26,106 research outputs found
A conjecture on the primitive degree of Tensors
In this paper, we prove: Let A be a nonnegative primitive tensor with order m
and dimension n. Then its primitive degree R(A)\leq (n-1)^2+1, and the upper
bound is sharp. This confirms a conjecture of Shao [7].Comment: 8 page
Local Visual Microphones: Improved Sound Extraction from Silent Video
Sound waves cause small vibrations in nearby objects. A few techniques exist
in the literature that can extract sound from video. In this paper we study
local vibration patterns at different image locations. We show that different
locations in the image vibrate differently. We carefully aggregate local
vibrations and produce a sound quality that improves state-of-the-art. We show
that local vibrations could have a time delay because sound waves take time to
travel through the air. We use this phenomenon to estimate sound direction. We
also present a novel algorithm that speeds up sound extraction by two to three
orders of magnitude and reaches real-time performance in a 20KHz video.Comment: Accepted to BMVC 201
Spatio-Temporal Action Detection with Cascade Proposal and Location Anticipation
In this work, we address the problem of spatio-temporal action detection in
temporally untrimmed videos. It is an important and challenging task as finding
accurate human actions in both temporal and spatial space is important for
analyzing large-scale video data. To tackle this problem, we propose a cascade
proposal and location anticipation (CPLA) model for frame-level action
detection. There are several salient points of our model: (1) a cascade region
proposal network (casRPN) is adopted for action proposal generation and shows
better localization accuracy compared with single region proposal network
(RPN); (2) action spatio-temporal consistencies are exploited via a location
anticipation network (LAN) and thus frame-level action detection is not
conducted independently. Frame-level detections are then linked by solving an
linking score maximization problem, and temporally trimmed into spatio-temporal
action tubes. We demonstrate the effectiveness of our model on the challenging
UCF101 and LIRIS-HARL datasets, both achieving state-of-the-art performance.Comment: Accepted at BMVC 2017 (oral
Cascaded Boundary Regression for Temporal Action Detection
Temporal action detection in long videos is an important problem.
State-of-the-art methods address this problem by applying action classifiers on
sliding windows. Although sliding windows may contain an identifiable portion
of the actions, they may not necessarily cover the entire action instance,
which would lead to inferior performance. We adapt a two-stage temporal action
detection pipeline with Cascaded Boundary Regression (CBR) model.
Class-agnostic proposals and specific actions are detected respectively in the
first and the second stage. CBR uses temporal coordinate regression to refine
the temporal boundaries of the sliding windows. The salient aspect of the
refinement process is that, inside each stage, the temporal boundaries are
adjusted in a cascaded way by feeding the refined windows back to the system
for further boundary refinement. We test CBR on THUMOS-14 and TVSeries, and
achieve state-of-the-art performance on both datasets. The performance gain is
especially remarkable under high IoU thresholds, e.g. map@tIoU=0.5 on THUMOS-14
is improved from 19.0% to 31.0%
SL(2,C) gravity on noncommutative space with Poisson structure
The Einstein's gravity theory can be formulated as an SL(2,C) gauge theory in
terms of spinor notations. In this paper, we consider a noncommutative space
with the Poisson structure and construct an SL(2,C) formulation of gravity on
such a space. Using the covariant coordinate technique, we build a gauge
invariant action in which, according to the Seiberg-Witten map, the physical
degrees of freedom are expressed in terms of their commutative counterparts up
to the first order in noncommutative parameters.Comment: 12 pages, no figures; v2: 13 pages, clarifications and references
added; v3: clarifications added; v4: more clarifications and references
added, final version to appear in Phys. Rev.
Indeliable exhibition: Yellow river boat (2018): Trap (2018)
This exhibition is one of two that make up a cultural and artistic exchange project with Xi'an Art Museum, Xi'an City, Shaanxi Province, China; Waikato Museum, Hamilton, NZ; and Wintec researchers (Hamilton, NZ). Themes of exchange, community, identity and location were explored by the various practitioners involved in the project.
These two sculptural works examine cultural practices of food gathering in relationship to community
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