ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, Nevada / Real-time transmission of airborne images to a ground station is highly desirable in many telemetering applications. Such transmission is often through an error prone, time varying wireless channel, possibly under jamming conditions. Hence, a fast, efficient, scalable, and error resilient image compression scheme is vital to realize the full potential of airborne reconnaisance. JPEG2000, the current international standard for image compression, offers most of these features. However, the computational complexity of JPEG2000 limits its use in some applications. Thus, we present a scalable low complexity coder (SLCC) that possesses many desirable features of JPEG2000, yet having high throughput.

ITC/USA 2010 Conference Proceedings / The Forty-Sixth Annual International Telemetering Conference and Technical Exhibition / October 25-28, 2010 / Town and Country Resort & Convention Center, San Diego, California / This paper describes how a microcontroller based system can be used to generate the signals needed in a multiple-input multiple-output (MIMO) system transmitter. The limited computational speed of the microcontroller, along with other tasks which the controller may need to handle, places limits on the throughput of the system, and the complexity of the MIMO signal design. However this can be a low cost design, and the microcontroller can be used to perform other operations in the system, which may make it attractive in some applications.

ITC/USA 2011 Conference Proceedings / The Forty-Seventh Annual International Telemetering Conference and Technical Exhibition / October 24-27, 2011 / Bally's Las Vegas, Las Vegas, Nevada / A highly compressed image inevitably has visible compression artifacts. To minimize these artifacts, many compression algorithms exploit the varying sensitivity of the human visual system (HVS) to different frequencies. However, this sensitivity has typically been measured at the near-threshold level where distortion is just noticeable. Thus, it is unclear that the same sensitivity applies at the supra-threshold level where distortion is highly visible. In this paper, we measure the sensitivity of the HVS for several supra-threshold distortion levels based on our JPEG2000 distortion model. Then, a low-complexity JPEG2000 encoder using the measured sensitivity is described. For aerial images, the proposed encoder significantly reduces encoding time while maintaining superior visual quality compared with a conventional JPEG2000 encoder.

We consider Benjamini-Schramm limits of Rauzy Graphs of low-complexity words. Low-complexity words are infinite words (over a finite alphabet), for which the number of subwords of length n is bounded by some Kn --- examples of such a word include the Thue-Morse word 01101001... and the Fibonacci word. Rauzy graphs Rn (omega) have the length n subwords of omega as vertices, and the oriented edges between vertices indicate that two words appear immediately adjacent to each other in omega (with overlap); the edges are also equipped with labels, which indicate what "new letter" was appended to the end of the terminal vertex of an edge. In a natural way, the labels of consecutive edges in a Rauzy graph encode subwords of omega. The Benjamini-Schramm limit of a sequence of graphs is a distribution on (possibly infinite) rooted graphs governed by the convergence in distribution of random neighborhoods of the sequence of finite graphs. In the case of Rauzy graphs without edge-labelings, we establish that the Rauzy graphs of aperiodic low-complexity words converge to the line graph in the Benjamini-Schramm sense. In the same case, but for edge-labelled Rauzy graphs, we also prove that that the limit exists when the frequencies of all subwords in the infinite word, omega, are well defined (when the subshift of omega is uniquely ergodic), and we show that the limit can be identified with the unique ergodic measure associated to the subshift generated by the word. The eventually periodic (i.e. finite) cases are also shown. Finally, we show that for non-uniquely ergodic systems, the Benjamini-Schramm limit need not exist ---though it can in some instances--- and we provide examples to demonstrate the variety of possible behaviors.

Elastin is an essential extracellular protein that is a key component of elastic fibres, providing elasticity to cardiac, dermal, and arterial tissues. During the development of the human cardiovascular system, elastin self-assembles before being integrated into fibres, undergoing no significant turnover during the human lifetime. Abnormalities in elastin can adversely affect its self-assembly, and may lead to malformed elastic fibres. Due to the longevity required of these fibres, even minor abnormalities may have a large cumulative effect over the course of a lifetime, leading to late-onset vascular diseases. This thesis project has identified important, over-represented repetitive elements in elastin which are believed to be important for the self-assembly and elastomeric properties of elastin. Initial studies of single nucleotide polymorphisms (SNPs) from the HapMap project and dbSNP resulted in a set of genetic variation sites in the elastin gene. Based on these studies, glycine to serine and lysine to arginine substitutions were introduced in elastin-like polypeptides. The self-assembly properties of the resulting elastin-like polypeptides were observed under microscope and measured using absorbance at 440nm. Assembled polypeptides were also cross-linked to form thin membranes whose mechanical and physical properties were measured and compared. These mutations resulted in markedly different behavior than wild-type elastin-like proteins, suggesting that mutations in the repetitive elements of the elastin sequence can lead to adverse changes in the physical and functional properties of the resulting protein. Using next-generation sequencing, patients with thoracic aortic aneurysms are being genotyped to discover polymorphisms which may adversely affect the self-assembly properties of elastin, providing a link between genetic variation in elastin and cardiovascular disease.

