Ponències/Comunicacions de congressos
http://hdl.handle.net/2117/3974
2018-02-20T19:53:41ZReconciliando modularidad y eficiencia mediante atajos
http://hdl.handle.net/2117/114228
Reconciliando modularidad y eficiencia mediante atajos
Marco Gómez, Jordi; Franch Gutiérrez, Javier
Se presenta en este artículo una propuesta para el desarrollo de programas eficientes en el marco de la programación con tipos abstractos de datos (TAD), con el objetivo de respetar la estructura modular de los programas propia de este ámbito. La propuesta se centra en el concepto de atajo como camino eficiente de acceso a los datos, alternativo al acceso mediante las operaciones propias del TAD, y se desarrolla sobre un TAD concreto, el almacén de elementos. La definición de los atajos es altamente formal, mediante especificaciones algebraicas interpretadas con semántica inicial, de manera que el resultado tiene un significado bien definido y encaja sin problemas en el marco de la programación con TAD. La eficiencia se asegura mediante una implementación adecuada del tipo, que proporciona acceso constante a los datos siguiendo los atajos sin penalizar las otras operaciones del TAD. Se ilustra la utilidad de la propuesta mediante un ejemplo concreto.
2018-02-19T07:47:44ZMarco Gómez, JordiFranch Gutiérrez, JavierSe presenta en este artículo una propuesta para el desarrollo de programas eficientes en el marco de la programación con tipos abstractos de datos (TAD), con el objetivo de respetar la estructura modular de los programas propia de este ámbito. La propuesta se centra en el concepto de atajo como camino eficiente de acceso a los datos, alternativo al acceso mediante las operaciones propias del TAD, y se desarrolla sobre un TAD concreto, el almacén de elementos. La definición de los atajos es altamente formal, mediante especificaciones algebraicas interpretadas con semántica inicial, de manera que el resultado tiene un significado bien definido y encaja sin problemas en el marco de la programación con TAD. La eficiencia se asegura mediante una implementación adecuada del tipo, que proporciona acceso constante a los datos siguiendo los atajos sin penalizar las otras operaciones del TAD. Se ilustra la utilidad de la propuesta mediante un ejemplo concreto.Construct, merge, solve and adapt versus large neighborhood search for solving the multi-dimensional Knapsack problem: Which one works better when?
http://hdl.handle.net/2117/114023
Construct, merge, solve and adapt versus large neighborhood search for solving the multi-dimensional Knapsack problem: Which one works better when?
Lizárraga Olivas, Evelia; Blesa Aguilera, Maria Josep; Blum, Christian
Both, Construct, Merge, Solve and Adapt (CMSA) and Large Neighborhood Search (LNS), are hybrid algorithms that are based on iteratively solving sub-instances of the original problem instances, if possible, to optimality. This is done by reducing the search space of the tackled problem instance in algorithm-specific ways which differ from one technique to the other. In this paper we provide first experimental evidence for the intuition that, conditioned by the way in which the search space is reduced, LNS should generally work better than CMSA in the context of problems in which solutions are rather large, and the opposite is the case for problems in which solutions are rather small. The size of a solution is hereby measured by the number of components of which the solution is composed, in comparison to the total number of solution components. Experiments are conducted in the context of the multi-dimensional knapsack problem.
