Science.gov

Sample records for agile beam steering

  1. Data transfer through beam steering using agile lensing

    NASA Astrophysics Data System (ADS)

    Arshad, Muhammad Assad; Reza, Syed Azer; Muhammad, Ahsan

    2016-04-01

    This paper presents a data transfer scheme using multi-focus tunable lenses. The design involves the use of a standard laser source and a variable focus agile lens to steer to the laser beam that passes through the lens. In our proposed system, the beam steer angle depends on an input electrical signal which drives the tunable lens. Therefore the beam steer angle is made to follow the variations in the input electrical drive signal. This is extremely interesting for data transfer applications as the data signal can be used as the input drive signal to the lens. The laser beam is steered according to the input data voltage levels and when the beam is incident on a photo-detector of a finite size, only a fraction of its total incident optical power is received by the photo-detector. This power contribution is proportional to the fraction of the total number of photons per unit area which are incident on the active area of the detector. The remaining photons which are not incident on the photo-detector do not contribute to the received power at the photo-detector. We present the theory of beam steering through a tunable lens and present a theoretical framework which governs data transfer through the proposed method. We also present the transfer function of the proposed system which helps us to calculate its essential theoretical performance parameters such as modulation depth and bit error rates. We also present experimental results to demonstrate efficient data transfer through the proposed method. As tunable lenses are primarily deployed in motion-free multi-focus cameras hence most of the modern portable devices such as cellphones and tablets use these lenses to operate the in-built variable focus cameras that are part of these devices. Because tunable lenses are commonly present in several different portable devices, the proposed method of data transfer between two devices is highly promising as it expands the use of the already deployed tunable lenses with

  2. Laser beam steering device

    NASA Technical Reports Server (NTRS)

    Motamedi, M. E.; Andrews, A. P.; Gunning, W. J.

    1993-01-01

    Agile beam steering is a critical requirement for airborne and space based LIDAR and optical communication systems. Design and test results are presented for a compact beam steering device with low inertia which functions by dithering two complementary (positive and negative) binary optic microlens arrays relative to each other in directions orthogonal to the direction of light propagation. The miniaturized system has been demonstrated at scan frequencies as high as 300 Hz, generating a 13 x 13 spot array with a total field of view of 2.4 degrees. The design is readily extendable to a 9.5 degree field of view and a 52 x 52 scan pattern. The system is compact - less than 2 in. on a side. Further size reductions are anticipated.

  3. Holographic memory using beam steering

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin (Inventor); Hanan, Jay C. (Inventor); Reyes, George F. (Inventor); Zhou, Hanying (Inventor)

    2007-01-01

    A method, apparatus, and system provide the ability for storing holograms at high speed. A single laser diode emits a collimated laser beam to both write to and read from a photorefractice crystal. One or more liquid crystal beam steering spatial light modulators (BSSLMs) steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal.

  4. Holographic memory using beam steering

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin (Inventor); Hanan, Jay C. (Inventor); Reyes, George F. (Inventor); Zhou, Hanying (Inventor)

    2006-01-01

    A method, apparatus, and system provide the ability for storing holograms at high speed. A single laser diode emits a collimated laser beam to both write to and read from a photorefractice crystal. One or more liquid crystal beam steering spatial light modulators (BSSLMs) or Micro-Electro-Mechanical Systems (MEMS) mirrors steer a reference beam, split from the collimated laser beam, at high speed to the photorefractive crystal.

  5. Automated beam steering using optimal control

    SciTech Connect

    Allen, C. K.

    2004-01-01

    We present a steering algorithm which, with the aid of a model, allows the user to specify beam behavior throughout a beamline, rather than just at specified beam position monitor (BPM) locations. The model is used primarily to compute the values of the beam phase vectors from BPM measurements, and to define cost functions that describe the steering objectives. The steering problem is formulated as constrained optimization problem; however, by applying optimal control theory we can reduce it to an unconstrained optimization whose dimension is the number of control signals.

  6. A computer algorithm for automatic beam steering

    SciTech Connect

    Drennan, E.

    1992-06-01

    Beam steering is done by modifying the current in a trim or bending magnet. If the current change is the right amount the beam can be made to bend in such a manner that it will hit a swic or BPM downstream from the magnet at a predetermined set point. Although both bending magnets and trim magnets can be used to modify beam angle, beam steering is usually done with trim magnets. This is so because, during beam steering the beam angle is usually modified only by a small amount which can be easily achieved with a trim magnet. Thus in this note, all steering magnets will be assumed to be trim magnets. There are two ways of monitoring beam position. One way is done using a BPM and the other is done using a swic. For simplicity, beam position monitoring in this paper will be referred to being done with a swic. Beam steering can be done manually by changing the current through a trim magnet and monitoring the position of the beam downstream from the magnet with a swic. Alternatively the beam can be positioned automatically using a computer which periodically updates the current through a specific number of trim magnets. The purpose of this note is to describe the steps involved in coming up with such a computer program. There are two main aspects to automatic beam steering. First a relationship between the beam position and the bending magnet is needed. Secondly a beamline setup of swics and trim magnets has to be chosen that will position the beam according to the desired specifications. A simple example will be looked at that will show that once a mathematical relationship between the needed change of the beam position on a swic and the change in trim currents is established, a computer could be programmed to calculate and update the trim currents.

  7. Digital Controller For Laser-Beam-Steering Subsystem: Part 2

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon; Voisinet, Leeann

    1995-01-01

    A report presents additional information about laser-beam-steering apparatus described in "Digital Controller for Laser-Beam-Steering Subsystem" (NPO-19193) and "More About Beam-Steering Subsystem for Laser Communication" (NPO-19381). Reiterates basic principles of operation of beam-steering subsystem, with emphasis on modes of operation, basic design concepts, and initial experiments on partial prototype of apparatus.

  8. Highly sensitive beam steering with plasmonic antenna

    PubMed Central

    Rui, Guanghao; Zhan, Qiwen

    2014-01-01

    In this work, we design and study a highly sensitive beam steering device that integrates a spiral plasmonic antenna with a subwavelength metallic waveguide. The short effective wavelength of the surface plasmon polaritons (SPPs) mode supported by the metallic waveguide is exploited to dramatically miniaturize the device and improve the sensitivity of the beam steering. Through introducing a tiny displacement of feed point with respect to the geometrical center of the spiral plasmonic antenna, the direction of the radiation can be steered at considerably high angles. Simulation results show that steering angles of 8°, 17° and 34° are obtainable for a displacement of 50 nm, 100 nm and 200 nm, respectively. Benefiting from the reduced device size and the shorter SPP wavelength, the beam steering sensitivity of the beam steering is improved by 10-fold compared with the case reported previously. This miniature plasmonic beam steering device may find many potential applications in quantum optical information processing and integrated photonic circuits. PMID:25091405

  9. Beam Steering Devices Reduce Payload Weight

    NASA Technical Reports Server (NTRS)

    2012-01-01

    Scientists have long been able to shift the direction of a laser beam, steering it toward a target, but often the strength and focus of the light is altered. For precision applications, where the quality of the beam cannot be compromised, scientists have typically turned to mechanical steering methods, redirecting the source of the beam by swinging the entire laser apparatus toward the target. Just as the mechanical methods used for turning cars has evolved into simpler, lighter, power steering methods, so has the means by which researchers can direct lasers. Some of the typical contraptions used to redirect lasers are large and bulky, relying on steering gimbals pivoted, rotating supports to shift the device toward its intended target. These devices, some as large and awkward as a piece of heavy luggage, are subject to the same issues confronted by mechanical parts: Components rub, wear out, and get stuck. The poor reliability and bulk not to mention the power requirements to run one of the machines have made mechanical beam steering components less than ideal for use in applications where weight, bulk, and maneuverability are prime concerns, such as on an unmanned aerial vehicle (UAV) or a microscope. The solution to developing reliable, lighter weight, nonmechanical steering methods to replace the hefty steering boxes was to think outside the box, and a NASA research partner did just that by developing a new beam steering method that bends and redirects the beam, as opposed to shifting the entire apparatus. The benefits include lower power requirements, a smaller footprint, reduced weight, and better control and flexibility in steering capabilities. Such benefits are realized without sacrificing aperture size, efficiency, or scanning range, and can be applied to myriad uses: propulsion systems, structures, radiation protection systems, and landing systems.

  10. Tunable beam steering enabled by graphene metamaterials.

    PubMed

    Orazbayev, B; Beruete, M; Khromova, I

    2016-04-18

    We demonstrate tunable mid-infrared (MIR) beam steering devices based on multilayer graphene-dielectric metamaterials. The effective refractive index of such metamaterials can be manipulated by changing the chemical potential of each graphene layer. This can arbitrarily tailor the spatial distribution of the phase of the transmitted beam, providing mechanisms for active beam steering. Three different beam steerer (BS) designs are discussed: a graded-index (GRIN) graphene-based metamaterial block, an array of metallic waveguides filled with graphene-dielectric metamaterial and an array of planar waveguides created in a graphene-dielectric metamaterial block with a specific spatial profile of graphene sheets doping. The performances of the BSs are numerically analyzed, showing the tunability of the proposed designs for a wide range of output angles (up to approximately 70°). The proposed graphene-based tunable beam steering can be used in tunable transmitter/receiver modules for infrared imaging and sensing.

  11. More About Beam-Steering Subsystem For Laser Communication

    NASA Technical Reports Server (NTRS)

    Page, Norman A.; Chen, Chien-Chu; Hemmati, Hamid; Lesh, James R.

    1995-01-01

    Two reports present additional information about developmental beam-steering subsystem of laser-communication system. Aspects of this subsystem described previously in "Beam-Steering Subsystem for Laser Communication" (NPO-19069) and "Digital Controller for Laser-Beam-Steering Subsystem" (NPO-19193). Reports reiterate basic principles of operation of beam-steering subsystem and of laser-communication system as whole. Also presents some of details of optical and mechanical design of prototype of subsystem, called Optical Communication Demonstrator.

  12. Laser steering of particle beams: Refraction and reflection ofparticle beams

    SciTech Connect

    Esarey, Eric; Katsouleas, T.; Mori, W.B.; Dodd, E.; Lee, S.; Hemker, R.; Clayton, C.; Joshi, C.

    1999-11-01

    The co-propagation of an intense particle beam with an ionizing laser beam in a working gas/plasma is considered. When the axes of the laser and particle beam are not aligned, then asymmetric plasma lensing results in a net dipole field acting on the particle beam. The particle beam can be steered or bent (as well as focused) by steering the laser. An analogy is made between the bending of the particle beam by collective effects at a plasma boundary and the refraction or reflection of light at an interface. This mechanism of particle steering may be of interest in applications for which permanent magnets are inconvenient of a fast turn on is required. 3-D particle-in-cell simulations and relevance to a recent experiment are discussed.

  13. SPS Beam Steering for LHC Extraction

    SciTech Connect

    Gianfelice-Wendt, Eliana; Bartosik, Hannes; Cornelis, Karel; Norderhaug Drøsdal, Lene; Goddard, Brennan; Kain, Verena; Meddahi, Malika; Papaphilippou, Yannis; Wenninger, Jorg

    2014-07-01

    The CERN Super Proton Synchrotron accelerates beams for the Large Hadron Collider to 450 GeV. In addition it produces beams for fixed target facilities which adds complexity to the SPS operation. During the run 2012-2013 drifts of the extracted beam trajectories have been observed and lengthy optimizations in the transfer lines were performed to reduce particle losses in the LHC. The observed trajectory drifts are consistent with the measured SPS orbit drifts at extraction. While extensive studies are going on to understand, and possibly suppress, the source of such SPS orbit drifts the feasibility of an automatic beam steering towards a “golden” orbit at the extraction septa, by means of the interlocked correctors, is also being investigated. The challenges and constraints related to the implementation of such a correction in the SPS are described. Simulation results are presented and a possible operational steering strategy is proposed.

  14. Adaptive beam tracking and steering via electrowetting-controlled liquid prism

    SciTech Connect

    Cheng, JT; Chen, CL

    2011-11-07

    We report an electrowetting-controlled optofluidic system for adaptive beam tracking and agile steering. With two immiscible fluids in a transparent cell, we can actively control the contact angle along the fluid-fluid-solid tri-junction line and hence the orientation of the fluid-fluid interface via electrowetting. The naturally formed meniscus between the two liquids can function as an optical prism. We have fabricated a liquid prism module with an aperture size of 10 mm -10mm. With 1 wt.% KCl and 1 wt.% Sodium Dodecyl Sulfate added into deionized water, the orientation of the water-silicone oil interface has been modulated between -26 degrees and 26 degrees that can deflect and steer beam within the incidence angle of 0 degrees-15 degrees. The wide-range beam tracking and steering enables the liquid prism work as an electrowetting solar cell. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3660578

  15. Digital Controller For Laser-Beam-Steering Subsystem

    NASA Technical Reports Server (NTRS)

    Ansari, Homayoon

    1995-01-01

    Report presents additional information about proposed apparatus described in "Beam-Steering Subsystem for Laser Communication" (NPO-19069). Discusses design of digital beam-steering control subsystem and, in particular, that part of design pertaining to digital compensation for frequency response of steering mirror.

  16. Indexing system for optical beam steering

    NASA Technical Reports Server (NTRS)

    Sullivan, Mark T.; Cannon, David M.; Debra, Daniel B.; Young, Jeffrey A.; Mansfield, Joseph A.; Carmichael, Roger E.; Lissol, Peter S.; Pryor, G. M.; Miklosy, Les G.; Lee, Jeffrey H.

    1990-01-01

    This paper describes the design and testing of an indexing system for optical-beam steering. The cryogenic beam-steering mechanism is a 360-degree rotation device capable of discrete, high-precision alignment positions. It uses low-precision components for its rough alignment and kinematic design to meet its stringent repeatability and stability requirements (of about 5 arcsec). The principal advantages of this design include a decoupling of the low-precision, large angular motion from the high-precision alignment, and a power-off alignment position that potentially extends the life or hold time of cryogenic systems. An alternate design, which takes advantage of these attributes while reducing overall motion, is also presented. Preliminary test results show the kinematic mount capable of sub-arc second repeatability.

  17. An Agile Beam Transmit Array Using Coupled Oscillator Phase Control

    NASA Technical Reports Server (NTRS)

    Pogorzelski, Ronald S.; Scaramastra, Rocco P.; Huang, John; Beckon, Robert J.; Petree, Steve M.; Chavez, Cosme

    1993-01-01

    A few years ago York and colleagues suggested that injection locking of voltage controlled oscillators could be used to implement beam steering in a phased array [I]. The scheme makes use of the fact that when an oscillator is injection locked to an external signal, the phase difference between the output of the oscillator and the injection signal is governed by the difference between the injection frequency and the free running frequency of the oscillator (the frequency to which the oscillator is tuned). Thus, if voltage controlled oscillators (VCOs) are used, this phase difference is controlled by an applied voltage. Now, if a set of such oscillators are coupled to nearest neighbors, they can be made to mutually injection lock and oscillate as an ensemble. If they are all tuned to the same frequency, they will all oscillate in phase. Thus, if the outputs are connected to radiating elements forming a linear array, the antenna will radiate normal to the line of elements. Scanning is accomplished by antisymmetrically detuning the end oscillators in the array by application of a pair of appropriate voltages to their tuning ports. This results in a linear phase progression across the array which is just the phasing required to scan the beam. The scan angle is determined by the degree of detuning. We have constructed a seven element one dimensional agile beam array at S-band based on the above principle. Although, a few such arrays have been built in the past, this array possesses two unique features. First, the VCO MMICs have buffer amplifiers which isolate the output from the tuning circuit, and second, the oscillators are weakly coupled to each other at their resonant circuits rather than their outputs. This results in a convenient isolation between the oscillator array design and the radiating aperture design. An important parameter in the design is the so called coupling phase which determines the phase shift of the signals passing from one oscillator to its

  18. ICESat-2 ATLAS Beam Steering Mechanism (BSM)

    NASA Technical Reports Server (NTRS)

    Hinkle, Matthew

    2015-01-01

    This work covers the design and test of a beam steering mechanism (BSM) used to accurately guide a laser on the Advanced Topographic Laser Altimeter System (ATLAS) down to Earth in order to measure elevation. It describes the main components in the BSM that allows it to perform and meet stringent requirements. Requirements of the BSM include two-axis steering of the transmitted laser beam, +-5000 uRad mechanical motion in each axis, and 1.5 uRad RMS pointing stability among many other requirements. The BSM uses four voice coil actuators in order to locate the mirror at the angle we need. There are four Differential Position Sensors that determine the position and angle of the mirror at all times. These sensors were verified through optical testing in both ambient and thermal conditions. Testing and extensive analyses were performed on the two-axis flexure throughout the program to check flexure thickness, positive margins, and infinite life. The mirror mount design has been modified to eliminate radial preload, while incorporating a titanium wave spring to provide an axial preload of 10.8N. The BSM underwent multiple tests in order to verify all components work as required under various conditions.

  19. Phase shifter for antenna beam steering

    NASA Astrophysics Data System (ADS)

    Jindal, Ravi; Razban, Tchanguiz

    2016-03-01

    Wide band Array Antenna operates in Ku-band (10.7-12.7 GHz) frequency composed of N×N radiating elements. This antenna aims at the reception of television satellite signals. The goal of this research is to provide better possibility of electronic beam control instead of manual or mechanical control, and design compact and low cost phase shifters to be inserted in the feeding network of this antenna. The electronic control of the phase shifter will allow the control of beam steering. The emphasis of this project will be done at the beginning on the design of a good phase shifter in Ku band. The aim of this research is to define, simulate, release and measure a continuous phase shifter. Better reflection loss, low transmission loss, low Cost of array antennas, large range of phase-shifter, phase flatness and bandwidth will be achieved by providing better gain.

  20. ATLAS Beam Steering Mechanism Lessons Learned

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gostin, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morrell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. The high resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of the methodology to verify performance required significant effort. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite II Mission (ICESat II), which is scheduled to be launched in 2017. The ICESat II primary mission is to map the earth's surface topography for the determination of seasonal changes of ice sheet thickness and vegetation canopy thickness to establish long-term trends.

  1. Beam Steering Mechanism (BSM) Lessons Learned

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gostin, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. High resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of methodology to verify performance was a significant effortadvancement. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite 2 Mission (ICESat 2), which is scheduled to be launched in 2017. The ICESat 2 primary mission is to map the earths surface topography for the determination of seasonal changes of ice sheet thickness as well as vegetation canopy thickness.

  2. ATLAS Beam Steering Mechanism (BSM) Lessons Learned

    NASA Technical Reports Server (NTRS)

    Blumenstock, Kenneth A.; Cramer, Alexander K.; Gosten, Alan B.; Hakun, Claef F.; Haney, Paul G.; Hinkle, Matthew R.; Lee, Kenneth Y.; Lugo, Carlos F.; Matuszeski, Adam J.; Morell, Armando; Armani, Nerses V.; Bonafede, Joseph; Jackson, Molly I.; Steigner, Peter J.; Stromsdorfer, Juan J.

    2016-01-01

    This paper describes the design, testing, and lessons learned during the development of the Advanced Topographic Laser Altimeter System (ATLAS) Beam Steering Mechanism (BSM). The BSM is a 2 degree-of-freedom tip-tilt mechanism for the purpose of pointing a flat mirror to tightly control the co-alignment of the transmitted laser and the receiver telescope of the ATLAS instrument. The high resolution needs of the mission resulted in sub-arcsecond pointing and knowledge requirements, which have been met. Development of the methodology to verify performance required significant effort. The BSM will fly as part of the Ice, Cloud, and Elevation Satellite II Mission (ICESat II), which is scheduled to be launched in 2017. The ICESat II primary mission is to map the Earth's surface topography for the determination of seasonal changes of ice sheet thickness and vegetation canopy thickness to establish long-term trends.

  3. Repositioning and steering laser beam power via coherent combination of multiple Airy beams.

    PubMed

    Zhang, Ze; Ye, Zhuoyi; Song, Daohong; Zhang, Peng; Chen, Zhigang

    2013-12-10

    We study numerically and experimentally laser coherent combination (LCC) with multiple one- or two-dimensional Airy beams. It is shown that the method of LCC using Airy beams leads to a higher combining efficiency and a better feature of propagation than that using conventional Gaussian beams. Based on such coherent Airy beams combination, we propose a laser steering approach that could achieve large-angle beam steering (over 0.6°) without the need of using any mechanical steering component.

  4. Liquid Crystal-based Beam Steering Technologies for NASA Applications

    NASA Technical Reports Server (NTRS)

    Pouch, John; Nguyen, Hung; Miranda, Felix; Bos, Philip; Lavrentovich, Oleg; Wang, Xinghua; Pishnyak, Oleg; Kreminska, Liubov; Golovin, Andrii

    2006-01-01

    Liquid crystal-based beam steering devices can provide electronic beam scanning to angles above 1 milliradian, sub-microradian beam pointing accuracy, as well as wave-front correction to maintain output optical beam quality. The liquid crystal technology effort will be summarized, and the potential application of the resulting devices to NASA space-based scenarios will be described.

  5. Laser Beam Steering/shaping for Free Space Optical Communication

    NASA Technical Reports Server (NTRS)

    Wang, Xinghua; Wang, Bin; Bos, Philip J.; Anderson, James E.; Pouch, John; Miranda, Felix; McManamon, Paul F.

    2004-01-01

    The 2-D Optical Phased Array (OPA) antenna based on a Liquid Crystal On Silicon (LCoS) device can be considered for use in free space optical communication as an active beam controlling device. Several examples of the functionality of the device include: beam steering in the horizontal and elevation direction; high resolution wavefront compensation in a large telescope; and beam shaping with the computer generated kinoform. Various issues related to the diffraction efficiency, steering range, steering accuracy as well as the magnitude of wavefront compensation are discussed.

  6. Agile

    NASA Technical Reports Server (NTRS)

    Trimble, Jay Phillip

    2013-01-01

    This is based on a previous talk on agile development. Methods for delivering software on a short cycle are described, including interactions with the customer, the affect on the team, and how to be more effective, streamlined and efficient.

  7. Integrated phased array for wide-angle beam steering.

    PubMed

    Yaacobi, Ami; Sun, Jie; Moresco, Michele; Leake, Gerald; Coolbaugh, Douglas; Watts, Michael R

    2014-08-01

    We demonstrate an on-chip optical phased array fabricated in a CMOS compatible process with continuous, fast (100 kHz), wide-angle (51°) beam-steering suitable for applications such as low-cost LIDAR systems. The device demonstrates the largest (51°) beam-steering and beam-spacing to date while providing the ability to steer continuously over the entire range. Continuous steering is enabled by a cascaded phase shifting architecture utilizing, low power and small footprint, thermo-optic phase shifters. We demonstrate these results in the telecom C-band, but the same design can easily be adjusted for any wavelength between 1.2 and 3.5 μm.

  8. Temperature and frequency compensated array beam steering unit

    NASA Astrophysics Data System (ADS)

    Claborn, K. D.; Bailey, W. C.

    1986-04-01

    Beam pointing errors and sidelobes resulting from temperature variations on the aperture and power divider of a series phased array antenna operating at a plurality of selected operating channel frequencies and having uniformly spaced elements are compensated for by placing a temperature sensor on both the aperture and power divider and converting the respective temperature outputs to digital signals which are fed to a digital beam steering unit. A pair of programmed memories are included in the beam steering unit which respond to an address or pointer corresponding to the digitized temperature values and the selected operating frequency to read out stored digitized beam steering phase gradients and feed phase correction which are combined and sequentially applied at regular intervals to symmetrically located phase shifter pairs. A uniformly compensated beam is thereafter radiated at a predetermined phase angle.

  9. Radiation beam steering by cyclotron-resonance maser array

    NASA Astrophysics Data System (ADS)

    Kesar, Amit; Jerby, Eli

    1999-02-01

    A concept of power beaming by a cyclotron-resonance maser (CRM) array is presented theoretically. In this scheme, the CRM-array operates as an active phased-array antenna, and radiates directly from its output aperture. The gain and phase of each CRM element in the array are controlled by the voltage and current of its electron gun. The consequent phase difference between the CRM-element outputs enables the steering of the radiation beam in the far field. A simplified linear model is presented for a CRM-array antenna with uncoupled elements. It provides radiation patterns which demonstrate the main feature of power-beam steering. A wide angular steering range (+/-35°) is obtained by an analog electronic control of the CRM array. The feasibility of practical CRM-array antennas is discussed.

  10. Diffraction Efficiency of Thin Film Holographic Beam Steering Devices

    NASA Technical Reports Server (NTRS)

    Titus, Charles M.; Pouch, John; Nguyen, Hung; Miranda, Felix; Bos, Philip J.

    2003-01-01

    Dynamic holography has been demonstrated as a method for correcting aberrations in space deployable optics, and can also be used to achieve high-resolution beam steering in the same environment. In this paper, we consider some of the factors affecting the efficiency of these devices. Specifically, the effect on the efficiency of a highly collimated beam from the number of discrete phase steps per period is considered for a blazed thin film beam steering grating. The effect of the number of discrete phase steps per period on steering resolution is also considered. We also present some result of Finite-Difference Time-Domain (FDTD) calculations of light propagating through liquid crystal "blazed" gratings. Liquid crystal gratings are shown to spatially modulate both the phase and amplitude of the propagating light.

  11. Compact holographic memory using E - O beam steering

    NASA Technical Reports Server (NTRS)

    Chao, Tien-Hsin; Zhou, Hanying; Reyes, George; Hanan, Jay

    2002-01-01

    An innovative holographic memory system has been developed at JPL for high-density and high speed data storage in a space environment. This system ulitlizes a newly developed electro-optic (E-O) beam steering technology for beam steering to enable high-speed random access memory read/write without moving parts. Recently, a compact CD-sized holographic memory broadboard has been developed and demonstrated for holographic data storage adn retrieval. Detail technical progress will be presented in this paper.

  12. Neutral particle beam sensing and steering

    DOEpatents

    Maier, II, William B.; Cobb, Donald D.; Robiscoe, Richard T.

    1991-01-01

    The direction of a neutral particle beam (NPB) is determined by detecting Ly.alpha. radiation emitted during motional quenching of excited H(2S) atoms in the beam during movement of the atoms through a magnetic field. At least one detector is placed adjacent the beam exit to define an optical axis that intercepts the beam at a viewing angle to include a volume generating a selected number of photons for detection. The detection system includes a lens having an area that is small relative to the NPB area and a pixel array located in the focal plane of the lens. The lens viewing angle and area pixel array are selected to optimize the beam tilt sensitivity. In one embodiment, two detectors are placed coplanar with the beam axis to generate a difference signal that is insensitive to beam variations other than beam tilt.

  13. Image Processing In Laser-Beam-Steering Subsystem

    NASA Technical Reports Server (NTRS)

    Lesh, James R.; Ansari, Homayoon; Chen, Chien-Chung; Russell, Donald W.

    1996-01-01

    Conceptual design of image-processing circuitry developed for proposed tracking apparatus described in "Beam-Steering Subsystem For Laser Communication" (NPO-19069). In proposed system, desired frame rate achieved by "windowed" readout scheme in which only pixels containing and surrounding two spots read out and others skipped without being read. Image data processed rapidly and efficiently to achieve high frequency response.

  14. Suppression of beam steering in an injection-locked laser diode array

    SciTech Connect

    Brewer, L.R. )

    1991-12-09

    Experimental measurements were made to demonstrate that the degree of beam steering in an injection-locked laser diode array is related to the divergence of the master laser beam. For a collimated master laser beam the beam steering was suppressed. The injection-locked laser diode array beam steers with the master laser wavelength because only a portion of the divergent master laser beam satisfies the round trip mode condition.

  15. Oblique incidence effect on steering efficiency of liquid crystal polarization gratings used for optical phased array beam steering amplification

    NASA Astrophysics Data System (ADS)

    Xiangjie, Zhao; Jiazhu, Duan; Dayong, Zhang; Cangli, Liu; Yongquan, Luo

    2016-10-01

    A liquid crystal polarization grating (LCPG) is proposed that amplifies the steering angle of a liquid crystal optical phased array for non-mechanical beam steering, taking advantage of its high steering efficiency under normal incidence. However, oblique incidence may play an important role in the overall steering efficiency. The effect of oblique incidence on steering efficiency of a LCPG was analyzed by numerically solving the extended Jones matrix and considering propagation crosstalk. The results indicate that the outgoing laser beam is amplitude-modulated under the effect of oblique incidence and behaves as a sinusoidal-modulated amplitude grating, which diffracts certain energies to non-blazed orders. Over-oblique incidence may even eliminate the steering effect of the incident beam. The modulation depth of the induced amplitude grating was found to be proportional to the product of sinusoidal value of oblique incidence angle and the LC layer thickness, and inversely proportional to the periodic pitch length of the LCPG. Both in-plane incidence and out-of-plane incidence behave similarly to influence the steering efficiency. Finally, the overall steering efficiency for cascaded LCPGs was analyzed and a difference of up to 11 % steering efficiency can be induced between different LCPG configurations, even without considering the over-oblique incidence effect. Both the modulation depth and final steering efficiency can be optimized by varying the LC birefringence and layer thickness.

  16. Oblique incidence effect on steering efficiency of liquid crystal polarization gratings used for optical phased array beam steering amplification

    NASA Astrophysics Data System (ADS)

    Xiangjie, Zhao; Jiazhu, Duan; Dayong, Zhang; Cangli, Liu; Yongquan, Luo

    2016-07-01

    A liquid crystal polarization grating (LCPG) is proposed that amplifies the steering angle of a liquid crystal optical phased array for non-mechanical beam steering, taking advantage of its high steering efficiency under normal incidence. However, oblique incidence may play an important role in the overall steering efficiency. The effect of oblique incidence on steering efficiency of a LCPG was analyzed by numerically solving the extended Jones matrix and considering propagation crosstalk. The results indicate that the outgoing laser beam is amplitude-modulated under the effect of oblique incidence and behaves as a sinusoidal-modulated amplitude grating, which diffracts certain energies to non-blazed orders. Over-oblique incidence may even eliminate the steering effect of the incident beam. The modulation depth of the induced amplitude grating was found to be proportional to the product of sinusoidal value of oblique incidence angle and the LC layer thickness, and inversely proportional to the periodic pitch length of the LCPG. Both in-plane incidence and out-of-plane incidence behave similarly to influence the steering efficiency. Finally, the overall steering efficiency for cascaded LCPGs was analyzed and a difference of up to 11 % steering efficiency can be induced between different LCPG configurations, even without considering the over-oblique incidence effect. Both the modulation depth and final steering efficiency can be optimized by varying the LC birefringence and layer thickness.

  17. Hybrid silicon free-space source with integrated beam steering

    NASA Astrophysics Data System (ADS)

    Doylend, J. K.; Heck, M. J. R.; Bovington, J. T.; Peters, J. D.; Davenport, M. L.; Coldren, L. A.; Bowers, J. E.

    2013-02-01

    Free-space beam steering using optical phase arrays are desirable as a means of implementing Light Detection and Ranging (LIDAR) and free-space communication links without the need for moving parts, thus alleviating vulnerabilities due to vibrations and inertial forces. Implementing such an approach in silicon photonic integrated circuits is particularly desirable in order to take advantage of established CMOS processing techniques while reducing both device size and packaging complexity. In this work we demonstrate a free-space diode laser together with beam steering implemented on-chip in a silicon photonic circuit. A waveguide phased array, surface gratings, a hybrid III-V/silicon laser and an array of hybrid III/V silicon amplifiers were fabricated on-chip in order to achieve a fully integrated steerable free-space optical source with no external optical inputs, thus eliminating the need for fiber coupling altogether. The chip was fabricated using a modified version of the hybrid silicon process developed at UCSB, with modifications in order to incorporate diodes within the waveguide layer as well as within the III-V gain layer. Beam steering across a 12° field of view with +/-0.3° accuracy and 1.8°x0.6° beam width was achieved, with background peaks suppressed 7 dB relative to the main lobe within the field of view for arbitrarily chosen beam directions.

  18. Agile beam laser radar using computational imaging for robotic perception

    NASA Astrophysics Data System (ADS)

    Powers, Michael A.; Stann, Barry L.; Giza, Mark M.

    2015-05-01

    This paper introduces a new concept that applies computational imaging techniques to laser radar for robotic perception. We observe that nearly all contemporary laser radars for robotic (i.e., autonomous) applications use pixel basis scanning where there is a one-to-one correspondence between world coordinates and the measurements directly produced by the instrument. In such systems this is accomplished through beam scanning and/or the imaging properties of focal-plane optics. While these pixel-basis measurements yield point clouds suitable for straightforward human interpretation, the purpose of robotic perception is the extraction of meaningful features from a scene, making human interpretability and its attendant constraints mostly unnecessary. The imposing size, weight, power and cost of contemporary systems is problematic, and relief from factors that increase these metrics is important to the practicality of robotic systems. We present a system concept free from pixel basis sampling constraints that promotes efficient and adaptable sensing modes. The cornerstone of our approach is agile and arbitrary beam formation that, when combined with a generalized mathematical framework for imaging, is suited to the particular challenges and opportunities of robotic perception systems. Our hardware concept looks toward future systems with optical device technology closely resembling modern electronically-scanned-array radar that may be years away from practicality. We present the design concept and results from a prototype system constructed and tested in a laboratory environment using a combination of developed hardware and surrogate devices for beam formation. The technological status and prognosis for key components in the system is discussed.

  19. Modeling and simulation of the beam steering unit

    NASA Astrophysics Data System (ADS)

    Feng, Jiayun; Li, Xiaoping; He, Xin; Wang, Jinchun

    2015-03-01

    Production lithography is undergoing a technology shift, and the requirements of beam delivery system (BDS) are increasing which also raises the precision requirements of the beam steering units (BSU) in BDS. In essence, the BSU is a two rotational degree of freedom platform. In this paper, a BSU based on 3-RPS flexure parallel mechanism is proposed. By analyzing the relationship between the unit's dimensions and mechanics, a mathematical model is built. Then the BSU with a balance between lower stress of the flexure hinges and higher accuracy of the unit can be got by optimizing the dimensions with the mathematical model. Finally a simulation is conducted to verify the design.

  20. Packaging consideration of two-dimensional polymer-based photonic crystals for laser beam steering

    NASA Astrophysics Data System (ADS)

    Dou, Xinyuan; Chen, Xiaonan; Chen, Maggie Yihong; Wang, Alan Xiaolong; Jiang, Wei; Chen, Ray T.

    2009-02-01

    In this paper, we report the theoretical study of polymer-based photonic crystals for laser beam steering which is based on the superprism effect as well as the experiment fabrication of the two dimensional photonic crystals for the laser beam steering. Superprism effect, the principle for beam steering, was separately studied in details through EFC (Equifrequency Contour) analysis. Polymer based photonic crystals were fabricated through double exposure holographic interference method using SU8-2007. The experiment results were also reported.

  1. Electronically-Controlled Beam-Steering through Vanadium Dioxide Metasurfaces

    NASA Astrophysics Data System (ADS)

    Hashemi, Mohammed Reza M.; Yang, Shang-Hua; Wang, Tongyu; Sepúlveda, Nelson; Jarrahi, Mona

    2016-10-01

    Engineered metamaterials offer unique functionalities for manipulating the spectral and spatial properties of electromagnetic waves in unconventional ways. Here, we report a novel approach for making reconfigurable metasurfaces capable of deflecting electromagnetic waves in an electronically controllable fashion. This is accomplished by tilting the phase front of waves through a two-dimensional array of resonant metasurface unit-cells with electronically-controlled phase-change materials embedded inside. Such metasurfaces can be placed at the output facet of any electromagnetic radiation source to deflect electromagnetic waves at a desired frequency, ranging from millimeter-wave to far-infrared frequencies. Our design does not use any mechanical elements, external light sources, or reflectarrays, creating, for the first time, a highly robust and fully-integrated beam-steering device solution. We demonstrate a proof-of-concept beam-steering metasurface optimized for operation at 100 GHz, offering up to 44° beam deflection in both horizontal and vertical directions. Dynamic control of electromagnetic wave propagation direction through this unique platform could be transformative for various imaging, sensing, and communication applications, among others.

  2. Ka-band MMIC beam steered transmitter array

    NASA Technical Reports Server (NTRS)

    Rascoe, D. L.; Riley, A. L.; Huang, J.; Lubecke, V.; Duffy, L.

    1989-01-01

    A 32-GHz six-element linear transmitter array utilizing monolithic microwave integrated circuit (MMIC) phase shifters and power amplifiers was designed and tested as part of the development of a spacecraft array feed for NASA deep-space communications applications. Measurements of the performance of individual phase shifters, power amplifiers, and microstrip radiators were carried out, and electronic beam steering of the linear array was demonstrated. The switched-line phase shifters were accurate to within 7 percent on average and the power amplifier 1-dB compressed output power varied over 0.3 dB. The array had a beamwidth of 7.5 deg and demonstrated acceptable beam steering over + or - 8 deg. From the results, it can be concluded that this MMIC phased array has adequate beam-scanning capability for use in the two-dimensional array. The areas that need to be improved are the efficiency of the MMIC power amplifier and the insertion loss of the MMIC phase shifter.

  3. Electronically-Controlled Beam-Steering through Vanadium Dioxide Metasurfaces

    PubMed Central

    Hashemi, Mohammed Reza M.; Yang, Shang-Hua; Wang, Tongyu; Sepúlveda, Nelson; Jarrahi, Mona

    2016-01-01

    Engineered metamaterials offer unique functionalities for manipulating the spectral and spatial properties of electromagnetic waves in unconventional ways. Here, we report a novel approach for making reconfigurable metasurfaces capable of deflecting electromagnetic waves in an electronically controllable fashion. This is accomplished by tilting the phase front of waves through a two-dimensional array of resonant metasurface unit-cells with electronically-controlled phase-change materials embedded inside. Such metasurfaces can be placed at the output facet of any electromagnetic radiation source to deflect electromagnetic waves at a desired frequency, ranging from millimeter-wave to far-infrared frequencies. Our design does not use any mechanical elements, external light sources, or reflectarrays, creating, for the first time, a highly robust and fully-integrated beam-steering device solution. We demonstrate a proof-of-concept beam-steering metasurface optimized for operation at 100 GHz, offering up to 44° beam deflection in both horizontal and vertical directions. Dynamic control of electromagnetic wave propagation direction through this unique platform could be transformative for various imaging, sensing, and communication applications, among others. PMID:27739471

  4. Terahertz beam steering and variable focusing using programmable diffraction gratings.

    PubMed

    Monnai, Yasuaki; Altmann, Kristian; Jansen, Christian; Hillmer, Hartmut; Koch, Martin; Shinoda, Hiroyuki

    2013-01-28

    We propose a freely programmable THz diffraction grating based on an electrostatically actuated, computer controlled array of metallic cantilevers. Switching between different grating patterns enables tailoring spatio-temporal profiles of the THz waves. By characterizing the device with spatially resolved THz time domain spectroscopy, we demonstrate beam steering for a wide frequency band extending from 0.15 THz to 0.9 THz. The steerable range at 0.3 THz exceeds 40°. Focusing is also demonstrated by programming a chirped grating. The proposed approach could be employed to mimic arbitrary diffraction optics, enabling highly integrated and extremely flexible systems indispensable for THz stand-off imaging and communications.

  5. Bottom profiling by correlating beam-steered noise sequences.

    PubMed

    Harrison, Chris H; Siderius, Martin

    2008-03-01

    It has already been established that by cross-correlating ambient noise time series received on the upward and downward steered beams of a drifting vertical array one can obtain a subbottom layer profile. Strictly, the time differential of the cross correlation is the impulse response of the seabed. Here it is shown theoretically and by simulation that completely uncorrelated surface noise results in a layer profile with predictable amplitudes proportional to those of an equivalent echo sounder at the same depth as the array. The phenomenon is simulated by representing the sound sources as multiple random time sequences emitted from random locations in a horizontal plane above a vertical array and then accounting for the travel times of the direct and bottom reflected paths. A well-defined correlation spike is seen at the depth corresponding to the bottom reflection despite the fact that the sound sources contain no structure whatsoever. The effects of using simultaneously steered upward and downward conical beams with a tilted or faceted seabed and multiple layers are also investigated by simulation. Experimental profiles are obtained using two different vertical arrays in smooth and rough bottom sites in the Mediterranean. Correlation peak amplitudes follow the theory and simulations closely. PMID:18345817

  6. A prototype high-speed optically-steered X-band phased array antenna.

    PubMed

    Wu, Pengfei; Tang, Suning; Raible, Daniel E

    2013-12-30

    We develop a prototype of optically-steered X-band phased array antenna with capabilities of multi-band and multi-beam operations. It exploits high-speed wavelength tunable lasers for optical true-time delays over a dispersive optical fiber link, enabling agile, broadband and vibration-free RF beam steering with large angle.

  7. Ultra-thin anisotropic metasurface for polarized beam splitting and reflected beam steering applications

    NASA Astrophysics Data System (ADS)

    Guo, Wenlong; Wang, Guangming; Li, Tangjing; Li, Haipeng; Zhuang, Yaqiang; Hou, Haisheng

    2016-10-01

    In this paper, we propose a polarization beam splitter utilizing an ultra-thin anisotropic metasurface. The proposed anisotropic element is composed of triple-layered rectangular patches spaced with double-layered dielectric isolators. By tailoring the metallic patches, the cell is capable of transmitting x-polarized waves efficiently and reflecting y-polarized beams with almost 100% efficiency at 15 GHz. In addition to this, the reflected phases can be modulated by adjusting the size of the element, which contributes to beam steering in reflection mode. By assigning gradient phases on the metasurface, the constructed sample has the ability to refract x-polarized waves normally and reflect y-polarized beams anomalously. For verification, a sample with a size of 240 × 240 mm2 is fabricated and measured. Consistent numerical and experimental results have both validated the efficiently anomalous reflection for y-polarized waves and normal refraction for x-polarized beams operating from 14.6-15.4 GHz. Furthermore, the proposed sample has a thickness of 0.1λ at 15 GHz, which provides a promising approach for steering and splitting beams in a compact size.

  8. Application of multiple-hypothesis tracking to agile beam radar tracking

    NASA Astrophysics Data System (ADS)

    Popoli, Robert F.; Blackman, Samuel S.; Busch, M. T.

    1996-05-01

    This paper describes methods that have been developed for using multiple hypothesis tracking (MHT) for an agile beam radar in the presence of range gate pull off (RGPO) electronic countermeasures (ECM). The paper shows how the agile beam radar allocation logic can be extended to include uncertainty in target position due to data association uncertainty. It also shows how the MHT track score can be modified to reflect target offset from the commanded radar antenna position and how measured SNR is included in the track score. Results from the second Benchmark tracking study are presented. These results show MHT-based allocation to ge highly efficient. The results also show that the system satisfies stringent track maintenance requirements in the presence of RGPO and coincident target maneuvers.

  9. Grating enhanced MOEMS: a novel class of beam steering devices

    NASA Astrophysics Data System (ADS)

    Pradelles, J.; Garrigues, M.; Leclercq, J. L.; Viktorovitch, P.

    2005-07-01

    In this paper we describe a new class of tunable interferometric MOEMS devices able to perform tunable wavelength selective beam steering. These GEMOEMS (Grating Enhanced Micro Opto Electro Mechanical Systems) devices comprise a diffraction grating etched on top of a selective and tunable vertical interferometric MOEMS filter. The underlying filter reflects the transmitted orders with controllable amplitude and phase so that they interfere with the reflected orders and modulate the diffraction efficiency distribution into these reflected orders. Our first demonstrator is a 1X2 optical switch designed for operation over the C-band (1530-1560 nm). The diffraction efficiency in the reflected orders is controlled by changing the distance from the grating to a Bragg mirror via an electrostatic actuation of the suspended grating membrane. The devices are fabricated using a multiple InP-air-gap MOEMS technology based on the sacrificial etching of an InP / InGaAs stack. The grating is realized using an electron-beam lithography step. The simulated performances on the C-band show low insertion loss (less than 0.3dB), low ripple (0.15dB), reasonable cross-talk (-15dB), and an estimated switching time around 10μs. These characteristics make such an optical switch a solid contender of a rotating mirror, with the advantage of a much faster response. In this presentation, we introduce the general physical principles of GEMOEMS and describe the design, simulation, fabrication and preliminary experimental results for a simplified 1x2 optical switch. We also propose other prospective devices such as add-drop filters.

  10. Practicality of electronic beam steering for MST/ST radars, part 6.2A

    NASA Technical Reports Server (NTRS)

    Clark, W. L.; Green, J. L.

    1984-01-01

    Electronic beam steering is described as complex and expensive. The Sunset implementation of electronic steering is described, and it is demonstrated that such systems are cost effective, versatile, and no more complex than fixed beam alternatives, provided three or more beams are needed. The problem of determining accurate meteorological wind components in the presence of spatial variation is considered. A cost comparison of steerable and fixed systems allowing solution of this problem is given. The concepts and relations involved in phase steering are given, followed by the description of the Sunset ST radar steering system. The implications are discussed, references to the competing SAD method are provided, and a recommendation concerning the design of the future Doppler ST/MST systems is made.

  11. Simulation of two-dimensional target motion based on a liquid crystal beam steering method

    NASA Astrophysics Data System (ADS)

    Lin, Yixiang; Ai, Yong; Shan, Xin; Liu, Min

    2015-05-01

    A simulation platform is established for target motion using a liquid crystal (LC) spatial light modulator as a nonmechanical beam steering control device. By controlling the period and orientation of the phase grating generated by the spatial light modulator, the platform realizes two-dimensional (2-D) beam steering using a single LC device. The zenith and azimuth angle range from 0 deg to 2.89 deg and from 0 deg to 360 deg, respectively, with control resolution of 0.0226 deg and 0.0300 deg, respectively. The response time of the beam steering is always less than 0.04 s, irrespective of steering angle. Three typical aircraft tracks are imitated to evaluate the performance of the simulation platform. The correlation coefficients between the theoretical and simulated motions are larger than 0.9822. Results show that it is highly feasible to realize 2-D target motion simulation using the LC spatial light modulator.

  12. Two dimensional thermo-optic beam steering using a silicon photonic optical phased array

    NASA Astrophysics Data System (ADS)

    Mahon, Rita; Preussner, Marcel W.; Rabinovich, William S.; Goetz, Peter G.; Kozak, Dmitry A.; Ferraro, Mike S.; Murphy, James L.

    2016-03-01

    Components for free space optical communication terminals such as lasers, amplifiers, and receivers have all seen substantial reduction in both size and power consumption over the past several decades. However, pointing systems, such as fast steering mirrors and gimbals, have remained large, slow and power-hungry. Optical phased arrays provide a possible solution for non-mechanical beam steering devices that can be compact and lower in power. Silicon photonics is a promising technology for phased arrays because it has the potential to scale to many elements and may be compatible with CMOS technology thereby enabling batch fabrication. For most free space optical communication applications, two-dimensional beam steering is needed. To date, silicon photonic phased arrays have achieved two-dimensional steering by combining thermo-optic steering, in-plane, with wavelength tuning by means of an output grating to give angular tuning, out-of-plane. While this architecture might work for certain static communication links, it would be difficult to implement for moving platforms. Other approaches have required N2 controls for an NxN element phased array, which leads to complexity. Hence, in this work we demonstrate steering using the thermo-optic effect for both dimensions with a simplified steering mechanism requiring only two control signals, one for each steering dimension.

  13. Demonstration of large-angle nonmechanical laser beam steering based on LC polymer polarization gratings

    NASA Astrophysics Data System (ADS)

    Kim, Jihwan; Miskiewicz, Matthew N.; Serati, Steve; Escuti, Michael J.

    2011-05-01

    Polarization gratings (PGs) as polarization sensitive diffractive optical elements work in broadband (UV to Mid- IR) with nearly 100% diffraction efficiency. We have introduced and utilized the PGs in different types of beam steering modules presented in our previous papers. Here, we describe and demonstrate a nonmechanical beam steering device based on passive gratings, liquid crystal (LC) polymer PGs. The device covers a large-angle Field-Of-Regard (FOR) with high efficiency, and is based on a stack of alternating LC half-wave plates and LC polymer PGs. The half-wave plates are switchable and are used to select the handedness of the circularly polarized input beam. The polymer PGs diffract the input beam to either of the first diffraction orders based on the circular handedness of the beam previously selected. When compared with conventional beam steering methods based on active gratings (ternary and quasi-ternary designs), this technique is experimentally able to steer an equivalent number of angles with similar efficiency, but fewer LC cells, and hence, fewer transparent electrodes and lower absorption. We successfully demonstrate the ability to steer 80° FOR with roughly 2.6° resolution at 1064 nm wavelength.

  14. Continuous Beam Steering From A Segmented Liquid Crystal Optical Phased Array

    NASA Technical Reports Server (NTRS)

    Pouch, John; Nguyen, Hung; Miranda, Felix; Titus, Charles M.; Bos, Philip J.

    2002-01-01

    Optical communications to and from deep space probes will require beams possessing divergence on the order of a microradian, and must be steered with sub-microradian precision. Segmented liquid crystal spatial phase modulators, a type of optical phased array, are considered for this ultra-high resolution beam steering. It is shown here that in an ideal device of this type, there are ultimately no restrictions on the angular resolution. Computer simulations are used to obtain that result, and to analyze the influence of beam truncation and substrate flatness on the performance of this type of device.

  15. Continuous Beam Steering From a Segmented Liquid Crystal Optical Phased Array

    NASA Technical Reports Server (NTRS)

    Titus, Charles M.; Pouch, John; Nguyen, Hung; Miranda, Felix; Bos, Philip J.

    2002-01-01

    Optical communications to and from deep space probes will require beams possessing divergence on the order of a microradian, and must be steered with sub-microradian precision. Segmented liquid crystal spatial phase modulators, a type of optical phased array, are considered for this ultra-high resolution beam steering. It is shown here that in an ideal device of this type, there are ultimately no restrictions on the angular resolution. Computer simulations are used to obtain that result, and to analyze the influence of beam truncation and substrate flatness on the performance of this type of device.

  16. Switchable beam steering with zenithal bistable liquid-crystal blazed gratings.

    PubMed

    Zografopoulos, Dimitrios C; Kriezis, Emmanouil E

    2014-10-15

    Switchable beam steerers based on zenithal bistable liquid crystal (LC) gratings are designed and theoretically investigated. The nematic orientation profiles and the optical transmittance properties of the gratings are rigorously calculated, respectively, via a tensorial formulation of the Landau-de Gennes theory and the full-wave finite-element-method. By proper design of the grating geometry, beam steering with high diffraction efficiency is demonstrated between the two stable LC states. The tolerance of the device performance with respect to material parameters is assessed, evidencing spectral operation windows of more than 50 nm in the visible for a beam steering efficiency higher than 90%. PMID:25361099

  17. A prototype of a beam steering assistant tool for accelerator operations

    SciTech Connect

    M. Bickley; P. Chevtsov

    2006-10-24

    The CEBAF accelerator provides nuclear physics experiments at Jefferson Lab with high quality electron beams. Three experimental end stations can simultaneously receive the beams with different energies and intensities. For each operational mode, the accelerator setup procedures are complicated and require very careful checking of beam spot sizes and positions on multiple beam viewers. To simplify these procedures and make them reproducible, a beam steering assistant GUI tool has been created. The tool is implemented as a multi-window control screen. The screen has an interactive graphical object window, which is an overlay on top of a digitized live video image from a beam viewer. It allows a user to easily create and edit any graphical objects consisting of text, ellipses, and lines, right above the live beam viewer image and then save them in a file that is called a beam steering template. The template can show, for example, the area within which the beam must always be on the viewer. Later, this template can be loaded in the interactive graphical object window to help accelerator operators steer the beam to the specified area on the viewer.

  18. Steering, splitting, and cloning of an optical beam in a coherently driven Raman gain system

    NASA Astrophysics Data System (ADS)

    Verma, Onkar N.; Dey, Tarak N.

    2015-01-01

    We propose an all-optical antiwaveguide mechanism for steering, splitting, and cloning of an optical beam without diffraction. We use a spatially inhomogeneous pump beam to create an antiwaveguide structure in a Doppler broadened N -type four-level Raman gain medium for a copropagating weak probe beam. We show that a transverse modulated index of refraction and gain due to the spatially dependent pump beam hold the keys to steering, splitting, and cloning of an optical beam. We have also shown that an additional control field permits the propagation of an optical beam through an otherwise gain medium without diffraction and instability. We further discuss how finesse of the cloned images can be increased by changing the detuning of the control field. We arrive at similar results by using homogeneously broadened gain media at higher density.

