LARCA - Laboratori d'Algorísmia Relacional, Complexitat i Aprenentatge
http://hdl.handle.net/2117/3486
Thu, 19 Sep 2019 21:07:33 GMT2019-09-19T21:07:33ZLARCA - Laboratori d'Algorísmia Relacional, Complexitat i Aprenentatgehttp://upcommons.upc.edu/bitstream/id/906643/
http://hdl.handle.net/2117/3486
Polysemy and brevity versus frequency in language
http://hdl.handle.net/2117/134935
Polysemy and brevity versus frequency in language
Casas Fernández, Bernardino; Hernández Fernández, Antonio; Catala Roig, Neus; Ferrer Cancho, Ramon; Baixeries i Juvillà, Jaume
The pioneering research of G. K. Zipf on the relationship between word frequency and other word features led to the formulation of various linguistic laws. The most popular is Zipf’s law for word frequencies. Here we focus on two laws that have been studied less intensively: the meaning-frequency law, i.e. the tendency of more frequent words to be more polysemous, and the law of abbreviation, i.e. the tendency of more frequent words to be shorter. In a previous work, we tested the robustness of these Zipfian laws for English, roughly measuring word length in number of characters and distinguishing adult from child speech. In the present article, we extend our study to other languages (Dutch and Spanish) and introduce two additional measures of length: syllabic length and phonemic length. Our correlation analysis indicates that both the meaning-frequency law and the law of abbreviation hold overall in all the analyzed languages.
Fri, 21 Jun 2019 11:41:55 GMThttp://hdl.handle.net/2117/1349352019-06-21T11:41:55ZCasas Fernández, BernardinoHernández Fernández, AntonioCatala Roig, NeusFerrer Cancho, RamonBaixeries i Juvillà, JaumeThe pioneering research of G. K. Zipf on the relationship between word frequency and other word features led to the formulation of various linguistic laws. The most popular is Zipf’s law for word frequencies. Here we focus on two laws that have been studied less intensively: the meaning-frequency law, i.e. the tendency of more frequent words to be more polysemous, and the law of abbreviation, i.e. the tendency of more frequent words to be shorter. In a previous work, we tested the robustness of these Zipfian laws for English, roughly measuring word length in number of characters and distinguishing adult from child speech. In the present article, we extend our study to other languages (Dutch and Spanish) and introduce two additional measures of length: syllabic length and phonemic length. Our correlation analysis indicates that both the meaning-frequency law and the law of abbreviation hold overall in all the analyzed languages.The sum of edge lengths in random linear arrangements
http://hdl.handle.net/2117/134020
The sum of edge lengths in random linear arrangements
Ferrer Cancho, Ramon
Spatial networks are networks where nodes are located in a space equipped with a metric. Typically, the space is two-dimensional and until recently and traditionally, the metric that was usually considered was the Euclidean distance. In spatial networks, the cost of a link depends on the edge length, i.e. the distance between the nodes that define the edge. Hypothesizing that there is pressure to reduce the length of the edges of a network requires a null model, e.g. a random layout of the vertices of the network. Here we investigate the properties of the distribution of the sum of edge lengths in random linear arrangement of vertices, that has many applications in different fields. A random linear arrangement consists of an ordering of the elements of the nodes of a network being all possible orderings equally likely. The distance between two vertices is one plus the number of intermediate vertices in the ordering. Compact formulae for the 1st and 2nd moments about zero as well as the variance of the sum of edge lengths are obtained for arbitrary graphs and trees. We also analyze the evolution of that variance in Erdos–Rényi graphs and its scaling in uniformly random trees. Various developments and applications for future research are suggested.
