A Production System Model of Capturing Reactive Moving Targets

Subjects manipulated a control stick to position a cursor over a moving target that reacted with a computer-generated escape strategy. The cursor movements were described at two levels of abstraction. At the upper level, a production system described transitions among four modes of activity; rapid acquisition, close following, a predictive mode, and herding. Within each mode, differential equations described trajectory-generating mechanisms. A simulation of this two-level model captures the targets in a manner resembling the episodic time histories of human subjects

Spontaneous self-ordered states of vortex-antivortex pairs in a Polariton Condensate

Polariton condensates have proved to be model systems to investigate topological defects, as they allow for direct and non-destructive imaging of the condensate complex order parameter. The fundamental topological excitations of such systems are quantized vortices. In specific configurations, further ordering can bring the formation of vortex lattices. In this work we demonstrate the spontaneous formation of ordered vortical states, consisting in geometrically self-arranged vortex-antivortex pairs. A mean-field generalized Gross-Pitaevskii model reproduces and supports the physics of the observed phenomenology

Biografo: An integrated tool for forensic writer identification

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-20125-2_17The design and performance of a practical integrated tool for writer identification in forensic scenarios is presented. The tool has been designed to help forensic examiners along the complete identification process: from the data acquisition to the recognition itself, as well as with the management of large writer-related databases. The application has been implemented using JavaScript running over a relational database which provides the whole system with some very desirable and unique characteristics such as the possibility to perform all type of queries (e.g., find individuals with some very discriminative character, find a specific document, display all the samples corresponding to one writer, etc.), or a complete control over the set of parameters we want to use in a specific recognition task (e.g., users in the database to be used as control set, set of characters to be used in the identification, size of the ranked list we want as final result, etc.). The identification performance of the tool is evaluated on a real-case forensic database showing some very promising results.This work has been partially supported by the Spanish Dirección General de la Guardia Civil, and projects Contexts (S2009/TIC-1485) from CAM, Bio-Challenge (TEC2009-11186) from Spanish MICINN, BBfor2 (ITN-2008-238803) from the European Commision, and Cátedra UAM-Telefónica

Offline Signature Verification by Combining Graph Edit Distance and Triplet Networks

Biometric authentication by means of handwritten signatures is a challenging pattern recognition task, which aims to infer a writer model from only a handful of genuine signatures. In order to make it more difficult for a forger to attack the verification system, a promising strategy is to combine different writer models. In this work, we propose to complement a recent structural approach to offline signature verification based on graph edit distance with a statistical approach based on metric learning with deep neural networks. On the MCYT and GPDS benchmark datasets, we demonstrate that combining the structural and statistical models leads to significant improvements in performance, profiting from their complementary properties

The Dipole Moment of Styrene

The dipole moment of styrene, calculated from eighteen solutions ranging in weight fraction from 0 - 100%, was found to be 0.181 D. The method and results of the measurement were compared to the method and results of Petro and Smyth for the same compound. It was concluded that the atomic polarization in styrene in small, and thus is taken into account by the measurement of the molar refraction at the sodium D line. It was further proposed that the relatively large dipole moments of trans-p, βdinitrostyrene and trans-p, βdicyano-styrene may be due, at least in part, to abnormally large atomic polarizations

Neuronal Variability during Handwriting: Lognormal Distribution

We examined time-dependent statistical properties of electromyographic (EMG) signals recorded from intrinsic hand muscles during handwriting. Our analysis showed that trial-to-trial neuronal variability of EMG signals is well described by the lognormal distribution clearly distinguished from the Gaussian (normal) distribution. This finding indicates that EMG formation cannot be described by a conventional model where the signal is normally distributed because it is composed by summation of many random sources. We found that the variability of temporal parameters of handwriting - handwriting duration and response time - is also well described by a lognormal distribution. Although, the exact mechanism of lognormal statistics remains an open question, the results obtained should significantly impact experimental research, theoretical modeling and bioengineering applications of motor networks. In particular, our results suggest that accounting for lognormal distribution of EMGs can improve biomimetic systems that strive to reproduce EMG signals in artificial actuators

Gaussian curves for signature modelization and word segmentation

This paper presents the use of a handwriting generation mode! for signature reconstruction and word segmentation . This mode! is based on two velocity generators : a curvilinear velocity generator and an angular velocity generator . In the curvilinear and the angular domains, the mode! estimates velocity profiles with a series of gaussian curves . In the first part of this paper, the theoretic mode! and the underlying concepts are described. Then the validity of the mode! is tested on various kind of signatures (european, chinese, north-american) . At the end of this paper the mode! is used for cursive word segmentation and the results are discussed.Cet article traite de l'utilisation d'un modèle de génération de traces manuscrits pour la synthèse de signatures et la segmentation de mots manuscrits. Ce modèle est basé sur l'intégration de vitesse provenant de deux générateurs: un générateur de vitesse curviligne et un générateur de vitesse angulaire. Dans les domaines curviligne et angulaire, le modèle approxime les profils de vitesse par une succession de fonctions gaussiennes. Le début de cet article comporte une description du modèle théorique et des concepts sous-jacents qui ont permis d'établir ses base

Online Signature Verification: Improving Performance through Pre-classification Based on Global Features

In this paper, a pre-classification stage based on global features is incorporated to an online signature verification system for the purposes of improving its performance. The pre-classifier makes use of the discriminative power of some global features to discard (by declaring them as forgeries) those signatures for which the associated global feature is far away from its respective mean. For the remaining signatures, features based on a wavelet approximation of the time functions associated with the signing process, are extracted, and a Random Forest based classification is performed. The experimental results show that the proposed pre-classification approach, when based on the apppropriate global feature, is capable of getting error rate improvements with respect to the case where no pre-classification is performed. The approach also has the advantages of simplifying and speeding up the verification process.Fil: Parodi, Marianela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y Sistemas; ArgentinaFil: Gómez, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Rosario. Centro Internacional Franco Argentino de Ciencias de la Información y Sistemas; Argentin

