Studies in the history of the song school at Durham from the early fifteenth century to the early eighteenth century

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Multi-Mode Analysis of Dual Ridged Waveguide Systems for Material Characterization

In this dissertation, two nondestructive dual ridged waveguide (DRWG) material characterization systems are investigated. The single and clamped DRWG probe geometries were analyzed in previous work; however, that research only incorporated the dominant DRWG mode. Here, that restriction is removed and the existence of evanescent higher- order modes is considered. Theoretical analysis of the single and clamped DRWG probes is presented and discussed. The approach taken here is similar to that presented in previous research: Love\u27s equivalence theorem is used to remove the DRWG apertures which are replaced with equivalent magnetic currents radiating in the presence of the background parallel-plate waveguide structure. Enforcing the continuity of the tangential magnetic fields in the DRWG and parallel- plate regions yields a system of coupled magnetic field integral equations (MFIEs). This coupled MFIE system is solved using the Method of Moments (MoM) where the tangential electric and magnetic fields in the DRWG are used as expansion and testing functions, respectively. Inversion of the resulting MoM impedance matrix produces theoretical expressions for the reflection and transmission coefficients which are numerically inverted (via nonlinear least squares) to yield estimates of the permittivity and permeability of the material under test. While the steps taken in the theoretical development are similar to previous work, the addition of higher-order modes into the analysis substantially complicates the derivation and is a significant extension of the existing dominant-mode-only literature. Lastly, simulation results of the two structures are presented. A comparison of the dominant-mode only reflection and transmission coefficients with the higher-order mode coefficients is provided

Precovering Dgc-Complexes

In this thesis we prove that with the hypotheses that dg e C is injectively resolving and that the class C is closed under arbitrary direct limits we have that the following are equivalent to dgC being covering: Every complex of C-modules is in dg e C and every exact complex of C-modules is in e C

A CASE STUDY OF NON-NATIVE ENGLISH-SPEAKING INTERNATIONAL UNIVERSITY STUDENTS PARTICIPATING IN A COMMUNITY OF PRACTICE

The social identity construction of international students studying in the United States is important to the field of second language learning and the study of identity. A Social Identity and Communities of Practice (CoP) framework were used to understand how participation in a CoP informed the identity of non-native speaking university international students studying in the U.S. The focus of this study was to investigate how participation in a CoP informed the identity of non-native speaking international university students studying in the U.S. I proposed that these frameworks provided a foundation for understanding how participation in a CoP for non-native English-speaking university students informed their international student identity. Furthermore, this study showed how participation in a CoP contributed to the participants’ sense of belonging. Data collected for this study included audio recordings of the group and individual interviews, notes from the observation of the CoP, audio recordings of the CoP observations, and notes of researcher’s thoughts. Several major themes emerged including: Identity, Language, and Aspects of Communities of Practice. These themes described why this group of students decided to belong to this particular CoP, their motivation for attending and participating in this CoP, and their experiences in the CoP. Results of this study addressed that participating in a CoP helped participants inform their international student identity and a sense of belonging

Fusion of Inertial Sensors and Orthogonal Frequency Division Multiplexed (OFDM) Signals of Opportunity for Unassisted Navigation

The advent of the global positioning system (GPS) has provided worldwide high-accuracy position measurements. However, GPS may be rendered unavailable by jamming, disruption of satellites, or simply by signal shadowing in urban environments. Thus, this thesis considers fusion of Inertial Navigation Systems (INS) and Orthogonal Frequency Division Multiplexed (OFDM) signals of opportunity (SOOP) for navigation. Typical signal of opportunity navigation involves the use of a reference receiver and uses time difference of arrival (TDOA) measurements. However, by exploiting the block structure of OFDM communication signals, the need for the reference receiver is reduced or possibly removed entirely. This research uses a Kalman Filter (KF) to optimally combine INS measurements with the OFDM TDOA measurements. A proof of concept in two dimensions is shown, and effects of the number of transmitters, sampling rate, multipath, and clock errors are investigated

On the structure of right 3-Engel subgroups

AbstractWe state and prove two sharp results on the structure of normal subgroups consisting of right 3-Engel elements. First we prove that if H is a 3-torsion-free such subgroup of a group G and x∈G, then [H,〈x〉G4]={1}. When H is additionally {2,5}-torsion-free, we prove that [H,G8]={1}

SlowFuzz: Automated Domain-Independent Detection of Algorithmic Complexity Vulnerabilities

Algorithmic complexity vulnerabilities occur when the worst-case time/space complexity of an application is significantly higher than the respective average case for particular user-controlled inputs. When such conditions are met, an attacker can launch Denial-of-Service attacks against a vulnerable application by providing inputs that trigger the worst-case behavior. Such attacks have been known to have serious effects on production systems, take down entire websites, or lead to bypasses of Web Application Firewalls. Unfortunately, existing detection mechanisms for algorithmic complexity vulnerabilities are domain-specific and often require significant manual effort. In this paper, we design, implement, and evaluate SlowFuzz, a domain-independent framework for automatically finding algorithmic complexity vulnerabilities. SlowFuzz automatically finds inputs that trigger worst-case algorithmic behavior in the tested binary. SlowFuzz uses resource-usage-guided evolutionary search techniques to automatically find inputs that maximize computational resource utilization for a given application.Comment: ACM CCS '17, October 30-November 3, 2017, Dallas, TX, US

A Comparison of the mammalian and reptilian tecta

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/49930/1/900780303_ftp.pd

Obesity Prevalence and Dietary Intake of Antioxidants in Native American Adolescents

Antioxidants are well known for possessing anti-inflammatory properties, which can reduce the risk of chronic disease and obesity. However, very little research has been done to examine antioxidant intake among adolescent minority populations such as Native American adolescents. Our study examined the significance of antioxidant intake among Native American adolescents at an urban residential high school in Southern California. Our study population consisted of 183 male and female Native American adolescents, 14-18 years of age, representing 43 tribes from across the United States. Students' primary source of meals was provided by the school food service. Based on the BMI calculations, the rate of obesity within our population was 38% for males and 40% for females, more than two-fold the national rate indicated by NHANESIII data. We used the Harvard School of Public Health Youth/Adolescent Questionnaire (HSPH YAQ), a semi-quantitative food frequency questionnaire, to examine antioxidant nutrient intake and evaluate the differences in the intake between normal and obese weight students. Statistical analysis of the results showed that intakes of vitamins C, E, and lycopene were the antioxidant nutrients found to be significantly different between normal and obese weight students and intakes of these nutrients were found to be higher among normal weight students (p-values = 0.02451, 0.00847, and 0.04928, respectively). These results suggest that dietary intake of antioxidants could be increased among Native American adolescents. Further research is needed to confirm our findings and identify effective ways for school food service to incorporate antioxidant rich foods into school menus