A Block Matrix Based Precise Integration Algorithm for Solving Non-Homogeneous Dynamic Response

2021 ◽  
Author(s):  
Chao Zhang ◽  
Mingxiang Ling ◽  
Meng Tao
Keyword(s):  
Dynamic Response ◽  
Large Scale ◽  
Computing Time ◽  
Block Matrix ◽  
Computationally Efficient ◽  
Time Step ◽  
Integration Algorithm ◽  
Precise Integration ◽  
High Prediction ◽  
Cycle Oscillation

Abstract This paper puts forward a computationally-efficient parallel precise integration algorithm for solving vibration response subjected to time-variable excitation and nonlinearity, especially for non-homogenous dynamic response solution with large-scale degree of freedom. In detail, both of the nonlinear parts and time-varying inputs of the dynamic system are separated from the original dynamic equations and then simulated by employing a piecewise interpolation function within a computing time-step. A novel closed-form iteration formula is presented in conjunction with the block matrix strategy and modified increment-dimensional precise integration technique. Interestingly, the presented approach is essentially a high-accuracy and parallel algorithm, which exhibits a high prediction accuracy without the limitation of matrix inversion, higher-order derivative, periodicity requirement nor cycle oscillation and instability of high-order interpolation. At last, the feasibility and advantage of the proposed method is verified with two numerical examples.

A computationally efficient tool for assessing the depth resolution in large-scale potential-field inversion

Geophysics ◽  
2014 ◽  
Vol 79 (4) ◽  
pp. A33-A38 ◽  
Author(s):  
Valeria Paoletti ◽  
Per Christian Hansen ◽  
Mads Friis Hansen ◽  
Maurizio Fedi
Keyword(s):  
Potential Field ◽  
Large Scale ◽  
Computing Time ◽  
Depth Resolution ◽  
Source Distribution ◽  
Volcanic Area ◽  
Computationally Efficient ◽  
Large Scale Problems ◽  
Value Decomposition ◽  
Field Inversion

In potential-field inversion, careful management of singular value decomposition components is crucial for obtaining information about the source distribution with respect to depth. In principle, the depth-resolution plot provides a convenient visual tool for this analysis, but its computational complexity has hitherto prevented application to large-scale problems. To analyze depth resolution in such problems, we developed a variant ApproxDRP, which is based on an iterative algorithm and therefore suited for large-scale problems because we avoid matrix factorizations and the associated demands on memory and computing time. We used the ApproxDRP to study retrievable depth resolution in inversion of the gravity field of the Neapolitan Volcanic Area. Our main contribution is the combined use of the Lanczos bidiagonalization algorithm, established in the scientific computing community, and the depth-resolution plot defined in the geoscience community.

Flow Induced Vibration of Large Deflection Filament in Viscous Flow

2005 ◽  
Author(s):  
Cosmas P. Pagwiwoko ◽  
Tim David ◽  
Elijah Van Houten
Keyword(s):  
Dynamic Response ◽  
Boundary Conditions ◽  
Large Deflection ◽  
Stokes Equations ◽  
Density Ratio ◽  
Structural Response ◽  
Time Step ◽  
Integration Algorithm ◽  
Flowing Fluid ◽  
Fluid Structure

This work presents a numerical simulation of fluid-structure interaction of a highly flexible filament in a flow. A finite element model of nonlinear/large deflection cantilever beam is developed to represent the filament. The flow of Newtonian fluid is considered laminar and two-dimensional. The coupling of fluid-structure is carried out by using the fictitious domain algorithm where the moving boundary conditions are imposed. A no-slip condition is applied to all boundary conditions included on the surface of the moving filament. The structural response is calculated at one time step behind the solution of the Navier-Stokes equations. The additional mass plays an important role in dynamic response especially when the density ratio between the fluid and the filament becomes considerably high. To prevent the numerical instability, the equation of motion needs to be represented in a non-dimensional form by keeping the similarities of flow and dynamic response. A ramp function model is applied to simulate the gradual growth of fluid dynamic loads. In the structural part, a Crank-Nicholson integration algorithm is used in calculating the simultaneous structural response. The validation of the method was carried out through the existing experimental results for low density ratio of flowing fluid and filament material in wind-tunnel test, and for high density ratio in flowing soap test as well.

