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All Articles in Dynamics and Dynamical Systems

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153 full-text articles. Page 6 of 7.

Green Scheduling For Radiant Systems In Buildings, Truong X. Nghiem, Madhur Behl, George J. Pappas, Rahul Mangharam 2012 University of Pennsylvania

Green Scheduling For Radiant Systems In Buildings, Truong X. Nghiem, Madhur Behl, George J. Pappas, Rahul Mangharam

Real-Time and Embedded Systems Lab (mLAB)

In this report we look at the problem of peak power reduction for buildings with electric radiant floor heating systems. Uncoordinated operation of a multi-zone radiant floor heating system can result in temporally correlated electricity demand surges or peaks in the building’s electricity consumption. As peak power prices are 200-400 times that of the nominal rate, this uncoordinated activity can result in high electricity costs and expensive system operation. We have previously presented green scheduling as an approach for reducing the aggregate peak power consumption in buildings while ensuring that indoor thermal comfort is always maintained. This report extends ...


Dynamical Properties Of Ferroelectric Perovskites (Ba,Sr)Tio3 And Pb(Zr,Ti)O3 Systems From First Principles, Jeevaka Weerasinghe 2012 University of Arkansas, Fayetteville

Dynamical Properties Of Ferroelectric Perovskites (Ba,Sr)Tio3 And Pb(Zr,Ti)O3 Systems From First Principles, Jeevaka Weerasinghe

Theses and Dissertations

A first-principles-based effective Hamiltonian scheme which incorporates coupling between ferroelectric (FE) and antiferrodistortive (AFD) motions is applied to Pb(Zr,Ti)O3 alloys. It validates the existence of two modes of E symmetry (rather than the single E(1TO) soft mode) in the 50-75 cm-1 range for temperatures smaller than 200 K and for compositions falling within the Rhombohedral R3c phase. Coupling between long-range-ordered FE and AFD motions is shown to be the cause of the additional mode and more insight into its nature is provided. This scheme is further used to reveal a field-induced anticrossing involving FE ...


Switch Yard Operation In Thermal Power Plant(Katpp Jhalawar Rajasthan), RADHEY SHYAM MEENA Er. 2012 Rajasthan Technical University Kota

Switch Yard Operation In Thermal Power Plant(Katpp Jhalawar Rajasthan), Radhey Shyam Meena Er.

Radhey Shyam Meena

Switchyard Provides the facilities for switching ,protection & Control of electric power. To handle high Voltage power with proper Safety measures. To isolate the noises coming from the grid with true 50Hz power SWITCH YARD IS IMPORTANT PART IN THERMAL PLANT. IN KALISINDH THERMAL 400KV AND 220KV SWITCH YARD LOCATED.


Molecular Dynamics Study Of Diffusion Of O2 Penetrates In Uncrosslinked Polydimethysiloxane (Pdms), Crosslinked Pdms, And Pdms-Based Nanocomposites, Varun Ullal 2012 University of Arkansas, Fayetteville

Molecular Dynamics Study Of Diffusion Of O2 Penetrates In Uncrosslinked Polydimethysiloxane (Pdms), Crosslinked Pdms, And Pdms-Based Nanocomposites, Varun Ullal

Theses and Dissertations

Molecular dynamics simulations are used to study diffusion of O2 molecules in pure polydimethysiloxane (PDMS), crosslinked PDMS, and PDMS-based nanocomposites. The PDMS chains and penetrates are modeled using a hybrid interatomic potential which treats the Si-O atoms along the chain backbone explicitly while coarse-graining the methyl side groups and penetrates. By tracking the diffusion of penetrates in the system and subsequently computing their mean-squared displacement, diffusion coefficients are obtained. In pure PDMS models of varying molecular weight, diffusivity of the O22 penetrates is found to have an inverse relationship with chain length. Simulation models with longer chains ...


A Gps-Based Mobility Power Model For Military Vehicle Applications, George William Bozdech 2012 University of Tennessee, Knoxville

A Gps-Based Mobility Power Model For Military Vehicle Applications, George William Bozdech

Masters Theses

In recent years, military vehicles have been equipped with hybrid, diesel-electric drives to improve fuel efficiency and stealth capabilities. These vehicles require an accurate estimate of the power duty cycles during distinct operating conditions. To meet this demand, a GPS-based mobility power and duty cycle analysis is one approach to predict the power requirements of on-road and off-road vehicles. The dynamic vehicle parameters needed to estimate the forces developed during locomotion are determined from the GPS tracking data, and these forces include the following: the motion resistance, gravitational, linear inertia, rotational inertia, and aerodynamic drag. The motion resistance force generated ...


