The main aim of this thesis is to study the effects of using a reduced level of arithmetical precision (as found in a 16-bit microprocessor) whilst running various algorithms in the detection stages of a digital modem. The reason for using a lower precision is to see if these algorithms will run on a limited precision device, such as a Texas Instruments TMS320C25 digital signal processor, in real time.

The major theme of Hemingway's last novel, Islands in the Stream, is the moral and spiritual development of the protagonist, Thomas Hudson. Gradually he moves away from his "carapace of work" and discipline, which shields him from any emotional involvement and the inevitable pain it contracts, towards an acceptance of a higher concept of duty than that which is concerned primarily with practical results. In this way he grows from a state of emotional alienation to a point at which he attains a genuine capacity to love his fellow men. This growth culminates with his encounter with death whereby he comes to an understanding of himself and of his purpose in life. I have traced his development by examining several themes and motifs which reflect his emotional state. The most important of these is the pervasive sea imagery which changes with Hudson's changing moral attitude. The basic sea-chase in the last section of the novel is really an allegory which represents, on a metaphorical level, Hudson's personal quest inward for self-knowledge. Hudson's relationship in various families, some natural and some surrogate, also reflects his growing capacity to love and to establish the necessary emotional found ation for a real family situation. He grows from an inability to under stand his natural sons to a capacity to love his spiritual brothers. Another motif of a "language of love" also develops in accordance with Hudson'8 growth. At the end of the novel, with Hudson's death, these themes and motifs coalesce with the culmination of Hudson's symbolic crucifixion and marriage-in-death. In my conclusion I am primarily interested in proving that Hudson final understanding of himself, and his struggle towards it, is as worthy as the absolute achievements of earlier Hemingway heroes. His growth is not obvious to many reviewers simply because his heroism is based upon a different concept than that of past Hemingway protagonists. Thomas Hudson is different in that his struggle with life resembles that of the average man, and like the average man he must learn to accept his flaws and weaknesses, and to accept "approximate" successes instead of absolute victories. / Arts, Faculty of / English, Department of / Graduate

Stormflow generation was studied in a two square kilometre, sub-alpine, first-order basin tributary to Ryan River, which is in the Pacific Ranges of the Coast Mountains of British Columbia. Preliminary field work suggested that neither saturation overland flow nor subsurface stormflow were important mechanisms of stormflow generation Hortonian overland flow appeared to be dominant. The infiltrability of the soils dropped considerably during storm events. Three possible causes of this decline were considered initially: (1) a reduction in capillary gradients as wetting proceeds, (2) a textural contrast in the profile, and (3) air entrapment. All of the preceeding were rejected on the basis of more detailed observations. Instead, it was proposed that a water-repellent layer existed near the top of the soil profile. Laboratory experiments conducted on intact soil samples demonstrated that a repellent layer on the order of a few centimetres thickness did exist near the soil surface. The implications of this finding for infiltration and stormflow generation are discussed. / Arts, Faculty of / Geography, Department of / Graduate

