640 research outputs found

    Student Demographic And Academic Characteristics That Predict Community College Student Success In Online Courses

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    Online student success is a concern for higher education institutions especially community colleges with open enrollment admission. This study analyzed online student success using online GPA (dependent variable) and both demographic and academic characteristics of online students (independent variables) to determine which characteristics significantly correlated to and predicted student success in online courses. The sample included an unduplicated count of 4,046 online students enrolled in at least one online course during fall 2015 and spring 2016 at a public, Midwestern community college. Six research questions and twelve hypotheses were used to determine which independent variables led online students to a higher online GPA. Analysis was completed separately for students taking at least one online course and students taking only online courses using descriptive statistics, t tests, correlation coefficients, cross-tabulations, and logistic regression. The most significant finding was a large, positive relationship between cumulative GPA and online GPA. There was also a significant, positive correlation between online GPA and cumulative credit hours as well as online GPA and number of online courses taken. There was a significant, negative correlation between online GPA and course withdrawals. Additionally, a higher online GPA was identified for older, female, and White online students while a lower online GPA was found for Black online students. Findings also indicated a significant difference in online GPA for both online student groups based on computer experience and remedial coursework along with a significant difference in online GPA just for online only students based on financial aid

    Double-Compressed JPEG Detection in a Steganalysis System

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    The detection of hidden messages in JPEG images is a growing concern. Current detection of JPEG stego images must include detection of double compression: a JPEG image is double compressed if it has been compressed with one quality factor, uncompressed, and then re-compressed with a different quality factor. When detection of double compression is not included, erroneous detection rates are very high. The main contribution of this paper is to present an efficient double-compression detection algorithm that has relatively lower dimensionality of features and relatively lower computational time for the detection part, than current comparative classifiers. We use a model-based approach for creating features, using a subclass of Markov random fields called partially ordered Markov models (POMMs) to modeling the phenomenon of the bit changes that occur in an image after an application of steganography. We model as noise the embedding process, and create features to capture this noise characteristic. We show that the nonparametric conditional probabilities that are modeled using a POMM can work very well to distinguish between an image that has been double compressed and one that has not, with lower overall computational cost. After double compression detection, we analyze histogram patterns that identify the primary quality compression factor to classify the image as stego or cover. The latter is an analytic approach that requires no classifier training. We compare our results with another state-of-the-art double compression detector. Keywords: steganalysis; steganography; JPEG; double compression; digital image forensics

    CANVASS - A Steganalysis Forensic Tool for JPEG Images

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    Steganography is a way to communicate a message such that no one except the sender and recipient suspects the existence of the message. This type of covert communication lends itself to a variety of different purposes such as spy-to-spy communication, exchange of pornographic material hidden in innocuous image files, and other illicit acts. Computer forensic personnel have an interest in testing for possible steganographic files, but often do not have access to the technical and financial resources required to perform steganalysis in an effective manner. This paper describes the results of a funded effort by a grant from the National Institutes of Justice to develop a user friendly and practical software program that has been designed to meet the steganalysis needs of the Iowa Division of Criminal Investigation in Ankeny, Iowa. The software performs steganalysis on JPEG image files in an efficient and effective way. JPEG images are popular and used by a great many people, and thus are naturally exploited for steganography. The commercial software that is available for detection of hidden messages is often expensive and does not fit the need of smaller police forensic labs. Our software checks for the presence of hidden payloads for five different JPEG-embedding steganography algorithms with the potential of identifying stego images generated by other (possibly unknown) embedding algorithm. Keywords: steganography, steganalysis, JPEG images, GUI softwar

    Environmental Circadian Disruption Elevates the IL-6 Response to Lipopolysaccharide in Blood

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    The immune system is regulated by circadian clocks within the brain and immune cells. Environmental circadian disruption (ECD), consisting of a 6-h phase advance of the light:dark cycle once a week for 4 weeks, elevates the inflammatory response to lipopolysaccharide (LPS) both in vivo and in vitro. This indicates that circadian disruption adversely affects immune function; however, it remains unclear how the circadian system regulates this response under ECD conditions. Here, we develop an assay using ex vivo whole-blood LPS challenge to investigate the circadian regulation of immune responses in mice and to determine the effects of ECD on these rhythms. LPS-induced IL-6 release in whole blood was regulated in a circadian manner, peaking during subjective day under both entrained and free-running conditions. This LPS-induced IL-6 release rhythm was associated with daily variation in both white blood cell counts and immune cell responsiveness. ECD increased the overall level of LPS-induced IL-6 release by increasing immune cell responsiveness and not by affecting immune cell number or the circadian regulation of this rhythm. This indicates that ECD produces pathological immune responses by increasing the proinflammatory responses of immune cells. Also, this newly developed whole blood assay can provide a noninvasive longitudinal method to quantify potential health consequences of circadian disruption in humans

