An ad hoc network is a collection of mobile wireless devices that cooperate with each other to route packets amongst themselves. The main difficulty in designing routing algorithms for such a network is the large number of topology changes that the network undergoes due to device movement. Selective flooding is a routing technique that is more resilient to topology changes than traditional algorithms but is more bandwidth efficient than pure flooding. An on-demand selective flooding algorithm has been designed and tested on the ns-2 simulator. In scenarios involving a large number of topology changes, selective flooding outperforms other ad hoc network routing techniques. Unfortunately, selective flooding is much more bandwidth hungry and is unable to scale to handle reasonable traffic loads. Interestingly, the analysis of selective flooding reveals major problems with traditional ad hoc networking techniques. Many current algorithms demonstrate shortcomings when dealing with bursty traffic, and current wireless hardware cannot handle ad hoc networking traffic in an efficient manner. These issues need to be addressed before ad hoc networking technology can become feasible for widespread use.

One of the world’s largest freshwater deltas (~4000 km2), the Peace-Athabasca Delta (PAD), is located at the convergence of the Peace and Athabasca rivers and Lake Athabasca in northern Alberta, Canada. Since the early 1970s, there has been increasing concern regarding the ecological impacts on the PAD after flow regulation of the Peace River began in 1968, decreased discharge in the Peace and Athabasca rivers as a result of hydroclimatic changes in Western Canada, and increased Athabasca River water usage by oil sands development to the south. This thesis is part of an ongoing, multi-disciplinary project assessing current and past hydrological and ecological conditions in the PAD. Research conducted in this thesis aims to better understand the processes controlling water balance of lakes in the PAD using mainly stable water isotope data collected from lakes and their input sources. Isotope data are used to describe and quantify hydrological processes for individual lakes (seasonal and annual) and across the delta and are supported by other chemical and hydrometric data. An isotopic framework in d18O-d2H-space is developed for the PAD using evaporation-flux-weighted local climate data, and isotopic data collected from a reference basin, lakes throughout the PAD, and lake input sources (i.e., snowmelt, rainfall, and river water). The framework is comprised of two reference lines, the Local Meteoric Water Line, which is based on measured isotopic composition of precipitation, and the Local Evaporation Line, which is based on modelled isotopic composition of reference points. Evaporation pan data is used to assess short-term variations in key isotopic reference values, which are important for addressing short-term changes in the isotopic signature of shallow basins. This framework is used in subsequent chapters including assessment of seasonal and annual water balance of two hydrologically-contrasting shallow lakes, and to quantify the impacts of flood water and snowmelt on a set of 45 lakes in spring 2003. Five years of isotope data using time-series analysis and the isotopic framework suggested that a perched (isolated) lake and its catchment (forest and bedrock) in the northern, relict Peace sector captured sufficient rain, snow, and runoff to maintain a relatively stable water balance, and also that a low-lying lake in the southern, active Athabasca sector was regularly replenished with river water in both spring and summer. Snowmelt and rainfall were found to have diluted the perched basin by an average of 16% and 28 % respectively, while spring and summer floods were found to almost completely flush the low-lying lake. Using the spring 2003 regional dataset, flooded lakes were separated from snowmelt-dominated lakes through use of suspended sediment concentrations, isotope data, and field observations. Application of an isotope mixing model translated d18O values into a range of replenishment amount by either river water or snowmelt, which compared well with hydrological conditions at the time of sampling and previously classified drainage types of the lakes. Spatial mapping of replenishment amounts illustrated flooding of much of the Athabasca sector due to ice-jams, except for two sub-regions isolated from flooding by artificial and natural northern diversion of flow from the Athabasca River. It is also shown that most of the relict landscape of the Peace sector was replenished by snowmelt except for a few low-lying lakes close to the Peace River and its tributaries. Overall, improved understanding of lake and regional hydrology in the PAD, especially the ability to quantify the affects of various lake inputs, will improve the ability to develop effective guidelines and management practices in the PAD as lakes respond to future changes in climate and river discharge.

