1,391 research outputs found

    Experimental Evaluation of Interchangeability in Soft CSPs

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    In [8], Freuder defined interchangeability for classical Constraint Satisfaction Problems (CSPs). Recently [2], we extended the definition of interchangeability to Soft CSPs and we introduced two notions of relaxation based on degradation # and on threshold # ( neighborhood interchangeability ( NI )and # neighborhood interchangeability (#NI )). In this pae

    On the Computation of Local Interchangeability in Soft Constraint Satisfaction Problems

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    Freuder in (1991) de?ned interchangeability for classical Constraint Satisfaction Problems (CSPs). Recently (2002), we extended the de?nition of interchangeability to Soft CSPs and we introduced two notions of relaxations based on degradation ? and on threshold ? (?neighborhood interchangeability (?NI )and ?neighborhood interchangeability ?NI ). In this paper we study the presence of these relaxed version of interchangeability in random soft CSPs. We give a description of the implementation we used to compute interchangeabilities and to make the tests. The experiments show that there is high occurrence of ?NI and ?NI interchangeability around optimal solution in Fuzzy CSP and weighted CSPs. Thus, these algorithms can be used succesfully in solution update applications. Moreover, it is also showed that NI interchangeability can well approximate full interchangeability (FI )

    Techniques for Bundling the Solution Space of Finite Constraint Satisfaction Problems

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    We study the backtrack-search procedure with forward checking (FCBT) for finding all solutions to a finite Constraint Satisfaction Problem (CSP). We describe how to use dynamic interchangeability to enhance the performance of search and represent the solution space in a compact manner. We evaluate this strategy (FC-DNPI) in terms of the numbers of nodes visited, constraints checked, and solution bundles generated by comparing it, theoretically and empirically, to other search strategies. We show that FC-DNPI is equivalent to search with the Cross Product Representation (FC-CPR) of [Hubbe and Freuder 1992] in terms of the numbers of solution bundles and constraint checks, while it reduces the number of nodes visited. We establish that both strategies are always superior to FC-BT in terms of all three criteria and dynamic bundling is always beneficial. Further, we compare FC-DNPI to the search procedure of [Haselböck 1993], which exploits static, pre-computed interchangeability relations. We show that the former never generates more solution bundles nor expands more nodes than the latter, and often reduces the number of constraint checks. We also propose, without evaluating them, amendments to the strategy of [Haselböck 1993] to improve its performance and reduce the number of constraint checks

    The place of philosophy of law between justice and efficiency

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    A discussion regarding the complex relationship that exists between the concepts of efficiency and justice goes a long way back and raises several relevant arguments. One of them, and it must be rejected in advance, is that justice is in the realm of public law, while efficiency in that of private law. Is it unacceptable that the balance between public and private law leads to the belief of a divided legal system; one system, one set of laws, one legal system. Legislators and judges are responsible for determining a balance and no theory can postulate that the balance will always be found with a simple cut between public and private law to distinguish when the criterion should be justice or when it should be efficiency. It is reductionist to confine the discussion to single goals of efficiency and justice, when human dignity and human rights should also be considered when one is discussing law. Moreover, a discussion limited to only the concepts of justice and efficiency, relies on a belief that the terms are mutually exclusive. Posner has said that the economic analysis of law has limits and philosophy of law plays an extremely important role in this discourse, which must be interdisciplinary. There can be no goal other than the realization of human rights and there can be no justice if not shared by all of mankind

    Multi-Dimensional Models Facilitate Automatic Reformulation: The Case Study of the SET Game

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    In this paper we describe a reformulation strategy for solving multidimensional Constraint Satisfaction Problems (CSPs). This strategy operates by iteratively considering, in isolation, each one of the uni-dimensional constraints in the problem, and exploits the approximate symmetries induced by the selected constraint on the domains in order to enforce this constraint on the simplified problem. We use the game of SET, a combinatorial card game, as a toy problem to motivate our strategy and to explain and illustrate its operation. However, we believe that our approach is applicable to more complex domains of scientific and industrial importance, and deserves more thorough investigations in the future. Our approach sheds a new light on the dynamic reformulation of multidimensional CSPs. Importantly, it advocates that modeling tools for Constraint Programming should allow the user to specify the constraints directly on the attributes of the domain objects (i.e., variables and values) so that their multi-dimensionality can be exploited during problem solving

    Attack of the Cyborgs: Economic Imperialism and The Human Deficit in Educational Policy-Making & Research

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    The term \u27economic imperialism\u27: is generally attributed to an article of that title by Hoover Institution economist Edward Lazear (2000, p. 1), although it is a concept that has long been promoted by University of Chicago economist Gary Becker. The article itself is a celebratory piece that asserts both modern economics bona fides as the premiere social science analogous to the so-called hard sciences, such as physics and chemistry, as well as the generalized applicability of neoclassical economic theory and econometric methods to all manner of social phenomena. Lazear is surely being provocative in proclaiming the preeminence of economic orthodoxy, not to mention displaying a good deal of intellectual hubris, but it is equally clear that he does have a point. While the assertion that economics is the premiere social science is certainly questionable, it is difficult to understate the growing influence of neoclassical economic theory and methodology across the social sciences (Fine & Milonakis, 2009)

    Stackelberg security games: Looking beyond a decade of success

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