518 research outputs found
Algebraic Solutions of the Lam\'e Equation, Revisited
A minor error in the necessary conditions for the algebraic form of the
Lam\'e equation to have a finite projective monodromy group, and hence for it
to have only algebraic solutions, is pointed out. [See F. Baldassarri, "On
algebraic solutions of Lam\'e's differential equation", J. Differential
Equations 41 (1981), 44-58.] It is shown that if the group is the octahedral
group S_4, then the degree parameter of the equation may differ by +1/6 or -1/6
from an integer; this possibility was missed. The omission affects a recent
result on the monodromy of the Weierstrass form of the Lam\'e equation. [See R.
C. Churchill, "Two-generator subgroups of SL(2,C) and the hypergeometric,
Riemann, and Lam\'e equations", J. Symbolic Computation 28 (1999), 521-545.]
The Weierstrass form, which is a differential equation on an elliptic curve,
may have, after all, an octahedral projective monodromy group.Comment: 20 pages, elsart document class, no figure
Chemical fracture and distribution of extreme values
When a corrosive solution reaches the limits of a solid sample, a chemical
fracture occurs. An analytical theory for the probability of this chemical
fracture is proposed and confirmed by extensive numerical experiments on a two
dimensional model. This theory follows from the general probability theory of
extreme events given by Gumbel. The analytic law differs from the Weibull law
commonly used to describe mechanical failures for brittle materials. However a
three parameters fit with the Weibull law gives good results, confirming the
empirical value of this kind of analysis.Comment: 7 pages, 5 figures, to appear in Europhysics Letter
Interactive Embodied Agents for Cultural Heritage and Archaeological presentations
[EN] In this paper, Maxine, a powerful engine to develop applications with embodied animated agents is presented. The engine, based on the use of open source libraries, enables multimodal real-time interaction with the user: via text, voice, images and gestures. Maxine virtual agents can establish emotional communication with the user through their facial expressions, the modulation of the voice and expressing the answers of the agents according to the information gathered by the system: noise level in the room, observer’s position, emotional state of the observer, etc. Moreover, the user’s emotions are considered and captured through images. For the moment, Maxine virtual agents have been used as virtual presenters for Cultural Heritage and Archaeological shows.This work has been partially financed by the Spanish “Dirección General de Investigación'' (General Directorate of Research), contract
number Nº TIN2007-63025, and by the Regional Government of Aragon through the WALQA agreement.Seron, F.; Baldassarri, S.; Cerezo, E. (2010). Interactive Embodied Agents for Cultural Heritage and Archaeological presentations. Virtual Archaeology Review. 1(1):181-184. https://doi.org/10.4995/var.2010.5143OJS18118411BALDASSARRI, S., CEREZO, E., SERON, F. (2007): An open source engine for embodied animated agents.In Proc. Congreso Español de Informática Gráfica: CEIG'07, pp. 89-98.BERRY, D.et al, (2005). Evaluating a realistic agent in an advice-giving task. In International Journal in Human-Computer Studies, Nº 63, pp. 304-327. http://dx.doi.org/10.1016/j.ijhcs.2005.03.006BOFF, E. et al, (2005). An affective agent-based virtual character for learning environments. Proceedings of the Wokshop on Motivation and Affect in Educational Software, 12th International Conference on Artificial Intelligence in Education. Amsterdam, Holland, pp 1-8.BURLESON, W. et al, (2004). A Platform for Affective Agent Research. Proceedings of the Workshop on Empathetic Agents, International Conference on Autonomous Agents and Multiagent Systems, New York, USA.CEREZO, E., BALDASSARRI, S., SERON, F. (2007): Interactive agents for multimodal emotional user interaction. In Proc. of IADIS International Conference Interfaces and Human Computer Interaction, pp. 35-42.CASELL, J. et al (eds), (2000), in Embodied Conversational Agents. MIT Press, Cambridge, USA.El-NASR, M. S. et al, (1999). A PET with Evolving Emotional Intelligence. Proceedings of the 3rd Annual Conference on Autonomous Agents. Seattle, USA, pp. 9 - 15. http://dx.doi.org/10.1145/301136.301150GRAESSER, A. et al, (2005). AutoTutor: An Intelligent tutoring system with mixed-initiative dialogue. In IEEE Transactions on Education, Vol. 48, Nº 4, pp. 612-618. http://dx.doi.org/10.1109/TE.2005.856149KASAP, Z. and N. MAGNENAT-THALMANN (2007): "Intelligent virtual humans with autonomy and personality: State-of-the-art", in IntelligentDecision Technologies. IOS PressMARSELLA S. C et al, (2000). Interactive Pedagogical Drama. Proceedings of the 4th International Conference on Autonomous Agents. Barcelona, Spain, pp. 301-308. http://dx.doi.org/10.1145/336595.337507MIGNONNEAU, L. and SOMMERER, C. (2005). Designing emotional, methaforic, natural and intuitive interfaces for interactive art, edutainment and mobile communications, in Computer & Graphics, Vol. 29, pp. 837-851.PRENDINGER, H. and ISHIZUKA, M., (2005). The Empathic Companion: A Character-Based Interface that Addresses Users' Affective States. In Applied Artificial Intelligence, Vol.19, pp.267-285. http://dx.doi.org/10.1080/08839510590910174ROSIS, F. et al, (2003). From Greta's mind to her face: modelling the dynamics of affective status in a conversational embodied agent. In International Journal of Human-computer Studies. Special Issue on Applications of Affective Computing in HCI, Vol 59, pp 81-118. http://dx.doi.org/10.1016/s1071-5819(03)00020-xYUAN, X. and CHEE, S. (2005). Design and evaluation of Elva: an embodied tour guide in an interactive virtual art gallery. In Computer Animation and Virtual Worlds, Vol. 16, pp.109-119. http://dx.doi.org/10.1002/cav.6
