Cristina Manchado

Elitist clonal selection algorithm for optimal choice of free knots in B-spline data fitting

Graphical abstractDisplay Omitted HighlightsIn this paper we introduce an adapted elitist clonal selection algorithm for automatic knot adjustment of B-spline curves.Our method determines the number and location of knots automatically in order to obtain an extremely accurate fitting of data.In addition, our method minimizes the number of parameters required for this task.Our approach performs very well and in a fully automatic way even for the cases of underlying functions requiring identical multiple knots, such as functions with discontinuities and cusps.Our experimental results show that our approach outperforms previous approaches in terms of accuracy and flexibility. Data fitting with B-splines is a challenging problem in reverse engineering for CAD/CAM, virtual reality, data visualization, and many other fields. It is well-known that the fitting improves greatly if knots are considered as free variables. This leads, however, to a very difficult multimodal and multivariate continuous nonlinear optimization problem, the so-called knot adjustment problem. In this context, the present paper introduces an adapted elitist clonal selection algorithm for automatic knot adjustment of B-spline curves. Given a set of noisy data points, our method determines the number and location of knots automatically in order to obtain an extremely accurate fitting of data. In addition, our method minimizes the number of parameters required for this task. Our approach performs very well and in a fully automatic way even for the cases of underlying functions requiring identical multiple knots, such as functions with discontinuities and cusps. To evaluate its performance, it has been applied to three challenging test functions, and results have been compared with those from other alternative methods based on AIS and genetic algorithms. Our experimental results show that our proposal outperforms previous approaches in terms of accuracy and flexibility. Some other issues such as the parameter tuning, the complexity of the algorithm, and the CPU runtime are also discussed.

Information management and improvement of citation indices

Bibliographic databases lack uniformity and accuracy due to duplications, misspellings, name variants, etc.Dataset pre-processing is very important to obtain more accurate, realistic and valid bibliometric analysis.STICCI.eu is a software tool for improving and converting citation indices - enhancing uniformity.STICCI.eu is able to convert bibliographical citation formats (WoS, Scopus, Google Scholar, CSV, BibTex, RIS).It corrects mistakes in databases, detecting duplications, misspellings, name variants, toponymical names, etc. Bibliometrics and citation analysis have become important sets of methods for library and information science, as well as exceptional sources of information and knowledge for many other areas. Their main sources are citation indices, which are bibliographic databases like Web of Science, Scopus, Google Scholar, etc. However, bibliographical databases lack perfection and standardization. There are several software tools that perform useful information management and bibliometric analysis importing data from them. A comparison has been carried out to identify which of them perform certain pre-processing tasks. Usually, they are not strong enough to detect all the duplications, mistakes, misspellings and variant names, leaving to the user the tedious and time-consuming task of correcting the data. Furthermore, some of them do not import datasets from different citation indices, but mainly from Web of Science (WoS).A new software tool, called STICCI.eu (Software Tool for Improving and Converting Citation Indices - enhancing uniformity), which is freely available online, has been created to solve these problems. STICCI.eu is able to do conversions between bibliographical citation formats (WoS, Scopus, CSV, BibTex, RIS), correct the usual mistakes appearing in those databases, detect duplications, misspellings, etc., identify and transform the full or abbreviated titles of the journals, homogenize toponymical names of countries and relevant cities or regions and list the processed data in terms of the most cited authors, journals, references, etc.

Novel Technique for Obtaining Double-Layer Tensegrity Grids

Double-layer tensegrity grids (DLTGs) may be defined as tensegrity spatial systems containing two parallel horizontal networks of members in tension forming the top and bottom layers, whose nodes are linked by vertical and/or inclined bracing members in compression and/or tension. In this paper, a new approach is described. Conventional double-layer grids (DLGs) are composed of three layers: top, bottom and bracing members. This paper shows new rules for generating original DLGs following a recent methodology for their composition, from the mosaic of the bracing members and additional laws. Finally, from them, a new technique, known as Rot-Umbela manipulation, is applied to obtain their tensegrity form, opening and endless catalogue of DLTGs.

Innovative Families Of Double-Layer Tensegrity Grids: Quastruts and Sixstruts

AbstractDouble-layer tensegrity grids (DLTGs) are spatial reticulated systems based on tensegrity principles, which have been studied in detail over recent years. The most important investigations have been carried out focusing on a short list of tensegrity grids. This paper explains, using real examples, how to use Rot-Umbela manipulations, a unique technique developed for generating innovative typologies of tensegrity structures. It is applied to two already existing tensegrity grids to obtain two new DLTGs. Their analysis permits us to identify, inside these novel grids, the modules that compose them, which were unknown until now. A brief description of these components and some information about their static analysis, for example states of self-stress and internal mechanisms, is provided. These novel modules belong to a family, all of them with similar characteristics in terms of geometry and topology, and can be used to generate a wide catalog of DLTGs. Some examples of new grids are presented, descr...

