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Integrated Magnetic Memory for Embedded Computing Systems

Kenneth J. Hass, Gregory Donohoe, Yang-Ki Hong, Byoung-Chul Choi, Kelly DeGregorio, Richard Hayhurst
2007 2007 IEEE Aerospace Conference  
This paper describes a new nonvolatile memory technology being developed for embedded computing. Based on a Magnetic Tunneling Junction (MTJ) cell, these devices will be integrated into a radiation-hard SOI CMOS process, to replace conventional flip flops and small on-chip memories. These nonvolatile memory cells will form an integral part of on-chip power management. Memory density is the primary driver for commercial MRAMs, which are designed using an X-Y addressing scheme. Current pulses on
more » ... wo orthogonal wires generate a magnetic field, which is strong enough to reprogram a cell at the intersection between the two wires, and nowhere else. This requires that the cells be very uniform in their sensitivity, and optimized for magnetic "selectivity," so that only the desired cells are programmed. Designed as replacements for flip-flops and latches, the Embedded Magnetic Memory uses a pair of MTJ cells in a differential scheme. The differential arrangement mitigates concerns of process variation, but introduces a new set of challenges. Each cell will be programmed by a single current pulse. The challenge is to design the cells and the programming structures to make efficient use of the magnetic field,
doi:10.1109/aero.2007.353103 fatcat:rhta3pgqwzc4fp5aelcrlz774q

A case study for assured containment

Kelly J. Hayhurst, Jeffrey M. Maddalon, Natasha A. Neogi, Harry A. Verstynen
2015 2015 International Conference on Unmanned Aircraft Systems (ICUAS)  
doi:10.1109/icuas.2015.7152299 fatcat:3ixinmg3j5bajof6bi2wjeawfq

SAFEGUARD: An assured safety net technology for UAS

Evan T. Dill, Steven D. Young, Kelly J. Hayhurst
2016 2016 IEEE/AIAA 35th Digital Avionics Systems Conference (DASC)  
Based on these regulatory approaches, Hayhurst et al. recently performed a case study to develop design standards for a 1000-lb unmanned rotorcraft with specific consideration for its operation in a rural  ... 
doi:10.1109/dasc.2016.7778009 fatcat:vzqtj3zdyfbzpbo2lmqp6oyms4

Some impacts of risk-centric certification requirements for UAS

Natasha A. Neogi, Kelly J. Hayhurst, Jeffrey M. Maddalon, Harry A. Verstynen
2016 2016 International Conference on Unmanned Aircraft Systems (ICUAS)  
This paper discusses results from a recent study that investigates certification requirements for an unmanned rotorcraft performing agricultural application operations. The process of determining appropriate requirements using a risk-centric approach revealed a number of challenges that could impact larger UAS standardization efforts. Fundamental challenges include selecting the correct level of abstraction for requirements to permit design flexibility, transforming human-centric operational
more » ... uirements to aircraft airworthiness requirements, and assessing all hazards associated with the operation.
doi:10.1109/icuas.2016.7502531 fatcat:7zy5h7dz2jex5if5kj6ujvm3pu

SAFEGUARD: Progress and test results for a reliable independent on-board safety net for UAS

