Optimization models for computer data storage design: An application

In this paper we discuss a model being used to optimize the system design of the Computer Centre of one of the most important Italian banking groups. Data and transactions, processed by the system, are grouped respectively in data sets and by type, so it is possible to deal with the large dimensions of the corresponding optimization models. The transactions' arrivals are considered as stochastic variables and their probability values are estimated on the base of theoretical considerations. The solutions for two optimization problems, constructed and solved for different scenarios, are discussed in detail.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/31307/1/0000215.pd

Optimal experimental design for combinatorial problems

We discuss two experimental designs and show how to use them to evaluate difficult empirical combinatorial problems. We restrict our analysis here to the knapsack problem but comment more generally on the use of computational testing to analyze the performances of algorithms.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44351/1/10614_2004_Article_BF00121637.pd

Clustering problems in optimization models

We discuss a variety of clustering problems arising in combinatorial applications and in classifying objects into homogenous groups. For each problem we discuss solution strategies that work well in practice. We also discuss the importance of careful modelling in clustering problems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44350/1/10614_2004_Article_BF00121636.pd

Toward a formal theory of model integration

The aim of this paper is to provide the first steps toward a formal theory of model integration. This is supported at least by three arguments: (a) increasing the productivity of the modeling work; (b) decreasing errors; (c) saving time and money. Of course, any formal theory has to be based on a given framework; in our case, we consider only models which satisfy the core concepts of Structured Modeling. The outline of the paper is as follows. After the motivations are pointed out, some preliminary results are given in section 2. Section 3 defines the levels of integration, while in sections 4 and 5 some examples are presented. Remarks and future extensions conclude the paper.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44247/1/10479_2005_Article_BF02032379.pd

Workshop on the satisfiability problem

This report contains abstracts and extended abstracts of talks presented at the Satisfiability Workshop at Certosa di Pontignano, Siena, Italy in April 28 - May 3, 199

Matchings in Colored Bipartite Networks

In K(n, n) with edges colored either red or blue, we show that the problem of finding a solution matching, a perfect matching consisting of exactly r red edges, and (n − r) blue edges for specified 0 ≤ r ≤ n, is a nontrivial integer program. We present an alternative, logically simpler proof of a theorem in [3] which establishes necessary and sufficient conditions for the existance of a solution matching and a new O(n 2.5) algorithm. This shows that the problem of finding an assignment of specified cost r in an assignment problem on the complete bipartite graph with a 0−1 cost matrix is efficiently solvable. Key words assignment problem, 0−1 cost matrix, extreme point with specified objective value. + Author for correspondence 1