Articles de revista
http://hdl.handle.net/2117/3406
2015-07-28T05:52:40ZInterdisciplinary Engineering Project: Experimental and Numerical Optimization of a Sandwich Panel
http://hdl.handle.net/2117/26541
Interdisciplinary Engineering Project: Experimental and Numerical Optimization of a Sandwich Panel
Roure Fernández, Francisco; Pastor Artigues, María Magdalena; Bonada Bo, Jordi; Rodero de Lamo, Lourdes
A teaching-learning experience focused on the promotion of specific transversal competencies (self-learning, efficient oral and written communication and team working) integrated into the curriculum of Bachelor in Industrial Engineering (BIE) is presented. With the aim of reinforcing some traditional lacking aspects in old engineering curricula, some core subjects
linked to project-based learning activities have been included in the new curriculum of BIE given by the School of
Engineering of Barcelona (UPC). The current curriculum includes two mandatory subjects aimed to the acquisition of
professional competencies. Students can choose from a list of fifteen available projects. An example of the type of projects
offered on the course is given here. It is an interdisciplinary project combining Mechanics of Materials, Statistics and Engineering Project disciplines. Teaching learning methodology and benefits of the approach followed for promoting professional skills are presented. The final section summarises the main results provided by the experience against conventional activities
2015-01-01T00:00:00ZLong-term sampling of dioxin-like substances from a clinker kiln stack using alternative fuels
http://hdl.handle.net/2117/23001
Long-term sampling of dioxin-like substances from a clinker kiln stack using alternative fuels
Rivera Austrui, Joan; Martínez, Karell; Marco Almagro, Lluís; Ábalos, Manuela; Abad, Esteban
The aim of this work is to characterize atmospheric emissions of polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs) and dioxin-like polychlorinated biphenyls (dl-PCBs) from a cement production plant where the existing clinker production line was completely replaced by a new state-of-the-art installation. The project started in April 2008 with the installation of a long-term sampling system in the stack of the clinker kiln that used petroleum coke as fuel; PCDD/PCDF and dl-PCB emissions were then evaluated for a two year period. To carry out the second part of the study, in 2010 the sampling system was moved to the new installation in which, apart from conventional fuel, recovered derived fuel (RDF) and WWTP sludge were used as alternative fuels. For both the old and new clinker kilns, PCDD/PCDF emission values were well below the limit established by the European Waste Incineration Directive 2000/76/CE (EWID) of 100 pg I-TEQ/Nm3; values ranged from 0.43 to 2.02 and from 0.07 to 3.31 pg I-TEQ/Nm3, respectively. dl-PCBs accounted for approximately 25% of the WHO-TEQ toxicity. These results prove that the installation is capable of reducing PCDD/PCDF and dl-PCB emissions when alternative fuels are integrated into the process.
In the case of PCDDs/PCDFs, the major contributions to total TEQ were usually from 2,3,7,8-TCDD (owing to its relative abundance) and 2,3,4,7,8-PeCDF (due to its high I-TEF of 0.5); while for dl-PCBs, the major contribution was from PCB-126. The slight shift in the congener profile between the old and new installations was characterized and a regression model was proposed for dl-PCB emissions depending on the RDF flow rate in the clinker.
2014-07-01T00:00:00ZOn left-truncating and mixing poisson distributions
http://hdl.handle.net/2117/22548
On left-truncating and mixing poisson distributions
Valero Baya, Jordi; Pérez Casany, Marta; Ginebra Molins, Josep
The distributions obtained by left-truncating at k a mixed Poisson distribution, kT-MP, and those obtained by mixing previously left-truncated Poisson distributions, M-kTP, are characterized by means of their probability generating function. The main consequence is that every kT-MP distribution is a M-kTP distribution, but not the other way around.
2014-02-01T00:00:00ZA competitive variable neighbourhood search algorithm for the blocking flow shop problem
http://hdl.handle.net/2117/22388
A competitive variable neighbourhood search algorithm for the blocking flow shop problem
Ribas Vila, Immaculada; Companys Pascual, Ramón; Tort-Martorell Llabrés, Xavier
2013-12-23T00:00:00ZLight consulting after design of experiments training: Lessons from a case study
http://hdl.handle.net/2117/22376
Light consulting after design of experiments training: Lessons from a case study
Marco Almagro, Lluís; Grima Cintas, Pedro; Tort-Martorell Llabrés, Xavier
We present a case study to show some positive and some problematic points regarding light consulting—when none of the parts is fully committed—on Design of Experiments (DOE). The situation is not unusual and frequently occurs after a DOE training course. In fact, the case used as an illustration occurred when advising a team of engineers from an aeronautical industrial company some months after giving them a 32-h DOE seminar. A key point is that, in spite of all the inconveniences and pitfalls, it may be a good alternative for the two parts, especially nowadays with all the internet facilities. The case study included in the paper serves as an excuse to give a set of recommendations on how to develop this light consulting approach the best possible way.
