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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. Metamaterial-based Fabry-Pérot leaky wave antennas: low profile, high directivity, frequency agility and beam steering

    NASA Astrophysics Data System (ADS)

    Burokur, S. N.; de Lustrac, A.

    2013-04-01

    The analysis and design of subwavelength metamaterial-based Fabry-Pérot (FP) leaky wave antennas (LWAs) are presented. The antennas under investigation are formed by embedding a feeding source in a cavity composed of a Perfect Electrical Conductor (PEC) surface and a metasurface reflector. Several configurations of such antennas are presented to achieve different desired performances such as: high directivity, frequency agility and beam steering.

  3. 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.

  4. Wavelength agile nonmechanical laser beam steering from Fresnel zone plates imprinted on a liquid crystal spatial light modulator

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    Multibeam, multicolor, large-angle beam-steering is demonstrated in the visible spectral region by imprinting Fresnel zone plates (FZP) on a liquid crystal spatial light modulator. Spectral dispersion, both diffractive and refractive, is observed but does not prevent the use of this technology for beam steering applications. The experimental results show that while diffractive dispersion dominates over refractive dispersion, wavelength-specific FZPs can be rendered to direct those beams on target, either simultaneously or consecutively. Only a slight correction in the FZP positon is necessary to compensate for refractive dispersion. The position, intensity, and wavelength of each beam can be controlled independently.

  5. Studies of Non-Linear Optical Effects for Agile Beam Steering

    DTIC Science & Technology

    1993-11-01

    corresponded to: 1. An initial demonstration of the nonlinear optical enhancement effect in an off-the-shelf AO beam deflector . 2 . A demonstration of an...by showing an intensity-dependentertun• acousto - optic diffraction efficiency in a Tel) 2 Bragg ceUl un-ertures.der high-power pulsed illumination. The...proportional refractive-index d variation through the medium’s photoelastic response, the - d 2 (Ap)/dt- + v2V2 ( p) + ( 2 */0 2L,. - V(Ap) incident optical

  6. 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.

  7. Binary micro optics: An application to beam steering

    SciTech Connect

    Goltsos, W.; Holz, M.

    1989-01-01

    Agile steering of a helium-neon laser beam (lambda = 632.8nm) was demonstrated using a complementary pair of 5-cm-aperture diffractive microlens arrays in the Galilean telescopic geometry. Having as many as 60,000 F/5 microlenses, each with parabolic phase profile and 200 micrometers diameter, results in nearly aberration-free beam steering over 11 deg. field of view for top + or - 100 micrometers lateral displacements of one array relative to the other. Wavefront quality and steering efficiency of the deflected beam has been measured as a function of steering angle and is compared to a simple theoretical model.

  8. Beam steering device using CGHs

    NASA Astrophysics Data System (ADS)

    Yoon, Jin S.; An, Jun-Won; Kim, Nam; Sohn, Young-Jun; Suh, Dongwoo; Baek, Mun-Chul

    2003-05-01

    A new beam steering scheme using computer-generated holograms(CGHs) is proposed. The steering devices in order to control the reference and object wave are necessary in various holographic multiplexing methods. The beam steering device using CGHs can be simultaneously processed the coarse address function controlling the beam up or down so as to select slice and the fine address function adjusting to the particular holographic page within the chosen layer. From the experimental results, we show that the beam steering can be easily implemented and so powerful to generate the electrically addressed reference wave in digital holographic memory system.

  9. 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.

  10. Acousto-Optic Beam Steering Study

    DTIC Science & Technology

    1994-08-01

    8217111 INK $ 1 1 illl iII Ill i, R L-TR-94-121 !1!1Il t 11I1!I!11! ilI, / Final Technical Report August 1994 ACOUSTO - OPTIC BEAM STEERING STUDY Harris...contractual obligations or notices on a specific document require that it be returned. For i ..........I ,, ACOUSTO - OPTIC BEAM STEERING STUDY H. W...4. TITLE AND SUBTITLE 5. FUNDING NUMBERS ACOUSTO - OPTIC BEAM STEERING STUDY C - F30602-91-C-0131 PE - 63215C 6. AUTHOR(S) PR - 1405 TA - 02 H. W

  11. 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.

  12. 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.

  13. 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.

  14. Highly sensitive beam steering with plasmonic antenna.

    PubMed

    Rui, Guanghao; Zhan, Qiwen

    2014-08-05

    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.

  15. Self-steering partially coherent beams

    NASA Astrophysics Data System (ADS)

    Chen, Yahong; Ponomarenko, Sergey A.; Cai, Yangjian

    2017-01-01

    We introduce a class of shape-invariant partially coherent beams with a moving guiding center which we term self-steering partially coherent beams. The guiding center of each such beam evolves along a straight line trajectory which can be engineered to make any angle with the x-axis. We show that the straight line trajectory of the guiding center is the only option in free space due to the linear momentum conservation. We experimentally generate a particular subclass of new beams, self-steering Gaussian Schell beams and argue that they can find applications for mobile target tracing and trapped micro- and/or nanoparticle transport.

  16. Self-steering partially coherent beams

    PubMed Central

    Chen, Yahong; Ponomarenko, Sergey A.; Cai, Yangjian

    2017-01-01

    We introduce a class of shape-invariant partially coherent beams with a moving guiding center which we term self-steering partially coherent beams. The guiding center of each such beam evolves along a straight line trajectory which can be engineered to make any angle with the x-axis. We show that the straight line trajectory of the guiding center is the only option in free space due to the linear momentum conservation. We experimentally generate a particular subclass of new beams, self-steering Gaussian Schell beams and argue that they can find applications for mobile target tracing and trapped micro- and/or nanoparticle transport. PMID:28051164

  17. 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.

  18. 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.

  19. Optomechanical beam steering by surface plasmon nanoantenna

    NASA Astrophysics Data System (ADS)

    Bonakdar, Alireza; Kohoutek, John; Mohseni, Hooman

    2012-09-01

    Controlling the far field pattern of the electromagnetic (EM) waves has many applications including wireless communications, radar detection, and industrial applications. The dynamic control of EM patterns is called beam steering. Despite advantages in each technique, the speed, angular range, and spectral range of beam steering is limited due to mechanical and optical properties of such systems. Here we present a beam steering method by means of an array of optomechanical nanoantennas in which the generated optical force of each antenna results in changes to the antenna response due to mechanical reconfiguration. As a result, the antenna far field phase is changed due to the mechanical movement generated by the optical force. Depending on the mechanical properties of the movable component of the antenna, the phase of the antenna can be tailored for a given optical source power. FDTD simulations are used to calculate the optical response of antenna. A phase array of optomechanical nanoantennas is used to do beam steering. The main far field lobe is steered by 0.5 degrees as a result of the mechanical reconfiguration of the phased array.

  20. 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.

  1. 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.

  2. 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.

  3. Design and optimization of microlens array based high resolution beam steering system.

    PubMed

    Akatay, Ata; Urey, Hakan

    2007-04-16

    High-resolution imaging and beam steering using 3 microlens arrays (MLA) is demonstrated. Small lateral displacement of one microlens array is sufficient for large angle beam steering. A prescan lens is added to the system to overcome the discrete addressing problem associated with microlens scanning systems. A hybrid method that uses both geometrical ray tracing optimization and physical optics simulation is introduced for the design and optimization of the MLA system. Feasibility of 1880 x 1880 resolution using f/2 aspherical MLAs and 752 x 752 resolution using f/5 spherical MLAs are demonstrated assuming 100 microm microlens pitch and 2mm clear aperture. The system is compact and suitable for endoscopic imaging and agile steering of large beams.

  4. 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

  5. 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.

  6. 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.

  7. Dynamic two-dimensional beam-pattern steering technique

    NASA Astrophysics Data System (ADS)

    Zhou, Shaomin; Yeh, Pochi; Liu, Hua-Kuang

    1993-06-01

    A dynamic two-dimensional laser-beam-pattern steering technique using photorefractive holograms in conjunction with electrically addressed spatial light modulators is proposed and investigated. The experimental results demonstrate the dynamic steering of random combinations of basis beam patterns. The proposed method has the advantages of random beam-pattern combination, good beam intensity uniformity, and higher diffraction efficiency compared with conventional methods.

  8. Steering electromagnetic beams with conical curvature singularities.

    PubMed

    Zhang, Yong-Liang; Dong, Xian-Zi; Zheng, Mei-Ling; Zhao, Zhen-Sheng; Duan, Xuan-Ming

    2015-10-15

    We describe how the transformation-optics technique can be used to design an effective medium mimicking the conical curvature singularity. Anholonomic coordinate transformation gives rise to linear topological defects that break the rotational symmetry. The bending and splitting of the optical beams are found analytically and numerically, depending on the incident direction and the topological charge. Beyond their practical applications to omnidirectional beam steering for photonics, our findings set forth an attractive realm to simulate the relevant physical phenomena in the optical laboratory.

  9. Beam steering using CGHs in spatial multiplexing method

    NASA Astrophysics Data System (ADS)

    Yoon, Jin-Seon; Kim, Nam

    2002-09-01

    In spatial multiplexing method, the steering devices for reference wave and object wave are necessary. A new scheme applying computer-generated holograms(CGHs) to the steering device is proposed. The beam steering device using CGHs can be performed simultaneously the coarse address function directing the reading or writing beams to the suitable layer and the fine address function corresponding to the particular holographic page within the chosen common volume unit. This new scheme is compared with both the beam steering method using spatial/angular multiplex AODs and the mechanically steered method in terms of access time, cost, and efficiency.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Two dimensional array imaging with beam steered data.

    PubMed

    Patole, Sujeet; Torlak, Murat

    2013-12-01

    This paper discusses different approaches used for millimeter wave imaging of 2D objects. Imaging of a 2D object requires reflected wave data to be collected across two distinct dimensions. In this paper, we propose a reconstruction method that uses narrowband waveforms along with 2D beam steering. The beam is steered in azimuthal and elevation direction, which forms the two distinct dimensions required for the reconstruction. The reconstruction technique uses inverse Fourier transform along with amplitude and phase correction factors. In addition, this reconstruction technique does not require interpolation of the data in either wavenumber or spatial domain. Use of the 2D beam steering offers better performance in the presence of noise compared with the existing methods, such as switched array imaging system. Effects of radio-frequency impairments such as quantization of the phase of beam steering weights and timing jitter, which add to phase noise, are analyzed.

  17. Low-Absorption Liquid Crystals for Infrared Beam Steering

    DTIC Science & Technology

    2015-09-30

    am2 and JE:=521.37meV. Thus, such large viscosity results in slow response time, which is not preferred in the beam steering applications ...liquid crystals for infrared laser beam steering applications . To suppress the optical loss in MW1R and LW1R, we have investigated following...pi phase change at MW1R and response time less than 4ms. To extend the potential applications into LWIR, we synthesized several chlorinated teiphenyl

  18. Multiplexed broadband beam steering system utilizing high speed MEMS mirrors.

    PubMed

    Knoernschild, Caleb; Kim, Changsoon; Lu, Felix P; Kim, Jungsang

    2009-04-27

    We present a beam steering system based on micro-electromechanical systems technology that features high speed steering of multiple laser beams over a broad wavelength range. By utilizing high speed micromirrors with a broadband metallic coating, our system has the flexibility to simultaneously incorporate a wide range of wavelengths and multiple beams. We demonstrate reconfiguration of two independent beams at different wavelengths (780 and 635 nm) across a common 5x5 array with 4 micros settling time. Full simulation of the optical system provides insights on the scalability of the system. Such a system can provide a versatile tool for applications where fast laser multiplexing is necessary.

  19. 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.

  20. 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.

  1. Resonant Transmissive Modulator Construction for Use in Beam Steering Array

    NASA Technical Reports Server (NTRS)

    Keys, Andrew S.; Fork, Richard L.; Nelson, Thomas R.; Loehr, John P.

    1999-01-01

    An agile electronically configurable optical beam steering device for use in directional free-space transmission of optical signals is described. The device design employs an array of tunable resonant transmissive modulators constructed from multi-layered stacks of electro-optically active dielectric materials. Each modulator may be individually configured to transmit an optical signal with a specific amount of phase and group velocity modulation. The resulting diffractive interactions between modulator outputs provide a method for directional optical signal transmission. Of particular focus within this presentation is the optimized design of the individual modulator. It is widely known that periodic multi-layered stacks of dielectric materials exhibit reflective and transmissive resonances as described by the stack's transmission function. If an electric field is applied normal to the stack's layers, phenomena such as the electro-optic effect and/or the quantum-confined Stark effect may be employed to change the effective refractive index within the stack. This refractive index change alters the stack's transmission function and modulates the phase and group velocity of the transmitted optical signal. By varying the parameters that describe the stack's specific construction and operation, such as number of layers within the stack, refractive indexes of stack materials, layer thicknesses, and combinations of periodic verses non-periodic layer repetitions, custom transmittance functions may be generated. The transmitted optical signal carrier frequency and bandwidth must be carefully selected to maximize transmission and to minimize absorption. A computational optimization of the variables describing the stack's construction strives to maximize the amount of optical signal modulation verses applied voltage. Trade-offs between methods of increasing device performance verses the limitations of fabrication technologies are considered.

  2. Laser beam steering via wave mixing in volumetric thermal gratings

    NASA Astrophysics Data System (ADS)

    Tyler, David W.

    1992-06-01

    A volumetric thermal grating (VTG) is a spatially periodic refractive index variation in a volume of gas or liquid, generated by imaging interference fringes into the medium. The fringes can be created and varied by steering laser write beams electronically with acousto- optic (A-O) cells. While the wavelength of the write beams is chosen to be absorbed by a dopant in the VTG medium, a read beam at an off-resonance wavelength can be manipulated by diffraction from the resulting index grating. Potential applications include resonator and amplifier optical isolation prepulse suppression in high-gain amplifiers, noninertial steering of large-diameter laser beams, transfer of phase information between beams to facilitate adaptive optics, Q-switching of chemical lasers, and line selection in broadband lasers. In this paper, we present a preliminary assessment of VTG utility for these optical systems applications by quantitative analysis of the medium density dynamics. In Section 2, we derive a relation between A-O acoustic frequency uncertainty and VTG pointing/steering uncertainty, which also scales desired steering range to required A-O frequency modulation bandwidth. In Section 3, we discuss the temporal response of a doped rare-gas VTG medium. Section 4 is an assessment of VTG beam-steering performance potential using available technology.

  3. Highly efficient beam steering with a transparent metasurface.

    PubMed

    Wei, Zeyong; Cao, Yang; Su, Xiaopeng; Gong, Zhijie; Long, Yang; Li, Hongqiang

    2013-05-06

    We propose an ultra-thin planar metasurface with phase discontinuities for highly efficient beam steering. The effect benefits from the broadband transparency and flexible phase modulation of stacked metal/dielectric multi-layers that is perforated with coaxial annular apertures. Proof-of-principle experiments verify that an efficiency of 65% and a deflection angle of 18° at 10 GHz are achieved for the transmitted beam, which are also in good agreement with the finite-difference-method-in-time-domain (FDTD) simulations. The scheme shall be general for the design of beam-steering transmitters in all frequencies.

  4. 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.

  5. Diffraction Efficiency of Thin Film Holographic Beam Steering Devices

    NASA Astrophysics Data System (ADS)

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

    2003-02-01

    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.

  6. 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.

  7. 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.

  8. 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.

  9. Terahertz beam steering using interference of femtosecond optical pulses.

    PubMed

    Uematsu, Koji; Maki, Ken-ichiro; Otani, Chiko

    2012-09-24

    A terahertz (THz) beam steering method is demonstrated by applying the characteristic of grating lobe (GL) radiation from a linear array antenna and the interference of femtosecond optical pulses. A photoconductive device is illuminated by two femtosecond laser beams combined at an angle of less than 0.5°. Considering the interference pattern as a THz point source array, THz GL radiation is generated through the superposition of radiation emitted from all point sources and steered by varying the interval of the interference pattern. The THz beam direction could be changed by 20° at 0.93THz by varying the relative incidence angle of the pump beams by 0.033°.

  10. Simulation research on beam steering technology based on optical phased array

    NASA Astrophysics Data System (ADS)

    Tian, Junlin; Pan, Xudong

    2015-02-01

    The principle of beam steering technology based on optical phased array (OPA), which is composed of individual phase-modulating units, is introduced. By use of Fraunhofer diffraction and Fourier transformation, the OPA models are established. The influence of main parameters of OPA on beam steering efficiency, including duty ratio (ratio of effective unit size to total unit size), total unit size, unit number, and steering angle, is simulated and analyzed. It shows that beam steering efficiency of OPA is improved with larger duty ratio, smaller total unit size, and smaller steering angle, while the number of units has a very small impact on beam steering efficiency.

  11. Performance characterization of scanning beam steered by tilting double prisms.

    PubMed

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

    2016-10-03

    A pair of orthogonal tilting double prisms with a tracking precision better than submicroradian order exhibits a good application potential in laser tracking fields. In the paper, the beam scanning performance determined by both the structure parameters and the tilting motions of two prisms is overall investigated. The functional relation between the structure parameters and the exact beam scanning range is established, the capability of high-accuracy beam steering is validated together with the investigation of the scanning error sources and the nonlinear control laws, and the beam shape distortion degree under multi-parameter combinations is demonstrated. These studies can provide important references for the development of tilting double prisms.

  12. 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.

  13. 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.

  14. Reconfigurable time-steered array-antenna beam former.

    PubMed

    Frankel, M Y; Esman, R D

    1997-12-10

    We present and analyze a hardware-optimized technique that provides true-time-delay steering for broadband two-dimensional array-antenna applications. The technique improves on previous approaches by the reduction of the two-dimensional beam-former architecture complexity, by the provision of flexibility in time-delay unit selection, and by the potential reduction of optical loss. The technique relies on a one-dimensional bank of time-delay units to form the required time-delay gradient for proper off-broadside angle steering. A reconfigurable optical interconnection fabric is used to reassign dynamically the connections between the time-delay units and individual array elements of a two-dimensional array to effect the proper steering angle along the off-broadside cone.

  15. Tunable two dimensional optical beam steering with reconfigurable indium tin oxide plasmonic reflectarray metasurface

    NASA Astrophysics Data System (ADS)

    Forouzmand, A.; Mosallaei, H.

    2016-12-01

    In this paper, an electrically tunable reflectarray metasurface for two dimensional (2D) beam steering is designed by integration of a thin layer of indium tin oxide (ITO) material into a metal-insulator-metal (MIM) plasmonic unit-cell. The reflectarray is composed of square-shaped patch nanoantennas placed on a stack of insulator-ITO-metallic ground plane. The resonant characteristic of unit-cell and the accumulation of carrier density at the interface of ITO-insulator play key roles in obtaining over 250° of phase agility at around 218 terahertz (THz), by electrically varying the bias voltage. An array of unit-cells with integrated ITO and 2D voltage biasing distribution (from the side) offer the possibility of designing a reconfigurable antenna in which the main beam can be steered to relatively large angles in both θ- and φ- planes at carefully selected operating frequency. The significant advantage of this design is the dynamically adjustable radiation pattern in both azimuth and elevation planes even after fabrication.

  16. Electro-Optic Beam Steering Using Domain Engineered Lithium Tantalate

    DTIC Science & Technology

    2005-03-01

    becomes (ne + ∆ne) d = ned + ∆ned. (6.1) where ∆ne is the electro- optically induced change in the index. Combining with Equation 2.32 ∆ned = ± 1 2 ...utilizing numerous electro-mechanical, acousto - optic and electro- optic steering mechanisms [3, 7, 14,15,17,18]. As a special motivation for this...angle electro- optic beam scanner,(b) Gradient type electro- optic beam scanner, (c)Prism type electro- optic beam scanner. 2 Additional attempts to

  17. Theoretical modeling on the laser induced effect of liquid crystal optical phased beam steering

    NASA Astrophysics Data System (ADS)

    He, Xiaoxian; Wang, Xiangru; Wu, Liang; Tan, Qinggui; Li, Man; Shang, Jiyang; Wu, Shuanghong; Huang, Ziqiang

    2017-01-01

    Non-mechanical laser beam steering has been reported previously in liquid crystal array devices. To be one of the most promising candidates to be practical non-mechanical laser deflector, its laser induced effect still has few theoretical model. In this paper, we propose a theoretical model to analyze this laser induced effect of LC-OPA to evaluate the deterioration on phased beam steering. The model has three parts: laser induced thermal distribution; temperature dependence of material parameters and beam steering deterioration. After these three steps, the far field of laser beam is obtained to demonstrate the steering performance with the respect to the incident laser beam power and beam waist.

  18. 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.

  19. Conceptual design of a beam steering lens through transformation electromagnetics.

    PubMed

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

    2015-05-18

    In this paper, based on transformation electromagnetics, the design procedure of a lens antenna, which steers the radiated beam of a patch array, is presented. Laplace's equation is adopted to construct the mapping between the virtual space and the physical space. The two dimensional (2D) design method can be extended to a potential three-dimensional (3D) realization, and with a proper parameter simplification, the lens can be further realized by common metamaterials or isotropic graded refractive index (GRIN) materials. Full wave simulations are performed to validate the proposed concept. It is observed that by placing the lens on a feeding source, we are able to steer the radiation emitted by the latter source.

  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. A Novel Microwave Beam Steering Technique Using Plasma

    NASA Astrophysics Data System (ADS)

    Linardakis, Peter; Borg, Gerard G.; Harris, Jeffrey H.; Martin, Noel M.

    2002-10-01

    At frequencies above the plasma frequency, electromagnetic waves propagate through plasma with a wavelength longer than the free space wavelength. As a result, a plasma with a centrally peaked density profile can deflect rather than focus electromagnetic waves. We present a plasma device designed specifically to deflect a microwave beam as an alternative to conventional beam deflectors based on antenna arrays. A 22^rc deflection of Ka band microwave has been achieved using a laboratory plasma, with no detrimental effect on the beamwidth or side-lode level and structure. The use of a simple WKB model shows agreement and that the deflection can be increased with appropriate design. Results indicate the potential for increases in dynamic range, in power handling (for example from a gyrotron) and for the reduction of insertion losses over current beam steering systems. A ``plasma lens'' demonstrator device has also been designed to test practical performance aspects such as phase noise and to test optimization parameters.

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

    PubMed

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

    2016-10-14

    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.

  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. 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.

  5. Nonmechanical Infrared Beam Steering Using Blue Addressed Quantum Dot Doped Liquid Crystal Grating.

    PubMed

    Wang, Xiangru; Huang, Xiaoping; Huang, Ziqiang; Wu, Liang; Shang, Jiyang; Qiu, Qi; Wu, Shuanghong

    2017-12-01

    We present a scheme of nonmechanical laser beam steering using ZnS/InP quantum dots doping nematic liquid crystal as the optical recording film. Because of its internal electric field generated by blue laser-induced charge carrier distribution, liquid crystal molecules are reoriented to form a phase grating which make the incident angle steer to the angle as we desire. Being a nonmechanical programmable laser beam steering, the anisotropy of the relative permittivity tensor and blue laser-induced electric carriers play a significant effect in determining the reorientable liquid crystal molecule and reconfigurable phase modulation of the gratings, that determines the steering angle and steering efficiency.

  6. Nonmechanical Infrared Beam Steering Using Blue Addressed Quantum Dot Doped Liquid Crystal Grating

    NASA Astrophysics Data System (ADS)

    Wang, Xiangru; Huang, Xiaoping; Huang, Ziqiang; Wu, Liang; Shang, Jiyang; Qiu, Qi; Wu, Shuanghong

    2017-01-01

    We present a scheme of nonmechanical laser beam steering using ZnS/InP quantum dots doping nematic liquid crystal as the optical recording film. Because of its internal electric field generated by blue laser-induced charge carrier distribution, liquid crystal molecules are reoriented to form a phase grating which make the incident angle steer to the angle as we desire. Being a nonmechanical programmable laser beam steering, the anisotropy of the relative permittivity tensor and blue laser-induced electric carriers play a significant effect in determining the reorientable liquid crystal molecule and reconfigurable phase modulation of the gratings, that determines the steering angle and steering efficiency.

  7. 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.

