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Ventral and dorsal pathways for language

Saur, Dorothee; Kreher, Björn W.; Schnell, Susanne; Kümmerer, Dorothee; Kellmeyer, Philipp; Vry, Magnus-Sebastian; Umarova, Roza; Musso, Mariacristina; Glauche, Volkmar; Abel, Stefanie; Huber, Walter; Rijntjes, Michel; Hennig, Jürgen; Weiller, Corneliu
Fonte: National Academy of Sciences Publicador: National Academy of Sciences
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
314.5802%
Built on an analogy between the visual and auditory systems, the following dual stream model for language processing was suggested recently: a dorsal stream is involved in mapping sound to articulation, and a ventral stream in mapping sound to meaning. The goal of the study presented here was to test the neuroanatomical basis of this model. Combining functional magnetic resonance imaging (fMRI) with a novel diffusion tensor imaging (DTI)-based tractography method we were able to identify the most probable anatomical pathways connecting brain regions activated during two prototypical language tasks. Sublexical repetition of speech is subserved by a dorsal pathway, connecting the superior temporal lobe and premotor cortices in the frontal lobe via the arcuate and superior longitudinal fascicle. In contrast, higher-level language comprehension is mediated by a ventral pathway connecting the middle temporal lobe and the ventrolateral prefrontal cortex via the extreme capsule. Thus, according to our findings, the function of the dorsal route, traditionally considered to be the major language pathway, is mainly restricted to sensory-motor mapping of sound to articulation, whereas linguistic processing of sound to meaning requires temporofrontal interaction transmitted via the ventral route.

Parallel versus serial processing dependencies in the perisylvian speech network: A Granger analysis of intracranial EEG data

Gow, David W.; Keller, Corey J.; Eskandar, Emand; Meng, Nate; Cash, Sydney S.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
299.53633%
In this work, we apply Granger causality analysis to high spatiotemporal resolution intracranial EEG (iEEG) data to examine how different components of the left perisylvian language network interact during spoken language perception. The specific focus is on the characterization of serial versus parallel processing dependencies in the dominant hemisphere dorsal and ventral speech processing streams. Analysis of iEEG data from a large, 64-electrode grid implanted over the left perisylvian region in a single right-handed patient showed a consistent pattern of direct posterior superior temporal gyrus influence over sites distributed over the entire ventral pathway for words, nonwords, and phonetically ambiguous items that could be interpreted either as words or nonwords. For the phonetically ambiguous items, this pattern was overlayed by additional dependencies involving the inferior frontal gyrus, which influenced activation measured at electrodes located in both ventral and dorsal stream speech structures. Implications of these results for understanding the functional architecture of spoken language processing and interpreting the role of the posterior superior temporal gyrus in speech perception are discussed.

From Acoustic Segmentation to Language Processing: Evidence from Optical Imaging

Obrig, Hellmuth; Rossi, Sonja; Telkemeyer, Silke; Wartenburger, Isabell
Fonte: Frontiers Research Foundation Publicador: Frontiers Research Foundation
Tipo: Artigo de Revista Científica
Publicado em 23/06/2010 EN
Relevância na Pesquisa
315.10836%
During language acquisition in infancy and when learning a foreign language, the segmentation of the auditory stream into words and phrases is a complex process. Intuitively, learners use “anchors” to segment the acoustic speech stream into meaningful units like words and phrases. Regularities on a segmental (e.g., phonological) or suprasegmental (e.g., prosodic) level can provide such anchors. Regarding the neuronal processing of these two kinds of linguistic cues a left-hemispheric dominance for segmental and a right-hemispheric bias for suprasegmental information has been reported in adults. Though lateralization is common in a number of higher cognitive functions, its prominence in language may also be a key to understanding the rapid emergence of the language network in infants and the ease at which we master our language in adulthood. One question here is whether the hemispheric lateralization is driven by linguistic input per se or whether non-linguistic, especially acoustic factors, “guide” the lateralization process. Methodologically, functional magnetic resonance imaging provides unsurpassed anatomical detail for such an enquiry. However, instrumental noise, experimental constraints and interference with EEG assessment limit its applicability...