Patterns of in-stream summer transport of total dissolved nitrogen (TDN) and total dissolved phosphorus (TDP) in a high gradient second order stream in southwestern British Columbia were described. Some biological, physical, and chemical processes were also identified and evaluated with respect to their role in regulating in-stream transport of TDN and TDP. Fifteen water sampling stations were established along an alternating series of open clearcut and densely forest covered drainage areas, each several hundred metres in length. These drainage sections represented young and midsuccessional ecosystems. The furthest upstream section (which was forest covered) and an adjacent downstream open clearcut section each had weirs which were used for comparisons of TDN and TDP export between the successionally different systems. Export of TDN was consistently lower from the clearcut section than from the upstream forested section. This indicated that there was consistent in-stream absorption of TDN within the clearcut section. Nitrate flux dominated the absorption of TDN. A pairing analysis of precutting nitrate export data from 1972 with post-treatment export data from 1979 indicated that the absorption of nitrate was due to increased solar radiation reaching the stream channel. It was proposed that the increased light inputs which provided an additional energy input to the stream ecosystem, increased nitrate spiralling rates. Without disruptive stormflow events the net effect was a retention of nitrate within the stream. Concentrations of TDP were often less than detectable limits so comparisons of P export could not be made. The TDN data suggested that if nutrient absorption in small watershed streams is widespread, nutrient retention on land may have been overestimated in past small watershed nutrient budget studies. A further analysis of downstream flux in element concentrations was conducted for all forms of TDN and TDP using three-dimensional images (distance downstream x time x element concentration) from data collected in summer 1979. Nitrate concentrations consistently declined in open sections but increased in densely forest covered sections. Trends in ammonium concentrations were difficult to detect. Orthophosphate levels were rarely greater than the detectable limit of 3 ug/1 in all sections. Dissolved organic nitrogen (DON) and dissolved organic phosphorus (DOP) flux was highly variable with no apparent trend. Nutrient spiralling processes were proposed to explain the flux of each of these forms of TDN and TDP. An enrichment experiment conducted in a clearcut section of the study stream in mid-summer indicated that rates of disappearance of N0₃⁻-N, NH₄⁺-N, and HP0₄⁻²-P from solution were directly related to element concentrations in solution and that relationship could be expressed as fourth, first, and third degree polynomials respectively. Disappearance rates of the three ions were in the order NH₄⁺-N> HP0₄⁻²--P> N0₃⁻-N. Reasons for the differences in disappearance rates between elements and element forms were proposed. The first end-of-summer storm event produced a 20-fold increase in stream discharge at peak flow over summer base flow. This resulted in a 10-fold increase in N0₃⁻-N concentrations in all stream sections. The increased loading was attributed to flushing of N0₃⁻-N from land. Stream power was not destructive, however, and N0₃⁻-N removed from solution increased over that during summer base flow. The increased uptake rates were attributed to an increase in active nutrient processing areas of the stream substrate. DON and DOP concentrations and export increased during the storm but NH₄⁺-N and HPO₄⁻²-P concentrations did not change. Again, detailed explanations for this element behaviour were proposed. Results of an enrichment experiment designed to evaluate the role of periphyton in regulation of nutrient transport were insufficient to fully assess the quantitative role of periphyton. Hypotheses were proposed, however, to further evaluate the role of periphyton using alternative methods. Concluding hypotheses were presented to aid in the development of future research plans. / Forestry, Faculty of / Graduate

Indiana University-Purdue University Indianapolis (IUPUI) / Data network's speed and availability are increasing at a record rate. More and more devices are now able to connect to the Internet and stream data. Processing this ever-growing amount of data in real time continues to be a challenge. Multiple studies have been conducted to address the growing demands for real-time processing and analysis of continuous data streams. Developed in a previous work, Symbiote Coprocessor Unit (SCU) is a hardware accelerator capable of providing up to 150X speedup over traditional data stream processors in the field of data stream management systems. However, SCU implementation is very complex, fixed, and uses an outdated host interface, which limits future improvements. In this study, we present a new SCU architecture that is based on a Xilinx MicroBlaze configurable microcontroller. The proposed architecture reduces complexity, allows future implementations of new algorithms in a relatively short amount of time while maintaining the SCU's high performance. It also has an industry standard PCIe interface. Finally, it uses a standard AMBA AXI4 bus interconnect, which enables easier integration of new hardware components. The new architecture is implemented using a Xilinx VC709 development board. Our experimental results have shown a minimal loss of performance as compared to the original SCU while providing a flexible and simple design.

Flow information is necessary in many diverse applications including water supply management, pollution control, irrigation, flood control, energy generation, and industrial use. New technologies have been developed for the establishment of stage-discharge relationships due to concerns about costs, accuracy, and safety of traditional discharge estimation methods. One emerging technology for measuring open-channel flow is Large-Scale Particle Image Velocimetry (LSPIV). LSPIV is a system capable of measuring surface velocity by collecting and analyzing recorded images of the stream surface. LSPIV has several advantages over conventional discharge measurement techniques: LSPIV is safer, could be automated to reduce labor, and could produce "real-time" discharge measurements. Therefore, the overall goal of this study was to evaluate the accuracy and feasibility of using LSPIV to measure discharge in low-order streams. The specific goals were to develop and test a prototype under varying conditions in a laboratory flume, adapt the prototype for field conditions, test the accuracy of the prototype in the field, and assess and recommend improvements for LSPIV operation as a stream discharge measuring device. The laboratory experiments results indicated that LSPIV accuracy was influenced by camera angle, surface disturbances and flow regime (Froude number), and particle seeding density. Camera angle was optimum around 15 degrees, with larger camera angles producing more error due to image distortion. Conditions at high Froude numbers likely produced out-of-plane displacement losses due to surface disturbances. Low Froude numbers also showed under-predictions, which were likely due to agglomeration of the tracer particles at low velocities. Finally, the laboratory results demonstrated that tracer seeding density should be maximized and that densities below three particles per interrogation window should significantly reduce LSPIV accuracy. The LSPIV prototype was tested at two low-order streams after developing a field prototype and operating procedures. Under field conditions, the prototype acquired consistent images, performed the necessary image processing, and established rules for estimating input parameters. The accuracy of LSPIV was evaluated using a Flo-Mate 2000 current meter and a permanent weir. Overall, twenty discharge measurements were taken with each measuring device at Stroubles Creek and Crab Creek. The discharges measured ranged from 0.12 to 63 cfs, which corresponded to a large range of velocities, with both simple and complex flow patterns. Problems were encountered from surface glare reducing image quality at both sites. The LSPIV prototype was accurate for most measuring conditions with a mean error of -1.7%, compared to the weir measurements. The LSPIV measurements tended to under-predict discharge at high stages and had greater error at moderate flows (up to 39%) compared to the weir. However, at low flow conditions LSPIV showed improved discharge accuracy over the current meter, in comparison to the weir measurements. The LSPIV discharge measurements were not statistically different from either the current meter or weir (á = 0.05). Finally, the LSPIV discharge measurements had an uncertainty of approximately ±14% (at a 95% confidence interval). In conclusion, LSPIV accuracy can be degraded by surface disturbances, inadequate illumination, and poor seeding densities. However, LSPIV showed adequate accuracy with the potential to become competitive with conventional discharge measurement techniques and therefore, has the potential to reduce costs and increase the geographic extent of surface water monitoring networks. / Master of Science

