A Unified Multilingual Handwriting Recognition System using multigrams sub-lexical units

We address the design of a unified multilingual system for handwriting recognition. Most of multi- lingual systems rests on specialized models that are trained on a single language and one of them is selected at test time. While some recognition systems are based on a unified optical model, dealing with a unified language model remains a major issue, as traditional language models are generally trained on corpora composed of large word lexicons per language. Here, we bring a solution by con- sidering language models based on sub-lexical units, called multigrams. Dealing with multigrams strongly reduces the lexicon size and thus decreases the language model complexity. This makes pos- sible the design of an end-to-end unified multilingual recognition system where both a single optical model and a single language model are trained on all the languages. We discuss the impact of the language unification on each model and show that our system reaches state-of-the-art methods perfor- mance with a strong reduction of the complexity.Comment: preprin

Efficient hardware implementations of bio-inspired networks

The human brain, with its massive computational capability and power efficiency in small form factor, continues to inspire the ultimate goal of building machines that can perform tasks without being explicitly programmed. In an effort to mimic the natural information processing paradigms observed in the brain, several neural network generations have been proposed over the years. Among the neural networks inspired by biology, second-generation Artificial or Deep Neural Networks (ANNs/DNNs) use memoryless neuron models and have shown unprecedented success surpassing humans in a wide variety of tasks. Unlike ANNs, third-generation Spiking Neural Networks (SNNs) closely mimic biological neurons by operating on discrete and sparse events in time called spikes, which are obtained by the time integration of previous inputs. Implementation of data-intensive neural network models on computers based on the von Neumann architecture is mainly limited by the continuous data transfer between the physically separated memory and processing units. Hence, non-von Neumann architectural solutions are essential for processing these memory-intensive bio-inspired neural networks in an energy-efficient manner. Among the non-von Neumann architectures, implementations employing non-volatile memory (NVM) devices are most promising due to their compact size and low operating power. However, it is non-trivial to integrate these nanoscale devices on conventional computational substrates due to their non-idealities, such as limited dynamic range, finite bit resolution, programming variability, etc. This dissertation demonstrates the architectural and algorithmic optimizations of implementing bio-inspired neural networks using emerging nanoscale devices. The first half of the dissertation focuses on the hardware acceleration of DNN implementations. A 4-layer stochastic DNN in a crossbar architecture with memristive devices at the cross point is analyzed for accelerating DNN training. This network is then used as a baseline to explore the impact of experimental memristive device behavior on network performance. Programming variability is found to have a critical role in determining network performance compared to other non-ideal characteristics of the devices. In addition, noise-resilient inference engines are demonstrated using stochastic memristive DNNs with 100 bits for stochastic encoding during inference and 10 bits for the expensive training. The second half of the dissertation focuses on a novel probabilistic framework for SNNs using the Generalized Linear Model (GLM) neurons for capturing neuronal behavior. This work demonstrates that probabilistic SNNs have comparable perform-ance against equivalent ANNs on two popular benchmarks - handwritten-digit classification and human activity recognition. Considering the potential of SNNs in energy-efficient implementations, a hardware accelerator for inference is proposed, termed as Spintronic Accelerator for Probabilistic