The single hydrophone localization problem is considered. Single hydrophone localization is a special case of matched field localization where measurements from only one hydrophone are available. The time series of the pressure at the hydrophone is compared with predicted times series calculated using an ocean acoustic propagation model for many different source locations. The source location that gives the best match between the predicted time series and the measurement is assumed to be the correct source location. Single hydrophone localization algorithms from the literature are reviewed and a new algorithm is introduced. The new algorithm does not require knowledge of the source signal and does not assume the use of a particular ocean acoustic model, unlike some algorithms in the literature. Source location estimates calculated from the new algorithm are compared with ground truth using simulated ocean acoustic measurements and experimental measurements. Source location estimates calculated using other algorithms from the literature are shown for comparison. The simulated measurements use three source signals with bandwidths of 10 Hz, 100 Hz, and 200 Hz and the ocean is modeled as a Pekeris waveguide. The new algorithm estimates the source location accurately for all three source signals when several of the localization algorithms from the literature give inaccurate estimates. Gaussian white noise signals are added to the measured signals to test the impact of signal-to-noise ratio (SNR) on the algorithm. Four signal-to-noise ratios of 60 dB, 40 dB, 20 dB, and 0 dB are used. The new algorithm gives accurate source location estimates down to an SNR of 20 dB for two of the source signal bandwidths. Source location estimates using other algorithms from the literature break down at either 20 dB or 0 dB. Source location estimates are calculated using two hydrophone measurements taken at different depths in an experiment conducted near the Bahamas. The new algorithm accurately estimates the source location in both cases. In one case, only two other localization algorithms from the literature locate the source accurately. In the other case, only one other localization algorithm succeeds.

This thesis performs a quantitative study, derived from the Neyman-Pearson framework, on the robustness of the matched filter detector corrupted by zero mean, independent and identically distributed white Gaussian noise. The variance of the noise is assumed to be imperfectly known, but some knowledge about a nominal value is presumed. We utilized slope as a unit to quantify the robustness for different signal strengths, nominals, and sample sizes. Following to this, a weighting method is applied to the slope range of interest, the so called tolerable range, as to analyze the likelihood of these extreme slopes to occur. A ratio of the first and last quarter section of the tolerable range have been taken in order to obtain the likelihood ratio for the low slopes to occur. We finalized our analysis by developing a method that quantifies confidence as a measure of robustness. Both weighted and non-weighted procedures were applied over the tolerable range, where the weighted procedure puts greater emphasis on values near the nominal. The quantitative analysis results show the detector to be non-robust and deliver poor performance for low signal-to-noise ratios. For moderate signal strengths, the detector performs rather well if the nominal and sample size are chosen wisely. The detector has great performance and robustness for high signal-to-noise ratios. This even remains true when only a few samples are taken or when the practitioner is uncertain about the nominal chosen.

Recent government regulations for Enhanced 911 locating of wireless handsets require accuracy to within 50 and 300 meters. Two technologies under consideration are triangulation using existing wireless base stations and location using global positioning satellites (GPS). Satellite positioning is the leading candidate, however, reception of GPS signals within large buildings is difficult and considerable research is devoted to this topic. Conventional GPS receivers require line of sight to at least four satellites and, under outdoor conditions, the expected signal level is about -160 dBW. Within large buildings, detection is very difficult because there is high thermal noise and some satellite signals can be attenuated to less than -185 dBW while others can suffer little attenuation. In order to construct the pseudo-ranges necessary for position finding, the receiver must synchronize to the incoming codephase of each satellite and must operate with substantial Doppler frequency offset caused by satellite motion.<p> This thesis investigates the application of a parallel non-coherent spread spectrum synchronizer previously implemented as a very-large-scale integration (VLSI) circuit. The circuit processes one millisecond of incoming signal and uses a segmented matched filter (SMF) by which the segmentation provides some tolerance to Doppler shift. The thesis presents simulation results of averaging for tens of seconds. Through simulation, the SMF is compared with a transversal matched filter (TMF) under conditions of no Doppler shift; coherent and non-coherent integration are discussed. The simulation is conducted at 290 K (17°C) such that the Boltzmann noise is -204 dBW/Hz, with a GPS signal bandwidth of 2 MHz and signal level of -185 dBW, and the receiver input signal-to-noise ratio (SNR) is -44 dB.<p> The SMF is applied using differing segment lengths to high-sensitivity GPS data from indoor and urban simulated GPS data. The results demonstrate the SMFs ability to tolerate Doppler frequency offsets while allowing for long integration times to detect the weak GPS signals.