Object recognition in Williams syndrome: Uneven ventral stream activation

O’Hearn, Kirsten; Roth, Jennifer K.; Courtney, Susan M.; Luna, Beatriz; Street, Whitney; Terwillinger, Robert; Landau, Barbara
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
295.45602%
Williams syndrome (WS) is a genetic disorder associated with severe visuospatial deficits, relatively strong language skills, heightened social interest, and increased attention to faces. On the basis of the visuospatial impairments, this disorder has been characterized primarily as a deficit of the dorsal stream, the occipitoparietal brain regions that subserve visuospatial processing. However, some evidence indicates that this disorder may also affect the development of the ventral stream, the occipitotemporal cortical regions that subserve face and object recognition. The present studies examined ventral stream function in WS, with the hypothesis that faces would produce a relatively more mature pattern of ventral occipitotemporal cortical activation, relative to other objects that are also represented across these visual areas. We compared functional magnetic resonance imaging activation patterns during viewing of human faces, cat faces, houses and shoes in individuals with WS (age 14–27), typically developing 6–9 year olds (matched approximately on mental age), and typically developing 14–26 year olds (matched on chronological age). Typically developing individuals exhibited changes in the pattern of activation over age...

White matter anisotropy in the ventral language pathway predicts sound-to-word learning success

Wong, Francis C. K.; Chandrasekaran, Bharath; Garibaldi, Kyla; Wong, Patrick C. M.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 15/06/2011 EN
Relevância na Pesquisa
313.575%
According to the dual stream model of auditory language processing, the dorsal stream is responsible for mapping sound to articulation while the ventral stream plays the role of mapping sound to meaning. Most researchers agree that the arcuate fasciculus (AF) is the neuroanatomical correlate of the dorsal steam, however, less is known about what constitutes the ventral one. Nevertheless two hypotheses exist, one suggests that the segment of the AF that terminates in middle temporal gyrus corresponds to the ventral stream and the other suggests that it is the extreme capsule that underlies this sound to meaning pathway. The goal of this study is to evaluate these two competing hypotheses. We trained participants with a sound-to-word learning paradigm in which they learned to use a foreign phonetic contrast for signaling word meaning. Using diffusion tensor imaging (DTI), a brain imaging tool to investigate white matter connectivity in humans, we found that fractional anisotropy in the left parietal-temporal region positively correlated with the performance in sound-to-word learning. In addition, fiber tracking revealed a ventral pathway, composed of the extreme capsule and the inferior longitudinal fasciculus, that mediated auditory comprehension. Our findings provide converging evidence supporting the importance of the ventral steam...

Damage to ventral and dorsal language pathways in acute aphasia

Kümmerer, Dorothee; Hartwigsen, Gesa; Kellmeyer, Philipp; Glauche, Volkmar; Mader, Irina; Klöppel, Stefan; Suchan, Julia; Karnath, Hans-Otto; Weiller, Cornelius; Saur, Dorothee
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica
EN
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302.37043%
Converging evidence from neuroimaging studies and computational modelling suggests an organization of language in a dual dorsal–ventral brain network: a dorsal stream connects temporoparietal with frontal premotor regions through the superior longitudinal and arcuate fasciculus and integrates sensorimotor processing, e.g. in repetition of speech. A ventral stream connects temporal and prefrontal regions via the extreme capsule and mediates meaning, e.g. in auditory comprehension. The aim of our study was to test, in a large sample of 100 aphasic stroke patients, how well acute impairments of repetition and comprehension correlate with lesions of either the dorsal or ventral stream. We combined voxelwise lesion-behaviour mapping with the dorsal and ventral white matter fibre tracts determined by probabilistic fibre tracking in our previous study in healthy subjects. We found that repetition impairments were mainly associated with lesions located in the posterior temporoparietal region with a statistical lesion maximum in the periventricular white matter in projection of the dorsal superior longitudinal and arcuate fasciculus. In contrast, lesions associated with comprehension deficits were found more ventral-anterior in the temporoprefrontal region with a statistical lesion maximum between the insular cortex and the putamen in projection of the ventral extreme capsule. Individual lesion overlap with the dorsal fibre tract showed a significant negative correlation with repetition performance...

