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809 results on '"Chakraborty, Indranil"'

203. In-Memory Computing in Emerging Memory Technologies for Machine Learning: An Overview.

Author

Roy, Kaushik, Chakraborty, Indranil, Ali, Mustafa, Ankit, Aayush, and Agrawal, Amogh

Subjects
VON Neumann architecture (Computers), MACHINE learning, DATA analysis, TECHNOLOGICAL innovations, ELECTRIC circuits
Abstract

The saturating scaling trends of CMOS technology have fuelled the exploration of emerging non-volatile memory (NVM) technologies as a promising alternative for accelerating data intensive Machine Learning (ML) workloads. To that effect, researchers have explored special-purpose accelerators based on NVM crossbar primitives. NVM crossbars have high storage density and can efficiently per-form massively parallel in-situ Matrix Vector Multiplication (MVM) operations, the key computation in ML workloads, helping over-come the memory bottleneck faced by von Neumann architectures. Despite the promises, analog computing nature of NVM crossbars can lead to functional errors due to device and circuit non-idealities such as parasitic resistances and device non-linearities. Moreover, NVM crossbars need high cost peripheral circuitry to be integrated in large scale systems. Hence, there is a need to study different levels of the design stack to realize the potential of this technology. In this paper, we present an overview of in-memory computing in NVM crossbars for ML workloads. We discuss the basic anatomy of NVM crossbars and highlight the challenges faced at the primitive level. Next, we present how the high storage density of NVM crossbars can enable spatially distributed architectures. Further, we present various modeling and evaluation tools which can effectively help us study the functionality as well as performance of NVM crossbar systems. Finally, we provide an outlook on the future research directions in this field. [ABSTRACT FROM AUTHOR]

Published
2020

204. Pre-Tibial Myxoedema

Author

Chatterjee Gobinda, Chakraborty Indranil, Banerjee Subir kumar, and Das Tushar Kanti

Subjects
Dermatology, RL1-803
Abstract

A patient of Graves†disease with unusually large asymmetrical lobulated swelling over both the skin is reported. The pathogenesis of localised myxoedema and its predilection for lower extremities is discussed.

Published
2002

222. A Luminescent Manganese PhotoCORM for CO Delivery to Cellular Targets under the Control of Visible Light

Author

Jimenez, Jorge, Chakraborty, Indranil, Dominguez, Annmarie, Martinez-Gonzalez, Jorge, Sameera, W. M. Chamil, and Mascharak, Pradip K.

Abstract

A photoactive manganese carbonyl complex derived from dansylimidazole (Imdansyl), namely, [Mn(Imdansyl)(CO)3(phen)](CF3SO3) (1), has been synthesized and structurally characterized. This is the first luminescent manganese carbonyl-based photoCORM reported in the literature. This complex exhibits CO release under the exclusive control of low-power broadband visible light. The corresponding rhenium carbonyl complex, namely, [Re(Imdansyl)(CO)3(phen)](CF3SO3) (2), has also been reported, which is luminescent but sensitive only to UV-B (λ<315 nm) light. The entry of the manganese photoCORM into the human colorectal adenocarcinoma cells (HT-29) has been demonstrated with the aid of fluorescence microscopy. Irradiation of the photoCORM-loaded cancer cells to visible light leads to a dose-dependent apoptotic cell death.

Published
2024
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223. Experimental and Theoretical Mössbauer Study of an Extended Family of [Fe8(μ4-O)4(μ-4-R-px)12X4] Clusters

Author

Zueva, Ekaterina M., Sameera, W. M. C., Piñero, Dalice M., Chakraborty, Indranil, Devlin, Eamonn, Baran, Peter, Lebruskova, Katarina, Sanakis, Yiannis, McGrady, John E., and Raptis, Raphael G.

Abstract

Six [Fe8(μ4-O)4(μ-4-R-pyrazolato)12X4] complexes containing an identical Fe8(μ4-O)4core have been structurally characterized and studied by Mössbauer spectroscopy. In each case, an inner μ4-O bridged FeIIIcubane core is surrounded by four trigonal bipyramidal iron centers, the two distinct sites occurring in a 1:1 ratio. The Mössbauer spectrum of each of the clusters consists of two quadrupole doublets, which, with one exception (X = NCS, R = H), overlap to give three absorption lines. The systematic variation of X and R causes significant changes in the Mössbauer spectra. A comparison with values for the same clusters computed using density functional theory allows us to establish an unequivocal assignment of these peaks in terms of a nested model for the overlapping doublets. The changes in Mössbauer parameters (both experimental and computed) for the 1-electron reduced species [Fe8(μ4-O)4(μ-4-Cl-pyrazolato)12Cl4]−are consistent with a redox event that is localized within the cubane core.

