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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.
21

The design of special purpose horizontal geodetic control networks /

Sprinsky, William Harold January 1975 (has links)
No description available.
22

Geodetic levelling with the Global Positioning System /

Jaksa, Daniel S. Unknown Date (has links)
Thesis (MAppSc (Surveying)) -- University of South Australia, 1993
23

Supporting spatial orientation| Using resizable icons to visualize distant landmarks on mobile phones

Zhao, Jiayan 28 June 2016 (has links)
<p> Mobile phones have become so popular in navigation. Empirical studies, however, have implied several pitfalls of using these mobile systems. First of all, the small size of the mobile screen fragmentizes the map information so that users have to interact with the display frequently for fear of disorientation. In addition, generated navigation guides with continuous displays of routing information relieves users&rsquo; cognitive load, but the excessive reliance on the displayed spatial information keeps the users being mindless of the environment that impacts their acquisition of spatial knowledge. Later, landmarks as important referents were suggested to help users integrate the current surroundings with further decision points to support their sense of direction and cognitive mapping. But the small display limited users to access the landmarks located out of the view. To address this issue, designs attempt to display distant landmarks at the edge of screen as a way to overcome the aforementioned limits. In order to enhance spatial orientation while using mobile devices, this study introduced an improved design that not only display the direction but also the distance concept of distant landmarks by changing in size as an indicator of the distance from a user&rsquo;s location. Built on this, two kinds of mechanism were designed to present the distance concept by icons of different sizes: one is based on ratio scale that icons change in size continuously based on an established ratio to the actual distance between the user and the distant location. The other mechanism is based on ordinal scale which assigns one of three different sizes to a certain range of distance implying near, middle, and far. A formal user study was carried out to compare efficiency of these two mechanisms in four types of distance comparison tasks. Results show that ordinal icons are more effective than ratio icons in visualizing relative distances between two distant landmarks. But for both mechanisms, users have challenges distinguishing distant landmarks from local landmarks when displayed on screen simultaneously. A further step is to explore some other feasible options of representing distance.</p>
24

Local geoid determination from a combination of gravity and GPS data

Kamarudin, Md Nor January 1997 (has links)
No description available.
25

Satellite laser ranging and some geophysical applications

Hill, Christopher John January 1989 (has links)
No description available.
26

Résumé des opérations exécutées jusqu'à la fin de 1911 pour la Description géométrique détaillée des Alpes françaises ...

Helbronner, Paul, January 1912 (has links)
Thèse--Faculté des sciences de Paris. / Vol. I of the author's Description géométrique détaillée des Alpes françaises was published in 1910.
27

Internationale erdmessung ein beitrag zur preussisch-deutschen völkerrechtsgeschichte ...

Holmgren, Rolf. January 1927 (has links)
Inaug.-diss.--Tübingen. / "Literatur-verzeichnis": p. [5]-6.
28

Geodetic Imaging of Fault System Activity

Evans, Eileen Louise 04 June 2015 (has links)
Geodetic observations provide kinematic constraints on the behavior of tectonically active fault systems. Estimates of earthquake cycle activity derived from these constraints may depend on modeling assumptions and/or regularization of a geodetic inverse problem, which is often poorly conditioned. Common model assumptions may affect kinematic solutions and conclusions about physical properties of faults and fault zones. For example, within a geometrically complex fault system, parameterization of nearby faults may affect slip estimates on an individual fault. In addition, fault slip models are often regularized by assuming that slip varies smoothly in space, which may artificially smear slip estimates beyond physical boundaries. As an alternative to smooth regularization, the applied mathematics field of compressed sensing provides a suite of methods for recovering sparse solutions. Applied to GPS observations of the 2011 Tohoku earthquake, compressed sensing algorithms enable imaging of spatially localized slip during and following the earthquake, and identification of a sharp boundary between coseismic and postseismic slip. Similar algorithms recover quantized solutions and may be applied to models of plate boundary deformation. Beginning with a dense array of tectonic micro-plates bounded by mapped faults in North America, these methods can be used to detect coherent motions of groups of micro-plates behaving as larger active blocks, effectively quantifying the complexity of North America plate boundary deformation. By improving our ability to identify and compare kinematic constraints on earthquake cycle processes, we are able to characterize the spectrum of earthquake cycle behaviors and gain a deeper understanding of earthquake phenomenology and physics. / Earth and Planetary Sciences
29

Characterization of instabilities in the problem of elastic planetary tides

Frey, Sarah E. January 2004 (has links)
In 1911, A. E. H. Love published a linear elastic model for the tidal deformation of planetary bodies. Using numerical techniques that were unavailable to Love, surprising behaviors of the tidal solution have been found: tides of finite, even substantial, height are possible in the presence of an infinitesimal tide raiser, thus indicating some sort of instability. The Love tidal model was for the deformation of a homogeneous sphere. In order to better understand the nature of the instabilities in this model, I consider the effect of adding a radially dependent density profile to the model. For a given singularity, an increase in the initial density gradient causes the singularity to change locations in parameter space. For steep enough density gradient, the singularity is pushed outside the realm of physically meaningful parameter space for certain initial radial density profiles. Self-gravitation appears to be the likely mechanism for the driving of the tidal instability. The nature of the behavior of self-gravitation will be studied by considering an exact elastic formulation of the problem. In this way, a more complete view of the processes involved in the tidal deformation of a body can be explored. I find that each of the curves of singularity loci observed in the tidal problem correspond to instabilities in different modes for the exact elastic self-gravitation problem.
30

Paleoclimate studies for controversial continental paleogeographies: The application of spherical geodesic grids and climate models to Gondwana's Devonian apparent polar wander path

Moore, Thomas Leonard January 1999 (has links)
Paleomagnetic data acquired in the last 10 to 15 years have failed to clearly delineate the Devonian apparent polar wander (APW) path for Gondwana. Consequently, many paleogeographers and paleomagnetists have turned to paleoclimate data to assist in locating Gondwana. Paleoclimate data have been used to either support proposed paleomagnetic-based positions for Gondwana or to independently position the continent. Both of these approaches have problems, including how paleoclimate data are handled and the assumption of a zonal climate system. Several improvements of these approaches are proposed in this study. First, paleoclimate data were grouped into occurrences using a spherical geodesic grid system when statistical manipulations were to be performed. The use of occurrences reduces errors caused by variations in sampling resolution and post-depositional processes. Grid cells in the spherical geodesic grid systems are near-equal area and shape. A comparison between spherical geodesic grid systems with other grid systems showed that the spherical geodesic grids were the most stable grid system if used in combination with a technique called rotational minimization, which finds the fewest possible occurrences for a given data set. Second, two techniques commonly used in paleogeographic studies were modified and a third technique was introduced. The first two techniques, called the palepole zonality method and the modified pole-finder method, were designed to rate proposed pole positions for Gondwana using latitude-distribution models for paleoclimate data. The final method, the parametric climate-model method, uses a conceptual climate model to predict the climate of the continent, which was compared to regional climate inference models. The results of these techniques when applied to Gondwana suggested that the continent moved little during the Devonian: the pole moved from west-central Gondwana in the Early Devonian to the northwest or to the east by the Carboniferous. The results also show, however, that all of these techniques are limited in their ability to pick a single position for Gondwana. Consequently, the best path identified by these methods cannot be assumed to be correct and confirming paleomagnetic data are still required.

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