Stavroula-Evita Fotinea

Educational resources and implementation of a Greek sign language synthesis architecture

In this paper, we present how creation and dynamic synthesis of linguistic resources of Greek Sign Language (GSL) may serve to support development and provide content to an educational multitask platform for the teaching of GSL in early elementary school classes. The presented system utilizes standard virtual character (VC) animation technologies for the synthesis of sign sequences/streams, exploiting digital linguistic resources of both lexicon and grammar of GSL. Input to the system is written Greek text, which is transformed into GSL and animated on screen. To achieve this, a syntactic parser decodes the structural patterns of written Greek and matches them into equivalent patterns of GSL, which are then signed by a VC. The adopted notation system for the representation of GSL phonology incorporated in the systems lexical knowledge database, is Hamburg Notation System (HamNoSys). For the implementation of the virtual signer tool, the definition of the VC follows the h-anim standard and is implemented in a web browser using a standard VRML plug-in.

A knowledge-based sign synthesis architecture

This paper presents the modules that comprise a knowledge-based sign synthesis architecture for Greek sign language (GSL). Such systems combine natural language (NL) knowledge, machine translation (MT) techniques and avatar technology in order to allow for dynamic generation of sign utterances. The NL knowledge of the system consists of a sign lexicon and a set of GSL structure rules, and is exploited in the context of typical natural language processing (NLP) procedures, which involve syntactic parsing of linguistic input as well as structure and lexicon mapping according to standard MT practices. The coding on linguistic strings which are relevant to GSL provide instructions for the motion of a virtual signer that performs the corresponding signing sequences. Dynamic synthesis of GSL linguistic units is achieved by mapping written Greek structures to GSL, based on a computational grammar of GSL and a lexicon that contains lemmas coded as features of GSL phonology. This approach allows for robust conversion of written Greek to GSL, which is an essential prerequisite for access to e-content by the community of native GSL signers. The developed system is sublanguage oriented and performs satisfactorily as regards its linguistic coverage, allowing for easy extensibility to other language domains. However, its overall performance is subject to current well known MT limitations.

GSLC: creation and annotation of a Greek sign language corpus for HCI

In the framework of a research target that aims at integration of sign language technologies to human-computer interaction applications, creation and annotation of the Greek Sign Language Corpus (GSLC) involve, on the one hand, data and analysis of the phonological structure of morphemes of Greek Sign Language (GSL) and, on the other hand, collection of sentence level language samples and assignment of their respective annotations. GSLC also entails free sign narrations fully annotated at least for sentence segmentation. Simple and complex sign morpheme formation is directly relevant to development of sign recognition prototypes. In this sense, a sign language corpus intended to support sign recognition by exploitation of a language model has to entail sufficient data from simple- to complex- morpheme level. Sentence level annotation, except for sentence boundaries, focuses on phrase boundary marking and grammar information often conveyed by multi-layer markers, as is the case of e.g. topicalisation, nominal phrase formation, temporal indicators, question formation and sentential negation in GSL.

Sign Language Recognition, Generation, and Modelling: A Research Effort with Applications in Deaf Communication

Sign language and Web 2.0 applications are currently incompatible, because of the lack of anonymisation and easy editing of online sign language contributions. This paper describes Dicta-Sign, a project aimed at developing the technologies required for making sign language-based Web contributions possible, by providing an integrated framework for sign language recognition, animation, and language modelling. It targets four different European sign languages: Greek, British, German, and French. Expected outcomes are three showcase applications for a search-by-example sign language dictionary, a sign language-to-sign language translator, and a sign language-based Wiki.

Developing an e-Learning Platform for the Greek Sign Language

In this paper we introduce the characteristics of the educational platform that is being developed within the SYNENNOESE project. The platform integrates avatar and animation technologies, exploiting electronic linguistic resources of the Greek Sign Language (GSL), in order to provide a Greek-to-GSL conversion tool that allows to construct, store and maintain educational material in GSL. Besides reference to tool development in the context of a specific application, emphasis is placed on the adaptability of the Greek-to-GSL converter as a tool in line with the requirement for Universal Access and the Design for All principles in the context of Information Society.

