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Impact of MIMO Transmission on CAF-Based GeolocationOverfield, Jacob Ivan 27 August 2013 (has links)
The Cross Ambiguity Function (CAF) is often used for passive geolocation of an emitter based on the time difference of arrival (TDOA) and frequency difference of arrival (FDOA) of the received signals. CAF performance has been thoroughly investigated in regards to traditional single-input single-output (SISO) signals. Little is known about how the CAF will respond to signals from multiple-input multiple-output (MIMO) systems which utilize multiple antennas. This thesis focuses on characterizing the CAF's magnitude distribution in order to determine the probability of correctly determining the correct TDOA/FDOA bin, and the resulting impact on geolocation. The received signals are studied in the presence of additive white Gaussian noise (AWGN) as well as multi-channel propagation effects such as phase ambiguities and offsets due to multi-antenna transmission.
Two and four transmit antennas using either a form of spatial multiplexing or space-time block coding are the focus of this work because they are mostly commonly found in currently deployed communication systems. The effects of these transmit schemes are studied with respect to TDOA/FDOA error and the resulting position error. The analysis is performed using a detection theory framework as opposed to estimation theory in order to empha- size the impact of MIMO transmission on determining the correct TDOA/FDOA bin. A simple method using the CAF magnitude as a decision statistic is also presented so that TDOA/FDOA errors can be detected and filtered in an attempt to improve positioning estimates. / Master of Science
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Perceptions of boundary ambiguity and parentification effects on family satisfaction, family support, and perceived stress in young adults of divorced familiesAndsager, Kaylee January 1900 (has links)
Master of Science / School of Family Studies and Human Services / Amber Vennum / Using a sample of 109 students at a Midwestern university with divorced or separated parents I explored a) how sibling order and young adults’ age at parental divorce or separation impacted their experience of boundary ambiguity, parentification, stress, and family satisfaction and support, b) whether parentification mediated the effects of boundary ambiguity on stress, family support and family satisfaction, and c) whether sibling order moderated the relationship between these variables. I found that the child’s age at parental divorce/separation was positively correlated with boundary ambiguity, and negatively correlated with parentification, stress, family satisfaction, and social support. First or only children reported higher rates of parentification, specifically taking on a spousal role with their parents than younger siblings. Further, in divorced/separated families boundary ambiguity was positively related to young adults’ stress and negatively related to their levels of family satisfaction and family support both directly and indirectly through parentification. However, sibling order was not found to moderate the relationships between boundary ambiguity, parentification, family support, family satisfaction, and stress. Implications for theory and intervention are discussed.
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An investigation into the relationship between tolerance of ambiguity and creativity among military officersMcClary, Rob B. January 1900 (has links)
Doctor of Philosophy / Department of Educational Leadership / Sarah Jane Fishback / This study investigated the relationship between the tolerance of ambiguity (AT) levels of the officers attending the U.S. Army’s School of Advanced Military Studies (SAMS) and the creativity of the military plans they developed. Located aboard Fort Leavenworth, KS, SAMS is an Army school providing education to specially selected officers in preparation for duties in positions as battalion commanders and lead planners for Army divisions and corps. The officers at SAMS are grouped into seminars for their classes, and they remain with their seminars throughout the yearlong educational program.
The twin purposes of this study were to (a) test for the relationship between AT and creativity suggested by various theories of creativity and (b) contribute to the Army’s efforts to increase the creativity of its officers by empirically identifying the expected positive correlation between the officers AT levels and the creativity of their plans. A sample of 66 officers participated in the study. They each independently developed a military plan in response to a common notional scenario. Subsequently they each independently completed the short version of Norton’s (1975) MAT-50 to measure their levels of AT. Their plans were assessed for creativity using Amabile’s Consensual Assessment Technique (CAT). The high inter-rater reliability among the judges (r = .82) demonstrated the effectiveness of the CAT as a method for assessing the creativity of military plans.
Counter to the expectation, analysis of the data revealed a small negative correlation throughout the sample between AT scores and the creativity of the plans, producing a disconfirmation dilemma for the researcher. Analysis revealed that the sample’s collective levels of AT differed among the various subscales of the MAT-50. Additionally, post hoc analysis
revealed statistically significant variance of the creativity of the officers’ plans between the different seminars to which they were assigned. In the seminar with the highest creativity scores, there was a small positive correlation between AT and creativity, while in the seminar with the lowest creativity scores, there was a medium sized negative correlation between the two variables. Implications of these findings and recommendations for future research are discussed.