Thu, 06 Jun 2019 06:53:48 GMThttp://hdl.handle.net/2117/1340202019-06-06T06:53:48ZFerrer Cancho, RamonSpatial networks are networks where nodes are located in a space equipped with a metric. Typically, the space is two-dimensional and until recently and traditionally, the metric that was usually considered was the Euclidean distance. In spatial networks, the cost of a link depends on the edge length, i.e. the distance between the nodes that define the edge. Hypothesizing that there is pressure to reduce the length of the edges of a network requires a null model, e.g. a random layout of the vertices of the network. Here we investigate the properties of the distribution of the sum of edge lengths in random linear arrangement of vertices, that has many applications in different fields. A random linear arrangement consists of an ordering of the elements of the nodes of a network being all possible orderings equally likely. The distance between two vertices is one plus the number of intermediate vertices in the ordering. Compact formulae for the 1st and 2nd moments about zero as well as the variance of the sum of edge lengths are obtained for arbitrary graphs and trees. We also analyze the evolution of that variance in Erdos–Rényi graphs and its scaling in uniformly random trees. Various developments and applications for future research are suggested.Relative entailment among probabilistic implications
http://hdl.handle.net/2117/133669
Relative entailment among probabilistic implications
Atserias, Albert; Balcázar Navarro, José Luis; Piceno Cabrera, Marie Ely
We study a natural variant of the implicational fragment of propositional logic. Its formulas are pairs of conjunctions of positive literals, related together by an implicational-like connective; the semantics of this sort of implication is defined in terms of a threshold on a conditional probability of the consequent, given the antecedent: we are dealing with what the data analysis community calls confidence of partial implications or association rules. Existing studies of redundancy among these partial implications have characterized so far only entailment from one premise and entailment from two premises, both in the stand-alone case and in the case of presence of additional classical implications (this is what we call "relative entailment"). By exploiting a previously noted alternative view of the entailment in terms of linear programming duality, we characterize exactly the cases of entailment from arbitrary numbers of premises, again both in the stand-alone case and in the case of presence of additional classical implications. As a result, we obtain decision algorithms of better complexity; additionally, for each potential case of entailment, we identify a critical confidence threshold and show that it is, actually, intrinsic to each set of premises and antecedent of the conclusion.
Thu, 30 May 2019 07:11:14 GMThttp://hdl.handle.net/2117/1336692019-05-30T07:11:14ZAtserias, AlbertBalcázar Navarro, José LuisPiceno Cabrera, Marie ElyWe study a natural variant of the implicational fragment of propositional logic. Its formulas are pairs of conjunctions of positive literals, related together by an implicational-like connective; the semantics of this sort of implication is defined in terms of a threshold on a conditional probability of the consequent, given the antecedent: we are dealing with what the data analysis community calls confidence of partial implications or association rules. Existing studies of redundancy among these partial implications have characterized so far only entailment from one premise and entailment from two premises, both in the stand-alone case and in the case of presence of additional classical implications (this is what we call "relative entailment"). By exploiting a previously noted alternative view of the entailment in terms of linear programming duality, we characterize exactly the cases of entailment from arbitrary numbers of premises, again both in the stand-alone case and in the case of presence of additional classical implications. As a result, we obtain decision algorithms of better complexity; additionally, for each potential case of entailment, we identify a critical confidence threshold and show that it is, actually, intrinsic to each set of premises and antecedent of the conclusion.Weighted contrastive divergence
http://hdl.handle.net/2117/133368
Weighted contrastive divergence
Romero Merino, Enrique; Mazzanti Castrillejo, Fernando Pablo; Delgado Pin, Jordi; Buchaca Prats, David
Learning algorithms for energy based Boltzmann architectures that rely on gradient descent are in general computationally prohibitive, typically due to the exponential number of terms involved in computing the partition function. In this way one has to resort to approximation schemes for the evaluation of the gradient. This is the case of Restricted Boltzmann Machines (RBM) and its learning algorithm Contrastive Divergence (CD). It is well-known that CD has a number of shortcomings, and its approximation to the gradient has several drawbacks. Overcoming these defects has been the basis of much research and new algorithms have been devised, such as persistent CD. In this manuscript we propose a new algorithm that we call Weighted CD (WCD), built from small modifications of the negative phase in standard CD. However small these modifications may be, experimental work reported in this paper suggests that WCD provides a significant improvement over standard CD and persistent CD at a small additional computational cost.
