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Det finns idag fortfarande komponenter i det globala mobilnätet som använder teknologi som utvecklades på 70-talet. Nyare, säkrare system har införts i flera länder, men även dessa behåller sin förmåga att kommunicera med de mer sårbara äldre systemen och delar därmed deras säkerhetsproblem. Det är speciellt protokollstacken SS7, grunden till 2G som har stora säkerhetsbrister. Syftet med denna uppsats är primärt att designa samt implementera en Elastic Stack pipeline och avgöra vad för information som kan erhållas vid användandet av denna pipeline på SS7-signaleringstrafik från ett faktiskt mobilnätssystem. Ur detta formulerades även ett antal delsyften. En pipeline implementerades och testades ihop med flera olika format på inläst data. Det gjordes fyra experiment där olika funktionaliteter testades med hjälp av utvalda dataset vars syfte var att agera substitut till den sekretessbelagda faktiska mobilnätsdatan. Elastic Stack är enligt vår uppfattning ett lovande verktyg för att övervaka och analysera SS7-signaleringstrafik, men det finns ett antal hinder som bara delvis beror på att mjukvaran är under utveckling. Dessa går dock till större del att kringgå. / There are currently components of the global mobile network that use technology developed in the 1970s. Newer, more secure systems have been introduced in several countries, but even these retain their ability to communicate with the more vulnerable older systems, and thus share their security issues. The purpose of this thesis is primarily to design and implement an Elastic Stack pipeline and determine what information can be attained through the use of this pipeline on SS7 signalling traffic from an actual mobile network system. To accomplish this, a series of sub-purposes also emerged. A pipeline was implemented and tested with several different formats of data. A series of four experiments were performed where different functionalities were tested with the help of selected data sets whose purpose was to act as substitutes for the classified actual mobile network data. Elastic Stack is, in our opinion, a promising tool for monitoring and analyzing SS7 signalling traffic, but there are a number of issues that can only partially be attributed to the software being still in development. They are however largely circumventable.

published_or_final_version / Civil Engineering / Master / Master of Philosophy

Forward modelling of seismic waves is an essential tool in the determination of the underlying structure of the Earth using inversion techniques. Despite recent advances in computer power and memory resources, full 3-D elastic wave modelling continues to place a heavy burden on a typical personal computer. 2.5-D modelling reduces the computational burden while maintaining 3-D wavefield characteristics. In this thesis I present 2.5-D frequency-domain equations of motion for elastic wave modelling in anisotropic media. The reduced set of equations for vertical transversely isotropic media and tilted transversely isotropic media are presented separately. Using the spectral-element method, I develop the equations of motion into readily implemented sub-equations by identifying simple 1-D and 2-D patterns. Some aspects of my computational implementation are unique, in particular the use of a system of dynamically growing binary trees to serve as a system matrix. Using this system, the matrix is automatically stored in compressed row format. I investigate the use of both distributed memory and shared memory super-computers for 3-D modelling and compare the resource use of various matrix solvers. In this thesis I adapt recently developed Perfectly Matched Layer formulations to the 2.5-D elastic case, and find them to be adequate in most situations. I investigate the possiblity of instability in the absorbing layers. Observation of 2.5-D modelling results in the frequency wavenumber domain uncovers polelike behaviour at critical wavenumbers within the spectrum. I demonstrate how this behaviour threatens the accuracy of the inverse Fourier transformed frequency-domain solution. However for inhomogeneous media, under certain conditions the only medium that exhibits pole-like behaviour is the medium containing the source. Further study of the phenomenon shows that in homogeneous, transversely isotropic media, the critical wavenumber values are not dependent on the receiver position, but rather can be predicted using the maximum phase velocities of the media. The recommended strategy for wavenumber sampling is to use dense even spacing of values, to adequately capture the behaviour close to the critical wavenumbers. A further recommendation it to introduce slight attenuation through the use of complex velocities (or elastic constants) to eliminate any pole-like behaviour at the critical values. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1385923 / Thesis (Ph.D.) -- University of Adelaide, School of Chemistry and Physics, 2010

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Made available in DSpace on 2014-10-09T12:29:25Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:00:39Z (GMT). No. of bitstreams: 1 01029.pdf: 5499422 bytes, checksum: 501fd6bc9c54b1b427d23b7e12ab1e1b (MD5) / Dissertacao (Mestrado) / IEA/D / Instituto de Energia Atomica - IEA