The authors' survey paper is devoted to the present state of computational methods in linear algebra. Questions discussed are the means and methods of estimating the quality of numerical solution of computational ...
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Modern industrial systems are real time controlled and supervised by means of automatic computer-based control systems, combining discrete and continuous behaviors, and are best modeled as hybrid systems (HS). In this...
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ISBN:
(纸本)9781479977871
Modern industrial systems are real time controlled and supervised by means of automatic computer-based control systems, combining discrete and continuous behaviors, and are best modeled as hybrid systems (HS). In this paper, two methods for the verification of the diagnosability of hybrid systems are proposed. The first method is based on the construction of a diagnoser automaton, that can also be straightforwardly used for online diagnosis, and the second method is based on a verifier automaton that, although cannot be used for online diagnosis, can be constructed in polynomial time, leading to a smaller computational complexity for the verification of the diagnosability of HS than the method using diagnoser automata. The main idea of the second method is to build a verifier of the underlying discrete-event system (DES), taking into account the distinguishability of the system modes based on the continuous state models of the HS.
The main purpose of this paper is to present computational methods for simulating some typical problems in the emerging computational geoscience field. Due to remarkable differences between engineering systems and Ear...
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The main purpose of this paper is to present computational methods for simulating some typical problems in the emerging computational geoscience field. Due to remarkable differences between engineering systems and Earth ones, existing computational methods, which are designed for solving engineering problems, cannot be directly used to solve geoscience problems without any modification. However, the fundamental philosophy of developing computational methods is applicable to the computational simulation of both geoscience and engineering problems. Because of their inherent approximation, computational methods must be verified before putting into application. After several computational methods and algorithms, which are developed for simulating some typical problems in the emerging computational geoscience field, are briefly introduced, a typical geoscience problem, known as the chemical dissolution-front instability problem in ore-forming systems of supercritical Zhao numbers, is selected to demonstrate how computational methods can be used to solve geoscience problems.
Assessment of vascularity of conjunctiva has many diagnostic and prognostic applications, thus creation of computational methods for its fast and objective assessment is of importance. Here we provide two different me...
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ISBN:
(纸本)9781457717871
Assessment of vascularity of conjunctiva has many diagnostic and prognostic applications, thus creation of computational methods for its fast and objective assessment is of importance. Here we provide two different methods for estimation of conjunctiva's vascularity from color digital images, with our best results showing a correlation coefficient of 0.89 between the predicted and ground truth values using a committee of artificial neural networks.
This paper examines the pressure field effects of the interaction between an operating nacelle mounted turbofan engine and a wing. We perform this study through the variation of location of an effective blockage volum...
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ISBN:
(数字)9781624105951
ISBN:
(纸本)9781624105951
This paper examines the pressure field effects of the interaction between an operating nacelle mounted turbofan engine and a wing. We perform this study through the variation of location of an effective blockage volume representing the running engine/nacelle. We examine the effect that an engine's presence has on the local pressure distribution on the upper and lower surfaces of a wing. We determine the effects on total system lift, minimum pressure coefficient (-Cp), and critical sonic Mach number (Mcr). We study three major factors for placement: 1) the vertical location above and below the wing, 2) the chord-wise location of blockage, and 3) the diameter of effective blockage. The engine-wing-body aerodynamics effects are modeled using a potential flow CFD code. It was found that areas of positive pressure existed both fore and aft of the engine, while negative pressure was present surrounding the body. The closer the body was to the wing, the stronger the effects were on the surfaces. The key metrics relating to the utility of transonic lift, Cpmin, and Mcr were significantly affected by the engine blockage. The engine-wing interference effects were determined to be significant and critically important to an air vehicle design. Wings should be designed in the presence of nacelles operating at realistic mass flow conditions.
In recent years, increasing ship-sizes and associated increasing wave loads have led to a demand for prediction tools quantifying the ship-induced loads on waterways. Depth-averaged numerical models, using a free surf...
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ISBN:
(纸本)9780791885925
In recent years, increasing ship-sizes and associated increasing wave loads have led to a demand for prediction tools quantifying the ship-induced loads on waterways. Depth-averaged numerical models, using a free surface pressure term, are a prominent method to obtain the relevant design parameters. These models incorporate the wave deformation processes due to attributes of complex bathymetries, while allowing for an efficient simulation of large computational domains. The non-hydrostatic shallow water equations model REEF3D::SFLOW uses a quadratic pressure approximation and high-order discretisation schemes. This paper presents the implementation of a pressure term to account for the displacement of the free surface by solid moving objects. Two test cases verifying the implementation are shown based upon the analytical 1-dimensional solution of the wave propagation due to surface pressure and the estimation of Havelock angles. These verification tests are the first step towards a holistic model, combining a large scale model with CFD simulations near waterway banks.