An ad hoc network is a collection of mobile wireless devices that cooperate with each other to route packets amongst themselves. The main difficulty in designing routing algorithms for such a network is the large number of topology changes that the network undergoes due to device movement. Selective flooding is a routing technique that is more resilient to topology changes than traditional algorithms but is more bandwidth efficient than pure flooding. An on-demand selective flooding algorithm has been designed and tested on the ns-2 simulator. In scenarios involving a large number of topology changes, selective flooding outperforms other ad hoc network routing techniques. Unfortunately, selective flooding is much more bandwidth hungry and is unable to scale to handle reasonable traffic loads. Interestingly, the analysis of selective flooding reveals major problems with traditional ad hoc networking techniques. Many current algorithms demonstrate shortcomings when dealing with bursty traffic, and current wireless hardware cannot handle ad hoc networking traffic in an efficient manner. These issues need to be addressed before ad hoc networking technology can become feasible for widespread use.

Periodic flooding has been widely believed to serve an important role in maintaining water levels and productivity of aquatic basins in floodplain landscapes. Here, I analyze four basins of contrasting flood frequencies (one through-flow, one pulse-flooded, two non-flooded) and two adjacent river sites in the PAD were sampled during the open-water season of 2007 and spring of 2008 to characterize linkages between hydrological processes (using O and H stable isotopes) and limnological conditions, and to assess how these linkages affect trophic interactions involving the aquatic flora and fauna (using C and N stable isotopes). The water balance and water chemistry of the through-flow basin was dominated at all times by the input of river water which reduced concentrations of nutrients and ions. In contrast, evaporation played an important role in the water balance and concentrated nutrients and ions in the non-flooded basins. Surprisingly, pulse-flood events had short-lived effects on the water balance and carbon stable isotopic signatures of biota. Hydrological and limnological conditions in the pulse-flooded basin were similar to those of the river water shortly after spring flooding. After flooding, evaporation caused rapid increase of δ18O of the water comparable to patterns observed in the non-flooded basins, but recovery of water chemistry variables was delayed. In the non-flooded and pulse-flooded basins, δ13CDIC declined due to atmospheric CO2 invasion under conditions of high primary productivity and pH that generated strong kinetic fractionation. This decline in δ13CDIC values produced the opposite effect compared to when photosynthesis occurs under non-limiting carbon conditions, as occurred in the through-flow basin. This feature provides important new knowledge to improve paleolimnological interpretation of δ13C values of organic matter in sediment cores to track past changes in flooding regimes. Importantly, this study shows that pulse floods exert short-lived transient (~1-2 months) effects of the water balance and carbon dynamics of aquatic food-webs and do not elevate aquatic production, but exert longer lasting (at least an entire open-water season) on water chemistry conditions. This contrasts with previous beliefs that the effects of pulse flooding are more profound and longer lasting.

This minor field study has explored what factors cause vulnerability to community members living in informal settlements exposed to localized urban flooding. Particularly, the effects of flooding that women living in Bwaise Parish III, Kampala, Uganda have to encounter were studied. Eight weeks were spent in Kampala, Uganda for field work, which included interviews and a workshop with community members from Bwaise Parish III, interviews with scientists at Makerere University and thesis writing. Generally, small-scale disasters surface because of poor urban management. The results showed that inadequate urban planning was affecting the poor that were living on marginal lands. Bwaise Parish III had emerged on a location that was both hazardous and unhealthy. The analysis showed that poor people were limited in their options of risk limitation because of their lack of basic capabilities. Women in Bwaise Parish III were affected by flooding directly and indirectly through the loss of livelihoods and belongings and through time spent getting water out of their houses. Women were generally disproportionally affected by flooding because of their vulnerabilities such as lower socioeconomic status and responsibilities that confined them to their homes. The way forward in order to mitigate localized flooding impacts would entail reducing vulnerabilities, strengthening capabilities and developing infrastructure. / Denna Minor Field Study har undersökt vilka faktorer som orsakar sårbarheter för samhällsmedlemmar som bor i informella bosättningar som exponeras av småskaliga  översvämningar. Det som studerades var effekterna av dessa översvämningar och hur kvinnor i Bwaise Parish III i Kampala, Uganda drabbades. Åtta veckor tillbringades i Kampala för fältarbete som innehöll intervjuer och en workshop med samhällsmedlemmar från Bwaise Parish III, intervjuer med forskare vid Makerere Univeritetet samt uppsatsskrivande. Generellt sätt så brukar småskaliga katastrofer uppstå på grund av dålig stadsförvaltning. Resultaten visade att bristande stadsplanering påverkade de fattiga som levde på marginella marker och att Bwaise Parish III låg på en plats som var både farlig och ohälsosam. Analysen visade att fattiga människor var begränsade i sina möjligheter att minska sina risker på grund av att de saknade grundläggande förutsättningar. Kvinnor i Bwaise Parish III påverkades av översvämningar både direkt och indirekt genom förlusten av försörjningsmöjligheter och tillhörigheter och genom att de var tvungna att spendera tid med att få bort vatten från deras hem. I allmänhet drabbas kvinnor oproportionerligt av översvämningar på grund av deras sårbarhet såsom lägre socioekonomisk status och ansvar som begränsar dem till deras hem. Vägen framåt för att minska småskaliga översvämningar och konsekvenser skulle innebära att minska sårbarheten för samhällsmedlemmarna, öka deras förutsättningar och utveckla en fungerande infrastruktur.