Russell V. Gilabert, Evan T. Dill, Kelly J. Hayhurst, Steven D. Young
2017 2017 IEEE/AIAA 36th Digital Avionics Systems Conference (DASC)  
As demands increase to use unmanned aircraft systems (UAS) for a broad spectrum of commercial applications, regulatory authorities are examining how to safely integrate them without compromising safety or disrupting traditional airspace operations. For small UAS, several operational rules have been established; e.g., do not operate beyond visual line-ofsight, do not fly within five miles of a commercial airport, do not fly above 400 ft above ground level. Enforcing these rules is challenging
more » ... UAS, as evidenced by the number of incident reports received by the Federal Aviation Administration (FAA). This paper reviews the development of an onboard system -Safeguarddesigned to monitor and enforce conformance to a set of operational rules defined prior to flight (e.g., geospatial stay-out or stay-in regions, speed limits, and altitude constraints). Unlike typical geofencing or geo-limitation functions, Safeguard operates independently of the off-the-shelf UAS autopilot and is designed in a way that can be realized by a small set of verifiable functions to simplify compliance with existing standards for safety-critical systems (e.g. for spacecraft and manned commercial transportation aircraft systems). A framework is described that decouples the system from any other devices on the UAS as well as introduces complementary positioning source(s) for applications that require integrity and availability beyond what can be provided by the Global Positioning System (GPS). This paper summarizes the progress and test results for Safeguard research and development since presentation of the design concept at the 35th DASC (2016). Significant accomplishments include completion of software verification and validation in accordance with NASA standards for spacecraft systems (to Class B), development of improved hardware prototypes, development of a simulation platform that allows for hardware-in-the-loop testing and fast-time Monte Carlo evaluations, and flight testing on multiple air vehicles. Integration testing with NASA's UAS Traffic Management (UTM) service-oriented architecture was also demonstrated.
doi:10.1109/dasc.2017.8102087 fatcat:b24wekbkj5ejfhsqss7z5grjua

Considerations of Unmanned Aircraft Classification for Civil Airworthiness Standards

Jeffrey M. Maddalon, Kelly J. Hayhurst, Allan Morris, Harry Verstynen
2013 AIAA Infotech@Aerospace (I@A) Conference   unpublished
remain in realizing routine and safe operation of these aircraft 2 . One aspect of the regulatory challenge is to establish the airworthiness standards for UAS. Other organizations, especially militaries, have developed sets of airworthiness standards for their vehicles 3 . Such standards are helpful, but may not adequately address risks associated with civil operation in the NAS, or adequately "accommodate the diversity of UAS design, capability, and operations" 4 expected for commercial
more » ... ations. Indeed, as reported by Clothier, et al., "much effort is being devoted to the definition of standards specific to UAS (e.g., the specification of prescriptive requirements on aspects of their design, maintenance, manufacture and operation). However, little consideration has been given to how these standards and regulations may be appropriately applied across the diversity of UAS, their operations and the mitigation strategies widely employed." 5 his paper examines the broad range of UAS by addressing one specific aspect of the airworthiness problem: namely, that of grouping similar UAS together for the purpose of assigning airworthiness standards, that is, UAS classification. Specifically this paper examines the classification problem through the perspective of using physical characteristics of the aircraft and its operational capabilities and limitations to place it in a group wherein all members would be assigned the same airworthiness standards. These characteristics and capabilities are referred to here as classification factors. This work leverages an initial survey of aircraft classification documented in Maddalon, et al. 6 Classification of aircraft for the purpose of assigning airworthiness standards should account for hazards and their associated risks, in addition to accounting for substantive differences in design features. In this work, safety risk is the primary type of risk of interest, as opposed to other types of risk, such as economic risk or missionspecific risk. The FAA defines safety risk as the composite of predicted severity and likelihood of the potential effect of a hazard that could cause harm to persons or property damage. 7 Ideally, if safety risks inherent in different types of UAS and their operations could be identified, then UAS classification could be fashioned around these identified risks. Although this is conceptually appealing, comprehensive risk identification across the spectrum of UAS has proven difficult. From a high-level perspective, DeGarmo made one of the best attempts 2 . Instead of attempting to identify all risks across all types of UAS, the research approach described in this paper involved examining airworthiness classification approaches from a wide variety of organizations, and then identifying and evaluating the various factors used in these approaches. The classification system used for allocating airworthiness standards to civil manned aircraft by the Federal Aviation Administration (FAA) was examined first, followed by a survey of proposed classification approaches for UAS. Presumably, each organization, whether military or civilian, classifies aircraft to address the risks that they deem most relevant to safety, and, consequently, the factors that correspond to the risks deemed most important to safety. A basic hypothesis of this research is that the classification approach used for manned aircraft today is appropriate for UAS if the factors used to group manned aircraft are sufficient for grouping UAS for the purpose of assigning appropriate airworthiness standards. If those factors do not adequately capture either distinct design attributes of UAS or operational aspects that warrant different standards, then other factors should be considered. This analysis is both preliminary and subjective, especially due to the high degree of uncertainty in the specific hazards and risks associated with UAS operation in the NAS. The intent of this work is to offer preliminary observations to help guide further investigation, rather than precise conclusions. As additional hazard data is collected through increased operation of UAS, safety issues and risks can be better characterized and managed through appropriate classification. Because classification of UAS is a regulatory topic, this research relies heavily on interpretation of the Federal Aviation Regulations, denoted in the rest of the paper as 14CFRX.Y ** . This paper presents one view of the purpose and intent of the Federal Aviation Regulations with respect to airworthiness certification, and how those regulations may apply to UAS. It is not intended to be a complete or expert treatment of the subject. This paper should not be considered or used as an authoritative source for regulatory guidance, nor does it represent current or future US Government or FAA policy. Before proceeding, a note on terminology may be helpful. Over the years, many terms have been used to describe unmanned aircraft; for example, drone, unmanned aerial vehicle (UAV), as well as unmanned aircraft system (UAS), which is the term this paper will use. A UAS is any aircraft without a pilot on board, including associated control station, communication links and ancillary equipment. Furthermore, this paper uses the term conventionally piloted aircraft or CPA 8 to indicate an aircraft with a pilot on board. This report is organized as follows. Section II outlines the scope of discussion on UAS classification and why classification of UAS is ultimately important to access to the NAS, and Section III defines terminology from the ** The notation 14CFRX.Y should be read as, "Title 14 of the Code of Federal Regulations, part X, section Y." This notation will be used throughout this paper when referring to specific regulations.
doi:10.2514/6.2013-5216 fatcat:xb3h2ukh3rchhjrwwbpjobovie

