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In this paper, the natural supercavitys are studied both experimentally and numerically. A series of supercavitating vehicle water-entry test are carried out at different speeds, where it is found that the minimum pressure in the cavity gradually reduced with the increase of water-entry speed. The cause for the evolution progress of natural supercavitation is difficult to get from the experiment,...
In order to accurately control the portable AUV, a dynamic modeling method based on computational fluid dynamics (CFD) and a improved Generalized Predictive Control (GPC) method were presented. First, the whole modeling process was described from two aspects: dynamic model derivation and model parameter identification. Second, the validity of the model and modeling method were tested by comparing...
Simulation of unmanned underwater vehicles (UUVs) plays an important role in the development of submarine robots. The test of controllers in different simulated scenarios is crucial in order to avoid the lengthy development on the real vehicle. Robot simulators like Gazebo have been extensively used for this purpose, even if off-the-shelf physic engines do not consider one of the main aspects of hydrodynamics:...
In this study, virtual planar-motion-mechanism (PMM) tests in pure sway motion at constant forward speed are carried out to determine the sway added mass values of a 6:1 prolate spheroid. Added mass values are obtained by solving the Euler equations and the Reynolds Averaged Navier-Stokes (RANS) equations across a range of frequencies and depths. The effect that distance from the surface and radiation...
This study investigates near-shore circulation and wave characteristics applied to a case-study site in Monterey Bay, California. We integrate physics-based models to resolve wave conditions (based on inputs from a global wave model, wind data from an operational weather platform, and predictions from a regional flow model) together with a linear machine learning algorithm that combines forecasts...
A set of Matlab tools were developed to create seafloor mosaics from AUV photosurveys. The resulting mosaic products are used to guide instrument placement, ground-truth acoustic backscatter targets, and inspect sensor packages or other targets. Because of the positional sensitivity of these tasks, effort has been made to preserve the geographic distribution of the image content. After initial image...
Autonomous underwater vehicles (AUV) are important resources to be used in the oil exploration industry in deep waters as well as a platform for scanning devices used in open sea regions of difficult human access. This work aims to analyze through computer simulations the influence of marine currents on the maneuverability of a flatfish shaped AUV. The 3D realistic scale simulations were performed...
The National Tsunami Warning Center (NTWC) and the Pacific Tsunami Warning Center (PTWC) collaborate to provide tsunami warning service and mutual backup to tsunami-threatened areas throughout the United States and many other countries throughout the world. With mostly home-grown analysis systems, NTWC staff rapidly locates, sizes, and otherwise characterizes major earthquakes. We determine each earthquake's...
In order to analyze the dynamic performance of a Remotely Operated Vehicle (ROV) during mission like ship hull inspection, it is necessary to establish the 6 degree-of-freedom equations of motion considering well modeled hydrodynamic force acting on a ROV. Typically, the hydrodynamic force is the model by polynomial functions and those coefficients are obtained by captive model tests or empirical...
Collaborative filtering is widely used in recommender systems. When training data are extremely sparse, neighbor selection methods work ineffectively. To address this issue, this paper proposes a distributed representation model that represents users as low-dimensional vectors for neighbor selection by considering the chronological order of users' ratings. Experiments show that the proposed method...
Intelligent Transportation System (ITS) is integral towards envisioning a truly mobile and digital India. While existing solutions like smart vehicles and autonomous driving are inapplicable for Indian cities, transport surveys in India have provided offline solutions through GPS data. Without analytical formulations, they are prone to failure in ever-changing Indian urban landscape. This paper addresses...
Genome-wide association studies have discovered many biologically important associations of genes with phenotypes. Typically, genome-wide association analyses formally test the association of each genetic feature (SNP, CNV, etc) with the phenotype of interest and summarize the results with multiplicity-adjusted p-values. However, very small p-values only provide evidence against the null hypothesis...
Improvements in melanoma diagnosis, treatment and prognosis are urgently warranted, given that it causes 3 out of 4 skin cancer deaths. A large amount of genomic and molecular data indicate that alterations occur at multiple scales in different stages of melanoma. Metabolic rewiring is a characteristic feature of progressive cancers that facilitates sustenance of tumors, and caters to the changing...
Bidomain or monodomain model has frequently been used to study electrical activities in the cardiac tissue. The finite difference method with second order accuracy is commonly used to approximate the spatial derivatives of the governing equations numerically. In this work, a higher order finite difference scheme has been implemented to solve the nonlinear monodomain equation. The unknown transmembrane...
A new modeling approach and conceptual framework to the immune system response and its dual role with respect to cancer is proposed based on Applied Category Theory. States of cells and pathogenes are structured as mathematical structures (categories), the interactions, at a given phase, between cells of the immune system and pathogenes, correspond to a pair of adjunctions (adjoint functors), the...
An effective yellow fever vaccine has been available since 1937. However, some issues regarding its use remain open, such as the minimum dose that can provide immunity against the disease. Mathematical-computational tools can be useful to assist the search for answers to some of these open issues. In this context, this study presents a simplified mathematical-computational model of the human immune...
Over the past decades, numerous techniques have been developed to forecast the temporal evolution of epidemic outbreaks. This paper proposes an approach that combines high resolution agent-based models using realistic social contact networks for simulating epidemic evolution with a particle filter based method for assimilation based forecasting. Agent-based modeling using realistic social contact...
We consider the problem of causal structure learning from data with missing values, assumed to be drawn from a Gaussian copula model. First, we extend the 'Rank PC' algorithm, designed for Gaussian copula models with purely continuous data (so-called nonparanormal models), to incomplete data by applying rank correlation to pairwise complete observations and replacing the sample size with an effective...
With the rapid rise of various e-commerce and social network platforms, users are generating large amounts of heterogeneous behavior data, such as purchasehistory, adding-to-favorite, adding-to-cart and click activities, and this kind of user behavior data is usually binary, only reflecting a user's action or inaction (i.e., implicit feedback data). Tensor factorization is a promising means of modeling...
This paper considers the application of finite-time control to a Cucker-Smale flocking model of autonomous agents with collision avoidance. A mathematical expression for the upper bound on the flocking time is derived. Previous results without considering collision avoidance showed that the flocking time decreases as the number of robots in the flock increases, which is counter-intuitive. We showed...
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