10 research outputs found
QDEE: Question Difficulty and Expertise Estimation in Community Question Answering Sites
In this paper, we present a framework for Question Difficulty and Expertise
Estimation (QDEE) in Community Question Answering sites (CQAs) such as Yahoo!
Answers and Stack Overflow, which tackles a fundamental challenge in
crowdsourcing: how to appropriately route and assign questions to users with
the suitable expertise. This problem domain has been the subject of much
research and includes both language-agnostic as well as language conscious
solutions. We bring to bear a key language-agnostic insight: that users gain
expertise and therefore tend to ask as well as answer more difficult questions
over time. We use this insight within the popular competition (directed) graph
model to estimate question difficulty and user expertise by identifying key
hierarchical structure within said model. An important and novel contribution
here is the application of "social agony" to this problem domain. Difficulty
levels of newly posted questions (the cold-start problem) are estimated by
using our QDEE framework and additional textual features. We also propose a
model to route newly posted questions to appropriate users based on the
difficulty level of the question and the expertise of the user. Extensive
experiments on real world CQAs such as Yahoo! Answers and Stack Overflow data
demonstrate the improved efficacy of our approach over contemporary
state-of-the-art models. The QDEE framework also allows us to characterize user
expertise in novel ways by identifying interesting patterns and roles played by
different users in such CQAs.Comment: Accepted in the Proceedings of the 12th International AAAI Conference
on Web and Social Media (ICWSM 2018). June 2018. Stanford, CA, US
Characterizing Driving Context from Driver Behavior
Because of the increasing availability of spatiotemporal data, a variety of
data-analytic applications have become possible. Characterizing driving
context, where context may be thought of as a combination of location and time,
is a new challenging application. An example of such a characterization is
finding the correlation between driving behavior and traffic conditions. This
contextual information enables analysts to validate observation-based
hypotheses about the driving of an individual. In this paper, we present
DriveContext, a novel framework to find the characteristics of a context, by
extracting significant driving patterns (e.g., a slow-down), and then
identifying the set of potential causes behind patterns (e.g., traffic
congestion). Our experimental results confirm the feasibility of the framework
in identifying meaningful driving patterns, with improvements in comparison
with the state-of-the-art. We also demonstrate how the framework derives
interesting characteristics for different contexts, through real-world
examples.Comment: Accepted to be published at The 25th ACM SIGSPATIAL International
Conference on Advances in Geographic Information Systems (ACM SIGSPATIAL
2017
Accident Risk Prediction based on Heterogeneous Sparse Data: New Dataset and Insights
Reducing traffic accidents is an important public safety challenge,
therefore, accident analysis and prediction has been a topic of much research
over the past few decades. Using small-scale datasets with limited coverage,
being dependent on extensive set of data, and being not applicable for
real-time purposes are the important shortcomings of the existing studies. To
address these challenges, we propose a new solution for real-time traffic
accident prediction using easy-to-obtain, but sparse data. Our solution relies
on a deep-neural-network model (which we have named DAP, for Deep Accident
Prediction); which utilizes a variety of data attributes such as traffic
events, weather data, points-of-interest, and time. DAP incorporates multiple
components including a recurrent (for time-sensitive data), a fully connected
(for time-insensitive data), and a trainable embedding component (to capture
spatial heterogeneity). To fill the data gap, we have - through a comprehensive
process of data collection, integration, and augmentation - created a
large-scale publicly available database of accident information named
US-Accidents. By employing the US-Accidents dataset and through an extensive
set of experiments across several large cities, we have evaluated our proposal
against several baselines. Our analysis and results show significant
improvements to predict rare accident events. Further, we have shown the impact
of traffic information, time, and points-of-interest data for real-time
accident prediction.Comment: In Proceedings of the 27th ACM SIGSPATIAL, International Conference
on Advances in Geographic Information Systems (2019). arXiv admin note:
substantial text overlap with arXiv:1906.0540
Toward nanofluids of ultra-high thermal conductivity
The assessment of proposed origins for thermal conductivity enhancement in nanofluids signifies the importance of particle morphology and coupled transport in determining nanofluid heat conduction and thermal conductivity. The success of developing nanofluids of superior conductivity depends thus very much on our understanding and manipulation of the morphology and the coupled transport. Nanofluids with conductivity of upper Hashin-Shtrikman (H-S) bound can be obtained by manipulating particles into an interconnected configuration that disperses the base fluid and thus significantly enhancing the particle-fluid interfacial energy transport. Nanofluids with conductivity higher than the upper H-S bound could also be developed by manipulating the coupled transport among various transport processes, and thus the nature of heat conduction in nanofluids. While the direct contributions of ordered liquid layer and particle Brownian motion to the nanofluid conductivity are negligible, their indirect effects can be significant via their influence on the particle morphology and/or the coupled transport
DACT: Dataset of Annotated Car Trajectories
<b>DACT </b>contains two subsets of annotated car trajectories data. The dataset contains <b>50 </b>trajectories which cover about <b>13 </b>hours of driving data. In DACT, we manually specified <b>significant </b>driving patterns by using an interactive framework. A significant driving pattern can be anything like a <i>turn</i>, s<i>peed-up</i>, <i>slow-down</i>, etc. The annotation process consists of a crowd-sourcing task followed by comprehensive aggregation phases. The aggregation is done by two different strategies: Strict and Easy. For the first one, we used some strict constraints to aggregate crowd-sourcing results, while we used flexible constraints to generate the second subset of DACT. More information about this dataset may be find here: https://arxiv.org/abs/1705.05219 .<div>Please cite this paper "<b>Trajectory Annotation by Discovering Driving Patterns (UrbanGIS'17</b><b>)</b>", available at https://dl.acm.org/citation.cfm?doid=3152178.3152184, if you want to use this dataset.</div