- 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.
Search results
Showing 1 to 3 of 3 (0.05 seconds)| 1 |
NEPTSim: simulating NEPTUNE Canada using OMNeT++Martonalti, Burak 29 August 2012 (has links)
North-East Pacific Undersea Network Experiments (NEPTUNE) is a multi-node cabled ocean observatory linked by 818 kilometers of powered fiber optic cable off-shore
from Vancouver Island across the northern Juan de Fuca tectonic plate. It includes
a Data Management and Archive Station (DMAS) at the University of Victoria (UVic)
and a shore station at Port Alberni, BC, Canada. The core of the
network consists of 6 branching units, 6 node stations, 13 junction boxes and more
than 130 instruments.
In this paper, we explore the costs and benefits of constructing a simulator for
NEPTUNE using the OMNeT++ simulation platform---a C++ based discrete-event
simulator. In this context, we present the design and implementation of a simple
simulator that can work with a variety of configurations of instruments, where
the instruments are connected to DMAS via junction boxes and branching units, and
generate TCP and UDP traffic following certain patterns. The simulator is
designed for supporting \emph{what-if} scenario analysis, particularly with
respect to system evaluation and discovery of limits associated with network
traffic behaviors. Our study reveals that, although building the simulator in
OMNeT++ has many advantages such as ease of tuning and calibration, capturing
sufficient details regarding the working behavior of the actual NEPTUNE
environment is still challenging. A survey of alternative tools, including
NS-2/NS-3, OPNET, JiST/SWANS, J-Sim, SSFNet, and Qualnet reveals that these
nuances would not be any less challenging within these simulation environments. / Graduate
|
| 2 |
Temporal Variations in the Compliance of Gas Hydrate FormationsRoach, Lisa Aretha Nyala 20 March 2014 (has links)
Seafloor compliance is a non-intrusive geophysical method sensitive to the shear modulus of the sediments below the seafloor. A compliance analysis requires the computation of the frequency dependent transfer function between the vertical stress, produced at the seafloor by the ultra low frequency passive source-infra-gravity waves, and the resulting displacement, related to velocity through the frequency. The displacement of the ocean floor is dependent on the elastic structure of the sediments and the compliance function is tuned to different depths, i.e., a change in the elastic parameters at a given depth is sensed by the compliance function at a particular frequency. In a gas hydrate system, the magnitude of the stiffness is a measure of the quantity of gas hydrates present. Gas hydrates contain immense stores of greenhouse gases making them relevant to climate change science, and represent an important potential alternative source of energy. Bullseye Vent is a gas hydrate system located in an area that has been intensively studied for over 2 decades and research results suggest that this system is evolving over time.
A partnership with NEPTUNE Canada allowed for the investigation of this possible evolution. This thesis describes a compliance experiment configured for NEPTUNE Canada’s seafloor observatory and its failure. It also describes the use of 203 days of simultaneously logged pressure and velocity time-series data, measured by a Scripps differential pressure gauge, and a Güralp CMG-1T broadband seismometer on NEPTUNE Canada’s seismic station, respectively, to evaluate variations in sediment stiffness near Bullseye. The evaluation resulted in a (- 4.49 x10-3± 3.52 x 10-3) % change of the transfer function of 3rd October, 2010 and represents a 2.88% decrease in the stiffness of the sediments over the period. This thesis also outlines a new algorithm for calculating the static compliance of isotropic layered sediments.
|
| 3 |
Temporal Variations in the Compliance of Gas Hydrate FormationsRoach, Lisa Aretha Nyala 20 March 2014 (has links)
Seafloor compliance is a non-intrusive geophysical method sensitive to the shear modulus of the sediments below the seafloor. A compliance analysis requires the computation of the frequency dependent transfer function between the vertical stress, produced at the seafloor by the ultra low frequency passive source-infra-gravity waves, and the resulting displacement, related to velocity through the frequency. The displacement of the ocean floor is dependent on the elastic structure of the sediments and the compliance function is tuned to different depths, i.e., a change in the elastic parameters at a given depth is sensed by the compliance function at a particular frequency. In a gas hydrate system, the magnitude of the stiffness is a measure of the quantity of gas hydrates present. Gas hydrates contain immense stores of greenhouse gases making them relevant to climate change science, and represent an important potential alternative source of energy. Bullseye Vent is a gas hydrate system located in an area that has been intensively studied for over 2 decades and research results suggest that this system is evolving over time.
A partnership with NEPTUNE Canada allowed for the investigation of this possible evolution. This thesis describes a compliance experiment configured for NEPTUNE Canada’s seafloor observatory and its failure. It also describes the use of 203 days of simultaneously logged pressure and velocity time-series data, measured by a Scripps differential pressure gauge, and a Güralp CMG-1T broadband seismometer on NEPTUNE Canada’s seismic station, respectively, to evaluate variations in sediment stiffness near Bullseye. The evaluation resulted in a (- 4.49 x10-3± 3.52 x 10-3) % change of the transfer function of 3rd October, 2010 and represents a 2.88% decrease in the stiffness of the sediments over the period. This thesis also outlines a new algorithm for calculating the static compliance of isotropic layered sediments.
|
Page generated in 0.0574 seconds