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An SPH Framework for Earthquake-Induced Liquefaction Hazard Assessment of Geotechnical Structures

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Computer Modeling in Engineering & Sciences 2025年第1期142卷 251-277页

作者： sourabh Mhaski G.V.Ramana Department of Civil Engineering Indian Institute of Technology DelhiNew Delhi110016India

Earthquake-induced soil liquefaction poses significant risks to the stability of geotechnical structures *** understanding of the liquefaction triggering,and the post-failure large deformation behaviour is essential for designing resilient *** present study develops a Smoothed Particle Hydrodynamics(SPH)framework for earthquake-induced liquefaction hazard assessment of geotechnical *** coupled flowdeformation behaviour of soils subjected to cyclic loading is described using the PM4Sand model implemented in a three-phase,single-layer SPH framework.A staggered discretisation scheme based on the stress particle SPH approach is adopted to minimise numerical inaccuracies caused by zero-energy modes and tensile ***,non-reflecting boundary conditions for seismic analysis of semi-infinite soil domains using the SPH method are *** numerical framework is employed for the analysis of cyclic direct simple shear test,seismic analysis of a level ground site,and liquefaction-induced failure of the Lower San Fernando *** agreement for liquefaction triggering and post-failure behaviour demonstrates that the SPH framework can be utilised to assess the effect of seismic loading on field-scale geotechnical *** present study also serves as the basis for future advancements of the SPH method for applications related to earthquake geotechnical engineering.

关键词： Earthquake seismic liquefaction stress particle PM4Sand smoothed particle hydrodynamics(SPH)

Segmentation and classification of high spatial resolution images based on Hölder exponents and variance

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Geo-Spatial Information Science 2017年第1期20卷 39-45页

作者： Debasish Chakraborty sourabh Singh Dibyendu Dutta Regional Remote Sensing Centre-East National Remote Sensing CentreISRONew TownKolkataIndia Department of Computer Science and Engineering SMITSikkimIndia

Pixel-based or texture-based classification technique individually does not yield an appropriate result in classifying the high spatial resolution remote sensing imagery since it comprises textured and non-textured *** this study,Hölder exponents(HE)and variance(VAR)are used together to transform the image for measuring texture.A threshold is derived to segment the transformed image into textured and non-textured ***,the original image is extracted into textured and non-textured regions using this segmented image ***,extracted textured region is classified using ISODATA classification algorithm considering HE,VAR,and intensity values of individual pixel of textured *** extracted non-textured region of the image is classified using ISODATA classification *** case of non-textured region,HE and VAR value of individual pixel is not considered for classification for significant textural variation is not found among different ***,the classified outputs of non-textured and textured regions that are generated independently are merged together to get the final classified *** 1 m PAN images are classified using the proposed algorithm,and the classification accuracy is more than 88%.

关键词： High-resolution image texture segmentation Hölder exponents variance contrast classification ISODATA

Quantum dot lasers and integrated optoelectronics on silicon platform Invited Paper

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Chinese Optics Letters 2008年第10期6卷 727-731页

作者： Pallab bhattacharya Department of Electrical Engineering and Computer Science University of MichiganAnn ArborMI 48015USA

Chip-scale integration of optoelectronic devices such as lasers, waveguides, and modulators on silicon is prevailing as a promising approach to realize future ultrahigh speed optical interconnects. We review recent progress of the direct epitaxy and fabrication of quantum dot （QD） lasers and integrated guided-wave devices on silicon. This approach involves the development of molecular beam epitaxial growth of self- organized QD lasers directly on silicon substrates and their monolithic integration with amorphous silicon waveguides and quantum well electroabsorption modulators. Additionally, we report a preliminary study of long-wavelength （〉 1.3 μm） QD lasers grown on silicon and integrated crystalline silicon waveguides using membrane transfer technology.

