Indian Institute of Technology Bombay

About: Indian Institute of Technology Bombay is a education organization based out in Mumbai, India. It is known for research contribution in the topics: Catalysis & Computer science. The organization has 16756 authors who have published 33588 publications receiving 570559 citations.

Harnessing Context Incongruity for Sarcasm Detection

Abstract: The relationship between context incongruity and sarcasm has been studied in linguistics. We present a computational system that harnesses context incongruity as a basis for sarcasm detection. Our statistical sarcasm classifiers incorporate two kinds of incongruity features: explicit and implicit. We show the benefit of our incongruity features for two text forms tweets and discussion forum posts. Our system also outperforms two past works (with Fscore improvement of 10-20%). We also show how our features can capture intersentential incongruity.

A review of solar thermochemical processes

Abstract: This paper reviews development in the field of solar thermochemical processing by considering experimental demonstrations, reactor technology development, thermodynamic, economic and life cycle analyses. The review then builds on these aspects and compares various solar thermochemical processes. Solar upgrading of carbon feed has been demonstrated on pilot scale. It is observed that for the thermochemical cycles, only iron and ceria based redox pair have been demonstrated on pilot scale. For industrial applications, solar thermochemical production of zinc, upgrading of landfill gas and organic waste have been demonstrated on pilot scale. However, long term performance data of these pilot plants is not reported in literature. Thermodynamic comparison reveals that the processes involving upgrading of carbon feed have energy and exergy efficiency at 50–90% and 46–48% respectively. Multistep thermochemical cycles operating at 900–1200 K have energy efficiency of 34–38%. Metal oxide redox pair based thermochemical cycles operating at 1900–2300 K have energy and exergy efficiencies of 12–32% and 20–36% respectively. Methane reforming and lime production processes have chemical efficiencies of 55% and 35% respectively and have demonstrated better performance than other solar thermochemical processes. A few processes like solar gasification of solid carbon feed have demonstrated lower chemical efficiency of around 10% even at pilot scale. The hydrogen production cost for solar upgrading of fossil fuels is estimated at 3.21–6.10$/kg and is lower than thermochemical cycles at 7.17–19.26$/kg and CSP driven electrolysis at 3.15–10.23$/kg. It is observed that there is limited actual data and significant uncertainty in cost. Under these circumstances, it is recommended that initial screening of processes be done by net energy, material and life cycle analysis.

Beam energy dependence of moments of the net-charge multiplicity distributions in Au+Au collisions at RHIC

Abstract: We report the first measurements of the moments-mean (M), variance (sigma(2)), skewness (S), and kurtosis (kappa)-of the net-charge multiplicity distributions at midrapidity in Au + Au collisions at seven energies, ranging from root s(NN) = 7.7 to 200 GeV, as a part of the Beam Energy Scan program at RHIC. The moments are related to the thermodynamic susceptibilities of net charge, and are sensitive to the location of the QCD critical point. We compare the products of the moments, sigma(2)/M, S sigma, and kappa sigma(2), with the expectations from Poisson and negative binomial distributions (NBDs). The S sigma values deviate from the Poisson baseline and are close to the NBD baseline, while the kappa sigma(2) values tend to lie between the two. Within the present uncertainties, our data do not show nonmonotonic behavior as a function of collision energy. These measurements provide a valuable tool to extract the freeze-out parameters in heavy-ion collisions by comparing with theoretical models.

Charged-particle multiplicity measurement in proton-proton collisions at $\sqrt{s}=7$ TeV with ALICE at LHC

Abstract: Charged-particle production was studied in proton-proton collisions collected at the LHC with the ALICE detector at centre-of-mass energies 0.9 TeV and 2.36 TeV in the pseudorapidity range vertical bar eta vertical bar < 1.4. In the central region (vertical bar eta vertical bar < 0.5), at 0.9 TeV, we measure charged-particle pseudo-rapidity density dN(ch)/d eta = 3.02 +/- 0.01(stat.)(-0.05)(+0.08)(syst.) for inelastic interactions, and dN(ch)/d eta = 3.58 +/- 0.01 (stat.)(-0.12)(+0.12)(syst.) for non-single-diffractive interactions. At 2.36 TeV, we find dN(ch)/d eta = 3.77 +/- 0.01(stat.)(-0.12)(+0.25)(syst.) for inelastic, and dN(ch)/d eta = 4.43 +/- 0.01(stat.)(-0.12)(+0.17)(syst.) for non-single-diffractive collisions. The relative increase in charged-particle multiplicity from the lower to higher energy is 24.7% +/- 0.5%(stat.)(-2.8)(+5.7)%(syst.) for inelastic and 23.7% +/- 0.5%(stat.)(-1.1)(+4.6)%(syst.) for non-single-diffractive interactions. This increase is consistent with that reported by the CMS collaboration for non-single-diffractive events and larger than that found by a number of commonly used models. The multiplicity distribution was measured in different pseudorapidity intervals and studied in terms of KNO variables at both energies. The results are compared to proton-antiproton data and to model predictions.

Reduced-Order Model and Stability Analysis of Low-Voltage DC Microgrid

Abstract: Depleting fossil fuels, increasing energy demand, and need for high-reliability power supply motivate the use of dc microgrids. This paper analyzes the stability of low-voltage dc microgrid systems. Sources are controlled using a droop-based decentralized controller. Various components of the system have been modeled. A linearized system model is derived using small-signal approximation. The stability of the system is analyzed by identifying the eigenvalues of the system matrix. The sufficiency condition for stable operation of the system is derived. It provides upper bound on droop constants and is useful during planning and designing of dc microgrids. Furthermore, the sensitivity of system poles to variation in cable resistance and inductance is identified. It is proved that the poles move further inside the negative real plane with a decrease in inductance or an increase in resistance. The method proposed in this paper is applicable to any interconnecting structure of sources and loads. The results obtained by analysis are verified by detailed simulation study. Root locus plots are included to confirm the movement of system poles. The viability of the model is confirmed by experimental results from a scaled-down laboratory prototype of a dc microgrid developed for the purpose.