Survey of the State of the Art in Natural Language Generation: Core tasks, applications and evaluation

This paper surveys the current state of the art in Natural Language Generation (NLG), defined as the task of generating text or speech from non-linguistic input. A survey of NLG is timely in view of the changes that the field has undergone over the past decade or so, especially in relation to new (usually data-driven) methods, as well as new applications of NLG technology. This survey therefore aims to (a) give an up-to-date synthesis of research on the core tasks in NLG and the architectures adopted in which such tasks are organised; (b) highlight a number of relatively recent research topics that have arisen partly as a result of growing synergies between NLG and other areas of artificial intelligence; (c) draw attention to the challenges in NLG evaluation, relating them to similar challenges faced in other areas of Natural Language Processing, with an emphasis on different evaluation methods and the relationships between them.Comment: Published in Journal of AI Research (JAIR), volume 61, pp 75-170. 118 pages, 8 figures, 1 tabl

The design of speech-based automated mobile phone services using interface metaphors

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Interface metaphor is a widely used design technique for interactive computer systems. The advantages of using interface metaphors derive from their ability to promote active learning, which enables a user to transfer knowledge from a familiar real world domain, to an unfamiliar computing domain. Interface metaphor is not currently used for the design of automated phone services, and it was the aim of this thesis to examine whether interface metaphor could improve the usability of speech-activated automated mobile phone services. A human-centred design methodology was followed to generate, select, and develop potential metaphors, which were used to implement metaphor-based phone services. An experimental methodology was then used to compare the usability of the metaphor-based services with the usability of currently available number-based phone services. The first experiment examined the effect of three different interface metaphors on the usability of a mobile city guide service. Usability was measured as a range of performance and attitude measures, and was supplemented by telephone interview data. After three consecutive days of usage, participants both preferred, and performed better with, the service that was based on an office filing system metaphor. Experiment two was conducted over a six week period, and investigated the effect of users' individual differences, and the context of use, on the usability of both the office filing system metaphor-based service, and a non-metaphor service. The results showed that performance with the metaphor-based service was significantly better than performance with the non-metaphor service. The usability of the metaphor-based service was not significantly affected by users' individual characteristics and aptitudes, whereas the number-based service was, suggesting that metaphor-based services may be more usable for a wider range of potential users. Usability levels for both services were found to be consistent across both private and public locations of use, suggesting that speech-activated mobile phone services provide a flexible means of information access. Experiment three investigated the strategies used by participants when interacting with mobile phone services, specifically the visualisation strategy that was used by two thirds of the metaphor-based service participants in experiment two. In addition to the attitude and performance measures used for experiments one and two, face-to face interviews were conducted with participants. The results indicated that significantly more participants visualised the metaphor-based services relative to a non-metaphor service, and that visualisation of the service structure led to significant performance improvements. This thesis has demonstrated the usability benefits of interface metaphor as a design technique for speech-based mobile phone services. These benefits of metaphor appear to derive from their ability to provide a mental model of the phone service that can be visualised, and their ability to accommodate the individual differences of users

