Browsing by Subject "analysis"
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Item An analysis of selected decision making variables and the effects they have on the post-secondary education plans of 16-21 year old youth from the United States(Texas A&M University, 2007-09-17) Takao, Marsha Jane McCordThe primary purpose of this study was to determine the importance of postsecondary education in the future plans of 16-21 year old youth from the United States. A secondary purpose of the study was to determine if selected individuals in their lives influence the post-secondary education decisions made by 16-21 year old youth in the United States. In addition, selected outcome options were analyzed to determine the effect these options have on post-secondary education decisions made by 16-21 year old youth from the United States. The sample for the study consisted of 3,017 males and females between the ages of 16-21, collected by means of a telephone survey. The dependent variable for this study was the higher education plans of 16-21 year old youth; and the independent variables were age, gender, ethnicity, usual grades made in high school, strength of influence of selected outcome options, and influencers of the decisions made by the respondents. The study found that 16-21 year old youth in the United States have a strong desire to attend post-secondary education full-time rather than part-time. A majority of the respondents indicated that they prefer attending a 4-year college or university with the second choice being a 2-year junior or community college. The respondents indicated that they are influenced strongly by their parents, siblings, and close friends to make decisions; but there does not appear to be a strong influence by this group on the respondents to make decisions about post-secondary education. The outcome options that appear to have the most influence on this age group are: having a job that makes you happy, having a good paying job, earning money for college, having an attractive lifestyle, preparing for a career, having job security, making a positive difference in the community and learning a valuable trade or skill. These factors, however, don??????t appear to have a strong influence on this group when making a decision to attend post-secondary education.Item An Analysis of the Impact of Reducing Pedestrian-Walking-Speed on Intersection Traffic MOEs(2015-01-26) Li, XiaohanPedestrian traffic is an important element in signalized intersection analysis. As a low-speed traffic component, pedestrians crossing the street may take up time that could be utilized by vehicles on the other street to pass through the intersection, and this causes an increase in the total delay at the intersection. Therefore, to minimize traffic delays and increase traffic efficiency, it is important to study the impact of pedestrian walking speed. This study was conducted to analyze the impacts of pedestrian speed under different lane group combinations, median widths, volumes on major and minor streets, and pedestrian pushbutton horizontal offsets. The idea originated came from the reduction of pedestrian walking speed used for calculating the pedestrian intervals. The 2003 MUTCD specified a value of 3.5 ft/sec to calculate the pedestrian clearance time and this speed was reduced to 4.0 ft/sec in the 2009 MUTCD. Moreover, a second method using 3.0 ft/sec to calculate the total pedestrian intervals was added to the 2009 MUTCD. This change is likely to influence the signal timing plan of entire intersections and further increasing the intersection total delay. The researcher used one of the most popular simulation software programs, Synchro 7, to simulate various types of intersections under different traffic circumstances and yield a series of datasets to analyze the impacts of the reduction in pedestrian walking speed. The data was analyzed both horizontally and vertically. By comparing the intersection total delay as well as the through lane group and the approach average delay, the researcher analyzed their differences mathematically as well as practically. According to the analysis results, if the cycle length of an intersection can be optimized, the change of pedestrian walking speed would not make significant impact on intersection delay; however, if under a given cycle length other than its optimum one, the intersection delay would increase significantly after the change of pedestrian walking speed in some circumstance. The extended pushbutton press function can be used to alleviate such delay increase.Item Analysis of WACSIS data using a directional hybrid wave model(Texas A&M University, 2007-04-25) Zhang, ShaosongThis study focuses on the analysis of measured directional seas using a nonlinear model, named Directional Hybrid Wave Model (DHWM). The model has the capability of decomposing the directional wave field into its free wave components with different frequency, amplitude, direction and initial phase based on three or more time series of measured wave properties. With the information of free waves, the DHWM can predict wave properties accurately up to the second order in wave steepness. In this study, the DHWM is applied to the analyses of the data of Wave Crest Sensor Inter-comparison Study (WACSIS). The consistency between the measurements collected by different sensors in the WACSIS project was examined to ensure the data quality. The wave characteristics at the locations of selected sensors were predicted in time domain and were compared with those recorded at the same location. The degree of agreement between the predictions and the related measurements is an indicator of the consistency among different sensors. To analyze the directional seas in the presence of strong current, the original DHWM was extended to consider the Doppler effects of steady and uniform currents on the directional wave field. The advantage of extended DHWM originates from the use of the intrinsic frequency instead of the apparent frequency to determine the corresponding wavenumber and transfer functions relating wave pressure and velocities to elevation. Furthermore, a new approach is proposed to render the accurate and consistent estimates of the energy spreading parameter and mean wave direction of directional seas based on a cosine-2s model. In this approach, a Maximum Likelihood Method (MLM) is employed. Because it is more tolerant of errors in the estimated cross spectrum than a Directional Fourier Transfer (DFT) used in the conventional approach, the proposed approach is able to estimate the directional spreading parameters more accurately and consistently, which is confirmed by applying the proposed and conventional approach, respectively, to the time series generated by numerical simulation and recorded during the WACSIS project.Item Making the business case for process safety using value-at-risk concepts(Texas A&M University, 2006-10-30) Fang, Jayming ShaAn increasing emphasis on chemical process safety over the last two decades has led to the development and application of powerful risk assessment tools. Hazard analysis and risk evaluation techniques have developed to the point where quantitatively meaningful risks can be calculated for