This thesis contains three articles. The first two concern inversion andlocal injectivity of the weighted Radon transform in the plane. The thirdpaper concerns two of the key results from compressive sensing.In Paper A we prove an identity involving three singular double integrals.This is then used to prove an inversion formula for the weighted Radon transform,allowing all weight functions that have been considered previously.Paper B is devoted to stability estimates of the standard and weightedlocal Radon transform. The estimates will hold for functions that satisfy an apriori bound. When weights are involved they must solve a certain differentialequation and fulfill some regularity assumptions.In Paper C we present some new constant bounds. Firstly we presenta version of the theorem of uniform recovery of random sampling matrices,where explicit constants have not been presented before. Secondly we improvethe condition when the so-called restricted isometry property implies the nullspace property. / <p>QC 20140228</p>

Due to the great increase in motor vehicle traffic, the provision of highways, roads, streets and bridges has become a most important function of government at the present time. Complications arise because the vehicles using the public roads are privately owned and operated. [...]

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Availability of precipitation data is very important in every aspect related to hydrology. Readings from the ground stations are reliable and are used in hydrological models to do various analysis. However, the predictions are always associated with uncertainties due to the limited number of ground stations, which requires interpolation of the data. Meanwhile, groundbreaking approach in capturing precipitation events from vantage point through satellites in space has created a platform to not only merge ground data with satellite estimates to produce more accurate result, but also to find the data where ground stations are not available or scarcely available. Nevertheless, the data obtained through these satellite missions needs to be verified on its temporal and spatial resolution as well as the uncertainties associated before we make any decisions on its basis. This study focuses on finding and evaluating data obtained from two multi-satellite precipitation measurements missions: i) Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) ii) Global Precipitation Measurement (GPM) mission. GPM is the latest mission launched on Feb 28, 2014 after the successful completion of TRMM mission which collected valuable data for 17 years since its launch in November 1997. Both near real time and final version precipitation products for TMPA and GPM are considered for this study. Two study areas representing eastern and western parts of the United States of America (USA) are considered: i) Charlotte (CLT) in North Carolina ii) San Francisco (SF) in California. Evaluation is carried out for daily accumulated rainfall estimates and single rainfall events. Statistical analysis and error categorization of daily accumulated rainfall estimates were analyzed in two parts: i) Ten yeas data available for TMPA products were considered for historical analysis ii) Both TMPA and GPM data available for a ten-month common period was considered for GPM Era analysis. To study how well the satellite estimates with their finest temporal and spatial resolution capture single rainfall event and to explore their engineering application potential, an existing model of SF watershed prepared in Infoworks Integrated Catchment Model (ICM) was considered for hydrological simulation. Infoworks ICM is developed and maintained by Wallingford Software in the UK and SF watershed model is owned by San Francisco Public Works (SFPW). The historical analysis of TMPA products suggested overestimation of rainfall in CLT region while underestimation in SF region. This underestimation was largely associated with missed-rainfall events and negative hit events in SF. This inconsistency in estimation was evident in GPM products as well. However, in the study of single rainfall events with higher magnitude of rainfall depth in SF, the total rainfall volume and runoff volume generated in the watershed were over-estimated. Hence, satellite estimates in general tends to miss rainfall events of lower magnitude and over-estimate rainfall events of higher magnitude. From statistical analysis of GPM Era data, it was evident that GPM has been able to correct this inconsistency to some extent where it minimized overestimation in CLT region and minimized negative error due to underestimation in SF. GPM products fairly captured the hydrograph shape of outflow in SF watershed in comparison to TMPA. From this study, it can be concluded that even though GPM precipitation estimates could not quiet completely replace ground rain gage measurements as of now, with the perpetual updating of algorithms to correct its associated error, it holds realistic engineering application potential in the near future.

