Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 17 of 17 for “"phase-type"”.
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Longitudinal Joint Modelling Utilising the Coxian Phase-type Distribution
… <br/> <br/>Within this thesis, the Coxian phase-type regression model is explored as a novel approach to represent the survival process within a joint model. Phase-type distributions, in general, are a diverse family of distributions which describe the absorption times of a continuous time …
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Sequential estimation of optimal age replacement policies when distribution of lifetimes is phase type.
… of lifetimes is a known, increasing failure rate phase type distribution. To find the optimal age of replacement, the parameters of the underlying phase type distribution must be estimated. An optimal age sequential estimation procedure is developed. In particular, the phase type distributions …
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The crystal stucture determination of low and high temperature phases of Tris (Ethylene Terephthalate)
… of -[O.00.C 6H 4 .CO.O.CH2 .CHJ 3 -. It has two phases, namely the Low Temperature phase (Type A) which isstable below 801C; and the High Temperature Phase (Type B) - stable between 800C and its melting temperature 320 0C. The crystal structures of these two phases have been determined by X-ray …
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Analysis and Approximations of Time Dependent Queueing Models
… from the more computationally friendly family of phase-type processes and distributions. We develop numerical approximation methods for analysis of general time-dependent queueing nodes by introducing new approximations for the time-dependent first two moments of the number-in-system and …
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Traffic processes and sojourn times in finite Markovian queues
… renewal processes with interval distributions of phase-type. The queue capacity is finite. A general class of queue disciplines are considered. The primary models studied are from the M/E<sub>k</sub>/Φ/L class. The input, output, departure and overflow processes are analyzed. Furthermore, the …
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Approximating Deterministic Changes to Ph(t)/Ph(t)/1/c and Ph(t)/M(t)/s/c Queueing Models
A deterministic change to a time-varying queueing model is described as either changing the number of entities, the queue capacity, or the number of servers in the system at selected times. We use a surrogate distribution for N(t), the number of entities in the system at time t, to approximate …
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The Ph(t)/Ph(t)/s/c Queueing Model and Approximation
Time-dependent queueing models are important since most of real-life problems are time-dependent. We develop a numerical approximation algorithm for the mean, variance and higher-order moments of the number of entities in the system at time t for the Ph(t)/Ph(t)/s/c queueing model. This model can …
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Markov Modeling of Third Generation Wireless Channels
… for these channels are also approximated using Phase-Type (PH) distribution.
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EXPLORING EQUINE ASTHMA: PATHOGENESIS INSIGHTS AND DIAGNOSTIC CHALLENGES
… SEA-affected horses predominantly exhibit late-phase type I hypersensitivity, whereas MEA-affected horses manifest type IV hypersensitivity. Furthermore, our investigations demonstrated associations between distinct immune response types and various EA severity and cytological subtypes, …
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Prediction of waiting time for entities in independent and merged queues using Markov chain and machine learning techniques
… one-infinite dimensional matrix with the help of Phase-type distribution. After solving the Quasi-birth-death process, to compare the results, a simulation method is applied; the average gap between the dimentionality reduction method and simulation results is about 7%. Moreover, two unsupervised …
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The structural effects of divalent cations and insulin on phospholipid model membranes /
… complex forms a pure hexagonal type II phase that exists from 40 to 400 C. The molar ratio of calcium and cardiolipin in the complex is 1 : 1. Cardiolipin, precipitated with magnesium and barium forms two co-existing phases, lamellar and hexagonal, the relative quantity of the …
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Time-dependence in Markovian decision processes.
… We develop a new technique, utilizing phase-type (PH) distributions, in an effort to address these complexity issues. By using PH representations, we construct a new state-space for the process, referred to as the phase-space, incorporating the phases of the state transition probability …
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Reliability Analysis and Optimization of Systems Containing Multi-Functional Entities
… model-selection method to construct the best phase-type (PH) distribution for a given data set in terms of the model complexity and the adequacy of statistical fitting. To efficiently utilize the Akaike Information Criterion for balancing the likelihood value and the number of free parameters, …
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Knowledge Discovery from Complex Event Time Data with Covariates
… such as reliability engineering, complex types of data are encountered which require novel methods of statistical analysis. Handling covariates properly while managing the missing values is a challenging task. These type of issues happen frequently in reliability data analysis. …
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Limiting Conditional Distributions: Imprecision and Relation to the Hazard Rate
… predict the shape of hazard rates generated by phase type distributions (first passage time distributions generated by atomic initial distributions) by comparing these initial distributions with the QSD. In Chapter 2 we consider these claims, and demonstrate through the use of several examples …
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Structural and magnetic characterization of Nd-based Nd-Fe and Nd-Fe-Co-Al metastable alloys
… is to characterize a metastable hard magnetic phase referred to as "A1" in Nd-Fe alloys, which forms as a part of the fine eutectic depending on the composition and cooling rate. In order to define the range of composition for the formation of A1, Nd100-xFex (x = 20, 25, 40) alloys …
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Induction generators in mini and micro hydro applications as a low cost alternative
… generator is studied to supply a single-phase or an unbalanced three-phase load using a standard three-phase machine. This scheme is particularly suitable in the micro range where the loads are generally single-phase or unbalanced three-phase type. A scheme of reconfiguring the existing …