158 results on '"A. Karnowski"'
Search Results
2. Quality Assessment of Retinal Fundus Images using Elliptical Local Vessel Density
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Thomas P. Karnowski, Kenneth W. Tobin, Fabrice Meriaudeau, Luca Giancardo, and Edward Chaum
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education.field_of_study ,business.industry ,Image quality ,Population ,Field of view ,Diabetic retinopathy ,medicine.disease ,Cardinal point ,Software ,Outlier ,medicine ,Computer vision ,Artificial intelligence ,business ,education ,Retinopathy - Abstract
Diabetic retinopathy is the leading cause of blindness in the Western world. The World Health Organisation estimates that 135 million people have diabetes mellitus worldwide and that the number of people with diabetes will increase to 300 million by the year 2025 (Amos et al., 1997). Timely detection and treatment for DR prevents severe visual loss in more than 50% of the patients (ETDRS, 1991). Through computer simulations is possible to demonstrate that prevention and treatment are relatively inexpensive if compared to the health care and rehabilitation costs incurred by visual loss or blindness (Javitt et al., 1994). The shortage of ophthalmologists and the continuous increase of the diabetic population limits the screening capability for effective timing of sight-saving treatment of typical manual methods. Therefore, an automatic or semi-automatic system able to detect various type of retinopathy is a vital necessity to save many sight-years in the population. According to Luzio et al. (2004) the preferred way to detect diseases such as diabetic retinopathy is digital fundus camera imaging. This allows the image to be enhanced, stored and retrieved more easily than film. In addition, images may be transferred electronically to other sites where a retinal specialist or an automated system can detect or diagnose disease while the patient remains at a remote location. Various systems for automatic or semi-automatic detection of retinopathy with fundus images have been developed. The results obtained are promising but the initial image quality is a limiting factor (Patton et al., 2006); this is especially true if the machine operator is not a trained photographer. Algorithms to correct the illumination or increase the vessel contrast exist (Chen & Tian, 2008; Foracchia et al., 2005; Grisan et al., 2006;Wang et al., 2001), however they cannot restore an image beyond a certain level of quality degradation. On the other hand, an accurate quality assessment algorithm can allow operators to avoid poor images by simply re-taking the fundus image, eliminating the need for correction algorithms. In addition, a quality metric would permit the automatic submission of only the best images if many are available. The measurement of a precise image quality index is not a straightforward task, mainly because quality is a subjective concept which varies even between experts, especially for images that are in the middle of the quality scale. In addition, image quality is dependent upon the type of diagnosis being made. For example, an image with dark regions might be considered of good quality for detecting glaucoma but of bad quality for detecting diabetic retinopathy. For this reason, we decided to define quality as the 'characteristics of an image that allow the retinopathy diagnosis by a human or software expert'. Fig. 1 shows some examples of macula centred fundus images whose quality is very likely to be judged as poor by many ophthalmologists. The reasons for this vary. They can be related to the camera settings like exposure or focal plane error (Fig. 1.(a,e,f)), the camera condition like a dirty or shuttered lens (Fig. 1.(d,h)), the movements of the patient which might blur the image (Fig. 1.(c)) or if the patient is not in the field of view of the camera (Fig. 1.(g)). We define an outlier as any image that is not a retina image which could be submitted to the screening system by mistake. Existing algorithms to estimate the image quality are based on the length of visible vessels in the macula region (Fleming et al., 2006), or edges and luminosity with respect to a reference image (Lalonde et al., 2001; Lee & Wang, 1999). Another method uses an unsupervised classifier that employs multi-scale filterbanks responses (Niemeijer et al., 2006). The shortcomings of these methods are either the fact that they do not take into account the natural variance encountered in retinal images or that they require a considerable time to produce a result. Additionally, none of the algorithms in the literature that we surveyed generate a 'quality measure'. Authors tend to split the quality levels into distinct classes and to classify images in particular ones. This approach is not really flexible and is error prone. In fact human experts are likely to disagree if many categories of image quality are used. Therefore, we think that a normalized 'quality measure' from 0 to 1 is the ideal way to approach the classification problem. Processing speed is another aspect to be taken into consideration. While algorithms to assess the disease state of the retina do not need to be particularly fast (within reason), the time response of the quality evaluation method is key towards the development of an automatic retinopathy screening system.
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- 2021
3. Corrections of axial shift artifact in dynamic swept-source optical coherence tomography
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Angela Pachacz, Onur Cetinkaya, Andrea Curatolo, Susana Marcos, Alejandra Consejo, Jędrzej Solarski, Maciej Wojtkowski, and Karol Karnowski
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Physics ,Artifact (error) ,genetic structures ,medicine.diagnostic_test ,business.industry ,Computer Science::Information Retrieval ,Physics::Medical Physics ,Phase (waves) ,Physics::Optics ,Laser ,Computer Science::Digital Libraries ,Bulk motion ,Sample (graphics) ,law.invention ,Interferometry ,Optics ,Optical coherence tomography ,Computer Science::Computational Engineering, Finance, and Science ,law ,Motion artifacts ,medicine ,business - Abstract
Image artifacts due to the bulk motion of the sample are well known and described. Some methods of correction in Full-Filed Swept-Source OCT were presented. For the measurement of dynamic sample motion, the axial motion artifacts can significantly influence measured signals. Here, we investigate the axial shift phenomena for measurements with low cost, reduced speed swept laser. Simulation results have led us to the way of correction of the axial shift artifact by manipulation of the phase of OCT fringes. Results of disturbed and undisturbed measurement of vibrating speaker membrane or induced deformations of the porcine eye are presented.
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- 2021
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4. Dynamic light scattering improves imaging with optical coherence tomography
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Klaudia Nowacka, Karol Karnowski, Maciej Wojtkowski, and Dawid Borycki
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Physics ,genetic structures ,medicine.diagnostic_test ,Scattering ,business.industry ,Physics::Medical Physics ,Resolution (electron density) ,Speckle noise ,Particle displacement ,eye diseases ,Speckle pattern ,Optics ,Optical coherence tomography ,medicine ,sense organs ,business ,Image resolution ,Coherence (physics) - Abstract
Optical coherence tomography (OCT) is a well-established modality for structural and functional imaging of the biological samples. Conventional scanning OCT combines the low temporal coherence with confocal gating to reject multiply scattered light. However, OCT uses a spatially coherent light source, and thus, is susceptible to speckle noise, which reduces the transverse resolution. We use dynamic light scattering to improve the transverse resolution. The dynamic scattering particles induce speckles, that change over time due to particle displacement. By incoherently averaging OCT images acquired under different particle distributions, we effectively suppress the spatial coherence and improve transverse image resolution.
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- 2021
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5. Corrections of motion artifacts in dynamic low-cost, swept-source optical coherence tomography
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Susana Marcos, Karol Karnowski, Angela Pachacz, Alejandra Consejo, Jędrzej Solarski, Onur Cetinkaya, Andrea Curatolo, and Maciej Wojtkowski
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Physics ,Optics ,genetic structures ,Optical coherence tomography ,medicine.diagnostic_test ,Image quality ,Motion artifacts ,business.industry ,medicine ,sense organs ,business ,Laser ranging ,eye diseases - Abstract
OCT imaging of dynamic samples can give rise to significant misleading axial motion artifacts, depending on system specifications. Here, we investigate the axial shift phenomena in low-cost swept-source OCT dynamic measurements and simulations.
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- 2021
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6. An Integrated Platform for Collaborative Data Analytics
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Thomas P. Karnowski, Sean Oesch, and Robert E. Gillen
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Data sharing ,Computer science ,Analytics ,business.industry ,Dashboard (business) ,Data analysis ,Key (cryptography) ,Web application ,Computational environment ,business ,Data science ,Knowledge sharing - Abstract
While collaboration among data scientists is a key to organizational productivity, data analysts face significant barriers to achieving this end, including data sharing, accessing and configuring the required computational environment, and a unified method of sharing knowledge. Each of these barriers to collaboration is related to the fundamental question of knowledge management “how can organizations use knowledge more effectively?”. In this paper, we consider the problem of knowledge management in collaborative data analytics and present ShareAL, an integrated knowledge management platform, as a solution to that problem. The ShareAL platform consists of three core components: a full stack web application, a dashboard for analyzing streaming data and a High Performance Computing (HPC) cluster for performing real time analysis. Prior research has not applied knowledge management to collaborative analytics or developed a platform with the same capabilities as ShareAL. ShareAL overcomes the barriers data scientists face to collaboration by providing intuitive sharing of data and analytics via the web application, a shared computing environment via the HPC cluster and knowledge sharing and collaboration via a real time messaging application.
