This thesis is a study of the validity and application of the on-shell recursion relations within the theory of General Relativity. These relations are also known as the Britto-Cachazo-Feng-Witten (BCFW) relations. They reduce the calculation of a tree-level graviton scattering amplitude into the evaluation of two smaller physical amplitudes and of a propagator. With multiple applications of the recursion relations, amplitudes can be uniquely constructed from fundamental three-graviton amplitudes. The BCFW prescriptions were first applied to gauge theory. We thus provide a self-contained description of their usage in this context. We then generalize the proof of their validity to include gravity. The BCFW recursion relations can then be used to reconstruct the full theory from cubic vertices. We finally describe how these three-graviton vertices can be determined uniquely from Poincare symmetries.

In the current transmission system, the information bandwidth of the optical fiber communication system is limited by optical amplifier bandwidth, and more efficient use of bandwidth is a very important issue. Amplitude and phase shift keying (APSK) is an advanced modulation scheme to improve the spectral efficiency and can effectively increase the transmission capacity. Certainly, APSK format has a good potential for development. This master thesis is focusing on that to study the transmission performance of the APSK format using digital coherent receiver. As the extinction ratio (ER) of the amplitude shift keying (ASK) signal affects the performances of the ASK signal and phase shift keying (PSK) signal simultaneously, the effect of the ER on the APSK transmission performance was studied. The APSK format has the trade-off between the performances of both the ASK signal and the PSK signal through the ER of the ASK signal. To overcome this issue, a method named zero-nulling method had been proposed, and this method solved the trade-off issue properly. At first, the amendment is to modify the digital coherent receiver program, confirmed that the digital coherent receiver program can correctly resolve APSK signal. Second, in this master thesis, I set up a 500km long optical fiber to measure the transmission performance under APSK format, and try to use recirculating loop system to further increase the transmission distance to several thousand kilometers. Finally, by further modify the receiver program to achieve APSK modulation of the zero-nulling method, and can prove its feasibility.

Mechanical energy exists all over the place in our living, and vibration is the most common way of mechanical performance. Micro-electromechanical systems, the application which integrate techniques and combine different field of research, make it possible to convert vibration into electrical energy by using piezoelectric materials; moreover, it become a small piezoelectric power generator. The thesis set up an equivalent circuit model based on the principle of piezoelectric and cantilever mechanics for experimenting the model¡¦s exactness; consequently, model shows that resonant frequency has no effect on generate electricity when amplitude was fixed. The thesis attempts to change the shape of unimorph for enhancing its power generation. By using different sharp of unimorph, the experiment demonstrate that power generation have direct ratio with frequency at amplitude of 5mm. Moreover, different shapes of the unimorph at frequency of 16Hz have different power output; the disparity among power output might up to 1.78 times.

According to the fast development of portable electronic devices, their characteristics are inclined to miniature profile and lightweight. Nowadays, the wafer-level package (WLP) has been widely applied in portable electronic devices for its miniature profile and lightweight. It will become the mainstream trend later soon. The normal use of portable electronic devices brings low-frequency random vibrations to the electronic packages inside. Because of the increasing demand of these devices, the reliability of electronic packages subjected to repeated mechanical loads has become an important issue in the contemporary electronic packaging industry. In this paper both numerical and experimental studies were carried out to investigate the reliability life of Ultra-CSP under cyclic bending conditions. We perform four-point cyclic bending with various combinations of amplitudes and frequencies. Then, we do failure analysis in Ultra-CSP by observing the failure modes. A finite element model for the package is built up for dynamic as well as quasi-static analyses. Accumulated plastic work per bending cycle within the critical solder ball were calculated and together with the experimental results the parameters for the Coffin-Manson fatigue equation were fitted. Through finite element analysis we find that the solder ball which located in the corner has higher accumulated plastic work. Therefore, the crack in the solder ball grew more easily. Thus it lets package resistance rise to determine failure. It was observed from the bending experiments that the influence of frequencies on the fatigue life of the solder interconnects is inapparent. However, influence of amplitude is significant. From the results of both experiments and FEA, it was found that for this particular ultra-CSP specimen under cyclic bending conditions, the characteristic life was expressed as

