Abstract
Two-dimensional irregular strip packing problems are cutting and packing problems where small pieces have to be cut from a larger object, involving a non-trivial handling of geometry. Increasingly sophisticated and complex heuristic approaches have been developed to address these problems but, despite the apparently good quality of the solutions, there is no guarantee of optimality. Therefore, mixed-integer linear programming (MIP) models started to be developed. However, these models are heavily limited by the complexity of the geometry handling algorithms needed for the piece non-overlapping constraints. This led to pieces simplifications to specialize the developed mathematical models. In this paper, to overcome these limitations, two robust MIP models are proposed. In the first model (DTM) the non-overlapping constraints are stated based on direct trigonometry, while in the second model (NFP - CM) pieces are first decomposed into convex parts and then the non-overlapping constraints are written based on nofit polygons of the convex parts. Both approaches are robust in terms of the type of geometries they can address, considering any kind of non-convex polygon with or without holes. They are also simpler to implement than previous models. This simplicity allowed to consider, for the first time, a variant of the models that deals with piece rotations. Computational experiments with benchmark instances show that NFP CM outperforms both DTM and the best exact model published in the literature. New real-world based instances with more complex geometries are proposed and used to verify the robustness of the new models.

Abstract

Abstract
Many of the 17 million Europeans who suffer from food allergies could benefit from a more direct information system in the identification of the 14 allergens regulated by the Parliament and Council Regulation (EU) no 1169/2011 in packages of food products. This study aimed at creating pictograms representing these 14 allergens along visual and tactile lines, through relief printing. Based on Inclusive Design approach, the project meant to overcome restrictions such as sight impairment or illiteracy. Making use of User Centered Design (UCD) methodology, and with the support of the SAED (Disabled Students Support Services of the University of Porto) and GAENEE-UP (Support Office for Students with Special Educational Needs of the University of Porto), it employed field observation processes, in which potential users recorded their tactile perception of basic elements of visual communication. The result is the creation of a universal code, which is meant to satisfy the expectations and needs of potential users, namely people with impaired sight.

Abstract
In the last few years, sustainability has become one of the priority lines for many companies and organizations, especially public administrations. This trend has been even more evident in some regions where the preservation of natural resources is of utmost importance, not only from an environmental perspective, but also from an economic one. In this context, technology has become one of the key factors to achieve sustainability goals. An example of these technologies are Unmanned Aerial Vehicles (UAVs) which are being used more and more with sustainability purposes. However, although some efforts have been made to propose software approaches to model sustainability, some examples that model the impact of technology on sustainability are still needed. This paper presents an instance of a sustainability metamodel for the UAVs domain. This model allows to specify the impact of UAV-based processes on sustainability, and also to identify potential limitations that may hinder its applicability. Finally, the paper provides some suggestions to complete the metamodel based on the instantiation process.

Abstract
The continuous process industry is currently facing a serious need for systems that allow to monitor and manage their factories. Despite the existing industrial visualization screens provide for a partial answer to the identified issue, there is a set of new technologies who might help on developing the existing industrial visualization systems and provide and improved aid to the human controllers who monitor and manage the production processes. The presented paper aims at not only delivering a serious and focused characterization on the existing industry visualization screens, but above all, it intends to present several opportunities, challenges and new perspectives for the use of innovative visualization technologies (such as 2.5D/3D screens, augmented and virtual reality) in those industries whose production process assumes itself as continuous. This contribute, from our perspective will serve as a basis for further research on the field.

Abstract
Purpose - This paper aims to address a mobile robot localization system that avoids using a dedicated laser scanner, making it possible to reduce implementation costs and the robot's size. The system has enough precision and robustness to meet the requirements of industrial environments. Design/methodology/approach - Using an algorithm for artificial beacon detection combined with a Kalman Filter and an outlier rejection method, it was possible to enhance the precision and robustness of the overall localization system. Findings - Usually, industrial automatic guide vehicles feature two kinds of lasers: one for navigation placed on top of the robot and another for obstacle detection (security lasers). Recently, security lasers extended their output data with obstacle distance (contours) and reflectivity. These new features made it possible to develop a novel localization system based on a security laser. Research limitations/implications - Once the proposed methodology is completely validated, in the future, a scheme for global localization and failure detection should be addressed. Practical implications - This paper presents a comparison between the presented approach and a commercial localization system for industry. The proposed algorithms were tested in an industrial application under realistic working conditions. Social implications - The presented methodology represents a gain in the effective cost of the mobile robot platform, as it discards the need for a dedicated laser for localization purposes. Originality/value - This paper presents a novel approach that benefits from the presence of a security laser on mobile robots (mandatory sensor when considering industrial applications), using it simultaneously with other sensors, not only to guarantee safety conditions during operation but also to locate the robot in the environment. This paper is also valuable because of the comparison made with a commercialized system, as well as the tests conducted in real industrial environments, which prove that the approach presented is suitable for working under these demanding conditions.