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Sample records for 4x4 matrix formalism

  1. Submicrosecond rearrangeable nonblocking silicon-on-insulator thermo-optic 4x4 switch matrix.

    PubMed

    Li, Yuntao; Yu, Jinzhong; Chen, Shaowu; Li, Yanping; Chen, Yuanyuan

    2007-03-15

    A rearrangeable nonblocking silicon-on-insulator-based thermo-optic 4x4 switch matrix is designed and fabricated. A spot-size converter is integrated to reduce the insertion loss, and a new driving circuit is designed to improve the response speed. The insertion loss is less than 10 dB, and the response time is 950 ns. PMID:17308574

  2. Evaluation of 4 X 4 Block Schedule.

    ERIC Educational Resources Information Center

    Mutter, Davida W.; And Others

    1997-01-01

    Describes 4 X 4 block scheduling and its advantages and disadvantages. Examines block scheduling's effects on a Virginia high school's students, teachers, and administration, based on school data and survey results. Most participants preferred block scheduling over the six-period schedule. Grades, attendance, and discipline improved; students…

  3. An Operator Formalism for Unitary Matrix Models

    NASA Astrophysics Data System (ADS)

    Anagnostopoulos, K. N.; Bowick, M. J.; Ishibashi, N.

    We analyze the double scaling limit of unitary matrix models in terms of trigonometric orthogonal polynomials on the circle. In particular we find a compact formulation of the string equation at the kth multicritical point in terms of pseudodifferential operators and a corresponding action principle. We also relate this approach to the mKdV hierarchy which appears in the analysis in terms of conventional orthogonal polynomials on the circle.

  4. Quaternion Formalism for the Intrinsic Transfer Matrix

    NASA Astrophysics Data System (ADS)

    Cretu, Nicolae; Pop, Mihail Ioan; Boer, Attila

    A quaternion formulation is applied to the intrinsic transfer matrix for longitudinal elastic wave propagation through a multilayer medium in order to find the spectral response of a sonic crystal. Resonance conditions and the band structure of the crystal are obtained. The presence of a defect is also analysed. The analysis is carried out theoretically and through simulations. A coupled oscillators model is used to validate the obtained results from a phenomenological point of view. Experimental measurements are carried out for some periodic multilayer arrangements and they are correlated with theory. The obtained spectral response and band structure are essential in characterising the sonic crystal and also in optimising its structure in order to obtain specific passbands and stopbands. The adaptedness of the quaternion formulation to periodic structures and to the inclusion of defects is considered.

  5. Investigations on 4x4 polymer couplers for airborne environment

    NASA Astrophysics Data System (ADS)

    Klotzbuecher, Thomas; Sprzagala, M.; Koch, Anne; Teubner, Ulrich

    2004-09-01

    Due to the potential of high data rates up to several Gb/s, low electromagnetic interference sensitivity and weight reduction capabilities, in future, optical data transmission will become standard in airplanes. The requirements on the necessary optical components that have to be operated in airborne environment in general are extremely high. In addition, airframe manufacturers are interested in low cost components. An example for such an optical component is a star coupler for data distribution, in particular, a device made on base of polymers. The applicability of such 4x4 polymer star couplers under extreme environmental conditions was investigated. The investigations were made at temperatures from -40 to +80 °C and up to 98 % humidity. Different types of housings were tested (polymer, metal, ceramic). It was found that housing of the polymer couplers is required necessarily, since non-housed components exhibit a large insertion loss increase of up to 0.5 dB during temperature variation. Best results were achieved with metal or ceramic housings exhibiting a maximum insertion loss increase of approximately 0.1 dB. However, due to a large difference of thermal expansion coefficients of filling and housing material, respectively, ceramic housings mechanically failed (crack formation) and thus metal housings are first choice. The results were also compared to those achieved for commercial 4x4 multimode couplers made of glass and based on fused bi-conical taper technology.

  6. Experimental test of the Chao matrix formalism for spin dynamics.

    NASA Astrophysics Data System (ADS)

    Morozov, V. S.; Chao, A. W.; Krisch, A. D.; Leonova, M. A.; Raymond, R. S.; Sivers, D. W.; Wong, V. K.; Gebel, R.; Lehrach, A.; Lorentz, B.; Maier, R.; Prasuhn, D.; Schnase, A.; Stockhorst, H.; Hinterberger, F.; Ulbrich, K.

    2007-04-01

    We recently started testing Chao's proposed new matrix formalism for describing the spin dynamics due to a single spin resonance in a stored polarized beam. This formalism seems to be the first generalization of the Froissart-Stora equation since it was published in 1960. It allows one to calculate analytically the polarization's behavior inside a resonance, which is not possible using the Froissart-Stora equation. We recently tested some Chao formalism predictions using a 1.85 GeV/c polarized deuteron beam stored in COSY. We swept an rf dipole's frequency through 200 Hz, at different sweep rates, while varying the distance from the sweep's end frequency to an rf-induced spin resonance's central frequency. We compared our experimental data with the predictions of the Chao formalism and the prediction of a phenomenological Froissart-Stora-based two-fluid model. The Froissart-Stora formula itself can make no prediction inside the resonance. The data seem to support the validity of the Chao formalism. (Supported by the German BMBF Science Ministry.)

  7. 4x4 and 8x8 optical cross connect for optical fiber networks

    NASA Astrophysics Data System (ADS)

    Zickar, Michael; Noell, Wilfried; Marxer, Cornel; de Rooij, Nicolaas F.

    2004-08-01

    We report on a 4x4 optical matrix switch for telecom application. It consists of a 4x4 array of vertical mirrors that have the same pitch as the fibers of commercially available fiber ribbons (250 μm). This compact design enables a parallel assembly to optical components, which simplifies the time consuming and costly process for switches with larger pitch. Additionally, a small pitch leads to a short optical coupling length, which facilitates the integration of a suitable collimation system. However there are physical limitations for optical MEMS in conjunction with assembled micro-optics. The optical beam exiting a collimator diverges, the divergence angle is indirectly proportional to the beam waist and the coupling length increases quadratically. Our calculations show that for a pitch of 250 μm a mirror height of 100 μm is optimal. The mirrors are monolithically etched onto a platform etched during a previous step. No assembly of the mirrors to the actuators is needed. Alignment structures for the optical components are etched during the same step as the mirrors, which lead to self aligned structures. The platform is supported by 150 μm long torsion beams with sub-micron diameter. The electrostatic actuation voltage is given by a separate chip. The mirror moves out of the optical path when the platform is actuated and goes to the switching state if no voltage is applied. The first prototypes have been actuated at 200 V, which agrees with a CoventorWare simulation used for designing the device. Light was successfully switched with a 4x4 OXC. An 8x8 OXC is shown and electrostatically characterized.

  8. 4x4 Individually Addressable InGaAs APD Arrays Optimized for Photon Counting Applications

    NASA Technical Reports Server (NTRS)

    Gu, Y.; Wu, X.; Wu, S.; Choa, F. S.; Yan, F.; Shu, P.; Krainak, M.

    2007-01-01

    InGaAs APDs with improved photon counting characteristics were designed and fabricated and their performance improvements were observed. Following the results, a 4x4 individually addressable APD array was designed, fabricated, and results are reported.

  9. Window type: 4x4 multipaned steel window flanked by 1x4 multipaned ...

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

    Window type: 4x4 multipaned steel window flanked by 1x4 multipaned steel, casements. Concrete stoop, entry overhang and pipe rail detail also illustrated. Building 36, facing northwest - Harbor Hills Housing Project, 26607 Western Avenue, Lomita, Los Angeles County, CA

  10. The Feasibility of 4X4 Block Scheduling in Secondary Schools: A Review of the Literature.

    ERIC Educational Resources Information Center

    Stanley, Anthony; Gifford, Lorna J.

    This paper reviews the literature on 4x4 block scheduling. Studies reveal that the advantages of such scheduling are simplicity, potential for greater student achievement, and reduced disciplinary referrals. Discipline is enhanced through this type of schedule because it decreases the number of times that students are moving in the halls between…

  11. Transfer-matrix approach to three-dimensional bond percolation: An application of Novotny's formalism

    NASA Astrophysics Data System (ADS)

    Nishiyama, Yoshihiro

    2006-01-01

    A transfer-matrix simulation scheme for the three-dimensional (d=3) bond percolation is presented. Our scheme is based on Novotny’s transfer-matrix formalism, which enables us to consider arbitrary (integral) number of sites N constituting a unit of the transfer-matrix slice even for d=3 . Such an arbitrariness allows us to perform systematic finite-size-scaling analysis of the criticality at the percolation threshold. Diagonalizing the transfer matrix for N=4,5,…,10 , we obtain an estimate for the correlation-length critical exponent ν=0.81(5) .

  12. Transfer-matrix approach to three-dimensional bond percolation: an application of Novotny's formalism.

    PubMed

    Nishiyama, Yoshihiro

    2006-01-01

    A transfer-matrix simulation scheme for the three-dimensional (d=3) bond percolation is presented. Our scheme is based on Novotny's transfer-matrix formalism, which enables us to consider arbitrary (integral) number of sites N constituting a unit of the transfer-matrix slice even for d=3. Such an arbitrariness allows us to perform systematic finite-size-scaling analysis of the criticality at the percolation threshold. Diagonalizing the transfer matrix for N=4, 5,..., we obtain an estimate for the correlation-length critical exponent v=0.81(5). PMID:16486223

  13. Science teachers' understanding and use of instructional strategies within the 4 x 4 block schedule

    NASA Astrophysics Data System (ADS)

    Grosshans, Kurt

    The primary purpose of this researcher was to investigate how science teachers engage students under the 4 x 4 block schedule and how the teachers' understanding of how they use instructional strategies influenced their lessons. As an inquiry-based approach has been adopted by the National Science Standards, research has suggested that block scheduling provides more time for teachers to incorporate varied strategies such as inquiry-based and cooperative learning teaching which have philosophical roots in a social constructivist philosophy. This research investigated the questions: What instructional strategies do science teachers use to engage students on the 4 x 4 block schedule? How do science teachers understand their use of instructional strategies? The methodology was qualitative in nature and involved a multiple case study of three high school science teachers at a large rural county high school. Data sources included pre-observation interviews, classroom observations, post-observation interviews, and the collection of documents and artifacts such as lesson plans, student hand-outs, worksheets, laboratory exercises, homework and other document(s) the teacher used to prepare for or implement a lesson. The evidence observed in this study, suggests that the strategies used by these three science teachers remain mostly didactic in nature. Although the teachers reported in the interview phase of this research that they use a wide variety of strategies, what was observed within the 4 x 4 block structure was the use of different didactic strategies, not different holistic strategies. Although the teachers were aware of more holistic strategies such as inquiry-based and cooperative learning, they were not adopted nor adapted within the lesson. The three teachers used strategies that were consistent with their scientific realist views concerning the nature of science. These scientific realist philosophies are antithetical to a social constructivist approach to

  14. Optical 4x4 hitless slicon router for optical networks-on-chip (NoC).

    PubMed

    Sherwood-Droz, Nicolás; Wang, Howard; Chen, Long; Lee, Benjamin G; Biberman, Aleksandr; Bergman, Keren; Lipson, Michal

    2008-09-29

    We demonstrate here a spatially non-blocking optical 4x4 router with a footprint of 0.07 mm(2) for use in future integrated photonic interconnection networks. The device is dynamically switched using thermo-optically tuned silicon microring resonators with a wavelength shift to power ratio of 0.25nm/mW. The design can route four optical inputs to four outputs with individual bandwidths of up to 38.5 GHz. All tested configurations successfully routed a single-wavelength laser and provided a maximum extinction ratio larger than 20 dB. PMID:18825228

  15. Extraction of linear anisotropic parameters using optical coherence tomography and hybrid Mueller matrix formalism.

    PubMed

    Liao, Chia-Chi; Lo, Yu-Lung

    2015-04-20

    A method is proposed for extracting the linear birefringence (LB) and linear dichroism (LD) properties of an anisotropic optical sample using reflection-mode optical coherence tomography (OCT) and a hybrid Mueller matrix formalism. To ensure the accuracy of the extracted parameter values, a method is proposed for calibrating and compensating the polarization distortion effect induced by the beam splitters in the OCT system using a composite quarter-waveplate / half-waveplate / quarter-waveplate structure. The validity of the proposed method is confirmed by extracting the LB and LD properties of a quarter-wave plate and a defective polarizer. To the best of the authors' knowledge, the method proposed in this study represents the first reported attempt to utilize an inverse Mueller matrix formalism and a reflection-mode OCT structure to extract the LB and LD parameters of optically anisotropic samples. PMID:25969104

  16. Quad fourfold (4 X 4) logic unit (LBL No. 21X6421 P-1)

    SciTech Connect

    Mcdonald R.J.; Landis, D.A.; Maier, R.M.; Rude, B.S.; Wozniak, G.J.

    1987-01-01

    A quad fourfold (4 x 4) logic unit has been designed and packaged in a single-width NIM module for use in nuclear and atomic physics experiments. The four inputs of each unit are combined internally to perform logical AND, OR, and VETO functions. A set of eight DIP switches on the front panel select either the input signal or its complement, trigger slope, output pulse duration, and positive or negative logic on the overlap signal. A one-shot multivibrator may be triggered on either the positive or negative-going slope of the overlap signal to form the shaped output. The output width can be adjusted between approx.50 ns and 50 ..mu..sec with two coarse ranges and a twenty-turn potentiometer. An LED attached to the one-shot gives a visual indication of the output rate. 4 figs.

  17. Optical simulation of photovoltaic modules with multiple textured interfaces using the matrix-based formalism OPTOS.

    PubMed

    Tucher, Nico; Eisenlohr, Johannes; Gebrewold, Habtamu; Kiefel, Peter; Höhn, Oliver; Hauser, Hubert; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2016-07-11

    The OPTOS formalism is a matrix-based approach to determine the optical properties of textured optical sheets. It is extended within this work to enable the modelling of systems with an arbitrary number of textured, plane-parallel interfaces. A matrix-based system description is derived that accounts for the optical reflection and transmission interaction between all textured interfaces. Using OPTOS, we calculate reflectance and absorptance of complete photovoltaic module stacks, which consist of encapsulated silicon solar cells featuring textures that operate in different optical regimes. As exemplary systems, solar cells with and without module encapsulation are shown to exhibit a considerable absorptance gain if the random pyramid front side texture is combined with a diffractive rear side grating. A variation of the sunlight's angle of incidence reveals that the grating gain is almost not affected for incoming polar angles up to 60°. Considering as well the good agreement with alternative simulation techniques, OPTOS is demonstrated to be a versatile and efficient method for the optical analysis of photovoltaic modules. PMID:27410896

  18. Utilization of Mueller matrix formalism to obtain optical targets depolarization and polarization properties

    NASA Astrophysics Data System (ADS)

    Le Roy-Brehonnet, F.; Le Jeune, B.

    Polarization is an important property of several physical phenomena such as Rayleigh and Raman ( High intensity Raman Interactions: A. Penzkofer, A. Lauberteau, and W. Kaiser, Progress in Quantum Electronics, 6) (1982) scattering ( Multi-photon Scattering Molecular Spectroscopy, S. Kielich, Progress in Optics, E. Wolf(ed.) North-Holland, Amsterdam) (1983) or fluorescence ( Principles of Fluorescence Spectroscopy, J.R. Lakowicz, Plenum Press) (1986) for example, but also for laser spectral lines ( Laser Lines in Atomic Species, C. S. Willett, Progress in Quantum Electronics, 1) (1969). So, the polarimetric aspect for the propagation in media, such as fibres (Recent progress in fibre optics, G. Cancellieri, F. Chiaraluce, Progress in Quantum Electronics, 18) (1994), the atmosphere and the sea ( Light Scattering by Small Particles (Dover, New York, 1981), must be considered. Following general considerations on the different polarimetric formalisms(Chapter I), this paper first presents a review of present theoretical works on the exploitation of the Mueller matrix (Chapter II). This is followed by original studies of our own, concerning the possibility of extracting polarizing and depolarizing properties of a target characterized by a Mueller matrix (Chapter III). We then study the depolarization effects induced by targets in the Poincare´space (Chapter IV). This depolarization is induced by multiple reflections on rough surfaces or due to partial volume scattering. We have developed an algorithm, based on the knowledge of experimental noise, to classify experimental Mueller matrices according to their polarimetric characteristics. The laser imaging set-up used is described and the method (such as dichroic and birefringent ferrofluid samples) and surfaces (such as sand and other natural targets, dielectric or metallic rough targets).

  19. A Jones matrix formalism for simulating three-dimensional polarized light imaging of brain tissue.

    PubMed

    Menzel, M; Michielsen, K; De Raedt, H; Reckfort, J; Amunts, K; Axer, M

    2015-10-01

    The neuroimaging technique three-dimensional polarized light imaging (3D-PLI) provides a high-resolution reconstruction of nerve fibres in human post-mortem brains. The orientations of the fibres are derived from birefringence measurements of histological brain sections assuming that the nerve fibres—consisting of an axon and a surrounding myelin sheath—are uniaxial birefringent and that the measured optic axis is oriented in the direction of the nerve fibres (macroscopic model). Although experimental studies support this assumption, the molecular structure of the myelin sheath suggests that the birefringence of a nerve fibre can be described more precisely by multiple optic axes oriented radially around the fibre axis (microscopic model). In this paper, we compare the use of the macroscopic and the microscopic model for simulating 3D-PLI by means of the Jones matrix formalism. The simulations show that the macroscopic model ensures a reliable estimation of the fibre orientations as long as the polarimeter does not resolve structures smaller than the diameter of single fibres. In the case of fibre bundles, polarimeters with even higher resolutions can be used without losing reliability. When taking the myelin density into account, the derived fibre orientations are considerably improved. PMID:26446561

  20. Matrix formalism for light propagation and absorption in thick textured optical sheets.

    PubMed

    Eisenlohr, Johannes; Tucher, Nico; Höhn, Oliver; Hauser, Hubert; Peters, Marius; Kiefel, Peter; Goldschmidt, Jan Christoph; Bläsi, Benedikt

    2015-06-01

    In this paper, we introduce a simulation formalism for determining the Optical Properties of Textured Optical Sheets (OPTOS). Our matrix-based method allows for the computationally-efficient calculation of non-coherent light propagation and absorption in thick textured sheets, especially solar cells, featuring different textures on front and rear side that may operate in different optical regimes. Within the simulated system, the angular power distribution is represented by a vector. This light distribution is modified by interaction with the surfaces of the textured sheets, which are described by redistribution matrices. These matrices can be calculated for each individual surface texture with the most appropriate technique. Depending on the feature size of the texture, for example, either ray- or wave-optical methods can be used. The comparison of the simulated absorption in a sheet of silicon for a variety of surface textures, both with the results from other simulation techniques and experimentally measured data, shows very good agreement. To demonstrate the versatility of this newly-developed approach, the absorption in silicon sheets with a large-scale structure (V-grooves) at the front side and a small-scale structure (diffraction grating) at the rear side is calculated. Moreover, with minimal computational effort, a thickness parameter variation is performed. PMID:26072875

  1. Theoretical formulation of Doppler redistribution in scattering polarization within the framework of the velocity-space density matrix formalism

    NASA Astrophysics Data System (ADS)

    Belluzzi, L.; Landi Degl'Innocenti, E.; Trujillo Bueno, J.

    2013-04-01

    Within the framework of the density matrix theory for the generation and transfer of polarized radiation, velocity density matrix correlations represent an important physical aspect that, however, is often neglected in practical applications when adopting the simplifying approximation of complete redistribution on velocity. In this paper, we present an application of the non-LTE problem for polarized radiation taking such correlations into account through the velocity-space density matrix formalism. We consider a two-level atom with infinitely sharp upper and lower levels, and we derive the corresponding statistical equilibrium equations, neglecting the contribution of velocity-changing collisions. Coupling such equations with the radiative transfer equations for polarized radiation, we derive a set of coupled equations for the velocity-dependent source function. This set of equations is then particularized to the case of a plane-parallel atmosphere. The equations presented in this paper provide a complete and solid description of the physics of pure Doppler redistribution, a phenomenon generally described within the framework of the redistribution matrix formalism. The redistribution matrix corresponding to this problem (generally referred to as RI) is derived starting from the statistical equilibrium equations for the velocity-space density matrix and from the radiative transfer equations for polarized radiation, thus showing the equivalence of the two approaches.

  2. Auxiliary matrix formalism for interaction representation transformations, optimal control, and spin relaxation theories

    SciTech Connect

    Goodwin, D. L.; Kuprov, Ilya

    2015-08-28

    Auxiliary matrix exponential method is used to derive simple and numerically efficient general expressions for the following, historically rather cumbersome, and hard to compute, theoretical methods: (1) average Hamiltonian theory following interaction representation transformations; (2) Bloch-Redfield-Wangsness theory of nuclear and electron relaxation; (3) gradient ascent pulse engineering version of quantum optimal control theory. In the context of spin dynamics, the auxiliary matrix exponential method is more efficient than methods based on matrix factorizations and also exhibits more favourable complexity scaling with the dimension of the Hamiltonian matrix.

  3. The physical meaning of scattering matrix singularities in coupled-channel formalisms

    SciTech Connect

    S. Capstick; A. Svarc; L. Tiator; J. Gegelia; M.M. Giannini; E. Santopinto; C. Hanhart; S. Scherer; T.-S.H. Lee; T. Sato; N. Suzuki

    2007-09-04

    The physical meaning of bare and dressed scattering matrix singularities has been investigated. Special attention has been attributed to the role of well known invariance of scattering matrix with respect to the field transformation of the effective Lagrangian. Examples of evaluating bare and dressed quantities in various models are given.