  8. Laser beam steering approaches for microstructuring of copper layers

    NASA Astrophysics Data System (ADS)

    Mur, Jaka; Podobnik, Boštjan; Poberaj, Igor

    2017-02-01

    We have investigated the process of copper layer ablation with a tightly focused Q-switched 532 nm laser. Focusing 40 ns long laser pulses to a micrometer-sized spot results in high energy density and gives rise to ablation phenomena not seen during laser processing with larger beam diameters. Use of acousto-optic deflectors (AODs) enabled us to test different laser beam steering approaches in terms of choosing the position for each laser pulse independently of the previous pulses. Random addressing of desired positions across a microstructure proved to be the most efficient method compared to various scanning approaches. Assigning a random order to the spatial sequence of laser pulses resulted in the fastest microstructuring process and featured lowest residual heating of the substrate.

  9. 1-D ELECTRO-OPTIC BEAM STEERING DEVICE.

    PubMed

    Wang, Wei-Chih; Tsui, Chi Leung

    2011-06-05

    In this paper, we present the design and fabrication of a 1D beam steering device based on planar electro-optic thermal-plastic prisms and a collimator lens array. With the elimination of moving parts, the proposed device is able to overcome the mechanical limitations of present scanning devices, such as fatigue and low operating frequency, while maintaining a small system footprint (~0.5mm×0.5mm). From experimental data, our prototype device is able to achieve a maximum deflection angle of 5.6° for a single stage prism design and 29.2° for a cascaded three prisms stage design. The lens array shows a 4µm collimated beam diameter.

  10. Creating and Steering Highly Directional Electron Beams in Graphene

    NASA Astrophysics Data System (ADS)

    Liu, Ming-Hao; Gorini, Cosimo; Richter, Klaus

    2017-02-01

    We put forward a concept to create highly collimated, nondispersive electron beams in pseudorelativistic Dirac materials such as graphene or topological insulator surfaces. Combining negative refraction and Klein collimation at a parabolic p n junction, the proposed lens generates beams, as narrow as the focal length, that stay focused over scales of several microns and can be steered by a magnetic field without losing collimation. We demonstrate the lens capabilities by applying it to two paradigmatic settings of graphene electron optics: We propose a setup for observing high-resolution angle-dependent Klein tunneling, and, exploiting the intimate quantum-to-classical correspondence of these focused electron waves, we consider high-fidelity transverse magnetic focusing accompanied by simulations for current mapping through scanning gate microscopy. Our proposal opens up new perspectives for next-generation graphene electron optics experiments.

  11. 1-D ELECTRO-OPTIC BEAM STEERING DEVICE

    PubMed Central

    Wang, Wei-Chih; Tsui, Chi Leung

    2011-01-01

    In this paper, we present the design and fabrication of a 1D beam steering device based on planar electro-optic thermal-plastic prisms and a collimator lens array. With the elimination of moving parts, the proposed device is able to overcome the mechanical limitations of present scanning devices, such as fatigue and low operating frequency, while maintaining a small system footprint (~0.5mm×0.5mm). From experimental data, our prototype device is able to achieve a maximum deflection angle of 5.6° for a single stage prism design and 29.2° for a cascaded three prisms stage design. The lens array shows a 4µm collimated beam diameter. PMID:22199458

  12. Variations in proton scanned beam dose delivery due to uncertainties in magnetic beam steering.

    PubMed

    Peterson, Stephen; Polf, Jerimy; Ciangaru, George; Frank, Steven J; Bues, Martin; Smith, Al

    2009-08-01

    The purpose of this work was to develop a method to calculate and study the impact of fluctuations in the magnetic field strengths within the steering magnets in a proton scanning beam treatment nozzle on the dose delivered to the patient during a proton therapy treatment. First, an analytical relationship between magnetic field uncertainties in the steering magnets and the resulting lateral displacements in the position of the delivered scanned beam "dose spot" was established. Next, using a simple 3D dose calculation code and data from a validated Monte Carlo model of the proton scanning beam treatment nozzle, the uniform dose delivery to a 3D treatment volume was calculated. The dose distribution was then recalculated using the calculated lateral displacements due to magnetic field fluctuations to the proton pencil beam position. Using these two calculated dose distributions, the clinical effects of the magnetic field fluctuations were determined. A deliberate displacement of four adjacent spots either toward or away from each other was used to determine the "maximum" dose impact, while a random displacement of all spots was used to establish a more realistic clinical dose impact. Changes in the dose volume histogram (DVH) and the presence of hot and cold spots in the treatment volume were used to quantify the impact of dose-spot displacement. A general analytical relationship between magnetic field uncertainty and final dose-spot position is presented. This analytical relationship was developed such that it can be applied to study magnetic beam steering for any scanned beam nozzle design. Using this relationship the authors found for the example beam steering nozzle used in this study that deliberate lateral displacements of 0.5 mm or random lateral displacements of up to 1.0 mm produced a noticeable dose impact (5% hot spot) in the treatment volume. A noticeable impact (3% decrease in treatment volume coverage) on the DVH was observed for random displacements

  13. The compensation of the PC beam of the scattered beam by a foam target with FWM for beam steering

    NASA Astrophysics Data System (ADS)

    Kameyama, Nobukazu; Yoshida, Hiroki

    2012-10-01

    It is necessary for the direct IFE to irradiate a target with laser beams. The laser beams have to be steered for accurate laser irradiation since the target is injected at several hundreds meters per second. The method of beam steering with phase conjugate mirrors is one of the candidates. In the method, probe beams whose energies are low enough not to damage it and expanded larger than the target radius are illuminated the target. The scattered beam enters into the phase conjugate mirrors and the phase conjugate beam is generated in the opposite direction of it. The phase conjugate beam retraces the same path for the property and irradiated the target. As the target has moved several hundreds micrometers for the high speed when the phase conjugate beam comes back, it is necessary for the phase conjugate beam to compensate for accurate irradiation. Four wave mixing is used as the compensation way. The interaction of two counter-propagating pump beams and a seed beam generates a phase conjugate beam in four wave mixing. The phase conjugate beam is adjustable by setting the angle between two pump beams. The compensation with a scattered beam by a foam target as a seed beam is reported.

  14. Optical design in beam steering environments with emphasis on laser transmission measurements.

    PubMed

    Kranendonk, Laura A; Sanders, Scott T

    2005-11-01

    Optical sensors applied to practical devices often encounter beam steering: the wander and/or diffusion of laser light. Here we provide a framework for minimizing the sensitivity of transmission-based sensors to beam steering without quantitative prediction of the severity of the beam-steering field. Typical goals are increased transmission and/or minimized fluctuations in transmission; such features can improve optical sensor performance (e.g., improved signal-to-noise ratio, response time, or spectral resolution). In our framework, we introduce a parameter for characterizing beam-steering severity. We then compare two approaches for absorption spectroscopy and show that the preferred approach depends on the total spectral range monitored, the spectral resolution desired, and the severity of the beam steering.

  15. Beam steering and impedance matching of plasmonic horn nanoantennas

    NASA Astrophysics Data System (ADS)

    Afridi, Adeel; Kocabaş, Şükrü Ekin

    2016-10-01

    In this paper, we study a plasmonic horn nanoantenna on a metal-backed substrate. The horn nanoantenna structure consists of a two-wire transmission line (TWTL) flared at the end. We analyze the effect of the substrate thickness on the nanoantenna's radiation pattern, and demonstrate beam steering in a broad range of elevation angles. Furthermore, we analyze the effect of the ground plane on the impedance matching between the antenna and the TWTL, and observe that the ground plane increases the back reflection into the waveguide. To reduce the reflection, we develop a transmission line model to design an impedance matching section which leads to 99.75% power transmission to the nanoantenna.

  16. Beam steering and impedance matching of plasmonic horn nanoantennas.

    PubMed

    Afridi, Adeel; Kocabaş, Şükrü Ekin

    2016-10-31

    In this paper, we study a plasmonic horn nanoantenna on a metal-backed substrate. The horn nanoantenna structure consists of a two-wire transmission line (TWTL) flared at the end. We analyze the effect of the substrate thickness on the nanoantenna's radiation pattern, and demonstrate beam steering in a broad range of elevation angles. Furthermore, we analyze the effect of the ground plane on the impedance matching between the antenna and the TWTL, and observe that the ground plane increases the back reflection into the waveguide. To reduce the reflection, we develop a transmission line model to design an impedance matching section which leads to 99.75% power transmission to the nanoantenna.

  17. Electrically Switched Holographic Film for High Speed Optical Beam Steering

    NASA Astrophysics Data System (ADS)

    Sutherland, R. L.; Natarajan, L. V.; Tondiglia, V. P.; Bunning, T. J.

    1997-03-01

    We have developed a novel composite material which forms electrically switchable gratings upon standard holographic recording. The gratings consist of periodic arrays of nanometer scale liquid crystal domains in a dense polymer host. NMR and SEM studies indicate a homeotropic alignment of the liquid crystal with an axial defect or symmetry axis along the long axis of prolate sheroid droplets. Samples exhibit good optical quality with high diffraction efficiency in a single Bragg mode. The diffraction efficiency can be modulated by an external electric field, and wide on/off dynamic range switching (>25 dB) is achieved. Simple models relate the dynamic range, switching voltage (<5 V/μm), and response time (25 μs) to the material morphology. Applications incorporating high speed beam steering will be discussed.

  18. 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.

  19. Ultrafast beam steering using gradient Au-Ge₂Sb₂Te₅-Au plasmonic resonators.

    PubMed

    Cao, Tun; Zheng, Guangzhao; Wang, Shuai; Wei, Chenwei

    2015-07-13

    Beam steering devices have gained extensive interests in the fields of optical interconnects, communications, displays and data storages. However, the challenge lies in obtaining an ultrafast beam steering structure in the optical regime. Here, we propose phase-array-like plasmonic resonators based on metal/phase-change materials (PCMs)/metal trilayers for all-optical ultrafast beam steering in the mid-infrared (MIR) region. We numerically demonstrate an angle beam steering of 11° for transmitted wave (front lobe) and 22° for reflected wave (back lobe) by switching between the amorphous and crystalline states of the PCM (Ge₂Sb₂Te₅). A photothermal model is used to study the temporal variation of the temperature of the Ge₂Sb₂Te₅ film to show potential for switching the phase of Ge₂Sb₂Te₅ by optical heating. Generation of the beam steering in this structure exhibits a fast beam steering time of 3.6 ns under a low pump light intensity of 2.6 μW/μm₂. Our design possesses a simple geometry which can be fabricated using standard photolithography patterning and is essential for exploiting the ultrafast beam steering in various applications in the MIR regime.

  20. 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.

  1. High-speed high-density holographic memory using electro-optic beam steering devices

    NASA Astrophysics Data System (ADS)

    Chao, Tien-Hsin; Zhou, Hanying; Reyes, George F.; Dragoi, Danut; Hanan, Jay

    2002-11-01

    An innovative compact holographic memory system will be presented. This system utilizes a new electro-optic (E-O) beam steering technology to achieve high-speed, high-density holographic data storage.

  2. Experimental research on beam steering characteristics of liquid crystal optical phased array

    NASA Astrophysics Data System (ADS)

    Li, Man; Cai, Jun; Xu, Hong; Wang, Xiangru; Wu, Liang

    2016-01-01

    Beam steering characteristics of transmission liquid crystal optical phased array(LC-OPA) were measured using ultra precision electronic autocollimator. A continuous beam steering with a constant angular resolution in the order of 20 μrad is obtained experimentally from 0° to 6° based on the method of variable period grating (VPG).Meanwhile, the angular repeatability of less than 4 μrad (RMS) has been achieved.

  3. Bidimensional phase-varying metamaterial for steering beam antenna

    NASA Astrophysics Data System (ADS)

    Ourir, Abdelwaheb; Burokur, Shah Nawaz; de Lustrac, André

    2007-05-01

    Dielectric substrates supporting planar periodic subwavelength metamaterial-based metallic arrays and presenting frequency dispersive phase characteristics are applied to ultra-compact high-gain and high-directivity planar antennas. In this paper, different models of metamaterial-based surfaces introducing a zero degree reflection phase shift to incident waves are firstly studied numerically using finite-element method analysis where the bandwidth and operation frequency are predicted. These surfaces are then applied in a resonant Fabry-Perot type cavity and a ray optics analysis is used to design different models of ultra-compact high-gain microstrip printed antennas. Firstly, a cavity antenna of thickness λ/60 based on the use of a microstrip patch antenna and two bidimensional metamaterial-based surfaces, the first one acting as a High Impedance Surface (HIS) and the second one acting as a Partially Reflecting Surface (PRS) is designed. This cavity is then optimized for easier fabrication process and loss reduction by the use of only one bidimensionnal composite metamaterial-based surface acting as a PRS. Secondly, another surface presenting a variable phase by the use of a non periodic metamaterial-based metallic strips array is designed for a passive low-profile steering beam antenna application. Finally, a switchable operation frequency cavity by the implementation of varicap diodes is designed and fabricated. All these cavity antennas operate on subwavelength modes, the smallest cavity thickness being of the order of λ/60.

  4. Effects of beam steering in pulsed-wave ultrasound velocity estimation.

    PubMed

    Steinman, Aaron H; Yu, Alfred C H; Johnston, K Wayne; Cobbold, Richard S C

    2005-08-01

    Experimental and computer simulation methods have been used to investigate the significance of beam steering as a potential source of error in pulsed-wave flow velocity estimation. By simulating a typical linear-array transducer system as used for spectral flow estimation, it is shown that beam steering can cause an angle offset resulting in a change in the effective beam-flow angle. This offset primarily depends on the F-number and the nominal steering angle. For example, at an F-number of 3 and a beam-flow angle of 70 degrees , the velocity error changed from -5% to + 5% when the steering angle changed from -20 degrees to + 20 degrees . Much higher errors can occur at higher beam-flow angles, with smaller F-numbers and greater steering. Our experimental study used a clinical ultrasound system, a tissue-mimicking phantom and a pulsatile waveform to determine peak flow velocity errors for various steering and beam-flow angles. These errors were found to be consistent with our simulation results.

  5. Optically-tunable beam steering grating based n azobenzene doped cholesteric liquid crystal.

    PubMed

    Jau, Hung-Chang; Lin, Tsung-Hsien; Fung, Ri-Xin; Huang, San-Yi; Liu, J-H; Fuh, Andy Y-G

    2010-08-02

    This work proposes an optically controllable beam-steering device, fabricated using cholesteric liquid crystals (CLCs) that are doped with azobenzene. The trans-cis photoisomerization of azobenzene changes the pitch of the CLC fingerprint structure and shifts the diffraction angle. The diffraction angle increases when the cell is irradiated with UV light, and restored when it is irradiated with green light. Combining the photoisomerization effect with electrical effect, the CLC beam-steering device provides a steering angle of approximately 19 degrees. The tuning is continuous and could be completed within a few seconds.

  6. Wide-angle, nonmechanical beam steering with high throughput utilizing polarization gratings.

    PubMed

    Kim, Jihwan; Oh, Chulwoo; Serati, Steve; Escuti, Michael J

    2011-06-10

    We introduce and demonstrate a ternary nonmechanical beam steering device based on polarization gratings (PGs). Our beam steering device employs multiple stages consisting of combinations of PGs and wave plates, which allows for a unique three-way (ternary) steering design. Ultrahigh efficiency (∼100%) and polarization sensitive diffraction of individual PGs allow wide steering angles (among three diffracted orders) with extremely high throughput. We report our successful demonstration of the three-stage beam steerer having a 44° field of regard with 1.7° resolution at 1550  nm wavelength. A substantially high throughput of 78%-83% is observed that is mainly limited by electrode absorption and Fresnel losses.

  7. 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.

  8. 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.

  9. Beam steering uncertainty analysis for Risley prisms based on Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Zhang, Hao; Yuan, Yan; Su, Lijuan; Huang, Fengzhen

    2017-01-01

    The Risley-prism system is applied in imaging LADAR to achieve precision directing of laser beams. The image quality of LADAR is affected deeply by the laser beam steering quality of Risley prisms. The ray-tracing method was used to predict the pointing error. The beam steering uncertainty of Risley prisms was investigated through Monte Carlo simulation under the effects of rotation axis jitter and prism rotation error. Case examples were given to elucidate the probability distribution of pointing error. Furthermore, the effect of scan pattern on the beam steering uncertainty was also studied. It is found that the demand for the bearing rotational accuracy of the second prism is much more stringent than that of the first prism. Under the effect of rotation axis jitter, the pointing uncertainty in the field of regard is related to the altitude angle of the emerging beam, but it has no relationship with the azimuth angle. The beam steering uncertainty will be affected by the original phase if the scan pattern is a circle. The proposed method can be used to estimate the beam steering uncertainty of Risley prisms, and the conclusions will be helpful in the design and manufacture of this system.

  10. A new generation of IC based beam steering devices for free-space optical communication

    NASA Astrophysics Data System (ADS)

    Bedi, Vijit

    Free Space Optical (FSO) communication has tremendously advanced within the last decade to meet the ever increasing demand for higher communication bandwidth. Advancement in laser technology since its invention in the 1960's [1] attracted them to be the dominant source in FSO communication modules. The future of FSO systems lay in implementing semiconductor lasers due to their small size, power efficiency and mass fabrication abilities. In the near future, these systems are very likely to be used in space and ground based applications and revolutionary beam steering technologies will be required for distant communications in free-space. The highly directional characteristic inherent to a laser beam challenges and calls for new beam pointing and steering technologies for such type of communication. In this dissertation, research is done on a novel FSO communication device based on semiconductor lasers for high bandwidth communication. The "Fly eye transceiver" is an extremely wide steering bandwidth, completely non-mechanical FSO laser communication device primarily designed to replace traditional mechanical beam steering optical systems. This non-mechanical FSO device possesses a full spherical steering range and a very high tracking bandwidth. Inspired by the evolutionary model of a fly's eye, the full spherical steering range is assured by electronically controlled switching of its sub-eyes. Non mechanical technologies used in the past for beam steering such as acousto-optic Bragg cells, liquid crystal arrays or piezoelectric elements offer the wide steering bandwidth and fast response time, but are limited in their angular steering range. Mechanical gimbals offer a much greater steering range but face a much slower response time or steering bandwidth problem and often require intelligent adaptive controls with bulky driver amplifiers to feed their actuators. As a solution to feed both the fast and full spherical steering, the Fly-eye transceiver is studied as

  11. 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%.

  12. 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.

  13. 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.

  14. Wide Field-of-view and Broadband Terahertz Beam Steering Based on Gap Plasmon Geodesic Antennas

    NASA Astrophysics Data System (ADS)

    Liu, Kaipeng; Guo, Yinghui; Pu, Mingbo; Ma, Xiaoliang; Li, Xiong; Luo, Xiangang

    2017-01-01

    Despite a plethora of applications ranging from wireless communications to sensing and spectroscopy, the current terahertz beam steering technologies suffer from tremendous insert loss, stringent control of electric bias, limited scanning angle, relatively complicated configuration and narrow operation bandwidth, preventing further practical application. We propose and demonstrate a conceptually new approach for terahertz beam steering by virtue of gap plasmon geodesic antennas. By adjusting the geometric dimension of the gap plasmon geodesic antennas, all gap plasmon modes add coherently along a peculiar direction that depends on the geodesic mean surface. Consequently, high directive beams are generated through the antenna, whose direction could be changed within a wide-angle range spanning ±45° by lateral motion of the feed. Furthermore, an assembled antenna structure consisting of four-element geodesic antennas array is proposed for full 360° beam steering, which can operate in a broadband range from 0.8 THz to 1.2 THz.

  15. Wide Field-of-view and Broadband Terahertz Beam Steering Based on Gap Plasmon Geodesic Antennas.

    PubMed

    Liu, Kaipeng; Guo, Yinghui; Pu, Mingbo; Ma, Xiaoliang; Li, Xiong; Luo, Xiangang

    2017-01-30

    Despite a plethora of applications ranging from wireless communications to sensing and spectroscopy, the current terahertz beam steering technologies suffer from tremendous insert loss, stringent control of electric bias, limited scanning angle, relatively complicated configuration and narrow operation bandwidth, preventing further practical application. We propose and demonstrate a conceptually new approach for terahertz beam steering by virtue of gap plasmon geodesic antennas. By adjusting the geometric dimension of the gap plasmon geodesic antennas, all gap plasmon modes add coherently along a peculiar direction that depends on the geodesic mean surface. Consequently, high directive beams are generated through the antenna, whose direction could be changed within a wide-angle range spanning ±45° by lateral motion of the feed. Furthermore, an assembled antenna structure consisting of four-element geodesic antennas array is proposed for full 360° beam steering, which can operate in a broadband range from 0.8 THz to 1.2 THz.

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

    NASA Astrophysics Data System (ADS)

    Rabinovich, William S.; Goetz, Peter G.; Pruessner, Marcel W.; Mahon, Rita; Ferraro, Mike S.; Park, Doe; Fleet, Erin; DePrenger, Michael J.

    2016-11-01

    Many components for free-space optical (FSO) communication systems have shrunken in size over the last decade. However, the steering systems have remained large and power hungry. Nonmechanical beam steering offers a path to reducing the size of these systems. Optical phased arrays can allow integrated beam steering elements. One of the most important aspects of an optical phased array technology is its scalability to a large number of elements. Silicon photonics can potentially offer this scalability using CMOS foundry techniques. A phased array that can steer in two dimensions using the thermo-optic effect is demonstrated. No wavelength tuning of the input laser is needed and the design allows a simple control system with only two inputs. A benchtop FSO link with the phased array in both transmit and receive mode is demonstrated.

  17. Highly integrated optical phased arrays: photonic integrated circuits for optical beam shaping and beam steering

    NASA Astrophysics Data System (ADS)

    Heck, Martijn J. R.

    2016-06-01

    Technologies for efficient generation and fast scanning of narrow free-space laser beams find major applications in three-dimensional (3D) imaging and mapping, like Lidar for remote sensing and navigation, and secure free-space optical communications. The ultimate goal for such a system is to reduce its size, weight, and power consumption, so that it can be mounted on, e.g. drones and autonomous cars. Moreover, beam scanning should ideally be done at video frame rates, something that is beyond the capabilities of current opto-mechanical systems. Photonic integrated circuit (PIC) technology holds the promise of achieving low-cost, compact, robust and energy-efficient complex optical systems. PICs integrate, for example, lasers, modulators, detectors, and filters on a single piece of semiconductor, typically silicon or indium phosphide, much like electronic integrated circuits. This technology is maturing fast, driven by high-bandwidth communications applications, and mature fabrication facilities. State-of-the-art commercial PICs integrate hundreds of elements, and the integration of thousands of elements has been shown in the laboratory. Over the last few years, there has been a considerable research effort to integrate beam steering systems on a PIC, and various beam steering demonstrators based on optical phased arrays have been realized. Arrays of up to thousands of coherent emitters, including their phase and amplitude control, have been integrated, and various applications have been explored. In this review paper, I will present an overview of the state of the art of this technology and its opportunities, illustrated by recent breakthroughs.

  18. Highly integrated optical phased arrays: photonic integrated circuits for optical beam shaping and beam steering

    NASA Astrophysics Data System (ADS)

    Heck, Martijn J. R.

    2017-01-01

    Technologies for efficient generation and fast scanning of narrow free-space laser beams find major applications in three-dimensional (3D) imaging and mapping, like Lidar for remote sensing and navigation, and secure free-space optical communications. The ultimate goal for such a system is to reduce its size, weight, and power consumption, so that it can be mounted on, e.g. drones and autonomous cars. Moreover, beam scanning should ideally be done at video frame rates, something that is beyond the capabilities of current opto-mechanical systems. Photonic integrated circuit (PIC) technology holds the promise of achieving low-cost, compact, robust and energy-efficient complex optical systems. PICs integrate, for example, lasers, modulators, detectors, and filters on a single piece of semiconductor, typically silicon or indium phosphide, much like electronic integrated circuits. This technology is maturing fast, driven by high-bandwidth communications applications, and mature fabrication facilities. State-of-the-art commercial PICs integrate hundreds of elements, and the integration of thousands of elements has been shown in the laboratory. Over the last few years, there has been a considerable research effort to integrate beam steering systems on a PIC, and various beam steering demonstrators based on optical phased arrays have been realized. Arrays of up to thousands of coherent emitters, including their phase and amplitude control, have been integrated, and various applications have been explored. In this review paper, I will present an overview of the state of the art of this technology and its opportunities, illustrated by recent breakthroughs.

