Theses and Dissertations
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This collection contains the theses and dissertations approved for public release from Texas A&M University.
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Tabatabaei-Yazdi, Seyed (August 2011)[more][less]
Abstract: In classical network information theory, information packets are treated as commodities, and the nodes of the network are only allowed to duplicate and forward the packets. The new paradigm of network coding, which was introduced by Ahlswede et al., states that if the nodes are permitted to combine the information packets and forward a function of them, the throughput of the network can dramatically increase. In this dissertation we focused on the design and analysis of low complexity network coding schemes for different topologies of wired and wireless networks. In the first part we studied the routing capacity of wired networks. We provided a description of the routing capacity region in terms of a finite set of linear inequalities. We next used this result to study the routing capacity region of undirected ring networks for two multimessage scenarios. Finally, we used new network coding bounds to prove the optimality of routing schemes in these two scenarios. In the second part, we studied node-constrained line and star networks. We derived the multiple multicast capacity region of node-constrained line networks based on a low complexity binary linear coding scheme. For star networks, we examined the multiple unicast problem and offered a linear coding scheme. Then we made a connection between the network coding in a node-constrained star network and the problem of index coding with side information. In the third part, we studied the linear deterministic model of relay networks (LDRN). We focused on a unicast session and derived a simple capacity-achieving transmission scheme. We obtained our scheme by a connection to the submodular flow problem through the application of tools from matroid theory and submodular optimization theory. We also offered polynomial-time algorithms for calculating the capacity of the network and the optimal coding scheme. In the final part, we considered the multicasting problem in an LDRN and proposed a new way to construct a coding scheme. Our construction is based on the notion of flow for a unicast session in the third part of this dissertation. We presented randomized and deterministic polynomial-time versions of our algorithm.
URI: http://hdl.handle.net/1969.1/128797 Files in this item: 1
TABATABAEI-YAZDI-DISSERTATION_rev.pdf (1.193Mb) -
Willis, Janet (December 2011)[more][less]
Abstract: Today's urban schools are composed of students from diverse cultural backgrounds and varying levels of academic readiness. At the same time, approximately 88% of teachers are White and middle-class. The dispositions of teachers have important educational ramifications. Teachers' beliefs structure the classroom atmosphere, influence perceptions regarding the abilities of students, and impact how they teach and expect students to learn and behave. In order to foster an accepting and productive learning environment, teachers must have cultural awareness. To ensure that all learners receive a solid academic foundation, teachers must be able to instruct dissimilar students. Special educators have been trained to work with students with unique, special needs, but the reality of today's demographics - and special education classrooms in particular - mandate that they also have the cultural knowledge to effectively serve diverse students. Perceptions and attitudes of elementary special education teachers regarding their cultural awareness and beliefs need to be explored. This study examined the cultural awareness beliefs of elementary special educators working in urban school districts located in southeast Texas. The research also needs to ascertain whether ethnicity or length of service effected such teachers' cultural awareness beliefs. Using the Cultural Awareness Beliefs Inventory (CABI) instrument, the investigator gathered self-reported data from 54 participants. The reliability and validity of the instrument were determined to be sound by previous investigators. The CABI contains eight major components: Teacher Beliefs, School Climate, Culturally Responsive Classroom Management, Home and Community Support, Curriculum and Instruction, Cultural Sensitivity, Cultural Awareness, and Teacher Efficacy. Data were analyzed using percentage analysis and one-way analysis of variance. The findings include: 1) Participants had favorable perceptions towards the School Climate, Culturally Responsive Classroom Management, and Cultural Awareness variables; 2) Participants had unfavorable perceptions regarding Teacher Beliefs; 3) In contrast to some previous research, it did not appear that teaching experience impacted cultural beliefs; and 4) Importantly, it was discerned that teachers' ethnicities yielded statistically significant effects on their cultural awareness and beliefs regarding African American special education students.