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- 2020
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7. Using Low-Cost 'Garage Band' Recording Technology for Acquiring High Resolution High-Speed Data
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Michael R. Moore, Eva Freer, Ryan A. Kerekes, Gregory S. Sheets, Michael Vann, Randall Wetherington, and Thomas P. Karnowski
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Sound recording and reproduction ,Software ,High fidelity ,Data acquisition ,business.industry ,Computer science ,Systems architecture ,Oak Ridge National Laboratory ,business ,High Flux Isotope Reactor ,Computer hardware ,Communication channel - Abstract
The Oak Ridge National Laboratory (ORNL) has developed and tested a novel system architecture for acquiring high fidelity high-speed data. The approach uses a consumer grade audio recording device that is normally associated with “garage band” recording of music. ORNL has coupled this low-cost data acquisition hardware with computing technology running open-source software. The main advantage of this approach is per-channel cost; an instrument grade data acquisition system typically costs between $800 to $2000 per channel compared to less than $50 per channel for these consumer grade components. Three systems, each featuring four channels, have been deployed for acquiring data from geophones and the electrical supply system that supports the High Flux Isotope Reactor (HFIR) and the Radiochemical Engineering Development Center (REDC) at ORNL. Each channel samples at 96 kHz at 24-bit resolution. The deployed systems operate continuously 24/7 and produce about 4 terabytes of data per month per system. This paper provides a technical overview of this approach, its implementation, and some preliminary results from qualification testing. This work was conducted in support of the Multi-Informatics for Nuclear Operations Scenarios (MINOS).
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- 2020
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8. Jones matrix‐based speckle‐decorrelation angiography using polarization‐sensitive optical coherence tomography
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Qingyun Li, Qiang Wang, David D. Sampson, Peijun Gong, and Karol Karnowski
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Scanner ,Computer science ,Image quality ,media_common.quotation_subject ,General Physics and Astronomy ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,010309 optics ,Matrix (mathematics) ,Optics ,Optical coherence tomography ,0103 physical sciences ,medicine ,Contrast (vision) ,General Materials Science ,Projection (set theory) ,media_common ,medicine.diagnostic_test ,business.industry ,010401 analytical chemistry ,Angiography ,General Engineering ,General Chemistry ,Speckle decorrelation ,0104 chemical sciences ,business ,Tomography, Optical Coherence - Abstract
We show that polarization-sensitive optical coherence tomography angiography (PS-OCTA) based on full Jones matrix assessment of speckle decorrelation offers improved contrast and depth of vessel imaging over conventional OCTA. We determine how best to combine the individual Jones matrix elements and compare the resulting image quality to that of a conventional OCT scanner by co-locating and imaging the same skin locations with closely matched scanning setups. Vessel projection images from finger and forearm skin demonstrate the benefits of Jones matrix-based PS-OCTA. Our study provides a promising starting point and a useful reference for future pre-clinical and clinical applications of Jones matrix-based PS-OCTA.
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- 2020
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9. A Dimensionally Aligned Signal Projection for Classification of Unintended Radiated Emissions
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Ryan A. Kerekes, Corey D. Cooke, Thomas P. Karnowski, Adam L. Anderson, and Jason M. Vann
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Engineering ,business.industry ,Nonintrusive load monitoring ,020208 electrical & electronic engineering ,Feature extraction ,020206 networking & telecommunications ,Pattern recognition ,Ranging ,02 engineering and technology ,Condensed Matter Physics ,Signal ,Atomic and Molecular Physics, and Optics ,Electromagnetic interference ,Feature (computer vision) ,0202 electrical engineering, electronic engineering, information engineering ,Electronic engineering ,Leverage (statistics) ,Artificial intelligence ,Electrical and Electronic Engineering ,business ,Projection (set theory) - Abstract
Characterization of unintended radiated emissions (URE) from electronic devices plays an important role in many research areas from electromagnetic interference to nonintrusive load monitoring to information system security. URE can provide insights for applications ranging from load disaggregation and energy efficiency to condition-based maintenance of equipment-based upon detected fault conditions. URE characterization often requires subject matter expertise to tailor transforms and feature extractors for the specific electrical devices of interest. We present a novel approach, named dimensionally aligned signal projection (DASP), for projecting aligned signal characteristics that are inherent to the physical implementation of many commercial electronic devices. These projections minimize the need for an intimate understanding of the underlying physical circuitry and significantly reduce the number of features required for signal classification. We present three possible DASP algorithms that leverage frequency harmonics, modulation alignments, and frequency peak spacings, along with a two-dimensional image manipulation method for statistical feature extraction. To demonstrate the ability of DASP to generate relevant features from URE, we measured the conducted URE from 14 residential electronic devices using a 2 MS/s collection system. A linear discriminant analysis classifier was trained using DASP generated features and was blind tested resulting in a greater than 90% classification accuracy for each of the DASP algorithms and an accuracy of 99.1% when DASP features are used in combination. Furthermore, we show that a rank reduced feature set of the combined DASP algorithms provides a 98.9% classification accuracy with only three features and outperforms a set of spectral features in terms of general classification as well as applicability across a broad number of devices.
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- 2018
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10. From incidental news exposure to news engagement. How perceptions of the news post and news usage patterns influence engagement with news articles encountered on Facebook
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Larissa Leonhard, Veronika Karnowski, Dominik J. Leiner, and Anna Sophie Kümpel
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Experience sampling method ,Social network ,business.industry ,media_common.quotation_subject ,InformationSystems_INFORMATIONSTORAGEANDRETRIEVAL ,05 social sciences ,Internet privacy ,050801 communication & media studies ,0506 political science ,Human-Computer Interaction ,0508 media and communications ,Arts and Humanities (miscellaneous) ,Feeling ,Perception ,050602 political science & public administration ,InformationSystems_MISCELLANEOUS ,business ,Psychology ,General Psychology ,media_common - Abstract
On social network sites (SNS), people are increasingly confronted with news content—even if they have not actively been looking for it. Although it is widely recognized that SNS have become a main driver for such incidental news exposure, we know little about the factors that influence whether users engage with news encountered on SNS. Thus, this study investigates under which conditions incidental news exposure becomes actual engagement with news by asking how both the perception of the news post and general news usage patterns influence the intention to read news articles encountered on SNS as well as the intention to look for further information about the covered issues. Building on a mobile forced experience sampling study consisting of 840 Facebook news encounters reported from 124 participants, we find that news engagement is mostly determined by participants' perceived interestingness of and prior knowledge about the issue of the news post and to a much lesser degree by social factors unique to SNS (i.e., feelings towards the spreader of the news). In contrast, no influence of content-independent news usage patterns on news engagement could be observed.
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- 2017
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11. Keratoconus detection based on a single scheimpflug image
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Karol Karnowski, Jędrzej Solarski, Maciej Wojtkowski, D. Robert Iskander, Jos J. Rozema, and Alejandra Consejo
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0301 basic medicine ,Keratoconus ,medicine.medical_specialty ,genetic structures ,keratoconus ,Scheimpflug principle ,Biomedical Engineering ,Sensitivity and Specificity ,Article ,image statistical analysis ,Cornea ,03 medical and health sciences ,0302 clinical medicine ,Ophthalmology ,Medicine ,Humans ,Sensitivity (control systems) ,Receiver operating characteristic ,business.industry ,Corneal Diseases ,Corneal Topography ,corneal visualization Scheimpflug technology ,medicine.disease ,Control subjects ,eye diseases ,Light intensity ,030104 developmental biology ,medicine.anatomical_structure ,ROC Curve ,030221 ophthalmology & optometry ,keratoconus detection ,sense organs ,Human medicine ,business - Abstract
Purpose To introduce a new approach for keratoconus detection based on corneal microstructure observed in vivo derived from a single Scheimpflug image. Methods Scheimpflug single-image snapshots from 25 control subjects and 25 keratoconus eyes were analyzed; from each group, five subjects were randomly selected to provide out-of-sample data. Each corneal image was segmented, after which the stromal pixel intensities were statistically modeled with a Weibull distribution. Distribution estimated parameters α and β, characterizing corneal microstructure, were used in combination with a macrostructure parameter, central corneal thickness (CCT), for the detection of keratoconus. In addition, receiver operating characteristic curves were used to determine the sensitivity and specificity of each parameter for keratoconus detection. Results The combination of CCT (sensitivity = 88%; specificity = 84%) with microscopic parameters extracted from statistical modeling of light intensity distribution, α (sensitivity = 76%; specificity = 76%) and β (sensitivity = 96%; specificity = 88%), from a single Scheimpflug image was found to be a successful tool to differentiate between keratoconus and control eyes with no misclassifications (sensitivity = 100%; specificity = 100%) with coefficients of variation up to 2.5%. Conclusions The combination of microscopic and macroscopic corneal parameters extracted from a static Scheimpflug image is a promising, non-invasive tool to differentiate corneal diseases without the need to perform measurements based on induced deformation of the corneal structure. Translational Relevance The proposed methodology has the potential to support clinicians in the detection of keratoconus, without compromising patient comfort.
