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Computational Engineering Commons

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2012

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Articles 1 - 30 of 36

Full-Text Articles in Computational Engineering

Modelling Three-Phase Flow In Metallurgical Processes, Christoph Goniva, Gijsbert Wierink, Kari Heiskanen, Stefan Pirker, Christoph Kloss Dec 2012

Modelling Three-Phase Flow In Metallurgical Processes, Christoph Goniva, Gijsbert Wierink, Kari Heiskanen, Stefan Pirker, Christoph Kloss

Gijsbert Wierink

The interaction between gasses, liquids, and solids plays a critical role in many processes, such as coating, granulation and the blast furnace process. In this paper we present a comprehensive numerical model for three phase flow including droplets, particles and gas. By means of a coupled Computational Fluid Dynamics (CFD) - Discrete Element Method (DEM) approach the physical core phenomena are pictured at a detailed level. Sub-models for droplet deformation, breakup and coalescence as well as droplet-particle and wet particle-particle interaction are applied. The feasibility of this model approach is demonstrated by its application to a rotating drum coater. The described ...


Fluid–Structure Interaction Modeling Of Wind Turbines: Simulating The Full Machine, Ming-Chen Hsu, Yuri Bazilevs Dec 2012

Fluid–Structure Interaction Modeling Of Wind Turbines: Simulating The Full Machine, Ming-Chen Hsu, Yuri Bazilevs

Ming-Chen Hsu

In this paper we present our aerodynamics and fluid–structure interaction (FSI) computational techniques that enable dynamic, fully coupled, 3D FSI simulation of wind turbines at full scale, and in the presence of the nacelle and tower (i.e., simulation of the “full machine”). For the interaction of wind and flexible blades we employ a nonmatching interface discretization approach, where the aerodynamics is computed using a low-order finite-element-based ALE-VMS technique, while the rotor blades are modeled as thin composite shells discretized using NURBS-based isogeometric analysis (IGA). We find that coupling FEM and IGA in this manner gives a good combination ...


Kernel-Assisted And Topology-Aware Mpi Collective Communication Among Multicore Or Many-Core Clusters, Teng Ma Dec 2012

Kernel-Assisted And Topology-Aware Mpi Collective Communication Among Multicore Or Many-Core Clusters, Teng Ma

Doctoral Dissertations

Multicore or many-core clusters have become the most prominent form of High Performance Computing (HPC) systems. Hardware complexity and hierarchies not only exist in the inter-node layer, i.e., hierarchical networks, but also exist in internals of multicore compute nodes, e.g., Non Uniform Memory Accesses (NUMA), network-style interconnect, and memory and shared cache hierarchies.

Message Passing Interface (MPI), the most widely adopted in the HPC communities, suffers from decreased performance and portability due to increased hardware complexity of multiple levels. We identified three critical issues specific to collective communication: The first problem arises from the gap between logical collective ...


The Unstructured Grid Incompressible Navier-Stokes Algorithm For Convective Heat Transfer Based On Artificial Compressibility, Jessica Elaine Kress Dec 2012

The Unstructured Grid Incompressible Navier-Stokes Algorithm For Convective Heat Transfer Based On Artificial Compressibility, Jessica Elaine Kress

Masters Theses and Doctoral Dissertations

The development of an explicit unstructured grid finite-volume scheme for solving the full incompressible Navier-Stokes equations along with the energy equation in a strongly coupled manner is presented. The Boussinesq approximation is utilized to account for thermal buoyancy. The method of artificial compressibilty is used to solve the resulting equations in a time marching fashion. Roe's approximate Riemann solver is used for the construction of the numerical flux. An eigensystem is derived for the flux Jacobian matrix, which is used in the evaluation of the numerical flux and the characteristic variable boundary conditions. The resulting algorithm is validated by ...


Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza Nov 2012

Stochastic Optimal Control In Nonlinear Systems, Celestin Nkundineza

Celestin Nkundineza

Stochastic control is an important area of research in engineering systems that undergo disturbances. Controlling individual states in such systems is critical. The present investigation is concerned with the application of the stochastic optimal control strategy developed by To (2010) and its implementation as well as providing computed results of linear and nonlinear systems under stationary and nonstationary random excitations. In the strategy the feedback matrix is designed based on the achievement of the objectives for individual states in the system through the application of the Lyapunov equation for the system. Each diagonal element in the gain or associated gain ...


Monotonic And Cyclic Behaviour Of Steel Fibre-Reinforced And Frp-Steel Fibre-Reinforced Helical Pulldown Micropiles, Mahmoud Meckkey M. El Sharnouby Oct 2012

Monotonic And Cyclic Behaviour Of Steel Fibre-Reinforced And Frp-Steel Fibre-Reinforced Helical Pulldown Micropiles, Mahmoud Meckkey M. El Sharnouby

Electronic Thesis and Dissertation Repository

Helical piles are a deep foundation system that can be used to support pipelines, telecommunication and transmission towers, and low- and medium-rise buildings. Advantages of helical piles include: short installation time with minimal noise and vibration levels; can be installed with ease in limited accessibility site; and onsite quality control by measurement of installation torque.

The main objective of the current research is to assess the performance of steel fibre-reinforced helical pulldown micropiles (RHPM), and fibre-reinforced polymer-steel fibre- reinforced pulldown micropiles (FRP-RHPM) under axial and lateral monotonic and cyclic loading conditions.

The research methodology involved conducting full scale field testing ...


Real-Time Heart Model For Implantable Cardiac Device Validation And Verification, Zhihao Jiang, Miroslav Pajic, Allison T. Connolly, Sanjay Dixit, Rahul Mangharam Oct 2012

Real-Time Heart Model For Implantable Cardiac Device Validation And Verification, Zhihao Jiang, Miroslav Pajic, Allison T. Connolly, Sanjay Dixit, Rahul Mangharam

Rahul Mangharam

Designing bug-free medical device software is difficult, especially in complex implantable devices that may be used in unanticipated contexts. Safety recalls of pacemakers and implantable cardioverter defibrillators due to firmware problems between 1990 and 2000 affected over 200,000 devices, comprising 41% of the devices recalled and are increasing in frequency. There is currently no formal methodology or open experimental platform to validate and verify the correct operation of medical device software. To this effect, a real-time Virtual Heart Model (VHM) has been developed to model the electrophysiological operation of the functioning (i.e. during normal sinus rhythm) and malfunctioning ...


Tone-2 Tones Discrimination Task Comparing Audio And Haptics, Lorenzo Picinali, Christopher Feakes, Davide Andrea Mauro, Brian F. G. Katz Oct 2012

Tone-2 Tones Discrimination Task Comparing Audio And Haptics, Lorenzo Picinali, Christopher Feakes, Davide Andrea Mauro, Brian F. G. Katz

Weisberg Division of Computer Science Faculty Research

To investigating the capabilities of human beings to differentiate between tactile-vibratory stimuli with the same fundamental frequency but with different spectral content, this study concerns discrimination tasks comparing audio and haptic performances. Using an up-down 1 dB step adaptive procedure, the experimental protocol consists of measuring the discrimination threshold between a pure tone signal and a stimulus composed of two concurrent pure tones, changing the amplitude and frequency of the second tone. The task is performed employing exactly the same experimental apparatus (computer, AD-DA converters, amplifiers and drivers) for both audio and tactile modalities. The results show that it is ...


Primitivec-Adl: Primitive Component Architecture Description Language, Basel Magableh Sep 2012

Primitivec-Adl: Primitive Component Architecture Description Language, Basel Magableh

Articles

In this paper, we introduce an architecture descrip- tion language (ADL) for PCOMs (a context oriented component model). The language is described at three levels: (1) Building blocks (PCOMs context oriented components types) (2) Connec- tors, which connect components externally and internally, and (3) Architectural Configuration, which includes a full description of composition and decomposition mechanisms.

