University of Maryland, Baltimore County
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Modelling and Estimation of Characteristics of the Rainfall Distribution
No full textRainfall varies in space and time in a highly irregular manner and is described naturally in terms of a stochastic process. A characteristic of rainfall statistics is that they depend strongly on the space-time scales over which rain data are averaged. A spectral model of precipitation has been developed based on a stochastic differential equation of fractional order, which allows concise description of the second moment statistics over any space-time averaging scale. The model is thus capable of providing a unified description of both radar and rain gauge data. We test the model with radar and gauge data collected contemporaneously at the NASA TRMM ground validation sites located near Melbourne, Florida. Understanding precipitation is an essential component of climate modeling. Part of the calibration process for the recently launched GPM satellite involves comparison with radar observations. Ensuring that the radars are well calibrated is an import part of this process. We have used the developed stochastic model to explore sampling error for gauge and radar derived estimates of rain rates. This allows us to detect the presence and estimate the magnitude of any retrieval errors for the radar or gauge. We also formulated a standard linear regression analysis approach to the intercomparison of radar and gauge rain rate estimates in terms of the appropriate observed and model-derived quantities
A Semantic and Collaborative Approach to Community Health-Care
No full textCommunity Health Workers (CHWs) are an integral part of health-care in underserved or un-served areas. They act as liaisons between health-care providers and patients in communities. They collect information about illnesses, provide preventive and curative care and, report emergency cases to health center. However, the lack of information sharing and training support impedes the effectiveness of CHWs and their ability to correctly refer patients. We propose and describe a system for mobile and wearable computing devices called Remedy which assists CHWs in decision making and facilitates collaboration among them. Remedy can infer possible diseases and treatments by representing the diseases, their symptoms, and patient context in OWL ontologies and by reasoning over this model. The use of semantic representation of data makes it easier to share knowledge such as disease, symptom, diagnosis guidelines, and demography related information, between various personnel involved in health-care (e.g., CHWs, patients, health-care providers). We describe the Remedy system with the help of a motivating community health-care scenario and present an Android prototype for smart phones and Google Glass
Self-rated health and chronic disease status: A biopsychosocial examination
No full textPoor self-rated health is consistently associated with increased mortality risk. Here we examined whether self-rated health was similarly related to prevalent chronic disease. We further evaluated potential biopsychosocial mediators of the association including biomedical (i.e. white blood cell, hemoglobin, total cholesterol, albumin, resting systolic blood pressure, estimated glomerular filtration rate, body mass index), psychological (i.e. anxiety, depressive symptoms, perceived stress), and social (i.e. healthcare barriers, and poverty status) factors. Race was explored as a moderator. Participants were 2,802 adults (56% female; mean age = 48 years; mean education = 12 years; 58% Black) from the Healthy Aging in Neighborhoods of Diversity Across the Lifespan study (HANDLS). Self-rated health was dichotomized into Good and Poor categories, and the number of chronic diseases (diagnosed via history, laboratory testing, and physical examination) were summed. Likelihood of chronic disease as a function of self-rated health and its interaction with race was examined in sex-stratified negative binomial regressions, adjusted for relevant demographic factors and health behaviors. Results showed that, irrespective of race, poor self-rated health was associated with increased likelihood for chronic disease in men [OR = 1.26, 95% CI 1.070, 1.482] and women [OR = 1.32, 95% CI 1.157, 1.512]. Psychological factors attenuated this association for men (7%) and women (9%). Overall, the findings suggest that individuals may be largely accurate in evaluating their physical health status. However, further exploration of intermediary factors is warranted. Better understanding of how self-rated health impacts chronic disease may help clinicians identify individuals at greatest risk for mortality
A Novel Approach To Advanced Pedometry Using Hierarchical Processing
No full textFalls are a major cause of injuries in adults above the age of sixty-ve. The economic aftermath of falls and their consequent hospitalization can be extensive. A plausible way of mitigating this problem is accurate prediction of future falls and taking proactive remedial action. Problems in gait is a reliable indicator of a future fall, however, existing systems focus on gait analysis in clinical settings and are not tuned towards continuous gait analysis. This research presents the design of a novel textile capacitive sensor array-based system built into clothing that can reliably capture advanced pedometric parameters that can be used to determine gait attributes. The nal design utilizes hierarchical signal processing architecture that breaks down the signal processing algorithm into a hierarchy of processing elements. The system is prototyped using textile capacitive plates built into an elastic-bandage and a custom FPGA-based system and show that our system can accurately detect gait attributes that have high correlation with falls, while consuming minimal energy