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- 2020
12. The Nano Level of Media Use: Situational Influences on (Mobile) Media Use
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Veronika Karnowski
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Mobile media ,business.industry ,Computer science ,Media use ,Context (language use) ,Situational ethics ,business ,Data science ,Mass media - Abstract
The past two decades have witnessed tremendous change in our media ecologies, with one big trend among those changes being the rise of mobile media. Using these devices is not tied to any given location but they can be carried along with their users, enabling media use in nearly each and every context and situation in our everyday lives. Hence, the situational context of media use has become of theoretically unlimited variability, raising the interest in studying its influences on media use. But of course, context of media use had been studied already before the rise of mobile media. This chapter therefore sets out to first introduce situational dimensions already integrated in the study of traditional mass media use. Based on this we review current attempts to integrate situational characteristics into the study of mobile media use as well as methodological approaches to capture situational aspects of media use.
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- 2020
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13. Advantages and limitations of all-fiber quasi-Bessel beam probes: theory and practice (Conference Presentation)
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Michael J. Hackmann, David D. Sampson, Onur Cetinkaya, Gavrielle R. Untracht, and Karol Karnowski
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Optical fiber ,Computer science ,business.industry ,Gaussian ,law.invention ,symbols.namesake ,Optics ,law ,symbols ,Bessel beam ,Miniaturization ,Systems design ,business ,Fresnel diffraction ,Beam (structure) ,Gaussian beam - Abstract
Non-Gaussian beams can provide extended depth of focus (DOF) at constant and potentially uncompromised transverse resolution, as well as a degree of self-reconstruction after beam shadowing, which may be present in tissue imaging. Hence such beams are being developed for imaging systems throughout many disciplines, including endoscopic imaging, where they hold great potential. General possibilities include up to more than 20-fold extension of DOF, tunable working distance, imaging around obstacles and integrated all-fiber designs. In all-fiber based optical imaging systems; however, these advantages are limited by system design considerations. Trade-offs between miniaturization, extended DOF, SNR, and fiber availability arise, and estimating the effects of design modifications can be difficult and time consuming. We model zero-order quasi-Bessel illumination and detection for a range of common probe and sample materials based on an analytic solution of the Fresnel diffraction integral and compare the results to Gaussian beams. We show that these beams, on scales that match optical fiber dimensions, generally have an upper limit for the spot size above which their distinct advantages over Gaussian beams fade. Similarly, we show the existence of a lower limit of practical performance of quasi-Bessel beams, where the imaging SNR penalty compared to a Gaussian beam becomes significant. Additionally to general theoretic considerations we discuss designs, modeling and characterization of all-fiber imaging probes. This work provides an accessible overview for researchers to estimate what potential benefit non-Gaussian beams can introduce into their optical imaging system.
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- 2019
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14. Imaging the small with the small: Prospects for photonics in micro-endomicroscopy for minimally invasive cellular-resolution bioimaging
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David D. Sampson, Gavrielle R. Untracht, and Karol Karnowski
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Computer Networks and Communications ,business.industry ,Computer science ,Disease progression ,Data science ,Atomic and Molecular Physics, and Optics ,TA1501-1820 ,Endoscopic imaging ,Small lens ,Cellular resolution ,Medical imaging ,Endomicroscopy ,Applied optics. Photonics ,Photonics ,business ,Engineered tissue - Abstract
Many bioimaging studies, including those in engineered tissue constructs, intravital microscopy in animal models, and medical imaging in humans, require cellular-resolution imaging of structures deep within a sample. Yet, many of the current approaches are limited in terms of resolution, but also in invasiveness, repeatable imaging of the same location, and accessible imaging depth. We coin the term micro-endomicroscope to describe the emerging class of small, cellular-resolution endoscopic imaging systems designed to image cells in situ while minimizing perturbation of the sample. In this Perspective, we motivate the need for further development of micro-endomicroscopes, highlighting applications that would greatly benefit, reviewing progress, and considering how photonics might contribute. We identify areas ripe for technological development, such as micro-scanners and small lens systems, that would advance micro-endomicroscope performance. With the right developments in photonics, many possibilities exist for new minimally invasive translatable imaging tools across the scientific, pre-clinical, and clinical spectrum: from longitudinal studies of engineered tissue constructs, to tracking disease progression in animal models, to expanding the ability to diagnose and develop treatments for diseases without the need for invasive medical procedures.
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- 2021
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15. Variable frequency response testbed to validate protective relays up to 20 kHz✰
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Thomas P. Karnowski and Emilio C. Piesciorovsky
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Frequency response ,business.industry ,Computer science ,020209 energy ,020208 electrical & electronic engineering ,Protective relay ,Electrical engineering ,Energy Engineering and Power Technology ,02 engineering and technology ,Fault (power engineering) ,Overcurrent ,law.invention ,Relay ,law ,Frequency domain ,0202 electrical engineering, electronic engineering, information engineering ,Harmonic ,Islanding ,Electrical and Electronic Engineering ,business - Abstract
Microgrids operate in islanding or utility grid mode. In islanding mode, distributed energy sources with power electronics inverters can generate fault currents over a wide range of frequencies. To gain a better understanding of the nature of these events, it is crucial to measure currents at frequencies of up to 20 kHz at transient states with protective relays. Protective relays at these frequency responses should be tested prior to being installed in microgrids. However, testing at high-frequency currents cannot be done with Relay Test Equipment (RTE) that generate signals up to 50th Harmonic for 60 Hz (3 kHz). In this study, a frequency response method and testbed for high-frequency currents of up to 20.16 kHz was developed and tested. The testbed utilized a RTE and High-Frequency Power Source/ Amplifier. Frequency relay experiments were run at frequencies of up to 1 and 20.16 kHz at a current magnitude of 0.1 and 0.5 A, respectively. The events were collected, and the current magnitude and frequency were plotted at time and frequency domain, respectively. The study of current magnitude and frequencies of up to 20.16 kHz for two overcurrent relays was performed and validated the variable frequency testbed and methodology.
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- 2021
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16. Automated Video Surveillance for the Study of Marine Mammal Behavior and Cognition
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Edwin Hutchins, Christine M. Johnson, and Jeremy Karnowski
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0106 biological sciences ,Communication ,business.industry ,Dolphins ,010604 marine biology & hydrobiology ,Video data ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Cognition ,General Medicine ,Biology ,Unmanned aerial vehicles ,010603 evolutionary biology ,01 natural sciences ,Data science ,Automated detection ,Marine mammal ,lcsh:Zoology ,lcsh:QL1-991 ,business - Abstract
Systems for detecting and tracking social marine mammals, including dolphins, can provide data to help explain their social dynamics, predict their behavior, and measure the impact of human interference. Data collected from video surveillance methods can be consistently and systematically sampled for studies of behavior, and frame-by-frame analyses can uncover insights impossible to observe from real-time, freely occurring natural behavior. Advances in boat-based, aerial, and underwater recording platforms provide opportunities to document the behavior of marine mammals and create massive datasets. The use of human experts to detect, track, identify individuals, and recognize activity in video demands significant time and financial investment. This paper examines automated methods designed to analyze large video corpora containing marine mammals. While research is converging on best solutions for some automated tasks, particularly detection and classification, many research domains are ripe for exploration.
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- 2016
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17. Experiments and Analysis for Measuring Mechanical Motion with Event Cameras
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Parker Mitchell, Thomas P. Karnowski, Kathy W. Hylton, and Blake Van Hoy
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Computer science ,business.industry ,Event (relativity) ,Computer vision ,Artificial intelligence ,business ,Motion (physics) - Published
- 2021
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18. Methods and Comparisons Between Computer Vision and Radar Based Vehicle Location
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Regina K. Ferrell, Thomas P. Karnowski, Deniz Aykac, and Nisha Srinivas
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law ,business.industry ,Computer science ,Computer vision ,Artificial intelligence ,Radar ,business ,law.invention - Published
- 2021
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19. Seeing Through De-Identified Faces in Videos by Humans and a Deep Convolutional Neural Network
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Thomas P. Karnowski, Regina K. Ferrell, David S. Bolme, Asal Baragchizadeh, Alice J. O'Toole, Parisa R. Jesudasen, Kimberley D. Orsten-Hooge, and Carlos D. Castillo
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Ophthalmology ,Computer science ,business.industry ,Pattern recognition ,Artificial intelligence ,business ,Convolutional neural network ,Sensory Systems - Published
- 2020
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20. Speckle decorrelation for cell’s dynamics
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Karol Karnowski, Maciej Wojtkowski, and Paulina Niedzwiedziuk
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Speckle pattern ,Optics ,Materials science ,Optical coherence tomography ,medicine.diagnostic_test ,business.industry ,Dynamics (mechanics) ,Optical coherence microscopy ,medicine ,Speckle decorrelation ,business ,Scanning microscopy - Abstract
Lung cancer cells were measured in scanning Optical Coherence Microscopy setup. Consecutive 2D speckled data was decorrelated to obtain flow information. We observed regions which are more active than others.