Elastin is an essential extracellular protein that is a key component of elastic fibres, providing elasticity to cardiac, dermal, and arterial tissues. During the development of the human cardiovascular system, elastin self-assembles before being integrated into fibres, undergoing no significant turnover during the human lifetime. Abnormalities in elastin can adversely affect its self-assembly, and may lead to malformed elastic fibres. Due to the longevity required of these fibres, even minor abnormalities may have a large cumulative effect over the course of a lifetime, leading to late-onset vascular diseases. This thesis project has identified important, over-represented repetitive elements in elastin which are believed to be important for the self-assembly and elastomeric properties of elastin. Initial studies of single nucleotide polymorphisms (SNPs) from the HapMap project and dbSNP resulted in a set of genetic variation sites in the elastin gene. Based on these studies, glycine to serine and lysine to arginine substitutions were introduced in elastin-like polypeptides. The self-assembly properties of the resulting elastin-like polypeptides were observed under microscope and measured using absorbance at 440nm. Assembled polypeptides were also cross-linked to form thin membranes whose mechanical and physical properties were measured and compared. These mutations resulted in markedly different behavior than wild-type elastin-like proteins, suggesting that mutations in the repetitive elements of the elastin sequence can lead to adverse changes in the physical and functional properties of the resulting protein. Using next-generation sequencing, patients with thoracic aortic aneurysms are being genotyped to discover polymorphisms which may adversely affect the self-assembly properties of elastin, providing a link between genetic variation in elastin and cardiovascular disease.

ITC/USA 2014 Conference Proceedings / The Fiftieth Annual International Telemetering Conference and Technical Exhibition / October 20-23, 2014 / Town and Country Resort & Convention Center, San Diego, CA / SOQPSK-TG is a highly bandwidth-efficient constant-envelope modulation so that it has been applied in aeronautical telemetry widely. We develop a simple detection of SOQPSK-TG which is based on a modified OQPSK detection. The simple detection has the advantages of low complexity and good performance. And it's also suitable for other varieties of SOQPSK and FQPSK.

The intricate dependency of networking protocols upon the performance of the wireless channel motivates the investigation of network channel approximations for fading channels. Wireless networking protocols are increasingly being designed and evaluated with the assistance of networking simulators. While evaluating networking protocols such as medium access control, routing, and reliable transport, the network channel model, and its associated capacity, will drastically impact the achievable network throughput. Researcher relying upon simulation results must therefore use extreme caution to ensure the use of similar channel models when performing protocol comparisons. Some channel approximations have been created to mimic the behavior of a fading environment, however there exists little to no justification for these channel approximations. This dissertation addresses the need for a computationally efficient fading channel approximation for use in network simulations. A rigorous flat fading channel model was developed for use in accuracy measurements of channel approximations. The popular two-state Markov model channel approximation is analyzed and shown to perform poorly for low to moderate signal-to-noise ratios (SNR). Three novel channel approximations are derived, with multiple methods of parameter estimation. Each model is analyzed for both statistical performance and network performance. The final model is shown to achieve very accurate network throughput performance by achieving a very close matching of the frame run distributions. This work provides a rigorous evaluation of the popular two-state Markov model, and three novel low complexity channel models in both statistical accuracy and network throughput performance. The novel models are formed through attempts to match key statistical parameters of frame error run and good frame run statistics. It is shown that only matching key parameters is insufficient to achieve an acceptable channel approximation and that it is necessary to approximate the distribution of frame error duration and good frame run duration. The final novel channel approximation, the three-state run-length model, is shown to achieve a good approximation of the desired distributions when some key statistical parameters are matched.

High-Frequency Surface Wave Radar (HFSWR) is a radar technology that offers numerous advantages for surveillance of coastal waters beyond the exclusive economic zone. However, target detection and tracking is primarily limited by ionospheric interference. Ionospheric clutter is characterized by a high degree of nonhomogeneity and nonstationarity, which makes its suppression difficult using conventional processing techniques. Space-time adaptive processing techniques have enjoyed great success in airborne radar, but have not yet been investigated in the context of HFSWR. This thesis is primarily concerned with the evaluation of existing STAP techniques in the HFSWR scenario and the development of a new multistage adaptive processing approach, dubbed the Fast Fully Adaptive (FFA) scheme, which was developed with the particular constraints of the HFSWR interference environment in mind. Three different spatio-temporal partitioning schemes are introduced and a thorough investigation of the performance of the FFA is conducted.

High-Frequency Surface Wave Radar (HFSWR) is a radar technology that offers numerous advantages for surveillance of coastal waters beyond the exclusive economic zone. However, target detection and tracking is primarily limited by ionospheric interference. Ionospheric clutter is characterized by a high degree of nonhomogeneity and nonstationarity, which makes its suppression difficult using conventional processing techniques. Space-time adaptive processing techniques have enjoyed great success in airborne radar, but have not yet been investigated in the context of HFSWR. This thesis is primarily concerned with the evaluation of existing STAP techniques in the HFSWR scenario and the development of a new multistage adaptive processing approach, dubbed the Fast Fully Adaptive (FFA) scheme, which was developed with the particular constraints of the HFSWR interference environment in mind. Three different spatio-temporal partitioning schemes are introduced and a thorough investigation of the performance of the FFA is conducted.