4,531 research outputs found
Analyzing compute-intensive software performance
No full textThesis (M.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.Includes bibliographical references (p. 41).by Neeraj Gupta.M.S
Smart Grid is the Key to Enhance the Penetration of Renewable Energy into Electric Power Systems
No full textDear researchers,Due to the rapid development of renewable energy technologies because of environmental concerns, the electric power grid is experiencing a significant change. The electrical power structure is no longer a vertically integrated structure due to the large grid parity of renewables and as a result, smart grid is the key to enhance the penetration of renewable energy into electric power systems. However, due to the intermittent probabilistic nature of renewable energy sources, design and management of power are a great challenge to both power and computing industry. Furthermore, it has been anticipated that future energy structure will be “two-way streetsâ€, allowing every energy user to be not only a customer, but an energy provider as well. So, a smart grid structure is the need in the present scenario. This transition from classical power structure inevitably demands significant research for many rapidly rising issues.This Special Issue focuses on smart grid that can accommodate renewable energy into electric utility systems. The Special Issue is interested but not limited to the following issues relevant to increased renewable energy penetration:1) Prediction of sustainable energy resources.2) Stability and control of sustainable energy in supporting grid frequency and voltage.3) Steady-state and transient assessment of system, etc.4) Extent to which dispatchable generation reserves required and under what circumstances.5) Effect on reliability be compromised with increased sustainable energy penetration.6) Cost considerations with renewable’s variability7) Effect on system operating strategies with sustainable energy generation8) Effect on various measuring devices for effective monitoring and evaluation of electric power system operation, etc.Dr. Neeraj GuptaCitation: Gupta, N. (2017). Smart Grid is the Key to Enhance the Penetration of Renewable Energy into Electric Power Systems. Trends in Renewable Energy, 3(3), 1. doi:http://dx.doi.org/10.17737/tre.2017.3.3.004
Neural network based modeling and simulation for the optimization of safety logic
No full textThesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.Includes bibliographical references (leaves 46-47).by Neeraj Agarwal.M.Eng
Retracted: Robotic Process Automation use cases in academia and early implementation experiences
No full textAbstract Retraction: [Ankur Gupta, Purnendu Prabhat, Sahil Sawhney, Rajesh Gupta, Sudeep Tanwar, Neeraj Kumar, Mohammad Shabaz, Robotic Process Automation use cases in academia and early implementation experiences, IET Software 2022 (https://doi.org/10.1049/sfw2.12061)]. The above article from IET Software, published online on 19 May 2022 in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement between the Editor‐in‐Chief, Hana Chockler, the Institution of Engineering and Technology (the IET) and John Wiley and Sons Ltd. This article was published as part of a Guest Edited special issue. Following an investigation, the IET and the journal have determined that the article was not reviewed in line with the journal’s peer review standards and there is evidence that the peer review process of the special issue underwent systematic manipulation. Accordingly, we cannot vouch for the integrity or reliability of the content. As such we have taken the decision to retract the article. The authors have been informed of the decision to retract
Valorisation of Biomass Derived Furfural and Levulinic Acid by Highly Efficient Pd@ND Catalyst
No full textPalladium nanoparticles deposited on nanodiamonds (Pd/ND) have been demonstrated as efficient catalyst for the liquid phase hydrogenation of furfural and levulinic acid to furfuryl alcohol and gamma-valerolactone, respectively. The activity of the catalyst was compared to other counterparts such as Pd on activated carbon, graphene and carbon nanotubes respectively, and was found to depend on surface carbonyl groups. The highest stability of Pd/ND seems to be related to the presence of a higher amount of sp(3) carbon compared to the other supports. The developed methodology will prove beneficial for valorization of biomass derived furfural and levulinic acid in the future biorefineries
Multi-k-ic Depth Three Circuit Lower Bound
No full textIn a multi-k-ic depth three circuit every variable appears in at most k of the linear polynomials in every product gate of the circuit. This model is a natural generalization of multilinear depth three circuits that allows the formal degree of the circuit to exceed the number of underlying variables (as the formal degree of a multi-k-ic depth three circuit can be kn where n is the number of variables). The problem of proving lower bounds for depth three circuits with high formal degree has gained in importance following a work by Gupta, Kamath, Kayal and Saptharishi [7] on depth reduction to high formal degree depth three circuits. In this work, we show an exponential lower bound for multi-k-ic depth three circuits for any arbitrary constant k
Determinant Equivalence Test over Finite Fields and over Q
No full textThe determinant polynomial Det_n(x) of degree n is the determinant of a n x n matrix of formal variables. A polynomial f is equivalent to Det_n(x) over a field F if there exists a A in GL(n^2,F) such that f = Det_n(A * x). Determinant equivalence test over F is the following algorithmic task: Given black-box access to a f in F[x], check if f is equivalent to Det_n(x) over F, and if so then output a transformation matrix A in GL(n^2,F). In (Kayal, STOC 2012), a randomized polynomial time determinant equivalence test was given over F = C. But, to our knowledge, the complexity of the problem over finite fields and over Q was not well understood.
