283 research outputs found

    Bait and Snitch: Defending Computer Systems with Decoys

    Get PDF
    Threats against computer networks continue to multiply, but existing security solutions are persistently unable to keep pace with these challenges. In this paper we present a new paradigm for securing computational resources which we call decoy technology. This technique involves seeding a system with data that appears authentic but is in fact spurious. Attacks can then be detected by monitoring this phony information for access events. Decoys are capable of detecting malicious activity, such as insider and masquerade attacks, that are beyond the scope of traditional security measures. They can be used to address confidentiality breaches either proactively or after they have taken place. This work examines the challenges that must be overcome in order to successfully deploy decoys as part of a comprehensive security solution. It discusses situations where decoys are particularly useful as well as characteristics that effective decoy material should share. Furthermore, we describe the tools that we have developed to efficiently craft and distribute decoys in order to form a network of sensors that is capable of detecting adversarial action that occurs anywhere in an organizations system

    Numerical inversion of SRNFs for efficient elastic shape analysis of star-shaped objects

    Get PDF
    The elastic shape analysis of surfaces has proven useful in several application areas, including medical image analysis, vision, and graphics. This approach is based on defining new mathematical representations of parameterized surfaces, including the square root normal field (SRNF), and then using the L2 norm to compare their shapes. Past work is based on using the pullback of the L2 metric to the space of surfaces, performing statistical analysis under this induced Riemannian metric. However, if one can estimate the inverse of the SRNF mapping, even approximately, a very efficient framework results: the surfaces, represented by their SRNFs, can be efficiently analyzed using standard Euclidean tools, and only the final results need be mapped back to the surface space. Here we describe a procedure for inverting SRNF maps of star-shaped surfaces, a special case for which analytic results can be obtained. We test our method via the classification of 34 cases of ADHD (Attention Deficit Hyperactivity Disorder), plus controls, in the Detroit Fetal Alcohol and Drug Exposure Cohort study. We obtain state-of-the-art results

    How to humiliate and shame: A reporter's guide to the power of the mugshot

    Get PDF
    This is an Author's Accepted Manuscript of an article published in Social Semiotics, 24(1), 56-87, 2014, copyright Taylor & Francis, available online at: http://www.tandfonline.com/The judicial photograph – the “mugshot” – is a ubiquitous and instantly recognisable form, appearing in the news media, on the internet, on book covers, law enforcement noticeboards and in many other mediums. This essay attempts to situate the mugshot in a historical and theoretical context to explain the explicit and implicit meaning of the genre as it has developed, focussing in particular on their use in the UK media in late modernity. The analysis is based on the author's reflexive practice as a journalist covering crime in the national news media for 30 years and who has used mugshots to illustrate stories for their explicit and specific content. The author argues that the visual limitations of the standardised “head and shoulders” format of the mugshot make it a robust subject for analysing the changing meaning of images over time. With little variation in the image format, arguments for certain accreted layers of signification are easier to make. Within a few years of the first appearance of the mugshot form in the mid-19th century, it was adopted and adapted as a research tool by scientists and criminologists. While the positivist scientists claimed empirical objectivity we can now see that mugshots played a part in the construction of subjective notions of “the other”, “the lesser” or “sub-human” on the grounds of class, race and religion. These dehumanising ideas later informed the theorists and bureaucrats of National Socialist ideology from the 1920s to 1940s. The author concludes that once again the mugshot has become, in certain parts of the media, a signifier widely used to exclude or deride certain groups. In late modernity, the part of the media that most use mugshots – the tabloid press and increasingly tabloid TV – is part of a neo-liberal process that, in a conscious commercial appeal to the paying audience, seeks to separate rather than unify wider society

    Pilot Study Assessment of Dynamic Vascular Changes in Breast Cancer with Near-Infrared Tomography from Prospectively Targeted Manipulations of Inspired End-Tidal Partial Pressure of Oxygen and Carbon Dioxide