Generation and Nomenclature of Tessellations and Double-Layer Grids

AbstractThe aim of this work is to establish a systematic methodology for generating automatically different tessellations and double-layer grids (DLGs) following a newly defined, specific nomenclature. This particular nomenclature defines the notation of mosaics and DLGs in a synthesized and unique manner, and can generate and design them after the parameters expressed in their own names. By means of an algorithm and some computational codes, it is possible to recreate in 3D any DLGs directly from their own names. The current nomenclature for tessellations is also analyzed and found to have severe disadvantages, such as the excessive length of their notations and their nonunique character. A new nomenclature is proposed to define and generate n-uniform mosaics consistently and unequivocally in a manner consistent with the current nomenclature used for Archimedean (regular and semiregular) tessellations.

Symmetry in Regular Polyhedra Seen as 2D Möbius Transformations: Geodesic and Panel Domes Arising from 2D Diagrams

This paper shows a methodology for reducing the complex design process of space structures to an adequate selection of points lying on a plane. This procedure can be directly implemented in a bi-dimensional plane when we substitute (i) Euclidean geometry by bi-dimensional projection of the elliptic geometry and (ii) rotations/symmetries on the sphere by Mobius transformations on the plane. These graphs can be obtained by sites, specific points obtained by homological transformations in the inversive plane, following the analogous procedure defined previously in the three-dimensional space. From the sites, it is possible to obtain different partitions of the plane, namely, power diagrams, Voronoi diagrams, or Delaunay triangulations. The first would generate geo-tangent structures on the sphere; the second, panel structures; and the third, lattice structures.

AMBEMAR-DSS: A Decision Support System for the Environmental Impact Assessment of Marine Renewable Energies

The high energy demand and the threat of climate change have led to a remarkable development of renewable energies, initially through technologies applied to the terrestrial environment and, recently, through the awakening of marine renewable energies. However, the development of these types of projects is often hampered by failure to pass the corresponding environmental impact assessment process. The complexity of working in the marine environment and the uncertainties associated with assessing the impacts of such projects make it difficult to carry out objective and precise environmental impact assessments. AMBEMAR-DSS seeks to establish a basis for understanding and agreement between the different stakeholders (project developers, public administrations, environmental organizations and the public in general), in order to find solutions that allow the development of marine renewable energies, minimizing their environmental cost. For this purpose, a DSS is proposed which, based on cartographic information and using objective and quantifiable criteria, allows comparative assessments and analyses between different project alternatives. The analytical procedures used by the system include, among others, hydrodynamic modeling tools and visual impact simulators. In addition, impacts on marine species are assessed taking into account intrinsic ecological and biological aspects. The magnitude of the impacts is quantified by means of fuzzy logic operations and the integration of all the elements is carried out by an interactive multi-criteria analysis. The results are shown in tables, graphs and figures of easy interpretation and can be also visualized geographically by means of a cartographic viewer. The system identifies the main impacts generated in the different phases of the project and allows establishing adequate mitigation measures in search of optimized solutions. The establishment of the assessment criteria has been based on the abundant, but dispersed, scientific literature on the various elements of the system and having the opinion of experts in the various fields. Nevertheless, the DSS developed constitutes a preliminary basis on which to build and improve a system with the input of researchers, promoters and experts from different disciplines.

Virtual reality to assess visual impact in wind energy projects

Virtual reality techniques have been used since several decades ago to complement the three dimensional modelling in engineering and other disciplines. This technology allows engineers to view their projects into a 3D environment helping to better understand the different designs and bringing a new perspective of them, and also to simulate different states of the construction process. When assessing the visual impact of a wind farm, the use of virtual reality scenery can help the designer to integrate the visual aspects in the planning process and to show the changes produced in the different views. Also, it is a very powerful communication tool that provides an effective way of presenting the visual impact, as well as to understand and imagine the future landscape for the stakeholders.

Gamification in a Graphical Engineering course - Learning by playing

Even though engineering is a vocational degree, students need to be stimulated so that they are more participative and active. New pedagogical methodologies have been proposed to inspire and motivate students while training to become professionals in the engineering field. One of them, gamification, is based on the use of game design elements in non-game contexts, like learning environments. Several studies have dealt with the use of gamification in engineering courses, 87% of them reporting that their implementation had some degree of positive outcome. This paper shows the experience of game-based learning applied to a Graphical Engineering course in the second year of the Mechanical Engineering curriculum at a Spanish university. Several activities were developed during the academic course, in which students had to face different kind of tasks: competitions, simulations, research tournaments, pokes, social forums, survey games, etc. As participation was voluntary in most cases, the current study is focused on the individual perception of the students, rather than on the overall learning outcomes of the group. The results of this experience based on “Learning by playing” have been positive, according to lecturers and students’ perception. The number of students considering the game-based activates as beneficial or entertaining is between 3 to 10 times higher than those who think the opposite. The main advantages of gamification have been, thus, increasing the attending ratio of the class, enhancing the interest for the topics of the lectures, bringing fun and joy to the classroom and giving more initiative to the students.

Teaching visual impact assessment at a master level

The purpose of this article is to describe a Master level subject on Visual Impact Assessment, presenting its most noteworthy contents, academic features, methodology, and technology. It also presents some practical results extracted from some outstanding final works submitted by the students during the academic year 2012–2013. These works can give a clear idea about the degree of achievement regarding competences and skills that students can achieve. As Visual Impact Assessment is a compulsory requirement in an Environmental Impact Assessment document, it needs to become incorporated in the professional curriculum and, therefore, needs to be taught in the classroom, for instance at an academic Master level. This paper describes a way to address it.