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- 2019
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21. Reporting mobile social media use: how survey and experience sampling measures differ
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Daniela Schlütz, Teresa K. Naab, and Veronika Karnowski
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Experience sampling method ,business.industry ,Communication ,Ephemeral key ,05 social sciences ,Internet privacy ,050801 communication & media studies ,0506 political science ,0508 media and communications ,Geography ,Retrospective survey ,050602 political science & public administration ,ddc:300 ,Social media ,business - Abstract
Quantifying the ubiquitous, ephemeral, and highly diverse patterns of mobile social media (MSM) use is a challenge for communication research. Most researchers employ retrospective survey m...
- Published
- 2019
22. Estimating Vehicle Fuel Economy from Overhead Camera Imagery and Application for Traffic Control
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Thomas Karnowski, Ryan Tokola, Sean Oesch, Matthew Eicholtz, Jeff Price, and Tim Gee
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Light source ,Photometric stereo ,business.industry ,Computer science ,Computer vision ,Artificial intelligence ,business - Published
- 2020
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23. 167-PFlops Deep Learning for Electron Microscopy: From Learning Physics to Atomic Manipulation
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Derek C. Rose, Thomas P. Karnowski, Seung-Hwan Lim, Robert M. Patton, Thomas E. Potok, Catherine D. Schuman, Don D. March, Maxim Ziatdinov, Steven R. Young, Travis Johnston, and Sergei V. Kalinin
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Artificial Intelligence System ,Computer science ,business.industry ,Deep learning ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Supercomputer ,Network topology ,01 natural sciences ,Evolutionary computation ,0104 chemical sciences ,Support vector machine ,Computer engineering ,Asynchronous communication ,Artificial intelligence ,0210 nano-technology ,business - Abstract
An artificial intelligence system called MENNDL, which used 25,200 NVIDIA Volta GPUs on Oak Ridge National Laboratory's Summit machine, automatically designed an optimal deep learning network in order to extract structural information from raw atomic-resolution microscopy data. In a few hours, MENNDL creates and evaluates millions of networks using a scalable, parallel, asynchronous genetic algorithm augmented with a support vector machine to automatically find a superior deep learning network topology and hyper-parameter set than a human expert can find in months. For the application of electron microscopy, the system furthers the goal of improving our understanding of the electron-beam-matter interactions and real-time image-based feedback, which enables a huge step beyond human capacity towards nanofabricating materials automatically. MENNDL has been scaled to the 4,200 available nodes of Summit achieving a measured 152.5 PFlops, with an estimated sustained performance of 167 PFlops when the entire machine is available.
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- 2018
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24. Robust reconstruction of local optic axis orientation with fiber-based polarization-sensitive optical coherence tomography
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Qingyun Li, Karol Karnowski, David D. Sampson, Alvenia Cairncross, Martin Villiger, Peter B. Noble, and Alan James
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0301 basic medicine ,Birefringence ,Materials science ,medicine.diagnostic_test ,business.industry ,01 natural sciences ,Atomic and Molecular Physics, and Optics ,Imaging phantom ,Article ,010309 optics ,Optical axis ,03 medical and health sciences ,030104 developmental biology ,Optics ,Optical coherence tomography ,Fiber Bragg grating ,Robustness (computer science) ,0103 physical sciences ,medicine ,business ,Refractive index ,Circular polarization ,Biotechnology - Abstract
It is challenging to recover local optic axis orientation from samples probed with fiber-based polarization-sensitive optical coherence tomography (PS-OCT). In addition to the effect of preceding tissue layers, the transmission through fiber and system elements, and imperfect system alignment, need to be compensated. Here, we present a method to retrieve the required correction factors from measurements with depth-multiplexed PS-OCT, which accurately measures the full Jones matrix. The correction considers both retardation and diattenuation and is applied in the wavenumber domain, preserving the axial resolution of the system. The robustness of the method is validated by measuring a birefringence phantom with a misaligned system. Imaging ex-vivo lamb trachea and human bronchus demonstrates the utility of reconstructing the local optic axis orientation to assess smooth muscle, which is expected to be useful in the assessment of airway smooth muscle thickness in asthma, amongst other fiber-based applications.
- Published
- 2018
25. Deepmod: An Over-the-Air Trainable Machine Modem for Resilient PHY Layer Communications
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Jason M. Vann, Steven R. Young, Adam Anderson, and Thomas P. Karnowski
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050210 logistics & transportation ,Computer science ,business.industry ,Quality of service ,05 social sciences ,Physical layer ,020206 networking & telecommunications ,02 engineering and technology ,Tactical communications ,WiMAX ,0502 economics and business ,0202 electrical engineering, electronic engineering, information engineering ,Wireless ,business ,Communications protocol ,Computer network ,Communication channel - Abstract
Traditional physical layer protocols (e.g. WiFi, WiMax, etc.) are well established and are often optimal in a wide variety of channel conditions including heterogenous links and in tactical communications. Unfortunately, this same optimality encourages ubiquity in wireless communication technology and enhances the potential for catastrophic cyber or physical attacks due to prolific knowledge of underlying physical layers. Any truly resilient communications protocol must be capable of immediate redeployment to meet quality of service (QoS) demands in a wide variety of possible channel media. This work proposes an approach to communications that is contrary to much traditional approaches in that processing blocks are generated real-time and only relevant to the particular channel medium being used. Rather than creating man-made ubiquitous blocks of signal processing, we examine using processing that is immediately expendable once it has been used. This is achieved through software-defined radios, and deep modulation, where system blocks are replaced with machine learning graphs that can be trained, used, and then discarded as needed. Simulation and experimental hardware show how deep modulation can converge to viable communications links, using the same machine intelligence, in vastly different channels.
- Published
- 2018
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- View/download PDF
26. A study of the effects of supine position and fluid intake on normal airway geometry using anatomical optical coherence tomography (Conference Presentation)
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Karol Karnowski, Qingyun Li, Peter Fejes, Anthony Phan, Bryden C. Quirk, David D. Sampson, Fiona M. Wood, and Robert A. McLaughlin
- Subjects
education.field_of_study ,Supine position ,medicine.diagnostic_test ,business.industry ,Laser source ,Population ,Geometry ,respiratory system ,Catheter ,Fluid intake ,Optical coherence tomography ,Mechanism of injury ,medicine ,business ,education ,Airway - Abstract
Airway inhalation injuries are present in up to a third of all major burns patients and are the leading cause of mortality among this population. Understanding the mechanism of injury could minimise oedema (swelling) and airway damage. In this study, we present an anatomical OCT (aOCT) imaging system, based on a 1300-nm wavelength, high-speed, long-range MEMS-VCSEL swept laser source, for real-time volumetric imaging and assessment of inhalation injuries in airways up to 3 cm in diameter. A custom fibre-optic probe with GRIN lens and micro prism is inserted though the nasal passage. Airway cross-sectional images acquired are used to assess airway diameter and lumen area, as well as to visualize the airway in three dimensions. Preliminary scans of healthy human subjects are presented. The effect of the supine position and fluid intake on airway geometry is quantified to better understand how these factors may contribute to the treatment outcomes of burns patients.
- Published
- 2018
- Full Text
- View/download PDF
27. Assessment of airway smooth muscle layers in human airways with single-measurement, polarization-sensitive OCT (Conference Presentation)
- Author
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Alan L. James, David D. Sampson, Qingyun Li, Peter B. Noble, Martin Villiger, and Karol Karnowski
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Polarization sensitive ,business.industry ,Single measurement ,Medicine ,Airway smooth muscle ,Presentation (obstetrics) ,business ,Biomedical engineering - Published
- 2018
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- View/download PDF
28. Detecting Extreme Events in Gridded Climate Data
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Ranga Raju Vatsavai, Bharathkumar Ramachandra, Thomas P. Karnowski, Krishna Karthik Gadiraju, and Dale P. Kaiser
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010504 meteorology & atmospheric sciences ,Meteorology ,Computer science ,business.industry ,spatio-temporal ,Big data ,Geopotential height ,Cold wave ,Climate change ,02 engineering and technology ,01 natural sciences ,anomaly detection ,Scalability ,0202 electrical engineering, electronic engineering, information engineering ,General Earth and Planetary Sciences ,020201 artificial intelligence & image processing ,co-location ,trend analysis ,Scale (map) ,business ,0105 earth and related environmental sciences ,General Environmental Science - Abstract
Detecting and tracking extreme events in gridded climatological data is a challenging problem on several fronts: algorithms, scalability, and I/O. Successful detection of these events will give climate scientists an alternate view of the behavior of different climatological variables, leading to enhanced scientific understanding of the impacts of events such as heat and cold waves, and on a larger scale, the El Niño Southern Oscillation. Recent advances in computing power and research in data sciences enabled us to look at this problem with a different perspective from what was previously possible. In this paper we present our computationally efficient algorithms for anomalous cluster detection on climate change big data. We provide results on detection and tracking of surface temperature and geopotential height anomalies, a trend analysis, and a study of relationships between the variables. We also identify the limitations of our approaches, future directions for research and alternate approaches.