  19. Theoretical aspects of the agile mirror

    NASA Astrophysics Data System (ADS)

    Manheimer, Wallace M.; Fernsler, Richard

    1994-01-01

    A planar plasma mirror which can be oriented electronically could have the capability of providing electronic steering of a microwave beam in a radar or electronic warfare system. This system is denoted the agile mirror. A recent experiment has demonstrated such a planar plasma and the associated microwave reflection. This plasma was produced by a hollow cathode glow discharge, where the hollow cathode was a grooved metallic trench in a Lucite plate. Various theoretical aspects of this configuration of an agile mirror are examined here.

  20. 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.

  1. 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°.

  2. 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.

  3. 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.

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

    DOE PAGES

    Moore, Michael H.; Waidyawansa, Buddhini P.; Covrig, Silviu; ...

    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.

  5. Enhanced beam-steering-based diagonal beamforming algorithm for binaural hearing support devices.

    PubMed

    Lee, Jun Chang; Nam, Kyoung Won; Cho, Kyeongwon; Lee, Sangmin; Kim, Dongwook; Hong, Sung Hwa; Jang, Dong Pyo; Kim, In Young

    2014-07-01

    In order to improve speech intelligibility for hearing-impaired people in various listening situations, it is necessary to diversify the possible focusing directions of a beamformer. In a previous report, the concept of binaural beam-steering that can focus a beamformer in diagonal directions was applied to a binaural hearing aid; however, in the previously proposed protocol, the effective frequency range for consistent diagonal beam-steering was limited to the 200-750 Hz range, which is far narrower than that of normal speech signals (200-4000 Hz). In this study, we proposed a modified binaural diagonal beam-steering technique that can reduce the focusing-direction deviations at high input frequencies up to 4000 Hz by introducing a new correction factor to the original protocol that can reduce the differences in gradient between the signal and the noise components at frequencies up to 4000 Hz. In simulation tests, the focusing effect of the proposed algorithm was more consistent than conventional algorithms. The deviations between the target and the focusing directions were reduced 27% in the left device and 6% in the right device with 45° steering at a 4000 Hz input signal, and were reduced 3% in the left device and 25% in the right device with 135° steering. On the basis of the experimental results, we believe that the proposed algorithm has the potential to help hearing-impaired people in various listening situations.

  6. Analysis of beam steering tolerances and divergence for various long range FSO communication links

    NASA Astrophysics Data System (ADS)

    Harris, Alan; Sluss, James J., Jr.; Refai, Hazem H.; LoPresti, Peter G.

    2005-06-01

    Through the use of recent technological developments, it is now feasible to establish free-space optical (FSO) communication links over ultra-long distances. Recent research has shown that FSO systems could be deployed to establish high-rate data links to deep space. This study analyzes beam steering tolerances, beam divergence, and geometric loss for different distance ranges of interest for FSO communication links based on a mechanical gimbaled beam steering mechanism. The tolerance, divergence and geometric loss calculations are performed to evaluate the feasibility of establishing FSO links between the Earth and satellites, the Earth and aircraft, aircraft and satellites, the Earth and moon, the Earth and Mars, and the Earth and the edge of the solar system. The analysis and calculations performed take into consideration the availability of new technology such as low noise photon-counting detectors and fiber lasers and amplifiers. The beam steering tolerance and divergence calculations provide beneficial information for determining the extent to which future FSO systems could be deployed for both commercial, military and space exploration applications. Recommendations on the suitability of an FSO communication link for various applications are then made based on the beam steering tolerance and divergence calculations.

  7. 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.

  8. Characterizing the beam steering and distortion of Gaussian and Bessel beams focused in tissues with microscopic heterogeneities.

    PubMed

    Chen, Ye; Liu, Jonathan T C

    2015-04-01

    Bessel beams have recently been investigated as a means of improving deep-tissue microscopy in highly scattering and heterogeneous media. It has been suggested that the long depth-of-field and self-reconstructing property of a Bessel beam enables an increased penetration depth of the focused beam in tissues compared to a conventional Gaussian beam. However, a study is needed to better quantify the magnitude of the beam steering as well as the distortion of focused Gaussian and Bessel beams in tissues with microscopic heterogeneities. Here, we have developed an imaging method and quantitative metrics to evaluate the motion and distortion of low-numerical-aperture (NA) Gaussian and Bessel beams focused in water, heterogeneous phantoms, and fresh mouse esophagus tissues. Our results indicate that low-NA Bessel beams exhibit reduced beam-steering artifacts and distortions compared to Gaussian beams, and are therefore potentially useful for microscopy applications in which pointing accuracy and beam quality are critical, such as dual-axis confocal (DAC) microscopy.

  9. Normal and shear strain imaging using 2D deformation tracking on beam steered linear array datasets

    PubMed Central

    Xu, Haiyan; Varghese, Tomy

    2013-01-01

    Purpose: Previous publications have reported on the use of one-dimensional cross-correlation analysis with beam-steered echo signals. However, this approach fails to accurately track displacements at larger depths (>4.5 cm) due to lower signal-to-noise. In this paper, the authors present the use of adaptive parallelogram shaped two-dimensional processing blocks for deformation tracking. Methods: Beam-steered datasets were acquired using a VFX 9L4 linear array transducer operated at a 6 MHz center frequency for steered angles from −15 to 15° in increments of 1°, on both uniformly elastic and single-inclusion tissue-mimicking phantoms. Echo signals were acquired to a depth of 65 mm with the focus set at 40 mm corresponding to the center of phantom. Estimated angular displacements along and perpendicular to the beam direction are used to compute axial and lateral displacement vectors using a least-squares approach. Normal and shear strain tensor component are then estimated based on these displacement vectors. Results: Their results demonstrate that parallelogram shaped two-dimensional deformation tracking significantly improves spatial resolution (factor of 7.79 along the beam direction), signal-to-noise (5 dB improvement), and contrast-to-noise (8–14 dB improvement) associated with strain imaging using beam steering on linear array transducers. Conclusions: Parallelogram shaped two-dimensional deformation tracking is demonstrated in beam-steered radiofrequency data, enabling its use in the estimation of normal and shear strain components. PMID:23298118

  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. One mirror beam steering: determination of steering mirror parameters from image pointing direction

    NASA Astrophysics Data System (ADS)

    Andersen, Torben B.; Granger, Zachary A.

    2016-09-01

    Mathematical models are used to establish the exact path of a beam reflected by a plane mirror in terms of the mirror geometry descriptors. In particular, the mirror geometry descriptors (tilt angles) are determined as functions of the beam path in image space. This is also useful for determining scan patterns when the mirror is used as a scanning device. These formulations are readily adaptable to commercially available ray tracing programs.

  12. High power transcranial beam steering for ultrasonic brain therapy.

    PubMed

    Pernot, M; Aubry, J F; Tanter, M; Thomas, J L; Fink, M

    2003-08-21

    A sparse phased array is specially designed for non-invasive ultrasound transskull brain therapy. The array is made of 200 single elements corresponding to a new generation of high power transducers developed in collaboration with Imasonic (Besançon, France). Each element has a surface of 0.5 cm2 and works at 0.9 MHz central frequency with a maximum 20 W cm(-2) intensity on the transducer surface. In order to optimize the steering capabilities of the array, several transducer distributions on a spherical surface are simulated: hexagonal, annular and quasi-random distributions. Using a quasi-random distribution significantly reduces the grating lobes. Furthermore, the simulations show the capability of the quasi-random array to electronically move the focal spot in the vicinity of the geometrical focus (up to +/- 15 mm). Based on the simulation study, the array is constructed and tested. The skull aberrations are corrected by using a time reversal mirror with amplitude correction achieved thanks to an implantable hydrophone, and a sharp focus is obtained through a human skull. Several lesions are induced in fresh liver and brain samples through human skulls, demonstrating the accuracy and the steering capabilities of the system.

  13. Beam-steering and jammer-nulling photorefractive phased-array radar processor

    NASA Astrophysics Data System (ADS)

    Sarto, Anthony W.; Weverka, Robert T.; Wagner, Kelvin H.

    1994-06-01

    We are developing a class of optical phased-array-radar processors which use the large number of degrees-of-freedom available in 3D photorefractive volume holograms to time integrate the adaptive weights to perform beam-steering and jammer-cancellation signal-processing tasks for very large phased-array antennas. We have experimentally demonstrated independently the two primary subsystems of the beam-steering and jammer-nulling phased-array radar processor, the beam-forming subsystem and the jammer-nulling subsystem, as well as simultaneous main beam formation and jammer suppression in the combined processor. The beam-steering subsystem calculates the angle of arrival of a desired signal of interest and steers the antenna pattern in the direction of this desired signal by forming a dynamic holographic grating proportional to the correlation between the incoming signal of interest from the antenna array and the temporal waveform of the desired signal. This grating is formed by repetitively applying the temporal waveform of the desired signal to a single acousto-optic Bragg cell and allowing the diffracted component from the Bragg cell to interfere with an optical mapping of the received phased-array antenna signal at a photorefractive crystal. The diffracted component from this grating is the antenna output modified by an array function pointed towards the desired signal of interest. This beam-steering task is performed with the only a priori information being that of the knowledge of a temporal waveform that correlates well with the desired signal and that the delay of the desired signal remains within the time aperture of the Bragg cell. The jammer-nulling subsystem computes the angles-of- arrival of multiple interfering narrowband radar jammers and adaptively steers nulls in the antenna pattern in order to extinguish the jammers by implementing a modified LMS algorithm in the optical domain. This task is performed in a second photorefractive crystal where

  14. Improved beam steering efficiency of large deflection angle for periodic grating

    NASA Astrophysics Data System (ADS)

    Zhou, Jian-hua; Kong, Ling-jiang; Xiao, Feng; Zhuo, Jing-yi; Yang, Xiao-bo

    2013-08-01

    The limited quantization digit of voltage and the effect of fringing field between adjacent electrodes (phased-array controlling units) limit the deflection efficiency when a Liquid-Crystal Phased Array (LCPA) is used for beam steering. In this paper, an optimization algorithm named pattern search is proposed to improve the diffraction efficiency. This algorithm directly optimizes the step phase slope to obtain high diffraction efficiency, rather than discussing the complex relationship between the diffraction efficiency and various influence factors. Besides, other optimization algorithms based on phase retrieval, such as GS, need the entire energy distribution; however, it is hard to obtain in practical. Our algorithm need only the energy of the target diffraction point and it can be easily realized. Firstly, we construct the model for beam steering, and point out that the deformation of the phase slope by influence factors is the reason why conventional method can not realize high diffraction efficiency. Secondly, we construct an optimization model for the issues and apply the pattern search algorithm to optimize the diffraction efficiency. The simulation results show high performance of our algorithm comparing with the conventional steering method. Finally, a set of beam steering experiments were performed with a one-dimensional LCPA being set both according to the un-optimized and the optimized recipe, and the results were in very good agreement with the theoretical predictions. We show that the deflection efficiency can be drastically improved.

  15. 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.

  16. GMTIFS: the adaptive optics beam steering mirror for the GMT integral-field spectrograph

    NASA Astrophysics Data System (ADS)

    Davies, J.; Bloxham, G.; Boz, R.; Bundy, D.; Espeland, B.; Fordham, B.; Hart, J.; Herrald, N.; Nielsen, J.; Sharp, R.; Vaccarella, A.; Vest, C.; Young, P. J.

    2016-07-01

    To achieve the high adaptive optics sky coverage necessary to allow the GMT Integral-Field Spectrograph (GMTIFS) to access key scientific targets, the on-instrument adaptive-optics wavefront-sensing (OIWFS) system must patrol the full 180 arcsecond diameter guide field passed to the instrument. The OIWFS uses a diffraction limited guide star as the fundamental pointing reference for the instrument. During an observation the offset between the science target and the guide star will change due to sources such as flexure, differential refraction and non-sidereal tracking rates. GMTIFS uses a beam steering mirror to set the initial offset between science target and guide star and also to correct for changes in offset. In order to reduce image motion from beam steering errors to those comparable to the AO system in the most stringent case, the beam steering mirror is set a requirement of less than 1 milliarcsecond RMS. This corresponds to a dynamic range for both actuators and sensors of better than 1/180,000. The GMTIFS beam steering mirror uses piezo-walk actuators and a combination of eddy current sensors and interferometric sensors to achieve this dynamic range and control. While the sensors are rated for cryogenic operation, the actuators are not. We report on the results of prototype testing of single actuators, with the sensors, on the bench and in a cryogenic environment. Specific failures of the system are explained and suspected reasons for them. A modified test jig is used to investigate the option of heating the actuator and we report the improved results. In addition to individual component testing, we built and tested a complete beam steering mirror assembly. Testing was conducted with a point source microscope, however controlling environmental conditions to less than 1 micron was challenging. The assembly testing investigated acquisition accuracy and if there was any un-sensed hysteresis in the system. Finally we present the revised beam steering mirror

  17. Wide Field-of-view and Broadband Terahertz Beam Steering Based on Gap Plasmon Geodesic Antennas

    PubMed Central

    Liu, Kaipeng; Guo, Yinghui; Pu, Mingbo; Ma, Xiaoliang; Li, Xiong; Luo, Xiangang

    2017-01-01

    Despite a plethora of applications ranging from wireless communications to sensing and spectroscopy, the current terahertz beam steering technologies suffer from tremendous insert loss, stringent control of electric bias, limited scanning angle, relatively complicated configuration and narrow operation bandwidth, preventing further practical application. We propose and demonstrate a conceptually new approach for terahertz beam steering by virtue of gap plasmon geodesic antennas. By adjusting the geometric dimension of the gap plasmon geodesic antennas, all gap plasmon modes add coherently along a peculiar direction that depends on the geodesic mean surface. Consequently, high directive beams are generated through the antenna, whose direction could be changed within a wide-angle range spanning ±45° by lateral motion of the feed. Furthermore, an assembled antenna structure consisting of four-element geodesic antennas array is proposed for full 360° beam steering, which can operate in a broadband range from 0.8 THz to 1.2 THz. PMID:28134324

  18. 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.

  19. MEMS-based diffractive optical-beam-steering technology

    NASA Astrophysics Data System (ADS)

    Winick, David A.; Duewer, Bruce E.; Chaudhury, Som; Wilson, John M.; Tucker, John; Eksi, Umut; Franzon, Paul D.

    1998-03-01

    This paper presents some results from phase-1 research into developing a beam steerer based on micro-mechanical diffractive elements. The position of these elements is electrostatically controlled, to allow dynamic programming of a 2D phase function. Feasibility prototypes were constructed in the MUMPs polysilicon surface micromachine process.

  20. Beam steering and routing in quadratic nonlinear media

    SciTech Connect

    Aceves, A.B.; Santos, M.C.; Torner, L.

    1997-04-01

    We show how the spatial phase modulation of weak second-harmonic signals controls the overall direction of propagation of spatial solitons in quadratic nonlinear media. We investigate numerically such a process and discuss its applications to all-optical beam routing. 5 refs., 3 figs.

  1. 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

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

    PubMed

    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

    2015-06-08

    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.

  3. 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.

  4. Symmetric-pair antennas for beam steering, direction finding or isotropic-reception gain

    NASA Astrophysics Data System (ADS)

    Benjamin, R.; Titze, W.; Brennan, P. V.; Griffiths, H. D.

    1991-08-01

    A novel type of phased array is described which seems particularly attractive in direction finding and adaptive beam steering applications, and allows considerable simplification in the necessary signal processing. A variant of the technique also permits gain with isotropic coverage for reception. The principles of the technique are outlined, along with a discussion of several possible array configurations for use with direction finding, communications and spectrum monitoring. Experimental results are presented to confirm the predicted behavior of the array.

  5. 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).

  6. 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.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    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.

  9. Beam Steering of Electrically Segmented Piezo-Ceramic Ultrasonic Transducers Using Normal Mode Coupling.

    DTIC Science & Technology

    2014-09-26

    law the angle of the radiated beam can be written as: C sine = w S where Cw is the speed of sound in the water and Cs is the shear velocity in the...PAGE RED MSTUCTION S 3370O3K COMPL.ETFING FORM . I. REPORT NUMD5R. GOVT ACCESSION NO. - ECIPIENT’S CATALOG NUMBER r" SO REFERENCE 84-38 4. TITLE (and...Subile) S . TYPE OF REPORT A PERIOD COVERED BEAM STEERING OF ELECTRICALLY SEGMENTED PIEZO-CERAMIC ULTRASONIC TRANSDUCERS USING Summary ,.-41

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  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.

  17. Analysis of beam steering by diffraction and the scattering of light by turbulence

    NASA Astrophysics Data System (ADS)

    Tsui, Jing M.

    This thesis addresses two problems. The first is the performance of non-mechanical beam steering devices based on diffractive optics, and the second is the problem of the scattering of light by turbulence. Two beam steering devices namely holographic optical elements and optical phased arrays are analyzed. Of particular interest are the wavelength selectivity of the uniform volume holographic grating and the impact of dispersion on the spatial and temporal fidelity of an optically transmitted communication signal through both beamsteering devices. Longitudinal refractive index modulation (apodization) in photosensitive glass is used to improve sidelobe. Theoretical methods are developed to model both devices. For uniform grating, it is shown that the temporal dispersion due to the diffraction increase with beam diameter yielding a higher power penalty for large diffraction angles and aperture sizes. For an optical phased array, it is shown the power penalty increase as the diffraction angles and diameters increase. In addition, the scattering of light in turbulent medium is investigated. Of particular interest is to determine region of validity of the Born approximation which is used to compute the scattering field. Pade approximants are used to analyze the propagation through a media having strong turbulent intensity. It is shown that the region of convergence of Born approximation increases as the outer scale of the turbulence decreases. In the case of the strong turbulence, the Born approximation does not capture the correct angular distribution of the scattering intensity.

  18. Fabrication of LiNbO3-As2S3 waveguides for beam steering applications

    NASA Astrophysics Data System (ADS)

    Macik, Dwayne D.; Madsen, Christi K.

    2016-09-01

    A hybrid annealed proton exchange (APE) waveguide with a vertically integrated arsenic trisulfide (As2S3) waveguide on a lithium niobate (LiNbO3) substrate is used to create an optical phased array (OPA) that allows for the non-mechanical steering of 1550 nm light on an integrated optic platform. The high electro-optic coefficient of the x-cut y-propagating LiNbO3 (r33 = 30.8 pm/V) is utilized by electrode structures fabricated on the LiNbO3 substrate to create a low-power, lowloss beam steering with high-speed bandwidths, capable of 10 GHz and larger as demonstrated by commercial LiNbO3 modulators. The As2S3 waveguide is introduced because of its high refractive index, which leads to a highly confined optical mode. Design and fabrication are presented for a large full width steering angle of 34°, representing an order of magnitude improvement over low-confinement, diffused LiNbO3 waveguides and two orders of magnitude improvement over other reported LiNbO3 OPAs.

  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.

  20. System for demonstrating arbitrary multi-spot beam steering from spatial light modulators.

    PubMed

    Xun, Xiaodong; Chang, Xiaoguang; Cohn, Robert

    2004-01-26

    A graphical user interface is used to program sequences of analog phase patterns onto a 512 x 512 pixel, electrically-addressed spatial light modulator (SLM). Hand sketches made with a digital pen are used to prescribe the footprints, velocities and trajectories of multiple, independently-controlled diffracted spots. The interface is intended to demonstrate to potential end-users, who are not knowledgeable about diffractive optical design, to what degree SLM's may be considered to produce arbitrary multi-spot beam steering. Using the interface, scanning sequences are created, programmed, run through, and diffracted from a SLM that simultaneously scans multiple patterns on distinct trajectories.

  1. All-optical steering of laser-wakefield-accelerated electron beams.

    PubMed

    Popp, A; Vieira, J; Osterhoff, J; Major, Zs; Hörlein, R; Fuchs, M; Weingartner, R; Rowlands-Rees, T P; Marti, M; Fonseca, R A; Martins, S F; Silva, L O; Hooker, S M; Krausz, F; Grüner, F; Karsch, S

    2010-11-19

    We investigate the influence of a tilted laser-pulse-intensity front on laser-wakefield acceleration. Such asymmetric light pulses may be exploited to obtain control over the electron-bunch-pointing direction and in our case allowed for reproducible electron-beam steering in an all-optical way within an 8 mrad opening window with respect to the initial laser axis. We also discovered evidence of collective electron-betatron oscillations due to off-axis electron injection into the wakefield induced by a pulse-front tilt. These findings are supported by 3D particle-in-cell simulations.

  2. 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.

  3. Directive metamaterial-based subwavelength resonant cavity antennas - Applications for beam steering

    NASA Astrophysics Data System (ADS)

    Ourir, Abdelwaheb; Burokur, Shah Nawaz; Yahiaoui, Riad; de Lustrac, André

    2009-06-01

    This article presents the use of composite resonant metamaterials for the design of highly directive subwavelength cavity antennas. These metamaterials, composed of planar metallic patterns periodically organized on dielectric substrates, exhibit frequency dispersive phase characteristics. Different models of metamaterial-based surfaces (metasurfaces), introducing a zero degree reflection phase shift to incident waves, are firstly studied where the bandwidth and operation frequency are predicted. These surfaces are then applied in a resonant Fabry-Perot type cavity and a ray optics analysis is used to design different models of ultra-compact high-gain microstrip printed antennas. Another surface presenting a variable reflection phase by the use of a non-periodic metamaterial-based metallic strips array is designed for a passive low-profile steering beam antenna application. Finally, the incorporation of active electronic components on the metasurfaces, allowing an electronic control of the phase responses, is applied to an operation frequency reconfigurable cavity and a beam steering cavity. All these cavity antennas operate on subwavelength modes, the smallest cavity thickness being of the order of λ/60. To cite this article: A. Ourir et al., C. R. Physique 10 (2009).

  4. 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.

  5. Enhanced needle localization in ultrasound using beam steering and learning-based segmentation.

    PubMed

    Hatt, Charles R; Ng, Gary; Parthasarathy, Vijay

    2015-04-01

    Segmentation of needles in ultrasound images remains a challenging problem. In this paper, we introduce a machine learning-based method for needle segmentation in 2D beam-steered ultrasound images. We used a statistical boosting approach to train a pixel-wise classifier for needle segmentation. The Radon transform was then used to find the needle position and orientation from the segmented image. We validated our method with data from ex vivo specimens and clinical nerve block procedures, and compared the results to those obtained using previously reported needle segmentation methods. Results show improved localization success and accuracy using the proposed method. For the ex vivo datasets, assuming that the needle orientation was known a priori, the needle was successfully localized in 86.2% of the images, with a mean targeting error of 0.48mm. The robustness of the proposed method to a lack of a priori knowledge of needle orientation was also demonstrated. For the clinical datasets, assuming that the needle orientation was closely aligned with the beam steering angle selected by the physician, the needle was successfully localized in 99.8% of the images, with a mean targeting error 0.19mm. These results indicate that the learning-based segmentation method may allow for increased targeting accuracy and enhanced visualization during ultrasound-guided needle procedures.

  6. 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.

  7. The adaptive optics beam steering mirror for the GMT Integral-Field Spectrograph, GMTIFS

    NASA Astrophysics Data System (ADS)

    Sharp, R.; Boz, R.; Hart, J.; Bloxham, G.; Bundy, D.; Davis, J.; McGregor, P. J.; Nielson, J.; Vest, C.; Young, P. J.

    2014-07-01

    To achieve the high adaptive optics sky coverage necessary to allow the GMT Integral-Field Spectrograph to access key scientific targets, the on-instrument adaptive-optics wavefront-sensing system must patrol the full 180 arcsecond diameter guide field passed to the instrument. Starlight must be held stationary on the wavefront sensor (accounting for flexure, differential refraction and non-sidereal tracking rates) to ~ 1 milliarcsecond to provide the stable position reference signal for deep AO observations and avoid introducing image blur. Hence a tight tolerance of 1/180,000 is placed on the positioning and encoding accuracy for the cryogenic On-Instrument Wave-Front Sensor feed. GMTIFS will achieve this requirement using a beam-steering mirror system as an optical relay for starlight from across the accessible guide field. The system avoids hysteresis and backlash by eliminating friction and avoiding gearing while maintaining high setting speed and accuracy with a precision feedback loop. Here we present the design of the relay system and the technical solution deployed to meet the challenging specifications for drive rate, accuracy and positional encoding of the beam-steering system.