  19. Primary Beam Steering Due To Field Leakage From Superconducting SHMS Magnets

    NASA Astrophysics Data System (ADS)

    Moore, Michael; Covrig, Silviu; Carlini, Roger; Waidyawansa, Buddhini; Benesch, Jay

    2014-03-01

    The Super High Momentum Spectrometer (SHMS) was designed for the 12 GeV/c physics program in Hall C at Thomas Jefferson National Accelerator (JLab). At JLab an electron beam impinges on a fixed target and scattered particles are analyzed with magnetic spectrometers. The SHMS angular acceptance is 5 .5° <= θ <=40° . When positioned at θ = 5 .5° and full field strength the external fields from the magnets are large enough to steer the unscattered primary beam away from the beam dump window located 51.8 m from the target. The effects of these magnetic fields on the primary beam line downstream of the target are studied using Opera 3-D and TOSCA. A solution is presented that uses passive elements to shape these fields and assure that the primary beam is steered onto the beam dump window.

  20. On-chip silicon optical phased array for two-dimensional beam steering.

    PubMed

    Kwong, David; Hosseini, Amir; Covey, John; Zhang, Yang; Xu, Xiaochuan; Subbaraman, Harish; Chen, Ray T

    2014-02-15

    A 16-element optical phased array integrated on chip is presented for achieving two-dimensional (2D) optical beam steering. The device is fabricated on the silicon-on-insulator platform with a 250 nm silicon device layer. Steering is achieved via a combination of wavelength tuning and thermo-optic phase shifting with a switching power of P(π)=20  mW per channel. Using a silicon waveguide grating with a polycrystalline silicon overlay enables narrow far field beam widths while mitigating the precise etching needed for conventional shallow etch gratings. Using this system, 2D steering across a 20°×15° field of view is achieved with a sidelobe level better than 10 dB and with beam widths of 1.2°×0.5°.

  1. Active terahertz beam steering by photo-generated graded index gratings in thin semiconductor films.

    PubMed

    Steinbusch, T P; Tyagi, H K; Schaafsma, M C; Georgiou, G; Gómez Rivas, J

    2014-11-01

    We demonstrate active beam steering of terahertz radiation using a photo-excited thin layer of gallium arsenide. A constant gradient of phase discontinuity along the interface is introduced by an spatially inhomogeneous density of free charge carriers that are photo-generated in the GaAs with an optical pump. The optical pump has been spatially modulated to form the shape of a planar blazed grating. The phase gradient leads to an asymmetry between the +1 and -1 transmission diffracted orders of more than a factor two. Optimization of the grating structure can lead to an asymmetry of more than one order of magnitude. Similar to metasurfaces made of plasmonic antennas, the photo-generated grating is a planar structure that can achieve large beam steering efficiency. Moreover, the photo-generation of such structures provides a platform for active THz beam steering. PMID:25401807

  2. Improved beam steering accuracy of a single beam with a 1D phase-only spatial light modulator.

    PubMed

    Engström, David; Bengtsson, Jörgen; Eriksson, Emma; Goksör, Mattias

    2008-10-27

    The limited number of pixels and their quantized phase modulation values limit the positioning accuracy when a phase-only one dimensional spatial light modulator (SLM) is used for beam steering. Applying the straightforward recipe for finding the optimal setting of the SLM pixels, based on individually optimizing the field contribution from each pixel to the field in the steering position, the inaccuracy can be a significant fraction of the diffraction limited spot size. This is especially true in the vicinity of certain steering angles where precise positioning is particularly difficult. However, by including in the optimization of the SLM setting an extra degree of freedom, we show that the steering accuracy can be drastically improved by a factor proportional to the number of pixels in the SLM. The extra degree of freedom is a global phase offset of all the SLM pixels which takes on a different value for each steering angle. Beam steering experiments were performed with the SLM being set both according to the conventional and the new recipe, and the results were in very good agreement with the theoretical predictions.

  3. Liquid Crystal-Based Beam Steering Device Development for NASA Applications

    NASA Technical Reports Server (NTRS)

    Pouch, John; Nguyen, Hung; Miranda, Felix; Bos, Philip; Lavrentovich, Oleg; Wang, Xinghua

    2004-01-01

    The NASA Computing, Information and Communications Technology (CICT) Program is supporting the development of liquid crystal-based beam steering devices. The device would use inexpensive, light-weight, optical components, and it would have the following capabilities: electronic beam scanning to angles above 1 milliradian, and submicroradian beam pointing accuracy. In order to correct for the imperfections resulting from the space-deployable optics, the technique of wave-front correction would be implemented. Hence, the output beam quality would be maintained. The potential applications could include satellite tracking, near-Earth inter-satellite communications, deep-space communications, and optical phased array systems. The status of the beam steering device development based on the liquid crystal technology and its relationship to prospective NASA mission scenarios will be described.

  4. Wide-angle nonmechanical beam steering using thin liquid crystal polarization gratings

    NASA Astrophysics Data System (ADS)

    Kim, Jihwan; Oh, Chulwoo; Escuti, Michael J.; Hosting, Lance; Serati, Steve

    2008-08-01

    We introduce and demonstrate a compact, nonmechanical beam steering device based on liquid Crystal (LC) Polarization Gratings (PGs). Directional control of collimated light is essential for free-space optical communications, remote sensing, and related technologies. However, current beam steering methods often require moving parts, or are limited to small angle operation, offer low optical throughput, and are constrained by size and weight. We employ multiple layers of LCPGs to achieve wide-angle (> +/-40°), coarse beam steering of 1550 nm light in a remarkably thin package. LCPGs can be made in switchable or polymer materials, and possess a continuous periodic birefringence profile, that renders several compelling properties (experimentally realized): ~ 100% experimental diffraction efficiency into a single order, high polarization sensitivity, and very low scattering. Light may be controlled within and between the zero- and first-diffraction orders by the handedness of the incident light and potentially by voltage applied to the PG itself. We implement a coarse steering device with several LCPGs matched with active halfwave LC variable retarders. Here, we present the preliminary experimental results and discuss the unique capability of this wide-angle steering.

  5. Primary beam steering due to field leakage from superconducting SHMS magnets

    NASA Astrophysics Data System (ADS)

    Moore, M. H.; Waidyawansa, B. P.; Covrig, S.; Carlini, R.; Benesch, J.

    2014-11-01

    Simulations of the magnetic fields from the Super High Momentum Spectrometer in Hall C at Thomas Jefferson National Accelerator Facility show significant field leakage into the region of the primary beam line between the target and the beam dump. Without mitigation, these remnant fields will steer the unscattered beam enough to limit beam operations at small scattering angles. Presented here are magnetic field simulations of the spectrometer magnets and a solution using optimal placement of a minimal amount of shielding iron around the beam line.

  6. Primary beam steering due to field leakage from superconducting SHMS magnets

    DOE PAGES

    Moore, Michael H.; Waidyawansa, Buddhini P.; Covrig, Silviu; Carlini, Roger; Benesch, Jay

    2014-11-05

    In this study, simulations of the magnetic fields from the Super High Momentum Spectrometer in Hall C at Thomas Jefferson National Accelerator Facility show significant field leakage into the region of the primary beam line between the target and the beam dump. Without mitigation, these remnant fields will steer the unscattered beam enough to limit beam operations at small scattering angles. Presented here are magnetic field simulations of the spectrometer magnets and a solution using optimal placement of a minimal amount of shielding iron around the beam line.

  7. Terahertz beam steering and frequency tuning by using the spatial dispersion of ultrafast laser pulses.

    PubMed

    Maki, Ken-ichiro; Otani, Chiko

    2008-07-01

    We demonstrate a terahertz (THz) beam steering method using difference frequency generation that is based on the principle of phased array antennas. A strip-line photoconductive antenna was illuminated by two spatially dispersed beams produced from an ultrafast laser. THz radiation with a bandwidth of 65 GHz was generated from the overlapping area of the two beams, between which the frequency difference was approximately constant. We confirmed that the THz beam can be steered by tilting one of the incident pump beams so as to change their relative phase relation. The steering range of the THz beam was 29 degrees when the angle between the incident pump beams was only varied within a range of 0.155 degrees, that is, 187 times less. In addition, by laterally shifting one of the pump beams, the frequency of the THz radiation could be tuned from 0.3 to 1.7 THz. This technique can be applied to high-speed terahertz imaging and spectroscopy systems. PMID:18607423

  8. Demonstration of beam steering via dipole-coupled plasmonic spiral antenna.

    PubMed

    Rui, Guanghao; Abeysinghe, Don C; Nelson, Robert L; Zhan, Qiwen

    2013-01-01

    Optical antennas have been utilized to tailor the emission properties of nanoscale emitters in terms of the intensity, directivity and polarization. In this letter, we further explore the capability of beam steering via the use a spiral plasmonic structure as a transmitting antenna. According to both numerical simulation and experimental observations, the beaming direction can be steered through introducing a displacement of the feeding point to the spiral antenna from the geometrical center. For a 3-turn Archimedes' spiral antenna, experimental results show that steering angles of 3° and 7° are obtainable when the excitation location is transversally shifted from the center by a displacement of 200 nm and 500 nm, respectively. Furthermore, the emitted photons carry spin angular momentum determined by the chirality of the spiral optical antenna. A steerable nanoscale spin photon source may find important applications in single molecule sensing, quantum optical information processing and integrated photonic circuits. PMID:23868718

  9. Demonstration of beam steering via dipole-coupled plasmonic spiral antenna

    PubMed Central

    Rui, Guanghao; Abeysinghe, Don C.; Nelson, Robert L.; Zhan, Qiwen

    2013-01-01

    Optical antennas have been utilized to tailor the emission properties of nanoscale emitters in terms of the intensity, directivity and polarization. In this letter, we further explore the capability of beam steering via the use a spiral plasmonic structure as a transmitting antenna. According to both numerical simulation and experimental observations, the beaming direction can be steered through introducing a displacement of the feeding point to the spiral antenna from the geometrical center. For a 3-turn Archimedes' spiral antenna, experimental results show that steering angles of 3° and 7° are obtainable when the excitation location is transversally shifted from the center by a displacement of 200 nm and 500 nm, respectively. Furthermore, the emitted photons carry spin angular momentum determined by the chirality of the spiral optical antenna. A steerable nanoscale spin photon source may find important applications in single molecule sensing, quantum optical information processing and integrated photonic circuits. PMID:23868718

  10. SU-E-T-149: Electron Beam Profile Differences Between Elekta MLCi2 and Elekta Agility Treatment Heads

    SciTech Connect

    Wu, C; Hatcher, C

    2014-06-01

    Purpose: To report and investigate observed differences in electron beam profiles at various energies/applicators between Elekta MLCi2 and Agility treatment head on Elekta Infinity LINAC Methods: When we upgraded from MLCi2 to Agility on one of our Elekta Infinity LINAC's, electron beam PDDs and profiles were acquired for comparison purpose. All clinical electron energies (6/9/12/15/12/18 MeV) and electron applicators (6/10/14/20/25 square) were included in measurement. PDDs were acquired at 100 SSD in water (PTW MP3 water tank) with a plane-parallel ion chamber (PTW Roos). X and Y Profiles were acquired using IC Profiler (Sun Nuclear Corp.) at 1cm and maximum PDD depths (water equivalent). Results: All PDD curves match very well between MLCi2 and Agility treatment head. However, some significant differences on electron profiles were found. On Agility, even after increasing the default auto-tracking offset values for backup diaphragms in Y and MLC in X by 2.8 cm (the maximum allowed change is 3.0 cm), electron profiles still have rounder shoulders comparing to corresponding MLCi2 profiles. This difference is significantly more pronounced at larger applicators (20 and 25 square), for all electron energies. Conclusion: The significant design change between MLCi2 and Agility beam limiting device seems to affect exit electron beam profiles. In IEC1217 X direction, the main change on Agility is the removal of the original MLCi2 X backup diaphragms and replacing it with MLC leaves; In Y direction, the main change is the radius and materials on Y backup diaphragms.

  11. Coupled Oscillator Based Agile Beam Transmitters and Receivers: A Review of Work at JPL

    NASA Technical Reports Server (NTRS)

    Pogorzelski, Ronald J.

    2006-01-01

    This is a review of the work done at Caltech's Jet Propulsion Laboratory during the past decade on development of the coupled oscillator technology in phased array applications to spacecraft telecommunications. First, some historical background is provided to set the work in context. However, this is by no means intended to be a comprehensive review of all work in this area. Rather, the focus is on the JPL contribution with some mention of other work which provided either insight or motivation. In the mid 1990's, R. A. York, and collaborators proposed that an array of mutually injection locked electronic oscillators could provide appropriately phased signals to the radiating elements of an array antenna such that the radiated beam could be steered merely by tuning the end or perimeter oscillators of the array. York, et al. also proposed a receiving system based on such oscillator arrays in which the oscillators provide properly phased local oscillator signals to be mixed with the signals received by the array elements to remove the phase due to angle of arrival of the incident wave. These concepts were viewed as a promising simplification of the beam steering control system that could result in significant cost, mass, and prime power reduction and were therefore attractive for possible space application.

  12. Light steering of Air-Gaussian beam in Nonlocal Nonlinear Medium

    NASA Astrophysics Data System (ADS)

    Chen, Ran; Zhang, Xiaping

    2016-07-01

    With a nonlocal model, we investigate the propagation dynamics of a single Airy-Gaussian (AiG) beam and their interaction in one-dimensional condition by means of direct numerical simulations. With the split-step Fourier method, numerical results show that nonlocality can support periodic intensity distribution of AiG beams leading to the formation of stable bound states. Espesically, by tuning the phase difference between the two beams, we can steer the centre of the bound AiG beams in nonlocal nonlinear media.

  13. On-ground calibration of AGILE-GRID with a photon beam: results and lessons for the future

    NASA Astrophysics Data System (ADS)

    Cattaneo, P. W.; Rappoldi, A.

    2013-06-01

    On the AGILE satellite, there is the Gamma Ray Imaging Detector (GRID) consisting of a Silicon Tracker (ST), a Cesium Iodide Mini-Calorimeter and an Anti-Coincidence system of plastic scintillator bars. The ST needs a calibration with a γ-ray beam to validate the simulation used to calculate the detector response versus the energy and the direction of the γ rays. A tagged γ-ray beam line was designed at the Beam Test Facility of the Laboratori Nazionali of Frascati, generated by an electron beam through bremsstrahlung in a position-sensitive target. The γ-ray energy is deduced by the difference with the post-bremsstrahlung electron energy [P. W. Cattaneo, et al., Characterization of a tagged γ-ray beam line at the daΦne beam test facility, Nucl. Instr. and Meth. A 674 (2012) 55-66; P. W. Cattaneo, et al., First results about on-ground calibration of the silicon tracker for the agile satellite, Nucl. Instr. and Meth. A 630(1) (2011) 251-257.]. The electron energy is measured by a spectrometer consisting of a dipole magnet and an array of position sensitive silicon strip detectors, the Photon Tagging System (PTS). In this paper the setup and the calibration of AGILE performed in 2005 are described.

  14. A compact beam focusing and steering element using quadrupoles with independently excited poles

    NASA Astrophysics Data System (ADS)

    Grime, Geoffrey W.

    2013-07-01

    Beam steering elements for accelerator beam transport are conventionally and conveniently incorporated into beamlines by fitting magnetic dipole elements around the vacuum tube of the line. Two steerers in each plane (X and Y) together with a quadrupole doublet constitute a module providing full control of the direction, position and focus of the beam. In some installations however, there may be insufficient space on the beamline to mount separate steerer elements. To provide steering capabilities in such a situation we have used a magnetic quadrupole doublet with the coils of each pole independently excited to synthesise the desired combination of quadrupole, horizontal dipole and vertical dipole fields. This paper describes the quadrupole steerer and its multichannel power supply and presents calculated magnetic field distributions together with raytracing simulation of its performance.

  15. Free-space transmission with passive 2D beam steering for multi-gigabit-per-second per-beam indoor optical wireless networks.

    PubMed

    Oh, Chin Wan; Cao, Zizheng; Tangdiongga, Eduward; Koonen, Ton

    2016-08-22

    In order to circumvent radio spectrum congestion, we propose an innovative system which can provide multiple infrared optical wireless beams simultaneously where each beam supports multi-gigabit-per-second communication. Scalable two-dimensional beam steering by means of wavelength tuning is proposed. A passive beam-steering module constructed with cascaded reflection gratings is designed for simultaneous multi-user coverage. We experimentally characterized the beam-steered system and thoroughly evaluated the performance of steered channels using the spectrally efficient and robust discrete multitone modulation in a bandwidth-limited system deploying 10 GHz telecom transceivers. This study reports the achievement of at least 37 Gbps free-space transmission per beam over a distance of up to 2 m over 5.61° × 12.66° scanning angles. PMID:27557201

  16. Beam steering and deflecting device using step-based micro-blazed grating

    NASA Astrophysics Data System (ADS)

    Yang, Junbo; Su, Xianyu; Xu, Ping; Gu, Zheng

    2008-08-01

    The rapidly evolving demands of optical communications and optical switching systems have created a new market for high capacity all-optical beam steering and deflecting techniques. One technology potentially capable of realizing such systems uses the multistep micro-blazed grating optical beam deflectors based on binary and multiple-phase modulation methods. The micro-optical element has been fabricated by introducing very large scale integration (VLSI), stepping photolithography and reactive ion etching (RIE), which can realize beam steering, deflecting, splitting, and switching in free space, and its diffraction properties are determined by the blazed-grating parameters, such as the number of steps, grating depth, grating period, as well as blazed profile. The theoretical analysis and primarily experimental result show that this phase-type element has the advantages of high diffractive efficiency, low cross talk, small feature size, and high reliability due to nonmechanical beam steering without any moving parts. Hence it is ideally suited to applications in optical communication and optical interconnection network.

  17. Multiple beam communicating satellites with remote beam steering and beam shaping

    NASA Technical Reports Server (NTRS)

    Sielman, P. F.; Schwartz, L.; Noji, T. T.

    1974-01-01

    Multiple beam phased arrays are shown to enhance the performance of several anticipated geostationary communications satellite programs because of the greater efficiency and flexibility of the phased array. It is shown that the efficiency of arrays can be significantly greater than corresponding multiple feed dishes and that the problems of crossover loss and performance degradation with parts failures are thereby avoided. On an open loop basis, it is shown that a multiple beam array can provide higher EIRP over a coverage area. On a closed loop basis, it is shown that an adaptive array can provide nulling of unwanted signals while simultaneously providing gain in the direction of a desired signal.

  18. Vertical split-ring resonator based anomalous beam steering with high extinction ratio

    PubMed Central

    Hsu, Wei-Lun; Wu, Pin Chieh; Chen, Jia-Wern; Chen, Ting-Yu; Cheng, Bo Han; Chen, Wei Ting; Huang, Yao-Wei; Liao, Chun Yen; Sun, Greg; Tsai, Din Ping

    2015-01-01

    Metasurfaces created artificially with metal nanostructures that are patterned on surfaces of different media have shown to possess “unusual” abilities to manipulate light. Limited by nanofabrication difficulties, so far most reported works have been based on 2D metal structures. We have recently developed an advanced e-beam process that allowed for the deposition of 3D nanostructures, namely vertical split-ring resonators (VSRRs), which opens up another degree of freedom in the metasurface design. Here we explore the functionality of beam steering with phase modulation by tuning only the vertical dimension of the VSRRs and show that anomalous steering reflection of a wide range of angles can be accomplished with high extinction ratio using the finite-difference-time-domain simulation. We also demonstrate that metasurfaces made of 3D VSRRs can be made with roughly half of the footprint compared to that of 2D nano-rods, enabling high density integration of metal nanostructures. PMID:26054048

  19. Design and development of an electrically-controlled beam steering mirror for microwave tomography

    SciTech Connect

    Tayebi, A.; Tang, J.; Paladhi, P. Roy; Udpa, L.; Udpa, S.

    2015-03-31

    Microwave tomography has gained significant attention due to its reliability and unhazardous nature in the fields of NDE and medical industry. A new microwave tomography system is presented in this paper, which significantly reduces the design and operational complexities of traditional microwave imaging systems. The major component of the proposed system is a reconfigurable reflectarray antenna which is used for beam steering in order to generate projections from multiple angles. The design, modeling and fabrication of the building block of the antenna, a tunable unit cell, are discussed in this paper. The unit cell is capable of dynamically altering the phase of the reflected field which results in beam steering ability of the reflectarray antenna. A tomographically reconstructed image of a dielectric sample using this new microwave tomography system is presented in this work.

  20. A microwave tomography system using a tunable mirror for beam steering

    SciTech Connect

    Tayebi, A.; Tang, J.; Paladhi, P. Roy; Udpa, L.; Udpa, S.

    2014-02-18

    Microwave tomography is a fast-growing technique in the fields of NDE and medical industry. This paper presents a new microwave tomography system which reduces the complexities of conventional microwave imaging systems by utilizing a reconfigurable mirror, a tunable reflectarray antenna. In order to build a tunable reflectarray with beam steering capabilities, the unit cell characteristics should dynamically alter. Modelling and experimental results of a single unit cell are presented in this work.

  1. 2D Traveling Wave Array Employing a Trapezoidal Dielectric Wedge for Beam Steering

    NASA Technical Reports Server (NTRS)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranada, Felix A.

    2014-01-01

    This presentation addresses the progress made so far in the development of an antenna array with reconfigurable transmission line feeds connecting each element in series. In particular, 2D traveling wave array employing trapezoidal Dielectric Wedge for Beam Steering will be discussed. The presentation includes current status of the effort and suggested future work. The work is being done as part of the NASA Office of the Chief Technologist's Space Technology Research Fellowship (NSTRF).

  2. Voltage calibration of dual-frequency liquid crystal devices for infrared beam steering applications

    NASA Astrophysics Data System (ADS)

    Mahajan, Milind; Wen, Bing; Bhupathy, Vinay; Taber, Donald; Winker, Bruce

    2005-08-01

    This paper addresses the use of liquid crystal devices for electro-optic infrared laser beam steering, such as liquid crystal optical phased arrays (OPAs) and digital beam deflectors (DBDs). In these devices, voltages are synchronously applied to different liquid crystal pixels to steer light, either by diffraction and/or refraction using birefringent prisms. Dual frequency liquid crystals provide an order of magnitude higher speed as compared to conventional nematic liquid crystals, at the cost of more complex addressing algorithms and control circuits. In order to optimize the optical performance of a liquid crystal device, the control voltages must be calibrated. This procedure involves adjustment of the control voltages while monitoring the optical efficiency, and must be done for both steady-state phase levels as well as transitions between phase levels. Manual voltage calibration is unrealistically time consuming for multi-channel beam steering devices. Computer based calibration algorithms for dual frequency liquid crystal devices are discussed, and results are presented for both steady state and dynamic voltage calibration procedures.

  3. Experimental validation of a transformation optics based lens for beam steering

    SciTech Connect

    Yi, Jianjia; Burokur, Shah Nawaz Lustrac, André de

    2015-10-12

    A transformation optics based lens for beam control is experimentally realized and measured at microwave frequencies. Laplace's equation is adopted to construct the mapping between the virtual and physical spaces. The metamaterial-based lens prototype is designed using electric LC resonators. A planar microstrip antenna source is used as transverse electric polarized wave launcher for the lens. Both the far field radiation patterns and the near-field distributions have been measured to experimentally demonstrate the beam steering properties. Measurements agree quantitatively and qualitatively with numerical simulations, and a non-narrow frequency bandwidth operation is observed.

  4. Electrostatic steering and beamlet aiming in large neutral beam injectors

    NASA Astrophysics Data System (ADS)

    Veltri, P.; Cavenago, M.; Chitarin, G.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P.

    2015-04-01

    Neutral beam injection is the main method for plasma heating in magnetic confinement fusion devices. In high energy injector (E>100 keV/amu), neutrals are obtained with reasonable efficiency by conversion of negative ions (H- or D-) via electron detachment reactions. In the case of ITER injectors, which shall operate at 1 MeV, a total ion current of ˜ 40 A is required to satisfy the heating power demand. Gridded electrodes are therefore used in the accelerator, so that 1280 negative ion beamlets are accelerated together. A carefully designed aiming system is required to control the beamlet trajectories, and to deliver their power on a focal point located several meters away from the beam source. In nowadays injectors, the aiming is typically obtained by aperture offset technique or by grid shaping. This paper discuss an alternative concept of beamlets aiming, based on an electrostatic "steerer" to be placed at the end of the accelerator. A feasibility study of this component is also presented, and its main advantages and drawbacks with respect to other methods are discussed.

  5. Electrostatic steering and beamlet aiming in large neutral beam injectors

    SciTech Connect

    Veltri, P. Chitarin, G.; Marcuzzi, D.; Sartori, E.; Serianni, G.; Sonato, P.; Cavenago, M.

    2015-04-08

    Neutral beam injection is the main method for plasma heating in magnetic confinement fusion devices. In high energy injector (E>100 keV/amu), neutrals are obtained with reasonable efficiency by conversion of negative ions (H- or D-) via electron detachment reactions. In the case of ITER injectors, which shall operate at 1 MeV, a total ion current of ∼ 40 A is required to satisfy the heating power demand. Gridded electrodes are therefore used in the accelerator, so that 1280 negative ion beamlets are accelerated together. A carefully designed aiming system is required to control the beamlet trajectories, and to deliver their power on a focal point located several meters away from the beam source. In nowadays injectors, the aiming is typically obtained by aperture offset technique or by grid shaping. This paper discuss an alternative concept of beamlets aiming, based on an electrostatic ”steerer” to be placed at the end of the accelerator. A feasibility study of this component is also presented, and its main advantages and drawbacks with respect to other methods are discussed.

  6. Beam steering by computer generated hologram for optical switches

    NASA Astrophysics Data System (ADS)

    Yamaguchi, Keita; Suzuki, Kenya; Yamaguchi, Joji

    2016-02-01

    We describe a computer generated hologram (CGH) method for application to a multiple input and multiple output (MxN) optical switch based on a liquid crystal on silicon (LCOS). The conventional MxN optical switch needs multiple spatial light modulations. However, the CGH method realizes an MxN optical switch simply with a one-time spatial light modulation, resulting in fewer optical elements and better cost efficiency. Moreover, the intrinsic loss of the proposed MxN switch resulting from beam splitting can be reduced by routing multiple signals with a single knob control, which is called a multi-pole multi-throw switch. In this paper, we demonstrate a 5x5 wavelength selective switch (WSS) and a 2-degree ROADM that we realized using the above CGH method. The experimental results indicate that these switches work well with a crosstalk of < -14.9 dB.

  7. Combining the switched-beam and beam-steering capabilities in a 2-D phased array antenna system

    NASA Astrophysics Data System (ADS)

    Tsai, Yi-Che; Chen, Yin-Bing; Hwang, Ruey-Bing

    2016-01-01

    This paper presents the development, fabrication, and measurement of a novel beam-forming system consisting of 16 subarray antennas, each containing four aperture-coupled patch antennas, and the application of this system in smart wireless communication systems. The beam patterns of each of the subarray antennas can be switched toward one of nine zones over a half space by adjusting the specific phase delay angles among the four antenna elements. Furthermore, when all subarrays are pointed at the same zone, slightly continuous beam steering in around 1° increments can be achieved by dynamically altering the progressive phase delay angle among the subarrays. Phase angle calibration was implemented by coupling each transmitter output and down converter into the in-phase/quadrature baseband to calculate the correction factor to the weight. In addition, to validate the proposed concepts and the fabricated 2-D phased array antenna system, this study measured the far-field radiation patterns of the aperture-coupled patch array integrated with feeding networks and a phase-calibration system to carefully verify its spatially switched-beam and beam-steering characteristics at a center frequency of 2.4 GHz which can cover the industrial, scientific, and medical band and some long-term evolution applications. In addition, measured results were compared with calculated results, and agreement between them was observed.

  8. MAcro-Electro-Mechanical Systems (MÆMS) based concept for microwave beam steering in reflectarray antennas

    NASA Astrophysics Data System (ADS)

    Momeni Hasan Abadi, Seyed Mohamad Amin; Booske, John H.; Behdad, Nader

    2016-08-01

    We present a new approach to perform beam steering in reflecting type apertures such as reflectarray antennas. The proposed technique exploits macro-scale mechanical movements of parts of the structure to achieve two-dimensional microwave beam steering without using any solid-state devices or phase shifters integrated within the aperture of the antenna. The principles of operation of this microwave beam steering technique are demonstrated in an aperture occupied by ground-plane-backed, sub-wavelength capacitive patches with identical dimensions. We demonstrate that by tilting the ground plane underneath the entire patch array layer, a phase shift gradient can be created over the aperture of the reflectarray that determines the direction of the radiated beam. Changing the direction and slope of this phase shift gradient on the aperture allows for performing beam steering in two dimensions using only one control parameter (i.e., tilt vector of the ground plane). A proof-of-concept prototype of the structure operating at X-band is designed, fabricated, and experimentally characterized. Experiments demonstrate that small mechanical movements of the ground plane (in the order of 0.05λ0) can be used to steer the beam direction in the ±10° in two dimensions. It is also demonstrated that this beam scanning range can be greatly enhanced to ±30° by applying this concept to the same structure when its ground plane is segmented.

  9. Modeling and simulations of new electrostatically driven, bimorph actuator for high beam steering micromirror deflection angles

    NASA Astrophysics Data System (ADS)

    Walton, John P.; Coutu, Ronald A.; Starman, LaVern

    2015-02-01

    There are numerous applications for micromirror arrays seen in our everyday lives. From flat screen televisions and computer monitors, found in nearly every home and office, to advanced military weapon systems and space vehicles, each application bringing with it a unique set of requirements. The microelectromechanical systems (MEMS) industry has researched many ways micromirror actuation can be accomplished and the different constraints on performance each design brings with it. This paper investigates a new "zipper" approach to electrostatically driven micromirrors with the intent of improving duel plane beam steering by coupling large deflection angles, over 30°, and a fast switching speed. To accomplish this, an extreme initial deflection is needed which can be reached using high stress bimorph beams. Currently this requires long beams and high voltage for the electrostatic pull in or slower electrothermal switching. The idea for this "zipper" approach is to stack multiple beams of a much shorter length and allow for the deflection of each beam to be added together in order to reach the required initial deflection height. This design requires much less pull-in voltage because the pull-in of one short beam will in turn reduce the height of the all subsequent beams, making it much easier to actuate. Using modeling and simulation software to characterize operations characteristics, different bimorph cantilever beam configurations are explored in order to optimize the design. These simulations show that this new "zipper" approach increases initial deflection as additional beams are added to the assembly without increasing the actuation voltage.

  10. On-ground calibration of AGILE-GRID with a photon beam: results and lessons for the future

    NASA Astrophysics Data System (ADS)

    Cattaneo, P. W.; Rappoldi, A.; Argan, A.; Buonomo, B.; Bulgarelli, A.; Chen, A. W.; D'Ammando, F.; Foggetta, L.; Fuschino, F.; Galli, M.; Gianotti, F.; Giuliani, A.; Longo, F.; Marisaldi, M.; Mazzitelli, G.; Pellizzoni, A.; Prest, M.; Pucella, G.; Quintieri, L.; Tavani, M.; Trifoglio, M.; Trois, A.; Valente, P.; Vallazza, E.; Vercellone, S.; Barbiellini, G.; Caraveo, P.; Costa, E.; De Paris, G.; Del Monte, E.; Di Cocco, G.; Donnarumma, I.; Evangelista, Y.; Ferrari, A.; Feroci, M.; Fiorini, M.; Giusti, M.; Labanti, C.; Lapshov, I.; Lazzarotto, F.; Lipari, P.; Lucarelli, F.; Mereghetti, S.; Morelli, E.; Moretti, E.; Morselli, A.; Pacciani, L.; Perotti, F.; Piano, G.; Picozza, P.; Pilia, M.; Rapisarda, M.; Rubini, A.; Sabatini, S.; Soffitta, P.; Striani, E.; Vittorini, V.; Zanello, D.; Colafrancesco, S.; Giommi, P.; Pittori, C.; Santolamazza, P.; Verrecchia, F.; Salotti, L.

    2012-09-01

    At the core of the AGILE scientific instrument, designed to operate on a satellite, there is the Gamma Ray Imaging Detector (GRID) consisting of a Silicon Tracker (ST), a Cesium Iodide Mini-Calorimeter and an Anti-Coincidence system of plastic scintillator bars. The ST needs an on-ground calibration with a γ-ray beam to validate the simulation used to calculate the energy response function and the effective area versus the energy and the direction of the γ rays. A tagged γ-ray beam line was designed at the Beam Test Facility (BTF) of the INFN Laboratori Nazionali of Frascati (LNF), based on an electron beam generating γ rays through bremsstrahlung in a position-sensitive target. The γ-ray energy is deduced by the difference with the post-bremsstrahlung electron energy1-.2 The electron energy is measured by a spectrometer consisting of a dipole magnet and an array of position sensitive silicon strip detectors, the Photon Tagging System (PTS). The use of the combined BTF-PTS system as tagged photon beam requires understanding the efficiency of γ-ray tagging, the probability of fake tagging, the energy resolution and the relation of the PTS hit position versus the γ-ray energy. This paper describes this study comparing data taken during the AGILE calibration occurred in 2005 with simulation.

  11. Two-axis Beam Steering Mirror Control system for Precision Pointing and Tracking Applications

    SciTech Connect

    Ulander, Klaus

    2006-01-01

    Precision pointing and tracking of laser beams is critical in numerous military and industrial applications. This is particularly true for systems requiring atmospheric beam propagation. Such systems are plagued by environmental influences which cause the optical signal to break up and wander. Example applications include laser communications, precision targeting, active imaging, chemical remote sensing, and laser vibrometry. The goal of this project is to build a beam steering system using a two-axis mirror to maintain precise pointing control. Ultimately, position control to 0.08% accuracy (40 {micro}rad) with a bandwidth of 200 Hz is desired. The work described encompasses evaluation of the instrumentation system and the subsequent design and implementation of an analog electronic controller for a two-axis mirror used to steer the beam. The controller operates over a wide temperature range, through multiple mirror resonances, and is independent of specific mirrors. The design was built and successfully fielded in a Lawrence Livermore National Laboratory free-space optics experiment. All measurements and performance parameters are derived from measurements made on actual hardware that was built and field tested. In some cases, specific design details have been omitted that involve proprietary information pertaining to Lawrence Livermore National Laboratory patent positions and claims. These omissions in no way impact the general validity of the work or concepts presented in this thesis.

  12. Report for simultaneous, multiple independently steered beam study for Airborne Electronically Steerable Phased Array (AESPA) program

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Design concepts of an array for the formation of multiple, simultaneous, independently pointed beams for satellite communication links were investigated through tradeoffs of various approaches which were conceived as possible solutions to the problem. After the preferred approach was selected, a more detailed design was configured and is presented as a candidate system that should be given further consideration for development leading to a preliminary design. This array uses an attenuator and a phase shifter with every element. The aperture excitation necessary to form the four beams is calculated and then placed across the array using these devices. Pattern analysis was performed for two beam and four beam cases with numerous patterns being presented. Parameter evaluation shown includes pointing accuracy and beam shape, sidelobe characteristics, gain control, and beam normalization. It was demonstrated that a 4 bit phase shifter and a 6 bit, 30 dB attenuator were sufficient to achieve adequate pattern performances. The phase amplitude steered multibeam array offers the flexibility of 1 to 4 beams with an increase in gain of 6 dB if only one beam is selected.

  13. The influence of wavelength in extinction measurements and beam steering in laser-induced incandescence measurements in sooting flames

    NASA Astrophysics Data System (ADS)

    Zerbs, J.; Geigle, K. P.; Lammel, O.; Hader, J.; Stirn, R.; Hadef, R.; Meier, W.

    2009-09-01

    The accuracy of laser-induced incandescence (LII) measurements is significantly influenced by the calibration process and the laser profile degradation due to beam steering. Additionally, the wavelength used for extinction measurements, needed for LII calibration, is critical and should be kept as high as possible in order to avoid light absorption by molecular species in the flame. The influence of beam steering on the LII measurement was studied in turbulent sooting C2H4/air flames at different pressures. While inhomogeneities in the laser profile become smoothed out in time-averaged measurements, especially at higher pressure, the corresponding single-shot beam profiles reveal an increasing effect of beam steering. In the current configuration it was observed that the resulting local laser fluence remains within certain limits (30% to 200%) of the original value. A sufficiently high incident laser fluence can thus prevent the local fluence from dropping below the LII threshold value of approximately 0.3 J/cm2 at the cost of increased soot surface vaporization. A spatial resolution in the dimension of the sheet thickness of below 1 mm cannot be guaranteed at increased pressure of 9 bars due to beam steering. A feasibility study in a combustor at technical conditions demonstrates the influence of both effects beam steering and choice of calibration wavelength and led to the conclusion that, however, a shot-to-shot calibration of LII with simultaneously measured extinction can be realized.

  14. Beam steering in superconducting quarter-wave resonators: An analytical approach

    NASA Astrophysics Data System (ADS)

    Facco, Alberto; Zvyagintsev, Vladimir

    2011-07-01

    Beam steering in superconducting quarter-wave resonators (QWRs), which is mainly caused by magnetic fields, has been pointed out in 2001 in an early work [A. Facco and V. Zviagintsev, in Proceedings of the Particle Accelerator Conference, Chicago, IL, 2001 (IEEE, New York, 2001), p. 1095], where an analytical formula describing it was proposed and the influence of cavity geometry was discussed. Since then, the importance of this effect was recognized and effective correction techniques have been found [P. N. Ostroumov and K. W. Shepard, Phys. Rev. ST Accel. Beams 4, 110101 (2001)PRABFM1098-440210.1103/PhysRevSTAB.4.110101]. This phenomenon was further studied in the following years, mainly with numerical methods. In this paper we intend to go back to the original approach and, using well established approximations, derive a simple analytical expression for QWR steering which includes correction methods and reproduces the data starting from a few calculable geometrical constants which characterize every cavity. This expression, of the type of the Panofski equation, can be a useful tool in the design of superconducting quarter-wave resonators and in the definition of their limits of application with different beams.

  15. Fast beam steering with full polarization control using a galvanometric optical scanner and polarization controller.

    PubMed

    Jofre, M; Anzolin, G; Steinlechner, F; Oliverio, N; Torres, J P; Pruneri, V; Mitchell, M W

    2012-05-21

    Optical beam steering is a key element in many industrial and scientific applications like in material processing, information technologies, medical imaging and laser display. Even though galvanometer-based scanners offer flexibility, speed and accuracy at a relatively low cost, they still lack the necessary control over the polarization required for certain applications. We report on the development of a polarization steerable system assembled with a fiber polarization controller and a galvanometric scanner, both controlled by a digital signal processor board. The system implements control of the polarization decoupled from the pointing direction through a feed-forward control scheme. This enables to direct optical beams to a desired direction without affecting its initial polarization state. When considering the full working field of view, we are able to compensate polarization angle errors larger than 0.2 rad, in a temporal window of less than ∼ 20 ms. Given the unification of components to fully control any polarization state while steering an optical beam, the proposed system is potentially integrable and robust.

  16. Fast beam steering with full polarization control using a galvanometric optical scanner and polarization controller.

    PubMed

    Jofre, M; Anzolin, G; Steinlechner, F; Oliverio, N; Torres, J P; Pruneri, V; Mitchell, M W

    2012-05-21

    Optical beam steering is a key element in many industrial and scientific applications like in material processing, information technologies, medical imaging and laser display. Even though galvanometer-based scanners offer flexibility, speed and accuracy at a relatively low cost, they still lack the necessary control over the polarization required for certain applications. We report on the development of a polarization steerable system assembled with a fiber polarization controller and a galvanometric scanner, both controlled by a digital signal processor board. The system implements control of the polarization decoupled from the pointing direction through a feed-forward control scheme. This enables to direct optical beams to a desired direction without affecting its initial polarization state. When considering the full working field of view, we are able to compensate polarization angle errors larger than 0.2 rad, in a temporal window of less than ∼ 20 ms. Given the unification of components to fully control any polarization state while steering an optical beam, the proposed system is potentially integrable and robust. PMID:22714214

  17. Planar laser-induced incandescence of turbulent sooting flames: the influence of beam steering and signal trapping

    NASA Astrophysics Data System (ADS)

    Sun, Z. W.; Alwahabi, Z. T.; Gu, D. H.; Mahmoud, S. M.; Nathan, G. J.; Dally, B. B.

    2015-03-01

    The influence of beam steering and signal trapping on the accuracy of soot volume fractions measured using planar laser-induced incandescence (LII) has been investigated in turbulent non-premixed sooting flames at atmospheric pressure. In turbulent non-premixed C2H4/air flames, the influence of local de-focusing/focusing of the laser sheet from beam steering can result in the underestimate of the averaged LII signal by 30 %, even when operating within the so-called plateau regime of laser fluence. Beam steering was also found to be significant in both the upstream region of C2H4/air flames and non-reacting C2H4 flows, because the fuel has a relatively high refractive index compared with ambient air. The extent of beam steering at different heights of reacting and isothermal flows as well as its dependence on exit Reynolds number (Re) has been measured. The measurements reveal that even at low turbulence levels (2000 < Re < 3000), beam steering effects can be significant. Also found is that the LII signal at a 450 nm wavelength can be attenuated by a few per cent at high soot loading regions in turbulent flames due to signal trapping. Finally, the feasibility of directly evaluating the signal attenuation via planar LII results was assessed by comparing the virtual soot attenuation calculated based on the planar LII result with that measured using light-of-sight extinction.

  18. Polymeric waveguide electro-optic beam-steering device with DNA biopolymer conductive cladding layers

    NASA Astrophysics Data System (ADS)

    Aga, Roberto S.; Ouchen, Fahima; Lesko, Alyssa; Telek, Brian A.; Fehrman Cory, Emily M.; Bartsch, Carrie M.; Lombardi, Jack; Grote, James; Heckman, Emily M.

    2012-11-01

    A polymer electro-optic (EO) waveguide beam-steering device with deoxyribonucleic acid (DNA) biopolymer conductive cladding layers and a core layer of the commercially available EO polymer SEO100 is demonstrated with 100% relative poling efficiency. This demonstration device exhibits a deflection efficiency of 99 mrad/kV with a corresponding in-device EO coefficient r33 of 124 pm/V at 1550 nm. When the DNA biopolymer bottom cladding layer is replaced by the commonly used cladding polymer UV15, the deflection efficiency and in-device r33 drop to 34 mrad/kV and 43 pm/V, respectively.

  19. Electronically controlled optical beam-steering by an active phased array of metallic nanoantennas.

    PubMed

    DeRose, C T; Kekatpure, R D; Trotter, D C; Starbuck, A; Wendt, J R; Yaacobi, A; Watts, M R; Chettiar, U; Engheta, N; Davids, P S

    2013-02-25

    An optical phased array of nanoantenna fabricated in a CMOS compatible silicon photonics process is presented. The optical phased array is fed by low loss silicon waveguides with integrated ohmic thermo-optic phase shifters capable of 2π phase shift with ∼ 15 mW of applied electrical power. By controlling the electrical power to the individual integrated phase shifters fixed wavelength steering of the beam emitted normal to the surface of the wafer of 8° is demonstrated for 1 × 8 phased arrays with periods of both 6 and 9 μm. PMID:23482053

  20. Evaluation of an optical beam-position-monitor system with closed-loop steering capabilities

    NASA Astrophysics Data System (ADS)

    Bissen, Mark; Rogers, Greg; Wood, William; Eisert, Dave; Kleman, K. J.; Winter, William; Höchst, Hartmut

    1994-08-01

    Imaging the synchrotron source profile onto the entrance slit of a monochromator provides a stable and reproducible energy calibration which is independent of the absolute position and drift of the electron beam. Potential electron-beam motions occurring during a fill result in a loss of flux through the beamline. We have implemented two independent beam position monitors which can be used as sensors to steer the vertical entrance mirror in order to maintain a maximum flux through a spherical grating varied line-spacing monochromator beamline. The system consists of a slotted plate photodiode which intercepts 2 mrad of synchrotron radiation next to the entrance mirror and a detector utilizing the photocurrents generated at the jaws of the entrance-slit assembly. Both monitors have a wide linear response range with a vertical position resolution of < 5 μm. The combination of two independent beam position monitors allows an easy check on the mechanical and thermal stability of the entrance optical system as well as on the reproducibility and long-term fluctuations of the electron-beam source during user shifts. We will discuss the performance of the optical beam-position-monitor system and its implementation as a sensor in a closed-loop feedback system to maintain maximum flux through the beamline.

  1. Digital Beam Steering Device Based on Decoupled Birefringent Prism Deflector and Polarization Rotator

    NASA Technical Reports Server (NTRS)

    Pishnyak, Oleg; Kreminska, Lyubov; Laventovich, Oleg D.; Pouch, John J.; Miranda, Felix A.; Winker, Bruce K.

    2004-01-01

    We describe digital beam deflectors (DBDs) based on liquid crystals. Each stage of the device comprises a polarization rotator and a birefringent prism deflector. The birefringent prism deflects the beam by an angle that depends on polarization of the incident beam. The prism can be made of the uniaxial smectic A (SmA) liquid crystal (LC) or a solid crystal such as yttrium orthovanadate (YVO4). SmA prisms have high birefringence and can be constructed in a variety of shapes, including single prisms and prismatic blazed gratings of different angles and profiles. We address the challenges of uniform alignment of SmA, such as elimination of focal conic domains. Rotation of linear polarization is achieved by an electrically switched twisted nematic (TN) cell. A DBD composed of N rotator-deflector pairs steers the beam into 2(sup N) directions. As an example, we describe a four-stage DBD deflecting normally incident laser beam within the range of +/- 56 mrad with 8 mrad steps. Redirection of the beam is achieved by switching the TN cells.

  2. Compact, flexible, frequency agile parametric wavelength converter

    DOEpatents

    Velsko, Stephan P.; Yang, Steven T.

    2002-01-01

    This improved Frequency Agile Optical Parametric Oscillator provides near on-axis pumping of a single QPMC with a tilted periodically poled grating to overcome the necessity to find a particular crystal that will permit collinear birefringence in order to obtain a desired tuning range. A tilted grating design and the elongation of the transverse profile of the pump beam in the angle tuning plane of the FA-OPO reduces the rate of change of the overlap between the pumped volume in the crystal and the resonated and non-resonated wave mode volumes as the pump beam angle is changed. A folded mirror set relays the pivot point for beam steering from a beam deflector to the center of the FA-OPO crystal. This reduces the footprint of the device by as much as a factor of two over that obtained when using the refractive telescope design.

  3. High-performance beam steering using electrowetting-driven liquid prism fabricated by a simple dip-coating method

    NASA Astrophysics Data System (ADS)

    Enrico Clement, Carlos; Park, Sung-Yong

    2016-05-01

    A high degree of beam steering is demonstrated using an electrowetting-driven liquid prism. While prism devices have typically relied on complex and expensive laboratory setups, such as high-vacuum facilities for fabrication of dielectric layers, this work utilizes a simple dip-coating method to provide an ion gel layer as a dielectric, offering 2 or 3 orders higher specific capacitance (c ≈ 10 μF/cm2) than that of conventional dielectrics. Analytical studies present the effects of liquid selection and arrangement on overall prism performance. For experimental demonstrations of high-performance beam steering, we not only selected two immiscible liquids of water and 1-bromonaphthalene (1-BN) oil which provide the large refractive index difference (nwater = 1.33 and n1-BN = 1.65 at λ = 532 nm) between them, but also utilized a double-stacked prism configuration which increases the number of interfaces for incoming light to be steered. At a prism apex angle of φ = 27°, we were able to achieve significantly large beam steering of up to β = 19.06°, which is the highest beam steering performance ever demonstrated using electrowetting technology.

  4. High power microwave beam steering based on gyromagnetic nonlinear transmission lines

    SciTech Connect

    Romanchenko, I. V. Rostov, V. V.; Gunin, A. V.; Konev, V. Yu.

    2015-06-07

    We demonstrate electronically controlled beam steering by high power RF pulses produced by two gyromagnetic nonlinear transmission lines (NLTLs) connected to a one high voltage driver. Each NLTL is capable of producing several ns RF pulses with peak power from 50 to 700 MW (6% standard deviation) at frequencies from 0.5 to 1.7 GHz (1% standard deviation) with 100 Hz repetition rate. Using a helix antenna allows irradiating of RF pulses with almost circular polarization and 350 MW maximum peak power, which corresponds to 350 kV effective potential of radiation. At the installation of two identical channels, we demonstrate the possibility of beam steering within ±15° in the horizontal plane by coherent RF pulses with circular polarization at 1.0 GHz center frequency. Fourfold increase in the power flux density for in-phase irradiation of RF pulses is confirmed by comparison with one-channel operation.

  5. Low Cost Beam-Steering Approach for a Series-Fed Array

    NASA Technical Reports Server (NTRS)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda, Felix A.

    2013-01-01

    Phased array antennas showcase many advantages over mechanically steered systems. However, they are also more complex and costly. This paper presents a concept which overcomes these detrimental attributes by eliminating all of the phased array backend (including phase shifters). Instead, a propagation constant reconfigurable transmission line in a series fed array arrangement is used to allow phase shifting with one small (less than or equal to 100mil) linear mechanical motion. A novel slotted coplanar stripline design improves on previous transmission lines by demonstrating a greater control of propagation constant, thus allowing practical prototypes to be built. Also, beam steering pattern control is explored. We show that with correct choice of line impedance, pattern control is possible for all scan angles. A 20 element array scanning from -25 deg less than or equal to theta less than or equal to 21 deg. with mostly uniform gain at 13GHz is presented. Measured patterns show a reduced scan range of 12 deg. less than or equal to theta less than or equal to 25 deg. due to a correctable manufacturing error as verified by simulation. Beam squint is measured to be plus or minus 2.5 deg for a 600MHz bandwidth and cross-pol is measured to be at least -15dB.

  6. New design of a beam-steering thermooptic multimode polymer waveguide switch

    NASA Astrophysics Data System (ADS)

    Ma, C.; van Keuren, E.

    2006-12-01

    We present simulations of a Y-branch directional coupler activated using the thermooptic effect in a multimode polymer waveguide. Microheaters embedded beneath both sides of the waveguide at the Y-branch are used to generate an inhomogeneous temperature profile. Through the thermooptic effect, this temperature profile creates a refractive index profile in the channel waveguide material, which steers the beam to one of the two output branches. We determined the expected thermal profiles using finite element modeling (FEM). The transmission of a basic mode through the waveguide was then simulated using the beam propagation method (BPM). The results show that a high contrast ratio (>90%) can be achieved in response times on the order of 1 ms.

