490 research outputs found

    A generic template for the evaluation of dialogue management systems

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    We present a generic template for spoken dialogue systems integrating speech recognition and synthesis with 'higher-level' natural language dialogue modelling components. The generic model is abstracted from a number of real application systems targetted at very different domains. Our research aim in developing this generic template is to investigate a new approach to the evaluation of Dialogue Management Systems. Rather than attempting to measure accuracy/speed of output, we propose principles for the evaluation of the underlying theoretical linguistic model of Dialogue Management in a given system, in terms of how well it fits our generic template for Dialogue Management Systems. This is a measure of 'genericness' or 'application-independence' of a given system, which can be used to moderate accuracy/speed scores in comparisons of very unlike DMSs serving different domains. This relates to (but is orthogonal to) Dialogue Management Systems evaluation in terms of naturalness and like measurable metrics (eg. Dybkjaer et al 1995, Vilnat 1996, EAGLES 1994, Fraser 1995); it follows more closely emerging qualitative evaluation techniques for NL grammatical parsing schemes (Leech et al 1996, Atwell 1996)

    EFFECTS OF RESERVOIR AQUATIC PLANT MANAGEMENT ON RECREATIONAL EXPENDITURES AND REGIONAL ECONOMIC ACTIVITY

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    Exotic aquatic plant management is a major concern for public reservoir management in many regions of the United States. A study was conducted to measure the effects of alternative aquatic plant management strategies on recreational expenditures and regional economic activity. The study areas was Lake Guntersville, Alabama, and the local economy surrounding the lake. Lake Guntersville is one of the largest reservoirs in the Tennessee Valley Authority system. Results suggested the relatively moderate levels of aquatic plant control are associated with the highest levels of recreation-related economic effects on the economy surrounding Lake Guntersville.Aquatic plants, Input-output analysis, Public reservoir management, Recreational expenditures, Regional economic activity, Resource /Energy Economics and Policy,

    What supports hospital pharmacist prescribing in Scotland? A mixed methods, exploratory sequential study.

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    While approximately half of all qualified hospital pharmacist independent prescribers (PIPs) in Scotland are active prescribers, there are major differences in prescribing activity across geographical areas. This study aimed to explore, through focus groups, interviews and a questionnaire, hospital PIPs' perceptions of factors associated with prescribing activity and to investigate the infrastructure required to better support active prescribing by PIPs. Findings reinforced the perceived positive impact of supportive pharmacy leadership within the organisation, recognition that prescribing is integral to the clinical pharmacist role and a work environment conducive to prescribing

    The variable toxicity of silver ions in cell culture media

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    The elevated interest in silver ions (Ag+) as a broad spectrum antimicrobial for use on medical devices has increased the number and importance of in vitro biocompatibility testing, however little consideration is given to the culture environment in which the assessments are performed. The current investigation assessed the viability of mouse fibroblasts (L929) exposed to different concentrations of Ag+ in both Dulbecco's modified Eagle's medium (DMEM) and minimal essential medium Eagle, alpha modification (αMEM). We identified a significant increase in the EC50 of L929 cells exposed to Ag+ in αMEM compared to DMEM, which was matched by a corresponding decrease in Ag+ availability in αMEM at concentrations ≤400 μM, as detected by inductively coupled plasma mass spectrometry (ICP-MS). The reduced availability was not observed for Ag+ > 400 μM, the concentration above which caused in vitro cytotoxicity in L929 cells in αMEM; while linear quantification of Ag+ was observed in DMEM. Equilibration of the chloride and glucose components between media did not affect cytotoxicity on primary test cells; mesenchymal stromal cells (MSCs). Overall, our results present evidence of the importance of culture conditions on the in vitro evaluation of silver, with DMEM providing a reliable basal media in which to conduct assessments