  8. Plasmonic phased array feeder enabling ultra-fast beam steering at millimeter waves.

    PubMed

    Bonjour, R; Burla, M; Abrecht, F C; Welschen, S; Hoessbacher, C; Heni, W; Gebrewold, S A; Baeuerle, B; Josten, A; Salamin, Y; Haffner, C; Johnston, P V; Elder, D L; Leuchtmann, P; Hillerkuss, D; Fedoryshyn, Y; Dalton, L R; Hafner, C; Leuthold, J

    2016-10-31

    In this paper, we demonstrate an integrated microwave phoneeded for beamtonics phased array antenna feeder at 60 GHz with a record-low footprint. Our design is based on ultra-compact plasmonic phase modulators (active area <2.5µm2) that not only provide small size but also ultra-fast tuning speed. In our design, the integrated circuit footprint is in fact only limited by the contact pads of the electrodes and by the optical feeding waveguides. Using the high speed of the plasmonic modulators, we demonstrate beam steering with less than 1 ns reconfiguration time, i.e. the beam direction is reconfigured in-between 1 GBd transmitted symbols.

  9. Beam steering experiment with two cascaded ferroelectric liquid-crystal spatial light modulators.

    PubMed

    Engström, David; Hård, Sverker; Rudquist, Per; Dhavé, Koen; Matuszczyk, Tomasz; Skeren, Marek; Löfving, Björn

    2004-03-01

    The design, construction, and evaluation of a laser beam steerer that uses two binary ferroelectric liquid-crystal (FLC) spatial light modulators (SLMs) operated in conjunction are presented. The system is characterized by having few components and is in principle lossless. Experimentally, a throughput of approximately 20% was achieved. The simple system design was achieved because of the high tilt angle FLC material used in the SLMs, which were specifically designed and manufactured for this study. By coherently imaging the first SLM onto the second SLM, pixel by pixel, we obtained an effective four-level phase structure with a phase step of 90 degrees. An appropriate alignment procedure is presented. The beam steering performance of the system is reported and analyzed.

  10. SU-E-T-191: Commissioning and Dosimetric Characteristics of Elekta Agility for Total Skin Electron Beam (TSEB) Therapy

    SciTech Connect

    Sayler, E; Charpentier, P; Micaily, B; Miyamoto, C; Li, S

    2015-06-15

    Purpose The purpose of this work is to publish beam data from Elekta Synergy(R) linear accelerators with Agility(TM) MLC for total skin electron beam (TSEB) therapy using the HDRE1 (High Dose Rate Electron 6MeV) energy. Method & Materials The optimal gantry angles for TSEB were determined using ion chamber measurements along a vertical profile at 450cm SSD. After gantry angles were chosen, field uniformity was measured over the entire treatment area. Uniformity was measured with and without the patient support device, allowing the dosimetric effect of the support device to be determined. Beam output and PDD were measured at the calibration point (450cm SSD) for a dual beam using a parallel plate chamber in solid water. These measurements were repeated with the chamber and phantom rotated about the patient isocenter at various angles, in order to measure the contribution from oblique beams. This technique provides a precise measurement of the treatment skin dose (TSD). Lastly, ion chamber measurements were verified by film and diodes. Results The optimal gantry angle for 450 cm SSD was determined to be 90±16°. This achieved uniformity better than 96% on the vertical axis, and 92% along the horizontal axis. HDRE1 was calibrated to deliver 10 cGy/MU at standard geometry (100 cm SSD, 1.2 cm depth). Thus at TSEB geometry (450 cm SSD, 0.1 cm depth) the output of the AP dual field was measured to be 0.35 cGy/MU. The TSD of a 20 cm radius cylinder for six (equally, 60° spaced) dual fields was measured to be 1.19 cGy/MU. Percent Depth Dose data for the AP dual field and TSD are shown in Figure 2. Conclusion This paper provides a modern procedure for commissioning TSEB therapy on a linear accelerator, and clinical beam data for the Elekta Synergy(R) with Agility(TM) MLC.

  11. Beam steering using optical parametric amplification in Kerr medium: a space-time analogy of parametric slow-light.

    PubMed

    Fanjoux, Gil; Lantz, Eric; Michaud, Jérémy; Sylvestre, Thibaut

    2012-11-19

    In a way analogous to a light pulse that can be optically delayed via slow light propagation in Kerr-type nonlinear media, we theoretically demonstrate that beam steering and spatial walk-off compensation can be achieved in noncollinear optical parametric amplification. We identify this effect as a result of the quadratic phase shift induced by parametric amplification that leads to the cancellation of the spatial walk-off and collinear propagation of all beams though they have different wavevectors. Experimental evidence is reported of a soliton array steering in a Kerr slab waveguide.

  12. 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.

  13. 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

  14. Towards doubling solar harvests using wide-angle, broad-band microfluidic beam steering arrays.

    PubMed

    DiDomenico, Leo D

    2015-11-30

    This paper introduces Microfluidic Beam Steering (MBS), which is a new technique for electronically steering light having multiple octaves of bandwidth, any polarization state and incidence from any direction of the sky without significant restrictions due to physical area, optical loss and power handling capacity. It is based on optical elements comprising both transparent solids and electronically controllable fluids to control Total Internal Reflection (TIR), refraction and/or diffraction from micro-structured surfaces within a transparent solid. A TIR-based MBS is discussed in the context of solar energy and its potential to significantly increase annual energy harvests from solar arrays situated on fixed areas like roofs. The advantages and challenges associated with analog and digital MBS systems are discussed and early-stage MBS hardware is demonstrated. Finally, an analytic model of sun-tracking is provided to formally establish the potential for MBS to increase annual solar energy harvests by approximately 45% more than conventional 0-Degree Of Freedom (0-DOF) solar arrays, 62% more than 1-DOF arrays and 233% more than 2-DOF arrays, all at 20% atmospheric aerosol scattering.

  15. 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.

  16. 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.

  17. 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

    2016-04-04

    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.

  18. Agile Mythbusting

    DTIC Science & Technology

    2015-01-01

    does not fit all Scrum : The most adopted Agile method Scaling Agile Methods: Going beyond the team level methods Challenges to Agile Adoption: What’s...Arsenal Lapham, Wrubel Jan 2015 © 2015 Carnegie Mellon University. Myth: You Must Choose Agile or Waterfall – you can’t do both What about “water- scrum ...used in multiple environments, including DoD programs.1 1Start with “Agile EVM in Scrum Projects” from AGILE 2006 to get started learning about Agile

  19. SU-E-T-645: Qualification of a 2D Ionization Chamber Array for Beam Steering and Profile Measurement

    SciTech Connect

    Gao, S; Balter, P; Rose, M; Simon, W

    2015-06-15

    Purpose: Establish a procedure for beam steering and profile measurement using a 2D ionization chamber array and show equivalence to a water scanning system. Methods: Multiple photon beams (30×30cm{sup 2} field) and electron beams (25×25cm{sup 2} cone) were steered in the radial and transverse directions using Sun Nuclear’s IC PROFILER (ICP). Solid water was added during steering to ensure measurements were beyond the buildup region. With steering complete, servos were zeroed and enabled. Photon profiles were collected in a 30×30cm{sup 2} field at dmax and 2.9 cm depth for flattened and FFF beams respectively. Electron profiles were collected with a 25×25cm{sup 2} cone and effective depth (solid water + 0.9 cm intrinsic buildup) as follows: 0.9 cm (6e), 1.9 cm (9e), 2.9 cm (12e, 16e, 20e). Profiles of the same energy, field size and depth were measured in water with Sun Nuclear’s 3D SCANNER (3DS). Profiles were re-measured using the ICP after the in-water scans. Profiles measured using the ICP and 3DS were compared by (a) examining the differences in Varian’s “Point Difference Symmetry” metric, (b) visual inspection of the overlaid profile shapes and (c) calculation of point-by-point differences. Results: Comparing ICP measurements before and after water scanning showed very good agreement indicating good stability of the linac and measurement system. Comparing ICP Measurements to water phantom measurements using Varian’s symmetry metric showed agreement within 0.5% for all beams. The average magnitude of the agreement was within 0.2%. Comparing ICP Measurements to water phantom measurements using point-by-point difference showed agreement within 0.5% inside of 80% area of the field width. Conclusion: Profile agreement to within 0.5% was observed between ICP and 3DS after steering multiple energies with the ICP. This indicates that the ICP may be used for steering electron beams, and both flattened and FFF photon beams. Song Gao: Sun Nuclear

  20. Optical properties of beam-steering elements utilizing volume holographic gratings

    NASA Astrophysics Data System (ADS)

    Butler, James Jay

    2000-06-01

    An optical beam steering element is a device that is used to control the direction in which a beam of light travels. We have investigated the optical properties of two classes of optical beam steering elements. The first type utilized the polarization dependence of the diffraction efficiency of volume holographic gratings. The second type utilized the fact that the diffraction efficiency of holograms imbibed with a nematic liquid crystal can be controlled by the application of an electric field. In both cases, elements with excellent switching contrasts were fabricated for operation in the visible and near infrared wavelength range including the commonly used telecommunications wavelength of 1.3μm. The holographic recording material that we have used is Polaroid Corporation's DMP-128 photopolymer. This material is porous after exposure and processing, a feature useful in two ways for this work. First, volume gratings with very large refractive index modulations, on the order of 0.2, can be fabricated using this material. Secondly, the pores can be filled with a nematic liquid crystal, resulting in electrically-switchable gratings. In our analysis of polarization-sensitive gratings we have employed several coupled wave theories, each with a different set of approximations. We have found that rigorous coupled wave theory must be used in predicting the diffractive properties of highly modulated volume gratings, where the effects of higher diffraction orders and form birefringence become important. In our analysis of the optical properties of electrically-switchable liquid crystal composite holograms, we have employed a theoretical analysis that treats the birefringent nature of the gratings. The results of Kogelnik theory that neglects the grating anisotropy, a two-wave theory that treats anisotropy, and a formulation of rigorous coupled wave theory that includes anisotropy were compared. We found it was necessary to include the effects of optical anisotropy to

  1. 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

  2. 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

    2014-11-03

    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.

  3. 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.

  4. High power, fast, microwave components based on beam generated plasmas

    NASA Astrophysics Data System (ADS)

    Manheimer, W. M.; Fernsler, R. F.; Gitlin, M. S.

    1998-10-01

    It is shown that the agile mirror plasma, under development as a device to simply and cheaply give electronic steering to microwave beams, also has application as a fast, electronically controlled, high power reflector, or phase shifter. In a radar system, this can lead to such applications as pulse to pulse polarization agility and electronic control of antenna gain, as well as to innovative approaches to high power millimeter wave circulators. The basic theory of the enhanced glow plasma is also developed.

  5. Electronic beam steering used with a toroidal HIFU transducer substantially increases the coagulated volume.

    PubMed

    Vincenot, Jeremy; Melodelima, David; Chavrier, Françoise; Vignot, Alexandre; Kocot, Anthony; Chapelon, Jean-Yves

    2013-07-01

    Treatment with high-intensity focused ultrasound is well established but requires extended treatment time. A device composed of 256 elements arranged on a toroidal transducer was developed to increase the coagulated volume. When all the elements are working in phase for 40 s, a volume of 6-8 cm(3) can be ablated. However, the mechanical juxtaposition of single lesions is still necessary for treating one tumor with a diameter of 2 cm. The objective of this study was to combine this toroidal transducer geometry with electronic beam steering to ablate tumors with adequate normal tissue margins and without any mechanical displacement of the high-intensity focused ultrasound device. In vitro tests demonstrated that the coagulated volume obtained from 130 s of total exposure has an average diameter of 41.4 ± 4.0 mm and an average length of 53.3 ± 6.1 mm. This single lesion can be used to treat various size of metastasis, located at depths in the liver ranging 5-45 mm.

  6. Optimization of liquid crystal devices based on weakly conductive layers for lensing and beam steering

    NASA Astrophysics Data System (ADS)

    Beeckman, Jeroen; Nys, Inge; Willekens, Oliver; Neyts, Kristiaan

    2017-01-01

    Liquid crystals are mostly known for their use in displays, but over the past decade these materials have been applied in a number of other devices such as tunable lenses or beam steering devices. A common technique to realize a gradual electric field profile as is required to obtain a gradual refractive index profile in these applications is the use of weakly conductive materials. The weakly conductive layers are able to spread the voltage profile which is applied through well-conductive electrodes at the side of the weakly conductive layer. The simulation and design of such structures is not trivial because two or three dimensional quasi-static electric field profiles need to be calculated. This is due to the fact that the resistivity of the conductive layers and the dielectric properties of the liquid crystal are coupled. An exact solution requires solving a number of coupled differential equations. In this paper, we develop a model to simulate the RC-effects with an approximate model.

  7. 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).

  8. Beam steering laser assisted deposition system for high- T sub c superconducting thin film devices

    SciTech Connect

    Pham, T.T.; Chen, K.W. )

    1991-03-01

    We present the design and construction of a beam steering laser-assisted deposition system (LAD) for high quality epitaxial YBaCuO superconducting thin film production suitable for commercial application. Deposition of single layer or multilayer YBaCuO superconducting thin film on large and complex surfaced substrate is now feasible. Expitaxial and polycrystaline films with onsets at 90 K having 6 K transition widths have been produced. Dome-shaped magnetic shield enclosures, microwave cavity resonant in the TM{sub 010} mode, and short dipole antennas have been fabricated. The advantages of the laser ablation deposition method (J. T. Cheung and D. T. Chueng, J. Vac. Sci. Technol. {bold 21}, 182 (1982)) are its simplicity and cleanliness. Laser ablation deposition is a viable method to produce high quality thin film of the Tl-based compound (S. H. Liou and K. D. Aylesworth, Appl. Phys. Lett. {bold 54}, 760 (1989)) by using a small target in a sealed environment which is important in handling toxic material of a Tl-based compounds.

  9. 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

  10. 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.

  11. Beam Control of Extremely Agile Relaying Laser Source for Bifocal Relay Mirror Spacecraft

    DTIC Science & Technology

    2006-09-01

    Source (EARLS), which has the capability of automatically acquiring and directing a laser beam onto a satellite simulator while in motion. The...at the satellite simulator’s receiving telescope and maintain the laser within the telescope’s limits in the presence of structural disturbance...automatically acquiring and directing a laser beam onto a satellite simulator while in motion. The purpose of this thesis is to make the EARLS platform

  12. 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].

  13. 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.

  14. 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.

  15. Beam-steering in hollow ZrO2/SiO2 distributed Bragg reflector waveguides for one-dimensional RGB imaging

    NASA Astrophysics Data System (ADS)

    Gu, Xiaodong; Nakahama, Masanori; Ahmed, Moustafa; Bakry, Ahmed; Koyama, Fumio

    2014-03-01

    A novel one-dimensional beam deflector based on a hollow Bragg reflector waveguide for RGB imaging was proposed and evaluated by modeling. Large steering range over 30° is possible by only 100 nm change in the hollow air-core thickness. Electrostatic actuation enables fast and precise control of the beam-steering with a low operation voltage. An ultra-small divergence angle and super-high resolution are expected for device lengths of a few millimeters thanks to the high coherency of the output beam. The proposed hollow-waveguide type deflector is extremely compact and can be arrayed with high density.

  16. Empirical Agility

    DTIC Science & Technology

    2014-06-01

    documented the fact that Unmanned Aerial Vehicles (now more commonly called drones ) added substantially to the quality of surveillance, resulting in better...Battalions. CACI Inc.-Federal, Arlington, Virginia. 1977. DTIC Accession Number ADA123481. Olmstead, Joseph A., B. Leon Elder, and John M...greater agility – Drones improved agility in ground and air operations – Nelson’s C2 at Trafalgar demonstrated agility. Theater Level C2 During WW II

  17. Beam Steering Mechanism for EarthCARE Atmospheric Lidar Instrument- An Improved Piezoelectic Tip-Tilt Mechanism

    NASA Astrophysics Data System (ADS)

    Bourgain, Frederic; Sosnicki, Olivier; Barillot, Francois; Claeyssen, Frank; Lelay, Jean Pierre; Prevost, Eddie; Pain, Thierry; Germain, Benoit

    2013-09-01

    In the context of the ATLID instrument [1] embedded in the EarthCARE mission (Earth Cloud, Aerosol and Radiation Explorer), a Beam Steering Assembly is deviating a pulsed high energy UV laser beam to compensate the pointing misalignment between the emission and reception paths of ATLID with a very high stability and high resolution.Within the EarthCARE mission, led by ESA, Astrium is responsible for the ATLID instrument. The BSA development, manufacture and tests were assigned by Astrium to Sodern, an EADS filial.In this context, Cedrat Technologies was sub-contracted by Sodern to design, manufacture and test the performances of Beam Steering Mechanism flights models.This paper points out the main mechanism design issues:• High performances;• Mechanical and thermal stability;• Low power consumption;• High integration level;• High reliability and safety;• Cleanliness requirements.and examines how these issues have been approached by Cedrat Technologies and Sodern. Test results are reported when available.

  18. 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.

  19. 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)

  20. 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.

  1. Demonstration of enhanced emission and time delay beam steering using photoconductive terahertz source with multiple spot feed

    NASA Astrophysics Data System (ADS)

    Knotts, Michael E.; Denison, Douglas R.

    2009-05-01

    Excitation of electrically biased photoconductive switches with femtosecond optical pulses is a well established method of generating wide bandwidth (0.5 to 2.5 THz) pulses of terahertz frequency radiation. This method of pulse generation draws energy from the bias power supply to accelerate optically injected charge carriers, giving rise to a current pulse that can radiate into free space; nevertheless, the output power is limited by both poor coupling of the radiation out of the substrate and by charge carrier screening. By optimizing the electrode structures and illumination geometries it may be possible to address both of these limitations. To explore this idea, we have experimentally studied illumination with coherent array of two sources spaced by less than a wavelength and operated near saturation in a semi-insulating GaAs source. By illuminating with an array of N=2 spots, we demonstrate a doubling in output terahertz power with no increase in input optical power. This result is consistent with results that have been shown for optical excitation that has been stretched along the anode using cylindrical lenses; however, the array of two spots permits steering the beam by adjusting the relative time of arrival of the two exciting pulses. Experimental evidence of this beam steering is presented. With proper electrode design, this approach may ultimately enable an N-fold increase in output power with an array of N spots, the formation of narrow beams, and the adjustment of beam direction by control of the relative time of arrival of the exciting optical pulses.

  2. Long-range surface-plasmon-enhanced all-optical switching and beam steering through nonlinear Kerr effect

    NASA Astrophysics Data System (ADS)

    Kar, Aparupa; Goswami, Nabamita; Saha, Ardhendu

    2017-01-01

    A proposition toward all-optical tuning of long-range surface-plasmon-enhanced beam shifts and all-optical switching is implemented analytically by exploitation of Kerr effect induced refractive index change through varying pump light intensity in a multilayer long-range surface-plasmon configuration at 1550 nm. Through the optimized design comprising polydiacetylene para-toulene sulfonate as a Kerr polymer, a high-contrast all-optical switch with a pump intensity threshold of 0.15 GW/cm2 is proposed. The design also provides giant spatial and angular Goos-Hänchen and Imbert-Fedorov shifts at mm and µrad ranges along with wide range of tunability of beam shifts with the varying pump light intensity and the varying incident angle. Moreover, exact beam position and beam steering considering the conjoint effect of spatial and angular Goos-Hänchen and Imbert-Fedorov shifts for different incident polarizations are also obtained. This idea proffers a new possibility for pulse generation, optical sensors applications, optical modulation, geodetic surveying, etc.

  3. Simulation and experimental results for a phase retrieval-based algorithm for far-field beam steering and shaping

    NASA Astrophysics Data System (ADS)

    Roggemann, Michael C.; Welsh, Byron M.; Stone, Bradley R.; Su, Ting Ei

    2002-02-01

    Active laser-based electro-optical (EO) sensors on future aircraft and spacecraft will be used for a variety of missions and will be required to have a number of demanding technical characteristics. A key challenge to achieving these characteristics is the development of inexpensive, high degree of freedom optical wave front control devices, and the development of effective algorithms for controlling these devices. In this paper we present our research in the development of phase retrieval-based wave front control algorithms that can be used implemented with segmented liquid crystal-based wave front control devices. We have developed a wave front control algorithm that allows dynamic small-angle beam steering and shaping in the presence of an aberrating output window. Our approach is based on a phase retrieval algorithm to determine the optimal figure of a segmented wave front control device. Simulation and experimental results presented here show that this approach allows shaped far field patterns to be created and steered over small angles.

  4. Demonstration of Tunable Steering and Multiplexing of Two 28 GHz Data Carrying Orbital Angular Momentum Beams Using Antenna Array

    PubMed Central

    Xie, Guodong; Zhao, Zhe; Yan, Yan; Li, Long; Ren, Yongxiong; Ahmed, Nisar; Cao, Yinwen; Willner, Asher J.; Bao, Changjing; Wang, Zhe; Liu, Cong; Ziyadi, Morteza; Talwar, Shilpa; Sajuyigbe, Soji; Ashrafi, Solyman; Tur, Moshe; Molisch, Andreas F.; Willner, Alan E.

    2016-01-01

    In line-of-sight communication systems, accurate alignment between the transmitter and receiver is important to guarantee sufficient signal power at the receiver. Such alignment is even more important for orbital angular momentum (OAM) multiplexing systems since misalignment between the transmitter and receiver may cause crosstalk among channels. In this paper, we demonstrate the simultaneous generation and tunable steering of two OAM beams utilising a custom-designed circular antenna array at 28 GHz. We achieve a steering angle of up to 35 degrees from the antenna array normal. We find that (i) the steering angle of the generated OAM beams is limited by the emitting angle of the antenna elements, and (ii) a larger steering angle may degrade the mode purity of the generated OAM beams as well as induce inter-symbol-interference to each of the individual channels. Moreover, we demonstrate the transmission of two 1-Gbaud quadratic phase shift keying (QPSK) signal over the two steerable OAM beams with both multiplexed channels achieved bit error rates (BERs) of <3.8 × 10−3. PMID:27833168

  5. Demonstration of Tunable Steering and Multiplexing of Two 28 GHz Data Carrying Orbital Angular Momentum Beams Using Antenna Array

    NASA Astrophysics Data System (ADS)

    Xie, Guodong; Zhao, Zhe; Yan, Yan; Li, Long; Ren, Yongxiong; Ahmed, Nisar; Cao, Yinwen; Willner, Asher J.; Bao, Changjing; Wang, Zhe; Liu, Cong; Ziyadi, Morteza; Talwar, Shilpa; Sajuyigbe, Soji; Ashrafi, Solyman; Tur, Moshe; Molisch, Andreas F.; Willner, Alan E.

    2016-11-01

    In line-of-sight communication systems, accurate alignment between the transmitter and receiver is important to guarantee sufficient signal power at the receiver. Such alignment is even more important for orbital angular momentum (OAM) multiplexing systems since misalignment between the transmitter and receiver may cause crosstalk among channels. In this paper, we demonstrate the simultaneous generation and tunable steering of two OAM beams utilising a custom-designed circular antenna array at 28 GHz. We achieve a steering angle of up to 35 degrees from the antenna array normal. We find that (i) the steering angle of the generated OAM beams is limited by the emitting angle of the antenna elements, and (ii) a larger steering angle may degrade the mode purity of the generated OAM beams as well as induce inter-symbol-interference to each of the individual channels. Moreover, we demonstrate the transmission of two 1-Gbaud quadratic phase shift keying (QPSK) signal over the two steerable OAM beams with both multiplexed channels achieved bit error rates (BERs) of <3.8 × 10‑3.

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

    SciTech Connect

    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.

