180 research outputs found
Non-Intrusive Subscriber Authentication for Next Generation Mobile Communication Systems
Merged with duplicate record 10026.1/753 on 14.03.2017 by CS (TIS)The last decade has witnessed massive growth in both the technological development, and
the consumer adoption of mobile devices such as mobile handsets and PDAs. The recent
introduction of wideband mobile networks has enabled the deployment of new services
with access to traditionally well protected personal data, such as banking details or
medical records. Secure user access to this data has however remained a function of the
mobile device's authentication system, which is only protected from masquerade abuse by
the traditional PIN, originally designed to protect against telephony abuse.
This thesis presents novel research in relation to advanced subscriber authentication for
mobile devices. The research began by assessing the threat of masquerade attacks on
such devices by way of a survey of end users. This revealed that the current methods of
mobile authentication remain extensively unused, leaving terminals highly vulnerable to
masquerade attack. Further investigation revealed that, in the context of the more
advanced wideband enabled services, users are receptive to many advanced
authentication techniques and principles, including the discipline of biometrics which
naturally lends itself to the area of advanced subscriber based authentication.
To address the requirement for a more personal authentication capable of being applied
in a continuous context, a novel non-intrusive biometric authentication technique was
conceived, drawn from the discrete disciplines of biometrics and Auditory Evoked
Responses. The technique forms a hybrid multi-modal biometric where variations in the
behavioural stimulus of the human voice (due to the propagation effects of acoustic
waves within the human head), are used to verify the identity o f a user. The resulting
approach is known as the Head Authentication Technique (HAT).
Evaluation of the HAT authentication process is realised in two stages. Firstly, the
generic authentication procedures of registration and verification are automated within a
prototype implementation. Secondly, a HAT demonstrator is used to evaluate the
authentication process through a series of experimental trials involving a representative
user community. The results from the trials confirm that multiple HAT samples from
the same user exhibit a high degree of correlation, yet samples between users exhibit a
high degree of discrepancy. Statistical analysis of the prototypes performance realised
early system error rates of; FNMR = 6% and FMR = 0.025%. The results clearly
demonstrate the authentication capabilities of this novel biometric approach and the
contribution this new work can make to the protection of subscriber data in next
generation mobile networks.Orange Personal Communication Services Lt
Recent Advances in Signal Processing
The signal processing task is a very critical issue in the majority of new technological inventions and challenges in a variety of applications in both science and engineering fields. Classical signal processing techniques have largely worked with mathematical models that are linear, local, stationary, and Gaussian. They have always favored closed-form tractability over real-world accuracy. These constraints were imposed by the lack of powerful computing tools. During the last few decades, signal processing theories, developments, and applications have matured rapidly and now include tools from many areas of mathematics, computer science, physics, and engineering. This book is targeted primarily toward both students and researchers who want to be exposed to a wide variety of signal processing techniques and algorithms. It includes 27 chapters that can be categorized into five different areas depending on the application at hand. These five categories are ordered to address image processing, speech processing, communication systems, time-series analysis, and educational packages respectively. The book has the advantage of providing a collection of applications that are completely independent and self-contained; thus, the interested reader can choose any chapter and skip to another without losing continuity
Scalable and perceptual audio compression
This thesis deals with scalable perceptual audio compression. Two scalable perceptual solutions as well as a scalable to lossless solution are proposed and investigated. One of the scalable perceptual solutions is built around sinusoidal modelling of the audio signal whilst the other is built on a transform coding paradigm. The scalable coders are shown to scale both in a waveform matching manner as well as a psychoacoustic manner. In order to measure the psychoacoustic scalability of the systems investigated in this thesis, the similarity between the original signal\u27s psychoacoustic parameters and that of the synthesized signal are compared. The psychoacoustic parameters used are loudness, sharpness, tonahty and roughness. This analysis technique is a novel method used in this thesis and it allows an insight into the perceptual distortion that has been introduced by any coder analyzed in this manner
Software and hardware implementation techniques for digital communications-related algorithms
There are essentially three areas addressed in the body of this thesis. (a) The first is a theoretical investigation into the design and development of a practically realizable
implementation of a maximum-likelihood detection process to deal with digital data transmission over
HF radio links. These links exhibit multipath properties with delay spreads that can easily extend over 12
to 15 milliseconds. The project was sponsored by the Ministry of Defence through the auspices of the Science
and Engineering Research Council. The primary objective was to transmit voice band data at a minimum
rate of 2.4 kb/s continuously for long periods of time during the day or night. Computer simulation
models of HF propagation channels were created to simulate atmospheric and multipath effects of transmission
from London to Washington DC, Ankara, and as far as Melbourne, Australia. Investigations into
HF channel estimation are not the subject of this thesis. The detection process assumed accurate knowledge
of the channel. [Continues.
Parallelism and the software-hardware interface in embedded systems
This thesis by publications addresses issues in the architecture and microarchitecture of next generation, high performance streaming Systems-on-Chip through quantifying the most important forms of parallelism in current and emerging embedded system workloads. The work consists of three major research tracks, relating to data level parallelism, thread level parallelism and the software-hardware interface which together reflect the research interests of the author as they have been formed in the last nine years. Published works confirm that parallelism at the data level is widely accepted as the most important performance leverage for the efficient execution of embedded media and telecom applications and has been exploited via a number of approaches the most efficient being vectorlSIMD architectures. A further, complementary and substantial form of parallelism exists at the thread level but this has not been researched to the same extent in the context of embedded workloads. For the efficient execution of such applications, exploitation of both forms of parallelism is of paramount importance. This calls for a new architectural approach in the software-hardware interface as its rigidity, manifested in all desktop-based and the majority of embedded CPU's, directly affects the performance ofvectorized, threaded codes. The author advocates a holistic, mature approach where parallelism is extracted via automatic means while at the same time, the traditionally rigid hardware-software interface is optimized to match the temporal and spatial behaviour of the embedded workload. This ultimate goal calls for the precise study of these forms of parallelism for a number of applications executing on theoretical models such as instruction set simulators and parallel RAM machines as well as the development of highly parametric microarchitectural frameworks to encapSUlate that functionality.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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