The contribution is designing ADL. That supports context- orinted component by providing new architecture elements, which fulfil the requirements of designing context oriented component based applications. Context oriented component is a behavioural unit composed of static parts and dynamic parts. A PCOMs component model ...


Enhancing Reliability In Passive Anti-Islanding Protection Schemes For Distribution Systems With Distributed Generation, Mohsen Sheikholeslamzadeh Sep 2012

Enhancing Reliability In Passive Anti-Islanding Protection Schemes For Distribution Systems With Distributed Generation, Mohsen Sheikholeslamzadeh

Electronic Thesis and Dissertation Repository

This thesis introduces a new approach to enhance the reliability of conventional passive anti-islanding protection scheme in distribution systems embedding distributed generation. This approach uses an Islanding-Dedicated System (IDS) per phase which will be logically combined with the conventional scheme, either in blocking or permissive modes. Each phase IDS is designed based on data mining techniques. The use of Artificial Neural Networks (ANNs) enables to reach higher accuracy and speed among other data mining techniques. The proposed scheme is trained and tested on a practical radial distribution system with six-1.67 MW Doubly-Fed Induction Generators (DFIG-DGs) wind turbines. Various scenarios ...


Tweeting For Learning: A Critical Analysis Of Research On Microblogging In Education Published In 2008-2011, Fei Gao, Tian Luo, Ke Zhang Sep 2012

Tweeting For Learning: A Critical Analysis Of Research On Microblogging In Education Published In 2008-2011, Fei Gao, Tian Luo, Ke Zhang

Visual Communication and Technology Education Faculty Publications

This study critically analyzed the current body of published research on microblogging in education (MIE) to build a deep and comprehensive understanding of this increasingly popular phenomenon. Twenty-one studies on MIE in 2008-2011 were selected based on the selection criteria and analyzed to answer the following questions: (a) What types of research have been published on MIE? (b) How was microblogging used for teaching and learning in these studies? (c) What educational benefits did microblogging have on teaching and learning? and (d) What suggestions and implications did the current research have for future MIE research and practices? The analysis suggested ...


A Validation Study Of The Amp Nuclear Fuel Performance Code, Aaron Martin Phillippe Aug 2012

A Validation Study Of The Amp Nuclear Fuel Performance Code, Aaron Martin Phillippe

Masters Theses

The Advanced Multi-Physics (AMP) Fuel Performance Code is a fully coupled, 3-dimensional (3D) code currently in development at the Oak Ridge National Laboratory (ORNL) for the purposes of advanced fuel performance evaluation and simulation. The purpose of this study was to investigate and examine the capabilities of AMP, as developed so far, in thermo-mechanical evaluations of experimental benchmark data. The IFA-432 and IFA-597 datasets from the Nuclear Energy Agency’s (NEA) International Fuel Performance Experiments (IFPE) database were examined, and a code-to-code comparison made against FRAPCON-3.4, a one dimensional (1D) code used by the Nuclear Regulatory Commission (NRC) for ...


Analysis And Implementation Of A High-Order Reconstruction Algorithm For An Unstructured Finite Volume Flow Solver, Shane Edmond Sawyer Aug 2012

Analysis And Implementation Of A High-Order Reconstruction Algorithm For An Unstructured Finite Volume Flow Solver, Shane Edmond Sawyer

Masters Theses and Doctoral Dissertations

A high-order scheme is examined an implemented in an unstructured solver. The motivation for this researcher is driven by research goals to simulate field equations, particularly those of fluid dynamics, with high fidelity. High-order schemes overcome computational limitations by computing comparable solutions on grids that are coarser than grids required by a second-order flow solver. The scheme was chosen based on two criteria. The first being that it is well documented in the literature for two-dimensional flow solvers. The second is that the scheme is extendable to the framework used in the Tenasi flow solver developed at the University of ...


