791 research outputs found
Automatic Transport Network Matching Using Deep Learning
Public transport users are increasingly expecting better service and up to date information, in pursuit of a seamless journey experience. In order to meet these expectations, many transport operators are already offering free mobile apps to help customers better plan their journeys and access real-time travel information. Leveraging the spatio-temporal data that such apps can produce at scale (i.e. timestamped GPS traces), opens an opportunity to bridge the gap between passenger expectations and capabilities of the operators by providing a real-time 360-degree view of the transport network based on the ‘Apps as infrastructure’ paradigm. The first step towards fulfilling this vision is to understand which routes and services the passengers are travelling on at any given time. Mapping a GPS trace onto a particular transport network is known as ‘network matching’. In this paper, the problem is formulated as a supervised sequence classification task, where sequences are made of geographic coordinates, time, and line and direction of travel as a label. We present and compare two data-driven approaches to this problem: (i) a heuristic algorithm, which looks for nearby stops and makes an estimation based on their timetables -- used as a baseline -- and (ii) a deep learning approach using a recurrent neural network (RNN). Since RNNs require considerable amounts of data to train a good model, and collecting and labelling this data from real users is a challenging task (e.g. asking too often can be overwhelming; privacy concerns on providing GPS location; not reliable labels due to mistakes or misuse), one of our contributions is a synthetic journey data generator. The datasets that we generated have been made as realistic as possible by querying real timetables and adding position and temporal noise to simulate variable GPS accuracy and vehicle delays, sampled from empirical distributions estimated using thousands of real location reports. To validate our approach we have used a separate dataset made of hundreds of real user journeys provided by a UK-based bus operator. Our experimental results are promising and our next step is to deploy a solution in a production environment. From the operator’s point of view, this will enable multiple smart applications like account based ticketing, identification of disruptions, real-time passenger counting, and network analysis. Passengers will also, therefore, benefit from a better service and an increase in the quality of information due to leveraging such big data processing
Technology Demonstration: Augmented Design Ideation
This technology demonstration showcases augmented design ideation tools that have been developed to explore hybrid design environments [1] using novel prototypes that use ambient informatics and ubiquitous computing approaches. The tool aims to enhance the creative scope of multi-participant design ideation by providing contextually relevant visual design prompts to enhance design ideation processes and conceptualisation [1]
Quantification of voriconazole in plasma by liquid chromatography-tandem mass spectrometry
A convenient liquid chromatography-tandem mass spectrometry method for the quantification of the triazole antifungal agent voriconazole in plasma samples is described. Fenbuconazole is used as an internal standard. After protein precipitation, automated solid-phase extraction is applied. Electrospray ionization in the positive mode is used and the following mass transitions are recorded: voriconazole, 350 -> 127; and fenbuconazol, 337 -> 125. The analytical run time is 4 min. The response was linear from 78 to 5000 mu g/L. The total coefficient of variation (n=16) was 12.6% for a low-concentration pool (143 mu g/L), 4.7% for a medium-concentration pool (419 mu g/L), and 5.0% for a high-concentration pool (4304 mu g/L). The method is proposed for future investigations that should be performed to test the hypothesis that therapeutic drug monitoring of voriconazole is clinically useful
Metabolism of the dihydropyridine calcium channel blockers mebudipine and dibudipine by isolated rat hepatocytes
The prototype 1,4-dihydropyridine (1,4-DHP) nifedipine, indicated for the management of hypertension and angina pectoris, has drawbacks of rapid onset of vasodilating action and a short half-life. Several newer analogues have been designed to offset these problems and these include mebudipine and dibudipine. These analogues contain t-butyl substituents that have been selected to alter the fast metabolism without altering pharmacological activity. In this study, the metabolism of mebudipine and dibudipine by isolated rat hepatocytes has been investigated. These compounds were extensively metabolized in 2 h by oxidative pathways, analogous to those known for nifedipine, and by O-glucuronidation after hydroxylation of the t-butyl substituents. The in-vitro half-lives of mebudipine (22 ± 7.1 min) and dibudipine (40 ± 9.8 min) were significantly longer than that of nifedipine (5.5 ± 1.1 min), which was investigated in parallel in this study. These newer 1,4-DHPs address the problem of the short half-life of nifedipine and have potential for further development in view of their comparable potency to nifedipine
Efficient Hadronic Operators in Lattice Gauge Theory
We study operators to create hadronic states made of light quarks in quenched
lattice gauge theory. We construct non-local gauge-invariant operators which