  7. Small phase pattern 2D beam steering and a single LCOS design of 40 1 × 12 stacked wavelength selective switches.

    PubMed

    Yang, Haining; Robertson, Brian; Wilkinson, Peter; Chu, Daping

    2016-05-30

    Two-dimensional beam steering by small, square, phase patterns as small as 50 × 50 pixels on a phase-only liquid crystal on silicon (LCOS) device is experimentally verified as suitable for the application of wavelength selective switches (WSSs), in terms of the diffraction efficiency and steering accuracy. This enables a proposed highly functional and versatile stacked switch architecture, where 40 independent 1 × 12 WSSs can be realised on a single 4k LCOS device. They can be configured to support a 1 × N WSSs with N≤144, or an N × N wavelength crossconnect with N≤12.

  8. Electro-Optic Beam Steering Using Non-Linear Organic Materials

    DTIC Science & Technology

    1993-08-01

    York (SUNY), Buffalo, for potential application to the Hughes electro - optic beam deflector device. Evaluations include electro - optic coefficient...response time, transmission, and resistivity. Electro - optic coefficient measurements were made at 633 nm using a simple reflection technique. The

  9. Acoustic beam steering by light refraction: illustration with directivity patterns of a tilted volume photoacoustic source.

    PubMed

    Raetz, Samuel; Dehoux, Thomas; Perton, Mathieu; Audoin, Bertrand

    2013-12-01

    The symmetry of a thermoelastic source resulting from laser absorption can be broken when the direction of light propagation in an elastic half-space is inclined relatively to the surface. This leads to an asymmetry of the directivity patterns of both compressional and shear acoustic waves. In contrast to classical surface acoustic sources, the tunable volume source allows one to take advantage of the mode conversion at the surface to control the directivity of specific modes. Physical interpretations of the evolution of the directivity patterns with the increasing light angle of incidence and of the relations between the preferential directions of compressional- and shear-wave emission are proposed. In order to compare calculated directivity patterns with measurements of normal displacement amplitudes performed on plates, a procedure is proposed to transform the directivity patterns into pseudo-directivity patterns representative of the experimental conditions. The comparison of the theoretical with measured pseudo-directivity patterns demonstrates the ability to enhance bulk-wave amplitudes and to steer specific bulk acoustic modes by adequately tuning light refraction.

  10. Two-dimensional analytic modeling of acoustic diffraction for ultrasonic beam steering by phased array transducers.

    PubMed

    Wang, Tiansi; Zhang, Chong; Aleksov, Aleksandar; Salama, Islam; Kar, Aravinda

    2017-04-01

    Phased array ultrasonic transducers enable modulating the focal position of the acoustic waves, and this capability is utilized in many applications, such as medical imaging and non-destructive testing. This type of transducers also provides a mechanism to generate tilted wavefronts in acousto-optic deflectors to deflect laser beams for high precision advanced laser material processing. In this paper, a theoretical model is presented for the diffraction of ultrasonic waves emitted by several phased array transducers into an acousto-optic medium such as TeO2 crystal. A simple analytic expression is obtained for the distribution of the ultrasonic displacement field in the crystal. The model prediction is found to be in good agreement with the results of a numerical model that is based on a non-paraxial multi-Gaussian beam (NMGB) model.

  11. Infrared beam-steering using acoustically modulated surface plasmons over a graphene monolayer

    NASA Astrophysics Data System (ADS)

    Chen, P.-Y.; Farhat, M.; Askarpour, A. N.; Tymchenko, M.; Alù, A.

    2014-09-01

    We model and design a graphene-based infrared beamformer based on the concept of leaky-wave (fast traveling wave) antennas. The excitation of infrared surface plasmon polaritons (SPPs) over a ‘one-atom-thick’ graphene monolayer is typically associated with intrinsically ‘slow light’. By modulating the graphene with elastic vibrations based on flexural waves, a dynamic diffraction grating can be formed on the graphene surface, converting propagating SPPs into fast surface waves, able to radiate directive infrared beams into the background medium. This scheme allows fast on-off switching of infrared emission and dynamic tuning of its radiation pattern, beam angle and frequency of operation, by simply varying the acoustic frequency that controls the effective grating period. We envision that this graphene beamformer may be integrated into reconfigurable transmitter/receiver modules, switches and detectors for THz and infrared wireless communication, sensing, imaging and actuation systems.

  12. 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.

  13. A Method for Eliminating Beam Steering Error for the Modulated Absorption-Emission Thermometry Technique

    DTIC Science & Technology

    2014-01-01

    currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ADDRESS. 1. REPORT DATE (DD-MM-YYYY) Jan 2014 2. REPORT TYPE Technical...Paper 3. DATES COVERED (From - To) Jan 2014- June 2014 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER In-House A Method for Eliminating Beam...14194 14. ABSTRACT Modulated absorption-emission thermometry (MAET) is a non-intrusive, radiometric technique for measuring line-of-sight average

  14. 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.

  15. 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

  16. Agile Metrics: Progress Monitoring of Agile Contractors

    DTIC Science & Technology

    2014-01-01

    can be tailored to leverage the iterative nature of Agile meth- ods. Using optional contract funding lines or indefinite delivery indefinite quantity... naturally created during the execution of the Agile implementation. In the following paragraphs, we identify issues to consider in building an Agile...employing Agile methods [Hartman 2006]. Be prepared to mine and effectively use the metrics data that naturally occur in typical Ag- ile teams. In

  17. Millimeter-wave beam forming and dynamic steering using an optically controlled photo-injected Fresnel zone plate antenna at 94 GHz

    NASA Astrophysics Data System (ADS)

    Gallacher, Tom F.; Robertson, D. A.; Smith, G. M.

    2012-06-01

    We present results for a rapid, precise and wide field-of-view scanning antenna for use at millimeter and submillimeter wavelengths, based on the photo-injected Fresnel zone plate antenna (piFZPA) method. Our work demonstrates the potential of this technology as a viable solution to a range of applications demanding video rate imagery at these frequencies. This technique is based on optically exciting free carriers in a semiconductor substrate, to form a plasma-based Fresnel zone plate antenna, which focuses and steers incident millimeter-wave beams. By reconfiguring the optically projected pattern, it is possible to dynamically, and rapidly, manipulate (sub) millimeter-wave beams within a 3D volume. It is believed that the little attention devoted to this method since it was first demonstrated 20 years ago has been due to the high illumination densities required for sufficient plasma injection. Our work has made significant improvements in addressing this requirement and the technique is demonstrated using simple, commercially available hardware. We present proof-of-principle experiments at 94GHz incorporating a commercial data projector. The 100mm diameter piFZPA achieves 37dBi directivity, excellent beam symmetry, beam steering in two dimensions over a +/-30° field-of-view, and precise beam control and repeatability. Whilst current demonstrations are restricted to less than 20 beams per second with the current implementation, the technique is capable of achieving beam scanning rates of more than 10,000 beams per second, suitable for video-rate imagery. We also present, believed to be for the first time, results of a piFZPA integrated into a short range, 94GHz, 3D imaging radar.

  18. Toward steering a jet of particles into an x-ray beam with optically induced forces

    NASA Astrophysics Data System (ADS)

    Eckerskorn, Niko; Bowman, Richard; Kirian, Richard A.; Awel, Salah; Wiedorn, Max; Küpper, Jochen; Padgett, Miles J.; Chapman, Henry N.; Rode, Andrei V.

    2015-08-01

    Optical trapping of light-absorbing particles in a gaseous environment is governed by a laser-induced photophoretic force, which can be orders of magnitude stronger than the force of radiation pressure induced by the same light intensity. In spite of many experimental studies, the exact theoretical background underlying the photophoretic force and the prediction of its influence on the particle motion is still in its infancy. Here, we report the results of a quantitative analysis of the photophoretic force and the stiffness of trapping achieved by levitating graphite and carbon-coated glass shells of calibrated sizes in an upright diverging hollow-core vortex beam, which we refer to as an `optical funnel'. The measurements of forces were conducted in air at various gas pressures in the range from 5 mbar to 2 bar. The results of these measurements lay the foundation for developing a touch-free optical system for precisely positioning sub-micrometer bioparticles at the focal spot of an x-ray free electron laser, which would significantly enhance the efficiency of studying nanoscale morphology of proteins and biomolecules in femtosecond coherent diffractive imaging experiments.

  19. 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.

  20. Bifunctional plasmonic metamaterials enabled by subwavelength nano-notches for broadband, polarization-independent enhanced optical transmission and passive beam-steering.

    PubMed

    Jiang, Zhi Hao; Lin, Lan; Bossard, Jeremy A; Werner, Douglas H

    2013-12-16

    In this work, we present the design, numerical experiments, and analysis of a plasmonic metamaterial thin film based on subwavelength nano-notch loaded modified fishnet structures. The resulting device offers a simultaneous bandpass filtering functionality with a broad enhanced optical transmission window and a gapless negative-zero-positive index transition to enable polarization-independent passive beam-steering. This unique characteristic is made possible by the introduced subwavelength nano-notches, which provide fine tuning and hybridization of the external and internal surface plasmon polariton modes. This allows tailoring of the dispersive properties of the plasmonic metamaterial for broadband operation. Specifically, a multilayer nanostructured modified fishnet with feature sizes accessible by modern nanofabrication techniques is presented, exhibiting a broad passband at the mid-infrared wavelengths from 3.0 to 3.7 µm and stopbands elsewhere in the 2.5 ~4.5 µm window. The transmittance normalized to area is around 3 dB within the broad 20% bandwidth of the passband. Additionally, the effective index undergoes a smooth transition from negative unity through zero to positive unity with low loss within the passband. The physical mechanism and the angular dispersion of the metamaterial are analyzed in detail. Finally, full-wave simulations of a prism formed from this metamaterial are performed to demonstrate that the proposed structure achieves simultaneous polarization-insensitive passive beam-steering and filtering functionalities.

  1. 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

  2. Agility Quotient (AQ)

    DTIC Science & Technology

    2014-06-01

    system?s Agility IQ ?? and ?What is the requisite amount of Agility that is required?? This paper suggests a way forward and illustrates it, in the...answer two questions. “How can we measure a system’s Agility IQ ?” and “What is the requisite amount of Agility that is required?” This paper...agility is worth our attention. AQ can be patterned after the Intelligence Quotient ( IQ ). IQ is a score that is associated with educational potential

  3. 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.

  4. 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.

  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. Clean, Agile Processing Technology.

    DTIC Science & Technology

    1997-12-01

    Research ltr dtd 10 Jun 98 THIS PAGE IS UNCLASSIFIED FINAL REPORT CLEAN, AGILE PROCESSING TECHNOLOGY Contract # N00014-96-C-0139 PI: S. W . Sinton...Agile Processing Technology . T UNCLAS I N Sinton, S. W.IN S REQUIRED FOR (Explain needin detaiO E C This document is requested by the Canadian Department

  7. Focused Logistics: Putting Agility in Agile Logistics

    DTIC Science & Technology

    2011-05-19

    envisioned an agile and adaptable logstics system built around common situational understanding.5 The Focused Logistics concept specified the requirement to...the tracking of resources moving through the TD network. As a result, 112 Ibid, 20. 113 Ibid, 18-20. 39 distribution centers tagged inbound

  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. Tip-tilt mirror suspension: beam steering for advanced laser interferometer gravitational wave observatory sensing and control signals.

    PubMed

    Slagmolen, Bram J J; Mullavey, Adam J; Miller, John; McClelland, David E; Fritschel, Peter

    2011-12-01

    We describe the design of a small optic suspension system, referred to as the tip-tilt mirror suspension, used to isolate selected small optics for the interferometer sensing and control beams in the advanced LIGO gravitational wave detectors. The suspended optics are isolated in all 6 degrees of freedom, with eigenmode frequencies between 1.3 Hz and 10 Hz. The suspended optic has voice-coil actuators which provide an angular range of ±4 mrad in the pitch and yaw degrees of freedom.

  10. 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°.

  11. 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.

  12. 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?

  13. Beam-Based Alignment of the NLC Main Linac, Part Two: Dispersion-Free Steering and Dispersion Bumps(LCC-0071)

    SciTech Connect

    Tenenbaum, P

    2003-11-06

    The standard prescription for NLC main linac steering assumes that the RMS offset between a quad's magnetic center and the corresponding BPM's electrical center can be determined at the level of a micron. This is a fearsome requirement, and will be particularly difficult to achieve if hybrid iron/permanent magnet quads are used in the main linac. As an alternative, the Dispersion Free Steering (DFS) [1] algorithm is adapted to the NLC main linac environment; the DFS algorithm does not require knowledge of the quad-BPM offsets. The results of simulation studies of this adaptation are presented. In addition, the use of closed orbit bumps to globally correct dispersive emittance growth is considered. The studies indicate that DFS can be used successfully in the NLC main linac environment, and that dispersion bumps are a useful addition to the linac steering ''toolbox,'' regardless of the main algorithm selected.

  14. Modeling of the diffraction efficiency and polarization sensitivity for a liquid crystal 2D spatial light modulator for reconfigurable beam steering.

    PubMed

    James, Richard; Fernández, F Aníbal; Day, Sally E; Komarcević, Milos; Crossland, William A

    2007-08-01

    A nematic liquid crystal spatial light modulator used as a phase-modulating device and operating in the reflective mode is analyzed using three-dimensional modeling. Two configurations, which differ in their electrode placement relative to a fixed quarter-wave plate, are considered across a range of steering directions, with the grating conformal and in some cases oblique to the pixel grid. For each steering direction the sensitivity of the diffraction orders to the polarization state of the incident wavefront is studied. Optimal alignment of the liquid crystal is suggested to reduce this sensitivity.

  15. 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.

  16. One — dimensional laser beam steering using frequency detuning in two — wave mixing with a BaTiO 3 crystal

    NASA Astrophysics Data System (ADS)

    Dharmsaktu, K. S.; Joseph, Joby; Singh, Kehar

    2000-06-01

    We demonstrate a method of one-dimensional laser beam deflection using frequency detuning in two-wave mixing. Energy exchange between the interfering beams in a photo-refractive BaTiO 3 crystal has been used for deflection of a pump beam into predetermined probe beam directions. A one-dimensional array of several beams is generated from a single probe beam, employing a piezo-mirror and beam splitter combination. Probe beams so produced are detuned by exciting the piezo-mirror with a periodic near-saw-tooth voltage so as to produce running fringes. However, stable holographic gratings are recorded by matching the frequency of the probe beam with that of a pump beam reflected from another vibrating piezo-mirror, thereby controlling the direction of beam deflection.

  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. Photorefractive beam-steering system that uses energy transfer in a BaTiO3 crystal for a fiber-array interconnect

    NASA Astrophysics Data System (ADS)

    Mathey, P.; Mercier, R.; Pauliat, G.; Roosen, G.; Gravey, Ph.

    1995-12-01

    A beam-control system to write gratings on a holographic plane is studied. The arrangement is designed to interconnect two 1024 monomode fiber arrays. The beam-control system is composed of one incident beam toward 1024 positions, and a collimating system, which adapts the shape of the deflected beam to the holographic plane. The

  19. Operational Agility (La Maniabilite Operationnelle)

    DTIC Science & Technology

    1994-04-01

    describe how to go further and how to set up an analytical framework for the analysis of another fundamental property of modern combat aircraft, that is... analytical framework for the analysis of airframe agility and for the derivation of agility metrics. A general consensus has been found in relating agility...Gianchecchi, Aernmacchi Lt Col. G. Fristachi, Italian Air Force Prof. M. Innocenti, Auburn University/University of Pisa United Kingdom Mr P. Gordon

  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. 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.

  2. 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.

  3. Steering algorithms for a small recirculating heavy-ion accelerator

    SciTech Connect

    Sharp, W.M.; Grote, D.P.; Hemandez, G.W.

    1997-11-07

    Beam-steering algorithms are proposed for a small recirculating induction accelerator being built at the Lawrence Livermore National Laboratory. The principal problem is that the transverse position and velocity of the beam must be inferred from capacitive position monitors, and this determination is complicated by the limited probe resolution and by the lattice errors within steering modules. The fluid/envelope code CIRCE is used to evaluate these algorithms.

  4. Planar Arrays on Lattices and Their FFT Steering, a Primer

    DTIC Science & Technology

    2011-04-29

    by a tall B, so we cannot properly term it the inverse of B. A different terminology is called for. The Moore - Penrose pseudoinverse of any matrix B...lattice and using terminated guard elements at the array periphery. The second is multi-beam phase-shift steering of such arrays using generalized Cooley...FFT realization of the general multidimensional DFT for beam steering is developed using nested sublattice chains. The needed lattice basics are

  5. 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.

  6. Towards Agile Ontology Maintenance

    NASA Astrophysics Data System (ADS)

    Luczak-Rösch, Markus

    Ontologies are an appropriate means to represent knowledge on the Web. Research on ontology engineering reached practices for an integrative lifecycle support. However, a broader success of ontologies in Web-based information systems remains unreached while the more lightweight semantic approaches are rather successful. We assume, paired with the emerging trend of services and microservices on the Web, new dynamic scenarios gain momentum in which a shared knowledge base is made available to several dynamically changing services with disparate requirements. Our work envisions a step towards such a dynamic scenario in which an ontology adapts to the requirements of the accessing services and applications as well as the user's needs in an agile way and reduces the experts' involvement in ontology maintenance processes.

  7. 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.

  8. 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

  9. 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.

  10. 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.

  11. Inserting Agility in System Development

    DTIC Science & Technology

    2012-07-01

    Agile IT Acquisition, IT Box, Scrum Inserting Agility in System Development Matthew R. Kennedy and Lt Col Dan Ward, USAF With the fast-paced nature...1,700 individuals and 71 countries, found Scrum and eXtreme Programming to be the most widely followed method- ologies (VersionOne, 2007). Other...University http://www.dau.mil 259 Defense ARJ, July 2012, Vol. 19 No. 3 : 249–264 Scrum Scrum is a framework used for project management, which is

  12. 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.

  13. Experimental temporal quantum steering

    NASA Astrophysics Data System (ADS)

    Bartkiewicz, Karol; Černoch, Antonín; Lemr, Karel; Miranowicz, Adam; Nori, Franco

    2016-11-01

    Temporal steering is a form of temporal correlation between the initial and final state of a quantum system. It is a temporal analogue of the famous Einstein-Podolsky-Rosen (spatial) steering. We demonstrate, by measuring the photon polarization, that temporal steering allows two parties to verify if they have been interacting with the same particle, even if they have no information about what happened with the particle in between the measurements. This is the first experimental study of temporal steering. We also performed experimental tests, based on the violation of temporal steering inequalities, of the security of two quantum key distribution protocols against individual attacks. Thus, these results can lead to applications for secure quantum communications and quantum engineering.

  14. Experimental temporal quantum steering

    PubMed Central

    Bartkiewicz, Karol; Černoch, Antonín; Lemr, Karel; Miranowicz, Adam; Nori, Franco

    2016-01-01

    Temporal steering is a form of temporal correlation between the initial and final state of a quantum system. It is a temporal analogue of the famous Einstein-Podolsky-Rosen (spatial) steering. We demonstrate, by measuring the photon polarization, that temporal steering allows two parties to verify if they have been interacting with the same particle, even if they have no information about what happened with the particle in between the measurements. This is the first experimental study of temporal steering. We also performed experimental tests, based on the violation of temporal steering inequalities, of the security of two quantum key distribution protocols against individual attacks. Thus, these results can lead to applications for secure quantum communications and quantum engineering. PMID:27901121

  15. 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.

  16. Agile automated vision

    NASA Astrophysics Data System (ADS)

    Fandrich, Juergen; Schmitt, Lorenz A.

    1994-11-01

    The microelectronic industry is a protagonist in driving automated vision to new paradigms. Today semiconductor manufacturers use vision systems quite frequently in their fabs in the front-end process. In fact, the process depends on reliable image processing systems. In the back-end process, where ICs are assembled and packaged, today vision systems are only partly used. But in the next years automated vision will become compulsory for the back-end process as well. Vision will be fully integrated into every IC package production machine to increase yields and reduce costs. Modem high-speed material processing requires dedicated and efficient concepts in image processing. But the integration of various equipment in a production plant leads to unifying handling of data flow and interfaces. Only agile vision systems can act with these contradictions: fast, reliable, adaptable, scalable and comprehensive. A powerful hardware platform is a unneglectable requirement for the use of advanced and reliable, but unfortunately computing intensive image processing algorithms. The massively parallel SIMD hardware product LANTERN/VME supplies a powerful platform for existing and new functionality. LANTERN/VME is used with a new optical sensor for IC package lead inspection. This is done in 3D, including horizontal and coplanarity inspection. The appropriate software is designed for lead inspection, alignment and control tasks in IC package production and handling equipment, like Trim&Form, Tape&Reel and Pick&Place machines.

  17. 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.

  18. 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

  19. 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

  20. Detection of quantum steering in multipartite continuous-variable Greenberger-Horne-Zeilinger-like states

    NASA Astrophysics Data System (ADS)

    Wang, Meng; Xiang, Yu; He, Qiongyi; Gong, Qihuang

    2015-01-01

    The multipartite entangled state has drawn broad attention for both foundations of quantum mechanics and applications in quantum information processing. Here, we study the spatially separated N -partite continuous-variable Greenberger-Horne-Zeilinger-like states, which can be produced by a linear optical network with squeezed light and N -1 beamsplitters. We investigate the properties of multipartite Einstein-Podolsky-Rosen steering possessed by those states, and find that the steering of a given quantum mode is allowed when not less than half of the modes within the states take part in the steering group. This is certified by the detection of the correlation between position and momentum quadratures of the steered mode and a combination of quadratures of other modes inside the steering group. The steering is evidenced by the high correlation where the steering group can infer the quadratures of the steered mode to high precision, i.e., below the quantum limit for the position and momentum quadratures of the steered quantum mode. We also examine the influence of inefficiency on the multipartite steering, and derive the threshold of the loss tolerance. Furthermore, we discuss the collective N -partite steering induced by the asymmetric loss on beams, which exists when a given quantum mode can only be steered by all the remaining N -1 modes collaboratively. The present multipartite steering correlation may have potential applications in certain quantum information tasks where the issue of trust is important, such as one-sided device-independent quantum secret sharing.

  1. 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.

  2. 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.

  3. Magnetic steering of a helicon double layer thruster

    SciTech Connect

    Charles, C.; Boswell, R. W.; Cox, W.; Laine, R.; MacLellan, P.

    2008-11-17

    The ion beam generated by a helicon double layer has been electrically steered up to 20 deg. off axis by using a solenoid placed normal to the two axial solenoids of the helicon plasma source without significantly changing the beam exhaust velocity.

  4. 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.

  5. Attitude steering for space shuttle based synthetic aperture radars

    NASA Technical Reports Server (NTRS)

    Chang, C. Y.; Curlander, J. C.

    1992-01-01

    A technique is presented to steer the antenna beam to the zero-Doppler line for a spacecraft platform which operates in a non-zero roll attitude. The purposes of employing this attitude steering technique are reduction of the Doppler centroid error caused by the variation in target elevation; reduction of the Doppler centroid bound; and reduction of the Doppler drift. It is shown that a fixed attitude sequence can be easily accommodated in the radar command sequence to achieve nearly zero-Doppler steering. Implementation of this technique improves the image quality as well as simplifies the processor design.

  6. 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.