SNNs (SpinAPS). The learning algorithm is optimized for a hardware friendly implementation and uses first-to-spike decoding scheme for low latency inference. With binary spintronic synapses and digital CMOS logic neurons for computations, SpinAPS achieves a performance improvement of 4x in terms of GSOPS/W/mm$^2$ when compared to a conventional SRAM-based design. Collectively, this work demonstrates the potential of emerging memory technologies in building energy-efficient hardware architectures for deep and spiking neural networks. The design strategies adopted in this work can be extended to other spike and non-spike based systems for building embedded solutions having power/energy constraints

Contex-aware gestures for mixed-initiative text editings UIs

This is a pre-copyedited, author-produced PDF of an article accepted for publication in Interacting with computers following peer review. The version of record is available online at: http://dx.doi.org/10.1093/iwc/iwu019[EN] This work is focused on enhancing highly interactive text-editing applications with gestures. Concretely, we study Computer Assisted Transcription of Text Images (CATTI), a handwriting transcription system that follows a corrective feedback paradigm, where both the user and the system collaborate efficiently to produce a high-quality text transcription. CATTI-like applications demand fast and accurate gesture recognition, for which we observed that current gesture recognizers are not adequate enough. In response to this need we developed MinGestures, a parametric context-aware gesture recognizer. Our contributions include a number of stroke features for disambiguating copy-mark gestures from handwritten text, plus the integration of these gestures in a CATTI application. It becomes finally possible to create highly interactive stroke-based text-editing interfaces, without worrying to verify the user intent on-screen. We performed a formal evaluation with 22 e-pen users and 32 mouse users using a gesture vocabulary of 10 symbols. MinGestures achieved an outstanding accuracy (<1% error rate) with very high performance (<1 ms of recognition time). We then integrated MinGestures in a CATTI prototype and tested the performance of the interactive handwriting system when it is driven by gestures. Our results show that using gestures in interactive handwriting applications is both advantageous and convenient when gestures are simple but context-aware. Taken together, this work suggests that text-editing interfaces not only can be easily augmented with simple gestures, but also may substantially improve user productivity.This work has been supported by the European Commission through the 7th Framework Program (tranScriptorium: FP7- ICT-2011-9, project 600707 and CasMaCat: FP7-ICT-2011-7, project 287576). It has also been supported by the Spanish MINECO under grant TIN2012-37475-C02-01 (STraDa), and the Generalitat Valenciana under grant ISIC/2012/004 (AMIIS).Leiva, LA.; Alabau, V.; Romero Gómez, V.; Toselli, AH.; Vidal, E. (2015). Contex-aware gestures for mixed-initiative text editings UIs. Interacting with Computers. 27(6):675-696. https://doi.org/10.1093/iwc/iwu019S675696276Alabau V. Leiva L. A. Transcribing Handwritten Text Images with a Word Soup Game. Proc. Extended Abstr. Hum. Factors Comput. Syst. (CHI EA) 2012.Alabau V. Rodríguez-Ruiz L. Sanchis A. Martínez-Gómez P. Casacuberta F. On Multimodal Interactive Machine Translation Using Speech Recognition. Proc. Int. Conf. Multimodal Interfaces (ICMI). 2011a.Alabau V. Sanchis A. Casacuberta F. Improving On-Line Handwritten Recognition using Translation Models in Multimodal Interactive Machine Translation. Proc. Assoc. Comput. Linguistics (ACL) 2011b.Alabau, V., Sanchis, A., & Casacuberta, F. (2014). Improving on-line handwritten recognition in interactive machine translation. Pattern Recognition, 47(3), 1217-1228. doi:10.1016/j.patcog.2013.09.035Anthony L. Wobbrock J. O. A Lightweight Multistroke Recognizer for User Interface Prototypes. Proc. Conf. Graph. Interface (GI). 2010.Anthony L. Wobbrock J. O. N-Protractor: a Fast and Accurate Multistroke Recognizer. Proc. Conf. Graph. Interface (GI) 2012.Anthony L. Vatavu R.