Samit Bhattacharya

Performance Models for Automatic Evaluation of Virtual Scanning Keyboards

Virtual scanning keyboards are commonly used augmentative communication aids by persons with severe speech and motion impairments. Designers of virtual scanning keyboards face problems in evaluating alternate designs and hence in choosing the better design among alternatives. Automatic evaluation of designs will be helpful to designers in making the appropriate design choice. In this paper, we present performance models for virtual scanning keyboards that can be used for automatic evaluation. The proposed models address the limitations present in the reported work on similar models. We compared the model predictions with results from user trials and established the validity of the proposed models.

User Model to Design Adaptable Interfaces for Motor-Impaired Users

User modeling is an important strategy for designing effective user interface. User model for able-bodied user is not always suitable for physically and mentally retarded people. There are some special characteristics of users and also of the interfaces, which have to be considered when building a user model for disabled users. This paper concerns about modeling motor-impaired users for developing personalized interfaces for those people. In the proposed user model, main emphasis is given on making the user model application independent, clustering users according to their physical disability and cognitive level and adapting the model with respect to individual user as well as cluster of users.

A virtual predictive keyboard as a learning aid for people with neuro-motor disorders

In India, the population with severe neuro-motor impairments (like people suffering from cerebral palsy) faces an acute problem with electronic-learning because there is a dearth of quality learning aids available for them. By quality learning aids we mean certain softwares that can help this section of special users to learn fast and at the same time with ease. Though similar systems are available in the international market, all of such products have a cost ranging from a few hundred to a few thousand dollars. For an average Indian user, they are too costly to afford. Moreover these products come in foreign languages which cannot facilitate the learning of the Indian languages. Keeping these two problems in focus, we have tried to design and develop a few learning aids which helps these section of users to learn and that too in their own languages. All these tools are indigenous and at the same time available at an affordable price. In this paper we would discuss about a predictive virtual keyboard, which not only helps these users to learn typing but also helps them to write essays, letters, and even compose poetry. All of these they can do in their own language.

Computational Modeling of User Errors for the Design of Virtual Scanning Keyboards

Virtual scanning keyboards are used by persons with severe speech and motion impairments as communication aids. Each of these systems consists of a virtual keyboard and a ldquoscanning and access switchrdquo based alternate input method. Designers of such keyboards face problems due to the difficulties in testing prototypes with disabled users. Model-based design approaches were proposed in order to alleviate the problems. In model-based design, systems are evaluated with user models reducing the need for extensive user testing. The existing model-based approaches, however, do not consider the effect of user errors in evaluating systems. The lack of consideration of errors limits the practical usefulness of the resulting designs. To overcome this limitation, we have performed empirical studies of errors on virtual scanning keyboards. From our study results, we have derived predictive models of users error behavior. We have used the models to develop ldquoErrorProneness,rdquo a numerical error measure for virtual scanning keyboards. We have proposed a method using the ldquoErrorPronenessrdquo measure for taking the effects of errors into account in model-based design. Methods employed in our study, results obtained, the predictive user models, the error measure, and the proposed design method are presented in this paper.

Online Devanagari isolated character recognition for the iPhone using Hidden Markov Models

In this paper, we present a novel scheme, which is to be implemented on the iPhone, for the recognition of online handwritten basic isolated characters of the Devanagari script. Devanagari is an Indian script that is used for several major languages such as Hindi, Sanskrit, Marathi & Nepali and is spoken as well as written by more than 500 million people. Unconstrained Devanagari writing is more complex than English cursive due to the possible variations in the order number, direction and shape of constituent strokes. The Devanagari alphabet is split into 13 vowels & 36 consonants. A manual study of various characters was done and 42 stroke classes were created. A stroke based recognition approach has been designed where strokes are recognized using Hidden Markov Models (HMM). One HMM is constructed for each stroke class. A second stage of classification has been designed and is used for recognition of characters using stroke classification results along with look up tables. The distinguishing feature of our implementation of online handwriting recognition of isolated Devanagari characters is that it is being designed and implemented for the new iPhone platform and it takes care of various constraints this platform presents us with.

Virtual keyboard layout optimization

The use of virtual keyboards is becoming ubiquitous with increasing use in mobile devices and touch-screens. Till now the research has mainly focused on developing layouts which support high typing speed, but the error aspect has been largely ignored. This research aims at developing a novel error model which relates accuracy with a given layout using the distance between keys. The main idea here is that the error model should predict the error rate by the layout specification alone.

A behavioral approach to modeling Indian children's ability of adopting to e-learning environment

E-Learning is making inroads into schools in India in a large scale. Making use of information and communication technology (ICT) for learning can be very effective in delivering education to masses and thereby bridging the educational divide. How far is e-learning suitable, feasible and acceptable to school children of developing country like India is a question that needs careful study. This paper reports an exploratory study of investigating a school students perspective of acceptance of e-learning as a tool for supplementing school education. The Technology Acceptance Model (TAM) was used to model influence of factors like individual preferences, computer-friendliness, perceived ease-of-use, perceived usefulness, attitudes and intentions - on usage or adoption of e-learning by children. Childrens mental models were analysed for understanding their beliefs and feelings towards e-learning. The results show TAM to be partially effective tool in investigating childrens behavioural intention towards using e-learning. It was observed that facilitating conditions directly and strongly affected e-learning usage while intention to use e-learning was not much influential in driving the e-learning usage.

Sanyog: A Speech Enabled Communication System for the Speech Impaired and People with Multiple Disorders

SUMMARY The paper presents a multilingual communication tool that has been designed for helping in the communication needs of people with severe speech and multiple disorders. The system accepts icons, selected through special access switches, as input and can form natural language sentences, which can be spoken out using in-built text-to-speech synthesizer. The system has been deployed and is being field tested at the schools for the children with cerebral palsy in India.

Bengali text input interface design for mobile devices

Text entry has become one of the most frequent activities performed using mobile devices such as PDAs. Virtual keyboards (VK), which allow text to be entered by tapping keys displayed on the screen, are among the predominant mode of text input for such devices. It is important to design VK layouts in a way such that the users can achieve high text entry speed with high accuracy. Several layouts, primarily in English and also in some other languages, have been proposed to achieve the twin objectives. However, no such work has been reported for Bengali, the second and fifth most popular language of India and the world, respectively. The existing methods cannot be applied directly to Bengali VK design due to the problem of accommodating the large Bengali alphabet (more than 60 characters) on a small display area. In order to resolve the resulting usability-performance trade-off, this paper proposes a two-level design. Five two-level VKs representing three design paradigms (alphabetic, frequency-based and adaptive) have been designed and compared in an empirical study. The study results show that for mobile devices, the two-level adaptive design is expected to give best performance in terms of text entry rate and accuracy. The layouts as well as the procedure and results of the study are discussed in this paper.

Design of an Iconic Communication Aid for Individuals in India With Speech and Motion Impairments

Abstract India is home to a large number of individuals with significant speech and motion impairments. Many of these individuals are children and neo-literates who have little proficiency in their language of communication. In order to cater to such individuals in India, we have developed Sanyog, an icon-based communication aid. Sanyog accepts a sequence of icons as input and converts the input sequence to a grammatically correct sentence. Conversion of an iconic sequence to a sentence requires linguistic knowledge and resources that are not available for Bengali and Hindi, the two Indian languages for which Sanyog was developed. To overcome this problem, we have developed a novel user-computer interaction model. The interaction is facilitated by a suitably designed interface. The interaction model and the interface designed for Sanyog are presented in this article.