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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
71

Acquisition and tracking of weak GPS signals as received by cellular telephones

Grant, Howard Alexander 25 January 2011 (has links)
This thesis investigates the suitability of global navigation satellite system (GNSS) signals for cellular phone location. The requirement is to determine and report the location of a phone during an emergency call.<p> The thesis analyzes acquisition and tracking techniques suitable for very weak signals as received by a cellular phone indoors. The L1 and L5 signals from GPS satellites and the L1 signal from Galileo satellites are considered. It is shown that long integration times and coherent integration are required for the weakest expected signals. Long coherent integration times require a precise knowledge of the Doppler shift due to the range rate of the satellite. The tolerance to Doppler shift can be increased by using FFTs in the analysis of the data. Non-coherent averaging techniques improve the Doppler tolerance but compared to coherent averaging, the loss of signal to noise ratio is too large for the weakest signals.<p> Coherent averaging of the GPS L1 signal requires data removal that can be accomplished with assistance from the cellular network. The GPS L5 and Galileo L1 signals include a data-less or pilot channel. The GPS L5 pilot channel includes a 20 bit Neuman Hoffman code with a bit period of 1 ms. This code has to be acquired or removed before coherent averaging. Similarly the Galileo pilot channel includes a 25 bit short code.<p> Once code acquisition has been accomplished, it is necessary to track the signals from at least four satellites for long enough to compute a position estimate. A discussion of tracking techniques is included to show the signal to noise ratio limitations for adequate tracking accuracy.<p> The results show that GNSS signals are suitable for cellular phone location in a large number of situations. Increased receiver sensitivity would permit location in additional situations. In rural situations GNSS may be the only available option.
72

Signals from the financial crisis : A study based on the effects of dividends signaling during the financial crisis on the Swedish Stock Exchange

Jahanzeb, Danish, Jönsson, Gunnar, Eriksson, Joakim January 2012 (has links)
No description available.
73

A Low-noise Instrumentation Amplifier for Neural Signal Sensing and a Low-power Implantable Bladder Pressure Monitor System

Liou, Jian-Sing 11 July 2007 (has links)
The thesis is composed of two topics : a low-noise instru-mentation amplifier (IA) for neural signal sensing and a low-power implantable bladder pressure monitor SOC (system-on-chip). A low-noise instrumentation amplifier for bio-medical appli-cations is proposed in the first topic. It is designed for sampling vague neural signals thanks to its high gain, high CMRR in a pre-defined bandwidth. A low-power implantable bladder pressure monitor system is presented in the next topic. The system contains several parts : a commercial pressure sensor, an IA, an analog to digital converter (ADC), a parallel to serial converter (PtoS), an RF transmitter and a sleep controller. The IA with 1-atm canceling is designed for high resolution and linearity in the pre-defined bladder pressure range. For low power and low speed applications, a successive approximation ADC (SA ADC) is employed in the system. A clear flag is added to the PtoS to enhance reliability. Our chip saves a great portion of power to extend the processing time owing to the novel sleep controller.
74

Songs of a humpback whale (Megaptera novaeangliae) in Taiwan and evolution of communication in cetaceans

Yu, Hsin-Yi 09 September 2002 (has links)
Humpback whales (Megaptera novaeangliae) belong baleen whales. They migrate between high-latitude summer feeding regions and low-latitude wintering regions where calving and make place.There were 1~60 humpback whales whaled every year during 1920~1967 in southern Taiwan. However, only a few sights were recorded in the past twenty years. A male humpback whale was sighted on the east coast of Taiwan in March, 2000. His songs recorded during between three-day tailing were analysed. There were five themes and nine units in the songs, a complete song duration lasted about 14.2 minutes. The maximal sound pressure level was 189.6 dB (n=32, SEM =2.81). The acoustic characters (i.e., signal duration, time between two signals, theme duration, fundamental frequency) of the songs were not significant different. A visual comparison of the spectrograms of the sound units from this particalar whale with those northwest Pacific Ocean showed similarity. This individual was a member of the population in the northwest Pacific Ocean. This conclusion was also supported by the result of Photo-ID of its fluke. Ceatceans live in the water and develop the special model to produce sounds. There are two kinds of communicative signals: pulses and whistles. These two signals were characters of phylogenetic relationship and the outgroup was red deer. There were two monophyletic groups. Evolution of communicative signals in cetaceans was whistle existent and added the pulses signals. Last, the whistles lost and only with pulses. The fumctions of pulse signals in communication was unknown in delphinidae. Sperm whales, pygmy sperm whales, dwarf sperm whales, Baird¡¦s beaked whales and Hector¡¦s dolphins were only use pulse signals. The reason of this change was unclear.
75

