3,376 research outputs found

    Radar-only ego-motion estimation in difficult settings via graph matching

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    Radar detects stable, long-range objects under variable weather and lighting conditions, making it a reliable and versatile sensor well suited for ego-motion estimation. In this work, we propose a radar-only odometry pipeline that is highly robust to radar artifacts (e.g., speckle noise and false positives) and requires only one input parameter. We demonstrate its ability to adapt across diverse settings, from urban UK to off-road Iceland, achieving a scan matching accuracy of approximately 5.20 cm and 0.0929 deg when using GPS as ground truth (compared to visual odometry's 5.77 cm and 0.1032 deg). We present algorithms for keypoint extraction and data association, framing the latter as a graph matching optimization problem, and provide an in-depth system analysis.Comment: 6 content pages, 1 page of references, 5 figures, 4 tables, 2019 IEEE International Conference on Robotics and Automation (ICRA

    Probably Unknown: Deep Inverse Sensor Modelling In Radar

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    Radar presents a promising alternative to lidar and vision in autonomous vehicle applications, able to detect objects at long range under a variety of weather conditions. However, distinguishing between occupied and free space from raw radar power returns is challenging due to complex interactions between sensor noise and occlusion. To counter this we propose to learn an Inverse Sensor Model (ISM) converting a raw radar scan to a grid map of occupancy probabilities using a deep neural network. Our network is self-supervised using partial occupancy labels generated by lidar, allowing a robot to learn about world occupancy from past experience without human supervision. We evaluate our approach on five hours of data recorded in a dynamic urban environment. By accounting for the scene context of each grid cell our model is able to successfully segment the world into occupied and free space, outperforming standard CFAR filtering approaches. Additionally by incorporating heteroscedastic uncertainty into our model formulation, we are able to quantify the variance in the uncertainty throughout the sensor observation. Through this mechanism we are able to successfully identify regions of space that are likely to be occluded.Comment: 6 full pages, 1 page of reference

    Do Ho Suh

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    Do Ho Suh’s use of fabric has a number of different origins. Most directly, he was looking to create a “suitcase home,” that he could pack up and take with him and erect anywhere in an attempt to live in the presence of the places he had left behind. Fabric is light and packable, and it has an ethereal, translucent quality that hints at the structure’s transience; it is a representation of a memory that still feels like memory

    Through place

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    Through Place is comprised of diverse, sometimes un-idyllic landscapes. Many of the pictures contain a trace--an alteration to the land, a specter of human presence. Yet these marks are pictured inclusively; the scenes are explored with interest and without judgment. They offer a reformulation of the division between the human and the natural, wherein the natural draws the largest circle. The images are made in geographically and culturally diverse places (from the Peruvian Amazon to ski mountains in California). Place becomes replaced by interpretation, fiction: representations that intermingle with our own agency, expectations, and memories

    The Dwarfs Beyond: The Stellar-to-Halo Mass Relation for a New Sample of Intermediate Redshift Low Mass Galaxies

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    A number of recent challenges to the standard Lambda-CDM paradigm relate to discrepancies that arise in comparing the abundance and kinematics of local dwarf galaxies with the predictions of numerical simulations. Such arguments rely heavily on the assumption that the local dwarf and satellite galaxies form a representative distribution in terms of their stellar-to-halo mass ratios. To address this question, we present new, deep spectroscopy using DEIMOS on Keck for 82 low mass (10^7-10^9 solar masses) star-forming galaxies at intermediate redshift (z=0.2-1). For 50 percent of these we are able to determine resolved rotation curves using nebular emission lines and thereby construct the stellar mass Tully-Fisher relation to masses as low as 10^7 solar masses. Using scaling relations determined from weak lensing data, we convert this to a stellar-to-halo mass (SHM) relation for comparison with abundance matching predictions. We find a discrepancy between the propagated predictions from simulations compared to our observations, and suggest possible reasons for this as well as future tests that will be more effective.Comment: 11 pages, 7 figures, submitted to ApJ, comments welcom

    Modelling Clustering of Wireless Sensor Networks with Synchronised Hyperedge Replacement

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    This paper proposes Synchronised Hyperedge Replacement (SHR) as a suitable modelling framework for Wireless Sensor Networks (WSNs). SHR facilitates explicit modelling of WSNs applications environmental conditions (that significantly affect applications performance) while providing a sufficiently high level of abstraction for the specification of the underling coordination mechanisms. Because it is an intractable problem to solve in distributed manner, and distribution is important, we propose a new Nutrient-flow-based Distributed Clustering (NDC) algorithm to be used as a working example. The key contribution of this work is to demonstrate that SHR is sufficiently expressive to describe WSNs algorithms and their behaviour at a suitable level of abstraction to allow onward analysis

    Tyrosine hydroxylase neurons in the male hamster chemosensory pathway contain androgen receptors and are influenced by gonadal hormones