  4. Weak Topological Insulators and Composite Weyl Semimetals: β-Bi_{4}X_{4} (X=Br, I).

    PubMed

    Liu, Cheng-Cheng; Zhou, Jin-Jian; Yao, Yugui; Zhang, Fan

    2016-02-12

    While strong topological insulators (STIs) were experimentally realized soon after they were theoretically predicted, a weak topological insulator (WTI) has yet to be unambiguously confirmed. A major obstacle is the lack of distinct natural cleavage surfaces to test the surface selective hallmark of a WTI. With a new scheme, we discover that β-Bi_{4}X_{4} (X=Br, I), dynamically stable or synthesized before, can be a prototype WTI with two natural cleavage surfaces, where two anisotropic Dirac cones stabilize and annihilate, respectively. We further find four surface-state Lifshitz transitions under charge doping and two bulk topological phase transitions under uniaxial strain. Near the WTI-STI transition, there emerges a novel Weyl semimetal phase, in which the Fermi arcs generically appear at both cleavage surfaces whereas the Fermi circle only appears at one selected surface. PMID:26919004

  5. Energy density matrix formalism for interacting quantum systems: a quantum Monte Carlo study

    SciTech Connect

    Krogel, Jaron T; Kim, Jeongnim; Reboredo, Fernando A

    2014-01-01

    We develop an energy density matrix that parallels the one-body reduced density matrix (1RDM) for many-body quantum systems. Just as the density matrix gives access to the number density and occupation numbers, the energy density matrix yields the energy density and orbital occupation energies. The eigenvectors of the matrix provide a natural orbital partitioning of the energy density while the eigenvalues comprise a single particle energy spectrum obeying a total energy sum rule. For mean-field systems the energy density matrix recovers the exact spectrum. When correlation becomes important, the occupation energies resemble quasiparticle energies in some respects. We explore the occupation energy spectrum for the finite 3D homogeneous electron gas in the metallic regime and an isolated oxygen atom with ground state quantum Monte Carlo techniques imple- mented in the QMCPACK simulation code. The occupation energy spectrum for the homogeneous electron gas can be described by an effective mass below the Fermi level. Above the Fermi level evanescent behavior in the occupation energies is observed in similar fashion to the occupation numbers of the 1RDM. A direct comparison with total energy differences demonstrates a quantita- tive connection between the occupation energies and electron addition and removal energies for the electron gas. For the oxygen atom, the association between the ground state occupation energies and particle addition and removal energies becomes only qualitative. The energy density matrix provides a new avenue for describing energetics with quantum Monte Carlo methods which have traditionally been limited to total energies.

  6. Simulation of coherence selection by pulsed field gradients in liquid-state NMR using an auxiliary matrix formalism

    NASA Astrophysics Data System (ADS)

    Edwards, Luke J.

    2014-03-01

    An algorithm for simulating coherence selection due to a pulse sequence element consisting of two pulsed field gradients separated by a short collection of pulses and delays is introduced. This algorithm involves computation of the matrix exponential of an auxiliary matrix twice the size of the system Liouvillian, a dimensional increase smaller than is required with other known computational methods. Approximations valid for most simulations of liquid-state NMR spectra are involved in the derivation. Diffusion is omitted, but could be treated in an approximate way as a damping over the pulse sequence element. Several NMR pulse sequences using gradients for coherence selection have been implemented, making use of the functionality of Spinach (http://spindynamics.org/Spinach.php). Example simulations testing these implementations are presented, and the extent to which the formal dimensional reduction can lead to a speedup in simulation time discussed. It is found that the previously known methods can be made competitive with the auxiliary matrix method by making use of their embarrassingly parallel nature. Cases where the relative dimensional reduction of the auxiliary matrix method is very large, or where efficient parallelization of the simulation independent of the nature of the algorithm used exists, are found to lead to situations beneficial for the auxiliary matrix algorithm in this comparison.

  7. Statistical model of dephasing in mesoscopic devices introduced in the scattering matrix formalism

    NASA Astrophysics Data System (ADS)

    Pala, Marco G.; Iannaccone, Giuseppe

    2004-06-01

    We propose a phenomenological model of dephasing in mesoscopic transport, based on the introduction of random-phase fluctuations in the computation of the scattering matrix of the system. A Monte Carlo averaging procedure allows us to extract electrical and microscopic device properties. We show that, in this picture, scattering matrix properties enforced by current conservation and time-reversal invariance still hold. In order to assess the validity of the proposed approach, we present simulations of conductance and magnetoconductance of Aharonov-Bohm rings that reproduce the behavior observed in experiments, in particular as far as aspects related to decoherence are concerned.

  8. General formalism for partial spatial coherence in reflection Mueller matrix polarimetry.

    PubMed

    Ossikovski, Razvigor; Hingerl, Kurt

    2016-09-01

    Starting from the first principles, we derive the expressions governing partially coherent Mueller matrix reflection polarimetry on spatially inhomogeneous samples. These are reported both in their general form and in the practically important specific form for two juxtaposed media. PMID:27607968

  9. Vertical comb-drive microscanner with 4x4 array of micromirrors for phase-shifting Mirau microinterferometry

    NASA Astrophysics Data System (ADS)

    Bargiel, Sylwester; Lullin, Justine; Lemoal, Patrice; Perrin, Stéphane; Passilly, Nicolas; Albero, Jorge; Froehly, Luc; Lardet-Vieudrin, Franck; Gorecki, Christophe

    2016-04-01

    In this paper, we present construction, fabrication and characterization of an electrostatic MOEMS vertical microscanner for generation of an optical phase shift in array-type interferometric microsystems. The microscanner employs asymmetric comb-drives for a vertical displacement of a large 4x4 array of reference micromirrors and for in-situ position sensing. The device is designed to be fully compatible with Mirau configuration and with vertical integration strategy. This enables further integration of the device within an "active" multi-channel Mirau micro-interferometer and implementation of the phase shifting interferometry (PSI) technique for imaging applications. The combination of micro-interferometer and PSI is particularly interesting in the swept-source optical coherence tomography, since it allows not only strong size reduction of a system but also improvement of its performance (sensitivity, removal of the image artefacts). The technology of device is based on double-side DRIE of SOI wafer and vapor HF releasing of the suspended platform. In the static mode, the device provides vertical displacement of micromirrors up to 2.8μm (0 - 40V), whereas at resonance (fo=500 Hz), it reaches 0.7 μm for only 1VDC+1VAC. In both operation modes, the measured displacement is much more than required for PSI implementation (352nm peak-to-peak). The presented device is a key component of array-type Mirau micro-interferometer that enables the construction of portable, low-cost interferometric systems, e.g. for in vivo medical diagnostics.

  10. An Existence Proof: Successful Joint Implementation of the IMP Curriculum and a 4 x 4 Block Schedule at a Suburban U.S. High School

    ERIC Educational Resources Information Center

    Kramer, Steven L.; Keller, Regina

    2008-01-01

    This "Brief Report" summarizes results from a study that investigated joint effects of two innovations adopted at a high school in an affluent suburban community in the northeast United States: 4 x 4 block scheduling and the "Standards"-based curriculum, the Interactive Mathematics Program (IMP).

  11. Ginzburg-Landau Free Energy of Crystalline Color Superconductors: A Matrix Formalism from Solid-State Physics

    NASA Astrophysics Data System (ADS)

    Cao, Gao-Qing; He, Lian-Yi

    2015-12-01

    The Ginzburg-Landau (GL) free energy of crystalline color superconductors is important for understanding the nature of the phase transition to the normal quark matter and predicting the preferred crystal structure. So far the GL free energy at zero temperature has only been evaluated up to the sixth order in the condensate. To give quantitative reliable predictions we need to evaluate the higher-order terms. In this work, we present a new derivation of the GL free energy by using the discrete Bloch representation of the fermion field. This derivation introduces a simple matrix formalism without any momentum constraint, which may enable us to calculate the GL free energy to arbitrary order by using a computer. Supported by the National Natural Science Foundation of China under Grant No. 11335005 and the Ministry of Science and Technology under Grant Nos. 2013CB922000 and 2014CB845400, and by the US Department of Energy Topical Collaboration “Neutrinos and Nucleosynthesis in Hot and Dense Matter”

  12. 70 kHz full 4x4 Mueller polarimeter and simultaneous fiber calibration for endoscopic applications.

    PubMed

    Rivet, Sylvain; Bradu, Adrian; Podoleanu, Adrian

    2015-09-01

    A new set-up is proposed to measure the full polarimetric properties of a sample through an optical fiber, paving the way to full-Mueller endoscopic imaging. The technique combines a channeled spectrum polarimeter and an interferometer. This permits high-speed measurement of two Mueller matrices simultaneously. The first matrix characterizes only the fiber while the second characterizes both fiber and sample. The instrument is validated on vacuum, a quarter-wave plate and a linear polarizer for single-point measurements. Insensitivity of the polarimetric measurement to fiber disturbances is proven while manipulating the fiber. PMID:26368471

  13. Matrix formalism of electromagnetic wave propagation through multiple layers in the near-field region: application to the flat panel display.

    PubMed

    Lee, C Y; Lee, D E; Hong, Y K; Shim, J H; Jeong, C K; Joo, J; Zang, D S; Shim, M G; Lee, J J; Cha, J K; Yang, H G

    2003-04-01

    We have developed an electromagnetic (EM) wave propagation theory through a single layer and multiple layers in the near-field and far-field regions, and have constructed a matrix formalism in terms of the boundary conditions of the EM waves. From the shielding efficiency (SE) against EM radiation in the near-field region calculated by using the matrix formalism, we propose that the effect of multiple layers yields enhanced shielding capability compared to a single layer with the same total thickness in conducting layers as the multiple layers. We compare the intensities of an EM wave propagating through glass coated with conducting indium tin oxide (ITO) on one side and on both sides, applying it to the electromagnetic interference (EMI) shielding filter in a flat panel display such as a plasma display panel (PDP). From the measured intensities of EMI noise generated by a PDP loaded with ITO coated glass samples, the two-side coated glass shows a lower intensity of EMI noise compared to the one-side coated glass. The result confirms the enhancement of the SE due to the effect of multiple layers, as expected in the matrix formalism of EM wave propagation in the near-field region. In the far-field region, the two-side coated glass with ITO in multiple layers has a higher SE than the one-side coated glass with ITO, when the total thickness of ITO in both cases is the same. PMID:12786507

  14. General formalism for the efficient calculation of the Hessian matrix of EM data misfit and Hessian-vector products based upon adjoint sources approach

    NASA Astrophysics Data System (ADS)

    Pankratov, Oleg; Kuvshinov, Alexey

    2015-03-01

    3-D electromagnetic (EM) studies of the Earth have advanced significantly over the past decade. Despite a certain success of the 3-D EM inversions of real data sets, the quantitative assessment of the recovered models is still a challenging problem. It is known that one can gain valuable information about model uncertainties from the analysis of Hessian matrix. However, even with modern computational capabilities the calculation of the Hessian matrix based on numerical differentiation is extremely time consuming. Much more efficient way to compute the Hessian matrix is provided by an `adjoint sources' methodology. The computation of Hessian matrix (and Hessian-vector products) using adjoint formulation is now well-established approach, especially in seismic inverse modelling. As for EM inverse modelling we did not find in the literature a description of the approach, which would allow EM researchers to apply this methodology in a straightforward manner to their scenario of interest. In the paper, we present formalism for the efficient calculation of the Hessian matrix using adjoint sources approach. We also show how this technique can be implemented to calculate multiple Hessian-vector products very efficiently. The formalism is general in the sense that it allows to work with responses that arise in EM problem set-ups either with natural- or controlled-source excitations. The formalism allows for various types of parametrization of the 3-D conductivity distribution. Using this methodology one can readily obtain appropriate formulae for the specific sounding methods. To illustrate the concept we provide such formulae for two EM techniques: magnetotellurics and controlled-source sounding with vertical magnetic dipole as a source.

  15. General transfer matrix formalism to calculate DNA–protein–drug binding in gene regulation: application to OR operator of phage λ

    PubMed Central

    Teif, Vladimir B.

    2007-01-01

    The transfer matrix methodology is proposed as a systematic tool for the statistical–mechanical description of DNA–protein–drug binding involved in gene regulation. We show that a genetic system of several cis-regulatory modules is calculable using this method, considering explicitly the site-overlapping, competitive, cooperative binding of regulatory proteins, their multilayer assembly and DNA looping. In the methodological section, the matrix models are solved for the basic types of short- and long-range interactions between DNA-bound proteins, drugs and nucleosomes. We apply the matrix method to gene regulation at the OR operator of phage λ. The transfer matrix formalism allowed the description of the λ-switch at a single-nucleotide resolution, taking into account the effects of a range of inter-protein distances. Our calculations confirm previously established roles of the contact CI–Cro–RNAP interactions. Concerning long-range interactions, we show that while the DNA loop between the OR and OL operators is important at the lysogenic CI concentrations, the interference between the adjacent promoters PR and PRM becomes more important at small CI concentrations. A large change in the expression pattern may arise in this regime due to anticooperative interactions between DNA-bound RNA polymerases. The applicability of the matrix method to more complex systems is discussed. PMID:17526526

  16. Transfer-matrix Formalism for the Calculation of Optical Response in Multilayer Systems: from Coherent to Incoherent Interference

    SciTech Connect

    Troparevski, Claudia; Sabau, Adrian S; Lupini, Andrew R; Zhang, Zhenyu

    2010-01-01

    We present a novel way to account for partially coherent and incoherent interference phenomena in optical multilayer systems via the transfer-matrix method. The transfer matrix method is employed in its usual way via Fresnel coefficients in a 2x2 matrix configuration. The novel feature is that there is no need to use modified Fresnel coefficients or the square of their amplitudes to work in the incoherent limit. The transition from coherent, to partially coherent, to incoherent interference is achieved by introducing a random phase of increasing intensity in the propagating media. This random phase can simulate the effect of defects or impurities in the media. This method provides a general way of dealing with optical multilayer systems, in which coherent and incoherent interference are treated on equal footing.

  17. Interaction of a Guided Wave with a Crack in an Embedded Multilayered Anisotropic Plate: Global Matrix with Laplace Transform Formalism

    NASA Astrophysics Data System (ADS)

    Mora, Pierric; Ducasse, Eric; Deschamps, Marc

    We solve the problem of the interaction of a transient guided elastic wave by a planar crack with an indirect Boundary Element approach in the Laplace domain (t → s). The originality of this work is to use the numerical Green function of the layered plate rather than the analytical Green function of each layer. As a consequence, the BEM matrices are small. To obtain the Green function in the (x,z,s) domain we first solve the equations in the Fourier transform (k,z,s) domain with a Global Matrix approach, and then perform a numerical inverse FFT. Comparisons with finite element show excellent agreement. This approach is fast and low memory consuming for planar defects in arbitrary layered media, and can be extended to arbitrary shapes and boundary conditions for a higher computational cost. It is valid in 3D, however only the 2D case is considered in this work.

  18. Extended ABCD matrix formalism for the description of femtosecond diffraction patterns; application to femtosecond digital in-line holography with anamorphic optical systems.

    PubMed

    Brunel, Marc; Shen, Huanhuan; Coetmellec, Sebastien; Lebrun, Denis

    2012-03-10

    We present a new model to predict diffraction patterns of femtosecond pulses through complex optical systems. The model is based on the extension of an ABCD matrix formalism combined with generalized Huygens-Fresnel transforms (already used in the CW regime) to the femtosecond regime. The model is tested to describe femtosecond digital in-line holography experiments realized in situ through a cylindrical Plexiglas pipe. The model allows us to establish analytical relations that link the holographic reconstruction process to the experimental parameters of the pipe and of the incident beam itself. Simulations and experimental results are in good concordance. Femtosecond digital in-line holography is shown to allow significant coherent noise reduction, and this model will be particularly efficient to describe a wide range of optical geometries. More generally, the model developed can be easily used in any experiment where the knowledge of the precise evolution of femtosecond transverse patterns is required. PMID:22410994

  19. Evaluation of light extraction efficiency for the light-emitting diodes based on the transfer matrix formalism and ray-tracing method

    NASA Astrophysics Data System (ADS)

    Pingbo, An; Li, Wang; Hongxi, Lu; Zhiguo, Yu; Lei, Liu; Xin, Xi; Lixia, Zhao; Junxi, Wang; Jinmin, Li

    2016-06-01

    The internal quantum efficiency (IQE) of the light-emitting diodes can be calculated by the ratio of the external quantum efficiency (EQE) and the light extraction efficiency (LEE). The EQE can be measured experimentally, but the LEE is difficult to calculate due to the complicated LED structures. In this work, a model was established to calculate the LEE by combining the transfer matrix formalism and an in-plane ray tracing method. With the calculated LEE, the IQE was determined and made a good agreement with that obtained by the ABC model and temperature-dependent photoluminescence method. The proposed method makes the determination of the IQE more practical and conventional. Project supported by the National Natural Science Foundation of China (Nos.11574306, 61334009), the China International Science and Technology Cooperation Program (No. 2014DFG62280), and the National High Technology Program of China (No. 2015AA03A101).

  20. Reanalysis of the ground and three torsional excited states of trans-ethyl methyl ether by using an IAM-like tunneling matrix formalism

    NASA Astrophysics Data System (ADS)

    Kobayashi, Kaori; Sakai, Yusuke; Tsunekawa, Shozo; Miyamoto, Taihei; Fujitake, Masaharu; Ohashi, Nobukimi

    2016-03-01

    The trans-ethyl methyl ether has two inequivalent methyl internal rotors and shows tunneling splittings of maximum up to five components. However, the barrier of these two internal rotation potentials were relatively high and the five components were not resolved in the ground state microwave spectra. In this study, well-resolved Fourier transform microwave ground state spectrum was measured for the first time to resolve the five components. The ground state microwave spectra were reanalyzed based on these new measurements and the additional millimeter-wave spectra as well as those studied previously by Fuchs et al. Ninety Fourier transform microwave spectral lines were assigned to 107 transitions in the ground state and 3508 conventional microwave absorption lines were assigned up to Ka = 16 of the ground state, including all 707 lines reported by Fuchs et al. In addition, 10 transitions were observed by the double resonance experiment. They were least-squares-analyzed by the use of an internal axis method (IAM)-like tunneling matrix formalism based on an extended permutation-inversion group theoretical idea. Twenty-two molecular parameters composed of rotational constants, centrifugal distortion constants, internal rotation parameters and internal rotation tunneling parameters were determined for the ground state. The microwave spectra in the three torsionally excited states, that is, the ν28 = 1 C-CH3 torsional state, the ν29 = 1 O-CH3 torsional state and the ν30 = 1 skeletal torsional state, were also reanalyzed by using the IAM-like tunneling matrix formalism and somewhat extended line assignments.

  1. Evaluation of the implementation of the R-matrix formalism with reference to the astrophysically important 18F(p,α)15O reaction

    NASA Astrophysics Data System (ADS)

    Mountford, D. J.; deBoer, R. J.; Descouvemont, P.; Murphy, A. St. J.; Uberseder, E.; Wiescher, M.

    2014-12-01

    Background. The R-Matrix formalism is a crucial tool in the study of nuclear astrophysics reactions, and many codes have been written to implement the relevant mathematics. One such code makes use of Visual Basic macros. A further open-source code, AZURE, written in the FORTRAN programming language is available from the JINA collaboration and a C++ version, AZURE2, has recently become available. Purpose The detailed mathematics and extensive programming required to implement broadly applicable R-Matrix codes make comparisons between different codes highly desirable in order to check for errors. This paper presents a comparison of the three codes based around data and recent results of the astrophysically important 18F(p,α)15O reaction. Methods Using the same analysis techniques as in the work of Mountford et al. parameters are extracted from the two JINA codes, and the resulting cross-sections are compared. This includes both refitting data with each code and making low-energy extrapolations. Results All extracted parameters are shown to be broadly consistent between the three codes and the resulting calculations are in good agreement barring a known low-energy problem in the original AZURE code. Conclusion The three codes are shown to be broadly consistent with each other and equally valid in the study of astrophysical reactions, although one must be careful when considering low lying, narrow resonances which can be problematic when integrating.

  2. Modeling of the whispering gallery mode in microdisk and microgear resonators using a Toeplitz matrix formalism for single-photon source

    NASA Astrophysics Data System (ADS)

    Attia, Moez; Gueddana, Amor; Chatta, Rihab; Morand, Alain

    2013-09-01

    The work presented in this paper develops a new formalism to design microdisks and microgears structures. The main objective is to study the optics and geometrics parameters influence on the microdisks and microgears structures resonance behavior. This study is conducted to choice a resonance structure with height quality factor Q to be associated with Quantum dot to form a single photon source. This new method aims to design resonant structures that are simpler and requires less computing performances than FDTD and Floquet Block methods. This formalism is based on simplifying Fourier transformed and using toeplitz matrix writing. This new writing allows designing all kind of resonance structures with any defect and any modification. In other study we have design a quantum dot emitting a photon at 1550 nm of the fundamental mode, but the quantum dot emits other photons at other wavelengths. The focus of the resonant structure and the quantum dot association is the resonance of the photon at 1550 nm and the elimination of all other photons with others energies. The quantum dot studied in [1] is an InAs/GaAs quantum dot, we design an GaAS microdisk and microgear and we compare the quality factor Q of this two structures and we conclude that the microgear is more appropriated to be associate to the quantum dot and increase the probability P1 to obtain a single photon source at 1550 nm and promotes the obtaining of single photon. The performance improving of the resonant structure is able to increase the success of quantum applications such as quantum gates based on single photon source.

  3. Rethinking Formalisms in Formal Education

    ERIC Educational Resources Information Center

    Nathan, Mitchell J.

    2012-01-01

    I explore a belief about learning and teaching that is commonly held in education and society at large that nonetheless is deeply flawed. The belief asserts that mastery of "formalisms"--specialized representations such as symbolic equations and diagrams with no inherent meaning except that which is established by convention--is prerequisite to…

  4. Research on tunable phase shift induced by piezoelectric transducer in linearly chirped fiber Bragg grating with the V-I transmission matrix formalism

    NASA Astrophysics Data System (ADS)

    Wu, Liangying; Pei, Li; Liu, Chao; Wang, Jianshuai

    2016-05-01

    In this study, the V-I transmission matrix (V-I TM) is proposed to analyze the tunable single phase shift (SPS) and multiple phase shifts (MPS) inserted in a linearly chirped fiber Bragg grating (LCFBG). According to the simulation results, the peaks appear on the transmission spectrum, when the phase shifts are induced in the LCFBG. With the increase of the phase shift, the center wavelength of the peak moves toward long wavelength region. A remarkable degree of bilateral symmetry can be found as characteristic of the depth of peaks. The maximum depth caused by inserted π-shift is the symmetric axis. Moreover, when MPS are inserted simultaneously, the appeared peaks are independent and the variation tendency of each peak is the same with that caused by SPS. The experiment of phase shift induced by a piezoelectric transducer (PZT) verifies the correctness of the simulation, and a narrow bandwidth of 0.028 nm is acquired.