The U.S. Geological Survey started measuring stream flow in 1888 as part of a public land irrigation study. The demand for accurate stream flow measurement has increased with the rising concern about nonpoint source (NPS) pollution. NPS pollution studies, such as TMDL development, often involve quantification of flow in small first and second order streams. This application of technology intended for use in larger streams presents special problems that must be addressed by the user. The goal of this study was to conduct a comparative analysis of the current technologies used to measure flow in small streams with respect to accuracy and cost. The analyses involved field investigations, laboratory experiments, and a cost analysis. The specific study objectives were: 1) Compare the accuracy of various methods for estimating stream discharge in small first and second order streams, 2) Compare the accuracy of various methods for estimating stream discharge in a controlled laboratory environment, and 3) Evaluate the costs associated with installation, operation, and maintenance of each of the systems investigated. Ten stream-gaging methods were evaluated for their field performance, laboratory performance, and costs. Analysis of the field investigation data indicated that the Marsh McBirney current meter and the One-orange method were the most accurate among the methods studied. The results of the laboratory experiments imply that the Starflow acoustic Doppler and Valeport BFM001 current meter performed best among the ten methods. The Starflow acoustic Doppler device also proved to be the most cost-effective method. Overall, the Marsh McBirney and Valeport BFM001 current meters exhibited the best performance for both field and laboratory situations among the methods evaluated. / Master of Science