High-level libraries for emotion recognition in music: A review
This article presents a review of high-level libraries that enable to recognize emotions in digital files of music. The main objective of the work is to study and compare different high-level content-analyzer libraries, showing their main functionalities, focused on the extraction of low and high level relevant features to classify musical pieces through an affective classification model. In addition, there has been a review of different works in which those libraries have been used to emotionally classify the musical pieces, through rhythmic and tonal features reconstruction, and the automatic annotation strategies applied, which generally incorporate machine learning techniques. For the comparative evaluation of the different high-level libraries, in addition to the common attributes in the chosen libraries, the most representative attributes in music emotion recognition field (MER) were selected. The comparative evaluation enables to identify the current development in MER regarding high-level libraries and to analyze the musical parameters that are related with emotions
Distant Supervised Construction and Evaluation of a Novel Dataset of Emotion-Tagged Social Media Comments in Spanish
Tagged language resources are an essential requirement for developing machine-learning text-based classifiers. However, manual tagging is extremely time consuming and the resulting datasets are rather small, containing only a few thousand samples. Basic emotion datasets are particularly difficult to classify manually because categorization is prone to subjectivity, and thus, redundant classification is required to validate the assigned tag. Even though, in recent years, the amount of emotion-tagged text datasets in Spanish has been growing, it cannot be compared with the number, size, and quality of the datasets in English. Quality is a particularly concerning issue, as not many datasets in Spanish included a validation step in the construction process. In this article, a dataset of social media comments in Spanish is compiled, selected, filtered, and presented. A sample of the dataset is reclassified by a group of psychologists and validated using the Fleiss Kappa interrater agreement measure. Error analysis is performed by using the Sentic Computing tool BabelSenticNet. Results indicate that the agreement between the human raters and the automatically acquired tag is moderate, similar to other manually tagged datasets, with the advantages that the presented dataset contains several hundreds of thousands of tagged comments and it does not require extensive manual tagging. The agreement measured between human raters is very similar to the one between human raters and the original tag. Every measure presented is in the moderate agreement zone and, as such, suitable for training classification algorithms in sentiment analysis field
Analytical results for generalized persistence properties of smooth processes
We present a general scheme to calculate within the independent interval
approximation generalized (level-dependent) persistence properties for
processes having a finite density of zero-crossings. Our results are especially
relevant for the diffusion equation evolving from random initial conditions,
one of the simplest coarsening systems. Exact results are obtained in certain
limits, and rely on a new method to deal with constrained multiplicative
processes. An excellent agreement of our analytical predictions with direct
numerical simulations of the diffusion equation is found.Comment: 21 pages, 4 figures, to appear in Journal of Physics
Toward emotional interactive videogames for children with autism spectrum disorder
Technology and videogames have been proven as motivating tools for working attention and complex communication skills, especially in children with autism spectrum disorder (ASD). In this work, we present two experiences that used interactive games for promoting communication and attention. The first game considers emotions in order to measure children’s attention, concentration and satisfaction, while the second uses tangible tabletops for fostering cognitive planning. The analysis of the results obtained allows to propose a new study integrating both, in which the tangible interactive game is complemented with the emotional trainer in a way that allows identifying and classifying children’s emotion with ASD when they collaborate to solve cognitively significant and contextualized challenges. The first application proposed is an emotional trainer application in which the child can work out the seven basic emotions (happiness, sadness, fear, disgust, anger, surprise