  5. Beyond the fisher-matrix formalism: exact sampling distributions of the maximum-likelihood estimator in gravitational-wave parameter estimation.

    PubMed

    Vallisneri, Michele

    2011-11-01

    Gravitational-wave astronomers often wish to characterize the expected parameter-estimation accuracy of future observations. The Fisher matrix provides a lower bound on the spread of the maximum-likelihood estimator across noise realizations, as well as the leading-order width of the posterior probability, but it is limited to high signal strengths often not realized in practice. By contrast, Monte Carlo Bayesian inference provides the full posterior for any signal strength, but it is too expensive to repeat for a representative set of noises. Here I describe an efficient semianalytical technique to map the exact sampling distribution of the maximum-likelihood estimator across noise realizations, for any signal strength. This technique can be applied to any estimation problem for signals in additive Gaussian noise. PMID:22181593

  6. Chao Formalism & Kondratenko Crossing Tests

    NASA Astrophysics Data System (ADS)

    Raymond, R. S.; Chao, A. W.; Krisch, A. D.; Leonova, M. A.; Morozov, V. S.; Sivers, D. W.; Wong, V. K.; Gebel, R.; Lehrach, A.; Lorentz, B.; Maier, R.; Prasuhn, D.; Schnase, A.; Stockhorst, H.; Hinterberger, F.; Ulbrich, K.; Kondratenko, A. M.

    2007-06-01

    We recently started testing Chao's proposed new matrix formalism for describing the spin dynamics due to a single spin resonance; this seems to be the first generalization of the Froissart-Stora equation since it was published in 1960. The Chao matrix formalism allows one to calculate analytically the polarization's behavior inside a resonance, which is not possible using the Froissart-Stora equation. We recently tested some Chao formalism predictions using a 1.85 GeV/c polarized deuteron beam stored in COSY. We swept an rf dipole's frequency through 200 Hz while varying the distance from the sweep's end frequency to an rf-induced spin resonance's central frequency. While the Froissart-Stora formula can make no prediction in this case, the data seem to support the Chao formalism. We also started investigating the new Kondratenko method to preserve beam polarization during a spin resonance crossing; the method uses 3 rapid changes of the crossing rate near the resonance. With a proper choice of crossing parameters, Kondratenko Crossing may better preserve the polarization than simple fast crossing. We tested Kondratenko's idea using 2.1 GeV/c polarized protons stored in COSY; the frequency of a ferrite rf dipole was swept though an rf-induced spin resonance using Kondratenko's crossing shape. We have not yet observed a significant advantage of Kondratenko Crossing over simple fast crossing. We plan to study it further by choosing better crossing parameters and a smaller momentum spread.

  7. Formal descriptions for formulation.

    PubMed

    This, Hervé

    2007-11-01

    Two formalisms used to describe the physical microstructure and the organization of formulated products are given. The first, called "complex disperse systems formalism" (CDS formalism) is useful for the description of the physical nature of disperse matter. The second, called "non periodical organizational space formalism" (NPOS formalism) has the same operators as the CDS formalism, but different elements; it is useful to describe the arrangement of any objects in space. Both formalisms can be viewed as the same, applied to different orders of magnitude for spatial size. PMID:17875375

  8. Interdependence of Formal Reasoning

    ERIC Educational Resources Information Center

    Berzonsky, Michael D.; And Others

    1975-01-01

    Investigated the intercorrelations among tasks that appear to require Piagetian formal reasoning to determine whether formal reasoning is used selectively or all-pervasively. Subjects were 60 undergraduate females. (SDH)

  9. Fast determination of the optimal rotational matrix for macromolecular superpositions.

    PubMed

    Liu, Pu; Agrafiotis, Dimitris K; Theobald, Douglas L

    2010-05-01

    Finding the rotational matrix that minimizes the sum of squared deviations between two vectors is an important problem in bioinformatics and crystallography. Traditional algorithms involve the inversion or decomposition of a 3 x 3 or 4 x 4 matrix, which can be computationally expensive and numerically unstable in certain cases. Here, we present a simple and robust algorithm to rapidly determine the optimal rotation using a Newton-Raphson quaternion-based method and an adjoint matrix. Our method is at least an order of magnitude more efficient than conventional inversion/decomposition methods, and it should be particularly useful for high-throughput analyses of molecular conformations. PMID:20017124

  10. More than Formal Proof.

    ERIC Educational Resources Information Center

    Hanna, Gila

    1989-01-01

    The origins of the emphasis on formal proof are discussed as well as more recent views. Factors in acceptance of a proof and the social process of acceptance by mathematicians are included. The impact of formal proof on the curriculum and implications for teaching are given. (DC)

  11. Geometry and Formal Linguistics.

    ERIC Educational Resources Information Center

    Huff, George A.

    This paper presents a method of encoding geometric line-drawings in a way which allows sets of such drawings to be interpreted as formal languages. A characterization of certain geometric predicates in terms of their properties as languages is obtained, and techniques usually associated with generative grammars and formal automata are then applied…

  12. Software Formal Inspections Guidebook

    NASA Technical Reports Server (NTRS)

    1993-01-01

    The Software Formal Inspections Guidebook is designed to support the inspection process of software developed by and for NASA. This document provides information on how to implement a recommended and proven method for conducting formal inspections of NASA software. This Guidebook is a companion document to NASA Standard 2202-93, Software Formal Inspections Standard, approved April 1993, which provides the rules, procedures, and specific requirements for conducting software formal inspections. Application of the Formal Inspections Standard is optional to NASA program or project management. In cases where program or project management decide to use the formal inspections method, this Guidebook provides additional information on how to establish and implement the process. The goal of the formal inspections process as documented in the above-mentioned Standard and this Guidebook is to provide a framework and model for an inspection process that will enable the detection and elimination of defects as early as possible in the software life cycle. An ancillary aspect of the formal inspection process incorporates the collection and analysis of inspection data to effect continual improvement in the inspection process and the quality of the software subjected to the process.

  13. Numerically stable secular equation for superlattices via transfer-matrix formalism and application to InAs/In0.23Ga0.77Sb and InAs/In0.3Ga0.7Sb/GaSb superlattices

    NASA Astrophysics Data System (ADS)

    Szmulowicz, Frank

    1998-04-01

    The numerically stable, Hermitian secular equation for superlattices within the envelope-function approximation [F. Szmulowicz, Phys. Rev. B 54, 11 539 (1996)] is derived via the transfer-matrix approach using Burt's boundary conditions. In the process, the tangents-only form of the secular equation is related to an earlier transfer matrix approach [L. R. Ram-Mohan, K. H. Yoo, and R. L. Aggarwal, Phys. Rev. B 38, 6151 (1988)] and extended to structures with an arbitrary number of layers per superlattice period. The formalism is applied to superlattices with two (InAs/In0.23Ga0.77Sb) and three (InAs/In0.3Ga0.7Sb/GaSb) layers per superlattice period, which are of interest for infrared detector and infrared cascade-laser applications, respectively.

  14. CSR-induced emittance growth in achromats: Linear formalism revisited

    NASA Astrophysics Data System (ADS)

    Venturini, M.

    2015-09-01

    We review the R-matrix formalism used to describe Coherent Synchrotron Radiation (CSR)-induced projected emittance growth in electron beam transport lines and establish the connection with a description in terms of the dispersion-invariant function.

  15. Results of an aerodynamic investigation of a space shuttle orbiter/747 carrier flight test configuration to determine separation characteristics utilizing 0.0125-scale models (48-0/AX1318I-1) in the LTV 4 x 4 foot high speed wind tunnel (CA26), volume 1

    NASA Technical Reports Server (NTRS)

    Gillins, R. L.

    1976-01-01

    Results of tests conducted on a 0.0125-scale model of the Space Shuttle Orbiter and a 0.0125-scale model of the 747 CAM configuration in a 4 x 4-foot High Speed Wind Tunnel were presented. Force and moment data were obtained for each vehicle separately at a Mach number of 0.6 and for each vehicle in proximity to the other at Mach numbers of 0.3, 0.5, 0.6 and 0.7. The proximity effects of each vehicle on the other at separation distances (from the mated configuration) ranging from 1.5 feet to 75 feet were presented; 747 Carrier angles of attack from 0 deg to 6 deg and angles of sideslip of 0 deg and -5 deg were tested. Model variables included orbiter elevon, aileron and body flap deflections, orbiter tailcone on and off, and 747 stabilizer and rudder deflections.

  16. Formalizing Probabilistic Safety Claims

    NASA Technical Reports Server (NTRS)

    Herencia-Zapana, Heber; Hagen, George E.; Narkawicz, Anthony J.

    2011-01-01

    A safety claim for a system is a statement that the system, which is subject to hazardous conditions, satisfies a given set of properties. Following work by John Rushby and Bev Littlewood, this paper presents a mathematical framework that can be used to state and formally prove probabilistic safety claims. It also enables hazardous conditions, their uncertainties, and their interactions to be integrated into the safety claim. This framework provides a formal description of the probabilistic composition of an arbitrary number of hazardous conditions and their effects on system behavior. An example is given of a probabilistic safety claim for a conflict detection algorithm for aircraft in a 2D airspace. The motivation for developing this mathematical framework is that it can be used in an automated theorem prover to formally verify safety claims.

  17. Software Formal Inspections Standard

    NASA Technical Reports Server (NTRS)

    1993-01-01

    This Software Formal Inspections Standard (hereinafter referred to as Standard) is applicable to NASA software. This Standard defines the requirements that shall be fulfilled by the software formal inspections process whenever this process is specified for NASA software. The objective of this Standard is to define the requirements for a process that inspects software products to detect and eliminate defects as early as possible in the software life cycle. The process also provides for the collection and analysis of inspection data to improve the inspection process as well as the quality of the software.

  18. Adolescence and Formal Operations

    ERIC Educational Resources Information Center

    Blasi, A.; Hoeffel, E. C.

    1974-01-01

    Analyzes the relationship between the development of formal operations and the development of the adolescent personality, as hypothesized by Inhelder and Piaget. It is suggested that the concepts of possibility and reflectivity have a variety of meanings, and that once these meanings are examined, the logical foundation for the…

  19. Correlates of Formal Reasoning.

    ERIC Educational Resources Information Center

    Linn, Marcia C.; Pulos, Steven

    This study of Piagetian formal reasoning in seventh grade students reports the relationships between four aspects of the ability to control variables in an experiment and the relationships between those four aspects and other constructs. The four aspects of the ability to control variables identified are: (1) set up a controlled experiment, (2)…

  20. Semisymmetric systems: Hermitian formalism

    NASA Astrophysics Data System (ADS)

    Buchdahl, H. A.

    1995-04-01

    The power series representing the characteristic function of a regular semisymmetric system involves four linearly independent rotational invariants XA (A=1,.. .,4) that jointly satisfy a quadratic identity. When the X A are appropriately chosen, this takes the form -(X1)2-(X2 )2-(X3)2+( X4)2=0 . The XA are thus the components of a null vector in a four-dimensional Euclidean space whose metric is gAB: =diag(-1,-1 ,-1,1) . Such a vector is equivalent to a simple 2-spinor xi alpha . The intrinsic presence of a spin vector in the formalism used hitherto suggests that it might be of advantage to replace the latter with an explicit 2-spinor formalism. A way of doing this is examined.

  1. Formalizing the concept of sound.

    SciTech Connect

    Kaper, H. G.; Tipei, S.

    1999-08-03

    The notion of formalized music implies that a musical composition can be described in mathematical terms. In this article we explore some formal aspects of music and propose a framework for an abstract approach.

  2. Formalizing Space Shuttle Software Requirements

    NASA Technical Reports Server (NTRS)

    Crow, Judith; DiVito, Ben L.

    1996-01-01

    This paper describes two case studies in which requirements for new flight-software subsystems on NASA's Space Shuttle were analyzed, one using standard formal specification techniques, the other using state exploration. These applications serve to illustrate three main theses: (1) formal methods can complement conventional requirements analysis processes effectively, (2) formal methods confer benefits regardless of how extensively they are adopted and applied, and (3) formal methods are most effective when they are judiciously tailored to the application.

  3. An envelope function formalism for lattice-matched heterostructures

    NASA Astrophysics Data System (ADS)

    Van de Put, Maarten L.; Vandenberghe, William G.; Magnus, Wim; Sorée, Bart

    2015-08-01

    The envelope function method traditionally employs a single basis set which, in practice, relates to a single material because the k · p matrix elements are generally only known in a particular basis. In this work, we defined a basis function transformation to alleviate this restriction. The transformation is completely described by the known inter-band momentum matrix elements. The resulting envelope function equation can solve the electronic structure in lattice matched heterostructures without resorting to boundary conditions at the interface between materials, while all unit-cell averaged observables can be calculated as with the standard envelope function formalism. In the case of two coupled bands, this heterostructure formalism is equivalent to the standard formalism while taking position dependent matrix elements.

  4. k.p formalism within FLAPW method

    NASA Astrophysics Data System (ADS)

    Shishidou, Tatsuya; Oguchi, Tamio

    2009-03-01

    We provide k.p formalism within the full-potential linearized augmented plane wave (FLAPW) method. Unlike the pure plane waves, the LAPW functions do not behave trivially in moving from k to k+q and their incompleteness as a basis set should be taken into account. Derivatives of the sphere matching coefficients play the key role, for which we find a simple formula. Concrete formula for the k.p matrix elements is derived and numerically tested. Generalized second-order perturbation theory allowing for a degenerate case is presented and the literally-exact electronic band gradients and curvatures are accessible.

  5. Formal verification of AI software

    NASA Technical Reports Server (NTRS)

    Rushby, John; Whitehurst, R. Alan

    1989-01-01

    The application of formal verification techniques to Artificial Intelligence (AI) software, particularly expert systems, is investigated. Constraint satisfaction and model inversion are identified as two formal specification paradigms for different classes of expert systems. A formal definition of consistency is developed, and the notion of approximate semantics is introduced. Examples are given of how these ideas can be applied in both declarative and imperative forms.

  6. Multifractal formalisms of human behavior.

    PubMed

    Ihlen, Espen A F; Vereijken, Beatrix

    2013-08-01

    With the mounting realization that variability is an inevitable part of human behavior comes the need to integrate this phenomenon in concomitant models and theories of motor control. Among other things, this has resulted in a debate throughout the last decades about the origin of variability in behavior, the outcome of which has important implications for motor control theories. To date, a monofractal formalism of variability has been used as the basis for arguing for component- versus interaction-oriented theories of motor control. However, monofractal formalism alone cannot decide between the opposing sides of the debate. The present theoretical overview introduces multifractal formalisms as a necessary extension of the conventional monofractal formalism. In multifractal formalisms, the scale invariance of behavior is numerically defined as a spectrum of scaling exponents, rather than a single average exponent as in the monofractal formalism. Several methods to estimate the multifractal spectrum of scaling exponents - all within two multifractal formalisms called large deviation and Legendre formalism - are introduced and briefly discussed. Furthermore, the multifractal analyses within these two formalisms are applied to several performance tasks to illustrate how explanations of motor control vary with the methods used. The main section of the theoretical overview discusses the implications of multifractal extensions of the component- and interaction-oriented models for existing theories of motor control. PMID:24054900

  7. Formal, Non-Formal and Informal Learning in the Sciences

    ERIC Educational Resources Information Center

    Ainsworth, Heather L.; Eaton, Sarah Elaine

    2010-01-01

    This research report investigates the links between formal, non-formal and informal learning and the differences between them. In particular, the report aims to link these notions of learning to the field of sciences and engineering in Canada and the United States, including professional development of adults working in these fields. It offers…

  8. Unitary formalism for scattering from a hard corrugated wall

    NASA Astrophysics Data System (ADS)

    Brown, G. C.; Celli, V.; Coopersmith, M.; Haller, M.

    1982-07-01

    We obtain two coupled integral equations for the diffraction of waves from a hard corrugated surface. This rearrangement is shown to be equivalent to the integral equation for the scattering amplitude obtained by an application of the Rayleigh method. The formalism presented here, analogous to K-matrix theory, makes the unitarity of the theory apparent at each stage of approximation.

  9. NASA Formal Methods Workshop, 1990

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W. (Compiler)

    1990-01-01

    The workshop brought together researchers involved in the NASA formal methods research effort for detailed technical interchange and provided a mechanism for interaction with representatives from the FAA and the aerospace industry. The workshop also included speakers from industry to debrief the formal methods researchers on the current state of practice in flight critical system design, verification, and certification. The goals were: define and characterize the verification problem for ultra-reliable life critical flight control systems and the current state of practice in industry today; determine the proper role of formal methods in addressing these problems, and assess the state of the art and recent progress toward applying formal methods to this area.

  10. Formalism and functionalism in linguistics.

    PubMed

    Newmeyer, Frederick J

    2010-05-01

    Formalism and functionalism in linguistics are often taken to be diametrically opposed approaches. However, close examination of the relevant phenomena reveals that the two are complementary, rather than being irrevocably in opposition to each other. One can be a formal linguist and a functional linguist at the same time, without there being any contradiction. Copyright © 2010 John Wiley & Sons, Ltd. For further resources related to this article, please visit the WIREs website. PMID:26271372

  11. Complex cobordism and formal groups

    NASA Astrophysics Data System (ADS)

    Buchstaber, Viktor M.

    2012-10-01

    This paper surveys the current state of the theory of cobordism, focusing on geometric and universal properties of complex cobordism, the Landweber-Novikov algebra, and the formal group law of geometric cobordisms. The relationships with K-theory, algebraic cycles, formal group laws, compact Lie group actions on manifolds, toric topology, infinite-dimensional Lie algebras, and nilmanifolds are described. The survey contains key results and open problems. Bibliography: 124 titles.

  12. The Formal Semantics of PVS

    NASA Technical Reports Server (NTRS)

    Owre, Sam; Shankar, Natarajan

    1999-01-01

    A specification language is a medium for expressing what is computed rather than how it is computed. Specification languages share some features with programming languages but are also different in several important ways. For our purpose, a specification language is a logic within which the behavior of computational systems can be formalized. Although a specification can be used to simulate the behavior of such systems, we mainly use specifications to state and prove system properties with mechanical assistance. We present the formal semantics of the specification language of SRI's Prototype Verification System (PVS). This specification language is based on the simply typed lambda calculus. The novelty in PVS is that it contains very expressive language features whose static analysis (e.g., typechecking) requires the assistance of a theorem prover. The formal semantics illuminates several of the design considerations underlying PVS, the interaction between theorem proving and typechecking.

  13. Formal verification of mathematical software

    NASA Technical Reports Server (NTRS)

    Sutherland, D.

    1984-01-01

    Methods are investigated for formally specifying and verifying the correctness of mathematical software (software which uses floating point numbers and arithmetic). Previous work in the field was reviewed. A new model of floating point arithmetic called the asymptotic paradigm was developed and formalized. Two different conceptual approaches to program verification, the classical Verification Condition approach and the more recently developed Programming Logic approach, were adapted to use the asymptotic paradigm. These approaches were then used to verify several programs; the programs chosen were simplified versions of actual mathematical software.

  14. A formalism and computer program for coupled lattices

    SciTech Connect

    Raubenheimer, T.O.

    1989-04-01

    In this paper, a formalism to calculate the lattice functions and emittances of a coupled electron/positron storage ring is presented. The lattice functions are calculated directly from the modal matrix of the betatron transport matrix for the ring. The emittances and damping rates are then calculated from the invariants found in the diagonalized representation. In addition, a computer program is described which uses the formalism to calculate the coupled lattice functions, emittances and damping rates. The program can either reconstruct the closed orbit from BPM data and dipole corrector strengths, or construct an orbit from misalignments entered into the the lattice and then optionally correct the orbit with dipole correctors. The lattice functions, emittances, etc. are then calculated about the resulting closed orbit. 7 refs.

  15. A Formalization of Student Modeling.

    ERIC Educational Resources Information Center

    Danna, Frederic; Sebillot, Pascale

    1997-01-01

    Focuses on student modeling within an Intelligent Tutoring System. Describes three domain-independent properties that the formalism representing student knowledge and the processes synthesizing this knowledge must possess to build accurate student models for second-language learning. Notes when, how, and where hypothetical reasoning mechanisms…

  16. Ambitwistor string theory in the operator formalism

    NASA Astrophysics Data System (ADS)

    Reid-Edwards, R. A.

    2016-06-01

    After a brief overview of the operator formalism for conventional string theory, an operator formalism for ambitwistor string theory is presented. It is shown how tree level supergravity scattering amplitudes are recovered in this formalism. More general applications of this formalism to loop amplitudes and the construction of an ambitwistor string field theory are briefly discussed.

  17. Matrix superpotentials

    NASA Astrophysics Data System (ADS)

    Nikitin, Anatoly G.; Karadzhov, Yuri

    2011-07-01

    We present a collection of matrix-valued shape invariant potentials which give rise to new exactly solvable problems of SUSY quantum mechanics. It includes all irreducible matrix superpotentials of the generic form W=kQ+\\frac{1}{k} R+P, where k is a variable parameter, Q is the unit matrix multiplied by a real-valued function of independent variable x, and P and R are the Hermitian matrices depending on x. In particular, we recover the Pron'ko-Stroganov 'matrix Coulomb potential' and all known scalar shape invariant potentials of SUSY quantum mechanics. In addition, five new shape invariant potentials are presented. Three of them admit a dual shape invariance, i.e. the related Hamiltonians can be factorized using two non-equivalent superpotentials. We find discrete spectrum and eigenvectors for the corresponding Schrödinger equations and prove that these eigenvectors are normalizable.