Researchers previously have found a correlation between the strength of the auditory steady-state response (ASSR) and corresponding auditory behavioral measurements such as speech recognition scores, thus concluding that the ASSR can be used as an objective measurement of auditory supra-threshold properties. In the present study, it was hypothesized that the increase in the strength of the ASSR at different modulation depths would be reflected in corresponding psychophysical measures, specifically, auditory modulation discrimination. These relationships were investigated in normally-hearing listeners at modulation rates of 40 and 80 Hz for both amplitude (AM) and mixed modulation (MM), at several modulation depths. Analyses were completed for two sets of measurements derived from the physiological and behavioral responses. For the first analysis, derived measures of iso-neurometric thresholds were compared to isometric modulation discrimination thresholds. For the second analysis, derived estimates of physiological neurometric slope were compared to estimated psychometric function slopes. Mixed-model analyses for both of these measures revealed significant or near-significant relationships between physiological and psychophysical measures at 40 Hz for AM and at 80 Hz for MM. Bootstrap resampling analyses were completed to estimate the distribution of the resultant statistics. Implications regarding the location of neural encoding for amplitude and frequency modulation were discussed. / text

The delayed occurrence of fatigue while maintaining submaximal force output is a function that could be driven by the central nervous system (CNS). It has been found previously that mean EMG amplitude increases with fatigue. Endurance time has also been found to increase over repeated testing. The purpose of this study was to compare the muscle activation patterns and endurance times after training of the AdP muscle. This study analyzed surface EMG of the adductor pollicis (AdP) muscle in young, healthy adults during a sustained submaximal isometric fatiguing contraction before and after 4 weeks of muscular endurance task training. Eight participants (training group: n = 4 and control group: n = 4) carried out maximal voluntary contractions (MVCs) while sustaining isometric force of 20% MVC of thumb adduction before and after the four weeks of endurance training. EMG, recorded through surface electrodes, was measured before and after training in an effort to detect a possible CNS training effect. The endurance training group trained the AdP muscle at 20% MVC every other day for 4 weeks. Average force was calculated over 5 second time bins every 5% of endurance time (20 time bins total). A significant increase in endurance time was seen in the training group of this study. A significant effect of change for pre and post-training mean EMG amplitude across the two groups was found (p < .001). A significant interaction effect between pre and post training and control groups was also found (p = .016). There was also a significant deficit in increases of mean amplitude between the first and last time bins of the endurance task (pre and post) after training. This indicates that there is an effect of training on increasing endurance time which can be exhibited through changes in mean EMG amplitude. / text

published_or_final_version / Chemistry / Master / Master of Philosophy

This dissertation presents the results of a study conducted on the speech of male and female students training to become Drill Instructors (hereafter DIs) in the United States Marine Corps. Both high amplitude and low pitch are reported to be important characteristics of the DI Command Voice; these characteristics are also strongly associated with masculinity (Hicks 1997). However, previous research argues that female DIs do not view these qualities as the most important characteristics of the Command Voice. They focus instead on being "direct" (Hicks 1997, Hicks Kennard 1999). The question I address is whether or not the Command Voice taught in DI School is used differently by female and male DI students in authoritative speech.The data were recorded at the DI School in Parris Island, South Carolina. Six subjects participated in the study. The two factors considered were sex and speech style, which included: 1) teachback: high-amplitude recitations of training procedures, 2) locker-box discussion: a speech style used in academic settings, 3) interviews, and 4) a reading sample. Both vowel duration and peak pitch measurements were done in each speech style; measurements on larger thirty-second "chunks" of discourse were taken for mean pitch, standard deviation of pitch, range of pitch, and speaking rate for each speaker in each speech style. There was a significant main effect on vowel duration for all subjects except for one male and a significant main effect on peak pitch for all subjects. For discourse measurements of pitch, there was a significant main effect for mean pitch, standard deviation of pitch, and pitch range.Pair-wise comparisons resulted in significant differences in peak pitch for all subjects in all speech styles. Both females and males exhibited the same pattern for both vowel and discourse pitch measurements, from highest to lowest pitch: teachbacks, lockerbox discussion, reading sample, and interview. However, females' vowels were significantly longer in the most authoritative speech style--precisely where males had their shortest vowel duration. This difference suggests that in authoritative speech, females use vowel duration as part of the "directness" in authority, where males do not.

