YouTube AV 50K: An Annotated Corpus for Comments in Autonomous Vehicles

With one billion monthly viewers, and millions of users discussing and sharing opinions, comments below YouTube videos are rich sources of data for opinion mining and sentiment analysis. We introduce the YouTube AV 50K dataset, a freely-available collections of more than 50,000 YouTube comments and metadata below autonomous vehicle (AV)-related videos. We describe its creation process, its content and data format, and discuss its possible usages. Especially, we do a case study of the first self-driving car fatality to evaluate the dataset, and show how we can use this dataset to better understand public attitudes toward self-driving cars and public reactions to the accident. Future developments of the dataset are also discussed.Comment: in Proceedings of the Thirteenth International Joint Symposium on Artificial Intelligence and Natural Language Processing (iSAI-NLP 2018

Seismic fragility analysis of reinforced concrete bridges with chloride induced corrosion subjected to spatially varying ground motion

This paper studies the time-dependent seismic fragility of reinforced concrete bridges with chloride induced corrosion under spatially varying ground motions. The time-varying characteristic of the chloride corrosion current density and the uncertainties related to the structural, material and corrosion parameters are both considered in the probabilistic finite element modeling of the example RC bridge at different time steps during its life-cycle. Spatially varying ground motions at different bridge supports are stochastically simulated and used as inputs in the fragility analysis. Seismic fragility curves of the corroded RC bridge at different time steps are generated using the probabilistic seismic demand analysis (PSDA) method. Numerical results indicate that both chloride induced corrosion and ground motion spatial variations have a significant effect on the bridge structural seismic fragility. As compared to the intact bridge, the mean peak ground accelerations (PGAs) of the fragility curves of the RC bridge decrease by approximately 40% after 90 years since the initiation of corrosion. Moreover, the effect of ground motion spatial variations changes along with the process of chloride induced corrosion owing to the structural stiffness degradation. Neglecting seismic ground motion spatial variations may not lead to an accurate estimation of the lifetime seismic fragility of RC bridges with chloride induced corrosion

Theoretical modeling and numerical simulation of seismic motions at seafloor

This paper proposes a modelling and simulation method of seafloor seismic motions on offshore sites, which are composed of the base rock, the porous soil layers and the seawater layer, based on the fundamental hydrodynamics equations and one-dimensional wave propagation theory. The base rock motions are assumed to consist of P- and S-waves and are modelled by the seismological model in southwest of Western Australia (SWWA). The transfer functions of the offshore site are calculated by incorporating the derived dynamic-stiffness matrix of seawater layer into the total stiffness matrix. The effect of water saturation on the P-wave velocity and Poisson’s ratio of subsea soil layers are also considered in the model. Both onshore and seafloor seismic motions are stochastically simulated. The comparison results show that the seafloor vertical motions are significantly suppressed near the P-wave resonant frequencies of the upper seawater layer, which makes their intensities much lower than the onshore vertical motions. Owing to their compliance with the characteristics of available seafloor earthquake recordings, the proposed method can be used to simulate seafloor motions for offshore structural seismic analyses

Modeling and Simulation of Spatially Correlated Ground Motions at Multiple Onshore and Offshore Sites

A simulation method of spatially correlated seafloor motions is proposed by considering the influences of seawater on the seafloor motions and their spatial variations at different subsea sites. The offshore site transfer functions are theoretically derived using the fundamental hydrodynamics and one-dimensional wave propagation theory. Three-dimensional spatially varying ground motions on the surfaces of multiple onshore and offshore sites are synthesized based on the spectral representation method and the calculated site transfer functions. A pair of onshore and seafloor recordings from the same earthquake event is employed to examine the basic characteristics of simulated onshore and seafloor motions

Music Sequence Prediction with Mixture Hidden Markov Models

Recommendation systems that automatically generate personalized music playlists for users have attracted tremendous attention in recent years. Nowadays, most music recommendation systems rely on item-based or user-based collaborative filtering or content-based approaches. In this paper, we propose a novel mixture hidden Markov model (HMM) for music play sequence prediction. We compare the mixture model with state-of-the-art methods and evaluate the predictions quantitatively and qualitatively on a large-scale real-world dataset in a Kaggle competition. Results show that our model significantly outperforms traditional methods as well as other competitors. We conclude by envisioning a next-generation music recommendation system that integrates our model with recent advances in deep learning, computer vision, and speech techniques, and has promising potential in both academia and industry.Comment: Accepted to the 4th International Conference on Artificial Intelligence and Applications (AI 2018

Correcting soft errors online in fast fourier transform

While many algorithm-based fault tolerance (ABFT) schemes have been proposed to detect soft errors offline in the fast Fourier transform (FFT) after computation finishes, none of the existing ABFT schemes detect soft errors online before the computation finishes. This paper presents an online ABFT scheme for FFT so that soft errors can be detected online and the corrupted computation can be terminated in a much more timely manner. We also extend our scheme to tolerate both arithmetic errors and memory errors, develop strategies to reduce its fault tolerance overhead and improve its numerical stability and fault coverage, and finally incorporate it into the widely used FFTW library - one of the today's fastest FFT software implementations. Experimental results demonstrate that: (1) the proposed online ABFT scheme introduces much lower overhead than the existing offline ABFT schemes; (2) it detects errors in a much more timely manner; and (3) it also has higher numerical stability and better fault coverage

PRELIMINARY STUDY OF TRAINING COMPONENTS ON SENSORIMOTOR SYSTEM IN TAI CHI

The purpose of this study was to identify if Tai Chi (TC) movements are full with the training components on sensorimotor system by movement kinematics and electromyography (EMG) analysis. Two TC masters performed a typical TC movement "brush knees and twist steps" twice. Motion analysis showed that joint angles (ankles, knees and hips) of eight different postures, height and velocity of center of gravity (C.G.) of the whole movement had no significant difference in two trials. The results indicated that the TC masters had good awareness of joint position and movement and spatial position sense. Moreover, EMG analysis showed that muscles activated from full relaxation to vigorous contraction and the similar EMG patterns of each muscle in two trials suggested the good training effect of TC on muscle coordinative contraction