Indian Institute of Technology Madras

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  • Person
    Mainak Saha
  • Publication
    KLAUS-Tr: Knowledge & learning-based unit focused arithmetic word problem solver for transfer cases
    Solving the Arithmetic Word Problems (AWPs) using AI techniques has attracted much attention in recent years. We feel that the current AWP solvers are under-utilizing the relevant domain knowledge. We present a knowledge- and learning-based system that effectively solves AWPs of a specific type - those that involve transfer of objects from one agent to another (Transfer Cases (TC)). We represent the knowledge relevant to these problems as TC Ontology. The sentences in TC-AWPs contain information of essentially four types: before-transfer, transfer, after-transfer, and query. Our system (KLAUS-Tr) uses statistical classifier to recognize the types of sentences. The sentence types guide the information extraction process used to identify the agents, quantities, units, types of objects, and the direction of transfer from the AWP text. The extracted information is represented as an RDF graph that utilizes the TC Ontology terminology. To solve the given AWP, we utilize semantic web rule language (SWRL) rules that capture the knowledge about how object transfer affects the RDF graph of the AWP. Using the TC ontology, we also analyze if the given problem is consistent or otherwise. The different ways in which TC-AWPs can be inconsistent are encoded as SWRL rules. Thus, KLAUS-Tr can identify if the given AWP is invalid and accordingly notify the user. Since the existing datasets do not have inconsistent AWPs, we create AWPs of this type and augment the datasets. We have implemented KLAUS-Tr and tested it on TC-type AWPs drawn from the All-Arith and other datasets. We find that TC-AWPs constitute about 40% of the AWPs in a typical dataset like All-Arith. Our system achieves an impressive accuracy of 92%, thus improving the state-of-the-art significantly. We plan to extend the system to handle AWPs that contain multiple transfers of objects and also offer explanations of the solutions.
  • Publication
    Development of the CMS detector for the CERN LHC Run 3
    (2024-05-01)
    Tumasyan, A.
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    Adam, W.
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    Andrejkovic, J. W.
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    Bergauer, T.
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    Chatterjee, S.
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    Damanakis, K.
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    Dragicevic, M.
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    Del Valle, A. Escalante
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    Hussain, P. S.
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    Jeitler, M.
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    Krammer, N.
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    Lechner, L.
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    Liko, D.
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    Mikulec, I.
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    Paulitsch, P.
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    Pitters, F. M.
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    Schieck, J.
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    Schöfbeck, R.
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    Schwarz, D.
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    Templ, S.
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    Waltenberger, W.
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    Wulz, C. E.
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    Darwish, M. R.
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    Janssen, T.
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    Kello, T.
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    Rejeb Sfar, H.
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    Van Mechelen, P.
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    Bols, E. S.
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    D’Hondt, J.
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    De Moor, A.
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    Delcourt, M.
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    El Faham, H.
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    Lowette, S.
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    Moortgat, S.
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    Morton, A.
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    Müller, D.
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    Sahasransu, A. R.
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    Tavernier, S.
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    Van Doninck, W.
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    Vannerom, D.
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    Clerbaux, B.
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    De Lentdecker, G.
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    Favart, L.
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    Jaramillo, J.
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    Lee, K.
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    Mahdavikhorrami, M.
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    Makarenko, I.
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    Malara, A.
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    Paredes, S.
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    Pétré, L.
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    Postiau, N.
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    Starling, E.
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    Thomas, L.
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    Bemden, M. Vanden
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    Velde, C. Vander
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    Vanlaer, P.
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    Dobur, D.
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    Knolle, J.
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    Lambrecht, L.
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    Mestdach, G.
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    Niedziela, M.
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    Rendón, C.
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    Roskas, C.
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    Samalan, A.
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    Skovpen, K.
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    Tytgat, M.
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    Van Den Bossche, N.
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    Vermassen, B.
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    Wezenbeek, L.
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    Benecke, A.
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    Bethani, A.
