275 research outputs found

    Lunar Landing Trajectory Design for Onboard Hazard Detection and Avoidance

    Get PDF
    The Autonomous Landing and Hazard Avoidance Technology (ALHAT) Project is developing the software and hardware technology needed to support a safe and precise landing for the next generation of lunar missions. ALHAT provides this capability through terrain-relative navigation measurements to enhance global-scale precision, an onboard hazard detection system to select safe landing locations, and an Autonomous Guidance, Navigation, and Control (AGNC) capability to process these measurements and safely direct the vehicle to a landing location. This paper focuses on the key trajectory design issues relevant to providing an onboard Hazard Detection and Avoidance (HDA) capability for the lander. Hazard detection can be accomplished by the crew visually scanning the terrain through a window, a sensor system imaging the terrain, or some combination of both. For ALHAT, this hazard detection activity is provided by a sensor system, which either augments the crew s perception or entirely replaces the crew in the case of a robotic landing. Detecting hazards influences the trajectory design by requiring the proper perspective, range to the landing site, and sufficient time to view the terrain. Following this, the trajectory design must provide additional time to process this information and make a decision about where to safely land. During the final part of the HDA process, the trajectory design must provide sufficient margin to enable a hazard avoidance maneuver. In order to demonstrate the effects of these constraints on the landing trajectory, a tradespace of trajectory designs was created for the initial ALHAT Design Analysis Cycle (ALDAC-1) and each case evaluated with these HDA constraints active. The ALHAT analysis process, described in this paper, narrows down this tradespace and subsequently better defines the trajectory design needed to support onboard HDA. Future ALDACs will enhance this trajectory design by balancing these issues and others in an overall system design process

    The New Eclipsing Cataclysmic Variable SDSS 154453+2553

    Full text link
    The cataclysmic variable SDSS154453+2553 was recently identified in the Sloan Digital Sky Survey. We obtained spectra and photometry at the MDM Observatory, which revealed an eclipse with a 6.03 hour period. The H{\alpha} emission line exhibits a strong rotational disturbance during eclipse, indicating that it arises in an accretion disk. A contribution from an M-type companion is also observed. Time-series photometry during eclipse gives an ephemeris of 2454878.0062(15) + 0.251282(2)E. We present spectroscopy through the orbit and eclipse photometry. Our analysis of the secondary star indicates a distance of 800 {\pm} 180 pc.Comment: 6 pages, 3 figures, Accepted for publication in PAS

    The 2011 February superoutburst of the dwarf nova SDSS J112003.40+663632.4

    Get PDF
    We report unfiltered photometry of SDSS J112003.40+663632.4 during the 2011 February outburst which revealed the presence of superhumps with peak-to-peak amplitude of up to 0.22 magnitudes showing this to be an SU UMa type dwarf nova. The outburst amplitude was 5.4 magnitudes above mean quiescence and it lasted at least 12 days. The mean superhump period during the plateau phase was Psh = 0.07057(19) d.Comment: Accepted for publication in the Journal of the British Astronomical Association. 12 pages, 5 figure

    Choosing and Using a Co-Packer

    Get PDF
    Co-packing, also known as contract packaging, is when a company contracts with another company to manufacture and package foods that the original company will sell. Products on the market that have been co-packed range from nationally known brands to those sold under private labels. The use of co-packers has become extremely popular with entrepreneurs who have a product idea but lack the $100,000 or more needed to set up a manufacturing facility to produce the product. In addition, many entrepreneurs starting a foods business find that, in today’s market conditions, greater profits are achieved through sales and marketing innovations than by what is done in manufacturing. So, if a company has limited resources, they may get more profit using these resources to develop efficient marketing procedures rather than spending them on setting up manufacturing operations

    Securing the Internet of Healthcare

    Get PDF
    Cybersecurity, which includes the security of information technology (IT), is critical to ensuring that society trusts, and therefore can benefit from, modern technology. Problematically, though, rarely a day goes by without a news story related to how critical data has been exposed, exfiltrated, or otherwise inappropriately used or accessed as a result of supply chain vulnerabilities. From the Russian government’s campaign to influence the 2016 U.S. presidential election to the September 2017 Equifax breach of more than 140 million Americans’ credit reports, cyber risk has become a topic of conversation in boardrooms and the White House, on Wall Street and main street. But these discussions often miss the problems replete in the expansive supply chains on which many of these products and services we depend on are built; this is particularly true in the medical device context. The problem recently made national news with the voluntary recall of more than 400,000 pacemakers that were found to be vulnerable to hackers, necessitating a firmware update. This Article explores the myriad vulnerabilities in the supply chain for medical devices, investigates existing FDA cybersecurity and privacy regulations to identify any potential governance gaps, and suggests a path forward to boost cybersecurity due diligence for manufacturers by making use of new approaches and technologies, including blockchain

    Simultaneity

    Get PDF
    Catalog for the exhibition Simultaneity held at the Seton Hall University Walsh Gallery, January 20 - March 14, 2014. Curated by Gabriel Phipps. Includes essays by Joe Fyfe and Gabriel Phipps. Includes color illustration
    • …
    corecore