2,369 research outputs found

    Characterization of Photoacoustic Flow Cytometry Signals

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    Photoacoustic flow cytometry has been utilized to clinically determine the presence of melanoma circulating tumor cells (CTCs). Further investigation was conducted into the morphology of detection signals and how they could be manipulated to allow for further classification. Novel features were extracted from waveforms that appear to have strong classification ability. Neural networks were also used to determine classification potential and the creation of feature mapping for future unsupervised classification. Detections were expanded from single waves to a time dependent multiwave event. Waveforms were also determined to be of non-parametric distribution, allowing for classification by neural network but not allowing for reduction into feature maps with techniques used in the study

    The Pan-STARRS Moving Object Processing System

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    We describe the Pan-STARRS Moving Object Processing System (MOPS), a modern software package that produces automatic asteroid discoveries and identifications from catalogs of transient detections from next-generation astronomical survey telescopes. MOPS achieves > 99.5% efficiency in producing orbits from a synthetic but realistic population of asteroids whose measurements were simulated for a Pan-STARRS4-class telescope. Additionally, using a non-physical grid population, we demonstrate that MOPS can detect populations of currently unknown objects such as interstellar asteroids. MOPS has been adapted successfully to the prototype Pan-STARRS1 telescope despite differences in expected false detection rates, fill-factor loss and relatively sparse observing cadence compared to a hypothetical Pan-STARRS4 telescope and survey. MOPS remains >99.5% efficient at detecting objects on a single night but drops to 80% efficiency at producing orbits for objects detected on multiple nights. This loss is primarily due to configurable MOPS processing limits that are not yet tuned for the Pan-STARRS1 mission. The core MOPS software package is the product of more than 15 person-years of software development and incorporates countless additional years of effort in third-party software to perform lower-level functions such as spatial searching or orbit determination. We describe the high-level design of MOPS and essential subcomponents, the suitability of MOPS for other survey programs, and suggest a road map for future MOPS development.Comment: 57 Pages, 26 Figures, 13 Table

    A micropower centroiding vision processor

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    Index to 1981 NASA Tech Briefs, volume 6, numbers 1-4

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    Short announcements of new technology derived from the R&D activities of NASA are presented. These briefs emphasize information considered likely to be transferrable across industrial, regional, or disciplinary lines and are issued to encourage commercial application. This index for 1981 Tech Briefs contains abstracts and four indexes: subject, personal author, originating center, and Tech Brief Number. The following areas are covered: electronic components and circuits, electronic systems, physical sciences, materials, life sciences, mechanics, machinery, fabrication technology, and mathematics and information sciences

    Video based vehicle detection for advance warning Intelligent Transportation System

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    Video based vehicle detection and surveillance technologies are an integral part of Intelligent Transportation System (ITS), due to its non-intrusiveness and capability or capturing global and specific vehicle behavior data. The initial goal of this thesis is to develop an efficient advance warning ITS system for detection of congestion at work zones and special events based on video detection. The goals accomplished by this thesis are: (1) successfully developed the advance warning ITS system using off-the-shelf components and, (2) Develop and evaluate an improved vehicle detection and tracking algorithm. The advance warning ITS system developed includes many off-the-shelf equipments like Autoscope (video based vehicle detector), Digital Video Recorders, RF transceivers, high gain Yagi antennas, variable message signs and interface processors. The video based detection system used requires calibration and fine tuning of configuration parameters for accurate results. Therefore, an in-house video based vehicle detection system was developed using the Corner Harris algorithm to eliminate the need of complex calibration and contrasts modifications. The algorithm was implemented using OpenCV library on a Arcom\u27s Olympus Windows XP Embedded development kit running WinXPE operating system. The algorithm performance is for accuracy in vehicle speed and count is evaluated. The performance of the proposed algorithm is equivalent or better to the Autoscope system without any modifications to calibration and lamination adjustments

    Grids and the Virtual Observatory

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    We consider several projects from astronomy that benefit from the Grid paradigm and associated technology, many of which involve either massive datasets or the federation of multiple datasets. We cover image computation (mosaicking, multi-wavelength images, and synoptic surveys); database computation (representation through XML, data mining, and visualization); and semantic interoperability (publishing, ontologies, directories, and service descriptions)

    Quantifying Human Impacts on River Bar Morphology Using Digital Photogrammetry

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    Historically, the study of fluvial geomorphology has been dominated by the field method of surveying using a level and surveying rod. Beginning in the 1980s, the use of ground based and aerial LiDAR increased in popularity as a surveying method. However, LIDAR is expensive and requires significant training to operate. In recent years there has been an increase in the applicability of digital photogrammetry in the field of fluvial geomorphology. Lower costs, streamlined training and an increased accuracy all make digital photogrammetry a promising tool for the field geomorphologist. A study of the morphologic changes of four river bars on the Browns Canyon section of the Arkansas River, Colorado is used to explore the potential of digital photogrammetry by attempting to quantify the impacts of recreation river users on bar morphology. By creating high resolution digital elevation models (DEMs) at time intervals from 24 hours to several days, DEMs of difference (DoDs) were created and analyzed using the open-source 3D data processing software CloudCompare. DoDs were correlated with historical, daily commercial river user data to derive a relationship. Verification concerning the validity of CloudCompare was done using a simple experiment simulating erosion and deposition of a known volume of material

    Numerical and experimental analysis on microbubble generation and multiphase mixing in novel microfluidic devices

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    In this study, a novel K-junction microfluidic junction and a conventional cross-junction were investigated numerically and experimentally for microbubble generation and multiple fluids mixing. In the K-junction, liquid solutions were injected into the junction via three liquid inlet channels, along with inert nitrogen gas supplied via the gas inlet channel, to periodically generate microbubbles in a controlled manner at the outlet channel. Numerical simulations based on Finite Volume method and Volume of Fluid (VOF) technique and experiments of both the K-junction and the cross-junction were conducted. The effect of parameters such as contact angle, surface tension, viscosity, gas pressure and gas-liquid flow ratios on the microbubble size distribution was investigated. The process of microbubble generation, obtained through high speed camera imaging and the numerical simulation, has shown good agreement in both junctions as well as the influence of viscosity and gas-liquid flow ratios for the K-junction and cross-junction. It was indicated that parameters like solution viscosities, gas-to-liquid flow ratios, gas inlet pressure, and their combination have a significant influence on the microbubble diameter, which was found to be in the range of 70-240 µm when using micro capillaries of 100 µm inner diameter. The multiple fluids mixing study was investigated by using two or three different polymer solutions for the cross-junction and the K-junction respectively in simulations and experiments. It can be seen that the mixing process obtained from simulations agrees well with experimental results and chaotic mixing was found in the mixing area of the K-junction, with higher mixing efficiency than the cross junction. Fluorescent images of microbubbles generated by using polymer solutions with dyes inside have shown the devices’ potential of encapsulating fluorescent dyes and polymers on the shell of bubbles and could be adopted as a method to encapsulate active pharmaceutical ingredients for potential applications in drug delivery

    Advancements and Breakthroughs in Ultrasound Imaging

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    Ultrasonic imaging is a powerful diagnostic tool available to medical practitioners, engineers and researchers today. Due to the relative safety, and the non-invasive nature, ultrasonic imaging has become one of the most rapidly advancing technologies. These rapid advances are directly related to the parallel advancements in electronics, computing, and transducer technology together with sophisticated signal processing techniques. This book focuses on state of the art developments in ultrasonic imaging applications and underlying technologies presented by leading practitioners and researchers from many parts of the world
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