Dynamic Processing in the Human Language System: Synergy between the Arcuate Fascicle and Extreme Capsule

Rolheiser, Tyler; Stamatakis, Emmanuel A.; Tyler, Lorraine K.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 23/11/2011 EN
Relevância na Pesquisa
314.09766%
The production and comprehension of human language is thought to involve a network of frontal, parietal, and temporal cortical loci interconnected by two dominant white matter pathways. These two white matter bundles, often referred to as the dorsal and ventral processing tracts, are hypothesized to have markedly different language functions. The dorsal tract is thought to process phonological processing, while the ventral tract is considered to abet semantics. This proposed functional differentiation of tracts is similar to the ventral and dorsal dichotomy proposed for the visual and auditory systems. The present study evaluated this characterization of the language system in the context of various components involved in its function. Twenty-four chronic stroke patients completed a battery of 10 language tests designed to measure performance on the comprehension and production of phonology, morphology, semantics, and syntax. The patients also completed diffusion MRI scanning. Lesions were confined to the left hemisphere, but the size and location of the insult varied so that patients had damage to a single tract, both tracts, or neither tract. Individual FA maps were generated, and focal areas of hypointensity served as markers of white matter damage. Whole-brain voxel-by-voxel correlations revealed that only phonological and semantic tasks fit into the dual-stream model...

Cracking the Language Code: Neural Mechanisms Underlying Speech Parsing

McNealy, Kristin; Mazziotta, John C.; Dapretto, Mirella
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em 19/07/2006 EN
Relevância na Pesquisa
304.18285%
Word segmentation, detecting word boundaries in continuous speech, is a critical aspect of language learning. Previous research in infants and adults demonstrated that a stream of speech can be readily segmented based solely on the statistical and speech cues afforded by the input. Using functional magnetic resonance imaging (fMRI), the neural substrate of word segmentation was examined on-line as participants listened to three streams of concatenated syllables, containing either statistical regularities alone, statistical regularities and speech cues, or no cues. Despite the participants’ inability to explicitly detect differences between the speech streams, neural activity differed significantly across conditions, with left-lateralized signal increases in temporal cortices observed only when participants listened to streams containing statistical regularities, particularly the stream containing speech cues. In a second fMRI study, designed to verify that word segmentation had implicitly taken place, participants listened to trisyllabic combinations that occurred with different frequencies in the streams of speech they just heard (“words,” 45 times; “partwords,” 15 times; “nonwords,” once). Reliably greater activity in left inferior and middle frontal gyri was observed when comparing words with partwords and...

Inferring Speaker Affect in Spoken Natural Language Communication

Pon-Barry, Heather Roberta
Fonte: Harvard University Publicador: Harvard University
Tipo: Thesis or Dissertation
EN_US
Relevância na Pesquisa
396.55625%
The field of spoken language processing is concerned with creating computer programs that can understand human speech and produce human-like speech. Regarding the problem of understanding human speech, there is currently growing interest in moving beyond speech recognition (the task of transcribing the words in an audio stream) and towards machine listening—interpreting the full spectrum of information in an audio stream. One part of machine listening, the problem that this thesis focuses on, is the task of using information in the speech signal to infer a person’s emotional or mental state. In this dissertation, our approach is to assess the utility of prosody, or manner of speaking, in classifying speaker affect. Prosody refers to the acoustic features of natural speech: rhythm, stress, intonation, and energy. Affect refers to a person’s emotions and attitudes such as happiness, frustration, or uncertainty. We focus on one specific dimension of affect: level of certainty. Our goal is to automatically infer whether a person is confident or uncertain based on the prosody of his or her speech. Potential applications include conversational dialogue systems (e.g., in educational technology) and voice search (e.g., smartphone personal assistants). There are three main contributions of this thesis. The first contribution is a method for eliciting uncertain speech that binds a speaker’s uncertainty to a single phrase within the larger utterance...

StreamIt: A Language and Compiler for Communication-Exposed Architectures

Thies, William; Gordon, Michael I.; Karczmarek, Michal; Maze, David; Amarasinghe, Saman P.
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
Tipo: Artigo de Revista Científica Formato: 726684 bytes; application/pdf
EN_US
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316.02938%
With the increasing miniaturization of transistors, wire delays are becoming a dominant factor in microprocessor performance. To address this issue, a number of emerging architectures contain replicated processing units with software-exposed communication between one unit and another (e.g., Raw, SmartMemories, TRIPS). However, for their use to be widespread, it will be necesary to develop a common machine language to allow programmers to express an algorithm in a way that can be efficiently mapped across these architectures. We propose a new common machine language for grid-based software-exposed architectures: StreamIt. StreamIt is a high-level programming language with explicit support for streaming computation. Unlike sequential programs with obscured dependence information and complex communication patterns, a stream program is naturally written as a set of concurrent filters with regular steady-state communication. The language imposes a hierarchical structure on the stream graph that enables novel representations and optimizations within the StreamIt compiler. We have implemented a fully functional compiler that parallelizes StreamIt applications for Raw, including several load-balancing transformations. Though StreamIt exposes the parallelism and communication patterns of stream programs...

