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Differential fault location identification by machine learning

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CAAI Transactions on Intelligence Technology 2021年第1期6卷 17-24页

作者： Anubhab Baksi Santanu Sarkar Akhilesh Siddhanti Ravi Anand anupam chattopadhyay Nanyang Technological University Singapore Indian Institute of Technology ChennaiIndia Georgia Institute of Technology AtlantaUSA Indian Institute of Technology KharagpurIndia

As the fault‐based attacks are becoming a more pertinent threat in today's era of edge computing/internet‐of‐things,there is a need to streamline the existing tools for better accuracy and ease of use,so that we can gauge the attacker's power and a proper countermeasure can be devised in the long *** this regard,we propose a machine learning(ML)assisted tool that can be used in the context of a differential fault *** particular,finding the exact fault location by analysing the output difference(typically the XOR of the nonfaulty and the faulty ciphertexts)is somewhat *** the literature survey,we notice that the Pearson's correlation coefficient dominantly is used for this purpose,and has almost become the defacto *** this method can yield good accuracy for certain cases,we argue that an MLbased method is more powerful in all the situations we experiment *** sub-stantiate our claim by showing the relative performances(we choose the commonly used multilayer perceptron as our ML tool)with two variants of Grain‐128a(a stream cipher,and a stream cipher with authentication),the lightweight stream cipher LIZARD and the lightweight block cipher SIMON‐32(where the faults are injected at the fifth last rounds).Our results demonstrate that a common ML tool can outperform the correlation with the same training/testing *** believe that our work extends the state‐of‐the‐art by showing how traditional cryptographic methods can be replaced by a more powerful ML tool.

关键词： fault typically gauge

A novel formulation of material nonlinear analysis in structural mechanics

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Defence Technology（防务技术） 2021年第1期17卷 36-49页

作者： Himanshu Gaur anupam Srivastav Institute of Structural Mechanics Bauhause Universitat WeimarMarienstrasse 15D-99423WeimarGermany Department of Civil Engineering Middle East CollegeMuscatOman

This article demonstrates a novel approach for material nonlinear *** analysis procedure eliminates tedious and lengthy step by step incremental and then iterative procedure adopted classically and gives direct results in the linear as well as in nonlinear range of the material *** of elastic moduli is ***,stress and strain functions are used as the material input in the analysis *** stress and strain functions are directly derived from the stress-strain behavior of the material by the method of curve *** way,the whole stress-strain diagram is utilized in the analysis which naturally exposes the response of structure when loading is in nonlinear range of the material *** is found that it is an excellent computational procedure adopted so far for material nonlinear analysis which gives very accurate results,easy to adopt and simple in *** method eliminates all types of linearity assumptions in basic derivations of equations and hence,eliminates all types of possibility of errors in the analysis procedure as *** it is required to know stress distribution in the structural body by proper modelling and structural idealization,the proposed analysis approach can be regarded as stress-based analysis *** problems such as uniaxial problem,beam bending,and torsion problems are *** is found that approach is very suitable for solving the problems of fracture *** release rate for plate with center crack and double cantilever beam specimen is also *** approach solves the fracture problem with relative ease in strength of material style *** all problems,results are compared with the classical displacement-based liner theory.

关键词： Computational methods Material nonlinear analysis Fracture mechanics Energy release rate etc

A Review of Heat Transfer Enhancement through Flow Disruption in a Microchannel

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Journal of Thermal Science 2015年第3期24卷 203-214页

作者： anupam Dewan Pankaj Srivastava Department of Applied Mechanics Indian Institute of Technology Delhi Hauz Khas New Delhi - 110016 India Instruments R & D Establishment Defence R & D Organisation Dehradun (UK) - 248008 India

In this paper a comprehensive review of heat transfer enhancement through microchannels has been presented. Over the past few years due to multifunetion, shrinking package size and high power dissipation, the heat flux per unit area has increased significantly. Microchannels, with their large heat transfer surface to volume ratio and their small volumes, have shown a good thermal performance. Microchannels have been proven to be a high per- formaace cooling technique which is able to dissipate heat flux effectively from localized hot spots over small surface area. A good amount of heat transfer augmentation techniques have been reported on flow disruption through microchannel. These techniques promote free stream separation at the leading edge which results in boundary layer development and enhanced mixing leading to increased heat transfer. Flow disruption can be achieved through passive surface modifications, such as, shape of channel, dimple surfaces, ribs, cavities, groove structures, porous medium, etc. Combined effects of these geometrical configurations in heat transfer augmenta- tion are also reported in the literature. In this paper recent developments in experimental and numerical simula- tions of single-phase liquid cooled microchannel have been discussed to analyze the pressure drop, friction and heat transfer characteristics due to different flow conditions, roughness structure and passive surface modifica- tions. It has been observed that the flow disruption techniques are effective for heat transfer enhancement with lower penalties of increased pressure drop. The review concludes with suggestions for future research in this area.

