS may, slow down learning because it indirectly decreases the learning rate. However, in contrast to whit was suggested elsewhere, gradient descent has no effect oil the achieved generalization. We also show that when gradient descent is combined with roulette wheel selection, which is known to be sensitive to small values of the learning rate, the learning speed call slow down dramatically. Previous results reported no difference in the performance of XCS with gradient, descent when roulette wheel selection or tournament, selection were used. In contrast, we suggest;that gradient descent should always be combined with tournament selection, which is not sensitive to the value of the learning rare. when gradient descent is used in combination with tournament selection. the results show that (i) the slowdown in learning is limited and (ii) the generalization capabilities of XCS are riot, affected.
In this paper, we study the problem of finding the longest common separable pattern among several permutations. We first give a polynomial-time algorithm when the number of input permutations is fixed and next show th...
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ISBN:
(纸本)9783540734369
In this paper, we study the problem of finding the longest common separable pattern among several permutations. We first give a polynomial-time algorithm when the number of input permutations is fixed and next show that the problem is NP-hard for an arbitrary number of input permutations even if these permutations are separable. On the other hand, we show that the NP-hard problem of finding the longest common pattern between two permutations cannot be approximated better than within a ratio of root opt (where opt is the size of an optimal solution) when taking common patterns belonging to pattern-avoiding permutation classes.
Cellular automata are often used to model systems in physics, social sciences, biology that are inherently asynchronous. Over the past 20 years, studies have demonstrated that the behavior of cellular automata drastic...
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ISBN:
(纸本)9783540744559
Cellular automata are often used to model systems in physics, social sciences, biology that are inherently asynchronous. Over the past 20 years, studies have demonstrated that the behavior of cellular automata drastically changed under asynchronous updates. Still, the few mathematical analyses of asynchronism focus on one-dimensional probabilistic cellular automata, either on single examples or on specific classes. As for other classic dynamical systems in physics, extending known methods from one- to two-dimensional systems is a long lasting challenging problem. In this paper, we address the problem of analysing an apparently simple 2D asynchronous cellular automaton: 2D Minority where each cell, when fired, updates to the minority state of its neighborhood. Our experiments reveal that in spite of its simplicity, the minority rule exhibits a quite complex response to asynchronism. By focusing on the fully asynchronous regime, we are however able to describe completely the asymptotic behavior of this dynamics as long as the initial configuration satisfies some natural constraints. Besides these technical results, we have strong reasons to believe that our techniques relying on defining an energy function from. the transition table of the automaton may be extended to the wider class of threshold automata.
We establish comparison results between the Hasse-Witt invariants w(t)(E) of a symmetric bundle E over a scheme and the invariants of one of its twists E-alpha. For general twists we describe the difference between w(...
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We establish comparison results between the Hasse-Witt invariants w(t)(E) of a symmetric bundle E over a scheme and the invariants of one of its twists E-alpha. For general twists we describe the difference between w(t)(E) and w(t)(E-alpha) up to terms of degree 3. Next we consider a special kind of twist, which has been studied by A. Frohlich. This arises from twisting by a cocycle obtained from an orthogonal representation. A simple important example of this twisting procedure is the bilinear trace form of an etale algebra, which is obtained by twisting the standard/sum-of-squares form by the orthogonal representation attached to the algebra. We show how to explicitly describe the twist for representations arising from very general tame actions. This involves the,square root of the inverse different' which Serre, Esnault, Kahn, Viehweg and ourselves had studied before. For torsors we show that, in our geometric set-up, Jardine's generalisation of Frohlich's formula holds. Namely let (X, G) be a torsor with quotient Y, let E be a symmetric bundle over Y, let rho : G -> O (E) be an orthogonal representation and let E-rho,E-X be the corresponding twist of E. Then we verify up to degree 3 that the formula w(t)(E-rho,E-X)sp(t)(rho) = w(t)(E)w(t)(rho) holds. Here sp(t)(rho) and w(t)(rho) are respectively the spinor invariant and the Stiefel-Whitney class of p. The case of genuinely tamely ramified actions is geometrically more involved and leads us to introduce an invariant of ramification, which in a sense gives a decomposition in terms of representations of the inertia groups of the invariant introduced by Serre for curves. The comparison result in the tamely ramified case proceeds by reduction to the case of a torsor. The reduction is carried out by means of a partial normalisation procedure, which we had introduced in a previous paper. An important lemma of Esnault, Kahn and Viehweg allows us to express the difference between the invariants of bundles before and aft
Knowledge-based problem solving requires a conceptual system that is comparatively rich and complete, especially when the problem is domain *** methods about knowledge acquisition, representation and usage in classica...
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Knowledge-based problem solving requires a conceptual system that is comparatively rich and complete, especially when the problem is domain *** methods about knowledge acquisition, representation and usage in classical Knowledge Engineering can only adapt themselves to domain restricted *** is because it doesn't take a developmental view to construct conceptual system and consequently it is confronted with Framework *** Cognitive Psychology, the study of conceptual system has an in-depth cognitive investigate on issues of development and ***, there lack investigations on the details of system construction and *** on the theory of Developmental Psychology, this paper proposes an object-based representation method for conceptual system, focusing on the representation and development of concepts on four levels: Implicit (I), Explicit 1 (E1), Explicit 2 (E2) and Explicit 3 (E3) *** will contribute well to the adaptability and flexibility in the reasoning and problem solving of knowledge-based systems.
We consider the problem of finding a transitive orientation of a comparability graph, such that the edge set of its covering graph contains a given subset of edges. We propose a solution which employs the classical te...
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We consider the problem of finding a transitive orientation of a comparability graph, such that the edge set of its covering graph contains a given subset of edges. We propose a solution which employs the classical technique of modular tree decomposition. The method leads to a polynomial time algorithm to construct such, an orientation or report that it does not exist. (c) 2006 Elsevier B.V. All rights reserved.
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