Thu, 23 May 2019 06:51:27 GMThttp://hdl.handle.net/2117/1333682019-05-23T06:51:27ZRomero Merino, EnriqueMazzanti Castrillejo, Fernando PabloDelgado Pin, JordiBuchaca Prats, DavidLearning algorithms for energy based Boltzmann architectures that rely on gradient descent are in general computationally prohibitive, typically due to the exponential number of terms involved in computing the partition function. In this way one has to resort to approximation schemes for the evaluation of the gradient. This is the case of Restricted Boltzmann Machines (RBM) and its learning algorithm Contrastive Divergence (CD). It is well-known that CD has a number of shortcomings, and its approximation to the gradient has several drawbacks. Overcoming these defects has been the basis of much research and new algorithms have been devised, such as persistent CD. In this manuscript we propose a new algorithm that we call Weighted CD (WCD), built from small modifications of the negative phase in standard CD. However small these modifications may be, experimental work reported in this paper suggests that WCD provides a significant improvement over standard CD and persistent CD at a small additional computational cost.American and exotic options in a market with frictions
http://hdl.handle.net/2117/132516
American and exotic options in a market with frictions
Junike, Gero; Arratia Quesada, Argimiro Alejandro; Cabaña Nigro, Ana Alejandra; Schoutens, Wim
In a market with frictions, bid and ask prices are described by sublinear pricing functionals, which can be defined recursively using coherent risk measures. We prove the convergence of bid and ask prices for various European and American possible path-dependent options, in particular plain vanilla, Asian, lookback and barrier options in a binomial model with transaction costs. We perform several numerical experiments to confirm the theoretical findings. We apply the results to real market data of American options and compute an implied liquidity to describe the bidask
spread. This method describes liquidity over time very well, compared to the classical approach of describing bid and ask prices by quoting bid and ask implied volatilities.
Thu, 02 May 2019 11:34:04 GMThttp://hdl.handle.net/2117/1325162019-05-02T11:34:04ZJunike, GeroArratia Quesada, Argimiro AlejandroCabaña Nigro, Ana AlejandraSchoutens, WimIn a market with frictions, bid and ask prices are described by sublinear pricing functionals, which can be defined recursively using coherent risk measures. We prove the convergence of bid and ask prices for various European and American possible path-dependent options, in particular plain vanilla, Asian, lookback and barrier options in a binomial model with transaction costs. We perform several numerical experiments to confirm the theoretical findings. We apply the results to real market data of American options and compute an implied liquidity to describe the bidask
spread. This method describes liquidity over time very well, compared to the classical approach of describing bid and ask prices by quoting bid and ask implied volatilities.Averaging operators on decreasing or positive functions: equivalence and optimal bounds
http://hdl.handle.net/2117/131811
Averaging operators on decreasing or positive functions: equivalence and optimal bounds
Boza Rocho, Santiago; Soria de Diego, Javier
We study the optimal bounds for the Hardy operator S minus the identity, as well as S and its dualoperator S*, on the full range 1 = p = 8, for the cases of decreasing, positive or general functions (infact, these two kinds of inequalities are equivalent for the appropriate cone of functions). For 1< p = 2, we prove that all these estimates are the same, but for 2 < p <8, they exhibit a completely different behavior.