- Published
- 2016
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29. An English scale for measuring mobile phone appropriation: Translation and assessment
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Thilo von Pape, Ioana A. Cionea, Sun Kyong Lee, and Veronika Karnowski
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Linguistics and Language ,Engineering ,Sociology and Political Science ,Scale (ratio) ,Multimedia ,business.industry ,Communication ,computer.software_genre ,Translation (geometry) ,lcsh:P87-96 ,Language and Linguistics ,lcsh:Communication. Mass media ,Appropriation ,Mobile phone ,Human–computer interaction ,business ,computer - Abstract
The mobile phone appropriation (MPA) scale, originally developed in German, was translated into and adapted to English and initially validated through a confirmatory factory analysis (CFA) in this study. First, the theoretical background of the MPA model is briefly introduced, followed by explanations regarding the process of translating the original German scale into English (and its back-translation). English data CFA results are discussed in comparison with the CFA results from the most recent German data. The results indicate that the English MPA scale has promising validity. The addition of measurement items for the usage of web applications in the English and German MPA scales is expected to contribute to ongoing research efforts of comparing mobile phone appropriation patterns with and across different social and cultural groups in English-speaking contexts.
- Published
- 2016
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- View/download PDF
30. Motion correction for passive radiation imaging of small vessels in ship-to-ship inspections
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Klaus P. Ziock, Thomas P. Karnowski, Vincent C. Paquit, Lorenzo Fabris, Dilip R. Patlolla, Chris Bensing Boehnen, Joseph M. Ernst, David Trombino, and Jason P. Hayward
- Subjects
Physics ,Nuclear and High Energy Physics ,Pixel ,010308 nuclear & particles physics ,Orientation (computer vision) ,business.industry ,Machine vision ,010401 analytical chemistry ,ComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISION ,Field of view ,Iterative reconstruction ,Tracking (particle physics) ,01 natural sciences ,0104 chemical sciences ,Optics ,0103 physical sciences ,Computer vision ,Artificial intelligence ,Coded aperture ,Sensitivity (control systems) ,business ,Instrumentation ,ComputingMethodologies_COMPUTERGRAPHICS - Abstract
Passive radiation detection remains one of the most acceptable means of ascertaining the presence of illicit nuclear materials. In maritime applications it is most effective against small to moderately sized vessels, where attenuation in the target vessel is of less concern. Unfortunately, imaging methods that can remove source confusion, localize a source, and avoid other systematic detection issues cannot be easily applied in ship-to-ship inspections because relative motion of the vessels blurs the results over many pixels, significantly reducing system sensitivity. This is particularly true for the smaller watercraft, where passive inspections are most valuable. We have developed a combined gamma-ray, stereo visible-light imaging system that addresses this problem. Data from the stereo imager are used to track the relative location and orientation of the target vessel in the field of view of a coded-aperture gamma-ray imager. Using this information, short-exposure gamma-ray images are projected onto the target vessel using simple tomographic back-projection techniques, revealing the location of any sources within the target. The complex autonomous tracking and image reconstruction system runs in real time on a 48-core workstation that deploys with the system.
- Published
- 2016
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31. Optical Coherence Tomography of the Labial Salivary Glands Reveals Age-Related Differences in Women
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Jarosław Walkowiak, Ireneusz Grulkowski, Maciej Wojtkowski, Karol Karnowski, and Jan Krzysztof Nowak
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Minor Salivary Glands ,medicine.diagnostic_test ,business.industry ,General Neuroscience ,Lower lip ,Tissue sample ,Mean age ,General Medicine ,Anatomy ,Reflectivity ,General Biochemistry, Genetics and Molecular Biology ,Optical coherence tomography ,Age related ,Medicine ,General Pharmacology, Toxicology and Pharmaceutics ,business ,Mouth mucosa - Abstract
The labial minor salivary glands (LSGs) play a role in medical research and practice due to their superficial location and involvement in both systemic and localized diseases. Swept-source optical coherence tomography (OCT) is a noninvasive modality that enables in vivo, micrometer resolution, wide-field three-dimensional imaging in seconds. A purpose-built swept-source OCT instrument was employed to acquire three-dimensional datasets covering the area of 2.43 cm(2) of the mucosa of the lower lip to the depth of 3.4 mm in young (n = 14; mean age ± SD: 27 ± 3 years; body mass index [BMI] 20.4 ± 2.3 kg/m(2) ) and middle-aged women (n = 11; 54 ± 6 years; 25.5 ± 3.2 kg/m(2) ). Glandular tissue reflectivity mode (range 0-255; 86 ± 17 vs. 68 ± 12, p = 0.005), average single LSG area in tissue sample (5.26 ± 2.62 mm(2) vs. 2.87 ± 1.26 mm(2) , p = 0.011), and LSG surface filling factor (0.23 ± 0.13 vs. 0.11 ± 0.10, p = 0.027) had higher values in younger than in middle-aged women. A correlation between BMI and glandular tissue reflectivity mode (Spearman's ρ = -0.60) was found (p = 0.002). The results highlight the potential value of LSGs' OCT morphometry in research regarding ageing.
- Published
- 2015
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32. Local polarization properties of human anterior segment with single-measurement, full-range polarization-sensitive OCT
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Martin Villiger, Qingyun Li, Karol Karnowski, and David D. Sampson
- Subjects
0301 basic medicine ,Physics ,medicine.diagnostic_test ,business.industry ,Quantitative Biology::Tissues and Organs ,Physics::Medical Physics ,Single measurement ,Polarization (waves) ,01 natural sciences ,010309 optics ,03 medical and health sciences ,030104 developmental biology ,Optical imaging ,Optics ,Polarization sensitive ,Optical coherence tomography ,Computer Science::Computer Vision and Pattern Recognition ,0103 physical sciences ,medicine ,business - Abstract
We report single-measurement, full-range imaging of local polarization properties in the human anterior segment in vivo with polarization-sensitive optical coherence tomography (PS-OCT). Off-pivot galvanometer-mirror phase shifting used to extend the system's axial imaging range sufficiently to reconstruct local polarization properties of the anterior segment.
- Published
- 2017
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33. Vehicle Classification and Identification Using Multi-Modal Sensing and Signal Learning
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Mike Kuhn, Ryan Tokola, Jason M. Vann, Brad J Stinson, Ryan A. Kerekes, Michael R. Moore, Thomas P. Karnowski, and Adam Anderson
- Subjects
050210 logistics & transportation ,Electromagnetics ,Computer science ,business.industry ,Machine vision ,05 social sciences ,020206 networking & telecommunications ,Pattern recognition ,02 engineering and technology ,computer.software_genre ,Signal ,Identification (information) ,Modal ,0502 economics and business ,0202 electrical engineering, electronic engineering, information engineering ,Kernel regression ,Data mining ,Artificial intelligence ,business ,computer - Abstract
Vehicle counting, time-of-travel analysis, and other traffic studies frequently require the classification and identification of vehicles in a roadway. Unfortunately, many current technologies for identifying vehicles, such as image-based methods that use cameras and machine vision, are not appropriate for studies that require low-power consumption and low cost. Additionally, privacy issues are becoming a larger concern with the increasing controversy surrounding the public collection of imagery. In this work we evaluate a multi-modal sensing approach to vehicle classification and identification using an ensemble of sensors measurements including electromagnetic emanations and acoustic signatures. A novel kernel regression method is also used for signal learning to classify and identify vehicles without the need of invasive images. Multi-mode sensing, as well as signal learning, is shown to significantly increase the classification rate of specific vehicle classes.