  7. Focusing, wavelength tuning, beam steering and beam shaping of circular grating surface emitting distributed Bragg reflector lasers

    NASA Astrophysics Data System (ADS)

    Penner, Robert Scott

    Over the past decade, circular grating surface emitting DBR lasers (CGSELs) have progressed from theory to reality. These devices possess several properties that make them attractive options for such applications as optical interconnects and laser arrays. These advantages include low divergence angles, circular beam profiles, and high power output. In this dissertation, the addition of new functionality to these lasers including wavelength tunability, focusing, beam steering and beam shaping is investigated. The theory governing device operation is presented. Pertinent discussions include the coupled mode equations, grating coupling, focusing and changes to the effective index of refraction resulting from current injection through a transparent electrode on the grating. The development and refinement of the device fabrication process is detailed. Key milestones in the grating writing process included achieving first order gratings (Λ = 0.15 μm), creating chirped period gratings for focusing and optimizing the linewidth and uniformity of the grating for high power devices. Of equal importance in obtaining high efficiency devices was the reactive ion etch process. Two different etch recipes were developed: one for mesa-definition and a shallower grating-defining etch. Significant evaluation of the electrical and optical properties of the transparent electrode, Indium Tin Oxide, was performed. Incorporating ITO into the fabrication process required optimization of deposition, patterning, etching and annealing. Device performance, efficiency and functionality improved with each generation. Consequentially, over 225 mW of output power for a injection current of 600 mA, or a slope efficiency of 0.43 mW/mA, was produced by the final generation of high power CGSELs. Focusing was demonstrated by the creation of individual devices with different focal lengths. Coarse mode selection was obtained by removing radial segments of the circular grating thereby eliminating both

  8. A Novel Approach to Beam Steering Using Arrays Composed of Multiple Unique Radiating Modes

    NASA Astrophysics Data System (ADS)

    Labadie, Nathan Richard

    Phased array antennas have found wide application in both radar and wireless communications systems particularly as implementation costs continue to decrease. The primary advantages of electronically scanned arrays are speed of beam scan and versatility of beamforming compared to mechanically scanned fixed beam antennas. These benefits come at the cost of a few well known design issues including element pattern rolloff and mutual coupling between elements. Our primary contribution to the field of research is the demonstration of significant improvement in phased array scan performance using multiple unique radiating modes. In short, orthogonal radiating modes have minimal coupling by definition and can also be generated with reduced rolloff at wide scan angles. In this dissertation, we present a combination of analysis, full-wave electromagnetic simulation and measured data to support our claims. The novel folded ring resonator (FRR) antenna is introduced as a wideband and multi-band element embedded in a grounded dielectric substrate. Multiple radiating modes of a small ground plane excited by a four element FRR array were also investigated. A novel hemispherical null steering antenna composed of two collocated radiating elements, each supporting a unique radiating mode, is presented in the context of an anti-jam GPS receiver application. Both the antenna aperture and active feed network were fabricated and measured showing excellent agreement with analytical and simulated data. The concept of using an antenna supporting multiple radiating modes for beam steering is also explored. A 16 element hybrid linear phased array was fabricated and measured demonstrating significantly improved scan range and scanned gain compared to a conventional phased array. This idea is expanded to 2 dimensional scanning arrays by analysis and simulation of a hybrid phased array composed of novel multiple mode monopole on patch antenna sub-arrays. Finally, we fabricated and

  9. Beam steering for virtual/augmented reality displays with a cycloidal diffractive waveplate.

    PubMed

    Chen, Haiwei; Weng, Yishi; Xu, Daming; Tabiryan, Nelson V; Wu, Shin-Tson

    2016-04-01

    We proposed a switchable beam steering device with cycloidal diffractive waveplate (CDW) for eye tracking in a virtual reality (VR) or augmented reality (AR) display system. Such a CDW diffracts the incident circularly polarized light to the first order with over 95% efficiency. To convert the input linearly polarized light to right-handed or left-handed circular polarization, we developed a broadband polarization switch consisting of a twisted nematic liquid crystal cell and an achromatic quarter-wave retardation film. By cascading 2-3 CDWs together, multiple diffraction angles can be achieved. To suppress the color dispersion, we proposed two approaches to obtain the same diffraction angle for red, green, and blue LEDs-based full color displays. Our device exhibits several advantages, such as high diffraction efficiency, fast response time, low power consumption, and low cost. It holds promise for the emerging VR/AR displays. PMID:27137019

  10. Acoustic prism for continuous beam steering based on piezo-electric metamaterial

    NASA Astrophysics Data System (ADS)

    Xu, J.; Tang, J.

    2016-04-01

    This paper investigates an acoustic prism for continuous acoustic beam steering by a simple frequency sweep. This idea takes advantages of acoustic wave velocity shifting in metamaterials in the vicinity of local resonance. We apply this concept into the piezoelectric metamaterial consisting of host medium and piezoelectric LC shunt. Theoretical modeling and FEM simulations are carried out. It is shown that the phase velocity of acoustic wave changes dramatically in the vicinity of local resonance. The directions of acoustic wave can be adjusted continuously between 2 to 16 degrees by a simple sweep of the excitation frequency. Such an electro-mechanical coupling system has a feature of adjusting local resonance without altering the mechanical part of the system.

  11. Highly bent (110) Ge crystals for efficient steering of ultrarelativistic beams

    SciTech Connect

    De Salvador, D.; Maggioni, G.; Carturan, S.; Bazzan, M.; Argiolas, N.; Carnera, A.; Dalla Palma, M.; Della Mea, G.; Bagli, E.; Mazzolari, A.; Bandiera, L.; Guidi, V.; Lietti, D.; Berra, A.; Guffanti, G.; Prest, M.; Vallazza, E.

    2013-10-21

    Thanks to the effective electrostatic potential generated by the ordered atomic structure, bent crystals can efficiently deflect ultra relativistic charged beams by means of planar and axial channeling phenomena as well as of the recently discovered volume reflection effect. Most of the experimental knowledge about these phenomena has been gathered with Si crystals, but it has been recently demonstrated that the steering performance can be improved by using high quality Ge materials which have a larger atomic number. In this paper, we investigate channeling and volume reflection of 400 GeV protons from (110) lattice planes in highly bent Ge strips crystals. Both production and characterization of the strips are presented. Herein, the experimental results on deflection are compared with theoretical predictions, with previous published data and with the expected performances of Si crystals in similar experimental conditions.

  12. Reflectarray for 120-GHz beam steering application: design, simulations, and measurements

    NASA Astrophysics Data System (ADS)

    Tamminen, Aleksi; Ala-Laurinaho, Juha; Gomes-Martins, David; Häkli, Janne; Koivisto, Päivi; Kärkkäinen, Mikko; Mäkelä, Sampo; Pursula, Pekka; Rantakari, Pekka; Sipilä, Markku; Säily, Jussi; Tuovinen, Reijo; Varonen, Mikko; Halonen, Kari A. I.; Luukanen, Arttu; Räisänen, Antti V.

    2012-06-01

    Development of a 120-GHz FMCW radar with a reflectarray as focusing element is described. The reflectarray is realized on a 150-mm silicon wafer and it has 3700 phase-modulating elements on it. The phase shifters have four discrete values to cover full phase modulation with 90° steps. The reflectarray element is realized with a conductor-backed coplanar waveguide patch antenna with a phase shifter coupled to it. The required phase modulation for each reflectarray element is determined with an in-house physical optics simulation combined with genetic-algorithm-based optimization. The reflectarrays are developed in two stages. First, preliminary reflectarrays with static phase shifters have been manufactured and tested at 120-GHz antenna measurement range. The static reflectarrays are found to perform as designed in their capability to steer the beam to a desired direction and to a distance of 3 m. The reflectarrays have -3-dB beam width from 1.1° to 1.3° depending on the beam tilt. After the preliminary verification with the static phase shifters, the reflectarrays will be assembled together with actively controlled MEMS-based phase shifters. The MEMS switches are controlled with dedicated high-voltage CMOS electronics, forming a system-in-a-package (SiP). First, the MEMS phase shifters are modeled, are being fabricated, and will be measured separately to verify their phase-shifting capability.

  13. Broadband polarization gratings for efficient liquid crystal display, beam steering, spectropolarimetry, and Fresnel zone plate

    NASA Astrophysics Data System (ADS)

    Oh, Chulwoo

    displays is the polymer-PG display, which allows an immediate brightness improvement (up to a factor of two) of conventional LC displays by replacing absorbing polarizers with achromatic PGs as thin, transmissive polymer films. We demonstrate the first proof-of-concept prototype projector based on the polymer-PG display and we also discuss optical design considerations and challenges toward a viable solution for our ultrabright pico-projector applications of the polymer-PG display. Second, two novel beam steering concepts based on the PG diffraction have been proposed. The polarization-sensitive diffraction of the PGs provides very attractive beam steering operations with ultra-high efficiency over wide steering angles by all-thin-plate electro-optical systems. We developed a non-mechanical, wide-angle beam steering system using stacked PGs and LC waveplates, and we also demonstrated a continuous beam steering using two rotating PGs, named the Risley grating as a thin-plate version of the Risley prism. The third PG application is in imaging and non-imaging spectropolarimetry. We have shown a snapshot, hyperspectral, full-Stokes polarimeter using inline PGs and quarter-waveplates. The use of PGs as a new polarimetric element for astronomical instruments in the mid-wave IR wavelengths also has been proposed to overcome current limitations of existing IR polarimeters. In the last part of this Dissertation, we introduce a polarization-type Fresnel zone plates (P-FZPs), comprising of spatially distributed linear birefringence or concentric PG (CPG) patterns. Effective fabrication methods of P-FZPs have been developed using polarization holography based on the Michelson interferometer and photoalignment of LC materials. We demonstrated high-quality P-FZPs, which exhibit ideal Fresnel-type lens effects, formed as both LC polymer films and electro-optical LC devices. We also discuss the polarization-selective lens properties of the P-FZPs as well as their electro-optical switching

  14. Positioning Agility

    NASA Astrophysics Data System (ADS)

    Oza, Nilay; Abrahamsson, Pekka; Conboy, Kieran

    Agile methods are increasingly adopted by European companies. Academics too are conducting numerous studies on different tenets of agile methods. Companies often feel proud in marketing themselves as ‘agile’. However, the true notion of ‘being agile’ seems to have been overlooked due to lack of positioning of oneself for agility. This raises a call for more research and interactions between academia and the industry. The proposed workshop refers to this call. It will be highly relevant to participants, interested in positioning their company’s agility from organizational, group or project perspectives. The positioning of agility will help companies to better align their agile practices with stakeholder values. Results of the workshop will be shared across participants and they will also have opportunity to continue their work on agile positioning in their companies. At broader level, the work done in this workshop will contribute towards developing Agile Positioning System.

  15. Diode laser lidar wind velocity sensor using a liquid-crystal retarder for non-mechanical beam-steering.

    PubMed

    Rodrigo, Peter John; Iversen, Theis F Q; Hu, Qi; Pedersen, Christian

    2014-11-01

    We extend the functionality of a low-cost CW diode laser coherent lidar from radial wind speed (scalar) sensing to wind velocity (vector) measurements. Both speed and horizontal direction of the wind at ~80 m remote distance are derived from two successive radial speed estimates by alternately steering the lidar probe beam in two different lines-of-sight (LOS) with a 60° angular separation. Dual-LOS beam-steering is implemented optically with no moving parts by means of a controllable liquid-crystal retarder (LCR). The LCR switches the polarization between two orthogonal linear states of the lidar beam so it either transmits through or reflects off a polarization splitter. The room-temperature switching time between the two LOS is measured to be in the order of 100 μs in one switch direction but 16 ms in the opposite transition. Radial wind speed measurement (at 33 Hz rate) while the lidar beam is repeatedly steered from one LOS to the other every half a second is experimentally demonstrated - resulting in 1 Hz rate estimates of wind velocity magnitude and direction at better than 0.1 m/s and 1° resolution, respectively.

  16. Diode laser lidar wind velocity sensor using a liquid-crystal retarder for non-mechanical beam-steering.

    PubMed

    Rodrigo, Peter John; Iversen, Theis F Q; Hu, Qi; Pedersen, Christian

    2014-11-01

    We extend the functionality of a low-cost CW diode laser coherent lidar from radial wind speed (scalar) sensing to wind velocity (vector) measurements. Both speed and horizontal direction of the wind at ~80 m remote distance are derived from two successive radial speed estimates by alternately steering the lidar probe beam in two different lines-of-sight (LOS) with a 60° angular separation. Dual-LOS beam-steering is implemented optically with no moving parts by means of a controllable liquid-crystal retarder (LCR). The LCR switches the polarization between two orthogonal linear states of the lidar beam so it either transmits through or reflects off a polarization splitter. The room-temperature switching time between the two LOS is measured to be in the order of 100 μs in one switch direction but 16 ms in the opposite transition. Radial wind speed measurement (at 33 Hz rate) while the lidar beam is repeatedly steered from one LOS to the other every half a second is experimentally demonstrated - resulting in 1 Hz rate estimates of wind velocity magnitude and direction at better than 0.1 m/s and 1° resolution, respectively. PMID:25401817

  17. Efficient multibeam large-angle nonmechanical laser beam steering from computer-generated holograms rendered on a liquid crystal spatial light modulator.

    PubMed

    Lindle, James R; Watnik, Abbie T; Cassella, Vincent A

    2016-06-01

    Multibeam large-angle beam steering is demonstrated in the visible spectral region by imprinting computer-generated holographic Fresnel zone plates on a liquid crystal spatial light modulator (SLM) configured as the first element of a telescope. The position and intensity of each beam are controlled independently. The laser beam is steered over a ±37° field of regard, with the power in the beam at 37° being greater than 50% of the on-axis power. The power delivered on axis for a single beam was 48% of the power incident on the SLM. The beam profile remained Gaussian over the full steering range, and the on-axis beam divergence is 2.1 mrad. PMID:27411184

  18. Integrated remotely tunable optical delay line for millimeter-wave beam steering fabricated in an InP generic foundry.

    PubMed

    Cao, Z; Tessema, N; Latkowski, S; Zhao, X; Chen, Z; Moskalenko, V; Williams, K A; van der Boom, H P A; Tangdiongga, E; Koonen, A M J

    2015-09-01

    A compact and fabrication-tolerant integrated remotely tunable optical delay line is proposed for millimeter-wave beam steering and is fabricated in an InP generic foundry. The proposed delay line is based on a spectrally cyclic-arrayed waveguide grating feedback loop. Its major features include the tolerant architecture with reduced chip size, and bi-directional operation with simplified remote tuning. Moreover, its cyclic feature guarantees further cascaded operations either for 2D radio beam steering or for high-resolution delay generation. The experimental results show less than 6.5-dB insertion loss of the integrated delay line. Five different delays from 0 to 71.6 ps are generated with less than 0.67-ps delay errors.

  19. Use of Rayleigh imaging and ray tracing to correct for beam-steering effects in turbulent flames.

    PubMed

    Kaiser, Sebastian A; Frank, Jonathan H; Long, Marshall B

    2005-11-01

    Laser Rayleigh imaging has been applied in a number of flow and flame studies to measure concentration or temperature distributions. Rayleigh cross sections are dependent on the index of refraction of the scattering medium. The same index of refraction changes that provide contrast in Rayleigh images can also deflect the illuminating laser sheet. By applying a ray-tracing algorithm to the detected image, it is possible to correct for some of these beam-steering effects and thereby improve the accuracy of the measured field. Additionally, the quantification of the degree of beam steering through the flow provides information on the degradation of spatial resolution in the measurement. Application of the technique in a well-studied laboratory flame is presented, along with analysis of the effects of image noise and spatial resolution on the effectiveness of the algorithm. PMID:16270544

  20. MIMO based optical phased array technology with electronic beam steering for laser radar applications

    NASA Astrophysics Data System (ADS)

    Sharma, Neha; Zmuda, Henry

    2010-04-01

    This paper will address the analysis and design of an electronically scanned phased array laser radar (ladar) system utilizing the techniques of multi-input multi-output (MIMO) array design. MIMO radar is has attracted much attention recently from both researchers and practitioners alike due to its significant potential for advancing the state-of-the-art RF radar technology. The laser radar architecture presented stands to gain significant inroads on the ability to apply RF array processing methods to laser radar systems in several ways. Specifically, using MIMO array design concepts, it is shown that the resolution of the ladar array can substantially exceed the diffraction limited resolution of a conventional array. Additionally, the use of array methods provides the capability to electronically steer the aperture, thus avoiding the mechanical beam scanning methods generally encountered in laser radar systems. Finally, by using an array of radiators, an increase in total radiated power is achieved, relieving the power burden on a single laser. The problems traditionally encountered in applying conventional array techniques to laser/detector arrays, for example, the inability to achieve half-wavelength spacing or the surfacing of source coherence issues, actually work to one's advantage when viewed in the MIMO paradigm. It is anticipated that the successful implementation of this system will significantly advance the state-of-the-art of laser radar capabilities for high speed imaging, target detection, tracking, and signature analysis.

  1. Metamaterial loading of electrically small patch antennas to enable beam steering up to the horizon

    NASA Astrophysics Data System (ADS)

    Pai Raikar, Vandita Rajiv

    This thesis research has been conducted with an aim of investigating the effects of metamaterials on microstrip patch antennas. Metamaterials exhibit interesting properties such as single negative or simultaneous double negative values of relative permittivity and permeability, due to which they have gained immense popularity. The influence of metamaterials on traditional patch antennas has been a topic of focus throughout this research. Different metamaterial unit cells have been designed to possess satisfactory behavior in terms of permittivity and permeability. The use of metamaterials as a substrate for patch antennas has been explored, highlighting the possibility of designing electrically small patch antennas. Several metamaterial unit cells and modified patch antennas have been designed and modeled in Ansys HFSS, a highly competent full wave electromagnetic solver. On achieving a satisfactory results from a single patch antenna, the same concept has been applied to design a planar phased array patch antenna having 8x8 elements. The planar phased array antenna will be designed to enable beam steering from broadside toward the horizon.

  2. Ultra-thin two-dimensional transmissive anisotropic metasurfaces for polarization filter and beam steering application

    NASA Astrophysics Data System (ADS)

    Guo, Wen-Long; Wang, Guang-Ming; Li, Hai-Peng; Zhang, Kun; Cai, Tong

    2016-10-01

    We propose an anisotropic planar transmitting metasurface, which has the ability to manipulate orthogonally-polarized electromagnetic waves in the reflection and refraction modes respectively. The metasurface is composed of four layered rectangular patches spaced by three layered dielectric isolators each with a thickness of 0.15λ 0 at 15 GHz. By tailoring the sizes of the patches, the metasurface functions as a band-stop filter for the y-polarzied wave and a band-pass filter for the x-polarized wave operating from 14 GHz to 16 GHz. Moreover the phases of the transmitting x-polarized wave can be modulated at about 15 GHz, which contributes to beam steering according to the general refraction law. Experimental results are in good accordance with the simulated ones, in which the reflection efficiency is almost 100% while the transmission efficiency of the x-polarized wave reaches 80% at 15 GHz. Besides, the transmitted x-polarized wave is effectively manipulated from 14 GHz to 16 GHz. Project supported by the National Natural Science Foundation of China (Grant No. 61372034).

  3. Automated test device for FASR (Fixed Array Surveillance Radar) beam steering componentry

    NASA Astrophysics Data System (ADS)

    Scott, Russell A.

    1988-02-01

    The Fixed Array Surveillance Radar System uses an automated test device known as the Axis Box Tester. An axis box serves as a distribution point connecting the horizontal and vertical busses of the array and monitors the rf of phase shifters and aids with beam steering. The tester diagnoses axis boxes and verifies proper operation. All digital circuitry is tested, including all data flow paths to and from the phase shifters, all control line information, and all circuitry to select rows and columns. The tester attempts to provide information that will aid, if not solve problems. The software is parsed into modules that perform various tests upon the axis box. The hardware, which uses a single-board computer with an Intel 8086 microprocessor, provides the interface between the microprocessor and the axis box. The tester provides very accurate diagnostics and can reduce debugging time by a factor of 100. Some problems prevent the tester from doing more than guessing at possible causes of a problem.

  4. Ultra-Wideband, Dual-Polarized, Beam-Steering P-Band Array Antenna

    NASA Technical Reports Server (NTRS)

    duToit, Cornelis

    2014-01-01

    A dual-polarized, wide-bandwidth (200 MHz for one polarization, 100 MHz for the orthogonal polarization) antenna array at P-band was designed to be driven by NASA's EcoSAR digital beam former. EcoSAR requires two wide P-band antenna arrays mounted on the wings of an aircraft, each capable of steering its main beam up to 35deg off-boresight, allowing the twin radar beams to be steered at angles to the flight path. The science requirements are mainly for dual-polarization capability and a wide bandwidth of operation of up to 200 MHz if possible, but at least 100 MHz with high polarization port isolation and low cross-polarization. The novel design geometry can be scaled with minor modifications up to about four times higher or down to about half the current design frequencies for any application requiring a dual-polarized, wide-bandwidth steerable antenna array. EcoSAR is an airborne interferometric P-band synthetic aperture radar (SAR) research application for studying two- and three-dimensional fine-scale measurements of terrestrial ecosystem structure and biomass, which will ultimately aid in the broader study of the carbon cycle and climate change. The two 2×8 element Pband antenna arrays required by the system will be separated by a baseline of about 25 m, allowing for interferometry measurements. The wide 100-to- 200-MHz bandwidth dual-polarized beams employed will allow the determination of the amount of biomass and even tree height on the ground. To reduce the size of the patches along the boresight dimension in order to fit them into the available space, two techniques were employed. One technique is to add slots along the edges of each patch where the main electric currents are expected to flow, and the other technique is to bend the central part of the patch away from the ground plane. The latter also facilitates higher mechanical rigidity. The high port isolation of more than 40 dB was achieved by employing a highly symmetrical feed mechanism for each

  5. High-resolution adaptive nulling performance for a lightweight agile EHF multiple beam antenna

    NASA Astrophysics Data System (ADS)

    Fenn, A. J.; Johnson, J. R.; Rispin, L. W.; Cummings, W. C.; Potts, B. M.

    The design and experimental performance of a lightweight high-resolution adaptive nulling extremely high-frequency multiple beam antenna (MBA) are addressed. A 127-beam MBA and a four-channel RF nulling network operating over the 43.5-to-45.5-GHz band were used to adaptively null a jammer in anechoic chamber measurements. Lightweight waveguide transmission lines together with ferrite switches were used to select beam ports from the 127-beam MBA. The MBA was designed to provide simultaneous coverage for three communications system users while providing pattern discrimination or nulling of jammers located within 0.1 deg of the user. Cancellation greater than 30 dB when operating in a wideband mode was experimentally demonstrated.

  6. Frequency agile optical parametric oscillator

    DOEpatents

    Velsko, S.P.

    1998-11-24

    The frequency agile OPO device converts a fixed wavelength pump laser beam to arbitrary wavelengths within a specified range with pulse to pulse agility, at a rate limited only by the repetition rate of the pump laser. Uses of this invention include Laser radar, LIDAR, active remote sensing of effluents/pollutants, environmental monitoring, antisensor lasers, and spectroscopy. 14 figs.

  7. Frequency agile optical parametric oscillator

    DOEpatents

    Velsko, Stephan P.

    1998-01-01

    The frequency agile OPO device converts a fixed wavelength pump laser beam to arbitrary wavelengths within a specified range with pulse to pulse agility, at a rate limited only by the repetition rate of the pump laser. Uses of this invention include Laser radar, LIDAR, active remote sensing of effluents/pollutants, environmental monitoring, antisensor lasers, and spectroscopy.

  8. A calibration concept for passive MW imaging using beam steering by frequency shift and aperture synthesis

    NASA Astrophysics Data System (ADS)

    Schreiber, Eric; Peichl, Markus; Jirousek, Matthias

    2013-10-01

    Passive microwave (MW) remote sensing is used in Earth observation missions for example to estimate the salinity of oceans or the soil moisture of landscapes. In these cases the absolute brightness temperature numbers are important for sufficient accuracy of the estimated geo-physical parameters. Consequently a suitable system calibration network is required. At DLR a radiometric demonstrator for fully-electronic MW imaging was set up at Ka-band, which is based on a combination of beam steering by frequency shift using a broadband slotted-waveguide antenna for one scanning direction, and the application of aperture synthesis for the other direction. Aperture synthesis is well known from radio astronomy, but it is still a new imaging principle for Earth observation or security applications. Hence as well new calibration techniques have to be developed for this kind of scanning mechanism. In this paper a novel approach for a noise-source based calibration method taking into account the antenna losses will be introduced. When using aperture synthesis techniques to determine the absolute brightness temperature values, it is very important, among other things, to know the exact phase transfer function of the system in order to achieve the desired radiometric resolution. Consequently our approach enables phase calibration as well. The paper outlines a proof of concept for this calibration method using a two-element interferometer called VESAS (Voll Elektronischer Scanner mit AperturSynthese) as a demonstrator. The functionality of the demonstrator and the proof of concept of the imaging principle mentioned before are written in detail in [1].

  9. Leaky wave antenna with amplitude controlled beam steering based on composite right/left-handed transmission lines

    NASA Astrophysics Data System (ADS)

    Eberspächer, M. A.; Eibert, T. F.

    2010-09-01

    An antenna comprising two different composite right/left-handed transmission line structures is proposed which enables easy beam steering at an operation frequency of 10 GHz. The composite right/left-handed transmission lines are based on planar, periodically arranged via free unit cells, implemented in microstrip technology. Both transmission lines exhibit the infinite wavelength phenomenon which occurs at 9.72 GHz and 9.89 GHz, respectively. Thus, operating the different leaky wave structures at 10 GHz, radiation with azimuth angles of ±8° and ±17° can be achieved depending on the selected input port. In order to obtain a tunable main beam direction, the radiation patterns of both structures are superimposed by feeding them simultaneously. The influence of each guiding structure, and hence the direction of the main beam, can be controlled via the feeding amplitude. As a result of this, the beam can be steered between ±17° with a gain of up to 10 dBi. The guiding structures are arranged in parallel with a clearance of a=12.2 mm which is less than half of the wavelength in free space. This allows in a further step the attachment of additional guiding structures in order to increase the tunable angle range or creating an antenna array with a small beamwidth in the elevation plane without the occurrence of grating lobes. An antenna prototype was fabricated and validated by measurements.

  10. Multi-image acquisition-based distance sensor using agile laser spot beam.

    PubMed

    Riza, Nabeel A; Amin, M Junaid

    2014-09-01

    We present a novel laser-based distance measurement technique that uses multiple-image-based spatial processing to enable distance measurements. Compared with the first-generation distance sensor using spatial processing, the modified sensor is no longer hindered by the classic Rayleigh axial resolution limit for the propagating laser beam at its minimum beam waist location. The proposed high-resolution distance sensor design uses an electronically controlled variable focus lens (ECVFL) in combination with an optical imaging device, such as a charged-coupled device (CCD), to produce and capture different laser spot size images on a target with these beam spot sizes different from the minimal spot size possible at this target distance. By exploiting the unique relationship of the target located spot sizes with the varying ECVFL focal length for each target distance, the proposed distance sensor can compute the target distance with a distance measurement resolution better than the axial resolution via the Rayleigh resolution criterion. Using a 30 mW 633 nm He-Ne laser coupled with an electromagnetically actuated liquid ECVFL, along with a 20 cm focal length bias lens, and using five spot images captured per target position by a CCD-based Nikon camera, a proof-of-concept proposed distance sensor is successfully implemented in the laboratory over target ranges from 10 to 100 cm with a demonstrated sub-cm axial resolution, which is better than the axial Rayleigh resolution limit at these target distances. Applications for the proposed potentially cost-effective distance sensor are diverse and include industrial inspection and measurement and 3D object shape mapping and imaging.

  11. Individual addressing of trapped {sup 171}Yb{sup +} ion qubits using a microelectromechanical systems-based beam steering system

    SciTech Connect

    Crain, S.; Mount, E.; Baek, S.; Kim, J.

    2014-11-03

    The ability to individually manipulate the increasing number of qubits is one of the many challenges towards scalable quantum information processing with trapped ions. Using micro-mirrors fabricated with micro-electromechanical systems technology, we focus laser beams on individual ions in a linear chain and steer the focal point in two dimensions. We demonstrate sequential single qubit gates on multiple {sup 171}Yb{sup +} qubits and characterize the gate performance using quantum state tomography. Our system features negligible crosstalk to neighboring ions (<3×10{sup −4}), and switching speed comparable to typical single qubit gate times (<2 μs)

  12. Design and Performance Evaluation of Optical Ethernet Switching Architecture with Liquid Crystal on Silicon-Based Beam-Steering Technology

    NASA Astrophysics Data System (ADS)

    Cheng, Yuh-Jiuh; Chou, H.-H.; Shiau, Yhi; Cheng, Shu-Ying

    2016-07-01

    A non-blocking optical Ethernet switching architecture with liquid crystal on a silicon-based beam-steering switch and optical output buffer strategies are proposed. For preserving service packet sequencing and fairness of routing sequence, priority and round-robin algorithms are adopted at the optical output buffer in this research. Four methods were used to implement tunable fiber delay modules for the optical output buffers to handle Ethernet packets with variable bit-rates. The results reported are based on the simulations performed to evaluate the proposed switching architecture with traffic analysis under a traffic model captured from a real-core network.

  13. Motion control of the wedge prisms in Risley-prism-based beam steering system for precise target tracking.

    PubMed

    Zhou, Yuan; Lu, Yafei; Hei, Mo; Liu, Guangcan; Fan, Dapeng

    2013-04-20

    Two exact inverse solutions of Risley prisms have been given by previous authors, based on which we calculate the gradients of the scan field that open a way to investigate the nonlinear relationship between the slewing rate of the beam and the required angular velocities of the two wedge prisms in the Risley-prism-based beam steering system for target tracking. The limited regions and singularity point at the center and the edge of the field of regard are discussed. It is found that the maximum required rotational velocities of the two prisms for target tracking are nearly the same and are dependent on the altitude angle. The central limited region is almost independent of the prism parameters. The control singularity at the crossing center path can be avoided by switching the two solutions.

  14. Agile Walker.

    PubMed

    Katz, Reuven

    2015-01-01

    The goal of the Agile Walker is to improve the outdoor mobility of healthy elderly people with some mobility limitations. It is a newly developed, all-terrain walker, equipped with an electric drive system and speed control that can assists elderly people to walk outdoors or to hike. The walker has a unique product design with an attractive look that will appeal to "active-agers" population. This paper describes product design requirements and the development process of the Agile Walker, its features and some preliminary testing results.

  15. Method of achieving ultra-wideband true-time-delay beam steering for active electronically scanned arrays

    DOEpatents

    Loui, Hung; Brock, Billy C.

    2016-10-25

    The various embodiments presented herein relate to beam steering an array antenna by modifying intermediate frequency (IF) waveforms prior to conversion to RF signals. For each channel, a direct digital synthesis (DDS) component can be utilized to generate a waveform or modify amplitude, timing and phase of a waveform relative to another waveform, whereby the generation/modification can be performed prior to the IF input port of a mixer on each channel. A local oscillator (LO) signal can be utilized to commonly drive each of the mixers. After conversion at the RF output port of each of the mixers, each RF signal can be transmitted by a respective antenna element in the antenna array. Initiation of transmission of each RF signal can be performed simultaneously at each antenna. The process can be reversed during receive whereby timing, amplitude, and phase of the received can be modified digitally post ADC conversion.

  16. Investigation of beam steering performances in rotation Risley-prism scanner.

    PubMed

    Li, Anhu; Sun, Wansong; Yi, Wanli; Zuo, Qiyou

    2016-06-13

    Rotation Risley-prism scanner appears to be the most promising solution to high-accuracy beam scanning and target tracking. In the paper, some important issues crucial to the function implementation are thoroughly investigated. First the forming law of scan blind zone relative to double-prism structural parameters is explored by a quantitative analysis method. Then the nonlinear relationship between the rotation speeds of double prisms and the change rate of beam deviation angle is presented, and the beam scan singularity is indicated as an essential factor that confines the beam scan region. Finally, the high-accuracy radial scan theory is verified to illustrate the important application owing to the high reduction ratio from the rotation angles of double prisms to the deviation angles of the emergent beam. The research not only reveals the inner mechanisms of the Risley-prism beam scanning in principle, but also provide a foundation for the nonlinear control of various beam scan modes. PMID:27410303

  17. High efficiency gratings for beam steering on the National Ignition Facility (NIF) laser

    SciTech Connect

    Perry, M.D.; Dixit, S.N.; Shore, B.W.; Boyd, R.D.; Britten, J.A.; Powell, H.T.

    1995-05-26

    The design of the National Ignition Facility (NIF) is based on conversion of 1.05 {mu}m wavelength light (1{omega}) into third harmonic light (3{omega}) by passage through KDP frequency conversion crystals. It is important for proper coupling of radiation into the targets that the final beam impinging upon the target should have little 1{omega} or 2{omega} light. It is also desirable to avoid direct line-of sight for neutrons between the target and the KDP crystals, in order to prevent damage. These issues can be overcome by employing diffraction gratings immediately before the final NIF focusing lens to direct the 3{omega} beam to the target. A single grating design is highly dispersive, and may introduce intolerable divergence into the beam. In order to overcome this limitation, we propose to use a grating pair. This will provide transverse offset of the beam and eliminate the dispersion while offering several other advantages.

  18. Current Control in ITER Steady State Plasmas With Neutral Beam Steering

    SciTech Connect

    R.V. Budny

    2009-09-10

    Predictions of quasi steady state DT plasmas in ITER are generated using the PTRANSP code. The plasma temperatures, densities, boundary shape, and total current (9 - 10 MA) anticipated for ITER steady state plasmas are specified. Current drive by negative ion neutral beam injection, lower-hybrid, and electron cyclotron resonance are calculated. Four modes of operation with different combinations of current drive are studied. For each mode, scans with the NNBI aimed at differing heights in the plasma are performed to study effects of current control on the q profile. The timeevolution of the currents and q are calculated to evaluate long duration transients. Quasi steady state, strongly reversed q profiles are predicted for some beam injection angles if the current drive and bootstrap currents are sufficiently large.

  19. Real-time two-dimensional beam steering with gate-tunable materials: a theoretical investigation.

    PubMed

    Cheng, Jierong; Jafar-Zanjani, Samad; Mosallaei, Hossein

    2016-08-01

    A leaky-wave antenna is proposed that furnishes two-dimensional (2-D) beam scanning in both elevation and azimuth planes via electrical control in real time, and at a single frequency. The structure consists of a graphene sheet on a metal-backed substrate. The 2-D beam-scanning performance is achieved through the proper biasing configuration of graphene. Traditional pixel-by-pixel electrical control makes the biasing network a huge challenge for chip-scale designs in the terahertz regime and beyond. The method presented here enables dynamic control by applying two groups of one-dimensional biasing on the sides of the sheet. They are orthogonal and decoupled, with one group offering monotonic impedance variation along one direction, and the other sinusoidal impedance modulation along the other direction. The conductivity profile of the graphene sheet for a certain radiation angle, realized by applying proper voltage to each pad underneath the sheet, is determined by a holographic technique and can be reconfigured electronically and desirably. Such innovative biasing design makes real-time control of the beam direction and beamwidth simple and highly integrated. The concept is not limited to graphene-based structures, and can be generalized to any available gate-tunable material system. PMID:27505400

  20. Retro-modulators and fast beam steering for free-space optical communications

    NASA Astrophysics Data System (ADS)

    Chan, Trevor Keith

    Free-space optical (FSO) communications is a means of secure, high bandwidth communication through the use of a modulated laser beam in free-space as the information medium. The chaotic nature of the atmosphere and the motion of the communication nodes make laser alignment a crucial concern. The employment of retro-reflecting modulators makes the bidirectional quality of a communication link into a one sided alignment problem. While there are existing retro-reflecting modulators, their trade-offs create a lack of abilities (such as aperture size, angular range, high modulation speeds, economic viability) which do not fulfill the requirements for certain applications. Also, the beam must be directed towards the intended receiver. Form mobile or scintillated communication links, beam direction must be adaptable in real time. Once again, this area suffers from trade-offs where beamsteering speed is often limited. Research used to mitigate the trade-offs and adapt the devices into viable options for a wider range of applications is explored in this dissertation. Two forms of retro-modulators were explored; a MEMS deformable mirror retro-modulator and a solid silicon retro-modulator that modulated the light by frustrated total internal reflection (FTIR). The MEMS version offered a high speed, scalable, wavelength/angle insensitive retro-modulator which can be massed produced at low cost, while the solid retro-modulator offered a large field of view with low cost as well. Both modulator's design, simulated performances, fabrication and experimental characterization are described in this dissertation. An ultra-fast beamscanner was also designed using 2-dimensional dispersion. By using wavelength switching for directional control, a beamscanner was developed that could switch light faster than pre-existing beamscanners while the beams characteristics (most importantly its aperture) could be freely adjusted by the independent optics. This beamscanner was preceded by our

  1. Dynamic characterization and modelling of a dual-axis beam steering device for performance understanding, optimization and control design

    NASA Astrophysics Data System (ADS)

    Berglund, Martin; Palmer, Kristoffer; Lotfi, Sara; Kratz, Henrik; Thornell, Greger

    2013-04-01

    This paper presents a lumped thermal model of a dual-axis laser micromirror device for beam steering in a free-space optical (FSO) communication system, designed for fractionated spacecraft. An FSO communication system provides several advantages, such as larger bandwidth, smaller size and weight of the communication payload and less power consumption. A dual-axis mirror device is designed and realized using microelectromechanical systems technology. The fabrication is based on a double-sided, bulk micromachining process, where the mirror actuates thermally by joints consisting of v-grooves filled with the SU-8 polymer. The size of the device, consisting of a mirror, which is deflectable versus its frame in one direction, and through deflection of the frame in the other, is 15.4 × 10.4 × 0.3 mm3. In order to further characterize and understand the micromirror device, a Simulink state-space model of the actuator is set up using thermal and mechanical properties from a realized actuator. A deviation of less than 2% between the modelled and measured devices was obtained in an actuating temperature range of 20-200 °C. The model of the physical device was examined by evaluating its performance in vacuum, and by changing physical parameters, such as thickness and material composition. By this, design parameters were evaluated for performance gain and usability. For example, the crosstalk between the two actuators deflecting the mirror along its two axes in atmospheric pressure is projected to go down from 97% to 6% when changing the frame material from silicon to silicon dioxide. A feedback control system was also designed around the model in order to examine the possibility to make a robust control system for the physical device. In conclusion, the model of the actuator presented in this paper can be used for further understanding and development of the actuator system.

  2. 20 MHz Forward-imaging Single-element Beam Steering with an Internal Rotating Variable-Angle Reflecting Surface: Wire phantom and Ex vivo pilot study

    PubMed Central

    Raphael, David T.; Li, Xiang; Park, Jinhyoung; Chen, Ruimin; Chabok, Hamid; Barukh, Arthur; Zhou, Qifa; Elgazery, Mahmoud; Shung, K. Kirk

    2012-01-01

    Feasibility is demonstrated for a forward-imaging beam steering system involving a single-element 20 MHz angled-face acoustic transducer combined with an internal rotating variable-angle reflecting surface (VARS). Rotation of the VARS structure, for a fixed position of the transducer, generates a 2-D angular sector scan. If these VARS revolutions were to be accompanied by successive rotations of the single-element transducer, 3-D imaging would be achieved. In the design of this device, a single-element 20 MHz PMN-PT press-focused angled-face transducer is focused on the circle of midpoints of a micro-machined VARS within the distal end of an endoscope. The 2-D imaging system was tested in water bath experiments with phantom wire structures at a depth of 10 mm, and exhibited an axial resolution of 66 μm and a lateral resolution of 520 μm. Chirp coded excitation was used to enhance the signal-to-noise ratio, and to increase the depth of penetration. Images of an ex vivo cow eye were obtained. This VARS-based approach offers a novel forward-looking beam-steering method, which could be useful in intra-cavity imaging. PMID:23122968

  3. 20 MHz forward-imaging single-element beam steering with an internal rotating variable-angle reflecting surface: Wire phantom and ex vivo pilot study.

    PubMed

    Raphael, David T; Li, Xiang; Park, Jinhyoung; Chen, Ruimin; Chabok, Hamid; Barukh, Arthur; Zhou, Qifa; Elgazery, Mahmoud; Shung, K Kirk

    2013-02-01

    Feasibility is demonstrated for a forward-imaging beam steering system involving a single-element 20MHz angled-face acoustic transducer combined with an internal rotating variable-angle reflecting surface (VARS). Rotation of the VARS structure, for a fixed position of the transducer, generates a 2-D angular sector scan. If these VARS revolutions were to be accompanied by successive rotations of the single-element transducer, 3-D imaging would be achieved. In the design of this device, a single-element 20MHz PMN-PT press-focused angled-face transducer is focused on the circle of midpoints of a micro-machined VARS within the distal end of an endoscope. The 2-D imaging system was tested in water bath experiments with phantom wire structures at a depth of 10mm, and exhibited an axial resolution of 66μm and a lateral resolution of 520μm. Chirp coded excitation was used to enhance the signal-to-noise ratio, and to increase the depth of penetration. Images of an ex vivo cow eye were obtained. This VARS-based approach offers a novel forward-looking beam-steering method, which could be useful in intra-cavity imaging. PMID:23122968

  4. Implementation of a Novel Low-Cost Low-Profile Ku-Band Antenna Array for Single Beam Steering from Space

    NASA Technical Reports Server (NTRS)

    Host, Nicholas K.; Chen, Chi-Chih; Volakis, John L.; Miranda, Felix A.

    2013-01-01

    Phased array antennas afford many advantages over traditional reflector antennas due to their conformality, high aperture efficiency, and unfettered beam steering capability at the price of increased cost and complexity. This paper eliminates the complex and costly array backend via the implementation of a series fed array employing a propagation constant reconfigurable transmission line connecting each element in series. Scanning can then be accomplished through one small (less than or equal to 100mil) linear motion that controls propagation constant. Specifically, each element is fed via a reconfigurable coplanar stripline transmission line with a tapered dielectric insert positioned between the transmission line traces. The dielectric insert is allowed to move up and down to control propagation constant and therefore induce scanning. We present a 20 element patch array design, scanning from -25 deg. less than or equal to theta less than or equal to 21 deg. at 13GHz. Measurements achieve only10.5 deg. less than or equal to theta less than or equal to 22 deg. scanning due to a faulty, yet correctable, manufacturing process. Beam squint is measured to be plus or minus 3 deg. for a 600MHz bandwidth. This prototype was improved to give scanning of 3.5 deg. less than or equal to theta less than or equal to 22 deg. Cross-pol patterns were shown to be -15dB below the main beam. Simulations accounting for fabrication errors match measured patterns, thus validating the designs.

  5. Agile Software Development

    ERIC Educational Resources Information Center

    Biju, Soly Mathew

    2008-01-01

    Many software development firms are now adopting the agile software development method. This method involves the customer at every level of software development, thus reducing the impact of change in the requirement at a later stage. In this article, the principles of the agile method for software development are explored and there is a focus on…

  6. Infrared Risley beam pointer

    NASA Astrophysics Data System (ADS)

    Harford, Steven T.; Gutierrez, Homero; Newman, Michael; Pierce, Robert; Quakenbush, Tim; Wallace, John; Bornstein, Michael

    2014-03-01

    Ball Aerospace & Technologies Corp. (BATC) has developed a Risley Beam Pointer (RBP) mechanism capable of agile slewing, accurate pointing and high bandwidth. The RBP is comprised of two wedged prisms that offer a wide Field of Regard (FOR) and may be manufactured and operated with diffraction limited optical quality. The tightly packaged mechanism is capable of steering a 4 inch beam over a 60° half angle cone with better than 60 μrad precision. Absolute accuracy of the beam steering is better than 1 mrad. The conformal nature of the RBP makes it an ideal mechanism for use on low altitude aircraft and unmanned aerial vehicles. Unique aspects of the opto-mechanical design include i) thermal compliance to maintain bearing preload and optical figure over a wide temperature range; and ii) packaging of a remote infrared sensor that periodically reports the temperature of both prisms for accurate determination of the index of refraction. The pointing control system operates each prism independently and employs an inner rate loop nested within an outer position loop. Mathematics for the transformation between line-of-sight coordinates and prism rotation are hosted on a 200 MHz microcontroller with just 516 KB of RAM.

  7. Full correction for spatially distributed speed-of-sound in echo ultrasound based on measuring aberration delays via transmit beam steering.

    PubMed

    Jaeger, Michael; Robinson, Elise; Akarçay, H Günhan; Frenz, Martin

    2015-06-01

    Aberrations of the acoustic wave front, caused by spatial variations of the speed-of-sound, are a main limiting factor to the diagnostic power of medical ultrasound imaging. If not accounted for, aberrations result in low resolution and increased side lobe level, over all reducing contrast in deep tissue imaging. Various techniques have been proposed for quantifying aberrations by analysing the arrival time of coherent echoes from so-called guide stars or beacons. In situations where a guide star is missing, aperture-based techniques may give ambiguous results. Moreover, they are conceptually focused on aberrators that can be approximated as a phase screen in front of the probe. We propose a novel technique, where the effect of aberration is detected in the reconstructed image as opposed to the aperture data. The varying local echo phase when changing the transmit beam steering angle directly reflects the varying arrival time of the transmit wave front. This allows sensing the angle-dependent aberration delay in a spatially resolved way, and thus aberration correction for a spatially distributed volume aberrator. In phantoms containing a cylindrical aberrator, we achieved location-independent diffraction-limited resolution as well as accurate display of echo location based on reconstructing the speed-of-sound spatially resolved. First successful volunteer results confirm the clinical potential of the proposed technique. PMID:25989072

  8. Full correction for spatially distributed speed-of-sound in echo ultrasound based on measuring aberration delays via transmit beam steering

    NASA Astrophysics Data System (ADS)

    Jaeger, Michael; Robinson, Elise; Günhan Akarçay, H.; Frenz, Martin

    2015-06-01

    Aberrations of the acoustic wave front, caused by spatial variations of the speed-of-sound, are a main limiting factor to the diagnostic power of medical ultrasound imaging. If not accounted for, aberrations result in low resolution and increased side lobe level, over all reducing contrast in deep tissue imaging. Various techniques have been proposed for quantifying aberrations by analysing the arrival time of coherent echoes from so-called guide stars or beacons. In situations where a guide star is missing, aperture-based techniques may give ambiguous results. Moreover, they are conceptually focused on aberrators that can be approximated as a phase screen in front of the probe. We propose a novel technique, where the effect of aberration is detected in the reconstructed image as opposed to the aperture data. The varying local echo phase when changing the transmit beam steering angle directly reflects the varying arrival time of the transmit wave front. This allows sensing the angle-dependent aberration delay in a spatially resolved way, and thus aberration correction for a spatially distributed volume aberrator. In phantoms containing a cylindrical aberrator, we achieved location-independent diffraction-limited resolution as well as accurate display of echo location based on reconstructing the speed-of-sound spatially resolved. First successful volunteer results confirm the clinical potential of the proposed technique.

  9. Mechanical 144 GHz beam steering with all-metallic epsilon-near-zero lens antenna

    SciTech Connect

    Pacheco-Peña, V. Torres, V. Orazbayev, B. Beruete, M. Sorolla, M.; Navarro-Cía, M.; Engheta, N.

    2014-12-15

    An all-metallic steerable beam antenna composed of an ε-near-zero (ENZ) metamaterial lens is experimentally demonstrated at 144 GHz (λ{sub 0} = 2.083 mm). The ENZ lens is realized by an array of narrow hollow rectangular waveguides working just near and above the cut-off of the TE{sub 10} mode. The lens focal arc on the xz-plane is initially estimated analytically as well as numerically and compared with experimental results demonstrating good agreement. Next, a flange-ended WR-6.5 waveguide is placed along the lens focal arc to evaluate the ENZ-lens antenna steerability. A gain scan loss below 3 dB is achieved for angles up to ±15°.

  10. Plasma density from Cerenkov radiation, betatron oscillations, and beam steering in a plasma wakefield experiment at 30 GeV

    SciTech Connect

    Catravas, P.; Chattopadhyay, S.; Esarey, E.; Leemans, W.P.; Assmann, R.; Decker, F.-J.; Hogan, M.J.; Iverson, R.; Siemann, R.H.; Walz, D.; Whittum, D.; Blue, B.; Clayton, C.; Joshi, C.; Marsh, K.; Mori, W.B.; Wang, S.; Katsouleas, T.; Lee, S.; Muggli, P.

    2001-01-01

    A method for using Cerenkov radiation near atomic spectral lines to measure plasma source properties for plasma wakefield applications has been discussed and experimentally verified. Because the radiation co-propagates with the electron beam, the radiation samples the source properties exactly along the path of interest with perfect temporal synchronization. Observation wavelengths were chosen with respect to the atomic resonances of the plasma source, where the relative change in the index of refraction strongly affects the Cerenkov cone angle, and permits flexible diagnostic design. The Cerenkov spatial profiles were systematically studied for a Lithium heat pipe oven as a function of oven temperature and observation wavelength. Neutral densities and plasma densities were extracted from the measurements.

  11. An agile implementation of SCRUM

    NASA Astrophysics Data System (ADS)

    Gannon, Michele

    Is Agile a way to cut corners? To some, the use of an Agile Software Development Methodology has a negative connotation - “ Oh, you're just not producing any documentation” . So can a team with no experience in Agile successfully implement and use SCRUM?

  12. Strategic agility for nursing leadership.

    PubMed

    Shirey, Maria R

    2015-06-01

    This department highlights change management strategies that may be successful in strategically planning and executing organizational change. In this article, the author discusses strategic agility as an important leadership competency and offers approaches for incorporating strategic agility in healthcare systems. A strategic agility checklist and infrastructure-building approach are presented. PMID:26010278

  13. Strategic agility for nursing leadership.

    PubMed

    Shirey, Maria R

    2015-06-01

    This department highlights change management strategies that may be successful in strategically planning and executing organizational change. In this article, the author discusses strategic agility as an important leadership competency and offers approaches for incorporating strategic agility in healthcare systems. A strategic agility checklist and infrastructure-building approach are presented.

  14. Studies of pointing, acquisition, and tracking of agile optical wireless transceivers for free-space optical communication networks

    NASA Astrophysics Data System (ADS)

    Ho, Tzung-Hsien; Trisno, Sugianto; Smolyaninov, Igor I.; Milner, Stuart D.; Davis, Christopher C.

    2004-02-01

    Free space, dynamic, optical wireless communications will require topology control for optimization of network performance. Such networks may need to be configured for bi- or multiple-connectedness, reliability and quality-of-service. Topology control involves the introduction of new links and/or nodes into the network to achieve such performance objectives through autonomous reconfiguration as well as precise pointing, acquisition, tracking, and steering of laser beams. Reconfiguration may be required because of link degradation resulting from obscuration or node loss. As a result, the optical transceivers may need to be re-directed to new or existing nodes within the network and tracked on moving nodes. The redirection of transceivers may require operation over a whole sphere, so that small-angle beam steering techniques cannot be applied. In this context, we are studying the performance of optical wireless links using lightweight, bi-static transceivers mounted on high-performance stepping motor driven stages. These motors provide an angular resolution of 0.00072 degree at up to 80,000 steps per second. This paper focuses on the performance characteristics of these agile transceivers for pointing, acquisition, and tracking (PAT), including the influence of acceleration/deceleration time, motor angular speed, and angular re-adjustment, on latency and packet loss in small free space optical (FSO) wireless test networks.

  15. Creating IT agility.

    PubMed

    Glaser, John

    2008-04-01

    Seven steps healthcare organizations can take to improve IT agility are: Pay attention to the capabilities of IT applications. Establish short project phases. Stage the release of capital and new IT positions. Cross-train IT staff. Adopt technology standards. Shorten IT plan time horizons. Align IT with organizational strategies and priorities.

  16. On the suitability of Elekta’s Agility 160 MLC for tracked radiation delivery: closed-loop machine performance

    NASA Astrophysics Data System (ADS)

    Glitzner, M.; Crijns, S. P. M.; de Senneville, B. Denis; Lagendijk, J. J. W.; Raaymakers, B. W.

    2015-03-01

    For motion adaptive radiotherapy, dynamic multileaf collimator tracking can be employed to reduce treatment margins by steering the beam according to the organ motion. The Elekta Agility 160 MLC has hitherto not been evaluated for its tracking suitability. Both dosimetric performance and latency are key figures and need to be assessed generically, independent of the used motion sensor. In this paper, we propose the use of harmonic functions directly fed to the MLC to determine its latency during continuous motion. Furthermore, a control variable is extracted from a camera system and fed to the MLC. Using this setup, film dosimetry and subsequent γ statistics are performed, evaluating the response when tracking (MRI)-based physiologic motion in a closed-loop. The delay attributed to the MLC itself was shown to be a minor contributor to the overall feedback chain as compared to the impact of imaging components such as MRI sequences. Delay showed a linear phase behaviour of the MLC employed in continuously dynamic applications, which enables a general MLC-characterization. Using the exemplary feedback chain, dosimetry showed a vast increase in pass rate employing γ statistics. In this early stage, the tracking performance of the Agility using the test bench yielded promising results, making the technique eligible for translation to tracking using clinical imaging modalities.

  17. Perspectives on Agile Coaching

    NASA Astrophysics Data System (ADS)

    Fraser, Steven; Lundh, Erik; Davies, Rachel; Eckstein, Jutta; Larsen, Diana; Vilkki, Kati

    There are many perspectives to agile coaching including: growing coaching expertise, selecting the appropriate coach for your context; and eva luating value. A coach is often an itinerant who may observe, mentor, negotiate, influence, lead, and/or architect everything from team organization to system architecture. With roots in diverse fields ranging from technology to sociology coaches have differing motivations and experience bases. This panel will bring together coaches to debate and discuss various perspectives on agile coaching. Some of the questions to be addressed will include: What are the skills required for effective coaching? What should be the expectations for teams or individu als being coached? Should coaches be: a corporate resource (internal team of consultants working with multiple internal teams); an integral part of a specific team; or external contractors? How should coaches exercise influence and au thority? How should management assess the value of a coaching engagement? Do you have what it takes to be a coach? - This panel will bring together sea soned agile coaches to offer their experience and advice on how to be the best you can be!