APPROXIMATE SEARCH OF MALWARE CODE ACROSS A FAMILY OF MALWARE
No full textIn the ever-growing security risk of the technological world malware plays an important role. To protect the sensitive data from the malicious software, malware analysts need the best of the tools to identify and eliminate the potential risk that the hostile software may cause to disrupt the computer systems. The idea behind this research is to extend the ability of the existing tool OllyDbg that will ease the process of detecting similar patterns of bugs from the existing known malware. We do this by writing custom plugins that are supported by OllyDbg. The plugin searches for hex code from the existing family of malwares based on the principle of Ngram text matching. The resemblance of these byte codes is the key to help the analyst from making judgments about the malware code that looks suspicious of infecting the system. With this implementation, OllyDbg can now look and process data outside its environment
Prevention and Detection of SQL Injection Attacks at the Database layer
No full textA lot of research has gone into eliminating SQL Injection attacks over the past decade and yet it is one of the most prevalent web based attacked harming commerce as well as privacy today. This is a clear indicator that we need to look deeper than just the network and application layer to consolidate security recommendations and practices into the core of any application - its data layer. The aim of this thesis is to demonstrate as well as theorize features that can be ap- plied to the DBMS layer of web applications so that the lowermost layer responsible for managing and maintaining data is in itself capable enough to withstand unauthorized and malicious accesses and modifications of the data it protects. While a lot has been done to prevent code injection on the network layer and applica- tion (front-end) layer, the DBMS layer is seldom looked at as another layer to implement injection detection and prevention practices. In this paper, we look into (a) How we can implement current DBMS features to build additional security layers against SQL injection; and (b) Suggest additional features that can be used to further strengthen the DMBS security layer against injection attacks
Human-Assisted Machine Vision for the Visually Impaired
No full textApproximately 285 million people in the world are estimated to be visually impaired. In the increasingly complex urban world, indoor and outdoor navigation has become a difficult task for the visually impaired individuals, especially those who use wheelchairs and walking canes. They have limited travel choices and rely mostly on the pedestrian environment. Sidewalks and pedestrian crossings are important for their daily travel. Despite of having the laws that govern proper standards for accessibility-compatible sidewalks, time accessibility of sidewalks gets damaged over a period of time. Due to accessibility issues on sidewalks, travelling independently becomes difficult for the visually impaired wheelchair and walking cane users and they seek support from navigation systems. Real time navigation systems for the visually impaired pedestrians, assist them by notifying about any dangers in their path and navigates them around the obstacles. Machine vision based navigation systems lack a priori contextual information which is necessary for detecting obstacles in real time. Also, use of sensors like RADAR and LIDAR for real time obstacle detection increases the power requirements. Thus, having a priori accessibility maps containing geospatial data of accessibility issue locations is helpful for notifying visually impaired individuals in real time mode. We present WheelNav - a system which uses human-assisted machine vision for developing accurate sidewalk accessibility maps for the navigation of visually impaired individuals. A group of users called Volunteers, crowdsource geotagged images and other relevant information of sidewalk accessibility issues they observe in their city through a smartphone application. Further, computer vision technique called Perspective Transformation is used for identifying the accurate positions of sidewalk accessibility issue objects in crowdsourced images for creating accessibility map. This process is assisted by human workers called Turkers who use Amazon Mechanical Turk and provide feedback about the estimates of real world dimensions of objects in crowdsourced images
THE HIGH-ORDER QUANTUM COHERENCE OF THERMAL LIGHT