- Published
- 2017
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34. Evaluation of Automated Identity Masking Method (AIM) in Naturalistic Driving Study (NDS)
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Thomas P. Karnowski, Alice J. O'Toole, Asal Baragchizadeh, and David S. Bolme
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Masking (art) ,business.industry ,Computer science ,Facial motion capture ,media_common.quotation_subject ,Speech recognition ,020206 networking & telecommunications ,02 engineering and technology ,Filter (signal processing) ,Facial recognition system ,Action (philosophy) ,020204 information systems ,Face (geometry) ,Perception ,0202 electrical engineering, electronic engineering, information engineering ,Identity (object-oriented programming) ,Computer vision ,Artificial intelligence ,business ,media_common - Abstract
Identity masking methods have been developed in recent years for use in multiple applications aimed at protecting privacy. There is only limited work, however, targeted at evaluating effectiveness of methods–with only a handful of studies testing identity masking effectiveness for human perceivers. Here, we employed human participants to evaluate identity masking algorithms on video data of drivers, which contains subtle movements of the face and head. We evaluated the effectiveness of the “personalized supervised bilinear regression method for Facial Action Transfer (FAT)” de-identification algorithm. We also evaluated an edge-detection filter, as an alternate “fill-in” method when face tracking failed due to abrupt or fast head motions. Our primary goal was to develop methods for humanbased evaluation of the effectiveness of identity masking. To this end, we designed and conducted two experiments to address the effectiveness of masking in preventing recognition and in preserving action perception. 1- How effective is an identity masking algorithm?We conducted a face recognition experiment and employed Signal Detection Theory (SDT) to measure human accuracy and decision bias. The accuracy results show that both masks (FAT mask and edgedetection) are effective, but that neither completely eliminated recognition. However, the decision bias data suggest that both masks altered the participants’ response strategy and made them less likely to affirm identity. 2- How effectively does the algorithm preserve actions? We conducted two experiments on facial behavior annotation. Results showed that masking had a negative effect on annotation accuracy for the majority of actions, with differences across action types. Notably, the FAT mask preserved actions better than the edge-detection mask. To our knowledge, this is the first study to evaluate a deidentification method aimed at preserving facial actions employing human evaluators in a laboratory setting.
- Published
- 2017
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35. Evaluation of changes in birefringence for samples subjected to various stress sources measured with polarization-sensitive OCT
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Karol Karnowski, David D. Sampson, Martin Villiger, and Qingyun Li
- Subjects
Formalism (philosophy of mathematics) ,Optics ,Birefringence ,Polarization sensitive ,Materials science ,Optical coherence tomography ,medicine.diagnostic_test ,business.industry ,Orthogonal polarization spectral imaging ,medicine ,sense organs ,business ,Polarization (waves) - Abstract
Polarization-sensitive OCT (PS-OCT) has proven useful in determining the stress-induced birefringence of non-biological materials, but such utility in biological tissues subjected to stress has not been well studied yet. To study stress-induced birefringence of biological tissues, we use a swept-source PS-OCT system with passively depth-encoded, orthogonal polarization states in the illumination path and polarization-diversity detection and a Mueller formalism in post-processing. We present measurements of stress-induced changes in the birefringence of non-biological and biological samples that provide useful benchmarks in further assessing the utility of this approach.
- Published
- 2017
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- View/download PDF
36. Ex-vivo imaging of blood and lymphatic vessels in conjunctiva using optical coherence tomography
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Peijun Gong, David D. Sampson, Dong An, Dao-Yi Yu, Karol Karnowski, and Paula K. Yu
- Subjects
Pathology ,medicine.medical_specialty ,Conjunctiva ,genetic structures ,medicine.diagnostic_test ,business.industry ,medicine.medical_treatment ,Glaucoma ,medicine.disease ,eye diseases ,Lymphatic system ,medicine.anatomical_structure ,Optical coherence tomography ,In vivo ,Glaucoma surgery ,medicine ,Lymphatic vessel ,sense organs ,business ,Ex vivo - Abstract
Label-free imaging of the blood and lymphatic vessel networks of the conjunctiva of the eye is important in assessing the drainage pathways affected by glaucoma. We utilize the characteristically low signal in optical coherence tomography (OCT) provided by such vessels in ex vivo tissue to characterize their morphology in two and three dimensions. We demonstrate this method on conjunctiva from six porcine eyes, showing the ready visualization of both vessel networks. Such ex vivo characterization is a necessary precursor for future in vivo studies directed towards improving glaucoma surgery.
- Published
- 2017
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- View/download PDF
37. Preliminary results on in-vivo imaging of upper airway inhalation injuries using anatomical optical coherence tomography
- Author
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Peter Fejes, Robert A. McLaughlin, Bryden C. Quirk, Karol Karnowski, Anthony Phan, Fiona M. Wood, Qingyun Lee, and David D. Sampson
- Subjects
medicine.medical_specialty ,medicine.diagnostic_test ,Inhalation ,business.industry ,Real time imaging ,respiratory system ,Catheter ,Optical coherence tomography ,Inhalation injury ,medicine ,Quantitative assessment ,Radiology ,Airway ,business ,Preclinical imaging - Abstract
Quantitative assessment of upper airway geometry using optical coherence tomography in burns patients could provide physicians with the information needed to make critical decisions. We have developed a high speed catheter based OCT system capable of real time imaging in airways up to 3cm in diameter. Preliminary scans of inhalation injured airways are presented to demonstrate the feasibility of aOCT as a diagnostic tool for assessing burns patients.
- Published
- 2017
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- View/download PDF
38. Local birefringence of the anterior segment of the human eye in a single capture with a full range polarisation-sensitive optical coherence tomography
- Author
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David D. Sampson, Qingyun Li, Martin Villiger, and Karol Karnowski
- Subjects
Materials science ,Birefringence ,medicine.diagnostic_test ,business.industry ,Galvanometer ,Polarization (waves) ,Wavelength ,symbols.namesake ,medicine.anatomical_structure ,Optics ,Optical coherence tomography ,medicine ,symbols ,Human eye ,Mueller calculus ,business - Abstract
A fibre-based full-range polarisation-sensitive optical coherence tomography system is developed to enable complete capture of the structural and birefringence properties of the anterior segment of the human eye in a single acquisition. The system uses a wavelength swept source centered at 1.3 μm, passively depth-encoded, orthogonal polarisation states in the illumination path and polarisation-diversity detection. Off-pivot galvanometer scanning is used to extend the imaging range and compensate for sensitivity drop-off. A Mueller matrix-based method is used to analyse data. We demonstrate the performance of the system and discuss issues relating to its optimisation.
- Published
- 2017
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39. Investigation of stress-induced birefringence of tissue determined with polarisation sensitive optical coherence tomography (Conference Presentation)
- Author
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Martin Villiger, David D. Sampson, Qingyun Li, and Karol Karnowski
- Subjects
Photoelasticity ,Materials science ,Birefringence ,Backscatter ,medicine.diagnostic_test ,business.industry ,Scattering ,Isotropy ,Polarization (waves) ,law.invention ,Lens (optics) ,Optics ,Optical coherence tomography ,law ,medicine ,business - Abstract
Polarisation sensitive optical coherence tomography (PS-OCT) offers additional intrinsic contrast to probe differences between healthy tissue and cancer that are often barely visible due to limited scattering contrast in an OCT image. PS-OCT reconstructs tissue birefringence from phase-sensitive measurements of orthogonal polarisation components of backscattering. In material science, polarisation has been used to study stress distribution, including the birefringence induced by stress in an otherwise isotropic material. Similar effects in biological tissues have not been well studied yet; however, may have application to tissues subjected to stress, e.g., tendons, muscles, lens, cornea or airway smooth muscle (ASM). The objective of this work is to explore stress-induced birefringence in tissue. We employ an advanced swept source-based PS-OCT system capable of measurement of tissue local polarisation properties. The sample in both cases is illuminated with orthogonal, passively depth-encoded polarisation states. Light returning from the tissue is detected via a polarisation-diversity detection module and a Mueller formalism is used to reconstruct polarisation properties (including retardation, diattenuation, and depolarisation) of the tissue. In this study, we demonstrate the measurement of stress-induced birefringence in phantoms and in soft tissues with polarisation sensitive optical coherence tomography.
- Published
- 2017
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40. Ex vivo and in vivo label-free imaging of lymphatic vessels using OCT lymphangiography (Conference Presentation)
- Author
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Shaghayegh Es'haghian, Fiona M. Wood, Suzanne Rea, David D. Sampson, Peijun Gong, Dao-Yi Yu, Karol Karnowski, and Robert A. McLaughlin
- Subjects
medicine.medical_specialty ,genetic structures ,medicine.diagnostic_test ,business.industry ,Confocal ,Glaucoma ,medicine.disease ,eye diseases ,Lymphatic system ,medicine.anatomical_structure ,Optical coherence tomography ,In vivo ,medicine ,Lymphatic vessel ,Medical physics ,sense organs ,business ,Ex vivo ,Burn scar ,Biomedical engineering - Abstract
We have been developing an automated method to image lymphatic vessels both ex vivo and in vivo with optical coherence tomography (OCT), using their optical transparency. Our method compensates for the OCT signal attenuation for each A-scan in combination with the correction of the confocal function and sensitivity fall-off, enabling reliable thresholding of lymphatic vessels from the OCT scans. Morphological image processing with a segment-joining algorithm is also incorporated into the method to mitigate partial-volume artifacts, which are particularly evident with small lymphatic vessels. Our method is demonstrated for two different clinical application goals: the monitoring of conjunctival lymphatics for surgical guidance and assessment of glaucoma treatment; and the longitudinal monitoring of human burn scars undergoing laser ablation treatment. We present examples of OCT lymphangiography ex vivo on porcine conjunctivas and in vivo on human burn scars, showing the visualization of the lymphatic vessel network and their longitudinal changes due to treatment.
