1,077 research outputs found
A burst search for gravitational waves from binary black holes
Compact binary coalescence (CBC) is one of the most promising sources of
gravitational waves. These sources are usually searched for with matched
filters which require accurate calculation of the GW waveforms and generation
of large template banks. We present a complementary search technique based on
algorithms used in un-modeled searches. Initially designed for detection of
un-modeled bursts, which can span a very large set of waveform morphologies,
the search algorithm presented here is constrained for targeted detection of
the smaller subset of CBC signals. The constraint is based on the assumption of
elliptical polarisation for signals received at the detector. We expect that
the algorithm is sensitive to CBC signals in a wide range of masses, mass
ratios, and spin parameters. In preparation for the analysis of data from the
fifth LIGO-Virgo science run (S5), we performed preliminary studies of the
algorithm on test data. We present the sensitivity of the search to different
types of simulated CBC waveforms. Also, we discuss how to extend the results of
the test run into a search over all of the current LIGO-Virgo data set.Comment: 12 pages, 4 figures, 2 tables, submitted for publication in CQG in
the special issue for the conference proceedings of GWDAW13; corrected some
typos, addressed some minor reviewer comments one section restructured and
references updated and correcte
'GEOGRAPHICAL INDICATION'AS A STRATEGY FOR MARKETING OF HANDLOOM PRODUCTS: EVIDENCE FROM SAREE INDUSTRY
Geographic indication of goods, a part of intellectual property rights, identifies the location of a commodity. Various categories may be used to categorise these things, such as agricultural, natural commodities, manufactured goods, food items, textiles, and handicrafts. Sarees are one of the nation's more well-known and pricey handcrafted goods. The current study intends to investigate the market potential and efficiency of the Indian handloom saree business. The product comparison demonstrates that every brand has its own marketing plan. Additionally, the prices of these sarees vary widely between brands and are not uniform
The study outcome of bouquet technique for the management of displaced boxer's fracture
Background: Fifth metacarpal neck fracture is also called Boxer's fracture. Most commonly occurs due to aggression behaviour that result in punch on a wall with a clenched first. If there is a displacement of boxer’s fracture more than 500 then it has to be managed operatively. We here present the outcome of bouquet technique that we used to operate the 80 cases of 5th metacarpal neck fracture.
Methods: We studied and did follow up of the 80, 5th metacarpal neck fracture that managed by bouquet technique. Clinical and radiological assessment was done at 4weeks and 6 weeks and 12 weeks. Total active motion, radiography and complication were noted.
Results: Out of 80 patients that were studied 72 got excellent results and 8 got fair results. Whereas one patient got infection and 2 got adventitious bursitis at the entry site which requires k wire removal.
Conclusions: The technique of antegrade intramedullary 3 kirschners wire in management of 5th metacarpal neck fracture is safe, simple, soft tissue sparing, minimally invasive technique with excellent functional and cosmetic outcome with minimal complications
Predictive modeling of die filling of the pharmaceutical granules using the flexible neural tree
In this work, a computational intelligence (CI) technique named flexible neural tree (FNT) was developed to predict die filling performance of pharmaceutical granules and to identify significant die filling process variables. FNT resembles feedforward neural network, which creates a tree-like structure by using genetic programming. To improve accuracy, FNT parameters were optimized by using differential evolution algorithm. The performance of the FNT-based CI model was evaluated and compared with other CI techniques: multilayer perceptron, Gaussian process regression, and reduced error pruning tree. The accuracy of the CI model was evaluated experimentally using die filling as a case study. The die filling experiments were performed using a model shoe system and three different grades of microcrystalline cellulose (MCC) powders (MCC PH 101, MCC PH 102, and MCC DG). The feed powders were roll-compacted and milled into granules. The granules were then sieved into samples of various size classes. The mass of granules deposited into the die at different shoe speeds was measured. From these experiments, a dataset consisting true density, mean diameter (d50), granule size, and shoe speed as the inputs and the deposited mass as the output was generated. Cross-validation (CV) methods such as 10FCV and 5x2FCV were applied to develop and to validate the predictive models. It was found that the FNT-based CI model (for both CV methods) performed much better than other CI models. Additionally, it was observed that process variables such as the granule size and the shoe speed had a higher impact on the predictability than that of the powder property such as d50. Furthermore, validation of model prediction with experimental data showed that the die filling behavior of coarse granules could be better predicted than that of fine granules
Data-Driven Thermal Anomaly Detection in Large Battery Packs
The early detection and tracing of anomalous operations in battery packs are
critical to improving performance and ensuring safety. This paper presents a
data-driven approach for online anomaly detection in battery packs that uses
real-time voltage and temperature data from multiple Li-ion battery cells.
Mean-based residuals are generated for cell groups and evaluated using
Principal Component Analysis. The evaluated residuals are then thresholded
using a cumulative sum control chart to detect anomalies. The mild external
short circuits associated with cell balancing are detected in the voltage
signals and necessitate voltage retraining after balancing. Temperature
residuals prove to be critical, enabling anomaly detection of module balancing
events within 14 min that are unobservable from the voltage residuals.