-D. Wobbrock J. O. Understanding the Consistency of Users' Pen and Finger Stroke Gesture Articulation. Proc. Conf. Graph. Interface (GI). 2013.Appert C. Zhai S. Using Strokes as Command Shortcuts: Cognitive Benefits and Toolkit Support. Proc. SIGCHI Conf. Hum. Fact. Comput. Syst. (CHI) 2009.Bahlmann C. Haasdonk B. Burkhardt H. On-Line Handwriting Recognition with Support Vector Machines: A Kernel Approach. Proc. Int. Workshop Frontiers Handwriting Recognition (IWFHR). 2001.Bailly G. Lecolinet E. Nigay L. Flower Menus: a New Type of Marking Menu with Large Menu Breadth, within Groups and Efficient Expert Mode Memorization. Proc.Work. Conf. Adv. Vis. Interfaces (AVI) 2008.Balakrishnan R. Patel P. The PadMouse: Facilitating Selection and Spatial Positioning for the Non-Dominant Hand. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI). 1998.Bau O. Mackay W. E. Octopocus: A Dynamic Guide for Learning Gesture-Based Command Sets. Proc. ACM Symp. User Interface Softw. Technol. (UIST) 2008.Belaid A. Haton J. A syntactic approach for handwritten formula recognition. IEEE Trans. Pattern Anal. Mach. Intell. 1984;6:105-111.Bosch V. Bordes-Cabrera I. Munoz P. C. Hernández-Tornero C. Leiva L. A. Pastor M. Romero V. Toselli A. H. Vidal E. Transcribing a XVII Century Handwritten Botanical Specimen Book from Scratch. Proc. Int. Conf. Digital Access Textual Cultural Heritage (DATeCH). 2014.Buxton W. The natural language of interaction: a perspective on non-verbal dialogues. INFOR 1988;26:428-438.Cao X. Zhai S. Modeling Human Performance of Pen Stroke Gestures. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI). 2007.Castro-Bleda M. J. España-Boquera S. Llorens D. Marzal A. Prat F. Vilar J. M. Zamora-Martinez F. Speech Interaction in a Multimodal Tool for Handwritten Text Transcription. Proc. Int. Conf. Multimodal Interfaces (ICMI) 2011.Connell S. D. Jain A. K. Template-based on-line character recognition. Pattern Recognition 2000;34:1-14.Costagliola G. Deufemia V. Polese G. Risi M. A Parsing Technique for Sketch Recognition Systems. Proc. 2004 IEEE Symp. Vis. Lang. Hum. Centric Comput. (VLHCC). 2004.Culotta, A., Kristjansson, T., McCallum, A., & Viola, P. (2006). Corrective feedback and persistent learning for information extraction. Artificial Intelligence, 170(14-15), 1101-1122. doi:10.1016/j.artint.2006.08.001Deepu V. Madhvanath S. Ramakrishnan A. Principal Component Analysis for Online Handwritten Character Recognition. Proc. Int. Conf. Pattern Recognition (ICPR). 2004.Delaye A. Sekkal R. Anquetil E. Continuous Marking Menus for Learning Cursive Pen-Based Gestures. Proc. Int. Conf. Intell. User Interfaces (IUI) 2011.Dimitriadis Y. Coronado J. Towards an art-based mathematical editor that uses on-line handwritten symbol recognition. Pattern Recognition 1995;8:807-822.El Meseery M. El Din M. F. Mashali S. Fayek M. Darwish N. Sketch Recognition Using Particle Swarm Algorithms. Proc. 16th IEEE Int. Conf. Image Process. (ICIP). 2009.Goldberg D. Goodisman A. Stylus User Interfaces for Manipulating Text. Proc. ACM Symp. User Interface Softw. Technol. (UIST) 1991.Goldberg D. Richardson C. Touch-Typing with a Stylus. Proc. INTERCHI'93 Conf. Hum. Factors Comput. Syst. 1993.Stevens, M. E. (1968). Selected pattern recognition projects in Europe. Pattern Recognition, 1(2), 103-118. doi:10.1016/0031-3203(68)90002-2Hardock G. Design Issues for Line Driven Text Editing/ Annotation Systems. Proc. Conf. Graph. Interface (GI). 1991.Hardock G. Kurtenbach G. Buxton W. A Marking Based Interface for Collaborative Writing. Proc.ACM Symp. User Interface Softw. Technol. (UIST) 1993.Hinckley K. Baudisch P. Ramos G. Guimbretiere F. Design and Analysis of Delimiters for Selection-Action Pen Gesture Phrases in Scriboli. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI). 2005.Hong J. I. Landay J. A. SATIN: A Toolkit for Informal Ink-Based Applications. Proc. ACM Symp. User Interface Softw. Technol. (UIST) 2000.Horvitz E. Principles of Mixed-Initiative User Interfaces. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI). 1999.Huerst W. Yang J. Waibel A. Interactive Error Repair for an Online Handwriting Interface. