Fast Yet Effective Machine Unlearning

Unlearning the data observed during the training of a machine learning (ML) model is an important task that can play a pivotal role in fortifying the privacy and security of ML-based applications. This paper raises the following questions: (i) can we unlearn a single or multiple classes of data from an ML model without looking at the full training data even once? (ii) can we make the process of unlearning fast and scalable to large datasets, and generalize it to different deep networks? We introduce a novel machine unlearning framework with error-maximizing noise generation and impair-repair based weight manipulation that offers an efficient solution to the above questions. An error-maximizing noise matrix is learned for the class to be unlearned using the original model. The noise matrix is used to manipulate the model weights to unlearn the targeted class of data. We introduce impair and repair steps for a controlled manipulation of the network weights. In the impair step, the noise matrix along with a very high learning rate is used to induce sharp unlearning in the model. Thereafter, the repair step is used to regain the overall performance. With very few update steps, we show excellent unlearning while substantially retaining the overall model accuracy. Unlearning multiple classes requires a similar number of update steps as for the single class, making our approach scalable to large problems. Our method is quite efficient in comparison to the existing methods, works for multi-class unlearning, doesn't put any constraints on the original optimization mechanism or network design, and works well in both small and large-scale vision tasks. This work is an important step towards fast and easy implementation of unlearning in deep networks. We will make the source code publicly available

Synthesis, crystal structure, redox property and theoretical studies of a pyrrole containing cobalt(III) Schiff base compound

A new mononuclear cobalt(III) complex with a pentadentate Schiff base ligand derived from the condensation of N-(3-aminopropyl)-propane-1,3-diamine with pyrrole-2-aldehyde has been synthesized and structurally characterized by X-ray crystallography. Structural analysis shows that the geometry of cobalt(III) ion is a distorted octahedron in which triamine part of the pentadentate ligand occupies the meridional positions, while two pyrrole nitrogen atoms are in cis disposition. Despite the potentially interesting similarities of pyrrole-based ligands to porphyrin systems, the present complex is inactive towards the oxidation of o-aminophenol, while analogous systems with pyridine containing ligands have proven to be efficient functional models for phenoxazinone synthase. Although the electrospray ionization mass spectral study clearly indicates the formation of a complex-substrate aggregate, the inability towards oxidation of o-aminophenol by the present complex can be explained electrochemically, where strong electron donating ability of the deprotonated pyrrole moiety reduces the possibility of reduction of cobalt(III) to cobalt(II).

Antioxidant attributes of tea in North Bengal, India: Relation with its principal constituents and properties of soil

This study was performed in 18 tea gardens in North Bengal, India, from 2012 to 2017. The data were pooled to investigate the relationship with soil physico-chemical properties, phyto-constituents, antioxidant attributes and age of the tea bushes and principal component analysis (PCA). PCA and dendro-hit maps were also performed with each region. The 28 principal components were chosen based on their eigen values, explaining the total data variance for tea in Dooars, Terai and Darjeeling hill. In almost all cases, composite soil physico-chemical attributes were heavily loaded on the second principal component and clustered, as visual evidenced by the dendro-hit map. Different attributes were significantly correlated each other in case of Terai i.e. (value of “r’’ at P<0.01 level) clay fraction (0.778), electrical conductivity (0.618), N (0.777), S (0.748), P (0.514 ppm), flavour index (0.918), total polyphenol (0.687) DPPH (0.794), nitric oxide (0.913), anti-lipid peroxidation (0.717) and metal chelating (0.665). In Dooars region, attributes were significantly correlated with silt (0.718), pH (0.875), P (0.615 ), chloride (0.858), TP (0.776), flavonol (0.923), quinone (0.666), tannins (0.865), DPPH (0.536), superoxide (0.576), ABTS (0.520) and MC (0.777) and in the case of Darjeeling hills, attributes were highly correlated with clay (0.812), sand (0.818), silt fraction (0.974), K (0.932), S (0.999), MC of soil (0.671), TP (0.853), tannins (0.912), DPPH (0.624), ABTS (0.661) and MC (0.633) repectively

