72 research outputs found
Fast Dawid-Skene: A Fast Vote Aggregation Scheme for Sentiment Classification
Many real world problems can now be effectively solved using supervised
machine learning. A major roadblock is often the lack of an adequate quantity
of labeled data for training. A possible solution is to assign the task of
labeling data to a crowd, and then infer the true label using aggregation
methods. A well-known approach for aggregation is the Dawid-Skene (DS)
algorithm, which is based on the principle of Expectation-Maximization (EM). We
propose a new simple, yet effective, EM-based algorithm, which can be
interpreted as a `hard' version of DS, that allows much faster convergence
while maintaining similar accuracy in aggregation. We show the use of this
algorithm as a quick and effective technique for online, real-time sentiment
annotation. We also prove that our algorithm converges to the estimated labels
at a linear rate. Our experiments on standard datasets show a significant
speedup in time taken for aggregation - upto 8x over Dawid-Skene and
6x over other fast EM methods, at competitive accuracy performance. The
code for the implementation of the algorithms can be found at
https://github.com/GoodDeeds/Fast-Dawid-SkeneComment: 8 pages, 5 tables, 1 figure, KDD Workshop on Issues of Sentiment
Discovery and Opinion Mining (WISDOM) 201
Novel optically active lead-free relaxor ferroelectric (Ba0.6Bi0.2Li0.2)TiO3
We discovered a near room temperature lead-free relaxor-ferroelectric
(Ba0.6Bi0.2Li0.2)TiO3 (BBLT) having A-site compositional disordered ABO3
perovskite structure. Microstructure-property relations revealed that the
chemical inhomogeneities and development of local polar nano regions (PNRs) are
responsible for dielectric dispersion as a function of probe frequencies and
temperatures. Rietveld analysis indicates mixed crystal structure with 80%
tetragonal structure (space group P4mm) and 20% orthorhombic structure (space
group Amm2) which is confirmed by the high resolution transmission electron
diffraction pattern. Dielectric constant and tangent loss dispersion with and
without illumination of light obey nonlinear Vogel-Fulture relation. It shows
slim polarization-hysteresis (P-E) loops and excellent displacement
coefficients (d33 ~ 233 pm/V) near room temperature, which gradually diminish
near the maximum dielectric dispersion temperature (Tm). The underlying physics
for light-sensitive dielectric dispersion was probed by X-ray photon
spectroscopy (XPS) which strongly suggests that mixed valence of bismuth ions,
especially Bi5+ ions, are responsible for most of the optically active centers.
Ultraviolet photoemission measurements showed most of the Ti ions are in 4+
states and sit at the centers of the TiO6 octahedra, which along with
asymmetric hybridization between O 2p and Bi 6s orbitals appears to be the main
driving force for net polarization. This BBLT material may open a new path for
environmental friendly lead-free relaxor-ferroelectric research.Comment: 23 pages, 5 figure
Effect of SEN immersion depth on mold flow profile and slag entrapment during continuous casting of steel
Mold flux entrapment during continuous casting of steel contributes to both surface and sub-surface defects in the final product. Continuous casting operating parameters such as casting speed, SEN immersion depth, SEN port geometry, argon flow, and mold EMS significantly affect the mold flow conditions and flow profile. During continuous casting operation, SEN immersion depth is continuously varied to avoid localized erosion of SEN, and it impacts the flow dynamics in the mold. In the present work, water modeling studies were carried out for a wide range of mold widths (1200-1800 mm) and casting speeds (0.8-1.4 m/min) on a 0.5 scaled down water model to optimize casting speed for different combinations of SEN immersion depth and mold width. Results from water modeling were further validated using nail board studies in the actual plant. A safe operating matrix was identified from these experiments to avoid mold slag entrapment during continuous casting
Disruptive Technology in Digital Notice Board using Flutter
In early days, notice boards were used to place notices which is a very hard process. First a teacher has to make a notice on his computer and edit to make it attractive then he must get it approved by the HOD. Then when it gets approved, he must print it then the teacher must go to every notice board and physically pin the notice on the notice board Which is a very hard and time-consuming process. In order to make this experience easy we are proposing a digital notice board Which will make the process very easy and very efficient. Our main aim is to make information easy to access to students and at the same time make it easy for teachers to build a notice using their phones and the templates provided on the app
Instruments of RT-2 Experiment onboard CORONAS-PHOTON and their test and evaluation II: RT-2/CZT payload
Cadmium Zinc Telluride (CZT) detectors are high sensitivity and high
resolution devices for hard X-ray imaging and spectroscopic studies. The new
series of CZT detector modules (OMS40G256) manufactured by Orbotech Medical
Solutions (OMS), Israel, are used in the RT-2/CZT payload onboard the
CORONAS-PHOTON satellite. The CZT detectors, sensitive in the energy range of
20 keV to 150 keV, are used to image solar flares in hard X-rays. Since these
modules are essentially manufactured for commercial applications, we have
carried out a series of comprehensive tests on these modules so that they can
be confidently used in space-borne systems. These tests lead us to select the
best three pieces of the 'Gold' modules for the RT-2/CZT payload. This paper
presents the characterization of CZT modules and the criteria followed for