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI) 2010.Jelinek F. Cambridge, Massachusetts: MIT Press; 1998. Statistical Methods for Speech Recognition.Johansson S. Atwell E. Garside R. Leech G. The Tagged LOB Corpus, User's Manual. Norwegian Computing Center for the Humanities. 1996.Karat C.-M. Halverson C. Horn D. Karat J. Patterns of Entry and Correction in Large Vocabulary Continuous Speech Recognition Systems. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI). 1999.Kerrick, D. D., & Bovik, A. C. (1988). Microprocessor-based recognition of handprinted characters from a tablet input. Pattern Recognition, 21(5), 525-537. doi:10.1016/0031-3203(88)90011-8Koschinski M. Winkler H. Lang M. Segmentation and Recognition of Symbols within Handwritten Mathematical Expressions. Proc. IEEE Int. Conf. Acoustics Speech Signal Process. (ICASSP). 1995.Kosmala A. Rigoll G. On-Line Handwritten Formula Recognition Using Statistical Methods. Proc. Int. Conf. Pattern Recognition (ICPR) 1998.Kristensson P. O. Discrete and continuous shape writing for text entry and control. 2007. Ph.D. Thesis, Linköping University, Sweden.Kristensson P. O. Denby L. C. Text Entry Performance of State of the Art Unconstrained Handwriting Recognition: a Longitudinal User Study. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI). 2009.Kristensson P. O. Denby L. C. Continuous Recognition and Visualization of Pen Strokes and Touch-Screen Gestures. Proc. Eighth Eurograph. Symp. Sketch-Based Interfaces Model. (SBIM) 2011.Kristensson P. O. Zhai S. SHARK2: A Large Vocabulary Shorthand Writing System for Pen-Based Computers. Proc. ACM Symp. User Interface Softw. Technol. (UIST). 2004.Kurtenbach G. P. The design and evaluation of marking menus. 1991. Ph.D. Thesis, University of Toronto.Kurtenbach G. P. Buxton W. Issues in Combining Marking and Direct Manipulation Techniques. Proc. ACM Symp. User Interface Softw. Technol. (UIST). 1991.Kurtenbach G. Buxton W. User Learning and Performance with Marking Menus. Proc. Extended Abstr. Hum. Factors Comput. Syst. (CHI EA) 1994.Kurtenbach, G., Sellen, A., & Buxton, W. (1993). An Empirical Evaluation of Some Articulatory and Cognitive Aspects of Marking Menus. Human-Computer Interaction, 8(1), 1-23. doi:10.1207/s15327051hci0801_1LaLomia M. User Acceptance of Handwritten Recognition Accuracy. Proc. Extended Abstr. Hum. Factors Comput. Syst. (CHI EA). 1994.Leiva L. A. Romero V. Toselli A. H. Vidal E. Evaluating an Interactive–Predictive Paradigm on Handwriting Transcription: A Case Study and Lessons Learned. Proc. 35th Annu. IEEE Comput. Softw. Appl. Conf. (COMPSAC) 2011.Leiva L. A. Alabau V. Vidal E. Error-Proof, High-Performance, and Context-Aware Gestures for Interactive Text Edition. Proc. Extended Abstr. Hum. Factors Comput. Syst. (CHI EA). 2013.Li Y. Protractor: A Fast and Accurate Gesture Recognizer. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI) 2010.Li W. Hammond T. Using Scribble Gestures to Enhance Editing Behaviors of Sketch Recognition Systems. Proc. Extended Abstr. Hum. Factors Comput. Syst. (CHI EA). 2012.Liao C. Guimbretière F. Hinckley K. Hollan J. Papiercraft: a gesture-based command system for interactive paper. ACM Trans. Comput.–Hum. Interaction (TOCHI) 2008;14:18:1-18:27.Liu P. Soong F. K. Word Graph Based Speech Rcognition Error Correction by Handwriting Input. Proc. Int. Conf. Multimodal Interfaces (ICMI). 2006.Long A. Landay J. Rowe L. Implications for a Gesture Design Tool. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI) 1999.Long A. C. Jr. Landay J. A. Rowe L. A. Michiels J. Visual Similarity of Pen Gestures. Proc. SIGCHI Conf. Hum. Factors Comput. Syst. (CHI). 2000.MacKenzie, I. S., & Chang, L. (1999). A performance comparison of two handwriting recognizers. Interacting with Computers, 11(3), 283-297. doi:10.1016/s0953-5438(98)00030-7MacKenzie I. S. Tanaka-Ishii K. San Francisco, CA, USA: Morgan Kaufmann Publishers Inc.; 2007. Text Entry Systems: Mobility, Accessibility, Universality.MARTI, U.-V., & BUNKE, H. (2001). USING A STATISTICAL LANGUAGE MODEL TO IMPROVE THE PERFORMANCE OF AN HMM-BASED CURSIVE HANDWRITING RECOGNITION SYSTEM. International Journal of Pattern Recognition and Artificial Intelligence, 15(01), 65-90. doi:10.1142/s0218001401000848Marti, U.