2018-02-12T09:29:45ZLizárraga Olivas, EveliaBlesa Aguilera, Maria JosepBlum, ChristianBoth, Construct, Merge, Solve and Adapt (CMSA) and Large Neighborhood Search (LNS), are hybrid algorithms that are based on iteratively solving sub-instances of the original problem instances, if possible, to optimality. This is done by reducing the search space of the tackled problem instance in algorithm-specific ways which differ from one technique to the other. In this paper we provide first experimental evidence for the intuition that, conditioned by the way in which the search space is reduced, LNS should generally work better than CMSA in the context of problems in which solutions are rather large, and the opposite is the case for problems in which solutions are rather small. The size of a solution is hereby measured by the number of components of which the solution is composed, in comparison to the total number of solution components. Experiments are conducted in the context of the multi-dimensional knapsack problem.A hybrid evolutionary algorithm based on solution merging for the longest arc-preserving common subsequence problem
http://hdl.handle.net/2117/114020
A hybrid evolutionary algorithm based on solution merging for the longest arc-preserving common subsequence problem
Blum, Christian; Blesa Aguilera, Maria Josep
The longest arc-preserving common subsequence problem is an NP-hard combinatorial optimization problem from the field of computational biology. This problem finds applications, in particular, in the comparison of art-annotated ribonucleic acid (RNA) sequences. In this work we propose a simple, hybrid evolutionary algorithm to tackle this problem. The most important feature of this algorithm concerns a crossover operator based on solution merging. In solution merging, two or more solutions to the problem are merged, and an exact technique is used to find the best solution within this union. It is experimentally shown that the proposed algorithm outperforms a heuristic from the literature.
2018-02-12T08:33:14ZBlum, ChristianBlesa Aguilera, Maria JosepThe longest arc-preserving common subsequence problem is an NP-hard combinatorial optimization problem from the field of computational biology. This problem finds applications, in particular, in the comparison of art-annotated ribonucleic acid (RNA) sequences. In this work we propose a simple, hybrid evolutionary algorithm to tackle this problem. The most important feature of this algorithm concerns a crossover operator based on solution merging. In solution merging, two or more solutions to the problem are merged, and an exact technique is used to find the best solution within this union. It is experimentally shown that the proposed algorithm outperforms a heuristic from the literature.An angel-daemon approach to assess the uncertainty in the power of a collectivity to act
http://hdl.handle.net/2117/114018
An angel-daemon approach to assess the uncertainty in the power of a collectivity to act
Fragnito, Giulia; Gabarró Vallès, Joaquim; Serna Iglesias, María José
We propose the use of the angel-daemon framework to assess the Coleman's power of a collectivity to act under uncertainty in weighted voting games.
In this framework uncertainty profiles describe the potential changes in the weights of a weighted game and fixes the spread of the weights' change. For each uncertainty profile a strategic angel-daemon game can be considered. This game has two selfish players, the angel and the daemon, the angel selects its action as to maximize the effect on the measure under consideration while daemon acts oppositely.
Players angel and daemon give a balance between the best and the worst. The angel-daemon games associated to the Coleman's power are zero-sum games and therefore the expected utilities of all the Nash equilibria
are the same. In this way we can asses the Coleman's power under uncertainty. Besides introducing the framework for this particular setting we analyse basic properties and make some computational complexity considerations. We provide several examples based in the evolution of the voting rules of the EU Council of Ministers.
The final publication is available at link.springer.com
2018-02-12T08:02:40ZFragnito, GiuliaGabarró Vallès, JoaquimSerna Iglesias, María JoséWe propose the use of the angel-daemon framework to assess the Coleman's power of a collectivity to act under uncertainty in weighted voting games.
In this framework uncertainty profiles describe the potential changes in the weights of a weighted game and fixes the spread of the weights' change. For each uncertainty profile a strategic angel-daemon game can be considered. This game has two selfish players, the angel and the daemon, the angel selects its action as to maximize the effect on the measure under consideration while daemon acts oppositely.