关键词： GaAs InAs Quantum dot lasers and integrated optoelectronics on silicon platform Invited Paper QDs

Prediction of Bandwidth of Metamaterial Antenna Using Pearson Kernel-Based Techniques

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Computers, Materials & Continua 2024年第3期78卷 3449-3467页

作者： Sherly Alphonse S.Abinaya sourabh Paul School of Computer Science and Engineering Vellore Institute of TechnologyChennai600127India School of Electronics Engineering Vellore Institute of TechnologyChennai600127India

The use of metamaterial enhances the performance of a specific class of antennas known as metamaterial *** radiation cost and quality factor of the antenna are influenced by the size of the *** antennas allow for the circumvention of the bandwidth restriction for small *** parameters have recently been predicted using machine learning algorithms in existing *** learning can take the place of the manual process of experimenting to find the ideal simulated antenna *** accuracy of the prediction will be primarily dependent on the model that is *** this paper,a novel method for forecasting the bandwidth of the metamaterial antenna is proposed,based on using the Pearson Kernel as a standard *** with these new approaches,this paper suggests a unique hypersphere-based normalization to normalize the values of the dataset attributes and a dimensionality reduction method based on the Pearson kernel to reduce the dimension.A novel algorithm for optimizing the parameters of Convolutional Neural Network(CNN)based on improved Bat Algorithm-based Optimization with Pearson Mutation(BAO-PM)is also presented in this *** prediction results of the proposed work are better when compared to the existing models in the literature.

关键词： Antenna pearson optimization bandwidth metamaterial

Lithofacies architecture and palaeogeography of the Late Paleozoic glaciomarine Talchir Formation,Raniganj Basin,India

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Journal of Palaeogeography 2015年第3期4卷 269-283页

作者： H.N.bhattacharya Biplab bhattacharya Department of Geology Presidency University Department of Earth Sciences Indian Institute of Technology

Talchir Formation （Permo-Carboniferous） of the Gondwana Supergroup records the Late Paleozoic glaciation in Peninsular India. Talchir sedimentary succession of the Raniganj Basin, Damodar Valley Coalfields, Peninsular India, bears ten facies types grouped under three facies associations, viz., the proglacial conglomerate-sandstone facies association （CS）, the foreshore-shoreface conglomerate-sandstone-mudstone facies association （CSM） and the prodelta-shelf sandstone-mudstone facies association （SM）. Overall facies architecture reflects initial ice-covered terrestrial subgiacial sedimentation, which was subsequently reworked and emplaced subaqueously in front of the ice-grounding line, and finally overlapped by storm-laid prodelta-shelf sediments. Repeated glacial advance-retreats with shifts in the position of the ice-grounding line during phases of climatic amelioration led to multiple deglaciation-related fining-up cycles. Decoupled ice sheet and floating icebergs contributed icerafted debris （IRD） to these sediments. Gradual retreat of the ice sheet, however, restricted the supply of IRD towards top of the succession. Overlap of wave-agitated shoreface-shelf sediments on the glaciogenic sediments indicates widespread marine transgression caused by glacier melting during ice-house to green-house climatic transition, and crustal downsagging related to giacioisostasy. Subsequently, complete disappearance of the ice sheet caused basinal exhumation along with crustal uplift due to isostatic rebound, leading to multiple horst-graben bounded basinal systems, which received post-Talchir coal-bearing Gondwana sediments.

关键词： Late Pateozoic Tatchir Formation Ranganj Basin giaciornarine sedimen-tation facies architecture sequence stratigraphy

Modelling and control of a spatial dynamic cable

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Acta Mechanica Sinica 2019年第4期35卷 866-878页

作者： Bo Tian Subhrajit bhattacharya Department of Mechanical Engineering and Mechanics Lehigh University Bethlehem PA 18015 USA

We study the problem of dynamically controlling the shape of a cable that is fixed at one end and attached to an actuated robot at another end. This problem is relevant to unmanned aerial vehicles (UAVs) tethered to a base. While rotorcrafts, such as quadcopters, are agile and versatile in their applications and have been widely used in scientific, industrial and military applications, one of the biggest challenges with such UAVs is their limited battery life that make the flight time for a typical UAVs limited to twenty to thirty minutes for most practical purposes. A solution to this problem lies in the use of cables that tether the UAV to a power outlet for constant power supply. However, the cable needs to be controlled effectively in order to avoid obstacles or other UAVs. In this paper, we develop methods for controlling the shape of a cable using actuation at one end. We propose a discrete model for the spatial cable and derive the equations governing the cable dynamics for both force controlled system and position controlled system. We design a controller to control the shape of the cable to attain the desired shape and perform simulations under different conditions. Finally, we propose a quasi-static model for the spatial cable and discuss the stability of this system and the proposed controller.