selecting the ones for the RT-2/CZT payload. The RT-2/CZT payload carries,
along with three CZT modules, a high spatial resolution CMOS detector for high
resolution imaging of transient X-ray events. Therefore, we discuss the
characterization of the CMOS detector as well.Comment: 26 pages, 19 figures, Accepted for publication in Experimental
Astronomy (in press
Giant enhancement in ferroelectric polarization under illumination
AK acknowledges the CSIR-MIST (PSC-0111) project for their financial assistance. Hitesh Borkar would like to acknowledge the UGC (SRF) to provide fellowship to carry out Ph.D program.We report optical enhancement in polarization and dielectric constant near room temperature in Pb0.6Li0.2Bi0.2Zr0.2Ti0.8O3 (PLBZT) electro-ceramics; these are doubly substituted members of the most important commercial ferroelectric PbZr0.2Ti0.8O3 (PZT:20/80). Partial (40%) substitution of equal amounts of Li+1 and Bi+3 in PZT: 20/80 retains the PZT tetragonal structure with space group P4 mm. Under illumination of white light and weak 405 nm near-ultraviolet laser light (30 mW), an unexpectedly large (200-300%) change in polarization and displacement current was observed. Light also changes the dc conduction current density by one to two orders of magnitude with a large switchable open circuit voltage (Vocv ∼ 2 V) and short circuit current (Jscc∼ 5 × 10−8 A). The samples show a photo-current ON/OFF ratio of order 6:1 under illumination of weak light.PostprintPeer reviewe
Deadline-aware fair scheduling for multi-tenant crowd-powered systems
Crowdsourcing has become an integral part of many systems and services that deliver high-quality results for complex tasks such as data linkage, schema matching, and content annotation. A standard function of such crowd-powered systems is to publish a batch of tasks on a crowdsourcing platform automatically and to collect the results once the workers complete them. Currently, these systems provide limited guarantees over the execution time, which is problematic for many applications. Timely completion may even be impossible to guarantee due to factors specific to the crowdsourcing platform, such as the availability of workers and concurrent tasks. In our previous work, we presented the architecture of a crowd-powered system that reshapes the interaction mechanism with the crowd. Specifically, we studied a push-crowdsourcing model whereby the workers receive tasks instead of selecting them from a portal. Based on this interaction model, we employed scheduling techniques similar to those found in distributed computing infrastructures to automate the task assignment process. In this work, we first devise a generic scheduling strategy that supports both fairness and deadline-awareness. Second, to complement the proof-of-concept experiments previously performed with the crowd, we present an extensive set of simulations meant to analyze the properties of the proposed scheduling algorithms in an environment with thousands of workers and tasks. Our experimental results show that, by accounting for human factors, micro-task scheduling can achieve fairness for best-effort batches and boosts production batches
Qualitative and quantitative determination of phytochemicals from flowers of Spanish Cherry tree
The present enquiry was intended to analyze the phytochemicals qualitatively and quantitatively from flowers of Spanish cherry tree. Flower powder was extracted using polar and nonpolar solvent by soxhlet apparatus. Percentage yield of crude extracts was determined and further the extracts were subjected to analyze the phytochemicals qualitatively and quantitatively by standard procedure. Qualitative analysis showed the absence of alkaloids while presences of tannins, saponins, terpenoids, steroids, glycosides, flavonoids, phenols. Quantitative estimation of phytochemicals was determined using standard curve. Result revealed that the tannin content was 4.3±0.01 (mgTAE /gm), flavanols content was 0.28±0.05 (mgQE/gm). Saponins content was 3.6±0.7 % and terpenoids content was 1.47±0.37 %. A well conducted studies on phytochemicals revealed that they are vital for humans because they provide protection against a variety of ailments. Therefore, the present study is aimed to analyze phytochemicals qualitatively and quantitatively.
Keywords: Phytochemicals, Tannins, Saponins, Flavanols, Terpenoid
Pancreatic cancer is marked by complement-high blood monocytes and tumor-associated macrophages
Pancreatic ductal adenocarcinoma (PDA) is accompanied by reprogramming of the local microenvironment, but changes at distal sites are poorly understood. We implanted biomaterial scaffolds, which act as an artificial premetastatic niche, into immunocompetent tumor-bearing and control mice, and identified a unique tumor-specific gene expression signature that includes high expression of C1qa, C1qb, Trem2, and Chil3 Single-cell RNA sequencing mapped these genes to two distinct macrophage populations in the scaffolds, one marked by elevated C1qa, C1qb, and Trem2, the other with high Chil3, Ly6c2 and Plac8 In mice, expression of these genes in the corresponding populations was elevated in tumor-associated macrophages compared with macrophages in the normal pancreas. We then analyzed single-cell RNA sequencing from patient samples, and determined expression of C1QA, C1QB, and TREM2 is elevated in human macrophages in primary tumors and liver metastases. Single-cell sequencing analysis of patient blood revealed a substantial enrichment of the same gene signature in monocytes. Taken together, our study identifies two distinct tumor-associated macrophage and monocyte populations that reflects systemic immune changes in pancreatic ductal adenocarcinoma patients
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