  7. Hybrid Steering Systems for Free-Space Quantum Communication

    DTIC Science & Technology

    2007-03-01

    full hemisphere steering range [ 2 ]. The second technology is the acousto - optic Bragg cell, virtually inertia-less but with a very limited steering...input and output signals of acousto - optic deflectors (b) Varying roll angle of gimbal’s pointing mechanism (cross-shaped optical mount) (a...ABSTRACT The proposed research will utilize a mechanical gimbal for extended range of optical connectivity, and a fast beam deflector to create a hybrid

  8. Agile Development of Advanced Prototypes

    DTIC Science & Technology

    2014-11-01

    genetically modified babies. A case where researchers supplemented women’s defective mitochondria with healthy mitochondria from a donor was...and immersive experience showing genetic engineering’s implication for the future of medicine. 15. SUBJECT TERMS Agile Development, Games for...provoking perspective on genetic engineering’s implication for the future of medicine. Experiencing Living with Prostheses (Xense) During this period

  9. Making Agile Work for You

    DTIC Science & Technology

    2011-07-20

    Extreme Programming (XP) • SCRUM • Dynamic Systems Development Method (DSDM) • Adaptive Software Development • Crystal • Feature-Driven Development...Carnegie Mellon University Twitter #seiwebinar SCRUM Scrum is an iterative, incremental methodology for managing agile software projects. The Team

  10. 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

  11. Superactivation of quantum steering

    NASA Astrophysics Data System (ADS)

    Quintino, Marco Túlio; Brunner, Nicolas; Huber, Marcus

    2016-12-01

    We consider Einstein-Podolsky-Rosen steering in the regime where the parties can perform collective measurements on many copies of a given shared entangled state. We derive a simple and efficient condition for guaranteeing that an entangled state is k -copy steerable. In particular, we show that any two-qubit and qubit-qutrit entangled state is k -copy steerable. This allows us to discuss the effect of superactivation of steering, whereby an entangled state that is unsteerable (i.e., admits a local hidden state model) in the one-copy regime becomes k -copy steerable. We provide examples with few copies and low dimensions. Our results give evidence that entanglement and steering could become equivalent in the multicopy regime.

  12. A Comparison between Compounding Techniques using Large Beam-Steered Plane Wave Imaging for Blood Vector Velocity Imaging in a Carotid Artery Model.

    PubMed

    Saris, Anne; Hansen, Hendrik; Fekkes, Stein; Nillesen, Maartje; Rutten, Marcel; de Korte, Chris

    2016-09-07

    Conventional color Doppler imaging is limited, since it only provides velocity estimates along the ultrasound beam direction for a restricted field of view at a limited frame rate. High frame rate speckle tracking, using plane wave transmits, has shown potential for 2D blood velocity estimation. However, due to the lack of focusing in transmit, image quality gets reduced, which hampers speckle tracking. Although ultrafast imaging facilitates improved clutter filtering, it still remains a major challenge in blood velocity estimation. Signal drop-outs and poor velocity estimates are still present for high beam-to-flow angles and low blood flow velocities. In this work, ultrafast plane wave imaging was combined with multi-scale speckle tracking to assess the 2D blood velocity vector in a common carotid artery (CCA) flow field. A multi-angled plane wave imaging sequence was used to compare the performance of displacement compounding, coherent compounding and compound speckle tracking. Zero-degree plane wave imaging was also evaluated. The performance of the methods was evaluated before and after clutter filtering for the large range of velocities (0 to 1.5 m/s) that are normally present in a healthy CCA during the cardiac cycle. An extensive simulation study was performed, based on a sophisticated model of the CCA, to investigate and evaluate the performance of the methods at different pulse repetition frequencies and signal-to-noise levels. In vivo data were acquired of a healthy carotid artery bifurcation to support the simulation results. In general, methods utilizing compounding after speckle tracking, i.e., displacement compounding and compound speckle tracking, were least affected by clutter filtering and provided the most robust and accurate estimates for the entire velocity range. Displacement compounding, which uses solely axial information to estimate the velocity vector, provided most accurate velocity estimates, although it required sufficiently high pulse

  13. A Comparison Between Compounding Techniques Using Large Beam-Steered Plane Wave Imaging for Blood Vector Velocity Imaging in a Carotid Artery Model.

    PubMed

    Saris, Anne E C M; Hansen, Hendrik H G; Fekkes, Stein; Nillesen, Maartje M; Rutten, Marcel C M; de Korte, Chris L

    2016-11-01

    Conventional color Doppler imaging is limited, since it only provides velocity estimates along the ultrasound beam direction for a restricted field of view at a limited frame rate. High-frame-rate speckle tracking, using plane wave transmits, has shown potential for 2-D blood velocity estimation. However, due to the lack of focusing in transmit, image quality gets reduced, which hampers speckle tracking. Although ultrafast imaging facilitates improved clutter filtering, it still remains a major challenge in blood velocity estimation. Signal dropouts and poor velocity estimates are still present for high beam-to-flow angles and low blood flow velocities. In this paper, ultrafast plane wave imaging was combined with multiscale speckle tracking to assess the 2-D blood velocity vector in a common carotid artery (CCA) flow field. A multiangled plane wave imaging sequence was used to compare the performance of displacement compounding, coherent compounding, and compound speckle tracking. Zero-degree plane wave imaging was also evaluated. The performance of the methods was evaluated before and after clutter filtering for the large range of velocities (0-1.5 m/s) that are normally present in a healthy CCA during the cardiac cycle. An extensive simulation study was performed, based on a sophisticated model of the CCA, to investigate and evaluate the performance of the methods at different pulse repetition frequencies and signal-to-noise levels. In vivo data were acquired of a healthy carotid artery bifurcation to support the simulation results. In general, methods utilizing compounding after speckle tracking, i.e., displacement compounding and compound speckle tracking, were least affected by clutter filtering and provided the most robust and accurate estimates for the entire velocity range. Displacement compounding, which uses solely axial information to estimate the velocity vector, provided most accurate velocity estimates, although it required sufficiently high pulse

  14. CCCT - Patient Advocate Steering Committee

    Cancer.gov

    The Patient Advocate Steering Committee (PASC) works to ensure advocates involved with the Scientific Steering Committees (SSCs) are completely integrated in the development, implementation, and monitoring of clinical trials within those groups.

  15. Steering Performance, Tactical Vehicles

    DTIC Science & Technology

    2015-07-29

    the path of the vehicle is difficult to conu·ol which may lead to more aborted test u·ials than using driver-conu·olled steer inputs. Using a driver...reduces both the time required to prepare the vehicle and the probability of aborted u·ials. This allows more attempts to be made, but test results

  16. 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.

  17. 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.

  18. Barriers to Achieving Mentally Agile Junior Leaders

    DTIC Science & Technology

    2009-01-21

    To help answer this question, this paper will describe the operational environment the agile leader must be prepared to operate within and the...senior leadership identified their need over eight years ago? To help answer this question, this paper will describe the operational environment the agile...to the reader. BARRIERS TO ACHIEVING MENTALLY AGILE JUNIOR LEADERS Persistent conflict and change characterize the strategic environment . We have

  19. Towards a Comparative Measure of Legged Agility

    DTIC Science & Technology

    2014-06-01

    so for this paper we explore the implications of a well-cited definition within the sports science community holding that agility is “a rapid whole...systems will have negligible agility according to our metric in accor- dance with biological observations that these motions require significantly less...W. Young, “Agility literature review: Classifications, training and testing,” Journal of sports sciences, vol. 24, no. 9, pp. 919–932, 2006. 19. D. L

  20. 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.

  1. Assessment of proposed fighter agility metrics

    NASA Technical Reports Server (NTRS)

    Liefer, Randall K.; Valasek, John; Eggold, David P.; Downing, David R.

    1990-01-01

    This paper presents the results of an analysis of proposed metrics to assess fighter aircraft agility. A novel framework for classifying these metrics is developed and applied. A set of transient metrics intended to quantify the axial and pitch agility of fighter aircraft is evaluated with a high fidelity, nonlinear F-18 simulation. Test techniques and data reduction method are proposed, and sensitivities to pilot introduced errors during flight testing is investigated. Results indicate that the power onset and power loss parameters are promising candidates for quantifying axial agility, while maximum pitch up and pitch down rates are for quantifying pitch agility.

  2. 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.

  3. 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

    2015-04-06

    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.

  4. 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.

  5. 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.

  6. 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…

  7. The RITE Approach to Agile Acquisition

    DTIC Science & Technology

    2013-04-01

    Review (SVR), and Production Readiness Review ( PRR ), which were evaluated against Agile development requirements. Further analysis was conducted...Audit (FCA), PRR , Operational Test Readiness Review (OTRR), Physical Configuration Audit (PCA), Integration Readiness Review (IRR), In Service...Technology (DSB Task Force, 2009, p. 48) In the context of the primary milestone reviews (PDR, CDR, and SVR/ PRR ), a nominal Agile development structure was

  8. 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…

  9. 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…

  10. Active infrared materials for beam steering.

    SciTech Connect

    Brener, Igal; Reno, John Louis; Passmore, Brandon Scott; Gin, Aaron V.; Shaner, Eric Arthur; Miao, Xiaoyu; Barrick, Todd A.

    2010-10-01

    The mid-infrared (mid-IR, 3 {micro}m -12 {micro}m) is a highly desirable spectral range for imaging and environmental sensing. We propose to develop a new class of mid-IR devices, based on plasmonic and metamaterial concepts, that are dynamically controlled by tunable semiconductor plasma resonances. It is well known that any material resonance (phonons, excitons, electron plasma) impacts dielectric properties; our primary challenge is to implement the tuning of a semiconductor plasma resonance with a voltage bias. We have demonstrated passive tuning of both plasmonic and metamaterial structures in the mid-IR using semiconductors plasmas. In the mid-IR, semiconductor carrier densities on the order of 5E17cm{sup -3} to 2E18cm{sup -3} are desirable for tuning effects. Gate control of carrier densities at the high end of this range is at or near the limit of what has been demonstrated in literature for transistor style devices. Combined with the fact that we are exploiting the optical properties of the device layers, rather than electrical, we are entering into interesting territory that has not been significantly explored to date.

  11. 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.

  12. Fighter agility metrics, research, and test

    NASA Technical Reports Server (NTRS)

    Liefer, Randall K.; Valasek, John; Eggold, David P.

    1990-01-01

    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 completed set of transient agility metrics is evaluated with a high fidelity, nonlinear F-18 simulation provided by the NASA Dryden Flight Research Center. 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. Simulation documentation and user instructions are provided in an appendix.

  13. 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.

  14. 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.

  15. 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.

  16. Quantum coherence of steered states.

    PubMed

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

    2016-01-19

    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.

  17. 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

  18. 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…

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

    NASA Astrophysics Data System (ADS)

    Shi, Yubin; Zhang, Jianmin; Zhang, Zhen

    2016-12-01

    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.

  20. Steer assistance for teleoperation

    NASA Astrophysics Data System (ADS)

    Pape, Olivier; Houbloup, Philippe; Leveque, Stephane

    2005-05-01

    Giat Industries, expert in combat system, designs and integrates the technologies (electrical network, mechanical design, ergonomic and mobility command and control) for the French military and civil robotic. One of the main problems of current robotics is to treat the lack of operator's perception due to teleoperation. The article details the assistance for the steer control part of mobility command and control. The purpose of the assistance is to secure the vehicle, to insure the continuity of the command (in particular for tracked vehicle equipped of hydrostatic steering group), and to adapt the command (to use all the range of the command even at high speed and to adapt the speed to the desired curve). The advantage of the system presented in the article is to filter the order first and to transmit to the actuators only safe orders preserving the vehicle. This approach transforms the telepilot's order watching and correction problem, to a telepilot's order filtering problem. We pass here, from a logical "a posteriori" to a logical of "a priori" processing. The assistance includes: a model of the dynamic behavior of the vehicle and an open loop, some feed forward with appropriate filters and a closed loop. The article presents the result of the command studies from time simulation to "man on the loop" simulation. This system, at present time applied to the French Observation Robot demonstrator SYRANO (developped for the DGA-French Defence Procurement Agency), is the subject of a patent.

  1. Developing communications requirements for Agile Product Realization

    SciTech Connect

    Forsythe, C.; Ashby, M.R.

    1994-03-01

    Sandia National Laboratories has undertaken the Agile Product Realization for Innovative electroMEchanical Devices (A-PRIMED) pilot project to develop and implement technologies for agile design and manufacturing of electrochemical components. Emphasis on information-driven processes, concurrent engineering and multi-functional team communications makes computer-supported cooperative work critical to achieving significantly faster product development cycles. This report describes analyses conducted in developing communications requirements and a communications plan that addresses the unique communications demands of an agile enterprise.

  2. Agile Leaders, Agile Institutions: Educating Adaptive and Innovative Leaders for Today and Tomorrow

    DTIC Science & Technology

    2005-03-18

    to organizational learning , specifically for militaries at war. With these lenses and informed by observations from the CCCs, the paper advances...rapid, effective organizational learning is the essence of organizational agility. In line with this paper’s concept of individual agility...organizational agility is a metaphor for organizational learning that is faster, more flexible, and more sensitive to the speed with which individual experiential

  3. 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.

  4. 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.

  5. Test Methods for Robot Agility in Manufacturing

    PubMed Central

    Downs, Anthony; Harrison, William; Schlenoff, Craig

    2017-01-01

    Purpose The paper aims to define and describe test methods and metrics to assess industrial robot system agility in both simulation and in reality. Design/methodology/approach The paper describes test methods and associated quantitative and qualitative metrics for assessing robot system efficiency and effectiveness which can then be used for the assessment of system agility. Findings The paper describes how the test methods were implemented in a simulation environment and real world environment. It also shows how the metrics are measured and assessed as they would be in a future competition. Practical Implications The test methods described in this paper will push forward the state of the art in software agility for manufacturing robots, allowing small and medium manufacturers to better utilize robotic systems. Originality / value The paper fulfills the identified need for standard test methods to measure and allow for improvement in software agility for manufacturing robots. PMID:28203034

  6. Agile manufacturing concepts and opportunities in ceramics

    SciTech Connect

    Booth, C.L.; Harmer, M.P.

    1995-08-01

    In 1991 Lehigh University facilitated seminars over a period of 8 months to define manufacturing needs for the 21st century. They concluded that the future will be characterized by rapid changes in technology advances, customer demands, and shifts in market dynamics and coined the term {open_quotes}Agile Manufacturing{close_quotes}. Agile manufacturing refers to the ability to thrive in an environment of constant unpredictable change. Market opportunities are attacked by partnering to form virtual firms to dynamically obtain the required skills for each product opportunity. This paper will describe and compare agile vs. traditional concepts of organization & structure, management policy and ethics, employee environment, product focus, information, and paradigm shift. Examples of agile manufacturing applied to ceramic materials will be presented.

  7. Decision Science Challenges for C2 Agility

    DTIC Science & Technology

    2014-06-01

    Controlled and automatic human information processing: II. Perceptual learning , automatic attending and a general theory . Psychological Review, 84 (2...1 19 th ICCRTS “C2 Agility: Lessons Learned from Research and Operations” Decision Science Challenges for C2 Agility Topic 1 (First...systems. We have two vectors there. The first vector would be in things like man-machine interface. The second ... is in the whole area of cognition

  8. Agile Port and High Speed Ship Technologies

    DTIC Science & Technology

    2009-12-31

    Report PNW Agile Port System Demonstration Center for the Commercial Deployment of Transportation Technologies milestone agenda for accomplishing the... report summarizes the results of the remaining three projects in the FY05 program cycle, in particular the PNW Agile Port System Demonstration, a system...the accomplishment of each project and the program objectives. With the submission of this report the FY05 CCDoTT Program is complete. Bibliography

  9. 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

  10. SuperAGILE Services at ASDC

    SciTech Connect

    Preger, B.; Verrecchia, F.; Pittori, C.; Antonelli, L. A.; Giommi, P.; Lazzarotto, F.; Evangelista, Y.

    2008-05-22

    The Italian Space Agency Science Data Center (ASDC) is a facility with several responsibilities including support to all the ASI scientific missions as for management and archival of the data, acting as the interface between ASI and the scientific community and providing on-line access to the data hosted. In this poster we describe the services that ASDC provides for SuperAGILE, in particular the ASDC public web pages devoted to the dissemination of SuperAGILE scientific results. SuperAGILE is the X-Ray imager onboard the AGILE mission, and provides the scientific community with orbit-by-orbit information on the observed sources. Crucial source information including position and flux in chosen energy bands will be reported in the SuperAGILE public web page at ASDC. Given their particular interest, another web page will be dedicated entirely to GRBs and other transients, where new event alerts will be notified and where users will find all the available informations on the GRBs detected by SuperAGILE.

  11. 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.

  12. 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.

  13. Steering UNICORE applications with VISIT.

    PubMed

    Eickermann, Thomas; Frings, Wolfgang; Gibbon, Paul; Kirtchakova, Lidia; Mallmann, Daniel; Visser, Anke

    2005-08-15

    The UNICORE (UNiform Interface to COmputing REsources) software provides a Grid infrastructure together with a computing portal for engineers and scientists to access supercomputer centres from anywhere on the Internet. While UNICORE is primarily designed for the submission and control of batch jobs, it is also feasible to establish an on-line connection between an application and the UNICORE user-client. This opens up the possibility of performing on-line visualization and computational steering of applications under UNICORE control while maintaining the security provided by this system. This contribution describes the design of a steering extension to UNICORE based on the steering toolkit VISIT (VISualization Interface Toolkit). VISIT is a lightweight library that supports bidirectional data exchange between visualizations and parallel applications. As an example application, a parallel simulation of a laser-plasma interaction that can be steered by an AVS/Express application is presented.

  14. Loophole-free Quantum Steering

    NASA Astrophysics Data System (ADS)

    Ramelow, Sven; Wittmann, Bernhard; Steinlechner, Fabian; Langford, Nathan K.; Brunner, Nicolas; Wiseman, Howard; Ursin, Rupert; Zeilinger, Anton

    2012-02-01

    Experiments testing quantum mechanics have provided increasing evidence against local realistic theories. However, a conclusive test that simultaneously closes all major loopholes (the locality, freedom-of-choice, and detection loopholes) remains an open challenge. An important class of local realistic theories can be tested with the concept of ``steering.'' Schr"odinger introduced this term for entanglement seemingly allowing to remotely steer the state of a distant system [1]. Einstein called this ``spooky action at a distance.'' Steering was recently formalized by deriving steering inequalities allowing experimental tests. Here, we present the first loophole-free steering experiment [2]. We use entangled photons shared between two distant laboratories and close all loopholes by a large separation, ultra-fast switching and quantum random number generation, and high, overall detection efficiency. Beside its foundational importance loop-hole-free steering is relevant for is relevant for device-independent certification of quantum entanglement. [4pt] [1] E. Schr"odinger, Proc. Camb. , Phil. Soc. 31, 553 (1935) [0pt] [2] B. Wittmann, S. Ramelow, F. Steinlechner, N. K. Langford, N. Brunner, H. Wiseman, R. Ursin, A. Zeilinger, arXiv:1111.0760, (2011)

  15. Infinitely variable steering transmission

    SciTech Connect

    Reed, B.O.

    1989-04-04

    A steering transmission is described comprising: first and second drive units each driven at a substantially constant speed for producing respective first and second unidirectional, continuous outputs infinitely variable between a minimum speed and a maximum speed; a first output planetary gear drivingly connected to a first transmission output; a second output planetary gear set drivingly connected to a second transmission output; an input gear set; means interconnecting the first and second output planetary gear sets; means connecting the first drive unit to the first output planetary gear set; means applying the second drive unit output to the second output planetary gear set; means applying a substantially constant speed input to the input gear set; means for selectively conditioning the input gear set to drive the one output planetary gear set at a speed having a first predetermined fixed ratio to the constant speed input, whereby to operate the transmission in one speed range; and means for selectively applying the first drive unit output to second output planetary gear set, whereby to operate the transmission in another speed range different from the one speed range.

  16. 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.

  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. Enterprise Technologies Deployment for Agile Manufacturing

    SciTech Connect

    Neal, R.E.

    1992-11-01

    This report is intended for high-level technical planners who are responsible for planning future developments for their company or Department of Energy/Defense Programs (DOE/DP) facilities. On one hand, the information may be too detailed or contain too much manufacturing technology jargon for a high-level, nontechnical executive, while at the same time an expert in any of the four infrastructure fields (Product Definition/Order Entry, Planning and Scheduling, Shop Floor Management, and Intelligent Manufacturing Systems) will know more than is conveyed here. The purpose is to describe a vision of technology deployment for an agile manufacturing enterprise. According to the 21st Century Manufacturing Enterprise Strategy, the root philosophy of agile manufacturing is that ``competitive advantage in the new systems will belong to agile manufacturing enterprises, capable of responding rapidly to demand for high-quality, highly customized products.`` Such agility will be based on flexible technologies, skilled workers, and flexible management structures which collectively will foster cooperative initiatives in and among companies. The remainder of this report is dedicated to sharpening our vision and to establishing a framework for defining specific project or pre-competitive project goals which will demonstrate agility through technology deployment.

  19. Enterprise Technologies Deployment for Agile Manufacturing

    SciTech Connect

    Neal, R.E.

    1992-11-01

    This report is intended for high-level technical planners who are responsible for planning future developments for their company or Department of Energy/Defense Programs (DOE/DP) facilities. On one hand, the information may be too detailed or contain too much manufacturing technology jargon for a high-level, nontechnical executive, while at the same time an expert in any of the four infrastructure fields (Product Definition/Order Entry, Planning and Scheduling, Shop Floor Management, and Intelligent Manufacturing Systems) will know more than is conveyed here. The purpose is to describe a vision of technology deployment for an agile manufacturing enterprise. According to the 21st Century Manufacturing Enterprise Strategy, the root philosophy of agile manufacturing is that competitive advantage in the new systems will belong to agile manufacturing enterprises, capable of responding rapidly to demand for high-quality, highly customized products.'' Such agility will be based on flexible technologies, skilled workers, and flexible management structures which collectively will foster cooperative initiatives in and among companies. The remainder of this report is dedicated to sharpening our vision and to establishing a framework for defining specific project or pre-competitive project goals which will demonstrate agility through technology deployment.

  20. Use beam steering dipoles to minimize aberrations associated with off-centered transit through the induction bunching module. Design an improved NDCX-I drift compression section to make best use of the new bunching module to optimize planned initial NDCX-I target experiments

    SciTech Connect

    HIFS-VNL; Seidl, Peter; Seidl, P.; Barnard, J.; Bieniosek, F.; Coleman, J.; Grote, D.; Leitner, M.; Gilson, E.; Logan, B.G.; Lund, S.; Lidia, S.; Ni, P.; Ogata, D.; Roy, P.; Waldron, W.; Welch, D.; Wooton, C.

    2008-03-28

    This milestone has been met by: (1) calculating steering solutions and implementing them in the experiment using the three pairs of crossed magnetic dipoles installed in between the matching solenoids, S1-S4. We have demonstrated the ability to center the beam position and angle to<1 mm and<1 mrad upstream of the induction bunching module (IBM) gap, compared to uncorrected beam offsets of several millimeters and milli-radians. (2) Based on LSP and analytic study, the new IBM, which has twice the volt-seconds of our first IBM, should be accompanied by a longer drift compression section in order to achieve a predicted doubling of the energy deposition on future warm-dense matter targets. This will be accomplished by constructing a longer ferro-electric plasma source. (3) Because the bunched current is a function of the longitudinal phase space and emittance of the beam entering the IBM we have characterized the longitudinal phase space with a high-resolution energy analyzer.

  1. 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.

  2. Pluridirectional High-Energy Agile Scanning Electron Radiotherapy (PHASER): Extremely Rapid Treatment for Early Lung Cancer

    DTIC Science & Technology

    2015-09-01

    tissue [4, 5]. Additionally, VHEE radiation therapy could be delivered using pencil beam electromagnetic scanning techniques, eliminating with this...stage lung cancer using rapidly scanned beams from many directions through electromagnetic steering with no mechanical moving parts, referred to as...the-art. In addition, extremely rapid radiation delivery may have a more effective biological impact on tumors for the same radiation dose. We have

  3. 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.

  4. 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.

  5. 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

  6. The Influence of Agility Training on Physiological and Cognitive Performance

    DTIC Science & Technology

    2010-11-01

    training, subjects completed a physical and cognitive battery of serum cortisol, VO2max, vertical jump , reaction time, Illinois Agility Test , body...strong trends toward the agility group improving more than the traditional group on VO2max (p=0.12), vertical jump (p=0.06), Illinois Agility Test ...levels, maximal oxygen uptake, Illinois Agility Test , Makoto reaction time, and vertical jump . The cognitive portion of the testing sessions

  7. 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)

  8. Robot-Assisted Needle Steering

    PubMed Central

    Reed, Kyle B.; Majewicz, Ann; Kallem, Vinutha; Alterovitz, Ron; Goldberg, Ken; Cowan, Noah J.; Okamura, Allison M.