2014-04-01T00:00:00Z¿Es pi un impostor?
http://hdl.handle.net/2117/22352
¿Es pi un impostor?
Grima Cintas, Pedro
Parece que sobre p está todo dicho y que su papel protagonista en el reino de los números es indiscutible pero… ¿son posibles unas matemáticas en las que el número pi no tenga un papel protagonista, en las que 3,14159… suene a número raro que no sugiere nada? Este artículo pretende poner de manifiesto que sí lo son, que el número pi no tiene la genuina especificidad de otros números singulares. Pero tranquilos, son las matemáticas de siempre, solo se trata repasar los terrenos en que aparece pi y descubrir que seguramente sería más justo que el número singular fuera otro.
2012-07-01T00:00:00ZThe time has come: Statistics in bestselling books
http://hdl.handle.net/2117/21021
The time has come: Statistics in bestselling books
Grima Cintas, Pedro; Marco Almagro, Lluís
Beyond textbooks, statistics is also present in bestselling books, those
that appear on the top 10 lists of bookshops and online bookstores. This
paper discusses five of those books, highlighting the role of statistics in
each one. Besides describing the general topics of the books, we want to
show that the knowledge of the world around us – and also the knowledge
on ourselves – advances thanks to the application of the scientific method
of which statistics is a key element. The paper finishes with some thoughts
on the desirability of a practical approach to teaching statistics
2013-10-01T00:00:00ZA Cluster analysis of vote transitions
http://hdl.handle.net/2117/20843
A Cluster analysis of vote transitions
Puig Oriol, Xavier; Ginebra Molins, Josep
To help settle the debate triggered the day after any election around the origin and destination of the vote of winners and losers, a Bayesian analysis of the results in a pair of consecutive elections is proposed. It is based on a model that simultaneously carries out a cluster analysis of the areas in which the results are broken into and links the results in the two elections of areas in a given cluster through a vote switch matrix. The number of clusters is chosen both through predictive checks as well as by testing whether the residuals are spatially correlated or not. The analysis is tried on the results in Barcelona of a pair of consecutive elections held just four months apart, in 2003 for the Catalan parliament and in 2004 for the Spanish parliament. The proposed approach, which reconstructs individual behavior from aggregated data, can be exported to be a solution for any ecological inference problem where one cannot assume that all the areas are exchangeable the way typically assumed by other ecological inference methods.
Bayesian model checking;
Bayesian hierarchical model;
Ecological inference;
Election data;
Spatial data
2014-01-01T00:00:00ZOn poisson-stopped-sums that are mixed poisson
http://hdl.handle.net/2117/19966
On poisson-stopped-sums that are mixed poisson
Valero Baya, Jordi; Pérez Casany, Marta; Ginebra Molins, Josep
Maceda (1948) characterized the mixed Poisson distributions that are Poisson-stopped-sum distributions based on the mixing distribution. In an alternative characterization of the same set of distributions here the Poisson-stopped-sum distributions that are mixed Poisson distributions is proved to be the set of Poisson-stopped-sums of either a mixture of zero-truncated Poisson distributions or a zero-modification of it.
2013-01-01T00:00:00ZAn efficient iterated local search algorithm for the total tardiness blocking flow shop problem
http://hdl.handle.net/2117/19622
An efficient iterated local search algorithm for the total tardiness blocking flow shop problem
Ribas Vila, Immaculada; Companys Pascual, Ramón; Tort-Martorell Llabrés, Xavier
This paper deals with the blocking flow shop problem and proposes an Iterated Local Search (ILS) procedure combined with a variable neighbourhood search (VNS) for the total tardiness minimisation. The proposed ILS makes use of a NEH-based procedure to generate the initial solution, and uses a local search to intensify the exploration that combines the insertion and swap neighbourhood and uses a perturbation mechanism consisting of three neighbourhood operators to diversify the search. The computational evaluation has shown the effectiveness of combining the insertion and swap neighbourhood during the search despite the insertion neighbourhood being more effective than the swap neighbourhood for this problem. Finally, the computation of this algorithm when evaluated against two other algorithms from the literature shows good performance.
2013-04-27T00:00:00Z