We investigate the statistical properties of cut sizes generated by heuristic algorithms which solve the graph bisection problem approximately. On an ensemble of sparse random graphs, we find empirically that the distribution of the cut sizes found by “local” algorithms becomes peaked as the number of vertices in the graphs becomes large. Evidence is given that this distribution tends toward a ...

OBJECTIVES To study whether fine-cut tobacco poses a problem for public health and consumer affairs. METHODS We analyzed up to 70% of the fine-cut tobacco market in Spain. Regarding public health, the contents of nicotine, tar and carbon monoxide were analyzed and compared with levels in conventional cigarettes. Concerning consumer affairs, the labeling of samples was checked. RESULTS The c...

In this paper the problem of finding the sparsest (i.e., minimum cardinality) critical k-tuple including one arbitrarily specified measurement is considered. The solution to this problem can be used to identify weak points in the measurement set, or aid the placement of new meters. The critical k-tuple problem is a combinatorial generalization of the critical measurement calculation problem. Us...

We present two exact algorithms based on Benders decomposition for solving the multicommodity uncapacitated fixed-charge network design problem. The first implements Benders decomposition within a branch-and-cut framework. We present implementation techniques crucial for the algorithm's efficiency such as cut selection criteria and core point definition and highlight their impact on the solutio...

We revisit the double digest problem, which occurs in sequencing of large DNA strings and consists of reconstructing the relative positions of cut sites from two different enzymes: we rst show that double digest is strongly NP-complete, improving previous results that only showed weak NP-completeness. Even the (experimentally more meaningful) variation in which we disallow coincident cut sites ...

Unless the widely believed P 6= NP conjecture is false, there is no polynomial algorithm that can solve all instances of an NP-hard problem. Thus, when faced with an NP-hard problem (such as the Max-Cut problem discussed below) one has three options: to use an exponential type algorithm that solves exactly the problem in all instances, to design polynomial time algorithms that only work for som...

This paper presents a method for optimizing the machining parameters in rough turning processes to control the vibrations and deformations and minimize the production time per component under practical constraints. The optimization model is formulated, in which piecewise constraints are introduced based on the varying length-to-diameter (L/D ) ratio of the workpiece. The optimization problem is...

We present in this paper several solutions to the challenging task of clustering software defect reports. Clustering defect reports can be very useful for prioritizing the testing effort and to better understand the nature of software defects. Despite some challenges with the language used and semi-structured nature of defect reports, our experiments on data collected from the open source proje...

This paper follows a word-document co-clustering model independently introduced in 2001 by several authors such as I.S. Dhillon, H. Zha and C. Ding. This model consists in creating a bipartite graph based on word frequencies in documents, and whose vertices are both documents and words. The created bipartite graph is then partitioned in a way that minimizes the normalized cut objective function...

This paper is concerned with the maximum cut problem in parallel on cubic graphs. New theoretical results characterizing the cardinality of the cut are presented. These results make it possible to design a simple combinatorial O(log n) time parallel algorithm , running on a CRCW PRAM with O(n) processors. The approximation ratio achieved by the algorithm is 1: 3 and improves the best known para...