    2012-01-01

    Needle insertion is a critical aspect of many medical treatments, diagnostic methods, and scientific studies, and is considered to be one of the simplest and most minimally invasive medical procedures. Robot-assisted needle steering has the potential to improve the effectiveness of existing medical procedures and enable new ones by allowing increased accuracy through more dexterous control of the needle tip path and acquisition of targets not accessible by straight-line trajectories. In this article, we describe a robot-assisted needle steering system that uses three integrated controllers: a motion planner concerned with guiding the needle around obstacles to a target in a desired plane, a planar controller that maintains the needle in the desired plane, and a torsion compensator that controls the needle tip orientation about the axis of the needle shaft. Experimental results from steering an asymmetric-tip needle in artificial tissue demonstrate the effectiveness of the system and its sensitivity to various environmental and control parameters. In addition, we show an example of needle steering in ex vivo biological tissue to accomplish a clinically relevant task, and highlight challenges of practical needle steering implementation. PMID:23028210

  9. Planning, Estimating, and Monitoring Progress in Agile Systems Development Environments

    DTIC Science & Technology

    2010-04-01

    Jilemanifesto.orgf Nt:JRJ’HRDP GRUMMAN Agile Terminology Term Definition P d B kl R i /U S i b l dro uct ac og equ rements ser tor es to e comp ete Iteration...Marion, McKelvey, & Uhl- Bien . (2007). Leadership Quarterly, 18(4), 298-318. Agile Development Practices Agile Project Management with Scrum Ken Schwaber

  10. High-precision steering of multipleholographic optical traps

    NASA Astrophysics Data System (ADS)

    Schmitz, Christian H. J.; Spatz, Joachim P.; Curtis, Jennifer E.

    2005-10-01

    Locating and steering entire ensembles of microscopic objects has become extremely practical with the emergence of holographic optical tweezers. Application of this technology to single molecule experiments requires great accuracy in the spatial positioning of optical traps. This paper calculates the theoretical position resolution of a single holographic beam, predicting that sub-nanometer resolution is easily achieved. Experimental corroboration of the spatial resolution's inverse dependence on the hologram's number of pixels and phase levels is presented. To at least a nanometer range position resolution, multiple optical tweezers created by complex superposition holograms also follow the theoretical predictions for a single beam.

  11. Bulling among yearling feedlot steers.

    PubMed

    Pierson, R E; Jensen, R; Braddy, P M; Horton, D P; Christie, R M

    1976-09-01

    In a survey to determine the cause of illness and deaths among yearling feedlot cattle, bulling was found to be one of the major problems. During the years 1971-1974, 54,913 (2.88%) steers became bullers and represented an annual loss of around +325,000. Some of the causes of bulling were found to be hormones, either as implants or in the feed. In 1974, from 1,988 necropsies, it was determined that 83 steers died from riding injuries.

  12. 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…

  13. 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.

  14. The Holy Grail of Agile Acquisition

    DTIC Science & Technology

    2010-04-01

    Bestsellers …” [Erwin 2009] Motivation • Despite of Erwin’s recommendation… – Agility seems to be a simple concept and it is commonly perceived as a virtue...osd mil/dapaproject/>. . . Erwin 2009 Erwin, S.I., Washington Pulse, Pentagon Brass: Stay Away From Management Bestsellers , National Defense, August

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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.

  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. 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...

  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 176.814 - Steering systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 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 subsequent inspection for certification the owner or managing operator shall be prepared to test the steering systems...

  4. 46 CFR 115.814 - Steering systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 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 owner or managing operator shall be prepared to test the steering systems of the vessel and make...

  5. 49 CFR 570.7 - Steering systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... binding or jamming in the steering gear mechanism. (d) Alignment. Toe-in and toe-out measurements shall...) Lash (inches) 16 or less 2 18 21/4 20 21/2 22 23/4 (b) Linkage play. Free play in the steering linkage... front or rear tread of the tire exceeds one-quarter inch there is excessive steering linkage play....

  6. 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.

  7. Agile Multi-Function Arrays

    DTIC Science & Technology

    2007-07-01

    provision of law , no person shall be sUbject to any penalty for failing to comply with a collection of information if it does not display a currently...Y. ;,;ar__ia;.;.li...;.o.:..n ,-) __ 1!....:60~dB. (COMA) I !Baseband Gain Vwiutjun I 65 llB I . Amplitude: bllJ4ncc quadrature mixer i < I dB I - - f...proper delays to form the desired beam proceeds as usual. This procedure has been used by the San Diego company , Chaos Telecomm., Inc. , to determine the

  8. Investigating the strategic antecedents of agility in humanitarian logistics.

    PubMed

    L'Hermitte, Cécile; Brooks, Benjamin; Bowles, Marcus; Tatham, Peter H

    2016-12-16

    This study investigates the strategic antecedents of operational agility in humanitarian logistics. It began by identifying the particular actions to be taken at the strategic level of a humanitarian organisation to support field-level agility. Next, quantitative data (n=59) were collected on four strategic-level capabilities (being purposeful, action-focused, collaborative, and learning-oriented) and on operational agility (field responsiveness and flexibility). Using a quantitative analysis, the study tested the relationship between organisational capacity building and operational agility and found that the four strategic-level capabilities are fundamental building blocks of agility. Collectively they account for 52 per cent of the ability of humanitarian logisticians to deal with ongoing changes and disruptions in the field. This study emphasises the need for researchers and practitioners to embrace a broader perspective of agility in humanitarian logistics. In addition, it highlights the inherently strategic nature of agility, the development of which involves focusing simultaneously on multiple drivers.

  9. 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.

  10. 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.

  11. X-36 Tailless Fighter Agility Research Aircraft arrival at Dryden

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The NASA/McDonnell Douglas Corporation (MDC) X-36 Tailless Fighter Agility Research Aircraft is steered to it's hangar at NASA Dryden Flight Research Center, Edwards, California, following arrival on July 2, 1996. The NASA/Boeing X-36 Tailless Fighter Agility Research Aircraft program successfully demonstrated the tailless fighter design using advanced technologies to improve the maneuverability and survivability of possible future fighter aircraft. The program met or exceeded all project goals. For 31 flights during 1997 at the Dryden Flight Research Center, Edwards, California, the project team examined the aircraft's agility at low speed / high angles of attack and at high speed / low angles of attack. The aircraft's speed envelope reached up to 206 knots (234 mph). This aircraft was very stable and maneuverable. It handled very well. The X-36 vehicle was designed to fly without the traditional tail surfaces common on most aircraft. Instead, a canard forward of the wing was used as well as split ailerons and an advanced thrust-vectoring nozzle for directional control. The X-36 was unstable in both pitch and yaw axes, so an advanced, single-channel digital fly-by-wire control system (developed with some commercially available components) was put in place to stabilize the aircraft. Using a video camera mounted in the nose of the aircraft and an onboard microphone, the X-36 was remotely controlled by a pilot in a ground station virtual cockpit. A standard fighter-type head-up display (HUD) and a moving-map representation of the vehicle's position within the range in which it flew provided excellent situational awareness for the pilot. This pilot-in-the-loop approach eliminated the need for expensive and complex autonomous flight control systems and the risks associated with their inability to deal with unknown or unforeseen phenomena in flight. Fully fueled the X-36 prototype weighed approximately 1,250 pounds. It was 19 feet long and three feet high with a

  12. 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

  13. 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

  14. Fall 2014 SEI Research Review Applying Agile Methods to DoD

    DTIC Science & Technology

    2014-10-28

    2014 © 2014 Carnegie Mellon University Agile Defense Adoption Proponents Team (ADAPT) member E-Learning Agile Course Multiple Presentations ... presentations , program committees: GSAW 2014, Agile 2014, Contracts in Agile International Meeting, AFEI/SEI DoD Agile Summit, GAO Working Groups 8

  15. XP Workshop on Agile Product Line Engineering

    NASA Astrophysics Data System (ADS)

    Ghanam, Yaser; Cooper, Kendra; Abrahamsson, Pekka; Maurer, Frank

    Software Product Line Engineering (SPLE) promises to lower the costs of developing individual applications as they heavily reuse existing artifacts. Besides decreasing costs, software reuse achieves faster development and higher quality. Traditionally, SPLE favors big design upfront and employs traditional, heavy weight processes. On the other hand, agile methods have been proposed to rapidly develop high quality software by focusing on producing working code while reducing upfront analysis and design. Combining both paradigms, although is challenging, can yield significant improvements.

  16. 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.

  17. 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.

  18. 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

  19. Extracting quantum coherence via steering

    NASA Astrophysics Data System (ADS)

    Hu, Xueyuan; Fan, Heng

    2016-09-01

    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.

  20. 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.

  1. Rolling and tumbling: status of the SuperAGILE experiment

    NASA Astrophysics Data System (ADS)

    Del Monte, E.; Costa, E.; di Persio, G.; Donnarumma, I.; Evangelista, Y.; Feroci, M.; Lapshov, I.; Lazzarotto, F.; Mastropietro, M.; Morelli, E.; Pacciani, L.; Rapisarda, M.; Rubini, A.; Soffitta, P.; Tavani, M.; Argan, A.; Trois, A.

    2010-07-01

    The SuperAGILE experiment is the hard X-ray monitor of the AGILE mission. It is a 2 x one-dimensional imager, with 6-arcmin angular resolution in the energy range 18 - 60 keV and a field of view in excess of 1 steradian. SuperAGILE is successfully operating in orbit since Summer 2007, providing long-term monitoring of bright sources and prompt detection and localization of gamma-ray bursts. Starting on October 2009 the AGILE mission lost its reaction wheel and the satellite attitude is no longer stabilized. The current mode of operation of the AGILE satellite is a Spinning Mode, around the Sun-pointing direction, with an angular velocity of about 0.8 degree/s (corresponding to 8 times the SuperAGILE point spread function every second). In these new conditions, SuperAGILE continuously scans a much larger fraction of the sky, with much smaller exposure to each region. In this paper we review some of the results of the first 2.5 years of "standard" operation of SuperAGILE, and show how new implementations in the data analysis software allows to continue the hard X-ray sky monitoring by SuperAGILE also in the new attitude conditions.

  2. 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.

  3. 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...

  4. 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...

  5. 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...

  6. 46 CFR 182.610 - Main steering gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 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...

  7. 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...

  8. 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.

  9. Electron beam control using shock-induced density downramp injection

    NASA Astrophysics Data System (ADS)

    Swanson, K.; Tsai, H.-E.; Barber, S.; Lehe, R.; Mao, H.-S.; Steinke, S.; van Tilborg, J.; Geddes, C. G. R.; Leemans, W. P.

    2017-03-01

    In these experiments, we improve the quality of electrons injected along a shock-induced density downramp. We demonstrate that beam ellipticity and steering are influenced by the shock front tilt, and we present simple models to explain these effects. By adjusting the shock front angle, we minimize the beam's off-axis steering and ellipticity, producing high-quality electron beams over a tunable energy range.

  10. 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.

  11. 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.

  12. Correlation steering in the angularly multimode Raman atomic memory

    NASA Astrophysics Data System (ADS)

    Mazelanik, Mateusz; Dąbrowski, Michał; Wasilewski, Wojciech

    2016-09-01

    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. Performing correlations 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 the 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. 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.

  14. 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).

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Development of an agility assessment module for preliminary fighter design

    NASA Technical Reports Server (NTRS)

    Ngan, Angelen; Bauer, Brent; Biezad, Daniel; Hahn, Andrew

    1996-01-01

    A FORTRAN computer program is presented to perform agility analysis on fighter aircraft configurations. This code is one of the modules of the NASA Ames ACSYNT (AirCraft SYNThesis) design code. The background of the agility research in the aircraft industry and a survey of a few agility metrics are discussed. The methodology, techniques, and models developed for the code are presented. FORTRAN programs were developed for two specific metrics, CCT (Combat Cycle Time) and PM (Pointing Margin), as part of the agility module. The validity of the code was evaluated by comparing with existing flight test data. Example trade studies using the agility module along with ACSYNT were conducted using Northrop F-20 Tigershark and McDonnell Douglas F/A-18 Hornet aircraft models. The sensitivity of thrust loading and wing loading on agility criteria were investigated. The module can compare the agility potential between different configurations and has the capability to optimize agility performance in the preliminary design process. This research provides a new and useful design tool for analyzing fighter performance during air combat engagements.

  20. 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

  1. Integrated product definition representation for agile numerical control applications

    SciTech Connect

    Simons, W.R. Jr.; Brooks, S.L.; Kirk, W.J. III; Brown, C.W.

    1994-11-01

    Realization of agile manufacturing capabilities for a virtual enterprise requires the integration of technology, management, and work force into a coordinated, interdependent system. This paper is focused on technology enabling tools for agile manufacturing within a virtual enterprise specifically relating to Numerical Control (N/C) manufacturing activities and product definition requirements for these activities.

  2. 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.

  3. 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.

  4. 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.

  5. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... through the limit of travel in both directions. Feel for binding or jamming in the steering gear mechanism... diameter (inches) Lash (inches) 16 or less 2 18 21/4 20 21/2 22 23/4 (b) Linkage play. Free play in the steering linkage shall not exceed the values shown in Table 3. (1) Inspection procedure. Elevate the...

  6. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... through the limit of travel in both directions. Feel for binding or jamming in the steering gear mechanism... diameter (inches) Lash (inches) 16 or less 2 18 21/4 20 21/2 22 23/4 (b) Linkage play. Free play in the steering linkage shall not exceed the values shown in Table 3. (1) Inspection procedure. Elevate the...

  7. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... through the limit of travel in both directions. Feel for binding or jamming in the steering gear mechanism... diameter (inches) Lash (inches) 16 or less 2 18 21/4 20 21/2 22 23/4 (b) Linkage play. Free play in the steering linkage shall not exceed the values shown in Table 3. (1) Inspection procedure. Elevate the...

  8. 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.

  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. The effect of electronically steering a phased array ultrasound transducer on near-field tissue heating

    PubMed Central

    Payne, Allison; Vyas, Urvi; Todd, Nick; Bever, Joshua de; Christensen, Douglas A.; Parker, Dennis L.

    2011-01-01

    Purpose: This study presents the results obtained from both simulation and experimental techniques that show the effect of mechanically or electronically steering a phased array transducer on proximal tissue heating. Methods: The thermal response of a nine-position raster and a 16-mm diameter circle scanning trajectory executed through both electronic and mechanical scanning was evaluated in computer simulations and experimentally in a homogeneous tissue-mimicking phantom. Simulations were performed using power deposition maps obtained from the hybrid angular spectrum (HAS) method and applying a finite-difference approximation of the Pennes’ bioheat transfer equation for the experimentally used transducer and also for a fully sampled transducer to demonstrate the effect of acoustic window, ultrasound beam overlap and grating lobe clutter on near-field heating. Results: Both simulation and experimental results show that electronically steering the ultrasound beam for the two trajectories using the 256-element phased array significantly increases the thermal dose deposited in the near-field tissues when compared with the same treatment executed through mechanical steering only. In addition, the individual contributions of both beam overlap and grating lobe clutter to the near-field thermal effects were determined through comparing the simulated ultrasound beam patterns and resulting temperature fields from mechanically and electronically steered trajectories using the 256-randomized element phased array transducer to an electronically steered trajectory using a fully sampled transducer with 40 401 phase-adjusted sample points. Conclusions: Three distinctly different three distinctly different transducers were simulated to analyze the tradeoffs of selected transducer design parameters on near-field heating. Careful consideration of design tradeoffs and accurate patient treatment planning combined with thorough monitoring of the near-field tissue temperature will

  11. Reflections on Software Agility and Agile Methods: Challenges, Dilemmas, & the Way Ahead

    DTIC Science & Technology

    2005-05-11

    Mellon University 10 Research Team Richard Baskerville and Balasubramanian Ramesh Department of Computer Information Systems, Georgia State University...University 38 References Agile Manifesto. http://agilemanifesto.org/ Baskerville , R., Pries-Heje, J., Levine, L., & Ramesh, B. (2005). The high speed...balancing game: How software companies cope with Internet speed. Scandinavian Journal of Information Systems 16, 11-54. Baskerville , R., Levine, L

  12. 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.

  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. Development of a low-cost, low micro-vibration CMG for small agile satellite applications

    NASA Astrophysics Data System (ADS)

    Kawak, B. J.

    2017-02-01

    The agility of the spacecraft which refers to the spacecraft's ability to execute fast and accurate manoeuvers within a fixed period of time, is a key satellite parameter. The spacecraft' s agility is directly proportional to the spacecraft actuators' output torque. For high torque inertial actuators (>0.5 Nm), Control Moment Gyroscope (CMG) exhibits better performances in terms of mass and electrical power consumption than reaction wheels. However, in addition to the complex steering law required to avoid CMG singularities, one of the reasons why CMGs are not widely used is also due to their high micro-vibration emission which may interfere and disrupt the spacecraft' s sensitive instruments such as optical payloads. In this paper, an innovative two-stage viscoelastic isolation system has been designed and implemented in a new low micro-vibration CMG prototype. The first stage of the damping system acts at bearing level to attenuate the possible shock vibrations while the second stage acts at mechanism level to attenuate the structural resonances and motor noise. The developed CMG enables to combine high actuator output torque with a low micro-vibration signature. The viscoelastic damping system is cost effective as it is a fully passive system which requires no thermal control and no electronics. Furthermore, the attenuation provided by this innovative two stage damping system can reach a slope up to -80 dB/dec which leads to a Mini-CMG micro-vibration signature lower than similar output torque reaction wheels not equipped with a damping system.

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

    PubMed

    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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Joint measurability and temporal steering [Invited

    NASA Astrophysics Data System (ADS)

    Karthik, H. S.; Prabhu Tej, J.; Usha Devi, A. R.; Rajagopal, A. K.

    2015-04-01

    Quintino et. al. (Phys. Rev. Lett. 113, 160402 (2014)) and Uola et. al. (Phys. Rev. Lett. 113, 160403 (2014)) have recently established an intrinsic relation between non-joint measurability and Einstein-Podolsky- Rosen steering. They showed that a set of measurements is incompatible (i.e., not jointly measurable) if and only if it can be used for the demonstration of steering. In this paper, we prove the temporal analog of this result viz., a set of measurements are incompatible if and only if it exhibits temporal steering.

  1. 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...

  2. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  3. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  4. 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...

  5. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  6. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  7. 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...

  8. 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...

  9. 46 CFR 58.25-20 - Piping for steering gear.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Piping for steering gear. 58.25-20 Section 58.25-20... MACHINERY AND RELATED SYSTEMS Steering Gear § 58.25-20 Piping for steering gear. (a) Pressure piping must... the hydraulic system can be readily recharged from within the steering-gear compartment and must...

  10. Needle steering for robot-assisted insertion into soft tissue: A survey

    NASA Astrophysics Data System (ADS)

    Gao, Dedong; Lei, Yong; Zheng, Haojun

    2012-07-01

    Needle insertion is a common surgical procedure used in diagnosis and treatment. The needle steering technologies make continuous developments in theoretical and practical aspects along with the in-depth research on needle insertion. It is necessary to summarize and analyze the existing results to promote the future development of theories and applications of needle insertion. Thus, a survey of the state of the art of research is presented on algorithms of needle steering techniques, the surgical robots and devices. Based on the analysis of the needle insertion procedure, the concept of needle steering is defined as a kinematics problem, which is to place the needle at the target and avoid the obstacles. The needle steering techniques, including the artificial potential field method and the nonholonomic model, are introduced to control the needles for improving the accuracy. Based on the quasi-static thinking, the virtual spring model and the cantilever-beam model are developed to calculate the amount of needle deflection and generate the needle path. The phantoms instead of the real tissue are used to verify the models mentioned in most of the experimentations. For the desired needle trajectories, the image-guided robotic devices and some novel needles are presented to achieve the needle steering. Finally, the challenges are provided involving the controllability of the long flexible needle and the properties of soft tissue. The results and investigations can be used for further study on the precision and accuracy of needle insertion.

  11. 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.

  12. NetSim-Steer: A Runtime Steering Framework for Network Simulators

    SciTech Connect

    Ciraci, Selim; Akyol, Bora A.

    2012-08-07

    This paper presents NetSim-Steer, a runtime steering framework for network simulators. With this framework, users can specify execution constraints for the network protocols and network models. In addition to this, users can implement steering rules to be executed when a constraint is violated. These rules allows users to alter the parameters of the protocols/models during the simulation so that they stay within the boundaries of the constraints.

  13. NetSim Steer: A Runtime Steering Framework for Network Simulators

    SciTech Connect

    Ciraci, Selim; Akyol, Bora A.

    2012-08-09

    This paper presents NetSim-Steer, a runtime steering framework for network simulators. With this framework, users can specify execution constraints for the network protocols and network models. In addition to this, users can implement steering rules to be executed when a constraint is violated. These rules allows users to alter the parameters of the protocols/models during the simulation so that they stay within the boundaries of the constraints.

  14. 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}

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

    PubMed

    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 mum in a periodically poled lithium niobate (PPLN) optical parametric oscillator (OPO). Rapid tuning over 400 cm(-1) with random wavelength accessibility is achieved by rotation of the pump beam angle by no more than 24 mrad 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-mum 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.

  16. 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.

  17. CCCT - NCTN Steering Committees - Clinical Imaging

    Cancer.gov

    The Clinical Imaging Steering Committee serves as a forum for the extramural imaging and oncology communities to provide strategic input to the NCI regarding its significant investment in imaging activities in clinical trials.

  18. CCCT - NCTN Steering Committees - Gynecologic Cancers

    Cancer.gov

    The Gynecologic Cancers Steering Committee evaluates and prioritizes concepts for phase 2 and 3 clinical trials in adult gynecologic cancers. The GCSC is also intent on fostering collaboration with international groups and institutions conducting trials.

  19. CCCT - NCORP Cancer Control Steering Committees

    Cancer.gov

    The National Community Oncology Research Program (NCORP) Steering Committees review concepts for clinical trials to control cancer symptoms and cancer treatment side effects, and concepts for studies of cancer care delivery.

  20. 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.

