Limit distributions for the problem of collecting pairs

Let $N_n=\{1,2,...,n\}$. Elements are drawn from the set $N_n$ with replacement, assuming that each element has probability $1/n$ of being drawn. We determine the limiting distributions for the waiting time until the given portion of pairs $jj$, $j\in N_n$, is sampled. Exact distributions of some related random variables and their characteristics are also obtained.Comment: Published in at http://dx.doi.org/10.3150/07-BEJ114 the Bernoulli (http://isi.cbs.nl/bernoulli/) by the International Statistical Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm

A separable approximation dynamic programming algorithm for economic dispatch with transmission losses

Copyright @ 2002 University of Belgrade - This article can be accessed from the link below.The standard way to solve the static economic dispatch problem with transmission losses is the penalty factor method. The problem is solved iteratively by a Lagrange multiplier method or by dynamic programming, using values obtained at one iteration to compute penalty factors for the next until stability is attained. A new iterative method is proposed for the case where transmission losses are represented by a quadratic formula (i.e., by the traditional B-coefficients). A separable approximation is made at each iteration, which is much closer to the initial problem than the penalty factor approximation. Consequently, lower cost solutions may be obtained in some cases, and convergence is faster

The continuous p-centre problem: An investigation into variable neighbourhood search with memory

A VNS-based heuristic using both a facility as well as a customer type neighbourhood structure is proposed to solve the p-centre problem in the continuous space. Simple but effective enhancements to the original Elzinga-Hearn algorithm as well as a powerful ‘locate-allocate’ local search used within VNS are proposed. In addition, efficient implementations in both neighbourhood structures are presented. A learning scheme is also embedded into the search to produce a new variant of VNS that uses memory. The effect of incorporating strong intensification within the local search via a VND type structure is also explored with interesting results. Empirical results, based on several existing data set (TSP-Lib) with various values of p, show that the proposed VNS implementations outperform both a multi-start heuristic and the discrete-based optimal approach that use the same local search

Primal-dual variable neighborhood search for the simple plant-location problem

Copyright @ 2007 INFORMSThe variable neighborhood search metaheuristic is applied to the primal simple plant-location problem and to a reduced dual obtained by exploiting the complementary slackness conditions. This leads to (i) heuristic resolution of (metric) instances with uniform fixed costs, up to n = 15,000 users, and m = n potential locations for facilities with an error not exceeding 0.04%; (ii) exact solution of such instances with up to m = n = 7,000; and (iii) exact solutions of instances with variable fixed costs and up to m = n = 15, 000.This work is supported by NSERC Grant 105574-02; NSERC Grant OGP205041; and partly by the Serbian Ministry of Science, Project 1583

DENTAL PATIENTS ON ORAL ANTICOAGULANT THERAPY

Oral anticoagulant therapy (OAT) has been used for more than half a century in themanagement and prevention of thromoembolic disorders. Due to somewhat awkwardphenomena accompanying anticoagulant therapy during dental-surgical interventions,dentists have to be well acquainted with the characteristics of the therapy and themeasures to be undertaken in the management of patients on OAT. This paper aims topresent a short overview of the procedures and measures to be undertaken by a dentistin the management of patients on OAT

Improvements and comparison of heuristics for solving the uncapacitated multisource Weber problem

Copyright @ 2000 INFORMSThe multisource Weber problem is to locate simultaneously m facilities in the Euclidean plane to minimize the total transportation cost for satisfying the demand of n fixed users, each supplied from its closest facility. Many heuristics have been proposed for this problem, as well as a few exact algorithms. Heuristics are needed to solve quickly large problems and to provide good initial solutions for exact algorithms. We compare various heuristics, i.e., alternative location-allocation (Cooper 1964), projection (Bongartz et al. 1994), Tabu search (Brimberg and Mladenovic 1996a), p-Median plus Weber (Hansen ct al. 1996), Genetic search and several versions of Variable Neighbourhood search. Based on empirical tests that are reported, it is found that most traditional and some recent heuristics give poor results when the number of facilities to locate is large and that Variable Neighbourhood search gives consistently best results, on average, in moderate computing time.This study was supported by the Department of National Defence (Canada) Academic Research; Office of Naval Research Grant N00014-92-J-1194, Natural Sciences and Engineering Research Council of Canada Grant GPO 105574 and Fonds pour la Formation des Chercheurs et l’Aide a la Recherche Grant 32EQ 1048; and by an International Postdoctoral Fellowship of the Natural Sciences and Engineering Research Council of Canada, Grant OGPOO 39682

R&D expenditure and economic growth: EU28 evidence for the period 2002–2012

In this paper, we investigate the influence of R&D expenditure on economic growth in the EU28 during the period of 2002–2012. For this purpose, we constructed a multiple regression model, which showed that, ceteris paribus, an increase in R&D expenditure as a percentage of GDP by 1% would cause an increase of real GDP growth rate by 2.2%. This model takes into consideration actual financial crises and emphasises the negative influence of fertility rate in the EU28 on economic growth. We believe that the achieved research results can be beneficial to the economic policy makers in the innovation and demographic areas

Paul Éluard : un épisode yougoslave

The paper discusses the personal and political relations between the French surrealist poet Paul Éluard and Serbian writers and intellectuals, first of all Marko Ristić, a theorist and one of the founders of the Serbian surrealist movement. We will show the reception of Éluard’s works in the Serbian cultural space, his visit to Yugoslavia, then Éluard’s activities in Paris related to Yugoslav politics. One significant part of the article represents, until now, unpublished archival documents that testify to the friendship between Éluard and Ristić. We will try to explain how this friendship ended after the Cominform Resolution in 1948 and what consequences it had on Serbian and French culture.Dans un premier temps l’auteur se penchera sur les relations littéraires, politiques et personnelles qu’entretenait Paul Éluard, écrivain surréaliste français, avec certains auteurs yougoslaves et serbes. Ensuite, cet article s’attachera à mettre en lumière la réception des œuvres du poète dans le milieu culturel serbe. Pour ce faire nous nous appuierons sur le manuscrit d’un poème inédit déposé à l’Académie serbe des sciences et des arts qui témoigne des relations étroites qu’entretenait le poète avec le fondateur et théoricien du surréalisme serbe Marko Ristić

An interior point algorithm for minimum sum-of-squares clustering

Copyright @ 2000 SIAM PublicationsAn exact algorithm is proposed for minimum sum-of-squares nonhierarchical clustering, i.e., for partitioning a given set of points from a Euclidean m-space into a given number of clusters in order to minimize the sum of squared distances from all points to the centroid of the cluster to which they belong. This problem is expressed as a constrained hyperbolic program in 0-1 variables. The resolution method combines an interior point algorithm, i.e., a weighted analytic center column generation method, with branch-and-bound. The auxiliary problem of determining the entering column (i.e., the oracle) is an unconstrained hyperbolic program in 0-1 variables with a quadratic numerator and linear denominator. It is solved through a sequence of unconstrained quadratic programs in 0-1 variables. To accelerate resolution, variable neighborhood search heuristics are used both to get a good initial solution and to solve quickly the auxiliary problem as long as global optimality is not reached. Estimated bounds for the dual variables are deduced from the heuristic solution and used in the resolution process as a trust region. Proved minimum sum-of-squares partitions are determined for the rst time for several fairly large data sets from the literature, including Fisher's 150 iris.This research was supported by the Fonds National de la Recherche Scientifique Suisse, NSERC-Canada, and FCAR-Quebec