Cache optimizations for stream programs

Sermuliņš, Jānis
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 75 leaves; 3129060 bytes; 3132114 bytes; application/pdf; application/pdf
ENG
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As processor speeds continue to increase, the memory bottleneck remains a primary impediment to attaining performance. Effective use of the memory hierarchy can result in significant performance gains. This thesis focuses on a set of transformations that either reduce cache-miss rate or reduce the number of memory accesses for the class of streaming applications, which are becoming increasingly prevalent in embedded, desktop and high-performance processing. A fully automated optimization algorithm is presented that reduces the memory bottleneck for stream applications developed in the high-level stream programming language StreamIt. This thesis presents four memory optimizations: 1) cache aware fusion, which combines adjacent program components while respecting instruction and data cache constraints, 2) execution scaling, which judiciously repeats execution of program components to improve instruction and state locality, 3) scalar replacement, which converts certain data buffers into a sequence of scalar variables that can be register allocated, and 4) optimized buffer management, which reduces the overall number of memory accesses issued by the program. The cache aware fusion and execution scaling reduce the instruction and data cache-miss rates and are founded upon a simple and intuitive cache model that quantifies the temporal locality for a sequence of actor executions.; (cont.) The scalar replacement and optimized buffer management reduce the number of memory accesses. An experimental evaluation of the memory optimizations is presented for three different architectures: StrongARM 1110...

Stream programming for image and video compression

Drake, Matthew Henry
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 108 p.
ENG
Relevância na Pesquisa
304.27785%
Video playback devices rely on compression algorithms to minimize storage, transmission bandwidth, and overall cost. Compression techniques have high realtime and sustained throughput requirements, and the end of CPU clock scaling means that parallel implementations for novel system architectures are needed. Parallel implementations increase the complexity of application design. Current languages force the programmer to trade off productivity for performance; the performance demands dictate that the parallel programmer choose a low-level language in which he can explicitly control the degree of parallelism and tune his code for performance. This methodology is not cost effective because this architecture-specific code is neither malleable nor portable. Reimplementations must be written from scratch for each of the existing parallel and reconfigurable architectures. This thesis shows that multimedia compression algorithms, composed of many independent processing stages, are a good match for the streaming model of computation. Stream programming models afford certain advantages in terms of programmability, robustness, and achieving high performance.; (cont.) This thesis intends to influence language design towards the inclusion of features that lend to the efficient implementation and parallel execution of streaming applications like image and video compression algorithms. Towards this I contribute i) a clean...

Investigation of the dorsal stream hypothesis in Williams syndrome

Bernardino, Inês
Fonte: Universidade de Coimbra Publicador: Universidade de Coimbra
Tipo: Tese de Doutorado
ENG
Relevância na Pesquisa
322.0856%
O Síndrome de Williams (SW) é uma perturbação genética rara do neurodesenvolvimento caracterizada por alterações sensoriais, cognitivas e neuroanatómicas. Esta patologia constitui, por isso, um modelo ímpar para investigar a natureza modular (ou não) dos processos cognitivos, dado que proporciona uma oportunidade rara de estudo das relações entre genes, cérebro e comportamento. O SW tem suscitado interesse no domínio das neurociências cognitivas, devido ao seu perfil cognitivo peculiar, caracterizado por funções preservadas no domínio da linguagem e do reconhecimento facial em oposição a consideráveis défices de coerência visual e de perceção visuo-espacial. No SW verifica-se um viés a favor do processamento visual local, falhando ao mesmo tempo na integração desta informação local que é determinante para a perceção de coerência global. Estas dissociações funcionais no domínio cognitivo têm sido estudadas a par com dissociações ao nível do funcionamento neuronal particularmente no que diz respeito às vias de processamento visual dorsal e ventral. Contudo, o debate persiste e os correlatos neuroanatómicos e neurofisiológicos destes défices não estão ainda estabelecidos. O foco desta tese prende-se com a investigação de múltiplos níveis de processamento visual associados às vias dorsal e ventral no SW...

