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Robust Machine Learning Technique to Classify COVID-19 Using Fusion of Texture and Vesselness of X-Ray Images

Computer Modeling in engineering & sciences 2024年第2期138卷 1981-2004页

作者： Shaik Mahaboob Basha Victor Hugo Cde Albuquerque Samia Allaoua Chelloug Mohamed Abd Elaziz Shaik Hashmitha Mohisin Suhail Parvaze Pathan department of Electronics and Communication engineering N.B.K.R.Institute of Science&TechnologyVidyanagarAndhra Pradesh524413India department of Teleinformatics engineering Federal University of CearáFortaleza60455-970Brazil Information technology department College of Computer and Information SciencesPrincess Nourah bint Abdulrahman UniversityRiyadh84428Saudi Arabia department of Mathematics Faculty of ScienceZagazig UniversityZagazig44519Egypt Faculty of Computer science and engineering Galala UniversitySuez435611Egypt Artificial Intelligence Research Center(AIRC) College of Engineering and Information TechnologyAjman UniversityAjmanUnited Arab Emirates department of Electrical and Computer engineering Lebanese American UniversityByblos13-5053Lebanon department of Avionics Indian Institute of Space Science and TechnologyThiruvananthapuramKerala695547India department of Veterinary Clinical sciences University of MinnesotaSt.PaulMinnesota55108USA

Manual investigation of chest radiography(CXR)images by physicians is crucial for effective decision-making in COVID-19 ***,the high demand during the pandemic necessitates auxiliary help through image analysis and machine learning *** study presents a multi-threshold-based segmentation technique to probe high pixel intensity regions in CXR images of various pathologies,including normal *** information is extracted using gray co-occurrence matrix(GLCM)-based features,while vessel-like features are obtained using Frangi,Sato,and Meijering *** learning models employing Decision Tree(DT)and RandomForest(RF)approaches are designed to categorize CXR images into common lung infections,lung opacity(LO),COVID-19,and viral pneumonia(VP).The results demonstrate that the fusion of texture and vesselbased features provides an effective ML model for aiding *** ML model validation using performance measures,including an accuracy of approximately 91.8%with an RF-based classifier,supports the usefulness of the feature set and classifier model in categorizing the four different ***,the study investigates the importance of the devised features in identifying the underlying pathology and incorporates histogrambased *** analysis reveals varying natural pixel distributions in CXR images belonging to the normal,COVID-19,LO,and VP groups,motivating the incorporation of additional features such as mean,standard deviation,skewness,and percentile based on the filtered ***,the study achieves a considerable improvement in categorizing COVID-19 from LO,with a true positive rate of 97%,further substantiating the effectiveness of the methodology implemented.

关键词： Chest radiography(CXR)image COVID-19 classifier machine learning random forest texture analysis

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Review on film coolingofliquidrocketengines

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Propulsion and Power Research 2018年第1期7卷 1-18页

作者： S.R.Shine S.Shri Nidhi department of aerospace engineering Indian Institute of Space Science and TechnologyThiruvananthapuram 695547India

Film cooling in combination with regenerative cooling is presently considered as an efficient method to guarantee safe operation of liquid rocket engines having higher heat flux densities for long *** paper aims to bring all the research carried out in the field of liquid rocket engine film cooling since *** analytical and numerical procedure followed,experimental facilities and measurements made and major inferences drawn are reviewed in detail,and compared where ever *** has been made through a discussion of the analyses methodologies and the factors that influence film cooling *** effort has also been made to determine the status of the research,pointing out critical gaps,which are still to be explained and addressed by future generations.

