276,601 research outputs found
Robust recognition and segmentation of human actions using HMMs with missing observations
This paper describes the integration of missing observation data with hidden Markov models to create a framework that is able to segment and classify individual actions from a stream of human motion using an incomplete 3D human pose estimation. Based on this framework, a model is trained to automatically segment and classify an activity sequence into its constituent subactions during inferencing. This is achieved by introducing action labels into the observation vector and setting these labels as missing data during inferencing, thus forcing the system to infer the probability of each action label. Additionally, missing data provides recognition-level support for occlusions and imperfect silhouette segmentation, permitting the use of a fast (real-time) pose estimation that delegates the burden of handling undetected limbs onto the action recognition system. Findings show that the use of missing data to segment activities is an accurate and elegant approach. Furthermore, action recognition can be accurate even when almost half of the pose feature data is missing due to occlusions, since not all of the pose data is important all of the time
Abacus models for parabolic quotients of affine Weyl groups
We introduce abacus diagrams that describe minimal length coset
representatives in affine Weyl groups of types B, C, and D. These abacus
diagrams use a realization of the affine Weyl group of type C due to Eriksson
to generalize a construction of James for the symmetric group. We also describe
several combinatorial models for these parabolic quotients that generalize
classical results in affine type A related to core partitions.Comment: 28 pages, To appear, Journal of Algebra. Version 2: Updated with
referee's comment
Smart Footwear Insole for Recognition of Foot Pronation and Supination Using Neural Networks
Abnormal foot postures during gait are common sources of pain and pathologies of the
lower limbs. Measurements of foot plantar pressures in both dynamic and static conditions can detect
these abnormal foot postures and prevent possible pathologies. In this work, a plantar pressure
measurement system is developed to identify areas with higher or lower pressure load. This system
is composed of an embedded system placed in the insole and a user application. The instrumented
insole consists of a low-power microcontroller, seven pressure sensors and a low-energy bluetooth
module. The user application receives and shows the insole pressure information in real-time and,
finally, provides information about the foot posture. In order to identify the different pressure states
and obtain the final information of the study with greater accuracy, a Deep Learning neural network
system has been integrated into the user application. The neural network can be trained using a
stored dataset in order to obtain the classification results in real-time. Results prove that this system
provides an accuracy over 90% using a training dataset of 3000+ steps from 6 different users.Ministerio de EconomÃa y Competitividad TEC2016-77785-
NTU RGB+D 120: A Large-Scale Benchmark for 3D Human Activity Understanding
Research on depth-based human activity analysis achieved outstanding
performance and demonstrated the effectiveness of 3D representation for action
recognition. The existing depth-based and RGB+D-based action recognition
benchmarks have a number of limitations, including the lack of large-scale
training samples, realistic number of distinct class categories, diversity in
camera views, varied environmental conditions, and variety of human subjects.
In this work, we introduce a large-scale dataset for RGB+D human action
recognition, which is collected from 106 distinct subjects and contains more
than 114 thousand video samples and 8 million frames. This dataset contains 120
different action classes including daily, mutual, and health-related
activities. We evaluate the performance of a series of existing 3D activity
analysis methods on this dataset, and show the advantage of applying deep
learning methods for 3D-based human action recognition. Furthermore, we
investigate a novel one-shot 3D activity recognition problem on our dataset,
and a simple yet effective Action-Part Semantic Relevance-aware (APSR)
framework is proposed for this task, which yields promising results for
recognition of the novel action classes. We believe the introduction of this
large-scale dataset will enable the community to apply, adapt, and develop
various data-hungry learning techniques for depth-based and RGB+D-based human
activity understanding. [The dataset is available at:
http://rose1.ntu.edu.sg/Datasets/actionRecognition.asp]Comment: IEEE Transactions on Pattern Analysis and Machine Intelligence
(TPAMI
RGB-D-based Action Recognition Datasets: A Survey
Human action recognition from RGB-D (Red, Green, Blue and Depth) data has
attracted increasing attention since the first work reported in 2010. Over this
period, many benchmark datasets have been created to facilitate the development
and evaluation of new algorithms. This raises the question of which dataset to
select and how to use it in providing a fair and objective comparative
evaluation against state-of-the-art methods. To address this issue, this paper
provides a comprehensive review of the most commonly used action recognition
related RGB-D video datasets, including 27 single-view datasets, 10 multi-view
datasets, and 7 multi-person datasets. The detailed information and analysis of
these datasets is a useful resource in guiding insightful selection of datasets
for future research. In addition, the issues with current algorithm evaluation
vis-\'{a}-vis limitations of the available datasets and evaluation protocols
are also highlighted; resulting in a number of recommendations for collection
of new datasets and use of evaluation protocols
Using tracked mobile sensors to make maps of environmental effects
We present a study the results of a study of environmental carbon monoxide pollution that has uses a set of
tracked, mobile pollution sensors. The motivating concept is that we will be able to map pollution and other
properties of the real world a fine scale if we can deploy a large set of sensors with members of the general public
who would carry them as they go about their normal everyday activities. To prove the viability of this concept
we have to demonstrate that data gathered in an ad-hoc manner is reliable enough in order to allow us to
build interesting geo-temporal maps.
We present a trial using a small number of global positioning system-tracked CO sensors. From analysis of raw
GPS logs we find some well-known spatial and temporal properties of CO. Further, by processing the GPS logs
we can find fine-grained variations in pollution readings such as when crossing roads. We then discuss the space
of possibilities that may be enabled by tracking sensors around the urban environment – both in getting at personal
experience of properties of the environment and in making summative maps to predict future conditions.
Although we present a study of CO, the techniques will be applicable to other environmental properties such as
radio signal strength, noise, weather and so on
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