关键词： Microchannel heat transfer enhancement boundary-layer pressure drop dimple surface cavitiesand ribs

Distribution of plant species along the elevation gradient in Pangi, a high altitude and remote eco-region in Western Himalaya, India

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Journal of Mountain Science 2024年第11期21卷 3739-3753页

作者： anupam BHATT Amit CHAWLA Department of Botanical and Environmental Sciences Guru Nanak Dev UniversityAmritsar 143005India Environmental Technology Division CSIR-Institute of Himalayan Bioresource TechnologyPalampur 176061India

The Himalayan high-altitude eco-regions exhibit higher plant species diversity, and several environmental factors play a crucial role in shaping species distribution and diversity. The aim of the present study is to investigate the floristic composition, distribution of endemic, threatened and native taxa across the elevation zones and the effect of various environmental factors on species richness pattern along the elevation gradient in Pangi, a remote highaltitude region of Himalaya. We conducted extensive field surveys covering 31 localities and established elevational transects for assessing species distribution and the factors affecting thereof. Additionally, information on nativity, endemism, and IUCN red-list categories of threatened species were compiled from published and online resources. Data were analysed using regression model and Non-Metric MultiDimensional Scaling(NMDS). In the present study, we recorded a total of 771 plant species across the region. In regression model, the elevation and anthropogenic variables and their interaction showed significant negative effects on the species richness. Species richness was found to decrease with the increasing elevation, showing a humped shaped pattern, with maximum richness observed in the mid-elevations(2,400m to 3,300m above sea level). The pattern of distribution of native and non-native species along the elevation gradient showed opposite trends, and proportion of native species increased towards the higher elevations. Further, NMDS ordination suggests that zone-Ⅰ(2,100-2,500m asl) and zone-Ⅴ(4,001-4,500m asl) had highest differences in species composition, while zone-Ⅰ, zone-Ⅱ(2,501-3,000m asl), and zone-Ⅲ(3,001-3,500m asl) showed higher affinity with respect to their species composition. Thus, the present study revealed that remote and hitherto un-explored Pangi eco-region is rich in floristic diversity and provides pertinent information on the species distribution and composition, and various underlyi

关键词： Elevational gradient Floristic Himalaya IUCN Native Richness pattern

Improved properties and thermal stability of a titanium-stainless steel solid-state weld with a niobium interlayer

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Journal of Materials Science & Technology 2021年第20期79卷 191-204页

作者： Jianxiong Li anupam Vivek Glenn Daehn Department of Materials Science and Engineering The Ohio State University2041 College RoadColumbusOH43210USA

Stainless steel(SS)and titanium alloys can be welded in the solid-state by high speed oblique ***,the effect of a niobium(Nb)interlayer on weld strength and thermal stability is *** Ti/SS and Ti/Nb/SS welds were subjected to thermal exposure ranging from 300℃ to 950℃ for 1.5 *** exposure monotonically decreases the strength and toughness of the Ti/SS pair with a dramatic falloff in strength and change in failure mode from partial pullout failure to full interfacial fracture at 600℃.With the interlayer,toughness was increased versus baseline up to 700℃ thermal exposure and then intermetallic formation again caused falloff in *** for the production,properties and applications of these classes of welds are provided.

关键词： Impact spot welding Titanium alloy Stainless steel Nb interlayer Thermal exposure Phase transformation

Shock effects on the upper limit of the collision weld process window

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Advances in Manufacturing 2024年第2期12卷 365-378页

作者： Blake Barnett anupam Vivek Glenn Daehn Department of Materials Science and Engineering The Ohio State UniversityColumbusOH43210USA Army Research Directorate Army Research LaboratoryDEVCOMAberdeen Proving GroundHarfordMD21005USA