Mesh Generation Using A Correspondence Distance Field, Nicholas Szapiro Aug 2012

Mesh Generation Using A Correspondence Distance Field, Nicholas Szapiro

Masters Theses and Doctoral Dissertations

The central tool of this work is a correspondence distance field to discrete surface points embedded within a quadtree data structure. The theory, development, and implementation of the distance field tool are described, and two main applications to two-dimensional mesh generation are presented with extension to three-dimensional capabilities in mind. First is a method for surface-oriented mesh generation from a sufficiently dense set of discrete surface points without connectivity information. Contour levels of distance from the body are specified and correspondences oriented normally to the contours are created. Regions of merging fronts inside and between objects are detected in the ...


Efficient Algorithms For Fast Integration On Large Data Sets From Multiple Sources, Tian Mi, Sanguthevar Rajasekaran, Robert H. Aseltine Jun 2012

Efficient Algorithms For Fast Integration On Large Data Sets From Multiple Sources, Tian Mi, Sanguthevar Rajasekaran, Robert H. Aseltine

Open Access Author Fund Awardees' Articles

Background

Recent large scale deployments of health information technology have created opportunities for the integration of patient medical records with disparate public health, human service, and educational databases to provide comprehensive information related to health and development. Data integration techniques, which identify records belonging to the same individual that reside in multiple data sets, are essential to these efforts. Several algorithms have been proposed in the literatures that are adept in integrating records from two different datasets. Our algorithms are aimed at integrating multiple (in particular more than two) datasets efficiently.

Methods

Hierarchical clustering based solutions are used to integrate ...


Real-Time Musical Analysis Of Polyphonic Guitar Audio, John E. Hartquist Jun 2012

Real-Time Musical Analysis Of Polyphonic Guitar Audio, John E. Hartquist

Master's Theses and Project Reports

In this thesis, we analyze the audio signal of a guitar to extract musical data in real-time. Specifically, the pitch and octave of notes and chords are displayed over time. Previous work has shown that non-negative matrix factorization is an effective method for classifying the pitches of simultaneous notes. We explore the effect of window size, hop length, and other parameters to maximize the resolution and accuracy of the output.

Other groups have required prerecorded note samples to build a library of note templates to search for. We automate this step and compute the library at run-time, tuning it specifically ...


Development And Verification Of A Navier-Stokes Solver With Vorticity Confinement Using Openfoam, Austin Barrett Kimbrell May 2012

Development And Verification Of A Navier-Stokes Solver With Vorticity Confinement Using Openfoam, Austin Barrett Kimbrell

Masters Theses

Vorticity Confinement (VC) is a numerical technique which enhances computation of fluid flows by acting as negative diffusion within the limit of vortical regions, preventing the inherent numerical dissipation present with conventional methods. VC shares similarities with large eddy simulation (LES), but its behavior is based on a stable negative dissipation of vortical structures controlled by the automatic balance between two parameters, μ [mu] and ε [epsilon].

In this thesis, three-dimensional, parallel-computing Navier-Stokes solvers with VC are developed using the OpenFOAM computational framework. OpenFOAM is an open-source collection of C++ libraries developed for computational fluid dynamics. Object-oriented programming concepts are ...


Vibration Of Carbon Nano-Structures, Sina Arghavan Apr 2012

Vibration Of Carbon Nano-Structures, Sina Arghavan

Electronic Thesis and Dissertation Repository

In this thesis, first the fundamental characterizations of carbon nano-structures and basic atomistic models of the carbon nanotubes and graphitic sheets are reviewed extensively. Different simulation methods used in this field of study are discussed critically. Advantages and shortfalls of each method are reported in detail. A new structural approach based on the lattice atomic structure is selected as an accurate and efficient model for simulating carbon nano-structures. This method is used comprehensively in the present work along with continuous shell and plate theories to study the mechanical and vibrational characteristics of single-walled carbon nanotubes and single and multi-layered graphene ...