Connectivity in ecological systems is a broad concept that embodies the transmission of ecosystem components throughout landscapes at multiple spatial and temporal scales. Of relevance to the present study are the connections (or lack thereof) among local populations of stream fauna - population connectivity in lotic systems. Dispersal, recolonisation and migration are the demographic forms of population connectivity, and gene flow is the genetic aspect of population connectivity. Both forms of population connectivity have underpinned some of the classic theories and hypotheses in stream ecology, and have implications for pure and applied stream ecology, including ecosystem restoration. Conceptual models in ecology can facilitate understanding and predictability of the ecosystem processes they represent, and have potential applicability as management tools or 'rules of thumb' in conservation and restoration programs. Various theoretical models describe potential patterns of connectivity among local populations and in this thesis these models were used to evaluate population connectivity in a freshwater fish (southern pygmy perch, Nannoperca australis) and two reproductively isolated genetic lineages of freshwater shrimp (Paratya spp.) in small, geomorphically degraded streams in south eastern Australia. These streams (the Granite Creeks) have been the focus of a recent habitat restoration trial and several studies have examined fish and macroinvertebrate community responses to the experiment. It was the purpose of this study to contribute information about population connectivity in the selected species to complement these community ecology studies. Population connectivity was examined in these species using molecular data (mitochondrial and nuclear genetic data) and natural abundance isotopic signatures of nitrogen and carbon. At the landscape scale, results showed that populations of N. australis and the P. australiensis lineages were isolated among the streams and among sites within streams, and that there was no consistent pattern of isolation-by-distance in genetic data for any species. Thus, classic models of population connectivity, such as the Island Model and Stepping-Stone Model, were not supported by this study. Results indicated that population models that incorporated more complex aspects of stream structure may be more appropriate than these classic models for approximating observed patterns of population connectivity in lotic systems. The Stream Hierarchy Model (SHM) predicts that the hierarchical aspect of stream structure (i.e. stream confluences) have a dominant role in shaping patterns of population connectivity in lotic fauna, whereby populations among streams are more isolated than those within them. Although stream confluences were found to have an important role in population subdivision for the species examined in this study, the expectations of the SHM were met for only N. australis. For the P. australiensis lineages, the influence of topography (i.e. the longitudinal aspect of stream structure) was just as important as stream confluences in isolating local populations. Large-scale determinants of population isolation were thus found to be associated with both the hierarchical and longitudinal aspects of stream structure, and were not well represented by any single theoretical model of population connectivity. At within-stream scales, upland populations tended to be extremely isolated from other populations and had temporally stable genetic signatures. In contrast, lowland populations were connected to other lowland populations within the same stream to a greater degree, although the connections were patchy and a slight signature of temporal instability in the genetic data was evident for one of the P. australiensis lineages. Thus, metapopulation or patchy population models were found to represent connections among lowland populations within the same stream, although they were not appropriate for describing connectivity among upland populations. This finding highlights the importance of the longitudinal aspect of stream structure in shaping ecological patterns in lotic systems, and demonstrates that local patterns of population connectivity can vary over relatively small spatial scales. Overall, the results illustrate that both hierarchical and longitudinal aspects of stream structure can have important roles in isolating populations of stream fauna. They therefore also represent constraints for the ability of aquatic fauna to colonise restored habitat in streams. The corollary of this, however, is that such isolated populations of stream fauna represent appropriate population units at which to target habitat restoration. The hierarchical and longitudinal aspects of stream structure may thus represent 'rules of thumb' or 'landscape filters' that stream restoration ecologists could use to predict likely isolated populations of lotic fauna across the landscape. Such a 'rule of thumb' might be the inclusion of multiple isolated population units in restoration programs, as this strategy is likely to generate the greatest biological response to the restoration at the landscape scale, particularly with respect to intra-specific genetic diversity captured by restoration. At small spatial scales, such as for a single stream or tributary, the longitudinal aspect of stream structure can be an important factor to consider when designing stream habitat restoration programs. In this study, lowland sites were unstable and there were patchy connections among local lowland populations within the same stream, whereas upland populations were isolated at this scale. In contrast, other studies have found that upstream populations of some species can be connected in a patchy fashion in other systems. For such unstable sections of stream, where there are patchy patterns of local population connectivity, the inclusion of multiple restored patches, especially refugial habitat, is likely to produce the greatest biotic response at the patch scale, particularly with respect to demographic responses (such as local colonisation). Multiple restored refugial patches will enable species to persist throughout the stream section during adverse environmental conditions, will allow for variation in local movement patterns and distances between species and between years with contrasting environment conditions (e.g. stream flow), and may harbour different species assemblages and intraspecific genotypes due to stochastic processes (i.e. have functional heterogeneity). The hierarchical and longitudinal aspects of stream structure are thus important determinants of population connectivity at both large and small spatial scales, and have implications for how stream biota will respond to restoration at patch and landscape scales.

Published literature about six Pacific Northwest stream systems was contrasted to provide a regional perspective on channel response to disturbance. This investigation was prompted by a combination of recent environmental legislation, mounting social pressures to plan projects at a drainage basin scale, and the difficulty in defining and predicting the response and recovery of a stream channel to land-use management or storm events. Detailed studies of Redwood Creek, CA; the San Lorenzo River, CA; the South Fork Salmon River, ID; the Upper Middle Fork of the Willamette River, OR; the Alsea River System, OR; and Carnation Creek, B.C. were reviewed and contrasted. Differences in channel response to disturbance appear to be the result of the sequence of storms, the interactions between storms and land-use, the processes that deliver sediment to the channel, the available stream power, and the bank stability. Basins with low debris avalanche and earthflow potential, high stream power, and stable stream banks experience only localized and short-lived response to disturbance. On the other hand, basins with frequent debris avalanches or high earthflow potential and unstable banks experience widespread and persistent response. This study concludes that there must be realization and acceptance of the random nature of channel response and recovery following disturbance. Field evaluation, professional judgement, risk assessment, and adaptive management are the most powerful tools available in the prediction of channel response. / Graduation date: 1993

Thesis (Ph. D.)--Virginia Polytechnic Institute and State University, 2001. / Title from PDF title page (viewed on Apr. 2, 2005). Vita. Includes bibliographical references (p. 107-121).