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    Bruno, G.
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    Bury, F.
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    Caputo, C.
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    David, P.
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    Delaere, C.
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    Donertas, I. S.
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    Giammanco, A.
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    Jaffel, K.
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    Jain, Sa
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    Lemaitre, V.
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    Mondal, K.
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    Prisciandaro, J.
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    Taliercio, A.
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    Tran, T. T.
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    Vischia, P.
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    Wertz, S.
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    Alves, G. A.
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    Coelho, E.
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    Hensel, C.
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    Moraes, A.
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    Teles, P. Rebello
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    Júnior, W. L.Aldá
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    Pereira, M. Alves Gallo
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    Filho, M. Barroso Ferreira
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    Malbouisson, H. Brandao
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    Carvalho, W.
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    Chinellato, J.
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    Da Costa, E. M.
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    Da Silveira, G. G.
    Since the initial data taking of the CERN LHC, the CMS experiment has undergone substantial upgrades and improvements. This paper discusses the CMS detector as it is configured for the third data-taking period of the CERN LHC, Run 3, which started in 2022. The entire silicon pixel tracking detector was replaced. A new powering system for the superconducting solenoid was installed. The electronics of the hadron calorimeter was upgraded. All the muon electronic systems were upgraded, and new muon detector stations were added, including a gas electron multiplier detector. The precision proton spectrometer was upgraded. The dedicated luminosity detectors and the beam loss monitor were refurbished. Substantial improvements to the trigger, data acquisition, software, and computing systems were also implemented, including a new hybrid CPU/GPU farm for the high-level trigger.
  • Publication
    On Rotation Distance of Rank Bounded Trees
    (2024-05-31)
    Jayalal Sarma, Anoop S.K.M.
    Computing the rotation distance between two binary trees with n internal nodes efficiently (in poly(n) time) is a long standing open question in the study of height balancing in tree data structures. In this paper, we initiate the study of this problem bounding the rank of the trees given at the input (defined in [1] in the context of decision trees). We define the rank-bounded rotation distance between two given full binary trees T1 and T2 (with n internal nodes) of rank at most r = max{rank(T1), rank(T2)}, denoted by dR(T1, T2), as the length of the shortest sequence of rotations that transforms T1 to T2 with the restriction that the intermediate trees must be of rank at most r. We show that the rotation distance problem reduces in polynomial time to the rank bounded rotation distance problem. This motivates the study of the problem in the combinatorial and algorithmic frontiers. Observing that trees with rank 1 coincide exactly with skew trees (full binary trees where every internal node has at least one leaf as a child), we show the following results in this frontier: • We presentan O(n2) time algorithm for computing dR(T1, T2). That is, when the given full binary trees are skew trees (we call this variant the skew rotation distance problem) - where the intermediate trees are restricted to be skew as well In particular, our techniques imply that for any two skew trees dR(T1, T2) ≤ n2. • We show the following upper bound: for any two full binary trees T1 and T2 of rank r1 and r2 respectively, we have that: dR(T1, T2) ≤ n2(1 + (2n + 1)(r1 + r2 − 2)) where r = max{r1, r2}. This bound is asymptotically tight for r = 1. En route to our proof of the above theorems, we associate full binary trees to permutations and relate the rotation operation on trees to transpositions in the corresponding permutations. We give exact combinatorial characterizations of permutations that correspond to full binary trees and full skew binary trees under this association. We also precisely characterize the transpositions that correspond to the set of rotations in full binary trees. We also study bi-variate polynomials associated with binary trees (introduced by [2]), and show characterizations and algorithms for computing rotation distances for the case of full skew trees using them.
