University of Maryland, Baltimore County
Not a member yet
17643 research outputs found
Sort by
Polarized Imaging Nephelometer Development and Applications on Aircraft
No full textSatellite remote sensing is the only method that is able to measure climate forcing atmospheric constituents on a global scale. Aerosols have large impacts on climate, through influencing radiation directly and through their effects on clouds. Remote sensing algorithms that deduce aerosol properties from satellite measurements of scattered sunlight rely on information about scattering patterns of aerosols. Chapter 1 places the work in context through a literature survey, and introduces and clarifies theoretical constructs necessary for understanding the remaining chapters. In order to improve our understanding of light scattering by aerosol particles, and to enable routine in situ airborne measurements of aerosol light scattering to calibrate and validate satellite algorithms, at LACO (Laboratory for Aerosols Clouds and Optics) we have developed an instrument called the Polarized Imaging Nephelometer (PI-Neph). We designed and built the portable PI-Neph instrument at UMBC (University of Maryland, Baltimore County); it directly measures the ambient volume scattering coefficient and the phase matrix elements P11, phase function, and -P12/P11, polarized phase function. Chapter 2 introduces the PI-Neph instrument, while chapter 3 lays out the calibration and data reduction algorithm. The PI-Neph employs illuminating lasers and polarization control, sampling of ambient air through an inlet, and wide field of view detection of scattered light in a scattering angle range of 3? to 176?. The instrument does not employ any moving parts, therefore it is robust and fast enough for airborne measurements. The PI-Neph first measured at a laser wavelength of 532nm, and was first deployed successfully in 2011 aboard the B200 aircraft of NASA Langley during the DEVOTE (Development and Evaluation of satellite ValidatiOn Tools by Experiments) project. In 2013, we upgraded the PI-Neph to measure at 473nm, 532nm, and 671nm nearly simultaneously. LACO has deployed the PI-Neph on a number of airborne field campaigns aboard three different NASA aircraft. This dissertation describes the PI-Neph instrument, the measurement approach, algorithm, and calibrations. Chapter 4 is a validation and error analysis case study, which quantifies the exceptionally good agreement of artificial polystyrene sphere data with Mie theory. The PS sphere validation data was collected during the 2012 deployment for the Deep Convective Clouds and Chemistry (DC3) field campaign. Residuals between Mie fit and PS data (angular mean and population standard deviation) in case of the cross fits were the following. The differences of P11 data and P11 fit (predicted by fit to -P12/P11), relative to the P11 data, was -1.9% ? 5.5%. The differences of -P12/P11 data versus -P12/P11 fit (predicted by the fit to P11) was 0.028 ? 0.062. Chapter 4 also quantifies the P11 and -P12/P11 calibration errors through a Monte Carlo simulation. At an ambient aerosol scattering coefficient of 100 Mm-1, it is estimated that the PI-Neph will measure P11 (at individual scattering angles) with relative systematic error of approximately 2.3%, and -P12/P11 with absolute systematic error of approximately 0.033. Chapter 5 presents highlights from field measurements. The DEVOTE project enabled the initial PI-Neph results, such as scattering coefficient validation via comparison to other measurements, comparison of polystyrene sphere data to Mie theory, a comparison to AERONET derived phase function, and retrieval of microphysical properties of aerosols in collaboration with Dr. Oleg Dubovik. Chapter 5 also provides an overview of DC3 data, an assessment of data quality, and quantifications of PI-Neph capabilities and noise levels. This dissertation demonstrates the capability of the PI-Neph to measure ambient levels of aerosols down to 10 Mm-1, by measurement examples from the DEVOTE and DC3 aircraft deployments. As a conclusion, an itemized list of accomplishments is given in chapter 6, along with promising future research directions
Advances in microchannel heating and cooling based on fine scale heterogeneity of thermal conductivity; Theory, Optimization, and Experimental Validation
No full textA major advance in microchannel heating and cooling technology is described and has the potential to change the way thermal processing of microscale fluidic samples is achieved. The microchannel is one of the key building blocks of micro total analysis systems (?TAS), which are already being released to market in the form of disposable test kits for biometrics and disease identification. However, significant cost reductions and other advances in microchannel heating and cooling technology are still needed and can be expected to improve the accuracy with which quantitative analysis can be performed. In part, this is because the fidelity of many existing and potential microfluidic applications is critically dependent on precise temperature control. The scientific objective of the study was to understand and then manipulate the physics of thermal transport within fine scale composite materials containing an embedded microchannel. In essence, it was necessary that the composition of the composite materials be manipulated in a precise way that established a particular nonlinear pattern of temperature along the length of the