Exploiting coherence in time-varying voxel data

We encode time-varying voxel data for efficient storage and streaming. We store the equivalent of a separate sparse voxel octree for each frame, but utilize both spatial and temporal coherence to reduce the amount of memory needed. We represent the time-varying voxel data in a single directed acyclic graph with one root per time step. In this graph, we avoid storing identical regions by keeping one unique instance and pointing to that from several parents. We further reduce the memory consumption of the graph by minimizing the number of bits per pointer and encoding the result into a dense bitstream

Characterizing larval swordfish habitat in the western tropical North Atlantic

Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Fisheries Oceanography, 27 (2018): 246-258, doi:10.1111/fog.12249.Swordfish Xiphias gladius (Linnaeus, 1758) are a circumglobal pelagic fish targeted by multiple lucrative fisheries. Determining the distribution of swordfish larvae is important for indicating reproductive activity and understanding the early life history of swordfish. We identify and characterize larval swordfish distributions during peak swordfish spawning throughout the Gulf of Mexico and western Caribbean Sea with generalized additive models (GAMs) using catches of swordfish larvae during ichthyoplankton surveys in April and May of 2010, 2011, and 2012. The best fit GAM, as determined by stepwise, backward Akaike Information Criterion selection, included both physiochemical (temperature at 5 m, sea surface height anomaly (SSHA), eddy kinetic energy (EKE)), temporal (lunar illumination, hour of sampling) and spatial (location) variables, while near-surface chlorophyll a concentration residuals remained as a random effect. The highest probability of larval swordfish catch occurred at sub-surface temperatures, SSHA, and EKE values indicative of boundary currents. Standard lengths of larvae were larger further downstream in the boundary currents, despite high variability in length with location due to multiple spawning locations of swordfish near these currents. Probability of larval swordfish catch also peaked during the crescent and gibbous moons, indicating a lunar periodicity to swordfish spawning. These results suggest that swordfish may spawn during select moon phases near boundary currents that transport their larvae to larval and juvenile habitat including the northern Gulf of Mexico and coastal waters of the southeast United States.NASA Grant Numbers: NNX11AP76G, NNX08AL06

The velocity distribution of nearby stars from Hipparcos data I. The significance of the moving groups

We present a three-dimensional reconstruction of the velocity distribution of nearby stars (<~ 100 pc) using a maximum likelihood density estimation technique applied to the two-dimensional tangential velocities of stars. The underlying distribution is modeled as a mixture of Gaussian components. The algorithm reconstructs the error-deconvolved distribution function, even when the individual stars have unique error and missing-data properties. We apply this technique to the tangential velocity measurements from a kinematically unbiased sample of 11,865 main sequence stars observed by the Hipparcos satellite. We explore various methods for validating the complexity of the resulting velocity distribution function, including criteria based on Bayesian model selection and how accurately our reconstruction predicts the radial velocities of a sample of stars from the Geneva-Copenhagen survey (GCS). Using this very conservative external validation test based on the GCS, we find that there is little evidence for structure in the distribution function beyond the moving groups established prior to the Hipparcos mission. This is in sharp contrast with internal tests performed here and in previous analyses, which point consistently to maximal structure in the velocity distribution. We quantify the information content of the radial velocity measurements and find that the mean amount of new information gained from a radial velocity measurement of a single star is significant. This argues for complementary radial velocity surveys to upcoming astrometric surveys

Neutrophil-induced endothelial barrier dysfunction in acute inflammation : mechanisms and therapeutic strategies

The acute inflammatory response is characterized by recruitment of leukocytes and increased vascular permeability, resulting in the cardinal signs of inflammation; redness, heat, swelling, pain and loss of function. Permeability changes of the vascular wall are important in functional immune responses and host defense. On the other hand, derangement of the vascular barrier is a principal cause for plasma leakage and edema formation in severe disease states such as sepsis, substantially accounting for high morbidity and mortality by contributing to organ dysfunction and circulatory failure. Neutrophil granulocytes, a subtype of leukocytes, are first on sight in the acute inflammatory response where they adhere to, and migrate through, a monolayer of endothelial cells that constitute the innermost layer of the vascular wall. Neutrophil-derived proteins, released from activated neutrophils, cause endothelial barrier disruption via partly unknown mechanisms. Since neutrophil activation and degranulation are considered central in the pathogenesis of acute inflammatory disease states, and novel treatment strategies are sought after, this thesis work aimed to further expand our understanding of mechanisms regulating neutrophil-evoked alterations of the endothelial barrier. In paper I, the role of the kallikrein-kinin system (KKS) in neutrophil- induced vascular leakage was investigated. The KKS is a pro-inflammatory protein complex found in plasma that is responsible for formation of bradykinin (BK), a known inducer of vascular hyperpermeability via binding of bradykinin receptors on endothelial cells. In three different in vivo models of acute inflammation in two different species, we found that inhibition of KKS attenuated neutrophil-mediated plasma leakage. Further, in vitro studies with isolated human neutrophils and endothelial cells showed that factors secreted from activated neutrophils caused BK-mediated endothelial barrier disruption, and that neutrophil-derived heparin-binding protein facilitated KKS activation caused by neutrophil granule proteases. In paper II, we investigated the therapeutic potential and mode of action of the heparin derivative sevuparin in neutrophil-mediated vascular leak caused by group A Streptococcus. In vivo and in vitro studies showed that sevuparin attenuated endothelial barrier disruption and lung plasma leakage by neutralizing neutrophil-derived proteins. Affinity chromatography and mass spectrometry were utilized to identify proteins targeted by sevuparin, confirming the previously established disruptive role of several neutrophil- derived proteins on endothelial barrier function. In paper III, we tested the hypothesis that platelet-derived polyphosphates (polyP) activate neutrophils, and investigated polyP as a potential therapeutic target in acute inflammation. During inflammation, interaction of activated platelets with neutrophils results in neutrophil activation. Also, platelets are known to release polyP that have been attributed roles in both inflammation and coagulation. We found in vitro that polyP induced neutrophil degranulation and in vivo that systemic administration of polyP caused lung plasma leakage in a neutrophil-dependent manner. Furthermore, inhibition of polyP decreased lung plasma leakage in a mouse model of acute systemic inflammation induced by group A Streptococcus. In paper IV, we set out to investigate the effect of phenylbutyrate (PBA), a short-chain fatty acid suggested to have immunomodulatory properties, on the inflammatory response in a mouse model of pneumonia with Pseudomonas aeruginosa. PBA treatment altered the kinetics of neutrophil recruitment in lungs in response to P. aeruginosa resulting in enhanced initial mobilization of neutrophils followed by a more rapid decline in cell recruitment compared to no treatment. Coincident with the decline in cell recruitment, lung edema and protein leakage was reduced. In vitro, PBA was found to promote release of neutrophil chemotactic factors from lung epithelium. In conclusion, this thesis work provides new insights into mechanisms regulating endothelial barrier function in neutrophilic inflammation and suggests potential therapeutic strategies