Directional adposition use in English, Swedish and Finnish

Directional adpositions such as to the left of describe where a Figure is in relation to a Ground. English and Swedish directional adpositions refer to the location of a Figure in relation to a Ground, whether both are static or in motion. In contrast, the Finnish directional adpositions edellä (in front of) and jäljessä (behind) solely describe the location of a moving Figure in relation to a moving Ground (Nikanne, 2003). When using directional adpositions, a frame of reference must be assumed for interpreting the meaning of directional adpositions. For example, the meaning of to the left of in English can be based on a relative (speaker or listener based) reference frame or an intrinsic (object based) reference frame (Levinson, 1996). When a Figure and a Ground are both in motion, it is possible for a Figure to be described as being behind or in front of the Ground, even if neither have intrinsic features. As shown by Walker (in preparation), there are good reasons to assume that in the latter case a motion based reference frame is involved. This means that if Finnish speakers would use edellä (in front of) and jäljessä (behind) more frequently in situations where both the Figure and Ground are in motion, a difference in reference frame use between Finnish on one hand and English and Swedish on the other could be expected. We asked native English, Swedish and Finnish speakers’ to select adpositions from a language specific list to describe the location of a Figure relative to a Ground when both were shown to be moving on a computer screen. We were interested in any differences between Finnish, English and Swedish speakers. All languages showed a predominant use of directional spatial adpositions referring to the lexical concepts TO THE LEFT OF, TO THE RIGHT OF, ABOVE and BELOW. There were no differences between the languages in directional adpositions use or reference frame use, including reference frame use based on motion. We conclude that despite differences in the grammars of the languages involved, and potential differences in reference frame system use, the three languages investigated encode Figure location in relation to Ground location in a similar way when both are in motion. Levinson, S. C. (1996). Frames of reference and Molyneux’s question: Crosslingiuistic evidence. In P. Bloom, M.A. Peterson, L. Nadel & M.F. Garrett (Eds.) Language and Space (pp.109-170). Massachusetts: MIT Press. Nikanne, U. (2003). How Finnish postpositions see the axis system. In E. van der Zee & J. Slack (Eds.), Representing direction in language and space. Oxford, UK: Oxford University Press. Walker, C. (in preparation). Motion encoding in language, the use of spatial locatives in a motion context. Unpublished doctoral dissertation, University of Lincoln, Lincoln. United Kingdo

Computational Understanding, Generation and Evaluation of Creative Expressions

Computational creativity has received a good amount of research interest in generating creative artefacts programmatically. At the same time, research has been conducted in computational aesthetics, which essentially tries to analyse creativity exhibited in art. This thesis aims to unite these two distinct lines of research in the context of natural language generation by building, from models for interpretation and generation, a cohesive whole that can assess its own generations. I present a novel method for interpreting one of the most difficult rhetoric devices in the figurative use of language: metaphors. The method does not rely on hand-annotated data and it is purely data-driven. It obtains the state of the art results and is comparable to the interpretations given by humans. We show how a metaphor interpretation model can be used in generating metaphors and metaphorical expressions. Furthermore, as a creative natural language generation task, we demonstrate assigning creative names to colours using an algorithmic approach that leverages a knowledge base of stereotypical associations for colours. Colour names produced by the approach were favoured by human judges to names given by humans 70% of the time. A genetic algorithm-based method is elaborated for slogan generation. The use of a genetic algorithm makes it possible to model the generation of text while optimising multiple fitness functions, as part of the evolutionary process, to assess the aesthetic quality of the output. Our evaluation indicates that having multiple balanced aesthetics outperforms a single maximised aesthetic. From an interplay of neural networks and the traditional AI approach of genetic algorithms, we present a symbiotic framework. This is called the master-apprentice framework. This makes it possible for the system to produce more diverse output as the neural network can learn from both the genetic algorithm and real people. The master-apprentice framework emphasises a strong theoretical foundation for the creative problem one seeks to solve. From this theoretical foundation, a reasoned evaluation method can be derived. This thesis presents two different evaluation practices based on two different theories on computational creativity. This research is conducted in two distinct practical tasks: pun generation in English and poetry generation in Finnish.Laskennallista luovuutta on tutkittu paljon puhtaan tuottamisen näkökulmasta ja saman aikaan tutkimusta on tehty laskennallisen estetiikan saralla. Väitöskirjani yhdistää näitä kahta eri koulukuntaa, sillä kehittämäni laskennallisesti luovat järjestelmät käyttävät tuottamisessa apuna estetiikkaa; järjestelmät siis tulkitsevat teoksiaan samaan aikaan, kun ne niitä tuottavat. Käsittelen väitöskirjassani metaforien automaattista tulkintaa, värien nimien tuottamista, sloganien tuottamista sekä suomenkielisen runouden tuottamista. Metodeina käytän perinteistä koneoppimisalgoritmia, eli niin kutsuttua geneettistä algoritmia, sekä neuroverkkoja. Niiden yhdistelmää nimitän mestari ja oppipoika -malliksi, jossa geneettinen algoritmi opettaa neuroverkkoja

