31,937 research outputs found
The output distribution of important LULU-operators
Two procedures to compute the output distribution phi_S of certain stack
filters S (so called erosion-dilation cascades) are given. One rests on the
disjunctive normal form of S and also yields the rank selection probabilities.
The other is based on inclusion-exclusion and e.g. yields phi_S for some
important LULU-operators S. Properties of phi_S can be used to characterize
smoothing properties of S. One of the methods discussed also allows for the
calculation of the reliability polynomial of any positive Boolean function
(e.g. one derived from a connected graph).Comment: 20 pages, up to trivial differences this is the final version to be
published in Quaestiones Mathematicae 201
The Ensemble Kalman Filter: A Signal Processing Perspective
The ensemble Kalman filter (EnKF) is a Monte Carlo based implementation of
the Kalman filter (KF) for extremely high-dimensional, possibly nonlinear and
non-Gaussian state estimation problems. Its ability to handle state dimensions
in the order of millions has made the EnKF a popular algorithm in different
geoscientific disciplines. Despite a similarly vital need for scalable
algorithms in signal processing, e.g., to make sense of the ever increasing
amount of sensor data, the EnKF is hardly discussed in our field.
This self-contained review paper is aimed at signal processing researchers
and provides all the knowledge to get started with the EnKF. The algorithm is
derived in a KF framework, without the often encountered geoscientific
terminology. Algorithmic challenges and required extensions of the EnKF are
provided, as well as relations to sigma-point KF and particle filters. The
relevant EnKF literature is summarized in an extensive survey and unique
simulation examples, including popular benchmark problems, complement the
theory with practical insights. The signal processing perspective highlights
new directions of research and facilitates the exchange of potentially
beneficial ideas, both for the EnKF and high-dimensional nonlinear and
non-Gaussian filtering in general
Kajian motivasi ekstrinsik di antara Pelajar Lepasan Sijil dan Diploma Politeknik Jabatan Kejuruteraan Awam KUiTTHO
Kajian ini dijalankan untuk menyelidiki pengaruh dorongan keluarga, cara pengajaran pensyarah, pengaruh rakan sebaya dan kemudahan infrastruktur terhadap motivasi ekstrinsik bagi pelajar tahun tiga dan tahun empat lepasan sijil dan diploma politeknik Jabatan Kejuruteraan Awain Kolej Universiti Teknologi Tun Hussein Onn. Sampel kajian ini beijumlah 87 orang bagi pelajar lepasan sijil politeknik dan 38 orang bagi lepasan diploma politeknik. Data kajian telah diperolehi melalui borang soal selidik dan telah dianalisis menggunakan perisian SPSS (Statical Package For Sciences). Hasil kajian telah dipersembahkan dalam bentuk jadual dan histohgrapi. Analisis kajian mendapati bahawa kedua-dua kumpulan setuju bahawa faktor-faktor di atas memberi kesan kepada motivasi ekstrinsik mereka. Dengan kata lain faktpr-faktor tersebut penting dalam membentuk pelajar mencapai kecemerlangan akademik
Calibration Uncertainty for Advanced LIGO's First and Second Observing Runs
Calibration of the Advanced LIGO detectors is the quantification of the
detectors' response to gravitational waves. Gravitational waves incident on the
detectors cause phase shifts in the interferometer laser light which are read
out as intensity fluctuations at the detector output. Understanding this
detector response to gravitational waves is crucial to producing accurate and
precise gravitational wave strain data. Estimates of binary black hole and
neutron star parameters and tests of general relativity require well-calibrated
data, as miscalibrations will lead to biased results. We describe the method of
producing calibration uncertainty estimates for both LIGO detectors in the
first and second observing runs.Comment: 15 pages, 21 figures, LIGO DCC P160013
Detailed comparison of Milky Way models based on stellar population synthesis and SDSS star counts at the north Galactic pole
We test the ability of the TRILEGAL and Besancon models to reproduce the CMD
of SDSS data at the north Galactic pole (NGP). We show that a Hess diagram
analysis of colour-magnitude diagrams is much more powerful than luminosity
functions (LFs) in determining the Milky Way structure. We derive a
best-fitting TRILEGAL model to simulate the NGP field in the (g-r, g) CMD of
SDSS filters via Hess diagrams. For the Besancon model, we simulate the LFs and
Hess diagrams in all SDSS filters. We use a chi2 analysis and determine the
median of the relative deviations in the Hess diagrams to quantify the quality
of the fits by the TRILEGAL models and the Besancon model in comparison and
compare this with the Just-Jahreiss model. The input isochrones in the
colour-absolute magnitude diagrams of the thick disc and halo are tested via
the observed fiducial isochrones of globular clusters (GCs). We find that the
default parameter set lacking a thick disc component gives the best
representation of the LF in TRILEGAL. The Hess diagram reveals that a
metal-poor thick disc is needed. In the Hess diagram, the median relative
deviation of the TRILEGAL model and the SDSS data amounts to 25 percent,
whereas for the Just-Jahreiss model the deviation is only 5.6 percent. The
isochrone analysis shows that the representation of the MS of (at least
metal-poor) stellar populations in the SDSS system is reliable. In contrast,
the RGBs fail to match the observed fiducial sequences of GCs. The Besancon
model shows a similar median relative deviation of 26 percent in (g-r, g). In
the u band, the deviations are larger. There are significant offsets between
the isochrone set used in the Besancon model and the observed fiducial
isochrones. In contrast to Hess diagrams, LFs are insensitive to the detailed
structure of the Milky Way components due to the extended spatial distribution
along the line of sight.Comment: 21 pages, 17 figures and 5 tables. Accepted by publication of A&
Distributed classifier based on genetically engineered bacterial cell cultures
We describe a conceptual design of a distributed classifier formed by a
population of genetically engineered microbial cells. The central idea is to
create a complex classifier from a population of weak or simple classifiers. We
create a master population of cells with randomized synthetic biosensor
circuits that have a broad range of sensitivities towards chemical signals of
interest that form the input vectors subject to classification. The randomized
sensitivities are achieved by constructing a library of synthetic gene circuits
with randomized control sequences (e.g. ribosome-binding sites) in the front
element. The training procedure consists in re-shaping of the master population
in such a way that it collectively responds to the "positive" patterns of input
signals by producing above-threshold output (e.g. fluorescent signal), and
below-threshold output in case of the "negative" patterns. The population
re-shaping is achieved by presenting sequential examples and pruning the
population using either graded selection/counterselection or by
fluorescence-activated cell sorting (FACS). We demonstrate the feasibility of
experimental implementation of such system computationally using a realistic
model of the synthetic sensing gene circuits.Comment: 31 pages, 9 figure
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