The Implementation Of A Visco-Hyperelastic Numerical Material Model For Simulating The Behaviour Of Polymer Foam Materials, Conor Briody, Barry Duignan, Stephen Jerrams, John Tiernan Apr 2012

The Implementation Of A Visco-Hyperelastic Numerical Material Model For Simulating The Behaviour Of Polymer Foam Materials, Conor Briody, Barry Duignan, Stephen Jerrams, John Tiernan

Articles

Polyurethane foam has been in use for some time in wheelchair seating systems as it offers good pressure relieving capabilities in most cases. However, little characterisation work has gone into seating foam materials by comparison with conventional elastomeric materials. Accurate material models could allow better prediction of foam in-service behaviour, which could potentially improve seating design practises. The objective of this work was to develop an approach for the validation of hyperelastic and viscoelastic material model parameters used to simulate polyurethane foam behaviour. Material parameters were identified from relevant test procedures and implemented in a Finite Element simulation of an ...


Polaris: Getting Accurate Indoor Orientations For Mobile Devices Using Ubiquitous Visual Patterns On Ceilings, Zheng Sun Feb 2012

Polaris: Getting Accurate Indoor Orientations For Mobile Devices Using Ubiquitous Visual Patterns On Ceilings, Zheng Sun

Zheng Sun

Ubiquitous computing applications commonly use digital compass sensors to obtain orientation of a device relative to the magnetic north of the earth. However, these compass readings are always prone to significant errors in indoor environments due to presence of metallic objects in close proximity. Such errors can adversely affect the performance and quality of user experience of the applications utilizing digital compass sensors.

In this paper, we propose Polaris, a novel approach to provide reliable orientation information for mobile devices in indoor environments. Polaris achieves this by aggregating pictures of the ceiling of an indoor environment and applies computer vision ...


Relative Performance Of Mutual Information Estimation Methods For Quantifying The Dependence Among Short And Noisy Data, Shiraj Khan, Sharba Bandyopadhyay, Auroop R. Ganguly, Sunil Saigal, David J. Erickson Iii, Vladimir Protopopescu, George Ostrouchov Jan 2012

Relative Performance Of Mutual Information Estimation Methods For Quantifying The Dependence Among Short And Noisy Data, Shiraj Khan, Sharba Bandyopadhyay, Auroop R. Ganguly, Sunil Saigal, David J. Erickson Iii, Vladimir Protopopescu, George Ostrouchov

Auroop R. Ganguly

Commonly used dependence measures, such as linear correlation, cross-correlogram, or Kendall's τ, cannot capture the complete dependence structure in data unless the structure is restricted to linear, periodic, or monotonic. Mutual information (MI) has been frequently utilized for capturing the complete dependence structure including nonlinear dependence. Recently, several methods have been proposed for the MI estimation, such as kernel density estimators (KDEs), k-nearest neighbors (KNNs), Edgeworth approximation of differential entropy, and adaptive partitioning of the XY plane. However, outstanding gaps in the current literature have precluded the ability to effectively automate these methods, which, in turn, have caused limited ...


Effective Calculation Of Multiple Solutions Of Mixed Convection In A Porous Medium, Saeid Abbasbandy, E. Shivanian Jan 2012

Effective Calculation Of Multiple Solutions Of Mixed Convection In A Porous Medium, Saeid Abbasbandy, E. Shivanian

Saeid Abbasbandy

This paper considers an important model of boundary value problem with a condition at infinity namely combined free and forced convection over a plane of arbitrary shape embedded in a fluid-saturated porous medium; this model admits dual solutions, and uses a technique, which is to some extent modification of homotopy analysis method (HAM), in order to obtain dual solutions analytically with high accuracy.