No full textThermal light, such as sunlight, is usually considered classical light. In a macroscopic picture, classical theory successfully explained the first-order coherence phenomena of thermal light. The macroscopic theory, based on the statistical behavior of light intensity fluctuations, however, can only phenomenologically explain the second- or higher-order coherence phenomena of thermal light. This thesis introduces a microscopic quantum picture, based on the interferences of a large number of randomly distributed and randomly radiated subfields, wavepackets or photons, to the study of high-order coherence of thermal light. This thesis concludes that the second-order intensity fluctuation correlation is caused by nonlocal interference: a pair of wavepackets, which are randomly paired together, interferes with the pair itself at two distant space-time coordinates. This study has the following practical motivations: (1) to simulate N-qbits. Practical quantum computing requires quantum bits(qubits) of N-digit to represent all possible integers from 0 to 2N-1 simultaneously. A large number of independent particles can be prepared to represent a large set of N orthogonal |0> and |1> bits. In fact, based on our recent experiments of simulating the high-order correlation of entangled photons, thermal radiation is suggested as a promising source for quantum information processing. (2) to achieve sunlight ghost imaging. Ghost imaging has three attractive non-classical features: (a) the ghost camera can see targets that can never be seen by a classic camera; (2) it is turbulence-free; and (3) its spatial resolution is mainly determined by the angular diameter of the light source. For example, a sunlight ghost image of an object on earth may achieve a spatial resolution of 200 micrometer because the angular diameter of sun is 0.53 degree with respect to Earth. Although ghost imaging has been experimental demonstrated by using entangled photon pairs and pseudo-thermal light, we still have difficulties to make sunlight ghost image. From the picture of macroscopic local statistics of intensity fluctuations, we may never find the problem that causes sunlight ghost imaging so difficult comparing with that of pseudo-thermal light. To achieve the goals in both fundamental understanding of physics and practical engineering applications, this thesis aims at studying the high-order quantum coherence of thermal light. The first successful attempt of this study is to invent a novel measurement scheme — Positive-Negative Intensity Fluctation Correlation(PNFC) protocol, to measure the intensity fluctuation correlation(or photon number fluctuation correlation) of thermal light. This new photodetection measurement protocol distinguishes positive and negative intensity fluctuations(or photon number fluctuations) of two or more photodetectors within a sequence of short time windows, and then calculates the statistical correlation between these individual fluctuations. With the help of this invention, an anti-correlation of thermal light in a typical Hanbury Brown and Twiss(HBT) interferometry was discovered, which cannot be understood from the view point of traditional macroscopic classical theory. In the microscopic quantum coherence picture, the observation is successfully explained as a nonlocal two-photon interference phenomenon. We also successfully simulated the behavior of Bell-state with thermal light. By manipulating polarization, a thermal Bell-like state was built from two incoherent and orthogonally polarized thermal radiations. With intensity fluctuation correlation measurement, a sinusoidal function with 100% visibility, which suggests thermal light as a feasible source for preparing qubits. Besides the fundamental significance, PNFC protocol also brings incredibly high contrast for quantum imaging, such as 100% visibility for ghost imaging. Above all, we invented a 100% Intensity Fluctuation Correlation of Chaotic-thermal Light and Turbulence-free Imaging System, which provides high contrast as well as high resolution. Based on the experiments of the simulations of quantum interference in thermal light and the dramatically improvement of the contrast in quantum imaging, this study of the high-order coherence of thermal light has a great significance both for fundamental physics and applications
An evaluation of the impact of obesity related legislation
No full textIn attempt to address the adult obesity epidemic in the U.S., several state legislatures have enacted laws to curtail rates of adult obesity (Stein & Colditz, 2004). Recent enacted policies include: menu labeling laws, snack taxes, and Complete Streets policy (Robert Wood Johnson, 2009). The aim of this dissertation was to evaluate the effectiveness of existing legislative efforts to limit rates of growth of adult obesity. I examined if anti-obesity legislation effectively reduces rates of adult obesity and if anti-obesity policies differ in their ability to diminish adult obesity. Several panel data sets were constructed using reported data for each state and the District of Columbia from 1995 to 2011 via the Behavioral Risk Factor Surveillance System (BRFSS), U.S. Department of Commerce, Bureau of Economic Analysis and the U.S. Census Bureau. Time series regression analysis was completed to assess the impact of these three policies at a state, group and individual level. At the state level, all three policies are associated with a decrease in adult obesity rates although, the magnitude is small and statistical significance varies by empirical model. At the individual level, all three policies are associated with a decrease in BMI, however, the magnitude is small and the only policy with statistical significance is menu labeling. At the group level, the policies vary in their effect on BMI by race, age, income, education and gender. Only menu labeling and snack tax policy are statistically significant at the group level. Although the magnitude of effect seen with these policies is small, any sign of a reversal in the growing obesity trend, a trend that has been unaltered for the past decade, could be seen as a sign of improvement from a public health perspective. The results of this study highlight how a one size fits all approach will not be effective in combating the obesity epidemic, rather an assortment of legislative policies are necessary