  18. Formal Analysis of Message Passing

    NASA Astrophysics Data System (ADS)

    Siegel, Stephen F.; Gopalakrishnan, Ganesh

    The message passing paradigm underlies many important families of programs - for instance programs in the area of high performance computing that support science and engineering research. Unfortunately, very few formal methods researchers are involved in developing formal analysis tools and techniques for message passing programs. This paper summarizes research being done in our groups in support of this area, specifically with respect to the Message Passing Interface. We emphasize the need for specialized varieties of many familiar notions such as deadlock detection, race analysis, symmetry analysis, partial order reduction, static analysis and symbolic reasoning support. Since these issues are harbingers of those being faced in multicore programming, the time is ripe to build a critical mass of researchers working in this area.

  19. Notoph gauge theory: Superfield formalism

    NASA Astrophysics Data System (ADS)

    Malik, R. P.

    2011-05-01

    We derive absolutely anticommuting Becchi-Rouet-Stora-Tyutin (BRST) and anti-BRST symmetry transformations for the 4D free Abelian 2-form gauge theory by exploiting the superfield approach to BRST formalism. The antisymmetric tensor gauge field of the above theory was christened as the "notoph" (i.e. the opposite of "photon") gauge field by Ogievetsky and Palubarinov way back in 1966-67. We briefly outline the problems involved in obtaining the absolute anticonimutativity of the (anti-) BRST transformations and their resolution within the framework of geometrical superfield approach to BRST formalism. One of the highlights of our results is the emergence of a Curci-Ferrari type of restriction in the context of 4D Abelian 2-form (notoph) gauge theory which renders the nilpotent (anti-) BRST symmetries of the theory to be absolutely anticommutative in nature.

  20. Formal total synthesis of platencin.

    PubMed

    Varseev, Georgy N; Maier, Martin E

    2009-01-01

    The right bicycle: A concise formal synthesis of platencin was based on an efficient oxygen-mediated palladium-catalyzed cycloalkenylation of 1 to form a bicyclo[3.2.1]octane, and a deoxygenative rearrangement of tosylhydrazone 2 to construct the bicyclo[2.2.2]octane 3. The total yield of the core structure 4 of platencin was 17.5% for 13 steps from a commercially available compound. Ts = p-toluenesulfonyl, TBS = tert-butyldimethylsilyl, Piv = pivaloyl. PMID:19353600

  1. Formal Validation of Aerospace Software

    NASA Astrophysics Data System (ADS)

    Lesens, David; Moy, Yannick; Kanig, Johannes

    2013-08-01

    Any single error in critical software can have catastrophic consequences. Even though failures are usually not advertised, some software bugs have become famous, such as the error in the MIM-104 Patriot. For space systems, experience shows that software errors are a serious concern: more than half of all satellite failures from 2000 to 2003 involved software. To address this concern, this paper addresses the use of formal verification of software developed in Ada.

  2. Formalizing narratives using nested circumscription

    SciTech Connect

    Baral, C.; Gabaldon, A.; Provetti, A.

    1996-12-31

    The representation of narratives of actions and observations is a current issue in Knowledge Representation, where traditional plan-oriented treatments of action seem to fall short. To address narratives, Pinto and Reiter have extended Situation Calculus axioms, Kowalski and Sergot have introduced the Event Calculus in Logic Programming, and Baral et al. have defined the specification language L which allows to express actual and hypothetical situations in a uniform setting. The L entailment relation can formalize several forms of reasoning about actions and change. In this paper we illustrate a translation of L theories into Nested Abnormality Theories, a novel form of circumscription. The proof of soundness and completeness of the translation is the main technical result of the paper, but attention is also devoted to the features of Nested Abnormality Theories to capture commonsense reasoning in general and to clarify which assumptions a logical formalization forces upon a domain. These results also help clarifying the relationship between L and other recent circumscriptive formalization for narratives, such as Miller and Shanahan`s.

  3. Knowledge formalization of intelligent building

    NASA Astrophysics Data System (ADS)

    Žáček, Martin

    2016-06-01

    This article aim is understanding the basic knowledge about an intelligent building. The notion of the intelligent building can be called any building equipped with computer and communication technology, which can automatically respond to internal or external stimuli. The result of the intelligent building is an automated and foreseeing of activities that enable to reduce operating costs and increase comfort. The best way to use the intelligent building is for a low-energy building, a passive building, or for building with high savings. The output of this article is the formalization of basic knowledge of the intelligent building by RDF graph.

  4. On Vasyliunas's equivalent conductivity formalism

    NASA Technical Reports Server (NTRS)

    Pontius, D. H., Jr.

    1992-01-01

    The Vasyliunas's (1972) equivalent conductivity formalism (ECF) for representing the coupling of the ionosphere and the magnetosphere is discussed, and a new, simpler, derivation is presented of the ECF, in which certain of the underlying assumptions and their implications are made transparent. The derivation presented indicates that the only role of the ions in the ECF is to insure quasi-neutrality. It is shown that the ECF is not as robust as usually assumed and that caution must be used to insure that reasonable results are obtained.

  5. 47 CFR 8.12 - Formal Complaints.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Formal Complaints. 8.12 Section 8.12 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRESERVING THE OPEN INTERNET § 8.12 Formal Complaints. Any person may file a formal complaint alleging a violation of the rules in this part....

  6. 47 CFR 8.12 - Formal complaints.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Formal complaints. 8.12 Section 8.12 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRESERVING THE OPEN INTERNET § 8.12 Formal complaints. Any person may file a formal complaint alleging a violation of the rules in this part....

  7. 47 CFR 8.12 - Formal complaints.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Formal complaints. 8.12 Section 8.12 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRESERVING THE OPEN INTERNET § 8.12 Formal complaints. Any person may file a formal complaint alleging a violation of the rules in this part....

  8. 47 CFR 8.12 - Formal complaints.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Formal complaints. 8.12 Section 8.12 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRESERVING THE OPEN INTERNET § 8.12 Formal complaints. Any person may file a formal complaint alleging a violation of the rules in this part....

  9. Sync Matrix

    Energy Science and Technology Software Center (ESTSC)

    2004-12-31

    Sync Matrix provides a graphic display of the relationships among all of the response activities of each jurisdiction. This is accomplished through software that organizes and displays the activities by jurisdiction, function, and time for easy review and analysis. The software can also integrate the displays of multiple jurisdictions to allow examination of the total response.

  10. The Product Operator Formalism: A Physical and Graphical Interpretation

    PubMed Central

    Goldenberg, David P.

    2010-01-01

    The product-operator formalism is the most commonly used tool for describing and designing multidimensional NMR experiments. In spite of its relative simplicity and sound theoretical underpinnings, however, students and practitioners often find it difficult to relate the mathematical manipulations to a physical picture. In an effort to address this pedagogical challenge, the present paper begins with a quantum-mechanical treatment of pure populations of scalar-coupled spin-pairs, rather than the equilibrium population of spin-pairs in different quantum states, which is the usual starting point for treatments based on the density matrix and product operators. In the context of pure populations, the product operators are shown to represent quantum correlations between the nuclei in individual molecules, and a new variation on the classical vector diagram is introduced to represent these correlations. The treatment is extended to mixed populations that begin at thermal equilibrium, and the density matrix is introduced as an efficient means of carrying out quantum calculations for a mixed population. Finally, it is shown that the operators for observable magnetization and correlations can be used as a basis set for the density matrix, providing the formal justification for the widely-used rules of the product-operator treatment. Throughout the discussion, the vector diagrams are used to help maintain a connection between the mathematics and the sometimes subtle physical principles. An electronic supplement created with the Mathematica computer program is used to provide additional mathematical details and the means to carry out further calculations. PMID:21552432

  11. A FORMALISM FOR COVARIANT POLARIZED RADIATIVE TRANSPORT BY RAY TRACING

    SciTech Connect

    Gammie, Charles F.; Leung, Po Kin

    2012-06-20

    We write down a covariant formalism for polarized radiative transfer appropriate for ray tracing through a turbulent plasma. The polarized radiation field is represented by the polarization tensor (coherency matrix) N{sup {alpha}{beta}} {identical_to} (a{sup {alpha}}{sub k} a*{sup {beta}}{sub k}), where a{sub k} is a Fourier coefficient for the vector potential. Using Maxwell's equations, the Liouville-Vlasov equation, and the WKB approximation, we show that the transport equation in vacuo is k{sup {mu}}{nabla}{sub {mu}} N{sup {alpha}{beta}} = 0. We show that this is equivalent to Broderick and Blandford's formalism based on invariant Stokes parameters and a rotation coefficient, and suggest a modification that may reduce truncation error in some situations. Finally, we write down several alternative approaches to integrating the transfer equation.

  12. A Formal Model for Real-Time Parallel Computation

    SciTech Connect

    Hui, Peter SY; Chikkagoudar, Satish

    2012-12-29

    The imposition of real-time constraints on a parallel computing environment--- specifically high-performance, cluster-computing systems--- introduces a variety of challenges with respect to the formal verification of the system's timing properties. In this paper, we briefly motivate the need for such a system, and we introduce an automaton-based method for performing such formal verification. We define the concept of a consistent parallel timing system: a hybrid system consisting of a set of timed automata (specifically, timed Buechi automata as well as a timed variant of standard finite automata), intended to model the timing properties of a well-behaved real-time parallel system. Finally, we give a brief case study to demonstrate the concepts in the paper: a parallel matrix multiplication kernel which operates within provable upper time bounds. We give the algorithm used, a corresponding consistent parallel timing system, and empirical results showing that the system operates under the specified timing constraints.

  13. Heat kernel expansion in the background field formalism

    NASA Astrophysics Data System (ADS)

    Barvinsky, Andrei O.

    2015-06-01

    Heat kernel expansion and background field formalism represent the combination of two calculational methods within the functional approach to quantum field theory. This approach implies construction of generating functionals for matrix elements and expectation values of physical observables. These are functionals of arbitrary external sources or the mean field of a generic configuration -- the background field. Exact calculation of quantum effects on a generic background is impossible. However, a special integral (proper time) representation for the Green's function of the wave operator -- the propagator of the theory -- and its expansion in the ultraviolet and infrared limits of respectively short and late proper time parameter allow one to construct approximations which are valid on generic background fields. Current progress of quantum field theory, its renormalization properties, model building in unification of fundamental physical interactions and QFT applications in high energy physics, gravitation and cosmology critically rely on efficiency of the heat kernel expansion and background field formalism.

  14. Formal Methods at Intel - An Overview

    NASA Technical Reports Server (NTRS)

    Harrison, John

    2010-01-01

    Since the 1990s, Intel has invested heavily in formal methods, which are now deployed in several domains: hardware, software, firmware, protocols etc. Many different formal methods tools and techniques are in active use, including symbolic trajectory evaluation, temporal logic model checking, SMT-style combined decision procedures, and interactive higher-order logic theorem proving. I will try to give a broad overview of some of the formal methods activities taking place at Intel, and describe the challenges of extending formal verification to new areas and of effectively using multiple formal techniques in combination

  15. Formal methods technology transfer: Some lessons learned

    NASA Technical Reports Server (NTRS)

    Hamilton, David

    1992-01-01

    IBM has a long history in the application of formal methods to software development and verification. There have been many successes in the development of methods, tools and training to support formal methods. And formal methods have been very successful on several projects. However, the use of formal methods has not been as widespread as hoped. This presentation summarizes several approaches that have been taken to encourage more widespread use of formal methods, and discusses the results so far. The basic problem is one of technology transfer, which is a very difficult problem. It is even more difficult for formal methods. General problems of technology transfer, especially the transfer of formal methods technology, are also discussed. Finally, some prospects for the future are mentioned.

  16. A Comparison of Participation Patterns in Selected Formal, Non-Formal, and Informal Online Learning Environments

    ERIC Educational Resources Information Center

    Schwier, Richard A.; Seaton, J. X.

    2013-01-01

    Does learner participation vary depending on the learning context? Are there characteristic features of participation evident in formal, non-formal, and informal online learning environments? Six online learning environments were chosen as epitomes of formal, non-formal, and informal learning contexts and compared. Transcripts of online…

  17. On solving for the density matrix

    NASA Astrophysics Data System (ADS)

    Cummings, F. W.

    1985-11-01

    A “generating matrix” formalism is presented which is useful in the solution of a class of time-dependent quantum density matrix problems. Three examples of its use are sketched, giving a unified approach to the solution of the problem of the spontaneous emission of electromagnetic radiation from a single atom in various environments.

  18. Formal modeling of virtual machines

    NASA Technical Reports Server (NTRS)

    Cremers, A. B.; Hibbard, T. N.

    1978-01-01

    Systematic software design can be based on the development of a 'hierarchy of virtual machines', each representing a 'level of abstraction' of the design process. The reported investigation presents the concept of 'data space' as a formal model for virtual machines. The presented model of a data space combines the notions of data type and mathematical machine to express the close interaction between data and control structures which takes place in a virtual machine. One of the main objectives of the investigation is to show that control-independent data type implementation is only of limited usefulness as an isolated tool of program development, and that the representation of data is generally dictated by the control context of a virtual machine. As a second objective, a better understanding is to be developed of virtual machine state structures than was heretofore provided by the view of the state space as a Cartesian product.

  19. Floquet Green function formalism for harmonically driven Hamiltonians

    NASA Astrophysics Data System (ADS)

    Martinez, D. F.

    2003-09-01

    A method is proposed for the calculation of the Floquet-Green function of a general Hamiltonian with harmonic time dependence. We use matrix continued fractions to derive an expression for the 'dynamical effective potential' that can be used to calculate the Floquet-Green function of the system. We demonstrate the formalism for the simple case of a space-periodic (in the tight-binding approximation) Hamiltonian with a defect whose on-site energy changes harmonically with time. We study the local density of states for this system and the behaviour of the localized states as a function of the different parameters that characterize the system.

  20. The distinguishable cluster approach from a screened Coulomb formalism.

    PubMed

    Kats, Daniel

    2016-01-28

    The distinguishable cluster doubles equations have been derived starting from an effective screened Coulomb formalism and a particle-hole symmetric formulation of the Fock matrix. A perturbative triples correction to the distinguishable cluster with singles and doubles (DCSD) has been introduced employing the screened integrals. It is shown that the resulting DCSD(T) method is more accurate than DCSD for reaction energies and is less sensitive to the static correlation than coupled cluster with singles and doubles with a perturbative triples correction. PMID:26827197

  1. Measurement-feedback formalism meets information reservoirs

    NASA Astrophysics Data System (ADS)

    Shiraishi, Naoto; Matsumoto, Takumi; Sagawa, Takahiro

    2016-01-01

    There have been two distinct formalisms of thermodynamics of information: one is the measurement-feedback formalism, which concerns bipartite systems with measurement and feedback processes, and the other is the information reservoir formalism, which considers bit sequences as a thermodynamic fuel. In this paper, we derive a second-law-like inequality by applying the measurement-feedback formalism to information reservoirs, which provides a stronger bound of extractable work than any other known inequality in the same setup. In addition, we demonstrate that the Mandal-Jarzynski model, which is a prominent model of the information reservoir formalism, is equivalent to a model obtained by the contraction of a bipartite system with autonomous measurement and feedback. Our results provide a unified view on the measurement-feedback and the information-reservoir formalisms.

  2. Relativistic Dipole Matrix Element Zeros

    NASA Astrophysics Data System (ADS)

    Lajohn, L. A.; Pratt, R. H.

    2002-05-01

    There is a special class of relativistic high energy dipole matrix element zeros (RZ), whose positions with respect to photon energy ω , only depend on the bound state l quantum number according to ω^0=mc^2/(l_b+1) (independent of primary quantum number n, nuclear charge Z, central potential V and dipole retardation). These RZ only occur in (n,l_b,j_b)arrow (ɛ , l_b+1,j_b) transitions such as ns_1/2arrow ɛ p_1/2; np_3/2arrow ɛ d_3/2: nd_5/2arrow ɛ f_5/2 etc. The nonrelativistic limit of these matrix elements can be established explicitly in the Coulomb case. Within the general matrix element formalism (such as that in [1]); when |κ | is substituted for γ in analytic expressions for matrix elements, the zeros remain, but ω^0 now becomes dependent on n and Z. When the reduction to nonrelativistic form is completed by application of the low energy approximation ω mc^2 mc^2, the zeros disappear. This nonzero behavior was noted in nonrelativistic dipole Coulomb matrix elements by Fano and Cooper [2] and later proven by Oh and Pratt[3]. (J. H. Scofield, Phys. Rev. A 40), 3054 (1989 (U. Fano and J. W. Cooper, Rev. Mod. Phys. 40), 441 (1968). (D. Oh and R. H. Pratt, Phys. Rev. A 34), 2486 (1986); 37, 1524 (1988); 45, 1583 (1992).

  3. Survey of Existing Tools for Formal Verification.

    SciTech Connect

    Punnoose, Ratish J.; Armstrong, Robert C.; Wong, Matthew H.; Jackson, Mayo

    2014-12-01

    Formal methods have come into wide use because of their effectiveness in verifying "safety and security" requirements of digital systems; a set of requirements for which testing is mostly ineffective. Formal methods are routinely used in the design and verification of high-consequence digital systems in industry. This report outlines our work in assessing the capabilities of commercial and open source formal tools and the ways in which they can be leveraged in digital design workflows.

  4. Anyons in the operational formalism

    SciTech Connect

    Neori, Klil H.; Goyal, Philip

    2015-01-13

    The operational formalism to quantum mechanics seeks to base the theory on a firm foundation of physically well-motivated axioms [1]. It has succeeded in deriving the Feynman rules [2] for general quantum systems. Additional elaborations have applied the same logic to the question of identical particles, confirming the so-called Symmetrization Postulate [3]: that the only two options available are fermions and bosons [4, 5]. However, this seems to run counter to results in two-dimensional systems, which allow for anyons, particles with statistics which interpolate between Fermi-Dirac and Bose-Einstein (see [6] for a review). In this talk we will show that the results in two dimensions can be made compatible with the operational results. That is, we will show that anyonic behavior is a result of the topology of the space in two dimensions [7], and does not depend on the particles being identical; but that nevertheless, if the particles are identical, the resulting system is still anyonic.

  5. Anyons in the operational formalism

    NASA Astrophysics Data System (ADS)

    Neori, Klil H.; Goyal, Philip

    2015-01-01

    The operational formalism to quantum mechanics seeks to base the theory on a firm foundation of physically well-motivated axioms [1]. It has succeeded in deriving the Feynman rules [2] for general quantum systems. Additional elaborations have applied the same logic to the question of identical particles, confirming the so-called Symmetrization Postulate [3]: that the only two options available are fermions and bosons [4, 5]. However, this seems to run counter to results in two-dimensional systems, which allow for anyons, particles with statistics which interpolate between Fermi-Dirac and Bose-Einstein (see [6] for a review). In this talk we will show that the results in two dimensions can be made compatible with the operational results. That is, we will show that anyonic behavior is a result of the topology of the space in two dimensions [7], and does not depend on the particles being identical; but that nevertheless, if the particles are identical, the resulting system is still anyonic.

  6. Universal formalism of Fano resonance

    SciTech Connect

    Huang, Liang; Lai, Ying-Cheng; Luo, Hong-Gang; Grebogi, Celso

    2015-01-15

    The phenomenon of Fano resonance is ubiquitous in a large variety of wave scattering systems, where the resonance profile is typically asymmetric. Whether the parameter characterizing the asymmetry should be complex or real is an issue of great experimental interest. Using coherent quantum transport as a paradigm and taking into account of the collective contribution from all available scattering channels, we derive a universal formula for the Fano-resonance profile. We show that our formula bridges naturally the traditional Fano formulas with complex and real asymmetry parameters, indicating that the two types of formulas are fundamentally equivalent (except for an offset). The connection also reveals a clear footprint for the conductance resonance during a dephasing process. Therefore, the emergence of complex asymmetric parameter when fitting with experimental data needs to be properly interpreted. Furthermore, we have provided a theory for the width of the resonance, which relates explicitly the width to the degree of localization of the close-by eigenstates and the corresponding coupling matrices or the self-energies caused by the leads. Our work not only resolves the issue about the nature of the asymmetry parameter, but also provides deeper physical insights into the origin of Fano resonance. Since the only assumption in our treatment is that the transport can be described by the Green’s function formalism, our results are also valid for broad disciplines including scattering problems of electromagnetic waves, acoustics, and seismology.

  7. Third NASA Langley Formal Methods Workshop

    NASA Technical Reports Server (NTRS)

    Holloway, C. Michael (Compiler)

    1995-01-01

    This publication constitutes the proceedings of NASA Langley Research Center's third workshop on the application of formal methods to the design and verification of life-critical systems. This workshop brought together formal methods researchers, industry engineers, and academicians to discuss the potential of NASA-sponsored formal methods and to investigate new opportunities for applying these methods to industry problems. contained herein are copies of the material presented at the workshop, summaries of many of the presentations, a complete list of attendees, and a detailed summary of the Langley formal methods program. Much of this material is available electronically through the World-Wide Web via the following URL.

  8. Formal Methods for Life-Critical Software

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.; Johnson, Sally C.

    1993-01-01

    The use of computer software in life-critical applications, such as for civil air transports, demands the use of rigorous formal mathematical verification procedures. This paper demonstrates how to apply formal methods to the development and verification of software by leading the reader step-by-step through requirements analysis, design, implementation, and verification of an electronic phone book application. The current maturity and limitations of formal methods tools and techniques are then discussed, and a number of examples of the successful use of formal methods by industry are cited.

  9. The Second NASA Formal Methods Workshop 1992

    NASA Technical Reports Server (NTRS)

    Johnson, Sally C. (Compiler); Holloway, C. Michael (Compiler); Butler, Ricky W. (Compiler)

    1992-01-01

    The primary goal of the workshop was to bring together formal methods researchers and aerospace industry engineers to investigate new opportunities for applying formal methods to aerospace problems. The first part of the workshop was tutorial in nature. The second part of the workshop explored the potential of formal methods to address current aerospace design and verification problems. The third part of the workshop involved on-line demonstrations of state-of-the-art formal verification tools. Also, a detailed survey was filled in by the attendees; the results of the survey are compiled.