关键词： Heat transfer Liquid rocketthrust chamber Film cooling Cooling effectiveness

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An accurate modeling of piezoelectric smart beams with first-order shear deformation theory

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International Journal of Modeling, Simulation, and Scientific Computing 2015年第2期6卷 179-197页

作者： Litesh N.Sulbhewar P.Raveendranath department of aerospace engineering indian institute of space science and technology thiruvananthapuram Kerala 695547India

A finite element model for piezoelectric smart beam in extension mode based on First-order Shear Deformation Theory(FSDT)with an appropriate through-thickness distribution of electric potential is *** of piezoelectric finite element formulations depends on the selection of assumed mechanical and electrical *** of the conventional FSDT-based piezoelectric beam formulations available in the literature use linear through-thickness distribution of electric potential which is actually ***,a novel quadratic profile of the through-thickness electric potential is proposed to include the nonlinear *** results obtained show that the accuracy of conventional formulations with linear through-thickness potential approximation is affected by the material configuration,especially when the piezoelectric material dominates the beam cross *** is shown that the present formulation gives the same level of accuracy for all regimes of material configurations in the beam cross ***,a modified form of the FSDT displacements is employed,which utilizes the shear angle as a degree of freedom instead of section *** a FSDT displacement field shows improved performance compared to the conventional *** present formulation is validated by comparing the results with ANSYS 2D *** comparison of results proves the improved efficiency and accuracy of the present formulation over the conventional formulations.

关键词： Actuator and sensor coupled field extension mode finite element piezoelectric smart beams variational formulation

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Numerical simulation of high speed reacting shear layers using AUSM+-up scheme-based unstructured finite volume method solver

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International Journal of Modeling, Simulation, and Scientific Computing 2017年第3期8卷 39-60页

作者： M.Deepu M.P.Dhrishit S Shyji department of aerospace engineering indian institute of space science and technology thiruvananthapuram KeralaIndia-695547 department of Mechanical engineering SCT College of engineering thiruvananthapuram KeralaIndia-695018

Development of an Advection Upstream Splitting Method(AUSM+-up)scheme-based Unstructured Finite Volume(UFVM)solver for the simulation of two-dimensional axisymmetric/planar high speed compressible turbulent reacting shear layers is *** inviscid numerical flux is evaluated using AUSM+-up upwind *** eight-step hydrogen–oxygen finite rate chemistry model is used to model the development of chemical species in a supersonic reacting flow *** chemical species terms are alone solved implicitly in this explicit flow solver by rescaling the equation in *** turbulence modeling has been done using RNG-based k–***-stage Runge–Kutta method has been used for explicit time *** nonreacting twodimensional Cartesian version of the same solver has been successfully validated against experimental and numerical results reported for the wall static pressure data in sonic slot injection to supersonic *** validation studies for reacting flow solver has been done using experimental results reported for a coaxial supersonic combustor,in which species profile at various axial locations has been *** numerical solver is useful in simulating combustors of high speed air-breathing propulsion devices.

关键词： Supersonic combustion turbulent reacting flows advection upstream splitting method

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Effects of multiple subcavities with floor subcavity in supersonic cavity flow

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Propulsion and Power Research 2023年第1期12卷 114-137页

作者： Priyansh Jain Anbarasan Sekar Aravind Vaidyanathan indian institute of space science and technology ThiruvananthapuramKerala 695547India

Experimental and computational analysis has been carried out by many researchers on supersonic cavity flow,but detailed analysis based on Rossiter’s model still requires some *** the current study an open rectangular cavity with a length to depth ratio of 2(L/D=2)and Mach number at the inlet as 1.71,was considered as a baseline configuration for experimental *** techniques such as power spectral density(PSD),correlation,and overall sound pressure level(OASPL)were carried out on the unsteady pressure data,to analyze the aero-acoustic flow ***-speed schlieren images were processed to obtain spatially coherent modes by proper orthogonal decomposition(POD).The analysis was extended for different dimensions of subcavities on the aft,floor,and front *** detailed analysis of these configurations with different dimensions and combinations revealed the various flow features and mode frequencies in supersonic *** the front wall subcavity act as a passive control device,reducing the overall sound pressure level inside the cavity whereas,the aft wall subcavity acts as a passive resonator with distinct harmonic fluidresonant modes,a similar phenomenon was observed for floor subcavity at different locations.A novel method was employed to analyze Rossiter’s model and its applicability in estimating experimental modes was verified,as it accurately predicted the dominant frequencies with a maximum of 2.74% uncertainty among all the configurations.

