Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3920
2015-07-28T04:07:55ZA fault detection method for pitch actuators faults in wind turbines
http://hdl.handle.net/2117/28434
A fault detection method for pitch actuators faults in wind turbines
Tutivén Gálvez, Christian; Vidal Seguí, Yolanda; Acho Zuppa, Leonardo; Rodellar Benedé, José
The paper presents a model-based fault detection method for pitch actuators faults using the normalized gradient method to estimate the parameters of the pitch actuator. One major difficulty is that the input signal to the parametric estimation method must be a persistent excitation. To circumvent this, a chattering term
is added to the pitch control law and the usual low-pass filters are not used for the parametrization in the normalized gradient
method (thus acceleration information is used). In order to verify the proposed method, simulations are conducted within a Hardware in the Loop (HiL) platform using the wind turbine simulation software
FAST (Fatigue, Aerodynamics, Structures, and Turbulence).
2015-01-01T00:00:00ZEvaluating an E-portfolio for a linear algebra course using rubrics
http://hdl.handle.net/2117/28385
Evaluating an E-portfolio for a linear algebra course using rubrics
García Planas, María Isabel; Taberna Torres, Judit; Domínguez García, Santiago; Palau, Ramon
There is always a need to evaluate training skills acquired for, in this way, to know whether they have
achieved the learning objectives. The use of the e-portfolio becomes more common among teachers
then, becomes increasingly necessary define a good evaluation system. E-Portfolio evaluation criteria
should take into account operational, appearance, evidence and reflection indicators. Considering all
these aspects and to respond to such needs is chosen to create a rubric to assess. Remember that
scoring rubrics are descriptive scoring schemes that are developed by teachers or other evaluators to
guide the analysis of the products or processes of students’ efforts.
In creating the rubric, first we analyzed what the analytical evaluation criteria to be considered for a
course in linear algebra of first year engineering degree and taking into account the skill sets required
to demonstrate that they have acquired the skills set by the University in the course to evaluate. In so
far as a mathematics course, we must not forget the following levels of quality corresponding to
Solving, Reasoning and Proof, Communication, Connections, and Representation, from excellent to
poor, for a specific assignment.
For the specific subject of linear algebra of the first year of Engineering at the ETSEIB of Polytechnic
University of Catalonian, two rubrics are proposed, the first one for the student self-assessment as
well as for peer assessment, and the second one for the assessment of student work from the
teacher. The rubric to evaluate students' work consists of 3 sub-rubrics, one to analyze the formal part
of the portfolio of the student (structure, spelling, level of language, among others) and the other two
for evaluating projects that students must perform.
2009-01-01T00:00:00ZUsing the e-portfolio for large groups of students
http://hdl.handle.net/2117/28384
Using the e-portfolio for large groups of students
García Planas, María Isabel; Taberna Torres, Judit; Domínguez García, Santiago; Palau, Ramon
The number of students in class in studies of first year engineering degree in many Universities, in particular at the Polytechnic University of Catalonia, is high with an average of 75 students per class.
While the large groups permit to transmit information efficiently, to a large number of students, it is equally true that it is difficult to teach students to actively think about what they are learning.
In small groups is becoming more common the use of e-portfolio for learning and assessment. This increased use is due to the need of the teacher to improve student autonomy by means reflection on
learning processes. The biggest growth is in the use of e-portfolio as it has the ability to incorporate new information and communication technologies into the learning process.
We think and we are convinced that teaching in large groups does not have to limit itself to the master class only. Under this conviction we have introduced the e-portfolio in a core subject in studies of first
year engineering degree. Also they can be displayed in a common space on University virtual campus where the students can view each other’s e-portfolios.
In this work, we show the results concerning the use of the e-portfolio in large groups as a tool for teaching, learning, assessment and self-assessment of student learning, as well as and satisfaction
and usefulness of this tool. The study sample consists of all students from the first year of Engineering in the subject of linear algebra at the ETSEIB of Polytechnic University of Catalonian.
To prepare the e-portfolio has been essential on the one hand, the definition of the goals that we want students to achieve, as well as the issues that we consider basic to exceed targets, also we must
prepare and plan the course comprehensively in order to make the coordination of the different tasks carried out in the classroom with the work of the e-portfolio. On the other hand, has been important the
selection of platforms to implement the e-portfolio. We decided to choose the use of the integrated Moodle and Mahara (Mahoodle) platform, as well as the simultaneous use of platforms Exabis inside
Moodle and Google Sites.
2015-01-01T00:00:00ZDifferential flatness of a class of n—DOF planar manipulators driven by an arbitrary number of actuators
http://hdl.handle.net/2117/28316
Differential flatness of a class of n—DOF planar manipulators driven by an arbitrary number of actuators
Franch Bullich, Jaume; Reyes Jimenez, Alejandro; Agrawal, Sunil K.
