航空维修信息系统的一种事前评价方法

融合目标规划、网络分析法和集结算子,提出一种航空维修信息系统的事前评价方法.用目标规划处理资源约束,用网络分析法处理相关性,用集结算子将评价者的评价信息集结成群评价信息.选择诱导有序加权欧氏平均算子作为集结算子,并与已有的诱导有序加权调和平均算子、诱导有序加权几何平均算子、诱导有序加权平均算子三种算子进行了对比,结果表明新算子的有效性.给出保序条件下数据分量的可变范围.     

Strongly simplicial vertices of powers of trees

For a tree T and an integer k?1, it is well known that the kth power T^k of T is strongly chordal and hence has a strong elimination ordering of its vertices. In this note we obtain a complete characterization of strongly simplicial vertices of T^k, thereby characterizing all strong elimination orderings of the vertices of T^k.     

On 2min-sets and 2minmax-sets with respect to certain cycles

Let [n] = {1, 2, …, n}. Suppose we have k linear orderings on [n], say <1, <2, …, <k. Let M ? [n]. Then M has a minimum for each linear ordering <i. So M has at most k minima. A set M ? [n] is called a 2min-set if it has at most two different minima in the linear orderings <1, <2, …, <k. Similarly, a set N ? [n] can have at most k minima and k maxima for any k linear orderings. A set N ? [n] is called a 2minmax-set if there exist a, b ∈ N such that all the elements in N | {a, b} lie in between a and b for every linear ordering <i. In this paper, we shall determine the sizes of 2min-sets and 2minmax-sets for certain k linear orderings.     

Dominance of capacities by k-additive belief functions

In this paper we deal with the set of k-additive belief functions dominating a given capacity. We follow the line introduced by Chateauneuf and Jaffray for dominating probabilities and continued by Grabisch for general k-additive measures. First, we show that the conditions for the general k-additive case lead to a very wide class of functions and this makes that the properties obtained for probabilities are no longer valid. On the other hand, we show that these conditions cannot be improved. We solve this situation by imposing additional constraints on the dominating functions. Then, we consider the more restrictive case of k-additive belief functions. In this case, a similar result with stronger conditions is proved. Although better, this result is not completely satisfactory and, as before, the conditions cannot be strengthened. However, when the initial capacity is a belief function, we find a subfamily of the set of dominating k-additive belief functions from which it is possible to derive any other dominant k-additive belief function, and such that the conditions are even more restrictive, obtaining the natural extension of the result for probabilities. Finally, we apply these results in the fields of Social Welfare Theory and Decision Under Risk.     

一种模糊有序加权(FOWA)算子及其应用

针对多个三角模糊数的集结问题，提出一种新的模糊有序加权(FOWA)算子。该算子是对传统OWA算子的扩展，它使三角模糊数可根据其所在排序位置进行集结。分析FOWA算子所具有的性质，给出在群决策中模糊信息集结的一个应用算例。     

Representation of consistent recursive rules

This paper develops the recursive model for connective rules (as proposed in V. Cutello, E. Molina, J. Montero, Associativeness versus recursiveness, in: Proceedings of the 26th IEEE International Symposium on Multiple-valued Logic, Santiago de Compostela, Spain, 29–31 May, 1996, pp. 154–159; V. Cutello, E. Molina, J. Montero, Binary operators and connective rules, in: M.H. Smith, M.A. Lee, J. Keller, J. Yen (Eds.), Proceedings of NAFIPS 96, North American Fuzzy Information Processing Society, IEEE Press, Piscataway, NJ, 1996, pp. 46–49), where a particular solution in the Ordered Weighted Averaging (OWA) context (see V. Cutello, J. Montero, Recursive families of OWA operators, in: P.P. Bonissone (Ed.), Proceedings of the Third IEEE Conference on Fuzzy Systems, IEEE Press, Piscataway, NJ, 1994, pp. 1137–1141; V. Cutello, J. Montero, Recursive connective rules, International Journal of Intelligent Systems, to appear) was translated into a more general framework. In this paper, some families of solutions for the key recursive equation are obtained, based upon the general associativity equation as solved by K. Mak (Coherent continuous systems and the generalized functional equation of associativity, Mathematics of Operations Research 12 (1987) 597–625). A context for the representation of families of binary connectives is given, allowing the characterization of key families of connective rules.     