Players angel and daemon give a balance between the best and the worst. The angel-daemon games associated to the Coleman's power are zero-sum games and therefore the expected utilities of all the Nash equilibria
are the same. In this way we can asses the Coleman's power under uncertainty. Besides introducing the framework for this particular setting we analyse basic properties and make some computational complexity considerations. We provide several examples based in the evolution of the voting rules of the EU Council of Ministers.Parsing logical grammar: CatLog3
http://hdl.handle.net/2117/113964
Parsing logical grammar: CatLog3
Morrill, Glyn
CatLog3 is a Prolog parser/theorem-prover for (type) logical (categorial) grammar. In such logical grammar, grammar is reduced to logic: a string of words is grammatical if and only if an associated logical statement is a theorem. CalLog3 implements a logic extending displacement calculus, a sublinear fragment including as primitive connectives the continuous (Lambek) and discontinuous wrapping connectives of the displacement calculus, additives, 1st order quantifiers, normal modalities, bracket modalities and subexponentials. In this paper we survey how CatLog3 is implemented on the principles of Andreoli’s focusing and a generalisation of van Benthem’s
count-invariance.
2018-02-09T10:11:49ZMorrill, GlynCatLog3 is a Prolog parser/theorem-prover for (type) logical (categorial) grammar. In such logical grammar, grammar is reduced to logic: a string of words is grammatical if and only if an associated logical statement is a theorem. CalLog3 implements a logic extending displacement calculus, a sublinear fragment including as primitive connectives the continuous (Lambek) and discontinuous wrapping connectives of the displacement calculus, additives, 1st order quantifiers, normal modalities, bracket modalities and subexponentials. In this paper we survey how CatLog3 is implemented on the principles of Andreoli’s focusing and a generalisation of van Benthem’s
count-invariance.A polynomial-time algorithm for the Lambek calculus with brackets of bounded order
http://hdl.handle.net/2117/113963
A polynomial-time algorithm for the Lambek calculus with brackets of bounded order
Kanovich, Max; Kuznetsov, Stepan; Morrill, Glyn; Scedrov, Andre
Lambek calculus is a logical foundation of categorial grammar, a linguistic paradigm of grammar as logic and parsing as deduction. Pentus (2010) gave a polynomial-time algorithm for determining
provability of bounded depth formulas in L*, the Lambek calculus with empty antecedents allowed. Pentus’ algorithm is based on tabularisation of proof nets. Lambek calculus with brackets is a conservative extension of Lambek calculus with bracket modalities, suitable for the modeling of syntactical domains. In this paper we give an algorithm for provability in Lb*, the Lambek calculus with brackets allowing empty antecedents. Our algorithm runs in polynomial time when both the formula depth and the bracket nesting depth are bounded. It combines a Pentus-style tabularisation of proof nets with an automata-theoretic treatment of bracketing.
2018-02-09T09:57:17ZKanovich, MaxKuznetsov, StepanMorrill, GlynScedrov, AndreLambek calculus is a logical foundation of categorial grammar, a linguistic paradigm of grammar as logic and parsing as deduction. Pentus (2010) gave a polynomial-time algorithm for determining
provability of bounded depth formulas in L*, the Lambek calculus with empty antecedents allowed. Pentus’ algorithm is based on tabularisation of proof nets. Lambek calculus with brackets is a conservative extension of Lambek calculus with bracket modalities, suitable for the modeling of syntactical domains. In this paper we give an algorithm for provability in Lb*, the Lambek calculus with brackets allowing empty antecedents. Our algorithm runs in polynomial time when both the formula depth and the bracket nesting depth are bounded. It combines a Pentus-style tabularisation of proof nets with an automata-theoretic treatment of bracketing.Mobile graphics
http://hdl.handle.net/2117/113722
Mobile graphics
Agus, Marco; Gobbetti, Enrico; Marton, Fabio; Pintore, Giovanni; Vázquez Alcocer, Pere Pau
The increased availability and performance of mobile graphics terminals, including smartphones and tablets with high resolution screens and powerful GPUs, combined with the increased availability of high-speed mobile data connections, is opening the door to a variety of networked graphics applications. In this world, native apps or mobile sites coexist to reach the goal of providing us access to a wealth of multimedia information while we are on the move. This half-day tutorial provides a technical introduction to the mobile graphics world spanning the hardware-software spectrum, and explores the state of the art and key advances in specific application domains, including capture and acquisition, real-time high-quality 3D rendering and interactive exploration.