Comparing Qos Of Dsdv And Aodv Routing Protocols In Vehicular Network, Aref Hassanpour, Hooman Hoodeh, Amirhossein Zarrinnegar, Arsalan Emami, Rafidah Md Noor Jan 2012

Comparing Qos Of Dsdv And Aodv Routing Protocols In Vehicular Network, Aref Hassanpour, Hooman Hoodeh, Amirhossein Zarrinnegar, Arsalan Emami, Rafidah Md Noor

Hooman Hoodeh

With the advance of Vehicular ad-hoc network, routing protocol has become one of the most important issues in transmitting data among Vehicles. The two routing protocol are DSDV and AODV which DSDV is known as a novel approach in proactive system; however, AODV has good performance in reactive system. In this paper, we compare the efficiency between DSDV & AODV in terms of packet-loss, end-to-end delay and throughput based on given scenarios. The comparison has implemented in various speeds for acquiring result with higher performance. The speeds consist of 5, 20 and 40km/s. then we analyze the explicit results according ...


Adaptive Kriging Controller Design For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu Jan 2012

Adaptive Kriging Controller Design For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu

Bin Xu

No abstract provided.


Direct Neural Discrete Control Of Hypersonic Flight Vehicle, Bin Xu Jan 2012

Direct Neural Discrete Control Of Hypersonic Flight Vehicle, Bin Xu

Bin Xu

No abstract provided.


Ogólnotechniczne Podstawy Biotechnologii Z Elementami Grafiki Inżynierskiej Ćw., Wojciech M. Budzianowski Jan 2012

Ogólnotechniczne Podstawy Biotechnologii Z Elementami Grafiki Inżynierskiej Ćw., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Materiały Odstresowujące, Wojciech M. Budzianowski Jan 2012

Materiały Odstresowujące, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


A Combined Quadtree/Delaunay Method For 2d Mesh Generation, Simon Tang Jan 2012

A Combined Quadtree/Delaunay Method For 2d Mesh Generation, Simon Tang

Masters Theses 1911 - February 2014

Unstructured simplicial mesh is an integral and critical part of many computational electromagnetics methods (CEM) such as the finite element method (FEM) and the boundary element method (BEM). Mesh quality and robustness have direct impact on the success of these CEM methods.

A combined quadtree/Delunay 2D mesh generator, based on the early work of Schroeder (1991, PhD), is presented. The method produces a triangulation that approximates the original geometric model but is also topologically consistent. The key advantages of the method are: (a) its robustness, (b) ability to create a-priori graded meshes, and (c) its guaranteed mesh quality.

The ...


A Numerical Study On Hydraulic Characteristics In The Ice Harbor-Type Fishway, Seojun Kim, Kwonkyu Yu, Byungman Yoon, Yoonsung Lim Jan 2012

A Numerical Study On Hydraulic Characteristics In The Ice Harbor-Type Fishway, Seojun Kim, Kwonkyu Yu, Byungman Yoon, Yoonsung Lim

Journal Articles

Recently various types of fishways have been developed and constructed in order to preserve diversity of fish species and restore the riverine ecological system. Some of the fishways in Korea, however, seem to be designed and installed without careful study on their functions and swimming characteristics of target fishes. The present study aims to elucidate proper hydraulic characteristics of the Ice Harbor-type fishway. In the present study, we analyzed the hydraulic characteristics depending on changes in the spans of walls in the Ice Harbor-type fishways, by using Flow-3D, a three dimensional numerical simulation program. Two physical experiments were performed to ...


High Speed Flow Simulation In Fuel Injector Nozzles, Sukanta Rakshit Jan 2012

High Speed Flow Simulation In Fuel Injector Nozzles, Sukanta Rakshit

Masters Theses 1911 - February 2014

Atomization of fuel is essential in controlling combustion inside a direct injection engine. Controlling combustion helps in reducing emissions and boosting efficiency. Cavitation is one of the factors that significantly affect the nature of spray in a combustion chamber. Typical fuel injector nozzles are small and operate at a very high pressure, which limit the study of internal nozzle behavior. The time and length scales further limit the experimental study of a fuel injector nozzle. Simulating cavitation in a fuel injector will help in understanding the phenomenon and will assist in further development.

The construction of any simulation of cavitating ...