  10. 14 CFR 302.404 - Formal complaints.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Formal complaints. 302.404 Section 302.404 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) PROCEDURAL... business or the ends of justice. (e) Service. A formal complaint, and any amendments thereto, shall...

  11. Formal Moral Education and Individual Moral Development.

    ERIC Educational Resources Information Center

    Friend, Gary Gene

    This report provides a summarization of a study designed to determine if there is a significant relationship between formal religious education and the moral judgment development of college students, and after controlling for formal religious education, to see if there was also a significant relationship between the educational environment or…

  12. Male-Female Differences in Formal Thought.

    ERIC Educational Resources Information Center

    Linn, Marcia C.

    Two studies were conducted to clarify the influence of experiences and aptitudes on male-female differences in formal thought. Participants were 788 seventh-, ninth-, and eleventh-graders in three school districts differing in location, socioeconomic composition, and course offerings. Formal thought was measured with tasks involving proportional…

  13. Does (In)Formal Learning Enhance Employability?

    ERIC Educational Resources Information Center

    van der Heijden, Beatrice I.J.M.; Boon, Jo; van der Klink, Marcel R.; Meys, Ely

    2008-01-01

    Not much is known about the actual contribution of informal learning to employability over and above formal learning activities. This paper presents findings of a research project among university staff members and is aimed to determine the contribution of formal and informal learning activities in the light of future career potential. Findings…

  14. Integrating Formal and Informal Learning at Work

    ERIC Educational Resources Information Center

    Svensson, Lennart; Ellstrom, Per-Erik; Aberg, Carina

    2004-01-01

    A model for workplace learning is presented, which intends to integrate formal and informal learning with the use of e-learning. An important underlying assumption is that the integration of formal and informal learning is necessary in order to create desirable competencies, from both an individual and an organisational perspective. Two case…

  15. Multifractal formalism and anisotropic selfsimilar functions

    NASA Astrophysics Data System (ADS)

    Ben Slimane, Mourad

    1998-09-01

    In this paper we prove that the conjectures of Frisch and Parisi and Arneodo et al. (called the multifractal formalism for functions) may fail for some non-homogeneous selfsimilar functions on [open face R]2. In these cases, we compute the correct spectrum of singularities and we show how the multifractal formalism must be modified.

  16. 39 CFR 3001.20 - Formal intervention.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 39 Postal Service 1 2013-07-01 2013-07-01 false Formal intervention. 3001.20 Section 3001.20... Applicability § 3001.20 Formal intervention. (a) Who may intervene. A notice of intervention will be entertained... interest of such nature that intervention is allowed by the Act, or appropriate to its administration....

  17. 39 CFR 3001.20 - Formal intervention.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 39 Postal Service 1 2010-07-01 2010-07-01 false Formal intervention. 3001.20 Section 3001.20... Applicability § 3001.20 Formal intervention. (a) Who may intervene. A notice of intervention will be entertained... interest of such nature that intervention is allowed by the Act, or appropriate to its administration....

  18. 39 CFR 3001.20 - Formal intervention.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 39 Postal Service 1 2011-07-01 2011-07-01 false Formal intervention. 3001.20 Section 3001.20... Applicability § 3001.20 Formal intervention. (a) Who may intervene. A notice of intervention will be entertained... interest of such nature that intervention is allowed by the Act, or appropriate to its administration....

  19. 39 CFR 3001.20 - Formal intervention.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 39 Postal Service 1 2014-07-01 2014-07-01 false Formal intervention. 3001.20 Section 3001.20... Applicability § 3001.20 Formal intervention. Link to an amendment published at 79 FR 33407, June 10, 2014. (a) Who may intervene. A notice of intervention will be entertained in those cases that are noticed for...

  20. 39 CFR 3001.20 - Formal intervention.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 39 Postal Service 1 2012-07-01 2012-07-01 false Formal intervention. 3001.20 Section 3001.20... Applicability § 3001.20 Formal intervention. (a) Who may intervene. A notice of intervention will be entertained... interest of such nature that intervention is allowed by the Act, or appropriate to its administration....

  1. 18 CFR 1b.5 - Formal investigations.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 18 Conservation of Power and Water Resources 1 2010-04-01 2010-04-01 false Formal investigations. 1b.5 Section 1b.5 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION, DEPARTMENT OF ENERGY GENERAL RULES RULES RELATING TO INVESTIGATIONS § 1b.5 Formal investigations....

  2. Do Formal Supports Replace Informal Supports?

    ERIC Educational Resources Information Center

    Barer, Barbara M.; And Others

    Health policy researchers have long been interested in the extent to which the provision of formal supports replaces or undermines the informal support system. This study examined the linkages between the formal and informal support system as they are mediated by a health care setting which readily provides patients with access to social services.…

  3. Restorative Practices as Formal and Informal Education

    ERIC Educational Resources Information Center

    Carter, Candice C.

    2013-01-01

    This article reviews restorative practices (RP) as education in formal and informal contexts of learning that are fertile sites for cultivating peace. Formal practices involve instruction about response to conflict, while informal learning occurs beyond academic lessons. The research incorporated content analysis and a critical examination of the…

  4. 37 CFR 251.41 - Formal hearings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ARBITRATION ROYALTY PANEL RULES AND PROCEDURES COPYRIGHT ARBITRATION ROYALTY PANEL RULES OF PROCEDURE Procedures of Copyright Arbitration Royalty Panels § 251.41 Formal hearings. (a) The formal hearings that... distribution hearings. All parties intending to participate in a hearing of a Copyright Arbitration...

  5. 37 CFR 251.41 - Formal hearings.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ARBITRATION ROYALTY PANEL RULES AND PROCEDURES COPYRIGHT ARBITRATION ROYALTY PANEL RULES OF PROCEDURE Procedures of Copyright Arbitration Royalty Panels § 251.41 Formal hearings. (a) The formal hearings that... distribution hearings. All parties intending to participate in a hearing of a Copyright Arbitration...

  6. Formal hardware verification of digital circuits

    NASA Technical Reports Server (NTRS)

    Joyce, J.; Seger, C.-J.

    1991-01-01

    The use of formal methods to verify the correctness of digital circuits is less constrained by the growing complexity of digital circuits than conventional methods based on exhaustive simulation. This paper briefly outlines three main approaches to formal hardware verification: symbolic simulation, state machine analysis, and theorem-proving.

  7. Methodological imperfection and formalizations in scientific activity

    SciTech Connect

    Svetlichny, G.

    1987-03-01

    Any mathematical formalization of scientific activity allows for imperfections in the methodology that is formalized. These can be of three types, dirty, rotten, and dammed. Restricting mathematical attention to those methods that cannot be construed to be imperfect drastically reduces the class of objects that must be analyzed, and related all other objects to these more regular ones. Examples are drawn from empirical logic.

  8. Multiverse in the Third Quantized Formalism

    NASA Astrophysics Data System (ADS)

    Mir, Faizal

    2014-11-01

    In this paper we will analyze the third quantization of gravity in path integral formalism. We will use the time-dependent version of Wheeler—DeWitt equation to analyze the multiverse in this formalism. We will propose a mechanism for baryogenesis to occur in the multiverse, without violating the baryon number conservation.

  9. Novel all-optical planar and compact minimum-stage switches of size >= 4x4

    NASA Astrophysics Data System (ADS)

    Giglmayr, Josef

    1997-01-01

    Throughout the paper, novel all-optical planar 1-stage k multiplied by k-switches and compact minimum-stage k multiplied by k-switches in double-layer and multi-layer technique, are presented and analyzed. In the first case, the number of k(k - 1)/2 switches of size 2 multiplied by 2 (equivalent minimum of the Spanke-Benes network) are arranged in parallel instead of the number of k (equivalent maximum) cascaded 2 multiplied by 2-switches of the Spanke- Benes network. In the second case, the number of 2 multiplied by 2-switches depends on the geometry of the 'pipes' of the switches formed by the layers and waveguides [for a square it is 3k/2(k/2 - 1) for rearrangeable nonblocking and 3(k - 1)k/2(k/2 - 1) for circuit switching networks]. The number of stages (NS) (horizontal cascaded) of the proposed compact switches for the nonblocking interconnection is NS equals n - 1 if the waveguides form an n-gon (n greater than or equal to 3) for any size of the k multiplied by k-switch. In this way, the attenuation of optical signals passing through a photonic network may be minimized. In particular, for any size of a k multiplied by k-switch, dependent on the n-gon, the minimum NS is n-1 equals 2 (triangle) or n - 1 equals 3 (square) etc. Thus the proposed switch concept is of complexity O(1), i.e. the NS is independent of the number of inputs/outputs. Additionally, the proposed switches are capable to operate in the circuit switching mode if and only if (iff) the parallelism increases by the factor k-1.

  10. Unified formalism for nonautonomous mechanical systems

    NASA Astrophysics Data System (ADS)

    Barbero-Liñán, María; Echeverría-Enríquez, Arturo; Diego, David Martín de; Muñoz-Lecanda, Miguel C.; Román-Roy, Narciso

    2008-06-01

    We present a unified geometric framework for describing both the Lagrangian and Hamiltonian formalisms of regular and nonregular time-dependent mechanical systems, which is based on the approach of Skinner and Rusk ["Generalized Hamiltonian dynamics I. Formulation on T*Q⊗TQ," J. Math. Phys. 24, 2589 (1983)]. The dynamical equations of motion and their compatibility and consistency are carefully studied, making clear that all the characteristics of the Lagrangian and the Hamiltonian formalisms are recovered in this formulation. As an example, a semidiscretization of the nonlinear wave equation is studied, proving the applicability of the proposed formalism.

  11. The Intersituational Generality of Formal Thought

    ERIC Educational Resources Information Center

    Stone, Mary Ann; Ausubel, David P.

    1969-01-01

    Shows that, contrary to Piagetian Theory, formal thought in a variety of subject matters is not possible until sufficient requisite concrete background experience in each content area involved has been attained. (MH)

  12. Formal specification of human-computer interfaces

    NASA Technical Reports Server (NTRS)

    Auernheimer, Brent

    1990-01-01

    A high-level formal specification of a human computer interface is described. Previous work is reviewed and the ASLAN specification language is described. Top-level specifications written in ASLAN for a library and a multiwindow interface are discussed.

  13. Importance of Reversibility in the Quantum Formalism

    NASA Astrophysics Data System (ADS)

    David, François

    2011-10-01

    In this Letter I stress the role of causal reversibility (time symmetry), together with causality and locality, in the justification of the quantum formalism. First, in the algebraic quantum formalism, I show that the assumption of reversibility implies that the observables of a quantum theory form an abstract real C⋆ algebra, and can be represented as an algebra of operators on a real Hilbert space. Second, in the quantum logic formalism, I emphasize which axioms for the lattice of propositions (the existence of an orthocomplementation and the covering property) derive from reversibility. A new argument based on locality and Soler’s theorem is used to derive the representation as projectors on a regular Hilbert space from the general quantum logic formalism. In both cases it is recalled that the restriction to complex algebras and Hilbert spaces comes from the constraints of locality and separability.

  14. A non-commuting stabilizer formalism

    SciTech Connect

    Ni, Xiaotong; Van den Nest, Maarten; Buerschaper, Oliver

    2015-05-15

    We propose a non-commutative extension of the Pauli stabilizer formalism. The aim is to describe a class of many-body quantum states which is richer than the standard Pauli stabilizer states. In our framework, stabilizer operators are tensor products of single-qubit operators drawn from the group 〈αI, X, S〉, where α = e{sup iπ/4} and S = diag(1, i). We provide techniques to efficiently compute various properties related to bipartite entanglement, expectation values of local observables, preparation by means of quantum circuits, parent Hamiltonians, etc. We also highlight significant differences compared to the Pauli stabilizer formalism. In particular, we give examples of states in our formalism which cannot arise in the Pauli stabilizer formalism, such as topological models that support non-Abelian anyons.

  15. Why Engineers Should Consider Formal Methods

    NASA Technical Reports Server (NTRS)

    Holloway, C. Michael

    1997-01-01

    This paper presents a logical analysis of a typical argument favoring the use of formal methods for software development, and suggests an alternative argument that is simpler and stronger than the typical one.

  16. Transitions from Formal Education to the Workplace

    ERIC Educational Resources Information Center

    Olson, Joann S.

    2014-01-01

    This chapter frames the transition to adulthood in the context of the moving from formal educational settings to the often less-structured learning that occurs in workplace settings. Although schooling may end, learning continues.

  17. Experiences Using Formal Methods for Requirements Modeling

    NASA Technical Reports Server (NTRS)

    Easterbrook, Steve; Lutz, Robyn; Covington, Rick; Kelly, John; Ampo, Yoko; Hamilton, David

    1996-01-01

    This paper describes three cases studies in the lightweight application of formal methods to requirements modeling for spacecraft fault protection systems. The case studies differ from previously reported applications of formal methods in that formal methods were applied very early in the requirements engineering process, to validate the evolving requirements. The results were fed back into the projects, to improve the informal specifications. For each case study, we describe what methods were applied, how they were applied, how much effort was involved, and what the findings were. In all three cases, the formal modeling provided a cost effective enhancement of the existing verification and validation processes. We conclude that the benefits gained from early modeling of unstable requirements more than outweigh the effort needed to maintain multiple representations.

  18. Further Examination of Formal Operational Reasoning Abilities.

    ERIC Educational Resources Information Center

    Roberge, James J.; Flexer, Barbara K.

    1979-01-01

    Three paper-and-pencil formal operations tests were administered to groups of eighth graders and adults. These measures provided scores that indicated each subject's level of reasoning for three second-order operations: combinations, proportionality, and propositional logic. (JMB)

  19. Open systems & non-formal education

    NASA Astrophysics Data System (ADS)

    Wheeler, Gerald F.

    1988-10-01

    Professor Dib created an important structure that can be used to attach the many and various activities that fall in the category of this title. While I plan to use his structure, I will be emphasizing a different component of his spectrum and promoting a different need. Professor Dib suggested a critical need to move our teaching styles away from formal modes to non-formal modes of delivery. I suggest an equally critical need in the area of informal education. And, I will propose aways to move us toward the same goal, non-formal activities. I believe we need to find ways to use the many informal education activities that occur almost automatically in our societies to move our potential learners to richer non-formal endeavors. Both needs are real; both activities are valid.

  20. General formalism for singly thermostated Hamiltonian dynamics.

    PubMed

    Ramshaw, John D

    2015-11-01

    A general formalism is developed for constructing modified Hamiltonian dynamical systems which preserve a canonical equilibrium distribution by adding a time evolution equation for a single additional thermostat variable. When such systems are ergodic, canonical ensemble averages can be computed as dynamical time averages over a single trajectory. Systems of this type were unknown until their recent discovery by Hoover and colleagues. The present formalism should facilitate the discovery, construction, and classification of other such systems by encompassing a wide class of them within a single unified framework. This formalism includes both canonical and generalized Hamiltonian systems in a state space of arbitrary dimensionality (either even or odd) and therefore encompasses both few- and many-particle systems. Particular attention is devoted to the physical motivation and interpretation of the formalism, which largely determine its structure. An analogy to stochastic thermostats and fluctuation-dissipation theorems is briefly discussed. PMID:26651677

  1. Design for validation, based on formal methods

    NASA Technical Reports Server (NTRS)

    Butler, Ricky W.

    1990-01-01

    Validation of ultra-reliable systems decomposes into two subproblems: (1) quantification of probability of system failure due to physical failure; (2) establishing that Design Errors are not present. Methods of design, testing, and analysis of ultra-reliable software are discussed. It is concluded that a design-for-validation based on formal methods is needed for the digital flight control systems problem, and also that formal methods will play a major role in the development of future high reliability digital systems.

  2. Methodological Imperfection and Formalizations of Scientific Activity

    NASA Astrophysics Data System (ADS)

    Svetlichny, George

    1987-03-01

    Any mathematical formalization of scientific activity allows for imperfections in the methodology that is formalized. These can be of three types, “dirty,” “rotten,” and “dammed.” Restricting mathematical attention to those methods that cannot be construed to be imperfect drastically reduces the class of objects that must be analyzed, and relates all other objects to these more regular ones. Examples are drawn from empirical logic.

  3. Formality of the Chinese collective leadership.

    PubMed

    Li, Haiying; Graesser, Arthur C

    2016-09-01

    We investigated the linguistic patterns in the discourse of four generations of the collective leadership of the Communist Party of China (CPC) from 1921 to 2012. The texts of Mao Zedong, Deng Xiaoping, Jiang Zemin, and Hu Jintao were analyzed using computational linguistic techniques (a Chinese formality score) to explore the persuasive linguistic features of the leaders in the contexts of power phase, the nation's education level, power duration, and age. The study was guided by the elaboration likelihood model of persuasion, which includes a central route (represented by formal discourse) versus a peripheral route (represented by informal discourse) to persuasion. The results revealed that these leaders adopted the formal, central route more when they were in power than before they came into power. The nation's education level was a significant factor in the leaders' adoption of the persuasion strategy. The leaders' formality also decreased with their increasing age and in-power times. However, the predictability of these factors for formality had subtle differences among the different types of leaders. These results enhance our understanding of the Chinese collective leadership and the role of formality in politically persuasive messages. PMID:27406253

  4. Formal verification of an avionics microprocessor

    NASA Technical Reports Server (NTRS)

    Srivas, Mandayam, K.; Miller, Steven P.

    1995-01-01

    Formal specification combined with mechanical verification is a promising approach for achieving the extremely high levels of assurance required of safety-critical digital systems. However, many questions remain regarding their use in practice: Can these techniques scale up to industrial systems, where are they likely to be useful, and how should industry go about incorporating them into practice? This report discusses a project undertaken to answer some of these questions, the formal verification of the AAMPS microprocessor. This project consisted of formally specifying in the PVS language a rockwell proprietary microprocessor at both the instruction-set and register-transfer levels and using the PVS theorem prover to show that the microcode correctly implemented the instruction-level specification for a representative subset of instructions. Notable aspects of this project include the use of a formal specification language by practicing hardware and software engineers, the integration of traditional inspections with formal specifications, and the use of a mechanical theorem prover to verify a portion of a commercial, pipelined microprocessor that was not explicitly designed for formal verification.

  5. (abstract) Formal Inspection Technology Transfer Program

    NASA Technical Reports Server (NTRS)

    Welz, Linda A.; Kelly, John C.

    1993-01-01

    A Formal Inspection Technology Transfer Program, based on the inspection process developed by Michael Fagan at IBM, has been developed at JPL. The goal of this program is to support organizations wishing to use Formal Inspections to improve the quality of software and system level engineering products. The Technology Transfer Program provides start-up materials and assistance to help organizations establish their own Formal Inspection program. The course materials and certified instructors associated with the Technology Transfer Program have proven to be effective in classes taught at other NASA centers as well as at JPL. Formal Inspections (NASA tailored Fagan Inspections) are a set of technical reviews whose objective is to increase quality and reduce the cost of software development by detecting and correcting errors early. A primary feature of inspections is the removal of engineering errors before they amplify into larger and more costly problems downstream in the development process. Note that the word 'inspection' is used differently in software than in a manufacturing context. A Formal Inspection is a front-end quality enhancement technique, rather than a task conducted just prior to product shipment for the purpose of sorting defective systems (manufacturing usage). Formal Inspections are supporting and in agreement with the 'total quality' approach being adopted by many NASA centers.

  6. Time-dependent Landauer—Büttiker formalism for superconducting junctions at arbitrary temperatures

    NASA Astrophysics Data System (ADS)

    Tuovinen, Riku; van Leeuwen, Robert; Perfetto, Enrico; Stefanucci, Gianluca

    2016-03-01

    We discuss an extension of our earlier work on the time-dependent Landauer- Buttiker formalism for noninteracting electronic transport. The formalism can without complication be extended to superconducting central regions since the Green's functions in the Nambu representation satisfy the same equations of motion which, in turn, leads to the same closed expression for the equal-time lesser Green's function, i.e., for the time-dependent reduced one-particle density matrix. We further write the finite-temperature frequency integrals in terms of known special functions thereby considerably speeding up the computation. Simulations in simple normal metal - superconductor - normal metal junctions are also presented.

  7. Fuzzy operators and cyclic behavior in formal neuronal networks

    NASA Technical Reports Server (NTRS)

    Labos, E.; Holden, A. V.; Laczko, J.; Orzo, L.; Labos, A. S.

    1992-01-01

    Formal neuronal networks (FNN), which are comprised of threshold gates, make use of the unit step function. It is regarded as a degenerated distribution function (DDF) and will be referred to here as a non-fuzzy threshold operator (nFTO). Special networks of this kind generating long cycles of states are modified by introduction of fuzzy threshold operators (FTO), i.e., non-degenerated distribution functions (nDDF). The cyclic behavior of the new nets is compared with the original ones. The interconnection matrix and threshold values are not modified. It is concluded that the original long cycles change the fixed points and short cycles, and as the computer simulations demonstrate, the aperiodic motion that is associated with chaotic behavior appears. The emergence of the above changes depend on the steepness of the threshold operators.

  8. Hybrid matrix fiber composites

    DOEpatents

    Deteresa, Steven J.; Lyon, Richard E.; Groves, Scott E.

    2003-07-15

    Hybrid matrix fiber composites having enhanced compressive performance as well as enhanced stiffness, toughness and durability suitable for compression-critical applications. The methods for producing the fiber composites using matrix hybridization. The hybrid matrix fiber composites include two chemically or physically bonded matrix materials, whereas the first matrix materials are used to impregnate multi-filament fibers formed into ribbons and the second matrix material is placed around and between the fiber ribbons that are impregnated with the first matrix material and both matrix materials are cured and solidified.