microchannel. In practice, this required the development of a systematic inverse solution process that could identify an acceptable composition to exactly match the desired pattern of temperature variation. As a demonstration of capability, fully operational prototypes comprised of patterned copper laminated within polyimide and acrylic polymers were designed, fabricated, and tested. In terms of conceptual advances, this is the first time that composite materials of this type have been used for microchannel heating AND cooling. From an analytical perspective, the critical advance was the development of a robust simulation framework consisting of an outer optimization loop and an inner finite element analysis (FEA) loop, which was used to iteratively identify the optimal copper pattern for each of several applications. In terms of experimental advances, the key fabrication steps included UV laser micromachining, acid etching, microchannel formation, and hot vacuum lamination. To avoid any ambiguity or artifact, microchannel temperatures were painstakingly measured at each of several flow rates using fine thermocouples embedded in the microchannel wall. For the most part, the measured temperatures were within 1 ?C of the expected values based on simulation, with spatial temperature gradients of up to +/-94 ?C/mm (or equivalently +/-188 ?C/s at 2 l/min flow rate) within the range of 16 ?C to 92 ?C, using a resistively heated source at 100 ?C and a thermoelectrically cooled sink at 2 ?C. The temperature profiles studied here included two highly nonlinear cyclical profiles applicable to 1) continuous-flow polymerase chain reaction (PCR) and 2) thermally mediated counter-flow separation in conjunction with electrophoresis
CERTIFIED NURSE AIDE SCOPE OF PRACTICE: IMPACT ON QUALITY OF CARE, NURSING AIDE BELIEFS, AND CLINICAL PRACTICE.
No full textOlder adults utilize more health care services than various other populations due to the complex nature of their health care needs. As acuity in health conditions increase, experienced care providers such as Certified Nurse Aides (CNAs) will be needed to offer hands-on care including care for the treatment of complex conditions. CNAs are essential caregivers, providing care that directly impacts resident outcomes. CNAs are currently only trained to provide a basic level of care and are not permitted to handle complex care tasks. CNAs do not have a scope of practice but manage care under the guidance of the 42 CFR ? 483. There is not a clear understanding of what are the allowable delegated activities for the CNA beyond that of the basic skills. The variation of allowable care tasks per state may result in confusion of what are the overall CNA job roles or scope. This dissertation described what are the allowable delegated activities for CNAs working in nursing facility settings. Further, this work determined if there was a difference in the clinical outcomes in states that had a basic versus states that had an expanded scope of practice for CNAs, and this dissertation described the self-efficacy expectations and care tasks performed among CNAs. Findings suggest that all states within the United States allow CNAs to manage basic care tasks, and 11 states allow CNAs to manage expanded care tasks. Findings also indicate that there was no difference in clinical outcomes, specifically the outcomes of ADLs, falls with major injury, restraint use, and pain when compared to the allowable care tasks managed by CNAs in each state. Finally, CNAs who worked in states that allowed for expanded care tasks had a stronger self-efficacy for performing expanded tasks when compared to CNAs who worked in states that only allow CNAs to manage basic tasks
ANDROID MALWARE DETECTION AND CLASSIFICATION USING MACHINE LEARNING TECHNIQUES
No full textAndroid is popular mobile operating system and there are multiple marketplaces for android applications. Most of these market places allow applications to be signed using self-signed certificates. Due to this practice there exists little or very limited control over the kind of applications that are being distributed. Also advancement of android root kits is making it increasingly easier to repackage existing android applications with malicious code. Conventional signature based techniques fail to detect these malwares. So detection and classification of android malwares is a very difficult problem to solve. We present a method to classify and detect such malwares by performing dynamic analysis of the system call sequences. Here we make use of machine learning techniques to build multiple models using distributions of syscalls as features. Using these models we predict whether given application is malicious or benign. Also we try to classify given application to specific known malware family. We also explore deeplearning methods such as stacked denoising autoencoder (SdA) algorithms and its effectiveness. We experimentally evaluate our methods using a real dataset of 600 malicious applications spread across 38 malware families along with 25 popular benign applications from various areas. We find that deeplearning algorithm (SdA) is most accurate in detecting a malware with lowest false positives while AdaBoost performs better in classifying a malware family
HETEROTRIMERIC G-PROTEIN βγ SUBUNITS IN THE MOUSE PERIPHERAL OLFACTORY SYSTEM