    Using a commercial speech recogniser within the domain of air traffic control

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    We have taken an off-the-shelf, commercial continuous speech recogniser and conducted tests using three syntaxes for the domain of Air Traffic Control. The syntaxes are based on a corpus of transmissions between the ATC and pilots and reflect three differing levels of "linguistic" knowledge. The first represented the system where, in effect, there would be no syntax but a lexicon of all words in the corpus. The second took a partial look at syntactic information by using a key phrase spotting mechanism. The third represented the entire syntax of the corpus. Initial experiments show that key phrase spotting is insignificantly more accurate than no syntax at all, whilst use of a complete syntax can improve performance, to a point. The benefits of a discourse grammar are briefly discussed

    Dialogue management systems: a survey and overview

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    This report provides an overview of the current issues and techniques for the modelling of dialogues using a computer. A dialogue management system can manage a dialogue between two or more agents, be they human or computer. Recently, increasingly complex dialogues are being modelled which allow a range of discourse phenomena including ellipsis and anaphoric reference. Such dialogues are thought to be similar to those between two humans, and accurate modelling of these phenomena leads to "pleasant", i.e. easy to talk to, and natural human-computer dialogues. Dialogue management can be classified into three often overlapping approaches: discourse grammars, plan-based and collaborative approaches. The design of a system often begins by eliciting the language used initially between two humans and later by Wizard of Oz experiments. Special issues relating to dialogue management systems are discussed including recovery strategies from different types of errors and the coding of dialogue in corpora. Lastly, approaches to evaluation are briefly discussed from the qualitative and quantitative viewpoints, recognising the importance and size of this sub-field

    Developing a corpus-based grammar model within a continuous commercial speech recognition package

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    This paper is derived from experiments with a commercial ’off-the-shelf’ continuous speech recognition system, applied to the apparently restricted domain of Air Traffic Control (ATC) for light aircraft. The system is required to transcribe key sub-phrases in a transmission by the ATC to a particular aircraft, the commercial speech recognition system providing the main recognition component. After the development of a corpus of transmissions, it was realised that key information is often interspersed with unconstrained English. Initial attempts focused on using a wildcard mechanism for the non-key sub- phrases. The mechanism, however, proved to be valuable only in simplistic grammars due to its overgenerative nature. The speech recognition system showed us that whilst useful mechanisms are provided, such as the wildcard mechanism, they tend to make over-simplistic assumptions about English grammar and dialogue structure

    Disruption of VGLUT1 in cholinergic medial habenula projections increases nicotine self-administration

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    Cholinergic projections from the medial habenula (MHb) to the interpeduncular nucleus (IPN) have been studied for their complex contributions to nicotine addiction and have been implicated in nicotine reinforcement, aversion, and withdrawal. While it has been established that MHb cholinergic projections co-release glutamate, no direct evidence has demonstrated a role for this glutamate projection in nicotine consumption. In the present study, a novel floxed Slc17a7 (VGLUT1) mouse was generated and used to create conditional knockout (cKO) mice that lack VGLUT1 in MHb cholinergic neurons. Loss of Slc17a7 expression in ventral MHb cholinergic neurons was validated using fluorescent in situ hybridization, and immunohistochemistry was used to demonstrate a corresponding reduction of VGLUT1 protein in cholinergic terminals in the IPN. We also used optogenetics-assisted electrophysiology to evoke excitatory post-synaptic currents in IPN and observed a reduction of glutamatergic currents in the cKO, supporting the functional disruption of VGLUT1 in MHb to IPN synapses. cKO mice exhibited no gross phenotypic abnormalities and displayed normal thigmotaxis and locomotor behavior in the open-field assay. When trained to lever press for food, there was no difference between control and cKO. However, when tested in a nicotine self-administration procedure we found that the loss of VGLUT1-mediated glutamate co-release led to increased responding for nicotine. These findings indicate that glutamate co-release from ventral MHb cholinergic neurons opposes nicotine self-administration, and provide additional support for targeting this synapse to develop potential treatments for nicotine addiction
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