  18. Agile Infrastructure Monitoring

    NASA Astrophysics Data System (ADS)

    Andrade, P.; Ascenso, J.; Fedorko, I.; Fiorini, B.; Paladin, M.; Pigueiras, L.; Santos, M.

    2014-06-01

    At the present time, data centres are facing a massive rise in virtualisation and cloud computing. The Agile Infrastructure (AI) project is working to deliver new solutions to ease the management of CERN data centres. Part of the solution consists in a new "shared monitoring architecture" which collects and manages monitoring data from all data centre resources. In this article, we present the building blocks of this new monitoring architecture, the different open source technologies selected for each architecture layer, and how we are building a community around this common effort.

  19. Agile Walking Robot

    NASA Technical Reports Server (NTRS)

    Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.; Waldron, Kenneth J.

    1990-01-01

    Proposed agile walking robot operates over rocky, sandy, and sloping terrain. Offers stability and climbing ability superior to other conceptual mobile robots. Equipped with six articulated legs like those of insect, continually feels ground under leg before applying weight to it. If leg sensed unexpected object or failed to make contact with ground at expected point, seeks alternative position within radius of 20 cm. Failing that, robot halts, examines area around foot in detail with laser ranging imager, and replans entire cycle of steps for all legs before proceeding.

  20. Monogamy of quantum steering

    NASA Astrophysics Data System (ADS)

    Milne, Antony; Jennings, David; Jevtic, Sania; Rudolph, Terry; Wiseman, Howard

    The quantum steering ellipsoid formalism naturally extends the Bloch vector picture for qubits to provide a visualisation of two-qubit systems. If Alice and Bob share a correlated state then a local measurement by Bob steers Alice's qubit inside the Bloch sphere; given all possible measurements by Bob, the set of states to which Alice can be steered form her steering ellipsoid. We apply the formalism to a three-party scenario and find that steering ellipsoid volumes obey a simple monogamy relation. This gives us a novel derivation of the well-known CKW (Coffman-Kundu-Wootters) inequality for entanglement monogamy. The geometric perspective also identifies a new measure of quantum correlation, `obesity', and a set of `maximally obese' states that saturate the steering monogamy bound. These states are found to have extremal quantum correlation properties that are significant in the steering ellipsoid picture and for the study of two-qubit states in general.

  1. Multipass Steering: A Reference Implementation

    NASA Astrophysics Data System (ADS)

    Hennessey, Michael; Tiefenback, Michael

    2015-10-01

    We introduce a reference implementation of a protocol to compute corrections that bring all beams in one of the CEBAF linear accelerators (linac) to axis, including, with a larger tolerance, the lowest energy pass using measured beam trajectory data. This method relies on linear optics as representation of the system; we treat beamline perturbations as magnetic field errors localized to regions between cryomodules, providing the same transverse momentum kick to each beam. We produce a vector of measured beam position data with which we left-multiply the pseudo-inverse of a coefficient array, A, that describes the transport of the beam through the linac using parameters that include the magnetic offsets of the quadrupole magnets, the instrumental offsets of the BPMs, and the beam initial conditions. This process is repeated using a reduced array to produce values that can be applied to the available correcting magnets and beam initial conditions. We show that this method is effective in steering the beam to a straight axis along the linac by using our values in elegant, the accelerator simulation program, on a model of the linac in question. The algorithms in this reference implementation provide a tool for systematic diagnosis and cataloging of perturbations in the beam line. Supported by Jefferson Lab, Old Dominion University, NSF, DOE.

  2. Multipass Steering Protocols at Jefferson Lab

    SciTech Connect

    Ryan Bodenstein; Michael Tiefenback

    2007-06-22

    The CEBAF recirculating accelerator consists of two CW superconducting RF linacs, through which an electron beam is accelerated for up to 5 passes. Focusing and steering elements affect each pass differently, requiring a multipass steering protocol to correct the orbits. Perturbations include lens misalignments (including long-term ground motion), BPM offsets, and focusing and steering from RF fields inside the cavities. A previous treatment of this problem assumed all perturbations were localized at the quadrupoles and the absence of x-y coupling. Having analyzed the problem and characterized the solutions, we developed an empirical iterative protocol to compare against previous results in the presence of skew fields and cross-plane coupling. We plan to characterize static and acceleration-dependent components of the beam line perturbations to allow systematic and rapid configuration of the accelerator at different linac energy gains.

  3. Agile manufacturing concept

    NASA Astrophysics Data System (ADS)

    Goldman, Steven L.

    1994-03-01

    The initial conceptualization of agile manufacturing was the result of a 1991 study -- chaired by Lehigh Professor Roger N. Nagel and California-based entrepreneur Rick Dove, President of Paradigm Shifts, International -- of what it would take for U.S. industry to regain global manufacturing competitiveness by the early twenty-first century. This industry-led study, reviewed by senior management at over 100 companies before its release, concluded that incremental improvement of the current system of manufacturing would not be enough to be competitive in today's global marketplace. Computer-based information and production technologies that were becoming available to industry opened up the possibility of an altogether new system of manufacturing, one that would be characterized by a distinctive integration of people and technologies; of management and labor; of customers, producers, suppliers, and society.

  4. Aircraft agility maneuvers

    NASA Technical Reports Server (NTRS)

    Cliff, Eugene M.; Thompson, Brian G.

    1992-01-01

    A new dynamic model for aircraft motions is presented. This model can be viewed as intermediate between a point-mass model, in which the body attitude angles are control-like, and a rigid-body model, in which the body-attitude angles evolve according to Newton's Laws. Specifically, consideration is given to the case of symmetric flight, and a model is constructed in which the body roll-rate and the body pitch-rate are the controls. In terms of this body-rate model a minimum-time heading change maneuver is formulated. When the bounds on the body-rates are large the results are similar to the point-mass model in that the model can very quickly change the applied forces and produce an acceleration to turn the vehicle. With finite bounds on these rates, the forces change in a smooth way. This leads to a measurable effect of agility.

  5. Elements of an Art - Agile Coaching

    NASA Astrophysics Data System (ADS)

    Lundh, Erik

    This tutorial gives you a lead on becoming or redefining yourself as an Agile Coach. Introduction to elements and dimensions of state-of-the-art Agile Coaching. How to position the agile coach to be effective in a larger setting. Making the agile transition - from a single team to thousands of people. How to support multiple teams as a coach. How to build a coaches network in your company. Challenges when the agile coach is a consultant and the organization is large.

  6. The Telemetry Agile Manufacturing Effort

    SciTech Connect

    Brown, K.D.

    1995-01-01

    The Telemetry Agile Manufacturing Effort (TAME) is an agile enterprising demonstration sponsored by the US Department of Energy (DOE). The project experimented with new approaches to product realization and assessed their impacts on performance, cost, flow time, and agility. The purpose of the project was to design the electrical and mechanical features of an integrated telemetry processor, establish the manufacturing processes, and produce an initial production lot of two to six units. This paper outlines the major methodologies utilized by the TAME, describes the accomplishments that can be attributed to each methodology, and finally, examines the lessons learned and explores the opportunities for improvement associated with the overall effort. The areas for improvement are discussed relative to an ideal vision of the future for agile enterprises. By the end of the experiment, the TAME reduced production flow time by approximately 50% and life cycle cost by more than 30%. Product performance was improved compared with conventional DOE production approaches.

  7. Improving Global Development Using Agile

    NASA Astrophysics Data System (ADS)

    Avritzer, Alberto; Bronsard, Francois; Matos, Gilberto

    Global development promises important productivity and capability advantages over centralized work by optimally allocating tasks according to locality, expertise or cost. All too often, global development also introduces a different set of communication and coordination challenges that can negate all the expected benefits and even cause project failures. Most common problems have to do with building trust or quick feedback loops between distributed teams, or with the integration of globally developed components. Agile processes tend to emphasize the intensity of communication, and would seem to be negatively impacted by team distribution. In our experience, these challenges can be overcome, and agile processes can address some of the pitfalls of global development more effectively than plan-driven development. This chapter discusses how to address the difficulties faced when adapting agile processes to global development and the improvements to global development that adopting agile can produce.

  8. Human factors in agile manufacturing

    SciTech Connect

    Forsythe, C.

    1995-03-01

    As industries position themselves for the competitive markets of today, and the increasingly competitive global markets of the 21st century, agility, or the ability to rapidly develop and produce new products, represents a common trend. Agility manifests itself in many different forms, with the agile manufacturing paradigm proposed by the Iacocca Institute offering a generally accepted, long-term vision. In its many forms, common elements of agility or agile manufacturing include: changes in business, engineering and production practices, seamless information flow from design through production, integration of computer and information technologies into all facets of the product development and production process, application of communications technologies to enable collaborative work between geographically dispersed product development team members and introduction of flexible automation of production processes. Industry has rarely experienced as dramatic an infusion of new technologies or as extensive a change in culture and work practices. Human factors will not only play a vital role in accomplishing the technical and social objectives of agile manufacturing. but has an opportunity to participate in shaping the evolution of industry paradigms for the 21st century.

  9. Simultaneous demultiplexing and steering of multiple orbital angular momentum modes

    PubMed Central

    Li, Shuhui; Wang, Jian

    2015-01-01

    We present a simple scheme to perform simultaneous demultiplexing and steering of multiple orbital angular momentum (OAM) modes using a single complex phase mask. By designing the phase mask, the propagation directions of demultiplexed beams can be arbitrarily steered. System experiments using orthogonal frequency-division multiplexing 32-ary quadrature amplitude modulation (OFDM-32QAM) signals over two OAM modes are carried out by using a two-mode complex phase mask. Moreover, demultiplexing of sixteen OAM modes and arbitrary demultiplexed beam steering are also demonstrated in the experiment. PMID:26503167

  10. Automotive power steering system

    SciTech Connect

    VanGorder, D.H.; Wilson, K.R.

    1991-04-23

    This patent describes improvement in an automotive power steering system including a pump, a servo-valve, a steering assist fluid motor, a reservoir having a reservoir chamber therein, fluid ducts; a volume of hydraulic oil; a fluid level. The improvement comprises: means defining a fill port; a cover; means connect a gas accumulator.

  11. SU-E-T-610: Comparison of Treatment Times Between the MLCi and Agility Multileaf Collimators

    SciTech Connect

    Ramsey, C; Bowling, J

    2014-06-01

    Purpose: The Agility is a new 160-leaf MLC developed by Elekta for use in their Infinity and Versa HD linacs. As compared to the MLCi, the Agility increased the maximum leaf speed from 2 cm/s to 3.5 cm/s, and the maximum primary collimator speed from 1.5 cm/s to 9.0 cm/s. The purpose of this study was to determine if the Agility MLC resulted in improved plan quality and/or shorter treatment times. Methods: An Elekta Infinity that was originally equipped with a 80 leaf MLCi was upgraded to an 160 leaf Agility. Treatment plan quality was evaluated using the Pinnacle planning system with SmartArc. Optimization was performed once for the MLCi and once for the Agility beam models using the same optimization parameters and the same number of iterations. Patient treatment times were measured for all IMRT, VMAT, and SBRT patients treated on the Infinity with the MLCi and Agility MLCs. Treatment times were extracted from the EMR and measured from when the patient first walked into the treatment room until exiting the treatment room. Results: 11,380 delivery times were measured for patients treated with the MLCi, and 1,827 measurements have been made for the Agility MLC. The average treatment times were 19.1 minutes for the MLCi and 20.8 minutes for the Agility. Using a t-test analysis, there was no difference between the two groups (t = 0.22). The dose differences between patients planned with the MLCi and the Agility MLC were minimal. For example, the dose difference for the PTV, GTV, and cord for a head and neck patient planned using Pinnacle were effectively equivalent. However, the dose to the parotid glands was slightly worse with the Agility MLC. Conclusion: There was no statistical difference in treatment time, or any significant dosimetric difference between the Agility MLC and the MLCi.

  12. What Does an Agile Coach Do?

    NASA Astrophysics Data System (ADS)

    Davies, Rachel; Pullicino, James

    The surge in Agile adoption has created a demand for project managers rather than direct their teams. A sign of this trend is the ever-increasing number of people getting certified as scrum masters and agile leaders. Training courses that introduce agile practices are easy to find. But making the transition to coach is not as simple as understanding what agile practices are. Your challenge as an Agile Coach is to support your team in learning how to wield their new Agile tools in creating great software.

  13. Piloted simulator assessments of agility

    NASA Technical Reports Server (NTRS)

    Schneider, Edward T.

    1990-01-01

    NASA has utilized piloted simulators for nearly two decades to study high-angle-of-attack flying qualities, agility, and air-to-air combat. These studies have included assessments of an F-16XL aircraft equipped with thrust vectoring, an assessment of the F-18 HARV maneuvering requirements to assist in thrust vectoring control system design, and an agility assessment of the F-18. The F-18 agility assessment was compared with in-flight testing. Open-loop maneuvers such as 180-deg rolls to measure roll rate showed favorable simulator/in-flight comparison. Closed-loop maneuvers such as rolls to 90 deg with precision stops or certain maximum longitudinal pitching maneuvers showed poorer performance due to reduced aggressiveness of pilot inputs in flight to remain within flight envelope limits.

  14. Fermilab Steering Group Report

    SciTech Connect

    Steering Group, Fermilab; /Fermilab

    2007-12-01

    The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOvA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building an intense proton facility, Project X, consisting of a linear accelerator with the currently planned characteristics of the ILC combined with Fermilab's existing Recycler Ring and the Main Injector accelerator. The major component of Project X is the linac. Cryomodules, radio-frequency distribution, cryogenics and instrumentation for the linac are the same as or similar to those used in the ILC at a scale of about one percent of a full ILC linac. Project X's intense proton beams would open a path to discovery in neutrino science and in precision physics with charged leptons and quarks. World-leading experiments would allow physicists to address key questions of the Quantum Universe: How did the universe come to be? Are there undiscovered principles of nature: new symmetries, new physical laws? Do all the particles and forces become one? What happened to the antimatter? Building Project X's ILC-like linac would offer substantial support for ILC development by accelerating the industrialization of ILC components

  15. Fermilab Steering Group Report

    SciTech Connect

    Beier, Eugene; Butler, Joel; Dawson, Sally; Edwards, Helen; Himel, Thomas; Holmes, Stephen; Kim, Young-Kee; Lankford, Andrew; McGinnis, David; Nagaitsev, Sergei; Raubenheimer, Tor; /SLAC /Fermilab

    2007-01-01

    The Fermilab Steering Group has developed a plan to keep U.S. accelerator-based particle physics on the pathway to discovery, both at the Terascale with the LHC and the ILC and in the domain of neutrinos and precision physics with a high-intensity accelerator. The plan puts discovering Terascale physics with the LHC and the ILC as Fermilab's highest priority. While supporting ILC development, the plan creates opportunities for exciting science at the intensity frontier. If the ILC remains near the Global Design Effort's technically driven timeline, Fermilab would continue neutrino science with the NOVA experiment, using the NuMI (Neutrinos at the Main Injector) proton plan, scheduled to begin operating in 2011. If ILC construction must wait somewhat longer, Fermilab's plan proposes SNuMI, an upgrade of NuMI to create a more powerful neutrino beam. If the ILC start is postponed significantly, a central feature of the proposed Fermilab plan calls for building an intense proton facility, Project X, consisting of a linear accelerator with the currently planned characteristics of the ILC combined with Fermilab's existing Recycler Ring and the Main Injector accelerator. The major component of Project X is the linac. Cryomodules, radio-frequency distribution, cryogenics and instrumentation for the linac are the same as or similar to those used in the ILC at a scale of about one percent of a full ILC linac. Project X's intense proton beams would open a path to discovery in neutrino science and in precision physics with charged leptons and quarks. World-leading experiments would allow physicists to address key questions of the Quantum Universe: How did the universe come to be? Are there undiscovered principles of nature: new symmetries, new physical laws? Do all the particles and forces become one? What happened to the antimatter? Building Project X's ILC-like linac would offer substantial support for ILC development by accelerating the industrialization of ILC components

  16. Software ``Best'' Practices: Agile Deconstructed

    NASA Astrophysics Data System (ADS)

    Fraser, Steven

    This workshop will explore the intersection of agility and software development in a world of legacy code-bases and large teams. Organizations with hundreds of developers and code-bases exceeding a million or tens of millions of lines of code are seeking new ways to expedite development while retaining and attracting staff who desire to apply “agile” methods. This is a situation where specific agile practices may be embraced outside of their usual zone of applicability. Here is where practitioners must understand both what “best practices” already exist in the organization - and how they might be improved or modified by applying “agile” approaches.

  17. Laser agile illumination for object tracking and classification - Feasibility study

    NASA Technical Reports Server (NTRS)

    Scholl, Marija S.; Vanzyl, Jakob J.; Meinel, Aden B.; Meinel, Marjorie P.; Scholl, James W.

    1988-01-01

    The 'agile illumination' concept for discrimination between ICBM warheads and decoys involves a two-aperture illumination with coherent light, diffraction of light by propagation, and a resulting interference pattern on the object surface. A scanning two-beam interference pattern illuminates one object at a time; depending on the shape, momentum, spinning, and tumbling characteristics of the interrogated object, different temporal signals will be obtained for different classes of objects.

  18. Backwards planning approach for rapid attitude maneuvers steering

    NASA Astrophysics Data System (ADS)

    Verbin, D.

    Remote sensing satellites are often built with payloads that do not include line of sight steering mechanisms. In cases, when frequent line of sight retargeting is required, there is a need for efficient actuators and control schemes that would support rapid attitude manoeuvring together with adequate pointing accuracy and stability between the manoeuvres. Within this frame, this research develops the Backwards Planning approach as one of the possible control methods for rapid manoeuvring. The method is based on state feedback and combines time efficient together with straight forward computation flow. Novel efficient methods to execute the Backwards Planning Control in the 3D attitude space are proposed here. The methods refer both for the first saturated control phase of the manoeuvre and for the last braking phase. The actuators used for the spacecraft control in this research are either Reaction Wheels (RWs) or Single Gimbal Control Moments Gyros (SGCMGs) or both of them together. The advantage of the SGCMG is in rapid rotational manoeuvring, but their application for high quality pointing requires very accurate gimbal mechanisms. On the other hand, RWs are usually more suitable for accurate pointing, but their torque to power performance is inferior in manoeuvring. It is shown that the coordination of SGCMGs and RWs together enables to draw more performance from the SGCMGs in terms of agility and meet the pointing requirements between manoeuvres where only the RWs are used. Novel SGCMG steering laws are suggested as well. While the steering laws determine the required angular rate for each gimbal, most steering laws are defined in the angular momentum domain and output the gimbals angular rates to produce a given required torque or angular momentum increment. This research however, practices a novel steering law in the gimbal angles domain. While both steering laws turn to be dynamically equivalent for small control signals, as in the steady state, it is shown

  19. Steering Law Controlling the Constant Speeds of Control Moment Gyros

    NASA Astrophysics Data System (ADS)

    KOYASAKO, Y.; TAKAHASHI, M.

    2016-09-01

    To enable the agile control of satellites, using control moment gyros (CMGs) has become increasingly necessary because of their ability to generate large amounts of torque. However, CMGs have a singularity problem whereby the torque by the CMGs degenerates from three dimensions to two dimensions, affecting spacecraft attitude control performance. This study proposes a new steering control law for CMGs by controlling the constant speed of a CMG. The proposed method enables agile attitude changes, according to the required task, by managing the total angular momentum of the CMGs by considering the distance to external singularities. In the proposed method, the total angular momentum is biased in a specific direction and the angular momentum envelope is extended. The design method can increase the net angular momentum of CMGs which can be exchanged with the satellite. The effectiveness of the proposed method is demonstrated by numerical simulations.

  20. Charge steering of laser plasma accelerated fast ions in a liquid spray — creation of MeV negative ion and neutral atom beams

    SciTech Connect

    Schnürer, M.; Abicht, F.; Priebe, G.; Braenzel, J.; Prasad, R.; Borghesi, M.; Andreev, A.; Nickles, P. V.; Jequier, S.; Tikhonchuk, V.; Ter-Avetisyan, S.

    2013-11-15

    The scenario of “electron capture and loss” has been recently proposed for the formation of negative ion and neutral atom beams with up to MeV kinetic energy [S. Ter-Avetisyan, et al., Appl. Phys. Lett. 99, 051501 (2011)]. Validation of these processes and of their generic nature is here provided in experiments where the ion source and the interaction medium have been spatially separated. Fast positive ions accelerated from a laser plasma source are sent through a cold spray where their charge is changed. Such formed neutral atom or negative ion has nearly the same momentum as the original positive ion. Experiments are released for protons, carbon, and oxygen ions and corresponding beams of negative ions and neutral atoms have been obtained. The electron capture and loss phenomenon is confirmed to be the origin of the negative ion and neutral atom beams. The equilibrium ratios of different charge components and cross sections have been measured. Our method is general and allows the creation of beams of neutral atoms and negative ions for different species which inherit the characteristics of the positive ion source.

  1. Light steering in a strongly nonlocal nonlinear medium

    SciTech Connect

    Ouyang Shigen; Hu Wei; Guo Qi

    2007-11-15

    With a strongly nonlocal model, we present an analytical solution of the coherent interaction of two Gaussian beams with an arbitrary phase difference and arbitrary incident angles. Numerical simulations show that the analytical solution can describe the interaction of two Gaussian beams very well in the strongly nonlocal case. It is theoretically shown that one can steer lights in strongly nonlocal media by tuning the incident conditions of coherently interacting beams like the phase difference between beams and their relative amplitude.

  2. Wavelength-Agile External-Cavity Diode Laser for DWDM

    NASA Technical Reports Server (NTRS)

    Pilgrim, Jeffrey S.; Bomse, David S.

    2006-01-01

    A prototype external-cavity diode laser (ECDL) has been developed for communication systems utilizing dense wavelength- division multiplexing (DWDM). This ECDL is an updated version of the ECDL reported in Wavelength-Agile External- Cavity Diode Laser (LEW-17090), NASA Tech Briefs, Vol. 25, No. 11 (November 2001), page 14a. To recapitulate: The wavelength-agile ECDL combines the stability of an external-cavity laser with the wavelength agility of a diode laser. Wavelength is modulated by modulating the injection current of the diode-laser gain element. The external cavity is a Littman-Metcalf resonator, in which the zeroth-order output from a diffraction grating is used as the laser output and the first-order-diffracted light is retro-reflected by a cavity feedback mirror, which establishes one end of the resonator. The other end of the resonator is the output surface of a Fabry-Perot resonator that constitutes the diode-laser gain element. Wavelength is selected by choosing the angle of the diffracted return beam, as determined by position of the feedback mirror. The present wavelength-agile ECDL is distinguished by design details that enable coverage of all 60 channels, separated by 100-GHz frequency intervals, that are specified in DWDM standards.

  3. Steering and collimating ballistic electrons with amphoteric refraction

    SciTech Connect

    Radu, A.; Dragoman, D.; Iftimie, S.

    2012-07-15

    We show that amphoteric refraction of ballistic electrons, i.e., positive or negative refraction depending on the incidence angle, occurs at an interface between an isotropic and an anisotropic medium and can be employed to steer and collimate electron beams. The steering angle is determined by the materials' parameters, but the degree of collimation can be tuned in a significant range by changing the energy of ballistic electrons.

  4. 52. Patent steering gear, hatch and steering compass binnacle, view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    52. Patent steering gear, hatch and steering compass binnacle, view from starboard looking aft. Photograph by Jet Lowe, April 1988. - Ship BALCLUTHA, 2905 Hyde Street Pier, San Francisco, San Francisco County, CA

  5. Linac Alignment Algorithm: Analysis on 1-to-1 Steering

    SciTech Connect

    Sun, Yipeng; Adolphsen, Chris; /SLAC

    2011-08-19

    In a linear accelerator, it is important to achieve a good alignment between all of its components (such as quadrupoles, RF cavities, beam position monitors et al.), in order to better preserve the beam quality during acceleration. After the survey of the main linac components, there are several beam-based alignment (BBA) techniques to be applied, to further optimize the beam trajectory and calculate the corresponding steering magnets strength. Among these techniques the most simple and straightforward one is the one-to-one (1-to-1) steering technique, which steers the beam from quad center to center, and removes the betatron oscillation from quad focusing. For a future linear collider such as the International Linear Collider (ILC), the initial beam emittance is very small in the vertical plane (flat beam with {gamma}{epsilon}{sub y} = 20-40nm), which means the alignment requirement is very tight. In this note, we evaluate the emittance growth with one-to-one correction algorithm employed, both analytically and numerically. Then the ILC main linac accelerator is taken as an example to compare the vertical emittance growth after 1-to-1 steering, both from analytical formulae and multi-particle tracking simulation. It is demonstrated that the estimated emittance growth from the derived formulae agrees well with the results from numerical simulation, with and without acceleration, respectively.

  6. Steering in bicycles and motorcycles

    NASA Astrophysics Data System (ADS)

    Fajans, J.

    2000-07-01

    Steering a motorcycle or bicycle is counterintuitive; to turn right, you must steer left initially, and vice versa. You can execute this initially counter-directed turn by turning the handlebars explicitly (called counter-steering) or by throwing your hips to the side. Contrary to common belief, gyroscopic forces play only a limited role in balancing and steering [D. E. H. Jones, Phys. Today 23 (4), 34-40 (1970)].

  7. An Investigation of Agility Issues in Scrum Teams Using Agility Indicators

    NASA Astrophysics Data System (ADS)

    Pikkarainen, Minna; Wang, Xiaofeng

    Agile software development methods have emerged and become increasingly popular in recent years; yet the issues encountered by software development teams that strive to achieve agility using agile methods are yet to be explored systematically. Built upon a previous study that has established a set of indicators of agility, this study investigates what issues are manifested in software development teams using agile methods. It is focussed on Scrum teams particularly. In other words, the goal of the chapter is to evaluate Scrum teams using agility indicators and therefore to further validate previously presented agility indicators within the additional cases. A multiple case study research method is employed. The findings of the study reveal that the teams using Scrum do not necessarily achieve agility in terms of team autonomy, sharing, stability and embraced uncertainty. The possible reasons include previous organizational plan-driven culture, resistance towards the Scrum roles and changing resources.

  8. The AGILE gamma-ray astronomy mission

    NASA Astrophysics Data System (ADS)

    Mereghetti, S.; Tavani, M.; Argan, A.; Barbiellini, G.; Caraveo, P.; Chen, A.; Cocco, V.; Costa, E.; Di Cocco, G.; Feroci, M.; Labanti, C.; Lapshov, I.; Lipari, P.; Longo, F.; Morselli, A.; Perotti, F.; Picozza, P.; Pittori, C.; Prest, M.; Rubini, A.; Soffitta, P.; Vallazza, E.; Vercellone, S.; Zanello, D.

    2001-09-01

    We describe the AGILE satellite: a unique tool for high-energy astrophysics in the 30 MeV - 50 GeV range before GLAST. The scientific performances of AGILE are comparable to those of EGRET, despite the much smaller weight and dimensions. The AGILE mission will be optimized for the imaging capabilities above 30 MeV and for the study of transient phenomena, complemented by simultaneous monitoring in the hard X-ray band (10 - 40 keV).

  9. A Highly Agile Ground Assessment Robot (HAGAR) for military battlefield and support missions

    SciTech Connect

    Klarer, P.

    1994-04-01

    A mobile robotic vehicle with potential for use in military field applications is described. Based on a Sandia design intended for use in exploration of the Lunar surface, the Highly Agile Ground Assessment Robot (HAGAR) is a four wheeled all-wheel-drive dual-body vehicle. A uniquely simple method of chassis articulation is employed which allows all four wheels to remain in contact with the ground, even while operating in very rough terrain and climbing over obstacles as large as a wheel diameter. Skid steering and modular construction are used to produce a simple, rugged, lightweight, highly agile mobility chassis with a reduction in the number of parts required when compared to conventional vehicle designs for military battlefield and support missions. The design configuration, mobility parameters, potential mission configurations, and performance of existing and proposed HAGAR prototypes are discussed.

  10. Mirrors Steer NASA in the Right Direction

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Left Hand Design completed the production of the fine-steering mirror technology through 1995 Phase I and 1996 Phase II SBIR contracts with JPL's Interferometric Astronomy group. Presently, the work resulting from the collaboration with NASA represents the company's main line of products for the commercial sector. Aerospace-related applications include: image motion compensation; interceptor seekers for the U.S. Army and Navy; Earth observation and resource monitoring from spacecraft and airborne platforms; space astronomy; helicopter-based surveillance; and interferometric metrology. Left Hand Design's fine-steering mirrors have also penetrated the commercial marketplace with non-aerospace applications, including laser communications, video cameras, infrared inspection, solar observatories, and bathymeters. These cost-effective, commercial mirrors perform a variety of functions, such as scanning, alignment, chopping, tracking, pointing, and beam stabilization. Potential future applications include laser surgery and photolithography.

  11. Multiply-agile encryption in high speed communication networks

    SciTech Connect

    Pierson, L.G.; Witzke, E.L.

    1997-05-01

    Different applications have different security requirements for data privacy, data integrity, and authentication. Encryption is one technique that addresses these requirements. Encryption hardware, designed for use in high-speed communications networks, can satisfy a wide variety of security requirements if that hardware is key-agile, robustness-agile and algorithm-agile. Hence, multiply-agile encryption provides enhanced solutions to the secrecy, interoperability and quality of service issues in high-speed networks. This paper defines these three types of agile encryption. Next, implementation issues are discussed. While single-algorithm, key-agile encryptors exist, robustness-agile and algorithm-agile encryptors are still research topics.

  12. The GLAST-AGILE Support Program (GASP)

    NASA Astrophysics Data System (ADS)

    Villata, M.; Raiteri, C. M.; Webt Collaboration

    2008-10-01

    The GLAST-AGILE Support Program (GASP) was organized within the Whole Earth Blazar Telescope to provide optical-to-radio long-term continuous monitoring of a list of selected gamma-ray-loud blazars during the operation of the AGILE and GLAST satellites. We present some results obtained since its birth, in September 2007.

  13. Teaching Agile Software Development: A Case Study

    ERIC Educational Resources Information Center

    Devedzic, V.; Milenkovic, S. R.

    2011-01-01

    This paper describes the authors' experience of teaching agile software development to students of computer science, software engineering, and other related disciplines, and comments on the implications of this and the lessons learned. It is based on the authors' eight years of experience in teaching agile software methodologies to various groups…

  14. An Agile Course-Delivery Approach

    ERIC Educational Resources Information Center

    Capellan, Mirkeya

    2009-01-01

    In the world of software development, agile methodologies have gained popularity thanks to their lightweight methodologies and flexible approach. Many advocates believe that agile methodologies can provide significant benefits if applied in the educational environment as a teaching method. The need for an approach that engages and motivates…

  15. The Introduction of Agility into Albania.

    ERIC Educational Resources Information Center

    Smith-Stevens, Eileen J.; Shkurti, Drita

    1998-01-01

    Describes a plan to introduce and achieve a national awareness of agility (and easy entry into the world market) for Albania through the relatively stable higher-education order. Agility's four strategic principles are enriching the customer, cooperating to enhance competitiveness, organizing to master change and uncertainty, and leveraging the…

  16. Some Findings Concerning Requirements in Agile Methodologies

    NASA Astrophysics Data System (ADS)

    Rodríguez, Pilar; Yagüe, Agustín; Alarcón, Pedro P.; Garbajosa, Juan

    Agile methods have appeared as an attractive alternative to conventional methodologies. These methods try to reduce the time to market and, indirectly, the cost of the product through flexible development and deep customer involvement. The processes related to requirements have been extensively studied in literature, in most cases in the frame of conventional methods. However, conclusions of conventional methodologies could not be necessarily valid for Agile; in some issues, conventional and Agile processes are radically different. As recent surveys report, inadequate project requirements is one of the most conflictive issues in agile approaches and better understanding about this is needed. This paper describes some findings concerning requirements activities in a project developed under an agile methodology. The project intended to evolve an existing product and, therefore, some background information was available. The major difficulties encountered were related to non-functional needs and management of requirements dependencies.

  17. Agile manufacturing from a statistical perspective

    SciTech Connect

    Easterling, R.G.

    1995-10-01

    The objective of agile manufacturing is to provide the ability to quickly realize high-quality, highly-customized, in-demand products at a cost commensurate with mass production. More broadly, agility in manufacturing, or any other endeavor, is defined as change-proficiency; the ability to thrive in an environment of unpredictable change. This report discusses the general direction of the agile manufacturing initiative, including research programs at the National Institute of Standards and Technology (NIST), the Department of Energy, and other government agencies, but focuses on agile manufacturing from a statistical perspective. The role of statistics can be important because agile manufacturing requires the collection and communication of process characterization and capability information, much of which will be data-based. The statistical community should initiate collaborative work in this important area.

  18. Agile manufacturing prototyping system (AMPS)

    SciTech Connect

    Garcia, P.

    1998-05-09

    The Agile Manufacturing Prototyping System (AMPS) is being integrated at Sandia National Laboratories. AMPS consists of state of the industry flexible manufacturing hardware and software enhanced with Sandia advancements in sensor and model based control; automated programming, assembly and task planning; flexible fixturing; and automated reconfiguration technology. AMPS is focused on the agile production of complex electromechanical parts. It currently includes 7 robots (4 Adept One, 2 Adept 505, 1 Staubli RX90), conveyance equipment, and a collection of process equipment to form a flexible production line capable of assembling a wide range of electromechanical products. This system became operational in September 1995. Additional smart manufacturing processes will be integrated in the future. An automated spray cleaning workcell capable of handling alcohol and similar solvents was added in 1996 as well as parts cleaning and encapsulation equipment, automated deburring, and automated vision inspection stations. Plans for 1997 and out years include adding manufacturing processes for the rapid prototyping of electronic components such as soldering, paste dispensing and pick-and-place hardware.

  19. CT-assisted agile manufacturing

    NASA Astrophysics Data System (ADS)

    Stanley, James H.; Yancey, Robert N.

    1996-11-01

    The next century will witness at least two great revolutions in the way goods are produced. First, workers will use the medium of virtual reality in all aspects of marketing, research, development, prototyping, manufacturing, sales and service. Second, market forces will drive manufacturing towards small-lot production and just-in-time delivery. Already, we can discern the merging of these megatrends into what some are calling agile manufacturing. Under this new paradigm, parts and processes will be designed and engineered within the mind of a computer, tooled and manufactured by the offspring of today's rapid prototyping equipment, and evaluated for performance and reliability by advanced nondestructive evaluation (NDE) techniques and sophisticated computational models. Computed tomography (CT) is the premier example of an NDE method suitable for future agile manufacturing activities. It is the only modality that provides convenient access to the full suite of engineering data that users will need to avail themselves of computer- aided design, computer-aided manufacturing, and computer- aided engineering capabilities, as well as newly emerging reverse engineering, rapid prototyping and solid freeform fabrication technologies. As such, CT is assured a central, utilitarian role in future industrial operations. An overview of this exciting future for industrial CT is presented.

  20. Beam injection into RHIC

    SciTech Connect

    Fischer, W.; Hahn, H.; MacKay, W.W.; Satogata, T.; Tsoupas, N.; Zhang, W.

    1997-07-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. The authors describe the injection zone and its bottlenecks. They report on the commissioning of the injection system, on beam based measurements of the kickers and the application program to steer the beam.

  1. Continuous angle steering of an optically- controlled phased array antenna based on differential true time delay constituted by micro-optical components.

    PubMed

    Wang, Jian; Hou, Peipei; Cai, Haiwen; Sun, Jianfeng; Wang, Shunan; Wang, Lijuan; Yang, Fei

    2015-04-01

    We propose an optically controlled phased array antenna (PAA) based on differential true time delay constructed optical beamforming network (OBFN). Differential true time delay is realized by stack integrated micro-optical components. Optically-controlled angle steering of radio frequency (RF) beams are realized and demonstrated by this configuration. Experimental results demonstrate that OBFN based PAA can accomplish RF-independent broadband beam steering without beam squint effect and can achieve continuous angle steering. In addition, multi-beams for different steering angles are acquired synchronously. PMID:25968773

  2. Continuous angle steering of an optically- controlled phased array antenna based on differential true time delay constituted by micro-optical components.

    PubMed

    Wang, Jian; Hou, Peipei; Cai, Haiwen; Sun, Jianfeng; Wang, Shunan; Wang, Lijuan; Yang, Fei

    2015-04-01

    We propose an optically controlled phased array antenna (PAA) based on differential true time delay constructed optical beamforming network (OBFN). Differential true time delay is realized by stack integrated micro-optical components. Optically-controlled angle steering of radio frequency (RF) beams are realized and demonstrated by this configuration. Experimental results demonstrate that OBFN based PAA can accomplish RF-independent broadband beam steering without beam squint effect and can achieve continuous angle steering. In addition, multi-beams for different steering angles are acquired synchronously.

  3. Optimization of steering elements in the RIA driver linac.

    SciTech Connect

    Lessner, E. S.; Aseev, V. S.; Ostroumov, P. N.; Physics

    2005-01-01

    The driver linac of the projected RIA facility is a versatile accelerator, a 1.4-GV, CW superconducting (SC) linac designed to simultaneously accelerate several heavy-ion charge states, providing beams from proton to uranium at 400 MeV/u at power levels at a minimum of 100 kW and up to 400 kW for most beams. Acceleration of multiple-charge-state uranium beams places stringent requirements on the linac design. A steering algorithm was derived that fulfilled the driver's real estate requirements, such as placement of steering dipole coils on SC solenoids and of beam position monitors outside cryostats, and beam-dynamics requirements, such as coupling effects induced by the focusing solenoids. The algorithm has been fully integrated into the tracking code TRACK and it is used to study and optimize the number and position of steering elements that minimize the multiple-beam centroid oscillations and preserve the beam emittance under misalignments of accelerating and transverse focusing elements in the driver linac.

  4. Opening up the Agile Innovation Process

    NASA Astrophysics Data System (ADS)

    Conboy, Kieran; Donnellan, Brian; Morgan, Lorraine; Wang, Xiaofeng

    The objective of this panel is to discuss how firms can operate both an open and agile innovation process. In an era of unprecedented changes, companies need to be open and agile in order to adapt rapidly and maximize their innovation processes. Proponents of agile methods claim that one of the main distinctions between agile methods and their traditional bureaucratic counterparts is their drive toward creativity and innovation. However, agile methods are rarely adopted in their textbook, "vanilla" format, and are usually adopted in part or are tailored or modified to suit the organization. While we are aware that this happens, there is still limited understanding of what is actually happening in practice. Using innovation adoption theory, this panel will discuss the issues and challenges surrounding the successful adoption of agile practices. In addition, this panel will report on the obstacles and benefits reported by over 20 industrial partners engaged in a pan-European research project into agile practices between 2006 and 2009.

  5. Steering characteristics of motorcycles

    NASA Astrophysics Data System (ADS)

    Fujii, Shigeru; Shiozawa, Souichi; Shinagawa, Akinori; Kishi, Tomoaki

    2012-08-01

    In this study, the results of a steady-state cornering test using a sport-touring motorcycle and the analysis of those test results are presented. This test was conducted as an activity in our efforts to realise a quantitative development method for motorcycles. The measurement data from this test include measurement results for tyre force, tyre moment, and tyre slip angle that have not been practically addressed in the research of motorcycles, in addition to normal measurement results for velocity, steering angle, steering torque, roll angle, etc. Until now research on motorcycle dynamics characteristics has indicated that 'there is a strong relationship between the motorcycle dynamics characteristics and the tyre slip angle'. However, since it is difficult to take highly precise measurements of the motorcycle's tyre slip angle during actual riding, especially when the motorcycle is tilted during cornering, such measurements have been avoided, cf. [H. Ishii and Y. Tezuka, Considerations of turning performance for motorcycle, SETC (1997), pp. 383-389]. Nevertheless, in this research we attempted to measure the tyre slip angle and also attempted to investigate in detail the dynamics characteristics and tyre characteristics during riding. Until now there has not been an adequate investigation conducted under a variety of riding conditions, but it is the aim of this research to show that it is possible to measure the tyre slip angle with a reasonable accuracy. It is our opinion that this will open a new path to a more detailed investigation of the motorcycle's dynamics characteristics. In addition, we conducted measurements using not only the normal rider's lean angle (lean-with posture), but also measurements in the case where the rider's lean angle was intentionally changed, in order to investigate the effects that a change in the rider's posture has on the variation in the measurement results of the motorcycle's dynamics. Furthermore, we then compared these

  6. Social Protocols for Agile Virtual Teams

    NASA Astrophysics Data System (ADS)

    Picard, Willy

    Despite many works on collaborative networked organizations (CNOs), CSCW, groupware, workflow systems and social networks, computer support for virtual teams is still insufficient, especially support for agility, i.e. the capability of virtual team members to rapidly and cost efficiently adapt the way they interact to changes. In this paper, requirements for computer support for agile virtual teams are presented. Next, an extension of the concept of social protocol is proposed as a novel model supporting agile interactions within virtual teams. The extended concept of social protocol consists of an extended social network and a workflow model.

  7. Diesel Technology: Steering and Suspension.

    ERIC Educational Resources Information Center

    Miller, Roger; Scarberry, Terry; Tesch, Carl; Kellum, Mary

    Competency-based teacher and student materials on steering and suspension are provided for a diesel technology curriculum. Eleven units of instruction cover the following topics: chassis, tires, and wheels; steering; and suspension. The materials are based on the curriculum-alignment concept of first stating the objectives, then developing…

  8. Quantum coherence of steered states

    PubMed Central

    Hu, Xueyuan; Milne, Antony; Zhang, Boyang; Fan, Heng

    2016-01-01

    Lying at the heart of quantum mechanics, coherence has recently been studied as a key resource in quantum information theory. Quantum steering, a fundamental notion originally considered by Schödinger, has also recently received much attention. When Alice and Bob share a correlated quantum system, Alice can perform a local measurement to ‘steer’ Bob’s reduced state. We introduce the maximal steered coherence as a measure describing the extent to which steering can remotely create coherence; more precisely, we find the maximal coherence of Bob’s steered state in the eigenbasis of his original reduced state, where maximization is performed over all positive-operator valued measurements for Alice. We prove that maximal steered coherence vanishes for quantum-classical states whilst reaching a maximum for pure entangled states with full Schmidt rank. Although invariant under local unitary operations, maximal steered coherence may be increased when Bob performs a channel. For a two-qubit state we find that Bob’s channel can increase maximal steered coherence if and only if it is neither unital nor semi-classical, which coincides with the condition for increasing discord. Our results show that the power of steering for coherence generation, though related to discord, is distinct from existing measures of quantum correlation. PMID:26781214

  9. Enabling Agile Testing through Continuous Integration

    SciTech Connect

    Stolberg, Sean E.

    2009-08-24

    A Continuous Integration system is often considered one of the key elements involved in supporting an agile software development and testing environment. As a traditional software tester transitioning to an agile development environment it became clear to me that I would need to put this essential infrastructure in place and promote improved development practices in order to make the transition to agile testing possible. This experience report discusses a continuous integration implementation I lead last year. The initial motivations for implementing continuous integration are discussed and a pre and post-assessment using Martin Fowler's "Practices of Continuous Integration" is provided along with the technical specifics of the implementation. Finally, I’ll wrap up with a retrospective of my experiences implementing and promoting continuous integration within the context of agile testing.

  10. Participatory Design Activities and Agile Software Development

    NASA Astrophysics Data System (ADS)

    Kautz, Karlheinz

    This paper contributes to the studies of design activities in information systems development. It provides a case study of a large agile development project and focusses on how customers and users participated in agile development and design activities in practice. The investigated project utilized the agile method eXtreme Programming. Planning games, user stories and story cards, working software, and acceptance tests structured the customer and user involvement. We found genuine customer and user involvement in the design activities in the form of both direct and indirect participation in the agile development project. The involved customer representatives played informative, consultative, and participative roles in the project. This led to their functional empowerment— the users were enabled to carry out their work to their own satisfaction and in an effective, efficient, and economical manner.

  11. LUMINOSITY OPTIMIZATION USING AUTOMATED IR STEERING AT RHIC.

    SciTech Connect

    DREES,A.D'OTTAVIO,T.

    2004-07-05

    The goal of the RHIC 2004 Au-Au run was to maximize the achieved integrated luminosity. One way is to increase beam currents and minimize beam transverse emittances. Another important ingredient is the minimization of time spent on activities postponing the declaration of ''physics conditions'', i.e. stable beam conditions allowing the experimental detectors to take data. Since collision rates are particularly high in the beginning of the store the integrated luminosity benefits considerably from any minute saved early in the store. In the RHIC run 2004 a new IR steering application uses luminosity monitor signals as a feedback for a fully automated steering procedure. This report gives an overview of the used procedure and summarizes the achieved results.

  12. Steering Bell-diagonal states

    PubMed Central

    Quan, Quan; Zhu, Huangjun; Liu, Si-Yuan; Fei, Shao-Ming; Fan, Heng; Yang, Wen-Li

    2016-01-01

    We investigate the steerability of two-qubit Bell-diagonal states under projective measurements by the steering party. In the simplest nontrivial scenario of two projective measurements, we solve this problem completely by virtue of the connection between the steering problem and the joint-measurement problem. A necessary and sufficient criterion is derived together with a simple geometrical interpretation. Our study shows that a Bell-diagonal state is steerable by two projective measurements iff it violates the Clauser-Horne-Shimony-Holt (CHSH) inequality, in sharp contrast with the strict hierarchy expected between steering and Bell nonlocality. We also introduce a steering measure and clarify its connections with concurrence and the volume of the steering ellipsoid. In particular, we determine the maximal concurrence and ellipsoid volume of Bell-diagonal states that are not steerable by two projective measurements. Finally, we explore the steerability of Bell-diagonal states under three projective measurements. A simple sufficient criterion is derived, which can detect the steerability of many states that are not steerable by two projective measurements. Our study offers valuable insight on steering of Bell-diagonal states as well as the connections between entanglement, steering, and Bell nonlocality. PMID:26911250

  13. Experimental analysis of beam pointing system based on liquid crystal optical phase array

    NASA Astrophysics Data System (ADS)

    Shi, Yubin; Zhang, Jianmin; Zhang, Zhen

    2016-06-01

    In this paper, we propose and demonstrate an elementary non-mechanical beam aiming and steering system with a single liquid crystal optical phase array (LC-OPA) and charge-coupled device (CCD). With the conventional method of beam steering control, the LC-OPA device can realize one dimensional beam steering continuously. An improved beam steering strategy is applied to realize two dimensional beam steering with a single LC-OPA. The whole beam aiming and steering system, including an LC-OPA and a retroreflective target, is controlled by the monitor. We test the feasibility of beam steering strategy both in one dimension and in two dimension at first, then the whole system is build up based on the improved strategy. The experimental results show that the max experimental pointing error is 56 µrad, and the average pointing error of the system is 19 µrad.

  14. Software ``Best'' Practices: Agile Deconstructed

    NASA Astrophysics Data System (ADS)

    Fraser, Steven

    Software “best” practices depend entirely on context - in terms of the problem domain, the system constructed, the software designers, and the “customers” ultimately deriving value from the system. Agile practices no longer have the luxury of “choosing” small non-mission critical projects with co-located teams. Project stakeholders are selecting and adapting practices based on a combina tion of interest, need and staffing. For example, growing product portfolios through a merger or the acquisition of a company exposes legacy systems to new staff, new software integration challenges, and new ideas. Innovation in communications (tools and processes) to span the growth and contraction of both information and organizations, while managing the adoption of changing software practices, is imperative for success. Traditional web-based tools such as web pages, document libraries, and forums are not suf ficient. A blend of tweeting, blogs, wikis, instant messaging, web-based confer encing, and telepresence creates a new dimension of communication “best” practices.

  15. Levels of steering control: Reproduction of steering-wheel movements

    NASA Technical Reports Server (NTRS)

    Godthelp, H.

    1982-01-01

    A schematic description of the steering control process is presented. It is shown that this process can be described in terms of levels of control. Level of control will depend on driver's skill in making use of 'clever' strategies which may be related to knowledge about the path to follow (input) and/or the vehicle under control. This knowledge may be referred to as an internal model of a particular task element. Internal information, as derived from these internal models will probably be used together with proprioceptive feedback. It is hypothesized that the efficiency of the higher levels of control will be dependent on the accuracy of both the internal and proprioceptive information. Based on this research philosophy a series of experiments is carried out. Two primary experiments were done in order to analyse subjects' ability to reproduce steering-wheel positions and movements without visual feedback. Steering-wheel angle amplitude, steering force and movement frequency were involved as independent variables.

  16. Beam Injection into RHIC

    NASA Astrophysics Data System (ADS)

    Fischer, W.; Hahn, H.; Mackay, W. W.; Tsoupas, N.

    1997-05-01

    During the RHIC sextant test in January 1997 beam was injected into a sixth of one of the rings for the first time. We describe the injection zone and its bottlenecks, the application program to steer the beam and the injection kickers. We report on the commissioning of the injection systems and on measurements of the kickers.

  17. Gamma-ray Astrophysics with AGILE

    SciTech Connect

    Longo, Francesco |; Tavani, M.; Barbiellini, G.; Argan, A.; Basset, M.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P.; Chen, A.; Costa, E.; Del Monte, E.; Di Cocco, G.; Di Persio, G.; Donnarumma, I.; Feroci, M.; Fiorini, M.; Foggetta, L.; Froysland, T.; Frutti, M.

    2007-07-12

    AGILE will explore the gamma-ray Universe with a very innovative instrument combining for the first time a gamma-ray imager and a hard X-ray imager. AGILE will be operational in spring 2007 and it will provide crucial data for the study of Active Galactic Nuclei, Gamma-Ray Bursts, unidentified gamma-ray sources. Galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing. The AGILE instrument is designed to simultaneously detect and image photons in the 30 MeV - 50 GeV and 15 - 45 keV energy bands with excellent imaging and timing capabilities, and a large field of view covering {approx} 1/5 of the entire sky at energies above 30 MeV. A CsI calorimeter is capable of GRB triggering in the energy band 0.3-50 MeV AGILE is now (March 2007) undergoing launcher integration and testing. The PLSV launch is planned in spring 2007. AGILE is then foreseen to be fully operational during the summer of 2007.

  18. Fighter agility metrics. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Liefer, Randall K.

    1990-01-01

    Fighter flying qualities and combat capabilities are currently measured and compared in terms relating to vehicle energy, angular rates and sustained acceleration. Criteria based on these measurable quantities have evolved over the past several decades and are routinely used to design aircraft structures, aerodynamics, propulsion and control systems. While these criteria, or metrics, have the advantage of being well understood, easily verified and repeatable during test, they tend to measure the steady state capability of the aircraft and not its ability to transition quickly from one state to another. Proposed new metrics to assess fighter aircraft agility are collected and analyzed. A framework for classification of these new agility metrics is developed and applied. A complete set of transient agility metrics is evaluated with a high fidelity, nonlinear F-18 simulation. Test techniques and data reduction methods are proposed. A method of providing cuing information to the pilot during flight test is discussed. The sensitivity of longitudinal and lateral agility metrics to deviations from the pilot cues is studied in detail. The metrics are shown to be largely insensitive to reasonable deviations from the nominal test pilot commands. Instrumentation required to quantify agility via flight test is also considered. With one exception, each of the proposed new metrics may be measured with instrumentation currently available.

  19. Responder fast steering mirror

    NASA Astrophysics Data System (ADS)

    Bullard, Andrew; Shawki, Islam

    2013-10-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  20. Responder fast steering mirror

    NASA Astrophysics Data System (ADS)

    Bullard, Andrew; Shawki, Islam

    2013-09-01

    Raytheon Space and Airborne Systems (SAS) has designed, built and tested a 3.3-inch diameter fast steering mirror (FSM) for space application. This 2-axis FSM operates over a large angle (over 10 degree range), has a very high servo bandwidth (over 3.3 Khz closed loop bandwidth), has nanoradian-class noise, and is designed to support microradian class line of sight accuracy. The FSM maintains excellent performance over large temperature ranges (which includes wave front error) and has very high reliability with the help of fully redundant angle sensors and actuator circuits. The FSM is capable of achieving all its design requirements while also being reaction-compensated. The reaction compensation is achieved passively and does not need a separate control loop. The FSM has undergone various environmental testing which include exported forces and torques and thermal vacuum testing that support the FSM design claims. This paper presents the mechanical design and test results of the mechanism which satisfies the rigorous vacuum and space application requirements.