关键词： Supersonic cavity flow Fast Fourier transform High speed schlieren Proper orthogonal decomposition Rossiter’s feedback mechanism

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Effect of Pressure Level on the Performance of an Auto-Initiated Pulsed Plasma Thruster

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Plasma science and technology 2010年第4期12卷 466-472页

作者： Kelvin LOH Abhijit KUSHARI department of aerospace engineering Nanyang Technological University department of aerospace engineering Indian Institute of Technology

Pulsed plasma thrusters （PPT） are micro-propulsion devices used in satellites for station keeping. Conventionally the plasma discharge in a PPT is initiated by a spark plug. The primary objective of the present work was to develop and characterize a PPT that does not need a spark plug to initiate the plasma discharge. If the spark plug is eliminated, the size of the thrusters can be reduced and arrays of such thrusters can be manufactured using micro electro mechanical systems （MEMS） techniques, which can provide tremendous control authority over the satellite positioning. A parallel rail thruster was built and its performances were characterized inside a vacuum chamber to elucidate the effect of vacuum level on the performance. The electrical performance of the thruster was quantified by measuring the voltage output from a Rogowski coil, and the thrust produced by the developed thruster was estimated by measuring the force exerted by the plume on a light weight pendulum, whose deflection was measured using a laser displacement sensor. It was observed that the thruster can operate without a spark plug. In general, the performance parameters such as thrust, mass ablation, impulse bit, and specific impulse per discharge, would increase with the increase in pressure up to an optimum level due to the increase in discharge energy as well as the decrease in the total impedance of the plasma discharge. The thrust efficiency is found to be affected by the discharge energy.

关键词： plasma thruster auto-initiation solid propellant micro-thruster

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Regularized luni-solar gravity dynamics on resident space objects

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Astrodynamics 2021年第2期5卷 91-108页

作者： Harishkumar Sellamuthu Ram Krishan Sharma Agnikul Cosmos Private Limited Indian Institute of Technology MadrasChennai600036India department of aerospace engineering Karunya Institute of Technology and SciencesCoimbatore641114India

Resident space object population in highly elliptical high perigee altitude(>600 km)orbits is significantly affected by luni-solar *** regularization,an analytical orbit theory with luni-solar gravity effects as third-body perturbations in terms of Kustaanheimo-Stiefel regular elements is *** tests with different cases resulted in good accuracy for both short-and long-term orbit *** is observed that the luni-solar perturbations affect the accuracy of the analytical solution *** analytical theory is tested with the observed orbital parameters of the few objects in highly elliptical *** analytical evolution of osculating perigee altitude is found to be concurrent with observed *** perturbation,when compared with lunar perturbation,is established to be dominant over such orbits.

关键词： luni-solar perturbations regularization Kustaanheimo-Stiefel(KS)transformation

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Investigation of strong shock wave interactions with CeO2 ceramic

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Journal of Advanced Ceramics 2014年第4期3卷 297-305页

作者： Vishakantaiah JAYARAM Asha GUPTA K.P.J.REDDY Shock Induced Materials Chemistry Lab SSCUIndian Institute of ScienceBangalore-560012India Texas Materials institute the University of Texas at AustinAustinTexas 78712USA department of aerospace engineering Indian Institute of ScienceBangalore-560012India

Strong shock wave interactions with ceramic material ceria(CeO_(2))in presence of O_(2)and N2 gases were investigated using free piston driven shock tube(FPST).FPST is used to heat the test gas to very high temperature of about 6800-7700 K(estimated)at pressure of about 6.8-7.2 MPa for short duration(2-4 ms)behind the reflected shock *** is subjected to super heating and cooling at the rate of about 106 K/*** of CeO_(2)sample was done before and after exposure to shock heated test gases(O_(2)and N2).The surface composition,crystal structure,electronic structure and surface morphology of CeO_(2)ceramic were examined using X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD),Fourier transform infrared(FTIR)spectrometry,scanning electron microscopy(SEM)and high resolution transmission electron microscopy(HRTEM).Results obtained from the experimental investigations show that CeO_(2)can withstand high pressure accompanied by thermal shock without changing its crystal *** CeO_(2)releases lattice oxygen making it possible to shift between reduced and oxidized states upon the interaction with shock heated *** to such reaction mechanism,CeO_(2)ceramic undergoes nitrogen doping with decrease in lattice *** reveal that CeO_(2)retains its crystal structure during strong shock interaction,even at elevated pressure.