Cloud-Based Multimedia Content Protection System

2020 ◽  
pp. 164-169
Author(s):  
B. Aparna ◽  
S. Madhavi ◽  
G. Mounika ◽  
P. Avinash ◽  
S. Chakravarthi
Keyword(s):  
Large Scale ◽  
Protection System ◽  
Multimedia Content ◽  
Computationally Efficient ◽  
Content Protection ◽  
Protection Systems ◽  
Multimedia Content Protection ◽  
High Scalability ◽  
Cloud Infrastructures ◽  
Rapid Deployment

We propose a new design for large-scale multimedia content protection systems. Our design leverages cloud infrastructures to provide cost efficiency, rapid deployment, scalability, and elasticity to accommodate varying workloads. The proposed system can be used to protect different multimedia content types, including videos, images, audio clips, songs, and music clips. The system can be deployed on private and/or public clouds. Our system has two novel components: (i) method to create signatures of videos, and (ii) distributed matching engine for multimedia objects. The signature method creates robust and representative signatures of videos that capture the depth signals in these videos and it is computationally efficient to compute and compare as well as it requires small storage. The distributed matching engine achieves high scalability and it is designed to support different multimedia objects. We implemented the proposed system and deployed it on two clouds: Amazon cloud and our private cloud. Our experiments with more than 11,000 videos and 1 million images show the high accuracy and scalability of the proposed system. In addition, we compared our system to the protection system used by YouTube and our results show that the YouTube protection system fails to detect most copies of videos, while our system detects more than 98% of them.

scholarly journals GIANA allows computationally-efficient TCR clustering and multi-disease repertoire classification by isometric transformation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hongyi Zhang ◽  
Xiaowei Zhan ◽  
Bo Li
Keyword(s):  
T Cell ◽  
T Cell Receptor ◽  
Large Scale ◽  
Cell Receptor ◽  
Alignment Algorithm ◽  
Computationally Efficient ◽  
Antigen Specificity ◽  
Non Invasive ◽  
Isometric Transformation ◽  
Specific Receptors

AbstractSimilarity in T-cell receptor (TCR) sequences implies shared antigen specificity between receptors, and could be used to discover novel therapeutic targets. However, existing methods that cluster T-cell receptor sequences by similarity are computationally inefficient, making them impractical to use on the ever-expanding datasets of the immune repertoire. Here, we developed GIANA (Geometric Isometry-based TCR AligNment Algorithm) a computationally efficient tool for this task that provides the same level of clustering specificity as TCRdist at 600 times its speed, and without sacrificing accuracy. GIANA also allows the rapid query of large reference cohorts within minutes. Using GIANA to cluster large-scale TCR datasets provides candidate disease-specific receptors, and provides a new solution to repertoire classification. Querying unseen TCR-seq samples against an existing reference differentiates samples from patients across various cohorts associated with cancer, infectious and autoimmune disease. Our results demonstrate how GIANA could be used as the basis for a TCR-based non-invasive multi-disease diagnostic platform.

scholarly journals A Computationally Efficient Shallow Water Model for Mixed Cohesive and Non-Cohesive Sediment Transport in the Yangtze Estuary

Water ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1435
Author(s):  
Peng Hu ◽  
Junyu Tao ◽  
Aofei Ji ◽  
Wei Li ◽  
Zhiguo He
Keyword(s):  
Sediment Transport ◽  
Yangtze Estuary ◽  
Water Model ◽  
Cohesive Sediments ◽  
Shallow Water Model ◽  
Computationally Efficient ◽  
Time Step ◽  
The Yangtze Estuary ◽  
Erosion Coefficient ◽  
Cohesive Sediment Transport

In this paper, a computationally efficient shallow water model is developed for sediment transport in the Yangtze estuary by considering mixed cohesive and non-cohesive sediment transport. It is firstly shown that the model is capable of reproducing tidal-hydrodynamics in the estuarine region. Secondly, it is demonstrated that the observed temporal variation of suspended sediment concentration (SSC) for mixed cohesive and non-cohesive sediments can be well-captured by the model with calibrated parameters (i.e., critical shear stresses for erosion/deposition, erosion coefficient). Numerical comparative studies indicate that: (1) consideration of multiple sediment fraction (both cohesive and non-cohesive sediments) is important for accurate modeling of SSC in the Yangtze Estuary; (2) the critical shear stress and the erosion coefficient is shown to be site-dependent, for which intensive calibration may be required; and (3) the Deepwater Navigation Channel (DNC) project may lead to enhanced current velocity and thus reduced sediment deposition in the North Passage of the Yangtze Estuary. Finally, the implementation of the hybrid local time step/global maximum time step (LTS/GMaTS) (using LTS to update the hydro-sediment module but using GMaTS to update the morphodynamic module) can lead to a reduction of as high as 90% in the computational cost for the Yangtze Estuary. This advantage, along with its well-demonstrated quantitative accuracy, indicates that the present model should find wide applications in estuarine regions.