  1. Contribution of Agility to Successful Distributed Software Development

    NASA Astrophysics Data System (ADS)

    Sarker, Saonee; Munson, Charles L.; Sarker, Suprateek; Chakraborty, Suranjan

    In recent times, both researchers and practitioners have touted agility as the latest innovation in distributed software development (DSD). In spite of this acknowledgement, there is little understanding and evidence surrounding the effect of agility on distributed project success. This chapter reports on a study that examines practitioner views surrounding the relative importance of different sub-types of agility to DSD project success. Preliminary results indicate that practitioners view on-time completion of DSD projects, and effective collaboration amongst stakeholders as the top two criteria of DSD project success, with lower emphasis on within-budget considerations. Among the many agility sub-types examined, people-based agility, communication-based agility, methodological agility, and time-based agility emerged as the most important for practitioners in terms of ensuring DSD project success.

  2. An investigation of fighter aircraft agility

    NASA Technical Reports Server (NTRS)

    Valasek, John; Downing, David R.

    1993-01-01

    This report attempts to unify in a single document the results of a series of studies on fighter aircraft agility funded by the NASA Ames Research Center, Dryden Flight Research Facility and conducted at the University of Kansas Flight Research Laboratory during the period January 1989 through December 1993. New metrics proposed by pilots and the research community to assess fighter aircraft agility are collected and analyzed. The report develops a framework for understanding the context into which the various proposed fighter agility metrics fit in terms of application and testing. Since new metrics continue to be proposed, this report does not claim to contain every proposed fighter agility metric. Flight test procedures, test constraints, and related criteria are developed. Instrumentation required to quantify agility via flight test is considered, as is the sensitivity of the candidate metrics to deviations from nominal pilot command inputs, which is studied in detail. Instead of supplying specific, detailed conclusions about the relevance or utility of one candidate metric versus another, the authors have attempted to provide sufficient data and analyses for readers to formulate their own conclusions. Readers are therefore ultimately responsible for judging exactly which metrics are 'best' for their particular needs. Additionally, it is not the intent of the authors to suggest combat tactics or other actual operational uses of the results and data in this report. This has been left up to the user community. Twenty of the candidate agility metrics were selected for evaluation with high fidelity, nonlinear, non real-time flight simulation computer programs of the F-5A Freedom Fighter, F-16A Fighting Falcon, F-18A Hornet, and X-29A. The information and data presented on the 20 candidate metrics which were evaluated will assist interested readers in conducting their own extensive investigations. The report provides a definition and analysis of each metric; details

  3. SuperAGILE and Gamma Ray Bursts

    SciTech Connect

    Pacciani, Luigi; Costa, Enrico; Del Monte, Ettore; Donnarumma, Immacolata; Evangelista, Yuri; Feroci, Marco; Frutti, Massimo; Lazzarotto, Francesco; Lapshov, Igor; Rubini, Alda; Soffitta, Paolo; Tavani, Marco; Barbiellini, Guido; Mastropietro, Marcello; Morelli, Ennio; Rapisarda, Massimo

    2006-05-19

    The solid-state hard X-ray imager of AGILE gamma-ray mission -- SuperAGILE -- has a six arcmin on-axis angular resolution in the 15-45 keV range, a field of view in excess of 1 steradian. The instrument is very light: 5 kg only. It is equipped with an on-board self triggering logic, image deconvolution, and it is able to transmit the coordinates of a GRB to the ground in real-time through the ORBCOMM constellation of satellites. Photon by photon Scientific Data are sent to the Malindi ground station at every contact. In this paper we review the performance of the SuperAGILE experiment (scheduled for a launch in the middle of 2006), after its first onground calibrations, and show the perspectives for Gamma Ray Bursts.

  4. Explaining the Obvious - How Do You Teach Agile?

    NASA Astrophysics Data System (ADS)

    Lundh, Erik

    Agile is now a hot topic and many organizations decide on adopting “agile” without really knowing how and why. This workshop will explore how fresh and seasoned agile coaches teach traditional and novel agile concepts, by example, with discussions. All participants are invited to show and tell about agile with an audience of peers. It might be the fresh first time with an audience, or golden hits that served you well for years.

  5. Agile interferometry: a non-traditional approach

    NASA Astrophysics Data System (ADS)

    Riza, Nabeel A.; Yaqoob, Zahid

    2004-11-01

    A new approach called agile interferometry is introduced to attain interferometric information with high sensitivity and scenario-based intelligence. Compared to traditional interferometric techniques, the proposed method thrives on dynamic control of the reference signal strength and detector integration time for efficient interferometric detection with high signal-to-noise ratio and significantly improved detected signal dynamic range capabilities. Theoretical analysis is presented with the operational methodology of the new approach. A high-speed optical attenuator is required in the interferometer reference arm to implement the proposed agile interferometer.

  6. Control design for future agile fighters

    NASA Technical Reports Server (NTRS)

    Murphy, Patrick C.; Davidson, John B.

    1991-01-01

    The CRAFT control design methodology is presented. CRAFT stands for the design objectives addressed, namely, Control power, Robustness, Agility, and Flying Qualities Tradeoffs. The approach combines eigenspace assignment, which allows for direct specification of eigenvalues and eigenvectors, and a graphical approach for representing control design metrics that captures numerous design goals in one composite illustration. The methodology makes use of control design metrics from four design objective areas, namely, control power, robustness, agility, and flying qualities. An example of the CRAFT methodology as well as associated design issues are presented.

  7. Quantitative measurement of CyberKnife robotic arm steering.

    PubMed

    Wong, K H; Dieterich, S; Tang, J; Cleary, K

    2007-12-01

    Respiratory motion is a significant and challenging problem for radiation medicine. Without adequate compensation for respiratory motion, it is impossible to deliver highly conformal doses to tumors in the thorax and abdomen. The CyberKnife frameless stereotactic radiosurgery system with Synchrony provides respiratory motion adaptation by monitoring skin motion and dynamically steering the beam to follow the moving tumor. This study quantitatively evaluated this beam steering technology using optical tracking of both the linear accelerator and a ball-cube target. Respiratory motion of the target was simulated using a robotic motion platform and movement patterns recorded from previous CyberKnife patients. Our results show that Synchrony respiratory tracking can achieve sub-millimeter precision when following a moving object. PMID:17994788

  8. Comparison of steering angle and bandwidth for various phased array antenna concepts

    NASA Astrophysics Data System (ADS)

    Bonjour, Romain; Singleton, Matthew; Leuchtmann, Pascal; Leuthold, Juerg

    2016-08-01

    In this paper we compare different integratable ultra-fast tunable true-time delay concepts with respect to their performances in a phased array system. The performances of the schemes are assessed with respect to the supported range, i.e. the range within which beam steering for a given fractional bandwidth can be achieved with a gain flatness better than 3 dB. We also compare the array gain as of function of steering angle and fractional bandwidth.

  9. Beam shaping for CARS measurements in turbulent environments.

    PubMed

    Magnotti, Gaetano; Cutler, Andrew D; Danehy, Paul M

    2012-07-10

    This paper describes a new technique to mitigate the effect of beam steering on CARS measurements in turbulent, variable density environments. The new approach combines planar BOXCARS phase-matching with elliptical shaping of one of the beams to generate a signal robust to beam steering, while keeping the same spatial resolution. Numerical and experimental results are provided to demonstrate the effectiveness of this approach. One experiment investigates the effect of beam shaping in the presence of a controlled and well quantified displacement of the beams at the focal plane. Another experiment, more qualitative, proves the effectiveness of the technique in the presence of severe beam steering due to turbulence. PMID:22781249

  10. Coherent optical monolithic phased-array antenna steering system

    DOEpatents

    Hietala, Vincent M.; Kravitz, Stanley H.; Vawter, Gregory A.

    1994-01-01

    An optical-based RF beam steering system for phased-array antennas comprising a photonic integrated circuit (PIC). The system is based on optical heterodyning employed to produce microwave phase shifting by a monolithic PIC constructed entirely of passive components. Microwave power and control signal distribution to the antenna is accomplished by optical fiber, permitting physical separation of the PIC and its control functions from the antenna. The system reduces size, weight, complexity, and cost of phased-array antenna systems.

  11. Fast steering mirror for laser communication

    NASA Astrophysics Data System (ADS)

    Langenbach, Harald; Schmid, Manfred

    2005-07-01

    Future multimedia satellites require communication at large bandwidth which can be achieved by means of optical communication links. TESAT Spacecom is currently developing a Laser Communication Terminal (LCT) for such applications under DLR contract. EADS Astrium is developing and building the mechanisms for Pointing, Acquisition and Tracking (PAT) of the laser beam between two Laser Communication Terminals. Based on this development work the development of mechanism H/W to be flown on TerraSar X is currently under way. After a short description of the general arrangement of the Mechanisms inside the LCT, the paper describes the design of the fast steering mirrors (FSM) reflecting the critical requirements and the solutions how to achieve them.

  12. Adaptive null steering by reflector antennas

    NASA Astrophysics Data System (ADS)

    Cofer, J. W.; Martin, G. P.; Ralph, S. E.

    The feasibility of peforming adaptive null steering by reflector antennas is investigated, and the results are reported. The implementation consists of an array of feed elements located in the focal region. The outputs of all the feeds are weighted in phase and amplitude and summed coherently. After deduction by a receiver, the signal passes to a digital algorithm computer where a decision is made as to how the weights should be adjusted, and interactive perturbational process continues until the system has arrived at an optimal weight combination. The configuration allows for multiple jammers and/or desired signals. Nulls on the order of 35 dB can be achieved with the basic limitation being amplitude and phase balance of the RF weights versus frequency. The system offers simpler, lighter weight more economically than full-phased arrays, much broader bandwidth than sidelobe cancellers, well-understood analysis procedures, and allows cancellation high up on the main beam.

  13. 49 CFR 393.209 - Steering wheel systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... rotation for manual steering systems, and 30 degrees angular rotation for power steering systems. (c... arm on the steering gear output shaft shall not be loose. Steering wheels shall turn freely...

  14. 5th Annual AGILE Science Workshop

    NASA Technical Reports Server (NTRS)

    Hunter, Stanley

    2008-01-01

    The EGRET model of the galactic diffuse gamma-ray emission (GALDIF) has been extended to provide full-sky coverage and improved to address the discrepancies with the EGRET data. This improved model is compared with the AGILE results from the Galactic center. The comparison is discussed.

  15. Lean and Agile: An Epistemological Reflection

    ERIC Educational Resources Information Center

    Browaeys, Marie-Joelle; Fisser, Sandra

    2012-01-01

    Purpose: The aim of the paper is to contribute to the discussion of treating the concepts of lean and agile in isolation or combination by presenting an alternative view from complexity thinking on these concepts, considering an epistemological approach to this topic. Design/methodology/approach: The paper adopts an epistemological approach, using…

  16. Achieving agility through parameter space qualification

    SciTech Connect

    Diegert, K.V.; Easterling, R.G.; Ashby, M.R.; Benavides, G.L.; Forsythe, C.; Jones, R.E.; Longcope, D.B.; Parratt, S.W.

    1995-02-01

    The A-primed (Agile Product Realization of Innovative electro-Mechanical Devices) project is defining and proving processes for agile product realization for the Department of Energy complex. Like other agile production efforts reported in the literature, A-primed uses concurrent engineering and information automation technologies to enhance information transfer. A unique aspect of our approach to agility is the qualification during development of a family of related product designs and their production processes, rather than a single design and its attendant processes. Applying engineering principles and statistical design of experiments, economies of test and analytic effort are realized for the qualification of the device family as a whole. Thus the need is minimized for test and analysis to qualify future devices from this family, thereby further reducing the design-to-production cycle time. As a measure of the success of the A-primed approach, the first design took 24 days to produce, and operated correctly on the first attempt. A flow diagram for the qualification process is presented. Guidelines are given for implementation, based on the authors experiences as members of the A-primed qualification team.

  17. Comparison of a New Test For Agility and Skill in Soccer With Other Agility Tests

    PubMed Central

    Kutlu, Mehmet; Yapıcı, Hakan; Yoncalık, Oğuzhan; Çelik, Serkan

    2012-01-01

    The purpose of this study was both to develop a novel test to measure run, shuttle run and directional change agility, and soccer shots on goal with decision making and to compare it with other agility tests. Multiple comparisons and assessments were conducted, including test-retest, Illinois, Zig-Zag, 30 m, Bosco, T-drill agility, and Wingate peak power tests. A total of 113 Turkish amateur and professional soccer players and tertiary-level students participated in the study. Test-retest and inter-tester reliability testing measures were conducted with athletes. The correlation coefficient of the new test was .88, with no significant difference (p> 0.01> 0.01) between the test results obtained in the first and second test sessions. The results of an analysis of variance revealed a significant (p < 0.01) difference between the T-drill agility and power test results for soccer players. The new agility and skill test is an acceptable and reliable test when considering test-retest reliability and inter-rater reliability. The findings in this study suggest that the novel soccer-specific agility and shooting test can be utilized in the testing and identification of soccer players’ talents. PMID:23486732

  18. AGILE and Gamma-Ray Bursts

    SciTech Connect

    Longo, Francesco; Tavani, M.; Barbiellini, G.; Argan, A.; Basset, M.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P.; Chen, A.; Costa, E.; Del Monte, E.; Di Cocco, G.; Di Persio, G.; Donnarumma, I.; Feroci, M.; Fiorini, M.; Foggetta, L.; Froysland, T.; Frutti, M.

    2006-05-19

    AGILE is a Scientific Mission dedicated to high-energy astrophysics supported by ASI with scientific participation of INAF and INFN. The AGILE instrument is designed to simultaneously detect and image photons in the 30 MeV - 50 GeV and 15 - 45 keV energy bands with excellent imaging and timing capabilities, and a large field of view covering {approx} 1/5 of the entire sky at energies above 30 MeV. A CsI calorimeter is capable of GRB triggering in the energy band 0.3-50 MeV. The broadband detection of GRBs and the study of implications for particle acceleration and high energy emission are primary goals of th emission. AGILE can image GRBs with 2-3 arcminutes error boxes in the hard X-ray range, and provide broadband photon-by photon detection in the 15-45 keV, 03-50 MeV, and 30 MeV-30 GeV energy ranges. Microsecond on-board photon tagging and a {approx} 100 microsecond gamma-ray detection deadtime will be crucial for fast GRB timing. On-board calculated GRB coordinates and energy fluxes will be quickly transmitted to the ground by an ORBCOMM transceiver. AGILE have recently (December 2005) completed its gamma-ray calibration. It is now (January 2006) undergoing satellite integration and testing. The PLSV launch is planned in early 2006. AGILE is then foreseen to be fully operational during the summer of 2006. It will be the only mission entirely dedicated to high-energy astrophysics above 30 MeV during the period mid-2006/mid-2007.

  19. Driver steering model for closed-loop steering function analysis

    NASA Astrophysics Data System (ADS)

    Bolia, Pratiksh; Weiskircher, Thomas; Müller, Steffen

    2014-05-01

    In this paper, a two level preview driver steering control model for the use in numerical vehicle dynamics simulation is introduced. The proposed model is composed of cascaded control loops: The outer loop is the path following layer based on potential field framework. The inner loop tries to capture the driver's physical behaviour. The proposed driver model allows easy implementation of different driving situations to simulate a wide range of different driver types, moods and vehicle types. The expediency of the proposed driver model is shown with the help of developed driver steering assist (DSA) function integrated with a conventional series production (Electric Power steering System with rack assist servo unit) system. With the help of the DSA assist function, the driver is prevented from over saturating the front tyre forces and loss of stability and controllability during cornering. The simulation results show different driver reactions caused by the change in the parameters or properties of the proposed driver model if the DSA assist function is activated. Thus, the proposed driver model is useful for the advanced driver steering and vehicle stability assist function evaluation in the early stage of vehicle dynamics handling and stability evaluation.

  20. 33 CFR 401.18 - Steering lights.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Steering lights. 401.18 Section... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.18 Steering lights. Every vessel shall be equipped with: (a) A steering light located on the centerline at or near the stem of...

  1. 33 CFR 401.18 - Steering lights.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 3 2011-07-01 2011-07-01 false Steering lights. 401.18 Section... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.18 Steering lights. Every vessel shall be equipped with: (a) A steering light located on the centerline at or near the stem of...

  2. 46 CFR 169.251 - Steering apparatus.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Steering apparatus. 169.251 Section 169.251 Shipping... Inspection and Certification Inspections § 169.251 Steering apparatus. At each inspection for certification and periodic inspection the steering apparatus is inspected and operationally tested to determine...

  3. 46 CFR 169.251 - Steering apparatus.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Steering apparatus. 169.251 Section 169.251 Shipping... Inspection and Certification Inspections § 169.251 Steering apparatus. At each inspection for certification and periodic inspection the steering apparatus is inspected and operationally tested to determine...

  4. Remote manipulator system steering capability for SVDS

    NASA Technical Reports Server (NTRS)

    Martin, D. T.

    1977-01-01

    Details of the remote manipulator system steering capability to be implemented into the space vehicle dynamics simulator are reported. The resolve rate law is included as part of the overall steering capability. The steering model includes three automatic modes, four manual augmented modes, and a single joint rate mode.

  5. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... steering axle wheels in the straight ahead position, turn the steering wheel in one direction until there is a perceptible movement of the wheel. If a point on the steering wheel rim moves more than the value shown in Table 1 before perceptible return movement of the wheel under observation, there...

  6. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... steering axle wheels in the straight ahead position, turn the steering wheel in one direction until there is a perceptible movement of the wheel. If a point on the steering wheel rim moves more than the value shown in Table 1 before perceptible return movement of the wheel under observation, there...

  7. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... steering axle wheels in the straight ahead position, turn the steering wheel in one direction until there is a perceptible movement of the wheel. If a point on the steering wheel rim moves more than the value shown in Table 1 before perceptible return movement of the wheel under observation, there...

  8. 33 CFR 401.18 - Steering lights.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Steering lights. 401.18 Section... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.18 Steering lights. Every vessel shall be equipped with: (a) A steering light located on the centerline at or near the stem of...

  9. 33 CFR 401.18 - Steering lights.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 3 2012-07-01 2012-07-01 false Steering lights. 401.18 Section... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.18 Steering lights. Every vessel shall be equipped with: (a) A steering light located on the centerline at or near the stem of...

  10. 33 CFR 401.18 - Steering lights.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 3 2013-07-01 2013-07-01 false Steering lights. 401.18 Section... TRANSPORTATION SEAWAY REGULATIONS AND RULES Regulations Condition of Vessels § 401.18 Steering lights. Every vessel shall be equipped with: (a) A steering light located on the centerline at or near the stem of...

  11. Steering magnet design for a limited space

    SciTech Connect

    Okamura,M.; Fite, J.; Lodestro, V.; Raparia, D.; Ritter, J.

    2009-05-04

    We compare two extreme designs of steering magnets. The first one is a very thin steering magnet design which occupies only 6 mm in length and can be additionally installed as needed. The other is realized by applying extra coil windings to a quadrupole magnet and does not consume any length. The properties and the features of these steering magnets are discussed.

  12. Beam director design report

    SciTech Connect

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and prototype vernier steering magnet were designed and built. In volume II, copies are included of the funding instruments, requests for quotations, purchase orders, a complete set of as-built drawings, magnetic measurement reports, the concept design report, and the final report on the design and fabrication project. (LEW)

  13. The Physics Performance Of The Front Steering Launcher For The ITER ECRH Upper Port

    SciTech Connect

    Henderson, M.; Chavan, R.; Nikkola, P.; Sanchez, F.; Sauter, O.; Shidara, H.; Ramponi, G.; Saibene, G.; Zohm, H.

    2005-09-26

    The capability of any given e.m.-wave plasma heating system to be utilized for physics applications depends strongly on the technical properties of the launching antenna (or launcher). An effective ECH launcher must project a small mm-wave beam spot size far into the plasma and 'steer' the beam across a large fraction of the plasma cross section (along the resonance surface). Thus the choice in the launcher concept and design may either severely limit or enhance the capability of a heating system to be effectively applied for physics applications, such as sawtooth stabilization, control of the Neoclassical Tearing Mode (NTM), Edge Localized Mode (ELM) control, etc. Presently, two antenna concepts are under consideration for the ITER upper port ECH launcher: front steering (FS) and remote steering (RS) launchers. The RS launcher has the technical advantage of easier maintenance access to the steering mirror, which is isolated from the torus vacuum. The FS launcher places the steering mirror near the plasma increasing the technical challenges, but significantly enhancing the focusing and steering capabilities of the launcher, offering a threefold increase in NTM stabilization efficiency over the RS launcher as well as the potential for application to other critical physics issues such as ELM or sawtooth control.

  14. Frequency/phase agile microwave circuits on ferroelectric films

    NASA Astrophysics Data System (ADS)

    Romanofsky, Robert Raymond

    This work describes novel microwave circuits that can be tuned in either frequency or phase through the use of nonlinear dielectrics, specifically thin ferroelectric films. These frequency and phase agile circuits in many cases provide a new capability or offer the potential for lower cost alternatives in satellite and terrestrial communications and sensor applications. A brief introduction to nonlinear dielectrics and a summary of some of the special challenges confronting the practical insertion of ferroelectric technology into commercial systems is provided. A theoretical solution for the propagation characteristics of the multi-layer structures, with emphasis on a new type of phase shifter based on coupled microstrip, lines, is developed. The quasi-TEM analysis is based on a variational solution for line capacitance and an extension of coupled transmission line theory. It is shown that the theoretical model is applicable to a broad class of multi-layer transmission lines. The critical role that ferroelectric film thickness plays in loss and phase-shift is closely examined. Experimental data for both thin film BaxSr1-xTiO 3 phase shifters near room temperature and SMO3 phase shifters at cryogenic temperatures on MgO and LaAlO3 substrates is included. Some of these devices demonstrated an insertion loss of less than 5 dB at Ku-band with continuously variable phase shift in excess of 360 degrees. The performance of these devices is superior to the state-of-the-art semiconductor counterparts. Frequency and phase agile antenna prototypes including a microstrip patch that can operate at multiple microwave frequency bands and a new type of phased array antenna concept called the ferroelectric reflectarray are introduced. Modeled data for tunable microstrip patch antennas is presented for various ferroelectric film thickness. A prototype linear phased array, with a conventional beam-forming manifold, and an electronic controller is described. This is the first

  15. Dynamic tumor tracking using the Elekta Agility MLC

    SciTech Connect

    Fast, Martin F. Nill, Simeon Bedford, James L.; Oelfke, Uwe

    2014-11-01

    Purpose: To evaluate the performance of the Elekta Agility multileaf collimator (MLC) for dynamic real-time tumor tracking. Methods: The authors have developed a new control software which interfaces to the Agility MLC to dynamically program the movement of individual leaves, the dynamic leaf guides (DLGs), and the Y collimators (“jaws”) based on the actual target trajectory. A motion platform was used to perform dynamic tracking experiments with sinusoidal trajectories. The actual target positions reported by the motion platform at 20, 30, or 40 Hz were used as shift vectors for the MLC in beams-eye-view. The system latency of the MLC (i.e., the average latency comprising target device reporting latencies and MLC adjustment latency) and the geometric tracking accuracy were extracted from a sequence of MV portal images acquired during irradiation for the following treatment scenarios: leaf-only motion, jaw + leaf motion, and DLG + leaf motion. Results: The portal imager measurements indicated a clear dependence of the system latency on the target position reporting frequency. Deducting the effect of the target frequency, the leaf adjustment latency was measured to be 38 ± 3 ms for a maximum target speed v of 13 mm/s. The jaw + leaf adjustment latency was 53 ± 3 at a similar speed. The system latency at a target position frequency of 30 Hz was in the range of 56–61 ms for the leaves (v ≤ 31 mm/s), 71–78 ms for the jaw + leaf motion (v ≤ 25 mm/s), and 58–72 ms for the DLG + leaf motion (v ≤ 59 mm/s). The tracking accuracy showed a similar dependency on the target position frequency and the maximum target speed. For the leaves, the root-mean-squared error (RMSE) was between 0.6–1.5 mm depending on the maximum target speed. For the jaw + leaf (DLG + leaf) motion, the RMSE was between 0.7–1.5 mm (1.9–3.4 mm). Conclusions: The authors have measured the latency and geometric accuracy of the Agility MLC, facilitating its future use for clinical

  16. Null-steering techniques for application to large array antennas

    NASA Astrophysics Data System (ADS)

    Hockham, G. A.; Cho, C.; Parr, J. C.; Wolfson, R. I.

    A multimode waveguide can be employed to design an antenna which produces a beam for each propagating mode. A dual-beam waveguide slot array is particularly attractive. The antenna is compact, highly efficient, and has lower sidelobe-level performance than can be achieved with conventional monopulse techniques. Adaptive phase steering for jammer nulling is considered, taking into account a large phased array using a series feed system. The considered configuration was selected for computer simulation. A description is presented of a multiple beam antenna with independent steerable nulls. The multiple beam low-sidelobe antenna configuration has the ability to provide a radiation pattern with multiple and independently-located nulls, with minimal effect on the sidelobes of the unperturbed pattern.

  17. Objective evaluation method of steering comfort based on movement quality evaluation of driver steering maneuver

    NASA Astrophysics Data System (ADS)

    Yang, Yiyong; Liu, Yahui; Wang, Man; Ji, Run; Ji, Xuewu

    2014-09-01

    The existing research of steering comfort mainly focuses on the subjective evaluation, aiming at designing and optimizing the steering system. In the development of steering system, especially the evaluation of steering comfort, the objective evaluation methods considered the kinematic characteristics of driver steering maneuver are not proposed, which means that the objective evaluation of steering cannot be conducted with the evaluation of kinematic characteristics of driver in steering maneuver. In order to propose the objective evaluation methods of steering comfort, the evaluation of steering movement quality of driver is developed on the basis of the study of the kinematic characteristics of steering maneuver. First, the steering motion trajectories of the driver in both comfortable and certain extreme uncomfortable operation conditions are detected using the Vicon motion capture system. The operation conditions are under the restrictions of the vertical height and horizontal distance between steering wheel center and the H-point of driver, and the steering resisting torque else. Next, the movement quality evaluation of driver steering maneuver is assessed using twelve kinds of evaluation indices based on the kinematic analyses of the steering motion trajectories to propose an objective evaluation method. Finally, an integrated discomfort index of steering maneuver is proposed on the basis of the regression analysis of subjective evaluation rating and the movement quality evaluation indices, including the Jerk, Discomfort and Joint Torque indices. The test results show that the proposed integrated discomfort index gives a good fitting with the subjective evaluation of discomfort, which means it can be used to evaluate or predict the discomfort level of steering maneuver. This paper proposes an objective evaluation method of steering comfort based on the movement quality evaluation of driver steering maneuver.

  18. Compact, Automated, Frequency-Agile Microspectrofluorimeter

    NASA Technical Reports Server (NTRS)

    Fernandez, Salvador M.; Guignon, Ernest F.

    1995-01-01

    Compact, reliable, rugged, automated cell-culture and frequency-agile microspectrofluorimetric apparatus developed to perform experiments involving photometric imaging observations of single live cells. In original application, apparatus operates mostly unattended aboard spacecraft; potential terrestrial applications include automated or semiautomated diagnosis of pathological tissues in clinical laboratories, biomedical instrumentation, monitoring of biological process streams, and portable instrumentation for testing biological conditions in various environments. Offers obvious advantages over present laboratory instrumentation.

  19. Architecture-Centric Methods and Agile Approaches

    NASA Astrophysics Data System (ADS)

    Babar, Muhammad Ali; Abrahamsson, Pekka

    Agile software development approaches have had significant impact on industrial software development practices. Despite becoming widely popular, there is an increasing perplexity about the role and importance of a system’s software architecture in agile approaches [1, 2]. Advocates of the vital role of architecture in achieving quality goals of large-scale-software-intensive-systems are skeptics of the scalability of any development approach that does not pay sufficient attention to architectural issues. However, the proponents of agile approaches usually perceive the upfront design and evaluation of architecture as being of less value to the customers of a system. According to them, for example, re-factoring can help fix most of the problems. Many experiences show that large-scale re-factoring often results in significant defects, which are very costly to address later in the development cycle. It is considered that re-factoring is worthwhile as long as the high-level design is good enough to limit the need for large-scale re-factoring [1, 3, 4].

  20. First GRB detections with the AGILE Minicalorimeter

    NASA Astrophysics Data System (ADS)

    Marisaldi, M.; Labanti, C.; Fuschino, F.; Galli, M.; Tavani, M.; Bulgarelli, A.; Gianotti, F.; Trifoglio, M.; Argan, A.

    2008-05-01

    The Minicalorimeter (MCAL) onboard the AGILE satellite is a 1400 cm2 scintillation detector sensitive in the energy range 0.3-200 MeV. MCAL works both as a slave of the AGILE Silicon Tracker and as an autonomous detector for transient events (BURST mode). A dedicated onboard Burst Search logic scans BURST mode data in search of count rate increase. Peculiar characteristics of the detector are the high energy spectral coverage and a timing resolution of about 2 microseconds. Even if a trigger is not issued, BURST mode data are used to build a broad band energy spectrum (scientific ratemeters) organized in 11 bands for each of the two MCAL detection planes, with a time resolution of 1 second. After the first engineering commissioning phase, following the AGILE launch on 23rd April 2007, between 22nd June and 5th November 2007 eighteen GRBs were detected offline in the scientific ratemeters data, with a detection rate of about one per week. In this paper the capabilities of the detector will be described and an overview of the first detected GRBs will be given.

  1. First GRB detections with the AGILE Minicalorimeter

    SciTech Connect

    Marisaldi, M.; Labanti, C.; Fuschino, F.; Bulgarelli, A.; Gianotti, F.; Trifoglio, M.; Galli, M.; Tavani, M.; Argan, A.

    2008-05-22

    The Minicalorimeter (MCAL) onboard the AGILE satellite is a 1400 cm{sup 2} scintillation detector sensitive in the energy range 0.3-200 MeV. MCAL works both as a slave of the AGILE Silicon Tracker and as an autonomous detector for transient events (BURST mode). A dedicated onboard Burst Search logic scans BURST mode data in search of count rate increase. Peculiar characteristics of the detector are the high energy spectral coverage and a timing resolution of about 2 microseconds. Even if a trigger is not issued, BURST mode data are used to build a broad band energy spectrum (scientific ratemeters) organized in 11 bands for each of the two MCAL detection planes, with a time resolution of 1 second. After the first engineering commissioning phase, following the AGILE launch on 23rd April 2007, between 22nd June and 5th November 2007 eighteen GRBs were detected offline in the scientific ratemeters data, with a detection rate of about one per week. In this paper the capabilities of the detector will be described and an overview of the first detected GRBs will be given.

  2. Agile manufacturing: The factory of the future

    NASA Technical Reports Server (NTRS)

    Loibl, Joseph M.; Bossieux, Terry A.

    1994-01-01

    The factory of the future will require an operating methodology which effectively utilizes all of the elements of product design, manufacturing and delivery. The process must respond rapidly to changes in product demand, product mix, design changes or changes in the raw materials. To achieve agility in a manufacturing operation, the design and development of the manufacturing processes must focus on customer satisfaction. Achieving greatest results requires that the manufacturing process be considered from product concept through sales. This provides the best opportunity to build a quality product for the customer at a reasonable rate. The primary elements of a manufacturing system include people, equipment, materials, methods and the environment. The most significant and most agile element in any process is the human resource. Only with a highly trained, knowledgeable work force can the proper methods be applied to efficiently process materials with machinery which is predictable, reliable and flexible. This paper discusses the affect of each element on the development of agile manufacturing systems.

  3. Future Research in Agile Systems Development: Applying Open Innovation Principles Within the Agile Organisation

    NASA Astrophysics Data System (ADS)

    Conboy, Kieran; Morgan, Lorraine

    A particular strength of agile approaches is that they move away from ‘introverted' development and intimately involve the customer in all areas of development, supposedly leading to the development of a more innovative and hence more valuable information system. However, we argue that a single customer representative is too narrow a focus to adopt and that involvement of stakeholders beyond the software development itself is still often quite weak and in some cases non-existent. In response, we argue that current thinking regarding innovation in agile development needs to be extended to include multiple stakeholders outside the business unit. This paper explores the intra-organisational applicability and implications of open innovation in agile systems development. Additionally, it argues for a different perspective of project management that includes collaboration and knowledge-sharing with other business units, customers, partners, and other relevant stakeholders pertinent to the business success of an organisation, thus embracing open innovation principles.

  4. All-optical steering of the interactions between multiple spatial solitons in isotropic polymers

    NASA Astrophysics Data System (ADS)

    Yan, Li-fen; Zhang, Dong; Jin, Qing-li; Wang, Hong-cheng; Zhang, Yao-ju

    2010-11-01

    All-optical steering of the nonlinear interactions between multiple spatial solitons can be performed in an isotropic photoisomerization polymer, by propagating an external control beam in perpendicular direction. Fusing, giving birth to another new soliton, and transferring energy can take place in the interactions of signal beams, which can be achieved by changing the incident position of the control beam, the initial relative phase and the power ratio between the signal beams and the control beam. These phenomena are physically explained, and they have significantly potential applications in optical signal readdressing, logic gating, and all-optical switching, etc.

  5. Extracting quantum coherence via steering

    PubMed Central

    Hu, Xueyuan; Fan, Heng

    2016-01-01

    As the precious resource for quantum information processing, quantum coherence can be created remotely if the involved two sites are quantum correlated. It can be expected that the amount of coherence created should depend on the quantity of the shared quantum correlation, which is also a resource. Here, we establish an operational connection between coherence induced by steering and the quantum correlation. We find that the steering-induced coherence quantified by such as relative entropy of coherence and trace-norm of coherence is bounded from above by a known quantum correlation measure defined as the one-side measurement-induced disturbance. The condition that the upper bound saturated by the induced coherence varies for different measures of coherence. The tripartite scenario is also studied and similar conclusion can be obtained. Our results provide the operational connections between local and non-local resources in quantum information processing. PMID:27682450

  6. Applying Agile MethodstoWeapon/Weapon-Related Software

    SciTech Connect

    Adams, D; Armendariz, M; Blackledge, M; Campbell, F; Cloninger, M; Cox, L; Davis, J; Elliott, M; Granger, K; Hans, S; Kuhn, C; Lackner, M; Loo, P; Matthews, S; Morrell, K; Owens, C; Peercy, D; Pope, G; Quirk, R; Schilling, D; Stewart, A; Tran, A; Ward, R; Williamson, M

    2007-05-02

    This white paper provides information and guidance to the Department of Energy (DOE) sites on Agile software development methods and the impact of their application on weapon/weapon-related software development. The purpose of this white paper is to provide an overview of Agile methods, examine the accepted interpretations/uses/practices of these methodologies, and discuss the applicability of Agile methods with respect to Nuclear Weapons Complex (NWC) Technical Business Practices (TBPs). It also provides recommendations on the application of Agile methods to the development of weapon/weapon-related software.

  7. Bulk acousto-optic wavelength agile filter module for a wavelength-multiplexed optical scanner.

    PubMed

    Yaqoob, Zahid; Riza, Nabeel A

    2005-05-01

    An acousto-optic tunable filter-based wavelength-selection module with features optimized for a wavelength-multiplexed optical scanner (W-MOS) is proposed and demonstrated. The W-MOS produces high-speed multiple scan beams if it is engaged with an agile tunable source with multiwavelength generation capability. In particular, the proposed fiber-connected module features high-speed, low-loss, narrow-linewidth, and single-multiple wavelength selection by means of radio frequency drive signal control for single- or multiple-beam scan operations. The unique module offers input laser beam power control that in turn delivers the desired scanned laser beam power shaping. Experimental results match module design theory and demonstrate a fast 5.4-micros wavelength selection speed, a low (1.53-dB) fiber-to-fiber optical insertion loss, a 5.55-nm 3-dB spectral width, and a 1500-1600-nm agile wavelength operational band.

  8. 46 CFR 182.610 - Main steering gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all...

  9. 46 CFR 182.610 - Main steering gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all...

  10. 46 CFR 182.610 - Main steering gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all...

  11. 46 CFR 182.610 - Main steering gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Main steering gear. 182.610 Section 182.610 Shipping...) MACHINERY INSTALLATION Steering Systems § 182.610 Main steering gear. (a) A vessel must be provided with a main steering gear that is: (1) Of adequate strength and capable of steering the vessel at all...

  12. Detecting genuine multipartite entanglement in steering scenarios

    NASA Astrophysics Data System (ADS)

    Jebaratnam, C.

    2016-05-01

    Einstein-Podolsky-Rosen (EPR) steering is a form of quantum nonlocality which is intermediate between entanglement and Bell nonlocality. EPR steering is a resource for quantum key distribution that is device independent on only one side in that it certifies bipartite entanglement when one party's device is not characterized while the other party's device is fully characterized. In this work, we introduce two types of genuine tripartite EPR steering, and derive two steering inequalities to detect them. In a semi-device-independent scenario where only the dimensions of two parties are assumed, the correlations which violate one of these inequalities also certify genuine tripartite entanglement. It is known that Alice can demonstrate bipartite EPR steering to Bob if and only if her measurement settings are incompatible. We demonstrate that quantum correlations can also detect tripartite EPR steering from Alice to Bob and Charlie, even if Charlie's measurement settings are compatible.

  13. Alignment and steering scenarios for the APT linac

    SciTech Connect

    Stovall, J.E.; Gray, E.R.; Nath, S.; Takeda, H.; Wood, R.L.; Young, L.M.; Crandall, K.R.

    1996-09-01

    The Accelerator for the Production of Tritium (APT) requires a very high proton beam current (100 mA cw). Requirement for hands-on maintenance limits the beam spill to less than 0.2 nA/m along most of the linac. To achieve this, it is important to understand the effects of fabrication, installation and operational errors, establish realistic tolerances, and develop techniques for mitigating their consequences. A new code, PARTREX, statistically evaluates the effects of alignment, quadrupole field, and rf phase and amplitude errors in the linac. This paper reviews the effects of quadrupole misalignments and present two steering algorithms that minimize the potential for particle loss from the beam halo. These algorithms were tested on the 8-to-20 MeV portion of the APT linac.

  14. Vehicle Steering control: A model of learning

    NASA Technical Reports Server (NTRS)

    Smiley, A.; Reid, L.; Fraser, M.

    1978-01-01

    A hierarchy of strategies were postulated to describe the process of learning steering control. Vehicle motion and steering control data were recorded for twelve novices who drove an instrumented car twice a week during and after a driver training course. Car-driver describing functions were calculated, the probable control structure determined, and the driver-alone transfer function modelled. The data suggested that the largest changes in steering control with learning were in the way the driver used the lateral position cue.

  15. Agile informatics: application of agile project management to the development of a personal health application.

    PubMed

    Chung, Jeanhee; Pankey, Evan; Norris, Ryan J

    2007-01-01

    We describe the application of the Agile method-- a short iteration cycle, user responsive, measurable software development approach-- to the project management of a modular personal health record, iHealthSpace, to be deployed to the patients and providers of a large academic primary care practice. PMID:18694014

  16. Agile informatics: application of agile project management to the development of a personal health application.

    PubMed

    Chung, Jeanhee; Pankey, Evan; Norris, Ryan J

    2007-10-11

    We describe the application of the Agile method-- a short iteration cycle, user responsive, measurable software development approach-- to the project management of a modular personal health record, iHealthSpace, to be deployed to the patients and providers of a large academic primary care practice.

  17. Light Self-Localization and Power-Dependent Steering in Anisotropic Dielectrics: Spatial Solitons in Uniaxial Nematic Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Alberucci, Alessandro; Assanto, Gaetano

    We discuss nonlinear propagation of light beams in anisotropic media, addressing the role of nonlocality and nonlinearity in power-dependent beam self-steering. With specific reference to spatial solitons in positive uniaxial nematic liquid crystals (i.e. nematicons), we describe soliton self-acceleration through reorientational response and nonlinear walk-off.

  18. Driver behavior following an automatic steering intervention.

    PubMed

    Fricke, Nicola; Griesche, Stefan; Schieben, Anna; Hesse, Tobias; Baumann, Martin

    2015-10-01

    The study investigated driver behavior toward an automatic steering intervention of a collision mitigation system. Forty participants were tested in a driving simulator and confronted with an inevitable collision. They performed a naïve drive and afterwards a repeated exposure in which they were told to hold the steering wheel loosely. In a third drive they experienced a false alarm situation. Data on driving behavior, i.e. steering and braking behavior as well as subjective data was assessed in the scenarios. Results showed that most participants held on to the steering wheel strongly or counter-steered during the system intervention during the first encounter. Moreover, subjective data collected after the first drive showed that the majority of drivers was not aware of the system intervention. Data from the repeated drive in which participants were instructed to hold the steering wheel loosely, led to significantly more participants holding the steering wheel loosely and thus complying with the instruction. This study seems to imply that without knowledge and information of the system about an upcoming intervention, the most prevalent driving behavior is a strong reaction with the steering wheel similar to an automatic steering reflex which decreases the system's effectiveness. Results of the second drive show some potential for countermeasures, such as informing drivers shortly before a system intervention in order to prevent inhibiting reactions.

  19. Classical communication cost of quantum steering

    NASA Astrophysics Data System (ADS)

    Sainz, Ana Belén; Aolita, Leandro; Brunner, Nicolas; Gallego, Rodrigo; Skrzypczyk, Paul

    2016-07-01

    Quantum steering is observed when performing appropriate local measurements on an entangled state. Here we discuss the possibility of simulating classically this effect, using classical communication instead of entanglement. We show that infinite communication is necessary for exactly simulating steering for any pure entangled state, as well as for a class of mixed entangled states. Moreover, we discuss the communication cost of steering for general entangled states, as well as approximate simulation. Our findings reveal striking differences between Bell nonlocality and steering and provide a natural way of measuring the strength of the latter.

  20. Driver behavior following an automatic steering intervention.

    PubMed

    Fricke, Nicola; Griesche, Stefan; Schieben, Anna; Hesse, Tobias; Baumann, Martin

    2015-10-01

    The study investigated driver behavior toward an automatic steering intervention of a collision mitigation system. Forty participants were tested in a driving simulator and confronted with an inevitable collision. They performed a naïve drive and afterwards a repeated exposure in which they were told to hold the steering wheel loosely. In a third drive they experienced a false alarm situation. Data on driving behavior, i.e. steering and braking behavior as well as subjective data was assessed in the scenarios. Results showed that most participants held on to the steering wheel strongly or counter-steered during the system intervention during the first encounter. Moreover, subjective data collected after the first drive showed that the majority of drivers was not aware of the system intervention. Data from the repeated drive in which participants were instructed to hold the steering wheel loosely, led to significantly more participants holding the steering wheel loosely and thus complying with the instruction. This study seems to imply that without knowledge and information of the system about an upcoming intervention, the most prevalent driving behavior is a strong reaction with the steering wheel similar to an automatic steering reflex which decreases the system's effectiveness. Results of the second drive show some potential for countermeasures, such as informing drivers shortly before a system intervention in order to prevent inhibiting reactions. PMID:26310799

  1. Agile Development Methods for Space Operations

    NASA Technical Reports Server (NTRS)

    Trimble, Jay; Webster, Chris

    2012-01-01

    Main stream industry software development practice has gone from a traditional waterfall process to agile iterative development that allows for fast response to customer inputs and produces higher quality software at lower cost. How can we, the space ops community, adopt state of the art software development practice, achieve greater productivity at lower cost, and maintain safe and effective space flight operations? At NASA Ames, we are developing Mission Control Technologies Software, in collaboration with Johnson Space Center (JSC) and, more recently, the Jet Propulsion Laboratory (JPL).

  2. Flight dynamics research for highly agile aircraft

    NASA Technical Reports Server (NTRS)

    Nguyen, Luat T.

    1989-01-01

    This paper highlights recent results of research conducted at the NASA Langley Research Center as part of a broad flight dynamics program aimed at developing technology that will enable future combat aircraft to achieve greatly enhanced agility capability at subsonic combat conditions. Studies of advanced control concepts encompassing both propulsive and aerodynamic approaches are reviewed. Dynamic stall phenomena and their potential impact on maneuvering performance and stability are summarized. Finally, issues of mathematical modeling of complex aerodynamics occurring during rapid, large amplitude maneuvers are discussed.

  3. Design, fabrication and test of the steering magnet for the KOMAC beamline

    NASA Astrophysics Data System (ADS)

    Chung, Bo-Hyun

    2015-10-01

    The Korea Multi-purpose Accelerator Complex (KOMAC) is operating a 100-MeV proton linac. The beamline facility of the KOMAC has both a 20-MeV beam and a 100-MeV beam for users. Steering magnets are added to the beamlines to adjust the position of the beam on the target. The uniformity and the harmonics of the magnetic field are computed by using the Poisson code, and the integrated magnetic field is computed by using the CST EM Studio. The designed magnets were fabricated, and the field's uniformity and the integrated field were measured. The designed and fabricated steering magnets were characterized, and the results are presented in this paper. The results are expected to improve the beam performance, in particular, accurate delivery to the target.

  4. Agile Methods for Open Source Safety-Critical Software

    PubMed Central

    Enquobahrie, Andinet; Ibanez, Luis; Cheng, Patrick; Yaniv, Ziv; Cleary, Kevin; Kokoori, Shylaja; Muffih, Benjamin; Heidenreich, John

    2011-01-01

    The introduction of software technology in a life-dependent environment requires the development team to execute a process that ensures a high level of software reliability and correctness. Despite their popularity, agile methods are generally assumed to be inappropriate as a process family in these environments due to their lack of emphasis on documentation, traceability, and other formal techniques. Agile methods, notably Scrum, favor empirical process control, or small constant adjustments in a tight feedback loop. This paper challenges the assumption that agile methods are inappropriate for safety-critical software development. Agile methods are flexible enough to encourage the right amount of ceremony; therefore if safety-critical systems require greater emphasis on activities like formal specification and requirements management, then an agile process will include these as necessary activities. Furthermore, agile methods focus more on continuous process management and code-level quality than classic software engineering process models. We present our experiences on the image-guided surgical toolkit (IGSTK) project as a backdrop. IGSTK is an open source software project employing agile practices since 2004. We started with the assumption that a lighter process is better, focused on evolving code, and only adding process elements as the need arose. IGSTK has been adopted by teaching hospitals and research labs, and used for clinical trials. Agile methods have matured since the academic community suggested they are not suitable for safety-critical systems almost a decade ago, we present our experiences as a case study for renewing the discussion. PMID:21799545

  5. A Roadmap for Using Agile Development in a Traditional Environment

    NASA Technical Reports Server (NTRS)

    Streiffert, Barbara A.; Starbird, Thomas; Grenander, Sven

    2006-01-01

    One of the newer classes of software engineering techniques is called 'Agile Development'. In Agile Development software engineers take small implementation steps and, in some cases they program in pairs. In addition, they develop automatic tests prior to implementing their small functional piece. Agile Development focuses on rapid turnaround, incremental planning, customer involvement and continuous integration. Agile Development is not the traditional waterfall method or even a rapid prototyping method (although this methodology is closer to Agile Development). At Jet Propulsion Laboratory (JPL) a few groups have begun Agile Development software implementations. The difficulty with this approach becomes apparent when Agile Development is used in an organization that has specific criteria and requirements handed down for how software development is to be performed. The work at the JPL is performed for the National Aeronautics and Space Agency (NASA). Both organizations have specific requirements, rules and procedure for developing software. This paper will discuss the some of the initial uses of the Agile Development methodology, the spread of this method and the current status of the successful incorporation into the current JPL development policies.

  6. A Roadmap for Using Agile Development in a Traditional Environment

    NASA Technical Reports Server (NTRS)

    Streiffert, Barbara; Starbird, Thomas; Grenander, Sven

    2006-01-01

    One of the newer classes of software engineering techniques is called 'Agile Development'. In Agile Development software engineers take small implementation steps and, in some cases, they program in pairs. In addition, they develop automatic tests prior to implementing their small functional piece. Agile Development focuses on rapid turnaround, incremental planning, customer involvement and continuous integration. Agile Development is not the traditional waterfall method or even a rapid prototyping method (although this methodology is closer to Agile Development). At the Jet Propulsion Laboratory (JPL) a few groups have begun Agile Development software implementations. The difficulty with this approach becomes apparent when Agile Development is used in an organization that has specific criteria and requirements handed down for how software development is to be performed. The work at the JPL is performed for the National Aeronautics and Space Agency (NASA). Both organizations have specific requirements, rules and processes for developing software. This paper will discuss some of the initial uses of the Agile Development methodology, the spread of this method and the current status of the successful incorporation into the current JPL development policies and processes.

  7. Agile manufacturing in Intelligence, Surveillance and Reconnaissance (ISR)

    NASA Astrophysics Data System (ADS)

    DiPadua, Mark; Dalton, George

    2016-05-01

    The objective of the Agile Manufacturing for Intelligence, Surveillance, and Reconnaissance (AMISR) effort is to research, develop, design and build a prototype multi-intelligence (multi-INT), reconfigurable pod demonstrating benefits of agile manufacturing and a modular open systems approach (MOSA) to make podded intelligence, surveillance, and reconnaissance (ISR) capability more affordable and operationally flexible.

  8. Peridigm summary report : lessons learned in development with agile components.

    SciTech Connect

    Salinger, Andrew Gerhard; Mitchell, John Anthony; Littlewood, David John; Parks, Michael L.

    2011-09-01

    This report details efforts to deploy Agile Components for rapid development of a peridynamics code, Peridigm. The goal of Agile Components is to enable the efficient development of production-quality software by providing a well-defined, unifying interface to a powerful set of component-based software. Specifically, Agile Components facilitate interoperability among packages within the Trilinos Project, including data management, time integration, uncertainty quantification, and optimization. Development of the Peridigm code served as a testbed for Agile Components and resulted in a number of recommendations for future development. Agile Components successfully enabled rapid integration of Trilinos packages into Peridigm. A cost of this approach, however, was a set of restrictions on Peridigm's architecture which impacted the ability to track history-dependent material data, dynamically modify the model discretization, and interject user-defined routines into the time integration algorithm. These restrictions resulted in modifications to the Agile Components approach, as implemented in Peridigm, and in a set of recommendations for future Agile Components development. Specific recommendations include improved handling of material states, a more flexible flow control model, and improved documentation. A demonstration mini-application, SimpleODE, was developed at the onset of this project and is offered as a potential supplement to Agile Components documentation.

  9. Agile Methods for Open Source Safety-Critical Software.

    PubMed

    Gary, Kevin; Enquobahrie, Andinet; Ibanez, Luis; Cheng, Patrick; Yaniv, Ziv; Cleary, Kevin; Kokoori, Shylaja; Muffih, Benjamin; Heidenreich, John

    2011-08-01

    The introduction of software technology in a life-dependent environment requires the development team to execute a process that ensures a high level of software reliability and correctness. Despite their popularity, agile methods are generally assumed to be inappropriate as a process family in these environments due to their lack of emphasis on documentation, traceability, and other formal techniques. Agile methods, notably Scrum, favor empirical process control, or small constant adjustments in a tight feedback loop. This paper challenges the assumption that agile methods are inappropriate for safety-critical software development. Agile methods are flexible enough to encourage the rightamount of ceremony; therefore if safety-critical systems require greater emphasis on activities like formal specification and requirements management, then an agile process will include these as necessary activities. Furthermore, agile methods focus more on continuous process management and code-level quality than classic software engineering process models. We present our experiences on the image-guided surgical toolkit (IGSTK) project as a backdrop. IGSTK is an open source software project employing agile practices since 2004. We started with the assumption that a lighter process is better, focused on evolving code, and only adding process elements as the need arose. IGSTK has been adopted by teaching hospitals and research labs, and used for clinical trials. Agile methods have matured since the academic community suggested they are not suitable for safety-critical systems almost a decade ago, we present our experiences as a case study for renewing the discussion.