Towards accessible content creation of real world objects for virtual environments

3D reconstruction is the general problem of creating 3D models from real world objects. In today\u27s movie and games industry,there is an increasing demand for using real world content as assets in production. In general, however, 3D reconstruction is achallenging problem, and current techniques only allow for production-ready results given a combination of expensive equipment andspecific expertise.This thesis is a collection of three papers that address various aspects of this general problem of 3D reconstruction,with the aim of lowering the bar for making usable real world content.In Paper I, we address the problem of storing and streaming time varying geometry for e.g.\ free-viewpoint video, whichotherwise has too high bandwidth requirements to be streamed efficiently. We use a memory-efficient structure based on compressedvoxels to store the data, in which we can send only incremental updates to the geometry in each frame.In Paper II, we implement an end-to-end real-time pipeline for free-viewpoint video communication.The pipeline uses a set of ordinary webcams as input and do all processing on a single desktop computer. Even with theselimitations, we show that we can produce free-viewpoint video with agreeable quality in real-time.Paper III addresses the problem of accessible and accurate modeling of static real-world objects.Given a set of calibrated input images, we have developed an interactive tool that makes 3D reconstruction with multi-view stereo moreaccessible. This interactive reconstruction has several advantages over automatic 3D scanning, since we obtain correct topology by designas well as information about visibility and foreground segmentation

Influences of Block Play on Academic Learning in Preschool

Preschool classrooms often include free play time during the school day. Many studies have been conducted on the common sociodramatic play center, yet less research has observed the importance of block play. However, the block play center can be used to foster literacy and mathematics skills. Similar to other play centers, block play is a social phenomenon where students can develop language skills and vocabulary. Early math skills are supported as students count, sort, classify, and identify blocks. Students must also use spatial awareness and language to place blocks. Furthermore, preschoolers must problem solve and use logical and creative thinking to strengthen block structures. Finally, blocks are representational in that they serve as symbols. By understanding symbolic representation, students are learning that an object or idea can stand for something else, similar to written words. It is important for preschool teachers to develop a strong block play center where students can participate in sustained block play in order to foster reading literacy and mathematics skills

Global monitoring of fluidized-bed processes by means of microwave cavity resonances

We present an electromagnetic measurement system for monitoring of the effective permittivity in closed metal vessels, which are commonly used in the process industry. The measurement system exploits the process vessel as a microwave cavity resonator and the relative change in its complex resonance frequencies is related to the complex effective permittivity inside the vessel. Also, thermal expansion of the process vessel is taken into account and we compensate for its influence on the resonance frequencies by means of a priori information derived from a set of temperature measurements. The sensitivities, that relate the process state to the measured resonance frequencies, are computed by means of a detailed finite element model. The usefulness of the proposed measurement system is successfully demonstrated for a pharmaceutical fluidized-bed process, where the water and solid contents inside the process vessel is of interest

Tests of Methods that Control Round-Off Error

Methods of controlling round-off error in one-step methods in the numerical solution of ordinary differential equations are compared. A new Algorithm called theoretical cumulative rounding is formulated. Round-off error bounds are obtained for single precision, and theoretical cumulative rounding. Limits of these bounds are obtained as the step length approaches zero. It is shown that the limit of the bound on the round-off error is unbounded for single precision and double precision, is constant for theoretical partial double precision, and is zero for theoretical cumulative rounding. The limits of round-off bounds are not obtainable in actual practice. The round-off error increases for single precision, remains about constant for partial double precision and decreases for cumulative rounding as the step length decreases. Several examples are included. (34 pages

Automatic Test Methods for Image and Video Verification

In this thesis four methods for automatic verification of images and video on mobile platforms are developed. Both the case of recording images and video and the case of viewing images and video on the mobile lcd screen are considered. The first method is used to test the zoom function of the camera. It uses SURF decriptors along with clustering and histograms to determine which of six discrete zoom levels the current frame belongs to. The second method identifies color effects and color anomalies using histograms. The third method determines if the autofocus works correctly by measuring the average length of edges in the image. The fourth method is an artifact detection scheme using a non-reference implementation of the SSIM metric, used in conjunction with a for this purpose specially designed test setup. Together these methods form a tool kit for detecting the mnost common errors to occur in images and video during the development stage of mobile platforms