-V., & Bunke, H. (2002). The IAM-database: an English sentence database for offline handwriting recognition. International Journal on Document Analysis and Recognition, 5(1), 39-46. doi:10.1007/s100320200071Martín-Albo D. Romero V. Toselli A. H. Vidal E. Multimodal computer-assisted transcription of text images at character-level interaction. Int. J. Pattern Recogn. Artif. Intell. 2012;26:1-19.Marzinkewitsch R. Operating Computer Algebra Systems by Hand-Printed Input. Proc. Int. Symp. Symbolic Algebr. Comput. (ISSAC). 1991.Mas, J., Llados, J., Sanchez, G., & Jorge, J. A. P. (2010). A syntactic approach based on distortion-tolerant Adjacency Grammars and a spatial-directed parser to interpret sketched diagrams. Pattern Recognition, 43(12), 4148-4164. doi:10.1016/j.patcog.2010.07.003Moyle M. Cockburn A. Analysing Mouse and Pen Flick Gestures. Proc. SIGCHI-NZ Symp. Comput.–Hum. Interact. (CHINZ). 2002.Nakayama Y. A Prototype Pen-Input Mathematical Formula Editor. Proc. AACE EdMedia 1993.Ogata J. Goto M. Speech Repair: Quick Error Correction Just by Using Selection Operation for Speech Input Interface. Proc. Eurospeech. 2005.Ortiz-Martínez D. Leiva L. A. Alabau V. Casacuberta F. Interactive Machine Translation using a Web-Based Architecture. Proc. Int. Conf. Intell. User Interfaces (IUI) 2010.Ortiz-Martínez D. Leiva L. A. Alabau V. García-Varea I. Casacuberta F. An Interactive Machine Translation System with Online Learning. Proc. Assoc. Comput. Linguist. (ACL). 2011.Michael Powers, V. (1973). Pen direction sequences in character recognition. Pattern Recognition, 5(4), 291-302. doi:10.1016/0031-3203(73)90022-8Raab F. Extremely efficient menu selection: Marking menus for the Flash platform. 2009. Available at http://www.betriebsraum.de/blog/2009/07/21/efficient-gesture-recognition-and-corner-finding-in-as3/ (retrieved on May 2012).Revuelta-Martínez A. Rodríguez L. García-Varea I. A Computer Assisted Speech Transcription System. Proc. Eur. Chap. Assoc. Comput. Linguist. (EACL). 2012.Revuelta-Martínez, A., Rodríguez, L., García-Varea, I., & Montero, F. (2013). Multimodal interaction for information retrieval using natural language. Computer Standards & Interfaces, 35(5), 428-441. doi:10.1016/j.csi.2012.11.002Rodríguez L. García-Varea I. Revuelta-Martínez A. Vidal E. A Multimodal Interactive Text Generation System. Proc. Int. Conf. Multimodal Interfaces Workshop Mach. Learn. Multimodal Interact. (ICMI-MLMI). 2010a.Rodríguez L. García-Varea I. Vidal E. Multi-Modal Computer Assisted Speech Transcription. Proc. Int. Conf. Multimodal Interfaces Workshop Mach. Learn. Multimodal Interact. (ICMI-MLMI) 2010b.Romero V. Leiva L. A. Toselli A. H. Vidal E. Interactive Multimodal Transcription of Text Images using a Web-Based Demo System. Proc. Int. Conf. Intell. User Interfaces (IUI). 2009a.Romero V. Toselli A. H. Vidal E. Using Mouse Feedback in Computer Assisted Transcription of Handwritten Text Images. Proc. Int. Conf. Doc. Anal. Recogn. (ICDAR) 2009b.Romero V. Toselli A. H. Vidal E. Study of Different Interactive Editing Operations in an Assisted Transcription System. Proc. Int. Conf. Multimodal Interfaces (ICMI). 2011.Romero V. Toselli A. H. Vidal E. Vol. 80. Singapore: World Scientific Publishing Company; 2012. Multimodal Interactive Handwritten Text Transcription.Rubine, D. (1991). Specifying gestures by example. ACM SIGGRAPH Computer Graphics, 25(4), 329-337. doi:10.1145/127719.122753Rubine D. H. 1991b. The automatic recognition of gestures. Ph.D. Thesis, Carnegie Mellon University.Sánchez-Sáez R. Leiva L. A. Sánchez J. A. Benedí J. M. Interactive Predictive Parsing using a Web-Based Architecture. Proc. North Am. Chap. Assoc. Comput. Linguist. 2010.Saund E. Fleet D. Larner D. Mahoney J. Perceptually-Supported Image Editing of Text and Graphics. Proc. ACM Symp. User Interface Softw. Technol. (UIST) 2003.Shilman M. Tan D. S. Simard P. CueTIP: a Mixed-Initiative Interface for Correcting Handwriting Errors. Proc. ACM Symp. User Interface Softw. Technol. (UIST). 2006.Signer B. Kurmann U. Norrie M. C. igesture: A General Gesture Recognition Framework. Proc. Int. Conf. Doc. Anal. Recogn. (ICDAR) 2007.Smithies S. Novins K. Arvo J. A handwriting-based equation editor. Proc. Conf. Graph. Interface (GI). 