Chemical EOR processes such as polymer flooding and surfactant polymer flooding must be designed and implemented in an economically attractive manner to be perceived as viable oil recovery options. The primary expenses associated with these processes are chemical costs which are predominantly controlled by the crude oil properties of a reservoir. Crude oil viscosity dictates polymer concentration requirements for mobility control and can also negatively affect the rheological properties of a microemulsion when surfactant polymer flooding. High microemulsion viscosity can be reduced with the introduction of an alcohol co-solvent into the surfactant formulation, but this increases the cost of the formulation. Experimental research done as part of this study combined the process of hot water injection with ASP flooding as a solution to reduce both crude oil viscosity and microemulsion viscosity. The results of this investigation revealed that when action was taken to reduce microemulsion viscosity, residual oil recoveries were greater than 90%. Hot water flooding lowered required polymer concentrations by reducing oil viscosity and lowered microemulsion viscosity without co-solvent. Laboratory testing of viscous microemulsions in core floods proved to compromise surfactant performance and oil recovery by causing high surfactant retention, high pressure gradients that would be unsustainable in the field, high required polymer concentrations to maintain favorable mobility during chemical flooding, reduced sweep efficiency and stagnation of microemulsions due to high viscosity from flowing at low shear rates. Rough scale-up chemical cost estimations were performed using core flood performance data. Without reducing microemulsion viscosity, field chemical costs were as high as 26.15 dollars per incremental barrel of oil. The introduction of co-solvent reduced chemical costs to as low as 22.01 dollars per incremental barrel of oil. This reduction in cost is the combined result of increasing residual oil recovery and the added cost of an alcohol co-solvent. Heating the reservoir by hot water flooding resulted in combined chemical and heating costs of 13.94 dollars per incremental barrel of oil. The significant drop in cost when using hot water is due to increased residual oil recovery, reduction in polymer concentrations from reduced oil viscosity and reduction of microemulsion viscosity at a fraction of the cost of co-solvent. / text

This study is to establish a binomial lattice method to apply real options theory to valuation and decision making in the petroleum exploration and production industry with a specific focus on the switching time from primary to water flooding oil recovery. First, West Texas Intermediate (WTI) historical oil price evolution in the past 25 years is studied and modeled with the geometric Brownian motion (GBM) and one-factor mean reversion price models to capture the oil price uncertainty. Second, to conduct real options evaluation, specific reservoir simulations are designed and oil production profile for primary and water flooding oil recovery for a synthetic onshore oil reservoir is generated using UTCHEM reservoir simulator. Third, a cash flow model from producing the oil reservoir is created with a concessionary fiscal system. Finally, the binomial lattice real options evaluation method is established to value the project with flexibility in the switching time from primary to water flooding oil recovery under uncertain oil prices. The research reaches seven conclusions: 1) for the GBM price model, the assumptions of constant drift rate and constant volatility do not hold for WTI historical oil price; 2) one-factor mean reversion price model is a better model to fit the historical WTI oil prices than the GBM model; 3) the evolution of historical WTI oil prices from January 2, 1986 to May 28, 2010 was according to three price regimes with different long run prices; 4) the established real options evaluation method can be used to identify the best time to switch from primary to water flooding oil recovery using stochastic oil prices; 5) with the mean reversion oil price model and the most updated cost data, the real options evaluation method finds that the water flooding switching time is earlier than the traditional net present value (NPV) optimizing method; 6) the real options evaluation results reveals that most of time water flooding should start when oil price is high, and should not start when oil price is low; and 7) water flooding switching time is sensitive to oil price model to be used and to the investment and operating costs. / text