Thesis (MTech (Construction Management))--Cape Peninsula University of Technology, 2017. / The South African construction industry is faced with challenges which contribute to unsuccessful project delivery. Cost underestimation have negative contribution to construction projects, the effects and causes of cost underestimation have not been adequately explored with the objective of providing mitigating mechanisms. This study is aimed at investigating factors which contribute to cost underestimation, the prevalence of cost underestimation in relation to causes and effects of cost underestimation, with the final objective to establish mechanisms for efficient mitigation of cost underestimation. The study review literatures relating to cost estimation, and additional data were collected in form of a structured questionnaire. The questions highlight the following areas; project planning, method and techniques, and tools as factors contributing to cost underestimation; scope changes and risk associated with specialized building works as prevalence of cost underestimation; planning stage, design and material changes risk due to unforeseen factors as causes of cost underestimation; loss of reputation, exposure to risk and financial loss as effects of cost underestimation; and design requirements, effective techniques and planning as cost underestimation mitigation mechanism. A total of one hundred and forty two (142) emails were sent via the survey website to the selected respondents and seventy four (74) responses were received. A quantitative approach was used and a convenient purposive sampling of respondents was used by handpicking the respondents from the available register of the South African Council for Quantity Surveying Professions (SACQSP) and the general building contractors registered with Construction Industry Development Board (CIBD), construction professionals working in quantity surveying practice and construction firms within and around Cape Town.

The objectives of this thesis are to develop an analytical method for economic risk quantification during feasibility analysis for large engineering projects and to computerize the method to explore its behavior, to validate it and to test its practicality for the measurement of uncertainty of decision variables such as project duration, cost, revenue, net present value and internal rate of return. Based on the probability of project success the method can be utilized to assist on strategic feasibility analysis issues such as contingency provision, "go-no go" decisions and adopting phased or fast track construction. The method is developed by applying a risk measurement framework to the project economic structure. The risk measurement framework is developed for any function Y = g(X), between a derived variable and its correlated primary variables. Using a variable transformation, it transforms the correlated primary variables and the function to the uncorrelated space. Then utilizing the truncated Taylor series expansion of the transformed function and the first four moments of the transformed uncorrelated variables it approximates the first four moments of the derived variable. Using these first four moments and the Pearson family of distributions the uncertainty of the derived variable is quantified as a cumulative distribution function. The first four moments for the primary variables are evaluated from the Pearson family of distributions using accurate, calibrated and coherent subjective percentile estimates elicited from experts. The correlations between the primary variables are elicited as positive definite correlation matrices. The project economic structure describes an engineering project in three hierarchical levels, namely, work package/revenue stream, project performance and project decision. Each of these levels can be described by Y = g(X), with the derived variables of the lower levels as the primary variables for the upper level. Therefore, the input as expert judgements is only at the work package/revenue stream level. Project duration is estimated by combining the generalized PNET algorithm to the project economic structure. This permits the evaluation of the multiple paths in the project network. Also, the limiting values of the PNET transitional correlation (0,1) permits the estimation of bounds on all of the derived variables. Project cost and revenue are evaluated in terms of current, total and discounted dollars, thereby emphasizing the economic effects of time, inflation and interest on net present value and internal rate of return. The internal rate of return is evaluated from a variation of Hillier's method. The analytical method is validated using Monte Carlo simulation. The validations show that the analytical method is a comprehensive and extremely economical alternative to Monte Carlo simulation for economic risk quantification of large engineering projects. In addition, they highlight the ability of the analytical method to go beyond the capabilities of simulation in the treatment of correlation, which are seen to be significant in the application problems. From these applications a technique to provide contingencies based on the probability of project success and to distribute the contingency to individual work packages is developed. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

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Concrete block single-story detached homes are popular residences in Florida, but construction materials and methods must undergo changes to combat rising prices and material shortages. Those systems with the greatest pressure of price or material shortage will change first. When current costs and methods are examine, it is found that two systems, roof and exterior walls, have the greatest need for changes in the immediate future; and one system, thermal insulation, needs an empirical study. The roof is of materials which are in short supply and rapidly increasing in cost. The study concludes that, with present cost trends, metal frame members for the roof or a reinforced concrete slab roof are feasible alternatives. The exterior walls have excessive labor costs, and the feasible alternative may be cast-on-site masonry tilt-up panel walls. Power prices, electrical and fuel, create a need to establish new guidelines for the extent of home thermal insulation. The heat gains and losses are examined to direct future studies of the home's thermal insulation problems. The concrete block home will continue to be viable if the necessary innovations are implemented to reduce cost rate of increase and to reduce operating and maintenance costs.