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Carrier recovery for 49 quadrature partial response signalsJordaan, G.D. January 2008 (has links)
Published Article / A reference carrier signal should be regenerated from a received partial response (PR) signal in order to facilitate optimal demodulation of the received signal. This paper describes the development and evaluation of such a carrier recovery system using DSP techniques.
The relative phase of a free-running local oscillator at the receiver is synchronized with the carrier signal of a received 49 quadrature partial response signal (49QPRS). Synchronization is achieved and maintained by means of a process of cross-correlation.
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CHAOTIC SPREAD-SPECTRUM SEQUENCE GENERATED BY MULTILEVEL QUANTIFYING AND THEIR PROPERTIESChengquan, Au, Tingxian, Zhou 10 1900 (has links)
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, California / According to the advantages of chaotic analog sequences and chaotic binary sequences, this paper proposes a method generating chaotic binary spread-spectrum sequence by multilevel quantifying. This paper proved that even correlation and odd correlation between such sequences of length N are all Gaussian distributed with mean 0 and variance N, the even of mean-square cross-correlation is N, and the variance of mean-square cross-correlation is 2N. The method can increase the number of chaotic sequences, made the spread-spectrum system more secure. The theoretical analyses and the results of simulation show that the performance of such sequence general is as same as traditional spread-spectrum sequence, its number is very large, and can be used in CDMA in future.
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Phylogeography and the evolution of correlated traits under multiple origins of aposematism in the poison frog familySantos, Juan Carlos 22 October 2009 (has links)
Living organisms are under selection not only for one, but also for several
inheritable characters at the same time. Well-sampled and well-supported
phylogenies are necessary for the studies of character evolution and their history.
The poison frogs (Dendrobatidae) are a well-known example of aposematism in
anurans. They include ~270 species of Neotropical frogs with aposematic (toxic
and conspicuous) and non-defended (palatable and cryptic) species. The origin of
aposematism in poison frogs is puzzling, because of its predicted low probability
of establishment due to the prey's increased conspicuousness. Previous studies
suggested a single origin of toxicity and warning coloration. By expanding taxon
sampling of the group, I reexamined the phylogenetic correlation between the
origins of toxicity and warning coloration. I found four or five independent
origins of aposematism; by using simulations, I rejected hypotheses of one, two, or three origins of aposematism (P < 0.002). I also found that diet specialization is
linked with the evolution of aposematism and has evolved independently at least
two times. Poison frogs are endemic to the Neotropic, which is one of the Earth's
largest reservoir of biodiversity. I reconstructed the biogeography of the poison
frog clade and rejected an Amazonian center-of-origin in favor of a model
expanding over the Neotropics. I inferred 14 dispersals into and 18 out of
Amazonia to adjacent regions; the Andes were the major source of dispersals into
Amazonia. Significant percentage of dendrobatid diversity in Amazonia and
Chocó resulted from repeated immigrations, with radiations at <10.0 million years
ago. In contrast, the Andes, Venezuelan Highlands, and Guiana Shield have
undergone extended in situ diversification at near constant rate since the
Oligocene. Poison frogs have significant variation on their physiological
characteristics. I measured resting and active metabolic rates of 54 species. I
traced metabolic measurements along aposematism, diet specialization, molecular
rates, and body mass. I found a synergistic and co-adapted functionality of active
metabolic rates with all previous traits that is perhaps the consequence of the
increase in complexity in most biological systems. My thesis has expanded the
knowledge of the biology, phylogenetic history, and biogeography of the poison
frogs. / text
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A scale-invariant model for the three-mode factor analysis.January 1983 (has links)
by Wai-kwan Fong. / Bibliography: leaves 37-39 / Thesis (M.Phil.) -- Chinese University of Hong Kong, 1983
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Mutilple Sensor Anomaly CorrelationTsai, Min-ying 10 January 2012 (has links)
IDS (Intrusion Detection System) detect intrusions and generate alerts to administrator. With Internet more and more popular, IDS products a lot of alerts make administrators spend much time to analyze to understand the network situation. Many online services record services details on the log, as the same administrators spend much time to analyze logs. IDS suffer from several limitations : amount of alerts, most of the alerts are false positive, certain attacks may not be detected by IDS. To solve limitations of IDS, four alert correlation techniques : alert attributions similarity, predefined attack scenarios, multi-stage approaches, verification to filter positive alerts. Network attack consist of multiple steps, each step may leave evidences on log or detected by IDS. Service logs record normal and abnormal detail behaviors, IDS alerts record single attack step. Alerts and logs first merge into meta-alert and meta-log. Second, we use two features to filter meta-log. Then, correlate meta-alert and filtered meta-log to produce report to administrators.
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The correlation of temperature and velocity in a hot jetTsai, Hsi-Han 31 July 2001 (has links)
N/A
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Prediction of gas-hydrate formation conditions in production and surface facilitiesAmeripour, Sharareh 30 October 2006 (has links)
Gas hydrates are a well-known problem in the oil and gas industry and cost millions of
dollars in production and transmission pipelines. To prevent this problem, it is important
to predict the temperature and pressure under which gas hydrates will form. Of the
thermodynamic models in the literature, only a couple can predict the hydrate-formation
temperature or pressure for complex systems including inhibitors.
I developed two simple correlations for calculating the hydrate-formation pressure or
temperature for single components or gas mixtures. These correlations are based on over
1,100 published data points of gas-hydrate formation temperatures and pressures with and
without inhibitors. The data include samples ranging from pure-hydrate formers such as
methane, ethane, propane, carbon dioxide and hydrogen sulfide to binary, ternary, and
natural gas mixtures. I used the Statistical Analysis Software (SAS) to find the best
correlations among variables such as specific gravity and pseudoreduced pressure and
temperature of gas mixtures, vapor pressure and liquid viscosity of water, and
concentrations of electrolytes and thermodynamic inhibitors.
These correlations are applicable to temperatures up to 90úF and pressures up to 12,000
psi. I tested the capability of the correlations for aqueous solutions containing electrolytes
such as sodium, potassium, and calcium chlorides less than 20 wt% and inhibitors such as
methanol less than 20 wt%, ethylene glycol, triethylene glycol, and glycerol less than 40
wt%. The results show an average absolute percentage deviation of 15.93 in pressure and
an average absolute temperature difference of 2.97úF. Portability and simplicity are other advantages of these correlations since they are
applicable even with a simple calculator. The results are in excellent agreement with the
experimental data in most cases and even better than the results from commercial
simulators in some cases. These correlations provide guidelines to help users forecast
gas-hydrate forming conditions for most systems of hydrate formers with and without
inhibitors and to design remediation schemes such as:
÷ Increasing the operating temperature by insulating the pipelines or applying heat.
÷ Decreasing the operating pressure when possible.
÷ Adding a required amount of appropriate inhibitor to reduce the hydrateformation
temperature and/or increase the hydrate-formation pressure.
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On sampling from compound populationsBrown, George M. January 1900 (has links)
Thesis (Ph. D.)--University of Michigan, 1934. / Lithoprinted. "Reprinted from the Annals of Mathematical Statistics, November, 1933."
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A two-pronged approach to improve distant homology detectionLee, Marianne M. January 2009 (has links)
Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes bibliographical references (p. 91-100).
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Compositional data analysis of voting patterns陳志昌, Chan, Chee-cheong. January 1993 (has links)
published_or_final_version / Applied Statistics / Master / Master of Social Sciences
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