- Published
- 2017
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- View/download PDF
41. An educational intervention to improve knowledge about prevention against occupational asthma and allergies using targeted maximum likelihood estimation
- Author
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Swaantje Barth, Constanze Rossmann, Veronika Karnowski, Daloha Rodríguez-Molina, Katja Radon, and Ronald Herrera
- Subjects
Adult ,Male ,medicine.medical_specialty ,Adolescent ,Average treatment effect ,media_common.quotation_subject ,medicine.medical_treatment ,03 medical and health sciences ,0302 clinical medicine ,Hygiene ,Germany ,Surveys and Questionnaires ,Intervention (counseling) ,Hypersensitivity ,Humans ,Medicine ,causal effect ,030212 general & internal medicine ,Asthma, Occupational ,Personal protective equipment ,Occupational Health ,media_common ,Asthma ,Likelihood Functions ,Farmers ,Rehabilitation ,business.industry ,occupational asthma and allergies ,Public Health, Environmental and Occupational Health ,medicine.disease ,030210 environmental & occupational health ,Confidence interval ,Occupational Diseases ,Family medicine ,educational intervention ,preventive measures ,Female ,business ,targeted maximum likelihood estimation ,Occupational asthma - Abstract
Background. Occupational asthma and allergies are potentially preventable diseases affecting 5-15% of the working population. However, the use of preventive measures is often low. The aim of this study was to estimate the average treatment effect of an educational intervention designed to improve the knowledge of preventive measures against asthma and allergies in farm apprentices from Bavaria (Southern Germany). Methods. Farm apprentices at Bavarian farm schools were asked to complete a questionnaire evaluating their knowledge about preventive measures against occupational asthma and allergies (use of personal protective equipment, personal and workplace hygiene measures). Eligible apprentices were randomized by school site to either a control or an intervention group. The intervention consisted of a short educational video about use of preventive measures. Six months after the intervention, subjects were asked to complete a post-intervention questionnaire. Of the 116 apprentices (70 intervention group, 46 control group) who answered the baseline questionnaire only 47 subjects (41%; 17 intervention group, 30 control group) also completed the follow-up questionnaire. We therefore estimated the causal effect of the intervention using targeted maximum likelihood estimation. Models were controlled for potential confounders. Results. Based on the targeted maximum likelihood estimation, the intervention would have increased the proportion of correct answers on all six preventive measures by 18.4% (95% confidence interval: 7.3% - 29.6%) had all participants received the intervention versus had they all been in the control group. Conclusions. These findings indicate the improvement of knowledge by the educational intervention.
- Published
- 2017
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- View/download PDF
42. Vectorial birefringence imaging by optical coherence microscopy for assessing fibrillar microstructures in the cornea and limbus
- Author
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Peter B. Noble, Barry Cense, David D. Sampson, Martin Villiger, Gavrielle R. Untracht, Karol Karnowski, and Qingyun Li
- Subjects
0303 health sciences ,Materials science ,Birefringence ,medicine.diagnostic_test ,business.industry ,Microstructure ,01 natural sciences ,Article ,eye diseases ,Atomic and Molecular Physics, and Optics ,010309 optics ,Optical axis ,03 medical and health sciences ,medicine.anatomical_structure ,Optics ,Optical coherence tomography ,Cornea ,0103 physical sciences ,medicine ,Lamellar structure ,Depth of field ,business ,Image resolution ,030304 developmental biology ,Biotechnology - Abstract
The organization of fibrillar tissue on the micrometer scale carries direct implications for health and disease but remains difficult to assess in vivo. Polarization-sensitive optical coherence tomography measures birefringence, which relates to the microscopic arrangement of fibrillar tissue components. Here, we demonstrate a critical improvement in leveraging this contrast mechanism by employing the improved spatial resolution of focus-extended optical coherence microscopy (1.4 µm axially in air and 1.6 µm laterally, over more than 70 µm depth of field). Vectorial birefringence imaging of sheep cornea ex vivo reveals its lamellar organization into thin sections with distinct local optic axis orientations, paving the way to resolving similar features in vivo.
- Published
- 2020
- Full Text
- View/download PDF
43. Acoustic sequences in non-human animals: a tutorial review and prospectus
- Author
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Alex K. Piel, Edgar E. Vallejo, Gerald G. Carter, Laurance R. Doyle, Laela S. Sayigh, Melissa Hughes, Jeremy Karnowski, Mark A. Bee, Stacy L. DeRuiter, Todd M. Freeberg, Julia Hyland Bruno, Charles T. Taylor, Morgan L. Gustison, Chenghui Ju, Cristiane Cäsar, Daniel T. Blumstein, Eduardo Mercado, Chloé Huetz, Çağlar Akçay, Yan Cao, Peter M. Narins, Bernard Lohr, Gregory A. Backus, Yu Shiu, Brenda McCowan, Michael T. Johnson, Roberta Salmi, Dezhe Z. Jin, Marie A. Roch, Michael H. Coen, Ramon Ferrer-i-Cancho, Heidi E. Harley, Amiyaal Ilany, Veronica Zamora-Gutierrez, Sara Waller, Megan G. Rice, Marta B. Manser, Shimon Edelman, Kirsten M. Bohn, Kazutoshi Sasahara, Arik Kershenbaum, and Ellen C. Garland
- Subjects
0106 biological sciences ,Engineering ,Vocal communication ,business.industry ,05 social sciences ,Homeland security ,Library science ,010603 evolutionary biology ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Research council ,Prospectus ,0501 psychology and cognitive sciences ,Christian ministry ,050102 behavioral science & comparative psychology ,General Agricultural and Biological Sciences ,business ,Naval research - Abstract
This review was developed at an investigative workshop, “Analyzing Animal Vocal Communication Sequences” that took place on October 21–23 2013 in Knoxville, Tennessee, sponsored by the National Institute for Mathematical and Biological Synthesis (NIMBioS). NIMBioS is an Institute sponsored by the National Science Foundation, the U.S. Department of Homeland Security, and the U.S. Department of Agriculture through NSF Awards #EF-0832858 and #DBI-1300426, with additional support from The University of Tennessee, Knoxville. In addition to the authors, Vincent Janik participated in the workshop. D.T.B.’s research is currently supported by NSF DEB-1119660. M.A.B.’s research is currently supported by NSF IOS-0842759 and NIH R01DC009582. M.A.R.’s research is supported by ONR N0001411IP20086 and NOPP (ONR/BOEM) N00014-11-1-0697. S.L.DeR.’s research is supported by the U.S. Office of Naval Research. R.F.-i-C.’s research was supported by the grant BASMATI (TIN2011-27479-C04-03) from the Spanish Ministry of Science and Innovation. E.C.G.’s research is currently supported by a National Research Council postdoctoral fellowship. E.E.V.’s research is supported by CONACYT, Mexico, award number I010/214/2012.
- Published
- 2014
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44. When lifestyle becomes behavior: A closer look at the situational context of mobile communication
- Author
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Veronika Karnowski and Olaf Jandura
- Subjects
Relation (database) ,Computer Networks and Communications ,Computer science ,business.industry ,Mobile computing ,Mobile Web ,Mobile business development ,World Wide Web ,Human–computer interaction ,Mobile search ,Mobile telephony ,Electrical and Electronic Engineering ,business ,Affordance ,Mobile device - Abstract
The web is going mobile, and the scope of mobile communication is widening tremendously, thus paving the way for a wide array of new forms of mobile device use. However, not every user is necessarily all the time taking advantage of the expanded affordances of mobile devices. Texting and phoning are still the predominant services in mobile communication. Previous research has argued that different styles of mobile communication are related to different user lifestyles. Thus, a remapping and matching of the landscape of mobile communication in relation to user lifestyles seems necessary. In this paper, we take one step back and first consider the instances in which lifestyles become behavior; i.e. actual usage situations of mobile communication. We outline three empirically deduced types of mobile communication usage situations, as well as three types of mobile web usage situations, to shed light on the instant at which lifestyle becomes behavior; i.e. at which specific usage situations of mobile communication actually occur.
- Published
- 2014
- Full Text
- View/download PDF
45. Evolving Mobile Media: Uses and Conceptualizations of the Mobile Internet
- Author
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Veronika Karnowski, Lee Humphreys, and Thilo von Pape
- Subjects
Computer Networks and Communications ,business.industry ,Computer science ,05 social sciences ,Internet privacy ,050801 communication & media studies ,Mobile Web ,Mobile business development ,Technological convergence ,Computer Science Applications ,World Wide Web ,0508 media and communications ,Mobile media ,Mobile phone ,0502 economics and business ,Mobile search ,050211 marketing ,The Internet ,business ,Mobile device - Abstract
Technological convergence has led to the ability to access the internet from a variety of mobile devices. Drawing on the Mobile Phone Appropriation Model (Wirth, von Pape & Karnowski, 2008), we sought to understand how people conceptualize and use the mobile internet by conducting semistructured interviews with 21 mobile internet users, half American and half German in order to explore cross-cultural differences. Findings suggest little cross-cultural difference in use and understanding of the mobile Internet. Users do not perceive the act of “going online” as a significant step, even if it is on a mobile device. They do, however, distinguish between different ways of consuming information online (extractive and immersive), relating them to different situations and devices.
