In recent years, many systems for visualizing and exploring massive amounts of data have emerged. A topic that has not yet been investigated much concerns the visualization and exploration of constraints between objects such as relationships of joint contribution to a set or mutual exclusion. In this paper, we present concepts toward visualizing mutual constraints in the well-known game of Sudo...

This paper describes components of a branch-and-cut algorithm for solving integer linear programs having a large symmetry group. It describes an isomorphism pruning algorithm and variable setting procedures using orbits of the symmetry group. Pruning and orbit computations are performed by backtracking procedures using a Schreier-Sims table for representing the symmetry group. Applications to h...

We study on-line models for the set-covering problem in which items from a ground set arrive one by one and with any such item c, the list of names of sets that contain it in the final instance is also presented possibly together with some information regarding the content of such sets. A decision maker has to select which set, among the sets containing c, has to be put in the solution in order...

In the oil industry, different oil components are blended in a refinery to fuel products. These products are transported to different harbors by ship. Due to the limited storage capacity at the harbors and the undesirability of a stock-out, inventory levels at the harbors have to be taken into account during the construction of the ship routes. In this paper, we give a detailed description of t...

|This paper presents a simulation-based approach to automatic test-frequency generation of linear analog circuits considering parameter variations. It consists of two steps. First, a candidate set of frequencies|each detects robustly some faults|is generated by a concurrent and lazy fault simulationmethod. Next, the minimum number of test frequencies to detect all the possible faults is selecte...

In this work, we present a single unified framework that can solve many geometric covering queries such as inspection and mold-design. The suggested framework reduces a geometric covering query to the classic computer science set-covering problem. The solution is of exponential complexity due to the inherent complexity of the classic set-covering problem. However, in practice, we are able to ef...

Problem Statement Airlines daily face the problem of how to recover when a crew's schedule is disrupted by unplanned events such as maintenance problems or severe weather conditions. These problems create a domino effect and several flights may be delayed or canceled, and aircraft and crews may miss the rest of their assigned flights. Airline coordinators then have to find a minimal cost reassi...

We consider a scenario where stops are to be placed along an already existing public transportation network in order to improve its attractiveness for the customers. The core problem is a geometric set covering problem which is NP-hard in general. However, if the corresponding covering matrix has the consecutive ones property, it is solvable in polynomial time. In this paper, we present data re...

The set k-covering problem is a variant of the classical set covering problem, in which each object is required to be covered at least k times. We describe a hybrid Lagrangean heuristic, named LAGRASP, which combines subgradient optimization and GRASP with path-relinking to solve the set kcovering problem. Computational experiments carried out on 135 test instances show experimentally that by p...

A genetic algorithm (GA) for the set covering problem is developed using a non-binary solution representation. The paper describes the GA and the new problem-speciic operators of crossover and local improvement that we have implemented in it. Usage of these operators leads to a substantial improvement of the algorithm. Finally, some promising results of computation experiment and comparison to ...