The maximum flyer impact velocity based on a dynamic solidification cracking mechanism is proposed to describe the upper limit of collision welding process ***,the upper limit of the weld window is governed by the evolution of dynamic stresses and temperatures at the weld *** formulations for the upper limit of the collision weld window assume that both the flyer and target are made of the same material and approximate stress propagation velocities using the acoustic velocity or the shear wave velocity of the weld ***,collision welding fundamentally depends on the impacts that generate shockwaves in weld members,which can dominate the stress propagation velocities in thin weld ***,this study proposes an alternative weld window upper limit that approximates stress propagation using shock velocities calculated from modified 1-D Rankine-Hugoniot *** shock upper limit is validated against the experimental and simulation data in the collision welding literature,and offers a design tool to rapidly predict more accurate optimal collision weld process limits for similar and dissimilar weld couples compared to existing models without the cost or complexity of high-fidelity simulations.

关键词： Collision welding Solid-state welding Shock impact Weld process modelling Explosive bonding Laser impulse welding(LIW)

Impact of a Magnetic Dipole on Heat Transfer in Non-Conducting Magnetic Fluid Flow over a Stretching Cylinder

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Fluid Dynamics & Materials Processing 2024年第3期20卷 475-486页

作者： anupam Bhandari Department of Mathematics School of EngineeringUniversity of Petroleum&Energy Studies(UPES)Energy Acres BuildingBidholi DehradunUttarakhand248007India

The thermal behavior of an electrically non-conducting magnetic liquid flowing over a stretching cylinder under the influence of a magnetic dipole is *** governing nonlinear differential equations are solved numerically using a finite element approach,which is properly validated through comparison with earlier results available in the *** results for the velocity and temperature fields are provided for different values of the Reynolds number,ferromagnetic response number,Prandtl number,and viscous dissipation *** influence of some physical parameters on skin friction and heat transfer on the walls of the cylinder is also *** applicability of this research to heat control in electronic devices is discussed to a certain extent.

关键词： Ferrofluid stretching cylinder finite element method heat transfer magnetic dipole

Radiation and Chemical Reaction Effects on Nanofluid Flow Over a Stretching Sheet

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Fluid Dynamics & Materials Processing 2019年第5期15卷 557-582页

作者： anupam Bhandari University of Petroleum&Energy Studies(UPES) Department of MathematicsSchool of EngineeringEnergy Acres BuildingBidholi Dehradun248007UttarakhandIndia

The present research aims to examine the steady state of the two-dimensional incompressible magnetohydrodynamics(MHD)flow of a micropolar nanofluid over a stretching sheet in the presence of chemical reactions,radiation and viscous *** effect of particle rotation is taken into account.A conducting fluid passes over a semi-infinite plate with variable temperature while a magnetic field is directed in the transverse *** for velocity,angular momentum,temperature and concentration profiles are obtained for various values of Eckert number,Schmidt number,Prandtl number,thermophosis parameter and Brownian motion parameters.A similarity approach is used to transform the original set of two-dimensional partial differential equations into a set of highly nonlinear-coupled differential equations in dimensionless form.A numerical solution is obtained with the help of the COMSOL multiphysics software in the framework of a finite element *** findings indicate that on increasing Brownian motion and the chemical reaction rate,the fluid temperature becomes *** increase in the values of other physical parameters has the opposite effect.A variation in the boundary layer thickness typically results in changes in the concentration distribution in the *** angular velocity is deeply affected by the Eckert number,material parameter and magnetic number.

关键词： Nanofluid magnetohydrodynamics rotation temperature concentration

AN INVESTIGATION OF TURBULENT RECTANGULAR JET DISCHARGED INTO A NARROW CHANNEL WEAK CROSSFLOW

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Journal of Hydrodynamics 2008年第2期20卷 154-163页

作者： PATHAK Manabendra DASS Anoop K. DEWAN anupam Department of Mechanical Engineering Indian Institute of Technology Guwahati Guwahati - 781039 India

A computational investigation of the mean flow field of turbulent rectangular jets issuing into a narrow channel crossflow is presented. The length of the jet slot spans more than 55% of the crossflow channel bed, leaving a small clearance between the jet edge and sidewalls. A finite volume code employing the standard k-εmodel is used to predict the mean, three-dimensional flow field. The mean flow field is investigated for two velocity ratios （6 and 9）. Important flow features, such as the formation of different vortical structures and their characteristics owing to different values of the velocity ratio, are discussed. Some predicted results are compared with the experimental data reported in the literature. The predicted mean and turbulent flow properties are shown to be in good agreement with the experimental data.

关键词： turbulent jet crossflow narrow charmel velocity ratio vortices