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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.
1

Channel Sounding

Iftikhar, Wajid, Raichl, Jaroslav January 2008 (has links)
<p>This thesis will setup and configure a channel sounding system, further it will set up a software environment for channel model extraction (characteristic of the channel) and evaluation.</p><p>The motivation of the project is to set up and configure a channel sounding system based a Spectral Analyzer (Agilent E4407B), Signal Generator (Agilent E8267D), Signal Studio and Matlab software. The main motivation is to evaluate capability of such a channel sounding system, and see if it can be used for future channel model extraction.</p><p>Channel Sounding is based on emitting RF signal from one antenna and receiving the RF signal at another antenna (spatial place), extracting the channel response. This project will start with getting familiar with the basic operation of the Spectral Analyzer (Agilent E4407B), the Signal Generator (Agilent E8267D) and Signal Studio. Then set up a channel sounding system with previous mentioned equipment. Then as practical exercise some channel sounding and channel model extraction will be conducted. Especially see what kind of parameters those are possible to extract, time delay, propagation paths etc.</p>
2

Sound scattering by marine organisms in the northeastern Pacific Ocean

Donaldson, Henry Adam 01 September 1967 (has links)
Sound scattering by marine organisms was studied off the Oregon coast and between Hawaii and Adak, Alaska. Variations in scattering were observed over a period of several hours, over did (24-hour) periods, from month to month, from inshore to offshore, in relation to biomass of midwater animals, and temperature and salinity. Usually one or two scattering layers migrated vertically, ascending or descending at dusk and dawn respectively. At times reflectors migrated between surface waters and upper scattering layers during twilight periods. No statistical difference was found between rates of ascent and descent because of the variability in rates of migration that was observed. The amount or thickness of scattering in the water column was found to vary from day to night and with seasons. There was a general trend for more scattering during night than day, yet it was not statistically significant. Seasonally, more scattering appeared to be present during the summer in some years but not in others. Surface scattering varied not in amount but in the type present during different seasons and between day and night. Geographically, scattering was found in smaller amounts in offshore than inshore waters of Oregon. Variations in scattering were noted among the water masses between Hawaii and Adak, Alaska. Geographic changes in scattering and biomass showed a positive correlation between euphausiid catches and the amount of scattering. However, euphausiids are not considered the only group scattering sound. The great amount of variability in scattering is discussed. It may be due to differences in the species causing scattering and variability in the behavior of individual species, possibly resulting from changes in light and temperature. / Graduation date: 1968
3

Channel Sounding

Iftikhar, Wajid, Raichl, Jaroslav January 2008 (has links)
This thesis will setup and configure a channel sounding system, further it will set up a software environment for channel model extraction (characteristic of the channel) and evaluation. The motivation of the project is to set up and configure a channel sounding system based a Spectral Analyzer (Agilent E4407B), Signal Generator (Agilent E8267D), Signal Studio and Matlab software. The main motivation is to evaluate capability of such a channel sounding system, and see if it can be used for future channel model extraction. Channel Sounding is based on emitting RF signal from one antenna and receiving the RF signal at another antenna (spatial place), extracting the channel response. This project will start with getting familiar with the basic operation of the Spectral Analyzer (Agilent E4407B), the Signal Generator (Agilent E8267D) and Signal Studio. Then set up a channel sounding system with previous mentioned equipment. Then as practical exercise some channel sounding and channel model extraction will be conducted. Especially see what kind of parameters those are possible to extract, time delay, propagation paths etc.
4

Small scale features in atmospheric temperature fields measured by ISAMS

Livesey, Nathaniel January 1995 (has links)
No description available.
5

An experimental and theoretical investigation of vertical electrical sounding (VES) techniques

Meshinchi-Asl, Mirsattar January 1996 (has links)
No description available.
6

The relationship between echo squared integration and fish abundance

Heist, Barry Gerbers. January 1980 (has links)
Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. Includes bibliographical references (leaves 77-78).
7

A balloon-borne optical aerosol and cloud detector

Pilipowskyj, Serhij. January 1965 (has links)
Thesis (M.S.)--University of Wisconsin, 1965. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (p. 42-44).
8

The relationship between echo squared integration and fish abundance

Heist, Barry Gerbers. January 1980 (has links)
Thesis (M.S.)--University of Wisconsin--Madison. / Typescript. Title from title screen (viewed Sept. 24, 2007). Includes bibliographical references (leaves 77-78). Online version of the print original.
9

Application of electrical resistivity in groundwater exploration in Cyprus

Kramvis, Sotiris C. January 1987 (has links)
A number of geophysical methods have been used in groundwater exploration in Cyprus. Of these, electrical resistivity has found the widest application in the investigation of the mostly unconsolidated extensive aquifers of the Mesaoria Plain and the alluvial aquifers of the rivers draining the Troodos massif. Special emphasis has been given in this study on the detailed investigation by means of electrical resistivity of the aquifers of Western Mesaoria, Central Mesaoria and the three main Paphos rivers of Dhiarizos, Xeros and Ezusa where the nature of the deposits and the scarcity of exposures diminish the effectiveness of conventional hydrogeological methods. Existing hydrogeological information and specially conducted resistivity measurements of the magnitude and extent of lateral and orientational resistivity variations indicate that conditions in Western Mesaoria, the Paphos rivers and the larger part of Central Mesaoria are on the main suitable for the application of the electrical sounding technique. Over 120 correlation soundings measured in these areas show close correspondence between hydrogeological and electrical layers and enable the establishment of working geoelectrical models according to which the rest of the 904 soundings have been interpreted. In Western Mesaoria subsurface conditions are fairly simple and laterally persistent and two subaquifers to the Western Mesaoria Upper Aquifer are indicated by the electrical and hydrogeological results. In Central Mesaoria subsurface conditions are more variable while groundwater salinity variations complicate the picture. Interpretation of sounding measurements has been based on several geoelectrical models. In the Paphos rivers subsurface conditions are simple and the basic geoelectrical model assumes the presence of two alluvial layers with different physical properties. Aquifer geometry and configuration are accurately defined by the electrical-hydrogeological results. The electrical properties of the aquifers and associated rocks are derived while aquifer potential and hydraulic transmissivity appear to be related directly to the aquifer transverse resistance.
10

Inversion of horizontal loop electromagnetic soundings over a stratified earth

Fullagar, Peter Kelsham January 1981 (has links)
A detailed study of electromagnetic induction in a sequence of conductive layers has been completed for the case when the inducing fields are generated by an alternating current in a horizontal loop. The study was undertaken with a view to the development of a computer program to perform automatic inversion of horizontal loop electromagnetic (HLEM) frequency soundings taken over horizontally stratified ground. The program constitutes a new implementation of the general approach of Backus and Gilbert (1967, 1968, 1970). By means of a linearised iterative scheme, it constructs layered conductivities which satisfy a given set of observations to an accuracy consistent with the observational uncertainties. Subsequently, the non-uniqueness admitted by the limited amount of data can be appraised by computing averages of the original constructed model and comparing them with averages corresponding to other dissimilar models which also satisfy the data. In examples the Backus-Gilbert averages faithfully reflect the character of the "true" conductivity in regions of high conductivity, but they are of limited value in delineating resistive zones. The program has been applied successfully to the inversion of real data from Grass Valley, Nevada. A uniqueness theorem is presented for inversion of HLEM frequency soundings. It has been proved that an unlimited quantity of perfectly accurate HLEM frequency soundings (at a fixed receiver location) suffices to completely determine the conductivity as a function of depth. This result, which is believed to be new, enhances the credibility of conclusions based on inversion of HLEM soundings. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

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