Because the operational characteristics of signalized intersections near highway-railroad grade crossings (IHRGCs) are different from those of signalized intersections located elsewhere in the traffic system, standard operational strategies do not apply. This is because safe operation at IHRGCs takes precedence over all other objectives. Because the prime objective of the current preemption methods is to clear the crossing, secondary objectives such as safe pedestrian crossing time and minimized delay are given less consideration or ignored completely. Consequently, state-of-the-practice strategies may cause serious pedestrian safety and efficiency problems at IHRGCs. Therefore, there is a definite need for research on how to improve traffic signal preemption strategies. An important element of preemption strategy is detection of trains and prediction of arrival times. However, because of the limitations of current detection technologies, estimation algorithms, etc., there is a wide range in these warning times. In this dissertation, a new train-arrival prediction algorithm was developed using detection equipment located farther upstream from the HRGC. The state-of-the-art transition preemption strategy (TPS) was developed to ensure that as preemption is initiated by approaching trains, the signal display does not change in a manner that endangers either pedestrians or drivers. However, because it does not account for the variability of predicted train arrival times, there is still a possibility of failure. Therefore, a new transition preemption algorithm that is specifically designed to improve intersection performance while maintaining or improving the current level of safety is developed. This dissertation developed a preemption strategy (TPS3) that uses better train arrival time estimates to improve the safety and efficiency of IHRGCs. The approach was simulated on a test bed in College Station, Texas, and it was concluded that the new TPS improves the safety and operation of intersections near highway-railroad grade crossings.

Excessive coupling between object-oriented classes in systems is generally acknowledged as harmful and is recognised as a maintenance problem that can result in a higher propensity for faults in systems and a „stored up‟ future problem. Characterisation and understanding coupling at different levels of abstraction is therefore important for both the project manager and developer both of whom have a vested interest in software quality. In this Thesis, coupling trends are empirically investigated over multiple versions of seven Java open-source systems (OSS). The first investigation explores the trends in longitudinal changes to open-source systems given by six coupling metrics. Coupling trends are then explored from the perspective of: the relationship between removed classes and their coupling with other classes in the same package; the relationships between coupling and 'warnings’ in packages and the time interval between versions in Java OSS; the relationship between some of these coupling metrics are also explored. Finally, the existence of an 80/20 rule for the coupling metrics is inspected. Results suggest that developer activity comprises a set of high and low periods (peak and trough‟ effect) evident as a system evolves. Findings also demonstrate that addition of coupling may have beneficial effects on a system, particularly if they are added as new functionality through the package Java feature. The fan-in and fan-out coupling metrics reveal particular features and exhibited a wide range of traits in the classes depending on their high or low values; finally, we revealed that one metric (fan-in) is the only metric that appears consistently to exhibit an 80/20 (Pareto) relationship.

Over one million high school students drop out of school each year in this country. Dropping out of school is a serious problem for the student, community, and the nation. Often dropouts are unable to compete in an increasingly technological society and face numerous consequences from their decision to leave school early including higher levels of poverty, unemployment, public assistance, incarceration, and poor health. Dropping out is a gradual process of school disengagement and related to individual, family, and school factors. In the past, it has been difficult to track individual student's progress through school and to determine accurate dropout and graduation rates. In 2005, the National Governors Association made a commitment to implement a uniform method to calculate and report graduates and dropouts as well as better data collections systems.This study intended to replicate aspects of other major studies around the county to determine the best early predictors of dropping out of school in this large school district in southern Arizona and use this information to build an early warning system. Student data were obtained from the district's Research and Accountability office for a cohort of students (n=6751) who began the ninth grade in fall 2006 and graduated or should have graduated in 2010. Data collected included general demographic information, academic data, number of schools attended, and school withdrawal codes.The intent of this research was to determine if there were statistically significant differences between dropouts and graduates in the variables collected and which variables yielded the highest effect sizes and should be included in the district's early warning system.Two analyses were used to determine significance differences between dropouts and graduates. Then four analyses were performed to determine the highest-yield variables for this district. Consistent with recent research in the field, the variables of ninth grade attendance, ninth grade English and Math grades, and GPA were the strongest predictors of student dropouts.Local educators can use this early warning information to help identify potential high school dropouts as early as possible and intervene more efficiently and effectively with these students.

