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In many areas of the Western U.S., diffuse knapweed (Centaurea diffusa Lam.) has invaded into plant communities dominated by bluebunch wheatgrass (Pseudomegnaria spicata [Pursh] A. Love). The objectives of this study were to compare growth response of both species when grown under altered moisture and temperature regimes while in the seedling stage and to further elucidate the competitive ability of diffuse knapweed compared to bluebunch wheatgrass. Isolated individuals were grown in four different environmental chamber conditions (12 hr day length, 10 and 16C and -0.01 MPa and -0.03 MPa soil moisture). Diffuse knapweed penetrated quicker than bluebunch wheatgrass starting on day 20, regardless of temperature and moisture and knapweed penetration was greatest under warm and wet soil conditions. Bluebunch wheatgrass developed more root length initially under warmer and drier conditions, but those differences diminished after thirty days growth. Warmer and wetter soil conditions favored diffuse knapweed leaf area production in later stages of seedling growth. Diffuse knapweed had more rapid root penetration than bluebunch wheatgrass under the conditions studied. Diffuse knapweed maximized shoot production, indicative of a relatively fast growing species, while bluebunch wheatgrass maximized root production, characteristic of a relatively slow growing species. Diffuse knapweed seedlings grew best under warmer and wetter conditions. Comparing plant efficiency (indices of plant efficiency based on the measurement of a plant attribute divided by the total biomass of the plant), diffuse knapweed was apparently more efficient than bluebunch wheatgrass at producing the competitive attributes of root penetration, leaf area and root length. / Graduation date: 1998

Skin cancer is the most common form of cancer and it is on the rise. If skin cancer is diagnosed early enough, the survival rate is close to 90%. Oblique-incidence diffuse reflectance (OIR) spectroscopy offers a technology that may be used in the clinic to aid physicians in diagnosing both melanoma and non-melanoma skin cancers. The system includes a halogen light source, a fiber optic probe, an imaging spectrograph, a charge coupled device (CCD) camera, and a computer. Light is delivered to the skin surface via optical fibers in the probe. After interacting with the skin, the light is collected and sent to the spectrograph that generates optical spectra. Images and histopathological diagnoses were obtained from 250 lesions at the University of Texas M.D. Anderson Cancer Center (Melanoma and Skin Center). To classify OIR data, an image processing algorithm was developed and evaluated for both pigmented and non-pigmented lesions. The continuous wavelet transform and the genetic algorithm were employed to extract optimal classification features. Bayes decision rule was used to categorize spatiospectral images based on the selected classification features. The overall classification accuracy for pigmented melanomas and severely dysplastic nevi is 100%. The overall classification accuracy for non-pigmented skin cancers and severely dysplastic nevi is 93.33%. Oblique-incidence diffuse reflectance spectroscopy and the developed algorithms have high classification rates and may prove useful in the clinic as the process is fast, noninvasive and accurate.

This thesis is focused on a study on modeling and measurement of the indoor radio and infrared channels. Both channels have been studied, compared and their vital differences identified. Initially, an infrared channel model was developed that was not similar to any existing models for the infrared domain. The wireless diffuse infrared channel is solely used indoors and is usually confined within a room. Conventional channel models are described, but their disadvantage is heavy time and processor requirements. A new model is introduced, in which the approach is different from the traditional methods in the way that it discretises the delay range instead of the physical characteristics of the environment. The new model offers accurate results without the increased time and processor requirements compared with traditional techniques. Following the characterisation of the infrared channel, a wideband radio propagation campaign took place in two different buildings that allowed valuable insight into the mobile radio channel. Time domain analysis of the measurement results allowed the careful study of the radio channel and produced interesting results as far as RMS delay spread and Power Delay Statistics are concerned. It has been shown that the RMS delay spread is not always dependent on antenna separation, while it was found to be highly dependent on the clutter present on the measurement environment. The infrared model was finally converted to account for radio propagation. Traditional channel models for indoor propagation prediction are described, while the major differences of the infrared and radio channel are mentioned. The radio channel prediction benefits from the accuracy of the infrared model, where a very high accuracy is necessary in order to predict the effect of scattering. A simple measurement campaign has been introduced in order to validate the results of the simulation tool and a comparison with the most important wideband channel models has been performed, along with higher frequency measurements where scattering is more important. The results present a good fit to the measurements and models in the literature, and empirical conclusions relative to the scattering characteristics of the radio channel are drawn from these comparisons.

Lung cancer is the leading cause of death from cancer in Canada and is typically treated with surgical resection of the tumor. To ensure good prognosis and limit metastases no cancer cells can be left behind during resection. This project uses time-resolved fluorescence and diffuse reflectance to differentiate cancerous and non-cancerous lung tissue. These differences could be used during surgical resection of tumor to ensure no positive margins are present. Using a bi-modal spectroscopy device, BEAR, optical properties were determined for 36 tumor, 36 fibrotic and 9 normal lung tissue samples. Most optical parameters showed statistically significant differences between tumor and other tissue types. Metabolic based optical parameters showed statistically significant differences between fibrotic and normal tissue while non-metabolic based parameters showed no difference. As surgical margins are likely to be between tumor and fibrotic tissue the results demonstrate success and promise for implementing this system. Future work using fresh samples would develop the system further and would be a step closer to in vivo use during surgery. / Thesis / Master of Science (MSc) / Lung cancer is the leading cause of death from cancer and is typically treated by surgically removing the tumor. To improve survival all cancer cells must be removed which can be challenging. This project uses light to extract properties that can differentiate cancerous and non-cancerous lung tissue. These differences could be used during surgery to ensure no cancer cells remain. The project tests this system on 36 tumor, 36 fibrotic and 9 normal lung tissue samples. Most parameters showed significant differences between tumor and other tissue types. Given that often times the surgical boundaries are between tumor and fibrotic tissue the results demonstrate promise in implementing this system. Future work using fresh samples would develop the system further and bring it one step closer to being used during surgery.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / This paper discusses an error-correcting scheme applied to a telemetry system over HF radio channel. According to the statistical properties of transmission error on HF radio channel, the scheme uses one important diffuse convolutional code, which is threshold decoded and corrects the random or burst errors. The operation of this code is explained, and a new method for word synchronization and bit synchronization is proposed. Coding and decoding, word synchronization, and bit synchronization are all activated by software program so as to greatly improve the flexibleness and applicability of the data transmission system. Test results of error-correcting are given for a variety of bit-error-rate (BER)s on HF radio channel.

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