  • Publication
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  • Publication
    Estimation of energy dissipation in Lap lap _Joints joints using Scaling scaling Approachapproach
    (01-01-2017)
    Naik, Abhay
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    Under high loads, it is vital to predict the vibration levels in assemblies in the early design phase. Today there is a good understanding of the dynamics of individual components, but this confidence reduces considerably for a large assembly with joints in it. One of the key issues is the localized damping introduced due to the joints.joints. The prediction of the damping due to micro and macro sliding is very important. Joint damping prediction due to micro and macro sliding in joints is important. This paper describes a method to estimate the damping in an actual lap joint from a scaled physical model of a joint. This has the advantage of using lower capacity equipment for estimating joint damping by inducing slip under various loading conditions. To start with a detailed nonlinear Finite Element Analysis (FEA) of the lap joint was is _used to estimate the damping due to micro and macro sliding taking place in the jointfrom the hysteresis curve generated under various loadings; the damping is due to micro and macro sliding taking place in the joint. _The results from the simulations verified confirm the power law dependence of the energy dissipation in joints on excitation amplitudes reported in the literature. The dependence of dissipation energy on Joint joint pre-load, friction coefficient was is _also examined. The FEA simulations confirmed the possibility of using scaling to gather estimates of damping under various loads in lap joints. This is useful during the early design phase when actual hardware is unavailable. Validation of the FEA is currently underway using an experimental setup. _If successful, this idea will can _help change assembly based vibration prediction from a ‘retrospective or tuning’ based approach towards a more predictive based approach.
  • Publication
    A comparative study of a novel multi-swirl lean direct injection and conventional single swirl gas turbine burner for reduced emissions and combustion instability
    (01-01-2017)
    Deepika, V.
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    Bharathi, Raja N.
    A gas turbine combustor design must take into consideration performance parameters like combustion efficiency, pressure drop across the combustor, stability limits, exit temperature distribution, emissions, combustion instability, etc. for a good design. This paper discusses the comparison of a novel multi-swirl burner* employing lean direct injection (LDI) with a conventional premixed single swirl gas turbine engine burner in terms of the various performance parameters. Pressure drop is highly reduced and the stability limits are enhanced using the novel multi-swirl LDI burner developed. The LDI burner achieves a uniform mixing of fuel and air, eliminating hot spots in combustion; leading to reduced overall emissions. Results also show that the LDI burner is less susceptible to combustion instability. These advantages of the multi-swirl LDI burner make it a potential contender to be employed in the combustor of gas turbine engines.
  • Publication
    Identification of hard exudates in retinal images
    (01-01-2017)
    Dhiravidachelvi, E.
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    Rajamani, V.
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    Janakiraman, P. A.
    A new procedure for identification of the hard exudates is described in this Paper. Images are sorted into as many as 15 types using the maximum value of the hue in an image. Hue (h) at a point is defined as the ratio of green (g) to red (r) intensities. Given an image, the type-number is assigned to it. The exudates are also identified by using the hue, h. The varying intensities have been taken care of by the linear fit obeyed by the plot: h = m*g+c. A modified hue variable ‘Bh’ is used to eliminate the soft exudates which have a blue component, by fitting lines like Bh=w1*h+w2. Very low intensity yellow coloured patches which do not qualify as hard exudates are removed by a discriminating threshold ‘de’. The parameters like (m, c), (w1,w2), de are listed for the 15 types, in a Look up Table derived from experiments. The table entries vary in a structured manner. The tables can further be simplified as expressions if desired.
  • Publication
    Gold Nanomaterials: Recent Advances in Cancer Theranostics
    (01-01-2017)
    Sudhakar, S.
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    Santhosh, P. B.
    This chapter describes the potential of various shapes of gold nanomaterials such as nanoparticles, nanorods, nanostars, nanocages, and nanoshells in cancer nanotheranostics, i.e., both as diagnostic and therapeutic agent. This study includes the synthesis of different gold nanomaterials using several methods like chemical-, green-, and microbial-mediated synthesis. The ability of gold nanomaterials to absorb light in the near-infrared region and transform it into heat and their unique optical properties make them a promising tool in photothermal cancer therapy. Herein, we present the recent advances and the ability of gold nanomaterials to show its multiple roles in the field of cancer biology.