WaveScript: A Case-Study in Applying a Distributed Stream-Processing Language

Newton, Ryan; Girod, Lewis; Craig, Michael; Madden, Sam; Morrisett, Greg
Fonte: MIT - Massachusetts Institute of Technology Publicador: MIT - Massachusetts Institute of Technology
Formato: 11 p.
Relevância na Pesquisa
510.91%
Applications that combine live data streams with embedded, parallel,and distributed processing are becoming more commonplace. WaveScriptis a domain-specific language that brings high-level, type-safe,garbage-collected programming to these domains. This is made possibleby three primary implementation techniques. First, we employ a novelevaluation strategy that uses a combination of interpretation andreification to partially evaluate programs into stream dataflowgraphs. Second, we use profile-driven compilation to enable manyoptimizations that are normally only available in the synchronous(rather than asynchronous) dataflow domain. Finally, we incorporatean extensible system for rewrite rules to capture algebraic propertiesin specific domains (such as signal processing).We have used our language to build and deploy a sensor-network for theacoustic localization of wild animals, in particular, theYellow-Bellied marmot. We evaluate WaveScript's performance on thisapplication, showing that it yields good performance on both embeddedand desktop-class machines, including distributed execution andsubstantial parallel speedups. Our language allowed us to implementthe application rapidly, while outperforming a previous Cimplementation by over 35%...

The frequency modulated auditory evoked response (FMAER), a technical advance for study of childhood language disorders: cortical source localization and selected case studies

Duffy, Frank H; Eksioglu, Yaman Z; Rotenberg, Alexander; Madsen, Joseph R; Shankardass, Aditi; Als, Heidelise
Fonte: BioMed Central Publicador: BioMed Central
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
403.0885%
Background: Language comprehension requires decoding of complex, rapidly changing speech streams. Detecting changes of frequency modulation (FM) within speech is hypothesized as essential for accurate phoneme detection, and thus, for spoken word comprehension. Despite past demonstration of FM auditory evoked response (FMAER) utility in language disorder investigations, it is seldom utilized clinically. This report's purpose is to facilitate clinical use by explaining analytic pitfalls, demonstrating sites of cortical origin, and illustrating potential utility. Results: FMAERs collected from children with language disorders, including Developmental Dysphasia, Landau-Kleffner syndrome (LKS), and autism spectrum disorder (ASD) and also normal controls - utilizing multi-channel reference-free recordings assisted by discrete source analysis - provided demonstratrions of cortical origin and examples of clinical utility. Recordings from inpatient epileptics with indwelling cortical electrodes provided direct assessment of FMAER origin. The FMAER is shown to normally arise from bilateral posterior superior temporal gyri and immediate temporal lobe surround. Childhood language disorders associated with prominent receptive deficits demonstrate absent left or bilateral FMAER temporal lobe responses. When receptive language is spared...

Faster Sound Stream Segmentation in Musicians than in Nonmusicians

François, Clément; Jaillet, Florent; Takerkart, Sylvain; Schön, Daniele
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 11/07/2014 EN
Relevância na Pesquisa
297.0809%
The musician's brain is considered as a good model of brain plasticity as musical training is known to modify auditory perception and related cortical organization. Here, we show that music-related modifications can also extend beyond motor and auditory processing and generalize (transfer) to speech processing. Previous studies have shown that adults and newborns can segment a continuous stream of linguistic and non-linguistic stimuli based only on probabilities of occurrence between adjacent syllables, tones or timbres. The paradigm classically used in these studies consists of a passive exposure phase followed by a testing phase. By using both behavioural and electrophysiological measures, we recently showed that adult musicians and musically trained children outperform nonmusicians in the test following brief exposure to an artificial sung language. However, the behavioural test does not allow for studying the learning process per se but rather the result of the learning. In the present study, we analyze the electrophysiological learning curves that are the ongoing brain dynamics recorded as the learning is taking place. While musicians show an inverted U shaped learning curve, nonmusicians show a linear learning curve. Analyses of Event-Related Potentials (ERPs) allow for a greater understanding of how and when musical training can improve speech segmentation. These results bring evidence of enhanced neural sensitivity to statistical regularities in musicians and support the hypothesis of positive transfer of training effect from music to sound stream segmentation in general.