  10. Agile Methods for Open Source Safety-Critical Software.

    PubMed

    Gary, Kevin; Enquobahrie, Andinet; Ibanez, Luis; Cheng, Patrick; Yaniv, Ziv; Cleary, Kevin; Kokoori, Shylaja; Muffih, Benjamin; Heidenreich, John

    2011-08-01

    The introduction of software technology in a life-dependent environment requires the development team to execute a process that ensures a high level of software reliability and correctness. Despite their popularity, agile methods are generally assumed to be inappropriate as a process family in these environments due to their lack of emphasis on documentation, traceability, and other formal techniques. Agile methods, notably Scrum, favor empirical process control, or small constant adjustments in a tight feedback loop. This paper challenges the assumption that agile methods are inappropriate for safety-critical software development. Agile methods are flexible enough to encourage the rightamount of ceremony; therefore if safety-critical systems require greater emphasis on activities like formal specification and requirements management, then an agile process will include these as necessary activities. Furthermore, agile methods focus more on continuous process management and code-level quality than classic software engineering process models. We present our experiences on the image-guided surgical toolkit (IGSTK) project as a backdrop. IGSTK is an open source software project employing agile practices since 2004. We started with the assumption that a lighter process is better, focused on evolving code, and only adding process elements as the need arose. IGSTK has been adopted by teaching hospitals and research labs, and used for clinical trials. Agile methods have matured since the academic community suggested they are not suitable for safety-critical systems almost a decade ago, we present our experiences as a case study for renewing the discussion. PMID:21799545

  11. Agile Bodies: A New Imperative in Neoliberal Governance

    ERIC Educational Resources Information Center

    Gillies, Donald

    2011-01-01

    Modern business discourse suggests that a key bulwark against market fluctuation and the threat of failure is for organizations to become "agile'", a more dynamic and proactive position than that previously afforded by mere "flexibility". The same idea is also directed at the personal level, it being argued that the "agile" individual is better…

  12. Correlation steering in the angularly multimode Raman atomic memory.

    PubMed

    Mazelanik, Mateusz; Dąbrowski, Michał; Wasilewski, Wojciech

    2016-09-19

    We present the possibility of steering the direction of correlations between the off-resonant Raman scattered photons from the angularly multimode atomic memory based on warm rubidium vapors. Using acousto-optic deflectors (AOD) driven by different modulation frequencies, we experimentally change the angle of incidence of the laser beams on the atomic ensemble. By performing correlation measurements for various deflection angles, we verify that we can choose the anti-Stokes light propagation direction independently of the correlated Stokes scattered light in a continuous way. As a result we can select the spatial mode of photons retrieved from the memory, which may be important for future development of quantum information processing.

  13. Mechanically-steered disk antenna for mobile satellite service

    NASA Technical Reports Server (NTRS)

    McCarrick, Charles D.

    1995-01-01

    This paper describes a low-profile disk antenna for vehicular mounting that accommodates L-Band (1525-1660.5 MHz) mobile satellite service requirements. The antenna uses a rotatable printed circuit array mechanically-steered in azimuth via an external tracking system. A shaped elevation beam inherent to the antenna design provides continuous coverage with a minimum gain of 9 dBic between elevation angles of 25-degrees and 60-degrees measured above the horizon. A brief background on the theory, design, and performance for this antenna is discussed.

  14. Introduction to Stand-up Meetings in Agile Methods

    NASA Astrophysics Data System (ADS)

    Hasnain, Eisha; Hall, Tracy

    2009-05-01

    In recent years, agile methods have become more popular in the software industry. Agile methods are a new approach compared to plan-driven approaches. One of the most important shifts in adopting an agile approach is the central focus given to people in the process. This is exemplified by the independence afforded to developers in the development work they do. This work investigates the opinions of practitioners about daily stand-up meetings in the agile methods and the role of developer in that. For our investigation we joined a yahoo group called "Extreme Programming". Our investigation suggests that although trust is an important factor in agile methods. But stand-ups are not the place to build trust.

  15. Combining Agile and Traditional: Customer Communication in Distributed Environment

    NASA Astrophysics Data System (ADS)

    Korkala, Mikko; Pikkarainen, Minna; Conboy, Kieran

    Distributed development is a radically increasing phenomenon in modern software development environments. At the same time, traditional and agile methodologies and combinations of those are being used in the industry. Agile approaches place a large emphasis on customer communication. However, existing knowledge on customer communication in distributed agile development seems to be lacking. In order to shed light on this topic and provide practical guidelines for companies in distributed agile environments, a qualitative case study was conducted in a large globally distributed software company. The key finding was that it might be difficult for an agile organization to get relevant information from a traditional type of customer organization, even though the customer communication was indicated to be active and utilized via multiple different communication media. Several challenges discussed in this paper referred to "information blackout" indicating the importance of an environment fostering meaningful communication. In order to evaluate if this environment can be created a set of guidelines is proposed.

  16. A Case Study of Coordination in Distributed Agile Software Development

    NASA Astrophysics Data System (ADS)

    Hole, Steinar; Moe, Nils Brede

    Global Software Development (GSD) has gained significant popularity as an emerging paradigm. Companies also show interest in applying agile approaches in distributed development to combine the advantages of both approaches. However, in their most radical forms, agile and GSD can be placed in each end of a plan-based/agile spectrum because of how work is coordinated. We describe how three GSD projects applying agile methods coordinate their work. We found that trust is needed to reduce the need of standardization and direct supervision when coordinating work in a GSD project, and that electronic chatting supports mutual adjustment. Further, co-location and modularization mitigates communication problems, enables agility in at least part of a GSD project, and renders the implementation of Scrum of Scrums possible.

  17. Supporting Agile Development of Authorization Rules for SME Applications

    NASA Astrophysics Data System (ADS)

    Bartsch, Steffen; Sohr, Karsten; Bormann, Carsten

    Custom SME applications for collaboration and workflow have become affordable when implemented as Web applications employing Agile methodologies. Security engineering is still difficult with Agile development, though: heavy-weight processes put the improvements of Agile development at risk. We propose Agile security engineering and increased end-user involvement to improve Agile development with respect to authorization policy development. To support the authorization policy development, we introduce a simple and readable authorization rules language implemented in a Ruby on Rails authorization plugin that is employed in a real-world SME collaboration and workflow application. Also, we report on early findings of the language’s use in authorization policy development with domain experts.

  18. A new model to compute the desired steering torque for steer-by-wire vehicles and driving simulators

    NASA Astrophysics Data System (ADS)

    Fankem, Steve; Müller, Steffen

    2014-05-01

    This paper deals with the control of the hand wheel actuator in steer-by-wire (SbW) vehicles and driving simulators (DSs). A novel model for the computation of the desired steering torque is presented. The introduced steering torque computation does not only aim to generate a realistic steering feel, which means that the driver should not miss the basic steering functionality of a modern conventional steering system such as an electric power steering (EPS) or hydraulic power steering (HPS), and this in every driving situation. In addition, the modular structure of the steering torque computation combined with suitably selected tuning parameters has the objective to offer a high degree of customisability of the steering feel and thus to provide each driver with his preferred steering feel in a very intuitive manner. The task and the tuning of each module are firstly described. Then, the steering torque computation is parameterised such that the steering feel of a series EPS system is reproduced. For this purpose, experiments are conducted in a hardware-in-the-loop environment where a test EPS is mounted on a steering test bench coupled with a vehicle simulator and parameter identification techniques are applied. Subsequently, how appropriate the steering torque computation mimics the test EPS system is objectively evaluated with respect to criteria concerning the steering torque level and gradient, the feedback behaviour and the steering return ability. Finally, the intuitive tuning of the modular steering torque computation is demonstrated for deriving a sportier steering feel configuration.

  19. 46 CFR 169.251 - Steering apparatus.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Steering apparatus. 169.251 Section 169.251 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification Inspections § 169.251 Steering apparatus. At each inspection for...

  20. 46 CFR 169.251 - Steering apparatus.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Steering apparatus. 169.251 Section 169.251 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification Inspections § 169.251 Steering apparatus. At each inspection for...

  1. 46 CFR 169.251 - Steering apparatus.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Steering apparatus. 169.251 Section 169.251 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Inspection and Certification Inspections § 169.251 Steering apparatus. At each inspection for...

  2. 49 CFR 570.7 - Steering systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... not exceed values shown in Table 1. (1) Inspection procedure. With the engine on and the wheels in the straight ahead position, turn the steering wheel in one direction until there is a perceptible movement of a front wheel. If a point on the steering wheel rim moves more than the value shown in Table...

  3. 46 CFR 176.814 - Steering systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... in suitable condition and fit for the service intended. Servo-type power systems, such as orbital... 46 Shipping 7 2011-10-01 2011-10-01 false Steering systems. 176.814 Section 176.814 Shipping COAST...) INSPECTION AND CERTIFICATION Material Inspections § 176.814 Steering systems. At each initial and...

  4. 46 CFR 115.814 - Steering systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... for the service intended. Servo-type power systems, such as orbitrol systems, must be tested and... 46 Shipping 4 2010-10-01 2010-10-01 false Steering systems. 115.814 Section 115.814 Shipping COAST... Inspections § 115.814 Steering systems. At each initial and subsequent inspection for certification the...

  5. 46 CFR 176.814 - Steering systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... in suitable condition and fit for the service intended. Servo-type power systems, such as orbital... 46 Shipping 7 2010-10-01 2010-10-01 false Steering systems. 176.814 Section 176.814 Shipping COAST...) INSPECTION AND CERTIFICATION Material Inspections § 176.814 Steering systems. At each initial and...

  6. 46 CFR 115.814 - Steering systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... for the service intended. Servo-type power systems, such as orbitrol systems, must be tested and... 46 Shipping 4 2011-10-01 2011-10-01 false Steering systems. 115.814 Section 115.814 Shipping COAST... Inspections § 115.814 Steering systems. At each initial and subsequent inspection for certification the...

  7. A practical toolkit for computational steering.

    PubMed

    Pickles, S M; Haines, R; Pinning, R L; Porter, A R

    2005-08-15

    Computational steering refers to the real-time interaction of a scientist with their running simulation code. Despite the many benefits associated with computational steering, its uptake to date has been limited. In this paper we discuss the reasons for this and how the computational steering library and associated tools developed as part of the RealityGrid project aim to tackle them. We describe the functionality of the steering library and the use of Grid services in constructing a generic, dynamic architecture for discovering, steering and connecting visualization software to running simulations. The use of on-line visualization for providing feedback to the scientist is described, including the ways in which it may be enhanced through tools such as Chromium and Access Grid. Finally, we illustrate the flexibility of our approach by describing the functionality that has been added to various simulation codes as part of the RealityGrid project.

  8. Quantifying Non-Markovianity with Temporal Steering.

    PubMed

    Chen, Shin-Liang; Lambert, Neill; Li, Che-Ming; Miranowicz, Adam; Chen, Yueh-Nan; Nori, Franco

    2016-01-15

    Einstein-Podolsky-Rosen (EPR) steering is a type of quantum correlation which allows one to remotely prepare, or steer, the state of a distant quantum system. While EPR steering can be thought of as a purely spatial correlation, there does exist a temporal analogue, in the form of single-system temporal steering. However, a precise quantification of such temporal steering has been lacking. Here, we show that it can be measured, via semidefinite programing, with a temporal steerable weight, in direct analogy to the recently proposed EPR steerable weight. We find a useful property of the temporal steerable weight in that it is a nonincreasing function under completely positive trace-preserving maps and can be used to define a sufficient and practical measure of strong non-Markovianity. PMID:26824533

  9. Steering control system for a mobile robot

    NASA Astrophysics Data System (ADS)

    Kolli, Kaylan C.; Hall, Ernest L.

    1997-09-01

    Automated guided vehicles (AGVs) have many potential applications in manufacturing, medicine, space and defense. The purpose of this paper is to describe the design of a steering mechanism for an autonomous mobile robot. The steering mechanism replaces a manually turned rack and pinion arrangement with a crank mechanism driven by a linear actuator that in turn is powered by a brushless dc motor. The system was modeled, analyzed, and redesigned to meet the requirements. A 486 computer through a 3-axis motion controller supervises the steering control. The steering motor is a brushless dc motor powered by three phase signals. It is run in current loop mode. The steering control system is supervised by a personal computer through a multi-axis motion controller. Testing of these systems has been done in the lab as well as on an outside test track with positive results.

  10. Investigation of Motorcycle Steering Torque Components

    NASA Astrophysics Data System (ADS)

    Cossalter, V.; Lot, R.; Massaro, M.; Peretto, M.

    2011-10-01

    When driving along a circular path, the rider controls a motorcycle mainly by the steering torque. This work addresses an in-depth analysis of the steady state cornering and in particular the decomposition of the motorcycle steering torque in its main components, such as road-tyre forces, gyroscopic torques, centrifugal and gravity effects. A detailed and experimentally validated multibody model of the motorcycle is used herein to analyze the steering torque components at different speeds and lateral accelerations. First the road tests are compared with the numerical results for three different vehicles and then a numerical investigation is carried out to decompose the steering torque. Finally, the effect of longitudinal acceleration and deceleration on steering torque components is presented.

  11. Switchable circular beam deflectors

    NASA Astrophysics Data System (ADS)

    Shang, Xiaobing; Joshi, Pankaj; Tan, Jin-Yi; De Smet, Jelle; Cuypers, Dieter; Baghdasaryan, Tigran; Vervaeke, Michael; Thienpont, Hugo; De Smet, Herbert

    2016-04-01

    In this work, we report two types of electrically tunable photonic devices with circularly symmetric polarization independent beam steering performance (beam condensing resp. beam broadening). The devices consist of circular micro grating structures combined with nematic liquid crystal (LC) layers with anti-parallel alignment. A single beam deflector converts a polarized and monochromatic green laser beam (λ =543.5 nm) into a diffraction pattern, with the peak intensity appearing at the third order when 0~{{V}\\text{pp}} is applied and at the zeroth order (no deflection) for voltages above 30~{{V}\\text{pp}} . Depending on the shape of the grating structure (non-inverted or inverted), the deflection is inwards or outwards. Both grating types can be made starting from the same diamond-tooled master mold. A polarized white light beam is symmetrically condensed resp. broadened over 2° in the off state and is passed through unchanged in the on state. By stacking two such devices with mutually orthogonal LC alignment layers, polarization independent switchable circular beam deflectors are realized with a high transmittance (>80%), and with the same beam steering performance as the polarization dependent single devices.

  12. SuperAGILE: The Hard X-ray Imager of AGILE

    SciTech Connect

    Feroci, M.; Costa, E.; Barbanera, L.; Del Monte, E.; Di Persio, G.; Frutti, M.; Lapshov, I.; Lazzarotto, F.; Pacciani, L.; Porrovecchio, G.; Preger, B.; Rapisarda, M.; Rubini, A.; Soffitta, P.; Tavani, M.; Mastropietro, M.; Morelli, E.; Argan, A.; Ghirlanda, G.; Mereghetti, S.

    2004-09-28

    SuperAGILE is the hard X-ray (10-40 keV) imager for the gamma-ray mission AGILE, currently scheduled for launch in mid-2005. It is based on 4 Si-microstrip detectors, with a total geometric area of 1444 cm{sup 2} (max effective about 300 cm{sup 2}), equipped with one-dimensional coded masks. The 4 detectors are perpendicularly oriented, in order to provide pairs of orthogonal one-dimensional images of the X-ray sky. The field of view of each 1-D detector is 107 deg. x 68 deg., at zero response, with an overlap in the central 68 deg. x 68 deg. area. The angular resolution on axis is 6 arcmin (pixel size). We present here the current status of the hardware development and the scientific potential for GRBs, for which an onboard trigger and imaging system will allow distributing locations through a fast communication telemetry link from AGILE to the ground.

  13. Agile: From Software to Mission System

    NASA Technical Reports Server (NTRS)

    Trimble, Jay; Shirley, Mark H.; Hobart, Sarah Groves

    2016-01-01

    The Resource Prospector (RP) is an in-situ resource utilization (ISRU) technology demonstration mission, designed to search for volatiles at the Lunar South Pole. This is NASA's first near real time tele-operated rover on the Moon. The primary objective is to search for volatiles at one of the Lunar Poles. The combination of short mission duration, a solar powered rover, and the requirement to explore shadowed regions makes for an operationally challenging mission. To maximize efficiency and flexibility in Mission System design and thus to improve the performance and reliability of the resulting Mission System, we are tailoring Agile principles that we have used effectively in ground data system software development and applying those principles to the design of elements of the mission operations system.

  14. Agility and mixed-model furniture production

    NASA Astrophysics Data System (ADS)

    Yao, Andrew C.

    2000-10-01

    The manufacture of upholstered furniture provides an excellent opportunity to analyze the effect of a comprehensive communication system on classical production management functions. The objective of the research is to study the scheduling heuristics that embrace the concepts inherent in MRP, JIT and TQM while recognizing the need for agility in a somewhat complex and demanding environment. An on-line, real-time data capture system provides the status and location of production lots, components, subassemblies for schedule control. Current inventory status of raw material and purchased items are required in order to develop and adhere to schedules. For the large variety of styles and fabrics customers may order, the communication system must provide timely, accurate and comprehensive information for intelligent decisions with respect to the product mix and production resources.

  15. Wavelength agile holmium-doped fiber laser

    NASA Astrophysics Data System (ADS)

    Simakov, N.; Daniel, J. M. O.; Ward, J.; Clarkson, W. A.; Hemming, A.; Haub, J.

    2016-03-01

    For the first time, an electronically-controlled, wavelength-agile tuneable holmium-doped fibre laser is presented. A narrow-band acousto-optic tuneable filter was characterized and used as the wavelength selective element to avoid any inertial effects associated with opto-mechanical tuning mechanisms. We demonstrate operation over a 90 nm wavelength range spanning 2040 - 2130 nm. The laser produced >150 mW over this entire range with a signal-to-noise ratio of >45 dB and line-width of ~0.16 nm. Switching times of ~35 μs and sweep rates of up to 9 nm/ms were also demonstrated.

  16. Broadband time reversed acoustic focusing and steering system

    NASA Astrophysics Data System (ADS)

    Sutin, Alexander; Sarvazyan, Armen; Montaldo, Gabriel; Palacio, Delphine; Bercoff, Jeremy; Tanter, Mickael; Fink, Mathias

    2001-05-01

    We present results of experimental testing and theoretical modeling of a time reversal acoustic (TRA) focusing system based on a multifaceted aluminum resonator with 15 piezoceramic transducers glued to the resonator facets. One of the facets of the resonator, a pentagon with characteristic dimension of about 30 mm, was submerged into a water tank and served as a virtual phased array which provided ultrasound focusing and beam steering in a wide frequency band (0.7-3 MHz). Ultrasonic pulses with different carrier frequencies and various complex waveforms were focused; the focal length was varied in the range of 10-55 mm and the focused beam was steered in a range of angles of +/-60 deg. The amplitude of the signal in the focal region reached 40 MPa. A theoretical model was based on an assumption that the radiating part of the resonator works as a phase conjugation screen for a spherical wave radiated from the focal point. Theoretical dependencies of the field structure on the position of the focus point and ultrasound frequency are in a good agreement with experimental results. TRA based focusing of ultrasound has numerous applications in medical diagnostics, surgery and therapy. [Work supported by NIH grant.

  17. Agile parallel bioinformatics workflow management using Pwrake

    PubMed Central

    2011-01-01

    Background In bioinformatics projects, scientific workflow systems are widely used to manage computational procedures. Full-featured workflow systems have been proposed to fulfil the demand for workflow management. However, such systems tend to be over-weighted for actual bioinformatics practices. We realize that quick deployment of cutting-edge software implementing advanced algorithms and data formats, and continuous adaptation to changes in computational resources and the environment are often prioritized in scientific workflow management. These features have a greater affinity with the agile software development method through iterative development phases after trial and error. Here, we show the application of a scientific workflow system Pwrake to bioinformatics workflows. Pwrake is a parallel workflow extension of Ruby's standard build tool Rake, the flexibility of which has been demonstrated in the astronomy domain. Therefore, we hypothesize that Pwrake also has advantages in actual bioinformatics workflows. Findings We implemented the Pwrake workflows to process next generation sequencing data using the Genomic Analysis Toolkit (GATK) and Dindel. GATK and Dindel workflows are typical examples of sequential and parallel workflows, respectively. We found that in practice, actual scientific workflow development iterates over two phases, the workflow definition phase and the parameter adjustment phase. We introduced separate workflow definitions to help focus on each of the two developmental phases, as well as helper methods to simplify the descriptions. This approach increased iterative development efficiency. Moreover, we implemented combined workflows to demonstrate modularity of the GATK and Dindel workflows. Conclusions Pwrake enables agile management of scientific workflows in the bioinformatics domain. The internal domain specific language design built on Ruby gives the flexibility of rakefiles for writing scientific workflows. Furthermore, readability

  18. Thinking Outside the Box: Agile Business Models for CNOs

    NASA Astrophysics Data System (ADS)

    Loss, Leandro; Crave, Servane

    This paper introduces the idea of an agile Business Model for CNOs grounded on a new model of innovation based on the effects of globalization and of Knowledge Economy. The agile Business Model considers the resources that are spread out and available worldwide as well as the need for each customer to receive a unique customer experience. It aims at reinforcing in the context of the Knowledge Economy the different business models approaches developed so far. The paper also identifies the levers and the barriers of Agile Business Models Innovation in CNOs.

  19. Agile rediscovering values: Similarities to continuous improvement strategies

    NASA Astrophysics Data System (ADS)

    Díaz de Mera, P.; Arenas, J. M.; González, C.

    2012-04-01

    Research in the late 80's on technological companies that develop products of high value innovation, with sufficient speed and flexibility to adapt quickly to changing market conditions, gave rise to the new set of methodologies known as Agile Management Approach. In the current changing economic scenario, we considered very interesting to study the similarities of these Agile Methodologies with other practices whose effectiveness has been amply demonstrated in both the West and Japan. Strategies such as Kaizen, Lean, World Class Manufacturing, Concurrent Engineering, etc, would be analyzed to check the values they have in common with the Agile Approach.

  20. Moving target detection for frequency agility radar by sparse reconstruction

    NASA Astrophysics Data System (ADS)

    Quan, Yinghui; Li, YaChao; Wu, Yaojun; Ran, Lei; Xing, Mengdao; Liu, Mengqi

    2016-09-01

    Frequency agility radar, with randomly varied carrier frequency from pulse to pulse, exhibits superior performance compared to the conventional fixed carrier frequency pulse-Doppler radar against the electromagnetic interference. A novel moving target detection (MTD) method is proposed for the estimation of the target's velocity of frequency agility radar based on pulses within a coherent processing interval by using sparse reconstruction. Hardware implementation of orthogonal matching pursuit algorithm is executed on Xilinx Virtex-7 Field Programmable Gata Array (FPGA) to perform sparse optimization. Finally, a series of experiments are performed to evaluate the performance of proposed MTD method for frequency agility radar systems.

  1. GRB 070724B: the first Gamma Ray Burst localized by SuperAGILE

    SciTech Connect

    Del Monte, E.; Costa, E.; Donnarumma, I.; Feroci, M.; Lapshov, I.; Lazzarotto, F.; Soffitta, P.; Argan, A.; Pucella, G.; Trois, A.; Vittorini, V.; Evangelista, Y.; Rapisarda, M.; Barbiellini, G.; Longo, F.; Basset, M.; Foggetta, L.; Vallazza, E.; Bulgarelli, A.; Di Cocco, G.

    2008-05-22

    GRB070724B is the first Gamma Ray Burst localized by the SuperAGILE instrument aboard the AGILE space mission. The SuperAGILE localization has been confirmed after the after-glow observation by the XRT aboard the Swift satellite. No significant gamma ray emission above 50 MeV has been detected for this GRB. In this paper we describe the SuperAGILE capabilities in detecting Gamma Ray Burst and the AGILE observation of GRB 070724B.

  2. The mechanical ground support equipment for the AIV and calibration of the AGILE integrated payload

    NASA Astrophysics Data System (ADS)

    Trifoglio, Massimo; Traci, Alessandro; Gianotti, Fulvio; Bulgarelli, Andrea; Di Cocco, Guido; Labanti, Claudio; Celesti, Enrico; Mauri, Alessandro

    2004-10-01

    AGILE is an ASI (Italian Space Agency) Small Space Mission for high energy astrophysics in the range 30 MeV - 50 GeV which is planned to be launched in 2005. Mechanical equipments are required for the Assembly, Integration and Verification (AIV) of the various subsystems together, forming the Payload complement. Furthermore, the calibration of the AGILE's performances requires to test with a beam line and with discrete X and γ ray sources the instrument response as a function of the energy of the incoming photons and particles and of their inclination with respect to the instrument axis. These AIV and Calibration activities lead to require an ad hoc Mechanical Ground Support Equipment (MGSE) which is able to move the instrument up and down, left and right as well as to rotate the instrument around the vertical axes and to tilt it by an angle between 0 and 180° with reference to the direction of the beam. We present here the MGSE we have designed in order to provide these functionalities with the required performances, and taking into account the working environment of the AIV and calibration sites.

  3. 46 CFR 169.623 - Power-driven steering systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Power-driven steering systems. 169.623 Section 169.623... Machinery and Electrical Steering Systems § 169.623 Power-driven steering systems. (a) Power-driven steering... system must automatically resume operation after an electric power outage. (b) Control of...

  4. 46 CFR 108.641 - Instructions for changing steering gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  5. 46 CFR 108.641 - Instructions for changing steering gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  6. 46 CFR 108.641 - Instructions for changing steering gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Instructions for changing steering gear. 108.641 Section... steering gear. Instructions stating, in order, the different steps to be taken for changing to emergency and secondary steering gear must be posted in the steering gear room and at each secondary...

  7. 49 CFR 393.209 - Steering wheel systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Steering wheel systems. 393.209 Section 393.209... NECESSARY FOR SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems § 393.209 Steering wheel systems. (a) The steering wheel shall be secured and must not have any...

  8. 49 CFR 393.209 - Steering wheel systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Steering wheel systems. 393.209 Section 393.209... NECESSARY FOR SAFE OPERATION Frames, Cab and Body Components, Wheels, Steering, and Suspension Systems § 393.209 Steering wheel systems. (a) The steering wheel shall be secured and must not have any...

  9. 46 CFR 169.623 - Power-driven steering systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Power-driven steering systems. 169.623 Section 169.623... Machinery and Electrical Steering Systems § 169.623 Power-driven steering systems. (a) Power-driven steering... system must automatically resume operation after an electric power outage. (b) Control of...

  10. 46 CFR 169.623 - Power-driven steering systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Power-driven steering systems. 169.623 Section 169.623... Machinery and Electrical Steering Systems § 169.623 Power-driven steering systems. (a) Power-driven steering... system must automatically resume operation after an electric power outage. (b) Control of...

  11. 46 CFR 169.623 - Power-driven steering systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Power-driven steering systems. 169.623 Section 169.623... Machinery and Electrical Steering Systems § 169.623 Power-driven steering systems. (a) Power-driven steering... system must automatically resume operation after an electric power outage. (b) Control of...

  12. 46 CFR 169.623 - Power-driven steering systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Power-driven steering systems. 169.623 Section 169.623... Machinery and Electrical Steering Systems § 169.623 Power-driven steering systems. (a) Power-driven steering... system must automatically resume operation after an electric power outage. (b) Control of...

  13. Adjustment procedure for beam alignment in scanned ion-beam therapy

    NASA Astrophysics Data System (ADS)

    Saraya, Y.; Takeshita, E.; Furukawa, T.; Hara, Y.; Mizushima, K.; Saotome, N.; Tansho, R.; Shirai, T.; Noda, K.

    2016-09-01

    Control of the beam position for three-dimensional pencil-beam scanning is important because the position accuracy of the beam significantly impacts the alignment of the irradiation field. To suppress this effect, we have developed a simple procedure for beamline tuning. At first, beamline tuning is performed with steering magnets and fluorescent screen monitors to converge the beam's trajectory to a central orbit. Misalignment between the beam's position and the reference axis is checked by using the verification system, which consists of a screen monitor and an acrylic phantom. If the beam position deviates from the reference axis, two pairs of steering magnets, which are placed on downstream of the beam transport line, will be corrected. These adjustments are iterated until the deviations for eleven energies of the beam are within 0.5 mm of the reference axis. To demonstrate the success of our procedure, we used our procedure to perform beam commissioning at the Kanagawa Cancer Center.

  14. Relativistic particle beams for interstellar propulsion

    NASA Astrophysics Data System (ADS)

    Nordley, Gerald D.

    1993-04-01

    The concept of pellet-stream propulsion proposed by Singer (1980) is extended to particle beams and relativistic velocities. A simple relativistic mission study is presented, and it is shown how certain technological developments might enhance the concept. In particular, considerations discussed include beam drivers; beam cooling, steering, and focusing; beam driven mission mechanics; and the radiation problem. The energy issues are also briefly considered.

  15. Frequency agile OPO-based transmitters for multiwavelength DIAL

    SciTech Connect

    Velsko, S.P.; Ruggiero, A.; Herman, M.

    1996-09-01

    We describe a first generation mid-infrared transmitter with pulse to pulse frequency agility and both wide and narrow band capability. This transmitter was used to make multicomponent Differential Absorption LIDAR (DIAL) measurements in the field.

  16. Value Creation by Agile Projects: Methodology or Mystery?

    NASA Astrophysics Data System (ADS)

    Racheva, Zornitza; Daneva, Maya; Sikkel, Klaas

    Business value is a key concept in agile software development approaches. This paper presents results of a systematic review of literature on how business value is created by agile projects. We found that with very few exceptions, most published studies take the concept of business value for granted and do not state what it means in general as well as in the specific study context. We could find no study which clearly indicates how exactly individual agile practices or groups of those create value and keep accumulating it over time. The key implication for research is that we have an incentive to pursue the study of value creation in agile project by deploying empirical research methods.

  17. Pilot users in agile development processes: motivational factors.

    PubMed

    Johannessen, Liv Karen; Gammon, Deede

    2010-01-01

    Despite a wealth of research on user participation, few studies offer insights into how to involve multi-organizational users in agile development methods. This paper is a case study of user involvement in developing a system for electronic laboratory requisitions using agile methodologies in a multi-organizational context. Building on an interpretive approach, we illuminate questions such as: How does collaboration between users and developers evolve and how might it be improved? What key motivational aspects are at play when users volunteer and continue contributing in the face of considerable added burdens? The study highlights how agile methods in themselves appear to facilitate mutually motivating collaboration between user groups and developers. Lessons learned for leveraging the advantages of agile development processes include acknowledging the substantial and ongoing contributions of users and their roles as co-designers of the system. PMID:20543366

  18. An Approach for Prioritizing Agile Practices for Adaptation

    NASA Astrophysics Data System (ADS)

    Mikulenas, Gytenis; Kapocius, Kestutis

    Agile software development approaches offer a strong alternative to the traditional plan-driven methodologies that have not been able to warrant successfulness of the software projects. However, the move toward Agile is often hampered by the wealth of alternative practices that are accompanied by numerous success or failure stories. Clearly, the formal methods for choosing most suitable practices are lacking. In this chapter, we present an overview of this problem and propose an approach for prioritization of available practices in accordance to the particular circumstances. The proposal combines ideas from Analytic Hierarchy Process (AHP) decision-making technique, cost-value analysis, and Rule-Description-Practice (RDP) technique. Assumption that such approach could facilitate the Agile adaptation process was supported by the case study of the approach illustrating the process of choosing most suitable Agile practices within a real-life project.

  19. Frequency agile OPO-based transmitters for multiwavelength DIAL

    SciTech Connect

    Velsko, S.P.; Ruggiero, A.; Herman, M.

    1996-09-01

    We describe a first generation mid-infrared transmitter with pulse-to- pulse frequency agility and both wide and narrow band capability. This transmitter was used to make multicomponent DIAL measurements in the field.

  20. Investigation into the impact of agility on conceptual fighter design

    NASA Technical Reports Server (NTRS)

    Engelbeck, R. M.

    1995-01-01

    The Agility Design Study was performed by the Boeing Defense and Space Group for the NASA Langley Research Center. The objective of the study was to assess the impact of agility requirements on new fighter configurations. Global trade issues investigated were the level of agility, the mission role of the aircraft (air-to-ground, multi-role, or air-to-air), and whether the customer is Air force, Navy, or joint service. Mission profiles and design objectives were supplied by NASA. An extensive technology assessment was conducted to establish the available technologies to industry for the aircraft. Conceptual level methodology is presented to assess the five NASA-supplied agility metrics. Twelve configurations were developed to address the global trade issues. Three-view drawings, inboard profiles, and performance estimates were made and are included in the report. A critical assessment and lessons learned from the study are also presented.

  1. Laterality and performance of agility-trained dogs.

    PubMed

    Siniscalchi, Marcello; Bertino, Daniele; Quaranta, Angelo

    2014-01-01

    Correlations between lateralised behaviour and performance were investigated in 19 agility-trained dogs (Canis familiaris) by scoring paw preference to hold a food object and relating it to performance during typical agility obstacles (jump/A-frame and weave poles). In addition, because recent behavioural studies reported that visual stimuli of emotional valence presented to one visual hemifield at a time affect visually guided motor responses in dogs, the possibility that the position of the owner respectively in the left and in the right canine visual hemifield might be associated with quality of performance during agility was considered. Dogs' temperament was also measured by an owner-rated questionnaire. The most relevant finding was that agility-trained dogs displayed longer latencies to complete the obstacles with the owner located in their left visual hemifield compared to the right. Interestingly, the results showed that this phenomenon was significantly linked to both dogs' trainability and the strength of paw preference.

  2. Pilot users in agile development processes: motivational factors.

    PubMed

    Johannessen, Liv Karen; Gammon, Deede

    2010-01-01

    Despite a wealth of research on user participation, few studies offer insights into how to involve multi-organizational users in agile development methods. This paper is a case study of user involvement in developing a system for electronic laboratory requisitions using agile methodologies in a multi-organizational context. Building on an interpretive approach, we illuminate questions such as: How does collaboration between users and developers evolve and how might it be improved? What key motivational aspects are at play when users volunteer and continue contributing in the face of considerable added burdens? The study highlights how agile methods in themselves appear to facilitate mutually motivating collaboration between user groups and developers. Lessons learned for leveraging the advantages of agile development processes include acknowledging the substantial and ongoing contributions of users and their roles as co-designers of the system.

  3. Modern Enterprise Systems as Enablers of Agile Development

    NASA Astrophysics Data System (ADS)

    Fredriksson, Odd; Ljung, Lennart

    Traditional ES technology and traditional project management methods are supporting and matching each other. But they are not supporting the critical success conditions for ES development in an effective way. Although the findings from one case study of a successful modern ES change project is not strong empirical evidence, we carefully propose that the new modern ES technology is supporting and matching agile project management methods. In other words, it provides the required flexibility which makes it possible to put into practice the agile way of running projects, both for the system supplier and for the customer. In addition, we propose that the combination of modern ES technology and agile project management methods are more appropriate for supporting the realization of critical success conditions for ES development. The main purpose of this chapter is to compare critical success conditions for modern enterprise systems development projects with critical success conditions for agile information systems development projects.

  4. New approaches to enhance active steering system functionalities: preliminary results

    NASA Astrophysics Data System (ADS)

    Serarslan, Benan

    2014-09-01

    An important development of the steering systems in general is active steering systems like active front steering and steer-by-wire systems. In this paper the current functional possibilities in application of active steering systems are explored. A new approach and additional functionalities are presented that can be implemented to the active steering systems without additional hardware such as new sensors and electronic control units. Commercial active steering systems are controlling the steering angle depending on the driving situation only. This paper introduce methods for enhancing active steering system functionalities depending not only on the driving situation but also vehicle parameters like vehicle mass, tyre and road condition. In this regard, adaptation of the steering ratio as a function of above mentioned vehicle parameters is presented with examples. With some selected vehicle parameter changes, the reduction of the undesired influences on vehicle dynamics of these parameter changes has been demonstrated theoretically with simulations and with real-time driving measurements.

  5. Enhanced frequency agility of high-power relativistic backward wave oscillators

    SciTech Connect

    Moreland, L.D.; Schamiloglu, E.; Lemke, R.W.; Roitman, A.M.; Korovin, S.D.; Rostov, V.V.

    1996-06-01

    This paper describes how finite length effects in high-power backward wave oscillators can be exploited in a controlled manner to achieve enhanced frequency agility. Experiments were performed using a Sinus-6 high-power relativistic repetitively pulsed electron beam accelerator. A uniform slow wave structure was used in these studies and its parameters were fixed. Sections of smooth-walled circular waveguide of varying lengths were inserted both before and after the slow wave structure. Variations in the length of smooth-walled waveguide on the order of a quarter-wavelength of the generated electromagnetic radiation were found to significantly affect both microwave frequency and radiation efficiency in a periodic-like manner. The experimental results were reproduced in TWOQUICK electromagnetic particle-in-cell simulations. A bandwidth of about 500 MHz centered around 9.5 GHz at hundreds of MW power levels has been achieved with constant beam and slow wave structure parameters.

  6. Frequency-agile kilohertz repetition-rate optical parametric oscillator based on periodically poled lithium niobate

    SciTech Connect

    Yang, S.T.; Velsko, S.P.

    1999-02-01

    We report kilohertz repetition-rate pulse-to-pulse wavelength tuning from 3.22 to 3.7 {mu}m in a periodically poled lithium niobate (PPLN) optical parametric oscillator (OPO). Rapid tuning over 400thinspcm{sup {minus}1} with random wavelength accessibility is achieved by rotation of the pump beam angle by no more than 24thinspthinspmrad in the PPLN crystal by use of an acousto-optic beam deflector. Over the entire tuning range, a near-transform-limited OPO bandwidth can be obtained by means of injection seeding with a single-frequency 1.5-{mu}m laser diode. The frequency agility, high repetition rate, and narrow bandwidth of this mid-IR PPLN OPO make it well suited as a lidar transmitter source. {copyright} {ital 1999} {ital Optical Society of America}

  7. Automatic steering corrections to minimize injection oscillations in the Fermilab Antiproton Source rings

    SciTech Connect

    Harding, D.J.; Riddiford, A.W.

    1989-03-01

    Missteering of particle beam at injection into a circular accelerator produces coherent betatron oscillations. The beam position monitor system in the Antiproton Source at Fermilab can measure the beam position on each turn around the ring during these oscillations. From the amplitude and phase of the oscillations, corrections to the beamline steering are calculated to remove the oscillations. The analysis includes the case where the horizontal and vertical tunes are quite strongly coupled. This technique has proved to be valuable both in operation of the Fermilab Collider and as an analytical tool. 4 refs., 2 figs.

  8. 46 CFR 176.814 - Steering systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Steering systems. 176.814 Section 176.814 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS... hydraulic pumps secured....

  9. 46 CFR 176.814 - Steering systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Steering systems. 176.814 Section 176.814 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS... hydraulic pumps secured....

  10. 46 CFR 176.814 - Steering systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Steering systems. 176.814 Section 176.814 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS (UNDER 100 GROSS TONS... hydraulic pumps secured....

  11. The impact of flying qualities on helicopter operational agility

    NASA Technical Reports Server (NTRS)

    Padfield, Gareth D.; Lappos, Nick; Hodgkinson, John

    1993-01-01

    Flying qualities standards are formally set to ensure safe flight and therefore reflect minimum, rather than optimum, requirements. Agility is a flying quality but relates to operations at high, if not maximum, performance. While the quality metrics and test procedures for flying, as covered for example in ADS33C, may provide an adequate structure to encompass agility, they do not currently address flight at high performance. This is also true in the fixed-wing world and a current concern in both communities is the absence of substantiated agility criteria and possible conflicts between flying qualities and high performance. AGARD is sponsoring a working group (WG19) title 'Operational Agility' that deals with these and a range of related issues. This paper is condensed from contributions by the three authors to WG19, relating to flying qualities. Novel perspectives on the subject are presented including the agility factor, that quantifies performance margins in flying qualities terms; a new parameter, based on maneuver acceleration is introduced as a potential candidate for defining upper limits to flying qualities. Finally, a probabilistic analysis of pilot handling qualities ratings is presented that suggests a powerful relationship between inherent airframe flying qualities and operational agility.

  12. Adaptive projection method applied to three-dimensional ultrasonic focusing and steering through the ribs.

    PubMed

    Cochard, E; Aubry, J F; Tanter, M; Prada, C

    2011-08-01

    An adaptive projection method for ultrasonic focusing through the rib cage, with minimal energy deposition on the ribs, was evaluated experimentally in 3D geometry. Adaptive projection is based on decomposition of the time-reversal operator (DORT method) and projection on the "noise" subspace. It is shown that 3D implementation of this method is straightforward, and not more time-consuming than 2D. Comparisons are made between adaptive projection, spherical focusing, and a previously proposed time-reversal focusing method, by measuring pressure fields in the focal plane and rib region using the three methods. The ratio of the specific absorption rate at the focus over the one at the ribs was found to be increased by a factor of up to eight, versus spherical emission. Beam steering out of geometric focus was also investigated. For all configurations projecting steered emissions were found to deposit less energy on the ribs than steering time-reversed emissions: thus the non-invasive method presented here is more efficient than state-of-the-art invasive techniques. In fact, this method could be used for real-time treatment, because a single acquisition of back-scattered echoes from the ribs is enough to treat a large volume around the focus, thanks to real time projection of the steered beams.

  13. Emittance growth from electron beam modulation

    SciTech Connect

    Blaskiewicz, M.

    2009-12-01

    In linac ring colliders like MeRHIC and eRHIC a modulation of the electron bunch can lead to a modulation of the beam beam tune shift and steering errors. These modulations can lead to emittance growth. This note presents simple formulas to estimate these effects which generalize some previous results.

  14. "Agile" Battery Technology Transfer-Lessons Learnt

    NASA Astrophysics Data System (ADS)

    Sabatini, P.; Annoni, G.; Grossi, R.; Alia, Sergio; Reulier, David

    2008-09-01

    AGILE, the high energy astrophysics mission of the Italian Space Agency launched on April 23rd 2007, is the first LEO satellite to be powered by Saft's commercially available space qualified MPS176065 rechargeable lithium ion batteries.Saft and Carlo Gavazzi Space (CGS) have achieved a successful technology transfer replacing Ni-H2 batteries with high energy lithium ion batteries in a full speed program (4 months) and with a cost effective approach. The battery system comprises 2 x 24 Saft MPS176065 space qualified Li-ion cells in an 8s3p configuration (3 parallel arrays each composed by 8 series cell) with a nominal capacity of 2 x 480 Wh and an integral autonomous cell balancing system that ensures the maximum possible battery life.The MPS176065 space qualified cell is based on Saft's well proven MP series of prismatic rechargeable Li-ion batteries. It offers an extremely high capacity made possible by the stainless steel prismatic container that makes use of the volume which is otherwise lost when conventional cylindrical cells are packed together. A single prismatic cell has about 20% more volumetric energy density than an equivalent pack of cylindrical cells.

  15. Agile robotic edge finishing system research

    SciTech Connect

    Powell, M.A.

    1995-07-01

    This paper describes a new project undertaken by Sandia National Laboratories to develop an agile, automated, high-precision edge finishing system. The project has a two-year duration and was initiated in October, 1994. This project involves re-designing and adding additional capabilities to an existing finishing workcell at Sandia; and developing intelligent methods for automating process definition and for controlling finishing processes. The resulting system will serve as a prototype for systems that will be deployed into highly flexible automated production lines. The production systems will be used to produce a wide variety of products with limited production quantities and quick turnaround requirements. The prototype system is designed to allow programming, process definition, fixture re-configuration, and process verification to be performed off-line for new products. CAD/CAM (Computer Aided Design/Computer Aided Manufacturing) models of the part will be used to assist with the automated process development and process control tasks. To achieve Sandia`s performance goals, the system will be employ advanced path planning, burr prediction expert systems, automated process definition, statistical process models in a process database, and a two-level control scheme using hybrid position-force control and fuzzy logic control. In this paper, we discuss the progress and the planned system development under this project.

  16. Distributed agile software development for the SKA

    NASA Astrophysics Data System (ADS)

    Wicenec, Andreas; Parsons, Rebecca; Kitaeff, Slava; Vinsen, Kevin; Wu, Chen; Nelson, Paul; Reed, David

    2012-09-01

    The SKA software will most probably be developed by many groups distributed across the globe and coming from dierent backgrounds, like industries and research institutions. The SKA software subsystems will have to cover a very wide range of dierent areas, but still they have to react and work together like a single system to achieve the scientic goals and satisfy the challenging data ow requirements. Designing and developing such a system in a distributed fashion requires proper tools and the setup of an environment to allow for ecient detection and tracking of interface and integration issues in particular in a timely way. Agile development can provide much faster feedback mechanisms and also much tighter collaboration between the customer (scientist) and the developer. Continuous integration and continuous deployment on the other hand can provide much faster feedback of integration issues from the system level to the subsystem developers. This paper describes the results obtained from trialing a potential SKA development environment based on existing science software development processes like ALMA, the expected distribution of the groups potentially involved in the SKA development and experience gained in the development of large scale commercial software projects.

  17. Poststatistic steering wind estimation in the troposphere and lower stratosphere

    NASA Astrophysics Data System (ADS)

    Palmer, Robert D.; Larsen, Miguel F.; Sheppard, E. Lamar; Fukao, Shoichiro; Yamamoto, Mamoru; Tsuda, Toshitaka; Kato, Susumu

    1993-05-01

    Poststatistic steering (PSS) techniques are applied for estimating the wind vector. Since spatially separated receivers can be used to synthesize a radar beam in an arbitrary direction, Doppler beam swinging (DBS) techniques can be used in conjunction with PSS to obtain estimates of the wind vector. Data obtained with the middle and upper atmosphere (MU) radar in Japan are used to implement the technique in the troposphere and lower stratosphere at a VHF wavelength. To obtain an accurate estimate of the beam-pointing direction, the synthesized two-way antenna pattern is calculated. Also, the effects of aspect sensitivity on this technique are explored. The mode of operation of the MU radar was alternated between a typical DBS mode and a spatial interferometric (SI) mode, which was used for the PSS technique. Results from the PSS method of obtaining the wind vector are compared to the DBS results, which are assumed to be an accurate representation of the atmospheric wind. This study suggests that aspect sensitivity causes an underestimate of the horizontal wind using PSS. Corrections were made using the aspect sensitivity functions obtained from the DBS experiment and the corrected PSS velocities compare well with the DBS velocities. The vertical velocity estimate using a vertically pointing beam is shown to possess a gravity wave characteristic which is due solely to contamination from the horizontal wind.

  18. View aft of compartment D23, aft steering station; note steering ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View aft of compartment D-23, aft steering station; note steering unit with crosshead and shaft bearing supports. Note framing supports for armored protective deck at top of photo. (p60) - USS Olympia, Penn's Landing, 211 South Columbus Boulevard, Philadelphia, Philadelphia County, PA

  19. The agile alert system for gamma-ray transients

    SciTech Connect

    Bulgarelli, A.; Trifoglio, M.; Gianotti, F.; Fioretti, V.; Chen, A. W.; Pittori, C.; Verrecchia, F.; Lucarelli, F.; Santolamazza, P.; Fanari, G.; Giommi, P.; Pellizzoni, A.; and others

    2014-01-20

    In recent years, a new generation of space missions has offered great opportunities for discovery in high-energy astrophysics. In this article we focus on the scientific operations of the Gamma-Ray Imaging Detector (GRID) on board the AGILE space mission. AGILE-GRID, sensitive in the energy range of 30 MeV-30 GeV, has detected many γ-ray transients of both galactic and extragalactic origin. This work presents the AGILE innovative approach to fast γ-ray transient detection, which is a challenging task and a crucial part of the AGILE scientific program. The goals are to describe (1) the AGILE Gamma-Ray Alert System, (2) a new algorithm for blind search identification of transients within a short processing time, (3) the AGILE procedure for γ-ray transient alert management, and (4) the likelihood of ratio tests that are necessary to evaluate the post-trial statistical significance of the results. Special algorithms and an optimized sequence of tasks are necessary to reach our goal. Data are automatically analyzed at every orbital downlink by an alert pipeline operating on different timescales. As proper flux thresholds are exceeded, alerts are automatically generated and sent as SMS messages to cellular telephones, via e-mail, and via push notifications from an application for smartphones and tablets. These alerts are crosschecked with the results of two pipelines, and a manual analysis is performed. Being a small scientific-class mission, AGILE is characterized by optimization of both scientific analysis and ground-segment resources. The system is capable of generating alerts within two to three hours of a data downlink, an unprecedented reaction time in γ-ray astrophysics.

  20. The AGILE Alert System for Gamma-Ray Transients

    NASA Astrophysics Data System (ADS)

    Bulgarelli, A.; Trifoglio, M.; Gianotti, F.; Tavani, M.; Parmiggiani, N.; Fioretti, V.; Chen, A. W.; Vercellone, S.; Pittori, C.; Verrecchia, F.; Lucarelli, F.; Santolamazza, P.; Fanari, G.; Giommi, P.; Beneventano, D.; Argan, A.; Trois, A.; Scalise, E.; Longo, F.; Pellizzoni, A.; Pucella, G.; Colafrancesco, S.; Conforti, V.; Tempesta, P.; Cerone, M.; Sabatini, P.; Annoni, G.; Valentini, G.; Salotti, L.

    2014-01-01

    In recent years, a new generation of space missions has offered great opportunities for discovery in high-energy astrophysics. In this article we focus on the scientific operations of the Gamma-Ray Imaging Detector (GRID) on board the AGILE space mission. AGILE-GRID, sensitive in the energy range of 30 MeV-30 GeV, has detected many γ-ray transients of both galactic and extragalactic origin. This work presents the AGILE innovative approach to fast γ-ray transient detection, which is a challenging task and a crucial part of the AGILE scientific program. The goals are to describe (1) the AGILE Gamma-Ray Alert System, (2) a new algorithm for blind search identification of transients within a short processing time, (3) the AGILE procedure for γ-ray transient alert management, and (4) the likelihood of ratio tests that are necessary to evaluate the post-trial statistical significance of the results. Special algorithms and an optimized sequence of tasks are necessary to reach our goal. Data are automatically analyzed at every orbital downlink by an alert pipeline operating on different timescales. As proper flux thresholds are exceeded, alerts are automatically generated and sent as SMS messages to cellular telephones, via e-mail, and via push notifications from an application for smartphones and tablets. These alerts are crosschecked with the results of two pipelines, and a manual analysis is performed. Being a small scientific-class mission, AGILE is characterized by optimization of both scientific analysis and ground-segment resources. The system is capable of generating alerts within two to three hours of a data downlink, an unprecedented reaction time in γ-ray astrophysics.

  1. Beam Shaping for CARS Measurements in Turbulent Environments

    NASA Technical Reports Server (NTRS)

    Magnotti, Gaetano; Cutler, Andrew D.; Danehy, Paul M.

    2010-01-01

    This paper describes a new technique to mitigate the effect of beam steering on CARS measurements in turbulent, variable density environments. The new approach combines Planar BOXCARS phase-matching with elliptical shaping of one of the beams to generate a signal insensitive to beam steering, while keeping the same spatial resolution. Numerical and experimental results are provided to demonstrate the effectiveness of this approach. One set of experiments investigated the effect of beam shaping in the presence of a controlled and well quantified displacement of the beams at the focal plane. Another set of experiments, more qualitative, proved the effectiveness of the technique in the presence of severe beam steering due to turbulence.

  2. The Southern Argentine Agile Meteor Radar (SAAMER)

    NASA Astrophysics Data System (ADS)

    Janches, Diego

    2014-11-01

    The Southern Argentina Agile Meteor Radar (SAAMER) is a new generation system deployed in Rio Grande, Tierra del Fuego, Argentina (53 S) in May 2008. SAAMER transmits 10 times more power than regular meteor radars, and uses a newly developed transmitting array, which focuses power upward instead of the traditional single-antenna-all-sky configuration. The system is configured such that the transmitter array can also be utilized as a receiver. The new design greatly increases the sensitivity of the radar enabling the detection of large number of particles at low zenith angles. The more concentrated transmitted power enables additional meteor studies besides those typical of these systems based on the detection of specular reflections, such as routine detections of head echoes and non-specular trails, previously only possible with High Power and Large Aperture radars. In August 2010, SAAMER was upgraded to a system capable to determine meteoroid orbital parameters. This was achieved by adding two remote receiving stations approximately 10 km away from the main site in near perpendicular directions. The upgrade significantly expands the science that is achieved with this new radar enabling us to study the orbital properties of the interplanetary dust environment. Because of the unique geographical location, SAAMER allows for additional inter-hemispheric comparison with measurements from Canadian Meteor Orbit Radar, which is geographically conjugate. Initial surveys show, for example, that SAAMER observes a very strong contribution of the South Toroidal Sporadic meteor source, of which limited observational data is available. In addition, SAAMER offers similar unique capabilities for meteor showers and streams studies given the range of ecliptic latitudes that the system enables detailed study of showers at high southern latitudes (e.g July Phoenicids or Puppids complex). Finally, SAAMER is ideal for the deployment of complementary instrumentation in both, permanent

  3. Microfluidic plug steering using surface acoustic waves.

    PubMed

    Sesen, Muhsincan; Alan, Tuncay; Neild, Adrian

    2015-07-21

    Digital microfluidic systems, in which isolated droplets are dispersed in a carrier medium, offer a method to study biological assays and chemical reactions highly efficiently. However, it's challenging to manipulate these droplets in closed microchannel devices. Here, we present a method to selectively steer plugs (droplets with diameters larger than the channel's width) at a specially designed Y-junction within a microfluidic chip. The method makes use of surface acoustic waves (SAWs) impinging on a multiphase interface in which an acoustic contrast is present. As a result, the liquid-liquid interface is subjected to acoustic radiation forces. These forces are exploited to steer plugs into selected branches of the Y-junction. Furthermore, the input power can be finely tuned to split a plug into two uneven plugs. The steering of plugs as a whole, based on plug volume and velocity is thoroughly characterized. The results indicate that there is a threshold plug volume after which the steering requires elevated electrical energy input. This plug steering method can easily be integrated to existing lab-on-a-chip devices and it offers a robust and active plug manipulation technique in closed microchannels.