Multimodal output combination for transcribing historical handwritten documents

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-23192-1_21Transcription of digitalised historical documents is an interesting task in the document analysis area. This transcription can be achieved by using Handwritten Text Recognition (HTR) on digitalised pages or by using Automatic Speech Recognition (ASR) on the dictation of contents. Moreover, another option is using both systems in a multimodal combination to obtain a draft transcription, given that combining the outputs of different recognition systems will generally improve the recognition accuracy. In this work, we present a new combination method based on Confusion Network. We check its effectiveness for transcribing a Spanish historical book. Results on both unimodal combination with different optical (for HTR) and acoustic (for ASR) models, and multimodal combination, show a relative reduction of Word and Character Error Rate of 14.3% and 16.6%, respectively, over the HTR baseline.Work partially supported by European Union -7th FP, under grant 600707 (tranScriptorium), and by the Spanish MEC under projects STraDA (TIN2012-37475-C02-01), Active2Trans (TIN2012-31723), and SmartWays (RTC-2014-1466-4).Granell Romero, E.; Martínez-Hinarejos, C. (2015). Multimodal output combination for transcribing historical handwritten documents. En Computer Analysis of Images and Patterns. Springer. 246-260. https://doi.org/10.1007/978-3-319-23192-1_21S246260Alabau, V., Martínez-Hinarejos, C.D., Romero, V., Lagarda, A.L.: An iterative multimodal framework for the transcription of handwritten historical documents. 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Acoustics, Speech and Signal Processing, vol. 3, pp. 1635–1638 (2000)Ishimaru, S., Nishizaki, H., Sekiguchi, Y.: Effect of confusion network combination on speech recognition system for editing. In: Proc. of APSIPA Annual Summit and Conf., vol. 4, pp. 1–4 (2011)Johnson, D.: ICSI Quicknet soft package (2004). http://www1.icsi.berkeley.edu/Speech/qn.htmlKneser, R., Ney, H.: Improved backing-off for m-gram language modeling. In: Proc. of Int. Conf. Acoustics, Speech and Signal Processing, vol. 1, pp. 181–184 (1995)Krishnamurthy, H.K.: Study of algorithms to combine multiple automatic speech recognition (ASR) system outputs. Master’s thesis, Department of Electrical and Computer Engineering (2009). http://hdl.handle.net/2047/d10019273Luján-Mares, M., Tamarit, V., Alabau, V., Martínez-Hinarejos, C.D., Pastor i Gadea, M., Sanchis, A., Toselli, A.H.: iATROS: a speech and handwritting recognition system. In: V Jornadas en Tecnologías del Habla (VJTH2008), pp. 75–78 (2008)Moreno, A., Poch, D., Bonafonte, A., Lleida, E., Llisterri, J., Mariño, J.B., Nadeu, C.: Albayzin speech database: design of the phonetic corpus. In: Proc. of EuroSpeech 1993, pp. 175–178 (1993)Netpbm home page. http://netpbm.sourceforge.net/Plamondon, R., Srihari, S.N.: On-Line and Off-Line Handwriting Recognition: A Comprehensive Survey. IEEE Transactions on Pattern Analysis and Machine Intelligence 22(1), 63–84 (2000)Romero, V., Leiva, L.A., Toselli, A.H., Vidal, E.: Interactive multimodal transcription of text images using a web-based demo system. In: Proc. of Conf. on Intelligent User Interfaces, pp. 477–478 (2009)Serrano, N., Castro, F., Juan, A.: The RODRIGO Database. In: Proc. of Language Resources and Evaluation Conference, pp. 2709–2712 (2010)Stolcke, A.: SRILM - an extensible language modeling toolkit. In: Proc. Interspeech, pp. 901–904 (2002)Woodruff, P., Dupont, S.: Bimodal combination of speech and handwriting for improved word recognition. In: Proc. of EUSIPCO 2005, pp. 1918–1921 (2005)Xue, J., Zhao, Y.: Improved confusion network algorithm and shortest path search from word lattice. In: Proc. of Int. Conf. in Acoustics, Speech and Signal Processing, vol. 1, pp. 853–856 (2005)Young, S., Evermann, G., Gales, M., Hain, T., Kershaw, D., Liu, X., Moore, G., Odell, J., Ollason, D., Povey, D., et al.: The HTK book (for HTK version 3.4). Cambridge university Eng. Dept. (2006)Zhai, C., Lafferty, J.: A study of smoothing methods for language models applied to information retrieval. Transactions on Information Systems 22(2), 179–214 (2004

The effect of distance on reaction time in aiming movements

Target distance affects movement duration in aiming tasks but its effect on reaction time (RT) is poorly documented. RT is a function of both preparation and initiation. Experiment 1 pre-cued movement (allowing advanced preparation) and found no influence of distance on RT. Thus, target distance does not affect initiation time. Experiment 2 removed pre-cue information and found that preparing a movement of increased distance lengthens RT. Experiment 3 explored movements to targets of cued size at non-cued distances and found size altered peak speed and movement duration but RT was influenced by distance alone. Thus, amplitude influences preparation time (for reasons other than altered duration) but not initiation time. We hypothesise that the RT distance effect might be due to the increased number of possible trajectories associated with further targets: a hypothesis that can be tested in future experiments