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Relative-fuzzy : a novel approach for handling complex ambiguity for software engineering of data mining modelsImam, Ayad Tareq January 2010 (has links)
There are two main defined classes of uncertainty namely: fuzziness and ambiguity, where ambiguity is ‘one-to-many’ relationship between syntax and semantic of a proposition. This definition seems that it ignores ‘many-to-many’ relationship ambiguity type of uncertainty. In this thesis, we shall use complex-uncertainty to term many-to-many relationship ambiguity type of uncertainty. This research proposes a new approach for handling the complex ambiguity type of uncertainty that may exist in data, for software engineering of predictive Data Mining (DM) classification models. The proposed approach is based on Relative-Fuzzy Logic (RFL), a novel type of fuzzy logic. RFL defines a new formulation of the problem of ambiguity type of uncertainty in terms of States Of Proposition (SOP). RFL describes its membership (semantic) value by using the new definition of Domain of Proposition (DOP), which is based on the relativity principle as defined by possible-worlds logic. To achieve the goal of proposing RFL, a question is needed to be answered, which is: how these two approaches; i.e. fuzzy logic and possible-world, can be mixed to produce a new membership value set (and later logic) that able to handle fuzziness and multiple viewpoints at the same time? Achieving such goal comes via providing possible world logic the ability to quantifying multiple viewpoints and also model fuzziness in each of these multiple viewpoints and expressing that in a new set of membership value. Furthermore, a new architecture of Hierarchical Neural Network (HNN) called ML/RFL-Based Net has been developed in this research, along with a new learning algorithm and new recalling algorithm. The architecture, learning algorithm and recalling algorithm of ML/RFL-Based Net follow the principles of RFL. This new type of HNN is considered to be a RFL computation machine. The ability of the Relative Fuzzy-based DM prediction model to tackle the problem of complex ambiguity type of uncertainty has been tested. Special-purpose Integrated Development Environment (IDE) software, which generates a DM prediction model for speech recognition, has been developed in this research too, which is called RFL4ASR. This special purpose IDE is an extension of the definition of the traditional IDE. Using multiple sets of TIMIT speech data, the prediction model of type ML/RFL-Based Net has classification accuracy of 69.2308%. This accuracy is higher than the best achievements of WEKA data mining machines given the same speech data.
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Ambiguity aversion and the stock market participation : empirical evidenceZhang, Ruo Gu January 2015 (has links)
Theoretical models predict that ambiguity is an asset pricing factor in addition to risk, however few of them have been tested in the real market. This thesis tests one of the hypotheses that, investors’ propensity to invest in stocks is reduced when ambiguity in the marketplace increases. The hypothesis is tested by using equity fund flows and households’ equity holding as measurements of the market participation, and using dispersion in analysts’ forecasts about aggregate returns as measurement of ambiguity. The results confirm this hypothesis, since the increases in ambiguity are significantly and negatively related to equity fund flows, as well as the likelihood that the average household invests in equities. Moreover, the results also find that the fund flows in non-dividend paying stocks are more sensitive to the changes in ambiguity, and investors transfer capital from the equity market into more liquid asset classes during high-ambiguity periods. In addition, this thesis also tests whether there is heterogeneity in individuals’ ambiguity aversion, and examines the psychological roots of ambiguity aversion. FNE theory explains ambiguity aversion as the result of fearing negative evaluation from others. It predicts that married households are more ambiguity averse; while households with higher income and education, or households that are more mature, are less ambiguity averse. On the other hand, self-evaluation theory explains ambiguity aversion as the result of minimizing anticipated regret. It predicts that households that are more optimistic, or have less income, are less ambiguity averse; while households that have negative market experience, or have higher income, are more ambiguity averse. The results show that married households, or households with high income / negative market experience, are more ambiguity averse; and households that are more optimistic / more mature, are less ambiguity averse. Therefore, both theories have successful predictions, suggesting that the ambiguity aversion is the combined result of the two motivations.
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Communicating Romantic Intentions through Social DancingDuvall, Tracy January 1996 (has links)
This is an analysis of how young Latino men and their female dance partners
communicate their romantic intentions while dancing, or perhaps through dancing. I find that apparent ethnic and class distinctions
and levels of romantic interest affect the way these people dance, especially in three key indices of romantic intentions: eye contact, hand placement, and hip position. Because these intentions are culturally unspeakable in this context, talk is important mostly for its non-referential
effects.