Recent government regulations for Enhanced 911 locating of wireless handsets require accuracy to within 50 and 300 meters. Two technologies under consideration are triangulation using existing wireless base stations and location using global positioning satellites (GPS). Satellite positioning is the leading candidate, however, reception of GPS signals within large buildings is difficult and considerable research is devoted to this topic. Conventional GPS receivers require line of sight to at least four satellites and, under outdoor conditions, the expected signal level is about -160 dBW. Within large buildings, detection is very difficult because there is high thermal noise and some satellite signals can be attenuated to less than -185 dBW while others can suffer little attenuation. In order to construct the pseudo-ranges necessary for position finding, the receiver must synchronize to the incoming codephase of each satellite and must operate with substantial Doppler frequency offset caused by satellite motion.<p> This thesis investigates the application of a parallel non-coherent spread spectrum synchronizer previously implemented as a very-large-scale integration (VLSI) circuit. The circuit processes one millisecond of incoming signal and uses a segmented matched filter (SMF) by which the segmentation provides some tolerance to Doppler shift. The thesis presents simulation results of averaging for tens of seconds. Through simulation, the SMF is compared with a transversal matched filter (TMF) under conditions of no Doppler shift; coherent and non-coherent integration are discussed. The simulation is conducted at 290 K (17°C) such that the Boltzmann noise is -204 dBW/Hz, with a GPS signal bandwidth of 2 MHz and signal level of -185 dBW, and the receiver input signal-to-noise ratio (SNR) is -44 dB.<p> The SMF is applied using differing segment lengths to high-sensitivity GPS data from indoor and urban simulated GPS data. The results demonstrate the SMFs ability to tolerate Doppler frequency offsets while allowing for long integration times to detect the weak GPS signals.

OBJECTIVE: To evaluate whether the use of salmeterol is associated with an increased risk of an asthma-related hospitalization or emergency care among asthma patients. METHODS: The data for this study were extracted from the Medstat MarketScan® claims databases occurring between 01/01/00 and 12/31/01. A nested case-control study design was employed. A cohort representing asthma patients was identified in 2000. Among the study cohort, hospitalized cases were identified as those who had the firsttime asthma-related hospitalization in 2001, and were matched to select controls by age (± 5 years), sex, and the number of ambulatory visits for asthma (5:1 control to case ratio). A similar process was applied to evaluating an asthma-related emergency department (ED) visit. The odds of prior salmeterol exposure among cases compared to controls were estimated using conditional multiple logistic regressions. The covariates of interest comprised age, prior hospital admission or ED visit for asthma, number of canisters of inhaled short-acting β₂ agonists and use of other asthma medications. RESULTS: A total of 35,312 subjects were eligible to be the study cohort. In addition, 285 and 640 subjects were identified as hospitalized and ED cases, respectively. The non-significant association was found when the prior salmeterol exposure was treated as a dichotomized variable. However, it was found that one unit increase in the number of canisters of salmeterol was associated with a seven percent decrease in the risk of a hospital admission for asthma (p <0.001). Additionally, current use of salmeterol was associated with a 48 percent decrease in the risk of an asthma-related hospitalization (OR = 0.52; p <0.001). The protective effect of salmeterol did not exist for those with recent or past use of salmeterol. Similar findings were observed for the ED visit outcome. CONCLUSIONS: The use of salmeterol was not found to be associated with an increased risk of an asthma-related hospital admission or ED visit. Conversely, one unit increase in the number of canisters of salmeterol and current use of salmeterol, respectively, were found to decrease the risk in an asthma-related hospitalization or ED visit among asthma patients.

International Telemetering Conference Proceedings / October 28-31, 1996 / Town and Country Hotel and Convention Center, San Diego, California / It is well known that the pulse telemetering system whose system equipment is simple is superior to the continuous one in ultilizing signal power. But in designing a pulse telemetering receiver the frequency shift problem is often encountered, the shift often greatly wider than the signal bandwidth is very unfavorable for improving receiver working sensitivity. Either to limit transmitter frequency stability strictly or to adapt AFC system in receiver for tracking carrier wave can solve the problem above, the AFC system method could improve the receiver’s performance, but the equipment is complicated. To what extent the receiver working sensitivity will be effected and how to judge the effection in case of adapting VF matched filter and RF being wideband in receiver are this paper’s emphasis. In this paper the power density spectrum distribution of the white noise which has passed through the non-linear system-the linear detector is analysed theoretically, and the improved working sensitivity of the receiver with video matched filter and its difference sensitivity value to that of the optimal receiver are derived. The tested working sensitivity data of two kind pulse receivers with different RF bands are given and the theoretical calculation results conform well with these data, thus it is proven that adapting video matched filter in pulse receiver is a effective approach for compensating the receiver working sensitivity dropping from RF bandwidth increase.