Preliminary reconnaissance undertaken in summer 2013 identified the scale of stormwater management issues in Xiamen, having frequent storm events that overwhelm the stormwater and sewer infrastructure resulting in widespread flooding. This research explored the role that green facilities play in addressing stormwater issues through the inquiry of Low Impact Development strategies and techniques. From a long-term perspective, green infrastructure planning and implementation is inevitably linked with strong education programs, rational stormwater codes and regulations, a variety of financing and incentives, as well as an integrated and competent administration system. This research presents a design proposal for green infrastructure retrofit for a selected study block in the central area of Xiamen to help guide water sensitive urban design and development in the future. Seven recommendations based on the synthesis of the literature review, key-informant interviews, built-project studies and the retrofit design proposal are proposed. This document will be submitted to Xiamen Urban Planning & Design Institute for considerations to be integrated in city master planning policy and zoning codes and standards as needed and to inform a demonstration project to help advance long-term strategies and recommendations. / October 2015

The performance of Enhanced Oil Recovery (EOR) processes is adversely affected by the heterogeneous distribution of flow properties of the rock. The effects of heterogeneity are further highlighted when the mobility ratio between the displacing and the displaced fluids is unfavorable. Polymer flooding aims to mitigate this by controlling the mobility ratio resulting in an increase in the volumetric swept efficiency. However, the design of the polymer injection process has to take into account the uncertainty due to a limited knowledge of the heterogeneous properties of the reservoir. Numerical reservoir models equipped with the most updated, yet uncertain information about the reservoir should be employed to optimize the operational settings. Consequently, the optimal settings are uncertain and should be revised as the model is updated. In this report, a feedback-control scheme is proposed with a model updating step that conditions prior reservoir models to newly obtained dynamic data, and this followed by an optimization step that adjusts well control settings to maximize (or minimize) an objective function. An illustration of the implementation of the proposed closed-loop scheme is presented through an example where the rate settings of a well affected by water coning are adjusted as the reservoir models are updated. The revised control settings yield an increase in the final value of the objective function. Finally, a fast analog of a polymer flooding displacement that traces the movement of random particles from injectors to producers following probability rules that reflect the physics of the actual displacement is presented. The algorithm was calibrated against the full-physics simulation results from UTCHEM, the compositional chemical flow simulator developed at The University of Texas at Austin. This algorithm can be used for a rapid estimation of basic responses such as breakthrough time or recovery factor and to provide a simplified characterization the reservoir heterogeneity. This report is presented to fulfill the requirements to obtain the degree of Master of Science in Engineering under fast track option. It summarizes the research proposal presented for my doctorate studies that are currently ongoing. / text

Polymer flooding is economically successful in reservoirs where the water flood mobility ratio is high, and/or the reservoir heterogeneity is adverse, because of the improved sweep resulting from the mobility-controlled oil displacement. The performance of a polymer flood can be further improved if the process is dynamically controlled using updated reservoir models and a closed-loop production optimization scheme is implemented. However, the formulation of an optimal production strategy is based on uncertain production forecasts resulting from uncertainty in spatial representation of reservoir heterogeneity, geologic scenarios, inaccurate modeling, scaling, just to cite a few factors. Assessing the uncertainty in reservoir modeling and transferring it to uncertainty in production forecasts is crucial for efficiently controlling the process. This dissertation presents a feedback control framework that (1) assesses uncertainty in reservoir modeling and production forecasts, (2) updates the prior uncertainty in reservoir models by integrating continuously monitored production data, and (3) formulates optimal injection/production rates for the updated reservoir models. This approach focuses on assessing uncertainty in reservoir modeling and production forecasts originated mainly by uncertain geologic scenarios and spatial variations of reservoir properties (heterogeneity). This uncertainty is mapped in a metric space created by comparing multiple reservoir models and measuring differences in effective heterogeneity related to well connectivity and well responses characteristic of polymer flooding. Continuously monitored production data is used to refine the uncertainty map using a Bayesian inversion algorithm. In contrast to classical approach of history matching by model perturbation, a model selection problem is implemented where highly probable reservoir models are selected to represent the posterior uncertainty in production forecasts. The model selection procedure yields the posterior uncertainty associated with the reservoir model. The production optimization problem is solved using the posterior models and a proxy model of polymer flooding to rapidly evaluate the objective function and response surfaces to represent the relationship between well controls and an economic objective function. The value of the feedback control framework is demonstrated with two examples of polymer flooding where the economic performance was maximized. / text