Partial Matrix Techniques.

Partial matrix techniques are those in which gravity models are fitted to a partially observed matrix of trips and journey costs, and used to infer the trips in the unobserved cells. This paper reviews the theoretical basis from which such techniques have been developed, and demonstrates the need to pay careful attention to the - underlying assumptions, which in effect require that the model be a good fit to be observed data (and also a good 'fit' to the unobserved data). Circumstances are described in which the estimates for the unobserved cells may not be uniquely determined, and the effects of data structure on the reliability of the estimates (assuming these to be unique) are discussed. Ways are suggested in which further theoretical and empirical research might demonstrate whether a given pattern of observations would lead to particularly error-prone estimates

How Can Speech Recognisers Help Applied Research in the Civil Engineering, Transport and Related Industries

BACKGROUND Speech recognition technology is rapidly advancing to the point here it can be usefully applied in a wide range of mtexts. For applications within the SERC Environment Committee's area of interest -civil engineering; construction; building; transport; water resources there are a number of kinds of recording situation in which one needs to keep one's eyes on the situation being studied; or in which the recording conditions (eg moving around with instruments) are unfavourable. The limitations of conventional pen and paper recording for these situations are obvious; and the limitations of hand-held data capture devices are also becoming apparent. Speech is therefore an easier medium to use; and a tape recorder a convenient means of recording the observations. For well defined recording tasks; speech recognisers might be a helpful way of transcribing the record. This seminar was convened to enable those who are potentially interested in such an application of information technology to hear of the latest developnents and assessments of the suitability of the technology

Report on the Workshop held at the University of Leeds on 6 November organised on behalf of the Transport Sub-Committee of the Environment Committee of the Science and Engineering Research Council

The meeting was the second in a series of three; called to review the prospects for future development of the Special Programme in the Application of Information Technology to Transport set up by the Transport Sub-committee of the Science and Engineering Research Council (SERC). The other seminars were: at University College London on Traffic Engineering Applications; held in July 1986; and at the University of Newcastle up Tyne, on Public Transport Information Systems, held in December 1986. The objectives of the workshop were to (i) review current perceptions of and future prospects for the role of expert systems in transport; and (ii) provide such feed-back to the SERC Transport Sub-committee as would assist it in forming a view about future work in this area. (Continues..

Microsimulation of Organised Car Sharing – Model Predications and Policy Implications.

This paper presents the results of a range of tests of organised car sharing schemes. The performance of the schemes is predicted using a sophisticated microsimulation model. A brief resume of the model is followed by a description of the tests and an analysis of their results. Conclusions are drawn on the place of organised car sharing within broader transport policies, the performance of the model when compared to the available empirical data and directions for public research. The tests here presented include: a series of sensitivity analyses; tests of organisational strategies for car sharing schemes; tests of schemes in a variety of locations and at a variety of scales and finally a batch of tests which investigate the effect of major changes in the operating environment of car sharing schemes - changes in the price of fuel and public transport fares and the provision of parking space incentives for car sharers for example

Applications of Expert Systems in Transport

BACKGROUND Experienced judgement and specialist knowledge are essential to the proper specification, understanding and interpretation of data and computer analyses. The human expert has traditionally supplied this knowledge and judgement with the computer doing the necessary number-crunching. However, artificial intelligence (AI) research provides ways of embodying this knowledge and judgement within computer programs. Despite an early lead in the field, UK research and developmnent into AI techniques was held back in the 1970s when the then Science Research Council took the view that the 'combinatorial explosion' of possibilities would be an insurmountable obstacle to AI developent. But in America and Japan research continued, and the surge of interest in the 1980s has been a consequence of the 'Fifth Generation Computer' research programme initiated by Japan (Feigenbaum and McCorduck; 1984). This led in Europe to the ESPRIT programme of advanced technology research, and in the UK to the Alvey programme (Department of Industry, 1982). As a result, all sectors of industry have been encouraged to consider how such advanced technology can be applied, and the transport industry is no exception. This paper sets out to explain some of the relevant techniques in simple terms, and to describe a number of situations in which transport planning and operations might be helped through their use, illustrating this by reference to the pioneering work going on in transport applications in the USA, Britain and Australia

The Internal Validation of a National Model of Long Distance Traffic.

During 1980/81, the Department of Transport developed a model for describing the distribution of private vehicle trips between 642 districts in Great Britain, using data from household and roadside interviews conducted in 1976 for the Regional Highways Traffic Model, and a new formulation of the gravity model, called a composite approach, in which shorter length movements were described at a finer level of zonal detail than longer movements. This report describes the results of an independent validation exercise conducted for the Department, in which the theoretical basis of the model and its the quality of its fit to base year data were examined. The report discusses model specification; input data; calibration issues; and accuracy assessment. The main problems addressed included the treatment of intrazonal and terminal costs, which was thought to be deficient; the trip-end estimates to which the model was constrained, which were shown to have substantial variability and to be biassed (though the cause of the latter could be readily removed), with some evidence of geographical under-specification; and the differences between roadside and household interview estimates. The report includes a detailed examination of the composite model specification and contains suggestions for improving the way in which such models are fitted. The main technical developments, for both theory and practice, are the methods developed for assessing the accuracy of the fitted model and for examining the quality of its fit with respect to the observed data, taking account of the variances and covariances of modelled and data values. Overall, the broad conclusion was that, whilst there appeared to be broad compatibility between modelled and onserved data in observed cells, there was clear evidence of inadequacy in certain respects, such as for example underestimation of intradistr ict trips. This work was done in co-operation with Howard Humphreys and Partners and Transportation Planning Associates, who validated the model against independent external data; their work is reported separately

Urban Roads Appraisal.