- Published
- 2013
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46. Evolving Deep Networks Using HPC
- Author
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Thomas E. Potok, Robert M. Patton, Thomas P. Karnowski, Jonathan Miller, Travis Johnston, Derek C. Rose, William T. Heller, Steven R. Young, and Gabriel Perdue
- Subjects
0301 basic medicine ,Hyperparameter ,Basis (linear algebra) ,Process (engineering) ,Computer science ,business.industry ,Scale (chemistry) ,Deep learning ,Evolutionary algorithm ,02 engineering and technology ,Supercomputer ,Machine learning ,computer.software_genre ,03 medical and health sciences ,030104 developmental biology ,Hyperparameter optimization ,0202 electrical engineering, electronic engineering, information engineering ,020201 artificial intelligence & image processing ,Artificial intelligence ,Data mining ,business ,computer - Abstract
While a large number of deep learning networks have been studied and published that produce outstanding results on natural image datasets, these datasets only make up a fraction of those to which deep learning can be applied. These datasets include text data, audio data, and arrays of sensors that have very different characteristics than natural images. As these "best" networks for natural images have been largely discovered through experimentation and cannot be proven optimal on some theoretical basis, there is no reason to believe that they are the optimal network for these drastically different datasets. Hyperparameter search is thus often a very important process when applying deep learning to a new problem. In this work we present an evolutionary approach to searching the possible space of network hyperparameters and construction that can scale to 18, 000 nodes. This approach is applied to datasets of varying types and characteristics where we demonstrate the ability to rapidly find best hyperparameters in order to enable practitioners to quickly iterate between idea and result.
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- 2017
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47. Final Report: Non-Visible, Automated Target Acquisition and Tracking
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Lorenzo Fabris, James K. Goddard, D. Hornback, Thomas P. Karnowski, Klaus-Peter Ziock, and Jason Newby
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Engineering ,business.industry ,Computer vision ,Artificial intelligence ,Tracking (particle physics) ,business ,Computer security ,computer.software_genre ,Target acquisition ,computer - Published
- 2016
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48. Non-contact investigation of the corneal biomechanics with air-puff swept source optical coherence tomography
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Ewa Maczynska, Ireneusz Grulkowski, Maciej Wojtkowski, Karol Karnowski, and Bartlomiej J. Kaluzny
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Intraocular pressure ,Materials science ,genetic structures ,medicine.diagnostic_test ,business.industry ,Pulse (signal processing) ,Biomechanics ,Air puff ,01 natural sciences ,eye diseases ,010309 optics ,03 medical and health sciences ,0302 clinical medicine ,medicine.anatomical_structure ,Optics ,stomatognathic system ,Optical coherence tomography ,Corneal edema ,Cornea ,0103 physical sciences ,030221 ophthalmology & optometry ,medicine ,sense organs ,business ,Contact Investigation - Abstract
In this paper, we use swept source optical coherence tomography combined with air-puff module (air-puff SS-OCT) to investigate the properties of the cornea. During OCT measurement the cornea was stimulated by short, air pulse, and corneal response was recorded. In this preliminary study, the air-puff SS-OCT instrument was applied to measure behavior of the porcine corneas under varied, well-controlled intraocular pressure conditions. Additionally, the biomechanical response of the corneal tissue before, during and after crosslinking procedure (CXL) was assessed. Air-puff swept source OCT is a promising tool to extract information about corneal behavior as well as to monitor and assess the effect of CXL.
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- 2016
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49. The impact of perioperative β blocker use on patient outcomes after primary cytoreductive surgery in high-grade epithelial ovarian carcinoma
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Laurel W. Rice, Elizabeth L. Dickson, Amy Mc Nally, Cassandra Albertin, Cassandra Niemi, Shitanshu Uppal, Mian M.K. Shahzad, Ahmed Al-Niaimi, Sandeep Saha, Ryan J. Spencer, and Jennifer Karnowski
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0301 basic medicine ,medicine.medical_specialty ,medicine.drug_class ,Population ,Adrenergic beta-Antagonists ,Urology ,Comorbidity ,Carcinoma, Ovarian Epithelial ,Disease-Free Survival ,Perioperative Care ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Carcinoma ,Humans ,Neoplasms, Glandular and Epithelial ,education ,Beta blocker ,Survival rate ,Aged ,Proportional Hazards Models ,Retrospective Studies ,Ovarian Neoplasms ,education.field_of_study ,Proportional hazards model ,business.industry ,Obstetrics and Gynecology ,Retrospective cohort study ,Perioperative ,Cytoreduction Surgical Procedures ,Middle Aged ,medicine.disease ,Surgery ,Survival Rate ,030104 developmental biology ,Treatment Outcome ,Oncology ,030220 oncology & carcinogenesis ,Case-Control Studies ,Hypertension ,Multivariate Analysis ,Female ,Neoplasm Grading ,Ovarian cancer ,business ,Neoplasms, Cystic, Mucinous, and Serous ,Carcinoma, Endometrioid ,Adenocarcinoma, Clear Cell - Abstract
Objective To quantify the impact of perioperative β blocker use on survival after primary cytoreductive surgery for epithelial ovarian cancer. Methods We conducted a multi-center retrospective study of all women who underwent primary cytoreductive surgery for ovarian cancer (2000 − 2010). One institution had routinely used perioperative β blockers for patients “at risk” for coronary events. The other institution did not routinely use perioperative β blockers. Demographic, operative, and follow up data were collected. Cox proportional hazards models were used to assess the effect of β blockers on progression-free interval (PFI) as well as overall survival (OS). Results Out of 185 eligible patients, 70 received β blockers and 115 underwent cytoreductive surgery without perioperative β blockers. Both groups were similar in demographics. A history of hypertension was present more often in the β blocker group compared to the group that did not receive β blockers (22% and 6%, p = 0.002). PFI in β blocker group was greater at 18.2 vs. 15.8 months (p = 0.66). The OS in the β blocker group was significantly higher at 44.2 vs. 39.3 months (p = 0.01). In multivariate analysis, perioperative β blocker use was associated with significant improvement in OS (HR 0.68 (0.46–0.99); p = 0.046). Conclusion Our study showed an association between perioperative β blocker use and longer overall survival in patients undergoing primary ovarian cancer cytoreductive surgery. A prospective randomized clinical trial in this population would further validate these results.
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- 2016
50. Compression optical coherence elastography for improved diagnosis of disease (Conference Presentation)
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Philip Wijesinghe, Arash Arabshahi, Karol Karnowski, Brendan F. Kennedy, Wes M. Allen, Andrea Curatolo, David D. Sampson, Luke Frewer, Shaghayegh Es'haghian, and Lixin Chin
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Mechanical load ,medicine.diagnostic_test ,business.industry ,Acoustics ,Stiffness ,Elasticity (physics) ,Compression (physics) ,Viscoelasticity ,Displacement (vector) ,Optics ,Optical coherence tomography ,medicine ,Elastography ,medicine.symptom ,business - Abstract
Optical coherence elastography (OCE) is emerging as a potentially useful tool in the identification of a number of diseases. In our group, we are developing OCE techniques based on compressive loading. Typically, these techniques employ a quasi-static mechanical load introduced by uniaxially compressing a sample with a rigid plate. The resulting deformation of the sample is measured using phase-sensitive detection and the local axial strain is estimated from the slope of displacement over a finite depth in the sample, providing qualitative mechanical contrast. In this talk, an overview of our work will be given and some of the outstanding challenges described. Our group’s work in OCE can broadly be divided into four streams, each of which will be described in detail in the talk: system development; techniques; quantification; and applications. • System development: The phase-sensitive OCE method we have developed will be described, as well as a high resolution optical coherence microscopy-based elastography system suitable for imaging cellular-scale mechanical properties. • Techniques: In addition to presenting techniques to estimate strain, our approaches to imaging tissue viscoelasticity and nonlinearity will be described. A technique to segment elastograms based on strain heterogeneity will be presented. • Quantification: Methods under development to quantify tissue stiffness in compression OCE will be described. This work is enabled by optical palpation and solutions to the forward and inverse elasticity problems. • Applications: Three applications areas will be described: intraoperative assessment of tumour margins, mapping stiffness in tumour biology and assessing the stiffness of cardiovascular tissue in an animal model.
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- 2016
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