284,365 research outputs found
IDENTIFICATION OF COVER SONGS USING INFORMATION THEORETIC MEASURES OF SIMILARITY
13 pages, 5 figures, 4 tables. v3: Accepted version13 pages, 5 figures, 4 tables. v3: Accepted version13 pages, 5 figures, 4 tables. v3: Accepted versio
Mining Heterogeneous Multivariate Time-Series for Learning Meaningful Patterns: Application to Home Health Telecare
For the last years, time-series mining has become a challenging issue for
researchers. An important application lies in most monitoring purposes, which
require analyzing large sets of time-series for learning usual patterns. Any
deviation from this learned profile is then considered as an unexpected
situation. Moreover, complex applications may involve the temporal study of
several heterogeneous parameters. In that paper, we propose a method for mining
heterogeneous multivariate time-series for learning meaningful patterns. The
proposed approach allows for mixed time-series -- containing both pattern and
non-pattern data -- such as for imprecise matches, outliers, stretching and
global translating of patterns instances in time. We present the early results
of our approach in the context of monitoring the health status of a person at
home. The purpose is to build a behavioral profile of a person by analyzing the
time variations of several quantitative or qualitative parameters recorded
through a provision of sensors installed in the home
Light Curve Modulation of Low Mass Stars in K2. I. Identification of 508 Fast Rotators in the Solar Neighborhood
The K2 mission is targeting large numbers of nearby (d<100 pc) GKM dwarfs
selected from the SUPERBLINK proper motion survey (mu>40 mas yr^-1, V<20).
Additionally, the mission is targeting low-mass, high proper motion stars
associated with the local (d<500 pc) Galactic halo population also selected
from SUPERBLINK. K2 campaigns 0 through 8 monitored a total of 27,382 of these
cool main-sequence stars. We used the auto-correlation function to search for
fast rotators by identifying short-period photometric modulations in the K2
light curves. We identified 508 candidate fast rotators with rotation periods
<4 days that show light curve modulations consistent with star spots. Their
kinematics show low average transverse velocities, suggesting they are part of
the young disk population. A subset (13) of the fast rotators are found among
those targets with colors and kinematics consistent with the local Galactic
halo population and may represent stars spun up by tidal interactions in close
binary systems. We further demonstrate the M dwarf fast rotators selected from
the K2 light curves are significantly more likely to have UV excess, and
discuss the potential of the K2 mission to identify new nearby young GKM dwarfs
on the basis of their fast rotation rates. Finally, we discuss the possible use
of local halo stars as fiducial, non-variable sources in the Kepler fields.Comment: 14 pages, 14 figures, to appear in the Astronomical Journal (AJ
Measuring spike train synchrony
Estimating the degree of synchrony or reliability between two or more spike
trains is a frequent task in both experimental and computational neuroscience.
In recent years, many different methods have been proposed that typically
compare the timing of spikes on a certain time scale to be fixed beforehand.
Here, we propose the ISI-distance, a simple complementary approach that
extracts information from the interspike intervals by evaluating the ratio of
the instantaneous frequencies. The method is parameter free, time scale
independent and easy to visualize as illustrated by an application to real
neuronal spike trains obtained in vitro from rat slices. In a comparison with
existing approaches on spike trains extracted from a simulated Hindemarsh-Rose
network, the ISI-distance performs as well as the best time-scale-optimized
measure based on spike timing.Comment: 11 pages, 13 figures; v2: minor modifications; v3: minor
modifications, added link to webpage that includes the Matlab Source Code for
the method (http://inls.ucsd.edu/~kreuz/Source-Code/Spike-Sync.html
HyperLEDA. III. The catalogue of extragalactic distances
We present the compilation catalogue of redshift-independent distances
included in the HyperLEDA database. It is actively maintained to be up-to-date,
and the current version counts 6640 distance measurements for 2335 galaxies
compiled from 430 published articles. Each individual series is recalibrated
onto a common distance scale based on a carefully selected set of high-quality
measurements. This information together with data on HI line-width, central
velocity dispersion, magnitudes, diameters, and redshift is used to derive a
homogeneous distance estimate and physical properties of galaxies, such as
their absolute magnitudes and intrinsic size.Comment: accepted to A&
Sequential Complexity as a Descriptor for Musical Similarity
We propose string compressibility as a descriptor of temporal structure in
audio, for the purpose of determining musical similarity. Our descriptors are
based on computing track-wise compression rates of quantised audio features,
using multiple temporal resolutions and quantisation granularities. To verify
that our descriptors capture musically relevant information, we incorporate our
descriptors into similarity rating prediction and song year prediction tasks.
We base our evaluation on a dataset of 15500 track excerpts of Western popular
music, for which we obtain 7800 web-sourced pairwise similarity ratings. To
assess the agreement among similarity ratings, we perform an evaluation under
controlled conditions, obtaining a rank correlation of 0.33 between intersected
sets of ratings. Combined with bag-of-features descriptors, we obtain
performance gains of 31.1% and 10.9% for similarity rating prediction and song
year prediction. For both tasks, analysis of selected descriptors reveals that
representing features at multiple time scales benefits prediction accuracy.Comment: 13 pages, 9 figures, 8 tables. Accepted versio
Splitting hybrid Make-To-Order and Make-To-Stock demand profiles
In this paper a demand time series is analysed to support Make-To-Stock (MTS)
and Make-To-Order (MTO) production decisions. Using a purely MTS production
strategy based on the given demand can lead to unnecessarily high inventory
levels thus it is necessary to identify likely MTO episodes.
This research proposes a novel outlier detection algorithm based on special
density measures. We divide the time series' histogram into three clusters. One
with frequent-low volume covers MTS items whilst a second accounts for high
volumes which is dedicated to MTO items. The third cluster resides between the
previous two with its elements being assigned to either the MTO or MTS class.
The algorithm can be applied to a variety of time series such as stationary and
non-stationary ones.
We use empirical data from manufacturing to study the extent of inventory
savings. The percentage of MTO items is reflected in the inventory savings
which were shown to be an average of 18.1%.Comment: demand analysis; time series; outlier detection; production strategy;
Make-To-Order(MTO); Make-To-Stock(MTS); 15 pages, 9 figure
Single-vehicle data of highway traffic - a statistical analysis
In the present paper single-vehicle data of highway traffic are analyzed in
great detail. By using the single-vehicle data directly empirical time-headway
distributions and speed-distance relations can be established. Both quantities
yield relevant information about the microscopic states. Several fundamental
diagrams are also presented, which are based on time-averaged quantities and
compared with earlier empirical investigations. In the remaining part
time-series analyses of the averaged as well as the single-vehicle data are
carried out. The results will be used in order to propose objective criteria
for an identification of the different traffic states, e.g. synchronized
traffic.Comment: 12 pages, 19 figures, RevTe
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