and neutral). Further, a serious videogame is proposed: a 3D maze where the emotions can be captured. The second case study was carried out in a Special Education Center, where a set of activities for working cognitive planning was proposed. In this case, a tangible interactive tabletop was used to analyze, in students with ASD, how the communication processes with these interfaces affect to the attention, memory, successive and simultaneous processing that compose cognitive planning from the PASS model. The results of the first study, suggest that the autistic children did not act with previous planning, but they used their perception to adjust their actions a posteriori (that explains the higher number of collisions). On the second case study, the successive processing was not explored. The inclusion of the mazes of case study 1 to a semantic rich scenario could allow us to measure the prior planning and the emotions involved in the maze game. The new physiological sensors will also help to validate the emotions felt by the children. The first study has as objective the capability to imitate emotions and resolve a maze without semantic context. The second study organized all the actions from a semantic context close to users. The attention results presented by the second study are coherent with the first study and complement it showing that attention can be receptive or selective. In the first study case, the receptive attention was the focus of analysis. In the second case, both contributed to explain and understand how it can be developed from a videogame
SUSApp: a mobile app for measuring and comparing questionnaire-based usability assessments
Usability questionnaires are one of the most used methods to
measure usability in terms of the user’s subjective satisfaction.
However, most of the usability questionnaires do not provide a
complete environment to store measurements and compare
different usability values of application categories and versions
over the long term, which makes it difficult to study the usability
of a software product or even the usability of different versions of
such products over time, hindering the facility to obtain
comparisons and thresholds in usability measurements for
different product lines. In this paper we present SUSApp, a tool
conceived for the analysis of usability through the SUS (System
Usability Scale) questionnaire, which is one of the most popular
ones. This tool was conceived for mobile platforms, and it is
intended to easily analyze usability by storing and recovering past
evaluations, and allowing to statistically compare usability
measurements among different software products and applications
categories. In addition, a user testing is presented. This has
provided acceptable usability results concerning SUSApp in an
experiment with real usersThis work has been partially supported by the funding projects
«eMadrid-CM», granted by the Madrid Research Council (project
code S2013/ICE-2715), and «Flexor» granted by the Spanish
Government (project code TIN2014-52129-R
The Role of Trauma in Early Onset Borderline Personality Disorder: A Biopsychosocial Perspective
The role of childhood trauma in the development of borderline personality disorder (BPD) in young age has long been studied. The most accurate theoretical models are multifactorial, taking into account a range of factors, including early trauma, to explain evolutionary pathways of BPD. We reviewed studies published on PubMed in the last 20 years to evaluate whether different types of childhood trauma, like sexual and physical abuse and neglect, increase the risk and shape the clinical picture of BPD. BPD as a sequela of childhood traumas often occurs with multiple comorbidities (e.g. mood, anxiety, obsessive-compulsive, eating, dissociative, addictive, psychotic, and somatoform disorders). In such cases it tends to have a prolonged course, to be severe, and treatment-refractory. In comparison with subjects who suffer from other personality disorders, patients with BPD experience childhood abuse more frequently. Adverse childhood experiences affect different biological systems (HPA axis, neurotransmission mechanisms, endogenous opioid systems, gray matter volume, white matter connectivity), with changes persisting into adulthood. A growing body of evidence is emerging about interaction between genes (e.g. FKBP5 polymorphisms and CRHR2 variants) and environment (physical and sexual abuse, emotional neglect)
The average shape of a fluctuation: universality in excursions of stochastic processes
We study the average shape of a fluctuation of a time series x(t), that is
the average value _T before x(t) first returns, at time T, to its
initial value x(0). For large classes of stochastic processes we find that a
scaling law of the form _T = T^\alpha f(t/T) is obeyed. The
scaling function f(s) is to a large extent independent of the details of the
single increment distribution, while it encodes relevant statistical
information on the presence and nature of temporal correlations in the process.
We discuss the relevance of these results for Barkhausen noise in magnetic
systems.Comment: 5 pages, 5 figures, accepted for publication in Phys. Rev. Let
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