Statistical testing of the proposed approach is performed on the experimental
data from a battery electric locomotive injected with model-based anomalies.
The proposed anomaly detection approach has a low false-positive rate and
accurately detects and traces the synthetic voltage and temperature anomalies.
The performance of the proposed approach compared with direct thresholding of
mean-based residuals shows a 56% faster detection time, 42% fewer false
negatives, and 60% fewer missed anomalies while maintaining a comparable
false-positive rate
Implications For The Origin Of GRB 051103 From LIGO Observations
We present the results of a LIGO search for gravitational waves (GWs)
associated with GRB 051103, a short-duration hard-spectrum gamma-ray burst
(GRB) whose electromagnetically determined sky position is coincident with the
spiral galaxy M81, which is 3.6 Mpc from Earth. Possible progenitors for
short-hard GRBs include compact object mergers and soft gamma repeater (SGR)
giant flares. A merger progenitor would produce a characteristic GW signal that
should be detectable at the distance of M81, while GW emission from an SGR is
not expected to be detectable at that distance. We found no evidence of a GW
signal associated with GRB 051103. Assuming weakly beamed gamma-ray emission
with a jet semi-angle of 30 deg we exclude a binary neutron star merger in M81
as the progenitor with a confidence of 98%. Neutron star-black hole mergers are
excluded with > 99% confidence. If the event occurred in M81 our findings
support the the hypothesis that GRB 051103 was due to an SGR giant flare,
making it the most distant extragalactic magnetar observed to date.Comment: 8 pages, 3 figures. For a repository of data used in the publication,
go to: https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=15166 . Also see
the announcement for this paper on ligo.org at:
http://www.ligo.org/science/Publication-GRB051103/index.ph
Stacked Search for Gravitational Waves from the 2006 SGR 1900+14 Storm
We present the results of a LIGO search for short-duration gravitational
waves (GWs) associated with the 2006 March 29 SGR 1900+14 storm. A new search
method is used, "stacking'' the GW data around the times of individual
soft-gamma bursts in the storm to enhance sensitivity for models in which
multiple bursts are accompanied by GW emission. We assume that variation in the
time difference between burst electromagnetic emission and potential burst GW
emission is small relative to the GW signal duration, and we time-align GW
excess power time-frequency tilings containing individual burst triggers to
their corresponding electromagnetic emissions. We use two GW emission models in
our search: a fluence-weighted model and a flat (unweighted) model for the most
electromagnetically energetic bursts. We find no evidence of GWs associated
with either model. Model-dependent GW strain, isotropic GW emission energy
E_GW, and \gamma = E_GW / E_EM upper limits are estimated using a variety of
assumed waveforms. The stacking method allows us to set the most stringent
model-dependent limits on transient GW strain published to date. We find E_GW
upper limit estimates (at a nominal distance of 10 kpc) of between 2x10^45 erg
and 6x10^50 erg depending on waveform type. These limits are an order of
magnitude lower than upper limits published previously for this storm and
overlap with the range of electromagnetic energies emitted in SGR giant flares.Comment: 7 pages, 3 figure
Performance Analysis Techniques for Real-time Broadband RFI Filtering System of uGMRT
Electromagnetic radiation from human activities, known as man-made Radio
Frequency Interference (RFI), adversely affects radio astronomy observations.
In the vicinity of the Upgraded Giant Metrewave Radio Telescope (uGMRT) array,
the sparking on power lines is the major cause of interference at observing
frequencies less than 800 MHz. A real-time broadband RFI detection and
filtering system is implemented as part of the uGMRT wideband signal processing
backend to mitigate the effect of broadband RFI. Performance analysis
techniques used for testing and commissioning the system for observations in
the beamformer and correlator modes of the uGMRT are presented. The concept and
implementation of recording simultaneous unfiltered and filtered data along
with data analysis and interpretation is illustrated using an example. For the
beamformer mode, spectrogram, single spectral channel, and its Fourier
transform is used for performance analysis whereas, in the correlator mode, the
cross-correlation function, closure phase, and visibilities from the
simultaneously recorded unfiltered and filtered is carried out. These
techniques are used for testing the performance of the broadband RFI filter and
releasing it for uGMRT users.Comment: 14 pages, 5 figure
Search for gravitational waves associated with the InterPlanetary Network short gamma ray bursts
We outline the scientific motivation behind a search for gravitational waves
associated with short gamma ray bursts detected by the InterPlanetary Network
(IPN) during LIGO's fifth science run and Virgo's first science run. The IPN
localisation of short gamma ray bursts is limited to extended error boxes of
different shapes and sizes and a search on these error boxes poses a series of
challenges for data analysis. We will discuss these challenges and outline the
methods to optimise the search over these error boxes.Comment: Methods paper; Proceedings for Eduardo Amaldi 9 Conference on
Gravitational Waves, July 2011, Cardiff, U
- …