URI: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10710 Files in this item: 1
WILLIS-DISSERTATION.pdf (4.237Mb) -
Banerjee, Sikhar (December 2011)[more][less]
Abstract: The purpose of this study is to identify and analyze the geochemical facies of the Hushpuckney Shale using XRF scanning data and the bioturbation indices, which will contribute to a better understanding of the biogeochemical environment prevalent during the deposition of the Hushpuckney Shale. The Hushpuckney Shale Member of the Swope Formation (Kasimovian Stage) preserved in KGS Spencer core 2 - 6, consists of a black shale submember overlain by bioturbated gray shale. Millimeter-scale core description and analysis of XRF scanning data enables identification of geochemical facies within the study core and contributes to understanding the environment of shale deposition. The XRF spectrometer produces X-ray image of the core and abundance values of selected major and trace elements, including iron (Fe), calcium (Ca), sulfur (S), molybdenum (Mo), zinc (Zn), vanadium (V), chromium (Cr), copper (Cu), nickel (Ni), titanium (Ti), zircon (Zr), potassium (K) and phosphorous (P). Canfield and Thamdrup's (2009) classification of geochemical environments is used to recognize oxic/aerobic, manganous-nitrogenous, ferruginous and sulfidic facies within the black shale submember. A modification of Droser and Bottjer's (1986) semi-quantitative field classification of bioturbation is used to identify facies variations within the gray shale submember. Abundance of apatite nodules and lamina in the black shale submember of the study core suggest that black shale sediments accumulated slowly in a sediment-starved basin. A high abundance of sulfide-scavenged elements, including Mo, Zn, V, Ni and Cr, identifies the sulfidic facies in the black shale submember, and indicates deposition in an oxygen-depleted environment with a high concentration of hydrogen sulfide. The overlying ferruginous facies has lower abundances of sulfide-scavenged elements and lacks cryptic Fe-laminations. The uppermost black shale submember facies, the manganous-nitrogenous facies, has cryptic Fe laminations and a relatively high P/Ca ratio. Abundance of cryptic iron laminations and apatite nodules and lamina indicates the syngenetic deposition of iron and phosphate due to Fe-P coupling mechanism. The gray shale submember is burrowed, indicating deposition under oxygenated conditions. Bioturbation indices reveal the variations in the intensity and nature of burrows within the gray shale, which corresponds to the changes in the depositional environment that may be related to the rise and fall of sea-level.
URI: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10706 Files in this item: 1
BANERJEE-THESIS.pdf (2.011Mb) -
Handy, Justin (December 2011)[more][less]
Abstract: Laboratory methods for studying memory blocking and recovery include directed forgetting, retrieval-induced forgetting, and retrieval bias or memory blocking procedures. These methods primarily use word lists. For example, striking, reversible forgetting effects have been reported for both emotional (e.g., expletives) and non-emotional (e.g., tools) categorized lists of words. The present study examined forgetting and recovery of richer, more episodic materials. Participants studied a series of brief narrative passages varying in emotional intensity, such as a vignette involving torture or child abuse (emotional) vs. vignettes about cycling or insects (non-emotional). Free recall of the 1-word titles of the vignettes (e.g., Torture, Cyclist) showed a strong memory blocking effect, and cues from the stories on a subsequent cued recall test reversed the effect. In a second experiment, vignette-related pictures inserted into an incidental picture naming task triggered some recovery of initially forgotten vignettes, as shown on a post-test. Both emotional and non-emotional stories were susceptible to this reversible memory blocking effect.
URI: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10704 Files in this item: 1
HANDY-THESIS.pdf (1.640Mb) -
Melero, Calixto (December 2011)[more][less]
Abstract: This thesis uses data from The Survey of Texas Adults, 2004 to analyze the giving and volunteering patterns of various groups focusing on the role of several relevant social and demographic characteristics and also focusing on whether or not an individual was asked to participate in these various activities. Multivariate logistic regression analysis is performed to test for statistical relationships between selected factors and giving and volunteering rates. In each of the analysis, logistic regression models are estimated to assess how factors such as race, education, citizenship, gender, age, income, and being asked affect the outcomes of money given to religious organizations, money given to other organizations, being asked to volunteer, and solicited for money. Findings suggest that, overall, Latinos are not significantly different in their odds of giving to religious organizations when compared to their white counterparts. The results of the next set of logistic models, however, show that Latinos have lower odds of giving to other groups or organizations. In terms of who is asked to volunteer or solicited for money, the results suggest that Latinos are not asked to volunteer at the same rate as whites; therefore, limiting an important avenue of participation. These finding confirm the hypothesis that Latinos are just as likely to make financial contributions to their local church, but they have lower odds of giving to other, nonreligious organizations. In addition, the findings confirm that Latinos are less likely to be asked to volunteer when compared to other groups.
URI: http://hdl.handle.net/1969.1/ETD-TAMU-2011-12-10696 Files in this item: 1
MELERO-THESIS.pdf (800.1Kb)
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