Design and Evaluation of a Compiler for Embedded Stream Programs

Newton, Ryan R.; Girod, Lewis D.; Craig, Michael B.; Madden, Samuel R.; Morrisett, John Gregory
Fonte: Association for Computing Machinery Publicador: Association for Computing Machinery
Tipo: Conference Paper
EN_US
Relevância na Pesquisa
616.72418%
Applications that combine live data streams with embedded, parallel, and distributed processing are becoming more commonplace. WaveScript is a domain-specific language that brings high-level, type-safe, garbage-collected programming to these domains. This is made possible by three primary implementation techniques, each of which leverages characteristics of the streaming domain. First, we employ a novel evaluation strategy that uses a combination of interpretation and reification to partially evaluate programs into stream dataflow graphs. Second, we use profile-driven compilation to enable many optimizations that are normally only available in the synchronous (rather than asynchronous) dataflow domain. Finally, we incorporate an extensible system for rewrite rules to capture algebraic properties in specific domains (such as signal processing). We have used our language to build and deploy a sensornetwork for the acoustic localization of wild animals, in particular, the Yellow-Bellied marmot. We evaluate WaveScript's performance on this application, showing that it yields good performance on both embedded and desktop-class machines, including distributed execution and substantial parallel speedups. Our language allowed us to implement the application rapidly...

Consistent Streaming Through Time: A Vision for Event Stream Processing

Barga, Roger S.; Goldstein, Jonathan; Ali, Mohamed; Hong, Mingsheng
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 21/12/2006
Relevância na Pesquisa
406.1962%
Event processing will play an increasingly important role in constructing enterprise applications that can immediately react to business critical events. Various technologies have been proposed in recent years, such as event processing, data streams and asynchronous messaging (e.g. pub/sub). We believe these technologies share a common processing model and differ only in target workload, including query language features and consistency requirements. We argue that integrating these technologies is the next step in a natural progression. In this paper, we present an overview and discuss the foundations of CEDR, an event streaming system that embraces a temporal stream model to unify and further enrich query language features, handle imperfections in event delivery and define correctness guarantees. We describe specific contributions made so far and outline next steps in developing the CEDR system.; Comment: This article is published under a Creative Commons License Agreement (http://creativecommons.org/licenses/by/2.5/.) You may copy, distribute, display, and perform the work, make derivative works and make commercial use of the work, but, you must attribute the work to the author and CIDR 2007. 3rd Biennial Conference on Innovative Data Systems Research (CIDR) January 710...

Assembling Actor-based Mind-Maps from Text Stream

Brucks, Claudine; Schommer, Christoph
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 25/10/2008
Relevância na Pesquisa
372.5403%
For human beings, the processing of text streams of unknown size leads generally to problems because e.g. noise must be selected out, information be tested for its relevance or redundancy, and linguistic phenomenon like ambiguity or the resolution of pronouns be advanced. Putting this into simulation by using an artificial mind-map is a challenge, which offers the gate for a wide field of applications like automatic text summarization or punctual retrieval. In this work we present a framework that is a first step towards an automatic intellect. It aims at assembling a mind-map based on incoming text streams and on a subject-verb-object strategy, having the verb as an interconnection between the adjacent nouns. The mind-map's performance is enriched by a pronoun resolution engine that bases on the work of D. Klein, and C. D. Manning.; Comment: 12 pages, 8 Figures

Mobile to cloud co-processing of ASL finger spelling to text conversion

Hays, Philip
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
404.0256%
Computer recognition of American Sign Language (ASL) is a computationally intensive task. Although it has generally been performed using powerful lab workstations, this research investigates transcription of static ASL signs using an application on a consumer-level mobile device. The application provides real-time sign to text translation by processing a live video stream to detect the ASL alphabet as well as custom signs to perform tasks on the device. In this work several avenues for classification and processing were ex-plored to evaluate performance for mobile ASL transcription. The cho-sen classification algorithm uses locality preserving projections (LPP) with trained support vector machines (SVMs). Processing was investigated using either the mobile device only or with cloud assistance. In comparison to the native mobile application, the cloud-assisted application increased classification speed, reduced memory usage, and kept the network usage low while barely increasing the power required. A distributed solution has been created that will provide a new way of interacting with the mobile device in a native way to a hard-of-hearing person while also considering the network, power and processing constraints of the mobile device.