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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Subdiffusion through Switching

January 2019 (has links)
archives@tulane.edu / An ongoing effort in the study of microparticle movement in biofluids is the proper characterization of subdiffusive processes i.e. processes whose mean-squared displacement scales as a sublinear power law. In order to describe phenomena that lead to subdiffusive behavior, a few models have been developed: fractional Brownian motion, the generalized Langevin equation, and random walks with dependent increments. We will present perhaps a simpler model that leads to subdiffusion and is designed to characterize systems where a regularly diffusive particle intermittently becomes trapped for long periods of time. By combining ideas from Hybrid Switching Diffusion and queuing systems literature we will describe the law of our process. The major obstacle is the introduction of heavy tail immobilization times and we will overcome it by representing the power law as an infinite mixture of exponentials. The description of the law allows us also to solve the First Passage Problem. Modeling subdiffusion is a very active field of research both in mathematics and physics. Physicists often use a continuous model that originates in the theory of random walks - Brownian motion inversely subordinated to an $\alpha$-stable process. In a similar way we will describe our process. With this description we will show that our process under rescaling is equivalent to the inverse subordinated Brownian motion, i.e., we will present the functional limit theorem for Switching Diffusion. / 1 / Lukasz Sikora
2

A DYNAMIC SELECT SECTOR SPDRS ETFS PORTFOLIO OPTIMIZATION MODEL WITH REGIME-SWITCHING ECONOMIC INDICATORS

Chang, Jingzhi 12 December 2013 (has links)
This thesis studies a dynamic Select Sector SPDRs ETFs portfolio optimization problem. The objective of the optimization model is to maximize the risk-adjusted expected return of a portfolio similar to a logarithmic utility maximization. The conditional value-at-risk measure is chosen to be an additional risk exposure constraint. The vector auto-regression (1) regime-switching economic factor model estimated with the expectation-maximization algorithm is employed to identify different market regimes over time. The expected ETFs returns and their variance-covariance matrix used in the objective function of the optimization model are generated by a regime-switching asset pricing model. Both regime-switching models have proven to be superior to respective single-regime models due to their greater predictive ability. The optimized portfolio performance evaluated by Sharpe ratio, Treynor ratio and Jensen’s alpha are all statistically significant compared to those of the equally weighted ETFs portfolio and S&P 500 stock index. This illustrates that incorporating the regime-switching technique, the portfolio optimization model is effective and successful under both bull and bear market conditions.
3

Switching circuits as information networks

Matheson, William Stephen January 1970 (has links)
A single-output combinational switching network has a number of input terminals, each carrying a signal variable which may take one of two values, and an output terminal, the signal variable of which has a value determined ideally by the input signals only. In this thesis, we make an arbitrary assignment of probabilities to each of the possible configurations of input signal values, (namely that each configuration is equally likely). This is an interpretation of switching variables as random variables with known statistics. We can therefore define and compute the joint source entropy of sets of variables, including the output variable. We use these information quantities, or entropies, to classify switching functions into Equivalence Classes under Permutation and Complementation of input variables, and Negation of the Function. The entropies can also be used to predict some of the useful properties of switching functions, in some cases more simply than conventional methods which employ Boolean Algebra. The model also suggests a switching circuit design philosophy based on the idea of using circuit elements, or gates, to pass information in the input signals which is relevant to the output, while blocking the irrelevant information. Several algorithms are described, and their performance on the design of circuits with small numbers of variables is encouraging. The design philosophy seems particularly able to handle topological constraints, of the type becoming significant in modern switching circuit design. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate
4

Practical Decom List Switching

Devlin, Steve 10 1900 (has links)
International Telemetering Conference Proceedings / October 17-20, 1988 / Riviera Hotel, Las Vegas, Nevada / With more complex vehicle designs, the frequency and number of measurements contained in telemetry data streams has dramatically increased. One way of improving the use of bandwidth is to change the sample rate, quantity, or type of measurements dynamically. A telemetry front end must be programmable to handle different formats. In a front end that decommutates and routes measurements, a decom list is a control program, which defines the location, size, orientation, and identity of the measurements. To deal with dynamic format changes, a telemetry front end must be able to switch between decom lists. A practical approach to decom list switching must address the needs of error avoidance, packet switching, and the location of switching keys in any portion of the format. Switching between formats should not be restricted to a preprogrammed sequence, but should allow multiple destinations from a particular decom list. A practical and flexible implementation of decom list switching is detailed along with an explanation of how this implementation solves a variety of decommutation problems.
5

Numerical investigation of novel structures of nonlinear optical fibre loop mirrors including Bragg gratings

Hemingway, John-Paul J. January 1999 (has links)
No description available.
6

Diglossia and code switching at Mokopane

Matji, Raisibe Patricia January 2010 (has links)
Thesis (M.A (Translation studies and linguistics )) --University of Limpopo (Turfloop Campus), 2010. / This research is intended as a tool to survey the state of Sindebele, the speech variety that is predominantly spoken at Mokopane in the Limpopo Province of South Africa. The study will inform the reader, making use of a sociolinguistic approach, about the language situation at Mokopane. The study further provides a factual account as to what is happening at Mokopane concerning the two commonly spoken speech forms, that is, Sepedi and Sindebele. Furthermore, it presents ideas and insights in order to stimulate academic debates on the differences between isiNdebele and Sindebele and how the authorities are approaching the whole idea of Sindebele as a minority language. The researcher used the qualitative method to have more insight into the language situation of the area. The tool the researcher will use in this research will be the structured interview that will enable her to obtain the required sample of the respondents. The main aim of the researcher to conduct this research is to analyse the linguistic situation to understand the socio-political situation of the area. The researcher has found that the issue of Sindebele is more of a political nature than social. The Sindebele speakers’ concern about the revival of their speech form seems to have gone in one ear and out the other, as a result, Sindebele may totally not be given recognition as a subject in schools. Finally, the researcher gives general recommendations for improving the status of Sindebele.
7

The use of code-switching from Xitsonga to English as a conversational strategy

Baloyi, Hlamalani Dollence January 2010 (has links)
Thesis (M.A. (Translation studies and linguistics)) --University of Limpopo (Turfloop Campus), 2010 / The researcher was motivated to conduct this research because there is a prevalence (high rate) use of code-switching among high school learners, teachers and students in tertiary institutions as well as in Xitsonga texts. This was observed by evaluating selected Xitsonga literature or text books with the aim of investigating why characters in the text books use code-switching as a conversational strategy. Based on the research findings, it became evident that characters/speakers switch because they have a lack of language proficiency, in their language or the target language. Their switch appears to be influenced by their statuses, the lack of equivalent words, the situations they find themselves in and the urge to be socially accepted by their peers. It is recommended that speakers need to learn their language adequately in order to communicate effectively without having to switch
8

Code-switching in Hong Kong

Reynolds Lo, Kuk-chuen, Sabrina., 盧菊存. January 1985 (has links)
published_or_final_version / Language Studies / Master / Master of Arts
9

Optical switching and its application in Sonet-based transmission systems /

Tohme, Philip Edward. January 1991 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 116-126). Also available via the Internet.
10

Frequency and characteristics of code switching in Hispanic bilingual preschool age children of Ohio and California a comparative study /

Coria-Navia, Anneris Bibiana. January 2010 (has links)
Title from first page of PDF document. Includes bibliographical references (p. 51-54).

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