Setting the Welfare Agenda: a qualitative analysis of the reauthorization of Temporary Assistance for Needy Families (TANF)
No full textThe 1996 passage of Temporary Assistance for Needy Families (TANF) was made possible by a unique confluence of factors including the work of organized political entrepreneurs, a bipartisan government, the negative construction of welfare recipients by elected officials, the public, and the media, and a booming economy. However, since the inception of TANF, the economic and political context has changed, likely affecting the agenda-setting stage for reauthorization of the legislation. The debates about and actions regarding TANF reauthorization and/or the role of cash-assistance welfare in general occurs within the changing economic and political context at any given time. Using John Kingdon's multiple-streams agenda-setting theory, this study examined welfare discourse to analyze how the policy community viewed the role of TANF within the deep recession in the first decade of the twenty-first century and which specific factors have influenced the tone and direction of its reauthorization. The study also integrated review of social construction and the economy into the multiple-stream agenda-setting framework in order to explore how these two factors were related to the agenda-setting process in the post-2010 reauthorization discourse. The research data was collected through the conduct and coding of informant interviews and the review of a sampling of Congressional hearings. I conducted 14 stakeholder interviews between September 2012 and November 2012: 8 participants were from inside the government (the Administration, Civil Servants, and Congress) and 6 participants were from outside the government (interest groups, media, academic/researchers/consultants, social movement). I cross-compared a sample of reauthorization-related committee hearings from 2001-2006 (the 107th-109th Congresses) with a sample of reauthorization hearings from 2007-2011 (the 110th - 112th Congresses). To provide a larger context, I analyzed relevant scholarly articles and public opinion polls and included ethnographic information gathered from interview field-notes. The three research objectives included: (1) to determine if the social construction of TANF recipients was related to the placement of TANF reauthorization on the governmental agenda; (2) to determine if the state of the economy was related to the placement of TANF reauthorization on the governmental agenda; and (3) to determine what factors (in addition to, or instead of) were related to the placement of TANF reauthorization on the political agenda. Results from this study indicate that the TANF reauthorization effort in this time period was far removed from an open policy window. There was no identified problem: extensions continued to maintain funding, cases were not increasing, and the public was not demanding action. Additionally, past entrepreneurs became fragmented or concerned with different topics, the implementation of the policy became standardized and incorporated into administrative practice, and the policymakers were wary about expending their political capital on a still divisive topic. Regarding research objective one, results show that the negative social construction of the welfare program, if not the welfare recipients themselves, remained a barrier to reauthorization. While the participants in the interviews expressed a sympathetic tone when describing TANF recipients, they asserted that those accepting cash-based assistance continued to be negatively constructed by both the public and politicians. For research objective two, results show that another barrier to reauthorization in this period was the depressed economy. Despite the state of the economy and increased unemployment there was not considerable support for increasing TANF spending in the recession, in part due to the negative social construction still attributed to this target population and competition among social programs. Finally, while the research was designed to specifically pull out themes associated with the social construction of TANF recipients and the state of the economy, an exploratory research objective was utilized to examine what other factors contribute to why the TANF program had not been reauthorized. As a result of this analysis, 4 themes that influenced the likelihood of change were identified: 1) the existing TANF policy was popular; 2) the welfare community (of states, administrators, and advocates) feared that any changes made might be punitive; 3) there were no identified active entrepreneurs; and 4) the topic of welfare was too politically divisive. The study intended to further inform the field of welfare agenda-setting practices by exploring the effects of multiple factors, including an economic recession, on the agenda-setting stage of welfare. Additionally, the study added to the theoretical understanding of the social construction of public assistance policy