    The de Morton Mobility Index (DEMMI): An essential health index for an ageing world

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    BACKGROUND: Existing instruments for measuring mobility are inadequate for accurately assessing older people across the broad spectrum of abilities. Like other indices that monitor critical aspects of health such as blood pressure tests, a mobility test for all older acute medical patients provides essential health data. We have developed and validated an instrument that captures essential information about the mobility status of older acute medical patients. METHODS: Items suitable for a new mobility instrument were generated from existing scales, patient interviews and focus groups with experts. 51 items were pilot tested on older acute medical inpatients. An interval-level unidimensional mobility measure was constructed using Rasch analysis. The final item set required minimal equipment and was quick and simple to administer. The de Morton Mobility Index (DEMMI) was validated on an independent sample of older acute medical inpatients and its clinimetric properties confirmed. RESULTS: The DEMMI is a 15 item unidimensional measure of mobility. Reliability (MDC(90)), validity and the minimally clinically important difference (MCID) of the DEMMI were consistent across independent samples. The MDC(90) and MCID were 9 and 10 points respectively (on the 100 point Rasch converted interval DEMMI scale). CONCLUSION: The DEMMI provides clinicians and researchers with a valid interval-level method for accurately measuring and monitoring mobility levels of older acute medical patients. DEMMI validation studies are underway in other clinical settings and in the community. Given the ageing population and the importance of mobility for health and community participation, there has never been a greater need for this instrument

    Atomic spectrometry update : a review of advances in environmental analysis

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    This is the 31st annual review of the application of atomic spectrometry to the chemical analysis of environmental samples. This update refers to papers published approximately between August 2014 and July 2015 and continues the series of Atomic Spectrometry Updates (ASUs) in Environmental Analysis that should be read in conjunction with other related ASUs in the series, namely: clinical and biological materials, foods and beverages; advances in atomic spectrometry and related techniques; elemental speciation; X-ray spectrometry; and metals, chemicals and functional materials. In the field of air analysis, highlights within this review period included: the development of a new laser fluorescence instrument for the ultratrace determination of mercury vapour; single particle ICP-MS studies and the coupling of elemental analysers to mass spectrometers for the improved characterisation of carbonaceous aerosols. In the arena of water analysis, methods continue to be developed: for the extraction and preconcentration of elements, As, Cr, Hg and Sb species and determination of elemental constituents in colloidal and NP fractions. Emerging elements of interest include Gd derived from MRI agents discharged at low level from medical facilities in water courses. Instrumental developments reported included the use of MC-ICP-MS for isotopic tracer studies and a review of TXRF techniques and associated preconcentration procedures for trace element analysis. In the period covered by this update several articles have explored the analysis of soil extracts for geochemical prospecting. There has been widening interest in the use of CS-AAS and in the application of techniques capable of direct sample analysis such as slurry sampling ETAAS and ETV-ICP-AES. Portable XRF instrumentation is now being used in many disciplines to quantify trace elements in soils – bringing a need for better transfer of analytical knowledge to non-specialist users – and the growing use of portable XRF in proximal sensing is also noteworthy. Recent research indicates that geological applications still drive many of the instrumental and methodological advances in LA-ICP-MS. Fundamental studies continued to shed light on the processes involved and hence ways of improving the analysis of laser-produced aerosols and to minimise matrix and fractionation effects. A new technique LA-DOF-MS (distance of flight) was described. The utility of LIBS and portable XRF for in situ survey work continues to show promise but issues such as appropriate calibration regimes and data processing protocols will still need to be addressed

    HISSbot: Sidewinding with a Soft Snake Robot

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    Snake robots are characterized by their ability to navigate through small spaces and loose terrain by utilizing efficient cyclic forms of locomotion. Soft snake robots are a subset of these robots which utilize soft, compliant actuators to produce movement. Prior work on soft snake robots has primarily focused on planar gaits, such as undulation. More efficient spatial gaits, such as sidewinding, are unexplored gaits for soft snake robots. We propose a novel means of constructing a soft snake robot capable of sidewinding, and introduce the Helical Inflating Soft Snake Robot (HISSbot). We validate this actuation through the physical HISSbot, and demonstrate its ability to sidewind across various surfaces. Our tests show robustness in locomotion through low-friction and granular media.Comment: 7 pages, 9 figures, to be published in RoboSoft 202
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