2018-02-05T10:47:37ZAgus, MarcoGobbetti, EnricoMarton, FabioPintore, GiovanniVázquez Alcocer, Pere PauThe increased availability and performance of mobile graphics terminals, including smartphones and tablets with high resolution screens and powerful GPUs, combined with the increased availability of high-speed mobile data connections, is opening the door to a variety of networked graphics applications. In this world, native apps or mobile sites coexist to reach the goal of providing us access to a wealth of multimedia information while we are on the move. This half-day tutorial provides a technical introduction to the mobile graphics world spanning the hardware-software spectrum, and explores the state of the art and key advances in specific application domains, including capture and acquisition, real-time high-quality 3D rendering and interactive exploration.Virtual reality to teach anatomy
http://hdl.handle.net/2117/113714
Virtual reality to teach anatomy
Fairén González, Marta; Farrés, Mariona; Moyes Ardiaca, Jordi; Insa, Esther
Virtual Reality (VR) and Augmented Reality (AR) have been gradually introduced in the curriculum of schools given the benefits they bring to classical education. We present an experiment designed to expose students to a VR session where they can directly inspect 3D models of several human organs by using Virtual Reality systems. Our systems allow the students to see the models directly visualized in 3D and to interact with them as if they were real. The experiment has involved 254 students of a Nursing Degree, enrolled in the Human anatomy and physiology course during 2 years (2 consecutive courses). It includes 10 3D models representing different anatomical structures which have been enhanced with meta-data to help the students understand the structure. In order to evaluate the students' satisfaction facing such a new teaching methodology, the students were asked to fill in a questionnaire with two categories. The first one measured whether or not, the teaching session using VR facilitates the understanding of the structures. The second one measured the student's satisfaction with this VR session. From the results we can see that the items most valuated are the use of the activity as a learning tool, and the satisfaction of the students' expectations. We can therefore conclude that VR session for teaching is a powerful learning tool that helps to understand the anatomical structures.
2018-02-05T10:35:39ZFairén González, MartaFarrés, MarionaMoyes Ardiaca, JordiInsa, EstherVirtual Reality (VR) and Augmented Reality (AR) have been gradually introduced in the curriculum of schools given the benefits they bring to classical education. We present an experiment designed to expose students to a VR session where they can directly inspect 3D models of several human organs by using Virtual Reality systems. Our systems allow the students to see the models directly visualized in 3D and to interact with them as if they were real. The experiment has involved 254 students of a Nursing Degree, enrolled in the Human anatomy and physiology course during 2 years (2 consecutive courses). It includes 10 3D models representing different anatomical structures which have been enhanced with meta-data to help the students understand the structure. In order to evaluate the students' satisfaction facing such a new teaching methodology, the students were asked to fill in a questionnaire with two categories. The first one measured whether or not, the teaching session using VR facilitates the understanding of the structures. The second one measured the student's satisfaction with this VR session. From the results we can see that the items most valuated are the use of the activity as a learning tool, and the satisfaction of the students' expectations. We can therefore conclude that VR session for teaching is a powerful learning tool that helps to understand the anatomical structures.Deep learning for detecting freezing of gait episodes in Parkinson’s disease based on accelerometers
http://hdl.handle.net/2117/113689
Deep learning for detecting freezing of gait episodes in Parkinson’s disease based on accelerometers
Camps, Julià; Samà Monsonís, Albert; Martín Muñoz, Mario; Rodríguez Martín, Daniel Manuel; Pérez López, Carlos; Alcaine, Sheila; Mestre, Berta; Prats, Anna; Crespo, M. Cruz; Cabestany Moncusí, Joan; Bayés, Àngels; Català Mallofré, Andreu
Freezing of gait (FOG) is one of the most incapacitating symptoms among the motor alterations of Parkinson’s disease (PD). Manifesting FOG episodes reduce patients’ quality of life and their autonomy to perform daily living activities, while it may provoke falls. Accurate ambulatory FOG assessment would enable non-pharmacologic support based on cues and would provide relevant information to neurologists on the disease evolution.