provide information about the spatial extent of the ground state and excited
states. The efficiency of the operators is shown by looking at the wave
function of the first excited state, which has a node as a function of the
spatial extent of the operator. This allows one to obtain an uncontaminated
ground state for hadrons.Comment: 18 pages, Latex text, followed by 11 postscript figures in
self-unpacking file. Also available at
ftp://suna.amtp.liv.ac.uk/pub/cmi/wavefn
Multiple pathways mediate the effects of climate change on maternal reproductive traits in a red deer population
Temporal changes in phenological traits arising as a consequence of recent rapid environmental change have been widely demonstrated in animal populations. Increasingly, studies are seeking to understand the impact of changes in such traits on individual fitness and population dynamics, with the ultimate aim of predicting population persistence or extinction under different climate scenarios. Here, we examined the effects of environmental change on maternal reproductive traits in a wild population of red deer (Cervus elaphus) and sought to explain why, despite a rapid advance in offspring birth dates, we observed no apparent consequences for offspring fitness. By using path analysis, we identified both direct and indirect paths along which changes in environmental conditions affected birth date, birth mass, juvenile survival, and female fecundity. In general, warmer temperatures were associated with earlier birth dates and greater birth mass, and higher rainfall was associated with reduced juvenile survival and reduced female fecundity. We also examined concurrent effects of population density, maternal age, and reproductive history, and found that temporal stasis in average trait values, at least in part, could be explained by antagonistic roles of direct and indirect effects of changing climate and increasing population density. Identification of the many mechanisms that contribute to the dynamics of phenotypic traits is challenging; this study demonstrates the need to consider both climatic and demographic variation in order to understand the fitness consequences of changes in phenological traits. Read More: http://www.esajournals.org/doi/abs/10.1890/13-0967.
Cars, Congestion, Public Transport, and Pricing: A Reality Check
For some little while now, the flavour of the month in transport policy seems to have been to set goals for massive relative increases in public transport ridership, reduction of car use, all resulting in a hoped-for reduction in road congestion. As a result of this policy focus, we have seen various government entities at the metropolitan, state, and national levels set goals for such activities as increased ride sharing, increased use of public transport, implementation of high occupancy vehicle lanes, and, at least in Australia and the U.K., thinking about congestion pricing of some form. Through political rhetoric, it seems that use of the private car, congestion, and declining shares of the market for public transport are all labeled as negatives that should be set right by some type of policy intervention. Since the first introduction of ideas of demand management in the late 1970s, the idea of trying to change behaviour of car users has been an increasingly significant focus of transport policy. This paper seeks to check the reality of these policy directions and questions whether these are desirable, let alone achievable end states. It is noted that major changes in transport market share have never been achieved in the past, and as such, it seems unlikely that such policies will be successful in the long term. Even if such policies can be achieved, it is questionable whether the end results will have desirable consequences or not
Future Urban Passenger Transportation Systems Alternatives: Life Styles and Values
Institute of Transport and Logistics Studies. Business School. The University of Sydney
Future Urban Passenger Transportation Systems Alternatives: Life Styles and Values
Institute of Transport and Logistics Studies. Business School. The University of Sydney
Deploying traditional and smartphone app survey methods in measuring door-to-door travel satisfaction in eight European cities
This study describes the lessons learned from designing, deploying and analysing the results from different travel satisfaction survey tools which measures the travellers' door-to-door travel satisfaction. The travel satisfaction measurement survey tools tested consisted of two types of smartphone applications (a satellite navigation app and a game app), an on-line survey, a paper-based semi-structured questionnaire and a focus group questionnaire. Each of the measurement tools comprised the same set of basic questions, but in different formats, aimed at exploring the pros and cons of each tool among different groups of travellers. The data collection was carried out at eight different European cities and five FIA motorist networks. 5,275 valid responses were gathered from the survey. Further analysis results show that different survey methods performed better in different sites. The satisfaction that was gathered via main trip leg does not necessarily correspond with overall satisfaction of the door-to-door journey. The results of this study highlight the need for more inclusive, complete, door-to-door, travel survey measurements
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