Proper and precise interpretation of radio occultation soundings of planetary atmospheres requires understanding the signal amplitude and phase variations caused by random perturbations in the complex index of refraction caused by atmospheric turbulence. This research focuses on understanding the turbulence and its impact on these soundings.From aircraft temperature, pressure and humidity measurements we obtained a parametric model for estimating the strength of the atmospheric turbulence in the troposphere. We used high-resolution balloon measurements to understand the spatial spectrum of turbulence in the vertical dimension.We also review and extend electromagnetic scintillation theory to include a complex index of refraction of the propagating medium. In contrast to when the fluctuations in only the real component of the index of refraction are considered, this work quantifies how atmospheric turbulent eddies contribute to the signal amplitude and phase fluctuations and the amplitude frequency correlation function when the index of refraction is complex. The generalized expressions developed for determining the signal's amplitude and phase fluctuations can be solved for planar, spherical or beam electromagnetic wave propagation.We then apply our mathematical model to the case of a plane wave propagating through a homogenous turbulence medium and estimate the amplitude variance for signals at various frequencies near the 22 GHz and 183 GHz water vapor absorption features. The theoretical results predict the impact of random fluctuations in the absorption coefficient along the signal propagation path on the signal's amplitude fluctuations. These results indicate that amplitude fluctuations arising from perturbations of the absorption field can be comparable to those when the medium has a purely real index of refraction. This clearly indicates that the differential optical depth approach devised by Kursinski et al. (2002) to ratio out the effects of turbulence on signals passing through a medium of a purely real index of refraction must be modified to include the effects of turbulent variations in the imaginary part of the refractivity.

The purpose of this study was to investigate the influence of amplitude scaling on bimanual coordination in a circle drawing task. Eleven right-handed subjects traced the perimeter of 5 circles measuring 3, 6, 9, 12, and 15 cm in diameter under the following coordination conditions: (1) both hands move inward together (symmetric coordination pattern), and (2) both hands move counterclockwise together (asymmetric coordination pattern). In a set of self-paced trials, subjects traced each circle separately at a preferred frequency and separately for each coordination pattern. Although subjects matched the required amplitude of the target circles quite well, radial amplitude variability increased with increasing circle diameter. No transitions or movement reversals were observed in the self-paced trials, and the symmetric pattern was more stable than the asymmetric pattern. In a set of amplitude scaling trials, subjects continuously traced the 5 circles from small (3 cm) to big (15 cm) (SB) and from big to small (BS) at two fixed pacing frequencies (1.25 Hz and 1.5 Hz). Observed cycling frequency decreased with increasing circle diameter, and observed radial amplitude was most accurate when tracing the 9 cm diameter circle, with larger than required amplitude when tracing the 3 cm and 6 cm diameter circles, and smaller than required amplitude when tracing the 12 cm and 15 cm diameter circles. Radial amplitude variability also increased with increasing circle diameter in the amplitude scaling trials. The symmetric coordination pattern was more stable than the symmetric coordination pattern. Transitions from the asymmetric to symmetric coordination pattern as well as movement reversals were observed in both scaling directions. No transitions occurred while producing the symmetric pattern in any scaling direction or pacing frequency condition. The results show that amplitude scaling influenced the spatiotemporal aspects of bimanual circle drawing. Moreover, amplitude scaling induced more transitions than previous research that scaled movement frequency as a control parameter in bimanual circle drawing tasks.