Abstract
This special issue contains a selection of the best papers presented at the XI Iberoamerican Workshop on Requirements Engineering and Software Environments (IDEAS'08), that was held in Recife, Pernambuco, Brazil, on 11-15 February 2008. The papers included here provide some good examples of the research being currently conducted in Iberoamerica, Spain and Portugal in the context of Software Enginerering and Requirements Engineering.

Abstract
This paper enhances cost efficiency measurement methods to account for situations where the input prices can depend on negotiation or tend to qualitatively differentiate the resources available at each decision making unit. In these circumstances, there are some shortcomings in the cost efficiency measure described in the data envelopment analysis (DEA) literature. This paper proposes new models and measures for cost efficiency evaluation that overcome the limitations of the existing DEA models. The applicability of the measures developed is illustrated in the context of the analysis of bank branch performance.

Abstract
In this article we present a practical example where the concept of Holistic Metrics (Feliz-Teixeira & Brito, 2006) is used as a way for sensing the results obtained in a simulation study related to the Portuguese enterprise GalpEnergia. Previously described in Feliz-Teixeira & Brito (2005), that case is used again in this article in order to demonstrate the practical value of the Holistic Metrics concept. This is basically a simple method for estimating or characterizing the behaviour of complex systems, in particular when these are studied throughout simulation. Instead of treating the complex output data obtained from this kind of system along the time domain, this perspective encourages analysts to represent such data in the frequency domain, somewhat as is adopted in Fourier Analysis and in Quantum Mechanics.

Abstract
This work aims to determine the effect of performing age based preventive maintenance actions on a repairable system with a constant failure rate. Periodic overhauls are carried out every time the system reaches the end of a constant time interval without failures and the system is repaired whenever a failure occurs. Performing overhauls implies interventions such as: replacement of parts with increasing hazard rate, cleaning, oiling etc. In this work, the relationship between the initial failure rate (without periodic overhauls) and the failure rate with periodic overhauls is established. © 2008 ICQR.

Abstract
In production planning in the glass container industry, machine-dependent setup times and costs are incurred for switch overs from one product to another. The resulting multi-item capacitated lot-sizing problem has sequence-dependent setup times and costs. We present two novel linear mixed-integer programming formulations for this problem, incorporating all the necessary features of setup carryovers. The compact formulation has polynomially many constraints, whereas the stronger formulation uses an exponential number of constraints that can be separated in polynomial time. We also present a five-step heuristic that is effective both in finding a feasible solution (even for tightly capacitated instances) and in producing good solutions to these problems. We report computational experiments.

Abstract