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Ambiguity and Alignment in Academic Policies: Course Substitutions, Learning Disabilities, and Universal DesignGalilee-Belfer, Mika January 2012 (has links)
While research on barriers to full participation for those with learning and other disabilities has focused largely on structural and institutional obstacles to work and education (Swain, French, & Cameron, 2005; Jones, 1996; Watson, 2002), the recognition of disability as a social justice issue is gaining currency (Kraus, 2008). Expensive, bureaucratic, and protracted procedures for reasonable accommodations for students with disabilities in colleges and universities may serve as institutional obstacles that can challenge notions of social justice. This study examined academic policy implementation surrounding foreign language substitution procedures and practices in five institutions of higher education. Nineteen academic administrators were interviewed to examine how and when policies are implemented, and how those responsible for decision-making around student requests for foreign language substitutions as a reasonable accommodation approach their decision-making. Additionally, content analysis of institutional material listed on websites and in documents available to students was conducted to understand in what model(s) of disability substitution requests are rooted. Finally, four students from one of the five institutions were interviewed to contextualize the findings from the institutional administrator interviews and content analysis. The framework of Strategic Ambiguity is utilized to examine how ambiguity in policy creation and implementation can negatively impact the experiences of some students with disabilities in higher education, even as it benefits administrators who can capitalize on ambiguity to align their policy decisions with individual interpretations of fairness. The framework of Universal Design is utilized to examine how diverse perspectives on the comparative importance of language and cultural study may legitimize the expansion of curricular options for all students.
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Conditions on the existence of unambiguous morphismsNevisi, Hossein January 2012 (has links)
A morphism $\sigma$ is \emph{(strongly) unambiguous} with respect to a word $\alpha$ if there is no other morphism $\tau$ that maps $\alpha$ to the same image as $\sigma$. Moreover, $\sigma$ is said to be \emph{weakly unambiguous} with respect to a word $\alpha$ if $\sigma$ is the only \emph{nonerasing} morphism that can map $\alpha$ to $\sigma(\alpha)$, i.\,e., there does not exist any other nonerasing morphism $\tau$ satisfying $\tau(\alpha) = \sigma(\alpha)$. In the first main part of the present thesis, we wish to characterise those words with respect to which there exists a weakly unambiguous \emph{length-increasing} morphism that maps a word to an image that is strictly longer than the word. Our main result is a compact characterisation that holds for all morphisms with ternary or larger target alphabets. We also comprehensively describe those words that have a weakly unambiguous length-increasing morphism with a unary target alphabet, but we have to leave the problem open for binary alphabets, where we can merely give some non-characteristic conditions. \par The second main part of the present thesis studies the question of whether, for any given word, there exists a strongly unambiguous \emph{1-uniform} morphism, i.\,e., a morphism that maps every letter in the word to an image of length $1$. This problem shows some connections to previous research on \emph{fixed points} of nontrivial morphisms, i.\,e., those words $\alpha$ for which there is a morphism $\phi$ satisfying $\phi(\alpha) = \alpha$ and, for a symbol $x$ in $\alpha$, $\phi(x) \neq x$. Therefore, we can expand our examination of the existence of unambiguous morphisms to a discussion of the question of whether we can reduce the number of different symbols in a word that is not a fixed point such that the resulting word is again not a fixed point. This problem is quite similar to the setting of Billaud's Conjecture, the correctness of which we prove for a special case.
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Some Effects of Social Satiation and Visual Ambiguity upon Retardates and NormalsDye, Murlon H. (Murlon Herbert) 08 1900 (has links)
The purpose of this research has been to investigate the ability of subjects of three mental ability levels—normal, educable retardates, and trainable retardates—to recognize and identify familiar visual images projected in a manner assuring standard degrees of ambiguity of the projected images under the conditions of social satiation and non-satiation.
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Empirical Characterization of Variability Among Affymetrix Probe Set Expression Summaries by Sequence FidelityKliner, Shelbie B 01 January 2006 (has links)
Microarray technology provides a quantitative assessment of the number of gene transcripts gene using a high-throughput hybridization assay. Reliable detection of gene expression therefore requires reliable design of probes used in the hybridization assay. It is noted that microarray gene expression measurements are often characterized by variability, even among a series of technical replicate arrays. Therefore, sequence verification, used as a low-level filter to exclude probes exhibiting sequence inaccuracies, has previously been shown to reduce gene expression variability.Building on this work, the effects of sequence- and annotation-based filtering methods were quantified, and shown to be effective in reducing microarray variability among a set of technical replicates. Further, appropriate thresholds for filtering are recommended. A significant interaction in an analysis of variation model was found when a combination of sequence- and annotation-based filtering methods were explanatory factors, suggesting the use of the combination of filtering methods might be most beneficial.
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