1,075 research outputs found
Vacuum Geometry and the Search for New Physics
We propose a new guiding principle for phenomenology: special geometry in the
vacuum space. New algorithmic methods which efficiently compute geometric
properties of the vacuum space of N=1 supersymmetric gauge theories are
described. We illustrate the technique on subsectors of the MSSM. The fragility
of geometric structure that we find in the moduli space motivates
phenomenologically realistic deformations of the superpotential, while arguing
against others. Special geometry in the vacuum may therefore signal the
presence of string physics underlying the low-energy effective theory.Comment: 8 pages, LaTeX; v2: revised title, minor changes in wording,
reference adde
Modified SPLICE and its Extension to Non-Stereo Data for Noise Robust Speech Recognition
In this paper, a modification to the training process of the popular SPLICE
algorithm has been proposed for noise robust speech recognition. The
modification is based on feature correlations, and enables this stereo-based
algorithm to improve the performance in all noise conditions, especially in
unseen cases. Further, the modified framework is extended to work for
non-stereo datasets where clean and noisy training utterances, but not stereo
counterparts, are required. Finally, an MLLR-based computationally efficient
run-time noise adaptation method in SPLICE framework has been proposed. The
modified SPLICE shows 8.6% absolute improvement over SPLICE in Test C of
Aurora-2 database, and 2.93% overall. Non-stereo method shows 10.37% and 6.93%
absolute improvements over Aurora-2 and Aurora-4 baseline models respectively.
Run-time adaptation shows 9.89% absolute improvement in modified framework as
compared to SPLICE for Test C, and 4.96% overall w.r.t. standard MLLR
adaptation on HMMs.Comment: Submitted to Automatic Speech Recognition and Understanding (ASRU)
2013 Worksho
Transition from confined to bulk dynamics in symmetric star-linear polymer mixtures
We report on the linear viscoelastic properties of mixtures comprising
multiarm star (as model soft colloids) and long linear chain homopolymers in a
good solvent. In contrast to earlier works, we investigated symmetric mixtures
(with a size ratio of 1) and showed that the polymeric and colloidal responses
can be decoupled. The adopted experimental protocol involved probing the linear
chain dynamics in different star environments. To this end, we studied mixtures
with different star mass fraction, which was kept constant while linear chains
were added and their entanglement plateau modulus () and terminal
relaxation time () were measured as functions of their concentration.
Two distinct scaling regimes were observed for both and : at low
linear polymer concentrations, a weak concentration dependence was observed,
that became even weaker as the fraction of stars in the mixtures increased into
the star glassy regime. On the other hand, at higher linear polymer
concentrations, the classical entangled polymer scaling was recovered. Simple
scaling arguments show that the threshold crossover concentration between the
two regimes corresponds to the maximum osmotic star compression and signals the
transition from confined to bulk dynamics. These results provide the needed
ingredients to complete the state diagram of soft colloid-polymer mixtures and
investigate their dynamics at large polymer-colloid size ratios. They also
offer an alternative way to explore aspects of the colloidal glass transition
and the polymer dynamics in confinement. Finally, they provide a new avenue to
tailor the rheology of soft composites.Comment: 9 Figure
Restriction enzymes use a 24 dimensional coding space to recognize 6 base long DNA sequences
Restriction enzymes recognize and bind to specific sequences on invading
bacteriophage DNA. Like a key in a lock, these proteins require many contacts
to specify the correct DNA sequence. Using information theory we develop an
equation that defines the number of independent contacts, which is the
dimensionality of the binding. We show that EcoRI, which binds to the sequence
GAATTC, functions in 24 dimensions. Information theory represents messages as
spheres in high dimensional spaces. Better sphere packing leads to better
communications systems. The densest known packing of hyperspheres occurs on the
Leech lattice in 24 dimensions. We suggest that the single protein EcoRI
molecule employs a Leech lattice in its operation. Optimizing density of sphere
packing explains why 6 base restriction enzymes are so common.Comment: Version 1: 31 pages, 3 figures, 1 table; Version 2: 33 pages, 3
figures, 1 table, responses to reviewers, new ref
The Library of Babel
We show that heavy pure states of gravity can appear to be mixed states to
almost all probes. Our arguments are made for Schwarzschild black
holes using the field theory dual to string theory in such spacetimes. Our
results follow from applying information theoretic notions to field theory
operators capable of describing very heavy states in gravity. For certain
