Abstract
We address two two-dimensional bin packing problems where the bins are rectangular and have the same size. The items are also rectangular and all of them must be packed with the objective of minimizing the number of bins. In the first problem, the two-stage problem, the items must be packed in levels. In the second problem, the restricted 3-stage problem, items can be grouped in stacks which are packed in levels. We propose a new decomposition model where subproblems are associated with the item that initializes a bin. The decomposition is solved by a heuristic which combines (perturbed) column generation, local search, beam branch-and-price, and the use of a general purpose mixed integer programming solver. This approach is closely related with SearchCol, a framework for solving integer programming / combinatorial optimization decomposition models. Computational results with 500 instances from the literature show that the proposed hybrid heuristic is efficient in obtaining high quality solutions. It uses more 8 and 17 bins than the 7364 and 7340 bins of a compact model from the literature for the 2 and 3-stage problems, respectively, while the sum of the time spent for all instances is 35% and 58% of the time spent by the compact model.

Abstract
Although the importance of the social, economic, environmental and traditional importance of artisanal fisheries is widely accepted, there is no single internationally accepted definition for this activity, since its characteristics differ among countries. Notwithstanding, it is also generally accepted that artisanal fisheries comprises a group of characteristics that clearly differ from those of the industrial fishing. In the present paper, an objective, simple and easy to use methodology is presented for the segmentation of fishing fleets by using a group of descriptors currently available in the European Union datasets. The numerical descriptors approach (NDA) is a score-based methodology that was applied to several EU fishing fleets from the Atlantic Area. The results obtained allow a more realistic segmentation of the European fishing fleet into artisanal (both coastal artisanal and small-scale fisheries) and non-artisanal than the current limit of 12 m vessels overall length. The procedure can be, and should be, refined and improved by the addition of new descriptors (e.g. operational range of the vessels and fishing effort, time spent at sea as well as other socio-economic indicators) when the necessary information becomes available for the entire European fishing fleet. The NDA represents a flexible tool that could be used at any geographical scale by adapting the final score and/or the numerical ranges of each descriptor.

Abstract
Pressure fiber sensors play an important role in downhole high pressure measurements to withstand long term operation. The purpose of this paper is to present an application of hollow core photonic crystal fiber (HC-PCF) as a high pressure sensor head for downhole application based on dispersion variation. We used a high pressure stainless steel unit to exert pressure on the sensor. The experimental results show that different wavelengths based on sagnac loop interferometer have additive sensitivities from 5 x 10(-5) nm/psi at 1480 nm to 1.3 x 10(-3) nm/psi at 1680 nm. We developed a simulation to understand the reason for difference in sensitivity of wavelengths and also the relationship between deformation of HC-PCF and dispersion variation under pressure. For this purpose, by using the finite element method, we investigated the effect of structural variation of HC-PCF on spectral transformation of two linear polarizations under 1000 psi pressure. The simulation and experimental results show exponential decay behavior of dispersion variation from -3.4 x 10(-6) 1/psi to -1.3 x 10(- 6) 1/psi and from -5 x 10(-6) 1/psi to -1.8 x 10(-6) 1/psi, respectively, which were in a good accordance with each other. (C) 2014 AIP Publishing LLC.

Abstract
As a crucial factor in global energy consumption, environmental problems related to the greenhouse gas emissions and high oil prices have motivated the growth and incorporation of alternative sources of energy into power systems. However, one of the most important facets of such problems is their intermittent nature, which means that the operation and management of a power system is a difficult task. In this paper, a probabilistic approach to solving the economic dispatch (ED) problem under conditions of uncertainty is presented. The proposed methodology allows for obtaining the probability distribution function (PDF) of all generation units, the energy not supplied (ENS) and the total generation cost. A case study based on an insular power system is analyzed, with reference to the important relationship that exists between the PDF of net load demand and the PDF of ENS, power production and total generation cost.

Abstract
Recommender systems (RS) are increasingly adopted by e-business, social networks and many other user-centric websites. Based on the user's previous choices or interests, a RS suggests new items in which the user might be interested. With constant changes in user behavior, the quality of a RS may decrease over time. Therefore, we need to monitor the performance of the RS, giving timely information to management, who can than manage the RS to maximize results. Our work consists in creating a monitoring platform - based on Business Intelligence (BI) and On-line Analytical Processing (OLAP) tools - that provides information about the recommender system, in order to assess its quality, the impact it has on users and their adherence to the recommendations. We present a case study with Palco Principal(1), a social network for music.

Abstract
In this work we present a new low cost SPR (Surface Plasmon Resonance) sensor configuration based on efficient higher-order mode filtering in plastic multimode fibers, using a tapered POF (Plastic Optical Fiber) after the sensor system, without decreasing the sensitivity of the sensor. In particular, we present the experimental results obtained with this new configuration. The experimental results have shown as the tapered POF after the sensor system influences the performances in terms of refractive index range and Signal-to-Noise Ratio (SNR).