An Efficient Preconditioner for Linear System Solution in Multi-Domain Modeling of the Circulatory System

2013 ◽  
Author(s):  
Mahdi Esmaily Moghadam ◽  
Yuri Bazilevs ◽  
Tain-Yen Hsia ◽  
Alison Marsden
Keyword(s):  
Strong Coupling ◽  
Large Scale ◽  
Computational Cost ◽  
Circulatory System ◽  
Flow Simulation ◽  
Global Dynamics ◽  
Domain Modeling ◽  
Computationally Efficient ◽  
Lumped Parameter ◽  
System Solution

A closed-loop lumped parameter network (LPN) coupled to a 3D domain is a powerful tool that can be used to model the global dynamics of the circulatory system. Coupling a 0D LPN to a 3D CFD domain is a numerically challenging problem, often associated with instabilities, extra computational cost, and loss of modularity. A computationally efficient finite element framework has been recently proposed that achieves numerical stability without sacrificing modularity [1]. This type of coupling introduces new challenges in the linear algebraic equation solver (LS), producing an strong coupling between flow and pressure that leads to an ill-conditioned tangent matrix. In this paper we exploit this strong coupling to obtain a novel and efficient algorithm for the linear solver (LS). We illustrate the efficiency of this method on several large-scale cardiovascular blood flow simulation problems.

A Rapid Analysis Method for Microgyroscope Using System Vibration Modes

2009 ◽  
Vol 60-61 ◽  
pp. 353-356
Author(s):  
Guang Jun Liu ◽  
An Lin Wang ◽  
Zi Yi Yu ◽  
Xing Yang ◽  
Tao Jiang
Keyword(s):  
Performance Analysis ◽  
Dynamic Response ◽  
Computing Time ◽  
State Space Model ◽  
Rapid Analysis ◽  
Vibration Modes ◽  
Analysis Method ◽  
Space Model ◽  
System Equation ◽  
System Vibration

This paper proposes a rapid dynamic analysis method for microgyroscope using system vibration modes to solve the problems concerning to the computing time in the performance analysis of microgyroscope. The results of eigenvalue solution are employed to construct the state space model. The response of the microgyros cope can be reconstructed as a response superposition of the vibration modes, and then the system equation is decoupled into an uncoupled equation. The dynamic response of the microgyroscope can be calculated by a simple superposition.

A Low-Fidelity Stochastic Model of Viral Spread in Aircraft to Assess Risk Mitigation Strategies

2021 ◽  
Author(s):  
Leigh McCue
Keyword(s):  
Large Scale ◽  
Risk Mitigation ◽  
Mitigation Strategies ◽  
Traffic Network ◽  
Computationally Efficient ◽  
Passenger Compartment ◽  
Stochastic Effects ◽  
Viral Spread ◽  
Risk Mitigation Strategies ◽  
Baseline Health

Abstract The purpose of this work is to develop a computationally efficient model of viral spread that can be utilized to better understand influences of stochastic factors on a large-scale system - such as the air traffic network. A particle-based model of passengers and seats aboard a single-cabin 737-800 is developed for use as a demonstration of concept on tracking the propagation of a virus through the aircraft's passenger compartment over multiple flights. The model is sufficiently computationally efficient so as to be viable for Monte Carlo simulation to capture various stochastic effects, such as number of passengers, number of initially sick passengers, seating locations of passengers, and baseline health of each passenger. The computational tool is then exercised in demonstration for assessing risk mitigation of intervention strategies, such as passenger-driven cleaning of seating environments and elimination of middle seating.

A Fast and Scalable Heuristic for the Solution of Large-Scale Capacitated Vehicle Routing Problems

2021 ◽  
Author(s):  
Luca Accorsi ◽  
Daniele Vigo
Keyword(s):  
Vehicle Routing ◽  
Large Scale ◽  
Computing Time ◽  
Search Space ◽  
Iterated Local Search ◽  
Solution Quality ◽  
Routing Problem ◽  
Acceptance Criterion ◽  
Acceleration Techniques ◽  
Capacitated Vehicle

In this paper, we propose a fast and scalable, yet effective, metaheuristic called FILO to solve large-scale instances of the Capacitated Vehicle Routing Problem. Our approach consists of a main iterative part, based on the Iterated Local Search paradigm, which employs a carefully designed combination of existing acceleration techniques, as well as novel strategies to keep the optimization localized, controlled, and tailored to the current instance and solution. A Simulated Annealing-based neighbor acceptance criterion is used to obtain a continuous diversification, to ensure the exploration of different regions of the search space. Results on extensively studied benchmark instances from the literature, supported by a thorough analysis of the algorithm’s main components, show the effectiveness of the proposed design choices, making FILO highly competitive with existing state-of-the-art algorithms, both in terms of computing time and solution quality. Finally, guidelines for possible efficient implementations, algorithm source code, and a library of reusable components are open-sourced to allow reproduction of our results and promote further investigations.

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