TabSynDex: A Universal Metric for Robust Evaluation of Synthetic Tabular Data

Synthetic tabular data generation becomes crucial when real data is limited, expensive to collect, or simply cannot be used due to privacy concerns. However, producing good quality synthetic data is challenging. Several probabilistic, statistical, and generative adversarial networks (GANs) based approaches have been presented for synthetic tabular data generation. Once generated, evaluating the quality of the synthetic data is quite challenging. Some of the traditional metrics have been used in the literature but there is lack of a common, robust, and single metric. This makes it difficult to properly compare the effectiveness of different synthetic tabular data generation methods. In this paper we propose a new universal metric, TabSynDex, for robust evaluation of synthetic data. TabSynDex assesses the similarity of synthetic data with real data through different component scores which evaluate the characteristics that are desirable for "high quality" synthetic data. Being a single score metric, TabSynDex can also be used to observe and evaluate the training of neural network based approaches. This would help in obtaining insights that was not possible earlier. Further, we present several baseline models for comparative analysis of the proposed evaluation metric with existing generative models

Giant Magnetoimpedance (GMI) Effect and Field Sensitivity of Ferrofluid Coated Co66Fe2Si13B15Cr4 Soft Magnetic Amorphous Microwire

AbstractCo66Fe2Si13B15Cr4 based amorphous microwire was developed at the laboratory using in-water quenching apparatus. The field sensitivity of the wire was enhanced when coated with ferrofluids. The presence of coating also decreased the frequency of the magnetising field 5MHz to 1MHz at which the maximum GMI ratio observed

Optimization of DNA delivery by three classes of hybrid nanoparticle/DNA complexes

Plasmid DNA encoding a luciferase reporter gene was complexed with each of six different hybrid nanoparticles (NPs) synthesized from mixtures of poly (D, L-lactide-co-glycolide acid) (PLGA 50:50) and the cationic lipids DOTAP (1, 2-Dioleoyl-3-Trimethyammonium-Propane) or DC-Chol {3β-[N-(N', N'-Dimethylaminoethane)-carbamyl] Cholesterol}. Particles were 100-400 nm in diameter and the resulting complexes had DNA adsorbed on the surface (out), encapsulated (in), or DNA adsorbed and encapsulated (both). A luciferase reporter assay was used to quantify DNA expression in 293 cells for the uptake of six different NP/DNA complexes. Optimal DNA delivery occurred for 105 cells over a range of 500 ng - 10 μg of NPs containing 20-30 μg DNA per 1 mg of NPs. Uptake of DNA from NP/DNA complexes was found to be 500-600 times as efficient as unbound DNA. Regression analysis was performed and lines were drawn for DNA uptake over a four week interval. NP/DNA complexes with adsorbed NPs (out) showed a large initial uptake followed by a steep slope of DNA decline and large angle of declination; lines from uptake of adsorbed and encapsulated NPs (both) also exhibited a large initial uptake but was followed by a gradual slope of DNA decline and small angle of declination, indicating longer times of luciferase expression in 293 cells. NPs with encapsulated DNA only (in), gave an intermediate activity. The latter two effects were best seen with DOTAP-NPs while the former was best seen with DC-Chol-NPs. These results provide optimal conditions for using different hybrid NP/DNA complexes in vitro and in the future, will be tested in vivo

An unusual iminoacylation of 2-amino pyridyl thiazole: Synthesis, X-ray crystallography and DFT study of copper(II) amidine complexes and their cytotoxicity, DNA binding and cleavage study