Gesture and Sign Language in Human-Computer Interaction and Embodied Communication

This book constitutes revised selected papers from the 9th International Gesture Workshop, GW 2011, held in Athens, Greece, in May 2011. The 24 papers presented were carefully reviewed and selected from 35 submissions. They are ordered in five sections named: human computer interaction; cognitive processes; notation systems and animation; gestures and signs: linguistic analysis and tools; and gestures and speech.

The dicta-sign wiki: enabling web communication for the deaf

The paper provides a report on the user-centred showcase prototypes of the DICTA-SIGN project (http://www.dictasign.eu/), an FP7-ICT project which ended in January 2012. DICTA-SIGN researched ways to enable communication between Deaf individuals through the development of human-computer interfaces (HCI) for Deaf users, by means of Sign Language. Emphasis is placed on the Sign-Wiki prototype that demonstrates the potential of sign languages to participate in contemporary Web 2.0 applications where user contributions are editable by an entire community and sign language users can benefit from collaborative editing facilities.

A prototype Greek text to Greek Sign Language conversion system

In this article, a prototype Greek text to Greek Sign Language (GSL) conversion system is presented. The system is integrated into an educational platform that addresses the needs of teaching GSL grammar and was developed within the SYNENNOESE project (Efthimiou et al. 2004a. Developing an e-learning platform for the Greek sign language. In: K. Miesenberger, J. Klaus, and W. Zagler, eds. Computer helping people with special needs, Lecture Notes in Computer Science, Springer-Verlag, vol. 3118, 1107–1113). The detailed implementation of the language-processing component of a Greek text to GSL conversion system is provided, focusing upon the inherent problems of knowledge elicitation of sign language (SL) grammar and its implementation within a parser framework. It is based on an SL dictionary (Efthimiou et al. 2004a) database of coded GSL knowledge. The proposed system has been designed and implemented after considering most state-of-the-art SL machine translation or Conversion systems, such as Vsigns (Papadogiorgaki et al. 2004. VSigns – a virtual sign synthesis web tool. In: Proceedings of Sixth COST 276 Workshop on Information and Knowledge Management for Integrated Media Communication, May 2004, Thessaloniki, Greece), ZARDOZ (Veale et al. 1998. The challenges of cross-modal translation: English to sign language translation in the ZARDOZ system. Machine Translation, 13, 81–106) and SignSynth (Angus 2001. SignSynth: a sign language synthesis application using Web3D and Perl. In: Gesture and Sign Lanauage in Human–Computer Interaction. London, UK: International Gesture Workshop), and taking into account their advantages and disadvantages. The overall architecture is innovative since other existing systems either do not consider the GSL or they cannot be effectively applied on sentences but just on single words. The system is demonstrable on any conventional PC.

Signal enhancement for continuous speech recognition

This paper presents a comparison between two parametric methods for Signal Enhancement in order to address the problem of robust Automatic Speech Recognition (ASR). An SVD-based technique (ISE) and a non-linear spectral subtraction method (NSS), have been evaluated by means of the Continuous Speech Recognition system that is used in the ERMIS project. The input signal is corrupted with coloured noise with variable signal-to-noise ratio. It was found that fine-tuning of the various parameters of the enhancement techniques is crucial for efficient optimisation of their performance. Both methods provide significant improvement of the speech recogniser performance in the presence of coloured noise, with the NSS method being slightly better.

From grammar-based MT to post-processed SL representations

Abstract This paper proposes the implementation of a post-processing stage to a grammar-based machine translation (MT) system from written into sign language for the pair written Greek–Greek sign language (GSL), where translation output is visualized by an avatar. Post-processing is applied on the output of the MT system’s transfer module by activating an editing environment for SL which utilizes a dictionary of signs coded for HamNoSys transcriptions and non-manual elements along with grammar knowledge. This post-processing environment may also be used as a standalone editing environment for expert users allowing for a considerable range of editing actions, as well as an SL editing tool for the general public who are not familiar with the underlying technology. In both cases, this environment provides the opportunity of on-the-fly structuring of new signed utterances going far beyond current limitations in composition with new signed language content.