Submitted by Alex Sandro R?go (alex@ifpb.edu.br) on 2016-11-23T14:14:27Z No. of bitstreams: 1 An?lise_e_Simula??o_de_Antenas_de_Microfita_Atrav?s_do_M?todo_FDTD.pdf: 6733290 bytes, checksum: d36f54b35c59746e26d58dc9e823c7d6 (MD5) / Approved for entry into archive by Alex Sandro R?go (alex@ifpb.edu.br) on 2016-11-23T14:15:20Z (GMT) No. of bitstreams: 1 An?lise_e_Simula??o_de_Antenas_de_Microfita_Atrav?s_do_M?todo_FDTD.pdf: 6733290 bytes, checksum: d36f54b35c59746e26d58dc9e823c7d6 (MD5) / Made available in DSpace on 2016-11-23T14:15:20Z (GMT). No. of bitstreams: 1 An?lise_e_Simula??o_de_Antenas_de_Microfita_Atrav?s_do_M?todo_FDTD.pdf: 6733290 bytes, checksum: d36f54b35c59746e26d58dc9e823c7d6 (MD5) Previous issue date: 2016-11-23 / Este trabalho tem como finalidade a aplica??o do m?todo das Diferen?as Finitas no Dom?nio do Tempo - Finite Difference Time Domain ? FDTD para an?lise num?rica de antenas de microfita, atrav?s de um programa escrito em linguagem C++. A condi??o de contorno absorvedora necess?ria adotada, para converg?ncia dos resultados, foi a camada perfeitamente casada - Perfect Matched Layer ? PML, posicionada em volta do dom?nio computacional. Para os quatro modelos de antenas propostos, os resultados do par?metro S11 foram encontrados por um programa desenvolvido em linguagem Matlab e os resultados obtidos para os modelos de antenas propostos, foram validados experimentalmente pela constru??o f?sica e medi??o com o analisador de redes vetorial Agilent N5230A e com o software comercial Ansys Design.

Human microbial research has become increasingly popular in biomedical areas due to the importance of role of human microbiome in human health. One purpose of studying human microbiome is to detect differentially abundant features from a limited group of subjects across biological conditions. Metagenomic analyses of the human microbial communities are extensively used for biomedical applications due to its reliable and evident comparative discoveries across more than one metagenomes when multiple communities are taken into consideration. Next-generation sequencing technology helps to detect taxonomic compositions of specific features/species contained in human microbial communities. Statistical analysis often starts by generating the Operational Taxonomic Units (OTUs) using taxonomic compositions to classify groups of closely associated human microbiomes. Oftentimes, the counts of features are observed as matched count data with excess zeros. Such data lead some differential abundance analysis methods to apply Zero-Inflated Poisson (ZIP) or Zero-Inflated Negative Binomial (ZINB) regression for modeling the microbial abundance. However, over-dispersion as well as within-subject variation and correlation of matched count data render the standard ZIP and ZINB regression inadequate. To account for the inherent within-subject variation and correlation, independent random effect terms are commonly included in the regressions. Therefore, a robust method that accounts the effect of matched samples and correlated random effects while considering over-dispersion and excess zeros of count data is need for statistical analysis. In this paper, a statistical method, the two-part correlated ZINB model with correlated random effects (cZINB), is proposed for testing the matched samples with repeated measurements.

No description available.

This study seeks to: (1) determine if differences exist between children with Specific Language Impairment (SLI) compared to age-matched (AM) and language- matched (LM) children with typical language development (TL) in rates and proportions of five types of metalinguistic productions and (2) test theories of metalinguistic production. Forty-five children, 24 with TL and 21 with SLI, paired for age or language level, formed two groups. Previously collected data from two studies of verb learning (Proctor-Williams & Fey, 2007; Proctor- Williams, unpublished) were analyzed for rates and types of metalinguistic productions. Results yielded no within or between group significant differences in the rates types. There were differences in proportional use of types of metalinguistic utterances in the LM group. This study showed that children as young as 3;0 produce metalinguistic utterances. Further, it disproved the Piagetian-Based Metalinguistic Development Theory. Interesting trends suggest direction for future research.