1999.Suhm, B., Myers, B., & Waibel, A. (2001). Multimodal error correction for speech user interfaces. ACM Transactions on Computer-Human Interaction, 8(1), 60-98. doi:10.1145/371127.371166Tappert C. C. Mosley P. H. Recent advances in pen computing. 2001. Technical Report 166, Pace University, available: http://support.csis.pace.edu.Toselli, A. H., Romero, V., Pastor, M., & Vidal, E. (2010). Multimodal interactive transcription of text images. Pattern Recognition, 43(5), 1814-1825. doi:10.1016/j.patcog.2009.11.019Toselli A. H. Vidal E. Casacuberta F. , editors. Berlin, Heidelberg, New York: Springer; 2011. Multimodal-Interactive Pattern Recognition and Applications.Tseng S. Fogg B. Credibility and computing technology. Commun. ACM 1999;42:39-44.Vatavu R.-D. Anthony L. Wobbrock J. O. Gestures as Point Clouds: A P Recognizer for User Interface Prototypes. Proc. Int. Conf. Multimodal Interfaces (ICMI). 2012.Vertanen K. Kristensson P. O. Parakeet: A Continuous Speech Recognition System for Mobile Touch-Screen Devices. Proc. Int. Conf. Intell. User Interfaces (IUI) 2009.Vidal E. Rodríguez L. Casacuberta F. García-Varea I. Mach. Learn. Multimodal Interact., Lect. Notes Comput. Sci. Vol. 4892. Berlin, Heidelberg: Springer; 2008. Interactive Pattern Recognition.Wang X. Li J. Ao X. Wang G. Dai G. Multimodal Error Correction for Continuous Handwriting Recognition in Pen-Based User Interfaces. Proc. Int. Conf. Intell. User Interfaces (IUI). 2006.Wang L. Hu T. Liu P. Soong F. K. Efficient Handwriting Correction of Speech Recognition Errors with Template Constrained Posterior (TCP). Proc. INTERSPEECH 2008.Wobbrock J. O. Wilson A. D. Li Y. Gestures without Libraries, Toolkits or Training: A $1 Recognizer for User Interface Prototypes. Proc. ACM Symp. User Interface Softw. Technol. (UIST). 2007.Wolf C. G. Morrel-Samuels P. The use of hand-drawn gestures for text editing. Int. J. Man–Mach. Stud. 1987;27:91-102.Zeleznik R. Miller T. Fluid Inking: Augmenting the Medium of Free-Form Inking with Gestures. Proc. Conf. Graph. Interface (GI). 2006.Yong Zhang, McCullough, C., Sullins, J. R., & Ross, C. R. (2010). Hand-Drawn Face Sketch Recognition by Humans and a PCA-Based Algorithm for Forensic Applications. IEEE Transactions on Systems, Man, and Cybernetics - Part A: Systems and Humans, 40(3), 475-485. doi:10.1109/tsmca.2010.2041654Zhao S. Balakrishnan R. Simple vs. Compound Mark Hierarchical Marking Menus. Proc. ACM Symp. User Interface Softw. Technol. (UIST) 2004

Multimodal Interactive Transcription of Handwritten Text Images

En esta tesis se presenta un nuevo marco interactivo y multimodal para la transcripción de Documentos manuscritos. Esta aproximación, lejos de proporcionar la transcripción completa pretende asistir al experto en la dura tarea de transcribir. Hasta la fecha, los sistemas de reconocimiento de texto manuscrito disponibles no proporcionan transcripciones aceptables por los usuarios y, generalmente, se requiere la intervención del humano para corregir las transcripciones obtenidas. Estos sistemas han demostrado ser realmente útiles en aplicaciones restringidas y con vocabularios limitados (como es el caso del reconocimiento de direcciones postales o de cantidades numéricas en cheques bancarios), consiguiendo en este tipo de tareas resultados aceptables. Sin embargo, cuando se trabaja con documentos manuscritos sin ningún tipo de restricción (como documentos manuscritos antiguos o texto espontáneo), la tecnología actual solo consigue resultados inaceptables. El escenario interactivo estudiado en esta tesis permite una solución más efectiva. En este escenario, el sistema de reconocimiento y el usuario cooperan para generar la transcripción final de la imagen de texto. El sistema utiliza la imagen de texto y una parte de la transcripción previamente validada (prefijo) para proponer una posible continuación. Despues, el usuario encuentra y corrige el siguente error producido por el sistema, generando así un nuevo prefijo mas largo. Este nuevo prefijo, es utilizado por el sistema para sugerir una nueva hipótesis. La tecnología utilizada se basa en modelos ocultos de Markov y n-gramas. Estos modelos son utilizados aquí de la misma manera que en el reconocimiento automático del habla. Algunas modificaciones en la definición convencional de los n-gramas han sido necesarias para tener en cuenta la retroalimentación del usuario en este sistema.Romero Gómez, V. (2010). Multimodal Interactive Transcription of Handwritten Text Images [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8541Palanci