How Censorship in China Allows Government Criticism but Silences Collective Expression

We offer the first large scale, multiple source analysis of the outcome of what may be the most extensive effort to selectively censor human expression ever implemented. To do this, we have devised a system to locate, download, and analyze the content of millions of social media posts originating from nearly 1,400 different social media services all over China before the Chinese government is able to find, evaluate, and censor (i.e., remove from the Internet) the large subset they deem objectionable. Using modern computer-assisted text analytic methods that we adapt to and validate in the Chinese language, we compare the substantive content of posts censored to those not censored over time in each of 85 topic areas. Contrary to previous understandings, posts with negative, even vitriolic, criticism of the state, its leaders, and its policies are not more likely to be censored. Instead, we show that the censorship program is aimed at curtailing collective action by silencing comments that represent, reinforce, or spur social mobilization, regardless of content. Censorship is oriented toward attempting to forestall collective activities that are occurring now or may occur in the future --- and, as such, seem to clearly expose government intent.Governmen

Conducting Online Focus Groups - Practical Advice for Information Systems Researchers

Video-based online focus groups (OFGs) present an emerging opportunity for Information Systems (IS) researchers to circumvent spatial and temporal constraints in collecting rich data. They enable researchers to overcome interpersonal and operational challenges arising from face-to-face (F2F) focus groups (FGs) by allowing participants, who are located anywhere in the world, to share their personal experiences from behind their screens. However, the realization of the full potential of OFGs for IS research is currently hampered by challenges and uncertainty over best practices when conducting such FGs. Consequently, we offer a detailed account of our own experiences with seven OFGs in the context of digital platforms. In supplementing our own experiences with those of others reported in extant literature on (online) FGs in and beyond the IS discipline, we (a) arrive at hurdles inherent to the OFG method, (b) derive lessons learned from our own experience with OFGs, and (c) prescribe actionable advice to researchers who are interested in conducting OFGs in the future

What matters to older people with assisted living needs? A phenomenological analysis of the use and non-use of telehealth and telecare

Telehealth and telecare research has been dominated by efficacy trials. The field lacks a sophisticated theorisation of [a] what matters to older people with assisted living needs; [b] how illness affects people's capacity to use technologies; and [c] the materiality of assistive technologies. We sought to develop a phenomenologically and socio-materially informed theoretical model of assistive technology use. Forty people aged 60–98 (recruited via NHS, social care and third sector) were visited at home several times in 2011–13. Using ethnographic methods, we built a detailed picture of participants' lives, illness experiences and use (or non-use) of technologies. Data were analysed phenomenologically, drawing on the work of Heidegger, and contextualised using a structuration approach with reference to Bourdieu's notions of habitus and field. We found that participants' needs were diverse and unique. Each had multiple, mutually reinforcing impairments (e.g. tremor and visual loss and stiff hands) that were steadily worsening, culturally framed and bound up with the prospect of decline and death. They managed these conditions subjectively and experientially, appropriating or adapting technologies so as to enhance their capacity to sense and act on their world. Installed assistive technologies met few participants' needs; some devices had been abandoned and a few deliberately disabled. Successful technology arrangements were often characterised by ‘bricolage’ (pragmatic customisation, combining new with legacy devices) by the participant or someone who knew and cared about them. With few exceptions, the current generation of so-called ‘assisted living technologies’ does not assist people to live with illness. To overcome this irony, technology providers need to move beyond the goal of representing technology users informationally (e.g. as biometric data) to providing flexible components from which individuals and their carers can ‘think with things’ to improve the situated, lived experience of multi-morbidity. A radical revision of assistive technology design policy may be needed