关键词： Lagrangian mechanics Discrete model of cable Control of under-actuated systems

Plant-derived natural compounds in the treatment of arsenic-induced toxicity

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Asian Pacific Journal of Tropical Biomedicine 2023年第9期13卷 369-377页

作者： Sanjib bhattacharya West Bengal Medical Services Corporation Ltd. GN-29Sector VSalt Lake CityKolkata 700091West BengalIndia

Arsenic toxicity,imposed mainly by arsenic-contaminated groundwater,is considered a critical threat to global communal health,as there is no specific and proven conventional therapy for chronic arsenic toxicity,i.e.,arsenicosis,which is an insidious global public health menace affecting 50 *** options should,therefore,be explored for the mitigation of *** survey reveals several natural compounds from plants possess significant protective efficacy against arsenic toxicity in chiefly preclinical and few clinical *** studies on the ameliorative effects of plant-derived natural compounds against arsenic toxicity published in the last 25 years are ***-eight plant-based natural compounds possess alleviative effects on experimental arsenic-induced toxicity in animals,six of which have been reported to be clinically effective in humans.A potential nutraceutical or therapeutic candidate against arsenicosis for humans may thus be developed with the help of recent advancements in research in this area,along with the currently available treatments.

关键词： Arsenic toxicity Arsenicosis Natural compounds Vitamins

Code Based Analysis for Object-Oriented Systems

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Journal of Computer Science & Technology 2006年第6期21卷 965-972页

作者： Swapan bhattacharya Ananya Kanjilal Department of Computer Science and Engineering Jadavpur University Kolkata-700032 India Department of Information Technology B. P. Poddar Institute of Management and Technology Kolkata-700052 India

Tile basic features of object-oriented software makes it difficult to apply traditional testing methods in objectoriented systems. Control Flow Graph （CFG） is a well-known model used for identification of independent paths in procedural software. This paper highlights the problem of constructing CFG in object-oriented systems and proposes a new model named Extended Control Flow Graph （ECFG） for code based analysis of Object-Oriented （OO） software. ECFG is a layered CFG where nodes refer to methods rather than statements. A new metrics Extended Cyclomatic Complexity （E-CC） is developed which is analogous to McCabe＇s Cyclomatic Complexity （CC） and refers to the number of independent execution paths within the OO software. The different ways in which CFG＇s of individual methods are connected in an ECFG are presented and formulas for E-CC for these different cases are proposed. Finally we have considered an example in Java and based on its ECFG, applied these cases to arrive at the E-CC of the total system as well as proposed a methodology for calculating the basis set, i.e., the set of independent paths for the OO system that will help in creation of test cases for code testing.

关键词： object-oriented testing extended control flow graph extended cyclomatic complexity test paths graph-based testing

Marinoan glaciation in the Indian subcontinent——Anatomy and global implications

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Journal of Palaeogeography 2024年第2期13卷 293-308页

作者： H.N.bhattacharya Department of Earth Sciences Techno India UniversityWest BengalSector VSalt LakeKolkata700091India

Detailed sedimentological analysis of the Pokaran Boulder Bed,representing the most basal unit of the Neoproterozoic-Lower Cambrian Marwar Supergroup,clearly indicates its glacial *** glacial sediments are interpreted as an ice-contact submarine fan *** on the detrital and inherited zircon population of the Marwar Supergroup sediments and interlayered pyroclastic deposits,a Marinoan cryochron of the Cryogenian Period is envisaged for the Pokaran Boulder *** well-preserved Ediacaran elements in the post-glacial sedimentary succession also support a Cryogenian to Early Cambrian age of the Marwar *** glacial deposition at the base of the Marwar Supergroup strengthens the regional correlation between the studied sediments with the Lesser Himalayan Blaini-Krol-Tal sediments and the Haqf Supergroup of *** available zircon ages and paleomagnetic data of the Malani Igneous suite,along with the Marinoan glacial deposits,detrital zircon ages,and Ediacaran fossil elements of the Marwar Supergroup add significant information to the Neoproterozoic Earth history.

关键词： Neoproterozoic Marinoan glaciation Diamictites Pokaran Boulder Bed Marwar Supergroup