Social contact networks play an increasingly important role in computational epidemiology. We focus on massive social contact networks that cover an urban region comprising of millions of individuals and billions of t...
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ISBN:
(纸本)9781479948970
Social contact networks play an increasingly important role in computational epidemiology. We focus on massive social contact networks that cover an urban region comprising of millions of individuals and billions of time varying interactions. It is impossible to obtain such networks by simply measuring social interactions. As a result, such networks are often synthesized using a diverse set of real-world data. The synthesis method can be viewed as a complex stochastic process that outputs one realization of such a network. The resulting networks are extremely large, dynamic and unstructured. Any meaningful description of such networks is usually done in terms of structural properties. Building on our earlier work, we synthesize a detailed social contact network for the National Capital Territory (NCT) of India. We first synthesize a social visitation network, representing people visiting locations during different time intervals. We then project it to synthesize a people-people contact network. We are not aware of other works on synthesizing the NCT network. Two important questions arise when synthesizing such massive dynamic social contact networks: (i) how does one compare the networks that span the same region and (ii) when is the synthesized network adequate. To address them, we compute a number of network measurements: some of which are classical;while others capture the semantics of social contact networks. These metrics are used to study the similarities and differences between two networks representing the same urban region. For question (ii), we study our ability to understand the dynamics and control of epidemics. Dynamical measures that capture the joint interaction between the local dynamical process and the network structure are presented and used to analyze the NCT networks.
Resting-state functional magnetic resonance imaging (rsfMRI) is a non-invasive method to study brain function and organization. The last decades have seen a dramatic growth of human rsfMRI studies, public datasets, an...
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Resting-state functional magnetic resonance imaging (rsfMRI) is a non-invasive method to study brain function and organization. The last decades have seen a dramatic growth of human rsfMRI studies, public datasets, and data analysis software, which advanced our understanding of neuroscience and brain diseases. However, studies and resources of rodent rsfMRI are still lacking, despite its essential role in translational research. In this dissertation, we first present an open database of rsfMRI data collected from 90 awake rats with a well-established awake imaging paradigm that avoids anesthesia interference, together with a preprocessing pipeline optimized for rat data. Based on this dataset, we propose two methods termed SHERM and fastClean towards automated preprocessing of rodent rsfMRI data. First, SHERM targets rodent brain extraction, which is an essential step to aid with rsfMRI image registration. Current methods usually require manual adjustment of input parameters due to widely different image qualities and/or contrasts. SHERM, however, only requires a brain template mask as the input and is shown to automatically and reliably extract the brain tissue in both rat and mouse MRI images. fastClean is an unsupervised deep learning method that removes rsfMRI artifacts induced by the scanner, head motion, and non-neural physiological noise. Existing machine learning methods either perform unsatisfactorily in low-dimensional rodent data or suffer from long online training. With an efficient network architecture and meta-learning techniques, fastClean generates equivalently clean or cleaner data in minutes on both rodent and human datasets. Finally, we systematically investigated the spatiotemporal dynamics of spontaneous brain activity in the awake rat brain with a graph-based data mining method. We found that brain activity traverse among multiple resting-state functional connectivity patterns with nonrandom and reproducible sequential orders and time delays, r
A framework based on a complex dynamical system viewpoint for formulating and solving dynamic ice-structure interaction problems is introduced. Important constituents required for formulating a well posed initial-boun...
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ISBN:
(纸本)9780791844335
A framework based on a complex dynamical system viewpoint for formulating and solving dynamic ice-structure interaction problems is introduced. Important constituents required for formulating a well posed initial-boundary value problem are discussed. Significance of these constituents is illustrated using a Cohesive Element model of several example problems.
The digitization of the world has also led to a digitization of communication processes. Traditional research methods fall short in understanding communication in digital worlds as the scope has become too large in vo...
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ISBN:
(纸本)9781728125664
The digitization of the world has also led to a digitization of communication processes. Traditional research methods fall short in understanding communication in digital worlds as the scope has become too large in volume, variety, and velocity to be studied using traditional approaches. In this paper, we present computational methods and their use in public and mass communication research and how those could be adapted to professional communication research. The paper is a proposal for a panel in which the panelists, each an expert in their field, will present their current work using computational methods and will discuss transferability of these methods to professional communication.
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