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Full-Text Articles in Engineering

Propagation Of Uncertainty Through Coning, Sculling, And Scrolling Corrections For Inertial Navigation, James Daniel Alan Brouk Jan 2019

Propagation Of Uncertainty Through Coning, Sculling, And Scrolling Corrections For Inertial Navigation, James Daniel Alan Brouk

Masters Theses

"This thesis investigates the propagation of estimation errors through generalized coning, sculling, and scrolling algorithms used in modern day inertial navigation systems, in order to accurately quantify the uncertainty in the estimation of position, velocity, and attitude. The corrections for coning, sculling, and scrolling algorithms have an often unaccounted for effect on documented and empirically derived error statistics for measurements used to predict the uncertainty in a vehicle's position, velocity, and attitude estimates. Through the development of an error analysis for these generalized algorithms, mappings of the measurement and estimation errors through the correction termare generated. Using the developed ...


Time-Dependent Reliability Methodologies With Saddlepoint Approximation, Zhangli Hu Jan 2019

Time-Dependent Reliability Methodologies With Saddlepoint Approximation, Zhangli Hu

Doctoral Dissertations

"Engineers always encounter time-dependent uncertainties that ubiquitously exist, such as the random deterioration of material properties and time-variant loads. Therefore the reliability of engineering systems becomes time-dependent. It is crucial to predict the time-dependent reliability in the design stage, given possible catastrophic consequences of a failure. Although extensive research has been conducted on reliability analysis, estimating the reliability accurately and efficiently is still challenging. The objective of this work is to develop accurate and efficient reliability methodologies for engineering design. The basic idea is the integration of traditional reliability methods with saddlepoint approximation (SPA), which can accurately approximate the tail ...


Effects Of Uncertainty Refinement On Satellite Collision Probability, Bruce Thomas Morrison Jan 2019

Effects Of Uncertainty Refinement On Satellite Collision Probability, Bruce Thomas Morrison

Masters Theses

"Due to the drastic increase in orbital debris about the Earth, the likelihood for new and current mission satellites to collide with other objects grows. When a mission satellite is placed in a highly populated orbit in the vicinity of other satellites or debris, it is necessary to consider the probability of collision to assess any possible conjunctions. The computation of the collision probability is heavily dependent on the relative position and velocity of the objects during conjunction, as well as the combined covariance. There are two main types of analytic collision probability computations; the first assumes that the objects ...


Managing Risks Of Market Price Uncertainty For A Microgrid Operation, Sriram Raghavan Jan 2016

Managing Risks Of Market Price Uncertainty For A Microgrid Operation, Sriram Raghavan

Masters Theses

"After deregulation of electricity in the United States, the day-ahead and real-time markets allow load serving entities and generation companies to bid and purchase/sell energy under the supervision of the independent system operator (ISO). The electricity market prices are inherently uncertain, and can be highly volatile. The main objective of this thesis is to hedge against the risk from the uncertainty of the market prices when purchasing/selling energy from/to the market. The energy manager can also schedule distributed generators (DGs) and storage of the microgrid to meet the demand, in addition to energy transactions from the market ...


Efficient Time-Dependent System Reliability Analysis, Zhifu Zhu Jan 2016

Efficient Time-Dependent System Reliability Analysis, Zhifu Zhu

Doctoral Dissertations

"Engineering systems are usually subjected to time-variant loads and operate under time-dependent uncertainty; system performances are therefore time-dependent. Accurate and efficient estimate of system reliability is crucial for decision makings on system design, lifetime cost estimate, maintenance strategy, etc. Although significant progresses have been made in time-independent reliability analysis for components and systems, time-dependent system reliability methodologies are still limited. This dissertation is motivated by the need of accurate and effective reliability prediction for engineering systems under time-dependent uncertainty. Based on the classic First and Second Order Reliability Method (FORM and SORM), a system reliability method is developed for multidisciplinary ...


Probabilistic Engineering Analysis And Design Under Time-Dependent Uncertainty, Zhen Hu Jan 2014

Probabilistic Engineering Analysis And Design Under Time-Dependent Uncertainty, Zhen Hu

Doctoral Dissertations

"Time-dependent uncertainties, such as time-variant stochastic loadings and random deterioration of material properties, are inherent in engineering applications. Not considering these uncertainties in the design process may result in catastrophic failures after the designed products are put into operation. Although significant progress has been made in probabilistic engineering design, quantifying and mitigating the effects of time-dependent uncertainty is still challenging. This dissertation aims to help build high reliability into products under time-dependent uncertainty by addressing two research issues. The first one is to efficiently and accurately predict the time-dependent reliability while the second one is to effectively design the time-dependent ...