Subsurface conductive isolation of refraction correlative magnetic signals (SCIRCMS)

Erck, Eric Stephenson 15 November 2004 (has links)
Isolation of terrestrially-observed magnetic signals by restoring their diffusive loss due to subsurface electrical conductivity sufficiently correlates these signals with those derived from the Alfven ionospheric electron movement of refraction variation. Temporary magnetic observatories were established on a conductive sedimentary basin (with a sampling interval of 5 s) and on a resistive large igneous intrusion (with a sampling interval of 10 s). Conventional modeling techniques estimate and remove the effects of the magnetometer, geomagnetic diurnal changes, whorls (solar quiet current vortices), and some bays from the acquired signals. Conventional one-dimensional skin depth modeling estimates the diffusive attenuation. The residual magnetic signal and the diffusive filter (as applied to the topography) become quantities in the linear system estimation of the geoelectric subsurface. Angular frequency domain least squares solution of the equations yields an isolated magnetic anomaly spectrum. Interpretive refinement, by selection of the zero or near zero curvature onset of either the spectrum's real or imaginary component, critically prepares the signal solution for correlation to a pseudomagnetic anomaly signal. This is an independently-derived sequence of anomalous values derived from Global Positioning System (GPS) refracted ranges. Detailed application of the Biot-Savart law provides independent anomaly signals to which the magnetic anomalies correlations show great correlation improvement by the isolation. These correlation improvements are from 2% to 83% and 9% to 91% for the sedimentary basin and from 2% to 96% and 24% to 78% for the igneous intrusion.
76

Exploring the jumping spider mimicry of Eugauria albidentata (Lepidoptera, Crambidae, Musotiminae) through ethological and visual ecological approaches

Wang, Mu-Yun 12 August 2009 (has links)
Predator mimicry refers to a peculiar and rarely investigated example of Batesian mimicry in nature. This mimicry scenario exists between predator and prey in which prey resembles the form, behaviour or signals exhibited by the predator to avoid or reduce risk of predation. In the Lepidoptera, there are many micromoth taxa that are phylogenetically unrelated and geographically widespread exhibiting colour patterns that are putatively involved in jumping spider mimicry. In the present study, we aimed to answer the following questions: (1) what kinds of colour pattern and display behaviour could really allow the moths to participate in jumping spider mimicry? (2) does the moth receive different predation pressure from male and female spiders? (3) why is the mimetic moth not immediately taken by the spider? Is it really because the spider sees the moth as another spider? (4) Is there any evidence justifying any visual signal displayed by the moth participated in the jumping spider mimicry? The experimental results showed that the predation rates on mimetic moths of jumping spider were significantly lower than the non-mimetic moths, and spiders exhibited specific behaviour that was displayed for conspecific communication. But not all the presuming mimicking moths can decrease predation from the spiders. Female spiders show significantly higher predation rate to the mimicking moths, while male spiders tend to display more frequently to the moth. In behaviour comparison test in male jumping spiders, we found the behaviour displayed toward mimicking moths are closer to conspecific or heterospecific female spiders, suggesting that female spiders are more likely to be the model of the mimicry systems. Previous studies have shown that UV and fluorescent signals are important in courting behaviour of jumping spider, so we block the UV reflectance signals on the wing pattern of the mimetic moths. The results show that the predation rate of moths without the UV signals is significantly higher than control group which blocked the non-ultraviolet patterns. However, there were still several jumping spiders displayed to the UV-blocking moth, suggesting the UV signals are not the only feature participate in the jumping spider mimicry system.
77

Traffic signal control with ant colony optimization a thesis /

Renfrew, David. Yu, Helen. January 1900 (has links)
Thesis (M.S.)--California Polytechnic State University, 2009. / Mode of access: Internet. Title from PDF title page; viewed on Jan. 7, 2010. Major professor: Helen Yu. "Presented to the faculty of California Polytechnic State University, San Luis Obispo." "In partial fulfillment of the requirements for the degree [of] Master of Science in Electrical Engineering." "2009." Includes bibliographical references (p. 82-83).
78

Robustness approach to the integrated network design problem, signal optimization and dynamic traffic assignment problem

Karoonsoontawong, Ampol 28 August 2008 (has links)
Not available / text
79

BEHAVIOR AND DESIGN OF MONOTUBE SIGN SUPPORT STRUCTURES (VORTEX SHEDDING, DYNAMIC FORCES, STRAIN GAGE, FIELD TESTING, COMPUTER MODEL)

Martin, Kipp Alan January 1985 (has links)
No description available.
80

Determination of the effect of a traffic light on vehicular delay

Williams, Robert Wade, 1940- January 1967 (has links)
No description available.

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