Insertion of acetonitrile in the exocyclic NH2 group of the thiazole unit of 2-amino-4-(2-pyridyl)thiazole (HL) in the presence of copper chloride results in the formation of the monomeric amidine complex [Cu{LC(Me)double bondNH)}Cl2] (1). The same reaction of HL and copper(II) perchlorate yields the complex [Cu(HL)2](ClO4)2 (2), without acetonitrile insertion. However, the presence of a spacer donor, e.g. pyrazine, in the reaction medium results in the formation of a dinuclear amidine derivative, [(ClO4){LC(Me)double bondNH}Cu(μ-pyrazine)Cu{LC(Me)double bondNH}(ClO4)] (ClO4)2 (3). Complexes 1 and 3 are the first examples of copper assisted iminoacylation of 2-amino pyridylthiazole derivatives, confirming a nitrile to amidine transformation. The new complexes were characterized by single crystal X-ray crystallography, cyclic voltammetry and a DFT study. The complexes have a potential cytotoxic effect in human monocytic cells (U937) with IC50 values ranging from 0.84 to 4.5 μM. Significant necrotic activities are ascertained by a lactate dehydrogenase (LDH) enzyme release assay. The interaction with calf thymus (CT) DNA shows the binding constant (Kb) values are ∼104 M−1. The chemical nuclease activity of 1, 2 and 3 result in 65, 99 and 80% relaxation of supercoiled DNA at 10 μM in the presence of glutathione (GSH, 1 mM), respectively. The study with radical scavengers proved that a hydroxyl or singlet oxygen-like species is responsible for the DNA degradation.publishe

Biometric Pulse Counting System using Microcontroller 8051

ABSTRACT: This paper gives a novel idea about the design and implementation of a microcontroller based pulse counter. Intel 8051 is used as the main microcontroller unit and the system has been fabricated to count the total number of pulse in a minute. IR sensors are connected as the input sensors which read the blood flow through the fingers. The microcontroller counts the number of input signals and thus generates an output on a display window build using three 7 segment IC. This system is highly efficient, accurate and economical and thus can be effectively used as an instrument to measure pulse on medical grounds

Synthesis, characterization and antimicrobial activities of Co(III) and Ni(II) complexes with 5-methyl-3-formylpyrazole-N(4)-dihexylthiosemicarbazone (HMPzNHex2) : X-ray crystallography and DFT calculations of [Co(MPzNHex2)2]ClO4·1.5H2O (I) and [Ni(HMPzNHex2)2]Cl2·2H2O (II)

Manan Saha is thankful to the U.G.C., Govt. of India for providing financial support in the form of Rajiv Gandhi National Fellowship (Number and date of award letter: F1-17.1/2013-14/RGNF-2013-14-SC-WES- 51398/(SA-III/Website); 06/02/2014). N.C. Saha is thankful to the University of Kalyani for financial assistance received in the form of Personal Research Grant.A new pyrazole containing ligand, 5-methyl-3-formylpyrazole-N(4)-dihexylthiosemicarbazone (HMPzNHex2), and a host of its cobalt(III) and nickel(II) complexes, [Co(MPzNHex2)2]X·mH2O and [Ni(HMPzNHex2)2]X2·nH2O (X= Cl, Br, ClO4, BF4 and NO3; m = 0 for Cl, Br, BF4 & NO3 and 1.5 for ClO4; n = 0 for Br, ClO4, BF4 & NO3 and 2 for Cl), respectively, have been synthesized and characterized by elemental analyses, magnetic measurements (polycrystalline state), 1H NMR (for the ligand and its Co(III) complexes), electronic and IR spectral parameters. All the reported Co(III) and Ni(II) complexes are cationic in nature and behaving as 1:1 and 1:2 electrolytes, respectively, in MeOH. Electronic spectral data of the complexes categorize them as havingdistorted octahedral coordination geometry. IR spectral features (4000-/450 cm-1) specify a monodeprotonated / neutral tridentate (NNS) function of the ligand, HMPzNHex2 coordinating to the Co(III) / Ni(II) via the pyrazolyl (tertiary) ring nitrogen, azomethine nitrogen and thiolato / thioketo sulfur atom. 1H NMR spectral data (in CDCl3 at 400 MHz) for the primary ligand and those of its Co(III) complexes are in agreement with the proposition of bonding sites evidenced from IR data. The single crystal x-ray data of I (C2/c (#15); monoclinic) and II (P-1 (#2); triclinic) have confirmed a CoN4S2 and a NiN4S2 octahedral coordination, respectively. The pair of monoprotic / neutral coordinating ligands is more or less orthogonal to each other in the complex species. The data obtained from DFT calculations are reasonably in agreement with the UV-Vis spectral assignment and the structures of the complex species. Although the ligand and the tested metal ion complexes are capable of inhibiting microbial growth, the cobalt complexes can be promoted as better antimicrobial agents.PostprintPeer reviewe