  4. Microfluidic plug steering using surface acoustic waves.

    PubMed

    Sesen, Muhsincan; Alan, Tuncay; Neild, Adrian

    2015-07-21

    Digital microfluidic systems, in which isolated droplets are dispersed in a carrier medium, offer a method to study biological assays and chemical reactions highly efficiently. However, it's challenging to manipulate these droplets in closed microchannel devices. Here, we present a method to selectively steer plugs (droplets with diameters larger than the channel's width) at a specially designed Y-junction within a microfluidic chip. The method makes use of surface acoustic waves (SAWs) impinging on a multiphase interface in which an acoustic contrast is present. As a result, the liquid-liquid interface is subjected to acoustic radiation forces. These forces are exploited to steer plugs into selected branches of the Y-junction. Furthermore, the input power can be finely tuned to split a plug into two uneven plugs. The steering of plugs as a whole, based on plug volume and velocity is thoroughly characterized. The results indicate that there is a threshold plug volume after which the steering requires elevated electrical energy input. This plug steering method can easily be integrated to existing lab-on-a-chip devices and it offers a robust and active plug manipulation technique in closed microchannels. PMID:26079216

  5. Design of beam steering electronic circuits for medical applications

    NASA Astrophysics Data System (ADS)

    Safar, Mohammad A. A. A.

    This thesis deals with the theory and design of a hemispherical antenna array circuit that is capable to operate in the intermediate zones. By doing that, this array can be used in Hyperthermia Treatment for Brain Cancer in which the aim is to noninvasively focus the fields at microwave frequencies to the location of the tumor cells in the brain. Another possible application of the array is to offer an alternative means of sustaining Deep Brain Stimulation other than using the traditional (surgical) approach. The new noninvasive technique is accomplished by the use of a hemispherical antenna array placed on the human's head. The array uses a new beamforming technique that achieves 3 dimensional beamforming or focusing of the magnetic field of antennas to desired points in the brain to achieve either cell death by temperature rise (Hyperthermia Application) or to cause brain stimulation and hopefully alleviate the affects of Parkinson's Disease (Deep Brain Stimulation). The main obstacle in this design was that the far field approximation that is usually used when designing antenna arrays does not apply in this case since the hemispherical array is in close proximity to where the magnetic field is desired to be focused. The antenna array problem is approached as a boundary-valued problem with the human head being modeled as a three layered hemisphere. The exact expressions for electromagnetic fields are derived. Health issues such as electric field exposure and specific absorption rate (SAR) are considered. After developing the main antenna and beamforming theory, a neural network is designed to accomplish the beamforming technique used. The radio-frequency (RF) transmitter was designed to transmit the fields at a frequency of 1.8 GHz. The antenna array can also be used as a receiver. The antenna and beamforming theory is presented. A new reception technique is shown which enables the array to receive multiple magnetic field sources from within the hemispherical surface. The receiver is designed to operate at 500 kHz with the RF receiver circuit designed to receive any signal from within the hemispherical surface at a frequency of 500 kHz.

  6. Correlation steering in the angularly multimode Raman atomic memory.

    PubMed

    Mazelanik, Mateusz; Dąbrowski, Michał; Wasilewski, Wojciech

    2016-09-19

    We present the possibility of steering the direction of correlations between the off-resonant Raman scattered photons from the angularly multimode atomic memory based on warm rubidium vapors. Using acousto-optic deflectors (AOD) driven by different modulation frequencies, we experimentally change the angle of incidence of the laser beams on the atomic ensemble. By performing correlation measurements for various deflection angles, we verify that we can choose the anti-Stokes light propagation direction independently of the correlated Stokes scattered light in a continuous way. As a result we can select the spatial mode of photons retrieved from the memory, which may be important for future development of quantum information processing. PMID:27661934

  7. MSAT-X electronically steered phased array antenna system

    NASA Technical Reports Server (NTRS)

    Chung, H. H.; Foy, W.; Schaffner, G.; Pagels, W.; Vayner, M.; Nelson, J.; Peng, S. Y.

    1988-01-01

    A low profile electronically steered phased array was successfully developed for the Mobile Satellite Experiment Program (MSAT-X). The newly invented cavity-backed printed crossed-slot was used as the radiating element. The choice of this element was based on its low elevation angle gain coverage and low profile. A nineteen-way radial type unequal power divider and eighteen three-bit diode phase shifters constitute the beamformer module which is used to scan the beams electronically. A complete hybrid mode pointing system was also developed. The major features of the antenna system are broad coverage, low profile, and fast acquisition and tracking performance, even under fading conditions. Excellent intersatellite isolation (better than 26 dB) was realized, which will provide good quality mobile satellite communication in the future.

  8. Role of thermal noise in tripartite quantum steering

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Gong, Qihuang; Ficek, Zbigniew; He, Qiongyi

    2014-08-01

    The influence of thermal noise on bipartite and tripartite quantum steering induced by a short laser pulse in a hybrid three-mode optomechanical system is investigated. The calculation is carried out under the bad cavity limit, the adiabatic approximation of a slowly varying amplitude of the cavity mode, and with the assumption of driving the cavity mode with a blue detuned strong laser pulse. Under such conditions, explicit expressions of the bipartite and tripartite steering parameters are obtained, and the concept of collective tripartite quantum steering, recently introduced by He and Reid [Phys. Rev. Lett. 111, 250403 (2013), 10.1103/PhysRevLett.111.250403], is clearly explored. It is found that both bipartite and tripartite steering parameters are sensitive functions of the initial state of the modes and distinctly different steering behavior could be observed depending on whether the modes were initially in a thermal state or not. For the modes initially in a vacuum state, the bipartite and tripartite steering occur simultaneously over the entire interaction time. This indicates that collective tripartite steering cannot be achieved. The collective steering can be achieved for the modes initially prepared in a thermal state. We find that the initial thermal noise is more effective in destroying the bipartite rather than the tripartite steering which, on the other hand, can persist even for a large thermal noise. For the initial vacuum state of a steered mode, the tripartite steering exists over the entire interaction time even if the steering modes are in very noisy thermal states. When the steered mode is initially in a thermal state, it can be collectively steered by the other modes. There are thresholds for the average number of the thermal photons above which the existing tripartite steering appears as the collective steering. Finally, we point out that the collective steering may provide a resource in a hybrid quantum network for quantum secret sharing

  9. Development of a Computer Program for Analyzing Preliminary Aircraft Configurations in Relationship to Emerging Agility Metrics

    NASA Technical Reports Server (NTRS)

    Bauer, Brent

    1993-01-01

    This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition, one study illustrates the module's ability to optimize a configuration's agility performance.

  10. Analysis and optimization of preliminary aircraft configurations in relationship to emerging agility metrics

    NASA Technical Reports Server (NTRS)

    Sandlin, Doral R.; Bauer, Brent Alan

    1993-01-01

    This paper discusses the development of a FORTRAN computer code to perform agility analysis on aircraft configurations. This code is to be part of the NASA-Ames ACSYNT (AirCraft SYNThesis) design code. This paper begins with a discussion of contemporary agility research in the aircraft industry and a survey of a few agility metrics. The methodology, techniques and models developed for the code are then presented. Finally, example trade studies using the agility module along with ACSYNT are illustrated. These trade studies were conducted using a Northrop F-20 Tigershark aircraft model. The studies show that the agility module is effective in analyzing the influence of common parameters such as thrust-to-weight ratio and wing loading on agility criteria. The module can compare the agility potential between different configurations. In addition one study illustrates the module's ability to optimize a configuration's agility performance.

  11. Unbounded Violation of Quantum Steering Inequalities.

    PubMed

    Marciniak, M; Rutkowski, A; Yin, Z; Horodecki, M; Horodecki, R

    2015-10-23

    We construct steering inequalities that exhibit unbounded violation. The concept was to exploit the relationship between steering violation and the uncertainty relation. To this end, we apply mutually unbiased bases and anticommuting observables, known to exhibit the strongest uncertainty. In both cases, we are able to procure unbounded violations. Our approach is much more constructive and transparent than the operator space theory approach employed to obtain large violation of Bell inequalities. Importantly, using anticommuting observables we are able to obtain a dichotomic steering inequality with unbounded violation. Thus far, there is no analogous result for Bell inequalities. Interestingly, both the dichotomic inequality and one of our inequalities cannot be directly obtained from existing uncertainty relations, which strongly suggest the existence of an unknown kind of uncertainty relation.

  12. Aeroelastic Tailoring via Tow Steered Composites

    NASA Technical Reports Server (NTRS)

    Stanford, Bret K.; Jutte, Christine V.

    2014-01-01

    The use of tow steered composites, where fibers follow prescribed curvilinear paths within a laminate, can improve upon existing capabilities related to aeroelastic tailoring of wing structures, though this tailoring method has received relatively little attention in the literature. This paper demonstrates the technique for both a simple cantilevered plate in low-speed flow, as well as the wing box of a full-scale high aspect ratio transport configuration. Static aeroelastic stresses and dynamic flutter boundaries are obtained for both cases. The impact of various tailoring choices upon the aeroelastic performance is quantified: curvilinear fiber steering versus straight fiber steering, certifiable versus noncertifiable stacking sequences, a single uniform laminate per wing skin versus multiple laminates, and identical upper and lower wing skins structures versus individual tailoring.

  13. Stability analysis of automobile driver steering control

    NASA Technical Reports Server (NTRS)

    Allen, R. W.

    1981-01-01

    In steering an automobile, the driver must basically control the direction of the car's trajectory (heading angle) and the lateral deviation of the car relative to a delineated pathway. A previously published linear control model of driver steering behavior which is analyzed from a stability point of view is considered. A simple approximate expression for a stability parameter, phase margin, is derived in terms of various driver and vehicle control parameters, and boundaries for stability are discussed. A field test study is reviewed that includes the measurement of driver steering control parameters. Phase margins derived for a range of vehicle characteristics are found to be generally consistent with known adaptive properties of the human operator. The implications of these results are discussed in terms of driver adaptive behavior.

  14. Influence of different shoulder-elbow configurations on steering precision and steering velocity in automotive context.

    PubMed

    Schmidt, Susanne; Seiberl, Wolfgang; Schwirtz, Ansgar

    2015-01-01

    Ergonomic design requirements are needed to develop optimum vehicle interfaces for the driver. The majority of the current specifications consider only anthropometric conditions and subjective evaluations of comfort. This paper examines specific biomechanical aspects to improve the current ergonomic requirements. Therefore, a research which involved 40 subjects was carried out to obtain more knowledge in the field of steering movement while driving a car. Five different shoulder-elbow joint configurations were analyzed using a driving simulator to find optimum posture for driving in respect of steering precision and steering velocity. Therefore, a 20 s precision test and a test to assess maximum steering velocity over a range of 90° steering motion have been conducted. The results show that driving precision, as well as maximum steering velocity, are significantly increased in mid-positions (elbow angles of 95° and 120°) compared to more flexed (70°) or extended (145° and 160°) postures. We conclude that driver safety can be enhanced by implementing these data in the automotive design process because faster and highly precise steering can be important during evasive actions and in accident situations. In addition, subjective comfort rating, analyzed with questionnaires, confirmed experimental results. PMID:25168195

  15. Influence of different shoulder-elbow configurations on steering precision and steering velocity in automotive context.

    PubMed

    Schmidt, Susanne; Seiberl, Wolfgang; Schwirtz, Ansgar

    2015-01-01

    Ergonomic design requirements are needed to develop optimum vehicle interfaces for the driver. The majority of the current specifications consider only anthropometric conditions and subjective evaluations of comfort. This paper examines specific biomechanical aspects to improve the current ergonomic requirements. Therefore, a research which involved 40 subjects was carried out to obtain more knowledge in the field of steering movement while driving a car. Five different shoulder-elbow joint configurations were analyzed using a driving simulator to find optimum posture for driving in respect of steering precision and steering velocity. Therefore, a 20 s precision test and a test to assess maximum steering velocity over a range of 90° steering motion have been conducted. The results show that driving precision, as well as maximum steering velocity, are significantly increased in mid-positions (elbow angles of 95° and 120°) compared to more flexed (70°) or extended (145° and 160°) postures. We conclude that driver safety can be enhanced by implementing these data in the automotive design process because faster and highly precise steering can be important during evasive actions and in accident situations. In addition, subjective comfort rating, analyzed with questionnaires, confirmed experimental results.

  16. Decision Support for Iteration Scheduling in Agile Environments

    NASA Astrophysics Data System (ADS)

    Szőke, Ákos

    Today’s software business development projects often lay claim to low-risk value to the customers in order to be financed. Emerging agile processes offer shorter investment periods, faster time-to-market and better customer satisfaction. To date, however, in agile environments there is no sound methodological schedule support contrary to the traditional plan-based approaches. To address this situation, we present an agile iteration scheduling method whose usefulness is evaluated with post-mortem simulation. It demonstrates that the method can significantly improve load balancing of resources (cca. 5×), produce higher quality and lower-risk feasible schedule, and provide more informed and established decisions by optimized schedule production. Finally, the paper analyzes benefits and issues from the use of this method.

  17. Architected Agile Solutions for Software-Reliant Systems

    NASA Astrophysics Data System (ADS)

    Boehm, Barry; Lane, Jo Ann; Koolmanojwong, Supannika; Turner, Richard

    Systems are becoming increasingly reliant on software due to needs for rapid fielding of “70% capabilities,” interoperability, net-centricity, and rapid adaptation to change. The latter need has led to increased interest in agile methods of software development, in which teams rely on shared tacit interpersonal knowledge rather than explicit documented knowledge. However, such systems often need to be scaled up to higher level of performance and assurance, requiring stronger architectural support. Several organizations have recently transformed themselves by developing successful combinations of agility and architecture that can scale to projects of up to 100 personnel. This chapter identifies a set of key principles for such architected agile solutions for software-reliant systems, provides guidance for how much architecting is enough, and illustrates the key principles with several case studies.

  18. Onshore and Offshore Outsourcing with Agility: Lessons Learned

    NASA Astrophysics Data System (ADS)

    Kussmaul, Clifton

    This chapter reflects on case study based an agile distributed project that ran for approximately three years (from spring 2003 to spring 2006). The project involved (a) a customer organization with key personnel distributed across the US, developing an application with rapidly changing requirements; (b) onshore consultants with expertise in project management, development processes, offshoring, and relevant technologies; and (c) an external offsite development team in a CMM-5 organization in southern India. This chapter is based on surveys and discussions with multiple participants. The several years since the project was completed allow greater perspective on both the strengths and weaknesses, since the participants can reflect on the entire life of the project, and compare it to subsequent experiences. Our findings emphasize the potential for agile project management in distributed software development, and the importance of people and interactions, taking many small steps to find and correct errors, and matching the structures of the project and product to support implementation of agility.

  19. The AGILE Mission and Gamma-Ray Bursts

    SciTech Connect

    Longo, Francesco; Tavani, M.; Barbiellini, G.; Argan, A.; Basset, M.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P.; Chen, A.; Costa, E.; Del Monte, E.; Di Cocco, G.; Di Persio, G.; Donnarumma, I.; Feroci, M.; Fiorini, M.; Foggetta, L.; Froysland, T.; Frutti, M.

    2007-05-01

    The AGILE Mission will explore the gamma-ray Universe with a very innovative instrument combining for the first time a gamma-ray imager and a hard X-ray imager. AGILE will be operational at the beginning of 2007 and it will provide crucial data for the study of Active Galactic Nuclei, Gamma-Ray Bursts, unidentified gamma-ray sources, Galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing. The AGILE instrument is designed to simultaneously detect and image photons in the 30 MeV - 50 GeV and 15 - 45 keV energy bands with excellent imaging and timing capabilities, and a large field of view covering {approx} 1/5 of the entire sky at energies above 30 MeV. A CsI calorimeter is capable of GRB triggering in the energy band 0.3-50 MeV. The broadband detection of GRBs and the study of implications for particle acceleration and high energy emission are primary goals of the mission. AGILE can image GRBs with 2-3 arcminute error boxes in the hard X-ray range, and provide broadband photon-by photon detection in the 15-45 keV, 03-50 MeV, and 30 MeV-30 GeV energy ranges. Microsecond on-board photon tagging and a {approx} 100 microsecond gamma-ray detection deadtime will be crucial for fast GRB timing. On-board calculated GRB coordinates and energy fluxes will be quickly transmitted to the ground by an ORBCOMM transceiver. AGILE is now (January 2007) undergoing final satellite integration and testing. The PLS V launch is planned in spring 2007. AGILE is then foreseen to be fully operational during the summer of 2007.

  20. 22. Steering gear box and wheel from starboard side. Mizzen ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. Steering gear box and wheel from starboard side. Mizzen boom has been removed for repairs (note boom cradle just forward of steering gear box). - Schooner C.A. THAYER, Hyde Street Pier, San Francisco, San Francisco County, CA

  1. Experimental Quantification of Asymmetric Einstein-Podolsky-Rosen Steering.

    PubMed

    Sun, Kai; Ye, Xiang-Jun; Xu, Jin-Shi; Xu, Xiao-Ye; Tang, Jian-Shun; Wu, Yu-Chun; Chen, Jing-Ling; Li, Chuan-Feng; Guo, Guang-Can

    2016-04-22

    Einstein-Podolsky-Rosen (EPR) steering describes the ability of one observer to nonlocally "steer" the other observer's state through local measurements. EPR steering exhibits a unique asymmetric property; i.e., the steerability can differ between observers, which can lead to one-way EPR steering in which only one observer obtains steerability in the steering process. This property is inherently different from the symmetric concepts of entanglement and Bell nonlocality, and it has attracted increasing interest. Here, we experimentally demonstrate asymmetric EPR steering for a class of two-qubit states in the case of two measurement settings. We propose a practical method to quantify the steerability. We then provide a necessary and sufficient condition for EPR steering and clearly demonstrate one-way EPR steering. Our work provides new insight into the fundamental asymmetry of quantum nonlocality and has potential applications in asymmetric quantum information processing.

  2. 9 CFR 78.6 - Steers and spayed heifers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Restrictions on Interstate Movement of Cattle Because of Brucellosis § 78.6 Steers and spayed heifers. Steers and spayed heifers may be moved interstate in accordance with 9 CFR part 86 and without...

  3. 102. STEERING GEAR ROOM FORWARD LOOKING AFT ON STARBOARD ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    102. STEERING GEAR ROOM - FORWARD LOOKING AFT ON STARBOARD SIDE SHOWING RUDDER POST, HYDRAULIC RAM, EMERGENCY STEERING PUMP PIPING AND REMOTE OPERATING LINKAGE. - U.S.S. HORNET, Puget Sound Naval Shipyard, Sinclair Inlet, Bremerton, Kitsap County, WA

  4. Pilothouse bridge with steering gear at center, ship's wheel has ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Pilothouse bridge with steering gear at center, ship's wheel has been removed. Vertical shaft is connected to flying bridge steering wheel. - Purse Seiner SHENANDOAH, Gig Harbor Peninsula Historical Society and Museum, Gig Harbor, Pierce County, WA

  5. Digital Beam Deflectors Based Partly on Liquid Crystals

    NASA Technical Reports Server (NTRS)

    Pouch, John J.; Miranda, Felix A.; Kreminska, Liubov; Pishnyak, Oleg; Golovin, Andrii; Winker, Bruce K.

    2007-01-01

    A digital beam deflector based partly on liquid crystals has been demonstrated as a prototype of a class of optical beam-steering devices that contain no mechanical actuators or solid moving parts. Such beam-steering devices could be useful in a variety of applications, including free-space optical communications, switching in fiber-optic communications, general optical switching, and optical scanning. Liquid crystals are of special interest as active materials in nonmechanical beam steerers and deflectors because of their structural flexibility, low operating voltages, and the relatively low costs of fabrication of devices that contain them.

  6. Steering in spin tomographic probability representation

    NASA Astrophysics Data System (ADS)

    Man'ko, V. I.; Markovich, L. A.

    2016-09-01

    The steering property known for two-qubit state in terms of specific inequalities for the correlation function is translated for the state of qudit with the spin j = 3 / 2. Since most steering detection inequalities are based on the correlation functions we introduce analogs of such functions for the single qudit systems. The tomographic probability representation for the qudit states is applied. The connection between the correlation function in the two-qubit system and the single qudit is presented in an integral form with an intertwining kernel calculated explicitly in tomographic probability terms.

  7. A steering mechanism for phototaxis in Chlamydomonas.

    PubMed

    Bennett, Rachel R; Golestanian, Ramin

    2015-03-01

    Chlamydomonas shows both positive and negative phototaxis. It has a single eyespot near its equator, and as the cell rotates during the forward motion, the light signal received by the eyespot varies. We use a simple mechanical model of Chlamydomonas that couples the flagellar beat pattern to the light intensity at the eyespot to demonstrate a mechanism for phototactic steering that is consistent with observations. The direction of phototaxis is controlled by a parameter in our model, and the steering mechanism is robust to noise. Our model shows switching between directed phototaxis when the light is on and run-and-tumble behaviour in the dark.

  8. A steering mechanism for phototaxis in Chlamydomonas

    PubMed Central

    Bennett, Rachel R.; Golestanian, Ramin

    2015-01-01

    Chlamydomonas shows both positive and negative phototaxis. It has a single eyespot near its equator, and as the cell rotates during the forward motion, the light signal received by the eyespot varies. We use a simple mechanical model of Chlamydomonas that couples the flagellar beat pattern to the light intensity at the eyespot to demonstrate a mechanism for phototactic steering that is consistent with observations. The direction of phototaxis is controlled by a parameter in our model, and the steering mechanism is robust to noise. Our model shows switching between directed phototaxis when the light is on and run-and-tumble behaviour in the dark. PMID:25589576

  9. Biorobotics: using robots to emulate and investigate agile locomotion.

    PubMed

    Ijspeert, Auke J

    2014-10-10

    The graceful and agile movements of animals are difficult to analyze and emulate because locomotion is the result of a complex interplay of many components: the central and peripheral nervous systems, the musculoskeletal system, and the environment. The goals of biorobotics are to take inspiration from biological principles to design robots that match the agility of animals, and to use robots as scientific tools to investigate animal adaptive behavior. Used as physical models, biorobots contribute to hypothesis testing in fields such as hydrodynamics, biomechanics, neuroscience, and prosthetics. Their use may contribute to the design of prosthetic devices that more closely take human locomotion principles into account.

  10. Agile radio resource management for proactive wireless networking (Invited Paper)

    NASA Astrophysics Data System (ADS)

    Brothers, L. Reggie; MacMullan, Samuel J.; Brown, Kevin L.; DeBardelaben, James A.

    2005-05-01

    Current military operational effectiveness can degrade rapidly with increasing communications stresses such as heavy throughput and QoS demands from disadvantaged users exposed to severe channel impairments and communications threats. This paper proposes a distributed and agile radio resource management (RRM) system to maintain mission effectiveness even under significant communications stress. Agile RRM includes a well-coordinated cross-layer design with the introduction of new OSI layer features and interactions as well as methods to incorporate communications constraints and requirements in systems controlling mission planning and execution.

  11. Lean and Agile Development of the AITS Ground Software System

    NASA Astrophysics Data System (ADS)

    Richters, Mark; Dutruel, Etienne; Mecredy, Nicolas

    2013-08-01

    We present the ongoing development of a new ground software system used for integrating, testing and operating spacecraft. The Advanced Integration and Test Services (AITS) project aims at providing a solution for electrical ground support equipment and mission control systems in future Astrium Space Transportation missions. Traditionally ESA ground or flight software development projects are conducted according to a waterfall-like process as specified in the ECSS-E-40 standard promoted by ESA in the European industry. In AITS a decision was taken to adopt an agile development process. This work could serve as a reference for future ESA software projects willing to apply agile concepts.

  12. Design and performance test of a two-axis fast steering mirror driven by piezoelectric actuators

    NASA Astrophysics Data System (ADS)

    Fang, Chu; Guo, Jin; Yang, Guo-qing; Jiang, Zhen-hua; Xu, Xin-hang; Wang, Ting-feng

    2016-09-01

    A novel design of a two-axis fast steering mirror (FSM) with piezoelectric actuators is proposed for incoherent laser beam combination. The mechanical performance of the FSM is tested. The results show that the tilting range of the mirror is about 4 mrad, and the 1st-order resonance frequency is about 250 Hz. A self-designed grating encoder is taken as the sensor, which ensures the optimal precision of 10 μrad. The novel mechanical design can meet the requirement of engineering in incoherent laser beam combination.

  13. Steering and positioning targets for HWIL IR testing at cryogenic conditions

    NASA Astrophysics Data System (ADS)

    Perkes, D. W.; Jensen, G. L.; Higham, D. L.; Lowry, H. S.; Simpson, W. R.

    2006-05-01

    In order to increase the fidelity of hardware-in-the-loop ground-truth testing, it is desirable to create a dynamic scene of multiple, independently controlled IR point sources. ATK-Mission Research has developed and supplied the steering mirror systems for the 7V and 10V Space Simulation Test Chambers at the Arnold Engineering Development Center (AEDC), Air Force Materiel Command (AFMC). A portion of the 10V system incorporates multiple target sources beam-combined at the focal point of a 20K cryogenic collimator. Each IR source consists of a precision blackbody with cryogenic aperture and filter wheels mounted on a cryogenic two-axis translation stage. This point source target scene is steered by a high-speed steering mirror to produce further complex motion. The scene changes dynamically in order to simulate an actual operational scene as viewed by the System Under Test (SUT) as it executes various dynamic look-direction changes during its flight to a target. Synchronization and real-time hardware-in-the-loop control is accomplished using reflective memory for each subsystem control and feedback loop. This paper focuses on the steering mirror system and the required tradeoffs of optical performance, precision, repeatability and high-speed motion as well as the complications of encoder feedback calibration and operation at 20K.

  14. 49 CFR 393.209 - Steering wheel systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... following parameters: Steering wheel diameter Manual steering system Power steering system 406 mm or less (16 inches or less) 51 mm (2 inches) 108 mm (41/4 inches). 457 mm (18 inches) 57 mm (21/4 inches) 121 mm (43/4 inches). 483 mm (19 inches) 60 mm (23/8 inches) 127 mm (5 inches). 508 mm (20 inches) 64...

  15. 49 CFR 393.209 - Steering wheel systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... following parameters: Steering wheel diameter Manual steering system Power steering system 406 mm or less (16 inches or less) 51 mm (2 inches) 108 mm (41/4 inches). 457 mm (18 inches) 57 mm (21/4 inches) 121 mm (43/4 inches). 483 mm (19 inches) 60 mm (23/8 inches) 127 mm (5 inches). 508 mm (20 inches) 64...

  16. 46 CFR 167.65-25 - Steering gear tests.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means...

  17. 46 CFR 61.20-1 - Steering gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  18. 46 CFR 61.20-1 - Steering gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  19. 46 CFR 167.65-25 - Steering gear tests.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means...

  20. 46 CFR 167.65-25 - Steering gear tests.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means...

  1. 46 CFR 61.20-1 - Steering gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  2. 46 CFR 167.65-25 - Steering gear tests.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Steering gear tests. 167.65-25 Section 167.65-25... SHIPS Special Operating Requirements § 167.65-25 Steering gear tests. On all nautical school ships making voyages of more than 48 hours' duration, the entire steering gear, the whistle, the means...

  3. 46 CFR 61.20-1 - Steering gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  4. 46 CFR 61.20-1 - Steering gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Steering gear. 61.20-1 Section 61.20-1 Shipping COAST... Periodic Tests of Machinery and Equipment § 61.20-1 Steering gear. (a) The marine inspector must inspect the steering gear at each inspection for certification for vessels whose Certificate of...

  5. 9 CFR 78.21 - Bison steers and spayed heifers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 9 Animals and Animal Products 1 2011-01-01 2011-01-01 false Bison steers and spayed heifers. 78.21... Restrictions on Interstate Movement of Bison Because of Brucellosis § 78.21 Bison steers and spayed heifers. Bison steers and spayed heifers may be moved interstate without restriction under this subpart....

  6. 9 CFR 78.21 - Bison steers and spayed heifers.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 9 Animals and Animal Products 1 2012-01-01 2012-01-01 false Bison steers and spayed heifers. 78.21... Restrictions on Interstate Movement of Bison Because of Brucellosis § 78.21 Bison steers and spayed heifers. Bison steers and spayed heifers may be moved interstate without restriction under this subpart....

  7. 9 CFR 78.21 - Bison steers and spayed heifers.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 9 Animals and Animal Products 1 2013-01-01 2013-01-01 false Bison steers and spayed heifers. 78.21... Restrictions on Interstate Movement of Bison Because of Brucellosis § 78.21 Bison steers and spayed heifers. Bison steers and spayed heifers may be moved interstate without restriction under this subpart....

  8. 9 CFR 78.21 - Bison steers and spayed heifers.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 9 Animals and Animal Products 1 2014-01-01 2014-01-01 false Bison steers and spayed heifers. 78.21... Restrictions on Interstate Movement of Bison Because of Brucellosis § 78.21 Bison steers and spayed heifers. Bison steers and spayed heifers may be moved interstate without further restriction under this subpart....

  9. 9 CFR 78.21 - Bison steers and spayed heifers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 9 Animals and Animal Products 1 2010-01-01 2010-01-01 false Bison steers and spayed heifers. 78.21... Restrictions on Interstate Movement of Bison Because of Brucellosis § 78.21 Bison steers and spayed heifers. Bison steers and spayed heifers may be moved interstate without restriction under this subpart....

  10. 14 CFR 23.745 - Nose/tail wheel steering.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Nose/tail wheel steering. 23.745 Section 23.745 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must...

  11. 14 CFR 23.745 - Nose/tail wheel steering.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Nose/tail wheel steering. 23.745 Section 23.745 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must...

  12. 14 CFR 23.745 - Nose/tail wheel steering.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Nose/tail wheel steering. 23.745 Section 23.745 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must...

  13. 14 CFR 23.745 - Nose/tail wheel steering.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Nose/tail wheel steering. 23.745 Section 23.745 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must...

  14. 14 CFR 23.745 - Nose/tail wheel steering.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Nose/tail wheel steering. 23.745 Section 23.745 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT... Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must...

  15. 46 CFR 182.620 - Auxiliary means of steering.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Auxiliary means of steering. 182.620 Section 182.620... TONS) MACHINERY INSTALLATION Steering Systems § 182.620 Auxiliary means of steering. (a) Except as provided in paragraph (c) of this section, a vessel must be provided with an auxiliary means of...

  16. 46 CFR 182.620 - Auxiliary means of steering.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Auxiliary means of steering. 182.620 Section 182.620... TONS) MACHINERY INSTALLATION Steering Systems § 182.620 Auxiliary means of steering. (a) Except as provided in paragraph (c) of this section, a vessel must be provided with an auxiliary means of...

  17. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... steering linkage shall not exceed the values shown in Table 3. (1) Inspection procedure. Elevate the front... are correctly adjusted. Grasp the front and rear of a tire and attempt to turn the tire and wheel assemble left and right. If the free movement at the front or rear tread of the tire exceeds the...

  18. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... steering linkage shall not exceed the values shown in Table 3. (1) Inspection procedure. Elevate the front... are correctly adjusted. Grasp the front and rear of a tire and attempt to turn the tire and wheel assemble left and right. If the free movement at the front or rear tread of the tire exceeds the...

  19. Robust steering control of spacecraft carrier rockets

    NASA Astrophysics Data System (ADS)

    Correa, Adriana Elysa Alimandro; da Rosa, Alex; Ferreira, Henrique Cezar; Ishihara, Joao Yoshiyuki; Borges, Renato Alves; Sheptun, Yuri Dmitrievich

    In the year of 2003 it was established a cooperation agreement between Ukraine and Brazil for utilization of Cyclone-4 launch vehicle at Alcantara Launch Center. The company responsible for the marketing and operation of launch services is the company bi-national Alcantara Cyclone Space (ACS). The Cyclone-4 launch vehicle is the newest version of the Ukrainian Cyclone family launchers developed by Yuzhnoye State Design Office. This family has been used for many successful spacecrafts launches since 1969. This paper is concerned with the yaw stabilization problem around a nominal trajectory for the third stage of a satellite carrier rocket similar to the Cyclone-4. Only the steering machine of the main engine is considered as actuator. The dynamic behavior of the third stage around the nominal trajectory is modeled as a fourthorder time-varying linear system whereas the steering machine is modeled as a linear dynamical system up to third order. The values of the parameters of the steering machine model are unknown, however belonging to known intervals. As the main result, the stabilization problem is solved with a proportional derivative (PD) controller. The proposed tuning approach takes into account the robustness of the controller with respect to the steering machine model uncertainties. The performance of the PD controller is demonstrated by simulation results.

  20. Ultramaneuverable steering control algorithms for terrain transitions

    NASA Astrophysics Data System (ADS)

    Torrie, Mel W.; Koch, Ralf; Bahl, Vikas; Cripps, Don

    1999-07-01

    The Center for Self-Organizing and Intelligent Systems has built several vehicles with ultra-maneuverable steering capability. Each drive wheel on the vehicle can be independently set at any angle with respect to the vehicle body and the vehicles can rotate or translate in any direction. The vehicles are expected to operate on a wide range of terrain surfaces and problems arise in effectively controlling changes in wheel steering angles as the vehicle transitions from one extreme running surface to another. Controllers developed for smooth surfaces may not perform well on rough or 'sticky' surfaces and vice versa. The approach presented involves the development of a model of the steering motor with the static and viscous friction of the steering motor load included. The model parameters are then identified through a series of environmental tests using a vehicle wheel assembly and the model thus obtained is used for control law development. Four different robust controllers were developed and evaluated through simulation and vehicle testing. The findings of this development will be presented.

  1. Controlled Structures Technology Steering Committee Workshop

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Viewgraphs on controlled structures technology presented at the steering committee workshop on 22-23 Jan. 1992 are included. Topics addressed include: interferometer testbed; middeck 0-gravity dynamics experiment; middeck active control experiment; multivariable identification for control; strain actuated aeroelastic control; sensor/actuator technology development; input command shaping; and other research projects. A description of the organization and committee are included.

  2. Control augmentation for lateral control wheel steering

    NASA Technical Reports Server (NTRS)

    Foulkes, R. H., Jr.

    1981-01-01

    Flight control system design for lateral control wheel steering is discussed. Two alternate designs are presented. The first design is a roll-rate command, bank-angle hold system with a wings-level track-hold submode. The second is a curved-track-hold system. Design details and real-time flight simulator results are included.

  3. 46 CFR 115.814 - Steering systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Steering systems. 115.814 Section 115.814 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... capable of smooth operation by a single person in the manual mode, with hydraulic pumps secured....

  4. 46 CFR 115.814 - Steering systems.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Steering systems. 115.814 Section 115.814 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... capable of smooth operation by a single person in the manual mode, with hydraulic pumps secured....

  5. 46 CFR 115.814 - Steering systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Steering systems. 115.814 Section 115.814 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SMALL PASSENGER VESSELS CARRYING MORE THAN 150... capable of smooth operation by a single person in the manual mode, with hydraulic pumps secured....

  6. Agile manufacturing and constraints management: a strategic perspective

    NASA Astrophysics Data System (ADS)

    Stratton, Roy; Yusuf, Yahaya Y.

    2000-10-01

    The definition of the agile paradigm has proved elusive and is often viewed as a panacea, in contention with more traditional approaches to operations strategy development and Larkin its own methodology and tools. The Theory of Constraints (TOC) is also poorly understood, as it is commonly solely associated with production planning and control systems and bottleneck management. This paper will demonstrate the synergy between these two approaches together with the Theory of Inventive Problem Solving (TRIZ), and establish how the systematic elimination of trade-offs can support the agile paradigm. Whereas agility is often seen as a trade-off free destination, both TOC and TRIZ may be considered to be route finders, as they comprise methodologies that focus on the identification and elimination of the trade-offs that constrain the purposeful improvement of a system, be it organizational or mechanical. This paper will also show how the TOC thinking process may be combined with the TRIZ knowledge based approach and used in breaking contradictions within agile logistics.

  7. Network configuration management : paving the way to network agility.

    SciTech Connect

    Maestas, Joseph H.

    2007-08-01

    Sandia networks consist of nearly nine hundred routers and switches and nearly one million lines of command code, and each line ideally contributes to the capabilities of the network to convey information from one location to another. Sandia's Cyber Infrastructure Development and Deployment organizations recognize that it is therefore essential to standardize network configurations and enforce conformance to industry best business practices and documented internal configuration standards to provide a network that is agile, adaptable, and highly available. This is especially important in times of constrained budgets as members of the workforce are called upon to improve efficiency, effectiveness, and customer focus. Best business practices recommend using the standardized configurations in the enforcement process so that when root cause analysis results in recommended configuration changes, subsequent configuration auditing will improve compliance to the standard. Ultimately, this minimizes mean time to repair, maintains the network security posture, improves network availability, and enables efficient transition to new technologies. Network standardization brings improved network agility, which in turn enables enterprise agility, because the network touches all facets of corporate business. Improved network agility improves the business enterprise as a whole.

  8. Tailoring Agility: Promiscuous Pair Story Authoring and Value Calculation

    NASA Astrophysics Data System (ADS)

    Tendon, Steve

    This chapter describes how a multi-national software organization created a business plan involving business units from eight countries that followed an agile way, after two previously failed attempts with traditional approaches. The case is told by the consultant who initiated implementation of agility into requirements gathering, estimation and planning processes in an international setting. The agile approach was inspired by XP, but then tailored to meet the peculiar requirements. Two innovations were critical. The first innovation was promiscuous pair story authoring, where user stories were written by two people (similarly to pair programming), and the pairing changed very often (as frequently as every 15-20 minutes) to achieve promiscuity and cater for diverse point of views. The second innovation was an economic value evaluation (and not the cost) which was attributed to stories. Continuous recalculation of the financial value of the stories allowed to assess the projects financial return. In this case implementation of agility in the international context allowed the involved team members to reach consensus and unanimity of decisions, vision and purpose.

  9. Impact of Agile Software Development Model on Software Maintainability

    ERIC Educational Resources Information Center

    Gawali, Ajay R.

    2012-01-01

    Software maintenance and support costs account for up to 60% of the overall software life cycle cost and often burdens tightly budgeted information technology (IT) organizations. Agile software development approach delivers business value early, but implications on software maintainability are still unknown. The purpose of this quantitative study…

  10. Agile Software Development Methods: A Comparative Review1

    NASA Astrophysics Data System (ADS)

    Abrahamsson, Pekka; Oza, Nilay; Siponen, Mikko T.

    Although agile software development methods have caught the attention of software engineers and researchers worldwide, scientific research still remains quite scarce. The aim of this study is to order and make sense of the different agile approaches that have been proposed. This comparative review is performed from the standpoint of using the following features as the analytical perspectives: project management support, life-cycle coverage, type of practical guidance, adaptability in actual use, type of research objectives and existence of empirical evidence. The results show that agile software development methods cover, without offering any rationale, different phases of the software development life-cycle and that most of these methods fail to provide adequate project management support. Moreover, quite a few methods continue to offer little concrete guidance on how to use their solutions or how to adapt them in different development situations. Empirical evidence after ten years of application remains quite limited. Based on the results, new directions on agile methods are outlined.

  11. On the biomimetic design of agile-robot legs.

    PubMed

    Garcia, Elena; Arevalo, Juan Carlos; Muñoz, Gustavo; Gonzalez-de-Santos, Pablo

    2011-01-01

    The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented.

  12. A Capstone Course on Agile Software Development Using Scrum

    ERIC Educational Resources Information Center

    Mahnic, V.

    2012-01-01

    In this paper, an undergraduate capstone course in software engineering is described that not only exposes students to agile software development, but also makes it possible to observe the behavior of developers using Scrum for the first time. The course requires students to work as Scrum Teams, responsible for the implementation of a set of user…

  13. Current State of Agile User-Centered Design: A Survey

    NASA Astrophysics Data System (ADS)

    Hussain, Zahid; Slany, Wolfgang; Holzinger, Andreas

    Agile software development methods are quite popular nowadays and are being adopted at an increasing rate in the industry every year. However, these methods are still lacking usability awareness in their development lifecycle, and the integration of usability/User-Centered Design (UCD) into agile methods is not adequately addressed. This paper presents the preliminary results of a recently conducted online survey regarding the current state of the integration of agile methods and usability/UCD. A world wide response of 92 practitioners was received. The results show that the majority of practitioners perceive that the integration of agile methods with usability/UCD has added value to their adopted processes and to their teams; has resulted in the improvement of usability and quality of the product developed; and has increased the satisfaction of the end-users of the product developed. The top most used HCI techniques are low-fidelity prototyping, conceptual designs, observational studies of users, usability expert evaluations, field studies, personas, rapid iterative testing, and laboratory usability testing.

  14. On the Biomimetic Design of Agile-Robot Legs

    PubMed Central

    Garcia, Elena; Arevalo, Juan Carlos; Muñoz, Gustavo; Gonzalez-de-Santos, Pablo

    2011-01-01

    The development of functional legged robots has encountered its limits in human-made actuation technology. This paper describes research on the biomimetic design of legs for agile quadrupeds. A biomimetic leg concept that extracts key principles from horse legs which are responsible for the agile and powerful locomotion of these animals is presented. The proposed biomimetic leg model defines the effective leg length, leg kinematics, limb mass distribution, actuator power, and elastic energy recovery as determinants of agile locomotion, and values for these five key elements are given. The transfer of the extracted principles to technological instantiations is analyzed in detail, considering the availability of current materials, structures and actuators. A real leg prototype has been developed following the biomimetic leg concept proposed. The actuation system is based on the hybrid use of series elasticity and magneto-rheological dampers which provides variable compliance for natural motion. From the experimental evaluation of this prototype, conclusions on the current technological barriers to achieve real functional legged robots to walk dynamically in agile locomotion are presented. PMID:22247667

  15. Neuromuscular strategies contributing to faster multidirectional agility performance.

    PubMed

    Spiteri, Tania; Newton, Robert U; Nimphius, Sophia

    2015-08-01

    The aim of this study was to first determine differences in neuromuscular strategy between a faster and slower agility performance, and second compare differences in muscle activation strategy employed when performing two closely executed agility movements. Participants recruited from an elite female basketball team completed an ultrasound to determine quadriceps muscle-cross sectional area; reactive isometric mid-thigh pull to determine the rate of muscle activation, rate of force development, pre-motor time and motor time; and multidirectional agility tests completing two directional changes in response to a visual stimulus. Peak and average relative muscle activation of the rectus femoris, vastus medialis, vastus lateralis, biceps femoris, semitendinosus and gastrocnemius were measured 100ms prior to heel strike (pre-heel strike) and across stance phase for both directional changes. Faster agility performance was characterized by greater pre-heel strike muscle activity and greater anterior muscle activation during stance phase resulting in greater hip and knee extension increasing propulsive impulse. Differences between directional changes appear to result from processing speed, where a greater delay in refractory times during the second directional change resulted in greater anterior muscle activation, decelerating the body while movement direction was determined.

  16. Quadrupole Alignment and Trajectory Correction for Future Linear Colliders: SLC Tests of a Dispersion-Free Steering Algorithm

    SciTech Connect

    Assmann, R

    2004-06-08

    The feasibility of future linear colliders depends on achieving very tight alignment and steering tolerances. All proposals (NLC, JLC, CLIC, TESLA and S-BAND) currently require a total emittance growth in the main linac of less than 30-100% [1]. This should be compared with a 100% emittance growth in the much smaller SLC linac [2]. Major advances in alignment and beam steering techniques beyond those used in the SLC are necessary for the next generation of linear colliders. In this paper, we present an experimental study of quadrupole alignment with a dispersion-free steering algorithm. A closely related method (wakefield-free steering) takes into account wakefield effects [3]. However, this method can not be studied at the SLC. The requirements for future linear colliders lead to new and unconventional ideas about alignment and beam steering. For example, no dipole correctors are foreseen for the standard trajectory correction in the NLC [4]; beam steering will be done by moving the quadrupole positions with magnet movers. This illustrates the close symbiosis between alignment, beam steering and beam dynamics that will emerge. It is no longer possible to consider the accelerator alignment as static with only a few surveys and realignments per year. The alignment in future linear colliders will be a dynamic process in which the whole linac, with thousands of beam-line elements, is aligned in a few hours or minutes, while the required accuracy of about 5 pm for the NLC quadrupole alignment [4] is a factor of 20 higher than in existing accelerators. The major task in alignment and steering is the accurate determination of the optimum beam-line position. Ideally one would like all elements to be aligned along a straight line. However, this is not practical. Instead a ''smooth curve'' is acceptable as long as its wavelength is much longer than the betatron wavelength of the accelerated beam. Conventional alignment methods are limited in accuracy by errors in the survey

  17. Beam director design report: Volume 1

    SciTech Connect

    Younger, F.C.

    1986-08-01

    A design and fabrication effort for a beam director is documented. The conceptual design provides for the beam to pass first through a bending and focusing system (or ''achromat''), through a second achromat, through an air-to-vacuum interface (the ''beam window''), and finally through the vernier steering system. Following an initial concept study for a beam director, a prototype permanent magnet 30/sup 0/ beam-bending achromat and a prototype vernier steering magnet were designed and built. In volume I, the design requirements are stated, the design is summarized and illustrated, and detailed analysis and computations are provided. Also, a summary of materials used, a description of the manufacturing process, and a summary of project funding are provided. (LEW)

  18. AGILE integration into APC for high mix logic fab

    NASA Astrophysics Data System (ADS)

    Gatefait, M.; Lam, A.; Le Gratiet, B.; Mikolajczak, M.; Morin, V.; Chojnowski, N.; Kocsis, Z.; Smith, I.; Decaunes, J.; Ostrovsky, A.; Monget, C.

    2015-09-01

    For C040 technology and below, photolithographic depth of focus control and dispersion improvement is essential to secure product functionality. Critical 193nm immersion layers present initial focus process windows close to machine control capability. For previous technologies, the standard scanner sensor (Level sensor - LS) was used to map wafer topology and expose the wafer at the right Focus. Such optical embedded metrology, based on light reflection, suffers from reading issues that cannot be neglected anymore. Metrology errors are correlated to inspected product area for which material types and densities change, and so optical properties are not constant. Various optical phenomena occur across the product field during wafer inspection and have an effect on the quality and position of the reflected light. This can result in incorrect heights being recorded and exposures possibly being done out of focus. Focus inaccuracy associated to aggressive process windows on critical layers will directly impact product realization and therefore functionality and yield. ASML has introduced an air gauge sensor to complement the optical level sensor and lead to optimal topology metrology. The use of this new sensor is managed by the AGILE (Air Gauge Improved process LEveling) application. This measurement with no optical dependency will correct for optical inaccuracy of level sensor, and so improve best focus dispersion across the product. Due to the fact that stack complexity is more and more important through process steps flow, optical perturbation of standard Level sensor metrology is increasing and is becoming maximum for metallization layers. For these reasons AGILE feature implementation was first considered for contact and all metal layers. Another key point is that standard metrology will be sensitive to layer and reticle/product density. The gain of Agile will be enhanced for multiple product contribution mask and for complex System on Chip. Into ST context (High

  19. Using Stars to Align a Steered Laser System for Cosmic Ray Simulation

    NASA Astrophysics Data System (ADS)

    Krantz, Harry; Wiencke, Lawrence

    2016-03-01

    Ultra high energy cosmic rays (UHECRs) are the highest energy cosmic particles with kinetic energy above 1018eV . UHECRs are detected from the air shower of secondary particles and UV florescence that results from interaction with the atmosphere. A high power UV laser beam can be used to simulate the optical signature of a UHCER air shower. The Global Light System (GLS) is a planned network of ground-based light sources including lasers to support the planned space-based Extreme Universe Space Observatory (EUSO). A portable prototype GLS laser station has been constructed at the Colorado School of Mines. Currently the laser system uses reference targets on the ground but stars can be used to better align the beam by providing a complete hemisphere of targets. In this work, a CCD camera is used to capture images of known stars through the steering head optics. The images are analyzed to find the steering head coordinates of the target star. The true coordinates of the star are calculated from the location and time of observation. A universal adjustment for the steering head is determined from the differences between the two pairs of coordinates across multiple stars. This laser system prototype will also be used for preflight tests of the ESUO Super Pressure Balloon mission.

  20. The effect of acute stretching on agility performance.

    PubMed

    Van Gelder, Leonard H; Bartz, Shari D

    2011-11-01

    Static stretching (SS) has shown decreases in many areas including strength, anaerobic power, and sprinting time. Dynamic stretching (DS) has shown increases in anaerobic power and decreases in sprinting time. Research on the effects of stretching on agility performance is limited. The purpose of this study was to determine the effect of SS and DS on performance time of a sport agility test. Sixty male subjects consisting of collegiate (n = 18) and recreational (n = 42) basketball athletes volunteered for the study. Subjects were randomly assigned to 1 of 3 intervention groups: SS, DS, or no stretching (NS). All groups completed a 10-minute warm-up jog followed by a 3-minute rest. The SS and DS groups then completed an 8.5-minute stretching intervention. Next, all subjects completed 3 trials of the 505 agility test with 2-5 minutes of rest between trials. A 2-way repeated-measure analysis of variance (Stretch group, athlete category, group × athlete interaction) was used to determine statistical significance (p < 0.05). A Tukey post hoc test was performed to determine differences between groups. For all athletes, the DS group produced significantly faster times on the agility test (2.22 ± 0.12 seconds, mean ± SD) in comparison to both the SS group (2.33 ± 0.15 seconds, p = 0.013) and NS group (2.32 ± 0.12 seconds, p = 0.026). Differences between the SS and NS groups revealed no significance (p = 0.962). There was a significant difference in mean times for the type of athlete (p = 0.002); however, interaction between the type of athlete and stretching group was not significant (p = 0.520). These results indicate that in comparison to SS or NS, DS significantly improves performance on closed agility skills involving a 180° change of direction.

  1. Agility Meets Systems Engineering: A Catalogue of Success Factors from Industry Practice

    NASA Astrophysics Data System (ADS)

    Stelzmann, Ernst; Kreiner, Christian; Spork, Gunther; Messnarz, Richard; Koenig, Frank

    Agile software development methods are widely accepted and valued in software-dominated industries. In more complex setups like multidisciplinary system development the adoption of an agile development paradigm is much less straightforward. Bigger teams, longer development cycles, process and product standard compliance and products lacking flexibility make an agile behaviour more difficult to achieve. Focusing on the fundamental underlying problem of dealing with ever ongoing change, this paper presents an agile Systems Engineering approach as a potential solution. Therefore a generic Systems Engineering action model was upgraded respecting agile principles and adapted according to practical needs discovered in an empirical study. This study was conducted among the partners of the S2QI agile workgroup made up from experts of automotive, logistics and electronics industries. Additionally to an agile Systems Engineering action model, a list of 15 practical success factors that should be considered when using an agile Systems Engineering approach is one of the main outcomes of this survey. It was also found that an agile behaviour in Systems Engineering could be supported in many different areas within companies. These areas are listed and it is also shown how the agile action model and the agile success factors are related to them.

  2. Transverse centroid oscillations in solenoidially focused beam transport lattices

    SciTech Connect

    Lund, Steven M.; Wootton, Christopher J.; Lee, Edward P.

