126 research outputs found
Jittered uniform sampling - examples
No full textIn many communication systems jitter is a problem causing performance degradation. The jitter is present in both analogue parts and in the sampling process. In this contribution examples of calculated and simulated spectra are shown for uncorrelated Uniform and uncorrelated and correlated Gaussian jitter distributions. Closed form expressions are also given for selected correlated noise cases. In two companion contributions, [1] random input signals and [21 deterministic input signals perturbed by jitter are analysed and the mathematical foundation to the examples given here are made. The analytical results show that the output signal spectrum consists of both discrete and continuous parts. For some applications, such as instruments for spectrum analysis, large jitter can be of great use utilizing the fact that discrete alias components can be completely removed with sufficiently large jitter.</p
Spatial distribution of water level impacting back-barrier bays
No full text© The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Aretxabaleta, A. L., Ganju, N. K., Defne, Z., & Signell, R. P. Spatial distribution of water level impacting back-barrier bays. Natural Hazards and Earth System Sciences, 19(8), (2019): 1823-1838, doi: 10.5194/nhess-19-1823-2019.Water level in semi-enclosed bays, landward of barrier islands, is mainly driven by offshore sea level fluctuations that are modulated by bay geometry and bathymetry, causing spatial variability in the ensuing response (transfer). Local wind setup can have a complementary role that depends on wind speed, fetch, and relative orientation of the wind direction and the bay. Bay area and inlet geometry and bathymetry primarily regulate the magnitude of the transfer between open ocean and bay. Tides and short-period offshore oscillations are more damped in the bays than longer-lasting offshore fluctuations, such as a storm surge and sea level rise. We compare observed and modeled water levels at stations in a mid-Atlantic bay (Barnegat Bay) with offshore water level proxies. Observed water levels in Barnegat Bay are compared and combined with model results from the Coupled Ocean–Atmosphere–Wave–Sediment Transport (COAWST) modeling system to evaluate the spatial structure of the water level transfer. Analytical models based on the dimensional characteristics of the bay are used to combine the observed data and the numerical model results in a physically consistent approach. Model water level transfers match observed values at locations inside the bay in the storm frequency band (transfers ranging from 50 %–100 %) and tidal frequencies (10 %–55 %). The contribution of frequency-dependent local setup caused by wind acting along the bay is also considered. The wind setup effect can be comparable in magnitude to the offshore transfer forcing during intense storms. The approach provides transfer estimates for locations inside the bay where observations were not available, resulting in a complete spatial characterization. An extension of the methodology that takes advantage of the ADCIRC tidal database for the east coast of the United States allows for the expansion of the approach to other bay systems. Detailed spatial estimates of water level transfer can inform decisions on inlet management and contribute to the assessment of current and future flooding hazard in back-barrier bays and along mainland shorelines.This work was supported by the US Geological Survey, Coastal and Marine Hazards/Resources Program
Gender-based differences in learner English : A syntax study of Swedish high school students’ written production
No full textFemale students have long had a perceived advantage over male students in second language ac-quisition. In Swedish schools, the girls have outperformed the boys in the subject of English since the end of the Second World War, but the female students’ edge over the male students has diminished considerably over time. This essay aims to find out if there are any differences in lin-guistic ability between the two genders. The study uses a T-unit based syntax analysis in order to quantify the level of syntactic maturity that Swedish high school students possess, using data drawn from the Uppsala Learner English Corpus. Furthermore, the study aims to research gen-der-based stylistic differences and risk-taking behavior in the student’s writing. The results show that there are differences in syntactic maturity between the genders, as the female students in junior high school and the male students in senior high school outperform their respective counterparts, particularly in the indices based on error-free T-units. In addition, there are also stylistic disparities, as the female students have a greater focus on personalized ac-counts in their writing and the male students in junior high school have a very sparse and concise style of writing. The conclusion is drawn that while there are differences in syntactic maturity between boys and girls, the syntactic indices cannot accurately display the sophistication of the students’ writing and consequently should only be used in conjunction with more qualitative measures. Finally, while the study is not able to discern risk-taking in the students’ writing, the author concludes that risk-taking is an important factor in second language acquisition, especially considering the fact that the Swedish curricula in junior and senior high school English have a strong focus on communicative competence
Nucleon-nucleon theory and phenomenology. Progress report and renewal proposal
No full textProgress is outlined on five inter-related subprojects: (1) derivation of the intermediate range nucleon-nucleon interaction with the new dramatically altered ..pi pi.. s-wave interaction and using a new method that utilizes much shorter and simpler analytic continuation through the unphysical region that lies between the ..pi..N and ..pi pi.. physical regions of the N anti N ..-->.. ..pi pi.. amplitude (with significantly improved accuracy for the nucleon-nucleon interaction); (2) construction of a short range phenomenological potential that, with the theoretical part mentioned above, gives a precise fit to the nucleon-nucleon data and is parameterized for easy use in nucleon calculations; (3) phase shift analyses of the world data below 400 MeV, especially the large amount of very precise data below 20 MeV and the new data near 55 MeV that have never been analyzed properly, and determining which phases are given by theory at which energies; (4) the introduction of our K-matrix formulation of the Optimal Polynomial Expansion in order to accelerate convergence of the partial wave series at LAMPF energies; and (5) setting up of a cooperatively evaluated and verified permanent nucleon-nucleon data bank in the 0 to 1200 MeV range that can be used by all nucleon-nucleon researchers (or anyone else) via Telenet dial-in and by means of a published compendium. (WHK
Antenna configuration method in communication system involves arranging antenna elements in separation that is set in relation to communication distance or communication wavelength
No full textNOVELTY - The method involves configuring several antenna elements by arranging them in a separation that is set in relation to communication distance or communication wavelength. USE - For antenna configuration in high data rate communication system. ADVANTAGE - Increases throughput such as transmission of data at both vertical and horizontal polarizations. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following: (1) antenna configuration; and (2) communication system. DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of the antenna configuration process.</p
- …