supersymmetric states of the theory, our account is exact: the microstates are
described in gravity by a spacetime ``foam'', the precise details of which are
invisible to almost all probes.Comment: 7 pages, 1 figure, Essay receiving honorable mention in the 2005
Gravity Research Foundation essay competitio
Pred-NBV: Prediction-guided Next-Best-View for 3D Object Reconstruction
Prediction-based active perception has shown the potential to improve the
navigation efficiency and safety of the robot by anticipating the uncertainty
in the unknown environment. The existing works for 3D shape prediction make an
implicit assumption about the partial observations and therefore cannot be used
for real-world planning and do not consider the control effort for
next-best-view planning. We present Pred-NBV, a realistic object shape
reconstruction method consisting of PoinTr-C, an enhanced 3D prediction model
trained on the ShapeNet dataset, and an information and control effort-based
next-best-view method to address these issues. Pred-NBV shows an improvement of
25.46% in object coverage over the traditional methods in the AirSim simulator,
and performs better shape completion than PoinTr, the state-of-the-art shape
completion model, even on real data obtained from a Velodyne 3D LiDAR mounted
on DJI M600 Pro.Comment: 6 pages, 4 figures, 2 tables. Accepted to IROS 202
MAP-NBV: Multi-agent Prediction-guided Next-Best-View Planning for Active 3D Object Reconstruction
We propose MAP-NBV, a prediction-guided active algorithm for 3D
reconstruction with multi-agent systems. Prediction-based approaches have shown
great improvement in active perception tasks by learning the cues about
structures in the environment from data. But these methods primarily focus on
single-agent systems. We design a next-best-view approach that utilizes
geometric measures over the predictions and jointly optimizes the information
gain and control effort for efficient collaborative 3D reconstruction of the
object. Our method achieves 22.75% improvement over the prediction-based
single-agent approach and 15.63% improvement over the non-predictive
multi-agent approach. We make our code publicly available through our project
website: http://raaslab.org/projects/MAPNBV/Comment: 7 pages, 7 figures, 2 tables. Submitted to MRS 202
Significance of tissue microbiopsies in fine needle aspiration cytology
Background: Fine Needle Aspiration Cytology smears prepared through conventional method, often contain well preserved viable tissue fragments which are intact (Tissue Micro biopsies). They will provide information on the tissue architecture and contribute to the tumour ontogeny.Methods: A prospective study of significance of tissue micro biopsies in FNAC were studied and interpreted in the Cytopathology laboratory of Department of Pathology, Tirunelveli Medical College, Tirunelveli. 100 cases with clinically palpable Swellings were studied.Results: Out of 100 cases, 82% of cases were coming under the category of conventional FNAC, 10% of the cases were USG guided and 8% were falling under CT guided FNAC. The organs with highest yield of micro biopsies were lymph nodes 34 cases (34%) followed by breast 24 cases, thyroid 11 cases, lung 8 cases, salivary gland 7 cases, liver and bone and soft tissue 4 cases each, abdominal mass 3cases, pancreas 2 cases, and single case each of ovary, spleen, anterior mediastinum. Of the total 100 cases, 56% of the cases were malignant and 44% of the cases were benign. Among the 56 malignant tumours 41(73.2%) cases were primary tumours and 15cases (26.8%) were metastatic tumours.Conclusions: FNA smears containing micro biopsies help in diagnosis, typing of tumour and predicting possible primary sites in cases of metastatic tumours which were not possible by cytology alone. Hence, this technique can be used to increase the diagnostic accuracy of FNAC if put into practice
ANOMALY DETECTION OF EVENTS IN CROWDED ENVIRONMENT AND STUDY OF VARIOUS BACKGROUND SUBTRACTION METHODS
Anomalous behavior detection and localization in videos of the crowded area that is specific from a dominant pattern are obtained. Appearance and motion information are taken into account to robustly identify different kinds of an anomaly considering a wide range of scenes. Our concept based on a histogram of oriented gradients and Markov random field easily captures varying dynamic of the crowded environment.Histogram of oriented gradients along with well-known Markov random field will effectively recognize and characterizes each frame of each scene. Anomaly detection using artificial neural network consist both appearance and motion features which extract within spatio temporal domain of moving pixels that ensures robustness to local noise and thus increases accuracy in detection of a local anomaly with low computational cost.To extract a region of interest we have to subtract background. Background subtraction is done by various methods like Weighted moving mean, Gaussian mixture model, Kernel density estimation.
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