  9. Roulettes: a weak lensing formalism for strong lensing: I. Overview

    NASA Astrophysics Data System (ADS)

    Clarkson, Chris

    2016-08-01

    We present a new perspective on gravitational lensing. We describe a new extension of the weak lensing formalism capable of describing strongly lensed images. By integrating the nonlinear geodesic deviation equation, the amplification matrix of weak lensing is generalised to a sum over independent amplification tensors of increasing rank. We show how an image distorted by a generic lens may be constructed as a sum over ‘roulettes’, which are the natural curves associated with the independent spin modes of the amplification tensors. Highly distorted images can be constructed even for large sources observed near or within the Einstein radius of a lens where the shear and convergence are large. The amplitude of each roulette is formed from a sum over appropriate derivatives of the lensing potential. Consequently, measuring these individual roulettes for images around a lens gives a new way to reconstruct a strong lens mass distribution without requiring a lens model. This formalism generalises the convergence, shear and flexion of weak lensing to arbitrary order, and provides a unified bridge between the strong and weak lensing regimes. This overview paper is accompanied by a much more detailed paper II, arXiv:1603.04652.

  10. Formal Methods Case Studies for DO-333

    NASA Technical Reports Server (NTRS)

    Cofer, Darren; Miller, Steven P.

    2014-01-01

    RTCA DO-333, Formal Methods Supplement to DO-178C and DO-278A provides guidance for software developers wishing to use formal methods in the certification of airborne systems and air traffic management systems. The supplement identifies the modifications and additions to DO-178C and DO-278A objectives, activities, and software life cycle data that should be addressed when formal methods are used as part of the software development process. This report presents three case studies describing the use of different classes of formal methods to satisfy certification objectives for a common avionics example - a dual-channel Flight Guidance System. The three case studies illustrate the use of theorem proving, model checking, and abstract interpretation. The material presented is not intended to represent a complete certification effort. Rather, the purpose is to illustrate how formal methods can be used in a realistic avionics software development project, with a focus on the evidence produced that could be used to satisfy the verification objectives found in Section 6 of DO-178C.

  11. Formal methods for Hopfield-like networks.

    PubMed

    Ben Amor, Hedi; Corblin, Fabien; Fanchon, Eric; Elena, Adrien; Trilling, Laurent; Demongeot, Jacques; Glade, Nicolas

    2013-03-01

    Building a meaningful model of biological regulatory network is usually done by specifying the components (e.g. the genes) and their interactions, by guessing the values of parameters, by comparing the predicted behaviors to the observed ones, and by modifying in a trial-error process both architecture and parameters in order to reach an optimal fitness. We propose here a different approach to construct and analyze biological models avoiding the trial-error part, where structure and dynamics are represented as formal constraints. We apply the method to Hopfield-like networks, a formalism often used in both neural and regulatory networks modeling. The aim is to characterize automatically the set of all models consistent with all the available knowledge (about structure and behavior). The available knowledge is formalized into formal constraints. The latter are compiled into Boolean formula in conjunctive normal form and then submitted to a Boolean satisfiability solver. This approach allows to formulate a wide range of queries, expressed in a high level language, and possibly integrating formalized intuitions. In order to explore its potential, we use it to find cycles for 3-nodes networks and to determine the flower morphogenesis regulatory network of Arabidopsis thaliana. Applications of this technique are numerous and concern the building of models from data as well as the design of biological networks possessing specified behaviors. PMID:23381497

  12. Towards Formal Verification of a Separation Microkernel

    NASA Astrophysics Data System (ADS)

    Butterfield, Andrew; Sanan, David; Hinchey, Mike

    2013-08-01

    The best approach to verifying an IMA separation kernel is to use a (fixed) time-space partitioning kernel with a multiple independent levels of separation (MILS) architecture. We describe an activity that explores the cost and feasibility of doing a formal verification of such a kernel to the Common Criteria (CC) levels mandated by the Separation Kernel Protection Profile (SKPP). We are developing a Reference Specification of such a kernel, and are using higher-order logic (HOL) to construct formal models of this specification and key separation properties. We then plan to do a dry run of part of a formal proof of those properties using the Isabelle/HOL theorem prover.

  13. First order formalism for quantum gravity

    SciTech Connect

    Gleiser, M.; Holman, R.; Neto, N.P.

    1987-05-01

    We develop a first order formalism for the quantization of gravity. We take as canonical variables both the induced metric and the extrinsic curvature of the (d - 1) -dimensional hypersurfaces obtained by the foliation of the d - dimensional spacetime. After solving the constraint algebra we use the Dirac formalism to quantize the theory and obtain a new representation for the Wheeler-DeWitt equation, defined in the functional space of the extrinsic curvature. We also show how to obtain several different representations of the Wheeler-DeWitt equation by considering actions differing by a total divergence. In particular, the intrinsic and extrinsic time approaches appear in a natural way, as do equivalent representations obtained by functional Fourier transforms of appropriate variables. We conclude with some remarks about the construction of the Hilbert space within the first order formalism. 10 refs.

  14. Formalizing Darwinism and inclusive fitness theory.

    PubMed

    Grafen, Alan

    2009-11-12

    Inclusive fitness maximization is a basic building block for biological contributions to any theory of the evolution of society. There is a view in mathematical population genetics that nothing is caused to be maximized in the process of natural selection, but this is explained as arising from a misunderstanding about the meaning of fitness maximization. Current theoretical work on inclusive fitness is discussed, with emphasis on the author's 'formal Darwinism project'. Generally, favourable conclusions are drawn about the validity of assuming fitness maximization, but the need for continuing work is emphasized, along with the possibility that substantive exceptions may be uncovered. The formal Darwinism project aims more ambitiously to represent in a formal mathematical framework the central point of Darwin's Origin of Species, that the mechanical processes of inheritance and reproduction can give rise to the appearance of design, and it is a fitting ambition in Darwin's bicentenary year to capture his most profound discovery in the lingua franca of science. PMID:19805422

  15. The Interrelatedness of Formal, Non-Formal and Informal Learning: Evidence from Labour Market Program Participants

    ERIC Educational Resources Information Center

    Cameron, Roslyn; Harrison, Jennifer L.

    2012-01-01

    Definitions, differences and relationships between formal, non-formal and informal learning have long been contentious. There has been a significant change in language and reference from adult education to what amounts to forms of learning categorised by their modes of facilitation. Nonetheless, there is currently a renewed interest in the…

  16. MOOC & B-Learning: Students' Barriers and Satisfaction in Formal and Non-Formal Learning Environments

    ERIC Educational Resources Information Center

    Gutiérrez-Santiuste, Elba; Gámiz-Sánchez, Vanesa-M.; Gutiérrez-Pérez, Jose

    2015-01-01

    The study presents a comparative analysis of two virtual learning formats: one non-formal through a Massive Open Online Course (MOOC) and the other formal through b-learning. We compare the communication barriers and the satisfaction perceived by the students (N = 249) by developing a qualitative analysis using semi-structured questionnaires and…

  17. Formal and Non-Formal Digital Practices: Institutionalizing Transactional Learning Spaces in a Media Classroom

    ERIC Educational Resources Information Center

    de Lange, Thomas

    2011-01-01

    This article examines how a classroom procedure known as PGE (Plan/Go-through/Evaluate) group work aims at integrating formal and non-formal media experiences and practices into classroom-based media learning. The study displays, on the one hand, how PGE group work emerged and was institutionally embedded in a media course. On the other hand, the…

  18. Combining Formal, Non-Formal and Informal Learning for Workforce Skill Development

    ERIC Educational Resources Information Center

    Misko, Josie

    2008-01-01

    This literature review, undertaken for Australian Industry Group, shows how multiple variations and combinations of formal, informal and non-formal learning, accompanied by various government incentives and organisational initiatives (including job redesign, cross-skilling, multi-skilling, diversified career pathways, action learning projects,…

  19. The Comparative Functionality of Formal and Non-Formal Education for Women: Final Report.

    ERIC Educational Resources Information Center

    Derryck, Vivian Lowery

    This final report describes a five-phase study to ascertain whether formal or non-formal education has the greater functionality to accelerate women's integration into development activities. Part 1 (two chapters), introduction and background, defines the problem, sets parameters of the study, and provides definitions of education terms. Part 2…

  20. Extending the ADM formalism to Weyl geometry

    SciTech Connect

    Barreto, A. B.; Almeida, T. S.; Romero, C.

    2015-03-26

    In order to treat quantum cosmology in the framework of Weyl spacetimes we take the first step of extending the Arnowitt-Deser-Misner formalism to Weyl geometry. We then obtain an expression of the curvature tensor in terms of spatial quantities by splitting spacetime in (3+l)-dimensional form. We next write the Lagrangian of the gravitation field based in Weyl-type gravity theory. We extend the general relativistic formalism in such a way that it can be applied to investigate the quantum cosmology of models whose spacetimes are endowed with a Weyl geometrical structure.

  1. Educación no formal

    NASA Astrophysics Data System (ADS)

    Tignanelli, H.

    Se comentan en esta comunicación, las principales contribuciones realizadas en el campo de la educación en astronomía en los niveles primario, secundario y terciario, como punto de partida para la discusión de la actual inserción de los contenidos astronómicos en los nuevos contenidos curriculares de la EGB - Educación General Básica- y Polimodal, de la Reforma Educativa. En particular, se discuten los alcances de la educación formal y no formal, su importancia para la capacitación de profesores y maestros, y perspectivas a futuro.

  2. Keldysh formalism for multiple parallel worlds

    NASA Astrophysics Data System (ADS)

    Ansari, M.; Nazarov, Y. V.

    2016-03-01

    We present a compact and self-contained review of the recently developed Keldysh formalism for multiple parallel worlds. The formalism has been applied to consistent quantum evaluation of the flows of informational quantities, in particular, to the evaluation of Renyi and Shannon entropy flows. We start with the formulation of the standard and extended Keldysh techniques in a single world in a form convenient for our presentation. We explain the use of Keldysh contours encompassing multiple parallel worlds. In the end, we briefly summarize the concrete results obtained with the method.

  3. Density matrix embedding theory for interacting electron-phonon systems

    NASA Astrophysics Data System (ADS)

    Sandhoefer, Barbara; Chan, Garnet Kin-Lic

    2016-08-01

    We describe the extension of the density matrix embedding theory framework to coupled interacting fermion-boson systems. This provides a frequency-independent, entanglement embedding formalism to treat bulk fermion-boson problems. We illustrate the concepts within the context of the one-dimensional Hubbard-Holstein model, where the phonon bath states are obtained from the Schmidt decomposition of a self-consistently adjusted coherent state. We benchmark our results against accurate density matrix renormalization group calculations.

  4. Pauli theorem in the description of n-dimensional spinors in the Clifford algebra formalism

    NASA Astrophysics Data System (ADS)

    Shirokov, D. S.

    2013-04-01

    We discuss a generalized Pauli theorem and its possible applications for describing n-dimensional (Dirac, Weyl, Majorana, and Majorana-Weyl) spinors in the Clifford algebra formalism. We give the explicit form of elements that realize generalizations of Dirac, charge, and Majorana conjugations in the case of arbitrary space dimensions and signatures, using the notion of the Clifford algebra additional signature to describe conjugations. We show that the additional signature can take only certain values despite its dependence on the matrix representation

  5. 14 CFR 13.5 - Formal complaints.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... INVESTIGATIVE AND ENFORCEMENT PROCEDURES Investigative Procedures § 13.5 Formal complaints. (a) Any person may... purpose of seeking an appropriate order or other enforcement action; (2) Be submitted to the Federal... performance of official duties shall be referred to the Secretary of the Department concerned for action...

  6. Gravitational Compton Scattering from the Worldline Formalism

    NASA Astrophysics Data System (ADS)

    Ahmadiniaz, Naser; Corradini, Olindo; Dávila, José Manuel; Schubert, Christian

    2016-07-01

    We report on an ongoing study of photon amplitudes, graviton amplitudes and mixed photon-graviton amplitudes at tree-level using the worldline formalism. We explicitly recalculate the amplitude with one photon and one graviton coupled to a scalar propagator, relevant for graviton photoproduction. We comment on the factorization properties of this amplitude, and outline a generalization to similar processes involving more gravitons.

  7. 50 CFR 402.14 - Formal consultation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ..., DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Consultation Procedures § 402.14 Formal consultation. (a... established in accordance with 50 CFR 13.45 and 18.27 for FWS and 50 CFR 220.45 and 228.5 for NMFS. (4)...

  8. Conservation-dissipation formalism of irreversible thermodynamics

    NASA Astrophysics Data System (ADS)

    Zhu, Yi; Hong, Liu; Yang, Zaibao; Yong, Wen-An

    2015-06-01

    We propose a conservation-dissipation formalism (CDF) for coarse-grained descriptions of irreversible processes. This formalism is based on a stability criterion for non-equilibrium thermodynamics. The criterion ensures that non-equilibrium states tend to equilibrium in long time. As a systematic methodology, CDF provides a feasible procedure in choosing non-equilibrium state variables and determining their evolution equations. The equations derived in CDF have a unified elegant form. They are globally hyperbolic, allow a convenient definition of weak solutions, and are amenable to existing numerics. More importantly, CDF is a genuinely nonlinear formalism and works for systems far away from equilibrium. With this formalism, we formulate novel thermodynamics theories for heat conduction in rigid bodies and non-isothermal compressible Maxwell fluid flows as two typical examples. In these examples, the non-equilibrium variables are exactly the conjugate variables of the heat fluxes or stress tensors. The new theory generalizes Cattaneo's law or Maxwell's law in a regularized and nonlinear fashion.

  9. 14 CFR 302.20 - Formal intervention.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Formal intervention. 302.20 Section 302.20 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) PROCEDURAL REGULATIONS RULES OF PRACTICE IN PROCEEDINGS Rules of General Applicability Oral Evidentiary Hearing Proceedings § 302.20...

  10. 14 CFR 13.5 - Formal complaints.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Formal complaints. 13.5 Section 13.5... Aviation Administration, Office of the Chief Counsel, Attention: Enforcement Docket (AGC-10), 800... of the complaint are maintained in current docket form in the Enforcement Docket (AGC-10), Office...

  11. Quantum formalism to describe binocular rivalry.

    PubMed

    Manousakis, Efstratios

    2009-11-01

    On the basis of the general character and operation of the process of perception, a formalism is sought to mathematically describe the subjective or abstract/mental process of perception. It is shown that the formalism of orthodox quantum theory of measurement, where the observer plays a key role, is a broader mathematical foundation which can be adopted to describe the dynamics of the subjective experience. The mathematical formalism describes the psychophysical dynamics of the subjective or cognitive experience as communicated to us by the subject. Subsequently, the formalism is used to describe simple perception processes and, in particular, to describe the probability distribution of dominance duration obtained from the testimony of subjects experiencing binocular rivalry. Using this theory and parameters based on known values of neuronal oscillation frequencies and firing rates, the calculated probability distribution of dominance duration of rival states in binocular rivalry under various conditions is found to be in good agreement with available experimental data. This theory naturally explains an observed marked increase in dominance duration in binocular rivalry upon periodic interruption of stimulus and yields testable predictions for the distribution of perceptual alteration in time. PMID:19520143

  12. Leadership and Exchange in Formal Organizations.

    ERIC Educational Resources Information Center

    Jacobs, T. O.

    This volume reviews and reinterprets the existing literature on leadership, power, and influence processes; and provides a theoretical basis for understanding the leadership process in formal organizations. Numerous cited studies demonstrate that leadership is always relative to the situation; e.g., the effective leader makes a significant…

  13. Formal Schema Theory and Teaching EFL Reading

    ERIC Educational Resources Information Center

    Young, Barbara N; Man, Zhou

    2005-01-01

    Inquirers designed and conducted a study investigating whether or not results derived from previous research focusing on teaching and learning English as a native or foreign language would be replicated in a learning environment in which English is taught as a foreign language as in China. Because activation of formal schemata plays an important…

  14. Formal and Applied Counseling in Israel

    ERIC Educational Resources Information Center

    Israelashvili, Moshe; Wegman-Rozi, Orit

    2012-01-01

    Living in Israel is intensive and demanding but also meaningful and exciting. This article addresses the gap between the narrowly defined formal status of counseling in Israel and the widespread occurrence of counseling in various settings. It is argued that several recent changes, especially in the definition of treatment, along with the…

  15. Identifying Concrete and Formal Operational Children.

    ERIC Educational Resources Information Center

    Docherty, Edward M.

    This paper presents a study designed to determine if groups of concrete and formal operational children can be identified through the technique of cluster analysis, using a battery of Piagetian tasks. A Total of 64 subjects, 8 boys and 8 girls from each of the second, fourth, sixth, and eighth grade levels, were selected from a public elementary…

  16. Partial Derivative Automata Formalized in Coq

    NASA Astrophysics Data System (ADS)

    Almeida, José Bacelar; Moreira, Nelma; Pereira, David; de Sousa, Simão Melo

    In this paper we present a computer assisted proof of the correctness of a partial derivative automata construction from a regular expression within the Coq proof assistant. This proof is part of a formalization of Kleene algebra and regular languages in Coq towards their usage in program certification.

  17. External sources in field-antifield formalism

    NASA Astrophysics Data System (ADS)

    Batalin, Igor A.; Bering, Klaus

    2014-04-01

    We introduce external sources JA directly into the quantum master action W of the field-antifield formalism instead of the effective action. The external sources JA lead to a set of BRST-invariant functions WA that are in antisymplectic involution. As a byproduct, we encounter quasi-groups with open gauge algebras.

  18. Formal Synthesis of (±)-Roseophilin

    PubMed Central

    Bitar, Abdallah Y.; Frontier, Alison J.

    2009-01-01

    A formal synthesis of (±)-roseophilin is described. Scandium(III)-catalyzed Nazarov cyclization of 2,5-disubstituted N-tosylpyrrole 19 gives a 5,5’-fused ketopyrrole, and ansa-bridge formation via π-allyl palladium macrocyclization gives 21. PMID:19053717

  19. A Simplified Approach to Product Operator Formalism

    ERIC Educational Resources Information Center

    Spiese, Christopher E.

    2004-01-01

    The utilization of the simple and traditional vector model-based product operator formalism is highlighted. It is seen as a critical device in the area of nuclear magnetic resonance (NMR) spectrometry for a comprehensive analysis of spin coupling and quantum coherences.

  20. Formal Method of Description Supporting Portfolio Assessment

    ERIC Educational Resources Information Center

    Morimoto, Yasuhiko; Ueno, Maomi; Kikukawa, Isao; Yokoyama, Setsuo; Miyadera, Youzou

    2006-01-01

    Teachers need to assess learner portfolios in the field of education. However, they need support in the process of designing and practicing what kind of portfolios are to be assessed. To solve the problem, a formal method of describing the relations between the lesson forms and portfolios that need to be collected and the relations between…

  1. Connecting Formal and Informal Learning Experiences

    ERIC Educational Resources Information Center

    O'Mahony, Timothy Kieran

    2010-01-01

    The learning study reports on part of a larger project being lead by the author. In this dissertation I explore one goal of this project--to understand effects on student learning outcomes as a function of using different methods for connecting out-of-school experiential learning with formal school-based instruction. There is a long history of…

  2. The Transition to Formal Thinking in Mathematics

    ERIC Educational Resources Information Center

    Tall, David

    2008-01-01

    This paper focuses on the changes in thinking involved in the transition from school mathematics to formal proof in pure mathematics at university. School mathematics is seen as a combination of visual representations, including geometry and graphs, together with symbolic calculations and manipulations. Pure mathematics in university shifts…

  3. Preparing for Formal Proofs in Geometry

    ERIC Educational Resources Information Center

    Johnson, Art

    2009-01-01

    One way in which geometry teachers can help students develop their reasoning is by providing proof-readiness experiences. Blum and Kirsch (1991) suggest that "preformal proofs" can help students develop deductive reasoning. Preformal proofs, which follow the basic principles of deductive reasoning, can help prepare students for formal deduction in…

  4. 28 CFR 68.39 - Formal hearings.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Formal hearings. 68.39 Section 68.39 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) RULES OF PRACTICE AND PROCEDURE FOR ADMINISTRATIVE HEARINGS BEFORE ADMINISTRATIVE LAW JUDGES IN CASES INVOLVING ALLEGATIONS OF UNLAWFUL EMPLOYMENT OF ALIENS, UNFAIR IMMIGRATION-RELATED...

  5. Hearing-Impaired Formal Inservice Program.

    ERIC Educational Resources Information Center

    Northeast Regional Media Center for the Deaf, Amherst, MA.

    The HI-FI (Hearing-Impaired Formal Inservice) Program is described as a set of inservice materials targeted for workshops of regular classroom teachers and other school personnel concerned with school district and classroom management of hearing impaired (HI) children. An introductory section focuses on the design of the program materials,…

  6. An Elementary Formalism for General Relativity.

    ERIC Educational Resources Information Center

    diSessa, Andrea A.

    1981-01-01

    An elementary formalism is developed for representing curved space-time which allows transparent qualitative explanation of general relativistic effects and is used to make a conceptual analysis of Einstein's principle of equivalence. A final section outlines a number of student activities. (Author/SK)

  7. Safety in Children's Formal Play Environments.

    ERIC Educational Resources Information Center

    Wilkinson, Paul F.; Lockhart, Robert

    This study was designed to examine the issue of the safety of children's formal play environments. Safety was defined in terms of morbidity and mortality data. Protection and safety education were considered the prime factors in accident prevention while the goal of a safety program was considered to be the minimizing of injuries. Several data…

  8. Helping Students Understand Formal Chemical Concepts.

    ERIC Educational Resources Information Center

    Ward, Charles R.; Herron, J. Dudley

    1980-01-01

    Investigated outcomes of the use of the learning cycle, which divides instruction into the Piagetian phases of exploration, invention, and discovery in general college chemistry laboratory experiments. Differences between concrete and formal operational students were explored in students' ability to master chemistry material varying in cognitive…

  9. 50 CFR 402.14 - Formal consultation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 9 2011-10-01 2011-10-01 false Formal consultation. 402.14 Section 402.14 Wildlife and Fisheries JOINT REGULATIONS (UNITED STATES FISH AND WILDLIFE SERVICE, DEPARTMENT OF THE INTERIOR AND NATIONAL MARINE FISHERIES SERVICE, NATIONAL OCEANIC AND ATMOSPHERIC ADMINISTRATION, DEPARTMENT OF COMMERCE); ENDANGERED...