  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. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Agile Software Development in Defense Acquisition: A Mission Assurance Perspective

    DTIC Science & Technology

    2012-03-23

    AEROSPACE REPORT NO ATR -2012(9010)-2 Agile Software Development in Defense Acquisition - A Mission Assurance Perspective March 23, 2012 Peter...release; distribution unlimited. aoUc£23>o;r7 AEROSPACE REPORT NO ATR -2012(9010)-2 Agile Software Development in Defense Acquisition - A Mission...Engineering and Technology Group Approved for public release; distribution unlimited. (A\\ AEROSPACE ^•^ Aautoff $m MK*I? taH AEROSPACE REPORT NO ATR

  8. Coaching for Better (Software) Buying Power in an Agile World

    DTIC Science & Technology

    2013-06-01

    professionals carefully to consider incorporation of agile methodologies into the set of acquisition tools at their disposal. This transformation is not...believes that DevOps , the process of warfighters and developers work- ing together throughout the project, is superior to volumes of detailed...Professionalism of the Total Acquisition Workforce The DoD needs to invest in training the acquisition workforce in agile methodologies to add tools that

  9. Spectroscopic Investigation of Materials for Frequency Agile Laser Systems.

    DTIC Science & Technology

    1985-01-01

    fluorescence spectra and lifetimes of divalent Rh, Ru, Pt, and Ir ions in alkali halide crystals are measured using pulsed nitrogen laser excitation...AD-Ai5t 73t SPECTROSCOPIC INVESTIGRTION OF MATERIALS FOR FREQUENCY t/ AGILE LASER SYSTEMS(U) OKLAHOMA STATE UNIV STILLWATER DEPT OF PHYSICS R C...INVESTIGATION OF MATERIALS FOR FREQUENCY AGILE LASER SYSTEMS Richard C. Powell, Ph.D. Principal Investigator Department of Physics OKLAHOMA STATE UNIVERSITY

  10. Addressing the Barriers to Agile Development in DoD

    DTIC Science & Technology

    2015-05-01

    acquisition development  IT programs are subject to extensive documentation, reviews, and oversight that inhibits speed and agility needed for IT  Major...Based on Program, Ops, and Technical Risk Structuring an Agile Program  Notional: 6 Month Release with 4-Week Sprints – Continual development...integration, and testing – Monthly demonstration of capabilities to users  Gov’t testers, certifiers, and users involved early and often – Minimizes

  11. Architectural Tactics to Support Rapid and Agile Stability

    DTIC Science & Technology

    2012-05-01

    20 CrossTalk—May/June 2012 RAPID AND AGILE STABILITY • Scrum teams, product development teams, component teams, or feature teams spend almost...and individuals in the roles of Scrum master, developer, project manager, and architect on projects from organizations that develop embedded real...agile stability. Using Scrum , 25 teams participated in the develop- ment effort. Some of the teams were colocated; teams (waste), while not evolving

  12. Identification, Characterization, and Evaluation Criteria for Systems Engineering Agile Enablers

    DTIC Science & Technology

    2015-01-16

    monitoring communications in social media groups and websites (such as LinkedIn or Facebook groups associated with the Scaled Agile Framework, Lean... Identification , Characterization, and Evaluation Criteria for Systems Engineering Agile Enablers Technical Report SERC-2015-TR-049-1...currently valid OMB control number 1. REPORT DATE 16 JAN 2015 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Identification

  13. Need for Agility in Security Constraints for Distributed Simulation

    DTIC Science & Technology

    2014-06-01

    Submission to: 19th ICCRTS Title: Need for Agility in Security Constraints for Distributed Simulation (024) Topics: Primary Topic: 5...Modelling and Simulation , Alternates: 4. Experimentation, Metrics and Analysis, and 1. Concepts, Theory, and Policy S. K. Numrich, Ph.D...REPORT TYPE 3. DATES COVERED 00-00-2014 to 00-00-2014 4. TITLE AND SUBTITLE Need for Agility in Security Constraints for Distributed Simulation

  14. Light-Driven Chiral Molecular Motors for Passive Agile Filters

    DTIC Science & Technology

    2014-05-20

    AFRL-OSR-VA-TR-2014-0121 LIGHT-DRIVEN CHIRAL MOLECULAR MOTORS FOR PASSIVE AGILE FILTERS Quan Li KENT STATE UNIV OH Final Report 05/20/2014...Prescribed by ANSI Std. Z39.18 1 FINAL REPORT Title: Light-driven Chiral Molecular Motors for Passive Agile Filters AFOSR...As we proposed originally, the major objective of this project was to synthesize novel light- driven chiral molecular motors or switches targeted

  15. 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.

  16. Oxalate urinary calculi in beef steers.

    PubMed

    Huntington, G B; Emerick, R J

    1984-01-01

    Hereford X Angus steers (10/treatment) were fed 90% concentrate diets containing 0.3%, 0.6%, 0.9%, or 1.2% of calcium for 92 days (trial 1) or 114 days (trial 2). Ground limestone was the supplemental calcium source. At slaughter, 12 of 20 steers fed 0.3% calcium had calculi in the urinary bladder or kidneys, compared with 5 of 20 fed 0.6% calcium, 5 of 20 fed 0.9% calcium, and 4 of 20 fed 1.2% calcium. Analyses of calculi indicated they were oxalate calculi. During the first 49 days of trial 2, plasma hydroxyproline concentrations were higher (P less than 0.10) for steers fed 0.3% calcium than for steers fed higher calcium concentrations. Increased bone resorption in steers fed concentrations of 0.3% calcium, resulting in increased plasma hydroxyproline, an oxalate precursor, was indicated as a source of oxalate in calculi and as an explanation of lower occurrence of calculi in steers fed higher concentrations of calcium.

  17. 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.

  18. Beam dynamics in the SLC final focus system

    SciTech Connect

    Bambade, P.S.

    1987-06-01

    The SLC luminosity is reached by colliding beams focused to about 2 ..mu..m transverse sizes. The Final Focus System (FFS) must enable, beyond its basic optical design, the detection and correction of errors accumulated in the system. In this paper, after summarizing the design, we review the sensitivity to such errors and the ability to correct them. The overall tuning strategy involves three phases: single beam spot minimization, steering the beams in collision and luminosity optimization with beam-beam effects.

  19. Design considerations for high efficiency liquid crystal decentered microlens arrays for steering light.

    PubMed

    Shi, Lei; Shi, Jianru; McManamon, Paul F; Bos, Philip J

    2010-01-20

    We have investigated the causes of low efficiency for optical beam steering devices based on liquid crystal decentered microlens arrays (DLAs). We show that the efficiency is effected by the relative phase of light exiting the individual lenses, the imperfect focusing of small lenses due to diffraction, the aberrations related to off-axis light going through a lens, and the diffraction spreading of light beams going through the DLA structure. A high steering efficiency of over 94.4% is demonstrated by modeling the transmitted light through the DLA with scalar diffraction theory. We also propose modified phase profiles for the lenses that are a function of angle that substantially improve the performance of these types of device over the unmodified profiles.

  20. 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.

  1. Parallel optimization methods for agile manufacturing

    SciTech Connect

    Meza, J.C.; Moen, C.D.; Plantenga, T.D.; Spence, P.A.; Tong, C.H.; Hendrickson, B.A.; Leland, R.W.; Reese, G.M.

    1997-08-01

    The rapid and optimal design of new goods is essential for meeting national objectives in advanced manufacturing. Currently almost all manufacturing procedures involve the determination of some optimal design parameters. This process is iterative in nature and because it is usually done manually it can be expensive and time consuming. This report describes the results of an LDRD, the goal of which was to develop optimization algorithms and software tools that will enable automated design thereby allowing for agile manufacturing. Although the design processes vary across industries, many of the mathematical characteristics of the problems are the same, including large-scale, noisy, and non-differentiable functions with nonlinear constraints. This report describes the development of a common set of optimization tools using object-oriented programming techniques that can be applied to these types of problems. The authors give examples of several applications that are representative of design problems including an inverse scattering problem, a vibration isolation problem, a system identification problem for the correlation of finite element models with test data and the control of a chemical vapor deposition reactor furnace. Because the function evaluations are computationally expensive, they emphasize algorithms that can be adapted to parallel computers.

  2. "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.

  3. 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.

  4. Distributed Beam Former for Distributed-Aperture Electronically Steered Antennas

    DTIC Science & Technology

    2006-11-01

    matrix (Bona et al, 2002; Neron and Delisle, 2005), a printed Rotman lens (Kilic and Dahlstrom, 2005) or other switched time delay system. The...of the two sides facilitates the realization of the transmission line crossings that are inherent in the matrix configuration. Neron and Delisle...Military Vehicle Armor, in USNC/URSI Meeting, Albuquerque, NM. Neron , J-S. and Delisle, G-Y., 2005: Microstrip EHF Butler Matrix Design and

  5. Low-Absorption Liquid Crystals for Infrared Beam Steering

    DTIC Science & Technology

    2013-10-22

    clearing point of 51.5 "C and its melting point is lower than -10 °C due to super-cooling effect . We also measured its transmission spectrum in the...thickness (or effective optical path length) increases, then the absorption will increase exponentially, as Eq. (1) indicates. To improve transmittance... effective mass (m) as: (0 = -yjic/m. (3) As the effective mass increases the vibration frequency decreases, i.e., the absorption band shifts toward a

  6. Low-Absorption Liquid Crystals for Infrared Beam Steering

    DTIC Science & Technology

    2014-10-17

    goals are: ri~0.2 (at-tSilri),*? (at 1 kHz), and absorption coefficient B 5/cm. 15. SUBJECT TERMS Low absorption, MWIR, chlorinated liquid crystals...spectral region of interest by deuteration, fluorination and chlorination ; 2) Employing thin cell gap by choosing a high birefringence liquid crystal...mixture. First, we synthesized several chlorinated terphenyls and made a eutectic mixture showing a low absorption window in the region of 4-5|a.m

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Online parameter estimation for surgical needle steering model.

    PubMed

    Yan, Kai Guo; Podder, Tarun; Xiao, Di; Yu, Yan; Liu, Tien-I; Ling, Keck Voon; Ng, Wan Sing

    2006-01-01

    Estimation of the system parameters, given noisy input/output data, is a major field in control and signal processing. Many different estimation methods have been proposed in recent years. Among various methods, Extended Kalman Filtering (EKF) is very useful for estimating the parameters of a nonlinear and time-varying system. Moreover, it can remove the effects of noises to achieve significantly improved results. Our task here is to estimate the coefficients in a spring-beam-damper needle steering model. This kind of spring-damper model has been adopted by many researchers in studying the tissue deformation. One difficulty in using such model is to estimate the spring and damper coefficients. Here, we proposed an online parameter estimator using EKF to solve this problem. The detailed design is presented in this paper. Computer simulations and physical experiments have revealed that the simulator can estimate the parameters accurately with fast convergent speed and improve the model efficacy.

  12. No-cloning of quantum steering

    NASA Astrophysics Data System (ADS)

    Chiu, Ching-Yi; Lambert, Neill; Liao, Teh-Lu; Nori, Franco; Li, Che-Ming

    2016-06-01

    Einstein-Podolsky-Rosen (EPR) steering allows two parties to verify their entanglement, even if one party’s measurements are untrusted. This concept has not only provided new insights into the nature of non-local spatial correlations in quantum mechanics, but also serves as a resource for one-sided device-independent quantum information tasks. Here, we investigate how EPR steering behaves when one-half of a maximally entangled pair of qudits (multidimensional quantum systems) is cloned by a universal cloning machine. We find that EPR steering, as verified by a criterion based on the mutual information between qudits, can only be found in one of the copy subsystems but not both. We prove that this is also true for the single-system analogue of EPR steering. We find that this restriction, which we term ‘no-cloning of quantum steering’, elucidates the physical reason why steering can be used to secure sources and channels against cloning-based attacks when implementing quantum communication and quantum computation protocols.

  13. Creativity in Agile Systems Development: A Literature Review

    NASA Astrophysics Data System (ADS)

    Conboy, Kieran; Wang, Xiaofeng; Fitzgerald, Brian

    Proponents of agile methods claim that enabling, fostering and driving creativity is the key motivation that differentiates agile methods from their more traditional, beauraucratic counterparts. However, there is very little rigorous research to support this claim. Like most of their predecessors, the development and promotion of these methods has been almost entirely driven by practitioners and consultants, with little objective validation from the research community. This lack of validation is particularly relevant for SMEs, given that many of their project teams typify the environment to which agile methods are most suited i.e. small, co-located teams with diverse, blended skills in unstructured, sometimes even chaotic surroundings. This paper uses creativity theory as a lens to review the current agile method literature to understand exactly how much we know about the extent to which creativity actually occurs in these agile environments. The study reveals many gaps and conflict of opinion in the body of knowledge in its current state and identifies many avenues for further research.

  14. 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

  15. 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)

  16. 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.

  17. Toward effective needle steering in brain tissue.

    PubMed

    Engh, J A; Podnar, G; Kondziolka, D; Riviere, C N

    2006-01-01

    Recent research has exploited the inherent bending of a bevel-tipped needle during insertion, accomplishing steering of the needle by rotating the needle shaft. Combining this technique with the observation that a straight trajectory can be accomplished by spinning the needle at a constant rate during insertion, this paper presents a novel technique for proportional control of the curvature of the trajectory via duty-cycled spinning of the needle. In order to accommodate this technique to very soft tissues such as the brain, several custom needle prototypes have also been designed in order to increase the steering versatility of the system by maximizing the attainable curvature. The paper describes the needle-steering system and the needle prototypes, and presents preliminary results from tests in an artificial brain tissue substitute.

  18. 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.

  19. Steering object-oriented computations with Python

    SciTech Connect

    Yang, T.-Y.B.; Dubois, P.F.; Furnish, G.; Beazley, D.M.

    1996-10-01

    We have described current approaches and future plans for steering C++ application, running Python on parallel platforms, and combination of Tk interface and Python interpreter in steering computations. In addition, there has been significant enhancement in the Gist module. Tk mega widgets has been implemented for a few physics applications. We have also written Python interface to SIJLO, a data storage package used as an interface to a visualization system named MeshTv. Python is being used to control large-scale simulations (molecular dynamics in particular) running on the CM-5 and T3D at LANL as well. A few other code development projects at LLNL are either using or considering Python as their steering shells. In summary, the merits of Python have been appreciated by more and more people in the scientific computation community.

  20. 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.

  1. 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.

  2. Ion Beam Propulsion Study

    NASA Technical Reports Server (NTRS)

    2008-01-01

    The Ion Beam Propulsion Study was a joint high-level study between the Applied Physics Laboratory operated by NASA and ASRC Aerospace at Kennedy Space Center, Florida, and Berkeley Scientific, Berkeley, California. The results were promising and suggested that work should continue if future funding becomes available. The application of ion thrusters for spacecraft propulsion is limited to quite modest ion sources with similarly modest ion beam parameters because of the mass penalty associated with the ion source and its power supply system. Also, the ion source technology has not been able to provide very high-power ion beams. Small ion beam propulsion systems were used with considerable success. Ion propulsion systems brought into practice use an onboard ion source to form an energetic ion beam, typically Xe+ ions, as the propellant. Such systems were used for steering and correction of telecommunication satellites and as the main thruster for the Deep Space 1 demonstration mission. In recent years, "giant" ion sources were developed for the controlled-fusion research effort worldwide, with beam parameters many orders of magnitude greater than the tiny ones of conventional space thruster application. The advent of such huge ion beam sources and the need for advanced propulsion systems for exploration of the solar system suggest a fresh look at ion beam propulsion, now with the giant fusion sources in mind.

  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. 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

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

    NASA Astrophysics Data System (ADS)

    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

    2016-04-01

    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.

  6. 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

  7. 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.

  8. Vibration Isolation, Suppression, Steering, and Pointing (VISSP)

    NASA Technical Reports Server (NTRS)

    Wada, Ben K.; Rahman, Zahidul; Kedikian, Roland

    1996-01-01

    The design of a six degree of freedom flight vibration isolation suppression and steering (VISS) subsystem for a mid-wave infrared camera on the top of a spacecraft is presented. The development of a long stroke piezoelectric, redundant, compact, low stiffness and power efficient actuator is summarized. A subsystem that could be built and validated for flight within 15 months was investigated. The goals of the VISS are 20 dB vibration isolation above 2 Hz, 15 dB vibration suppression of disturbances at about 60 Hz and 120 Hz, and +/- 0.3 deg steering at 2 Hz and 4 Hz.

  9. Design Performance of Front Steering-Type Electron Cyclotron Launcher for ITER

    SciTech Connect

    Takahashi, K.; Imai, T.; Kobayashi, N.; Sakamoto, K.; Kasugai, A.; Hayakawa, A.; Mori, S.; Mohri, K.

    2005-01-15

    The performance of a front steering (FS)-type electron cyclotron launcher designed for the International Thermonuclear Experimental Reactor (ITER) is evaluated with a thermal, electromagnetic, and nuclear analysis of the components; a mechanical test of a spiral tube for the steering mirror; and a rotational test of bearings. The launcher consists of a front shield and a launcher plug where three movable optic mirrors to steer incident multimegawatt radio-frequency beam power, waveguide components, nuclear shields, and vacuum windows are installed. The windows are located behind a closure plate to isolate the transmission lines from the radioactivated circumstance (vacuum vessel). The waveguide lines of the launcher are doglegged to reduce the direct neutron streaming toward the vacuum windows and other components. The maximum stresses on the critical components such as the steering mirror, its cooling tube, and the front shield are less than their allowable stresses. It was also identified that the stress on the launcher, which yielded from electromagnetic force caused by plasma disruption, was a little larger than the criteria, and a modification of the launcher plug structure was necessary. The nuclear analysis result shows that the neutron shield capability of the launcher satisfies the shield criteria of the ITER. It concludes that the design of the FS launcher is generally suitable for application to the ITER.

  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. 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.

  12. The measurement and improvement of the lateral agility of the F-18

    NASA Technical Reports Server (NTRS)

    Eggold, David P.; Valasek, John; Downing, David R.

    1991-01-01

    The effect of vehicle configuration and flight control system performance on the roll agility of a modern fighter aircraft has been investigated. A batch simulation of a generic F-18 Hornet was used to study the roll agility as measured by the time to roll through 90 deg metric. Problems discussed include definition of agility, factors affecting the agility of a vehicle, the development of the time to roll through 90 deg agility metric, and a simulation experiment. It is concluded that the integral of stability or wind axis roll rate should be used as a measure of the roll measure traversed. The time through roll angle 90 deg metric is considered to be a good metric for measuring the transient performance aspect of agility. Roll agility of the F-18, as measured by 90 deg metric, can be improved by 10 to 30 percent. Compatible roll and rudder actuator rates can significantly affect 90 deg agility metric.

  13. 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.

  14. Pathways to agility in the production of neutron generators

    SciTech Connect

    Stoltz, R.E.; Beavis, L.C.; Cutchen, J.T.; Garcia, P.; Gurule, G.A.; Harris, R.N.; McKey, P.C.; Williams, D.W.

    1994-02-01

    This report is the result of a study team commissioned to explore pathways for increased agility in the manufacture of neutron generators. As a part of Sandia`s new responsibility for generator production, the goal of the study was to identify opportunities to reduce costs and increase flexibility in the manufacturing operation. Four parallel approaches (or pathways) were recommended: (1) Know the goal, (2) Use design leverage effectively, (3) Value simplicity, and (4) Configure for flexibility. Agility in neutron generator production can be enhanced if all of these pathways are followed. The key role of the workforce in achieving agility was also noted, with emphasis on ownership, continuous learning, and a supportive environment.

  15. 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.

  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. Project Echo: Antenna Steering System

    NASA Technical Reports Server (NTRS)

    Klahn, R.; Norton, J. A.; Githens, J. A.

    1961-01-01

    The Project Echo communications experiment employed large, steerable,transmitting and receiving antennas at the ground terminals. It was necessary that these highly directional antennas be continuously and accurately pointed at the passing satellite. This paper describes a new type of special purpose data converter for directing narrow-beam communication antennas on the basis of predicted information. The system is capable of converting digital input data into real-time analog voltage commands with a dynamic accuracy of +/- 0.05 degree, which meets the requirements of the present antennas.

  18. A control theory approach to clock steering techniques.

    PubMed

    Farina, Marcello; Galleani, Lorenzo; Tavella, Patrizia; Bittanti, Sergio

    2010-10-01

    Several clock and time scale steering methods have been developed according to different viewpoints by various time laboratories. By resorting to control theory ideas, we propose a common theoretical framework encompassing these methods. A comparison of the most common steering methodologies, namely, the classical steering approach, the GPS bang-bang method, and the linear quadratic Gaussian technique, is carried out. We believe that the use of control theory methods can potentially lead to a better understanding of clock steering algorithms.

  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. The Perfect Process Storm: Integration of CMMI, Agile, and Lean Six Sigma

    DTIC Science & Technology

    2012-12-01

    projects using similar iterative methodologies includ- ing Scrum , Crystal, and Feature-driven Development leading to the meeting of the Agile...1986 Lean Six Sigma (LSS) Late 1990’s Lean Production 1990 CMM 1987 - 2002 CMMI 2002V1.3 2010 Agile XP 1996 Agile Manifesto 2001 Scrum 2001...Business Process Improvement. Most recently his efforts have targeted BPI for 22 Agile SCRUM projects, deploy- ing Project and Process Management

  1. 46 CFR 169.826 - Steering, communications and control.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Steering, communications and control. 169.826 Section... SCHOOL VESSELS Operations Tests, Drills, and Inspections § 169.826 Steering, communications and control. The master shall test the vessel's steering gear, signaling whistle, engine controls,...

  2. 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... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must...

  3. 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... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must...

  4. 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... AIRWORTHINESS STANDARDS: NORMAL, UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES Design and Construction Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must...

  5. 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....

  6. 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....

  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, 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....

  9. 14 CFR 23.745 - Nose/tail wheel steering.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must be demonstrated that its use does not require exceptional pilot skill during takeoff and landing, in crosswinds...) Movement of the pilot's steering control must not interfere with the retraction or extension of the...

  10. 14 CFR 23.745 - Nose/tail wheel steering.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Landing Gear § 23.745 Nose/tail wheel steering. (a) If nose/tail wheel steering is installed, it must be demonstrated that its use does not require exceptional pilot skill during takeoff and landing, in crosswinds...) Movement of the pilot's steering control must not interfere with the retraction or extension of the...

  11. 46 CFR 167.65-25 - Steering gear tests.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Steering Mechanisms for Knowability. 1984 No. 1.

    ERIC Educational Resources Information Center

    Bierschenk, Bernard

    The foundations of knowledge by tradition have been treated analytically, and knowledge has been characterized as a theoretical subject. This article introduces a steering mechanism as the prerequisite for a study of knowledge work and maintenance on empirical grounds. Knowledge is treated synthetically, that is, as something that exists only…

  8. Steering Dynamics in the Dutch Education System

    ERIC Educational Resources Information Center

    Waslander, Sietske; Hooge, Edith; Drewes, Tineke

    2016-01-01

    Based on detailed empirical analyses, we paint a layered picture of emerging steering dynamics. Inspired by Foucault, we put the focus on roles stakeholders define both for themselves and others, how they give sense to policy, how they work together in policy elaboration and implementation, and the subtle and sometimes deceitful function of soft…

  9. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Steering system. 570.60 Section 570.60 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY...) Inspection procedure. Examine fluid reservoir, hoses and pump belts for the conditions indicated....

  10. 49 CFR 570.7 - Steering systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 6 2010-10-01 2010-10-01 false Steering systems. 570.7 Section 570.7 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... in the reservoir. (1) Inspection procedure. Examine fluid reservoir and pump belts for...

  11. 49 CFR 570.7 - Steering systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Steering systems. 570.7 Section 570.7 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY... in the reservoir. (1) Inspection procedure. Examine fluid reservoir and pump belts for...

  12. 49 CFR 570.60 - Steering system.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 6 2011-10-01 2011-10-01 false Steering system. 570.60 Section 570.60 Transportation Other Regulations Relating to Transportation (Continued) NATIONAL HIGHWAY TRAFFIC SAFETY...) Inspection procedure. Examine fluid reservoir, hoses and pump belts for the conditions indicated....

  13. Einstein-Podolsky-Rosen steering inequalities from entropic uncertainty relations

    NASA Astrophysics Data System (ADS)

    Schneeloch, James; Broadbent, Curtis J.; Walborn, Stephen P.; Cavalcanti, Eric G.; Howell, John C.

    2013-06-01

    We use entropic uncertainty relations to formulate inequalities that witness Einstein-Podolsky-Rosen (EPR)-steering correlations in diverse quantum systems. We then use these inequalities to formulate symmetric EPR-steering inequalities using the mutual information. We explore the differing natures of the correlations captured by one-way and symmetric steering inequalities and examine the possibility of exclusive one-way steerability in two-qubit states. Furthermore, we show that steering inequalities can be extended to generalized positive operator-valued measures, and we also derive hybrid steering inequalities between alternate degrees of freedom.

  14. Low Intensity Beam Imaging - Position Sensitive Avalanche Counter

    SciTech Connect

    Mas, J.; Shapira, D; T.A. Lewis

    1998-11-04

    Monitors of this type are mostly intended for the lowest intensity beams at the HRIBF at ORNL. They are used to aid the accelerator operator in focusing and steering the beam and by the experimenters at the focal plane of the spectrometers.

  15. Beam-based Feedback for the NLC Linac

    SciTech Connect

    Hendrickson, L

    2004-07-21

    The NLC linac train-by-train feedback system is designed to stabilize the beam trajectory, but is also a valuable element in the strategy for emittance preservation. New simulations employ improved strategies [1], allowing beam steering to be performed significantly less often than without the feedback system. Additional simulations indicate that the linac feedback can contribute towards successful operation at noisier sites.

  16. Program plan for the MBE-4 multiple beam experiment

    SciTech Connect

    Avery, R.T.

    1985-02-01

    The technical description treats the arrangement of the Injector System (made up of an existing High Voltage Marx Generator, a new Four-beam Source array and a Beam Conditioning Unit for matching and steering) and the Accelerator Apparatus which contains the 24 shaped-pulsed accelerating units. Flexibility in diagnostic capability and physics experiments has been maintained insofar as possible.

  17. 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.

  18. 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.

  19. 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

  20. 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.