This note is our response to SACTRA's invitation to submit suggestions for desirable and practicable improvements in methods for assessing options for the strategic improvement of urban roads. We understand that SACTRA's emphasis is on the economic and environmental appraisal of a range of options from traffic management to major road construction. Our note reflects this. It draws on our experience in research into a wide range of urban transport problems and solutions (Kirby, 1984), our recent review of procedures for policy formulation and appraisal in the provincial conurbations (May et al, 1984), our close working relationship with West Yorkshire MCC, and the local government experience of some of our members, particularly with the GLC. This note serves to highlight some of our concerns about the appraisal process. Part one considers in turn: Necessary extension of the appraisal process. The style of the appraisal process. The need for consistency between the forecasting and evaluation procedures. The need for improvement in the analysis/forecasting techniques used in appraisal. The scope for technical discretion and its influence on results. Part two gives more detail on some of the topics discussed in part one - references to it are embedded in the text of part one - but does not detail our specific proposals for dealing with the issues raised. Further information on our ideas on these topics could be provided on request. A central concern, which lies behind many of our comments, is that the currently recommended procedures for appraising inter- urban road schemes would be quite inappropriate to urban road schemes. They are, we believe, surpassed by procedures currently in use in some of the larger local authorities let alone by the latest technical developments and research findings which have yet to become standard practice

Voice Degradation in Using Speech Recognisers for Transcribing Inventory Data: Draft Final Report

It is known that problems arise in long sessions of voice tape-recording for off-line data entry to computers via speech recognition systems, as a result of operator fatigue or loss of attention. In this study the task of reading vehicle licence plates aloud for one hour was simulated in laboratory conditions, each speaker undergoing one recording session with feedback on recognition accuracy and one without feedback. No significant difference in recognition success rates between the two conditions was discovered. The audio tape-recordings of the sessions were analysed acoustically for fatigue-induced changes both in long-term prosodic characteristics (including fundamental frequency, intensity, spectral balance and rate) and in segmental characteristics such as frequency of occurrence of different sound types and segmental durations. Although a number of intra-speaker di-fferences were detected in various measures, no consistent tendencies were found in all speakers. It is concluded that the choice of speakers and conditions resulted in insufficient fatigue to produce clear-cut effects; however, it is felt that the more sophisticated techniques developed during the project on the basis of the automatic segmentation of continuous speech is capable of more revealing analysis than the relatively crude techniques used previously. It is not felt likely that this would result in automatic techniques for improving speech recognition accuracy, but it could form the basis for more effective operator training and assessment of new applications and techniques

Applied Evaluation of Speech Recognisers with Respect to Tape Recorded Data.

In several transport planning and maintenance survey applications data can be efficiently captured by audio tape-recording. Such recording is useful in situations where the rapidity of events; or the need for the operator to keep his eyes on the objects being recorded; make it difficult to use other recording methods such as paper and pencil; or keyboards. Examples of the sort of situations considered in this report are car registration plate surveys (moving and parked vehicles) ; and street furniture inventory surveys. The transcription of such tape recorded data has; up until now; been a time consuming and labour intensive process; and it was therefore decided to investigate the possibility of using a speech recogniser to automatically transcribe the data. Whilst laboratory studies of the efficacy of the speech recognition process have of course been carried out; there have been very few field trials to evaluate the technology in specific application areas. This paper describes such an evaluation; for the case in which the speech recogniser is used for transcribing data recorded on an audio cassette. Different types of recogniser were tested on data recorded under both laboratory and field conditions. The suitability of associated equipment; (microphones and tape recorders); is also assessed for use with speech recognisers; and the recommended models are described. A training programme is suggested for new users and the results of the equipment trials and training program are presented. Camparisons are also made with other more traditional methods of data collection and transcription

The Automatic Transcription of Tape-Recorded Data.

There are a number of situations where, because of the rapidity of events, it is easier to record data by speaking it onto an audio cassette rather than recording it by other means, e.g. paper and pencil recording. The problem with spoken data is that considerable effort is then required to transcribe the data onto a computer for subsequent analysis. This paper describes the use of automatic speech recognisers for transcribing such data recorded under both laboratory and field conditions. Different types of recognisers are compared along with associated equipment (microphones and tape recorders). A training prcgramne is suggested for new users and the results of the equipment trials and training programne are presented. Comparisons are also made with other more traditional methods of data collection and transcription