  10. 50 CFR 402.14 - Formal consultation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Consultation Procedures § 402.14 Formal consultation. (a... established in accordance with 50 CFR 13.45 and 18.27 for FWS and 50 CFR 220.45 and 228.5 for NMFS. (4)...

  11. 50 CFR 402.14 - Formal consultation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ..., DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Consultation Procedures § 402.14 Formal consultation. (a... established in accordance with 50 CFR 13.45 and 18.27 for FWS and 50 CFR 220.45 and 228.5 for NMFS. (4)...

  12. 50 CFR 402.14 - Formal consultation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., DEPARTMENT OF COMMERCE); ENDANGERED SPECIES COMMITTEE REGULATIONS SUBCHAPTER A INTERAGENCY COOPERATION-ENDANGERED SPECIES ACT OF 1973, AS AMENDED Consultation Procedures § 402.14 Formal consultation. (a... established in accordance with 50 CFR 13.45 and 18.27 for FWS and 50 CFR 220.45 and 228.5 for NMFS. (4)...

  13. Informal Science Learning in the Formal Classroom

    ERIC Educational Resources Information Center

    Walsh, Lori; Straits, William

    2014-01-01

    In this article the authors share advice from the viewpoints of both a formal and informal educator that will help teachers identify the right Informal Science Institutions (ISIs)--institutions that specialize in learning that occurs outside of the school setting--to maximize their students' learning and use informal education to their…

  14. Aspects of Financing Non-Formal Education.

    ERIC Educational Resources Information Center

    Morales, Francisco X. Swett

    1983-01-01

    Various financing structures for nonformal education are presented, using examples from Colombia, Brazil, Costa Rica, and Ecuador. Many resources of the formal education system can be used in the planning, coordination, and execution of nonformal education. The importance of community involvement and financial backing is stressed. (JA)

  15. 14 CFR 201.1 - Formal requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Formal requirements. 201.1 Section 201.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS AIR CARRIER AUTHORITY UNDER SUBTITLE VII OF TITLE 49 OF THE UNITED STATES CODE-...

  16. 14 CFR 201.1 - Formal requirements.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Formal requirements. 201.1 Section 201.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS AIR CARRIER AUTHORITY UNDER SUBTITLE VII OF TITLE 49 OF THE UNITED STATES CODE-...

  17. 14 CFR 201.1 - Formal requirements.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Formal requirements. 201.1 Section 201.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS AIR CARRIER AUTHORITY UNDER SUBTITLE VII OF TITLE 49 OF THE UNITED STATES CODE-...

  18. 14 CFR 201.1 - Formal requirements.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Formal requirements. 201.1 Section 201.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS AIR CARRIER AUTHORITY UNDER SUBTITLE VII OF TITLE 49 OF THE UNITED STATES CODE-...

  19. 14 CFR 201.1 - Formal requirements.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Formal requirements. 201.1 Section 201.1 Aeronautics and Space OFFICE OF THE SECRETARY, DEPARTMENT OF TRANSPORTATION (AVIATION PROCEEDINGS) ECONOMIC REGULATIONS AIR CARRIER AUTHORITY UNDER SUBTITLE VII OF TITLE 49 OF THE UNITED STATES CODE-...

  20. HIV Education in the Formal Curriculum

    ERIC Educational Resources Information Center

    Nsubuga, Yusuf K.; Bonnet, Sandrine

    2009-01-01

    The AIDS epidemic presents a complex of issues that require global answers, involving entire societies. The only sustainable solution is to include all sectors of society in a multidisciplinary collaboration, within which the formal education system plays a key role in delivering a comprehensive response to the disease at the national level.…

  1. Teaching Some Informatics Concepts Using Formal System

    ERIC Educational Resources Information Center

    Yang, Sojung; Park, Seongbin

    2014-01-01

    There are many important issues in informatics and many agree that algorithms and programming are most important issues that need to be included in informatics education (Dagiene and Jevsikova, 2012). In this paper, we propose how some of these issues can be easily taught using the notion of a formal system which consists of axioms and inference…

  2. Formal Foundations for Hierarchical Safety Cases

    NASA Technical Reports Server (NTRS)

    Denney, Ewen; Pai, Ganesh; Whiteside, Iain

    2015-01-01

    Safety cases are increasingly being required in many safety-critical domains to assure, using structured argumentation and evidence, that a system is acceptably safe. However, comprehensive system-wide safety arguments present appreciable challenges to develop, understand, evaluate, and manage, partly due to the volume of information that they aggregate, such as the results of hazard analysis, requirements analysis, testing, formal verification, and other engineering activities. Previously, we have proposed hierarchical safety cases, hicases, to aid the comprehension of safety case argument structures. In this paper, we build on a formal notion of safety case to formalise the use of hierarchy as a structuring technique, and show that hicases satisfy several desirable properties. Our aim is to provide a formal, theoretical foundation for safety cases. In particular, we believe that tools for high assurance systems should be granted similar assurance to the systems to which they are applied. To this end, we formally specify and prove the correctness of key operations for constructing and managing hicases, which gives the specification for implementing hicases in AdvoCATE, our toolset for safety case automation. We motivate and explain the theory with the help of a simple running example, extracted from a real safety case and developed using AdvoCATE.

  3. Formalism and the notion of truth

    NASA Astrophysics Data System (ADS)

    Spencer, Joseph M.

    The most widely acknowledged conceptions of truth take some kind of relation to be at truth's core. This dissertation attempts to establish that an adequate conception of this relation begins with an investigation of the entanglement of the formal and the material as set forth in the model theoretical development of set theoretical mathematics. Truth concerns first and most crucially a certain commerce across the border between the formal and the material, between the ideal and the real. The entanglement of the formal and the material must be thought in itself, apart from or prior to any assimilation into philosophical schemas committed to larger metaphysical claims. This is accomplished in model theory. The twentieth century witnessed two attempts at bringing model theoretical mathematics to bear on accounting philosophically for the concept of truth: that of Alfred Tarski, and that of Alain Badiou. In order to investigate the relevance of model theory to the task of working out a philosophical conception of truth, this dissertation investigates, through comparative work, these two thinkers. It is necessary to see where their projects converge in important ways, as well as where their projects diverge in equally important ways. What brings their work into close proximity is their shared conviction that truth must be thought in light of model theory. Nonetheless, the two do not agree about exactly how model theory sheds light on truth. Comparative study thus reveals both a shared site for thinking and a struggle over the significance of that site. Agreement between Tarski and Badiou concerns the excess of the purely formal over itself, marked by the generation of an undecidable statement within formal systems of a certain level of complexity. Both thinkers determine that this formal excess touches on the material, and both further determine that the consequent entanglement of the formal and the material provides the basic frame for any philosophical consideration

  4. Formally verifying Ada programs which use real number types

    NASA Technical Reports Server (NTRS)

    Sutherland, David

    1986-01-01

    Formal verification is applied to programs which use real number arithmetic operations (mathematical programs). Formal verification of a program P consists of creating a mathematical model of F, stating the desired properties of P in a formal logical language, and proving that the mathematical model has the desired properties using a formal proof calculus. The development and verification of the mathematical model are discussed.

  5. 20 CFR 702.347 - Formal hearings; termination.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 3 2011-04-01 2011-04-01 false Formal hearings; termination. 702.347 Section 702.347 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR LONGSHOREMEN... Adjudication Procedures Formal Hearings § 702.347 Formal hearings; termination. (a) Formal hearings...

  6. 20 CFR 702.347 - Formal hearings; termination.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 4 2013-04-01 2013-04-01 false Formal hearings; termination. 702.347 Section 702.347 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR LONGSHOREMEN... Adjudication Procedures Formal Hearings § 702.347 Formal hearings; termination. (a) Formal hearings...

  7. 20 CFR 702.347 - Formal hearings; termination.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 4 2014-04-01 2014-04-01 false Formal hearings; termination. 702.347 Section 702.347 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR LONGSHOREMEN... Adjudication Procedures Formal Hearings § 702.347 Formal hearings; termination. (a) Formal hearings...

  8. 20 CFR 702.347 - Formal hearings; termination.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 4 2012-04-01 2012-04-01 false Formal hearings; termination. 702.347 Section 702.347 Employees' Benefits OFFICE OF WORKERS' COMPENSATION PROGRAMS, DEPARTMENT OF LABOR LONGSHOREMEN... Adjudication Procedures Formal Hearings § 702.347 Formal hearings; termination. (a) Formal hearings...

  9. 20 CFR 702.347 - Formal hearings; termination.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Formal hearings; termination. 702.347 Section 702.347 Employees' Benefits EMPLOYMENT STANDARDS ADMINISTRATION, DEPARTMENT OF LABOR LONGSHOREMEN'S... Procedures Formal Hearings § 702.347 Formal hearings; termination. (a) Formal hearings are...

  10. 5 CFR 2638.309 - Reliance on formal advisory opinions.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 5 Administrative Personnel 3 2014-01-01 2014-01-01 false Reliance on formal advisory opinions... OF GOVERNMENT ETHICS AND EXECUTIVE AGENCY ETHICS PROGRAM RESPONSIBILITIES Formal Advisory Opinion Service § 2638.309 Reliance on formal advisory opinions. (a) Any formal advisory opinion referred to...

  11. 5 CFR 2638.309 - Reliance on formal advisory opinions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 5 Administrative Personnel 3 2010-01-01 2010-01-01 false Reliance on formal advisory opinions... OF GOVERNMENT ETHICS AND EXECUTIVE AGENCY ETHICS PROGRAM RESPONSIBILITIES Formal Advisory Opinion Service § 2638.309 Reliance on formal advisory opinions. (a) Any formal advisory opinion referred to...

  12. 5 CFR 2638.309 - Reliance on formal advisory opinions.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 5 Administrative Personnel 3 2013-01-01 2013-01-01 false Reliance on formal advisory opinions... OF GOVERNMENT ETHICS AND EXECUTIVE AGENCY ETHICS PROGRAM RESPONSIBILITIES Formal Advisory Opinion Service § 2638.309 Reliance on formal advisory opinions. (a) Any formal advisory opinion referred to...

  13. 20 CFR 702.336 - Formal hearings; new issues.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 3 2010-04-01 2010-04-01 false Formal hearings; new issues. 702.336 Section... Procedures Formal Hearings § 702.336 Formal hearings; new issues. (a) If, during the course of the formal hearing, the evidence presented warrants consideration of an issue or issues not previously...

  14. Formal methods demonstration project for space applications

    NASA Technical Reports Server (NTRS)

    Divito, Ben L.

    1995-01-01

    The Space Shuttle program is cooperating in a pilot project to apply formal methods to live requirements analysis activities. As one of the larger ongoing shuttle Change Requests (CR's), the Global Positioning System (GPS) CR involves a significant upgrade to the Shuttle's navigation capability. Shuttles are to be outfitted with GPS receivers and the primary avionics software will be enhanced to accept GPS-provided positions and integrate them into navigation calculations. Prior to implementing the CR, requirements analysts at Loral Space Information Systems, the Shuttle software contractor, must scrutinize the CR to identify and resolve any requirements issues. We describe an ongoing task of the Formal Methods Demonstration Project for Space Applications whose goal is to find an effective way to use formal methods in the GPS CR requirements analysis phase. This phase is currently under way and a small team from NASA Langley, ViGYAN Inc. and Loral is now engaged in this task. Background on the GPS CR is provided and an overview of the hardware/software architecture is presented. We outline the approach being taken to formalize the requirements, only a subset of which is being attempted. The approach features the use of the PVS specification language to model 'principal functions', which are major units of Shuttle software. Conventional state machine techniques form the basis of our approach. Given this background, we present interim results based on a snapshot of work in progress. Samples of requirements specifications rendered in PVS are offered to illustration. We walk through a specification sketch for the principal function known as GPS Receiver State processing. Results to date are summarized and feedback from Loral requirements analysts is highlighted. Preliminary data is shown comparing issues detected by the formal methods team versus those detected using existing requirements analysis methods. We conclude by discussing our plan to complete the remaining

  15. Formal concept analysis and linguistic hedges

    NASA Astrophysics Data System (ADS)

    Belohlavek, Radim; Vychodil, Vilem

    2012-07-01

    This paper presents an application of linguistic hedges to formal concept analysis of data with fuzzy attributes. Formal concept analysis aims at extraction of particular (bi-)clusters, called formal concepts, from data. The clusters link collections of objects (extents) and attributes (intents), and have a clear interpretation due to a simple verbal description of the concept-forming operators. We insert linguistic hedges such as 'very' or 'extremely' in the description of the operators. In this way, linguistic hedges become parameters for formal concept analysis that control the number of clusters extracted from data. Namely, as we show theoretically as well as experimentally, stronger hedges result in a smaller number of clusters. The new concept-forming operators form Galois-like connections. We study their properties and axiomatize them. Then, we show that a concept lattice with hedges, i.e. the set of all formal concepts of the new operators is indeed a complete lattice which is isomorphic to a particular ordinary concept lattice. We describe the isomorphism and its inverse. These mappings serve as translation procedures. As a consequence, we obtain a theorem characterizing the structure of concept lattices with hedges which generalizes the well-known main theorem of ordinary concept lattices. The isomorphism and its inverse enable us to compute a concept lattice with hedges using algorithms for ordinary concept lattices. We demonstrate by experiments that when selecting various hedges from the strongest to weaker hedges, the reduction in size of the corresponding concept lattices is smooth. From a broader perspective, we argue that linguistic hedges represent mathematically and computationally a feasible way to parameterize methods for knowledge extraction from data that enable one to emphasize or to suppress extracted patterns while keeping their interpretation.

  16. A matrix lower bound

    SciTech Connect

    Grcar, Joseph F.

    2002-02-04

    A matrix lower bound is defined that generalizes ideas apparently due to S. Banach and J. von Neumann. The matrix lower bound has a natural interpretation in functional analysis, and it satisfies many of the properties that von Neumann stated for it in a restricted case. Applications for the matrix lower bound are demonstrated in several areas. In linear algebra, the matrix lower bound of a full rank matrix equals the distance to the set of rank-deficient matrices. In numerical analysis, the ratio of the matrix norm to the matrix lower bound is a condition number for all consistent systems of linear equations. In optimization theory, the matrix lower bound suggests an identity for a class of min-max problems. In real analysis, a recursive construction that depends on the matrix lower bound shows that the level sets of continuously differential functions lie asymptotically near those of their tangents.

  17. Nonequilibrium problems in quantum field theory and Schwinger`s closed time path formalism

    SciTech Connect

    Cooper, F.

    1995-05-01

    We review the closed time path formalism of Schwinger using a path integral approach. We apply this formalism to the study of pair production from strong external fields as well as the time evolution of a nonequilibrium chiral phase transition. In 1961 in his classic paper ``Brownian Motion of a Quantum Particle,`` Schwinger solved the formidable technical problem of how to use the action principle to study initial value problems. Previously, the action principle was formulated to study only transition matrix elements from an earlier time to a later time. The elegant solution of this problem was the invention of the closed time path (CTP) formalism. This formalism was first used to study field theory problems by Mahanthappa and Bakshi. With the advent of supercomputers, it has now become possible to use this formalism to numerically solve important field theory questions which are presented as initial value problems. Two of these problems we shall review here. They are (1) The time evolution of the quark- gluon plasma. (2) Dynamical evolution of a non-equilibrium chiral phase transition following a relativistic heavy ion collision.

  18. A Screening Matrix for an Initial Line of Inquiry

    ERIC Educational Resources Information Center

    Nordness, Philip D.; Swain, Kristine D.; Haverkost, Ann

    2012-01-01

    The Screening for Understanding: Initial Line of Inquiry was designed to be used in conjunction with the child study team planning process for dealing with continuous problem behaviors prior to conducting a formal functional behavioral assessment. To conduct the initial line of inquiry a one-page reproducible screening matrix was used during child…

  19. Formal Safety Certification of Aerospace Software

    NASA Technical Reports Server (NTRS)

    Denney, Ewen; Fischer, Bernd

    2005-01-01

    In principle, formal methods offer many advantages for aerospace software development: they can help to achieve ultra-high reliability, and they can be used to provide evidence of the reliability claims which can then be subjected to external scrutiny. However, despite years of research and many advances in the underlying formalisms of specification, semantics, and logic, formal methods are not much used in practice. In our opinion this is related to three major shortcomings. First, the application of formal methods is still expensive because they are labor- and knowledge-intensive. Second, they are difficult to scale up to complex systems because they are based on deep mathematical insights about the behavior of the systems (t.e., they rely on the "heroic proof"). Third, the proofs can be difficult to interpret, and typically stand in isolation from the original code. In this paper, we describe a tool for formally demonstrating safety-relevant aspects of aerospace software, which largely circumvents these problems. We focus on safely properties because it has been observed that safety violations such as out-of-bounds memory accesses or use of uninitialized variables constitute the majority of the errors found in the aerospace domain. In our approach, safety means that the program will not violate a set of rules that can range for the simple memory access rules to high-level flight rules. These different safety properties are formalized as different safety policies in Hoare logic, which are then used by a verification condition generator along with the code and logical annotations in order to derive formal safety conditions; these are then proven using an automated theorem prover. Our certification system is currently integrated into a model-based code generation toolset that generates the annotations together with the code. However, this automated formal certification technology is not exclusively constrained to our code generator and could, in principle, also be

  20. Non-Formal Education: The Definitional Problem. Program of Studies in Non-Formal Education Discussion Papers Number 2.

    ERIC Educational Resources Information Center

    Kleis, Russell J.; And Others

    The three essays in this discussion paper present ways of structuring the concept of non-formal education. "Toward a Contextual Definition of Non-Formal Education" isolates three primary sub-systems: organizational, human, and curricular. Within these subsets non-formal education is differentiated from formal education by a more loosely integrated…

  1. Line Mixing in Parallel and Perpendicular Bands of CO2: A Further Test of the Refined Robert-Bonamy Formalism

    NASA Technical Reports Server (NTRS)

    Boulet, C.; Ma, Qiancheng; Tipping, R. H.

    2015-01-01

    Starting from the refined Robert-Bonamy formalism [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)], we propose here an extension of line mixing studies to infrared absorptions of linear polyatomic molecules having stretching and bending modes. The present formalism does not neglect the internal degrees of freedom of the perturbing molecules, contrary to the energy corrected sudden (ECS) modeling, and enables one to calculate the whole relaxation matrix starting from the potential energy surface. Meanwhile, similar to the ECS modeling, the present formalism properly accounts for roles played by all the internal angular momenta in the coupling process, including the vibrational angular momentum. The formalism has been applied to the important case of CO2 broadened by N2. Applications to two kinds of vibrational bands (sigma yields sigma and sigma yields pi) have shown that the present results are in good agreement with both experimental data and results derived from the ECS model.

  2. Line mixing in parallel and perpendicular bands of CO2: A further test of the refined Robert-Bonamy formalism.

    PubMed

    Boulet, C; Ma, Q; Tipping, R H

    2015-09-28

    Starting from the refined Robert-Bonamy formalism [Q. Ma, C. Boulet, and R. H. Tipping, J. Chem. Phys. 139, 034305 (2013)], we propose here an extension of line mixing studies to infrared absorptions of linear polyatomic molecules having stretching and bending modes. The present formalism does not neglect the internal degrees of freedom of the perturbing molecules, contrary to the energy corrected sudden (ECS) modelling, and enables one to calculate the whole relaxation matrix starting from the potential energy surface. Meanwhile, similar to the ECS modelling, the present formalism properly accounts for roles played by all the internal angular momenta in the coupling process, including the vibrational angular momentum. The formalism has been applied to the important case of CO2 broadened by N2. Applications to two kinds of vibrational bands (Σ → Σ and Σ → Π) have shown that the present results are in good agreement with both experimental data and results derived from the ECS model. PMID:26429017

  3. Formal Management of CAD/CAM Processes

    NASA Astrophysics Data System (ADS)

    Kohlhase, Michael; Lemburg, Johannes; Schröder, Lutz; Schulz, Ewaryst

    Systematic engineering design processes have many aspects in common with software engineering, with CAD/CAM objects replacing program code as the implementation stage of the development. They are, however, currently considerably less formal. We propose to draw on the mentioned similarities and transfer methods from software engineering to engineering design in order to enhance in particular the reliability and reusability of engineering processes. We lay out a vision of a document-oriented design process that integrates CAD/CAM documents with requirement specifications; as a first step towards supporting such a process, we present a tool that interfaces a CAD system with program verification workflows, thus allowing for completely formalised development strands within a semi-formal methodology.