Published
2024
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224. NUTRITIONAL POTENTIAL, HEALTH EFFECTS AND STRUCTURAL DIVERSITY OF BIOACTIVE POLYSACCHARIDES FROM LAGENARIA SICERARIA: A REVIEW.

Author

Chakraborty, Indranil and Ghosh, Kaushik

Subjects
*LAGENARIA siceraria, *POLYSACCHARIDES, *BIOACTIVE compounds, *MEDICINAL plants, *BIOREMEDIATION
Abstract

Lagenaria siceraria (family cucurbitaceae, herbaceous climbing plant) commonly known as bottle gourd, is a medicinal plant, various parts of which have been recognized for their pharmacological potential. The fruiting body of the plant is very popular for its palatability and high nutritive values comprising almost all essential constituents for normal and sound human health. The plant is a potential source of biologically active polysaccharides. The past three decades witnessed increasing investigation of the polysaccharides isolated from different parts of the plant, and the polysaccharides were reported to show immune-enhancing, anti-tumor, antihyperlipidemic, cardioprotective, analgesic, anti-inflammatory anti-diabetic, antioxidant and hepatoprotective effects. A diversity of structures has been proposed for several polysaccharides isolated from various parts of L. siceraria. Apart from other bio active properties, this plant through the process of bioremediation can potentially detoxify soil from heavy metals. This paper reviews the nutritional composition, different health beneficial effects as well as structural variations of the polysaccharides of L. siceraria and its environmental potential. [ABSTRACT FROM AUTHOR]

Published
2020

226. Re-investigation of an octanuclear iron-oxo complex supported by 4-tbutyl-pyrazolido ligands.

Author

Lazarou, Konstantinos A., Chakraborty, Indranil, and Raptis, Raphael G.

Subjects
*SINGLE crystals, *CRYSTAL structure, *IRON ions, *MOSSBAUER spectroscopy, *IRON compounds, *CHEMISTRY, *ELECTROCHEMISTRY
Abstract

A re-investigation of the synthesis of a Fe(III)-oxo-(4- t Bu-pyrazolido) complex revealed the presence of dinuclear species, which had confused an earlier investigation of this chemistry. The synthesis and characterization of the octanuclear all-ferric compounds [Fe 8 (μ 4 -O) 4 (μ -4-R-pz) 12 Cl 4 ], R = t Bu (1) and n Bu (2) by spectroscopic (1H NMR, UV–Vis, FTIR, 57Fe-Mössbauer) and electrochemical methods are reported along with the single crystal X-ray structure determination of complex 1. These studies were undertaken in order to correct some erroneous conclusions in a recent publication (Eur. J. Inorg. Chem., 2018 , 4925–4929; Eur. J. Inorg. Chem., 2018 , 4930–4931) regarding compound 1. [ABSTRACT FROM AUTHOR]

Published
2019
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245. Anomalous GNSS Signal Strength Fluctuations during the AmphanSuper Cyclone in Eastern India on May 20, 2020

Author

Dey, Sumit, Chakraborty, Indranil, Banerjee, P., and Bose, Anindya

Abstract

Part of West Bengal, an eastern state of India, was severely affected by a super cyclone Amphan(or Umpun) on May 20, 2020, during 14:30 to 11:00 h IST with a wind speed of 155–160 km/hr and heavy rainfall. During the most intense event, Global Navigation Satellite System (GNSS) data were collected using a compact GNSS module from a location situated extremely close to the cyclone eye path. Severe fluctuation of satellite signal strength for GPS, Galileo, and Beidou signals was observed during the time in the proximity of the cyclone eye. The signal strength fluctuations caused loss of lock for the signals at the receiver resulting in a low number of used satellites and degraded position solution quality. This manuscript presents the findings which were not reported earlier. The results would be useful for understanding the effects of such events, especially for the disaster management efforts during such events in the cases where GNSS is used.