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

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 2012 Nanyang Technological University, Singapore

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 2012 Wroclaw University of Technology

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

Wojciech Budzianowski

No abstract provided.


Materiały Odstresowujące, Wojciech M. Budzianowski 2012 Wroclaw University of Technology

Materiały Odstresowujące, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.


Hydrogen Production From Biogas By Oxy-Reforming: Reaction System Analysis, Aleksandra Terlecka, Wojciech M. Budzianowski 2011 Wroclaw University of Technology

Hydrogen Production From Biogas By Oxy-Reforming: Reaction System Analysis, Aleksandra Terlecka, Wojciech M. Budzianowski

Wojciech Budzianowski

Oxy-reforming is emerging as an interesting alternative to conventional methods of hydrogen generation. The current article characterises this process through analysis of individual reactions: SMR (steam methane reforming), WGS (water gas shift) and CPO (catalytic partial oxidation). Analyses relate to optimisation of thermal conditions thus enabling cost-effectivenes of the process.


Relationship Between Impact Energy And Fracture Toughness Of Prestressed Concrete Railway Sleepers, Sakdirat Kaewunruen, Alexander Remennikov 2011 RailCorp

Relationship Between Impact Energy And Fracture Toughness Of Prestressed Concrete Railway Sleepers, Sakdirat Kaewunruen, Alexander Remennikov

Alex Remennikov

The prestressed concrete sleepers (or railroad ties), which are installed in railway track systems as the crosstie beam support, are designed to carry and transfer the wheel loads from the rails to the ground. It is well known that railway tracks are subject to impact loading conditions, which are attributable to the train operations with either wheel or rail abnormalities such as flat wheels, dipped rails, etc. These loads are of very high magnitude but short duration. In addition, there exists the potential of repeated load experience during the design life of prestressed concrete sleepers. Prestressed concrete has played a ...


Dynamic Design Guidelines For Prestressed Concrete Sleepers, Alexander Remennikov, Martin H. Murray, Sakdirat Kaewunruen 2011 University of Wollongong

Dynamic Design Guidelines For Prestressed Concrete Sleepers, Alexander Remennikov, Martin H. Murray, Sakdirat Kaewunruen

Alex Remennikov

Current design philosophy, outlined in AS 1085.14, is based on the analysis of permissible stresses resulting from quasi-static wheel loads and essentially the static response of concrete sleepers. In general, cracking can incur when the bottom fibre stress is larger than tensile strength of concrete. Premature cracking of prestressed concrete sleepers has been detected in railway tracks. The major cause of cracking is the infrequent but high-magnitude wheel loads produced by a small percentage of “out-of-round” wheels or railhead surface defects, which are crudely accounted for in AS 1085.14 by a single load factor. Based on the current ...


Vibration-Based Health Monitoring Of Multiple-Stage Gear Train And Differential Planetary Transmission Involving Teeth Damage And Backlash Nonlinearity, Andrew Patrick Sommer 2011 California Polytechnic State University - San Luis Obispo

Vibration-Based Health Monitoring Of Multiple-Stage Gear Train And Differential Planetary Transmission Involving Teeth Damage And Backlash Nonlinearity, Andrew Patrick Sommer

Master's Theses and Project Reports

The objective of this thesis is to develop vibration-based fault detection strategies for on-line condition monitoring of gear transmission systems. The study divides the thesis into three sections. First of all, the local stresses created by a root fatigue crack on a pinion spur gear are analyzed using a quasi-static finite element model and non-linear contact mechanics simulation. Backlash between gear teeth which is essential to provide better lubrication on tooth surfaces and to eliminate interference is included as a defect and a necessary part of transmission design. The second section is dedicated to fixed axis power trains. Torsional vibration ...


Coordination Of Multirobot Teams And Groups In Constrained Environments: Models, Abstractions, And Control Policies, Nora Ayanian 2011 University of Pennsylvania

Coordination Of Multirobot Teams And Groups In Constrained Environments: Models, Abstractions, And Control Policies, Nora Ayanian

Publicly Accessible Penn Dissertations

Robots can augment and even replace humans in dangerous environments, such as search and rescue and reconnaissance missions, yet robots used in these situations are largely tele-operated. In most cases, the robots' performance depends on the operator's ability to control and coordinate the robots, resulting in increased response time and poor situational awareness, and hindering multirobot cooperation.

Many factors impede extended autonomy in these situations, including the unique nature of individual tasks, the number of robots needed, the complexity of coordinating heterogeneous robot teams, and the need to operate safely. These factors can be partly addressed by having many ...