Page 821 of The Congregational Magazine Vol. 18, Issue 132 [page]

1835 The Congregational Magazine  
Hackett — Hayhurst R, M. Griffiths Samuel Bell Bethesda Chapel, Dun- can-street Hanover Chap., Mill-st. John Kelly. W. Fletcher Newington Chap., Ren- Gloucester-st. Cha .  ...  Bradley J. Jones, Welsh R. Fletcher J. Griffiths, Welsh J. Gwyther y' Robert 8. M‘All, LL.D. George Taylor James Griffin John A. Coombs W. Alexander J. Leigh — Dawes J. Holgate Jokn Williams J.  ... 

Page 52 of American Journal of Pharmacy and the Sciences Supporting Public Health Vol. 71, Issue [page]

1899 American Journal of Pharmacy and the Sciences Supporting Public Health  
Susan Hayhurst, M.D, T. M. Rohrer. Harry Cox. R. J. Williams. N. O. Harris. J. Lawson Crowthers, E. F. Kaempfer. Chas. A. Eckels. Geo. M. Beringer. W. J. Scott. J. W. Smith. Frank W. Ely. C. J.  ...  J. Durbin. W. A. Dorman. J. Addison Eberly. B. A. Kelly P. Henry Utech. John H. Folkens. Geo. P. Ringler. Frank Luersson. C. W. Warrington. R. H. Lackey. T. W. Hargreaves. H. J. Fiet, M.D. J. H.  ... 

Page 1848 of Management & Marketing Abstracts Vol. 27, Issue 11 [page]

2002 Management & Marketing Abstracts  
M, 4063 Keller K L, 4323, 4342 Kelly L M, 4421 Kelly S L, 4069 Kemmis S, 4187 Kets de Vries M F R, 4058 Khurana R, 4080 Killen C P, 4176 Kim W C, 4430 Kimmel A J, 4281 Klaff L G, 4201 Knight J A, 4067  ...  Hammond D, 4257 Hamrin U, 4118 Hannigan T, 4388 Harding D, 4082 Harrington S, 4302 Harrison K, 4230 Hartmann L C, 4442 Harvey M, 4066 Hayhurst D, 4103 Hayward D, 4298 Heligren B, 4405 Hemp P, 4434 Herrera  ... 