Bottleneck combinatorial optimization problems with uncertain costs and the OWA criterion

In this paper a class of bottleneck combinatorial optimization problems with uncertain costs is discussed. The uncertainty is modeled by specifying a discrete scenario set containing a finite number of cost vectors, called scenarios. In order to choose a solution the Ordered Weighted Averaging aggregation operator (OWA for short) is applied. The OWA operator generalizes traditional criteria in decision making under uncertainty such as the maximum, minimum, average, median, or Hurwicz criterion. New complexity and approximation results in this area are provided. These results are general and remain valid for many problems, in particular for a wide class of network problems.     

Fuzzy preference orderings in group decision making

In this paper, some use of fuzzy preference orderings in group decision making is discussed. First, fuzzy preference orderings are defined as fuzzy binary relations satisfying reciprocity and max-min transitivity. Then, particularly in the case where individual preferences are represented by utility functions (utility values), group fuzzy preference orderings of which fuzziness is caused by differences or diversity of individual opinions are defined. Those orderings might be useful for proceeding the group decision making process smoothly, in the same manner as the extended contributive rule method.     

On the Parameterized OWA Operators for Fuzzy MCDM Based on Vague Set Theory

The family of Ordered Weighted Averaging (OWA) operators, as introduced by Yager, appears to be very useful in multi-criteria decision-making (MCDM). In this paper, we extend a family of parameterized OWA operators to fuzzy MCDM based on vague set theory, where the characteristics of the alternatives are presented by vague sets. These families are specified by a few parameters to aggregate vague values instead of the intersection and union operators proposed by Chen. The proposed method provides a “soft” and expansive way to help the decision maker to make his decisions. Examples are shown to illustrate the procedure of the proposed method at the end of this paper.     

Probabilistic prospects of Stackelberg leader and follower

In this paper, we consider the family of allm×n bimatrix games, whose payoff entries are the players' orderings of the outcomes, and count the fraction of games whose Stackelberg solution is the leader'sh ^th best outcome and the follower'sk ^th best outcome (h,k≤mn). We conclude that the average leader and follower enjoy symmetric prospects, and that the advantage lies not in the leadership role, but in the relative size of the player's strategy space.     

A Lexicographic 0.5-Approximation Algorithm for the Multiple Knapsack Problem

We present a 0.5-approximation algorithm for the Multiple Knapsack Problem (MKP). The algorithm uses the ordering of knapsacks according to the nondecreasing of size and the two orderings of items: in nonincreasing utility order and in nonincreasing order of the utility/size ratio. These orderings create two lexicographic orderings on A × B (here A is the set of knapsacks and B is the set of indivisible items). Based on each of these lexicographic orderings, the algorithm creates a feasible solution to the MKP by looking through the pairs (a, b) ∈ A × B in the corresponding order and placing item b into knapsack a if this item is not placed yet and there is enough free space in the knapsack. The algorithm chooses the best of the two obtained solutions. This algorithm is 0.5-approximate and has runtime O(mn) (without sorting), where mand n are the sizes of A and B correspondingly.     

Convergence of rank-type equations

Convergence results are presented for rank-type difference equations, whose evolution rule is defined at each step as the kth largest of p univariate difference equations. If the univariate equations are individually contractive, then the equation converges to a fixed point equal to the kth largest of the individual fixed points of the univariate equations. Examples are max-type equations for k = 1, and the median of an odd number p of equations, for k = (p + 1)/2. In the non-hyperbolic case, conjectures are stated about the eventual periodicity of the equations, generalizing long-standing conjectures of G. Ladas.     

The insulation sequence of a graph

In a graph G, a k-insulated set S is a subset of the vertices of G such that every vertex in S is adjacent to at most k vertices in S, and every vertex outside S is adjacent to at least k+1 vertices in S. The insulation sequencei₀,i₁,i₂,… of a graph G is defined by setting i_k equal to the maximum cardinality of a k-insulated set in G. We determine the insulation sequence for paths, cycles, fans, and wheels. We also study the effect of graph operations, such as the disjoint union, the join, the cross product, and graph composition, upon k-insulated sets. Finally, we completely characterize all possible orderings of the insulation sequence, and prove that the insulation sequence is increasing in trees.     