This paper presents a method for FOG detection based on deep learning and signal processing techniques. This is, to the best of our knowledge, the first time that FOG detection is addressed with deep learning. The evaluation of the model has been done based on the data from 15 PD patients who manifested FOG. An inertial measurement unit placed at the left side of the waist recorded tri-axial accelerometer, gyroscope and magnetometer signals. Our approach achieved comparable results to the state-of-the-art, reaching validation performances of 88.6% and 78% for sensitivity and specificity respectively.
The final publication is available at Springer via https://doi.org/10.1007/978-3-319-59147-6_30
2018-02-05T07:51:00ZCamps, JuliàSamà Monsonís, AlbertMartín Muñoz, MarioRodríguez Martín, Daniel ManuelPérez López, CarlosAlcaine, SheilaMestre, BertaPrats, AnnaCrespo, M. CruzCabestany Moncusí, JoanBayés, ÀngelsCatalà Mallofré, AndreuFreezing of gait (FOG) is one of the most incapacitating symptoms among the motor alterations of Parkinson’s disease (PD). Manifesting FOG episodes reduce patients’ quality of life and their autonomy to perform daily living activities, while it may provoke falls. Accurate ambulatory FOG assessment would enable non-pharmacologic support based on cues and would provide relevant information to neurologists on the disease evolution.
This paper presents a method for FOG detection based on deep learning and signal processing techniques. This is, to the best of our knowledge, the first time that FOG detection is addressed with deep learning. The evaluation of the model has been done based on the data from 15 PD patients who manifested FOG. An inertial measurement unit placed at the left side of the waist recorded tri-axial accelerometer, gyroscope and magnetometer signals. Our approach achieved comparable results to the state-of-the-art, reaching validation performances of 88.6% and 78% for sensitivity and specificity respectively.A datalog framework for modeling relationship-based access control policies
http://hdl.handle.net/2117/113608
A datalog framework for modeling relationship-based access control policies
Pasarella Sánchez, Ana Edelmira; Lobo, Jorge
Relationships like friendship to limit access to resources have been part of social network applications since their beginnings. Describing access control policies in terms of relationships is not particular to social networks and it arises naturally in many situations. Hence, we have recently seen several proposals formalizing different Relationship-based Access Control (ReBAC) models. In this paper, we introduce a class of Datalog programs suitable for modeling ReBAC and argue that this class of programs, that we called ReBAC Datalog policies, provides a very general framework to specify and implement ReBAC policies. To support our claim, we first formalize the merging of two recent proposals for modeling ReBAC, one based on hybrid logic and the other one based on path regular expressions. We present extensions to handle negative authorizations and temporal policies. We describe mechanism for policy analysis, and then discuss the feasibility of using Datalog-based systems as implementations.
SACMAT'17 Best paper
2018-02-02T10:13:31ZPasarella Sánchez, Ana EdelmiraLobo, JorgeRelationships like friendship to limit access to resources have been part of social network applications since their beginnings. Describing access control policies in terms of relationships is not particular to social networks and it arises naturally in many situations. Hence, we have recently seen several proposals formalizing different Relationship-based Access Control (ReBAC) models. In this paper, we introduce a class of Datalog programs suitable for modeling ReBAC and argue that this class of programs, that we called ReBAC Datalog policies, provides a very general framework to specify and implement ReBAC policies. To support our claim, we first formalize the merging of two recent proposals for modeling ReBAC, one based on hybrid logic and the other one based on path regular expressions. We present extensions to handle negative authorizations and temporal policies. We describe mechanism for policy analysis, and then discuss the feasibility of using Datalog-based systems as implementations.