Published
2021
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246. Energy-Efficient Memories using Magneto-Electric Switching of Ferromagnets

Author

Jaiswal, Akhilesh, Chakraborty, Indranil, Roy, Kaushik, Jaiswal, Akhilesh, Chakraborty, Indranil, and Roy, Kaushik

Abstract

Voltage driven magneto-electric (ME) switching of ferro-magnets has shown potential for future low-energy spintronic memories. In this paper, we first analyze two different ME devices viz. ME-MTJ and ME-XNOR device with respect to writability, readability and switching speed. Our analysis is based on a coupled magnetization dynamics and electron transport model. Subsequently, we show that the decoupled read/write path of ME-MTJs can be utilized to construct an energy-efficient dual port memory. Further, we also propose a novel content addressable memory (CAM) exploiting the compact XNOR operation enabled by ME-XNOR device.

Published
2017

247. Technology Aware Training in Memristive Neuromorphic Systems based on non-ideal Synaptic Crossbars

Author

Chakraborty, Indranil, Roy, Deboleena, Roy, Kaushik, Chakraborty, Indranil, Roy, Deboleena, and Roy, Kaushik

Abstract

The advances in the field of machine learning using neuromorphic systems have paved the pathway for extensive research on possibilities of hardware implementations of neural networks. Various memristive technologies such as oxide-based devices, spintronics and phase change materials have been explored to implement the core functional units of neuromorphic systems, namely the synaptic network, and the neuronal functionality, in a fast and energy efficient manner. However, various non-idealities in the crossbar implementations of the synaptic arrays can significantly degrade performance of neural networks and hence, impose restrictions on feasible crossbar sizes. In this work, we build mathematical models of various non-idealities that occur in crossbar implementations such as source resistance, neuron resistance and chip-to-chip device variations and analyze their impact on the classification accuracy of a fully connected network (FCN) and convolutional neural network (CNN) trained with standard training algorithm. We show that a network trained under ideal conditions can suffer accuracy degradation as large as 59.84% for FCNs and 62.4% for CNNs when implemented on non-ideal crossbars for relevant non-ideality ranges. This severely constrains the sizes for crossbars. As a solution, we propose a technology aware training algorithm which incorporates the mathematical models of the non-idealities in the standard training algorithm. We demonstrate that our proposed methodology achieves significant recovery of testing accuracy within 1.9% of the ideal accuracy for FCNs and 1.5% for CNNs. We further show that our proposed training algorithm can potentially allow the use of significantly larger crossbar arrays of sizes 784$\times$500 for FCNs and 4096$\times$512 for CNNs with a minor or no trade-off in accuracy, Comment: 10 pages, 7 figures, submitted to IEEE Transactions on Emerging Topics in Computational Intelligence

Published
2017
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248. Mechanistic and energetic aspects of the thermal and photochemical redox chemistry of the octanuclear cubane complexes, [[Fe.sup.III].sub.8]([[mu].sup.4]-[O.sub.4])[([mu]-pyrazolate).sub.12][X.sub.4] (X = Cl or Br)

Author

Ferraudi, Guillermo, Piero, Dalice, Chakraborty, Indranil, Raptis, Raphael G., Lappin, A. Graham, and Berlin, Nicholas

Subjects
Iron -- Chemical properties, Organometallic compounds -- Chemical properties, Organometallic compounds -- Thermal properties, Oxidation-reduction reaction -- Analysis, Pyrazoles -- Chemical properties, Pyrazoles -- Thermal properties, Chemicals, plastics and rubber industries
Published
2010

250. Tuning of the [[[Cu.sub.3]([mu]-O)].sup.4+/5+] redox couple: spectroscopic evidence of charge delocalization in the mixed-valent [[[Cu.sub.3]([mu]-O)].sup.5+] species

Author

Rivera-Carrillo, Marlyn, Chakraborty, Indranil, Mezei, Gellert, Webster, Richard D., and Raptis, Raphael G.

Subjects
Copper -- Spectra, Copper -- Structure, Copper -- Chemical properties, Valence -- Research, Electron configuration -- Research, Chemistry
Abstract

Trinuclear [Cu.sup.II]-complexes are prepared and characterized and the effect of substitution of terminal ligands, as well as 4-R groups, in the one-electron oxidation process is examined by using cyclic voltammetry. The results have shown that the triangular, mixed-valent [[[Cu.sub.3]([mu]-O)].sup.5+] intermediate of pMMO catalytic activity might be characterized by its near infrared spectrum, provided it adopts the [super 1][A.sub.1] electronic structure.

Published
2008

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