No full textG-protein coupled signaling cascades are involved in a variety of activities in the sensory neurons of the peripheral olfactory system in mice, such as odor transduction and axonal projection. While the roles of heterotrimeric G-protein α-subunits, such as the olfactory G-protein α subunit (Gαolf) are well documented, very little is known about Gβγ subunits in the nasal sensory epithelium. Contrastingly, many studies in other systems have yielded a surge of data documenting the diverse functions of the known five Gβ and twelve Gγ subunits. Lin et al. in 2007 characterized a subset of olfactory sensory neurons in the main olfactory epithelium expressing the ion channel transient receptor potential channel (TRPM5). In other systems such as taste receptor cells, TRPM5 is a necessary downstream component of the phospholipase C (PLC) pathway which is thought to be activated by Gβγ. The heterotrimeric G-protein γ subunit Gγ13 is present in the cilia of olfactory sensory neurons (OSNs) of the main olfactory epithelium (MOE). This suggests that as an obligate dimer, Gβγ could be serving a role in the function of olfactory sensory neurons. Although Gγ13 expression was found in the MOE, there was scattered and incomplete data regarding expression of other β and γ subunits in both MOE and the vomeronasal organ (VNO). In this work, using molecular techniques I provide a complete expression profile of the 5 different Gβ and 12 Gγ subunits in the MOE and VNO. I show that multiple Gβ and Gγ subunits are expressed in the MOE and VNO in a cell type specific fashion. Additionally, using molecular techniques and image analysis, I show that Gβ1 is dominant in both MOE and VNO. Finally, using molecular and physiological approaches, I demonstrate that Gβ1 is essential to proper function of OSNs and also for glomerular formation in the main olfactory bulb (MOB). My results demonstrate the heterotrimeric G-protein βγ subunits serve critical roles in olfaction
Multigrid solution of distributed optimal control problems constrained by semilinear elliptic PDEs
No full textOptimization constrained by partial differential equations (PDEs) is a research area in which the scientific and engineering communities have seen a growing interest over the last decade. The recent rise in interest was fostered by the tremendous increase in computing power over the last twenty years. This can be attributed both to the tremendous advances in high-performance computing technologies and to its wide range of applicability. However, just growth in computing power is insufficient for tackling PDE-constrained optimization problems and there is always a need for ever-increasing efficient algorithms. The objective of this dissertation is to develop, analyze and implement multigrid preconditioners for the linear systems arising in the Newton-Krylov solution process for the nonlinear PDE constraints. Our main focus is on semilinear elliptic constraints with no additional control or state constraints. We analyze the preconditioners both theoretically and numerically. In this work we show that the multigrid preconditioners are of optimal order (p = 2) for piecewise linear finite element approximations. We also study control-constrained optimal control problems constrained by linear-elliptic equations. This problem is non-trivial from the optimization point of view as the KKT system is now a complementarity system. We employ semismooth Newton methods (SSNMs) to solve this problem efficiently. The multigrid preconditioners discussed here are extensions of preconditioners developed previously for the unconstrained case. We present some new results and techniques that yield optimal order multigrid preconditioners, at least for the case when the control is discretized using piecewise-constant finite elements
Man on a Ladder
No full textAmy_Laughlin__Vassar_College__Academic_Computing_Consultant__Man_on_a_Ladder_February_19__2014_at_1233PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Man Working on a Light Pole
No full textAmy_Laughlin__Vassar_College__Academic_Computing_Consultant__Man_Working_on_a_Light_Pole_February_19__2014_at_0144PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Untitled [Water tower collage]
No full textDaniel_Cannistra_UMBC_February_22__2014_at_0826PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe
Untitled [Band on stage behind bars]
No full textDavid_K__Kevin_David_J._Krout___UMBC__Visual_Arts_Student__Animal_Crackers_February_21__2014_at_0833PMThese images were created as part of the Hughes Remix project, a collaborative endeavor developed by UMBC's Albin O. Kuhn Library Special Collections and the Department of Visual Art to foster creative engagement with archival holdings in conjunction with the 2014 Society for Photographic Education annual conference. UMBC's Special Collections offered a selection of images from the Hughes Company Glass Negatives (http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughes) collection for SPE members and conference attendees to remix, reinvent, reinterpret, and reimagine the images in this collection of Baltimore street scenes, promotional and advertising photographs, businesses, churches, schools, monuments, factories, machinery, and portraits. Images that were created were displayed during the conference as well as on a Tumblr site and are now archived in the Special Collections. Full details of the project can be found at: http://hughes-remix.tumblr.com/overview.The original Hughes Company Glass Negatives collection can be found at: http://contentdm.ad.umbc.edu/cdm/landingpage/collection/hughe