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    Chemosensory and hormonal signals, both of which are essential for mating in the male Syrian hamster, are relayed through a distinct forebrain circuit. Immunocytochemistry for tyrosine hydroxylase, a catecholamine biosynthetic enzyme, previously revealed immunoreactive neurons in the anterior and posterior medial amygdaloid nucleus, one of the nuclei within this pathway. In addition, dopamine-immunoreactive neurons were located in the posterior, but not hte anterior, medial amygdala. In the present study, tyrosine hydroxylase-immunostained neurons were also observed in other areas of the chemosensory pathway, including the posteromedial bed nucleus of the stria terminalis and the posterior, lateral part of the medial preoptic area, while dopamine immunostaining was only seen in the posteromedial bed nucleus of the stria terminalis. The colocalization of tyrosine hydroxylase and androgen receptors was examined in these four tyrosine hydroxylase cell groups by a double immunoperoxidase technique. The percentage of tyrosine hydroxylase-immunolabeled neurons that were also androgen receptor-immunoreactive was highest in the posterior medial amygdaloid nucleus (74%) and the bed nucleus of the stria terminalis (79%). Fewer tyrosine hydroxylase-immunostained neurons in the anterior medial amygdala (33%) and the medial preoptic area (4%) contained androgen receptors. Surprisingly, castration resulted in a significant decrease in the number of tyrosine hydroxylase-immunoreactive neurons only in the anterior medial amygdaloid nucleus, and this effect was transient. Six weeks after castratio, the anterior medial amygdala contained 61% fewer tyrosine hydroxylase-immunolabeled neurons, but 12 weeks after gonadectomy, immunostaining returned to intact values. The number of immunostained neurons in testosterone-replaced, castrated hamsters was not significantly different from that of intact or castrated animals at any time. The results of this study indicate that a substantial number of tyrosine hydroxylase-immunostained neurons in the chemosensory pathway are influenced by androgens; the majority of these neurons in the posterior medial amygdala and the posteromedial bed nucleus of the stria terminalis produce androgen receptors, and tyrosine hydroxylase immunoreactivity is altered by castration in the anterior medial amygdala. © 1993 Wiley-Liss, Inc.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50056/1/903310402_ftp.pd

    Mount Carmel Food Pantry Composting Project

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    Despite best efforts, food pantries do produce food waste. This can be from produce going bad before it can be distributed, personal preferences leading to certain foods not being distributed, or donated food being too close to spoilage, etc. This 21 page report investigates the issue of food waste at the Mount Carmel Area Food Pantry run by the Mount Carmel Area Ministerium and proposes composting as a solution. Composting will reduce the amount of garbage going to the landfill and keep the nutrients in the community by providing compost for home or community gardening, which can be part of a broader food security network. Students produced this report as part of Environmental Studies 411 (ENST 411), a senior capstone course taught by Prof. Andrew Stuhl. Funding to install the demonstration compost systems referenced in the report was provided by the Ekedahl fund through the Bucknell Center for Sustainability and the Environment

    Prodynorphin peptide distribution in the forebrain of the syrian hamster and rat: A comparative study with antisera against dynorphin A, dynorphin B, and the C-terminus of the prodynorphin precursor molecule

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    The neuroanatomical distribution of the prodynorphin precursor molecule in the forebrain of the male Syrian hamster ( Mesocricetus auratus ) has been studied with a novel antiserum directed against the C-terminus of the leumorphin [dynorphin B (1–29)] peptide product. C-peptide staining in sections from colchicine-treated hamsters is compared to staining in sections from untreated animals. In addition, the pattern of C-peptide immunostaining in hamster brain is compared to that in the rat brain. Finally, the C-peptide immunolabeling patterns in hamsters and rats are compared to those obtained with antisera to dynorphin A (1–17) and dynorphin B (1–13). Areas of heaviest prodynorphin immunoreactivity in the hamster include the hippocampal formation, lateral septum, bed nucleus of the stria terminalis, medial preoptic area, medial and central amygdaloid nuclei, ventral pallidum, substantia nigra, and numerous hypothalamic nuclei. Although this C-peptide staining pattern is similar to dynorphin staining reported previously in the rat, several species differences are apparent. Whereas moderate dentate gyrus granule cell staining and no CA4 cell staining have been reported in the rat hippocampal formation, intense immunostaining in the dentate gyrus and CA4 cell labeling are observed in the hamster. In addition, the medial preoptic area, bed nucleus of the stria terminalis, and medial nucleus of the amygdala stain lightly for prodynorphin-containing fibers and cells in the rat, compared to heavy cell and fiber staining in the hamster in all three of these regions. In the rat there is no differential staining between tissues processed with the C-peptide, dynorphin A, and dynorphin B antisera, but numerous areas of the hamster brain show striking differences. In most hamster brain areas containing prodynorphin peptides, the C-peptide antiserum immunolabels more cells and fibers than the dynorphin B antiserum, which in turn labels more cells and fibers than dynorphin A antiserum. However, exceptions to this hierarchy of staining intensity are found in the lateral hypothalamus, substantia nigra, arcuate nucleus, and habenula. The differences in staining patterns between rat and hamster are greatest when C-peptide antiserum is used; apparent species differences are present, though less pronounced, in dynorphin B– and dynorphin A–immunostained material.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50046/1/902880302_ftp.pd
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