Constraint-free Natural Image Reconstruction from fMRI Signals Based on Convolutional Neural Network

In recent years, research on decoding brain activity based on functional magnetic resonance imaging (fMRI) has made remarkable achievements. However, constraint-free natural image reconstruction from brain activity is still a challenge. The existing methods simplified the problem by using semantic prior information or just reconstructing simple images such as letters and digitals. Without semantic prior information, we present a novel method to reconstruct nature images from fMRI signals of human visual cortex based on the computation model of convolutional neural network (CNN). Firstly, we extracted the units output of viewed natural images in each layer of a pre-trained CNN as CNN features. Secondly, we transformed image reconstruction from fMRI signals into the problem of CNN feature visualizations by training a sparse linear regression to map from the fMRI patterns to CNN features. By iteratively optimization to find the matched image, whose CNN unit features become most similar to those predicted from the brain activity, we finally achieved the promising results for the challenging constraint-free natural image reconstruction. As there was no use of semantic prior information of the stimuli when training decoding model, any category of images (not constraint by the training set) could be reconstructed theoretically. We found that the reconstructed images resembled the natural stimuli, especially in position and shape. The experimental results suggest that hierarchical visual features can effectively express the visual perception process of human brain

Live Streaming Speech Recognition Using Deep Bidirectional LSTM Acoustic Models and Interpolated Language Models

[EN] Although Long-Short Term Memory (LSTM) networks and deep Transformers are now extensively used in offline ASR, it is unclear how best offline systems can be adapted to work with them under the streaming setup. After gaining considerable experience on this regard in recent years, in this paper we show how an optimized, low-latency streaming decoder can be built in which bidirectional LSTM acoustic models, together with general interpolated language models, can be nicely integrated with minimal performance degradation. In brief, our streaming decoder consists of a one-pass, real-time search engine relying on a limited-duration window sliding over time and a number of ad hoc acoustic and language model pruning techniques. Extensive empirical assessment is provided on truly streaming tasks derived from the well-known LibriSpeech and TED talks datasets, as well as from TV shows on a main Spanish broadcasting station.This work was supported in part by European Union's Horizon 2020 Research and Innovation Programme under Grant 761758 (X5gon), and 952215 (TAILOR) and Erasmus+ Education Program under Grant Agreement 20-226-093604-SCH, in part by MCIN/AEI/10.13039/501100011033 ERDF A way of making Europe under Grant RTI2018-094879-B-I00, and in part by Generalitat Valenciana's Research Project Classroom Activity Recognition under Grant PROMETEO/2019/111. Funding for open access charge: CRUE-Universitat Politecnica de Valencia. The associate editor coordinating the review of this manuscript and approving it for publication was Prof. Lei Xie.Jorge-Cano, J.; Giménez Pastor, A.; Silvestre Cerdà, JA.; Civera Saiz, J.; Sanchis Navarro, JA.; Juan, A. (2022). Live Streaming Speech Recognition Using Deep Bidirectional LSTM Acoustic Models and Interpolated Language Models. IEEE/ACM Transactions on Audio Speech and Language Processing. 30:148-161. https://doi.org/10.1109/TASLP.2021.3133216S1481613