Tue, 23 Apr 2019 09:21:02 GMThttp://hdl.handle.net/2117/1318112019-04-23T09:21:02ZBoza Rocho, SantiagoSoria de Diego, JavierWe study the optimal bounds for the Hardy operator S minus the identity, as well as S and its dualoperator S*, on the full range 1 = p = 8, for the cases of decreasing, positive or general functions (infact, these two kinds of inequalities are equivalent for the appropriate cone of functions). For 1< p = 2, we prove that all these estimates are the same, but for 2 < p <8, they exhibit a completely different behavior.Linguistic laws in chimpanzee gestural communication
http://hdl.handle.net/2117/131628
Linguistic laws in chimpanzee gestural communication
Heesen, Raphaela; Hobaiter, Catherine; Ferrer Cancho, Ramon; Semple, Stuart
Studies testing linguistic laws outside language have provided important insights into the organization of biological systems. For example, patterns consistent with Zipf's law of abbreviation (which predicts a negative relationship between word length and frequency of use) have been found in the vocal and non-vocal behaviour of a range of animals, and patterns consistent with Menzerath's law (according to which longer sequences are made up of shorter constituents) have been found in primate vocal sequences, and in genes, proteins and genomes. Both laws have been linked to compression—the information theoretic principle of minimizing code length. Here, we present the first test of these laws in animal gestural communication. We initially did not find the negative relationship between gesture duration and frequency of use predicted by Zipf's law of abbreviation, but this relationship was seen in specific subsets of the repertoire. Furthermore, a pattern opposite to that predicted was seen in one subset of gestures—whole body signals. We found a negative correlation between number and mean duration of gestures in sequences, in line with Menzerath's law. These results provide the first evidence that compression underpins animal gestural communication, and highlight an important commonality between primate gesturing and language.
Thu, 11 Apr 2019 09:26:05 GMThttp://hdl.handle.net/2117/1316282019-04-11T09:26:05ZHeesen, RaphaelaHobaiter, CatherineFerrer Cancho, RamonSemple, StuartStudies testing linguistic laws outside language have provided important insights into the organization of biological systems. For example, patterns consistent with Zipf's law of abbreviation (which predicts a negative relationship between word length and frequency of use) have been found in the vocal and non-vocal behaviour of a range of animals, and patterns consistent with Menzerath's law (according to which longer sequences are made up of shorter constituents) have been found in primate vocal sequences, and in genes, proteins and genomes. Both laws have been linked to compression—the information theoretic principle of minimizing code length. Here, we present the first test of these laws in animal gestural communication. We initially did not find the negative relationship between gesture duration and frequency of use predicted by Zipf's law of abbreviation, but this relationship was seen in specific subsets of the repertoire. Furthermore, a pattern opposite to that predicted was seen in one subset of gestures—whole body signals. We found a negative correlation between number and mean duration of gestures in sequences, in line with Menzerath's law. These results provide the first evidence that compression underpins animal gestural communication, and highlight an important commonality between primate gesturing and language.The polysemy of the words that children learn over time
http://hdl.handle.net/2117/130754
The polysemy of the words that children learn over time
Casas Fernández, Bernardino; Catala Roig, Neus; Ferrer Cancho, Ramon; Hernández Fernández, Antonio; Baixeries i Juvillà, Jaume
Here we study polysemy as a potential learning bias in vocabulary learning in children. We employ a massive set of transcriptions of conversations between children and adults in English, to analyze the evolution of mean polysemy in the words produced by children whose ages range between 10 and 60 months.
Our results show that mean polysemy in children increases over time in two phases, i.e. a fast growth till the 31st month followed by a slower tendency towards adult speech. In contrast, no dependency with time is found in adults. This may suggest that children have a preference for non-polysemous words in their early stages of vocabulary acquisition. Our hypothesis is twofold: (a) polysemy is a standalone bias or (b) polysemy is a side-effect of other biases. Interestingly, the bias for low polysemy above weakens when controlling by syntactic category (noun, verb, adjective or adverb). The pattern of the evolution of polysemy suggests that both hypotheses may apply to some extent, and that (b) would originate from a combination of the well-known preference for nouns and the lower polysemy of nouns with respect to other syntactic categories.