    2008-08-01

    Linear equations of motion are derived that describe small-amplitude centroid oscillations induced by displacement and rotational misalignments of the focusing solenoids in the transport lattice, dipole steering elements, and initial centroid offset errors. These equations are analyzed in a local rotating Larmor frame to derive complex-variable"alignment functions" and"bending functions" that efficiently describe the characteristics of the centroid oscillations induced by mechanical misalignments of the solenoids and dipole steering elements. The alignment and bending functions depend only on properties of the ideal lattice in the absence of errors and steering and have associated expansion amplitudes set by the misalignments and steering fields. Applications of this formulation are presented for statistical analysis of centroid deviations, calculation of actual lattice misalignments from centroid measurements, and optimal beam steering.

  3. Transverse Centroid Oscillations in Solenoidially Focused Beam Transport Lattices

    SciTech Connect

    Lund, S M; Wootton, C J; Lee, E P

    2008-08-01

    Linear equations of motion are derived that describe small-amplitude centroid oscillations induced by displacement and rotational misalignments of the focusing solenoids in the transport lattice, dipole steering elements, and initial centroid offset errors. These equations are analyzed in a local rotating Larmor frame to derive complex-variable 'alignment functions' and 'bending functions' that efficiently describe the characteristics of the centroid oscillations induced by mechanical misalignments of the solenoids and dipole steering elements. The alignment and bending functions depend only on properties of the ideal lattice in the absence of errors and steering and have associated expansion amplitudes set by the misalignments and steering fields. Applications of this formulation are presented for statistical analysis of centroid deviations, calculation of actual lattice misalignments from centroid measurements, and optimal beam steering.

  4. Method of Controlling Steering of a Ground Vehicle

    NASA Technical Reports Server (NTRS)

    Dawson, Andrew D. (Inventor); Bluethmann, William J. (Inventor); Lee, Chunhao J. (Inventor); Vitale, Robert L. (Inventor); Guo, Raymond (Inventor); Atluri, Venkata Prasad (Inventor)

    2016-01-01

    A method of controlling steering of a vehicle through setting wheel angles of a plurality of modular electronic corner assemblies (eModules) is provided. The method includes receiving a driving mode selected from a mode selection menu. A position of a steering input device is determined in a master controller. A velocity of the vehicle is determined, in the master controller, when the determined position of the steering input device is near center. A drive mode request corresponding to the selected driving mode to the plurality of steering controllers is transmitted to the master controller. A required steering angle of each of the plurality of eModules is determined, in the master controller, as a function of the determined position of the steering input device, the determined velocity of the vehicle, and the selected first driving mode. The eModules are set to the respective determined steering angles.

  5. Steering system for a train of rail-less vehicles

    DOEpatents

    Voight, Edward T.

    1983-01-01

    A steering system for use with a multiple vehicle train permits tracking without rails of one vehicle after another. This system is particularly useful for moving conveyor systems into and out of curved paths of room and pillar underground mine installations. The steering system features an elongated steering bar pivotally connected to each of adjacent vehicles at end portions of the bar permitting angular orientation of each vehicle in respect to the steering bar and other vehicles. Each end portion of the steering bar is linked to the near pair of vehicle wheels through wheel yoke pivot arms about king pin type pivots. Movement of the steering bar about its pivotal connection provides proportional turning of the wheels to effect steering and tracking of one vehicle following another in both forward and reverse directions.

  6. Beam-Forming Concentrating Solar Thermal Array Power Systems

    NASA Technical Reports Server (NTRS)

    Cwik, Thomas A. (Inventor); Dimotakis, Paul E. (Inventor); Hoppe, Daniel J. (Inventor)

    2016-01-01

    The present invention relates to concentrating solar-power systems and, more particularly, beam-forming concentrating solar thermal array power systems. A solar thermal array power system is provided, including a plurality of solar concentrators arranged in pods. Each solar concentrator includes a solar collector, one or more beam-forming elements, and one or more beam-steering elements. The solar collector is dimensioned to collect and divert incoming rays of sunlight. The beam-forming elements intercept the diverted rays of sunlight, and are shaped to concentrate the rays of sunlight into a beam. The steering elements are shaped, dimensioned, positioned, and/or oriented to deflect the beam toward a beam output path. The beams from the concentrators are converted to heat at a receiver, and the heat may be temporarily stored or directly used to generate electricity.

  7. Nonlinear optical protection against frequency agile lasers

    SciTech Connect

    McDowell, V.P.

    1988-08-04

    An eye-protection or equipment-filter device for protection from laser energy is disclosed. The device may be in the form of a telescope, binoculars, goggles, constructed as part of equipment such as image intensifiers or range designators. Optical elements focus the waist of the beam within a nonlinear frequency-doubling crystal or nonlinear optical element or fiber. The nonlinear elements produce a harmonic outside the visible spectrum in the case of crystals, or absorb the laser energy in the case of nonlinear fibers. Embodiments include protectors for the human eye as well as filters for sensitive machinery such as TV cameras, FLIR systems or other imaging equipment.

  8. Organizational Agility and Complex Enterprise System Innovations: A Mixed Methods Study of the Effects of Enterprise Systems on Organizational Agility

    ERIC Educational Resources Information Center

    Kharabe, Amol T.

    2012-01-01

    Over the last two decades, firms have operated in "increasingly" accelerated "high-velocity" dynamic markets, which require them to become "agile." During the same time frame, firms have increasingly deployed complex enterprise systems--large-scale packaged software "innovations" that integrate and automate…

  9. Stabilization and steering of a parabolic laser thermal thruster with an ignition device

    NASA Astrophysics Data System (ADS)

    Scharring, Stefan; Hoffmann, Daniela; Eckel, Hans-Albert; Röser, Hans-Peter

    2009-12-01

    High energy pulses of a CO 2 laser are focused in a parabolic mirror yielding to a laser-supported detonation. The generated thrust acting on the reflector as a bell nozzle is studied in multiple pulse free flight experiments with respect to axial, lateral and angular momentum coupling. The employment of an ignition pin on the reflector's axis of symmetry lowering the ignition threshold by several orders of magnitude is found to provide for a reproducible detonation process. The axial momentum coupling of each pulse is analyzed with respect to initial lateral offset and tilt during the flight. High speed analyses of recorded flights indicate that lateral momentum components occur re-centering the thruster on the beam. Thrust vector steering can be realized by tilt of the ignition pin inside the thruster, thus shifting the detonation. A design model of a laser-driven rocket including a remotely accessible steering gear was developed and tested successfully.

  10. Beam based alignment of sector-1 of the SLC linac

    SciTech Connect

    Emma, P.

    1992-03-01

    A technique is described which uses the beam to simultaneously measure quadrupole magnet and beam position monitor (BPM) transverse misalignments. The technique is applied to sector-1 of the SLC linac where simultaneous acceleration of electron and positron beams with minimal steering elements and BPMs makes quadrupole alignment critical for high transmission of the large transverse emittance positron beam. Simulation results as well as measurements are presented.

  11. A steering mechanism for phototaxis in Chlamydomonas

    NASA Astrophysics Data System (ADS)

    Bennett, Rachel; Golestanian, Ramin

    2015-03-01

    Chlamydomonas shows both positive and negative phototaxis. It has a single eyespot near its equator and as the cell rotates during forward motion the light signal received by the eyespot varies. We use a simple mechanical model of Chlamydomonas that couples the flagellar beat pattern to the light intensity at the eyespot to demonstrate a mechanism for phototactic steering that is consistent with observations. The direction of phototaxis is controlled by a parameter in our model and the steering mechanism is robust to noise. In the dark, our model shows emergent run-and-tumble behavior and we see switching between directed phototaxis and run-and-tumble when we switch the light on and off.

  12. Boundaries can steer active Janus spheres

    PubMed Central

    Das, Sambeeta; Garg, Astha; Campbell, Andrew I.; Howse, Jonathan; Sen, Ayusman; Velegol, Darrell; Golestanian, Ramin; Ebbens, Stephen J.

    2015-01-01

    The advent of autonomous self-propulsion has instigated research towards making colloidal machines that can deliver mechanical work in the form of transport, and other functions such as sensing and cleaning. While much progress has been made in the last 10 years on various mechanisms to generate self-propulsion, the ability to steer self-propelled colloidal devices has so far been much more limited. A critical barrier in increasing the impact of such motors is in directing their motion against the Brownian rotation, which randomizes particle orientations. In this context, here we report directed motion of a specific class of catalytic motors when moving in close proximity to solid surfaces. This is achieved through active quenching of their Brownian rotation by constraining it in a rotational well, caused not by equilibrium, but by hydrodynamic effects. We demonstrate how combining these geometric constraints can be utilized to steer these active colloids along arbitrary trajectories. PMID:26627125

  13. Boundaries can steer active Janus spheres

    NASA Astrophysics Data System (ADS)

    Das, Sambeeta; Garg, Astha; Campbell, Andrew I.; Howse, Jonathan; Sen, Ayusman; Velegol, Darrell; Golestanian, Ramin; Ebbens, Stephen J.

    2015-12-01

    The advent of autonomous self-propulsion has instigated research towards making colloidal machines that can deliver mechanical work in the form of transport, and other functions such as sensing and cleaning. While much progress has been made in the last 10 years on various mechanisms to generate self-propulsion, the ability to steer self-propelled colloidal devices has so far been much more limited. A critical barrier in increasing the impact of such motors is in directing their motion against the Brownian rotation, which randomizes particle orientations. In this context, here we report directed motion of a specific class of catalytic motors when moving in close proximity to solid surfaces. This is achieved through active quenching of their Brownian rotation by constraining it in a rotational well, caused not by equilibrium, but by hydrodynamic effects. We demonstrate how combining these geometric constraints can be utilized to steer these active colloids along arbitrary trajectories.

  14. Pointing Device Performance in Steering Tasks.

    PubMed

    Senanayake, Ransalu; Goonetilleke, Ravindra S

    2016-06-01

    Use of touch-screen-based interactions is growing rapidly. Hence, knowing the maneuvering efficacy of touch screens relative to other pointing devices is of great importance in the context of graphical user interfaces. Movement time, accuracy, and user preferences of four pointing device settings were evaluated on a computer with 14 participants aged 20.1 ± 3.13 years. It was found that, depending on the difficulty of the task, the optimal settings differ for ballistic and visual control tasks. With a touch screen, resting the arm increased movement time for steering tasks. When both performance and comfort are considered, whether to use a mouse or a touch screen for person-computer interaction depends on the steering difficulty. Hence, a input device should be chosen based on the application, and should be optimized to match the graphical user interface. PMID:27216944

  15. Influence of steering effects on strain detection in AlGaInN/GaN heterostructures by ion channelling

    NASA Astrophysics Data System (ADS)

    Redondo-Cubero, A.; Lorenz, K.; Franco, N.; Fernández-Garrido, S.; Gago, R.; Smulders, P. J. M.; Muñoz, E.; Calleja, E.; Alves, E.

    2009-03-01

    Ion steering effects in the interface of heterostructures can strongly influence the shape and position of angular channelling scans leading to considerable error in the determination of strain by ion channelling. As an example, this paper presents channelling measurements on a near-lattice-matched AlGaInN/GaN heterostructure which show no shift between the angular scans from the quaternary layer and the underlying GaN substrate although high resolution x-ray diffraction data confirm the presence of strain in the layer. Such 'anomalous' behaviour was studied by means of Monte Carlo simulations for nitride ternary and quaternary films in the whole composition range. The simulations show that the thickness, magnitude of the distortion of the strained lattice and energy of the probing beam are critical parameters controlling the impact of steering. Three composition/strain regions were established for a typical beam of 2 MeV alpha particles corresponding to different intensities of the steering potential and in which strain measurements by ion channelling are (a) correct, (b) possible but require corrections and (c) not possible due to steering effects.

  16. Self-testing through EPR-steering

    NASA Astrophysics Data System (ADS)

    Šupić, Ivan; Hoban, Matty J.

    2016-07-01

    The verification of quantum devices is an important aspect of quantum information, especially with the emergence of more advanced experimental implementations of quantum computation and secure communication. Within this, the theory of device-independent robust self-testing via Bell tests has reached a level of maturity now that many quantum states and measurements can be verified without direct access to the quantum systems: interaction with the devices is solely classical. However, the requirements for this robust level of verification are daunting and require high levels of experimental accuracy. In this paper we discuss the possibility of self-testing where we only have direct access to one part of the quantum device. This motivates the study of self-testing via EPR-steering, an intermediate form of entanglement verification between full state tomography and Bell tests. Quantum non-locality implies EPR-steering so results in the former can apply in the latter, but we ask what advantages may be gleaned from the latter over the former given that one can do partial state tomography? We show that in the case of self-testing a maximally entangled two-qubit state, or ebit, EPR-steering allows for simpler analysis and better error tolerance than in the case of full device-independence. On the other hand, this improvement is only a constant improvement and (up to constants) is the best one can hope for. Finally, we indicate that the main advantage in self-testing based on EPR-steering could be in the case of self-testing multi-partite quantum states and measurements. For example, it may be easier to establish a tensor product structure for a particular party’s Hilbert space even if we do not have access to their part of the global quantum system.

  17. Vertical flight path steering system for aircraft

    NASA Technical Reports Server (NTRS)

    Lambregts, Antonius A. (Inventor)

    1983-01-01

    Disclosed is a vertical flight path angle steering system for aircraft, utilizing a digital flight control computer which processes pilot control inputs and aircraft response parameters into suitable elevator commands and control information for display to the pilot on a cathode ray tube. The system yields desirable airplane control handling qualities and responses as well as improvements in pilot workload and safety during airplane operation in the terminal area and under windshear conditions.

  18. On the Feasibility of Dynamic Power Steering

    SciTech Connect

    Barker, Kevin J.; Kerbyson, Darren J.; Anger, Eric A.

    2014-11-16

    While high performance has always been the primary constraint behind large-scale system design, future systems will be built with increasing energy efficiency in mind. Mechanisms such as fine-grained power scaling and gating will provide tools to system-software and application developers to ensure the most efficient use of tightly constrained power budgets. Such approaches to-date have been focused on node level optimizations to impact overall system energy efficiency. In this work we introduce Dynamic Power Steering, in which power can be dynamically routed across a system to resources where it will be of most benefit and away from other resources to maintain a near-constant overall power budget. This, a higher level algorithmic approach to improving energy efficiency, considers the whole extent of a system being used by an application. It can be used for applications in which there is load imbalance that varies over its execution. Using two classes of applications, namely those that contain a wave front type processing, and a particle-in-cell, we quantify the benefit of Dynamic Power Steering for a variety of workload characteristics and derive some insight into the ways in which workload behavior affect Power Steering applicability.

  19. Preparing your Offshore Organization for Agility: Experiences in India

    NASA Astrophysics Data System (ADS)

    Srinivasan, Jayakanth

    Two strategies that have significantly changed the way we conventionally think about managing software development and sustainment are the family of development approaches collectively referred to as agile methods, and the distribution of development efforts on a global scale. When you combine the two strategies, organizations have to address not only the technical challenges that arise from introducing new ways of working, but more importantly have to manage the 'soft' factors that if ignored lead to hard challenges. Using two case studies of distributed agile software development in India we illustrate the areas that organizations need to be aware of when transitioning work to India. The key issues that we emphasize are the need to recruit and retain personnel; the importance of teaching, mentoring and coaching; the need to manage customer expectations; the criticality of well-articulated senior leadership vision and commitment; and the reality of operating in a heterogeneous process environment.

  20. Agile Data Management with the Global Change Information System

    NASA Astrophysics Data System (ADS)

    Duggan, B.; Aulenbach, S.; Tilmes, C.; Goldstein, J.

    2013-12-01

    We describe experiences applying agile software development techniques to the realm of data management during the development of the Global Change Information System (GCIS), a web service and API for authoritative global change information under development by the US Global Change Research Program. Some of the challenges during system design and implementation have been : (1) balancing the need for a rigorous mechanism for ensuring information quality with the realities of large data sets whose contents are often in flux, (2) utilizing existing data to inform decisions about the scope and nature of new data, and (3) continuously incorporating new knowledge and concepts into a relational data model. The workflow for managing the content of the system has much in common with the development of the system itself. We examine various aspects of agile software development and discuss whether or how we have been able to use them for data curation as well as software development.

  1. Sprint, agility, strength and endurance capacity in wheelchair basketball players

    PubMed Central

    Granados, C; Otero, M; Badiola, A; Olasagasti, J; Bidaurrazaga-Letona, I; Iturricastillo, A; Gil, SM

    2014-01-01

    The aims of the present study were, firstly, to determine the reliability and reproducibility of an agility T-test and Yo-Yo 10 m recovery test; and secondly, to analyse the physical characteristics measured by sprint, agility, strength and endurance field tests in wheelchair basketball (WB) players. 16 WB players (33.06 ± 7.36 years, 71.89 ± 21.71 kg and sitting body height 86.07 ± 6.82 cm) belonging to the national WB league participated in this study. Wheelchair sprint (5 and 20 m without ball, and 5 and 20 m with ball) agility (T-test and pick-up test) strength (handgrip and maximal pass) and endurance (Yo-Yo 10 m recovery test) were performed. T-test and Yo-Yo 10 m recovery test showed good reproducibility values (intraclass correlation coefficient, ICC = 0.74-0.94). The WB players’ results in 5 and 20 m sprints without a ball were 1.87 ± 0.21 s and 5.70 ± 0.43 s and with a ball 2.10 ± 0.30 s and 6.59 ± 0.61 s, being better than those reported in the literature. Regarding the pick-up test results (16.05 ± 0.52 s) and maximal pass (8.39 ± 1.77 m), players showed worse values than those obtained in elite players. The main contribution of the present study is the characterization of the physical performance profile of WB players using a field test battery. Furthermore, we demonstrated that the agility T-test and the aerobic Yo-Yo 10 m recovery test are reliable; consequently they may be appropriate instruments for measuring physical fitness in WB. PMID:25729153

  2. Sprint, agility, strength and endurance capacity in wheelchair basketball players.

    PubMed

    Yanci, J; Granados, C; Otero, M; Badiola, A; Olasagasti, J; Bidaurrazaga-Letona, I; Iturricastillo, A; Gil, Sm

    2015-03-01

    The aims of the present study were, firstly, to determine the reliability and reproducibility of an agility T-test and Yo-Yo 10 m recovery test; and secondly, to analyse the physical characteristics measured by sprint, agility, strength and endurance field tests in wheelchair basketball (WB) players. 16 WB players (33.06 ± 7.36 years, 71.89 ± 21.71 kg and sitting body height 86.07 ± 6.82 cm) belonging to the national WB league participated in this study. Wheelchair sprint (5 and 20 m without ball, and 5 and 20 m with ball) agility (T-test and pick-up test) strength (handgrip and maximal pass) and endurance (Yo-Yo 10 m recovery test) were performed. T-test and Yo-Yo 10 m recovery test showed good reproducibility values (intraclass correlation coefficient, ICC = 0.74-0.94). The WB players' results in 5 and 20 m sprints without a ball were 1.87 ± 0.21 s and 5.70 ± 0.43 s and with a ball 2.10 ± 0.30 s and 6.59 ± 0.61 s, being better than those reported in the literature. Regarding the pick-up test results (16.05 ± 0.52 s) and maximal pass (8.39 ± 1.77 m), players showed worse values than those obtained in elite players. The main contribution of the present study is the characterization of the physical performance profile of WB players using a field test battery. Furthermore, we demonstrated that the agility T-test and the aerobic Yo-Yo 10 m recovery test are reliable; consequently they may be appropriate instruments for measuring physical fitness in WB. PMID:25729153

  3. Measuring The Variability Of Gamma-Ray Sources With AGILE

    SciTech Connect

    Chen, Andrew W.; Vercellone, Stefano; Pellizzoni, Alberto; Tavani, Marco

    2005-02-21

    Variability in the gamma-ray flux above 100 MeV at various time scales is one of the primary characteristics of the sources detected by EGRET, both allowing the identification of individual sources and constraining the unidentified source classes. We present a detailed simulation of the capacity of AGILE to characterize the variability of gamma-ray sources, discussing the implications for source population studies.

  4. AGILE Observations of the Gravitational-wave Event GW150914

    NASA Astrophysics Data System (ADS)

    Tavani, M.; Pittori, C.; Verrecchia, F.; Bulgarelli, A.; Giuliani, A.; Donnarumma, I.; Argan, A.; Trois, A.; Lucarelli, F.; Marisaldi, M.; Del Monte, E.; Evangelista, Y.; Fioretti, V.; Zoli, A.; Piano, G.; Munar-Adrover, P.; Antonelli, L. A.; Barbiellini, G.; Caraveo, P.; Cattaneo, P. W.; Costa, E.; Feroci, M.; Ferrari, A.; Longo, F.; Mereghetti, S.; Minervini, G.; Morselli, A.; Pacciani, L.; Pellizzoni, A.; Picozza, P.; Pilia, M.; Rappoldi, A.; Sabatini, S.; Vercellone, S.; Vittorini, V.; Giommi, P.; Colafrancesco, S.; Cardillo, M.; Galli, M.; Fuschino, F.

    2016-07-01

    We report the results of an extensive search through the AGILE data for a gamma-ray counterpart to the LIGO gravitational-wave (GW) event GW150914. Currently in spinning mode, AGILE has the potential of cover 80% of the sky with its gamma-ray instrument, more than 100 times a day. It turns out that AGILE came within a minute of the event time of observing the accessible GW150914 localization region. Interestingly, the gamma-ray detector exposed ∼65% of this region during the 100 s time intervals centered at ‑100 and +300 s from the event time. We determine a 2σ flux upper limit in the band 50 MeV–10 GeV, UL = 1.9 × 10‑8 erg cm‑2 s‑1, obtained ∼300 s after the event. The timing of this measurement is the fastest ever obtained for GW150914, and significantly constrains the electromagnetic emission of a possible high-energy counterpart. We also carried out a search for a gamma-ray precursor and delayed emission over five timescales ranging from minutes to days: in particular, we obtained an optimal exposure during the interval ‑150/‑30 s. In all these observations, we do not detect a significant signal associated with GW150914. We do not reveal the weak transient source reported by Fermi-GBM 0.4 s after the event time. However, even though a gamma-ray counterpart of the GW150914 event was not detected, the prospects for future AGILE observations of GW sources are decidedly promising.

  5. Sprint, agility, strength and endurance capacity in wheelchair basketball players.

    PubMed

    Yanci, J; Granados, C; Otero, M; Badiola, A; Olasagasti, J; Bidaurrazaga-Letona, I; Iturricastillo, A; Gil, Sm

    2015-03-01

    The aims of the present study were, firstly, to determine the reliability and reproducibility of an agility T-test and Yo-Yo 10 m recovery test; and secondly, to analyse the physical characteristics measured by sprint, agility, strength and endurance field tests in wheelchair basketball (WB) players. 16 WB players (33.06 ± 7.36 years, 71.89 ± 21.71 kg and sitting body height 86.07 ± 6.82 cm) belonging to the national WB league participated in this study. Wheelchair sprint (5 and 20 m without ball, and 5 and 20 m with ball) agility (T-test and pick-up test) strength (handgrip and maximal pass) and endurance (Yo-Yo 10 m recovery test) were performed. T-test and Yo-Yo 10 m recovery test showed good reproducibility values (intraclass correlation coefficient, ICC = 0.74-0.94). The WB players' results in 5 and 20 m sprints without a ball were 1.87 ± 0.21 s and 5.70 ± 0.43 s and with a ball 2.10 ± 0.30 s and 6.59 ± 0.61 s, being better than those reported in the literature. Regarding the pick-up test results (16.05 ± 0.52 s) and maximal pass (8.39 ± 1.77 m), players showed worse values than those obtained in elite players. The main contribution of the present study is the characterization of the physical performance profile of WB players using a field test battery. Furthermore, we demonstrated that the agility T-test and the aerobic Yo-Yo 10 m recovery test are reliable; consequently they may be appropriate instruments for measuring physical fitness in WB.

  6. Steering and Suspension Systems. Auto Mechanics Curriculum Guide. Module 5. Instructor's Guide.

    ERIC Educational Resources Information Center

    Rains, Larry

    This module is the fifth of nine modules in the competency-based Missouri Auto Mechanics Curriculum Guide. Seventeen units cover: steering system design; diagnosing steering systems problems; inspecting and replacing steering linkage components; manual and power steering gear service; manual and power rack and pinion steering gear service; power…

  7. 78 FR 15062 - Cohen & Steers Real Assets Fund, Inc., et al.; Notice of Application

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-03-08

    ... COMMISSION Cohen & Steers Real Assets Fund, Inc., et al.; Notice of Application March 4, 2013. AGENCY...: Cohen & Steers Real Assets Fund, Inc. (the ``Corporation''), Cohen & Steers Real Assets Fund, Ltd. (the ``Subsidiary''), and Cohen & Steers Capital Management, Inc. (``Cohen & Steers'' or the ``Advisor'')....

  8. 46 CFR 58.25-80 - Automatic pilots and ancillary steering gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... AND AUXILIARY MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-80 Automatic pilots and ancillary steering gear. (a) Automatic pilots and ancillary steering gear, and steering-gear control systems, must be arranged to allow immediate resumption of manual operation of the steering-gear control system required...

  9. SAR imagery using chaotic carrier frequency agility pulses

    NASA Astrophysics Data System (ADS)

    Xu, Xiaojian; Feng, Xiangzhi

    2011-06-01

    Synthetic aperture radar (SAR) systems are getting more and more applications in both civilian and military remote sensing missions. With the increasing deployment of electronic countermeasures (ECM) on modern battlefields, SAR encounters more and more interference jamming signals. The ECM jamming signals cause the SAR system to receive and process erroneous information which results in severe degradations in the output SAR images and/or formation of phony images of nonexistent targets. As a consequence, development of the electronic counter-countermeasures (ECCM) capability becomes one of the key problems in SAR system design. This paper develops radar signaling strategies and algorithms that enhance the ability of synthetic aperture radar to image targets under conditions of electronic jamming. The concept of SAR using chaotic carrier frequency agility pulses (CCFAP-SAR) is first proposed. Then the imaging procedure for CCFAP-SAR is discussed in detail. The ECCM performance of CCFAP-SAR for both depressive noise jamming and deceptive repeat jamming is analyzed. The impact of the carrier frequency agility range on the image quality of CCFAP-SAR is also studied. Simulation results demonstrate that, with adequate agility range of the carrier frequency, the proposed CCFAP-SAR performs as well as conventional radar with linear frequency modulation (LFM) waveform in image quality and slightly better in anti-noise depressive jamming; while performs very well in anti-deception jamming which cannot be rejected by LFM-SAR.

  10. Integrating a distributed, agile, virtual enterprise in the TEAM program

    NASA Astrophysics Data System (ADS)

    Cobb, C. K.; Gray, W. Harvey; Hewgley, Robert E.; Klages, Edward J.; Neal, Richard E.

    1997-01-01

    The technologies enabling agile manufacturing (TEAM) program enhances industrial capability by advancing and deploying manufacturing technologies that promote agility. TEAM has developed a product realization process that features the integration of product design and manufacturing groups. TEAM uses the tools it collects, develops, and integrates in support of the product realization process to demonstrate and deploy agile manufacturing capabilities for three high- priority processes identified by industry: material removal, forming, and electromechanical assembly. In order to provide a proof-of-principle, the material removal process has been addressed first and has been successfully demonstrate din an 'interconnected' mode. An internet-accessible intersite file manager (IFM) application has been deployed to allow geographically distributed TEAM participants to share and distribute information as the product realization process is executed. An automated inspection planning application has been demonstrated, importing a solid model form the IFM, generating an inspection plan and a part program to be used in the inspection process, and then distributing the part program to the inspection site via the IFM. TEAM seeks to demonstrate the material removal process in an integrated mode in June 1997 complete with an object-oriented framework and infrastructure. The current status and future plans for this project are presented here.

  11. Clustering-based urbanisation to improve enterprise information systems agility

    NASA Astrophysics Data System (ADS)

    Imache, Rabah; Izza, Said; Ahmed-Nacer, Mohamed

    2015-11-01

    Enterprises are daily facing pressures to demonstrate their ability to adapt quickly to the unpredictable changes of their dynamic in terms of technology, social, legislative, competitiveness and globalisation. Thus, to ensure its place in this hard context, enterprise must always be agile and must ensure its sustainability by a continuous improvement of its information system (IS). Therefore, the agility of enterprise information systems (EISs) can be considered today as a primary objective of any enterprise. One way of achieving this objective is by the urbanisation of the EIS in the context of continuous improvement to make it a real asset servicing enterprise strategy. This paper investigates the benefits of EISs urbanisation based on clustering techniques as a driver for agility production and/or improvement to help managers and IT management departments to improve continuously the performance of the enterprise and make appropriate decisions in the scope of the enterprise objectives and strategy. This approach is applied to the urbanisation of a tour operator EIS.

  12. Agile Science Operations: A New Approach for Primitive Exploration Bodies

    NASA Technical Reports Server (NTRS)

    Chien, Steve A.; Thompson, David R.; Castillo-Rogez, Julie C.; Doyle, Richard; Estlin, Tara; Mclaren, David

    2012-01-01

    Primitive body exploration missions such as potential Comet Surface Sample Return or Trojan Tour and Rendezvous would challenge traditional operations practices. Earth-based observations would provide only basic understanding before arrival and many science goals would be defined during the initial rendezvous. It could be necessary to revise trajectories and observation plans to quickly characterize the target for safe, effective observations. Detection of outgassing activity and monitoring of comet surface activity are even more time constrained, with events occurring faster than round-trip light time. "Agile science operations" address these challenges with contingency plans that recognize the intrinsic uncertainty in the operating environment and science objectives. Planning for multiple alternatives can significantly improve the time required to repair and validate spacecraft command sequences. When appropriate, time-critical decisions can be automated and shifted to the spacecraft for immediate access to instrument data. Mirrored planning systems on both sides of the light-time gap permit transfer of authority back and forth as needed. We survey relevant science objectives, identifying time bottlenecks and the techniques that could be used to speed missions' reaction to new science data. Finally, we discuss the results of a trade study simulating agile observations during flyby and comet rendezvous scenarios. These experiments quantify instrument coverage of key surface features as a function of planning turnaround time. Careful application of agile operations techniques can play a significant role in realizing the Decadal Survey plan for primitive body exploration

  13. Agile Data Curation at a State Geological Survey

    NASA Astrophysics Data System (ADS)

    Hills, D. J.

    2015-12-01

    State agencies, including geological surveys, are often the gatekeepers for myriad data products essential for scientific research and economic development. For example, the Geological Survey of Alabama (GSA) is mandated to explore for, characterize, and report Alabama's mineral, energy, water, and biological resources in support of economic development, conservation, management, and public policy for the betterment of Alabama's citizens, communities, and businesses. As part of that mandate, the GSA has increasingly been called upon to make our data more accessible to stakeholders. Even as demand for greater data accessibility grows, budgets for such efforts are often small, meaning that agencies must do more for less. Agile software development has yielded efficient, effective products, most often at lower cost and in shorter time. Taking guidance from the agile software development model, the GSA is working towards more agile data management and curation. To date, the GSA's work has been focused primarily on data rescue. By using workflows that maximize clear communication while encouraging simplicity (e.g., maximizing the amount of work not done or that can be automated), the GSA is bringing decades of dark data into the light. Regular checks by the data rescuer with the data provider (or their proxy) provides quality control without adding an overt burden on either party. Moving forward, these workflows will also allow for more efficient and effective data management.

  14. An agile mask data preparation and writer dispatching approach

    NASA Astrophysics Data System (ADS)

    Hsu, Chih-tung; Chen, Y. S.; Hsin, S. C.; Tuo, Laurent C.; Schulze, Steffen F.

    2004-08-01

    An agile mask data preparation (MDP) approach is proposed to cut re-fracture cycle time as incurred by mask writer dispatching policy changes. Shorter re-fracture cycle time increases the flexibility of mask writer dispatching, as a result, mask writer's capacity can be utilized to its optimum. Preliminary results demonstrate promising benefits in MDP cycle time reduction and writer dispatching flexibility improvement. The agile MDP can save up to 40% of re-fracture cycle time. OASIS (Open Artwork System Interchange Standard) was proposed to address the GDSII file size explosion problem. However, OASIS has yet to gain wide acceptance in the mask industry. The authors envision OASIS adoption by the mask industry as a three-phase process and identify key issues of each phase from the mask manufacturer's perspective. As a long-term MDP flow reengineering project, an agile MDP and writer dispatching approach based on OASIS is proposed. The paper describes the results of an extensive evaluation on OASIS performance compared to that of GDSII, both original GDSII and post-OPC GDSII files. The file size of eighty percent of the original GDSII files is more than ten times larger compared to that of its OASIS counterpart.

  15. Observing peculiar γ-ray pulsars with AGILE

    NASA Astrophysics Data System (ADS)

    Pilia, M.; Pellizzoni, A.

    2011-08-01

    The AGILE γ-ray satellite provides large sky exposure levels (>=109 cm2 s per year on the Galactic Plane) with sensitivity peaking at E ~100 MeV where the bulk of pulsar energy output is typically released. Its ~1 μs absolute time tagging capability makes it perfectly suited for the study of γ-ray pulsars. AGILE collected a large number of γ-ray photons from EGRET pulsars (>=40,000 pulsed counts for Vela) in two years of observations unveiling new interesting features at sub-millisecond level in the pulsars' high-energy light-curves, γ-ray emission from pulsar glitches and Pulsar Wind Nebulae. AGILE detected about 20 nearby and energetic pulsars with good confidence through timing and/or spatial analysis. Among the newcomers we find pulsars with very high rotational energy losses, such as the remarkable PSR B1509-58 with a magnetic field in excess of 1013 Gauss, and PSR J2229+6114 providing a reliable identification for the previously unidentified EGRET source 3EG2227+6122. Moreover, the powerful millisecond pulsar B1821-24, in the globular cluster M28, is detected during a fraction of the observations.

  16. Automatic Beam Position Control at LASREF

    NASA Astrophysics Data System (ADS)

    Oothoudt, M. A.; Pillai, C.; Zumbro, M. V.

    1997-05-01

    Historically the Los Alamos Spallation Radiation Effects Facility (LASREF) has used manual control to position the 800 kW, 800 MeV proton beam on targets. New experiments, however, require more stringent position control more frequently than can be done manually for long periods of time. Data from an existing harp was used to automatically adjust steering magnets to maintain beam position to required tolerances. Results and details of the system will be presented.

  17. Recent studies of dispersion matched steering for the ILC bunch compressor and main linac

    SciTech Connect

    Lebrun, Paul L.G.; Michelotti, Leo P.; Ostiguy, Jean-Francois; /Fermilab

    2007-06-01

    The Dispersion Matched Steering (DMS) method is studied in detail in the context of a curved main linac. In the absence of cavity tilts (rotations in the YZ plane), DMS provides a unique and stable solution with negligible emittance growth. If cavity tilts are about 300 {micro}rad, the algorithm is not very robust. The emittance growth through the entire linac for positrons is about 5 nm, if the system is strictly static and statistical averaging can be used to improve beam position measurements. This growth is mostly eliminated if the dispersion and its derivative at injection can be adjusted. If anticipated ground motion, beam and klystron jitter, beam position measurement resolution are introduced (i.e. dynamical case), the emittance preservation goal is currently not achieved by DMS alone. Mitigation strategies are outlined.

  18. Final Report of the NASA Office of Safety and Mission Assurance Agile Benchmarking Team

    NASA Technical Reports Server (NTRS)

    Wetherholt, Martha

    2016-01-01

    To ensure that the NASA Safety and Mission Assurance (SMA) community remains in a position to perform reliable Software Assurance (SA) on NASAs critical software (SW) systems with the software industry rapidly transitioning from waterfall to Agile processes, Terry Wilcutt, Chief, Safety and Mission Assurance, Office of Safety and Mission Assurance (OSMA) established the Agile Benchmarking Team (ABT). The Team's tasks were: 1. Research background literature on current Agile processes, 2. Perform benchmark activities with other organizations that are involved in software Agile processes to determine best practices, 3. Collect information on Agile-developed systems to enable improvements to the current NASA standards and processes to enhance their ability to perform reliable software assurance on NASA Agile-developed systems, 4. Suggest additional guidance and recommendations for updates to those standards and processes, as needed. The ABT's findings and recommendations for software management, engineering and software assurance are addressed herein.

  19. Towards a Framework for Using Agile Approaches in Global Software Development

    NASA Astrophysics Data System (ADS)

    Hossain, Emam; Ali Babar, Muhammad; Verner, June

    As agile methods and Global Software Development (GSD) are become increasingly popular, GSD project managers have been exploring the viability of using agile approaches in their development environments. Despite the expected benefits of using an agile approach with a GSD project, the overall combining mechanisms of the two approaches are not clearly understood. To address this challenge, we propose a conceptual framework, based on the research literature. This framework is expected to aid a project manager in deciding what agile strategies are effective for a particular GSD project, taking into account project context. We use an industry-based case study to explore the components of our conceptual framework. Our case study is planned and conducted according to specific published case study guidelines. We identify the agile practices and agile supporting practices used by a GSD project manager in our case study and conclude with future research directions.

  20. Experimental demonstration of a multi-target detection technique using an X-band optically steered phased array radar.

    PubMed

    Shi, Nuannuan; Li, Ming; Deng, Ye; Zhang, Lihong; Sun, Shuqian; Tang, Jian; Li, Wei; Zhu, Ninghua

    2016-06-27

    An X-band optically-steered phased array radar is developed to demonstrate high resolution multi-target detection. The beam forming is implemented based on wavelength-swept true time delay (TTD) technique. The beam forming system has a wide direction tuning range of ± 54 degree, low magnitude ripple of ± 0.5 dB and small delay error of 0.13 ps/nm. To further verify performance of the proposed optically-steered phased array radar, three experiments are then carried out to implement the single and multiple target detection. A linearly chirped X-band microwave signal is used as radar signal which is finally compressed at the receiver to improve the detection accuracy. The ranging resolution for multi-target detection is up to 2 cm within the measuring distance over 4 m and the azimuth angle error is less than 4 degree.

  1. Experimental demonstration of a multi-target detection technique using an X-band optically steered phased array radar.

    PubMed

    Shi, Nuannuan; Li, Ming; Deng, Ye; Zhang, Lihong; Sun, Shuqian; Tang, Jian; Li, Wei; Zhu, Ninghua

    2016-06-27

    An X-band optically-steered phased array radar is developed to demonstrate high resolution multi-target detection. The beam forming is implemented based on wavelength-swept true time delay (TTD) technique. The beam forming system has a wide direction tuning range of ± 54 degree, low magnitude ripple of ± 0.5 dB and small delay error of 0.13 ps/nm. To further verify performance of the proposed optically-steered phased array radar, three experiments are then carried out to implement the single and multiple target detection. A linearly chirped X-band microwave signal is used as radar signal which is finally compressed at the receiver to improve the detection accuracy. The ranging resolution for multi-target detection is up to 2 cm within the measuring distance over 4 m and the azimuth angle error is less than 4 degree. PMID:27410597

  2. Certifying single-system steering for quantum-information processing

    NASA Astrophysics Data System (ADS)

    Li, Che-Ming; Chen, Yueh-Nan; Lambert, Neill; Chiu, Ching-Yi; Nori, Franco

    2015-12-01

    Einstein-Podolsky-Rosen (EPR) steering describes how different ensembles of quantum states can be remotely prepared by measuring one particle of an entangled pair. Here, we investigate quantum steering for single quantum d -dimensional systems (qudits) and devise efficient conditions to certify the steerability therein, which we find are applicable both to single-system steering and EPR steering. In the single-system case our steering conditions enable the unambiguous ruling out of generic classical means of mimicking steering. Ruling out "false-steering" scenarios has implications for securing channels against both cloning-based individual attack and coherent attacks when implementing quantum key distribution using qudits. We also show that these steering conditions also have applications in quantum computation, in that they can serve as an efficient criterion for the evaluation of quantum logic gates of arbitrary size. Finally, we describe how the nonlocal EPR variant of these conditions also function as tools for identifying faithful one-way quantum computation, secure entanglement-based quantum communication, and genuine multipartite EPR steering.

  3. 9 CFR 78.6 - Steers and spayed heifers.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... AGRICULTURE INTERSTATE TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS BRUCELLOSIS Restrictions on Interstate Movement of Cattle Because of Brucellosis § 78.6 Steers and spayed heifers....

  4. 9 CFR 78.6 - Steers and spayed heifers.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... AGRICULTURE INTERSTATE TRANSPORTATION OF ANIMALS (INCLUDING POULTRY) AND ANIMAL PRODUCTS BRUCELLOSIS Restrictions on Interstate Movement of Cattle Because of Brucellosis § 78.6 Steers and spayed heifers....

  5. Team-based work and work system balance in the context of agile manufacturing.

    PubMed

    Yauch, Charlene A

    2007-01-01

    Manufacturing agility is the ability to prosper in an environment characterized by constant and unpredictable change. The purpose of this paper is to analyze team attributes necessary to facilitate agile manufacturing, and using Balance Theory as a framework, it evaluates the potential positive and negative impacts related to these team attributes that could alter the balance of work system elements and resulting "stress load" experienced by persons working on agile teams. Teams operating within the context of agile manufacturing are characterized as multifunctional, dynamic, cooperative, and virtual. A review of the literature relevant to each of these attributes is provided, as well as suggestions for future research.

  6. Relationship Between Reactive Agility and Change of Direction Speed in Amateur Soccer Players.

    PubMed

    Matlák, János; Tihanyi, József; Rácz, Levente

    2016-06-01

    Matlák, J, Tihanyi, J, and Rácz, L. Relationship between reactive agility and change of direction speed in amateur soccer players. J Strength Cond Res 30(6): 1547-1552, 2016-The aim of the study was to assess the relationship between reactive agility and change of direction speed (CODS) among amateur soccer players using running tests with four directional changes. Sixteen amateur soccer players (24.1 ± 3.3 years; 72.4 ± 7.3 kg; 178.7 ± 6 cm) completed CODS and reactive agility tests with four changes of direction using the SpeedCourt™ system (Globalspeed GmbH, Hemsbach, Germany). Countermovement jump (CMJ) height and maximal foot tapping count (completed in 3 seconds) were also measured with the same device. In the reactive agility test, participants had to react to a series of light stimuli projected onto a screen. Total time was shorter in the CODS test than in the reactive agility test (p < 0.001). Nonsignificant correlations were found among variables measured in the CODS, reactive agility, and CMJ tests. Low common variance (r = 0.03-0.18) was found between CODS and reactive agility test variables. The results of this study underscore the importance of cognitive factors in reactive agility performance and suggest that specific methods may be required for training and testing reactive agility and CODS. PMID:26562713

  7. The influence of physical and cognitive factors on reactive agility performance in men basketball players.

    PubMed

    Scanlan, Aaron; Humphries, Brendan; Tucker, Patrick S; Dalbo, Vincent

    2014-01-01

    This study explored the influence of physical and cognitive measures on reactive agility performance in basketball players. Twelve men basketball players performed multiple sprint, Change of Direction Speed Test, and Reactive Agility Test trials. Pearson's correlation analyses were used to determine relationships between the predictor variables (stature, mass, body composition, 5-m, 10-m and 20-m sprint times, peak speed, closed-skill agility time, response time and decision-making time) and reactive agility time (response variable). Simple and stepwise regression analyses determined the individual influence of each predictor variable and the best predictor model for reactive agility time. Morphological (r = -0.45 to 0.19), sprint (r = -0.40 to 0.41) and change-of-direction speed measures (r = 0.43) had small to moderate correlations with reactive agility time. Response time (r = 0.76, P = 0.004) and decision-making time (r = 0.58, P = 0.049) had large to very large relationships with reactive agility time. Response time was identified as the sole predictor variable for reactive agility time in the stepwise model (R(2) = 0.58, P = 0.004). In conclusion, cognitive measures had the greatest influence on reactive agility performance in men basketball players. These findings suggest reaction and decision-making drills should be incorporated in basketball training programmes.

  8. Development of fast steering mirror control system for plasma heating and diagnostics

    SciTech Connect

    Okada, K. Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Tanaka, K.; Kobayashi, S.; Ito, S.; Mizuno, Y.; Ogasawara, S.; Nishiura, M.

    2014-11-15

    A control system for a fast steering mirror has been newly developed for the electron cyclotron heating (ECH) launchers in the large helical device. This system enables two-dimensional scan during a plasma discharge and provides a simple feedback control function. A board mounted with a field programmable gate array chip has been designed to realize feedback control of the ECH beam position to maintain higher electron temperature by ECH. The heating position is determined by a plasma diagnostic signal related to the electron temperature such as electron cyclotron emission and Thomson scattering.

  9. Development of fast steering mirror control system for plasma heating and diagnostics

    NASA Astrophysics Data System (ADS)

    Okada, K.; Nishiura, M.; Kubo, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Tanaka, K.; Kobayashi, S.; Ito, S.; Mizuno, Y.; Ogasawara, S.

    2014-11-01

    A control system for a fast steering mirror has been newly developed for the electron cyclotron heating (ECH) launchers in the large helical device. This system enables two-dimensional scan during a plasma discharge and provides a simple feedback control function. A board mounted with a field programmable gate array chip has been designed to realize feedback control of the ECH beam position to maintain higher electron temperature by ECH. The heating position is determined by a plasma diagnostic signal related to the electron temperature such as electron cyclotron emission and Thomson scattering.

  10. Development of fast steering mirror control system for plasma heating and diagnostics.

    PubMed

    Okada, K; Nishiura, M; Kubo, S; Shimozuma, T; Yoshimura, Y; Igami, H; Takahashi, H; Tanaka, K; Kobayashi, S; Ito, S; Mizuno, Y; Ogasawara, S

    2014-11-01

    A control system for a fast steering mirror has been newly developed for the electron cyclotron heating (ECH) launchers in the large helical device. This system enables two-dimensional scan during a plasma discharge and provides a simple feedback control function. A board mounted with a field programmable gate array chip has been designed to realize feedback control of the ECH beam position to maintain higher electron temperature by ECH. The heating position is determined by a plasma diagnostic signal related to the electron temperature such as electron cyclotron emission and Thomson scattering.

  11. Self-Balancing, Optical-Center-Pivot, Fast-Steering Mirror

    NASA Technical Reports Server (NTRS)

    Moore, James D.; Carson, Johnathan W.

    2011-01-01

    A complete, self-contained fast-steering- mirror (FSM) mechanism is reported consisting of a housing, a mirror and mirror-mounting cell, three PZT (piezoelectric) actuators, and a counterbalance mass. Basically, it is a comparatively stiff, two-axis (tip-tilt), self-balanced FSM. The present invention requires only three (or three pairs for flight redundancy) actuators. If a PZT actuator degrades, the inherent balance remains, and compensation for degraded stroke is made by simply increasing the voltage to the PZT. Prior designs typically do not pivot at the mirror optical center, creating unacceptable beam shear.

  12. 46 CFR 131.845 - Instructions for shift of steering gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... specify that each steering wheel or lever, and each rudder, must be amidships before any shift of steering gear or steering stations. (d) Each clutch, gear, wheel, lever, valve, or switch used during any...

  13. 46 CFR 131.845 - Instructions for shift of steering gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... specify that each steering wheel or lever, and each rudder, must be amidships before any shift of steering gear or steering stations. (d) Each clutch, gear, wheel, lever, valve, or switch used during any...

  14. 46 CFR 131.845 - Instructions for shift of steering gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... specify that each steering wheel or lever, and each rudder, must be amidships before any shift of steering gear or steering stations. (d) Each clutch, gear, wheel, lever, valve, or switch used during any...

  15. 46 CFR 131.845 - Instructions for shift of steering gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... specify that each steering wheel or lever, and each rudder, must be amidships before any shift of steering gear or steering stations. (d) Each clutch, gear, wheel, lever, valve, or switch used during any...

  16. 46 CFR 131.845 - Instructions for shift of steering gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... specify that each steering wheel or lever, and each rudder, must be amidships before any shift of steering gear or steering stations. (d) Each clutch, gear, wheel, lever, valve, or switch used during any...

  17. Auto-steering apparatus and method

    DOEpatents

    McKay, Mark D.; Anderson, Matthew O.

    2007-03-13

    A vehicular guidance method involves providing a user interface using which data can be input to establish a contour for a vehicle to follow, the user interface further configured to receive information from a differential global positioning system (DGPS), determining cross track and offset data using information received from the DGPS, generating control values, using at least vehicular kinematics, the cross track, and the offset data, and providing an output to control steering of the vehicle, using the control values, in a direction to follow the established contour while attempting to minimize the cross track and the offset data.

  18. Efficiency of lysine utilization by growing steers.

    PubMed

    Batista, E D; Hussein, A H; Detmann, E; Miesner, M D; Titgemeyer, E C

    2016-02-01

    This study evaluated the efficiency of Lys utilization by growing steers. Five ruminally cannulated Holstein steers (165 ± 8 kg) housed in metabolism crates were used in a 6 × 6 Latin square design; data from a sixth steer was excluded due to erratic feed intake. All steers were limit fed (2.46 kg DM/d), twice daily, diets low in RUP (81% soybean hulls, 8% wheat straw, 6% cane molasses, and 5% vitamins and minerals). Treatments were 0, 3, 6, 9, 12, and 15 g/d of Lys continuously abomasally infused. To prevent AA other than Lys from limiting performance, a mixture providing all essential AA to excess was continuously abomasally infused. Additional continuous infusions included 10 g urea/d, 200 g acetic acid/d, 200 g propionic acid/d, and 50 g butyric acid/d to the rumen and 300 g glucose/d to the abomasum. These infusions provided adequate ruminal ammonia and increased energy supply without increasing microbial protein supply. Each 6-d period included 2 d for adaptation and 4 d for total fecal and urinary collections for measuring N balance. Blood was collected on d 6 (10 h after feeding). Diet OM digestibility was not altered ( ≥ 0.66) by treatment and averaged 73.7%. Urinary N excretion was decreased from 32.3 to 24.3 g/d by increasing Lys supplementation to 9 g/d, with no further reduction when more than 9 g/d of Lys was supplied (linear and quadratic, < 0.01). Changes in total urinary N excretion predominantly were due to changes in urinary urea N. Increasing Lys supply from 0 to 9 g/d increased N retention from 21.4 to 30.7 g/d, with no further increase beyond 9 g/d of Lys (linear and quadratic, < 0.01). Break-point analysis estimated maximal N retention at 9 g/d supplemental Lys. Over the linear response surface of 0 to 9 g/d Lys, the efficiency of Lys utilization for protein deposition was 40%. Plasma urea N tended to be linearly decreased ( = 0.06) by Lys supplementation in agreement with the reduction in urinary urea N excretion. Plasma concentrations

  19. Two Optical-Beam-Forming Concepts For Array Antennas

    NASA Technical Reports Server (NTRS)

    Wu, Te-Kao; Chandler, C. W.

    1995-01-01

    Two optical-beam-forming concepts selected for development of phased-array antennas. Involve use of novel combinations of optical and electronic techniques to distribute radio-frequency signal to or from antenna elements in array: phase and amplitude of radio-frequency signal traveling to or from each element controlled in such way to cause array as whole to transmit or receive signal in desired spatial pattern, steered, narrowed, broadened, or otherwise varied. Techniques result in compact, lightweight beam-steering antennas. Potential applications include steered-beam or quasi-optical microwave antennas in communication and radar systems, remote control of antennas in general, and photonic communication. With some modifications, transmitting and receiving configurations incorporated into single system.

  20. Modeling of accelerator systems and experimental verification of Quarter-Wave Resonator steering

    NASA Astrophysics Data System (ADS)

    Benatti, Carla

    beam pipe, which has the potential to induce steering on the beam. These additional complications make this a significant device to study in order to optimize the accelerator's overall performance. The NSCL and ReA, along with FRIB, are first introduced to provide background and motivate the central modeling objectives presented throughout this work. In the next chapter, underlying beam physics principles are then discussed, as they form the basis from which modeling methods are derived. The modeling methods presented include multi-particle tracking and beam envelope matrix transport. The following chapter investigates modeling elements in more detail, including quadrupoles, solenoids, and coaxial accelerating cavities. Assemblies of accelerator elements, or lattices, have been modeled as well, and a method for modeling multiple charge state transport using linear matrix methods is also given. Finally, an experiment studying beam steering induced by QWR resonators is presented, the first systematic experimental investigation of this effect. As mentioned earlier, characterization of this steering on beam properties is important for accurate modeling of the beam transport through the linac. The measurement technique devised at ReA investigates the effect's dependence on the beam's vertical offset within the cavity, the cavity amplitude, and the beam energy upon entrance into the cavity. The results from this experiment agree well with the analytical predictions based on geometrical parameters calculated from on-axis field profiles. The incorporation of this effect into modeling codes has the potential to speed up complex accelerator operations and tuning procedures in systems using QWRs.