Optimising a nonlinear utility function in multi-objective integer programming

In this paper we develop an algorithm to optimise a nonlinear utility function of multiple objectives over the integer efficient set. Our approach is based on identifying and updating bounds on the individual objectives as well as the optimal utility value. This is done using already known solutions, linear programming relaxations, utility function inversion, and integer programming. We develop a general optimisation algorithm for use with k objectives, and we illustrate our approach using a tri-objective integer programming problem.     

Matrices with maximum kth local exponent in the class of doubly symmetric primitive matrices

Let A be a primitive matrix of order n, and let k be an integer with 1?k?n. The kth local exponent of A, is the smallest power of A for which there are k rows with no zero entry. We have recently obtained the maximum value for the kth local exponent of doubly symmetric primitive matrices of order n with 1?k?n. In this paper, we use the graph theoretical method to give a complete characterization of those doubly symmetric primitive matrices whose kth local exponent actually attain the maximum value.     

Ordering of risks: a review

In this review we will consider and discuss the most important partial orderings of riks, namely consistent partial ordering and net-stop-loss ordering. More especially we will study the consequencies of ordering of risks for the compound risk: S = X₁+X₂+···+X_N.The impact of orderings of claim size distributions (F_X) and claim intensities (F_N) on orderings of claim amounts (F_S) is examined. The consequencies of these kind of orderings on orderings of risks by means of premium calculation principles is also discussed.In this framework the influence of the dangerousness of distributions on orderings of risks is given.In analogy with the notion of stochastic dominance appearing in the theory of finance, the notion of stop-loss dominance is introduced.     

Multivariate order statistics via multivariate concomitants

Let denote a set of n independent identically distributed k-dimensional absolutely continuous random variables. A general class of complete orderings of such random vectors is supplied by viewing them as concomitants of an auxiliary random variable. The resulting definitions of multivariate order statistics subsume and extend orderings that have been previously proposed such as norm ordering and N-conditional ordering. Analogous concepts of multivariate record values and multivariate generalized order statistics are also described.     

Absolutely continuous invariant measures for random maps with position dependent probabilities

A random map is discrete-time dynamical system in which one of a number of transformations is randomly selected and applied at each iteration of the process. Usually the map τ_k is chosen from a finite collection of maps with constant probability p_k. In this note we allow the p_k's to be functions of position. In this case, the random map cannot be considered to be a skew product. The main result provides a sufficient condition for the existence of an absolutely continuous invariant measure for position dependent random maps on [0,1]. Geometrical and topological properties of sets of absolutely continuous invariant measures, attainable by means of position dependent random maps, are studied theoretically and numerically.     

Representation of preference orderings on Lp -spaces by integral functionals: discounting,continuity and TAS utility

This paper presents an axiomatic approach in a continuous time framework for representing preference orderings on L^p -spaces in terms of integral functionals. We show that if preference orderings on L^p -spaces satisfy continuity, separability, sensitivity, substitutability, additivity and lower boundedness, then there exists a utility function for the preference orderings such that the utility function is an integral functional with an upper semicontinuous integrand satisfying the growth condition. Moreover, if the preference orderings satisfy the continuity with respect to the weak topology of L^p -spaces, then the integrand is a concave integrand. As a result, time additive separable (TAS) utility functions with constant discount rates are obtained. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Possibilistic analysis of arity-monotonic aggregation operators and its relation to bibliometric impact assessment of individuals

A class of arity-monotonic aggregation operators, called impact functions, is proposed. This family of operators forms a theoretical framework for the so-called Producer Assessment Problem, which includes the scientometric task of fair and objective assessment of scientists using the number of citations received by their publications.The impact function output values are analyzed under right-censored and dynamically changing input data. The qualitative possibilistic approach is used to describe this kind of uncertainty. It leads to intuitive graphical interpretations and may be easily applied for practical purposes.The discourse is illustrated by a family of aggregation operators generalizing the well-known Ordered Weighted Maximum (OWMax) and the Hirsch h-index.