Fri, 22 Mar 2019 09:29:47 GMThttp://hdl.handle.net/2117/1307542019-03-22T09:29:47ZCasas Fernández, BernardinoCatala Roig, NeusFerrer Cancho, RamonHernández Fernández, AntonioBaixeries i Juvillà, JaumeHere we study polysemy as a potential learning bias in vocabulary learning in children. We employ a massive set of transcriptions of conversations between children and adults in English, to analyze the evolution of mean polysemy in the words produced by children whose ages range between 10 and 60 months.
Our results show that mean polysemy in children increases over time in two phases, i.e. a fast growth till the 31st month followed by a slower tendency towards adult speech. In contrast, no dependency with time is found in adults. This may suggest that children have a preference for non-polysemous words in their early stages of vocabulary acquisition. Our hypothesis is twofold: (a) polysemy is a standalone bias or (b) polysemy is a side-effect of other biases. Interestingly, the bias for low polysemy above weakens when controlling by syntactic category (noun, verb, adjective or adverb). The pattern of the evolution of polysemy suggests that both hypotheses may apply to some extent, and that (b) would originate from a combination of the well-known preference for nouns and the lower polysemy of nouns with respect to other syntactic categories.Fermi : la energía nuclear : la fisión hace la fuerza
http://hdl.handle.net/2117/130640
Fermi : la energía nuclear : la fisión hace la fuerza
Hernández Fernández, Antonio
Enrico Fermi participó en la revolución de la física de la primera mitad del siglo xx. Su ciclópea labor propició un conocimiento más profundo de las partículas del universo cuántico, y de su capacidad de escudriñar la materia surgió buena parte de la tecnología nuclear que conocemos. La increíble era atómica, con su poder extremo, pero también con sus fantasmas, desastres y dilemas éticos, llegó de su mano para convivir con la humanidad hasta la actualidad.
Wed, 20 Mar 2019 08:32:21 GMThttp://hdl.handle.net/2117/1306402019-03-20T08:32:21ZHernández Fernández, AntonioEnrico Fermi participó en la revolución de la física de la primera mitad del siglo xx. Su ciclópea labor propició un conocimiento más profundo de las partículas del universo cuántico, y de su capacidad de escudriñar la materia surgió buena parte de la tecnología nuclear que conocemos. La increíble era atómica, con su poder extremo, pero también con sus fantasmas, desastres y dilemas éticos, llegó de su mano para convivir con la humanidad hasta la actualidad.Ús de Kahoot! com a eina de ludificació per a la retroalimentació a temps
http://hdl.handle.net/2117/130574
Ús de Kahoot! com a eina de ludificació per a la retroalimentació a temps
Pàmies Vilà, Rosa; Fabregat Sanjuan, Albert; Puig Ortiz, Joan; Jordi Nebot, Lluïsa; Hernández Fernández, Antonio
Es presenta l’actuació duta a terme en les pràctiques de Teoria de Màquines i Mecanismes de l’ETSEIB. S’introdueix una retroalimentació a temps mitjançant l’aplicació Kahoot! la qual cosa permet estimular l’interès de l’alumnat i ajudar a adquirir els coneixements de l’assignatura amb les metodologies típiques de l’aprenentatge basat en jocs. Els resultats mostren millores significatives en els grups on s’ha dut a terme l’actuació i aporten evidències en favor de la ludificació.
Tue, 19 Mar 2019 10:19:31 GMThttp://hdl.handle.net/2117/1305742019-03-19T10:19:31ZPàmies Vilà, RosaFabregat Sanjuan, AlbertPuig Ortiz, JoanJordi Nebot, LluïsaHernández Fernández, AntonioEs presenta l’actuació duta a terme en les pràctiques de Teoria de Màquines i Mecanismes de l’ETSEIB. S’introdueix una retroalimentació a temps mitjançant l’aplicació Kahoot! la qual cosa permet estimular l’interès de l’alumnat i ajudar a adquirir els coneixements de l’assignatura amb les metodologies típiques de l’aprenentatge basat en jocs. Els resultats mostren millores significatives en els grups on s’ha dut a terme l’actuació i aporten evidències en favor de la ludificació.