Page 695 of The Journal of the Operational Research Society Vol. 53, Issue 6 [page]

2002 The Journal of the Operational Research Society  
Jozefowska H Juel C Kao P Kawalek M Kelly P Keys HV Kher JB Kidd Y-D Kim MW Kirby JPC Kleijnen JH Klein A Kleywegt G Kochman H Kreher M Krishnamoorthy GJ Kyparisis J Kyparisis M Laguna KK Lai DL Lane G  ...  Gilchrist BC Giri JJ Glen B Golany D Golenko-Ginzburg VS Gordon SK Goyal G Gregory CA Grosso F Guder A Gunasekaran D Gupta JND Gupta M Hababou RI Hall T Hanne JB Hardaker AS Harding E Hassini NAJ Hastings G Hayhurst  ... 

Page 676 of The Journal of the Operational Research Society Vol. 54, Issue 6 [page]

2003 The Journal of the Operational Research Society  
Jozefowska H Juel C Kao BY Kara S Karabati P Kawalek M Kelly P Keskinocak P Keys  ...  Gregory CA Grosso F Guder A Gunasekaran D Gupta JND Gupta S Gustafson F Gzara M Hababou D Hadley C Haksever RI Hall T Hanne JB Hardaker AS Harding MA Hariga A Harrison TP Harrison E Hassini NAJ Hastings G Hayhurst  ... 

Page 19 of Journal of Economic Entomology Vol. 2, Issue 1 [page]

1909 Journal of Economic Entomology  
C Paul Hayhurst. Bussey Institution, Forest Hills, Boston, Mass. C. E. Hood, Dallas, Texas. C. W. Hooker, Amherst, Mass. J. R. Horton, Logan, Utah. J. A. Hyslop, Washington, D. C E. L. A. H.  ...  Kelly, Washington, D. C. Frederick Knab, Washington, D. C. E. J. Kraus, Washington, D. C. A. C. Lewis, Atlanta, Ga. + 40 Jenne, Washington, D. C.  ... 

Page 47 of American Journal of Pharmacy and the Sciences Supporting Public Health Vol. 53, Issue [page]

1881 American Journal of Pharmacy and the Sciences Supporting Public Health  
K mr ow > PrSsmesoss J. D. McFerran. E. L. Aughinbaugh. L. Manz. M. Kratz. Backer, Moore & Mein. rad Ma  ...  ., Hart, Joseph, Hayes, George Washington, Hayhurst, Susan, Hertsch, Bernhard August, Hinchman, Walter Lippincott, Hodgson, Francis, Hoke, Willis Andrew Balch, Holmes, M.  ... 

Page 558 of The Journal of Business Vol. 50, Issue 4 [page]

1977 The Journal of Business  
GEORGE HAYHURST, California State (Fullerton), Sept. 1977. ROBERT J. HEMSTEAD, assoc. prof., actuarial science, Michigan. JAN W. HENKEL, asst. prof., Georgia, Sept. 1977. NED C.  ...  KELLY GHEYARA, asst. prof., accounting, Texas Christian, Aug. 1977. DAVID GILFILLAN, asst. prof., management, Temple, Jan. 1977. ROY H. GLEN, visiting asst. prof., Illinois (Urbana), Aug. 1977.  ... 

Page 96 of American Society of Civil Engineers. Proceedings of the American Society of Civil Engineers Vol. 65, Issue 4 [page]

1939 American Society of Civil Engineers. Proceedings of the American Society of Civil Engineers  
J. Dyer, Contact Member; Edward Gant, President; James Roy Kelly, Secretary, 2004 Broad St., Nashville, Tenn. VERMONT, UNIvERSITY oF, STUDENT CHAPTER, ORGANIZED 1937. (19 Members.) Dean George F.  ...  Thomas J. McCormick, Acting Faculty Adviser; Prof. John J. Sweeney, Contact Member; James J. Carroll, President; Joseph Gallagher, Secretary, Villanova College, Villanova, Pa.  ... 
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