关键词： shock tube shock interaction high enthalpy gas ceria nitrogen-doped surface reaction

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Effects of Al addition and cryogenic cyclic treatment on impact toughness of phase-transformable Ti-based bulk metallic glass composites

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Journal of Materials science & technology 2023年第9期140卷 210-220页

作者： Tingyi Yan Long Zhang R.Lakshmi Narayan Jingyu Pang Yi Wu Huameng Fu Hong Li Upadrasta Ramamurty Haifeng Zhang Shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials science and engineering University of Science and Technology of ChinaShenyang 110016China CAS Key Laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China department of Materials science and engineering Indian Institute of Technology DelhiHauz KhasNew Delhi 110016India department of Mechanical and aerospace engineering in Nanyang Technological University Singapore 637331Singapore institute of Materials Research and engineering Agency for ScienceTechnology and Research(A∗STAR)Singapore 138634Singapore

Developing bulk metallic glass composites(BMGCs)with high toughness is vital for their practical ***,the influence of different microstructures on the impact toughness of BMGCs is still *** effects of Al addition and cryogenic cyclic treatment(CCT)on the Charpy impact toughness,a K,at 298 and 77 K of a series of phase-transformable BMGCs are investigated in this *** is found that deformation-induced martensitic transformation(DIMT)of theβ-Ti dendrites is the dominant toughening mechanism in the phase-transformable BMGCs at 298 K,but at 77 K,the toughness of BMGCs is primarily determined by the intrinsic toughness of the glass *** addition of Al can moderately tune theβ-Ti phase stability,which then affects the amount of DIMT and impact toughness of the BMGCs at 298 ***,at 77 K,Al addition causes a monotonic decrease in the toughness of the BMGCs due to the embrittlement of the glass *** is found that CCT can effectively rejuvenate the phase-transformable BMGCs,which results in an enhanced impact toughness at 298 ***,the toughness at 77 K monotonously decreases with increasing the number of CCT cycles,suggesting that the rejuvenation of the glass matrix affects the toughness at both 298 and 77 K of BMGCs,but in dramatically different *** findings reveal the influence of microstructures and CCT on the impact toughness of BMGCs and provide insights that could be useful for designing tougher BMGs and BMGCs.

关键词： Bulk metallic glass composites Charpy impact toughness Deformation-induced martensitic transformation Metastability Thermal cycling rejuvenation

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Nose-Tip Transition Control by Surface Roughness on a Hypersonic Sphere

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Journal of Flow Control, Measurement & Visualization 2018年第3期6卷 125-135页

作者： Kiran Joy Irimpan Viren Menezes K. Srinivasan Hamid Hosseini department of aerospace engineering Indian Institute of Technology Bombay Mumbai India Vikram Sarabhai space Centre Thiruvananthapuram India department of Bioelectrics Institute of Pulsed Power Science Kumamoto University Kumamoto Japan

The surface heat flux on a 100 mm diameter hypersonic sphere was reduced through surface roughness on its forebody. The test model was subjected to a hypersonic freestream of Mach 8.8 and Reynolds number 1.98 million/m, in a shock tunnel. Forebody surface heat transfer rates measured on smooth and rough spheres, under the same free-stream conditions, were compared. The comparison of heat flux indicated an overall reduction in surface heating rates on the rough model, which could be attributed to the delayed nose tip transition. The surface roughness on the forebody of the model generated miniature cavities. Stability of the free shear layer over the miniature cavities and entrapment of the destabilizing vortices in the cavities, make the flow over the rough test model more stable than the attached boundary layer over the smooth model, under transitional conditions.

关键词： Shock Tunnel Hypersonic Transition Surface Roughness Thermocouple

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