The aim of this study is to propose an alternative approach in prognostics for airborne avionics system in order to enhance maintenance process and aircraft availability. The objectives are to analyse the dependency of avionic systems for fault propagation behaviour degradation, research and develop methods to predict the remaining useful life of avionics Line Replaceable Units (LRU), research and develop methods to evaluate and predict the degradation performances of avionic systems, and lastly to develop software simulation systems to evaluate methods developed. One of the many stakeholders in the aircraft lifecycle includes the Maintenance, Repair and Overhaul (MRO) industry. The predictable logistics process to some degree as an outcome of IVHM gives benefit to the MRO industry. In this thesis, a new integrated numerical methodology called ‘System Level Airborne Avionic Prognostics’ or SLAAP is developed; looking at a top level solution in prognostics. Overall, this research consists of two main elements. One is to thoroughly understand and analyse data that could be utilised. Secondly, is to apply the developed methodology using the enhanced prognostic methodology. Readily available fault tree data is used to analyse the dependencies of each component within the LRUs, and performance were simulated using the linear Markov Model to estimate the time to failure. A hybrid approach prognostics model is then integrated with the prognostics measures that include environmental factors that contribute to the failure of a system, such as temperature. This research attempts to use data that is closest to the data available in the maintenance repair and overhaul industry. Based on a case study on Enhanced Ground Proximity Warning System (EGPWS), the prognostics methodology developed showed a sufficiently close approximation to the Mean Time Before Failure (MTBF) data supplied by the Original Equipment Manufacturer (OEM). This validation gives confidence that the proposed methodology will achieve its objectives and it should be further developed for use in the systems design process.

‘Tipping points’ in the climate system are characterised by a nonlinear response to gradual forcing, and may have severe and wide-ranging impacts. One of the best ways to identify and potentially predict threshold behaviour in the climate system is through analysis of palaeoclimate records. It has been suggested that early warning signals occur on the approach to a tipping point, generated from characteristic fluctuations in a time series as a system loses stability. Although early warning signals have been found in climate models and high-resolution marine and ice core palaeodata, studies from terrestrial records are lacking. In this study, a number of Pleistocene terrestrial records were selected to represent a range of regions strongly influenced by different climate modes which are thought to be capable of displaying threshold behaviour. These records included lake sediments from the North Atlantic, tree-rings from the South Pacific, a Chinese speleothem and were complemented by a new Greenland ice core chronology. Recently developed methods to detect signals of ‘critical slowing down’, ‘flickering’, and stability changes on the approach to a tipping point were utilised. Specific methodological issues arising from analysing palaeoclimate data were also investigated using a simple bifurcation model. A number of key criteria were found to be necessary for the reliable identification of early warning signals in palaeoclimate records, most crucially, the need for a low-noise record of sufficient data length, resolution and accuracy. Analysis of a Chinese speleothem identified the East Asian Summer Monsoon as an important climate ‘tipping element’, which may display a cascade of impacts. However, in some cases where early warning signals may fail, a deeper understanding of the underlying system dynamics is required to inform the development of more robust system-specific indicators. This was exemplified by the analysis of an abrupt, centennial-duration shutdown recorded during the Younger Dryas Chronozone in New Zealand, which demonstrated no slowing down, consistent with a freshwater pulse into the Southern Ocean. This study demonstrates that time series precursors from palaeoclimate archives provide a means of useful forewarning of many potential climate tipping points.

Many species use visual features to avoid predation by several methods, such as concealing themselves, deceiving predators and hindering capture. One of the most striking strategies is aposematism, or warning coloration, in which prey use conspicuous visual signals to advertise chemical or physical defences, and thereby deter predators from attacking. My thesis focuses on the form of these warning signals, namely which elements of visual patterns might be most effective in generating predator avoidance, as well as how these different visual features relate to defence levels and ultimately to prey survival in the wild. To address these issues, I studied the warning signals of Lepidoptera and in particular burnet moths (Zygaenidae: Zygaeninae), day-flying moths with distinctive red and black wings and the remarkable ability to both synthesise defensive compounds and sequester them from their host plants. Technological advances and a growing understanding of animal vision mean that animal signals can be studied in an increasingly precise and ecologically-relevant way. Throughout this thesis, I use sophisticated methods to quantify both the defensive chemicals and wing coloration of burnet moths, as perceived by their avian predators. I examine the key features of day-flying defended Lepidoptera, then focus on the potential for quantitative signal honesty in burnet moths. I explore the relationship between defence levels and measures of coloration, both within the six-spot burnet moth, Zygaena filipendulae, and across species in the Zygaenidae, then test the effects of variation in warning signals on predation risk for artificial burnet-like prey in the field. My work highlights some of the complicating factors that should be accounted for in the study of warning coloration, especially when investigating the potential for quantitative signal honesty. I hope my thesis will provide a basis for future research on the defensive strategies of day-flying moths and inspire others to pursue investigations into aposematism in the Zygaenidae.

