In mathematical/statistical modeling of complex systems, the locations of the data points are essential to the success of the algorithm. Sequential design methods are iterative algorithms that use data acquired from previous iterations to guide future sample selection. They are often used to improve an initial design such as a Latin hypercube or a simple grid, in order to focus on highly dynamic parts of the design space. In this paper, a comparison is made between different sequential design methods for global surrogate modeling on a real-world electronics problem. Existing exploitation and exploration-based methods are compared against a novel hybrid technique which incorporates both an exploitation criterion, using local linear approximations of the objective function, and an exploration criterion, using a Monte Carlo Voronoi tessellation. The test results indicate that a considerable improvement of the average model accuracy can be achieved by using this new approach.

This paper analyses challenges and opportunities for improving energy efficiency in small and medium enterprises (SMEs) by reviewing research design and results out of seven European projects: SPEEDIER, SMEmPower Efficiency, E2Driver, Innoveas, Triple-A, DEESME and ICCEE. These projects aim to improve SMEs’ awareness of energy efficiency and support an effective decision-making-oriented approach to it. Drivers and barriers to energy efficiency improvements in European SMEs of various industrial sectors have been investigated by means of surveys, focused group discussions and interviews. A meta-analysis of the results of the seven EU projects was carried out to discover trends related to energy efficiency in European SMEs; this was supported by the use of a unifying analytic framework that enabled merging and cross-validation of the findings of the seven projects. The analysis indicated, by means of new data collected by the seven projects, that staff training, facilitation of energy audits, development of corporate policy measures and collaboration between SMEs involved in the same supply chain are key mechanisms to improve the uptake of energy efficiency measures in SMEs which has significant potential to achieve higher energy savings and energy cost reductions.