  4. Generalizing Prototype Theory: A Formal Quantum Framework.

    PubMed

    Aerts, Diederik; Broekaert, Jan; Gabora, Liane; Sozzo, Sandro

    2016-01-01

    Theories of natural language and concepts have been unable to model the flexibility, creativity, context-dependence, and emergence, exhibited by words, concepts and their combinations. The mathematical formalism of quantum theory has instead been successful in capturing these phenomena such as graded membership, situational meaning, composition of categories, and also more complex decision making situations, which cannot be modeled in traditional probabilistic approaches. We show how a formal quantum approach to concepts and their combinations can provide a powerful extension of prototype theory. We explain how prototypes can interfere in conceptual combinations as a consequence of their contextual interactions, and provide an illustration of this using an intuitive wave-like diagram. This quantum-conceptual approach gives new life to original prototype theory, without however making it a privileged concept theory, as we explain at the end of our paper. PMID:27065436

  5. Analyzing phonetic confusions using formal concept analysis.

    PubMed

    Peláez-Moreno, C; García-Moral, A I; Valverde-Albacete, F J

    2010-09-01

    Confusion matrices have been used as a tool for the analysis of speech perception or human speech recognition (HSR) for decades. However, they are rarely employed in automatic speech recognition (ASR) mainly due to the lack of a systematic procedure for their exploration. The generalization of formal concept analysis employed in this paper provides a conceptual interpretation of confusion matrices that enables the analysis of the structure of confusions for both human and machine performances. Generalized formal concept analysis transforms confusion matrices into ordered lattices of confusion events, supporting classic results in HSR that identify a hierarchy of virtual articulatory-acoustic channels. Translating this technique into ASR, a detailed map of the relationships among the speech units employed in the system can be traced to make different sources of confusions apparent: the influence of the lexicon, segmentation errors, dialectal variations or limitations of the feature extraction procedures, among others. PMID:20815472

  6. Generalizing Prototype Theory: A Formal Quantum Framework

    PubMed Central

    Aerts, Diederik; Broekaert, Jan; Gabora, Liane; Sozzo, Sandro

    2016-01-01

    Theories of natural language and concepts have been unable to model the flexibility, creativity, context-dependence, and emergence, exhibited by words, concepts and their combinations. The mathematical formalism of quantum theory has instead been successful in capturing these phenomena such as graded membership, situational meaning, composition of categories, and also more complex decision making situations, which cannot be modeled in traditional probabilistic approaches. We show how a formal quantum approach to concepts and their combinations can provide a powerful extension of prototype theory. We explain how prototypes can interfere in conceptual combinations as a consequence of their contextual interactions, and provide an illustration of this using an intuitive wave-like diagram. This quantum-conceptual approach gives new life to original prototype theory, without however making it a privileged concept theory, as we explain at the end of our paper. PMID:27065436

  7. A Formal Basis for Safety Case Patterns

    NASA Technical Reports Server (NTRS)

    Denney, Ewen; Pai, Ganesh

    2013-01-01

    By capturing common structures of successful arguments, safety case patterns provide an approach for reusing strategies for reasoning about safety. In the current state of the practice, patterns exist as descriptive specifications with informal semantics, which not only offer little opportunity for more sophisticated usage such as automated instantiation, composition and manipulation, but also impede standardization efforts and tool interoperability. To address these concerns, this paper gives (i) a formal definition for safety case patterns, clarifying both restrictions on the usage of multiplicity and well-founded recursion in structural abstraction, (ii) formal semantics to patterns, and (iii) a generic data model and algorithm for pattern instantiation. We illustrate our contributions by application to a new pattern, the requirements breakdown pattern, which builds upon our previous work

  8. A Formal Framework for Workflow Analysis

    NASA Astrophysics Data System (ADS)

    Cravo, Glória

    2010-09-01

    In this paper we provide a new formal framework to model and analyse workflows. A workflow is the formal definition of a business process that consists in the execution of tasks in order to achieve a certain objective. In our work we describe a workflow as a graph whose vertices represent tasks and the arcs are associated to workflow transitions. Each task has associated an input/output logic operator. This logic operator can be the logical AND (•), the OR (⊗), or the XOR -exclusive-or—(⊕). Moreover, we introduce algebraic concepts in order to completely describe completely the structure of workflows. We also introduce the concept of logical termination. Finally, we provide a necessary and sufficient condition for this property to hold.

  9. Stochastic Formal Correctness of Numerical Algorithms

    NASA Technical Reports Server (NTRS)

    Daumas, Marc; Lester, David; Martin-Dorel, Erik; Truffert, Annick

    2009-01-01

    We provide a framework to bound the probability that accumulated errors were never above a given threshold on numerical algorithms. Such algorithms are used for example in aircraft and nuclear power plants. This report contains simple formulas based on Levy's and Markov's inequalities and it presents a formal theory of random variables with a special focus on producing concrete results. We selected four very common applications that fit in our framework and cover the common practices of systems that evolve for a long time. We compute the number of bits that remain continuously significant in the first two applications with a probability of failure around one out of a billion, where worst case analysis considers that no significant bit remains. We are using PVS as such formal tools force explicit statement of all hypotheses and prevent incorrect uses of theorems.

  10. Terra in K-16 formal education settings

    NASA Astrophysics Data System (ADS)

    Chambers, L. H.; Fischer, J. D.; Lewis, P. M.; Moore, S. W.; Oots, P. C.; Rogerson, T. M.; Hitke, K. M.; Riebeek, H.

    2009-12-01

    Since it began, the Terra mission has had an active presence in formal education at the K-16 level. This educational presence was provided through the S’COOL project for the first five years of the mission, joined by the MY NASA DATA project for the second five years. The Students’ Cloud Observations On-Line (S’COOL) Project, begun in 1997 under the auspices of the Clouds and the Earth’s Radiant Energy System (CERES) project, seeks to motivate students across the entire K-12 spectrum to learn science basics and how they tie in to a larger picture. Beginning early on, college level participants have also participated in the project, both in science classes and in science education coursework. The project uses the connection to an on-going NASA science investigation as a powerful motivator for student observations, analysis and learning, and has reached around the globe as shown in the world map. This poster will review the impact that Terra, through S’COOL, has made in formal education over the last decade. The MY NASA DATA Project began in 2004 under the NASA Research, Education and Applications Solutions Network (REASoN). A 5-year REASoN grant enabled the creation of an extensive website which wraps easily accessible Earth science data - including Terra parameters from CERES (involving MODIS data fusion), MISR, and MOPITT (an example for carbon monoxide is given in the graph, with dark areas indicating high CO levels) - with explanatory material written at the middle school level, and an extensive collection of peer-reviewed lesson plans. The MY NASA DATA site has a rapidly growing user-base and was recently adopted by a number of NASA Earth Science missions, in addition to Terra, as a formal education arm of their Education and Public Outreach efforts. This poster will summarize the contributions that Terra, through MY NASA DATA, has made to formal education since 2004.

  11. Toward a Formal Evaluation of Refactorings

    NASA Technical Reports Server (NTRS)

    Paul, John; Kuzmina, Nadya; Gamboa, Ruben; Caldwell, James

    2008-01-01

    Refactoring is a software development strategy that characteristically alters the syntactic structure of a program without changing its external behavior [2]. In this talk we present a methodology for extracting formal models from programs in order to evaluate how incremental refactorings affect the verifiability of their structural specifications. We envision that this same technique may be applicable to other types of properties such as those that concern the design and maintenance of safety-critical systems.

  12. Flexible receiver adapter formal design review

    SciTech Connect

    Krieg, S.A.

    1995-06-13

    This memo summarizes the results of the Formal (90%) Design Review process and meetings held to evaluate the design of the Flexible Receiver Adapters, support platforms, and associated equipment. The equipment is part of the Flexible Receiver System used to remove, transport, and store long length contaminated equipment and components from both the double and single-shell underground storage tanks at the 200 area tank farms.

  13. Decidability of formal theories and hyperincursivity theory

    NASA Astrophysics Data System (ADS)

    Grappone, Arturo G.

    2000-05-01

    This paper shows the limits of the Proof Standard Theory (briefly, PST) and gives some ideas of how to build a proof anticipatory theory (briefly, PAT) that has no such limits. Also, this paper considers that Gödel's proof of the undecidability of Principia Mathematica formal theory is not valid for axiomatic theories that use a PAT to build their proofs because the (hyper)incursive functions are self-representable.

  14. Fourth NASA Langley Formal Methods Workshop

    NASA Technical Reports Server (NTRS)

    Holloway, C. Michael (Compiler); Hayhurst, Kelly J. (Compiler)

    1997-01-01

    This publication consists of papers presented at NASA Langley Research Center's fourth workshop on the application of formal methods to the design and verification of life-critical systems. Topic considered include: Proving properties of accident; modeling and validating SAFER in VDM-SL; requirement analysis of real-time control systems using PVS; a tabular language for system design; automated deductive verification of parallel systems. Also included is a fundamental hardware design in PVS.

  15. Carbonate fuel cell matrix

    DOEpatents

    Farooque, M.; Yuh, C.Y.

    1996-12-03

    A carbonate fuel cell matrix is described comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles. 8 figs.

  16. Carbonate fuel cell matrix

    DOEpatents

    Farooque, Mohammad; Yuh, Chao-Yi

    1996-01-01

    A carbonate fuel cell matrix comprising support particles and crack attenuator particles which are made platelet in shape to increase the resistance of the matrix to through cracking. Also disclosed is a matrix having porous crack attenuator particles and a matrix whose crack attenuator particles have a thermal coefficient of expansion which is significantly different from that of the support particles, and a method of making platelet-shaped crack attenuator particles.

  17. [How to write an article: formal aspects].

    PubMed

    Corral de la Calle, M A; Encinas de la Iglesia, J

    2013-06-01

    Scientific research and the publication of the results of the studies go hand in hand. Exquisite research methods can only be adequately reflected in formal publication with the optimum structure. To ensure the success of this process, it is necessary to follow orderly steps, including selecting the journal in which to publish and following the instructions to authors strictly as well as the guidelines elaborated by diverse societies of editors and other institutions. It is also necessary to structure the contents of the article in a logical and attractive way and to use an accurate, clear, and concise style of language. Although not all the authors are directly involved in the actual writing, elaborating a scientific article is a collective undertaking that does not finish until the article is published. This article provides practical advice about formal and not-so-formal details to take into account when writing a scientific article as well as references that will help readers find more information in greater detail. PMID:23489765

  18. Extension of Liouville Formalism to Postinstability Dynamics

    NASA Technical Reports Server (NTRS)

    Zak, Michail

    2003-01-01

    A mathematical formalism has been developed for predicting the postinstability motions of a dynamic system governed by a system of nonlinear equations and subject to initial conditions. Previously, there was no general method for prediction and mathematical modeling of postinstability behaviors (e.g., chaos and turbulence) in such a system. The formalism of nonlinear dynamics does not afford means to discriminate between stable and unstable motions: an additional stability analysis is necessary for such discrimination. However, an additional stability analysis does not suggest any modifications of a mathematical model that would enable the model to describe postinstability motions efficiently. The most important type of instability that necessitates a postinstability description is associated with positive Lyapunov exponents. Such an instability leads to exponential growth of small errors in initial conditions or, equivalently, exponential divergence of neighboring trajectories. The development of the present formalism was undertaken in an effort to remove positive Lyapunov exponents. The means chosen to accomplish this is coupling of the governing dynamical equations with the corresponding Liouville equation that describes the evolution of the flow of error probability. The underlying idea is to suppress the divergences of different trajectories that correspond to different initial conditions, without affecting a target trajectory, which is one that starts with prescribed initial conditions.

  19. Matrix differentiation formulas

    NASA Technical Reports Server (NTRS)

    Usikov, D. A.; Tkhabisimov, D. K.

    1983-01-01

    A compact differentiation technique (without using indexes) is developed for scalar functions that depend on complex matrix arguments which are combined by operations of complex conjugation, transposition, addition, multiplication, matrix inversion and taking the direct product. The differentiation apparatus is developed in order to simplify the solution of extremum problems of scalar functions of matrix arguments.

  20. Matrix with Prescribed Eigenvectors

    ERIC Educational Resources Information Center

    Ahmad, Faiz

    2011-01-01

    It is a routine matter for undergraduates to find eigenvalues and eigenvectors of a given matrix. But the converse problem of finding a matrix with prescribed eigenvalues and eigenvectors is rarely discussed in elementary texts on linear algebra. This problem is related to the "spectral" decomposition of a matrix and has important technical…

  1. Rapid Mueller matrix polarimetry imaging based on four photoelastic modulators with no moving parts (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Gribble, Adam; Alali, Sanaz; Vitkin, Alex

    2016-03-01

    Polarized light has many applications in biomedical imaging. The interaction of a biological sample with polarized light reveals information about its composition, both structural and functional. For example, the polarimetry-derived metric of linear retardance (birefringence) is dependent on tissue structural organization (anisotropy) and can be used to diagnose myocardial infarct; circular birefringence (optical rotation) can measure glucose concentrations. The most comprehensive type of polarimetry analysis is to measure the Mueller matrix, a polarization transfer function that completely describes how a sample interacts with polarized light. To derive this 4x4 matrix it is necessary to observe how a tissue interacts with different polarizations. A well-suited approach for tissue polarimetry is to use photoelastic modulators (PEMs), which dynamically modulate the polarization of light. Previously, we have demonstrated a rapid time-gated Stokes imaging system that is capable of characterizing the state of polarized light (the Stokes vector) over a large field, after interacting with any turbid media. This was accomplished by synchronizing CCD camera acquisition times relative to two PEMs using a field-programmable gate array (FPGA). Here, we extend this technology to four PEMs, yielding a polarimetry system that is capable of rapidly measuring the complete sample Mueller matrix over a large field of view, with no moving parts and no beam steering. We describe the calibration procedure and evaluate the accuracy of the measurements. Results are shown for tissue-mimicking phantoms, as well as initial biological samples.

  2. Quaternionic Variational Formalism for General Relativity in Riemann and Riemann-Cartan Space-Times

    NASA Astrophysics Data System (ADS)

    Morita, K.

    2012-12-01

    It is shown that there exists a 2-dimensional matrix representation of complex quaternions over real quaternions, which allows to define Pauli matrix in 4 dimensions over the quaternionic field and leads to the quaternionic spinor group previously proposed. It is also attempted to apply complex quaternions to general relativity at the level of the variational formalism. Linear gravitational Lagrangian in Riemann-Cartan space-time U_4 is derived using quaternion caluculus; namely scalar curvature in U_4 is put into a quaternionic form. Consequently, Einstein-Hilbert Lagrangian in Riemann space R_4 is also defined over quaternions, as first shown by Sachs. The matter fields coupled to gravity are assumed to be the scalar and the Dirac fields. The quaternionic variational formalism corresponds to the first-order formalism but with a limited pattern of allowed fields such that the quaternionic fields carry only coordinate tensor indices but no local Lorentz indices which are contracted with that possessed by the basis of complex quaternions. In particular, both the quaternionic vierbein field and Lorentz gauge field (corresponding to the spin connection) are regarded as coordinate vectors which are independently varied, obtaining Einstein and Cartan equations, respectively. It is incidentally shown that the consistent condition of Einstein equation in U_4 is proved via the variational formalism and the anti-symmetric part of Einstein equation together with Cartan equation in U_4 leads to an identity which expresses the anti-symmetric part of the enegy-momentum tensor by means of the covariant divergence of the spin angular momentum tensor, both of Dirac field. We also present pedagogical proofs of Bianchi and Bach-Lanczos identities in U_4 using the quaternionic formalism.

  3. Nanocrystal doped matrixes

    DOEpatents

    Parce, J. Wallace; Bernatis, Paul; Dubrow, Robert; Freeman, William P.; Gamoras, Joel; Kan, Shihai; Meisel, Andreas; Qian, Baixin; Whiteford, Jeffery A.; Ziebarth, Jonathan

    2010-01-12

    Matrixes doped with semiconductor nanocrystals are provided. In certain embodiments, the semiconductor nanocrystals have a size and composition such that they absorb or emit light at particular wavelengths. The nanocrystals can comprise ligands that allow for mixing with various matrix materials, including polymers, such that a minimal portion of light is scattered by the matrixes. The matrixes of the present invention can also be utilized in refractive index matching applications. In other embodiments, semiconductor nanocrystals are embedded within matrixes to form a nanocrystal density gradient, thereby creating an effective refractive index gradient. The matrixes of the present invention can also be used as filters and antireflective coatings on optical devices and as down-converting layers. Processes for producing matrixes comprising semiconductor nanocrystals are also provided. Nanostructures having high quantum efficiency, small size, and/or a narrow size distribution are also described, as are methods of producing indium phosphide nanostructures and core-shell nanostructures with Group II-VI shells.

  4. Systematic errors for a Mueller matrix dual rotating compensator ellipsometer.

    PubMed

    Broch, Laurent; En Naciri, Aotmane; Johann, Luc

    2008-06-01

    The characterization of anisotropic materials and complex systems by ellipsometry has pushed the design of instruments to require the measurement of the full reflection Mueller matrix of the sample with a great precision. Therefore Mueller matrix ellipsometers have emerged over the past twenty years. The values of some coefficients of the matrix can be very small and errors due to noise or systematic errors can induce distored analysis. We present a detailed characterization of the systematic errors for a Mueller Matrix Ellipsometer in the dual-rotating compensator configuration. Starting from a general formalism, we derive explicit first-order expressions for the errors on all the coefficients of the Mueller matrix of the sample. The errors caused by inaccuracy of the azimuthal arrangement of the optical components and residual ellipticity introduced by imperfect optical elements are shown. A new method based on a four-zone averaging measurement is proposed to vanish the systematic errors. PMID:18545594

  5. A Formal Mentorship Program for Faculty Development

    PubMed Central

    Le, Jennifer; Nazer, Lama; Hess, Karl; Wang, Jeffrey; Law, Anandi V.

    2014-01-01

    Objective. To describe the development, implementation, and evaluation of a formal mentorship program at a college of pharmacy. Methods. After extensive review of the mentorship literature within the health sciences, a formal mentorship program was developed between 2006 and 2008 to support and facilitate faculty development. The voluntary program was implemented after mentors received training, and mentors and protégés were matched and received an orientation. Evaluation consisted of conducting annual surveys and focus groups with mentors and protégés. Results. Fifty-one mentor-protégé pairs were formed from 2009 to 2012. A large majority of the mentors (82.8%-96.9%) were satisfied with the mentorship program and its procedures. The majority of the protégés (≥70%) were satisfied with the mentorship program, mentor-protégé relationship, and program logistics. Both mentors and protégés reported that the protégés most needed guidance on time management, prioritization, and work-life balance. While there were no significant improvements in the proteges’ number of grant submissions, retention rates, or success in promotion/tenure, the total number of peer-reviewed publications by junior faculty members was significantly higher after program implementation (mean of 7 per year vs 21 per year, p=0.03) in the college’s pharmacy practice and administration department. Conclusions. A formal mentorship program was successful as measured by self-reported assessments of mentors and protégés. PMID:24954940

  6. Application of the green function formalism to nonlinear evolution of the low gain FEL oscillator

    SciTech Connect

    Shvets, G.; Wurtele, J.S.; Gardent, D.

    1995-12-31

    A matrix formalism for the optical pulse evolution in the frequency domain, is applied to the nonlinear regime of operation. The formalism was previously developed for studies of the linear evolution of the low-gain FEL oscillator with an arbitrary shape of the electron beam. By varying experimentally controllable parameters, such as cavity detunning and cavity losses, different regimes of operation of the FEL oscillator, such as a steady state saturation and limit cycle saturation, are studied numerically. It is demonstrated that the linear supermodes, numerically obtained from the matrix formalism, provide an appropriate framework for analyzing the periodic change in the output power in the limit cycle regime. The frequency of this oscillation is related to the frequencies of the lowest-order linear supermodes. The response of the output radiation to periodic variation of the electron energy is studied. It is found that the response is enhanced when the frequency of the energy variation corresponds to the difference of per-pass phase advances of the lowest linear supermodes. Finally, various nonlinear models are tested to capture the steady state saturation and limit cycle variation of the EM field in the oscillator cavity.

  7. Formal Assurance Arguments: A Solution In Search of a Problem?

    NASA Technical Reports Server (NTRS)

    Graydon, Patrick J.

    2015-01-01

    An assurance case comprises evidence and argument showing how that evidence supports assurance claims (e.g., about safety or security). It is unsurprising that some computer scientists have proposed formalizing assurance arguments: most associate formality with rigor. But while engineers can sometimes prove that source code refines a formal specification, it is not clear that formalization will improve assurance arguments or that this benefit is worth its cost. For example, formalization might reduce the benefits of argumentation by limiting the audience to people who can read formal logic. In this paper, we present (1) a systematic survey of the literature surrounding formal assurance arguments, (2) an analysis of errors that formalism can help to eliminate, (3) a discussion of existing evidence, and (4) suggestions for experimental work to definitively answer the question.

  8. QED spectra in the path integral formalism

    NASA Astrophysics Data System (ADS)

    Simonov, Yu. A.

    2014-07-01

    Relativistic Hamiltonians, derived from the path integrals, are known to provide a simple and useful formalism for hadron spectroscopy in QCD. The accuracy of this approach is tested using the QED systems, and the calculated spectrum is shown to reproduce exactly that of the Dirac hydrogen atom, while the Breit-Fermi nonrelativistic expansion is obtained using Foldy-Wouthuizen transformation. The calculated positronium spectrum, including spin-dependent terms, coincides with the standard QED perturbation theory to the considered order O(α4).

  9. Representations of spacetime: Formalism and ontological commitment

    NASA Astrophysics Data System (ADS)

    Bain, Jonathan Stanley

    This dissertation consists of two parts. The first is on the relation between formalism and ontological commitment in the context of theories of spacetime, and the second is on scientific realism. The first part begins with a look at how the substantivalist/relationist debate over the ontological status of spacetime has been influenced by a particular mathematical formalism, that of tensor analysis on differential manifolds (TADM). This formalism has motivated the substantivalist position known as manifold substantivalism. Chapter 1 focuses on the hole argument which maintains that manifold substantivalism is incompatible with determinism. I claim that the realist motivations underlying manifold substantivalism can be upheld, and the hole argument avoided, by adopting structural realism with respect to spacetime. In this context, this is the claim that it is the structure that spacetime points enter into that warrants belief and not the points themselves. In Chapter 2, an elimination principle is defined by means of which a distinction can be made between surplus structure and essential structure with respect to formulations of a theory in two distinct mathematical formulations and some prior ontological commitments. This principle is then used to demonstrate that manifold points may be considered surplus structure in the formulation of field theories. This suggests that, if we are disposed to read field theories literally, then, at most, it should be the essential structure common to all alternative formulations of such theories that should be taken literally. I also investigate how the adoption of alternative formalisms informs other issues in the philosophy of spacetime. Chapter 3 offers a realist position which takes a semantic moral from the preceding investigation and an epistemic moral from work done on reliability. The semantic moral advises us to read only the essential structure of our theories literally. The epistemic moral shows us that such structure

  10. Results of a Formal Methods Demonstration Project

    NASA Technical Reports Server (NTRS)

    Kelly, J.; Covington, R.; Hamilton, D.

    1994-01-01

    This paper describes the results of a cooperative study conducted by a team of researchers in formal methods at three NASA Centers to demonstrate FM techniques and to tailor them to critical NASA software systems. This pilot project applied FM to an existing critical software subsystem, the Shuttle's Jet Select subsystem (Phase I of an ongoing study). The present study shows that FM can be used successfully to uncover hidden issues in a highly critical and mature Functional Subsystem Software Requirements (FSSR) specification which are very difficult to discover by traditional means.