In this work, we give a randomized poly(n,log |F|) time determinant equivalence test over finite fields F (under mild restrictions on the characteristic and size of F). Over Q, we give an efficient randomized reduction from factoring square-free integers to determinant equivalence test for quadratic forms (i.e. the n=2 case), assuming GRH. This shows that designing a polynomial-time determinant equivalence test over Q is a challenging task. Nevertheless, we show that determinant equivalence test over Q is decidable: For bounded n, there is a randomized polynomial-time determinant equivalence test over Q with access to an oracle for integer factoring. Moreover, for any n, there is a randomized polynomial-time algorithm that takes input black-box access to a f in Q[x] and if f is equivalent to Det_n over Q then it returns a A in GL(n^2,L) such that f = Det_n(A * x), where L is an extension field of Q and [L : Q] <= n.
The above algorithms over finite fields and over Q are obtained by giving a polynomial-time randomized reduction from determinant equivalence test to another problem, namely the full matrix algebra isomorphism problem. We also show a reduction in the converse direction which is efficient if n is bounded. These reductions, which hold over any F (under mild restrictions on the characteristic and size of F), establish a close connection between the complexity of the two problems. This then leads to our results via applications of known results on the full algebra isomorphism problem over finite fields (Rónyai, STOC 1987 and Rónyai, J. Symb. Comput. 1990) and over Q (Ivanyos {et al}., Journal of Algebra 2012 and Babai {et al}., Mathematics of Computation 1990)
A Super-Quadratic Lower Bound for Depth Four Arithmetic Circuits
No full textWe show an Ω̃(n^2.5) lower bound for general depth four arithmetic circuits computing an explicit n-variate degree-Θ(n) multilinear polynomial over any field of characteristic zero. To our knowledge, and as stated in the survey [Amir Shpilka and Amir Yehudayoff, 2010], no super-quadratic lower bound was known for depth four circuits over fields of characteristic ≠ 2 before this work. The previous best lower bound is Ω̃(n^1.5) [Abhijat Sharma, 2017], which is a slight quantitative improvement over the roughly Ω(n^1.33) bound obtained by invoking the super-linear lower bound for constant depth circuits in [Ran Raz, 2010; Victor Shoup and Roman Smolensky, 1997].
Our lower bound proof follows the approach of the almost cubic lower bound for depth three circuits in [Neeraj Kayal et al., 2016] by replacing the shifted partials measure with a suitable variant of the projected shifted partials measure, but it differs from [Neeraj Kayal et al., 2016]’s proof at a crucial step - namely, the way "heavy" product gates are handled. Loosely speaking, a heavy product gate has a relatively high fan-in. Product gates of a depth three circuit compute products of affine forms, and so, it is easy to prune Θ(n) many heavy product gates by projecting the circuit to a low-dimensional affine subspace [Neeraj Kayal et al., 2016; Amir Shpilka and Avi Wigderson, 2001]. However, in a depth four circuit, the second (from the top) layer of product gates compute products of polynomials having arbitrary degree, and hence it was not clear how to prune such heavy product gates from the circuit. We show that heavy product gates can also be eliminated from a depth four circuit by projecting the circuit to a low-dimensional affine subspace, unless the heavy gates together account for Ω̃(n^2.5) size. This part of our argument is inspired by a well-known greedy approximation algorithm for the weighted set-cover problem
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