Development And Analysis Of Onboard Translunar Injection Targeting Algorithms, Phillippe Lyles Winters Reed 2011 University of Tennessee, Knoxville

Development And Analysis Of Onboard Translunar Injection Targeting Algorithms, Phillippe Lyles Winters Reed

Masters Theses

Several targeting algorithms are developed and analyzed for possible future use onboard a spacecraft. Each targeter is designed to determine the appropriate propulsive burn for translunar injection to obtain desired orbital parameters upon arrival at the moon. Primary design objectives are to minimize the computational requirements for each algorithm but also to ensure reasonable accuracy, so that the algorithm’s errors do not force the craft to conduct large mid-course corrections. Several levels of accuracy for dynamical models are explored, the convergence range and speed of each algorithm are compared, and the possible benefits of the Broyden and trust-region targeters ...


Adaptive Discrete-Time Controller Design With Neural Network For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu 2011 Nanyang Technological University, Singapore

Adaptive Discrete-Time Controller Design With Neural Network For Hypersonic Flight Vehicle Via Back-Stepping, Bin Xu

Bin Xu

In this article, the adaptive neural controller in discrete time is investigated for the longitudinal dynamics of a generic hypersonic flight vehicle. The dynamics are decomposed into the altitude subsystem and the velocity subsystem. The altitude subsystem is transformed into the strict-feedback form from which the discrete-time model is derived by the first-order Taylor expansion. The virtual control is designed with nominal feedback and neural network (NN) approximation via back-stepping. Meanwhile, one adaptive NN controller is designed for the velocity subsystem. To avoid the circular construction problem in the practical control, the design of coefficients adopts the upper bound instead ...


Adaptive Neural Control Based On Hgo For Hypersonic Flight Vehicles, Bin Xu 2011 Nanyang Technological University, Singapore

Adaptive Neural Control Based On Hgo For Hypersonic Flight Vehicles, Bin Xu

Bin Xu

This paper describes the design of adaptive neural controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV) which are decomposed into two functional systems, namely the altitude subsystem and the velocity subsystem. For each subsystem, one adaptive neural controller is investigated based on the normal output-feedback formulation. For the altitude subsystem, the high gain observer (HGO) is taken to estimate the unknown newly defined states. Only one neural network (NN) is employed to approximate the lumped uncertain system nonlinearity during the controller design which is considerably simpler than the ones based on back-stepping scheme with the strict-feedback ...


Task Allocation For Multi-Spacecraft Cooperation Based On Estimation Of Distribution Algorithm, Bin Xu 2011 Nanyang Technological University, Singapore

Task Allocation For Multi-Spacecraft Cooperation Based On Estimation Of Distribution Algorithm, Bin Xu

Bin Xu

One two-stage task allocation strategy is proposed for multi-spacecraft cooperation during the long-range orbit transfer with two impulses. This paper focuses on the task value maximum and cost minimum optimization by assigning spacecraft to different task. At the first stage time and energy cost are considered based on the spacecraft dynamics. The optimization result is together with the target value as the factor for the task allocation model at the second stage. The optimization is processed separately in continuous and discrete time domain with estimation of distribution algorithm (EDA). Different task allocation mode is formulated and the strategy is verified ...


Composite Control Based On Optimal Torque Control And Adaptive Kriging Control For The Crab Rover, Bin Xu 2011 Nanyang Technological University, Singapore

Composite Control Based On Optimal Torque Control And Adaptive Kriging Control For The Crab Rover, Bin Xu

Bin Xu

Terrainability is mostly dependant on the suspension mechanism and the control of a space rover. For the six wheeled CRAB rover, this paper presents the composite control design with torque control and adaptive Kriging control to improve the terrainability, somewhat related to minimizing heel slip. As CRAB is moving slowly, the torque control is processed by minimizing the variance of the required friction coefficient based on the static model. Adaptive Kriging control is used to track the commanded velocity. The system uncertainty is compensated by Kriging estimation based on the velocity dynamics. Experiment results with two different tires show the ...


Adaptive Hypersonic Flight Control Via Back-Stepping And Kriging Estimation, Bin Xu 2011 Nanyang Technological University, Singapore

Adaptive Hypersonic Flight Control Via Back-Stepping And Kriging Estimation, Bin Xu

Bin Xu

This paper investigates the adaptive Kriging controller for the longitudinal dynamics of a generic hypersonic flight vehicle (HFV). For the altitude subsystem, the dynamics are transformed into the strict-feedback form where the backstepping scheme is employed. Considering the nonlinearity of the dynamics, the nominal feedback is included in the controller while Kriging system is designed to estimate the uncertainty. With the proposed controller, the almost surely bounded stability is guaranteed. The simulation study is presented to show the effectiveness of the proposed control approach.


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