processes and plants. However, the results are typically presented in semi-quantitative ??????ranked list?????? or ??????categorical matrix?????? formats, which are certainly useful but not optimal for making business decisions. A relatively new technique for performing valuation under uncertainty, Value at Risk (VaR), has been developed in the financial world. VaR is a method of evaluating the probability of a gain or loss by a complex venture, by examining the stochastic behavior of its components. We believe that combining quantitative risk assessment techniques with VaR concepts will bridge the gap between engineers and scientists who determine process risk and business leaders and policy makers who evaluate, manage, or regulate risk. We present a few basic examples of the application of VaR to hazard analysis in the chemical process industry. We discover that by using the VaR tool we are able to present data that allows management to make better informed decisions.Item Mathematical modelling and analysis of calcium oscillations in excitable and non-excitable cell lines(Texas A&M University, 2004-09-30) Hegde, Bharati KrishnaInformation is transmitted from the cell surface to various specific targets in the cell via several cellular signaling pathways. Cytosolic free calcium (Ca2+)is one of the most versatile and ubiquitous intracellular messengers since it is able to regulate diverse number of functions such as proliferation, secretion, fertilization, metabolism, learning and memory. In the last couple of years, evidence has been accumulating that Ca2+ ion is able to integrate information from multiple signaling pathways and convert this information into a code which regulates events ranging from contraction to modification of gene expression (Berridge et al. 1998). It was shown that Ca2+ concentration displays oscillatory behavior in response to agonist stimulation in a variety of cells(Goldbeter 1996) and the frequency of these oscillations increases with the concentration of agonist, a behavior called frequency encoding which has led to the concept that many Ca2+-regulated processes are controlled by these codes(Berridge 1998). Although the presence of Ca2+ oscillations and the sources of Ca2+ pools involved is known in many cell types, it is yet not known how the various frequencies of Ca2+ oscillations are converted into codes that regulate the numerous cellular events. Recently a number of cellular targets that decode Ca2+ signals and are tuned to the frequency of Ca2+ oscillations have been identified. Prominent among them are calcium-calmodulin kinase II (CAM II) and protein kinase C (PKC). The objective of this work is to study and mathematically model the oxytocin and vasopressin-induced Ca2+ oscillations in cells of normal rat liver (Clone 9) and cells of pregnant human myometrium. The proposed model accounts for the receptor-controlled Ca2+ oscillations involving positive feedback leading to activation of phospholipase C (PLC) and negative feedback from PKC onto G-proteins which simulates many of the features of observed intracellular Ca2+. The model also incorporates the concept that coordinated Ca2+ signals in a group of hepatocytes require both effective gap junctions and the presence of agonist at each cell surface. Another objective of this research is to understand the relevance of frequency-encoded signals by performing an analysis of frequencies of Ca2+ oscillations using the Fast Fourier Transform and the Wavelet Transform. The validity of the model was confirmed by using statistical tests to check if the frequencies and amplitudes of the experimental Ca2+ oscillations match with those of the modelled oscillations.Item The Conservation and Analysis of Small Artifacts from the Site of USS Westfield(2013-05-30) Stika, Jessica RoseIn the early hours of 1 January 1863, USS Westfield grounded hard in the sand off the northeast side of Pelican Spit in Galveston Bay, Texas. The gunboat was building up steam to cut off two Confederate cottonclads before they reached the other Union ships in the bay. Hours later, an explosion ripped through the hull, sinking the vessel in the shallow water. Scuttled by the captain, William B. Renshaw, Westfield lay in the sands of Galveston Bay until the remains were excavated in 2009 and 2010 by PBS&J, now Atkins Global, under the supervision of the Texas Historical Commission and the U.S. Navy. The artifacts were brought to the Conservation Research Laboratory on Texas A&M University?s Riverside Campus where they were sorted, documented, and conserved. This thesis begins with a detailed account of Westfield?s history, starting with the vessel?s use as a New York ferryboat, the conversion to a gunboat and commission in the West Gulf Blockading Squadron, and, finally, the explosion and sinking during the Second Battle of Galveston and subsequent Confederate salvage attempts. Following this is a summary of the conservation methods used for Westfield artifacts, including an experiment on the treatment of waterlogged cast iron from the ship. A catalog of the artifacts, providing research on the various types of materials in the collection and a short summary of the artifact types, is also presented.Item The Renewable Fuel Standard and Ethanol Pricing: A Sensitivity Analysis(2014-04-18) McNair, RobertVolatile oil prices and political uncertainty surrounding uninterrupted oil supplies has pressured the U.S. Congress and economists to search for substitutes. In response, the U.S. has enacted policies to directly support the production and use of biofuel. The current Renewable Fuel Standard (RFS) requires 36 billion gallons of renewable fuel use by 2022. A large proportion of the mandate is to consist of corn-based ethanol. Most ethanol is consumed in the U.S. as a 10 percent blend of ethanol and gasoline. In 2014, it is projected oil refineries will hit the blend wall (BW). In short, oil refineries are required to blend more ethanol into gasoline than is allowed by the Environmental Protection Agency (EPA). As a consequence, the EPA will need to either reduce the Renewable Fuel Standard for 2014, or permit additional ethanol blends to be sold. Overall, the purpose of the study was to analyze the economic impact of changing energy policy on ethanol markets. A structural, supply and demand model was developed. Four equations were estimated, and residuals were simulated to estimate probability distributions for monthly ethanol prices and total demand. Alternative scenarios were developed to estimate how the RFS, the BW, and corn prices affect ethanol markets. The parameter estimates indicated the major determinants of ethanol demand were the RFS and the BW. The results showed the RFS and the BW positively affected the price of ethanol and demand. The base scenario estimated average ethanol price to be $1.89/gal. When the RFS was reduced by 10.59 percent, ethanol prices were estimated to decline $0.29/gal, compared to the base scenario. Total demand declined 600 million gallons. If the BW was increased to 15 percent, the price of ethanol increased approximately $1.10/gal from the base scenario. Total demand increased 1.4 billion gallons in response. Ethanol prices were found to be insensitive to corn prices.