    Get PDF
    The dynamic vascular changes in the breast resulting from manipulation of both inspired end-tidal partial pressure of oxygen and carbon dioxide were imaged using a 30 s per frame frequency-domain near-infrared spectral (NIRS) tomography system. By analyzing the images from five subjects with asymptomatic mammography under different inspired gas stimulation sequences, the mixture that maximized tissue vascular and oxygenation changes was established. These results indicate maximum changes in deoxy-hemoglobin, oxygen saturation, and total hemoglobin of 21, 9, and 3%, respectively. Using this inspired gas manipulation sequence, an individual case study of a subject with locally advanced breast cancer undergoing neoadjuvant chemotherapy (NAC) was analyzed. Dynamic NIRS imaging was performed at different time points during treatment. The maximum tumor dynamic changes in deoxy-hemoglobin increased from less than 7% at cycle 1, day 5 (C1, D5) to 17% at (C1, D28), which indicated a complete response to NAC early during treatment and was subsequently confirmed pathologically at the time of surgery

    Macroscopic Optical Imaging Technique for Wide-Field Estimation of Fluorescence Depth in Optically Turbid Media for Application in Brain Tumor Surgical Guidance

    Get PDF
    A diffuse imaging method is presented that enables wide-field estimation of the depth of fluorescent molecular markers in turbid media by quantifying the deformation of the detected fluorescence spectra due to the wavelength-dependent light attenuation by overlying tissue. This is achieved by measuring the ratio of the fluorescence at two wavelengths in combination with normalization techniques based on diffuse reflectance measurements to evaluate tissue attenuation variations for different depths. It is demonstrated that fluorescence topography can be achieved up to a 5 mm depth using a near-infrared dye with millimeter depth accuracy in turbid media having optical properties representative of normal brain tissue. Wide-field depth estimates are made using optical technology integrated onto a commercial surgical microscope, making this approach feasible for real-world applications

    Vibrational spectroscopy: a promising approach to discriminate neurodegenerative disorders

    Get PDF
    Neurodegenerative diseases are a growing burden in modern society, thus crucially calling for the development of accurate diagnostic strategies. These diseases are currently incurable, a fact which has been attributed to their late diagnosis, after brain damage has already become widespread. An earlier and improved diagnosis is necessary for the enrolment of patients into clinical trials and can pave the way for the development of therapeutic tactics. Novel analytical techniques, such as mass spectrometry and vibrational spectroscopy, have been able to successfully detect and characterise neurodegenerative disorders. It is critical to globally support and make use of innovative basic research and techniques, which could ultimately lead to the creation of a cost-effective diagnostic test. Minimally invasive samples, such as biological fluids, have also been shown to reveal information for these diseases; utilising them could simplify sample collection/analysis and be more preferable to patients

    Macroscopic-Imaging Technique for Subsurface Quantification of Near-Infrared Markers During Surgery

    Get PDF
    Obtaining accurate quantitative information on the concentration and distribution of fluorescent markers lying at a depth below the surface of optically turbid media, such as tissue, is a significant challenge. Here, we introduce a fluorescence reconstruction technique based on a diffusion light transport model that can be used during surgery, including guiding resection of brain tumors, for depth-resolved quantitative imaging of near-infrared fluorescent markers. Hyperspectral fluorescence images are used to compute a topographic map of the fluorophore distribution, which yields structural and optical constraints for a three-dimensional subsequent hyperspectral diffuse fluorescence reconstruction algorithm. Using the model fluorophore Alexa Fluor 647 and brain-like tissue phantoms, the technique yielded estimates of fluorophore concentration within ±25% of the true value to depths of 5 to 9 mm, depending on the concentration. The approach is practical for integration into a neurosurgical fluorescence microscope and has potential to further extend fluorescence-guided resection using objective and quantified metrics of the presence of residual tumor tissue

    A geometric approach to visualization of variability in functional data

    Get PDF
    We propose a new method for the construction and visualization of boxplot-type displays for functional data. We use a recent functional data analysis framework, based on a representation of functions called square-root slope functions, to decompose observed variation in functional data into three main components: amplitude, phase, and vertical translation. We then construct separate displays for each component, using the geometry and metric of each representation space, based on a novel definition of the median, the two quartiles, and extreme observations. The outlyingness of functional data is a very complex concept. Thus, we propose to identify outliers based on any of the three main components after decomposition. We provide a variety of visualization tools for the proposed boxplot-type displays including surface plots. We evaluate the proposed method using extensive simulations and then focus our attention on three real data applications including exploratory data analysis of sea surface temperature functions, electrocardiogram functions and growth curves
    • 

    corecore