This paper deals with the problem of feedback
linearization, either by dynamic or static feedback, of a planar robot manipulator with n links and m inputs. The robot is pro-vided with a particular inertia distribution in order to reduce nonlinearities, and with n-m springs to keep controllability.
Under these design conditions, the paper answers the question of where to place the actuators such that the system is static feedback linearizable. For those systems that there are not static feedback linearizable, the paper shows that are linearizable by prolongations and, therefore, dynamic feedback linearizable.
2013-01-01T00:00:00ZCharacterization of coastal upwelling events during the generation of the water column stratification in spring (Vilanova i la Geltrú, NW Mediterranean)
http://hdl.handle.net/2117/28297
Characterization of coastal upwelling events during the generation of the water column stratification in spring (Vilanova i la Geltrú, NW Mediterranean)
Antonijuan Rull, Josefina; Guillem, Jorge; Simarro, Gonzalo; Nogueras Cervera, Marc; Río Fernandez, Joaquín del
This article presents some preliminary results on the characterization of inputs of offshore waters (upwelling events) in the coast off Vilanova i la Geltrú (NW Mediterranean) in the spring of the years 2010, 2012 and 2014. The upwelling events are studied in terms of meteorological and oceanographic conditions
2015-01-01T00:00:00ZAnálisis de datos y clasificación del sector del autobús interurbano en Catalunya
http://hdl.handle.net/2117/28277
Análisis de datos y clasificación del sector del autobús interurbano en Catalunya
Burgos Campos, Fèlix; Pérez Foguet, Agustí
2008-01-01T00:00:00ZA note on multinomial (probabilistic) values
http://hdl.handle.net/2117/28244
A note on multinomial (probabilistic) values
Domènech Blázquez, Margarita; Giménez Pradales, José Miguel; Puente del Campo, María Albina
The work tries to contribute to a better understanding of multinomial values as a consistent alternative or complement to classical values (Shapley and Banzhaf). We compare the behavior of multinomial values with respect several standard properties for values and power indices, including marginal contributions, balanced contributions, desirability relation and null player exclusion property.
2015-01-01T00:00:00ZOn computing flat outputs through Goursat normal form
http://hdl.handle.net/2117/27990
On computing flat outputs through Goursat normal form
Franch Bullich, Jaume; Manzanera, Ana; Valero, Gemma
This paper is devoted to computation of flat outputs by means of the Goursat normal form of the Pfaffian system associated to any control system in state space form. The algorithm explained here consists in three steps: i) Transformation of the system into its Pfaffian equivalent. ii) Computation of the Goursat normal form for the Pfaffian system. iii) Rewriting of the state space equations in the new variables. At this stage, a feedback law simplifies the equations and, therefore, the flat outputs can be easily computed. As an example, the algorithm is applied to a system consisting in a car with expanding wheels. Point to point trajectories are obtained thanks to the property of differential flatness. The paper also includes a control law that minimizes errors in the initial conditions.
2014-01-01T00:00:00ZA methodology to assess ionospheric models for GNSS
http://hdl.handle.net/2117/27981
A methodology to assess ionospheric models for GNSS
Rovira Garcia, Adrià; Juan Zornoza, José Miguel; Sanz Subirana, Jaume; González Casado, Guillermo; Ibáñez Segura, Marcos - Deimos
2015-01-01T00:00:00ZNovel ionospheric activity indicator specifically tailored for GNSS users
http://hdl.handle.net/2117/27928
Novel ionospheric activity indicator specifically tailored for GNSS users
Sanz Subirana, Jaume; Juan Zornoza, José Miguel; González Casado, Guillermo; Prieto Cerdeira, Roberto; Schlüter, S.; Orús Pérez, Raul
This work introduces a novel ionospheric activity indicator useful for identifying disturbed periods affecting performance for GNSS users, at regional level. This indicator is based in the “Along Arc TEC Rate (AATR) and can be easily computed from GNSS data. The AATR indicator has been assessed over more than one Solar Cycle (2002-2013) involving 140 receivers distributed world-wide. Results show that it is well correlated with the ionospheric activity and, unlike other global indicators linked to the geomagnetic activity (i.e. DST, Ap), it is sensitive to regional behaviour the ionosphere and identifies specific effects on GNSS users. Moreover from a devoted analysis of EGNOS performances in different ionospheric conditions, it follows that the AATR indicator is able to predict SBAS user availability anomalies linked to the ionosphere. The AATR indicator has been chosen as the metric to characterise the ionosphere operational conditions in the frame of EGNOS activities. This indicator has been also proposed for joint analysis in the International SBAS-Ionosphere Working Group.
2014-01-01T00:00:00Z