Collision warning systems represent a promising means to reduce rear-end crash involvement. However, these systems experience failures in the real-world that may promote driver distrust and diminish drivers' willingness to comply with warnings. Recent research suggests that not all false alarms (FAs) are detrimental to drivers. However, very few studies have examined how different alarms influence different driving populations. The purpose of this research was to examine how younger, middle-aged, and older drivers (with and without UFOV impairments) evaluated and responded to four different alarm contexts - false alarm (FA), nuisance alarm (NA), unnecessary alarm (UA) and true alarm (TA) - when they did and did not receive warnings. FA contexts represent out-of-path conflict scenarios where it is difficult for the driver to identify the source of the alarm. NA contexts represent out-of-path conflict scenarios that occur in a predictable manner that allows drivers to identify the source of the alarm. UA contexts are transitioning host conflict scenarios where the system issues an alert but the situation resolves itself before the driver needs to intervene. TA contexts represent in-host conflict scenarios where the situation requires the driver to intervene to avoid a collision. The results suggest that alarm context does matter. Compared to response data that differentiates FA and NA from UA and TA, subjective data shows greater sensitivity and differentiates between all four alarm contexts (FA Younger drivers indicated a high degree of confidence in their own ability across the different conditions. While they adopted a similar response pattern as middle-aged drivers during the TA contexts, these drivers responded less frequently than middle-aged and older drivers during the UA context. Diminished hazard perception ability and the tendency to consider these situations less hazardous likely account for the fewer responses made during these situations by younger drivers. Older drivers with and without UFOV impairments indicated similar hazard ratings for UA and TA contexts, yet drivers with UFOV impairments responded less frequently in both alarm contexts. Diminished hazard perception ability, slower simple response times, and degraded contrast sensitivity likely account for the fewer and slower responses. Interestingly older drivers with impairments did respond more frequently when warned during the TA context. They also rated FAs and NAs more positively than the other driver groups. The results of this study suggest applying signal detection theory without concern for the alarm context and driver characteristics is insufficient for understanding how different alarms influence operators and that subjective data can inform design. Researchers are encouraged to combine multiple perspectives that incorporate of both an engineering and human perspective.

<p>This paper presents a method for recognition of flame types coming from different kinds of fuel through analysis of flame images. Accurate detection of fire alarm and achievement of early warning is positive development for cities fire safety. Image-based fire flame detection technology is a new effective way to achieve early warning through the early fire flame detection. Different fuel combustion in air it the basic of basis to recognize the type of flame. The application built up by using generic color model and the techniques of image analysis.</p>

A significant number of aircraft incidents and accidents have been caused, in part, by flightcrew failure to properly manage cockpit activities, such as failure to initiate activities at the appropriate time, misprioritization of activities, or the failure to appropriately monitor activities and terminate them when required. To facilitate the management of the cockpit activities, a computational aid, the Agenda Manager (AM) has been developed for use in simulated cockpit environments in an investigation which was one aspect of a more extensive research project supported by the NASA Ames Research Center. The AM is directed at the management of goals and functions, the actors who perform those functions, and the resources used by these actors. Development of an earlier AM version, the Cockpit Task Management System (CTMS), demonstrated that it could be used to assist flightcrews in the improvement of cockpit activity management under experimental conditions, assuming that the AM determined pilot goals accurately as well as the functions performed to achieve those goals. To overcome AM limitations based on that assumption, a pilot goal communication method (GCM) was developed to facilitate accurate recognition of pilot goals. Embedded within AM, the GCM was used to recognize pilot goals and to declare them to the AM. Two approaches to the recognition of pilots goals were considered: (1) The use of an Automatic Speech Recognition (ASR) system to recognize overtly or explicitly declared pilot goals, and (2) inference of covertly or implicitly declared pilot goals via use of an intent inferencing mechanism. These two methods were integrated into the AM to provide a rich environment for the study of human-machine interactions in the supervisory control of complex dynamic systems. Through simulated flight environment experimentation, the proposed GCM has demonstrated its capability to accurately recognize pilot goals and to handle incorrectly declared goals, and was validated in terms of subjective workload and pilot flight control performance. / Graduation date: 1997

This dissertation contends that interpreters have underestimated assurance of salvation in the Letter to the Hebrews and the author's confidence in his recipients' salvation. Chapter 1 considers the history of research, examining how several recent commentators and interpreters have understood the warnings and assurance in the letter. Special attention is given to their interpretation of the perfection of believers and the new covenant promises, as well as the author's confidence, God's promise, and the believer's hope in Hebrews 6:9-20. Chapter 2 examines the concept of perfection in Hebrews--with respect to Christ and believers--and specifically considers its relationship to the promises of the new covenant as prophesied in Jeremiah 31, quoted in Hebrews 8:8-12 and 10:16-17. I analyze several relevant texts, including 3:7-4:13; 7:11-28; 8:1-13; 9:1-10; 10:1-18, 22; 11:39-40; 12:18-24; and 13:20-21, and consider implications for assurance of salvation. Chapter 3 provides an exegetical analysis of Hebrews 6:9-20, seeking to understand the author's confidence in the recipients and the contribution the passage makes to assurance of salvation in Hebrews. Chapter 4 offers an explanation of the warnings of Hebrews that can account for the findings of chapters 2 and 3. I consider and evaluate the three most common interpretations of the warnings: the loss-of-rewards view, the false-believer view, and the loss-of-salvation view. Building on this, I present the "means-of-salvation" view, responding to criticisms of the view and demonstrating how it best integrates the warnings with the passages and themes that promote Christian assurance. Thus, I defend the thesis that interpreters of Hebrews have greatly underestimated assurance of salvation in the letter (1) by demonstrating that the author implicitly affirms his readers can have assurance of salvation in light of the sacrificial work of Christ and (2) by demonstrating that the means-of-salvation view offers the best means of integrating assurance of salvation with the warnings against Christian apostasy in the letter.